Cam phaser for internal combustion engine

Abstract

An internal combustion engine includes: a plurality of pistons housed in respective ones of a plurality of cylinders; an intake system for providing air to the plurality of cylinders through respective ones of a plurality of intake valves; and an exhaust system for releasing exhaust gas from the plurality of cylinders through respective ones of a plurality of exhaust valves. A cam phaser is provided that is controllable to advance or delay exhaust valve opening / closing timing by a crank angle of up to 90 degrees.

Description

Technical Field

[0001] The present invention relates to internal combustion engines and, more particularly, but not exclusively, to cam phasers for internal combustion engines. Background Art

[0002] Internal combustion engines may be controlled in an attempt to achieve certain performance outputs required for engine braking during operation, and / or in order to maintain a desired operating temperature for an aftertreatment subsystem. For example, thermal management of the aftertreatment system and / or engine temperature may provide operational benefits such as a more efficient combustion process, more efficient aftertreatment device operation, and fuel economy. Accordingly, various engine braking and thermal management systems have been developed to better achieve these performance outputs.

[0003] Turbochargers with variable geometry (VG) inlets have been used to increase exhaust temperatures. However, VG turbochargers are more expensive than turbochargers with wastegates. Exhaust heaters may also be used, but require additional cost and a generator to produce the energy to run the heater. Exhaust throttles for engine braking and thermal management also require additional cost and can present reliability issues over time. Other strategies such as hydrocarbon (HC) dosing and cylinder deactivation have been used for thermal management of aftertreatment systems but can be more effective. These thermal management and engine braking strategies may require multiple additional components to implement, increasing the cost and complexity of the system. Therefore, there is a constant need to make further efforts in this area of ​​technology. Summary of the invention

[0004] Certain embodiments of the present application include unique systems, methods, and apparatuses related to internal combustion engines including one or more cam phasers. One or more cam phasers can be adjusted or controlled to increase and / or decrease engine heat output, thereby providing thermal management of one or more aftertreatment components. One or more cam phasers can also or alternatively be adjusted or controlled to increase and / or decrease engine braking power. Other embodiments include unique apparatus, devices, systems, and methods related to cam phasers and internal combustion engines using the same.

[0005] In one embodiment, a cam phaser for advancing and retarding an exhaust valve of an internal combustion engine is disclosed. The cam phaser includes a rotor including a hub and a plurality of blades. The plurality of blades extend radially outward from the hub. The cam phaser also includes a stator including a rim and a plurality of lugs. The plurality of lugs extend radially inward from the rim. The rotor is positioned in the stator so that each of the plurality of blades is positioned between a corresponding pair of lugs in the plurality of lugs. Each blade of the rotor is positioned adjacent to a first lug in the corresponding pair of lugs to fully retard the exhaust valve. Each blade of the rotor is positioned adjacent to a second lug in the corresponding pair of lugs to fully advance the exhaust valve. The blades of the rotor rotate 45 degrees from a fully retarded position to a fully advanced position.

[0006] In one embodiment, a method for braking an internal combustion engine includes receiving a charge flow into a plurality of cylinders of the internal combustion engine to generate exhaust gas by combusting fuel provided to at least a portion of the plurality of cylinders. In response to an engine braking request, a phase angle of a camshaft that controls exhaust valve opening / closing timing and intake valve opening / closing timing of one or more of the plurality of cylinders is changed to increase braking power of the engine.

[0007] In one embodiment, a method for thermal management of an aftertreatment device or an internal combustion engine includes generating exhaust gas by combusting fuel received in an air flow entering at least a portion of a plurality of cylinders of the internal combustion engine. In response to a thermal management condition of the engine or the aftertreatment device, the method includes changing a phase angle of an exhaust camshaft that controls exhaust valve opening / closing timing by more than 80 crank angle degrees.

[0008] This summary is provided to introduce some concepts further described below in illustrative embodiments. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as ancillary content to limit the scope of the claimed subject matter. Additional embodiments, forms, objects, features, advantages, aspects and benefits will become apparent from the following description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of one embodiment of an internal combustion engine including a cam phaser.

[0010] Figure 2 yes Figure 1 A diagrammatic schematic diagram of one embodiment of a cylinder and cam phaser of an internal combustion engine system.

[0011] Figure 3 is connected to the camshaft for opening and closing Figure 2 A perspective view of an implementation of a cam phaser for an intake valve or an exhaust valve of a cylinder in FIG.

[0012] Figure 4 is an exploded perspective view of an embodiment of an exhaust cam phaser.

[0013] Figure 5 yes Figure 4 A perspective view of the exhaust cam phaser.

[0014] Figure 6 yes Figure 4 A rear elevation view of the rotor and stator assembly of a cam phaser.

[0015] Figure 7 Is mounted to the drive gear Figure 6 Front elevation view of the rotor and stator assembly.

[0016] Figure 8 is an elevation view of an embodiment of a blade or rotor seal.

[0017] Fig. 9 is a perspective view of an embodiment of a rotor and stator assembly for an intake cam phaser.

[0018] Fig.10 is a schematic diagram of a portion of a fluid flow path for providing control fluid to control a cam phaser.

[0019] Fig.11 is a schematic diagram showing control fluid flow paths to the rotor and stator assemblies of the intake and exhaust camshafts.

[0020] Fig.12 is a flow chart of a procedure according to an embodiment of the present disclosure.

[0021] Fig.13 is a flowchart of a process according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0022] Although the present invention may take many different forms, for the purpose of promoting an understanding of the principles of the present invention, reference will now be made to the embodiments shown in the accompanying drawings and specific language will be used to describe the embodiments. However, it should be understood that no limitation of the scope of the present invention is intended thereby. Those skilled in the art to which the present invention relates will generally contemplate that any modifications and other modifications to the embodiments and any other applications of the principles of the present invention described herein are covered.

[0023] refer to Figures 1 to 11, discloses a cam phaser 90 for advancing and retarding the exhaust valve 24 of the internal combustion engine 12. The cam phaser 90 includes a rotor 140, the rotor including a hub 142 and a plurality of vanes 144. The plurality of vanes 144 extend radially outward from the hub 142. The cam phaser 90 also includes a stator 170, the stator including an edge 176 and a plurality of lobes 174. The plurality of lobes 174 extend radially inward from the edge 177. The rotor 140 is positioned in the stator 170 so that each vane 144 of the plurality of vanes 144 is positioned between a corresponding pair of lobes 174 of the plurality of lobes 174. Each vane 144 of the rotor 140 has a fully retarded position 192 adjacent to a first lobe 174 of the corresponding pair of lobes 174 to fully retard the exhaust valve 24. Each vane 144 of the rotor 140 has a fully advanced position 194 adjacent to a second lobe 174 of the corresponding pair of lobes 174 to fully advance the exhaust valve 24. The vanes 144 of the rotor 140 rotate 45 degrees from the fully retarded position 192 to the fully advanced position 194 .

[0024] Further references Fig.12 , a method for braking an internal combustion engine 12 includes receiving a charge flow into cylinders 14 of the internal combustion engine 12 to generate exhaust gas by combusting fuel provided to at least a portion of the plurality of cylinders 14. In response to an engine braking request, the method includes changing a phase angle of a camshaft 92, 192 that controls an exhaust valve 24 opening / closing timing and an intake valve 22 opening / closing timing of one or more of the plurality of cylinders 14 to increase a braking power of the engine 12.

[0025] Further references Fig.13 , a method for thermally managing an internal combustion engine 12 or an aftertreatment device 52 includes generating exhaust gas by combusting fuel in at least a portion of a plurality of cylinders of the internal combustion engine 12. In response to a thermal management condition of the engine 12 or the aftertreatment device 52, the method includes changing a phase angle of an exhaust camshaft 92 that controls an opening / closing timing of an exhaust valve 24 by more than 80 crank angle degrees.

[0026] refer to Figure 1 and Figure 2 , a system 10 including a four-stroke internal combustion engine 12 is disclosed. Figure 1 An embodiment is shown in which the engine 12 is a diesel engine, but any engine type is contemplated, including compression ignition, spark ignition, hydrogen, gasoline, natural gas, and combinations thereof. The engine 12 may include a plurality of cylinders 14, which are coupled to cam phasers 90, 190 ( Figure 2 ) is operably connected, and the cam phaser adjusts the intake valve and / or exhaust valve opening and closing timing in response to the cam phaser position command.

[0027] Figure 1 A plurality of cylinders 14 are shown in a certain arrangement, including six cylinders 14 in an inline arrangement for illustration purposes only. Any number of cylinders and any arrangement of cylinders suitable for an internal combustion engine may be utilized. The number of cylinders 14 that may be used may range from one cylinder to eighteen or more cylinders. In addition, the following description will sometimes be made with reference to one of the cylinders 14. It should be appreciated that all or a subset of the other cylinders 14 of the engine 12 may be present in the referenced Figure 2 and corresponding features of cylinder 14 described elsewhere herein.

[0028] like Figure 2 As shown in , cylinder 14 houses piston 16, which is operably attached to crankshaft 18, which is rotated by reciprocating movement of piston 16 in combustion chamber 28 of cylinder 14. Within cylinder head 20 of cylinder 14, there is at least one intake valve 22, at least one exhaust valve 24, and fuel injector 26, which provides fuel to combustion chamber 28 formed by cylinder 14 between piston 16 and cylinder head 20. In other embodiments, fuel may be provided to combustion chamber 28 upstream of combustion chamber 28 by port injection or by injection in the intake system.

[0029] The term "four-stroke" herein means that the piston 16 completes the following four strokes - intake, compression, power and exhaust - during two independent rotations of the engine crankshaft 18. The stroke starts at the top dead center (TDC) position, when the piston 16 is at the top of the cylinder head 20 of the cylinder 14; or starts at the bottom dead center (BDC) position, when the piston 16 has reached its lowest point in the cylinder 14.

[0030] During the intake stroke, piston 16 descends to the bottom of cylinder 14 (not shown) away from cylinder head 20, thereby reducing the pressure in combustion chamber 28 of cylinder 14. Air is drawn in through intake valve 22 when intake valve 22 opens to create a combustion charge in combustion chamber 28.

[0031] In one embodiment, the fuel from the fuel injectors 26 is supplied by a high pressure common rail system 30 ( Figure 1 ) is supplied. A fuel pump (not shown) draws fuel from a fuel tank 32 and feeds it to the common rail fuel system 30. The fuel supplied from the fuel pump is accumulated in the common rail fuel system 30, and the accumulated fuel is supplied to the fuel injectors 26 of each cylinder 14 through a fuel line 34. The accumulated fuel in the common rail system may be pressurized to increase and control the fuel pressure of the fuel delivered to the combustion chamber 28 of each cylinder 14. Other embodiments may contemplate any other type of fuel system for liquid and / or gaseous fuels.

[0032] During the compression stroke, in certain operating modes, both the intake valve 22 and the exhaust valve 24 are closed. The piston 16 returns toward TDC and fuel is injected in the compressed air near TDC in a main injection event, and after a short delay the compressed fuel-air mixture is ignited in the combustion chamber 28. In the case where the engine 12 is a diesel engine, this causes the combustion charge to be ignited. The ignition of the air and fuel causes a rapid increase in pressure in the combustion chamber 28, which is applied to the piston during the power stroke of the piston 16 toward BDC. The combustion phasing in the combustion chamber 28 is calibrated so that the increase in pressure in the combustion chamber 28 pushes the piston 16, thereby providing a net positive value of force / work / power of the piston 16.

[0033] During the exhaust stroke, the piston 16 returns toward TDC while the exhaust valve 24 opens. This action expels the combustion products of the combustion of the fuel in the combustion chamber 28 and drives the spent fuel-air mixture (exhaust) out through the exhaust valve 24. As discussed further below, the cam phaser 90 can be adjusted to change the crank angle at which the exhaust valve 24 opens and closes to change the heat output from the engine 12 into the exhaust system. In addition, the cam phasers 90, 190 can be adjusted to change the crank angle at which both the intake valve 22 and the exhaust valve 24 open and close to increase the braking power of the engine 12 at least during certain operating conditions.

[0034] Intake air flows through intake passage 36 and intake manifold 38 before reaching intake valve 22. Intake passage 36 may be connected to compressor 40a of turbocharger 40 and optional intake throttle 42. Intake air may be cleaned by an air cleaner (not shown), compressed by compressor 40a, and then drawn into combustion chamber 28 through intake throttle 42. Intake throttle 42 may be controlled to affect air flow into cylinder 14.

[0035] Intake passage 36 may be further provided with a cooler 44 disposed downstream of compressor 40a. In one example, cooler 44 may be a charge air cooler (CAC). In this example, compressor 40a may increase the temperature and pressure of the intake air, while CAC 44 may increase the charge density and provide more air to the cylinder. In another example, cooler 44 may be a low temperature aftercooler (LTA). CAC 44 uses air as a cooling medium, while LTA uses a coolant as a cooling medium.

[0036] Exhaust flows out of the combustion chamber 28 and flows into the exhaust passage 46 from the exhaust manifold 48 connecting the cylinder 14 to the exhaust passage 46. The exhaust passage 46 is connected to the turbine 40b and the wastegate 50 of the turbocharger 40 and then leads to the aftertreatment system 52. The exhaust gas discharged from the combustion chamber 28 drives the turbine 40b to rotate. The wastegate 50 is a device that enables a portion of the exhaust gas to bypass the turbine 40b through the passage 54. As a result, less exhaust energy can be used for the turbine 40b, resulting in less power being delivered to the compressor 40a. Generally, this results in a reduced intake pressure rise and lower intake density / flow at both ends of the compressor 40a.

[0037] The wastegate 50 may include an electrically controlled valve 56, which may be an open / closed (two-position) type valve, or a full authority valve that allows control of bypass flow, or anything in between. In some embodiments, the exhaust passage 46 may further or alternatively include an exhaust throttle 58 to adjust the exhaust flow through the exhaust passage 46. The exhaust gas then enters the aftertreatment system 52, which may be a combination of bypass flow and turbine flow.

[0038] The aftertreatment system 52 may include one or more devices for treating and / or removing substances that may be harmful components in the exhaust gas (including carbon monoxide, nitrogen monoxide, nitrogen dioxide, hydrocarbons and / or soot in the exhaust gas). In some examples, the aftertreatment system 52 may include at least one of a catalytic device and a particulate matter filter. The catalytic device may be a diesel oxidation catalyst (DOC) device, an ammonia oxidation (AMOX) catalyst device, a selective catalytic reduction (SCR) device, a three-way catalyst (TWC), a lean NOx trap (LNT), etc. The reduction catalyst may include any suitable reduction catalyst, such as a urea selective reduction catalyst. The particulate matter filter may be a diesel particulate filter (DPF), a split particulate filter (PFF), etc. The function of the PFF is to capture particulate matter in a portion of the flow; in contrast, the entire exhaust volume passes through the particulate filter.

[0039] The arrangement of the components in the aftertreatment system 52 can be any arrangement suitable for use with the engine 12. For example, in one embodiment, the DOC and DPF are arranged upstream of the SCR device. In one example, a reductant delivery device is arranged between the DPF and the SCR device for injecting the reductant into the exhaust gas upstream of the SCR device. The reductant can be urea, diesel exhaust fluid, or any suitable reductant injected in liquid and / or gaseous form.

[0040] A controller 80 is provided to receive data from various sensors as input and to send command signals as output to various actuators. Some of the various sensors and actuators that may be employed are described in detail below. The controller 80 may include, for example, a processor, a memory, a clock, and an input / output (I / O) interface.

[0041] The system 10 may include various sensors (such as an intake manifold pressure / temperature sensor 70, an exhaust manifold pressure / temperature sensor 72, one or more aftertreatment sensors 74 (such as differential pressure sensors, temperature sensors, pressure sensors, composition sensors), engine sensors 76 (which may detect the air / fuel ratio of the air / fuel mixture supplied to the combustion chamber, crank angle, speed of the crankshaft, engine load, etc.) and a fuel sensor 78 that detects fuel pressure and / or other properties of the fuel), a common rail 38, and / or a fuel injector 26. Any other sensors known in the art for use in an engine system are also contemplated, and one or more of the sensors may be physical sensors or virtual sensors.

[0042] The system 10 may also include various actuators for opening and closing the intake valve 22, for opening and closing the exhaust valve 24, for injecting fuel from the fuel injector 26, for opening and closing the wastegate valve 56, for the intake throttle 42, and / or for the exhaust throttle 58. The actuators are not shown in FIG. Figure 1 , but those skilled in the art will know how to implement the mechanisms required for each of the components to perform the intended functions. In addition, in one embodiment, the actuators for opening and closing the intake valve 22 and the exhaust valve 24 are operably connected to the corresponding intake cam phaser 190 or exhaust cam phaser 90, such as Figure 3 shown.

[0043] Further references Figure 3 , further details regarding one embodiment of the exhaust cam phaser 90 or the intake cam phaser 190 are shown. The exhaust cam phaser 90 may adjust the relative positioning and timing of exhaust valve opening and closing during a thermal management operating mode to, for example, provide exhaust gas temperature to thermally manage one or more components of the aftertreatment system 52. The exhaust cam phaser 90 may also adjust the relative positioning and timing of exhaust valve opening and closing in conjunction with the intake cam phaser 190 adjusting intake valve opening and closing during an engine braking operating mode, for example, to increase engine braking power of the engine 12.

[0044] like Figure 3As depicted, the cam phaser 90, 190 is shown with a camshaft 92, 192 including exhaust / intake camshaft lobes 94, 194 and camshaft bearings 96, 196. The exhaust camshaft lobe 94 and the intake camshaft lobe 194 are followed by rocker levers or other motion-transmitting structures (not shown) that actuate the exhaust valve 24 and the intake valve 22, respectively. In one embodiment, the intake camshaft lobe is not phased and is synchronized with the conventional camshaft drive mechanism of the engine. The exhaust cam phaser 90 can be used to control the phase angle of the exhaust camshaft lobe 94 independently of the intake camshaft lobe 194. Likewise, the intake cam phaser 190 can be used to control the phase angle of the intake camshaft lobe 194 independently of the exhaust camshaft lobe 194.

[0045] The cam phasers 90, 190 may each include a front camshaft bearing 98 and an actuator 102 configured to adjust the phase angle of the exhaust camshaft lobe 94 or the intake camshaft lobe 194. A concentric camshaft drive gear 100 is connected to the engine crankshaft 18 ( Figure 2 ) and driven at a specified constant drive ratio. The concentric camshaft drive gear 100 also serves as a housing or mounting seat for the rotor and stator assembly 110 of the exhaust camshaft phaser 90 or the rotor and stator assembly 210 of the intake camshaft phaser 190.

[0046] During the thermal management operating mode, the actuator 102 is configured to control the exhaust cam phaser 90 to selectively advance the phase angle of the exhaust camshaft lobe 94, thereby changing the timing of the exhaust camshaft lobe 94 to provide earlier opening and closing of the exhaust valve 24 as needed during the exhaust stroke of the piston 16. In another embodiment, during the engine braking operating mode, the actuator of the intake cam phaser 190, in conjunction with the exhaust cam phaser 90, is configured to selectively change the phase angles of the intake camshaft lobe 194 and the exhaust camshaft lobe 94 to change the timing of the intake camshaft lobe 194 and the exhaust camshaft lobe 94 to open and close the intake valve 22 and the exhaust valve 24 as needed during the intake stroke and the exhaust stroke of the piston 16, thereby increasing the engine braking power.

[0047] refer to Figures 4 to 5, shows an embodiment of the exhaust cam phaser 90 without the camshaft 92. The exhaust cam phaser 90 includes a drive gear 100 and a rotor and stator assembly 110 mounted to the drive gear 100. The drive gear 100 includes a disc-shaped body 112, wherein the body 112 has a plurality of gear teeth 114 around its periphery. The body 112 includes a central hole 116 for receiving the camshaft 92, and a plurality of fastener cavities 118 for receiving fasteners 120, which are used to mount the rotor and stator assembly 110 to the drive gear 100. The body 112 also includes a locking pin receptacle 122 for movably receiving a locking pin, which can controllably lock and unlock the rotor and stator assembly 110 to the drive gear 100.

[0048] The rotor and stator assembly 110 includes a retainer plate 124, a bias spring 126, a cover plate 128, a coupling 130, and a mounting rod 132. The rotor and stator assembly 110 also includes a rotor 140 and a stator 170. When assembled, and as discussed further below, the rotor 140 is positioned in and rotatable relative to the stator 170, with the blades 144 of the rotor 140 located between corresponding pairs of lugs 174 of the stator 170.

[0049] The cover plate 128 is coupled to the drive gear 100 using fasteners 120 that extend through corresponding stator holes in the stator bore 172 and into the fastener bore 118 of the drive gear 100. The rotor 140 is coupled to the camshaft 92 using a coupling 130 and a mounting rod 132 that extends through a hole 136 in the cover plate 128 and into a slot 138 in the retainer plate 124. The ends of the biasing member 126 are connected to the stator 170 by pins 133 extending from the cover plate 128. The biasing member 126 transmits a rotational force that biases the stator 170 and the drive gear 100 to a desired position, such as a fully retarded position. In the illustrated embodiment, the biasing member 126 is a helically wound torsion spring, but other types of biasing members are also contemplated and are not excluded.

[0050] Figure 6 1 is an elevation view of an embodiment of a rotor and stator assembly 110 , the view looking toward the side of the rotor stator assembly 110 mounted to the drive gear 100 . Figure 7 is along Figure 6 FIG. 1 is an elevation view of the rotor and stator assembly 110 looking toward the drive gear 100 in the opposite direction of FIG. 1. The rotor 140 includes a central hub 142 and a plurality of blades 144 extending radially outward from the central hub 142. The blades 144 are equiangularly spaced from each other around the central hub 142. However, one of the blades 144 has a larger width to accommodate the locking pin 145 and bear most of the load during phasing.

[0051] The center hub 142 includes a center passage 146 extending axially therethrough. The passage 146 is centrally located and extends along the axis of rotation of the rotor and stator assembly 110. A side of the center hub 142 facing the drive gear 100 forms a recess 147 for receiving the camshaft 92. The center hub 144 also includes a hole 148 for receiving the mounting rod 132 that couples the retainer plate 124 to the rotor 140.

[0052] Each of the blades 144 includes a width between opposing sidewalls 152 that tapers such that an outer end 150 of each blade 144 is wider than the width at the hub 142. The opposing sidewalls 152 extend from the hub 142 to the outer end 150 of the corresponding blade 142. Each outer end 150 includes a receptacle 154 that receives a corresponding one of the blade seals 160 therein.

[0053] The rotor 140 is positioned in the stator 170 with the blades 144 positioned between the lugs 174 such that a control volume 178 is defined between each blade 144 and a pair of adjacent lugs 174 located on opposite sides of the corresponding blade 144. The stator 170 includes a rim 176, and each lug 174 includes opposing sidewalls 184 extending from the rim 176 to its corresponding inner end 180. The lugs 174 extend radially inward from the rim 176 toward the hub 142 of the rotor 140. Each of the lugs 174 includes a width between the opposing sidewalls 184 that tapers such that the inner end 180 of each lug 144 is narrower than the width at the rim 176. The inner end 180 of each lug 174 includes a receptacle 182 that receives a corresponding one of the stator seals 190 therein.

[0054] The vanes 144 and the lobes 174 are configured so as to provide a range of motion R for the camshaft 92 and its associated exhaust camshaft lobe 94. In one embodiment, the range of motion R is 45 degrees, thereby allowing the exhaust camshaft lobe 94 to advance or retard the crankshaft 18 by up to 90 degrees of crank angle. In the illustrated embodiment, the width of each vane 144 between the opposing sidewalls 152 and the width 184 of each lobe 174 between the sidewalls 184 are configured to provide a control volume 178 that is sized to allow the rotor 140 to rotate relative to the stator 170 by up to 45 degrees.

[0055] In the illustrated embodiment, there are four lobes 144 on the rotor 140 and four lugs 174 on the stator 170. Other embodiments contemplate three or fewer lobes and lugs, or more than four lobes and lugs, so long as cam phasing is capable of up to 90 degrees of crank angle.

[0056] In one embodiment, the rotor 140 is locked in the starting position, i.e., the fully retarded position 192, as shown in FIG. Figure 7 1, wherein the rotor 140 is rotated clockwise such that the sidewall 152 of each vane 144 is positioned adjacent to or against the sidewall 184 of the corresponding lug 174. The rotor 140 may be rotated counterclockwise toward a fully advanced position, as indicated at 194, wherein control fluid is supplied to and removed from the control volume 178 on opposite sides of each vane 144. The rotation of the rotor 140 may also be stopped at any rotational position between the fully advanced position and the fully retarded position to provide the desired cam phasing.

[0057] The ability of the rotor 140 to rotate relative to the stator 170 to provide up to 90 degrees of crank angle phasing of the exhaust camshaft lobe 194 provides a cost-effective thermal management device, such as maintaining a desired operating efficiency of the aftertreatment system 52 during cold start, idle, warm-up, and / or maneuvering conditions of the engine 12. For example, by advancing the exhaust valve opening timing by up to 90 degrees of crank angle using the cam phaser 90 with the rotor and stator assembly 110, the turbine outlet temperature of the turbine 40b can be maintained at or near a desired threshold temperature during cold start, idle, and / or maneuvering conditions.

[0058] In certain embodiments, the 90 degree authority range provided by the rotor and stator assembly 110 of the cam phaser 90 can be utilized to work the engine 12 harder and increase the pumping work of the engine 12 to maintain a desired threshold temperature of about 300 degrees Celsius at the turbine outlet. In certain embodiments, the use of the rotor and stator assembly 110 of the cam phaser 90 allows exhaust gas recirculation and / or variable geometry turbine (VGT) control to increase aftertreatment temperatures during cold starts and can eliminate or reduce other conditions. In certain embodiments, in a system employing the cam phaser 90 with the rotor and stator assembly 110, an EGR system and / or VGT can be eliminated.

[0059] In certain embodiments, exhaust flow is reduced during maneuvering or idle conditions of the engine 12 to keep the aftertreatment system 52 warm by utilizing the 90 degree range of authority provided by the rotor and stator assembly 110 of the cam phaser 90. For example, exhaust flow at idle may be reduced to cause the engine 12 to work harder at idle and increase exhaust temperature, or air flow through the cylinders 14 may be reduced during maneuvering to reduce cooling of the aftertreatment system 52. As a result, the cam phaser 90 with the rotor and stator assembly 110 may eliminate the use of intake throttle / exhaust throttle control during idle and maneuvering conditions, but its use is not precluded in all embodiments.

[0060] In one embodiment, the wastegate 50 is used in conjunction with the rotor and stator assembly 110 of the cam phaser 90 during certain operating conditions. For example, the wastegate 50 and the rotor and stator assembly 110 of the cam phaser 90 may be controlled to maintain engine-out NOx within specified limits. Using the wastegate 50 in conjunction with the cam phaser 90 with the rotor and stator assembly 110 may reduce disadvantages typically associated with using a cam phaser, such as higher intake manifold temperatures, noise, valve loads, and reduced fuel economy, such as may occur when engine load exceeds 20% of rated or maximum load.

[0061] Figure 8 An embodiment of a rotor seal 160 and / or a stator seal 190 is shown. The seals 160, 190 may include the same configuration as shown, but other configurations are possible as long as the seals 160, 190 are configured to be received in the corresponding receptacles 154, 182 and provide a sealing engagement between the ends of the blades 144 and the rim 176 and / or between the ends of the lugs 174 and the hub 142.

[0062] Each seal 160, 190 includes an elongated body 192 having an outer side 194 facing outwardly from the seal receptacle 154, 182. The elongated body 192 also has an inner side 196 facing inwardly toward the seal receptacle 154, 182. The inner side 196 has a cavity 198 located between opposite end flanges 200, 202 of the elongated body 192. A spring 204 is located in the cavity 198. The spring 204 contacts a corresponding blade 144 or lug 174 in the receptacle 154, 182. The spring 204 biases the outer side 194 of the elongated body 192 outwardly into sealing contact with the adjacent rim 176 or hub 142.

[0063] In one embodiment, the spring 204 is a coil spring. In one embodiment, the spring 204 is a leaf spring. Other embodiments may contemplate other types, configurations, and / or shapes of the spring 204.

[0064] In one embodiment, one or more of the seals 160, 190 are constructed of a plastic material. In one embodiment, one or more of the seals 160, 190 are constructed of a powdered metal material. Other embodiments contemplate other materials for one or more of the seals 160, 190, including metallic materials, elastomers, composite materials, and combinations of these materials.

[0065] Fig. 92 is a perspective view of another embodiment of a rotor and stator assembly 210. In one embodiment, the rotor and stator assembly 210 is disposed on a cam phaser 190 connected to an intake camshaft 192 having a cam lobe 194 that controls the opening and closing timing of the intake valve 22. In the illustrated embodiment, the rotor and stator assembly 210 includes a rotor 212 having a plurality of vanes 214 extending from a central hub 216. The rotor and stator assembly 210 also includes a stator 220 including a plurality of lugs 222 extending radially inward from a rim 224. The rotor 212 is positioned within the stator 220 such that each vane 214 is located within a control volume between a pair of adjacent lugs 222.

[0066] A control fluid, such as oil, is supplied to and exhausted from the control volume 218 to rotate the rotor 212 relative to the stator 220 along a range of motion 226, thereby retarding or advancing the opening and closing timing of the intake valve 22. In one embodiment, the range of motion 226 is 25 degrees, thereby allowing the opening and closing timing of the intake valve 22 to be advanced or retarded within a range of 50 degrees of crank angle.

[0067] In one embodiment, the rotor and stator assembly 210 is applied to the intake cam phaser 190 for adjusting the intake valve opening and closing timing within a range of 50 crank angle degrees, while the rotor and stator assembly 110 is applied to the exhaust cam phaser 90 for adjusting the exhaust valve opening and closing timing within a range of 90 crank angle degrees. The intake valve opening / closing timing can be retarded and combined with the exhaust valve opening / closing timing to increase the braking power of the engine 12 during certain engine operating conditions.

[0068] In one embodiment, a specific engine operating condition for retarding intake valve opening and closing timing and advancing exhaust valve opening and closing timing to increase engine braking power output is an engine speed between 1000 RPM and 2500 RPM. In one embodiment, when between 1000 RPM and 2500 RPM, exhaust cam phaser 90 rotates to advance and / or retard exhaust valve opening / closing timing by up to 20 degrees, and / or intake cam phaser 190 rotates to advance and / or retard intake valve opening / closing timing by up to 25 degrees.

[0069] Fig.10An example of a portion of a flow circuit 300 for providing control fluid to the control volume 178, 218 is provided. A peripheral flow path 302 is formed around the camshaft 92, 192 and radially inwardly extending passages 304. The radially inwardly extending passages 304 provide control fluid to an annular space 306 between the camshaft 92, 192 and the hub 142, 216 of the corresponding rotor 140, 210. A second set of similarly arranged radially inwardly extending passages in the camshaft 92, 192 can also provide control fluid to a set of axially extending passages 308 along the camshaft 92, 192.

[0070] Further references Fig.11 , the rotors 140, 210 include a retard passage 320 and an advance passage 322 in the hub 142, 216. The retard passage 320 provides control fluid to the corresponding control volume 178, 218 to retard the corresponding exhaust valve 24 or intake valve 22, while the corresponding advance passage 322 simultaneously exhausts the control fluid from the control volume 178, 218. Conversely, the advance passage 322 provides control fluid to the corresponding control volume 178, 218 to advance the corresponding exhaust valve 24 or intake valve 22, while the corresponding retard passage 320 simultaneously exhausts the control fluid from the control volume 178, 218.

[0071] It should be understood that the cam phasers 90, 190 may be operated simultaneously to advance the exhaust valve opening / closing timing while retarding the intake valve opening / closing timing. Fig.11 As shown, exhaust cam phaser 90 is parked and rotor 140 is in a fully retarded position, and intake cam phaser 210 is parked and rotor 210 is in a fully advanced position. During an engine braking event, exhaust cam phaser 90 may be operated to advance rotor 140 to an intermediate stop position, such as up to 20 crank angle degrees, while retarding rotor 210 to an intermediate stop position, such as up to 25 crank angle degrees.

[0072] refer to Fig.12 , a flow chart of one embodiment of a routine 1200 for engine braking of engine 12 is provided. Routine 1200 includes operation 1202, which includes operating internal combustion engine 12. In one embodiment, engine 12 includes a plurality of cylinders 14 that receive charge flow from intake passage 36. In addition, at least a portion of the plurality of cylinders 14 receive fuel from fuel system 30 in response to a vehicle or engine speed request.

[0073] Routine 1200 continues at conditional 1204 to determine if an engine braking request is present. The determination that an engine braking request is present may come from, for example, input from a vehicle operator, such as a brake pedal position, an accelerator pedal position, or an engine braking request input switch. If conditional 1204 is negative, routine 1200 returns to operation 1202.

[0074] In response to condition 1204 determining that an engine braking request exists, routine 1200 can continue at operation 1206 to change the phase angle of the camshafts 92, 192, which control the exhaust valve 24 opening / closing timing and the intake valve 22 opening / closing timing of one or more of the multiple cylinders 14 to increase the braking power of the engine 12.

[0075] In one embodiment of routine 1200, changing the phase angle includes operating an exhaust cam phaser 90 coupled to an exhaust camshaft 92 having one or more exhaust cam lobes 94 to advance and / or retard exhaust valve opening / closing timing; and operating an intake cam phaser 100 coupled to an intake camshaft 192 having one or more intake cam lobes 194 to advance and / or retard intake valve 22 opening / closing timing. In one embodiment, the exhaust cam phaser 90 is parked in one of a fully advanced or fully retarded condition, and the intake cam phaser 190 is parked in one of a fully advanced or fully retarded condition.

[0076] In one embodiment, changing the phase angle includes changing the phase angle in response to an engine braking request when the engine speed is between 1000RPM and 2500RPM. In one embodiment, changing the phase angle includes changing the phase angle in response to an engine braking request only when the engine speed is between 1000RPM and 2500RPM.

[0077] In one embodiment, changing the phase angle includes rotating an exhaust cam phaser 90 coupled to an exhaust camshaft 92 having one or more exhaust cam lobes 94 to advance and / or retard the exhaust valve opening / closing timing by up to 20 degrees. In one embodiment, changing the phase angle includes rotating an intake cam phaser 190 coupled to an intake camshaft 192 having one or more intake cam lobes 194 to advance and / or retard the intake valve 22 opening / closing timing by up to 25 degrees.

[0078] refer to Fig.13, a flow chart of one embodiment of a process 1300 for controlling the cam phaser 90 to thermally manage one or more of the engine 12, the aftertreatment device 52, or other components of the system 10 is provided. The process 1300 includes an operation 1302, which includes operating the internal combustion engine 12. In one embodiment, the engine 12 includes a plurality of cylinders 14 that receive a charge flow from the intake passage 36. In addition, in response to a vehicle or engine speed request, at least a portion of the plurality of cylinders 14 receive fuel from the fuel system 30.

[0079] Routine 1300 continues at condition 1304 to determine if a thermal management condition exists. For example, a determination that a thermal management condition exists may come from, for example, a deviation from a target temperature of an aftertreatment component or turbine outlet, a cold start condition, an idle condition, and / or a maneuvering condition. If condition 1304 is negative, routine 1300 returns to operation 1302.

[0080] In response to condition 1304 determining that a thermal management condition exists, routine 1300 continues at operation 1306 to change the phase angle of the exhaust camshaft 92 that controls the opening / closing timing of the exhaust valve 24 by greater than 80 crank angle degrees. In one embodiment, the exhaust valve opening / closing timing is changed during the exhaust stroke of one or more cylinders of the internal combustion engine.

[0081] In one embodiment, the exhaust valve opening / closing timing is changed by 90 degrees of crank angle. In one embodiment, in response to an engine braking request, the phase angle of the exhaust camshaft 92 and the phase angle of the intake camshaft 192 that control the opening / closing timing of the intake valve 22 of one or more of the plurality of cylinders 14 are changed to increase the braking power of the engine 12.

[0082] In one embodiment, the control routines 1200, 1300 are implemented by the controller 80, such as by a processor of the controller 80 executing program instructions (algorithms) stored in a memory of the controller 80. In certain embodiments, the system 10 also includes a controller 80 that is structured or configured to perform certain operations to control the system 10 to achieve one or more target conditions, such as cam phaser positions. In certain embodiments, the controller 80 forms part of a processing subsystem that includes one or more computing devices having memory, processing, and communication hardware. The controller 80 can be a single device or a distributed device, and the functions of the controller 80 can be performed by hardware and / or by instructions encoded on a computer-readable medium.

[0083] In certain embodiments, controller 80 includes one or more modules that are structured to perform the operation of the controller functionally. The description including modules in this article emphasizes the structural independence of the various aspects of the controller, and shows the operation and responsibility grouping of the controller. Other groupings that perform similar overall operations can be understood within the scope of the present application. Modules can be implemented in hardware and / or software on non-transitory computer-readable storage media, and modules can be distributed on various hardware or other computer components.

[0084] Certain operations described herein include operations to interpret or determine one or more parameters. Interpretation or determination as utilized herein includes receiving a value by any method known in the art, including at least receiving a value from a data link or network communication, receiving an electronic signal (e.g., a voltage, frequency, current, or PWM signal) indicating the value, receiving a software parameter indicating the value, reading the value from a memory location on a non-transitory computer-readable storage medium, receiving the value as a runtime parameter by any means known in the art and / or by receiving a value of the parameter from which the interpretation or determination can be calculated and / or by reference to a default value that is interpreted or determined as the parameter value.

[0085] Various aspects of the present disclosure may be contemplated. For example, in one aspect, a cam phaser for advancing and retarding an exhaust valve of an internal combustion engine is provided. The cam phaser includes a rotor and a stator, the rotor including a hub and a plurality of blades, and the stator including an edge and a plurality of lugs. The plurality of blades extend radially outward from the hub, and the plurality of lugs extend radially inward from the edge. The rotor is positioned in the stator so that each of the plurality of blades is positioned between a corresponding pair of lugs in the plurality of lugs. Each blade of the rotor is positioned adjacent to a first lug in the corresponding pair of lugs to fully retard the exhaust valve, and each blade of the rotor is positioned adjacent to a second lug in the corresponding pair of lugs to fully advance the exhaust valve. The blades of the rotor rotate 45 degrees from a fully retarded position to a fully advanced position.

[0086] In one embodiment, the cam phaser includes a plurality of vane seals between the plurality of vanes of the rotor and the rim of the stator, and a plurality of lug seals between the plurality of lugs of the stator and the hub of the rotor.

[0087] In further embodiments, at least one of the plurality of blade seals and the plurality of flange seals is comprised of a plastic material.

[0088] In further embodiments, at least one of the plurality of vane seals and the plurality of flange seals is comprised of a powdered metal material.

[0089] In other embodiments, each of the plurality of blades includes an outer end facing the rim of the stator, and each of the plurality of blade seals is positioned within a seal receptacle of a corresponding one of the outer ends. Each of the plurality of lugs includes an inner end facing the hub of the rotor, and each of the plurality of lug seals is positioned within a seal receptacle of a corresponding one of the inner ends.

[0090] In yet another embodiment, at least one of the plurality of vane seals and the plurality of lug seals comprises an elongated body having an outer side facing outwardly from a sealing receptacle. The elongated body has an inner side facing inwardly toward the sealing receptacle, the inner side having a cavity located between opposite end flanges of the elongated body. A spring is located in the cavity, the spring contacting a corresponding lug or vane in the receptacle. The spring biases the outer side of the elongated body outwardly into sealing contact with an adjacent rim or hub.

[0091] In one embodiment, the rotor is locked in a starting position adjacent the first lobe to fully retard the exhaust valve.

[0092] In one embodiment, the cam phaser includes a drive gear positioned on a first side of the stator, a cover plate positioned on a second side of the stator opposite the first side, and a plurality of fasteners extending through the stator and engaging the cover plate to the drive gear.

[0093] In further embodiments, the cam phaser includes a biasing member coupled to the cover plate, the biasing member biasing the plurality of lobes of the stator toward corresponding lobes of the plurality of lobes of the rotor.

[0094] In yet another embodiment, the cam phaser includes a camshaft positioned in the hub of the rotor, and a retainer plate connected to the camshaft, the cover plate, and the biasing member.

[0095] Another aspect of the present disclosure includes a method for braking an internal combustion engine. The method includes: receiving a charge flow into a plurality of cylinders of the internal combustion engine to generate exhaust gas by combusting fuel provided to at least a portion of the plurality of cylinders; and in response to an engine braking request, changing a phase angle of a camshaft that controls exhaust valve opening / closing timing and intake valve opening / closing timing of one or more of the plurality of cylinders to increase braking power of the engine.

[0096] In one embodiment, changing the phase angle includes: operating an exhaust cam phaser connected to an exhaust camshaft having one or more exhaust cam lobes to advance and / or retard the opening / closing timing of the exhaust valve; and operating an intake cam phaser connected to an intake camshaft having one or more intake cam lobes to advance and / or retard the opening / closing timing of the intake valve.

[0097] In further implementations, the method includes parking the exhaust cam phaser in one of a fully advanced condition or a fully retarded condition and parking the intake cam phaser in one of a fully advanced condition or a fully retarded condition.

[0098] In one embodiment, changing the phase angle includes changing the phase angle in response to the engine braking request when the engine speed is between 1000 RPM and 2500 RPM.

[0099] In further embodiments, varying the phase angle includes rotating an exhaust cam phaser coupled to an exhaust camshaft having one or more exhaust cam lobes to advance and / or retard the exhaust valve opening / closing timing by up to 20 degrees.

[0100] In further embodiments, varying the phase angle includes rotating an intake cam phaser coupled to an intake camshaft having one or more intake cam lobes to advance and / or retard the intake valve opening / closing timing by up to 25 degrees.

[0101] Another aspect relates to a method for thermal management of an aftertreatment device or an internal combustion engine. The method includes generating exhaust gas by combusting fuel received in at least a portion of a plurality of cylinders of the internal combustion engine; and changing a phase angle of an exhaust camshaft that controls exhaust valve opening / closing timing by more than 80 crank angle degrees in response to a thermal management condition of the engine or the aftertreatment device.

[0102] In one embodiment, the exhaust valve opening / closing timing is varied during the exhaust stroke of one or more cylinders of the internal combustion engine.

[0103] In one embodiment, the exhaust valve opening / closing timing is changed by 90 crank angle degrees.

[0104] In one embodiment, the method includes changing the phase angle of the exhaust camshaft and changing the phase angle of the intake camshaft that controls the opening / closing timing of intake valves of one or more of the plurality of cylinders to increase braking power of the engine in response to engine braking conditions.

[0105] Although the present invention has been illustrated and described in detail in the accompanying drawings and in the foregoing description, these should be regarded as illustrative rather than restrictive in nature, and it should be understood that only certain exemplary embodiments have been shown and described. It will be appreciated by those skilled in the art that many modifications may be made in the exemplary embodiments without departing substantially from the present invention. Therefore, all such modifications are intended to be included within the scope of the present disclosure as defined by the appended claims.

[0106] When reading the claims, it is intended that when words such as "a," "an," "at least one," or "at least one portion" are used, it is not intended to limit the claim to only one item unless the claim explicitly states otherwise. When the language "at least a portion" and / or "a portion" is used, the item may include a portion and / or the entire item unless explicitly stated otherwise.

Claims

1. A cam phaser for advancing and retarding an exhaust valve of an internal combustion engine, the cam phaser comprising: a rotor comprising a hub and a plurality of blades extending radially outward from the hub; A stator comprising a rim and a plurality of lugs extending radially inwardly from the rim, wherein: the rotor being positioned in the stator such that each of the plurality of blades is positioned between a corresponding pair of lugs of the plurality of lugs; each lobe of the rotor is positioned adjacent a first lobe of the corresponding pair of lobes to fully retard the exhaust valve; Each lobe of the rotor is positioned adjacent a second lobe of the corresponding pair of lobe to fully advance the exhaust valve; and The vanes of the rotor rotate 45 degrees from a fully retarded position to a fully advanced position.

2. The cam phaser of claim 1 further comprising: a plurality of vane seals between the plurality of vanes of the rotor and the rim of the stator; A plurality of lug seals between the plurality of lugs of the stator and the hub of the rotor. 3 . The cam phaser of claim 2 , wherein at least one of the plurality of vane seals and the plurality of flange seals is comprised of a plastic material. 4 . The cam phaser of claim 2 , wherein at least one of said plurality of vane seals and said plurality of flange seals is comprised of a powdered metal material.

5. The cam phaser of claim 2, wherein: Each of the plurality of vanes includes an outer end facing the rim of the stator, and each of the plurality of vane seals is positioned within a seal receptacle of a corresponding one of the outer ends; and Each of the plurality of lugs includes an inner end facing the hub of the rotor, and each of the plurality of lug seals is positioned within a seal receptacle of a corresponding one of the inner ends.

6. The cam phaser of claim 5, wherein at least one of said plurality of vane seals and said plurality of lug seals comprises: an elongated body having an outer side facing outwardly from the sealing receptacle, the elongated body having an inner side facing inwardly toward the sealing receptacle, the inner side having a cavity located between opposite end flanges of the elongated body; as well as A spring is positioned in the cavity, the spring contacting a corresponding lug or blade in the socket, the spring biasing the outer side of the elongated body outwardly into sealing contact with an adjacent rim or hub. 7 . The cam phaser of claim 1 , wherein said rotor is locked in a starting position adjacent said first lobe to fully retard said exhaust valve.

8. The cam phaser of claim 1 further comprising: a drive gear positioned on a first side of the stator; a cover plate positioned on a second side of the stator opposite the first side; as well as A plurality of fasteners extend through the stator and couple the cover plate to the drive gear.

9. The cam phaser of claim 8 further comprising: A biasing member is coupled to the cover plate, wherein the biasing member biases the plurality of lugs of the stator toward corresponding ones of the plurality of blades of the rotor.

10. The cam phaser of claim 9 further comprising: a camshaft located in the hub of the rotor; as well as A retainer plate is connected to the camshaft, the cover plate, and the biasing member.

11. A method for braking an internal combustion engine, the method comprising: receiving a charge flow into a plurality of cylinders of the internal combustion engine to produce exhaust gas by combusting fuel provided to at least a portion of the plurality of cylinders; as well as In response to an engine braking request, a phase angle of a camshaft that controls exhaust valve opening / closing timing and intake valve opening / closing timing of one or more of the plurality of cylinders is changed to increase braking power of the engine.

12. The method of claim 11, wherein changing the phase angle comprises: operating an exhaust cam phaser coupled to an exhaust camshaft having one or more exhaust cam lobes to advance and / or retard the exhaust valve opening / closing timing; as well as An intake cam phaser coupled to an intake camshaft having one or more intake cam lobes is operative to advance and / or retard the intake valve opening / closing timing.

13. The method according to claim 12, further comprising: parking the exhaust cam phaser in one of a fully advanced condition or a fully retarded condition; as well as The intake cam phaser is parked in one of a fully advanced condition or a fully retarded condition.

14. The method of claim 11, wherein changing the phase angle comprises changing the phase angle in response to the engine braking request when engine speed is between 1000 RPM and 2500 RPM.

15. The method of claim 14, wherein varying the phase angle comprises rotating an exhaust cam phaser coupled to an exhaust camshaft having one or more exhaust cam lobes to advance and / or retard the exhaust valve opening / closing timing by up to 20 degrees.

16. The method of claim 14 or claim 15, wherein varying the phase angle comprises rotating an intake cam phaser connected to an intake camshaft having one or more intake cam lobes to advance and / or retard the intake valve opening / closing timing by up to 25 degrees.

17. A method for thermal management of an aftertreatment device or an internal combustion engine, the method comprising: generating exhaust gas by combusting fuel received in at least a portion of a plurality of cylinders of the internal combustion engine; as well as In response to a thermal management condition of the engine or aftertreatment device, a phase angle of an exhaust camshaft that controls exhaust valve opening / closing timing is changed by more than 80 crank angle degrees.

18. The method of claim 17, wherein the exhaust valve opening / closing timing is varied during an exhaust stroke of one or more cylinders of the internal combustion engine.

19. The method of claim 17, wherein the exhaust valve opening / closing timing is changed by 90 crank angle degrees.

20. The method of claim 17, further comprising changing the phase angle of the exhaust camshaft and changing a phase angle of an intake camshaft that controls intake valve opening / closing timing of one or more of the plurality of cylinders to increase braking power of the engine in response to an engine braking condition.

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