Internal combustion engine

Abstract

A gaseous fuel internal combustion engine includes an engine structure defining one or more cylinders; a piston mounted for reciprocating movement in the or each of the one or more cylinders; a crankcase; a gas pressure source configured to deliver gas along the ventilation path to remove blow-by gas from the crankcase; wherein the ventilation path includes at least one ventilation passage, the at least one ventilation passage having an opening proximate a lowest extent of the one or more cylinders.

Description

Technical Field

[0001] This teaching relates to internal combustion engines. In particular, this teaching relates to gaseous fuel internal combustion engines, such as internal combustion engines powered by hydrogen. Background Technology

[0002] To reduce emissions from internal combustion engines and potentially reduce greenhouse gases, hydrogen has been proposed as a substitute for diesel or gasoline as fuel for these engines. Additionally, other gaseous fuels, such as compressed natural gas, are known for use in internal combustion engines and can offer superior environmental benefits compared to liquid fuels like diesel and gasoline.

[0003] In internal combustion engines, it is common for air and fuel in the cylinder's combustion chamber, as well as the combustion gases formed in the combustion chamber, to leak to some extent from the combustion chamber through the piston into the engine's crankcase. This leaking gas is commonly referred to as blow-by gas.

[0004] In engines powered by gaseous fuels such as hydrogen, inadequate ventilation can lead to problems as leaked gaseous fuel components accumulate in the crankcase. This is because some gaseous fuels have a relatively high flammability range (e.g., hydrogen has a flammability concentration in air between 4% and 75%). Unless the leak is vented to reduce the concentration of gaseous fuel in the crankcase below its lower flammability limit, there is a risk that the gaseous fuel in the crankcase may ignite, potentially damaging the engine and its surrounding environment. The gaseous fuel may then ignite the lubricating oil in the crankcase, triggering further combustion.

[0005] Crankcase ventilation systems are known to be configured to vent leaks from the crankcase of a gas-fueled internal combustion engine. Typically, such systems provide a flow path for the leaks, allowing them to rise from the crankcase and through the engine to an outlet located at the top of the engine, such as the cylinder head or rocker arm cover. The leaks rise due to their high temperature; however, when the gaseous fuel has a lower density than air (e.g., hydrogen), the leaks can also buoyant.

[0006] However, leaks can accumulate in certain locations within the engine and may not be easily diluted by the ventilation system, increasing the risk of combustion in the crankcase. This risk is potentially greater in engines with higher specific output (SPE) due to increased leaks and because longer engines (such as inline six- or eight-cylinder engines) may have longer ventilation paths and therefore less effective dilution.

[0007] This teaching attempts to overcome or at least mitigate the problems of existing technologies. Summary of the Invention

[0008] A first aspect of this teaching provides a gas-fueled internal combustion engine, the engine comprising: an engine structure defining one or more cylinders; a piston mounted for reciprocating motion in or in each of the one or more cylinders; a crankcase; a gas pressure source configured to deliver gas along a ventilation path to remove leaks from the crankcase; wherein the ventilation path includes at least one ventilation passage having an opening near the lowest extent of the one or more cylinders.

[0009] Advantageously, this arrangement allows ventilation gases to be introduced into the crankcase in the area where the leak first enters, thereby diluting the leak at the point of origin and making it less likely that the ventilation gases will reach their lower flammability limit.

[0010] Optionally, the opening is at substantially the same level (height) as the lowest range of the one or more cylinders.

[0011] Advantageously, this ensures that ventilation gas is delivered directly to the location where the leak will be diluted as it leaves the cylinder.

[0012] Optionally, the engine configuration includes multiple cylinders.

[0013] Optionally, at least two of the plurality of cylinders are provided with corresponding ventilation passages, the ventilation passages having an opening at the lowest range near the corresponding cylinder.

[0014] Advantageously, by providing multiple pathways on a multi-cylinder engine, the risk of gaseous fuel reaching its ignition concentration is further reduced.

[0015] Optionally, the engine also includes a manifold arranged to connect at least two ventilation passages.

[0016] Advantageously, providing a manifold offers a convenient way to construct ventilation paths that ensure ventilation gases flow into or out of the crankcase at multiple locations.

[0017] Optionally, the manifold extends longitudinally along the engine.

[0018] Advantageously, this allows the manifold to be relatively short relative to the passage to be connected and is easy to manufacture.

[0019] Optionally, the manifold is integrated with the engine structure.

[0020] "Integration" refers to the track being formed integrally with the engine structure; for example, in embodiments where the structure is a casting, the track is part of the same cast structure as the engine. Advantageously, this simplifies the assembly of the ventilation system and reduces the risk of leaks.

[0021] The manifold can be located in the side wall of the engine structure, such as in the side wall of the cylinder block or crankcase.

[0022] Optionally, the manifold is a linear track located within the engine structure.

[0023] Advantageously, this can simplify manifold inclusion by allowing the manifold to be formed as a cast structure with suitable core or linear machining features.

[0024] Optionally, the engine also includes a gearbox, and another ventilation passage connects the ventilation path to the gearbox.

[0025] Advantageously, by providing this additional passage, any gaseous fuel in the gearbox can be diluted, thereby reducing the risk of combustion.

[0026] Optionally, the other ventilation passage connects the gearbox to the manifold.

[0027] Advantageously, this can further simplify assembly.

[0028] Optionally, the other ventilation passage is connected to the upper part of the gearbox.

[0029] Advantageously, for gaseous fuels that are lighter than air, providing a ventilation passage in this location ensures that high concentrations of fuel do not become trapped inside the gearbox.

[0030] Optionally, the at least two cylinders are arranged in a straight line.

[0031] Optionally, the wall extends downward from the bottom of the cylinder toward the crankshaft journal bearing housing between the two cylinders, thereby dividing the lower piston area of ​​the crankcase into two separate bays.

[0032] Advantageously, this arrangement helps support the crankshaft during engine operation by reacting lateral loads.

[0033] Optionally, the hole is located in the wall.

[0034] Advantageously, this allows ventilation gases to flow longitudinally along the engine from one compartment to another while maintaining the strength of the walls.

[0035] Optionally, the gas pressure source is a pump.

[0036] Optionally, the gas pressure source is configured to draw ventilation gas into the crankcase via one or more ventilation passages.

[0037] Optionally, at least one of the one or more ventilation passages includes a nozzle mounted thereon and arranged to direct ventilation gas toward the underside of the piston adjacent thereto.

[0038] Advantageously, this can help dilute leaks that may accumulate in the space under the piston.

[0039] Optionally, the cylinder or each cylinder has a displacement in the range of 0.75 liters to 1.5 liters.

[0040] Optionally, the maximum power output of the engine is in the range of 10kW to 35kW per cylinder, and optionally in the range of 12kW to 33kW per cylinder.

[0041] Optionally, the engine is a hydrogen-powered engine and includes a hydrogen fuel delivery system. Optionally, the engine may be fueled by hydrogen alone, or by a combination of hydrogen and other fuels, such as compressed natural gas.

[0042] Optionally, the engine also includes an air inlet passage upstream of the cylinder, and a hydrogen fuel delivery system injects hydrogen into the inlet passage.

[0043] Optionally, the hydrogen fuel delivery system injects hydrogen directly into the cylinder.

[0044] Optionally, the engine further includes nozzles arranged to guide an oil jet toward the piston or the underside of each piston, wherein the nozzles arranged to guide the oil jet are located on the side of the cylinder opposite to the at least one ventilation passage.

[0045] Advantageously, this can improve engine cooling, and if positioned away from ventilation passages, it can minimize the oil mist that may be generated, and thus minimize any oil residue that may need to be treated.

[0046] The second aspect of this teaching provides a work machine or genset comprising the internal combustion engine of the first aspect and a fuel tank for storing gaseous fuel (such as hydrogen), the fuel tank being in fluid communication with a fuel delivery system.

[0047] A third aspect of this teaching provides an engine structure defining a plurality of adjacent cylinders; each of the cylinders is arranged to receive a corresponding piston; a crankcase; and a wall extending downward from the bottom of the cylinder toward a crankshaft journal bearing housing for receiving the crankshaft between two adjacent cylinders, thereby dividing the lower piston region of the crankcase into two separate compartments; wherein orifices are provided in the wall to allow fluid communication between the compartments.

[0048] Advantageously, this allows leaks to flow longitudinally from one compartment to the next, thereby reducing the risk of leak concentration cavities forming in the compartments, especially if the leak is floating (e.g., the leak is hydrogen).

[0049] Optionally, the hole is located above the midpoint of the crankshaft bearing journal.

[0050] Advantageously, this location also reduces the risk of creating air leakage pools.

[0051] Optionally, the bore is closer to the bottom of the cylinder than the midpoint of the crankshaft journal bearing.

[0052] The third aspect of this teaching may also include optional features of the first aspect of this teaching.

[0053] Advantageously, this location also reduces the risk of creating air leakage pools.

[0054] Another aspect of this teaching provides a gas-fueled internal combustion engine, the gas-fueled internal combustion engine comprising: Engine structure, defining one or more cylinders; A piston is mounted for reciprocating motion in one or more cylinders or in each cylinder; Crankcase; A gas pressure source is configured to deliver gas along a ventilation path to remove leaks from the crankcase; wherein the ventilation path includes at least two discrete openings that allow ventilation gas to enter the crankcase directly, or includes at least two discrete openings that allow exhaust gas to exit directly from the crankcase.

[0055] Advantageously, this reduces the risk of high-concentration gaseous fuels accumulating in specific locations where they may reach their lower flammability limit.

[0056] The openings can be spaced apart along the longitudinal direction of the engine.

[0057] Advantageously, this can further limit the accumulation of high concentrations of gaseous fuel, especially for inline eight-cylinder, six-cylinder, and four-cylinder engines, where uniform dilution may otherwise be difficult to achieve along the length of the engine.

[0058] The opening can be connected to a public manifold.

[0059] Advantageously, providing a manifold offers a convenient way to construct ventilation paths that ensure ventilation gases flow into or out of the crankcase at multiple locations.

[0060] The gas-fueled engine may also include a gearbox, and the ventilation path may also include a separate opening that allows ventilation gases to enter the gearbox.

[0061] Advantageously, by providing this additional passage, any gaseous fuel in the gearbox can be diluted, thereby reducing the risk of combustion.

[0062] The gas-fueled engine may also include a rocker cover, and the ventilation path may also include a separate opening that allows ventilation gas to enter the rocker cover.

[0063] The gas-fueled engine may also include a rocker cover, and the ventilation path may also include a separate opening that allows exhaust gases to exit from the rocker cover. Attached Figure Description

[0064] Embodiments are now disclosed by way of example only, with reference to the accompanying drawings, in which: Figure 1 This is a schematic diagram of a gas-fueled internal combustion engine according to an embodiment of this teaching; Figure 2 yes Figure 1 A three-dimensional diagram of a gas-fueled internal combustion engine, with various auxiliary components removed; Figure 3 yes Figure 2 A reverse 3D view of the cylinder bank of an internal combustion engine; Figure 4 and Figure 5 yes Figure 3 The cylinder assembly shown is a perspective view and a side sectional view on the inclined plane WW; Figure 6 yes Figure 3 The cylinder assembly shown is a vertical sectional view on the YY plane. Figure 7 yes Figure 3 A bottom view of the cylinder assembly; Figure 8 This is a perspective view of the gas-fueled internal combustion engine of the second embodiment, in which various auxiliary components have been removed; Figure 9 yes Figure 8 A three-dimensional view of the cylinder bank of an internal combustion engine; Figure 10 yes Figure 9 An enlarged view of part A of the cylinder assembly; Figure 11 yes Figure 9 A three-dimensional view of the lower side of the cylinder assembly; Figure 12 Is Figure 9 The cross-section on the plane ZZ; and Figure 13 It includes Figure 1 A side view of an exemplary working machine with an internal combustion engine. Detailed Implementation

[0065] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of various embodiments and inventive concepts. However, those skilled in the art will understand that the teachings can be practiced without these specific details or with known equivalents having these specific details; the teachings are not limited to the described embodiments; and the teachings can be practiced in various alternative embodiments. It should also be understood that well-known methods, processes, components, and systems may not have been described in detail.

[0066] First refer to Figures 1 to 7 One embodiment includes an internal combustion engine 100.

[0067] Engine 100 is a four-stroke gas fuel IC engine configured to be powered by hydrogen, hereinafter referred to as a hydrogen fuel IC engine.

[0068] Engine 100 can be used as a working machine 10 (see...) Figure 13 The image shows a backhoe loader, but could also be a prime mover for, for example, a telescopic loader, forklift, wheeled loader, dump truck, excavator, or tractor. Such a work machine 10 is suitable for off-highway applications such as agriculture, forestry, and construction. In these industries, they are typically configured to perform tasks such as digging, load handling, harvesting, or planting crops. The engine 100 can also be used in a genset, a self-sufficient unit that provides power in an off-grid location.

[0069] Therefore, engine 100 is typically required to have certain characteristics, such as high torque output over a wide range of engine speeds, where peak torque occurs at relatively low engine speeds, unlike in light passenger vehicles, for example. In off-highway applications, this provides a “torque reserve” that allows the work machine 10 to continue operating when encountering increased loads or resistance to the work operation (e.g., an excavator encountering particularly hard clods of soil to be excavated).

[0070] In this embodiment, engine 100 has four cylinders 112. As configured, the engine has a maximum power output of approximately 129 kW; however, it should be understood that this teaching applies to engines with a wide range of power outputs. In this embodiment, the total displacement of the engine is 4.8 liters (i.e., 1.2 liters per cylinder). In engines used for off-highway applications, each cylinder can typically have a displacement between 0.75 liters and 1.5 liters. Such a displacement is relatively high compared to passenger vehicle engines, but is suitable for providing the aforementioned operating characteristics.

[0071] In this embodiment, engine 100 is fueled solely by hydrogen. In other embodiments, engine 100 may be fueled by a combination of hydrogen and other fuels, such as natural gas.

[0072] Engine 100 includes engine structure 102. Engine structure 102 includes stationary components arranged to absorb and bear the main stresses generated by the combustion of hydrogen in the engine, as well as loads generated by the movement of the piston, crankshaft, camshaft, and valve train. Engine structure 102 is also used to mount auxiliary engine components, such as pumps, turbochargers, etc. In this embodiment, engine structure 102 includes crankcase 104, cylinder head 106, cylinder bank 108, and gearbox 109.

[0073] Cylinder assembly 108 includes one or more cylinders 112; in this embodiment, there are four (see...). Figure 3 The cylinder head 106 is mounted to the cylinder bank 108 to connect to one or more cylinders 112. The cylinder head 106 includes one or more intake ports (not shown) for supplying air to each cylinder 112, and one or more exhaust ports (not shown) for discharging combustion gases from each cylinder 112. In this embodiment, the engine includes a hydrogen fuel delivery system through which hydrogen fuel can be supplied from a pressurized fuel tank 12 (…). Figure 13 It is injected directly into each cylinder 112. The rated pressure of the fuel tank 12 is typically over 35 MPa, and the hydrogen pressure can be gradually reduced before being introduced into the cylinder 112.

[0074] In other embodiments, engine 100 is a port fuel injection (PFI) engine, and one or more intake ports also supply hydrogen fuel to each cylinder 112.

[0075] In alternative embodiments (not shown), engine 100 may have more or fewer cylinder assemblies 19, such as 2, 3, 6, or 8. Additionally, in other embodiments, cylinders 112 may be oriented in a "V" shape or boxer configuration, rather than in a straight line as in the disclosed embodiments.

[0076] Engine 100 includes a valve mechanism (not shown) comprising a camshaft (not shown) and a rocker arm (not shown) arranged to open and close intake and exhaust valves (not shown), as is well known. The camshaft is mounted to cylinder bank 108. The rocker arm is mounted to cylinder head 106. Movement of the camshaft is transmitted to the rocker arm via a pushrod (not shown) extending between cylinder bank 108 and cylinder head 106. A rocker arm cover 107 is mounted to cylinder head 106 and houses the rocker arm.

[0077] Each cylinder 112 receives a piston 113, which is capable of translational movement within the cylinder 112. The space surrounded by the cylinders 112, pistons 113, and cylinder head 106 defines a combustion chamber 126. During operation of the engine 100, the translational movement of each piston 113 is converted into rotational movement of the crankshaft 111. The crankcase 104 houses the crankshaft 111.

[0078] A gearbox 109 is mounted to one or both of the cylinder bank 108 and the crankcase 104. The gearbox 109 laterally protrudes from one or both of the cylinder bank 108 and the crankcase 104. The gearbox 109 houses a gear assembly (not shown) configured to transmit rotational motion of the crankshaft to the camshaft for rocker arm operation. The gearbox 109 is in fluid communication with the crankcase 104.

[0079] Special Reference Figure 2 and Figure 3 In this embodiment, at least the cylinder head 106, cylinder bank 108, gearbox 109, and crankcase 104 of the engine structure 102 of the engine 100 are components manufactured by metal casting.

[0080] In this embodiment, the cylinder bank 108 and crankcase 104 are partially integrally formed. Specifically, the engine is bedplate type, wherein the upper portion 104a of the crankcase 104 is integrally and monolithically cast with the cylinder bank 108. The lower portion 104b is manufactured as a separate casting, wherein the joint between the upper portion 104a and the lower portion 104b is located at the midpoint of the crankshaft bearing journal. In other embodiments, the cylinder bank 108 and crankcase 104 are entirely single castings (not shown), i.e., as a single integral and monolithic material, or as two or more completely separate castings (not shown). In these cases, a separate bearing cap can be used to mount the crankshaft to the crankcase.

[0081] In this embodiment, the cylinder head 106 is manufactured as a separate casting. In other embodiments, the cylinder bank and crankcase may be separate components and / or the cylinder bank may be integrally cast with the cylinder head. The gearbox 109 is manufactured as two separate castings, which are distinct from the crankcase 104 and cylinder bank 108.

[0082] Further reference Figure 1 The engine 100 includes an intake system 115 configured to supply air to one or more cylinders 112 for combustion. In the illustrated embodiment, the intake system 115 is configured to supply air to a cylinder head 106 for delivery to the cylinders 112 via respective intake ports.

[0083] Further reference Figure 1 The intake system 115 includes an intake passage 140 (in Figure 1 (represented by double lines in the middle), the intake passage is arranged to deliver air from the upstream air filter 118 to the downstream cylinder 112.

[0084] Cylinder head 106 is mounted to cylinder bank 108. Intake manifold (not shown) forming part of intake passage 140 is mounted to cylinder head 106.

[0085] When engine 100 uses hydrogen as fuel, a spark is required to initiate combustion. Therefore, each cylinder 112 has a spark plug (not shown).

[0086] During the operation of engine 100, some gaseous fuel and air introduced into each cylinder 112, as well as combustion gases formed within cylinder 112, flow out of the combustion chamber as “leakage” along the path indicated by arrow 105, through piston 113 and into crankcase 104.

[0087] The engine 100 includes a ventilation system 110 configured to vent leaks from the crankcase 104.

[0088] Figure 1 A simplified diagram of a ventilation system 110 according to an embodiment is shown. The ventilation system 110 includes a ventilation path 116 (in... Figure 1 (Indicated by a dashed line), ventilation gas (air in this embodiment) is delivered from the intake system 115 to the crankcase 104 from the ventilation path inlet to dilute the concentration of leaks in the crankcase 104. This portion of the ventilation path 116 located upstream of the crankcase 104 is referred to as the inlet portion 125. The term "ventilation gas" is used to distinguish it from the air supplied to one or more cylinders 112 for combustion.

[0089] In this embodiment, the ventilation system 110 is configured to draw air, which is a ventilation gas, from the intake passage 140 into the ventilation path 116 at a first location 140a that defines the ventilation path inlet.

[0090] The ventilation system 110 is also configured to deliver diluted leaked gas 105 (hereinafter referred to as "exhaust gas") from the crankcase 104 to an outlet via ventilation path 116. The portion of ventilation path 116 located downstream of the crankcase 104 and gearbox 109 is referred to as outflow portion 126.

[0091] In this embodiment, the ventilation system 110 is configured to discharge exhaust gas from the crankcase 104 to a second position 140b of a defined ventilation path outlet of the intake passage 140. The second position 140b is located downstream of the first position 140a relative to the intake passage 140.

[0092] The ventilation system 110 also includes a gas pressure source 114 located within the ventilation path 116. The gas pressure source 114 is configured to deliver ventilation gas from a first position 140a to a position near the bottom of the cylinder, i.e., near the lowest range of the piston 113 during reciprocating motion, along the inflow portion 125 of the ventilation path 116.

[0093] The gas pressure source 114 is also configured to deliver a combination of ventilation gas and leakage gas 105 (which includes gaseous fuel) as exhaust gas from the crankcase 104 and gearbox 109 and along the outflow portion 126 of the ventilation path 116 to section position 140b.

[0094] It should be understood that the flow rate of the exhaust gas discharged from the crankcase 104 in the outflow portion 126 of ventilation path 116 is substantially equal to the sum of the flow rate of the leakage gas entering the crankcase via piston 113 as indicated by arrow 105 and the flow rate of the ventilation gas entering the crankcase 104 via inflow portion 125. The exhaust gas flow rate is significantly higher than that typically found in comparable diesel engines. For example, when operating at its maximum flow rate (typically when the engine is operating at its maximum load), the exhaust gas flow rate can exceed 30 liters per minute per liter of engine displacement, and may even exceed 60 liters per minute per liter of engine displacement.

[0095] In the illustrated embodiment, the gas pressure source 114 is a pump 114 or a blower. In alternative embodiments (not shown), any suitable gas pressure source can be used. For example, in some embodiments, the gas pressure source 114 may be provided by a compressor or turbine (e.g., a compressor or turbine stage of a turbocharger) in the intake system 115 / exhaust system, which is in fluid communication with the ventilation system 110.

[0096] In the illustrated embodiment, pump 114 is arranged downstream of crankcase 104, in the outflow portion 126 of ventilation path 116, and thus causes a pressure below atmospheric pressure in crankcase 104.

[0097] In an alternative embodiment (not shown), pump 114 or other gas pressure source may be configured to induce a pressure above atmospheric pressure in crankcase 104. For example, pump 114 may be located upstream of crankcase 104, in the inflow portion 125 of ventilation path 126.

[0098] In alternative embodiments, the ventilation path and / or direction may be altered.

[0099] refer to Figure 1 The ventilation system 110 includes a controller 150 configured to control the output of the pump 114 based on one or more defined operating parameters of the engine 100. The controller 150 may be part of the engine control unit (ECU) of the engine 100, or it may be a standalone controller.

[0100] Controller 150 may include any suitable circuitry to control pump 114 and follow the control methods described herein. The controller may include: control circuitry; and / or processor circuitry; and / or at least one application-specific integrated circuit (ASIC); and / or at least one field-programmable gate array (FPGA); and / or a single or multi-processor architecture; and / or a sequential / parallel architecture; and / or at least one programmable logic controller (PLC); and / or at least one microprocessor; and / or at least one microcontroller; and / or a central processing unit (CPU) to perform the described methods. Controller 150 may include associated memory, or the memory may be located locally on the controller or remotely. The memory may be non-volatile flash memory.

[0101] In this embodiment, controller 150 is configured to control pump 114 based on one or more determined operating parameters via a lookup table or graph stored in memory. The lookup table contains an appropriate number of values ​​in matrix form for load, engine speed, and corresponding setpoint flow rate. Controller 150 can be configured to interpolate to obtain the setpoint flow rate for intermediate values ​​of engine load and engine speed.

[0102] When the determined operating parameters are engine speed and engine torque, these operating parameters can be determined or obtained by the engine ECU used to operate the engine 100 and supplied to the controller 150 via signal line 152 (e.g., CAN bus as shown in the figure).

[0103] In an alternative embodiment (not shown), the controller 150 may be configured to control the pump 114 via any suitable means, such as, for example, via a physics-based model of the engine 100, or by directly sensing the hydrogen concentration in the crankcase 104 or the outflow portion. In other embodiments, the pump may be at a fixed speed, or the pump may have a fixed relationship with, for example, the engine speed.

[0104] In the illustrated embodiment, pump 114 is a variable-speed pump driven by an electric motor (e.g., a variable-speed DC electric motor) in a fixed relationship. Controller 150 is configured to control the speed of the electric motor based on one or more defined operating parameters, and thus control pump 114. For example, in an embodiment where pump 150 includes a rotating element (such as an impeller) for pumping fluid, controller 150 may be configured to control the rotational speed of the rotating element by providing a suitable control signal to the electric motor based on the impeller speed required to achieve a specific setpoint flow rate and the transmission ratio (if any) between the electric motor and the impeller. The setpoint flow rate is then determined to maintain the hydrogen concentration below a predetermined level for the main engine 100 operating parameters.

[0105] In an alternative embodiment (not shown), controller 150 may be configured to additionally or alternatively control the output of pump 114 via a mechanism other than regulating pump speed. For example, controller 150 may be configured to control the position of one or more rotating blades or vanes within pump 114, or the position of the output valve of pump 114. In such an embodiment, pump 114 may not be a variable speed pump.

[0106] Now for special reference Figures 4 to 7 A portion of the ventilation path 116 within the engine structure 102 will be discussed in more detail. In this embodiment, the ventilation path 116 provides multiple inlets into the crankcase 104.

[0107] In this embodiment, ventilation gases enter the side of the engine cylinder bank 108 via a suitable interface, such as a spigot 160. The spigot may be integrally cast with the engine structure 102 or connected by welding, forging, or the like. The spigot 160 communicates with a manifold 162 in the form of a rail, which extends longitudinally above the upper portion 104a of the crankcase 104 within the engine cylinder bank. The manifold 162 is isolated from oil passages 163 within the structure 102 that allow oil to flow downwards from the cylinder head into the crankcase 104, and the manifold is also isolated from cooling passages (not shown) in the engine 100 through which coolant (not shown) flows before circulating to a heat exchanger (not shown), as is well known.

[0108] Multiple ventilation passages 164 extend generally downward from manifold 162 and terminate in an opening in the upper part of crankcase 104a to define ventilation gas inlets. Ventilation passages 164 allow ventilation gas to be distributed from manifold 162 into the interior space 165 of crankcase 104.

[0109] In this embodiment, manifold 162 and ventilation passage 164 are formed using a core in a casting. In other embodiments, manifold 162 and / or ventilation passage 164 may be formed by machining a casting or by a combination of core and machining. In alternative embodiments, the manifold may be separable from engine structure 102 and may be, for example, a rail or other container mounted to the outside of cylinder bank 108 or crankcase 104.

[0110] As in Figure 6 and Figure 7 As can be most clearly seen, the lowest extent of each cylinder 112 is defined by a generally downward-facing, generally horizontal wall 166. This wall 166 also defines the boundary between the cylinder bank 108 and the upper part of the crankcase 104a. It also represents the approximate lowest range of motion of each piston 113 during operation of the engine 100 (the piston skirt may be exposed to a certain extent below the wall at bottom dead center). Thus, any leakage 105 that can pass between the piston 113 and the wall of the cylinder 112 first enters the crankcase 104, near the bottom of the cylinder 112, adjacent to the horizontal wall 166, and therefore adjacent to the opening of the ventilation passage 164.

[0111] As can be seen, in this embodiment, one ventilation passage is provided for cylinder one (located at the front of engine 100), and two ventilation passages are provided for each of cylinders two, three, and four. This is because other features of structure 102 result in a lack of space to provide another passage 164 for cylinder one 112. However, in this embodiment, the cross-sectional area of ​​the ventilation passage 164 for cylinder one is twice the cross-sectional area of ​​the ventilation passages for cylinders two, three, and four, such that the ventilation gas flow from each cylinder is substantially equal. In other embodiments, the number of ventilation passages 164 for each cylinder 112 may be equal, for example, two or one ventilation passage may be provided for all cylinders 112, or adjustments may be made as needed.

[0112] Additionally, the rear end 168 of manifold 162 is in fluid communication with the interior of gearbox 109, allowing ventilation gas to flow from manifold 162 into the gearbox and dilute any leaks 105 that may enter gearbox 109. The advantageous location of manifold 162 is that it can enter the gearbox near the upper end of gearbox 109, ensuring that any floating leaks 105 (especially hydrogen) are completely diluted within the gearbox.

[0113] Manifold 162 provides a location for mounting the rupture disc 176 at a port on the side of the engine, which can serve as an alternative pipe connection point for the inflow section 125. In the event of a leaky combustion, the rupture disc 176 can be used as a priority pressure relief location to minimize the risk of damage to other engine components.

[0114] Generally U-shaped nozzles 178, forming part of a separate oil circulation system for engine 100, are mounted to ports in the wall 166 adjacent to each cylinder 112 and direct oil jets toward the underside of each piston 113 to cool the piston. These nozzles 178 are located on the side of cylinder 112 opposite to ventilation passage 164. This can be advantageous because the spacing reduces the risk of ventilation gas impacting the oil jet and generating oil mist. Furthermore, this can reduce the amount of oil carried in the exhaust gas, which may subsequently need to be separated before the exhaust gas is introduced into intake passage 140.

[0115] refer to Figure 4 and Figure 6 As can be seen, walls 170 extend downwards parallel to the axis Y from the bottom of cylinder bank 108 between adjacent cylinders 112 into the upper crankshaft region 104a, thus forming discrete compartments corresponding to each cylinder. These walls 170 are part of the casting of the upper crankshaft region 104a and define a seat 172 for the crankshaft journal bearing at its lowest point. Thus, they support the crankshaft 111 during operation of the engine 100 when an eccentric load is applied to it due to the reciprocating motion of the piston 113. Another seat is provided by the lower portion 104b of the crankcase 104.

[0116] However, such a wall 170 may restrict the circulation of ventilation gas and allow the formation of concentrated cavities for leakage 105. Therefore, in this embodiment, holes 174 are provided in the wall 170 to facilitate the circulation of ventilation gas along the crankcase parallel to the axis X. In this embodiment, three holes 174 are provided in each wall, but it should be understood that their number, size, shape, and position can be adjusted in other embodiments to maintain the strength of the wall while allowing appropriate gas flow.

[0117] In this embodiment, the hole 174 is cast into the wall 170, but in other embodiments, it may alternatively be machined into the wall as a continuous casting.

[0118] In this embodiment, when the ventilation system is operating, pump 114 draws air as ventilation gas from intake passage 140 at point 140a, enters manifold 162 along inflow portion 125 of ventilation path 116, and then flows into the interior space 165 of crankcase 104 via ventilation passage 164. Therefore, any leaks 105 entering the crankcase interior 165 are diluted upon entry and can be kept below the lower flammability limit. Additionally, the ventilation gas is introduced into gearbox 109 via rear end 168 of manifold 162, further diluting any leaks 105 that might otherwise accumulate there. In this embodiment, pump 114 draws exhaust gas from rocker cap 107 on top of the engine, which enters the rocker cap upwards from the crankcase via drain passage 163. The exhaust gas is reintroduced into the intake passage at point 140b, downstream of point 140a.

[0119] This configuration of the ventilation system 110 dilutes and flushes hydrogen and / or other gaseous fuels from almost all components of the engine 100, counteracting the tendency of hydrogen or other gaseous fuels to accumulate in high-concentration cavities, such as under the piston and / or at the top of the engine (assuming it is mounted in a normal upright orientation), due to their natural buoyancy. It also creates negative pressure in the crankcase 104 and other internal spaces of the engine 100.

[0120] However, in other embodiments, the flow direction can be reversed, such that exhaust gases are drawn from the crankcase 104 via ventilation passage 164 and manifold 162, where ventilation gases have already been introduced to other parts of the engine 100 (e.g., rocker arm cover 107) and / or positive pressure can be generated in the crankcase 104. Furthermore, instead of connecting an external pipe to the sleeve 160, a passage can be formed in the engine structure 102 that connects to the manifold 162, allowing the use of a shorter pipe that travels from the intake passage 140.

[0121] Figures 8 to 12 A second embodiment of this teaching is shown. Similar features in this embodiment are indicated by the same reference numerals, but with the prefix "2" instead of "1". The differences between the two embodiments are discussed in detail only.

[0122] The engine 200 of this embodiment has six cylinders in a row, but has the same basic structure as the engine 200.

[0123] In this embodiment, outside the engine 100 and Figure 8The manifold 262, schematically shown, supplies ventilation gas to three locations: the rocker arm cover 207 at the top of the engine, and two ventilation passages 264 at the lowest points near the two cylinders 212. The first ventilation passage 264 is located at the front of the upper crankcase 204a, adjacent to cylinder 212, while the second ventilation passage 264 reuses the existing turbine drain port, which enters the upper crankcase portion of cylinder 212 near the side of the engine 200.

[0124] from Figure 11 and Figure 12 As can be seen, hole 274 is provided in the wall 170 between cylinders in a manner similar to that in the first embodiment. However, in this embodiment, as an adaptation to the existing engine structure 202, hole 274 is machined from below at a certain angle after casting.

[0125] Exhaust gases are removed from the gearbox (not shown) at the rear of the engine 100.

[0126] The combination of inlets and outlets in these locations, along with the holes 274 in the walls, allows ventilation gas to flow from the front to the rear of the engine below each cylinder 212 without allowing leaks 105 to accumulate at the location below the piston. Additionally, ventilation gas introduced at the top of the rocker cap 207 dilutes any leaks that accumulate in the cavity at the top of the engine 200, and the outlet in the gearbox draws in ventilation gas downwards and toward the rear of the engine 200, where it meets the ventilation gas introduced through ventilation passage 264.

[0127] Furthermore, as described above, by utilizing CCV systems 110 and 210 that adjust the ventilation rate according to the amount of leaking hydrogen, it is ensured that the concentration of gaseous fuel remains low under all engine operating conditions. In this embodiment, the ventilation system is configured to maintain the hydrogen concentration below 4%, optionally below 3%, for example below 2%, i.e., below its lower flammability limit.

[0128] The above description of one or more embodiments is by way of example only, and it should be understood that variations may be made without departing from the scope of protection provided by the appended claims. For example, although a near-vertical ventilation passage 164 is shown in the first embodiment, it should be understood that in other embodiments, the opening of the passage may point in other directions, such as horizontal or near-horizontal, and the position of the manifold may be adjusted accordingly. In some embodiments, nozzles may be fitted into passages 164, 264 in the engine structure to extend the passage, for example, to guide ventilation gas upward from below the piston.

Claims

1. A gas-fueled internal combustion engine, comprising: Engine structure, defining one or more cylinders; A piston is mounted for reciprocating motion in one or more cylinders or in each cylinder; Crankcase; A gas pressure source is configured to deliver gas along a ventilation path to remove leaks from the crankcase; wherein the ventilation path includes at least one ventilation passage having an opening at a minimum extent near the one or more cylinders.

2. The engine according to claim 1, wherein, The opening is at substantially the same level as the lowest range of the one or more cylinders.

3. The engine according to claim 1 or 2, wherein, The engine structure includes multiple cylinders.

4. The engine according to claim 3, wherein, At least two of the plurality of cylinders are provided with corresponding ventilation passages, the ventilation passages having an opening at the lowest point near the corresponding cylinder.

5. The engine of claim 4 further includes a manifold arranged to connect at least two ventilation passages.

6. The engine according to claim 5, wherein, The manifold extends longitudinally along the engine.

7. The engine according to claim 5 or 6, wherein, The manifold is integrated with the engine structure.

8. The engine according to claim 7, wherein, The manifold is a linear track disposed within the engine structure.

9. The engine according to any one of the preceding claims, wherein, The engine also includes a gearbox, and another ventilation passage connects the ventilation path to the gearbox.

10. The engine according to claim 9, wherein, The other ventilation passage connects the gearbox to the manifold.

11. The engine according to claim 9 or 10, wherein, The other ventilation passage is connected to the upper part of the gearbox.

12. The engine according to claim 3 or any one of claims 4 to 11 when dependent on claim 3, wherein, The at least two cylinders are arranged in a straight line.

13. The engine according to claim 12, wherein, The wall extends downward from the bottom of the two cylinders toward the crankshaft journal bearing housing between them, thereby dividing the lower piston region of the crankcase into two separate compartments.

14. The engine according to claim 13, wherein, The hole is provided in the wall.

15. The engine according to any one of the preceding claims, wherein, The gas pressure source is a pump.

16. The engine according to any one of the preceding claims, wherein, The gas pressure source is configured to draw ventilation gas into the crankcase via the one or more ventilation passages.

17. The engine according to any one of the preceding claims, wherein, At least one of the one or more ventilation passages includes an upwardly mounted nozzle, the nozzle being arranged to direct ventilation gas toward the underside of the piston adjacent to it.

18. The engine according to any one of the preceding claims, wherein, The cylinder or each cylinder has a displacement in the range of 0.75 liters to 1.5 liters.

19. The engine of claim 18, wherein the maximum power output of the engine is in the range of 10 kW to 35 kW per cylinder, optionally in the range of 12 kW to 33 kW per cylinder.

20. The engine according to any one of the preceding claims, wherein, The engine is a hydrogen-powered engine and includes a hydrogen fuel delivery system.

21. The engine of claim 20, further comprising an air inlet passage located upstream of the cylinder, and the hydrogen fuel delivery system injecting hydrogen into the inlet passage.

22. The engine according to claim 20, wherein, The hydrogen fuel delivery system injects hydrogen directly into the cylinder.

23. The engine according to any one of the preceding claims further includes a nozzle arranged to guide an oil jet toward the piston or the underside of each piston, optionally, wherein, The nozzle, which is arranged to guide the oil jet, is located on the side of the cylinder opposite to the at least one ventilation passage.

24. A working machine or generator set comprising an internal combustion engine according to any one of claims 1 to 23 and a fuel tank for storing gaseous fuel, such as hydrogen, the fuel tank being in fluid communication with a fuel delivery system.

25. An engine configuration defining a plurality of adjacent cylinders; each of the cylinders being arranged to receive a corresponding piston; Crankcase; A wall extends downward from the bottom of two adjacent cylinders toward the crankshaft journal bearing housing for receiving the crankshaft, thereby dividing the lower piston region of the crankcase into two separate compartments. in, The holes are provided in the wall to allow fluid communication between the compartments.

26. The engine structure according to claim 25, wherein, The hole is located above the midpoint of the crankshaft bearing journal.

27. The engine structure according to claim 26, wherein, The hole is closer to the bottom of the cylinder than to the midpoint of the crankshaft journal bearing.

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