Method and system for kinetic energy recovery in a hybrid powertrain during engine off operation

Abstract

Methods and systems for kinetic energy recovery in a hybrid powertrain during engine stop operation. The present disclosure provides a hybrid powertrain system including an engine, an electric motor / generator ("MG"), a clutch coupled to the engine and the MG, a transmission coupled to the MG, an energy storage system connected to the MG, and a controller coupled to the engine, the MG, the clutch, the transmission, and the energy storage system. The controller is configured to initiate engine shutdown, allow engine torque and MG torque to decrease to or near zero, shift the transmission to neutral, operate the MG in generator mode to load the engine to recover kinetic energy from the engine, disengage the clutch to decouple the MG from the engine, increase the speed of the MG to a target speed, and shift the transmission in response to the MG reaching the target speed.

Description

Technical Field

[0001] The disclosed embodiments generally relate to hybrid powertrain control, and more particularly to methods and systems for recovering energy from an internal combustion engine during periods of inactivity to improve the overall efficiency of the hybrid powertrain. Background Technology

[0002] Hybrid vehicles typically consist of an internal combustion engine and at least one electric motor / generator (“MG (motor / generator)”). Many hybrid vehicles use an engine start / stop function, where the vehicle controller stops the internal combustion engine in certain scenarios (e.g., when the vehicle is at zero speed, such as at a parking light) to consume less fuel and reduce emissions. While this engine stop reduces energy consumption in terms of fuel, restarting the engine after it has stopped consumes energy. In some vehicles, a small electric starter is used to restart the engine, but this method is inefficient from an energy consumption point of view, especially when the powertrain includes a large internal combustion engine and stop-start operations occur frequently. Other restart methods involve engaging the clutch while the vehicle is at speeds powered by the MG (similar to a vehicle’s “bumpstarting”), but this method slows the vehicle down, loses energy due to clutch slippage, and affects driving performance.

[0003] Alternatively, the MG (engine starter) of the powertrain can be used to restart the engine. Full hybrid vehicles (also known as “strong” hybrids) have a relatively large MG that can propel the vehicle without using the engine. During engine restart, the transmission can be placed in neutral to disconnect the MG from the final drive, making the MG usable for restarting the engine. The MG can then be reduced to zero speed, and the clutch between the MG and the engine can be engaged, resulting in almost zero energy loss due to clutch slippage. The engine can then be started using the MG. This method also leads to undesirable energy consumption. Therefore, further improvements in the energy efficiency of hybrid vehicles using start / stop technology are clearly needed. Summary of the Invention

[0004] In one embodiment, this disclosure provides a hybrid powertrain system comprising: an engine; at least one electric motor / generator (“MG”); a clutch coupled to the engine and the at least one MG; a transmission coupled to the at least one MG; an energy storage system connected to the at least one MG; and a controller operatively coupled to the engine, the at least one MG, the clutch, the transmission, and the energy storage system. The controller includes a processor and a memory, the memory including instructions that, when executed by the processor, cause the controller to: initiate an engine shutdown, allowing engine torque and torque associated with the at least one MG to decrease to zero or near zero; shift the transmission to neutral; operate the at least one MG in generator mode; thereby loading the engine via the clutch to recover kinetic energy from the engine; disengage the clutch to separate the at least one MG from the engine; increase the speed of the at least one MG to a target speed; and, in response to the at least one MG reaching the target speed, shift the transmission. In one aspect of this disclosure, the instructions executed by the processor further cause the controller to use power from the at least one MG to propel the vehicle after shifting the transmission. In a variant of this aspect, the vehicle is a full hybrid vehicle. In another variation, the engine is an internal combustion engine. In yet another variation of this aspect, initiating engine shutdown includes determining, based on input from at least one sensor, that power from the engine is not required to propel the vehicle. In another variation, the transmission is shifted to neutral to disengage the at least one MG from the vehicle's final drive. In another aspect of this embodiment, instructions executed by the processor also cause the controller to control the at least one MG to store energy recovered from the engine by the at least one MG in an energy storage system. In yet another aspect, the energy storage system includes multiple batteries.

[0005] In another embodiment, this disclosure provides a method for recovering energy from an engine in a hybrid powertrain including at least one electric motor / generator (“MG”), the method comprising the steps of: initiating an engine shutdown; allowing engine torque and torque associated with the at least one MG to decrease to zero or near zero; shifting a transmission coupled to the at least one MG to neutral; operating the at least one MG in generator mode to load the engine via a clutch to recover kinetic energy from the engine; disengaging the clutch to disconnect the at least one MG from the engine; increasing the speed of the at least one MG to a target speed; and shifting the transmission in response to the at least one MG reaching the target speed. One aspect of this embodiment further includes using power from the at least one MG to propel the vehicle after shifting the transmission. In a variant of this aspect, the vehicle is a full hybrid vehicle. In another variant, the engine is an internal combustion engine. In yet another variant, initiating an engine shutdown includes determining, based on input from at least one sensor, that power from the engine is not required to propel the vehicle. In yet another variant, shifting the transmission to neutral disconnects the at least one MG from the vehicle's final drive unit. Another aspect of this embodiment includes storing energy recovered from the engine by the at least one MG in an energy storage system connected to the at least one MG. In this further aspect, the energy storage system includes multiple batteries.

[0006] In another embodiment, this disclosure provides a hybrid powertrain system comprising: an engine; at least one electric motor / generator (“MG”); a first clutch coupled to the engine and the at least one MG; a second clutch coupled between the at least one MG and a final drive unit; an energy storage system connected to the at least one MG; and a controller operatively coupled to the engine, the at least one MG, the first clutch, the second clutch, and the energy storage system, the controller including a processor and a memory, the memory including instructions that, when executed by the processor, cause the controller to: initiate an engine shutdown, allowing engine torque and torque associated with the at least one MG to decrease to zero or near zero; disengage the second clutch, causing the at least one MG to operate in generator mode, thereby loading the engine through the first clutch to recover kinetic energy from the engine; disengage the first clutch to separate the at least one MG from the engine; increase the speed of the at least one MG to a target speed; and, in response to the at least one MG reaching the target speed, disengage the second clutch.

[0007] It should be appreciated that, in various embodiments, the foregoing concepts and the additional concepts discussed below can be set in any suitable combination. Furthermore, other advantages and novel features of this disclosure will become apparent when considered in conjunction with the accompanying drawings, based on the following detailed description of various non-limiting embodiments. Attached Figure Description

[0008] The accompanying drawings are not intended to be drawn to scale. In the drawings, identical or nearly identical components illustrated in different figures can be represented by the same numbers. For clarity, not every component is labeled in every figure. In the figures:

[0009] Figure 1 This is an advanced concept block diagram of the vehicle's hybrid powertrain;

[0010] Figure 2 It is a flowchart depicting the engine shutdown and restart process according to this disclosure;

[0011] Figure 3 It is a pie chart depicting the simulation results of energy recovery and energy loss using the process according to this disclosure;

[0012] Figure 4 It is a high-level concept block diagram of an alternative implementation of the vehicle's hybrid powertrain; and

[0013] Figure 5 This is a flowchart depicting an alternative implementation of the engine shutdown and restart process according to the present disclosure. Detailed Implementation

[0014] Now, referring to Figure 1 A conceptual block diagram of a hybrid vehicle 10 including a powertrain 12 is shown, the powertrain having an internal combustion engine 14, a clutch 16, an electric motor (hereinafter referred to as an electric motor / generator (MG 18)), and a transmission 20. The vehicle 10 also includes an energy storage system 22, a final drive unit 24, and a controller including a processor 28 and a memory 30. The powertrain 12 may include other components and is depicted only as shown to illustrate the operation of the technology disclosed herein. For example, the powertrain 12 may include an additional clutch 16 and / or an additional MG 18. Furthermore, the vehicle 10 can be configured as a mild hybrid, full hybrid, or plug-in hybrid. Additionally, while the description herein contemplates the use of the powertrain 12, the teachings of this disclosure can be used in other applications, such as hydraulic hybrid powertrains. Finally, the teachings of this disclosure can be applied to powertrains of devices other than vehicles.

[0015] The internal combustion engine 14 is mechanically connected to the MG 18 via a clutch 16. The engine 14 can be any type of combustion engine, including but not limited to spark-ignition or compression-ignition engines with any configuration, size and / or fuel type.

[0016] The MG 18 is also mechanically connected to the transmission 20, which is in turn mechanically connected to the final drive unit 24, which includes a differential mechanically connected to a drive shaft 32 that connects two or more wheels 34 together.

[0017] The MG 18 is electrically connected to the energy storage system 22 to receive and deliver power to the energy storage system 22. In some examples, the energy storage system 22 includes, but is not limited to, batteries such as lithium-ion batteries, nickel-metal hydride batteries, or lead-acid batteries. The energy storage system 22 may alternatively include supercapacitors or other types of energy storage devices. Figure 1 In the diagram, thick lines represent mechanical connections, while thin lines represent electrical connections, such as those via wired or wireless means.

[0018] As shown above, the controller 26 includes a processor 28 and a memory storage device 30. The processor 28 can be any suitable processor, such as a central processing unit (CPU), state machine, system-on-a-chip (SoC), etc. The memory storage device 30 can be any suitable memory, such as random access memory (RAM), read-only memory (ROM), flash memory, etc. As shown, the controller 26 is electrically connected to the engine 14, clutch 16, MG 18, transmission 20, and energy storage device 22, enabling the controller 26 to detect any input from these components and send operating signals to control the operation of these components.

[0019] In some examples, the components electrically connected to controller 26 have one or more sensors (not shown) coupled to them, which perform measurements indicating the current state of the component, such as the state of charge (SOC) of energy storage device 22, the temperature of engine 14 and / or its aftertreatment system (not shown), the open / closed state of clutch 16, and so on. In some examples, such data is stored in memory storage device 30 of controller 26, so that controller 26 can use the stored data at any time without having to perform new measurements when needed. In some examples, the data in memory storage device 30 is updated frequently at a constant rate, i.e., new measurements are performed at predetermined intervals, thereby maintaining the "freshness" of the data. In some examples, controller 26 has instructions (e.g., calculation algorithms) stored in memory storage device 30, which processor 28 uses to perform control processing as disclosed herein.

[0020] Controller 26 may form part of a processing subsystem that includes one or more computing devices having a non-transitory computer-readable storage medium, a processor or processing circuitry, and communication hardware. Controller 26 may be a single device or a distributed device, and the functionality of the controller may be executed by hardware and / or by processing instructions stored on a non-transitory machine-readable storage medium. Example processors include: application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), and microprocessors including firmware. Example non-transitory computer-readable storage media include: random access memory (RAM), read-only memory (ROM), flash memory, hard disk storage devices, electrically erasable programmable ROM (EEPROM), electrically programmable ROM (EPROM), magnetic disk storage devices, and any other medium that can be used to carry or store processing instructions and data structures and can be accessed by a general-purpose or special-purpose computer or other processing device.

[0021] Some operations of the controller 26 described herein include operations for interpreting and / or determining one or more parameters. As utilized herein, interpreting or determining includes receiving a value by any method known in the art, including receiving an electronic signal (e.g., voltage, frequency, current, or pulse width modulation signal) indicating the value from a data link, network communication, or input device, such as the SOC of the energy storage system 22; receiving a computer-generated parameter indicating the value; reading the value from a memory location on a non-transitory machine-readable storage medium; receiving the value as a runtime parameter by any means known in the art; and / or by receiving a value from which the parameter can be calculated and interpreted; and / or by referencing a default value interpreted as a parameter value.

[0022] As used herein, the term "logic" includes software and / or firmware executing on one or more programmable processors, application-specific integrated circuits, field-programmable gate arrays, digital signal processors, hardwired logic, or combinations thereof. Therefore, various logics can be implemented in any suitable manner, depending on the implementation, and will remain so according to the implementations disclosed herein.

[0023] The embodiments of the technology described herein can be implemented in any of a number of ways. For example, these embodiments can be implemented using hardware, software, or a combination thereof. When implemented in software, the software code can execute on any suitable processor or set of processors, whether provided in a single computing device or distributed among multiple computing devices. Such processors can be implemented as integrated circuits, with one or more processors residing in an integrated circuit assembly, including commercially available integrated circuit assemblies known in the art, such as CPU chips, GPU chips, microprocessors, microcontrollers, or coprocessors. Alternatively, the processor can be implemented in custom circuitry such as ASICs, or in semi-custom circuitry derived from configuring programmable logic devices. As yet another alternative, the processor can be part of a larger circuit or semiconductor device, whether commercially available, semi-custom, or custom. As a specific example, some commercially available microprocessors have multiple cores, such that one or a subset of these cores can constitute a processor. However, the processor can be implemented using circuitry employing any suitable format.

[0024] Furthermore, the various methods or processes outlined in this paper can be encoded into software that can be executed on one or more processors employing any of a variety of operating systems or platforms. Additionally, such software can be written using any of a variety of suitable programming languages ​​and / or programming or scripting tools, and can also be compiled into executable machine language code or intermediate code that executes on a framework or virtual machine.

[0025] In this regard, the disclosed embodiments can be embodied in a computer-readable storage medium (or multiple computer-readable media) (e.g., computer memory, one or more floppy disks, optical disks (CDs), optical discs, digital video discs (DVDs), magnetic tape, flash memory, circuit configurations in field-programmable gate arrays or other semiconductor devices, or other tangible computer storage media) encoded with one or more programs, which, when executed on one or more computers or other processors, perform methods to implement the various embodiments of the present disclosure discussed herein. As apparent from the foregoing examples, a computer-readable storage medium can retain information for a sufficient time to provide computer-executable instructions in a non-transitory form. One or more such computer-readable storage media can be transportable such that one or more programs stored thereon can be loaded onto one or more different computers or other processors to implement the various aspects of the present disclosure discussed above. As used herein, the term "computer-readable storage medium" covers only non-transitory computer-readable media that can be considered as an article of manufacture (i.e., an article of manufacture) or a machine. Alternatively or additionally, the present disclosure can be embodied in computer-readable media other than computer-readable storage media, such as propagating signals.

[0026] The terms “program” or “software” are used herein in a general sense to refer to any type of computer code or set of computer-executable instructions that can be used to program a computing device or other processor to implement the various aspects of this disclosure as discussed above. Furthermore, it should be appreciated that, according to one aspect of this disclosure, one or more computer programs that perform the methods of this disclosure during execution do not need to reside on a single computer or processor, but can be distributed in a modular manner among multiple different computers or processors to implement the various aspects of this disclosure.

[0027] Computer-executable instructions can take various forms, such as program modules, and can be executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. In various implementations, the functionality of program modules can typically be combined or distributed as needed.

[0028] Furthermore, data structures can be stored in computer-readable media in any suitable form. For simplicity, a data structure can be shown as having fields that are related by their positions within the data structure. Such relationships can also be implemented by assigning the storage of the fields to locations in the computer-readable medium that carry the relationship between the fields. However, any suitable mechanism can be used to establish relationships between the information in the fields of a data structure, including by using pointers, labels, or other mechanisms that establish relationships between data elements.

[0029] Return to Figure 1 In operation, engine 14 can generate power in a known manner, which is transmitted via clutch 16 and MG 18 to drive the operation of transmission 20. Transmission 20 can be shifted into different gears (not shown) to increase or decrease the operating speed of final drive unit 24, and thus increase or decrease the rotational speed of wheels 34 via drive shaft 32. In a known manner, in addition to or instead of engine 14, MG 18 can supply power to transmission 20 to rotate wheels 34 in the manner described above.

[0030] In the depicted embodiment, vehicle 10 includes a start / stop function implemented by controller 26 to control the operation of engine 14. More specifically, when power from engine 14 is not required to propel vehicle 10, such as when vehicle 10 is stopped or coasting downhill due to inertia, controller 26 can shut down engine 14, thereby saving fuel and reducing emissions. Typically, when engine 14 is shut down in this manner, engine 14 coasts to deceleration or zero speed due to friction. When the engine controller or operator instructs that torque from engine 14 is required, such as by pressing the accelerator pedal or releasing the brake pedal, engine 14 is restarted using one of a variety of known restart mechanisms. According to the principles of this disclosure, engine 14 is decelerated using MG 18 during periods of inactivity in order to recover kinetic energy in the following manner.

[0031] Now refer to Figure 2 An exemplary process 40 according to this disclosure is illustrated. In step 42, controller 26 initiates an engine shutdown command, such as when processor 28 determines from various sensors that no power is required from engine 14. As shown above, this can occur in various scenarios, such as when the speed of vehicle 10 is zero or near zero (e.g., at a parking light), or when the torque required by engine 14 is zero or near zero (e.g., when vehicle 10 is coasting downhill). Regardless of the reason for the engine shutdown command, controller 26 sends one or more control signals to engine 14 and / or components associated with engine 14 to terminate engine operation. For example, the fuel injection system (not shown) associated with engine 14 may be stopped from injecting fuel into the engine cylinders.

[0032] When engine 14 is terminated in step 42, it will briefly "coast" to a near-zero torque condition. In step 44 of process 40, when engine 14 and MG 18 are allowed to reduce their respective torque outputs to zero or near zero, controller 26 monitors engine 14 and MG 18 (the MG may also be in motion just before the engine stop command). When both engine 14 and MG 18 are in a zero or near-zero torque condition, controller 26 commands transmission 20 to shift to neutral. This disconnects MG 18 from the final drive unit 24, allowing MG 18 to be used to recover energy from engine 14 (as described below) without directly affecting the speed of vehicle 10. At this point in process 40, engine 14 can still decelerate to zero or near zero speed. In other words, the internal moving components of engine 14 (e.g., pistons, crankshaft, etc.) will continue to move for a period of time and will eventually stop due to friction and other forces if the stop condition is long enough.

[0033] After shifting transmission 20 to neutral (step 46), in step 48, MG 18 is used in generator mode to load engine 14 and recover its kinetic energy. This additional load on engine 14 allows it to reach zero or near-zero speed more quickly than simply allowing it to coast to a stop. The energy recovered from engine 14 by MG 18 is provided to energy storage system 22 and stored for future use.

[0034] In step 50 of process 40, after engine 14 and MG 18 have decelerated to zero speed or near zero speed, controller 26 disengages clutch 16. This disengages engine 14 from MG 18 and allows MG 18 to re-engage transmission 20. Once disengaged from engine 14 at step 50, in step 52, controller 26 commands MG 18 to accelerate back to a target speed, which corresponds to the speed at which transmission 20 shifts back. In step 54, controller 26 causes transmission 20 to shift back. It should be understood that the gear shifted to by transmission 20 in step 54 is not required to be the same as the gear shifted to by transmission 20 in step 46. Thereafter, MG 18 is used to propel vehicle 10 in all-electric mode, as shown in step 56. MG 18 will continue to be used to propel vehicle 10 until additional torque from engine 14 is required to meet the operator's needs. When additional torque is required, controller 26 restarts engine 14 in any of a variety of ways known to those skilled in the art.

[0035] Now refer to Figure 3 Simulation results 60 are presented using the principles outlined above. These results were generated by simulating a powertrain with a diesel engine and an MG capable of absorbing approximately 700 nm of torque from the engine as it decelerates to the zero-speed condition described above. In this example, the engine contains a total of 30.17 kJ of kinetic energy before stopping. As shown, approximately 67% of the engine's kinetic energy was recovered using the methods described herein (see “Recovered Energy” section 62). The simulation indicates that approximately 21% of the engine's initial kinetic energy is lost due to engine pumping and friction (section 64), and approximately 12% of that kinetic energy is lost due to inefficiencies associated with the MG (section 66).

[0036] Now refer to Figure 4 The diagram illustrates a hybrid vehicle 10A with an alternative configuration including a powertrain 12A, comprising an internal combustion engine 14A, a clutch 16A, an MG 18A, and a second clutch 19. In this embodiment, a transmission 20 is optional. As... Figure 1The vehicle 10A further includes an energy storage system 22A, a final drive unit 24A, and a controller 26A, which includes a processor 28A and a memory 30A. The powertrain 12A may include other components and is depicted only as shown in the figures to illustrate the operation of the technology disclosed herein. For example, the powertrain may include an additional MG 18. Furthermore, the vehicle 10A can be configured as a mild hybrid, full hybrid, or plug-in hybrid. Additionally, while the description herein contemplates the use of the powertrain 12A, the teachings of this disclosure can be applied to other applications, such as hydraulic hybrid powertrains. Finally, the teachings of this disclosure can be applied to powertrains of devices other than vehicles.

[0037] Now refer to Figure 5 An exemplary process 40A according to this disclosure is illustrated. In step 42A, controller 26A initiates an engine shutdown command, such as by processor 28A determining from various sensors that no power is required from engine 14A. As shown above, this can occur in various scenarios, such as when the speed of vehicle 10A is zero or near zero (e.g., at a parking light), or when the torque required by engine 14A is zero or near zero (e.g., when vehicle 10A is coasting downhill). Regardless of the reason for the engine shutdown command, controller 26A sends one or more control signals to engine 14A and / or components associated with engine 14A to terminate engine operation. For example, the fuel injection system (not shown) associated with engine 14A may be stopped from injecting fuel into the engine cylinders.

[0038] When engine 14A terminates in step 42A, it will briefly "coast" to a near-zero torque condition. In step 44A of process 40A, controller 26A monitors engine 14A and MG 18A (which may also be in motion just before the engine stop command) as engine 14A and MG 18A are allowed to reduce their respective torque outputs to zero or near zero. When both engine 14A and MG 18A are in a zero or near-zero torque condition, controller 26A disengages the second clutch 19. This disconnects MG 18A from the final drive unit 24A, allowing MG 18A to be used to recover energy from engine 14A (as described below) without directly affecting the speed of vehicle 10A. At this point in process 40A, engine 14A can still decelerate to zero or near zero speed. In other words, the internal moving components of engine 14A (e.g., pistons, crankshafts, etc.) will continue to move for a certain period of time, and if the shutdown condition is long enough, it will eventually stop due to friction and other forces.

[0039] After the second clutch 19 is disengaged (step 46), in step 48A, MG 18A is used in generator mode to load engine 14A and recover the engine's kinetic energy. This additional load on engine 14A allows it to reach zero or near-zero speed more quickly than simply allowing engine 14A to coast to a stop. The energy recovered from engine 14A by MG 18A is provided to energy storage system 22A and stored for future use.

[0040] In step 50A of processing 40A, after engine 14A and MG 18A have decelerated to zero speed or near zero speed, controller 26A disengages clutch 16A. This disengages engine 14A from MG 18A and allows MG 18A to re-engage transmission 20A. Once disengaged from engine 14A at step 50A, in step 52A, controller 26A commands MG 18A to accelerate back to the target speed. In step 54, controller 26A disengages second clutch 19. MG 18A is then used to propel vehicle 10A in all-electric mode, as shown in step 56A. MG 18A will continue to propel vehicle 10A until additional torque from engine 14A is required to meet the operator's needs. When additional torque is required, controller 26A restarts engine 14A in any of a variety of ways known to those skilled in the art.

[0041] As can be clearly seen from the foregoing, the benefits of the method described herein can be partly dependent on the torque capability of the MG 18 for at least two reasons. First, because the larger MG 18 completes step 48 (i.e., brings the engine speed to zero or near zero more quickly), less energy is lost through engine pumping and friction. Second, also as a result of the faster execution of step 48, the larger MG 18 allows for a faster completion of the entire process of stopping the engine and enabling the MG to power the vehicle. This reduces the torque interruption time associated with engine shutdown and results in a smaller impact on vehicle driving performance.

[0042] Furthermore, it should be understood that by reducing energy losses during engine shutdown, this method reduces losses associated with the engine start / stop system. Consequently, controller 26 can initiate engine shutdown more frequently, thereby improving energy efficiency and reducing emissions.

[0043] While various embodiments of this disclosure have been shown and described, it should be understood that these embodiments are not limited thereto. Those skilled in the art can change, modify, and further apply these embodiments. Therefore, these embodiments are not limited to the details previously shown and described, but also include all such changes and modifications.

[0044] Furthermore, the connecting lines shown in the various figures included herein are intended to represent exemplary functional relationships and / or physical connections between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in a real system. However, any benefit, advantage, or solution that arises or becomes more significant may be obtained, and any element may not be considered a critical, essential, or fundamental feature or element. Therefore, the scope is not limited by anything other than the appended claims, wherein, unless expressly stated otherwise, references to elements in the singular do not mean "one and only one," but rather "one or more." Furthermore, where phrases like "at least one of A, B, or C" are used in the claims, it is intended to be interpreted as meaning that in an embodiment, a single A may exist, in an embodiment, a single B may exist, in an embodiment, a single C may exist, or in a single embodiment, any combination of elements A, B, or C may exist; for example, A and B, A and C, B and C, or A and B and C.

[0045] In the detailed description herein, references to "one embodiment," "an embodiment," "an example embodiment," etc., indicate that the described embodiment may include a particular feature, structure, or characteristic, but each embodiment may not necessarily include that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is proposed that such feature, structure, or characteristic be implemented, within the knowledge of those skilled in the art who benefit from this disclosure, in conjunction with other embodiments, whether explicitly described or not. After reading this specification, those skilled in the art should understand how this disclosure can be implemented in alternative embodiments.

[0046] Furthermore, elements, components, or method steps in this disclosure are not intended for public use, whether or not they are expressly stated in the claims. None of the elements of the claims herein should be construed under 35 U.S.SC §112(f) unless the element is expressly stated using the phrase “means for…”. As used herein, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not necessarily include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0047] Although this teaching has been described in conjunction with various embodiments and examples, it is not intended to be limited to these embodiments or examples. On the contrary, this teaching encompasses various alternatives, modifications, and equivalents, as will be apparent to those skilled in the art. Therefore, the foregoing description and figures are by way of example only.

Claims

1. A hybrid powertrain system, the hybrid powertrain system comprising: engine; At least one electric motor / generator MG; A clutch, the clutch being connected to the engine and the at least one MG; A transmission, the transmission being coupled to the at least one MG; An energy storage system, the energy storage system being connected to the at least one MG; as well as A controller, operatively coupled to the engine, the at least one MG, the clutch, the transmission, and the energy storage system, the controller including a processor and a memory, the memory including instructions that, when executed by the processor, cause the controller to: Initiate engine shutdown This allows the engine torque, and the torque associated with the at least one MG, to be reduced to zero or near zero. Shift the transmission to neutral. The at least one MG is operated in generator mode in neutral, thereby loading the engine via the clutch to recover kinetic energy from the engine. Disengage the clutch to separate the at least one MG from the engine. Increase the speed of the at least one MG to the target speed, and In response to the at least one MG reaching the target speed, the transmission shifts gears.

2. The hybrid powertrain system according to claim 1, wherein, The processor executing the instructions also causes the controller to use power from the at least one MG to propel the vehicle after shifting the transmission.

3. The hybrid powertrain system according to claim 2, wherein, The vehicle in question is a fully hybrid vehicle.

4. The hybrid powertrain system according to claim 2, wherein, The engine is an internal combustion engine.

5. The hybrid powertrain system according to claim 2, wherein, Initiating engine shutdown includes determining, based on input from at least one sensor, that power from the engine is not required to propel the vehicle.

6. The hybrid powertrain system according to claim 2, wherein, Shifting the transmission to neutral disengages at least one MG from the vehicle's final drive unit.

7. The hybrid powertrain system according to any one of claims 1 to 6, wherein, The processor executing the instructions also causes the controller to control the at least one MG to store energy recovered from the engine by the at least one MG in the energy storage system.

8. The hybrid powertrain system according to any one of claims 1 to 6, wherein, The energy storage system includes multiple batteries.

9. The hybrid powertrain system according to claim 1, wherein, Compared to when the engine is allowed to coast to zero or near-zero speed, the load applied to the engine by the at least one MG operating in the generator mode causes the engine to reach zero or near-zero speed more quickly.

10. The hybrid powertrain system according to claim 1, wherein, The processor executing the instructions also causes the controller to restart the engine to provide the additional torque in response to determining that additional torque is required.

11. A method for recovering energy from an engine in a hybrid powertrain comprising at least one electric motor / generator MG, the method comprising the steps of: Initiate engine shutdown; This allows the engine torque, and the torque associated with the at least one MG, to be reduced to zero or near zero; Shift the transmission connected to at least one MG to neutral; The at least one MG is operated in generator mode in the neutral position, thereby loading the engine through the clutch to recover kinetic energy from the engine; Disengage the clutch to separate the at least one MG from the engine; Increase the speed of at least one MG to the target speed; as well as In response to the at least one MG reaching the target speed, the transmission shifts gears.

12. The method according to claim 11, further comprising the following step: After the transmission is shifted, the vehicle is propelled using power from the at least one MG.

13. The method according to claim 12, wherein, The vehicle in question is a fully hybrid vehicle.

14. The method according to claim 12, wherein, The engine is an internal combustion engine.

15. The method according to claim 12, wherein, Initiating engine shutdown includes determining, based on input from at least one sensor, that power from the engine is not required to propel the vehicle.

16. The method according to claim 12, wherein, Shifting the transmission to neutral disengages at least one MG from the vehicle's final drive unit.

17. The method according to any one of claims 11 to 16, the method further comprising the step of: The energy recovered from the engine by the at least one MG is stored in an energy storage system connected to the at least one MG.

18. The method according to claim 17, wherein, The energy storage system includes multiple batteries.

19. A hybrid powertrain system, the hybrid powertrain system comprising: engine; At least one electric motor / generator MG; A first clutch is connected to the engine and the at least one MG; A second clutch is connected between the at least one MG and the final drive unit; An energy storage system, the energy storage system being connected to the at least one MG; as well as A controller, operatively coupled to the engine, the at least one MG, the first clutch, the second clutch, and the energy storage system, the controller including a processor and a memory, the memory including instructions that, when executed by the processor, cause the controller to: Initiate engine shutdown This allows the engine torque, and the torque associated with the at least one MG, to be reduced to zero or near zero. Engage the second clutch. The at least one MG is operated in generator mode while the second clutch is engaged, thereby loading the engine via the first clutch to recover kinetic energy from the engine. Disengage the first clutch to separate the at least one MG from the engine. Increase the speed of the at least one MG to the target speed, and In response to the at least one MG reaching the target speed, the second clutch is engaged.

20. The hybrid powertrain system of claim 19, further comprising a transmission coupled to the at least one MG, wherein, The processor executing the instructions also causes the controller to engage the at least one MG with the transmission in response to the disengagement of the at least one MG from the engine.

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