Integrated linear generator system

Abstract

An integrated linear generator system includes, for example, a generator assembly, a control system, a frame system, an exhaust system, an intake system, a cooling system, a bearing system, one or more auxiliary systems, or a combination thereof. The generator system is configured to generate power as controlled by the control system. The generator assembly may include opposed and free piston linear generators configured to operate over a two-stroke cycle. The intake and exhaust systems are configured to provide reactants to and remove products from the generator assembly, respectively. The cooling system is configured to effect heat transfer, material temperature, or both of components of the integrated linear generator system. The bearing system is configured to constrain off-axis movement of a translator of the generator assembly without applying significant frictional forces. The frame system is configured to manage stiffness, flexibility, and alignment of components of the integrated linear generator system.

Description

[0001] This application is a divisional application of the invention patent application named “Integrated Linear Generator System”, with an international application date of December 18, 2019, an international application number of PCT / US2019 / 067296, and a national application number of 201980092248.6.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] The present disclosure is directed to an integrated linear generator system and aspects thereof.This application claims the benefit of U.S. Provisional Patent Application No. 62 / 781,586, filed December 18, 2018, the disclosure of which is hereby incorporated by reference herein in its entirety. Background Art

[0004] Power generation systems usually rely on multiple subsystems working in coordination. For example, a typical crankshaft engine includes a rotating assembly including pistons, connecting rods, oil-immersed bearings and crankshafts, an oil supply system, a coolant system, an ignition system, a valvetrain and camshaft, a fuel system, and an exhaust system. These subsystems are adapted for crankshaft engines. Summary of the invention

[0005] In some embodiments, the present disclosure is directed to a linear generator. The linear generator includes a structural frame, a cylinder, a first linear electromagnetic machine (LEM), and a second LEM. The cylinder is attached to a central region of the structural frame. The LEM is arranged on a first longitudinal side of the cylinder and attached to the structural frame. The second LEM is arranged on a second longitudinal side of the cylinder and attached to the structural frame. The second longitudinal side is opposite to the first longitudinal side. The second LEM is aligned to the first LEM, and the cylinder is aligned to the first LEM and the second LEM. For example, in some embodiments, the first LEM is laterally aligned, axially aligned, or laterally and axially aligned to the second LEM. In some embodiments, the first LEM includes a first stator hole, the second LEM includes a second stator hole, and the first stator hole is aligned to the second stator hole. In some embodiments, the cylinder is attached to the structural frame by one or more flexible members. For example, in some embodiments, the one or more flexible members are stiffer with respect to lateral displacement than axial displacement.

[0006] In some embodiments, the linear generator includes a first gas spring cylinder attached to the structural frame and aligned to the first LEM, and a second gas spring cylinder attached to the structural frame and aligned to the second LEM.

[0007] In some embodiments, the structural frame includes one or more openings in the top surface. The one or more openings allow the cylinder to be inserted into the structural frame, allow the first LEM to be inserted into the structural frame, and allow the second LEM to be inserted into the structural frame.

[0008] In some embodiments, the linear generator comprises at least one mount attached to the frame. The linear generator is operable within one or more frequency ranges, and the mount is capable of attenuating vibrations from the linear generator.

[0009] In some embodiments, the structural frame includes one or more end members that allow for axial thermal expansion and maintain lateral stiffness.

[0010] In some embodiments, the present disclosure is directed to a linear generator comprising a structural frame, a cylinder, a first stator, and a second stator. The cylinder is attached to a central region of the structural frame,

[0011] The first stator is arranged on a first longitudinal side of the cylinder and attached to the structural frame, and the second stator is arranged on a second longitudinal side of the cylinder and attached to the structural frame. The second longitudinal side is opposite to the first side, the second stator is aligned to the first stator, and the cylinder is aligned to the first stator and the second stator.

[0012] In some embodiments, the linear generator comprises a first translator arranged to interact with both the first stator and the cylinder, and

[0013] A second translator arranged to interact with both the second stator and the cylinder. In some embodiments, the linear generator comprises one or more first gas bearing housings constraining the first translator relative to the first stator, and one or more second gas bearing housings constraining the second translator relative to the second stator. In some embodiments, each translator comprises a first piston arranged to move along the axis of the cylinder, and a magnet segment interacting with the corresponding stator. For example, the opposing pistons of the translators define a reaction segment of the cylinder.

[0014] In some embodiments, the structural frame includes one or more end members, wherein the one or more end members allow for axial thermal expansion and maintain lateral stiffness.

[0015] In some embodiments, the present disclosure is directed to a structural frame for mounting components of a linear generator. The structural frame includes one or more components for providing axial and lateral stiffness, a first mounting area for receiving the one or more components of a first LEM, a second mounting area for receiving the one or more components of a second LEM, a third mounting area for receiving the one or more components of a cylinder, and one or more openings among the one or more components. The one or more openings correspond to the first mounting area, the second mounting area, and the third mounting area.

[0016] In some embodiments, the one or more openings are arranged on a top side of the structural frame such that a first mounting area receives a first LEM through the top side, a second mounting area receives a second LEM through the top side, and a third mounting area receives a cylinder through the top side.

[0017] In some embodiments, the structural frame includes one or more end members coupled to the one or more members. The one or more end members allow for axial thermal expansion and maintain lateral stiffness. In some embodiments, the first mounting area, the second mounting area, and the third mounting area are axially and laterally aligned.

[0018] In some embodiments, the present disclosure is directed to a linear generator including an air intake system. The air intake system is configured to provide intake air to a reaction section.

[0019] In some embodiments, the present disclosure is directed to a linear generator including an exhaust system. The exhaust system is configured to remove exhaust gas from a reaction section.

[0020] In some embodiments, the present disclosure is directed to a linear generator including a fuel system. The fuel system is configured to provide fuel to mix with incoming air upstream of or in a reaction section.

[0021] In some embodiments, the present disclosure is directed to a linear generator including an electrical system configured to manage electrical interactions, such as power management, control signals, sensor circuitry, control circuitry, and other circuitry.

[0022] In some embodiments, the present disclosure is directed to a linear generator including a control system configured to communicate with sensors, receive sensor signals, generate control signals, determine operating parameters, execute computer instructions, and otherwise control operation and characterize aspects of the linear generator.

[0023] In some embodiments, the present disclosure is directed to a system comprising one or more cores. For example, each core may comprise a linear generator or generator assembly.

[0024] In some embodiments, the present disclosure is directed to a linear generator including a cooling system. The cooling system is configured to manage heat flow and temperature of the linear generator.

[0025] In some embodiments, the present disclosure is directed to a linear generator including a bearing system. The bearing system is configured to manage bearing stiffness and operation. For example, the bearing system manages a gas bearing (eg, pressure, flow, or both of the gas bearing). BRIEF DESCRIPTION OF THE DRAWINGS

[0026] According to one or more various embodiments, the present disclosure is described in detail with reference to the accompanying drawings. The drawings are provided for illustrative purposes only and depict only typical embodiments or example embodiments. These drawings are provided to facilitate understanding of the concepts disclosed herein and should not be considered to limit the breadth, scope or applicability of these concepts. It should be noted that for clarity and ease of illustration, these drawings are not necessarily drawn to scale.

[0027] Figure 1 A system diagram showing an illustrative integrated linear generator system according to some embodiments of the present disclosure;

[0028] Figure 2 showing a cross-sectional side view of an illustrative generator assembly according to some embodiments of the present disclosure;

[0029] Figure 3 is a block diagram of an illustrative linear generator including a control system for controlling operation of the generator assembly according to some embodiments of the present disclosure;

[0030] Figure 4 shows a portion of an illustrative generator assembly having a reaction section piston in various respective axial positions according to some embodiments of the present disclosure;

[0031] Figure 5 showing a portion of an illustrative generator assembly having lean-fronting according to some embodiments of the present disclosure;

[0032] Figure 6 showing two cross-sectional views of an illustrative translator having a reservoir according to some embodiments of the present disclosure;

[0033] Figure 7 A system diagram showing an illustrative air intake system according to some embodiments of the present disclosure;

[0034] Figure 8 showing a side view of an illustrative vent port in a cylinder according to some embodiments of the present disclosure;

[0035] Fig. 9 Demonstrating some embodiments of the present disclosure Figure 8 A cross-sectional end view of an illustrative cylinder block;

[0036] Fig.10 showing a side view of an illustrative vent port in a cylinder sized and arranged to reduce hoop stress according to some embodiments of the present disclosure;

[0037] Fig.11 showing a cross-sectional end view of an illustrative shaped vent port in a cylinder according to some embodiments of the present disclosure;

[0038] Fig.12 showing a cross-sectional end view of an illustrative shaped vent port in a cylinder according to some embodiments of the present disclosure;

[0039] Fig.13 showing a cross-sectional view of a portion of an illustrative integrated linear generator system configured for premixed air and fuel according to some embodiments of the present disclosure;

[0040] Fig.14 showing a cross-sectional view of a portion of an illustrative integrated linear generator system configured for in-port injection according to some embodiments of the present disclosure;

[0041] Fig.15 showing a cross-sectional view of a portion of an illustrative integrated linear generator system configured for injection according to some embodiments of the present disclosure;

[0042] Fig.16 showing a cross-sectional side view of an illustrative air intake portion of a linear generator according to some embodiments of the present disclosure;

[0043] Fig.17 showing a cross-sectional side view of an illustrative air intake portion of a linear generator according to some embodiments of the present disclosure;

[0044] Fig.18 A system diagram showing an illustrative fuel system according to some embodiments of the present disclosure;

[0045] Fig.19 a system diagram showing an illustrative exhaust system according to some embodiments of the present disclosure;

[0046] Fig. 20 showing a cross-sectional view of a portion of an illustrative integrated linear generator system configured for exhaust according to some embodiments of the present disclosure;

[0047] Fig.21 shows a cross-sectional view of an illustrative exhaust manifold according to some embodiments of the present disclosure;

[0048] Fig. 22 showing a cross-sectional view of an illustrative gas spring system according to some embodiments of the present disclosure;

[0049] Fig.23 showing a cross-sectional side view of an illustrative gas spring system having a reservoir according to some embodiments of the present disclosure;

[0050] Fig.24 Showing a device having a translator in a second position according to some embodiments of the present disclosure Fig.23 A cross-sectional side view of an illustrative gas spring system;

[0051] Fig.25showing a cross-sectional side view of an illustrative gas spring system having a reservoir configured for intake gas compression in accordance with some embodiments of the present disclosure;

[0052] Fig.26 showing a side cross-sectional view of a portion of an illustrative gas spring system having a reservoir according to some embodiments of the present disclosure;

[0053] Fig. 27 showing a side cross-sectional view of a portion of an illustrative gas spring system having a reservoir according to some embodiments of the present disclosure;

[0054] Fig.28 showing a side cross-sectional view of a portion of an illustrative gas spring system having a reservoir according to some embodiments of the present disclosure;

[0055] Fig.29 showing several perspective views of illustrative gas spring systems according to some embodiments of the present disclosure;

[0056] Fig.30 shows a side cross-sectional view of an illustrative gas spring cylinder assembly according to some embodiments of the present disclosure;

[0057] Fig.31 Demonstrating the use of a sliding bushing to open according to some embodiments of the present disclosure Fig.30 A side cross-sectional view of an illustrative gas spring cylinder assembly;

[0058] Fig.32 A system diagram showing an illustrative bearing system according to some embodiments of the present disclosure;

[0059] Fig.33 showing a cross-sectional view of a portion of an illustrative generator assembly according to some embodiments of the present disclosure;

[0060] Fig.34 showing a cross-sectional view of a portion of an illustrative generator assembly according to some embodiments of the present disclosure;

[0061] Fig.35 showing a cross-sectional view of a portion of an illustrative generator assembly according to some embodiments of the present disclosure;

[0062] Fig.36 A seal having a seal positioned axially in front of the intake port is shown according to some embodiments of the present disclosure. Fig.34 an enlarged view of a section of an illustrative generator assembly portion of;

[0063] Fig.37 A piston seal having a piston seal axially positioned behind the intake port is shown according to some embodiments of the present disclosure. Fig.34an enlarged view of a section of an illustrative generator assembly portion of;

[0064] Fig.38 showing an enlarged view of a section of an illustrative generator assembly portion according to some embodiments of the present disclosure;

[0065] Fig.39A showing a cross-sectional view of a portion of an illustrative generator assembly having a seal within a ring compressor according to some embodiments of the present disclosure;

[0066] Fig.39B A seal having a seal around the outside of a compressor is shown according to some embodiments of the present disclosure. Fig.39A A cross-sectional view of a portion of an illustrative generator assembly;

[0067] Fig.40 showing a cross-sectional view of a portion of an illustrative generator assembly having an intake seal according to some embodiments of the present disclosure;

[0068] Fig.41 showing a cross-sectional view of a portion of an illustrative generator assembly having an intake manifold sealed against a bearing housing according to some embodiments of the present disclosure;

[0069] Fig.42 showing a side view of an illustrative translator according to some embodiments of the present disclosure,

[0070] Fig.43 Demonstrating some embodiments of the present disclosure Fig.42 An axial end view of an illustrative translator;

[0071] Fig.44 shows a side cross-sectional view of an illustrative translator having a tapered region and optional spacers according to some embodiments of the present disclosure;

[0072] Fig.45 showing a side cross-sectional view of an end of an illustrative translator tube and a rail having a cantilevered section according to some embodiments of the present disclosure;

[0073] Fig.46 a perspective view showing an end of an illustrative translator tube coupled to a piston via a fastener in accordance with some embodiments of the present disclosure;

[0074] Fig.47 a perspective view showing an end of an illustrative translator tube coupled to a piston via an obliquely oriented fastener in accordance with some embodiments of the present disclosure;

[0075] Fig.48 showing an end view of an illustrative translator and additional components according to some embodiments of the present disclosure;

[0076] Fig.49 showing cross-sectional views of illustrative translators and stators and enlarged portions according to some embodiments of the present disclosure;

[0077] Fig.50 showing a cross-sectional view of an illustrative translator and stator according to some embodiments of the present disclosure;

[0078] Fig.51 showing a cross-sectional view of an illustrative translator and bearing housing according to some embodiments of the present disclosure;

[0079] Fig.52 a system diagram showing an illustrative cooling system according to some embodiments of the present disclosure;

[0080] Fig.53 showing a top view of an illustrative frame system according to some embodiments of the present disclosure;

[0081] Fig.54 showing a side view of an illustrative frame system according to some embodiments of the present disclosure;

[0082] Fig.55 showing a side view of an illustrative assembly including a frame system coupled to a generator assembly according to some embodiments of the present disclosure;

[0083] Fig.56 showing an end view of an illustrative frame system according to some embodiments of the present disclosure;

[0084] Fig.57 showing a cross-sectional view of an illustrative portion of an integrated linear generator system including an end member, a gas spring cylinder, and a head according to some embodiments of the present disclosure;

[0085] Fig.58 shows a side view of an illustrative assembly including a cylinder block with a mount according to an embodiment of the present disclosure;

[0086] Fig.59 An illustrative cylinder block assembly having an intake manifold with mountings is shown according to some embodiments of the present disclosure;

[0087] Fig.60 showing a perspective view of an illustrative core according to some embodiments of the present disclosure; and

[0088] Fig.61 A perspective view is shown of an illustrative system including two cores according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0089] In some embodiments, the present disclosure provides a linear generator system configured to provide electrical work (i.e., electricity) from the input of fuel and oxidant. In some embodiments, the present disclosure provides a linear system configured to convert between kinetic energy and electrical energy. In some embodiments, the linear generator includes a pair of opposing oscillating translators arranged along an axis. Both translators contact a single compression or reaction section, and each translator also contacts a corresponding driver section (e.g., a gas spring). As each translator moves along the axis, the compression or reaction section and the gas spring alternately compress and expand. In some embodiments, there is no mechanical linkage mechanism between the translators (i.e., a linear pistonless generator or a linear translatorless generator). Electrical work is extracted from the linear generator via a multiphase stator, which is configured to interact with the translator electromagnetically as the translator moves.

[0090] Figure 1 A system diagram of an illustrative integrated linear generator system 100 is shown in accordance with some embodiments of the present disclosure. Integrated linear generator system 100 includes generator assembly 102, control system 104, electrical system 105, frame system 106, exhaust system 108, intake system 110, cooling system 112, bearing system 114, and auxiliary system 116. Generator system 100 is configured to generate and manage electrical power as controlled by control system 104 and electrical system 105. In some embodiments, electrical system 105 includes both low voltage and high voltage components. For example, the electrical system 105 may include 480VAC components (e.g., a grid or grid-connected components, auxiliary components), 120VAC components / circuits (e.g., auxiliary components), high voltage DC bus and components (e.g., >400VDC, >700VDC, or >1000VDC components), low voltage DC bus and components (e.g., 12VDC, 24VDC, or 48VDC components), low voltage DC components (e.g., 12VDC, 24VDC, or 48VDC components), any other suitable circuits operating with any suitable voltage and current characteristics, or any combination thereof. The intake system 110 is configured to provide reactants (e.g., air, fuel, or both) to the generator assembly 102, and the exhaust system 108 is configured to remove exhaust products from the generator assembly 102. The cooling system 112 is configured to limit, control, or otherwise affect heat transfer and material temperatures of components of the integrated linear generator system 100. The bearing system 114 is configured to constrain off-axis motion (e.g., radial, lateral, or other lateral motion) of the translator of the generator assembly 102 using, for example, low friction gas bearings. The frame system 106 is configured to manage the rigidity, flexibility, and alignment of the components of the integrated linear generator system 100. The division between systems 102-114 or the combination of systems 102-114 may be implemented in any suitable arrangement and is described below for purposes of the following description. Figure 1For example, any suitable components of the control system 104, electrical system 105, frame system 106, bearing system 114, intake system 110, exhaust system 108, and cooling system 112 may be integral with the generator assembly 102. Auxiliary system 116 may include any suitable system or subsystem configured to support the operation of the integrated linear generator system 100.

[0091] It should be understood that system 100 is illustrative only. Any suitable combination of subsystems may be used, including systems including Figure 1 Fewer or more subsystems may be shown.

[0092] The generator assembly 102 includes, for example, mobile and fixed assemblies and components configured to convert chemical and / or thermal energy into electrical energy. In some embodiments, the generator assembly 102 includes a cylinder block, a translator, a stator, bearings, a bearing housing, a seal, corresponding alignment hardware, any other suitable components, or any suitable combination thereof. In some embodiments, the generator assembly 102 is configured to perform a thermodynamic cycle such as a chemical engine cycle. Illustrative examples include a two-stroke piston engine cycle using compression ignition and port ventilation (via direct current scavenging) (e.g., an intake port at a first axial end and an exhaust port arranged at a second axial end, where scavenging occurs primarily axially). In another example, the generator assembly 102 can be configured to perform a cycle that approximates, for example, an Otto cycle, a Diesel cycle, an Atkinson cycle, a Miller cycle, a Carnot cycle, an Ericsson cycle, a Stirling cycle, any other suitable ideal or actual cycle, or any suitable combination thereof.

[0093] Figure 2A cross-sectional view of an illustrative generator assembly 200 is shown according to some embodiments of the present disclosure. The generator assembly 200 is configured as a relative generator. The generator assembly 200 includes translators 210 and 220, which are configured to move along axis 206 (e.g., linearly translate along axis 206). The translators 210 and 220 are configured to move within cylinders 202, 204, and 205, thereby forming expansion and compression volumes 297, 298, and 299 for performing boundary work (e.g., determined using a cycle integral of PdV over a suitable range such as stroke or cycle). For clarity, the spatial arrangement of the systems and assemblies described herein will generally be referenced to cylindrical coordinates having axial, radial, and azimuthal directions. It should be understood that any suitable coordinate system may be used (e.g., cylindrical coordinates may be mapped to any suitable coordinate system) in accordance with the present disclosure. Note that the axis 206 is oriented in an axial direction, and a radial direction is defined as perpendicular to the axis 206 (e.g., oriented away from the axis 206). An azimuthal direction is defined as an angular direction about the axis 206 (e.g., orthogonal to both the axis 206 and the radial direction, and oriented about the axis 206).

[0094] In some embodiments, the stationary components of the generator assembly 200 include the cylinder 202, the cylinder 204, the cylinder 205, the stator 218, the stator 228, the bearing housing 216, the bearing housing 217, the bearing housing 226, the bearing housing 227, the seal 215, the seal 225, the exhaust manifold 271, and the intake manifold 272. In some embodiments, the bearing housings 216 and 217 are coupled to the stator 218 (e.g., directly connected, or coupled through intermediate components such as flexible members or mounting members). For example, the bearing housings 216 and 217 can be aligned to (e.g., laterally or axially aligned) and fastened to the stator 218 to maintain a radial air gap between the magnet assembly 213 and the stator 218. Similarly, in some embodiments, the bearing housings 226 and 227 are rigidly coupled to the stator 228.

[0095] Translator 210 includes tubular 212, piston 211, seal 262, piston 214, seal 261, and magnet assembly 213, all of which are substantially rigidly coupled to move as a substantially rigid body relative to a fixed assembly along axis 206. Translator 220 includes tubular 222, piston 221, seal 263, piston 224, seal 264, and magnet assembly 223, all of which are substantially rigidly coupled to move as a substantially rigid body along axis 206. In some embodiments, pistons 211 and 221 may include features or components to manage, modify, reduce, or otherwise control thermal expansion of or heat transfer to tubulars 212 and 222, respectively (e.g., spacers with low thermal conductivity, annular tubes that affect the flow of blow-by gas, or both). In some embodiments, magnet assemblies 213 and 223 may be zones of tubulars 212 and 222, respectively. In some embodiments, magnet assemblies 213 and 223 may comprise separate components attached to tubes 212 and 222, respectively. Reaction section 297 is bounded by pistons 211 and 221 (e.g., and also defined by seals 262 and 263) and bore 203 of cylinder 202. Gas springs 298 and 299 are bounded by respective pistons 214 and 224 and respective cylinders 204 and 205. Accordingly, as translators 210 and 220 move along axis 206, the volumes of reaction section 297, gas spring 298, and gas spring 299 expand and contract. In addition, for example, the pressure within those volumes decreases or increases as the volumes increase or decrease, respectively. Each of bearing housings 216, 217, 226, and 227 is configured to provide a gas bearing between itself and a respective translator (e.g., tubes 212 and 222). For example, each of the bearing housings 216, 217, 226, and 227 can be configured to direct pressurized gas to the gas bearing (e.g., via a flow system). In an illustrative example, each of the bearing housings 216, 217, 226, and 227 can be configured to direct pressurized gas at an absolute pressure greater than ambient pressure (e.g., 1 atm at sea level) to the gas bearing so that the bearing gas has sufficient pressure to flow through the gas bearing and into the environment (e.g., directly or via other conduits). In some embodiments, the bearing gas can be pressurized relative to the environment (e.g., about 1 atm), the pressure in the ventilation system (e.g., the gas pressure in the exhaust system that is boosted or may be greater than or less than 1 atm), or any other suitable pressure reference. In some embodiments, the generator assembly 200 is configured for oil-free operation, wherein the bearing housings 216, 217, 226, and 227 form a gas bearing against the translators 210 and 220. Each of the translators 210 and 220 is configured to achieve a position-velocity trajectory.The trajectory may include a top dead center (TDC) position when the corresponding translator is closest to the axial centerline 207 (ie, more inboard) and a bottom dead center (BDC) position when the corresponding translator is farthest from the axial centerline 207 (ie, more outboard).

[0096] The cylinder 202 includes a bore 203 that houses a reaction section 297. The cylinder 202 also includes an illustrative intake vent port 219 and an exhaust vent port 229 that couple the bore 203 to the exterior of the cylinder 202. For example, the intake vent port 229 couples the bore 203 to an intake system, such as its intake manifold 272. In another example, the exhaust vent port 219 couples the bore 203 to an exhaust system, such as its exhaust manifold 271. Intake manifold 272 may be sealed to cylinder block 202, seal 225 (e.g., by extending axially to seal 225), bearing housing 226 (e.g., by extending axially to bearing housing 226), intermediate components, or combinations thereof. Exhaust manifold 271 may be sealed to cylinder block 202, seal 215, bearing housing 216 (e.g., by extending axially to bearing housing 216), intermediate components, or combinations thereof. In some embodiments, as shown, seal 215 comprises a contact seal, which may be constructed of a self-lubricating material (e.g., graphite), a ceramic material, a metal, a plastic, or any other suitable material, or any combination thereof. The seal The seal 215 is fixed relative to the movement of the translator 210 and may be housed within the ring compressor 281 (as shown), the cylinder 202, a dedicated seal holder, or any other suitable component or any combination thereof. In some embodiments, the seal 215 includes a contact seal, a non-contact seal, any other suitable seal, or any combination thereof. In some embodiments, as shown, a translator cooler 270 may be included to provide a pressurized gas flow for cooling the translator 210. In some embodiments, the cooling gas for the translator cooler 270 may be provided by a blower (e.g., of the air intake system), a reservoir of the gas spring system, a gas pump, or a gas pump. The translator 270 may be configured to provide a preferred cooling fluid flow. For example, the translator cooler 270 may provide more cooling fluid flow to one or more surface areas of the translator 210 and less cooling flow to one or more other surface areas of the translator 210, or vice versa. In some embodiments, the translator cooler 270 may be configured to provide substantially uniform cooling. When the intake vent port 229 is not covered by the piston 221 (e.g., the intake port is open) 203, and from the orifice 203 to the exhaust system. However, flow may also occur in the opposite direction, for example, from a blowback or plugging pulse during some time period (e.g., intermittent or transient events).In some embodiments, the radially outer surface of the cylinder 202 is cooled. For example, the radially outer surface of the cylinder 202 may be air cooled (e.g., by a cooling system), fluid cooled (e.g., by a cooling system), or both. In some embodiments, a thermal interface material may be disposed between an air cooling feature (e.g., a fin) and the cylinder 202 to improve thermal conductivity. In some embodiments, the cylinder 202 may include one or more ports disposed between the intake vent port 229 and the exhaust vent port 219, which may be configured to accommodate a sensor (e.g., coupled to a control system), a fuel injector (e.g., coupled to an intake system or a dedicated fuel system), or any other suitable component that may require access to the aperture 203. Along the axis 206, the intake vent port 229 and the exhaust vent port 219 may (but need not be) positioned symmetrically about the center of the cylinder 202. The port location may be referenced to any suitable reference, however, one reference is the location of the front of the port (e.g., closest to the axial centerline 207). The front of the port defines the closed portion of the cycle (e.g., the beginning of compression, the end of expansion, the beginning of ventilation, the end of ventilation). For example, in some embodiments, the exhaust vent port 219 may be relatively closer to the axial centerline 207 than the intake vent port 229. For illustration, the exhaust vent port 219 may open to the reaction section 297 before the intake vent port 229 during the expansion stroke, and the exhaust vent port 219 may close to the reaction section 297 after the intake vent port 229 during the compression stroke. In some embodiments, ventilation techniques other than straight-through scavenging may be used, such as annular flow scavenging or cross-flow scavenging, and accordingly the vent ports may be positioned to be uncovered by only a single piston (e.g., the intake and exhaust vent ports are on the same axial side of the cylinder). In some embodiments, the piston centerline position may be changed during operation to change the relative timing of port opening and closing. For example, although the port position may be spatially fixed on the cylinder 202, the vertex position (e.g., TDC position and BDC position) of the pistons 211 and 221 may be selected to move the TDC centerline (e.g., the midpoint between the TDC positions of the pistons 211 and 221 in either axial direction). In another example, moving the TDC centerline may allow the ventilation behavior to be changed. The timing, relative intensity (e.g., the amplitude of the pressure wave), or both of the port opening and closing of the ventilation behavior may be changed accordingly. In addition, the compression ratio, the expansion ratio, or both may be changed by moving the TDC centerline or the BDC position. For illustration, the TDC centerline may (but not necessarily) coincide axially with the axial centerline 207. The ventilation port position and the piston vertex position may be used to affect the ventilation behavior. In some embodiments, the BDC position of one or both pistons may be changed during operation to change the relative timing of the port opening and closing. For example, a port may remain open for a longer time to affect ventilation.It should be understood that TDC and BDC refer to the corresponding positions where the piston contacts the reaction section (e.g., they correspond to BDC-TDC where the piston contacts the gas spring, respectively). For example, at or near TDC, the reaction section has a minimum volume and the gas spring has a maximum volume. In another example, at or near BDC, the reaction section has a maximum volume and the gas spring has a minimum volume. In some embodiments, the cylinder assembly 254 includes the cylinder 202, the intake manifold 272, the exhaust manifold 271, mounting hardware (e.g., mounting pieces, flexible pieces or other hardware), and any other suitable components that can be installed as a unit. During replacement, installation, removal or inspection, the ring compressors 281 and 282 are coupled to the axial ends of the cylinder 202 for the purpose of maintaining the seals 262 and 263 in the pistons 211 and 221, respectively. For example, during inspection or maintenance, the translators 210 and 220 may be axially positioned so that the ring compressors 281 and 282 are axially aligned with the corresponding seals 262 and 263. In addition, the ring compressors 281 and 282 may be removed with the corresponding pistons 211 and 221 during maintenance or inspection. The ring compressors 281 and 282 may have an inner diameter that is the same or similar to the bore 203 of the cylinder block 202. In some embodiments, the ring compressors 281 and 282 may include two or more sections (e.g., a clamshell design) that are configured to hold the seals 262 and 263 in place during replacement, installation, removal, or inspection. In some embodiments, the ring compressors 281 and 282 may include an integral piece that is configured to hold the seals 262 and 263 during replacement, installation, removal, or inspection. The ring compressors 281 and 282 may be attached to the cylinder block 202 via any suitable means, including but not limited to v-bands, clamps, fasteners, bolts, springs, or any combination thereof.

[0097] In some embodiments, as shown, the cylinders 204 and 205 are closed by respective heads 208 and 209, which may be bolted or otherwise secured to the cylinders 204 and 205 (e.g., to suitable flanges of the cylinders 204 and 205). In some embodiments, the cylinders 204 and 205 include closed ends (e.g., to seal the gas springs 298 and 299, respectively), and do not need to include separate heads. In some embodiments, as shown, the spacers 295 and 296 are arranged to provide axial space (and therefore, volume) to the respective gas springs 298 and 299. The spacers 295 and 296 may be bolted, secured or otherwise secured to the respective cylinders 204 and 205, the respective heads 208 and 209, or both. In some embodiments, the spacers 295 and 296 are configured to act as ring compressors (e.g., during disassembly, inspection, or replacement of the rings). In some embodiments, the spacers 295 and 296 may include two or more sections (e.g., a clamshell design). Cylinders 204 and 205 include corresponding lower pressure ports 230 and 240 for exchanging lower pressure gas (e.g., for exchanging lower pressure gas), and corresponding higher pressure ports 231 and 241 for exchanging higher pressure gas (e.g., for exchanging higher pressure gas). In some embodiments, lower pressure ports 230 and 240 are coupled to the environment, wherein the corresponding gas flow is referred to as "atmospheric ventilation" in this article. In some embodiments, lower pressure ports 230 and 240 are coupled to a low pressure reservoir or source (e.g., regulated atmosphere, or other suitable gas reservoirs or sources above atmospheric pressure). For example, lower pressure ports 230 and 240 may be coupled to corresponding reservoirs 273 and 274, as shown. Reservoirs 273 and 274 may be configured to seal the rear sections of pistons 214 and 224, respectively. As shown, reservoirs 273 and 274 are respectively against bearing housings 217 and 227 and are also respectively against cylinders 204 and 205. The reservoirs 273 and 274 may be sealed against any suitable component of the linear generator, including, for example, a frame, a stator, a gas spring head, any other suitable component, or any combination thereof. The volume of the reservoirs 273 and 274 may be sized to minimize or otherwise limit pressure fluctuations in the gas in the respective rear sections. In some embodiments, filters may be installed at or upstream of the lower pressure ports 230 and 240 to prevent the ingress of particles (e.g., dust or debris), certain molecules (e.g., in some cases, water), or other undesirable components of the gas source. In some embodiments, the cylinders 204 and 205 need not include lower pressure ports 230 and 240, higher pressure ports 231 and 241, or any ports at all.For example, in some embodiments, high pressure ports are not included, and low pressure ports 230 and 240 are included to provide make-up gas to make up for blow-by gas past respective pistons 214 and 224 (e.g., and if applicable, low pressure ports may be included at any suitable location in the respective cylinders or cylinder heads). In some embodiments, driver sections 250 and 258 may include features for removing energy from the generator system to prevent damage or failure (e.g., over-pressurization of gas springs 298 or 299, loss of seal of gas springs 298 or 299). Fig.12 Additional details of such features are described in the context of . For example, either or both of cylinders 204 and 205 may include grooves (e.g., "scalloped shapes") configured to allow higher pressure gas to leak around seals (e.g., rings) in the event of piston 214 and 224 overtravel, thus causing the gas spring to lose pressure and energy. In another example, a pressure relief valve may be included that is coupled to the gas spring to cause the gas spring to release energy (e.g., gas) in the event that pressure exceeds a design threshold.

[0098] Stator 218, magnet assembly 213, tube 212, and bearing housings 216 and 217 form a linear electromagnetic machine (LEM) 256. Similarly, stator 228, magnet assembly 223, tube 222, and bearing housings 226 and 228 form LEM 252. In addition, the LEM may optionally include one or more pistons. For example, the LEM may be defined as including stator 218, translator 210, and bearing housings 216 and 217. In another example, the LEM may be defined as including stator 228, translator 220, and bearing housings 226 and 227. The LEM includes a stationary assembly (e.g., a stator and a bearing housing) and a translating assembly (e.g., a translator) constrained to move along an axis, wherein the stator is capable of exerting an electromagnetic force on the translator to cause and / or achieve motion along the axis. The bearing housing of the LEM may (but need not) be attached to the stator. For example, the bearing housing may be coupled to the stator, the structural frame, the cylinder block, or any combination thereof, directly or through an intermediate component. The stators 218 and 228 may include multiple phase windings that form multiple phases. The current in each of the phases may be controlled in time by a control system (e.g., which may include corresponding power electronics and processing equipment) to affect the positioning of the translators 210 and 220, the movement of the translators 210 and 220, the work interaction with the translators 210 and 220, or any combination thereof. In some embodiments, the magnet assemblies 213 and 223 include permanent magnets arranged in an array (e.g., alternating north and south poles). Because the translators 210 and 220 move as a substantially rigid assembly, the electromagnetic force applied to the respective magnet assemblies 213 and 223 accelerates and decelerates the translators 210 and 220. In some embodiments, the stators 218 and 228 may be air cooled (e.g., by an air cooling system), liquid cooled (e.g., by a liquid cooling system), or both. In some embodiments, the stators 218 and 228 are arranged around the respective translators 210 and 220 or their respective magnet assemblies 213 and 223 (e.g., the motor air gap is an arcuate shape with a thickness configuration). For example, the stators 218 and 228 may extend completely around (e.g., azimuthally 360 degrees around) or partially around (e.g., azimuthally arranged segments and azimuthally arranged gaps between windings with phases) the respective translators 210 and 220. In some embodiments, the stators 218 and 228 are arranged axially along the respective translators 210 and 220 or their respective magnet assemblies 213 and 223. For example, the magnet assemblies 213 and 223 may include flat magnet segments, and the stators 218 and 228 may include flat surfaces corresponding to the magnet segments (e.g., the motor air gap is a plane with a thickness configuration). In some embodiments, stators 218 and 228 extend axially along respective translators 210 and 220 or their respective magnet assemblies 213 and 223 .

[0099] In some embodiments, the generator assembly 200 includes one or more features for protecting the components of the generator assembly 200 from damage due to mechanical failure, control failure, component failure, operation under extreme conditions, or a combination thereof. As shown, the limit stops 290 and 291 are arranged to convert the kinetic energy from the respective translators 210 and 220 into deformation by contacting the respective pistons 214 and 224 in the event of translator overtravel. For example, one or both of the stators 218 and 228 may include one or more features for protecting the generator assembly 200. In some embodiments, one or both of the stators 218 and 228 include one or more features (e.g., limit stops, mechanical springs, pneumatic pistons) configured to convert the kinetic energy of the translator into sound, heat, solid deformation, or a combination thereof, thereby slowing, stopping, or redirecting the movement of the translator. For example, the limit stops may be configured to undergo plastic deformation (e.g., bend, press, wrinkle, stamp, or otherwise deform) after contacting the translator to convert the kinetic energy of the translator. In some embodiments, one or more limit stops may be disposed at either or both of the driver sections 250 and 258. In some embodiments, limit stops are included as part of other components of the generator assembly 200, such as the driver sections 250 and 258. In some embodiments, limit stops are located at each end of the cylinder 202 near the BDC. The limit stops may be attached to the structural frame at any suitable location directly or with intermediate components, attached to the cylinder (e.g., cylinders 203, 204, 205, or a combination thereof) at any suitable location directly or with intermediate components, attached to the stator at any suitable location directly or with intermediate components, or a combination thereof. In some embodiments, the generator assembly 200 may include a plurality of components for attaching to the structural frame (e.g., such as Figure 53-57 For example, cylinder assembly 254, driver sections 250 and 258, and LEMs 252 and 256 may include one or more features or components for attachment to a structural frame, one or more features or components for alignment to a structural frame, one or more components or features for aligning a structural frame to another assembly (e.g., LEM 252 to LEM 256, cylinder assembly 254 to LEM), or any combination thereof. In some embodiments, features or components for attaching a portion of generator assembly 200 to a structural frame may provide compliance in one direction (e.g., axial, lateral, or radial), and stiffness in a different direction (e.g., axially stiff while radially compliant) to account for changes during operation.

[0100] Figure 33 is a block diagram of an illustrative linear generator 300 including a control system 310 for controlling the operation of a generator assembly 350 according to some embodiments of the present disclosure. The generator assembly 350 may include one or more stators, each of which includes a plurality of windings corresponding to a plurality of phases (e.g., each phase includes one or more windings). For example, the stator may include three or more phases, which may electromagnetically interact with the translator to apply force to the translator. For example, the phases may apply force on the translator in the same direction of motion (e.g., motor drive) or in opposite directions of motion (e.g., braking or generating electricity) (or a combination thereof) during a stroke or cycle (alternatingly). The flow of current (e.g., direction and magnitude) in each winding and thus each phase (e.g., even if more than one winding is included in a phase) may be controlled by the control system 310 and supplied / received using the power subsystem 322.

[0101] The control system 310 may include a processing device 312, a memory 314, one or more communication interfaces 316, one or more user interfaces 318, a sensor interface 320, a power subsystem 322, any other suitable components or modules not shown, or any combination thereof. The control system 310 may be implemented at least in part in one or more computers, embedded systems, terminals, control stations, handheld devices, modules, any other suitable interface devices, or any combination thereof. In some embodiments, the components of the control system 310 may be communicatively coupled via one or more communication buses 324, such as Figure 3 shown.

[0102] In some embodiments, control system 310 is configured to control the trajectory of the translator, control power output, control energy storage, control operating conditions, respond to electrical loads, manage the provision of intake air to the cylinder, manage the removal of exhaust from the cylinder, ensure safe operation (e.g., perform diagnostics and detect faults), any other suitable function, or any suitable combination thereof (e.g., all of the foregoing).

[0103] In some embodiments, the control system 310 receives information from one or more sensors 330, user input (e.g., at the user interface 318), a reference database (e.g., a lookup table stored in the memory 314), any other source, or any combination thereof, and determines a corresponding control response. For example, the control system 310 may receive position information about the translator and stator of the generator assembly 350 from the sensor 330 along with the desired force information, and determine the current value of one or more phases of the electromagnetic machine. In some embodiments, the control system 310 controls the current in each phase of the stator. In some embodiments, the control system 310 controls the current in each phase based on position information (e.g., axial position, axial velocity, axial acceleration), magnetic flux information, motor constant information (e.g., force constant, back EMF), any other suitable information, or any combination thereof. The control system 310 may control the magnitude of the current in each phase, the direction of the current flow in each phase, or both. The control system 310 may control the commutation of the current in multiple phases.

[0104] The processing device 312 may include a processor (e.g., a central processing unit), a cache, a random access memory (RAM), a read-only memory (ROM), any other suitable component, or any combination thereof that can process information about the multiphase electromagnetic machine 350. The memory 314 may include any suitable volatile or non-volatile memory, which may include, for example, a random access memory (RAM), a read-only memory (ROM), a flash memory, a hard disk, any other suitable memory, or any combination thereof. The information stored in the memory 314 may be accessed by the processing device 312 via the communication bus 324. For example, computer-readable program instructions (e.g., for implementing the techniques disclosed herein) stored in the memory 314 may be accessed and executed by the processing device 312. In some embodiments, the memory 314 includes a non-transitory computer-readable medium for storing computer-executable instructions that cause the processing device 312 (e.g., a processing device of a suitable computing system) to perform a method for controlling a generator assembly, an intake system, an exhaust system, a cooling system, a bearing system, a gas spring system, any other suitable system, or any combination thereof. For example, memory 314 may include computer-executable instructions for implementing any of the control techniques described herein.

[0105] In some embodiments, the communication interface 316 includes a wired connection (e.g., using IEEE 802.3 Ethernet, or Universal Serial Bus interface protocols), a wireless coupling (e.g., using IEEE 802.11 "Wi-Fi", Bluetooth, or via a cellular network), an optical coupling, an inductive coupling, any other suitable coupling, or any combination thereof, for communicating with one or more systems external to the control system 310. For example, the communication interface 316 may include a USB port configured to accept a flash memory drive. In another example, the communication interface 316 may include an Ethernet port configured to allow communication with one or more devices, networks, or both. In another example, the communication interface 316 may include a transceiver configured to communicate over a cellular network using any suitable standard.

[0106] In some embodiments, the user interface 318 includes a wired connection (e.g., using IEEE 802.3 Ethernet, or a universal serial bus interface, a tip-ring-seal RCA type connection), a wireless coupling (e.g., using IEEE 802.11 "Wi-Fi", infrared, Bluetooth, or via a cellular network), an optical coupling, an inductive coupling, any other suitable coupling, or any combination thereof, for communicating with one or more of the user interface devices 326. The user interface device 326 may include a display, a keyboard, a mouse, an audio device, any other suitable user interface device, or any combination thereof. For example, the display may include a display screen, such as a cathode ray tube screen, a liquid crystal display screen, a light emitting diode display screen, a plasma display screen, any other suitable display screen that can provide graphics, text, images, or other visual data to a user, or any combination of screens thereof. In addition, the display may include a touch screen that can provide tactile interaction by, for example, providing one or more soft commands on the display screen. In another example, the user interface device 326 may include a keyboard, such as a QWERTY keyboard, a numeric keypad, any other suitable collection of hard command buttons, or any combination thereof. In another example, the user interface device 326 may include a mouse or any other suitable pointing device that can control a cursor or icon on a graphical user interface displayed on a display screen. In another example, the user interface device 326 may include an audio device, such as a microphone, a speaker, a headset, any other suitable device for providing and / or receiving an audio signal, or any combination thereof. In some embodiments, it is not necessary to include a user interface 318, a user interface device 326, or both (e.g., the control system 310 does not need to receive user input, nor does it need to provide output to the user). In some embodiments, the user interface device 326 includes a computing device with which the user can interact. For example, the user interface device 326 may include a computer with a touch screen, and a software application (e.g., a web portal hosted by an application server or other host system) may generate a display and process user input. In another example, the user interface device 326 may be coupled to the communication interface 316 (e.g., using a network-based application implemented via a network connection).

[0107] In some embodiments, the sensor interface 320 includes a power supply (e.g., for powering the sensor 330), a signal conditioner, a signal preprocessor, any other suitable component, or any combination thereof. For example, the sensor interface 320 may include one or more filters (e.g., analog and / or digital), amplifiers, samplers, and analog / digital converters for conditioning and preprocessing signals from the sensor 330. In some embodiments, the sensor interface 320 communicates with the sensor 330 via a communication coupling 332, which may be a wired connection (e.g., using IEEE 802.3 Ethernet, or a universal serial bus interface), a wireless coupling (e.g., using IEEE 802.11 "Wi-Fi" or Bluetooth), an optical coupling, an inductive coupling, any other suitable coupling, or any combination thereof.

[0108] Sensor 330 may include any suitable type of sensor that may be configured to sense any suitable property or aspect of generator assembly 350, any other system, or any combination thereof. In some embodiments, sensor 330 includes a linear encoder, a rotary encoder, or both, configured to sense the relative positioning between the translator and the stator of generator assembly 350. In some embodiments, sensor 330 includes an accelerometer configured to sense the acceleration of the translator relative to a fixed stator, vibration of a nominally static component, or any other suitable acceleration. In some embodiments, sensor 330 includes a camera configured to capture an image of the translator relative to the stator of generator assembly 350 (e.g., time-lapse imaging). In some embodiments, sensor 330 includes one or more current sensors (e.g., coupled to the phase of the stator of generator assembly 350), one or more voltage sensors (e.g., coupled to the phase of the stator of generator assembly 350), or both, configured to sense the voltage, current, work output and / or input (e.g., current multiplied by voltage), any other suitable electrical property of the linear generator, or any combination thereof. In some embodiments, sensor 330 includes one or more temperature sensors, such as thermocouples, thermistors, resistance temperature detectors (RTDs), any other suitable sensors for detecting temperature, or any combination thereof. For example, sensor 330 may include a thermocouple arranged to measure the temperature of a permanent magnet, a winding, a power subsystem component such as a transistor, a cylinder, a bearing housing, a gas (e.g., an intake or exhaust), or any other component or fluid of the linear generator. In some embodiments, control system 310 is configured to control the axial position of a translator of generator assembly 350 during non-operational events (e.g., when not generating electricity). For example, in some embodiments, control system 310 is configured to move the translator axially outward and engage a locking mechanism (not shown) to axially lock the translator in place during maintenance, inspection, or removal, installation, or replacement of components in generator assembly 350.

[0109] In some embodiments, sensor 330 may be included in control system 310. In some embodiments, sensor 330 may be partially or fully integrated into generator assembly 350 (e.g., an encoder strip attached to a translator). In some embodiments, sensor 330, sensor interface 320, or both may be removed from control system 310, external to control system 310, optionally omitted from control system 310, optionally installed with control system 310, or otherwise not included in control system 310. For example, sensor 330 may include a piezoelectric pressure sensor with control circuitry separate from control system 310. In addition to this example, the control circuitry may optionally be integrated into control system 310.

[0110] In some embodiments, the power subsystem 322 includes control circuitry, power electronics, an electrical load (e.g., for dissipating electrical energy to heat via a resistive load bank), a ground (e.g., a chassis or ground), a terminal board, a power storage device (e.g., a battery, a capacitor), an electrical bus for delivering power, an insulated gate bipolar transistor (IGBT), a mechanical relay, a solid-state relay, a power diode, a thyristor, a metal oxide semiconductor field effect transistor (MOSFET), any other suitable transistor, a switch, a contactor, a fuse, a pulse width modulation controller, a digital / analog controller, any other suitable electronic component, any other suitable controller, or any combination thereof. The power subsystem 322 may receive control signals regarding the generator assembly 350 from the processing device 312 via the communication bus 324. For example, the power subsystem 322 may include a plurality of IGBTs coupled to respective phase conductors of a plurality of phases of a stator via a power coupling 352. To illustrate, the IGBTs may be coupled to high and low bus voltage lines, as well as the windings of the phases, which may be coupled to a wye-shaped three-phase circuit neutral point. In some embodiments, the power coupling 352 includes one or more cables, wires, connectors, or a combination thereof. For example, each phase of the stator may be coupled to a corresponding terminal of the power subsystem 322 via a corresponding cable. In some embodiments, the power subsystem 322 includes virtual phases that may accommodate current flow but do not correspond to any phase of the stator of the generator assembly 350. In some embodiments, the power subsystem 322 includes a grid tie inverter (GTI) configured to manage power interaction between the linear generator 300 and the power grid. For example, in some embodiments, the power subsystem 322 may include a DC bus having a DC voltage managed by the GTI. In some embodiments, the power subsystem 322 includes batteries, capacitors, or both for storing electrical energy from the linear generator system, an external source (e.g., a power grid), or both, and for discharging the stored electrical energy to support operation of the linear generator system (e.g., for startup, for outputting a load). In an illustrative example, the power subsystem 322 may include or be similar to Figure 1 The electrical system 105. Accordingly, reference Figure 1 , the control system 104 and the electrical system 105 may be combined.

[0111] although Figure 3 Although not shown in the figure, the control system 310 may include one or more system interfaces for controlling, monitoring, receiving information from, or a combination thereof, any suitable system. For example, the control system may include a motor controller for controlling a boost blower motor. In another example, the control system may include a motor controller for controlling a fan of a cooling system.

[0112] In an illustrative example, control system 310 may be configured to control the force interaction between the translator and the stator. Force may be applied to the translator by controlling current (e.g., magnitude and direction) in one or more phases that electromagnetically interact with the translator. In some embodiments, the desired force is determined based on position information, velocity information, acceleration information, or a combination thereof, and control system 310 applies current to one or more phases to achieve the desired force on the translator (e.g., the achieved force may be, but need not be, equal to the desired force). Encoders may be used to determine the position of the translator relative to the stator, the velocity of the translator (e.g., by calculating a suitable time derivative or a second time derivative using any suitable analytical or numerical differentiation technique), the acceleration of the translator (e.g., by calculating a time derivative using any suitable analytical or numerical differentiation technique), any other suitable information, or any combination thereof.

[0113] In another illustrative example, the control system 310 may be configured to control the storage, accumulation, and conversion of energy in the gas spring during operation of the linear generator system (e.g., during cycling of the generator assembly). In some embodiments, the operation of the gas spring may be adjustable (e.g., the amount of stored energy, the maximum pressure, or the minimum pressure may be adjustable). In some embodiments, the low pressure port, the high pressure port, or both may be used to control a characteristic of the gas spring. For example, the low pressure port, the high pressure port, or both may be used to control the amount, temperature, pressure, any other suitable characteristic, and / or any combination thereof of the gas in the gas spring. In some embodiments, adjusting any of the aforementioned characteristics and, therefore, the amount of mass in the gas spring may change the effective spring constant of the gas spring. The effective spring constant may depend on, for example, the gas temperature, the gas pressure, the gas composition, a quantity derived therefrom (e.g., density), or a combination thereof. For example, to achieve a change in stored energy, the effective spring constant, the displacement, or both may be changed. Two illustrative approaches include: (1) for a fixed effective spring constant (e.g., which may still include a known position dependency), the displacement may be used to control the amount of energy stored in the gas spring, and (2) for a fixed displacement (e.g., fixed TDC and BDC positions), the effective spring constant may be used to control the amount of energy stored in the gas spring. To illustrate, in some embodiments, the control system 310 is configured to control the axial displacement of the translator to control the storage of energy in the gas spring. For example, the control system 310 may control the BDC position of the translator during a stroke (i.e., the outer vertex position as the gas spring's TDC) to store a desired amount of energy in the respective gas spring (e.g., at least a sufficient amount of energy to perform a subsequent stroke without requiring a net electrical input during the subsequent stroke). Furthermore, in some cases, a more outer BDC position may correspond to relatively greater energy being stored in the gas spring (e.g., making it possible to generate a net electrical output from the generator assembly 350 to the power subsystem 322 during a subsequent stroke while providing sufficient energy to perform a subsequent stroke). In addition, the control system 310 can determine or estimate the energy required to perform the subsequent stroke, and can control the storage of energy in the gas spring to store at least the required energy during the expansion stroke (i.e., during the expansion of the reaction section and the simultaneous compression of the gas spring). In some embodiments, one or more parameters associated with the auxiliary system are adjusted to achieve flow into or out of the gas spring. For example, the gas spring supply tank pressure, regulator pressure, or other parameters can be adjusted to achieve gas flow to a low pressure port (e.g., into the gas spring) or a high pressure port (e.g., out of the gas spring) of the gas spring system.

[0114] In some embodiments, the geometry of the gas spring may be adjusted to achieve desirable operation. For example, the volume of the gas spring may be increased or decreased by controlling the gas exchange with the gas spring via the low pressure port, the high pressure port, or both, and the characteristics of the gas flowing therein. In some embodiments, the dead volume within the cylinder may be adjusted to change the spring constant of the gas spring (e.g., another form of change that affects the position or volume of the gas spring). It should be understood that any of the foregoing controls and adjustments of the gas spring therein may enable control of the amount of energy stored by the gas spring during the expansion stroke of the generator assembly. It will also be understood that the foregoing control of the characteristics of the gas spring may also enable variability in the frequency of the cycles of the generator assembly.

[0115] In some embodiments, the exhaust system may be tuned along with the intake system to affect the ventilation process. In some embodiments, one or more intake runners and one or more exhaust tuning ducts may be configured to achieve a ventilation process with specific ventilation characteristics. For example, one or more intake runners and one or more exhaust tuning ducts may include a predetermined length, diameter, or both to generate the desired ventilation characteristics. In an illustrative example, the desired ventilation characteristics may include a transient pressure configuration in the intake manifold and a transient pressure configuration in the exhaust manifold that causes intake air to be drawn into the holes (e.g., high intake manifold pressure occurs when an exhaust suction wave occurs). In another illustrative example, the desired ventilation characteristics may include a blocking pulse from the exhaust system that limits, reduces, or prevents large amounts of blow-through of unreacted fuel in the exhaust (e.g., preventing increases of more than one, ten, one hundred, or one thousand parts per million of fuel in the exhaust). The desired ventilation characteristics may allow for lower boost pressures (e.g., caused by Figure 7 boost blower 704 generation), lower blower power requirement, lower emissions, higher indicated power, higher indicated efficiency, lower fuel consumption, or a combination thereof.

[0116] In some embodiments, the exhaust system, intake system, and generator assembly may be configured to exhibit desired ventilation characteristics. For example, the axial arrangement and design of the intake and exhaust ventilation ports (e.g., the location of the ventilation ports along the axis of the cylinder), the design of the intake system (e.g., the size and shape of the intake manifold or the type of fuel injection strategy), the design of the exhaust system (e.g., the size and shape of the exhaust manifold or the length of the tuning duct), the intake boost pressure, along with other suitable system properties and operating modes, may affect the ventilation characteristics. In some embodiments, the desired ventilation and exhaust characteristics may be achieved by configuring various geometric properties, such as: the open and closed position of the intake ventilation port, the intake runner length and cross-section, the open and closed position of the exhaust ventilation port, the tuning duct length and cross-section, the exhaust runner length and cross-section, the manifold volume and length scale, or any combination thereof. It should be understood that the opening or closing of the port is referenced in the context of its coupling to the compression / expansion volume (e.g., in front of the seal, such as the forward portion of the piston). For example, a port may be closed by a piston but still open to a volume behind a piston seal proximate to the translator tubing (e.g., post-reaction section). In another example, port opening or closing involves a path for gas exchange between the corresponding manifold / plenum and the volume of the cylinder bore between the intake and exhaust ports. To illustrate, the compression / reaction section volume "V" is given by the following formula:

[0117] V=A Cyl (x ip +x ep )

[0118] Where "Acyl" is the nominal cross-sectional area of ​​the hole, "x ip " is the axial position of the intake piston surface, "x ep ” is the axial position of the exhaust piston, where the axial position is measured from the centerline of the cylinder (e.g., Figure 2axial centerline 207 of the piston). In some cases, the volume behind the piston may also undergo compression and expansion. Ventilation characteristics such as the amplitude of the venting pulse, the blocking pulse, and the suction wave and their timing during the ventilation process may be affected by the geometric properties of the system. In addition, the operating properties can be configured to cause the desired ventilation characteristics, and may include the intake pressure generated by the booster blower, the gas pressure in the hole when the exhaust ventilation port is uncovered, the equivalence ratio, the top dead center (TDC) position of the piston face when the reaction cylinder volume is at a minimum during the operating cycle (e.g., close to the center), the bottom dead center (BDC) position of the piston face when the reaction cylinder volume is at a maximum during the operating cycle (e.g., facing away from the center of the cylinder), the fuel pressure, and the frequency of the translator reciprocation (e.g., the inverse of the cycle time). For example, the TDC and BDC positions can affect the timing and duration of the ventilation process. In another example, the equivalence ratio can affect the amplitude of the venting pulse and the wave characteristics in the tuning duct. In some embodiments, the TDC position of the piston face can be adjusted relative to the centerline to affect ventilation, the BDC position can be adjusted relative to the port to affect ventilation, or both. For example, for a relative piston configuration, the TDC and BDC positions of each translator can be adjusted to affect ventilation or other engine performance.

[0119] Figure 4 A portion of an illustrative generator assembly 400 is shown having reaction section pistons 410 and 420 at respective axial positions according to some embodiments of the present disclosure. Intake piston 410 and exhaust piston 420 move within a bore of cylinder 405 along axis 406. The axial positions of reaction section pistons 410 and 420 may be referenced to any suitable reference including, for example, axial centerline 407. Intake port 415 and exhaust port 425 are axially arranged at respective positions of cylinder 405. The axial positions of intake port 415 and exhaust port 425 may, but need not be, equidistant from axial centerline 407. For example, as shown, exhaust port 425 is closer to axial centerline 407 than intake port 415.

[0120] Panel 490 shows an illustrative start of ventilation, where intake piston 410 with seal 411 is axially positioned inboard of intake port 415 (e.g., intake port 415 is only open to volume 401 of cylinder 405). Panel 491 shows exhaust piston 420 with seal 421 being axially positioned just within the axial range of exhaust port 425 (e.g., exhaust port 425 is partially open to volume 401 of cylinder 405).

[0121] Panel 491 shows intake piston 410 with seal 411 positioned axially outboard of intake port 415 (e.g., intake port 415 opens to volume 402 of cylinder 405). Panel 491 shows exhaust piston 420 with seal 421 positioned axially outboard of exhaust port 425 (e.g., exhaust port 425 opens to volume 401 of cylinder 405).

[0122] Panel 492 shows that near the end of ventilation, intake piston 410 with seal 411 is axially positioned at the open / closed threshold of intake port 415 (e.g., intake port 415 is closed to volume 401 of cylinder 405). Panel 492 shows exhaust piston 420 with seal 421 axially positioned toward the middle of exhaust port 425 because exhaust port 425 is axially farther inward than intake port 415.

[0123] Panel 493 shows that at the end of ventilation and the beginning of compression, the intake piston 410 with seal 411 is positioned axially inboard of the intake port 415 (e.g., the intake port 415 is closed to the volume 401 of the cylinder 405). Panel 493 shows that the exhaust piston 420 with seal 421 is positioned axially inboard of the exhaust port 425. Panel 493 shows that both the intake port 415 and the exhaust port 425 are closed to the volume 401.

[0124] Figure 5A portion of an illustrative generator assembly 500 with lean pre-positioning is shown according to some embodiments of the present disclosure. Lean pre-positioning is a process in which a relatively lean intake air "leads" a relatively rich intake air during the ventilation process so as to reduce blow-through, reduce the residual mass fraction (RMF), or both. For example, during the ventilation process, it may be necessary to make the portion of the small amount of intake air entering the cylinder have a relatively lean portion at the beginning and end. The relatively lean portion reduces the tendency of fuel to blow through into the exhaust system near the end of the ventilation process. For example, this non-uniform intake concentration configuration can allow a lower amount of residual exhaust to be trapped while limiting or eliminating the flow of fuel passing through. In some embodiments, control of the piston position in time can allow control of the ventilation behavior. For example, synchronization of the relative piston position can allow the timing of port opening and closing to generate the desired ventilation behavior (e.g., venting pulses, segment pulses, blocking pulses, or other behaviors). In another example, lean pre-positioning can allow for greater boost pressure and reduced RMF (e.g., thereby increasing power density, compression ratio, other operating performance, or a combination thereof). Panel 590 shows a reaction section piston 510 (e.g., an intake piston) with seal 511 and a reaction section piston 520 (e.g., an exhaust piston) with seal 521 at the end of the ventilation process. The intake includes a fuel and air mixture, as shown, which enters volume 501 of cylinder 505 from intake port 515. The intake displaces the exhaust formed during the reaction of the gas in the previous cycle. The displaced exhaust exits volume 501 via exhaust port 525. At the end of the ventilation process, some exhaust remains in volume 501. This remaining gas is called residual gas, which can be characterized by the considered RMF of the intake trapped at the end of the ventilation process. In some embodiments, it is necessary to reduce the RMF. Panel 591 shows the end of ventilation with lean pre-flow applied to generator assembly 500 (e.g., and the beginning of compression). Residual gas, lean pre-flow, and post-flow intake are trapped in volume 501. The lean pre-flow and post-flow intake are collectively referred to as "intake". Lean pre-staging allows the gas in volume 501 to be axially stratified to prevent post-intake fuel from exiting exhaust port 525 during ventilation. In the illustrative example, Figure 16-17 The configuration shown in can be used to achieve lean gas pre-positioning.

[0125] In some embodiments, the injector may be configured to inject gaseous fuel, liquid fuel, or both. For example, the injector may be configured to inject natural gas, methane, propane, biogas, hydrogen, or other suitable gaseous fuels into the intake system. In some embodiments, for example, the injector may include a carburetor-type injector configured to inject fuel at a relatively low supply pressure. The injector may inject fuel at a constant rate, at a variable rate, at a rate depending on the local intake pressure, at a certain frequency (e.g., pulse control), at any other suitable schedule, or any combination thereof. For example, the injector may exhibit pulse operation, continuous operation, pulse operation with piston position timing, any other suitable operating mode, or any combination thereof. The injector may generate or experience any suitable flow properties (e.g., average or local flow rate, pressure drop, or other properties), and may be controlled using any suitable control technology based on any suitable flow properties. For example, the injector may be driven by pulse width modulation (PWM), pulse density modulation (PDM), DC pulses (e.g., from an injector drive), any other suitable actuation technology, or any combination thereof. In another example, the drive signal to the injector may be controlled based on fuel flow rate, fuel pressure, boost pressure, pressure within a flow path, pressure within a cylinder, pressure drop (e.g., across an injector or other suitable component), exhaust composition, load requirements (e.g., linear generator electrical output), reaction timing (e.g., boost, hold, or delay timing), translator position (e.g., related to port opening and closing), ventilation characteristics (e.g., timing and amplitude of pressure waves during ventilation), any other suitable operating parameter, or any combination thereof.

[0126] The above description is illustrative only, and it will be appreciated that any suitable geometrical, operational, or other system properties may be configured to affect ventilation characteristics.

[0127] Figure 6 Two cross-sectional views of an illustrative translator with a reservoir are shown in accordance with some embodiments of the present disclosure. For example, panels 600 and 650 show Figure 2 262 and an illustrative enlarged section behind the seal 263. In another example, Figure 2 The pistons 211 and 221 may include Figure 6 An annulus, diffuser, reservoir, restriction, or a combination thereof as described in the context of.

[0128] Panel 600 shows a translator including a tube 622, a piston 620, a seal 621 (e.g., a piston ring), and a collar 610, all of which are substantially rigidly coupled to move as a substantially rigid body along the axis of a cylinder 602. Cylinder 602 includes a bore 603 configured to accommodate a reaction section 697. As shown, piston 620 is attached to collar 610 using fasteners 613, and collar 610 is attached to tube 622 using fasteners 614. Panel 650 shows a translator including a tube 672, a piston 670, a seal 671 (e.g., a piston ring), and a collar 660, all of which are substantially rigidly coupled to move as a substantially rigid body along the axis of a cylinder 652. As shown, piston 670 is attached to collar 660 using fasteners 663, and collar 660 is attached to tube 672 using fasteners 664.

[0129] As shown in panel 600, collar 610 forms a reservoir 606 with holes 603, wherein reservoir 606 affects the flow of the blow-by gas bearing. Collar 610 also forms a restriction 612 (e.g., a labyrinth restriction as shown) with holes 603, wherein restriction 612 affects the flow of gas leaving reservoir 606. For example, if a leak path is open in seal 621, relatively hot gas from reaction section 697 may be ejected along holes 603 and may cause axial asymmetric thermal deformation of tube 622 (e.g., in approximately the same azimuthal position as the leak path). Collar 610 is configured to reduce the velocity of the leaking gas (e.g., blow-by gas) and azimuthally distribute the gas to reduce asymmetric thermal deformation downstream of the collar (e.g., to the translator tube). As shown in panel 600, piston 620 includes diffuser 624. Diffuser 624 may optionally be included to improve the effectiveness of reservoir 606 by reducing the rate of leaking gas before reaching reservoir 606. Reservoir 606 includes a volume that extends azimuthally around annulus 610 and allows for the collection and azimuthal distribution of leaking gas. Restriction 612 restricts the flow of gas out of reservoir 606 and allows for the collection of leaking gas in reservoir 606. As shown in panel 600, restriction 612 includes a labyrinth restriction that extends azimuthally around annulus 610 and provides a certain suitable axial pressure drop and azimuthal distribution with each groove of the labyrinth.

[0130] As shown in panel 650, annulus 660 forms a reservoir 656 with holes 603, wherein reservoir 656 affects the flow of blow-by gas bearings. Annulus 660 includes a restriction 662, which includes a ring that restricts the flow of gas leaving reservoir 656 and along tubing 672. In some embodiments, annular restrictions such as restriction 662 provide an improved thermal path to hole 603 of cylinder 602. In some embodiments, one or more annular restrictions may be included to provide a larger pressure drop, but the addition of annular restrictions may increase friction losses. In some embodiments, restriction 662 may be configured not to be excited by the leaking gas and may have limited or zero contact with hole 603. In some embodiments, restriction 662 may be configured not to contact hole 603 during normal operation. In some embodiments, restriction 662 may include features configured to introduce vortices (e.g., azimuth distribution) downstream of annulus 660 to further reduce asymmetric thermal deformation of tubing 672. In some embodiments, restriction 662 may include one or more gear-shaped teeth and grooves azimuthally surrounding collar 660 to further distribute flow downstream of the collar. For example, the collar may include a labyrinth restriction (e.g., restriction 612), a contacting or non-contacting ring restriction (e.g., restriction 662), a restriction having features that induce vortices downstream of the one or more gear-shaped teeth and grooves, any other suitable restriction, or any combination thereof.

[0131] Although shown as separate components, piston 620 and collar 610 (e.g., or piston 670 and collar 660) can be a single component (e.g., the piston can form a reservoir with a cylinder bore), separate components (e.g., as shown), or a collection of two or more components (e.g., a multi-component collar). In some embodiments, collar 610 can include a diffuser, a reservoir, and a restriction, or any combination thereof. In some embodiments, piston 620 can include a diffuser, a reservoir, and a restriction, or any combination thereof. The collar or collar-like section of the piston can include any suitable material, such as metal, ceramic, plastic, composite, any other suitable material, or any combination thereof. In some embodiments, piston 620 includes a high temperature alloy metal (e.g., Inconel), and collar 610 includes a different type of metal. In some embodiments, collar 610 includes a metal having a thermal expansion coefficient similar to fasteners 613 and 614.

[0132] The intake system is configured to introduce reactants into the cylinder of the generator assembly. For example, the intake system may be configured to provide a controlled air and fuel mixture to the cylinder during ventilation (e.g., the entry and exhaust of gas from the holes of the cylinder). In another example, the intake system may be configured to provide a controlled amount of air (e.g., via ventilation) and a controlled amount of fuel (e.g., via direct injection, near port injection or other suitable fuel injection types) to the cylinder. In another example, the intake system may be configured to provide a controlled amount of air / fuel mixture to the cylinder. In another example, the intake system may be configured to provide a controlled amount of air to the cylinder and separately provide a controlled amount of fuel to the cylinder. The intake system may be configured to provide reactants under suitable conditions such as suitable pressure, temperature, rate, composition (e.g., equivalence ratio, humidity, residual trapped exhaust, exhaust gas recirculation content) or any other suitable properties or any combination thereof. Figure 7-17 An illustrative air intake system and components thereof are shown in accordance with the present disclosure. It should be understood that while the subsequent description is primarily in terms of air, the present disclosure may be applied to any intake air (e.g., dirty air, oxygen, other oxidants, inert components, or other gases) in accordance with the present disclosure. It will also be understood that the present disclosure may be applied to any suitable fuel including gaseous fuels, liquid fuels, atomized fuels, slurry fuels, any other suitable fuels, or any suitable combination thereof.

[0133] Figure 7 A system diagram of an illustrative air intake system 700 is shown according to some embodiments of the present disclosure. Air intake system 700 optionally includes, for example, a filter 702, a boost blower 704, an intercooler 706, a manifold system 710, corresponding lines (e.g., flow passages and fittings), sensors, any other suitable components, or any suitable combination thereof.

[0134] The filter 702 is configured to restrict one or more components in the intake air supply from entering the rest of the intake system 700 and the corresponding generator assembly. As shown, the filter 702 is arranged upstream of the boost blower 704, the intercooler 706, and the manifold system 710. In some embodiments, the filter 702 is located downstream of the intercooler 706 and upstream of the manifold system 710. In some embodiments, the filter 702 is located downstream of the boost blower 704 or any other suitable location in the intake system. In some embodiments, multiple filters 702 may be included, which are located at various locations in the intake system. For example, the filter 702 may be configured to filter particles, dust, particulate matter, debris, moisture (e.g., a dehumidification or coalescing filter) or other materials that may be in the intake air supply. The filter 702 may include any suitable number of filters (e.g., one or more) arranged in any suitable configuration (e.g., in series or in parallel, at one or more locations along the intake system). For example, multiple filters can be used in series, in parallel, or in a combination of series and parallel.

[0135] The booster blower 704 is configured to increase the pressure of the air entering, the speed of the air entering, or both. For example, the booster blower 704 can allow the air entering during the ventilation process (e.g., during the direct current scavenging process) to more thoroughly purge the exhaust from the cylinder. In another example, the booster blower 704 can achieve a higher pressure in the cylinder when the port is closed, thereby increasing the power density of the generator system (e.g., by increasing the trapped pressure, reducing the residual gas trapped, or both). The booster blower 704 may include any suitable type of blower, such as a centrifugal blower, a positive displacement compressor, a fan, a reciprocating compressor, any other suitable compressor with any number of suitable stages, or any suitable combination thereof. In some embodiments, the booster blower 704 includes a motor configured to drive the compressor directly (e.g., directly driven) or indirectly (e.g., by using gears, belts, pulleys, and other connecting rods). In some embodiments, for example, the booster blower 704 includes a centrifugal compressor driven by an electric motor. For example, the motor may be driven by a variable frequency drive (e.g., Figure 3 In some embodiments, the boost blower 704 comprises a centrifugal compressor coupled to a radial gas turbine (e.g., as a turbocharger coupled to an intake system and an exhaust system) via a shaft. In some embodiments, reference Figure 2, for example, the boost blower 704 can be displaced or supplemented by air redirected from the gas springs 298 or 299 of the driver sections 258 and 250, respectively. In some embodiments, the boost blower 704 provides air or an air-fuel mixture at a desired pressure to the manifold system 710. According to the present disclosure, the linear generator system can include any suitable type of boost blower (e.g., turbocharger, supercharger), any suitable number of boost stages (e.g., one or more compression stages), with any suitable auxiliary systems (e.g., intercooling system, oil supply system, blow-off safety system).

[0136] The intercooler 706 is configured to cool the incoming air, incoming fuel, or air-fuel mixture downstream of the booster blower 704. The booster blower 704 will generally increase the temperature of the intake air due to work input due to, for example, thermodynamics and / or machine inefficiency. This temperature increase is generally undesirable because it reduces the density of the intake air, and in some cases, it affects the amount of trapped mass that can be achieved in the cylinder, and it may also affect the ignition in the reaction section. For example, the gas temperature increase of the trapped gas may cause compression ignition to occur at a relatively advanced timing, reduce the operating compression ratio, or both, which are undesirable. The intercooler 706 can be air-cooled (e.g., by an air cooling system), liquid-cooled (e.g., by a liquid cooling system), or both. In some embodiments, the intercooler 706 includes a radiator heat exchanger having a fan to blow gas (e.g., atmosphere) across the cooling fins. In some embodiments, the intercooler 706 may be enclosed and include a flowing fluid to flowing fluid heat transfer (e.g., a cross-flow heat exchanger, a counter-flow heat exchanger, or a parallel flow heat exchanger). In some embodiments, the intercooler 706 includes one or more heat pipes configured to transfer heat from the intake air. For example, a liquid-filled heat pipe can be used to transfer heat from the intake air with or without a phase change. In another example, the heat pipe may be closed and have no input or output flow (e.g., a sealed tube contains a fluid that operates via a capillary effect). In another example, the heat pipe may be open, thereby allowing fluid flow (e.g., including a flow channel and a separate radiator). The intercooler 706 may include any suitable intercooling fluid capable of accepting energy from the intake air. For example, the intercooling fluid may include water, air, propylene glycol, ethylene glycol, a refrigerant, a corrosion inhibitor, any other suitable fluid, any other suitable additive, or any combination thereof.

[0137] The manifold system 710 interfaces to the cylinder and is configured to manage the flow of intake air to the intake vent port of the cylinder. The intake air may include incoming air, fuel (e.g., gaseous or dispersed liquid droplets), an air and fuel mixture, an oxidant and fuel mixture, and any other suitable fluid such as recirculated exhaust gas, water vapor, or other suitable fluid. In some embodiments, the manifold system 710 includes flow channels, vortex introduction elements, mixing introduction elements, flow dividers, or other features that can collect, distribute, mix, or otherwise provide suitable intake air to the cylinder. In some embodiments, the intake system need not include a manifold, and may include a plenum or other suitable component. In some embodiments, the manifold system 710 is configured to work in conjunction with the intake port of the cylinder of the generator assembly to provide intake air to the cylinder.

[0138] In some embodiments, the fuel system is configured to supply fuel to the intake system 700. Figure 7 , a fuel system is not included as part of the intake system, however, in some embodiments, the fuel system may be integrated into the intake system 700. In some embodiments, fuel is supplied to the incoming air downstream of the filter 702, downstream of the boost blower 704, downstream of the intercooler 706, or into the manifold system 710 to form an air-fuel mixture (e.g., before flowing through the intake ventilation port). In another example, in some embodiments, fuel is supplied to the manifold system 710 for manifold injection, near-port injection, port injection, or a combination of injection arrangements. In some embodiments, the intake system 700 does not have to be interfaced to the fuel system. For example, the fuel injection may be injected directly into the bore of the cylinder block (e.g., direct injection). Additional details regarding the fuel system are included in, for example Fig.15 in the description of the context.

[0139] It should be understood that the integrated linear generator system may include any, all, or none of the components discussed in the context of the intake system. For example, an intake vent port of the generator assembly may be coupled to atmosphere (eg, to achieve natural aspiration). Figure 4-17 Illustrative vent ports and vent port arrangements are shown, which may correspond to any of intake vent ports, exhaust vent ports, and gas spring vent ports.

[0140] Figure 8 A side view of an illustrative vent port 820 in a cylinder 810 is shown, in accordance with some embodiments of the present disclosure. Fig. 9 Demonstrating some embodiments of the present disclosure Figure 8810. As shown, the vent port 820 includes a plurality of illustrative oval openings (e.g., elongated in the axial direction) extending through the side wall of the cylinder 820 and arranged at axial positions of the cylinder 810 (e.g., having end positions or center positions aligned with specific spatial positions along the axial direction of the cylinder). Figure 8-9 820 , the piston ring 830 is also shown in a position where the piston ring 830 axially overlaps the vent port 820 (e.g., the port is open or partially open). In some embodiments, as shown, the piston ring 830 includes a ring gap 831. If the ring gap 831 is clocked in position to be covered by the port bridge in the port bridge 811 (i.e., the solid material between the ports of the vent port 820), the end of the piston ring 830 is supported during axial movement over the length of the vent port. However, if the ring gap 831 is clocked in position (e.g., rotated in position about an axis defining an axial direction) into the vent port in the vent port 820 (e.g., as Figure 8-9 ), there may be a risk of radial movement and high shear stresses (e.g., which may damage the end of piston ring 830). In some cases, vent ports with large azimuth openings (e.g., short bridges) may be relatively sensitive to misalignment of the ring gap with the bridge. In some embodiments, the rings include anti-rotation features to prevent clock-like rotation of the rings so that the ring gap remains azimuthally aligned with the port bridge.

[0141] Fig.10 A side view showing an illustrative vent port 1020 in a cylinder 1010 sized and arranged to reduce hoop stress according to some embodiments of the present disclosure. Fig.10 The illustrative ventilation port 1020 of includes staggered holes (e.g., in a hexagonal array, as shown) separated by port bridges 1011, wherein the diameter of each hole is less than Figure 8 Because the length scale (e.g., diameter, as shown) of vent port 1020 is relatively smaller than the length scale of vent port 820, the ring gap may be less sensitive to becoming completely located in the vent port 1020 (e.g., at least a portion of the ring gap is always covered by the bridge). In some embodiments, with a relatively small port size, the ring does not have to be pinned or otherwise constrained to resist rotation in the piston ring groove (e.g., does not have to include an anti-rotation feature). Fig.10 The bridge ratio Figure 8 The bridge shown in FIG. 1 is more of a mesh structure. Accordingly, the ports and corresponding bridges may be of any suitable shape. In some embodiments, the Figure 8A relatively large port opening of the vent port 820. For example, a large opening (e.g., larger than a length dimension of the ring, such as the axial thickness) can reduce flow losses from surface friction. In some embodiments, a relatively large port opening of the vent port 820 can be used. Fig.10 The relatively small and staggered openings of the vent ports 1020 of the ring can be used. For example, small openings (e.g., smaller than a length dimension of the ring, such as the axial thickness) can help reduce the probability of ring damage. In some embodiments, alternative port shapes can be used to meet one or more competing criteria, including, for example, improved ventilation and improved ring wear. For example, in some embodiments, the port can have a shape similar to Figure 8 , but each port has a narrower width in the lateral or azimuthal direction, and / or a longer dimension in the axial direction (e.g., similar to an ellipse). These oval or other oval ports can provide a larger open surface area than the vent port 1020, while providing greater ring wear properties than the vent port 820. According to the present disclosure, the cylinder body may include any suitable port shape and size, or a combination of shapes and sizes. For example, the port may include a hole, a gap, an oval, a polygon, a rounded polygon, a composite shape opening, any other suitable opening, or any combination thereof. In some embodiments, the size and / or shape of the vent port may be configured to reduce the pressure drop of the gas flowing through the port, prevent unsupported ring gaps, reduce ring wear, produce desired ventilation behavior, or a combination thereof. In some embodiments, the vent port may be axially long enough so that the piston seal does not move completely axially outward from the vent port. For example, when the piston is at BDC, the port may be long enough (in an axially outward direction from TDC) so that at least a portion of the port opens forward of the sealing ring on the piston (e.g., allowing exhaust gas in the cylinder to flow into the exhaust manifold), and at least a portion of the port opens rearward of the sealing ring on the piston (e.g., allowing gas in a rear section of the piston to flow out of the cylinder and into the exhaust manifold).

[0142] Fig.11 A cross-sectional end view of an illustrative shaped vent port 1120 in a cylinder 1110 is shown according to some embodiments of the present disclosure. The vent port 1120 includes a larger cross-sectional area at the exterior (e.g., outside of the cylinder 1110) than at the interior (e.g., at the bore cylinder 1110). Fig.12 A cross-sectional end view of an illustrative shaped vent port 1220 in a cylinder according to some embodiments of the present disclosure is shown. The vent port 1220 includes a smaller cross-sectional area at the outside (e.g., outside the cylinder 1210) than at the inside (e.g., at the bore cylinder 1210). For example, in some embodiments, the intake vent port may be similar to Fig.11The vent port 1120 shown in FIG. 1 is shaped to reduce pressure loss across the port compared to a sharp edge (e.g., reduce the boundary layer of flow from the outside to the inside through the port). In another example, in some embodiments, the exhaust vent port may be similar to Fig.12 The vent port 1220 shown in FIG. 1 is shaped to reduce pressure losses across the port compared to a sharp edge (e.g., to reduce the boundary layer of flow passing through the port from the inside to the outside). Accordingly, the expected direction of the average flow can provide an indication of how the vent port should be configured to reduce losses (e.g., where the port is shaped as a nozzle rather than a diffuser relative to the flow direction). In some embodiments, the vent port may include Figure 11-12 The vent port may include a composite shape (e.g., having a wide-narrow-wide cross-sectional configuration) as shown in FIG. 1 . For example, the vent port may include a composite curve, a segmented configuration, any other suitable configuration, or any combination thereof. In some embodiments, the vent port may include an azimuthal path or feature (e.g., to introduce an azimuthal component or "vortex" to the flow). In some embodiments, the vent port may include an axial path or feature (e.g., axially tilted forward or backward to introduce an axial component to the flow).

[0143] Fig.13 An axial cross-sectional view of an illustrative integrated linear generator system portion 1300 configured for premixed air and fuel according to some embodiments of the present disclosure is shown. The integrated linear generator portion 1300 includes a cylinder block 1302 and a manifold 1304. The cylinder block 1302 includes an intake vent port 1310. Although for purposes of discussion Fig.13 13. In some embodiments, the intake ports may be replaced with a design including a plurality of smaller diameter holes or any other suitable shape. For example, a smaller diameter hole (e.g., Fig.10 1304 and cylinder 1302 (referred to herein as the "manifold volume"), enter the intake vent port 1310, and flow into the hole 1303 when the corresponding piston uncovers the intake vent port 1310 and the pressure field directs the flow into the hole 1303 (e.g., during the venting process). The flow in the manifold volume may be due to the piston ( Fig.13 (not shown) opens and closes the intake vent port 1310, the piston ( Fig.13In some embodiments, the manifold volume, the manifold geometry, or both may be selected to enhance ventilation, make the flow field more symmetrical between the intake vent ports, reduce pressure losses, introduce vortices, tumbles, or a combination thereof. For example, features such as pulse tubes may be used to promote vortices or tumbles. The introduction of vortices or tumbles may improve the removal of residual gases from the reaction cylinder holes and / or improve the fuel and air mixing of the intake. The seal 1320 is configured to seal between the manifold 1304 and the cylinder 1302. For example, the seal 1320 may include a gasket, an O-ring, a curing sealant bead, a press fit, any other suitable seal, or any combination thereof. In some embodiments, the vent port 1310 is sized so that the flow through the vent port 1310 causes a greater pressure drop than in the manifold volume. In some embodiments, manifold 1304 may be sized to ensure a desired level of mixing (ie, homogeneity) of air and fuel prior to entering cylinder 1302 .

[0144] Fig.14 A cross-sectional view of an illustrative integrated linear generator system portion 1400 configured for near-port or intra-port injection according to some embodiments of the present disclosure is shown. The integrated linear generator portion 1400 includes a cylinder 1402 and a manifold 1404. The cylinder 1402 includes an intake vent port 1410. Although not shown for clarity, the Fig.14 1402, any suitable number of intake vent ports may be included at any suitable spacing in accordance with the present disclosure. Air enters manifold 1404, is distributed in the manifold volume between manifold 1404 and cylinder block 1402, enters intake vent port 1410, and flows into hole 1403 when the corresponding piston uncovers intake vent port 1410 and the pressure field directs flow into hole 1403 (e.g., during the ventilation process). The flow in the manifold volume may be due to the piston ( Fig.14 (not shown) opens and closes the intake vent port 1410, the piston ( Fig.14In some embodiments, the manifold volume, manifold geometry, or both may be selected to enhance ventilation, make the flow field more symmetrical between the intake vent ports, reduce pressure losses, introduce vortices, tumbles, or a combination thereof. Fuel injectors 1430 are configured to deliver fuel to corresponding ones of the intake vent ports 1410. In some embodiments, each of the intake vent ports 1410 may have, but need not have, a corresponding fuel injector (e.g., similar to fuel injector 1430). In some embodiments, fuel injectors 1430 are configured to deliver fuel during a predetermined time period. For example, fuel injectors 1430 may be configured to inject fuel only during the ventilation process (e.g., when the intake vent port 1410 is uncovered by the corresponding piston). In another example, the fuel injector 1430 may be configured to inject fuel only during a time window of the ventilation process to limit the amount of fuel that does not enter the orifice 1403 during the ventilation process (e.g., so that the fuel does not accumulate in the manifold 1404), limit the amount of fuel that blows through the cylinder during the ventilation process (e.g., so that the fuel does not enter and exit the orifice 1403 during the ventilation process), or both. In some embodiments, the fuel injector 1430 is configured to deliver fuel continuously. Although shown as partially inserted into the intake vent port in the intake vent port 1410, the fuel injector 1430 does not have to be inserted into the intake vent port in the intake vent port 1410. For example, the fuel injector 1430 may generate a fuel jet that is directed to the intake vent port and enters the intake vent port due to momentum effects (e.g., the velocity of the jet). The fuel injector 1430 may include any suitable type of fuel injector capable of delivering fuel to the intake vent port. For example, the fuel injector 1430 can be configured for near-port injection, in-port injection, or both. The seal 1420 is configured to seal between the manifold 1404 and the cylinder 1402. For example, the seal 1420 can include a gasket, an O-ring, a bead of curing sealant, a press fit, any other suitable seal, or any combination thereof. Although shown as sealing directly against the cylinder 1402, the seal 1420 need not engage directly against the cylinder 1402. For example, the seal 1420 can seal against another component of the integrated linear generator system (e.g., a bearing housing, a rod seal).

[0145] Fig.15A cross-sectional view of an illustrative integrated linear generator system portion 1500 configured for injection upstream of an intake vent port 1510 is shown in accordance with some embodiments of the present disclosure. The integrated linear generator portion 1500 includes a cylinder block 1502, a manifold 1504, a plenum 1531, intake runners 1591-1594, a fuel injector 1530, and a seal 1520. The seal 1520 is configured to seal between the manifold 1504 and the cylinder block 1502 (e.g., to prevent leakage into or out of the intake system). For example, the seal 1520 may include a gasket, an O-ring, a bead of curing sealant, a press fit, any other suitable seal, or any combination thereof. In some embodiments, the fuel injector 1530 is configured to inject fuel into the plenum 1531, which receives incoming air (e.g., from a boost blower and / or an intercooler, and / or a filter). The air and fuel mixture flows from the plenum 1531 through the intake runners 1591, 1592, 1593, and 1594 to the respective intake vent ports 1510. In some embodiments, the intake runners 1591-1594 have the same or similar lengths, thereby providing similar residence times of the intake air within the respective intake runners. For example, the intake runners 1591-1594 may be tuned (e.g., having geometric properties such as length and cross-sectional area) to have flow paths that produce specific ventilation characteristics. Fig.18 Air and fuel mixtures are further discussed in the context of . According to the present disclosure, an intake system may include any suitable number (eg, one or more than one) of plenums, fuel injectors, breather ports, breather enhancement features in any suitable arrangement.

[0146] In some embodiments, the intake runners 1591-1594 are sealed to corresponding ports in the intake vent ports 1510 so that the intake air flow in the intake runners does not leak into the manifold 1504. In some embodiments, the air chamber 1531 is open to the manifold 1504 (e.g., the air chamber 1531 and the manifold 1504 are the same). In some embodiments, the manifold 1504 need not be included (e.g., the intake runners 1591-1594 are sealed to the air chamber 1531). In some embodiments, the intake runners 1591-1594 do not need to be directly engaged against the cylinder block 1502 or the intake vent ports 1520. For example, the ends of the intake runners 1591-1594 can be arranged to be close to the corresponding intake vent ports 1520, but not sealed against the corresponding intake vent ports 1520.

[0147] Fig.16A diagram showing an illustrative intake manifold arrangement 1600 according to some embodiments of the present disclosure is shown. The arrangement 1600, shown from the side of the generator assembly on the intake side, shows split intake. Split intake is a method of selectively injecting a relatively lean or rich air / fuel mixture into a reaction cylinder during the ventilation process (e.g., lean front). As shown, air and fuel are provided to the intake manifold 1610. Shields 1650 and dividers 1660 separate zones 1611 and 1612 from each other. Fuel is provided to zone 1611 (e.g., using injectors 1670), and air is provided to zone 1612. Shields 1650 allow some air from zone 1612 to enter zone 1611 and mix with the fuel in zone 1611. Accordingly, the gas mixture in zone 1611 is more than the gas mixture in zone 1612 (e.g., the equivalence ratio in zone 1611 is greater than the equivalence ratio in zone 1612). Divider 1660 provides axial division of the intake air flow into the bore of cylinder 1602. As shown, divider 1660 may be porous, perforated or otherwise gas permeable (e.g., as indicated by arrows), but provides at least some restriction on mixing between zones 1611 and 1612. Zone 1612 is arranged axially inward of zone 1611 (e.g., as indicated, toward TDC) to allow relatively lean intake air to enter the bore of cylinder 1602 during ventilation. This axial division of intake air may reduce the concentration of unreacted fuel in the exhaust gas due to blow-through. For example, the intake charge in the bore of cylinder 1602 may be relatively less toward the exhaust side of cylinder 1602 when the exhaust port is closed. In some embodiments, divider 1660 extends radially inward to the outer surface of cylinder 1602 at intake port 1603. In some embodiments, divider 1660 is sealed to the intake manifold by seal 1661 as shown.

[0148] In the illustrative example, during the power stroke of the linear generator, the intake translator 1620 is moved away from TDC (e.g., away from the exhaust vent port). When the sealing ring uncovers the intake vent port 1603, gas from zone 1612 of the intake manifold 1610 begins to enter the cylinder 1602. The zone 1612 closest to the centerline of the cylinder 1602 contains gas with a relatively low concentration of fuel. As the translator 1620 begins to open the intake vent port 1603, gas from zone 1612 enters the cylinder 1602 first. Fuel is injected (e.g., using injector 1670) into zone 1611 farther from the centerline of the cylinder 1602 (e.g., away from TDC), so that zone 1611 contains a zone with more fuel. Gases in zone 1611 enter cylinder 1602 later in the ventilation cycle because it takes some time for translator 1620 to uncover the portion of intake ventilation port 1603 corresponding to zone 1611. Shield 1650 may be used to control the relative flow of fresh air from zone 1612 into zone 1611. For example, the porosity or open area of ​​shield 1650, the position (e.g., axial or radial position) of shield 1650, the porosity or open area of ​​divider 1660, the position (e.g., axial position of divider 1660), or a combination thereof, affect the division of intake air flowing from intake manifold 1610 to cylinder 1602.

[0149] Fig.17A cross-sectional side view of an illustrative intake portion 1700 of a linear generator according to some embodiments of the present disclosure is shown. Intake portion 1700 is similar to intake portion 1600, except that divider 1760 is intake impermeable, while divider 1660 is intake permeable. Air and fuel are provided to zone 1711 of intake manifold 1710, as shown. Shield 1750 and divider 1760 separate zones 1711 and 1712 from each other. Fuel and air are provided to zone 1711, and air is provided to zone 1712. Shield 1750 allows the intake air to be divided into a first air flow provided to zone 1612 and a second air or air and fuel flow provided to zone 1711. In some embodiments, shield 1750 divides the intake air into zones 1711 and 1712, and fuel is provided to zone 1711 using optional fuel injector 1770. Accordingly, the gas mixture in zone 1711 is more than the gas mixture in zone 1712 (e.g., the equivalence ratio in zone 1711 is greater than the equivalence ratio in zone 1712). For example, the equivalence ratio in zone 1712 may be zero, or close to zero (e.g., zone 1712 may contain air without fuel). Divider 1760 provides axial division of the intake air flow into the bore of cylinder 1702. Divider 1760 is impermeable to intake air (e.g., as shown by arrows), thereby preventing mixing between zones 1711 and 1712. Zone 1712 is arranged axially inward of zone 1711 (e.g., as indicated, toward TDC) to allow relatively lean intake air to enter the bore of cylinder 1702 during ventilation. This axial division of intake air may reduce the concentration of unreacted fuel in the exhaust due to blow-through. For example, the intake charge in the bore of cylinder 1702 may be relatively less toward the exhaust side of cylinder 1702 when the exhaust port is closed. In some embodiments, divider 1760 extends radially inward to the outer surface of cylinder block 1702 at intake port 1703. In some embodiments, divider 1760 is sealed to the intake manifold by seal 1761 as shown.

[0150] Fig.18 A system diagram showing an illustrative fuel system 1800 according to some embodiments of the present disclosure. In some embodiments, the air intake system 400 includes the fuel system 1800. In some embodiments, the fuel system 1800 need not be included in the air intake system. Fig.18 The fuel system 1800 illustratively shown in FIG. 1 includes a fuel filter 1802, a fuel compressor 1804, and a fuel valve 1806. The fuel system 1800 receives a suitable fuel from a fuel supply, which may include, for example, a tank (e.g., a propane tank, a diesel tank, a storage tank), a pipe or pipeline (e.g., a natural gas or biogas pipeline), or any other suitable fuel source. In the illustrative example, the fuel system 1800 may be connected to Figure 7 The fuel system is the same.

[0151] Fuel filter 1802 is configured to filter undesirable components from fuel, such as water, particles, condensable steam, sulfur, siloxane or other ingredients. In some embodiments, fuel system 1800 does not need to include fuel filter 1802. For example, fuel supply, source or reservoir can provide fuel (e.g., utility pipeline natural gas) with sufficient composition or cleanliness and correspondingly does not need to be further filtered. Optional fuel compressor 1804 is configured to increase the pressure of fuel. In some embodiments, fuel compressor 1804 is configured to provide a large increase in the pressure of fuel for use in a high pressure drop fuel injector (e.g., for gaseous or liquid fuel). In some embodiments, fuel compressor 1804 is configured to provide a relatively small increase in pressure. For example, fuel valve 1806 may include a carburetor-type fuel valve, and fuel compressor 1804 can increase the pressure of fuel to be sufficient for fuel valve 1806 operation. In some embodiments, fuel system 1800 does not need to include fuel compressor 1804. For example, a fuel supply, source, or reservoir may provide fuel at sufficient pressure, and accordingly, further boost may not be required. The fuel compressor 1804 may be selected based on the fuel injection technique used. For example, the fuel compressor 1804 may be capable of generating relatively high pressures (e.g., much greater than the boost pressure of the intake air) to enable direct injection or near-port injection within a suitable time scale (e.g., a time scale less than a cycle period). In another example, the fuel compressor 1804 need not be capable of generating high pressures, but may generate pressures greater than the boost pressure of the air, especially when the time scale of injection is relatively long or the fuel injection is continuous. In some embodiments, one or more gas springs (e.g., Figure 2 204 and / or 205), gas spring reservoir (e.g., Figure 2 273 and / or 274 ) or a combination thereof may be configured to compress fuel to supplement, replenish, or eliminate the need for fuel compressor 1804 .

[0152] The exhaust system is configured to facilitate the removal of reaction products from the cylinder to the atmosphere. For example, the exhaust system is configured to direct the removal of reaction products during ventilation. Figure 17-19 An illustrative intake system and components thereof according to the present disclosure are shown. The exhaust system can be configured to reduce or prevent blow-through (i.e., intake air flows into the intake breather port and out of the exhaust breather port during the breather process). For example, blow-through can allow unreacted fuel to reach the exhaust system in some cases. In addition, the exhaust system can be configured to assist in drawing intake air into the cylinder during the breather process.

[0153] Fig.19A system diagram of an illustrative exhaust system 1900 is shown according to some embodiments of the present disclosure. Exhaust system 1900 optionally includes, for example, an exhaust manifold system 1902, a tuning duct 1910, a stinger 1912, an optional radiation / noise pollution device 1914, corresponding piping, sensors, any other suitable components, or any suitable combination thereof. In some embodiments, exhaust system 1900 may include a heat exchanger ( Fig.19 The exhaust gas flows from the bore of the cylinder through the exhaust vent port ( ) when uncovered by the corresponding piston (e.g., during the venting process). Fig.19 In some embodiments, when the piston uncovers the exhaust vent port, the gas pressure in the cylinder is greater than the gas pressure in the manifold system 1902 (e.g., in some cases, sufficient to form a choke at the exhaust vent port), and a venting pulse (e.g., a pressure wave that propagates through the exhaust) occurs. The tuning duct 1910 is configured to utilize the venting pulse (e.g., the energy in the pressure wave) to enhance the ventilation process. For example, the tuning duct 1910 can be configured to generate a suction pulse (e.g., to assist in drawing intake air into the cylinder) and a choking pulse (e.g., to reduce blow-through and increase the pressure in the cylinder) in response to the venting pulse during the ventilation process. Accordingly, the transient ventilation process and the tuning duct cause the flow in the manifold system 1902 to be unstable. The venting pulse, the suction pulse, and the choking pulse are examples of pressure waves (e.g., having peaks, valleys, or other features of pressure) that propagate through the exhaust system and the gas in the cylinder bore.

[0154] The tuning conduit 1910 includes a flow channel 1904, a diverging section 1906, an optional section 1907 having a fixed cross-sectional area, and a converging section 1908. In some embodiments, the flow channel 1904 may include a section of tubing having a fixed diameter, cross-sectional area, or both at either end of the tuning conduit 1910 (e.g., separated from the section 1907). In some embodiments, the diverging section 1906 has a predetermined length, a predetermined first diameter or first cross-sectional area, and a predetermined second diameter or second cross-sectional area. For example, the diverging section 1906 may be shaped as a hollow frustum section (e.g., a right angle or an inclined frustum) having a smaller cross-sectional area closer to the manifold system 1902. The converging section 1908 is downstream of the diverging section 1906 and may be shaped as a hollow frustum section (e.g., a right angle or an inclined frustum) having a smaller cross-sectional area directed downstream. The length, cross-sectional area, and arrangement of the tuning duct 1910 may affect the performance of the generator assembly, and in particular may affect the ventilation process. For example, the length of the tuning duct 1910 may be configured to affect ventilation characteristics (e.g., the timing of suction waves or occlusion pulses). In some embodiments, the section 1907 comprises a constant diameter. In some embodiments, the spatial dimensions of the tuning duct may be determined based on the desired operating characteristics of the linear generator, such as power output, air and / or fuel flow, operating frequency, radiation, or any other suitable operating characteristic. In some embodiments, the tuning of the tuning duct 1910 is unique to the operating frequency of the generator assembly, or is otherwise based on the operating frequency of the generator assembly. For example, the timing and phasing of the pressure wave may be tuned to a specific engine frequency or frequency range. In an illustrative example, the generator assembly may be configured to operate within a relatively limited frequency range for which the tuning duct 1910 is tuned. For example, the tuning duct 1910 may be tuned for a frequency range from ideal to full load (less than 10%, 20%, 30%, 40%, or 50%).

[0155] Downstream of the converging section 1908 is a stinger 1912. In some embodiments, the stinger 1912 comprises a conduit having a relatively smaller diameter or cross-sectional area than a portion of the tuning duct 1910. The stinger 1912 may be disposed at any suitable location on the tuning duct 1910 and provides an outlet for exhaust gas to flow out of the tuning duct 1910. In some embodiments, the diverging section 1906 is connected to an expansion volume (e.g., an expansion tank) of the displacing section 1907 and the converging section 1908, and the stinger 1912 is connected to this expansion volume.

[0156] Optional radiation / noise pollution equipment 1914 is arranged downstream of the stinger 1912. The radiation / noise pollution equipment 1914 can be configured to assist in balancing the chemical composition of the exhaust gas (e.g., by selectively catalyzing the reaction), reducing the noise output, or both. For example, in some embodiments, the radiation / noise pollution equipment 1914 includes an oxidation catalyst configured to assist in oxidizing unburned hydrocarbons, carbon monoxide, or any other suitable fuel or partial combustion products. In another example, in some embodiments, the radiation / noise pollution equipment 1914 includes a three-way catalyst configured to assist in oxidizing unburned hydrocarbons, carbon monoxide, or any other suitable fuel or partial combustion products and reducing nitrogen oxides (e.g., reducing NOx content). In another example, in some embodiments, the radiation / noise pollution equipment 1914 includes a selective catalytic reduction (SCR) system configured to assist in reducing nitrogen oxides. In some embodiments, the radiation / noise pollution equipment 1914 includes an SCR system, a catalyst, a muffler, a combination thereof, or none of these components. In some embodiments, the exhaust system need not include the emission / noise pollution device 1914. For example, the exhaust vent port or tuning duct can be discharged directly to the atmosphere. In some embodiments, the exhaust system need not include a muffler, and the exhaust duct is used to suppress noise. In some embodiments, the volume or space of the package (e.g., the housing of the linear generator system) is used to suppress noise, and a separate muffler assembly need not be included (e.g., the elimination of the muffler can achieve more usable space in the package / housing). In some embodiments, the emission / noise pollution device 1914 includes suitable ducting (e.g., acoustic ducting) inside or outside the package / housing, sound attenuation or soundproofing panels, any other suitable features configured to reduce the intensity of sound waves, any other suitable features configured to reduce audible noise outside the package, or any combination thereof.

[0157] According to some embodiments of the present disclosure, the tuning conduit may include simple bends, compound bends, or both of any suitable path and shape. For example, the tuning conduit may be bent, coiled, curled, or otherwise reduce or modify the overall footprint to accommodate packaging constraints.

[0158] Fig. 20 An axial cross-sectional view of an illustrative integrated linear generator system portion 2000 configured for exhaust according to some embodiments of the present disclosure is shown. Integrated linear generator portion 2000 includes a cylinder block 2002 and a manifold 2004. Cylinder block 2002 includes exhaust vent ports 2010. Although not shown for clarity, Fig. 202010 are illustratively shown spaced ninety degrees apart, but any suitable number of exhaust vent ports may be included at any suitable intervals and spacings in accordance with the present disclosure. Although shown as having a single outlet, the exhaust manifold may include any suitable number of outlets (e.g., one or more outlets). The exhaust vent ports may be shaped to reduce ring wear and / or direct exhaust flow (e.g., such as Fig.11 and 12 In some embodiments, the exhaust port may include multiple small diameter holes or any other suitable shape that can reduce piston ring wear and improve uniform flow into the manifold (e.g., as described in the context of FIG. 1 ). Figure 8-12 2002). When the corresponding piston uncovers the exhaust vent port 2010 and the pressure field directs flow from the hole 2003 (e.g., during the venting process), the exhaust gas flows out of the hole 2003 and into the manifold 2004, thereby flowing into the volume between the manifold 2004 and the cylinder 2002 (referred to herein as the "manifold volume"). The flow in the manifold volume may be attributed to the piston ( Fig. 20 2004 and cylinder 2002. For example, the seal 2020 may include a gasket, an O-ring, a bead of curing sealant, a press fit, any other suitable seal, or any combination thereof.

[0159] In some embodiments, the exhaust manifold and exhaust vent ports are designed to merge flows from all exhaust vent ports into one or more outlets in the hope of maintaining low pressure losses, efficient transmission of pressure waves, a substantially uniform azimuthal pressure configuration, a substantially uniform azimuthal temperature configuration, or any combination thereof. In some embodiments, this performance is achieved by avoiding sharp bends or sudden changes in the cross-sectional area of ​​the manifold system. In an illustrative example, each exhaust vent port may include a corresponding flow channel bounded by one or more curved blades extending from a cylinder port bridge. The curved blades guide the exhaust flow from each exhaust vent port into an annular volute. The flow from each exhaust vent port merges with the volute sequentially, and its cross-sectional area increases along its length to accommodate the combined flow. The volute (e.g., one, two, or more volutes) transitions to a single outlet (e.g., a D-shaped outlet) having a total cross-sectional area at least as large as the combined area of ​​the port. Fig.21A cross-sectional view of an illustrative exhaust manifold 2100 is shown according to some embodiments of the present disclosure. The exhaust manifold 1900 includes an internal joint 2101 configured to seal against the cylinder block, vanes 2102, and outlets 2103. In some embodiments, the exhaust manifold 1900 is configured to maintain a sufficiently smooth (e.g., uniform) azimuthal pressure field, a sufficiently smooth (e.g., uniform) azimuthal temperature field, or both. For example, a more uniform pressure field may help maintain an azimuthal more uniform flow of exhaust (e.g., and thus more uniform convective heat of the components). In another example, a more uniform temperature field may help maintain an azimuthal more uniform temperature configuration of the components (e.g., and thus thermal expansion or deformation). In some embodiments, the exhaust manifold 1900 helps eliminate or otherwise reduce bending of the translator due to the effects of non-uniform heating (e.g., thereby potentially causing misalignment and increased wear on the bearing housing). In some embodiments, the exhaust system may include a translator cooling system to provide cooling to the exhaust translator. For example, a stream of compressed gas may be used to impinge or otherwise flow along a surface of the translator to provide convective cooling. In some embodiments, one or both of the intake and exhaust translators are provided with cooling gas to provide translator cooling. In some embodiments, the translator cooler may include features configured for preferential cooling of surfaces of the translator. For example, the translator cooler may be configured to cool one or more surface areas of the translator in preference to the one or more other surface areas of the translator. For example, the translator cooler may include features configured to preferentially cool the location of the translator closest to the exhaust manifold gas outlet (e.g., at the Fig. 20 , or Fig.21 In some embodiments, the translator cooler may include features configured for uniform cooling of the translator.

[0160] A gas spring (GS) system is configured to convert energy from the motion of a corresponding translator into potential energy for slowing the translator at least during an expansion stroke. In some embodiments, the GS system is used to at least partially return the translator (e.g., from BDC). In some embodiments, the GS system is used to partially return the translator (e.g., from BDC), provide compressed gas for use in other areas of the linear generator system (e.g., a bearing system), or both. In some embodiments, the gas spring system is configured to store a sufficient amount of energy during the expansion stroke to at least fully return the translator during a subsequent stroke (e.g., from BDC to TDC) so that no net electrical input is required. For example, the gas of the gas spring may include air, which may be provided to an air bearing interfaced with one or more translators. The gas spring system may include a gas spring assembly (i.e., hardware including a cylinder) that houses a gas spring (i.e., a volume of a suitable gas that can act in the form of boundary work). For example, as the translator moves away from TDC (i.e., outward from the center), the pressure in each respective gas spring increases (e.g., during the compression stroke of the gas spring and the expansion stroke of the reaction section). The compression work done by the translator on the gas spring is stored in the gas spring at least in part as the internal energy of the gas. This stored energy may subsequently be converted to work (e.g., electrical energy) during the same stroke, a subsequent stroke (e.g., during the expansion of the gas spring), or both. In some embodiments, the control system is configured to manage the storage and release of energy in one or more gas springs. For example, in some embodiments, the control system is configured to manage the storage and conversion of energy in one or more gas springs to avoid requiring a net electrical energy input during a stroke (i.e., providing a net electromagnetic work output during a stroke), and thus the integrated linear generator system extracts net electrical energy from the generator assembly during each stroke of the cycle. In another example, in some embodiments, the control system is configured to avoid the need to input electrical energy during a stroke, and to always extract electrical energy during each stroke of the cycle. To illustrate, as the translator undergoes an expansion stroke, the kinetic energy of the translator is partially converted by the LEM into electricity and partially converted into internal energy stored in the gas spring. Furthermore, as the translator undergoes a compression stroke, the energy stored in the gas spring is partially converted into the kinetic energy of the translator, which is partially converted by the LEM into electricity and partially converted into internal energy in the reaction section (e.g., for compressing the reaction mixture). In some embodiments, the control system is configured to provide net electrical energy to the generator assembly, such as when the free piston linear generator is operating as a motor (e.g., during startup). For example, the net electrical energy may be input to accumulate energy (e.g., kinetic energy, internal energy, and potential energy) in the linear generator system prior to the introduction of fuel. In some embodiments, the LEM may be operated as a motor, in which case the control system is configured to supply electrical energy to the translator to move the translator to a desired position.For example, electrical energy may be used by the stator to actuate or assist in actuating the translator to a desired position that is closer or further than the position the translator would have otherwise reached without the input of electrical energy. In some embodiments for which there is a net electrical output during a cycle, there may be time intervals during the cycle when electrical energy is input to the generator assembly (e.g., short time periods of motor driving rather than generating).

[0161] The gas spring system may include, for example, a pair of gas springs. Each gas spring assembly may include a gas spring cylinder having an aperture, a cylinder head, a lower pressure port, a higher pressure port, a valve, a filter, a sensor, any other suitable component, or any suitable combination thereof. In some embodiments, the integrated linear generator system may include a single gas spring assembly. For example, if a single translator is included, a single corresponding gas spring assembly may be included. In some such embodiments, a cylinder head may be included to seal the reaction section. In some embodiments, the integrated linear generator system may include two gas spring assemblies, only one of which includes a low pressure port, a high pressure port, or both. In some embodiments, the integrated linear generator system includes two gas spring assemblies, each of which includes a respective low pressure port and a respective high pressure port. In some embodiments, the lower pressure ports of all gas springs in the integrated linear generator system may be in fluid communication (e.g., connected via a common reservoir or pipeline), the higher pressure ports of all gas springs in the integrated linear generator system may be in fluid communication, or both. In some embodiments, the lower pressure ports of some of the gas springs in the integrated linear generator system may be in fluid communication (e.g., via a common reservoir or conduit connection), the higher pressure ports of some of the gas springs in the integrated linear generator system may be in fluid communication, or both. In some embodiments, no lower pressure ports are in fluid communication, no higher pressure ports are in fluid communication, or both. In some embodiments, the higher pressure ports of one or more gas springs may be used to partially or completely supply compressed gas to gas bearings (e.g., translator bearings, anti-clocking bearings) used in the integrated linear generator system. In some embodiments, the lower pressure gas spring outlet ports may be used to partially or completely supply air to the intake system to reduce or eliminate the power required by the intake boost blower. In some embodiments, the reservoir may be used to reduce pressure waves caused by oscillations of the translator (e.g., from the back side of the gas spring piston). In some embodiments, the reservoir may include a lower pressure inlet port that provides make-up air to the gas springs, a lower pressure outlet port that supplies gas (e.g., air) to the intake system, or both. In some embodiments, the reservoir may be configured to reduce pressure waves, sound, noise, or any combination thereof (e.g., subsonic pressure waves).

[0162] Fig. 22 A cross-sectional view of an illustrative gas spring system 2200 is shown in accordance with some embodiments of the present disclosure. Gas spring system 2200 includes a gas spring cylinder 2202 having a bore 2203, a piston 2250 (e.g., a portion of a translator 2252), a lower pressure port 2204, a higher pressure port 2205, a valve 2215, and a cylinder head 2206. In some embodiments, gas spring 2298 is a volume formed between piston face 2251 and gas spring cylinder 2202 and cylinder head 2206. Seal 2253 is configured to seal gas between piston 2250 and bore 2203, but in some embodiments, seal 2253 is not required. In some embodiments, seal 2253 includes a sealing ring assembly (e.g., formed of graphite, plastic, metal, or other suitable material, and configured to wear against bore 2203, an oil-impregnated sealing ring, or any other suitable sealing ring). In some embodiments, seal 2253 is configured for oil-free operation (eg, seals without the use of oil or liquid for lubrication). Gas spring 2298 is configured to store and release energy during compression and expansion, respectively, as the gas pressure in gas spring 2298 changes.

[0163] In some embodiments, lower pressure port 2204 is configured to allow gas to flow into bore 2203 when piston 2250 (e.g., and seal 2253) uncovers lower pressure port 2204. In some embodiments, lower pressure port 2204 is configured for near-atmospheric venting (e.g., 1 atm ± 0.5 atm), during which atmosphere at atmospheric pressure is drawn into bore 2203 (e.g., where the pressure in bore 2203 is lower than atmospheric pressure). For example, at the end of a stroke as the translator moves from BDC to TDC (e.g., gas spring expansion), the gas pressure in gas spring 2298 may be lower than atmospheric pressure at or near BDC due to losses. For illustration, mass loss may occur from gas spring 2298 through seal 2253, referred to herein as "blow-off", or through higher pressure port 2205 via valve 2215, referred to herein as "higher pressure venting". In some embodiments, gas from behind the seal 2253 (i.e., away from the piston face 2251) can interact with the lower pressure port 2204. For example, in some cases, gas behind the seal 2253 can flow between the lower pressure port 2204 and the volume behind the piston 2250 (i.e., the driver rear section 2270). In some embodiments, the driver rear section 2270 is open to near atmosphere. In some embodiments, the driver rear section 2270 can be open to near atmospheric pressure (e.g., 1atm±0.5atm). In some embodiments, the driver rear section 2270 can be sealed relative to near atmospheric pressure. For example, a gas seal can seal between the translator 2252 and the gas spring cylinder 2202. In another example, the driver rear section 2270 can be sized to reduce or limit the compression work of the gas within the driver rear section 2270 during the stroke of the cycle. In some embodiments, the lower pressure port 2204 is configured for boost air ventilation, during which boost air at a pressure above atmospheric pressure is drawn into the hole 2203. For example, a boost blower can be used to supply intake air (e.g., make-up air) to the lower pressure port 2204, which provides the make-up air to the gas spring 2298. In some embodiments, the lower pressure port 2204 is located in or near the cylinder head 2206 (e.g., but still arranged in the cylinder 2202). Any suitable number of lower pressure ports 2204 of any suitable size, location, or both may be included in the gas spring system. In some embodiments, the lower pressure port 2204 is valved or otherwise controlled relative to "open" or "closed". In some embodiments, the lower pressure port 2204 is configured to allow gas to exit the gas spring 2298.For example, the gas spring system may include a first lower pressure port for supplying make-up air to the gas spring 2298, and a second lower pressure port for delivering air from the gas spring 2298. In the illustrative example, the lower pressure port may be used to supply incoming reaction air (e.g., at a suitable boost pressure, by using a timing valve).

[0164] The higher pressure port 2205 is configured to allow the gas of the gas spring 2298 to exit the hole 2203 when the gas pressure of the gas spring 2298 is above a threshold. In some embodiments, the valve 2215 is configured to prevent gas flow until the pressure of the gas spring 2298 is above a threshold. The threshold can be, for example, the pressure downstream of the valve 2215, the rupture pressure of the valve 2215, or any other suitable threshold. In some embodiments, the higher pressure port 2205 is configured to provide a higher pressure gas to a system outside the hole 2203. For example, in some embodiments, the higher pressure port 2205 can be coupled to a gas bearing system and can supply bearing gas to the bearing system. Accordingly, in some embodiments, the gas spring system can also act as a gas compressor. The valve 2215 can include any suitable type of valve, such as a check valve, a reed valve, or any other suitable passive (e.g., spring loaded) or active (e.g., actuated) valve. In some embodiments, the BDC position is closer to the head 2206 than the higher pressure port 2205. For example, in some embodiments, during the stroke to the BDC position, the seal 2253 may move past the higher pressure port 2205, and thus the gas spring 2298 cannot utilize the higher pressure port 2205 for significant pressure transfer. In some embodiments, when the pressure in the gas spring 2298 is above a threshold and the seal 2253 is not blocking the higher pressure port 2205 nor closer to the head 2206 than the higher pressure port 2205, gas from the gas spring 2298 may flow through the valve 2215. In an illustrative example, the peak pressure in the gas spring 2298 achieved at or near BDC may be twenty bar or more, while the gas exiting the valve 2215 may be six bar or less. This example is merely illustrative, and any suitable location of the higher pressure port 2205 and BDC may be used, and any suitable pressure in the gas spring 2298 (e.g., a few bar to well over fifty bar) may be achieved. Any suitable number of higher pressure ports 2215 of any suitable size, location, or both may be included in the gas spring system. The higher pressure port 2205 may be disposed in the cylinder 2202, the cylinder head 2206, any other suitable component, or any combination thereof (eg, multiple higher pressure ports, or a port formed at a junction of components).

[0165] In some embodiments, the gas spring system need not include a higher pressure port. For example, the gas spring system may include a lower pressure port to provide supplemental air during the venting process to offset blow-by during compression and expansion of the gas spring 2298 (e.g., to maintain near constant cycle-to-cycle operation). In another example, the lower pressure port may include a valve (e.g., disposed in the gas spring cylinder or head) that is coupled to a gas source, supply, or reservoir and configured to allow supplemental gas to flow into the orifice during the venting process. The lower pressure port (e.g., a supplemental air port) may be disposed at any suitable location, including, for example, in the cylinder head (e.g., configured to open only when the translator is near TDC) or in the cylinder wall.

[0166] In some embodiments, the gas spring system need not include a lower pressure port. For example, in some embodiments, when the piston 2250 approaches the TDC position, air from the rear of the piston 2250 (i.e., the rear section 2270 of the actuator away from the piston face 2251) can flow through the seal 2253 into the gas spring 2298.

[0167] In some embodiments, the gas spring system need not include a lower pressure port or a higher pressure port.

[0168] In some embodiments, the gas spring system 2200 may include one or more features 2232 for removing energy from the gas spring 2298, limiting the peak pressure in the gas spring 2298, limiting the compression ratio of the gas spring 2298, limiting the expansion ratio of the gas spring 2298, or a combination thereof. In some embodiments, the gas spring system 2200 includes a pressure relief port 2231, which may optionally include, for example, a pressure relief valve 2230. In some embodiments, the pressure relief valve 2230 is configured to open when the pressure in the gas spring 2298 exceeds a threshold. For example, the pressure relief valve 2230 may include a spring-loaded valve that opens when the pressure in the gas spring 2298 is sufficient to offset the spring force. The pressure relief port 2231 may be included to prevent an overpressure condition in the gas spring 2298 by releasing energy from the gas spring 2298 (e.g., to reduce the force acting on the translator 2252). The optional pressure relief port 2231 may be included in the cylinder head 2206, the gas spring cylinder 2202, or both. Any suitable number of pressure relief ports having any suitable burst pressures may be included in the gas spring system.

[0169] In some embodiments, the gas spring system 2200 includes a pressure relief feature 2232. For example, the pressure relief feature 2232 may include one or more axial grooves or scallops included in the bore of the cylinder 2202 that are configured to provide a leak path around the seal 2253 (i.e., as a blow-by) if the seal 2253 moves past the pressure relief feature 2232 (e.g., to a more extreme BDC position). One or more of the length, axial position, and depth of the pressure relief feature 2232 may be configured to introduce and maintain a leak path for a predetermined position of the piston 2250. In some embodiments, one or more pressure relief features 2232 may be included to provide pressure relief in the gas spring 2298 without requiring mechanical or moving parts (e.g., such as a pressure relief valve 2230).

[0170] In some embodiments, the seal 2253 allows backflow when the pressure in the rear driver section 2270 is greater than the pressure in the gas spring 2298. For example, when the pressure in the gas spring 2298 is greater than the pressure in the rear driver section 2270 (e.g., greater than, greater than according to a threshold value), the seal 2253 can seal against the hole 2203. In another example, when the pressure in the gas spring 2298 is less than the pressure in the rear driver section 2270 (e.g., less than, less than according to a threshold value), the seal 2253 can allow gas from the rear driver section 2270 to flow into the gas spring 2298 (i.e., backflow). To illustrate, in some such embodiments, where the seal 2253 is configured to allow backflow, the cylinder 2202 may not necessarily include the lower pressure port 2204. Makeup gas may enter the gas spring 2298 from the actuator rear section 2270 by flowing through the seal 2253 when the pressure in the actuator rear section 2270 is greater than (or greater than, based on a threshold value) the pressure in the gas spring 2298 .

[0171] Fig.23 A cross-sectional side view of an illustrative gas spring system 2400 having a reservoir 2440 is shown in accordance with some embodiments of the present disclosure. Fig.24 A schematic diagram showing a translator (e.g., including piston 2450) having a second position according to some embodiments of the present disclosure Fig.232400 . Panel 2480 shows the piston 2450 when the translator is near BDC, and panel 2481 shows the piston 2450 when the translator is near TDC, which shows the vent port 2404 open. In some embodiments, the gas spring system may include a reservoir configured to seal between the cylinder 2402 of the gas spring and the bearing housing 2412 of the gas spring. In some embodiments, a seal may be included to seal against the cylinder, the bearing housing, the stator, the structural frame, any other suitable component, or any combination thereof, and then seal against the bearing housing. For example, the reservoir 2440 may be configured to seal against the stator (not shown) to react to axial loads, and against the bearing housing 2412 to reduce axial loads and provide radial compliance. In another example, the reservoir 2440 may seal against the structural frame (not shown), a flange (not shown) of the cylinder 2402, or any other suitable component. As shown, the reservoir 2440 has an associated volume (e.g., volume 2470). As shown, the gas spring system 2400 includes a reservoir supply port 2443. For example, in some embodiments, ambient air (e.g., unconditioned from the environment, or optionally filtered, compressed, cooled, heated, or otherwise conditioned) is supplied via the reservoir supply port 2443 (e.g., using a reed valve 2444 as shown). In the illustrative example, the reservoir 2440 may exhibit venting behavior (e.g., alternating inflow and outflow) as gas is introduced into the reservoir 2440 via the reservoir supply port 2443 and then flows into the gas spring 2498 via the vent port 2404. In some embodiments, as shown, the gas spring cylinder 2402 includes a high pressure port 2405. For example, the high pressure port 2405 may be coupled to a gas bearing system and may be configured to provide pressurized gas to one or more gas bearings of the gas bearing system. In some embodiments, as piston seal 2453 uncovers vent port 2404, gas in volume 2470 of reservoir 2440 flows into gas spring 2498 via vent port 2404 (e.g., to replenish gas lost via high pressure port 2405, gas leakage past piston seal 2453, or both). In some such embodiments, the gas in reservoir 2440 may be sized such that the pressure increases before flowing into gas spring 2498 via port 2404. In some embodiments, reservoir 2440 is sealed against bearing housing 2412 (e.g., by an o-ring, gasket, tight tolerance, or any other suitable seal), thereby effectively forming a seal against translator tube 2452 to prevent flow out of reservoir 2440 (e.g., when the pressure in volume 2470 is less than the gas bearing pressure).As piston 2450 translates (e.g., gas spring 2498 expands and contracts), the pressure in volume 2470 may change accordingly (e.g., generally with a pressure change that is opposite in sign to the pressure change of gas spring 2498). The larger volume 2470 is, the smaller the change in pressure in volume 2470 is. For example, fluctuations in the pressure of volume 2470 may be reduced by increasing volume 2470 (e.g., by increasing the size of reservoir 2440). Conversely, fluctuations in the pressure of volume 2470 may be increased by decreasing volume 2470 (e.g., by decreasing the size of reservoir 2040). In some embodiments, reservoir 2440 is adjustable (e.g., volume 2470 is adjustable). For example, one or more slots, bladders, or any other suitable components may be coupled to reservoir 2440 and may be opened, closed, or otherwise adjusted to adjust the total volume (e.g., volume 2470 plus additional volume). In some embodiments, reservoir 2440 itself may be adjustable using any suitable mechanism, feature, or component. In some embodiments, the reservoir 2440 is configured to seal against a structural frame (eg, not the bearing housing 2412).

[0172] In some embodiments, reservoir 2440 can be used to provide fuel compression. For example, natural gas or other suitable gaseous fuel can be supplied to volume 2270 and can undergo compression through the action of piston 2450, thereby increasing the pressure of the fuel. In some embodiments, gas spring 2498 can be used to provide fuel compression. For example, fuel can be directly admitted into gas spring 2498 (e.g., gas spring 2498 is composed of fuel), or compressed gas of gas spring 2498 can be used to compress fuel (e.g., using higher pressure port 2405 and bladder or piston pump assembly).

[0173] Fig.25 A cross-sectional side view of an illustrative gas spring system 2500 having a reservoir 2540 configured for intake compression is shown in accordance with some embodiments of the present disclosure. As shown, Fig.25 A system similar to Figure 22-24, with the addition of an intake supply valve 2542 and optionally an intake supply groove 2544 disposed at the intake supply port 2541. As the piston 2550 and the seal 2553 move along the axis 2570 in the cylinder 2502, the pressure in the reservoir volume 2570 may change. For example, as the gas spring 2598 expands, the pressure in the reservoir volume 2570 may increase, and as the gas spring 2598 contracts, the pressure in the reservoir volume 2570 may decrease. As shown, as the pressure in the reservoir volume 2570 exceeds the burst pressure of the intake supply valve 2542, gas from the reservoir volume 2570 flows through the intake supply port 2541 into the intake supply groove 2544 and then to the intake system. Accordingly, the rear section of the actuator (e.g., which includes the reservoir volume 2570 and the volume between the translator 2552 and the cylinder 2502) can be used to provide intake air (e.g., air for the reaction cylinder) or otherwise pressurize the intake air to increase the reaction cylinder ( Fig.25 In some embodiments, for example, the post-driver section is used to pressurize the intake air to reduce or eliminate the need for an intake boost blower. In some embodiments, for example, the post-driver section is used to pressurize the intake air in addition to the intake boost blower (e.g., a boost blower that provides gas from the intake supply tank 2544 to the intake system). In some embodiments, the reservoir 2540 may include one or more filters before or after the intake supply valve 2542, before or after the intake supply tank 2544, before the intake system, or a combination thereof. In the illustrative example, the reservoir 2540 may exhibit venting behavior as gas is introduced into the reservoir 2540 via the reservoir supply port 2543 (e.g., shown with a supply port valve 2544) and then flows into the gas spring 2598 via the vent port 2504 (e.g., which may be, but is not, controlled by the optional valve 2580) and out of the intake supply port 2541 to the intake supply slot 2544. In some embodiments, it is not necessary to include an intake supply slot. For example, the volume of the tubing from the intake supply port may include sufficient volume (e.g., to mitigate pressure fluctuations from unstable flow caused by valve opening / closing), and a separate slot may not be required.

[0174] Fig.26A side cross-sectional view of a portion of an illustrative gas spring system 2600 having a reservoir according to some embodiments of the present disclosure is shown. The translator 2620 is configured to move along the indicated axis. The bearing housing 2630 forms a bearing gap 2631 with a surface of the translator 2620 (e.g., to form a gas bearing). The translator 2620 and cylinder 2602 including the seal 2621 define a gas spring 2697 (e.g., acting as a sealed volume for the spring). In some embodiments, the portion of the translator 2620 that defines the gas spring 2697 is a separate but attached piston assembly ( Fig.26 2620 ). Gas spring port 2604, when open (e.g., seal 2621 uncovers gas spring port 2604, as shown), is configured to allow gas from a gas spring supply (e.g., which may include atmospheric air, compressed air, or other suitable gas supply) to enter gas spring 2697. Gas spring port 2604 may be open or valved (e.g., with one or more passive valves, with one or more valves controlled by a control system, or any combination thereof). As shown, reservoir 2640 is sealed against stator 2650, bearing housing 2630, and cylinder 2602 to define volume 2641. Reservoir port 2642 is configured to allow gas to enter volume 2641. Reservoir port 2643 is configured to allow gas to exit volume 2641. In some embodiments, reservoir ports 2642 and 2643 are each valved (e.g., with one or more passive valves, with one or more valves controlled by a control system, or any combination thereof). For example, reservoir port 2643 can be configured to allow gas from volume 2641 to flow to an intake system (not shown) to provide boosted intake air, to flow to a gas spring inlet port (e.g., gas spring port 2604), or both. In some embodiments, reservoir port 2642 (inlet port) need not be included, and only reservoir port 2643 (outlet port) may be included. For example, gas spring inlet port 2604 may be opened to the gas spring when gas spring inlet port 2604 is open to the gas spring (e.g., when seal 2621 is in a position closer to TDC, such as Fig.26 2641 ) provides supply air to the gas spring 2697 and also provides air to the reservoir 2641 when the gas spring inlet port 2604 is closed to the gas spring (and therefore open to the reservoir 2641). In some embodiments, reservoir port 2642 (inlet port) need not be included and reservoir port 2643 (outlet port) need not be included.

[0175] Fig. 27A side cross-sectional view of a portion of an illustrative gas spring system 2700 having a reservoir according to some embodiments of the present disclosure is shown. The translator 2720 is configured to move along the indicated axis. The bearing housing 2730 forms a bearing gap 2731 with a surface of the translator 2720 (e.g., to form a gas bearing). The translator 2720 and cylinder 2702 including the seal 2721 define a gas spring 2797. In some embodiments, the portion of the translator 2720 that defines the gas spring 2797 is a separate but attached piston assembly ( Fig. 27 2720 ​​as an integral part of the translator 2720). The gas spring port 2704, when open (e.g., the seal 2721 uncovers the gas spring port 2704, as shown), is configured to allow gas to enter the gas spring 2797 from the volume 2741. The gas spring port 2704 can be open or valved (e.g., using one or more passive valves, using one or more valves controlled by a control system, or any combination thereof). As shown, the reservoir 2740 is sealed against the stator 2750, the bearing housing 2730, and the cylinder 2702 to define the volume 2741. The reservoir port 2742 is configured to allow gas to enter the volume 2741. The reservoir port 2743 is configured to allow gas to exit the volume 2741. In some embodiments, the reservoir ports 2742 and 2743 are each valved (e.g., using one or more passive valves, using one or more valves controlled by a control system, or any combination thereof). Gas spring system 2700 allows gas in volume 2741 to compress as translator 2720 moves from BDC toward TDC to flow into gas spring port 2704 (when open) at increased pressure. For example, reservoir port 2743 may be configured to allow gas from volume 2741 to flow to an intake system (not shown) to provide boosted intake air.

[0176] Fig.28 A side cross-sectional view of a portion of an illustrative gas spring system 2800 having a reservoir according to some embodiments of the present disclosure is shown. The translator 2820 is configured to move along the indicated axis. The bearing housing 2830 forms a bearing gap 2831 with a surface of the translator 2820 (e.g., to form a gas bearing). The translator 2820 and cylinder 2802 including the seal 2821 define a gas spring 2897. In some embodiments, the portion of the translator 2820 that defines the gas spring 2897 is a separate but attached piston assembly ( Fig.282820 as an integral part of the translator 2820). The gas spring port 2804, when open (e.g., the seal 2821 uncovers the gas spring port 2804, as shown), is configured to allow gas from the volume 2841 to enter the gas spring 2897. The gas spring port 2804 can be open or valved (e.g., using one or more passive valves, using one or more valves controlled by a control system, or any combination thereof). As shown, the reservoir 2840 is sealed against the stator 2850, the bearing housing 2830, and the cylinder 2802 to define the volume 2841. The reservoir port 2842 is configured to allow gas to enter the volume 2841. In some embodiments, the reservoir port 2842 is valved (e.g., using one or more passive valves, using one or more valves controlled by a control system, or any combination thereof).

[0177] In some embodiments, the flow path of gas to or from reservoir 2641, 2741, or 2841 is used to cool one or more components such as an encoder readhead, encoder strip / belt, any other suitable component, or any combination thereof. For example, the encoder readhead may be located on a gas spring cylinder or bearing housing that is at least partially contained within the reservoir, and the gas flow into or from the reservoir may be used to cool the readhead. In another example, the encoder strip or belt may be located on a translator that moves at least partially within the reservoir, and the gas flow into or from the reservoir may be used to cool the encoder strip or belt.

[0178] Fig.29A view of an illustrative gas spring system of an integrated linear generator system 2900 is shown, in accordance with some embodiments of the present disclosure. As shown, cylinder 2902 includes port 2962 (e.g., for receiving gas spring makeup gas) and port 2963 (e.g., for providing gas for a gas bearing to a bearing housing 2916 of the integrated linear generator system 2900). As shown, reservoir 2998 is sealed to cylinder 2902 using seal 2992 and to bearing housing 2916 using seal 2993. As shown, bearing housing 2916 is coupled to stator 2917 (e.g., using one or more mounts, flexures, or other components not shown). Translator tube 2912 and piston 2911 with seal 2979 are configured to move axially along gas spring cylinder 2902. As shown, piston 2911 is positioned axially away from cylinder 2902 for maintenance, inspection, or repair. Hatch 2999 is removable, allowing access to piston 2911, seal 2979, and the end of translator tube 2912. For example, hatch 2999 is attached to reservoir 2998 during operation (e.g., using fasteners, clamps, sliding joints, hinges, or any other suitable attachment), and can seal against reservoir 2998. Reservoir 2998 can include port 2967 for receiving supply gas for provision to port 2962.

[0179] Fig.30 A side cross-sectional view of an illustrative gas spring cylinder assembly 3000 is shown according to some embodiments of the present disclosure. The gas spring cylinder assembly 3000 includes a cylinder 3002, a head 3012, a spacer 3015, an energy absorber 3005, and a vent port 3004. The cylinder 3002 includes a flange 3006 attached to the head 3012 by fasteners 3013. The spacer 3015 is axially arranged between the flange 3006 and the head 3012. The flange 3006, the spacer 3014, and the head 3012 have corresponding recesses to accommodate a sliding bushing 3014 (e.g., in Fig.31 3098 ). The energy absorber 3005 is arranged radially inside the cylinder 3002, as shown. If the translator 3020 travels inward far enough (e.g., toward the center of the corresponding generator assembly), it will contact and deform the energy absorber 3005, which is configured to convert the kinetic energy of the translator. The cylinder 3002 includes a flange 3030 for mounting to the frame system 3050 via fasteners 3031. In some embodiments, a spacer 3015 may be included to affect the compression ratio of the gas spring 3098. Fig.31A side cross-sectional view of an illustrative gas spring cylinder assembly 3000 is shown opened using a sliding bushing 3014 according to some embodiments of the present disclosure. The sliding bushing 3014 allows the head 3012, the spacer 3015, or both to be axially moved a distance from the flange 3006 (e.g., when the fastener 3013 is removed or otherwise loosened). In some embodiments, the distance is sufficient to allow the piston 3021, the seal 3022, the tube 3023, any other suitable hardware, or a combination thereof to be removed, installed, and inspected. For example, the cylinder 3002 can be separated from the assembly position by any suitable length that is sufficient to enable inspection, maintenance, and repair, or any combination thereof. In some embodiments, the spacer 3015 is configured to act as a ring compressor (e.g., for removing rings, installing rings, replacing rings, inspecting rings, or any combination thereof).

[0180] The bearing system is configured to constrain the motion (primarily radial) of the translator with low friction losses. The bearing system may include, for example, contact bearings, non-contact bearings, or a combination thereof, or any other suitable means for supporting the movement of the translator while providing low friction. In some embodiments, the bearing system includes a gas bearing system configured, for example, to provide a layer of gas against the translator to act as a gas bearing for frictionless, near frictionless, or low friction movement of the translator. For example, the gas bearing system may maintain a layer of pressurized gas between the translator and a bearing surface on which the translator moves.

[0181] Fig.32 A system diagram of an illustrative bearing system 3200 according to some embodiments of the present disclosure is shown. The bearing system includes, for example, one or more bearing housings (e.g., bearing housings 3212 and 3214), a regulator 3210, a tank 3208, an optional auxiliary bearing gas supply system 3250 with corresponding filters, compressors, valves, piping, sensors, any other suitable components, or any suitable combination thereof.

[0182] The bearing housings 3212 and 3214 include, for example, bearing surfaces (e.g., which may be porous, include orifices, or both) that are configured to interface to a gas bearing, which in turn interfaces to a translator. In some embodiments, the bearing housing is mounted to the stator. Accordingly, in some such embodiments, alignment of the bearing housing with the stator (e.g., lateral and axial alignment) is maintained, which allows the translator to move linearly along the axis of the linear generator. In some embodiments, the bearing housing includes features for adjusting alignment between the bearing housing and the translator, features for adjusting alignment between the bearing housings, or both. In some embodiments, the bearing housing may include features to automatically adjust for expansion and contraction of the translator tube (e.g., due to thermal expansion or contraction, due to pressure). The bearing housings 3212 and 3214 are configured to provide bearing gas to the gas bearings via, for example, orifices (e.g., of any suitable cross-section) fed from a common supply or multiple supplies, a porous layer fed from a common gas supply or multiple gas supplies, or a combination thereof. In some embodiments, bearing housings 3212 and 3214 are configured to substantially azimuthally surround (e.g., not necessarily azimuthally continuous) a respective translator. In some embodiments, the translator tube may include a bearing surface (e.g., a polished or otherwise smooth surface) configured to interface to a gas bearing. In some embodiments, the inner surface of the bearing housing may be coated with a low friction material (e.g., an abradable powder coating, a graphite-based coating, a ceramic-based coating) to minimize damage (e.g., scratching or wear) to the translator surface or the bearing surface in the event of surface-to-surface contact. In some embodiments, bearing housings 3212 and 3214 are configured to partially azimuthally surround a respective translator.

[0183] Optional groove 3208 is configured to provide a closed volume to collect bearing gas, thereby reducing fluctuations in the bearing gas supply. In some embodiments, for example, groove 3208 is configured to draw gas from a high pressure port (e.g., Fig. 22 High pressure port 2205, Figure 23-24 High pressure port 2405, or Fig.25The bearing gas is received from the high pressure port 2505 of the bearing housing 3212, the auxiliary system 3250, or both. In some embodiments, the auxiliary system 3250 may supply all of the bearing gas to the bearing housing 3212 and the bearing housing 3214. For example, during startup or shutdown or during a maintenance event, the auxiliary supply system 3250 may provide all of the bearing gas to the bearing housing (e.g., when the gas spring system is unable to provide the minimum required bearing gas flow, or when the gas spring system is unable to provide bearing gas at or above the required pressure). The optional regulator 3210 acts as a pressure regulator to deliver bearing gas to the bearing housings 3212 and 3214 at a constant or near-constant pressure. The regulator 3210 may include any suitable type of pressure regulator (e.g., active or passive), flow restriction (e.g., an orifice, a passive valve, or a controllable valve), any other suitable device, or any combination thereof. In some embodiments, a filter ( Fig.32 3214). In some embodiments, the regulator 3210 may be controllable (e.g., manually or remotely) to adjust the pressure to the bearing housings 3212 and 3214. In some embodiments, it is not necessary to include the tank 3208, the regulator 3210, or both, and the bearing gas from the source may be delivered directly to the bearing housings 3212 and 3214. The tank 3208 may include any suitable pressure vessel, such as a tank, a pipe, a box, a plenum, or any other suitable component configured to reduce or limit fluctuations in gas pressure. In some embodiments, the tank 3208 may be implemented using a structural frame of an integrated linear generator system. For example, the structural frame may include a hollow member (e.g., a side member, an end member, a pipe, or other) configured to contain a pressurized gas (e.g., a bearing gas).

[0184] While air is a convenient bearing gas because, for example, it is plentiful and generally readily available, any suitable gas may be used as a bearing gas in accordance with the present disclosure. In some embodiments, the bearing gas is preferably sufficiently dry (e.g., non-condensing), sufficiently clean, and available for compression to a pressure suitable for the desired gas bearing performance. The stiffness of the gas bearing may depend on the pressure of the gas bearing (e.g., higher pressures in the gas bearing may provide greater stiffness, up to instability limits). In some embodiments, the bearing housings 3212 and 3214 may be configured to allow condensed liquid (e.g., water) to collect in the bearing housings, drain from the bearing housings, or both.

[0185] In some embodiments, the gas bearing system can be coupled to the high pressure port of the gas spring system (e.g., Fig. 22 High pressure port 2205, Figure 23-24 High pressure port 2405, or Fig.253205). For example, compressed gas from a gas spring may be extracted from the gas spring during high pressure venting, optionally conditioned, and used as bearing gas. In some embodiments, the high pressure ports of one or more gas springs may be coupled to a reservoir, such as tank 3208, which may supply one or more gas bearings. In some embodiments, the high pressure ports of one or more gas springs on one or more linear generator systems within the same package may be coupled together via a common reservoir or other component and configured to supply gas to one or more gas bearings of the one or more linear generator systems within the same package. In some such embodiments, an external gas compressor may not be required (e.g., but may optionally be included, specifically for startup), thus avoiding the need to include an additional mechanical system. In some embodiments, an external gas compressor is included and is used only during startup, shutdown, or maintenance of the linear generator assembly (e.g., when the pressure in the gas spring is insufficient to supply gas to the gas bearings). Tank 3208 is configured and sized to mitigate the effects of the high pressure venting process that may be attributed to the nature of the high pressure venting process (e.g., via Fig. 22 Valve 2215) pulse controls the pressure fluctuation of the gas from the high pressure port.

[0186] In some embodiments, the auxiliary system 3250 is configured to optionally supply bearing gas to the gas bearing. For example, in some embodiments, during startup of the linear generator, the gas spring system may not yet provide enough gas to act as a gas bearing (e.g., to have sufficient bearing hardness), and the auxiliary system 3250 can be used to provide bearing gas at a suitable pressure. In some such embodiments, the auxiliary system 3250 is deactivated once the gas spring system can provide sufficient bearing gas, but in some embodiments, the auxiliary system 3250 can remain in a standby mode or continue to provide at least some bearing gas (e.g., to replenish the gas spring system). In another example, the auxiliary system 3250 can be configured to provide bearing gas at a suitable pressure and flow rate when the linear generator system is substantially disconnected (e.g., not producing power) during a maintenance event.

[0187] See also Figure 2 , bearing housings 216, 217, 226 and 227 or a subset thereof may be respectively Fig.23 , 24 and 25 high pressure port 2305, 2405 or 2505, a single bearing gas source, auxiliary system 2950, ​​or both. In some embodiments, for example, Figure 2Any of the bearing housings 216, 217, 226, and 227 may be fed by gas spring 298 or gas spring 299. In some embodiments, any gas spring positioned within an enclosure may be fed by any gas spring positioned within the same enclosure, where an enclosure may contain one or more generator assemblies. Fig.33 A cross-sectional view of a generator assembly portion 3300 is shown according to some embodiments of the present disclosure. Generator assembly portion 3300 includes a partial assembly of an integrated linear generator system, including a translator 3360, a stator 3350, bearing housings 3302 and 3304, and gas bearings 3312 and 3314. Translator 3360 includes a tube 3362 that acts as a rigid body to couple pistons and other components to form a rigid translator, a piston 3361 configured to contact a reaction section, a piston 3364 configured to contact a gas spring, and a section 3363 configured to electromagnetically interact with stator 3350. Although discussed as a tube, tube 3362 may have any suitable cross-sectional shape, and accordingly gas bearings 3312 and 3314 may have corresponding shapes. For example, in some embodiments, tube 3362 may have a rectangular cross-section, and accordingly gas bearings 3312 and 3314 may be flat rather than annular. In some embodiments, translator 3360 includes one or more tapered regions over at least a portion of its length. For example, translator 3360 may be subject to high temperature heat transfer from reaction piston 3361. Due to the high temperatures, translator 3360 may experience thermal expansion that exceeds the maximum allowable air bearing clearance. In some embodiments, translator 3360 may include one or more tapered sections to compensate for translator thermal expansion, thereby allowing the translator and air bearing to operate over a range of operating conditions.

[0188] Bearing housings 3302 and 3304 are configured to receive bearing gas from feed lines 3303 and 3305, respectively, and form respective gas bearings 3312 and 3314. For example, with reference to the tubular geometry, each of bearing housings 3302 and 3304 may include a bearing surface disposed at a radially inward surface that is configured to interface to respective annular gas bearings 3312 and 3314. Tube 3362 may include a cylindrical bearing surface configured to interface to annular gas bearings 3312 and 3314. During operation, gas bearings 3312 and 3314 allow translator 3360 to move along axis 3390 with low, near zero, or zero friction, and prevent substantial lateral (e.g., radial) motion away from axis 3390. For example, the gas bearings 3312 and 3314 can be configured to maintain a motor air gap 3316 between the stator 3350 (e.g., the iron and copper portions thereof) and the segment 3363 during operation. It should be understood that the gas bearings 3312 and 3314 and the motor air gap 3316 can have any suitable thickness. For example, in general, the thickness is preferably as thin as possible while ensuring reliable operation. The feed lines 3303 and 3305 can include one or more pipes, fittings, hoses, air chambers, any other suitable conduits, any suitable accessories, or any combination thereof configured to deliver the bearing gas to the bearing housings 3302 and 3304, respectively. For example, in some embodiments, the feed lines 3303 and 3305 can include a slot (e.g., Fig.323208) is coupled to the corresponding bearing housings 3302 and 3304. In some embodiments, as shown, the bearing housings 3302 and 3304 include corresponding drain lines 3392 and 3394, which are configured to allow condensate removal based on gravity, pressure (e.g., via purging by pressurized bearing gas), or temperature (e.g., via condensate evaporation). The drain lines 3392 and 3394 may include, for example, valves, pipes, hoses, tubing, fittings, sensors, condensate evaporation plates, and any other suitable components for removing condensate from the bearing housings, or any combination thereof. In some embodiments, the drain lines 3392 and 3394 may be arranged on the corresponding bearing housings 3302 and 3304 to allow condensate to be removed using gravity (e.g., arranged at or near the bearing housings to allow the condensate phase to flow out when the drain port is open, with or without a bearing gas pressure above atmospheric pressure). In some embodiments, condensate from exhaust lines 3392 and 3394 is removed from the linear generator assembly or the package enclosing the linear generator assembly in a liquid state, a vapor state, or both. For example, condensate from lines 3392 and 3394 may be transferred from the linear generator assembly or the package enclosing the linear generator assembly to the environment or to a reservoir as a liquid. In another example, condensate from lines 3392 and 3394 may be transferred from the linear generator assembly or the package enclosing the linear generator assembly as vapor in exhaust gas from the linear generator assembly or the package enclosing the linear generator assembly (e.g., via evaporation).

[0189] In some embodiments, one or both of bearing housings 3302 and 3304 are rigidly attached to stator 3350. For example, rigidly attaching bearing housings 3302 and 3304 to stator 3350 can help resist lateral (e.g., radial) loads on translator 3360. In some embodiments, one or both of bearing housings 3302 and 3304 can be attached to stator 3350 via one or more flexures (e.g., having a specified stiffness in one or more directions), fixtures, mounts, fasteners, any other suitable hardware, or any combination thereof. For example, the bearing housing can be attached to a flexure that is in turn coupled to the stator (e.g., via a mount), and the flexure can allow the bearing housing to pitch, yaw, or otherwise conform to the translator while maintaining alignment. In some embodiments, one or both of bearing housings 3302 and 3304 need not be attached to stator 3350, and can be attached to a drive cylinder, a reaction cylinder, any other suitable component of a linear generator system, or any combination thereof. In some embodiments, one or both of bearing housings 3302 and 3304 may be attached to stator 3350, a driver cylinder, a reaction cylinder, any other suitable component of a linear generator system, or any combination thereof.

[0190] To illustrate, the cantilever design of the translator / air bearing system provides minimal constraints on the translator, which makes the design and manufacture of the product more tolerant to, for example, misalignment. In some embodiments, one or both of bearing housings 3302 and 3304 may be attached to a reaction cylinder or a gas spring cylinder. In some embodiments, one or both of bearing housings 3302 and 3304 may be attached to an external frame, housing, or mass of the linear generator assembly.

[0191] In some embodiments, the bearing gas is configured to exit the bearing housings 3302 and 3304 (e.g., to form respective gas bearings 3312 and 3314) in a generally radially inward direction (i.e., a streamline of the guide axis 3390). The bearing gas may flow through porous sections of the bearing housings 3302 and 3304, conduits and orifices within the bearing housings 3302 and 3304, or a combination thereof, to reach the respective gas bearings 3312 and 3314. In some embodiments, the bearing housings 3302 and 3304 may include a coating, a consumable layer, a dry film lubricant at the respective bearing surfaces to accommodate, for example, contact with the translator 3360. In some embodiments, the bearing housing extends completely and continuously around the translator in azimuth (e.g., 360°). In some embodiments, the bearing housing includes one or more bearing segments extending around the translator at an azimuthal range. For example, the bearing housing may include four bearing segments spaced ninety degrees around the translator with azimuthal gaps between the bearing segments. The bearing housing may include any suitable number of bearing segments having any suitable number of gaps and arranged in any suitable configuration about the translator.

[0192] In some embodiments, the translator 3360 may include one or more features that may engage with corresponding features of the stator 3350, the bearing housing 3302, the bearing housing 3304, or a combination thereof to substantially lock the translator 3360 in place (e.g., axially, radially, azimuthally, or a combination thereof). For example, when not in operation (e.g., during maintenance, inspection, or repair), the translator 3360 may be arranged at a suitable axial position relative to the stator 3350 and locked in place. The translator 3360 may include features (e.g., blind holes, through holes, grooves, gaps, pins, surfaces, any other suitable boss features or recessed features, or any combination thereof) that may be engaged by corresponding features to prevent the translator 3360 from shifting in one or more directions. For example, the translator 3360 may include one or more blind holes that are configured to engage with one or more pins that prevent axial movement of the translator 3360. In another example, the translator 3360 can include one or more grooves configured to engage with one or more pins that prevent axial movement of the translator 3360 .

[0193] Fig.34 A cross-sectional view of an illustrative generator assembly portion 3400 is shown according to some embodiments of the present disclosure. Generator assembly portion 3400 includes a partial assembly of an integrated linear generator system including a cylinder 3402 (e.g., a reaction cylinder), translators 3410 and 3420, stators 3417 and 3427, bearing housings 3416 and 3426, and seals 3415 and 3425. Translator 3410 includes, for example, a piston 3411 with a seal 3479, a tube 3412, and a segment 3413. Translator 3420 includes, for example, a piston 3421 with a seal 3489, a tube 3422, and a segment 3423.

[0194] For purposes of discussion, generator assembly portion 3400 will be considered to use uniflow scavenging with intake and exhaust ports on axially opposite sides (neither valved) of cylinder block 3402. Accordingly, for purposes of discussion, translator 3410 will be considered to be an intake-side translator because piston 3411 covers and uncovers intake vent port 3419. Also, for purposes of discussion, translator 3420 will be considered to be an exhaust-side translator because piston 3421 covers and uncovers exhaust vent port 3429. It should be understood that scavenging techniques other than uniflow scavenging may be used in accordance with the present disclosure.

[0195] Seals 3415 and 3425 provide a seal between the cylinder 3402 and the respective bearing housings 3416 and 3426. In some embodiments, seals 3415 and 3425 seal against the cylinder 3402 (e.g., on a radially outer surface or an axially outer surface), and also seal against any suitable surface of the respective bearing housings 3416 and 3426. For example, volumes 3418 and 3428 behind the respective pistons 3411 and 3421 (e.g., away from the reaction section 3497) may contain intake and exhaust gases, respectively. In some cases, venting the post-reaction section 3418 to atmosphere is undesirable because the intake gases therein may be at a boost pressure above atmospheric pressure, thereby causing the intake gases to flow out of the bore 3403 of the cylinder 3402 into the atmosphere (e.g., thereby potentially exhausting fuel (if the intake gases are premixed), and thereby wasting energy). Similarly, in some cases, it is undesirable to vent the post-reaction section 3428 to the atmosphere because the exhaust therein may be at a high temperature, causing the performance of nearby components (e.g., such as the stator 3427 or other components) to be affected. Because the bearing housings 3416 and 3426 provide pressurized gas to the respective gas bearings, the respective bearing gas acts as another seal, preventing gas from the bore 3403 of the cylinder 3402 or gas from the volumes 3418 and 3428 from passing through the respective gas bearings. For example, when the pressure of the intake bearing is greater than the pressure in the intake system or any pressure in the volume 3418, the intake gas is restricted or prevented from leaking to the surrounding environment (e.g., the atmosphere). Similarly, when the pressure of the exhaust bearing is greater than the pressure in the exhaust system or any pressure in the volume 3428, the exhaust in the volume 3428 is restricted or prevented from leaking to the surrounding environment (e.g., the atmosphere). Seals 3415 and 3425 may include, for example, O-rings, squeeze seals, gaskets, flanges, threads, alignment features, mating tolerances (e.g., mating joints that are nearly airtight), any other suitable components or features, or any combination thereof. Fig.36 and 37 . In some embodiments, seal 3415, seal 3425, or both may be fully or partially integrated into cylinder block 3402, respective bearing housings 3416 and 3426, or a combination thereof. For example, seals 3415 and 3425 need not comprise any rigid components or housing structures, and may comprise O-rings or gaskets between mating components. In some embodiments, seal 3415, seal 3425, or both may be configured to seal indirectly against cylinder block 3402. For example, the seal may seal against another component of the integrated linear generator system (e.g., an intake or exhaust manifold), which is sealed against cylinder block 3402. In some embodiments, generator assembly portion 3400 may include one or more ring compressors, such as Figure 2For example, a respective ring compressor may be arranged at each axial end of the cylinder 3402 for interaction with respective seals 3479 and 3489.

[0196] Fig.35 A cross-sectional view of a generator assembly portion 3500 is shown according to some embodiments of the present disclosure. The generator assembly portion 3200 is similar to Fig.34 The generator assembly portion 3400 includes an intake manifold 3598 and does not include a seal 3415. The intake manifold 3598 is sealed to the cylinder block 3402 and the bearing housing 3416, thereby acting as an intake manifold and seal (e.g., functionally similar to Fig.34 The intake port 3419 is arranged in the intake manifold 3598, wherein the intake gas flows from the intake manifold 3498 into the intake port 3419. The bearing gas or a portion thereof may flow from the bearing housing 3416 into the gas bearing and then into the intake manifold 3598. The intake manifold 3598 may be similar in shape and arrangement to Figure 23-29 of a reservoir (e.g., but port arrangement, volume, and / or other aspects may differ), Figure 23-29 The reservoir is arranged to contain gas in the rear section. In some embodiments, an exhaust manifold is included on the exhaust side of the generator assembly (e.g., similar to the intake manifold 3598 on the intake side). In some embodiments, the manifold can be paired with the cylinder block, the bearing housing, or both.

[0197] Fig.36 Demonstrating some embodiments of the present disclosure Fig.34 3480, where the seal 3479 is axially positioned in front of the inlet port 3419 (e.g., the inlet port is closed to the reaction section 3497). The bearing gas of the gas bearing 3470 can flow in both axial directions, maintaining a bearing gap 3461 (e.g., the space between the bearing housing 3416 and the translator 3410) purged with bearing gas between the bearing housing 3416 and the translator 3410 (i.e., the gas bearing). Accordingly, a mixture of intake gas (e.g., from the intake port) and bearing gas can exist in the bore 3403 (e.g., in the post-reaction section 3418) behind the piston 3411, and only the bearing gas flows out near the stator 3417 (e.g., which can be open to the atmosphere). Accordingly, the bearing housing 3416 and the seal 3415 are used to seal the gas of the bore 3403 relative to the atmosphere surrounding the cylinder 3402. Seal 3479 seals piston 3411 to cylinder 3402 and is positioned as shown. Fig.343403. The post-reaction section 3418 extends from the bearing housing 3416 to the seal 3479 and is also bounded by the seal 3415 and the cylinder 3402. As the translator 3410 translates axially, the volume of the post-reaction section 3418 changes and may undergo boundary work (e.g., compression and expansion) accordingly. The gas in the post-reaction section 3418 may include a mixture of bearing gas and intake air (e.g., together with gas from blowback and blow-by), which may flow out of the post-reaction section 3418 and into the port 3419 when the seal 3479 is in front of the port 3419 (e.g., the flow through the port 3418 may be unstable). For example, in some embodiments, the bearing gas is air, and any bearing gas mixed with the intake air in the post-reaction section 3418 is included in the intake air that undergoes reaction in the hole 3403. In the illustrative example, approximately half of the bearing gas that flows to the bearing gap 3461 may flow into the post-reaction section 3418 and undergo a reaction in the reaction section 3497. If air is the bearing gas, any air from the bearing gap 3461 that enters the reaction section 3497 will dilute the intake mixture provided to the intake port 3419 from the intake system. For illustration, a measurement of the exhaust composition from the linear generator may represent both the intake composition and the bearing gas composition. The pressure in the post-reaction section 3418 is less than the pressure of the bearing gas in the bearing gap 3461, so that at least some of the bearing gas flows from the bearing housing 3416 to the post-reaction section 3418.

[0198] Fig.37 Demonstrating some embodiments of the present disclosure Fig.34 3497, where seal 3419 is axially positioned behind the inlet port (e.g., the inlet port opens to reaction section 3497). Sections 3481 and 3480 are identical except for the axial position of translator 3410. In some embodiments, seal 3415 can be sized to affect this boundary work. For example, in some embodiments, seal 3415 is configured so that when the vent port is open (e.g., as Fig.37 As shown in FIG. 34A , the gas pressure in the post-reaction section 3418 is less than the gas pressure of the gas bearing (e.g., to ensure sufficient bearing gas flow). Fig.37 As illustratively shown in , post-reaction section 3418 may exhibit a maximum pressure when the volume of post-reaction section 3418 is minimal (e.g., at or near the BDC position of translator 3410).

[0199] For illustration, for given operating conditions, the larger the volume of the post-reaction section 3418 at BDC, the lower the volume compression ratio and volume expansion ratio of the post-reaction section 3418 during operation. Therefore, the maximum gas pressure in the post-reaction section 3418 is reduced. In some embodiments, the volume of the post-reaction section 3418 is large enough to ensure that the pressure in the post-reaction section 3418 is less than the bearing gas pressure, while also achieving as low a pressure as possible (e.g., to minimize boundary work). For example, for illustration, the peak pressure in the post-reaction section 3418 can be kept low (e.g., less than 3 bar), and the fluctuation during the stroke of the piston 3411 can be kept relatively low (e.g., less than the maximum pressure: the pressure ratio between the minimum pressure 3: 1). In some embodiments, the pressure in the post-reaction section 3418 is kept below 2 bar, with a 1.2 bar intake pressure (e.g., boost pressure). In some embodiments, the gas bearing operates with the bearing gas at a supply pressure of 6-10 bar, with the ultimate goal of achieving a pressure of 3-4 bar in the bearing gap 3461. The properties of the gas within the post-reaction section 3418 may be affected by the spatial dimensions of the translator 3410, piston 3411, cylinder 3402, seal 3415, bearing housing 3416, or their relative dimensions (e.g., gaps or voids therebetween), as well as the position of the seal 3479 and the position of the translator 3410 (e.g., TDC and BDC positions). Fig.37 , but the same features can be utilized on the exhaust side.

[0200] Fig.38An enlarged view of a section of an illustrative generator assembly portion according to some embodiments of the present disclosure is shown. A gas bearing is formed by providing a flow of bearing gas to a bearing gap 3871 purged with bearing gas between a bearing housing 3826 and a translator 3820 (i.e., a gas bearing). Accordingly, a mixture of exhaust gas and bearing gas may exist in bore 3803 behind piston 3821, and only bearing gas flows out near stator 3827 (e.g., which may be open to atmosphere). Seal 3825 is used to seal the gas of bore 3803 relative to the atmosphere. Seal 3825 is fixed relative to the movement of translator 3820 and is mounted in a seal retainer 3875. Although seal 3825 is shown as attached to retainer 3875, it may be mounted to cylinder block 3802, ring compressor 3876, any other suitable component, or any suitable combination. Seal 3889 (e.g., a sealing ring assembly) moves with the seal and seals piston 3821 to cylinder 3802. Post-reaction section 3828 extends from seal 3825 to seal 3889 and is also bounded by ring compressor 3876 and cylinder 3802. As translator 3820 translates axially, the volume of post-reaction section 3828 changes and may experience boundary work (e.g., compression and expansion) accordingly. The gas in post-reaction section 3828 may include a mixture of bearing gas and exhaust, and when seal 3889 is in front of port 3829, this mixture may flow into and out of post-reaction section 3828 and port 3829 (e.g., flow through port 3829 may be unstable). For example, in some embodiments, the bearing gas is air, and any bearing gas mixed with the exhaust in post-reaction section 3828 is included in the gas exhausted to the exhaust system and ultimately to the atmosphere. In an illustrative example, approximately half of the bearing gas that flows to the bearing gap 3871 may flow into the post-reaction section 3828. For illustration, the measurement of the exhaust composition from the linear generator may represent both the intake composition and the bearing gas composition from the intake and exhaust bearings. The pressure in the post-reaction section 3828 is less than the pressure of the bearing gas in the bearing gap 3871, so that at least some bearing gas flows from the bearing housing 3826 to the post-reaction section 3828. It may be important to maintain the pressure in the rear section 3828 below the bearing feed pressure to maintain the functionality of the bearing. When this is important, exposure to the rear section 3838 and the exhaust manifold 3879 and gas exchange between the rear section 3838 and the exhaust manifold 3879 can avoid over-pressurization of the rear section. In this embodiment, port 3877 couples the manifold 3879 post-reaction section 3828 to the exhaust manifold 3879 to limit pressure buildup in the post-reaction section 3828 (e.g., when the piston 3821 and seal 3889 are moving axially outward toward BDC). As shown, seal 3899 seals between the outer surface of cylinder 3802 and manifold 3879.In some embodiments, this can be accomplished by making the port length axially long enough so that when the piston 3821 is at BDC, the rear section 3838 is still able to exchange gases with the port and exhaust manifold 3879. In some embodiments, overpressure in the rear section 3828 can be avoided by a check valve.

[0201] The ring compressor 3876 is configured to constrain the rearrangement or disassembly of the seal 3889 during maintenance. For example, the seal 3889 may be axially positioned within the ring compressor 3876, which may be axially and / or radially moved during maintenance, inspection, installation, removal, replacement, or any other suitable activity that occurs during other non-operational periods. The spring 3878 is configured to exert an axial force (via the spring 3878) on the ring compressor 3876. Fig.38 3875) so that the ring compressor 3876 remains in contact with the cylinder body 3802. As shown, the spring 3878 pushes against the bearing housing 3826, but the spring 3878 may push against any suitable component. In some embodiments, the spring 3878 is integrated with the spring compressor 3876 and / or the retainer 3875 as a single component or a single assembly. In some embodiments, the ring compressor 3876 is mechanically attached to the cylinder body using, for example, a v-band, clamps, bolts, screws, or any other suitable mechanical attachment method or any combination. In some embodiments, the seal 3825, retainer 3875, ring compressor 3876 and spring 3878 may be integrated into one part, multiple parts, or separate parts (such as Fig.38 shown).

[0202] Fig.39A A cross-sectional view of an illustrative generator assembly portion 3900 is shown having a seal 3989 within a ring compressor 3975 according to some embodiments of the present disclosure. Fig.39A In the configuration shown in FIG. 1 , a seal (e.g., not shown, but similar to Fig.38 3925 and seal retainer 3875). A bearing gap 3971 is arranged between a bearing housing 3926 (e.g., which may be mounted to a stator 3927) and a translator 3920 (i.e., a gas bearing) and may be purged with a bearing gas. A seal 3989 (e.g., a sealing ring assembly) seals the piston 3921 to the bore 3903 of the cylinder 3902 and is positioned outwardly from the exhaust port 3929, as shown. Fig.39A As shown, the seal 3999 seals between the outer surface of the cylinder 3902 and the manifold 3979.

[0203] The ring compressor 3976 is configured to constrain rearrangement or disassembly of the seal 3989 during maintenance. For example, as shown, the seal 3989 is axially positioned within the ring compressor 3976 (e.g., during maintenance, inspection, installation, removal, replacement, or any other suitable activity occurring during other non-operational periods). As shown, the seal 3989 includes a multi-component seal forming a seal ring assembly (e.g., to accommodate wear of the seal 3989). In some exemplary embodiments, the ring compressor 3976 includes a clamshell structure that can be opened to provide access to the seal 3989. In other exemplary embodiments, the ring compressor 3976 can be composed of a single piece that can be axially moved away to provide access to the seal 3989.

[0204] Fig.39B 3976 is shown with the ring compressor 3976 removed axially outward from the seal 3989 in accordance with some embodiments of the present disclosure. Fig.39A 3900. As shown, with the ring compressor 3976 moved radially outward, the seal 3989 is partially disassembled and the various segments are removed from the piston 3921. For example, Fig.39B The configuration shown in may correspond to a time during inspection or replacement of seal 3989, inspection of a land or ring groove of piston 3921, or any other suitable time outside of operation of the generator assembly. In some embodiments, ring compressor 3976 is configured to move radially outward, axially outward, or both, in order to remove a ring segment.

[0205] In some embodiments, Figure 34-3 9 seals and bearing housings can be used with gas spring pistons and cylinders. For example, Figure 22-29 As discussed in the context of , the reservoir can act as a seal between the cylinder block and the bearing housing. In some embodiments, the seal (e.g., seal 34115, seal 3425, or both), the intake manifold 3298 can be paired, or otherwise sealed against the stator (e.g., stator 3417, stator 3427), similar to Figure 26-28 The layout shown in .

[0206] In some embodiments, translator 3920 may include one or more features (not shown) that may engage with corresponding features of the generator assembly to substantially lock translator 3920 in position (e.g., axially, radially, azimuthally, or a combination thereof). Fig.39BIn the configuration of the translator 3920, the translator 3920 can be arranged at a suitable axial position of the generator assembly (e.g., relative to the stator 3927, the bearing housing 3926, the cylinder 3902, or a feature thereof) and locked in place. The translator 3920 can include features (e.g., blind holes, through holes, grooves, gaps, pins, surfaces, any other suitable boss features or recessed features, or any combination thereof) that can be engaged by corresponding features to prevent the translator 3920 from shifting in one or more directions. For example, the translator 3920 can include one or more blind holes that are configured to engage with one or more pins that prevent axial movement of the translator 3920. In another example, the translator 3920 can include one or more grooves that are configured to engage with one or more pins that prevent axial movement of the translator 3920.

[0207] Fig.40 A cross-sectional view of a generator assembly portion 4000 having a seal 4061 is shown according to some embodiments of the present disclosure. For example, the generator assembly portion 4000 may be similar to Fig.34 side of the generator assembly portion 3400 of the generator assembly. As shown, the generator assembly portion 4000 includes a manifold 4098, and a seal 4061 that seals between the cylinder body 4002 and the bearing housing 4016. Alternatively, the seal may be configured to seal between the manifold 4098 and the bearing housing 4016 (e.g., as shown by seal 4062). The manifold 4098 is sealed to the cylinder body 4002 (e.g., using seal 4062) and directs intake air to or exhaust from port 4019 (e.g., depending on which side of the generator assembly the manifold 4098 is installed on). Port 4019 is arranged in the cylinder body 4002 within the manifold 4098. The bearing gas, or a portion thereof, may flow from the bearing housing 4016 into the gas bearing, and then into the manifold 4098. The manifold 4098 may, for example, be similar in shape and arrangement to the manifold 4098. Figure 23-28 of a reservoir (e.g., but port arrangement, volume, and / or other aspects may differ), Figure 23-28 The reservoir is arranged to contain gas in the rear section. In some embodiments, seal 4061 includes a hatch 4099, which can be removable. For example, hatch 4099 allows maintenance of the end of piston 4011, seal 4079 or pipe 4012.

[0208] Fig.41 A cross-sectional view of a generator assembly portion 4100 is shown having an intake manifold sealed against a bearing housing according to some embodiments of the present disclosure. For example, the generator assembly portion 4100 may be similar to Fig.34side of the generator assembly portion 3400. As shown, the generator assembly portion 4100 includes a manifold 4198 sealed between the cylinder 4102 and the bearing housing 4116. The manifold 4198 is sealed to the cylinder 4102 using seal 4162 and to the bearing housing 4116 using seal 4161 to direct intake air to port 4119 or exhaust air from port 4119 (e.g., depending on which side of the generator assembly the manifold 4198 is installed on). Port 4119 is arranged in the cylinder 4102 within the manifold 4198. The bearing gas or a portion thereof may flow from the bearing housing 4116 into the gas bearing and then into the manifold 4198. The manifold 4198 may be similar in shape and arrangement, for example. Figure 23-29 of a reservoir (e.g., but port arrangement, volume, and / or other aspects may differ), Figure 23-29 The reservoir is arranged to contain gas in the rear section. In some embodiments, the manifold 4198 includes a hatch 4199, which can be removable. For example, the hatch 4199 allows maintenance of the piston 4111, the seal 4179 or the end of the pipe 4112.

[0209] The translation assembly or "translator" is an actuator that couples the expansion and compression of the gas volume to an electromagnetic interaction with a stator to generate electricity. Accordingly, the translator is able to move under pressure and electromagnetic forces, generate an electromotive force (emf) in the phase of the stator (e.g., and inversely react to the emf generated by the stator), achieve a nominal linear movement path, and withstand the thermal and mechanical loads experienced during the operating cycle.

[0210] Fig.42 A side view of an illustrative translator 4200 is shown in accordance with some embodiments of the present disclosure. Fig.43 An axial end view of translator 4200 is shown in accordance with some embodiments of the present disclosure. Fig.43 4201. The axial end view of the translator 4200 is taken from direction 4201. The translator 4200 includes a tube 4212 to which pistons 4211 and 4214 are rigidly coupled (e.g., bolted, screwed, clamped, or welded together). The translator 4200 includes a section 4213, which may include features (e.g., magnets) for achieving the desired electromagnetic interaction with the stator. In some embodiments, as shown, the translator 4200 also optionally includes rails 4215 and 4216, each of which is configured to provide a position index, an anti-clocking bearing surface, or both. In some embodiments, the translator 4200 does not include rails, and provides sufficient anti-clocking stiffness in the azimuthal direction via electromagnetic interaction between the stator and the translator (e.g., as shown in FIG. 42A ). Fig.49). In some embodiments, translator 4200 or components thereof may be symmetrical about axis 4290 (e.g., including a circular shape centered at axis 4290, a fastener pattern, an arrangement of rails, and other aspects having rotational symmetry). In some embodiments, translator 4200 or components thereof need not be symmetrical about axis 4290. In some embodiments, section 4213, piston 4211, and piston 4214 may have substantially the same diameter as tubular 4212. In some embodiments, section 4213, piston 4211, and piston 4214 may have different diameters that are smaller or larger than tubular 4212. As shown, translator 4200 includes two pistons 4211 and 4214. In some embodiments, piston 4214 is configured to mate with, for example Fig. 22 The gas spring 2298 and other drive segments are in contact. Fig.42 4200 are shown as being arranged at the same axial position, but in some embodiments, the rails are included at more than one axial position or zone. Pistons 4211 and 4214 can be identical, but need not be. For example, pistons 4211 and 4214 can differ in size (e.g., diameter, axial length), features, number of seals (e.g., one ring, or more than one ring), attachments (e.g., different fasteners or fastener orientations). In another example, piston 4211 can be arranged to contact the reaction section and, accordingly, be configured to accommodate a greater temperature, greater heat flux, or both than piston 4214. As shown, translator 4200 does not include a bearing housing, a gas passage for feeding a gas bearing, or any other bearing components, except for a surface configured to interface to a bearing (e.g., a gas bearing).

[0211] Rail 4215 includes, for example, surface 4230, which may include features for position indication or indexing; and surfaces 4231 and 4232, which may include anti-clocking bearing surfaces. Anti-clocking bearing surfaces 4231 and 4232 are capable of receiving forces in the azimuthal direction (e.g., their faces are perpendicular or nearly perpendicular to the azimuthal direction). Rail 4216 includes, for example, surface 4240, which may include features for position indication or indexing; and surfaces 4241 and 4242, which may include anti-clocking bearing surfaces. In some embodiments, according to the present disclosure, the translator may include zero, one, two, or more than two rails having any suitable azimuthal or axial positioning around the translator. For example, in some embodiments, the translator may include more than one rail to provide multiple position indications (e.g., for redundancy, accuracy, symmetry, or a combination thereof). In some embodiments, translator 4200 need not include any anti-clocking rails, or any anti-clocking features. In some embodiments, in the absence of anti-clocking rails, the magnetic interaction between the translator and the stator can provide sufficient anti-clocking stiffness in the azimuthal direction. In some embodiments, in the absence of anti-clocking rails 4215 and 4216, for example, the position indexing feature can be directly attached to the translator 4200 or directly integrated into the translator 4200 (e.g., directly attached to the tube 4212 or directly integrated into the tube 4212). In some embodiments, in the absence of anti-clocking rails 4215 and 4216, for example, the position can be determined by the electromagnetic interaction between the stator and the segment 4213. In some embodiments, the surfaces 4231, 4232, 4241 and 4242 are configured to interface to corresponding anti-clocking bearings (e.g., which can include anti-clocking gas bearings). The anti-clocking bearings provide stiffness in the azimuthal direction, thereby preventing or reducing azimuthal movement of the translator. In some embodiments, surface 4230 or 4240 may include machined features for position indication or indexing, magnetic tape for position indication or indexing, optical or electrical position sensors, any other suitable features for position indication or indexing, or any combination thereof. In some embodiments, the position of the sensing translator relative to the stator may be determined by sensing the position of one or more rows of magnetic features of segments 4213 of the translator without using external position indexing features. For example, back electromotive force (emf) may be measured in one or more phase windings to determine the relative position of the stator and translator. In another example, a control signal (e.g., a pulse width modulated signal for applying current), the measured current, or both may be used to determine the relative position of the stator and translator.

[0212] In some embodiments, the translator 4200 may include one or more features that may engage with corresponding features of the generator assembly to substantially lock the translator 4200 in place (e.g., axially, radially, azimuthally, or a combination thereof). For example, when not in operation (e.g., during maintenance, inspection, or repair), the translator 4200 may be arranged at a suitable axial position of the generator assembly (e.g., relative to a stator, a bearing housing, a cylinder, or features thereof) and locked in place. The translator 4200 may include features (e.g., blind holes, through holes, grooves, gaps, pins, surfaces, any other suitable boss features or recessed features, or any combination thereof) that may be engaged by corresponding features to prevent the translator 4200 from shifting in one or more directions. For example, the translator 4200 may include one or more blind holes that are configured to engage with one or more pins that prevent axial movement of the translator 4200. In another example, the translator 4200 can include one or more grooves configured to engage with one or more pins that prevent axial movement of the translator 4200 .

[0213] Fig.44A side cross-sectional view of an illustrative translator 4400 is shown having a tapered region 4402 and an optional spacer 4470 according to some embodiments of the present disclosure. As shown, the end 4450 shown is coupled to the spacer 4470, which is coupled to the piston 4460 (e.g., having a seal 4461). Because the piston 4460 may be in contact with a relatively hot gas (e.g., from compression and / or a chemical reaction), the bearing surface 4410 may exhibit a non-uniform axial temperature field, which may result in non-uniform thermal expansion in the radial direction. In some embodiments, the translator tube 4401 may include a tapered region configured to allow non-uniform radial expansion to maintain a desired bearing clearance (e.g., gas bearing thickness). For example, the tapered region 4402 is axially arranged between a portion 4411 of the translator tube having a first outer diameter (OD1) and a second portion 4413 of the translator tube having a second outer diameter (OD2, which is greater than OD1). To illustrate, during operation, heat transfer from the power cylinder piston (e.g., the reaction section piston), heat transfer from exposure to compressed gas and post-reacted gas, or both may be reduced to the translator tube by spacer 4470 (e.g., which may include a thermal conductivity less than the thermal conductivity of piston 4460 or translator tube 4401). In some cases (e.g., without a tapered region), the magnitude of thermal expansion may cause the diameter to grow to be greater than the maximum allowable diameter to maintain sufficient gas bearing clearance. Tapered region 4402 of translator 4400 compensates for this thermal expansion, thereby allowing the gas bearing to operate under a range of operating conditions (e.g., translator tube axial temperature configurations). Tapered region 4402 may include a configuration of any suitable shape, such as a straight transition region (e.g., a cone), a piecewise linear transition region (e.g., a compound cone), a curved transition region (e.g., having any suitable curvature, continuous or segmented), any other suitable transition region, or any combination or compound thereof. In some embodiments, translator 4400 need not include spacer 4470, and piston 4461 may be attached to translator tube 4401. In some embodiments, piston may include at least two separate components: piston section 4460 and an optional collar section (not shown), which may be made of different materials with different material properties, including heat capacity. In an exemplary embodiment, the piston collar will help isolate translator 4401 further from the high temperatures of piston 4460.

[0214] According to some embodiments of the present disclosure, a low thermal conductivity material may be inserted between the end face of the translator tube 4401 and the piston 4460. For example, the low thermal conductivity material may be a sheet or ring (e.g., similar to a gasket) made of ceramic or metal. The material is configured to carry compressive loads (e.g., during operation) but to be thermally insulating (e.g., to reduce heat transfer). The insulating material may include any suitable material, such as a ceramic material or a metal. In some embodiments, the length of the piston (e.g., which is made of a more heat-resistant material) is relatively long, thereby moving the axial end face of the translator tube further away from the heat of the reaction section of the cylinder.

[0215] For example, by including a recess into one or other mating surface, a recess may be formed to help reduce heat transfer. The recess may be cut, stamped, pressed, machined, or otherwise formed in the piston, the translator tube, or both. In another example, a layer of thermal insulation material may be inserted at the joint to reduce heat transfer. The thermal insulation material may include, for example, a ceramic (e.g., a woven or fiber ceramic fabric or a gasket). In some embodiments, all or a portion of the piston includes a more heat resistant material (e.g., Inconel or ceramic). In some embodiments, increasing the axial length of the piston moves the end face of the translator tube further away from the reaction section of the cylinder, thereby producing a lower heat transfer to the translator. It should be understood that the joint between the piston and the translator tube may correspond to a reaction section piston, a driver section piston, or any other suitable piston for which it is desired to reduce heat transfer.

[0216] To illustrate, during operation, heat transfer from the power cylinder piston (e.g., the reaction section piston), heat transfer from exposure to compressed gas and post-reacted gas, or both may be reduced to the translator tube by spacer 4470 (e.g., which may include a thermal conductivity less than the thermal conductivity of piston 4460 or translator tube 4401). In some cases (e.g., without a tapered region), the magnitude of thermal expansion may cause the diameter to grow to be greater than the maximum allowable diameter to maintain sufficient gas bearing clearance. Tapered region 4402 of translator 4400 compensates for this thermal expansion, thereby allowing the gas bearing to operate under a range of operating conditions (e.g., translator tube axial temperature configurations). Tapered region 4402 may include a configuration of any suitable shape, such as a straight transition region (e.g., a conventional taper), a piecewise linear transition region (e.g., a compound taper), a curved transition region (e.g., having any suitable curvature, continuous or segmented), any other suitable transition region, or any combination or compound thereof.

[0217] In some embodiments, as shown, according to some embodiments of the present disclosure, the translator 4400 includes a recess 4471 or other recessed feature. As shown, the piston 4460 includes one or more recesses 4471 azimuthally arranged at the joint to the spacer 4470 (e.g., the joint of the translator tube 4401 if the spacer is not included). The recess 4471 reduces the contact area between the end face of the spacer 4470 or the translator tube 4401 and the mating face of the piston 4460. The recess, such as the recess 4471, can be any suitable shape, such as a recess, a groove, a blind hole, a slot, or any other suitable shape configured to reduce the contact area while still distributing the compressive load at the joint. In some embodiments, the spacer 4470, the translator tube 4401, or both include a recessed feature. For example, spacer 4470, translator tube 4401, or both may include a continuous groove that reduces the contact area between the end face of translator tube 4401 and the mating face of piston 4460. The groove may include any suitable cross-sectional shape, such as square, circular, triangular, trapezoidal, a composite shape, or any other suitable shape. In some embodiments, the groove need not be continuous and may be cut or include a recess.

[0218] In some embodiments, cooling air is directed toward the translator to cool one or more surfaces or components (e.g., Figure 2 2628 or Fig.38 For example, the air chamber can direct cooling air to the bearing surface to cool the bearing surface, thereby reducing thermal deformation or expansion.

[0219] In some embodiments, the piston may include features or components to reduce, limit, distribute, or otherwise control the adverse effects of blow-by gas downstream of the seal (e.g., on the translator tube). An example of this is Fig.44 4470 is shown in the figure. In some embodiments, the piston 4460 may include or be configured with Figure 6 In some embodiments, as shown, [Based on the slide insert Figure 6 Description].

[0220] Fig.45A side cross-sectional view of an end of an illustrative translator tube 4510 and a rail 4512 having a cantilevered section is shown according to some embodiments of the present disclosure. For example, the rail may be configured to constrain the rotational motion of the translator and / or to mount an encoder belt for position measurement. Because in some embodiments, the rail thickness may be comparable to the thickness of the translator tube, the rail may be able to increase the local stiffness of the translator tube (e.g., at least where the rail is attached). In some embodiments, if the rail is rigidly coupled to the translator tube over the entire length of the rail, the rail may experience relatively large local stresses at the end of the rail (e.g., thereby causing deformation in the bearing surface). In some embodiments, the rail is attached to the translator only along a portion of the rail, and the cantilevered section of the rail is not attached to the tube. Accordingly, the rail with the cantilevered section contributes less to the stiffness of the translator assembly and may also result in less deformation. For example, under compressive loads (e.g., caused by higher pressure acting on the translator tube), the increased stiffness provided by the fully attached rail can cause localized deformation, resulting in an out-of-round shape that is incompatible with gas bearing operation. In some embodiments, the portion of the bearing surface most affected by this deformation can be decoupled from the rail stiffness by cantilevering a portion of the rail. Fig.45 Translator tube 4510 is coupled to rail 4512 having an attached portion 4504 and a cantilevered portion 4502. Translator tube 4510 may exhibit less localized stress than a translator tube having a fully attached rail without cantilevered portion 4502. Piston 4560 is shown attached to translator tube 4510 for reference purposes.

[0221] Fig.46 A perspective view of an end of an illustrative translator tube 4601 coupled to a piston 4650 via a fastener 4605 is shown in accordance with some embodiments of the present disclosure. Translator tube 4601 is sealed to piston 4650 using a seal 4602 (e.g., an o-ring, gasket, or other sealing material). As shown, fastener 4605 is axially oriented, extending from a piston face 4651 through piston 4650 into an axial end of translator tube 4601. In some embodiments, piston 4650 may be a gas spring piston, for example.

[0222] Fig.47A perspective view of an end of an illustrative translator tube 4701 coupled to a piston 4750 via an obliquely oriented fastener 4705 is shown in accordance with some embodiments of the present disclosure. The translator tube 4701 is sealed to the piston 4750. In some embodiments, a pocket 4707 is included in the piston 4750 (e.g., as shown), the translator tube 4701, or both. As shown, the fastener 4705 is oriented at an oblique angle (e.g., relative to an axial direction) and extends through a side surface of the translator tube 4701 into the piston 4750. In some embodiments, for example, the piston 4750 can be a reaction section piston. For example, because the fastener 4705 engages the back side of the piston 4750 (e.g., away from the piston face 4708), less interstitial volume is formed, which can reduce heat transfer, reaction quenching, or both.

[0223] The obliquely oriented fasteners are oriented at a non-zero angle relative to the axial direction (e.g., not parallel or perpendicular to the axial direction). In some embodiments, the obliquely oriented fasteners allow for relatively shorter pistons in the axial direction (e.g., the piston does not have to accommodate the full length of the fastener, but only the length that extends out). In some embodiments, the obliquely oriented fasteners allow for relatively shorter piston lengths while using fasteners of a desired length (e.g., to achieve a desired bolt tension / tension when torqued), which can allow for shorter translators, shorter overall generator assembly length, or both.

[0224] In some embodiments, fasteners (e.g., fasteners oriented at an angle) may be arranged in a diametrically opposed manner (e.g., opposite in a radial direction). For example, in some such embodiments, the radial tension contribution from each fastener is balanced by the opposing fastener, thereby generating only a net axial clamping load. In some embodiments, the use of fasteners 4430 oriented at an angle relative to each other allows sufficient axial clamping load to exist on the piston joint with minimal length and mass. The piston may be attached to the translator tube using any suitable number of fasteners in any suitable arrangement and oriented at any suitable angle. For example, fasteners (e.g., fasteners oriented at an angle) may be evenly spaced around the piston in orientation. In another example, the fasteners oriented at an angle may be grouped, with each group spaced around the piston. In some embodiments, fasteners having an orientation parallel or perpendicular to the axial direction of the translator may be used. In some embodiments, fasteners having different orientations or non-uniform spacing may be used.

[0225] In some embodiments, the axial length of the piston may be selected to reduce or otherwise limit heat transfer from the piston face to the bearing surface of the translator.

[0226] Fig.48An end view of translator 4800 and additional components is shown in accordance with some embodiments of the present disclosure. Translator 4800 includes a rail 4816 that is at least partially rigidly attached to a translator tube of translator 4800. Bearing gaps 4845 and 4846 are disposed between rail 4816 and bearing housings 4841 and 4842, respectively. Bearing gaps 4845 and 4846 are configured to be filled with a bearing gas having a pressure suitable for acting as a gas bearing to maintain or otherwise constrain an azimuthal position of translator 4800 (e.g., during operation or other processes).

[0227] Bearing housings 4841 and 4842 are configured to interface to respective gas bearings, which in turn interface with respective surfaces of rail 4816. In some embodiments, bearing housings 4841 and 4842 are fixed relative to translator 4800. For example, bearing housings 4841 and 4842 may be rigidly mounted (e.g., fastened to), flexibly mounted (e.g., mounted via flexures to), or integrated (e.g., together as a single piece) to a stator, a bearing housing for constraining lateral motion of the translator (e.g., Fig.33 4 and 5. In some embodiments, bearing housings 4841 and 4842 are configured to generate respective gas bearings that provide azimuthal stiffness to the orientation of translator 4800 (e.g., against azimuthal rotation of translator 4800, thereby providing azimuthal anti-clocking). As shown, feed lines 4871 and 4872 are configured to provide bearing gas to respective bearing housings 4841 and 4842 (e.g., pressurized bearing gas supplied from a compressor or gas spring at greater than 1 atm). In some embodiments, contact bearings may be included as an alternative or in addition to gas bearings. For example, one or both of bearing housings 4841 and 4842 may or may include a bearing surface that is configured to contact rail 4816, or otherwise limit azimuthal rotation of rail 4816, while allowing rail 4816 to slide in an axial direction. In some embodiments, one or more rails, two or more gas bearing housings, or both may be provided and configured to constrain azimuthal rotation of the translator. For example, a second rail and corresponding bearing housing may be positioned 180° relative to a first rail and corresponding bearing housing. In some embodiments, rails and bearing housings may not be required. For example, another feature or component within the linear generator system (e.g., a stator) may constrain azimuthal rotation of the translator.

[0228] Position sensor 4840 is configured to sense the relative or absolute position of rail 4816 (e.g., and correspondingly the relative positions of other features of translator 4800). In some embodiments, translator 4800 is a rigid assembly (e.g., each component moves at substantially the same rate except for vibration, pressure-induced strain, or other small perturbations). In some embodiments, for example, position sensor 4840 may be an encoder head (e.g., a magnetic or optical encoder head), and rail 4816 includes a corresponding encoder tape (e.g., a magnetic or optical tape). In some embodiments, position sensor 4840 may include an encoder head (e.g., a magnetic or optical encoder head), and rail 4816 includes one or more index features to indicate position. In some embodiments, position sensor 4840 is fixed relative to translator 4800, and is therefore capable of sensing relative motion of the translator relative to a stator, a cylinder, a bearing housing, any other suitable component, or any combination thereof. For example, position sensor 4840 may be rigidly mounted (e.g., fastened), flexibly mounted (e.g., mounted via flexures), or integrated (e.g., as a single piece together) to a stator, a bearing housing, a structural frame system, any other suitable fixed component, or any combination thereof. Position sensor 4840 may include an absolute sensor, a relative sensor, an incremental sensor, any other suitable sensor type for measuring the position of translator 4800, or any combination thereof. In some embodiments, more than one rail, more than one position sensor, or both may be included. For example, a second rail and corresponding position sensor may be positioned 180° relative to a first rail and corresponding position sensor. In some embodiments, rails and position sensors may not be required. For example, another feature or component within the linear generator system (e.g., a stator) may determine the relative or absolute position of the translator. In some embodiments, bearing housings 4841 and 4842 may include features for allowing condensed liquid (e.g., condensed water from air) to drain from the bearing housings.

[0229] Fig.49 A cross-sectional view of an illustrative translator 4900 and stator 4970 and an enlarged region 4980 is shown in accordance with some embodiments of the present disclosure. Fig.494900. The cross-sectional view of is taken at an axial position, showing the translator tube 4902, the magnet assembly 4903 and the stator 4970. The magnet assembly 4903 is coupled to the translator tube 4902 (e.g., using a press fit, fastening, bonding, adhering (e.g., gluing), winding, or any other technique to form a rigid assembly). The stator 4970 may include, for example, phase windings and stator teeth (e.g., iron or steel, laminated sheets). The stator 4970 forms an air gap 4972 with the magnet assembly 4903 of the translator 4900. The magnetic resistance of the stator 4970 and the translator 4900 assembly is proportional to the size of the air gap 4972. The air gap 4972 directly affects the electromagnetic interaction of the stator 4970-translator 4900 assembly. In some embodiments, the stator 4970 may include an azimuthal gap 4971 that continues the axial length of the stator 4970 or a portion thereof, and the magnet assembly 4903 of the translator 4900 may include a corresponding azimuthal gap 4901 that continues the axial length of the magnet assembly 4903 or a portion thereof. The gaps in the stator (e.g., gap 4971) and the magnet assembly (e.g., gap 4901) may be azimuthally aligned and used during operation to maintain the azimuthal position of the magnetic assembly 4903 relative to the stator 4970 (e.g., and thus the relative position of the translator 4900 and the stator 4970). The stator 4970 and the translator 4900 may include any suitable number of corresponding gaps (e.g., the translator may include one or more gaps, and the stator may include one or more gaps) that are configured to provide anti-clocking rotation of the translator. When the corresponding gaps of the stator and the translator are azimuthally misaligned, an electromagnetic force is generated, causing the gaps to align. For example, the dashed magnet assembly in the enlarged view of region 4980 shows azimuthal misalignment and will generate a restoring force FR. In some embodiments, the one or more gaps in the stator can allow for routing through the phase windings (e.g., by providing an open path for wiring to exit the phase windings). Fig.49 4901 are shown as being approximately equal, but the azimuthal lengths of gap 4971 and gap 4901 need not be equal. For example, in some embodiments, gap 4971 and gap 4901 may have different azimuthal lengths, and their respective centerline azimuthal positions may be aligned. In some embodiments, gap 4901, gap 4971, or both may contain or consist of a dielectric material. For example, gap 4901 may be completely or partially filled with a plastic "dummy" magnet. In another example, gap 4971 may contain a plastic component for routing through the phase winding for wiring.

[0230] Fig.50A cross-sectional view of a translator 5000 and a stator 5050 is shown according to some embodiments of the present disclosure. In some embodiments, the stator 5050 may include one or more bosses 5004 to accommodate corresponding rails 5016 and optional additional rails during axial movement of the translator 5000 (e.g., when the rail 5016 is axially coincident with the stator 5050). In some embodiments, it is not necessary to maintain an air gap between the translator 5000 and the stator 5050 in one or more bosses 5004. In some embodiments, the stator includes one or more bosses to accommodate corresponding features of the translator during axial movement of the translator. For example, while a portion of the stator is configured to form an air gap with the translator (e.g., having a predetermined magnetic resistance and dimensional tolerance), other portions of the stator do not have to form an air gap with the translator. In some embodiments, the bosses 5004 are not required. For example, the combination of the height of the rails and the air gap may be sufficient so that the bosses are not required. In another example, the rail may be attached to the translator at a location such that the rail does not move within the stator.

[0231] Fig.51 A cross-sectional view of a translator 5100 and a bearing housing 5150 is shown according to some embodiments of the present disclosure. In some embodiments, the bearing housing 5150 may include one or more rails 5104 to accommodate the rail 5116 and other optional rails during axial movement of the translator 5100 (e.g., when the rail 5116 axially coincides with or otherwise overlaps the bearing housing 5150). Fig.51 As shown, the gas bearing radially disposed between the bearing housing 5150 and the translator 5100 does not extend into the one or more reliefs 5104. In some embodiments, the gas bearing radially disposed between the bearing housing 5150 and the translator 5100 does extend into the one or more reliefs 5104. In some embodiments, as shown, the bearing housing 5150 has a clamshell type construction, where two components are mated together to form a complete bearing housing 5150, as shown. Fig.51 As shown. It should be noted that for clarity and simplicity of illustration, the drawings of the present patent application are not necessarily drawn to scale and do not reflect the actual or relative size of each feature. The bearing housing can be any suitable shape, such as circular, rectangular, polygonal, curved, or any other shape, including a single segment or more than one segment. Although shown as cylindrical in the present disclosure, the translator "tube" can include any suitable cross-sectional shape or cross-sectional shape configuration along its axial length. For example, the translator tube may include an outer surface that is a bearing surface, and the bearing surface may be flat, circular, curved, segmented, or a bearing gap may be formed thereat to contain any other suitable configuration of a gas bearing. In some embodiments, the gas bearing does not have to include a relief 5104. For example, the rail may be attached to the translator at a position so that the rail does not move within the gas bearing.

[0232] The cooling system is configured to facilitate distribution of a cooling fluid to various portions of the linear generator and housing (e.g., to achieve air cooling). It should be understood that while the following description primarily refers to an air cooling system, in accordance with the present disclosure, the cooling system may distribute and condition any suitable cooling fluid (e.g., gas, liquid, or a combination thereof). Cooling may be performed to counteract energy transfer in the form of heat due to chemical processes (e.g., reaction of fuel and air), compression and expansion processes (e.g., compression work on a working fluid), mechanical processes (e.g., from friction or viscous effects), electrical processes (e.g., ohmic losses in power electronics or electrical components), or combinations thereof.

[0233] Fig.52 A system diagram of an illustrative cooling system 5200 is shown in accordance with some embodiments of the present disclosure. Illustrative cooling system 5200 includes filter 5202, piping 5203, heat exchanger 5204, fan 5206, cooling jackets 5250-5254, piping 5260, any other suitable piping (e.g., plenums, manifolds, ducts, pipes, and fittings), louvers, sensors, any other suitable components (not shown), or any suitable combination thereof.

[0234] The fan 5206 is configured to draw ambient air or another suitable gas source via a filter 5202, a line 5203, and a heat exchanger 5204 arranged upstream or downstream of the fan 5206 in any suitable order and provide the air to the cooling jackets 5250, 5251, 5252, 5253, and 5254 in any suitable arrangement. Fig.52 illustratively shown in FIG, cooling air is supplied to cooling jacket 5250 (e.g., at a cylinder housing a reaction section), from which the air enters line 5260, which distributes the gas in parallel to cooling jackets 5251 and 5252 (e.g., arranged at respective stators) and cooling jackets 5253 and 5254 (e.g., arranged at respective gas springs). As the cooling gas flows through each of the cooling jackets 5250-5254, the temperature of the cooling gas rises accordingly based on the heat load, the cooling gas mass flow, and the thermophysical properties of the cooling gas.

[0235] In some embodiments, cooling jackets 5250-5254 include air chambers that encapsulate, surround, or otherwise cover components of generator assembly 5290. In some embodiments, cooling jackets 5250-5254 include internal channels, pipes, hoses, cooling plates, fins, or other cooling features configured to cool components of generator assembly 5290. For example, in some embodiments, cooling jacket 5250 includes a cylindrical shroud azimuthally arranged around and outside the cylinder, thereby directing airflow outside the cylinder. In another example, in some embodiments, cooling jackets 5253 and 5254 each include a corresponding cylindrical shroud azimuthally arranged around and outside the corresponding gas spring cylinder, thereby directing airflow outside the corresponding gas spring cylinder. In some embodiments, cooling jackets 5251 and 5252 are integrated into the corresponding stators of generator assembly 5290. For example, the cooling jackets 5251 and 5252 may include passages within the interior of the respective stators (e.g., passages in the ferrous teeth of the stators). The cooling jackets may include manifolds, shrouds, blades, any other suitable flow-guiding features, or any combination thereof. The air provided from the fan 5206 may be directed along any suitable path in the cooling jackets 5250-5254. For example, in some embodiments, the cooling jackets 5250-5254 may all receive air from the duct 5260 in parallel. In another example, in some embodiments, some of the cooling jackets 5250-5254 may receive air in parallel with each other and in series with one or more other of the cooling jackets 5250-5254. In some embodiments, the cooling jackets 5250-5254 are arranged in series in any suitable order. For example, the order of arrangement may depend on heat loads, temperature constraints, duct routing, or a combination thereof. The linear generator system may include Fig.52 Components not shown in the drawings having dedicated cooling paths (e.g., in addition to cooling jackets 5250-5254). For example, the power electronics, the control system housing, or both may be cooled separately (e.g., using cooling jackets). In some embodiments, the air flow from cooling system 5200 may be used to maintain the power electronics and the control housing at a positive pressure relative to the environment to protect the electronic components from dust and other particles that may be detrimental to the operation of the electronic components. In some embodiments, the air flow used to cool the electronic components may be disposed of in various ways, including heating and filtering to reduce moisture and particles from the cooling air. In another example, sections of the translator may be cooled separately. In some embodiments, some of the cooling air downstream of cooling jacket 5250 may be directed away from duct 5260 for other cooling purposes (e.g., general cooling, stator cooling, bearing cooling, translator cooling).

[0236] In some embodiments, intake air from line 5203 (e.g., which is filtered) may be provided to a booster blower 5210, which increases the pressure of the intake air (e.g., air). In some embodiments, additional filters may be provided to further filter the air before entering the booster blower 5210 (e.g., finer grade filters with higher associated pressure drops). In some embodiments, the intake air is diverted to the booster blower 5210 upstream of the filter 5202, with or without additional filters. The intake air may then be directed through a heat exchanger 5204 (e.g., to cool the air after the booster blower 5210), then to other suitable components of the intake system, and then into the intake vent port of the generator assembly 5290. In some embodiments, the heat exchanger 5204 may be a gas-to-gas heat exchanger, a gas-to-liquid heat exchanger, or a combination thereof.

[0237] In some embodiments, according to the present disclosure, some or all of the cooling jackets 5250-5254 may be omitted, combined, or replaced with respect to Fig.52 In some embodiments, it may include Fig.52 For example, a cooling jacket may be included to provide cooling for one or more bearing housings, seals, manifolds, or other system components (e.g., power electronics of a control system, or processing equipment of a control system).

[0238] In some embodiments, the cooling system may be configured to cool or heat a portion of the cylinder block, bearing housing, translator, or other suitable component to help keep bearing clearance and friction low enough to minimize damage, wear, or both. For example, the bearing clearance may be selected to be as thin as possible without friction losses due to contact due to thermal effects, off-axis loads, or other disturbances.

[0239] In some embodiments, the cooling system 5200 includes a cooling subsystem for cooling the translator. For example, a compressed gas system may be included to provide compressed gas to the translator surface, thereby providing convective cooling of the translator (e.g., its bearing surface). In some embodiments, the cooling system 5200 is configured to provide slightly heated gas (e.g., heated to a temperature above ambient temperature) to one or more components. For example, the cooling system 5200 may provide slightly heated air to an electronic device (e.g., in a housing or rack) to provide moisture protection (e.g., to avoid condensation). In some embodiments, the cooling system 5200 includes one or more controllable actuators to control the flow path, thereby allowing preferential heating or cooling of components.

[0240] The frame system is configured to maintain positioning, alignment, or both, and provide rigidity against deflection for components of the integrated linear generator system. For example, fixed components of the generator assembly may be secured to the frame system to prevent relative motion during operation. In some embodiments, for example, the linear generator may operate using gas bearings and relatively tight spatial tolerances. Accordingly, maintenance of spatial arrangement and alignment in view of structural effects (e.g., component weight and mounting), cyclic pressure loads, off-axis loads, thermal expansion, and other operational influences is important for low-friction, long-term operation. For example, the frame system may provide alignment along any suitable orientation (e.g., axial, azimuthal, radial, or any combination thereof).

[0241] Fig.53 A top view of an illustrative frame system 5300 is shown according to some embodiments of the present disclosure. The illustrative frame system 5300 includes end members 5301 and 5302, an axial member 5303, any other suitable components (not shown), or any suitable combination thereof. In some embodiments, the frame system 5300 is symmetrical or partially symmetrical about an axis 5350 (e.g., the generator assembly is centered about the axis). In some embodiments, the axial member 5303 provides axial stiffness to the frame system 5300, axial alignment of components along the axis 5350 (e.g., components of the generator assembly can be mounted to the axial member 5303), or both. In some embodiments, the end members 5301 and 5302 are configured to react to forces from the corresponding gas spring cylinders. For example, the gas springs can exert large forces axially outward on the corresponding gas spring heads (e.g., particularly when the translator is outward and the gas spring is compressed). Accordingly, the end members 5301 and 5302 and the axial member 5303 can be configured to react to the corresponding axial forces. The axial member 5303 may be welded, brazed, fastened (e.g., bolted), or otherwise attached to the end members 5301 and 5302. In some embodiments, the attachment of the axial member 5303 to the end members 5301 and 5302 may be enhanced (e.g., by using connecting rods or weldments). In some embodiments, the open area between the axial member 5303 and the end members 5301 and 5302 enables relatively easy manufacture of the linear generator system by enabling the assembly to be mounted from the top into the frame system 5300 (e.g., using a crane or other lifting device).

[0242] Fig.54A side view of an illustrative frame system 5400 is shown according to some embodiments of the present disclosure. The illustrative frame system 5400 includes end members 5401 and 5402, an axial member 5403, a lateral member 5404, any other suitable components (not shown), or any suitable combination thereof. In some embodiments, the frame system 5400 provides longitudinal stiffness, lateral stiffness, azimuthal stiffness, or a combination thereof to components of the generator assembly. In some embodiments, for example, the frame system 5400 is symmetrical or partially symmetrical about an axis 5450 (e.g., the generator assembly may be centered or otherwise aligned about the axis). In some embodiments, the axial member 5403 provides axial stiffness to the frame system 5400, axial alignment of components along the axis 5450 (e.g., components of the generator assembly may be mounted to the axial member 5403), or both. In some embodiments, the lateral member 5404 provides a mounting location, lateral stiffness, axial stiffness, or any combination thereof to components of the linear generator. In some embodiments, the end members 5401 and 5402 are configured to react to forces from respective gas spring cylinders. For example, the gas springs may exert large forces axially outward on the respective gas spring heads (e.g., particularly when the translator approaches the BDC position and the gas springs are compressed). Accordingly, the end members 5401 and 5402 may be configured to react to the respective axial forces. The axial member 5403 may be welded, brazed, fastened (e.g., bolted), or otherwise attached to the end members 5401 and 5402. The lateral member 5404 may be welded, brazed, fastened (e.g., bolted), or otherwise attached to the axial member 5403. The frame system may include any suitable number of lateral members arranged at any suitable angle relative to the axial member 5403. The axial spacing of the lateral members may be sufficient to allow easy maintenance (e.g., access to key components such as bearings, pistons, rings, stators, and other components).

[0243] In some embodiments, the frame system includes one or more inlet areas arranged to accommodate components of the linear generator system. The frame system 5400 includes an inlet area 5491 for receiving the one or more components of the first linear electromagnetic machine (LEM), an inlet area 5493 for receiving the one or more components of the second LEM, an inlet area 5492 for receiving the one or more components of the cylinder, an inlet area 5490 for receiving the one or more components of the gas spring cylinder, and an inlet area 5494 for receiving the one or more components of the gas spring cylinder. The frame system 5400 includes one or more openings among the one or more components, wherein the one or more openings correspond to the inlet areas 5490-5494. The inlet areas 5490 and 5494 can be axially aligned (e.g., along the axis 5450), laterally aligned (e.g., relative to the axis 5450), or both.

[0244] Fig.55 A side view of an illustrative assembly including a frame system 5500 coupled to a generator assembly 5550 (shown in cross-section for illustrative purposes) according to some embodiments of the present disclosure is shown. The illustrative frame system 5500 includes end members 5501 and 5502, axial members 5503, lateral members 5504, any other suitable components (not shown), or any suitable combination thereof. The generator assembly 5550 can be secured to the frame system 5500. For example, components of the generator assembly 5550 (e.g., one or more cylinders, one or more stators, one or more bearing housings, one or more seals) can be aligned, attached (or both) to one or more lateral members 5504, axial members 5503, end members 5501, end members 5502, or a combination thereof. In some embodiments, the components of the generator assembly 5550 can be aligned, attached (or both) to one or more lateral members 5504, axial members 5503, end members 5501, end members 5502, or a combination thereof using mounting components, flexible components, or a combination thereof. In some embodiments, the lateral members may include openings configured to accommodate the generator assembly or its components. In some embodiments, one or more lateral members or all lateral members may include any suitable plate, support, or truss design. For example, the lateral members may include a simple beam (e.g., a welded box beam), a plate with an opening, or any other suitable design. In some embodiments, each respective lateral member may include an opening extending to the periphery of the respective lateral member, wherein the opening is configured to accommodate the generator assembly or a portion thereof. For example, in some embodiments, the opening in each lateral member may extend to the top of the lateral member, thereby allowing the generator assembly or a portion thereof to be inserted laterally from the top. In another example, a portion of the generator assembly may be inserted, installed, or removed via one or more openings in the frame system or its components.

[0245] Illustrative frame system 5500 includes mounts 5590 and 5591. In some embodiments, at least one mount may be attached to the frame. For example, a linear generator may operate within one or more frequency ranges, and at least one mount may be capable of attenuating vibrations from the linear generator. As shown, mounts 5590 and 5591 are attached to frame system 5500. In some embodiments, generator assembly 5550 operates within one or more frequency ranges, and mounts 5590 and 5591 may be capable of attenuating vibrations from the linear generator (e.g., at the one or more frequency ranges). According to some embodiments of the present disclosure, mounts 5590 and 5591 may be separate, part of a mounting system, combined, omitted, or otherwise modified. In some embodiments, one or more mounts may include rollers or wheels for transporting frame system 5500.

[0246] As shown, generator assembly 5550 includes cylinder 5551 (gas spring), bearing housing 5552, translator 5553, stator 5554, bearing housing 5555, cylinder 5556, translator 5557, bearing housing 5558, stator 5559, bearing housing 5560, and cylinder 5561 (gas spring). Bearing housings 5552 and 5555, translator 5553, and stator 5554 form a first LEM, and bearing housings 5558 and 5560, translator 5557, and stator 5559 form a second LEM. In some embodiments, the first LEM and the second LEM are aligned with each other using frame system 5500. In some embodiments, stator 5554 and stator 5559 are aligned with each other using frame system 5500, an assembly table on which frame system 5500 rests, and associated fixtures, or both. For example, a first LEM may be laterally aligned to a second LEM (e.g., to align stator bores of respective stators of the first and second LEMs). In another example, a first LEM is axially aligned to a second LEM (e.g., to set a longitudinal spacing between the first and second LEMs). In the illustrative example, when aligning components to one another using the frame system 5500, this requires arranging the components relative to one another and relative to the frame system 5500 to achieve the desired alignment. Once arranged, the associated components may be constrained or otherwise secured by the frame by means of attachment, mechanical engagement, boundaries defined by the frame system 5500, constraints imposed by one or more other components constrained or otherwise secured by the frame system 5500, by means of any other suitable mechanism for constraining or securing the components to the frame system 5500, or any combination thereof.

[0247] For example, the generator assembly 5550 may be used with Figure 2The generator assembly 5550 may be the same or similar to the generator assembly 200 of FIG. In some embodiments, the generator assembly 5550 may include one or more sub-assemblies, which may, but need not, be coupled to each other. For example, in some embodiments, the stators 5554 and 5559 (e.g., with or without corresponding bearing housings connected) may be mounted to the frame system 5500. The cylinders 5551, 5556, and 5561 may also be mounted to the frame system 5500 and aligned to the corresponding stators 5554 and 5559. Accordingly, the frame system 5500 may align or help maintain alignment of the components of the generator assembly 5550. In some embodiments, the frame system 5500 may include locating features (e.g., pins), mounting features (e.g., hole patterns, threaded posts), alignment features (e.g., adjustable mounts), or a combination thereof, which may engage with corresponding features of the generator assembly.

[0248] In an illustrative example, a linear generator may include a structural frame (e.g., frame system 5500), a cylinder (e.g., Figure 2 cylinder 202), a first LEM (eg, Figure 2 LEM 256) and a second LEM (e.g., Figure 2 The cylinder may be attached to a central region of the structural frame. The first LEM is disposed on a first longitudinal side of the cylinder and is attached to the structural frame. The second LEM is disposed on a second longitudinal side of the cylinder and is attached to the structural frame. The second longitudinal side is opposite the first longitudinal side. The second LEM is aligned to the first LEM, and the cylinder is aligned to the first LEM and the second LEM. In other embodiments, the first LEM is aligned to the second LEM, and the cylinder is aligned to the first LEM and the second LEM. For example, Figure 2 Any suitable components of the linear generator 200 may be aligned with each other using the structural frame and corresponding mounting components. In another example, the linear generator may further include a first LEM (e.g., Figure 2 The first gas spring cylinder (e.g., LEM 256) Figure 2 204), and attached to the structural frame and aligned to the second LEM (e.g., Figure 2 The second gas spring cylinder (e.g., LEM 252) Figure 2 In another example, the structural frame may include one or more openings in the top surface to allow the cylinder to be inserted into the structural frame, the first LEM to be inserted into the structural frame, and the second LEM to be inserted into the structural frame, as well as other components to be inserted into the structural frame. In another example, the cylinder (e.g., Figure 2 The cylinder 202 of the embodiment of the present invention can be provided by one or more flexible members, mounting members, or both (e.g., Figures 56-58) is attached to a structural frame (e.g., frame system 5500). In some embodiments, auxiliary equipment may be attached to the structural frame. For example, one or more power electronics systems may be mounted on the outside of the frame system, near the stator, to reduce connector length, reduce ohmic losses, and reduce electromagnetic interference (EMI). In another example, an intake system (with or without a fuel system), an exhaust system, or both may be mounted on top of the frame system. In another example, each component required for testing, operation, or both of the generator assembly may be mounted to the frame system. Frame system 5500 includes components similar to Fig.54 The mounting area of ​​the frame system 5400 is used to accommodate access to components of the generator assembly (e.g., for assembly, for maintenance, or both). As shown, the frame system 5500 includes a connecting rod 5509, which is configured to provide a compressive force on the frame system 5500 (e.g., with or without a compressive preload in a non-operating state). According to some embodiments of the present disclosure, the frame system may include one connecting rod or more than one connecting rod, but does not have to include any connecting rods. In some embodiments, the frame system (e.g., the frame system 5500) is configured to limit the stretching of the frame components to a predetermined range (e.g., less than 250 microns, less than 500 microns, less than 1 mm, less than 5 mm, or any other suitable range). For example, due to stresses generated by thermal and pressure effects, the frame system may experience strain in one or more directions. The strain can be quasi-stable (e.g., occurring over a relatively large time scale compared to cycling) or periodic or near-periodic (e.g., caused by cyclic behavior). The frame system 5500 can be configured to provide compliance (eg, axial compliance) to one or more components while maintaining a centerline of a cylinder, a stator, a bearing housing, any other suitable component, or any combination thereof.

[0249] Fig.56 An end view of an illustrative frame system 5600 is shown according to some embodiments of the present disclosure. For example, the frame system 5600 may be similar to Fig.53 The frame system 5300 and Fig.54Frame system 5400 of the embodiment of the present invention. End member 5601 includes opening 5606 (e.g., to accommodate a gas spring cylinder) and feature 5604. Illustrative feature 5604 includes a cutout disposed near the attachment location of axial member 5603, thereby reducing the stiffness between a portion of end member 5601 near opening 5606 and a portion of end member 5601 near the attachment location of axial member 5603. For example, during operation of the integrated linear generator system, the gas spring cylinder may apply an outwardly directed axial force to end member 5601 near opening 5606. Feature 5604 may allow the axial force experienced by axial member 5603 to be reduced accordingly. For example, feature 5604 may allow a portion of end member 5601 between opening 5606 and axial member 5603 to act as a flexure. In another example, feature 5604 reduces the force transmitted to axial member 5603 and thus the deflection experienced by axial member 5603. End member 5601 may experience large axial forces when the corresponding translator is at or near BDC, which may cause axial member 5603 to deflect. Feature 5604 reduces the transmission of force and thus deflection to axial member 5603. The reduced deflection of axial member 5603 can help maintain alignment of components coupled to frame system 5600. Although Fig.56 5604 need not be included.

[0250] Fig.57A cross-sectional view of an illustrative portion of an integrated linear generator system including an end member 5702, a gas spring cylinder 5703, and a head 5705 is shown according to some embodiments of the present disclosure. In some embodiments, the gas spring cylinder 5703 interfaces to an opening of the end member 5702. For example, the end member 5702 and the gas spring cylinder 5703 may include one or more corresponding locating features 5710. The locating features 5710 may include, for example, an arrangement of posts, an arrangement of pins, and an arrangement of holes, and an arrangement of slots, any other suitable features for constraining the relative position of the end member 5702 and the gas spring cylinder 5703, or any suitable combination thereof. For example, the locating features 5710 may include a corresponding bolt circle in each of the end member 5702 and the gas spring cylinder 5703, and a collection of locating pins in one component and corresponding holes in the other component. In some embodiments, the gas spring cylinder 5703 may include a flange 5706 configured to interface to the end member 5702. The flange 5706 can be disposed on the gas spring cylinder 5703 at any suitable axial position, or as part of the gas spring cylinder. For example, the flange 5706 can be connected to the head 5705 and the end piece 5702. In another example, the flange 5706 can be disposed at the distal end of the cylinder 5703 compared to the head 5705. In another example, the flange 5706 can be arranged so as not to affect the higher pressure port, the lower pressure, the cooling jacket, or a combination thereof. In some embodiments, the end piece 5702 includes a flange similar to Fig.56 One or more features of feature 5604 are used to adjust the axial stiffness of one or more portions of end member 5702. End member 5702 is configured to provide compliance (eg, axially) via feature 5604 while maintaining the centerline of the arrangement of cylinder 5703.

[0251] Fig.58A side view of an illustrative assembly 5800 including a cylinder 5802 with mounts 5820 and 5822 is shown according to an embodiment of the present disclosure. As shown, in some embodiments, a first cylinder mount 5820 and a second cylinder mount 5822 are attached to the cylinder 5802. The cylinder mounts 5820 and 5822 are attached to the cylinder and to the frame to keep the cylinder 5802 substantially fixed. The cylinder mounts 5820 and 5822 can be attached to any suitable component of the frame (e.g., an axial component, a lateral component, or both). In some embodiments, the cylinder mounts 5820 and 5822 can be configured to allow movement of the cylinder 5802 or changes in the size of the cylinder 5802 (e.g., due to thermal expansion), or include features that allow for these situations. For example, the first cylinder mount 5820 can be axially rigid, thereby constraining the mounting position of the cylinder 5802. In another example, the second cylinder mount 5822 may be axially flexible, thereby allowing the cylinder 5802 to expand and contract axially (e.g., due to thermal expansion). In some embodiments, both the first cylinder mount 5820 and the second cylinder mount 5822 are rigid in the radial direction, thereby constraining the cylinder 5802 from significant movement in the radial direction. The first cylinder mount 5820 and the second cylinder mount 5822 may be axially positioned at any suitable location (e.g., on either side of the ventilation manifolds 5810 and 5812). In an illustrative example, the first cylinder mount may be attached to the cylinder on the intake side (e.g., as shown, inside the intake ventilation manifold 5810), and the second cylinder mount may be attached to the cylinder on the exhaust side (e.g., as shown, outside the exhaust ventilation manifold 5812), with the intake end being the location of axial constraint. Intake vent ports 5811 are axially arranged within intake manifold 5810, and exhaust vent ports 5813 are axially arranged within exhaust manifold 5812. In some embodiments, block mounts 5820 are integrated into or are part of manifold 5810. In some embodiments, block mounts 5822 are integrated into or are part of manifold 5812. For example, intake side block mounts 5820 may be attached to features of intake manifold 5810 on either side of the manifold or on both sides of the manifold. In another example, exhaust side block mounts 5822 may be attached to features of exhaust manifold 5812 on either side of the manifold or on both sides of the manifold. Assembly 5800 is configured to provide compliance (e.g., axially) of cylinder 5802 while maintaining a centerline of the arrangement of cylinder 5802 (e.g., the cylinder may be aligned with one or more stator bores, one or more bearing housings, one or more other cylinders, any other suitable components, or any combination thereof).

[0252] Fig.59An illustrative cylinder block assembly 5900 having an intake manifold 5910 with a mount 5920 is shown according to some embodiments of the present disclosure. The cylinder block assembly 5900 includes a cylinder block 5902 (e.g., having an intake port 5911 and an exhaust port 5913), an intake manifold 5910, an exhaust manifold 5912, a mount 5920, a mount 5930, and a flexure 5922. The mount 5920 is configured for mounting the intake manifold 5910 to a structural frame (not shown). The mount 5930 is configured for mounting the exhaust manifold 5912 to a structural frame (not shown) via the flexure 5922. For example, the flexure 5922 can allow the cylinder block 5902 to shift axially due to thermal expansion without causing significant stress. In another example, the flexure 5922 can be relatively stiff with respect to lateral displacement of the cylinder 5902 (e.g., thereby maintaining alignment of the axis 5970 with the stator bore). The assembly 5900 is configured to provide compliance (e.g., axially) of the cylinder 5902 while maintaining a centerline of the arrangement of the cylinder 5902 (e.g., the cylinder can be aligned with one or more stator bores, one or more bearing housings, one or more other cylinders, any other suitable components, or any combination thereof).

[0253] Fig.60 A perspective view of an illustrative core 6000 is shown according to some embodiments of the present disclosure. As shown, core 6000 includes a generator assembly and frame 6050, an intake system 6010, a fuel system 6020, an exhaust system 6030, power electronics 6070 (e.g., for the intake side LEM), and power electronics 6071 (e.g., for the exhaust side). Core 6000 may include any suitable components to allow for testing, characterization, or both. For example, when installed in a complete packaging assembly (e.g., such as Fig.61 ), the core 6000 may be electrically coupled to a load bank (e.g., a collection of resistive elements), an AC grid, a DC grid, or any other electrical load for testing (e.g., to dissipate any power generated during testing) prior to testing. In some embodiments, one or more subsystems may include backup components to provide redundancy, resilience, and allow for continued operation, or to allow for a controlled shutdown in the event of failure of one or more components during operation.

[0254] Fig.61 A perspective view of an illustrative integrated linear generator system 6100 is shown, according to some embodiments of the present disclosure. Integrated linear generator system 6100 includes a housing 6150, a core 6000, and a core 6001. Fig.61Core 6000 is shown installed in housing 6150 with core 6001 partially installed / removed. Housing 6150 includes a rail system 6198 that can engage with the structural frame of either core for installation and removal of each of cores 6000 and 6001. By including distinct cores (e.g., cores 6000 and 6001), integrated linear generator system 6100 exhibits modularity and allows replacement or repair of a core rather than the entire system. According to the present disclosure, the housing can be configured to accommodate any suitable number of cores. In some embodiments, housing 6150 includes an intake device 6010 (e.g., for providing intake air to cores 6000 and 6001), an exhaust device 6120 (e.g., for receiving exhaust air from cores 6000 and 6001), and electronics 6130 (e.g., which may include a control system for controlling cores 6000 and 6001). For example, in some embodiments, the air intake device 6010 is coupled to the air intake system 6010 of the core 6000. In another example, in some embodiments, the exhaust system 6120 is coupled to the exhaust system 6030 of the core 6000. In another example, in some embodiments, the electronic device 6130 is coupled to the power electronic devices 6070 and 6071 of the core 6000.

[0255] In some embodiments, one or more components, systems, or ancillaries may be shared between cores. For example, an exhaust tuning conduit may be shared between more than one core (e.g., each core need not have a dedicated exhaust system or its dedicated tuning conduit). In some embodiments, two or more packages (e.g., similar to Fig.61 The integrated linear generator system 6100 of FIG. 6100 may communicate with each other. For example, the packages may be communicatively linked to each other via a communication network (e.g., any suitable wired or wireless network). In another example, the packages may be linked by a shared fuel system, a shared cooling system, a shared intake system, a shared exhaust system, a shared control system, a shared power electronics system, any other suitable shared system, or any combination thereof. In some embodiments, one or more cores may be synchronized with other cores to achieve operational requirements including efficiency, power, or noise.

[0256] It should be understood that the present disclosure is not limited to the embodiments described herein, and can be implemented in the context of any suitable system. In some suitable embodiments, the present disclosure is applicable to reciprocating engines and compressors. In some embodiments, the present disclosure is applicable to engines and compressors. In some embodiments, the present disclosure is applicable to combustion and reaction devices such as reciprocating engines and engines. The present disclosure is applicable to non-combustion and non-reaction devices such as reciprocating compressors and compressors. In some embodiments, the present disclosure is applicable to gas springs. In some embodiments, the present disclosure is applicable to oil-free reciprocating engines and compressors. In some embodiments, the present disclosure is applicable to oil-free engines with internal or external combustion or reaction. In some embodiments, the present disclosure is applicable to oil-free engines operating with compression ignition (e.g., homogeneous charge compression ignition, stratified charge compression ignition or other compression ignition), spark ignition or both. In some embodiments, the present disclosure is applicable to oil-free engines operating with gaseous fuels, liquid fuels or both. In some embodiments, the present disclosure is applicable to linear engines. In some embodiments, the present disclosure is applicable to engines that can be internal combustion engines with internal combustion / reaction or engines with external heating (e.g., from a heat source or external reactions such as combustion).

[0257] The above merely illustrates the principles of the present disclosure, and various modifications may be made by those skilled in the art without departing from the scope of the present disclosure. The above embodiments are presented for the purpose of illustration and not limitation. The present disclosure may also take many forms other than those explicitly described herein. Accordingly, it should be emphasized that the present disclosure is not limited to the methods, systems, and devices explicitly disclosed, but is intended to include variations and modifications thereof within the spirit of the appended claims.

Claims

1. A frame for a linear generator, the linear generator comprising two free piston assemblies, the frame comprising: Several structural components used for mounting and lateral alignment: A central cylinder arranged along the axis; two linear electromagnetic machines, each arranged on a respective side of the central cylinder along said axis; and two gas spring cylinders forming a respective gas spring, each gas spring cylinder being arranged along the axis outside the respective linear electromagnetic machine, wherein the two free piston assemblies are movable along the axis relative to a laterally aligned central cylinder and the two gas spring cylinders, and wherein at least one of the plurality of structural components is capable of counteracting an axial force caused by the respective free piston assembly resulting from a pressure in the respective gas spring.

2. The frame of claim 1, wherein the plurality of structural members provide a plurality of access areas configured to accommodate a central cylinder, the two linear electromagnetic machines, and the two gas spring cylinders.

3. The frame of claim 1 further comprising at least one connecting rod in tension to provide a compressive preload on the frame along the axis.

4. The frame according to claim 1, wherein: The two gas spring cylinders include a first cylinder and a second cylinder; The two linear electromagnetic machines include a first linear electromagnetic machine and a second linear electromagnetic machine; The first cylinder is laterally aligned with the first linear electromagnetic machine; and The second cylinder is laterally aligned with the second linear electromagnetic machine.

5. The frame according to claim 1, wherein: A first linear electromagnetic machine of the two linear electromagnetic machines comprises a first stator bore; and A second of the two linear electromagnetic machines includes a second stator aperture, wherein the first stator aperture is laterally aligned with the second stator aperture.

6. The frame of claim 1, wherein the plurality of structural components are configured to maintain a centerline for the center cylinder, the two linear electromagnetic machines, and the two gas spring cylinders.

7. The frame of claim 1, wherein the axis is a first axis, and wherein the plurality of structural components comprises: at least one axial member extending along a second axis, the second axis being parallel to the first axis; at least one lateral member secured to the at least one axial member; and A first end member is disposed at a first axial end of the at least one axial member.

8. A frame for a linear generator, the linear generator comprising two free piston assemblies, the frame comprising: at least one axial member extending along an axis parallel to a centerline of the linear generator; at least one lateral member secured to the at least one axial member; a first end member disposed at a first axial end of the at least one axial member; and a second end member disposed at a second axial end of the at least one axial member, wherein the two free piston assemblies are movable along a centerline, wherein a first gas spring cylinder is fixed to the first end member, wherein a second gas spring cylinder is fixed to the second end member, and wherein the at least one axial member is capable of counteracting an axial force generated by pressure in the first gas spring cylinder and the second gas spring cylinder.

9. The frame of claim 8, further comprising at least one connecting rod configured to be in tension to provide a compressive preload on the frame along the axis.

10. The frame of claim 8, wherein: The at least one lateral member comprises four lateral members; and The four side members, the first end member and the second end member form five inlet areas.

11. The frame of claim 8, wherein the frame is configured to mount: Center cylinder; two stators, each stator being disposed on a respective side of the central cylinder; and A first gas spring cylinder and a second gas spring cylinder, each of which is arranged outside a corresponding stator of the two stators.

12. The frame of claim 11 configured to provide radial alignment between the center cylinder, the two stators, and the first and second gas spring cylinders.

13. The frame of claim 11 configured to provide radial and azimuthal alignment between the center cylinder, the two stators, and the first and second gas spring cylinders.

14. A linear generator comprising: a frame comprising a plurality of structural components; two linear electromagnetic machines secured to the frame and laterally aligned with each other, wherein each of the two linear electromagnetic machines is arranged to interact with a respective free piston assembly; a central cylinder secured to the center of the frame between and laterally aligned with the two linear electromagnetic machines; and two gas spring cylinders secured to the frame and forming respective gas springs, each gas spring cylinder being laterally aligned with a respective one of the two linear electromagnetic machines, wherein each respective free piston assembly is movable along an axis relative to the laterally aligned central cylinder and the two gas spring cylinders, and wherein at least one of the plurality of structural components is capable of counteracting an axial force caused by the respective free piston assembly resulting from pressure in the respective gas spring.

15. The linear generator of claim 14, wherein the frame comprises one or more openings arranged on a top side, the openings being configured to allow the central cylinder to be inserted into the frame.

16. The linear generator of claim 14, wherein the frame comprises two openings arranged on a top side, the openings being configured to allow the two linear electromagnetic machines to be inserted into the frame.

17. The linear generator of claim 16, wherein the frame comprises: a first inlet region arranged to receive a first linear electromagnetic machine of the two linear electromagnetic machines; a second inlet region arranged to receive a second linear electromagnetic machine of the two linear electromagnetic machines; a third inlet region arranged to receive the central cylinder; a fourth inlet region arranged to receive a first gas spring cylinder of the two gas spring cylinders; and A fifth inlet region is arranged to accommodate a second of the two gas spring cylinders.

18. The linear generator of claim 17, wherein the first inlet region and the fifth inlet region are laterally aligned.

19. The linear generator of claim 14, wherein the frame further comprises at least one connecting rod in tension to provide a compressive preload on the frame along an axis of the frame.

20. The linear generator of claim 14, further comprising a cylinder mount secured to the frame and coupled to the central cylinder to provide axial compliance to the central cylinder.

21. A frame for a linear generator, comprising: Several structural components used for mounting and lateral alignment: A central cylinder arranged along the axis; two linear electromagnetic machines, each linear electromagnetic machine being arranged on respective opposite sides of the central cylinder along said axis; and two gas spring cylinders forming respective gas springs, each gas spring cylinder being arranged along said axis outside a respective linear electromagnetic machine; and At least one connecting rod is used to provide an axial compressive preload on at least one structural component of the plurality of structural components to counteract the force generated by the corresponding gas spring.

22. A frame for a linear generator, comprising: A plurality of structural members for mounting and laterally aligning various components, said components comprising: A central cylinder arranged along the axis; two linear electromagnetic machines including non-contact bearings supporting respective translators, each linear electromagnetic machine being disposed on respective opposite sides of the central cylinder along said axis; and Two gas spring cylinders forming a respective gas spring are each disposed outside of a respective linear electromagnetic machine along the axis, wherein the plurality of structural components are laterally aligned with the assembly such that the two respective translators are movable along the axis.

23. A linear generator system, comprising: a cylinder including a gas spring, wherein the gas spring includes a first port and a second port, each of the first port and the second port including a respective inlet port to allow ingress of gas, and wherein the gas spring is pressurized at a first pressure; a pressurized gas source in fluid communication with the gas spring using the first port and pressurized at a second pressure; and A piston assembly disposed in a cylinder and capable of moving within the cylinder, wherein: When the piston assembly is in a first position relative to the first port, the first pressure is greater than the second pressure, When the piston assembly is in a second position closer to the first port than the first position, the second pressure is greater than the first pressure, The piston assembly includes a sealing ring that forms a seal against the bore of the cylinder, the sealing ring being configured for oil-free operation, and As the sealing ring of the piston assembly moves toward the first port, gas from the pressurized gas source is delivered to the bearing housing.

24. The linear power generation system of claim 23, wherein: The first pressure is up to 2 atmospheres; The second pressure is a target pressure for pressurizing the gas spring; and Blow-by gas from the reaction section provides at least a portion of the pressurizing gas for the gas spring.

25. The linear power generating system of claim 23, further comprising at least one outlet port, wherein the at least one outlet port comprises a reed valve, wherein the reed valve acts as a passive release valve to exhaust gas from the gas spring.

26. The linear power system of claim 23, wherein the gas spring compresses the gas for distribution throughout the linear power system.

27. The linear power generating system of claim 23, further comprising a spring-loaded pressure relief valve, so that when the pressure in the gas spring exceeds a threshold, the pressure relief valve opens to release the pressure in the gas spring.

28. The linear power generating system of claim 23, further comprising an energy absorber disposed within the cylinder proximate an inboard end of the gas spring cylinder, wherein when the translator of the piston assembly travels inwardly far enough, the energy absorber deforms and absorbs kinetic energy of the piston assembly.

29. The linear power generating system of claim 23, further comprising a removable header and spacer at the outboard end of the gas spring.

30. A linear power generation system configured for oil-free operation, the linear power generation system comprising: a reservoir pressurized at a first pressure in fluid communication with a housing pressurized at a second pressure, wherein: The reservoir is in fluid communication with the cylinder through a port, and The port is in fluid communication with the housing; a fluid communication path between the reservoir and the housing, wherein: When the first pressure is greater than the second pressure, fluid is transferred from the reservoir to the housing through the fluid communication path, and When the second pressure is greater than the first pressure, fluid is communicated from the housing to the reservoir through the fluid communication path.

31. The linear power generation system of claim 30, wherein: The reservoir delivers fluid to the gas spring; and The gas spring delivers fluid to the gas bearing housing.

32. The linear power generating system of claim 30, wherein the housing comprises a bearing housing.

33. The linear power generating system of claim 30, wherein the housing comprises a gas spring housing located between an end of the cylinder and a piston face of a piston assembly moving along the cylinder.

34. The linear power generation system of claim 30, wherein blow-by gas from the reaction section provides at least a portion of the pressurizing gas for the gas spring of the housing.

35. The linear power generating system of claim 30, further comprising at least one outlet port, the at least one outlet port comprising a reed valve, wherein the reed valve acts as a passive release valve to exhaust gas from the gas spring.

36. The linear power generation system of claim 30, wherein: The piston assembly of the system includes a sealing ring that forms a seal against the bore of the cylinder; and When the sealing ring of the piston assembly approaches the port, one or more of gas from a reaction section of the piston or gas from a pressurized gas source is communicated to the bearing housing using the port.

37. The linear power generating system of claim 30, further comprising a spring-loaded pressure relief valve, so that when the pressure in the gas spring of the housing exceeds a threshold, the pressure relief valve opens to release the pressure in the gas spring.

38. The linear power generating system of claim 30, wherein the gas spring of the housing compresses the gas for distribution throughout the linear generator.

39. A system for providing pressurized gas to a gas bearing of a linear generator configured for oil-free operation, the system comprising: a port in fluid communication with a gas spring system, wherein the gas spring system includes a gas spring and a source of pressurized gas; a catheter connected to the port; as well as At least one bearing housing is in fluid communication with the gas spring system through pressurized gas delivered by the conduit, wherein the gas bearing is located between the translator and the bearing housing, and the translator is moved by the bearing housing.

40. The system of claim 39, further comprising a tank in fluid communication with the port for storing pressurized gas.

41. The system of claim 39, wherein: The pressurized gas source comprises blow-by gas from a reaction section of a piston assembly including the translator; and When the pressure of the gas within the gas spring of the gas spring system exceeds a target pressure, the blow-by gas is delivered to the tank to store the pressurized gas.

42. The system of claim 40, further comprising a regulator disposed between the tank and the at least one bearing housing, wherein the regulator modifies the pressure transmitted from the tank to the at least one bearing housing.

43. The system of claim 40, wherein the tank is configured to store pressurized gas from the pressurized gas source when the linear generator is not operating.

44. The system of claim 39, wherein the source of pressurized gas comprises a compressor.

45. The system of claim 44, wherein the compressor is powered by a battery electrically connected to a linear generator.

46. ​​The system of claim 39, wherein: The pressurized gas source comprises blow-by gas from a reaction section of a piston assembly including the translator; and When the pressure of the gas within the gas spring of the gas spring system exceeds a target pressure, blow-by gas is delivered to the gas bearing.

47. The system of claim 39, wherein: The gas spring system includes at least one outlet port including a one-way valve; and The check valve acts as a passive release valve to exhaust gas from the gas spring of the gas spring system to provide gas to the gas bearing.

48. The system of claim 47, wherein the at least one outlet port comprises a reed valve.

49. The system of claim 39, wherein: The linear generator includes a piston assembly; The piston assembly includes a sealing ring that forms a seal against the bore of the cylinder; and As the sealing ring of the piston assembly moves past the port, one or more of gas from a reaction section of the piston assembly or gas from a gas spring system is communicated to the gas bearing using the port.

50. A system comprising: A linear generator comprising: at least one gas spring, at least one power cylinder, at least one translator, at least one stator, and Multiple air intake ports; and An air intake system is provided for providing air to at least one of the plurality of intake ports and one or more cooling jackets disposed around respective portions of the linear generator.

51. The system of claim 50, wherein the air intake system includes ducting that distributes air to at least some of the one or more cooling jackets.

52. The system of claim 51 , wherein the conduits distribute air in parallel to each cooling jacket of at least some of the one or more cooling jackets.

53. The system of claim 50, wherein the one or more cooling jackets include one or more corresponding airflow directing features.

54. The system of claim 50, wherein the linear generator comprises at least one plenum interfaced with at least one of the plurality of inlet ports.

55. The system of claim 54, wherein air is mixed with fuel in the at least one air chamber.

56. The system of claim 50, wherein the air intake system further comprises a fan for drawing air into the air intake system and pushing the air into a duct that directs the air to the one or more cooling jackets.

57. The system of claim 50, wherein the air intake system further comprises a heat exchanger for cooling air prior to providing the air to the at least one of the plurality of air intake ports.

58. A linear generator comprising: at least one gas spring; at least one power cylinder; at least one translator; at least one stator; and Multiple air inlet ports, including: An air intake system provides air to at least one of the plurality of air intake ports of the linear generator and one or more cooling jackets disposed around respective portions of the linear generator.

59. The linear generator of claim 58, wherein the air intake system includes ducts that distribute air to at least some of the one or more cooling jackets.

60. The linear generator of claim 59, wherein the duct distributes air to each of the at least some of the one or more cooling jackets.

61. The linear generator of claim 58, wherein the one or more cooling jackets include one or more corresponding airflow directing features.

62. The linear generator of claim 58, wherein the linear generator comprises at least one plenum interfaced with at least one of the plurality of inlet ports.

63. The linear generator of claim 62, wherein air is mixed with fuel in the at least one air chamber.

64. The linear generator of claim 58, wherein the air intake system further comprises a fan for drawing air into the air intake system and pushing the air into a duct that directs the air to the one or more cooling jackets.

65. The linear generator of claim 58, wherein the air intake system further comprises a heat exchanger for cooling air prior to providing the air to the at least one of the plurality of air intake ports.

66. A method of cooling a linear generator, comprising: at least one gas spring; at least one power cylinder; at least one translator; at least one stator; and Multiple air intake ports; The method comprises: An air intake system is used to provide air to at least one of the plurality of air intake ports and to one or more cooling jackets.

67. The method of claim 66, further comprising distributing air to at least some of the one or more cooling jackets using at least one conduit of an air intake system.

68. The method of claim 66, further comprising causing a fan to draw air into the one or more cooling jackets.

69. The method of claim 66, further comprising mixing air with fuel in at least one plenum of a plurality of plenums that interfaces with the at least one intake port of the plurality of intake ports.

70. A linear generator comprising: a reaction section accommodated by the first cylinder; an actuator section received by the second cylinder body; a translator including a piston, wherein the translator is configured to move within a first cylinder and a second cylinder; and A limit stop is arranged between the driver section and the reaction section, wherein: The front surface of the piston contacts the driver section, and If the translator overtravels, the rear surface of the piston contacts the limit stop.

71. The linear generator of claim 70, wherein the limit stop is connected to the second cylinder.

72. A linear generator comprising: At least one cylinder, at least partially defining: expansion volume, and Compressed volume; a translator including a piston, wherein the translator is configured to move between a bottom dead center (BDC) and a top dead center (TDC) in the expansion volume and the compression volume, respectively; and A deformable feature is fixedly connected to the cylinder of the at least one cylinder and is arranged so that the translator contacts and mechanically deforms the deformable feature when the translator overtravels.

73. A translator, comprising: a tubular member including a circumferentially tapered region extending longitudinally along the length of the tubular member; and A piston interfaces with the longitudinal end of the tube.

74. The translator of claim 73 further comprising at least one spacer for interfacing the piston to a longitudinal end of the tubular.

75. The translator of claim 73 wherein the piston includes a feature that interfaces with a longitudinal end of the tubular.

76. The translator of claim 75 wherein the feature comprises a recess.

77. The translator of claim 73 wherein the tapered region comprises one or more of a conical region of tubing, a compound conical region of tubing, or a circumferentially curved tubing.

78. A linear generator comprising: a reaction section accommodated by the first cylinder; an actuator section received by the second cylinder body; and a translator configured to move in a first cylinder and a second cylinder, wherein the translator comprises: a tubular member comprising a circumferential tapered region extending longitudinally along the length of the tubular member, wherein the tapered region narrows toward the reaction zone; and A piston interfaces with the longitudinal end of the tube.

79. A housing for a linear generator system, the housing comprising: case; and At least one rail is arranged along the inner surface of the housing, wherein a structural frame of the linear generator system arranges and aligns at least one cylinder and at least one linear electromagnetic machine, and the structural frame is engageable with the at least one rail to move along the at least one rail into and out of the housing.

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