Belt drive system with feed-forward torsional load regulation

Abstract

A belt drive system for an internal combustion engine rotatably coupled to a rotary motor is provided. An internal combustion engine includes at least three cylinders each having a piston operable to rotate a crankshaft. The belt drive system includes a belt and a controller. The belt is coupled to a crankshaft of the internal combustion engine and the rotary motor; and the controller is operably connected to the rotary motor, wherein the controller causes the data processing hardware to perform the following operations: applying a torque to the rotary motor; and changing a torque of the rotary motor prior to a change in rotational speed of the internal combustion engine to maintain a predetermined tension in the belt and to reduce a rotary motor torsional response to torsional vibration input from the internal combustion engine by the belt drive.

Description

Technical Field

[0001] The information provided in this section is for the purpose of generally presenting the context of the present disclosure. The work of the presently named inventors, to the extent described in this section and in aspects of the description that may not otherwise be identified as prior art at the time of filing, is neither explicitly nor implicitly admitted to be prior art against the present disclosure. Background Art

[0002] The present disclosure generally relates to a belt drive system for coupling a rotary motor to an internal combustion engine. The belt drive system includes a first pulley coupled to the rotary motor and a second pulley coupled to a crankshaft of the internal combustion engine. The belt is coupled to the first pulley and the second pulley to transfer torque between the internal combustion engine and the rotary motor. For example, in some aspects, torque is transferred from the internal combustion engine to the rotary motor, which is converted into electricity to charge a battery. Alternatively, torque is transferred from the rotary motor to the crankshaft to assist in the rotation of the crankshaft, thereby improving the efficiency of the internal combustion engine.

[0003] In operation, the rotational speed of the crankshaft may be out of sync with the rotational speed of the rotary motor, causing the rotary motor and the internal combustion engine to operate out of phase with each other. This may result in belt slack or increased load on the belt. In this case, system loads may be applied to the rotary motor by torsional vibrations of the crankshaft caused by momentum changes of the engine. For example, in the presence of slack, torsional loads are applied when the rotational speeds of the rotary motor and the crankshaft are equal. Therefore, it is still desirable to reduce torsional loads. Summary of the invention

[0004] In one configuration, a belt drive system for an internal combustion engine rotatably coupled to a rotary motor is provided. The internal combustion engine includes at least three cylinders, each cylinder including a piston operable to rotate a crankshaft. The belt drive system includes a belt disposed in a belt run, the belt run including a first pulley coupled to the crankshaft of the internal combustion engine and a second pulley coupled to the rotary motor. The belt drive system also includes a controller operably connected to the rotary motor. The controller includes data processing hardware and memory hardware, the memory hardware storing instructions that, when executed on the data processing hardware, cause the data processing hardware to perform operations including: applying torque to the rotary motor and changing the torque of the rotary motor before a speed change of the internal combustion engine to maintain a predetermined tension in the belt and reduce a torsional response of the rotary motor to a torsional vibration input from the internal combustion engine through the belt.

[0005] The system may include one or more of the following optional features.For example, the controller may be configured to increase the torque of the rotary motor prior to acceleration of the crankshaft of the internal combustion engine.

[0006] In one configuration, the controller is configured to reduce the torque of the rotary motor before the crankshaft of the engine is decelerated. Additionally or alternatively, the controller may be configured to instruct the rotary motor to provide an acceleration torque before the piston expands and a regeneration torque before the piston compresses. The acceleration torque and the regeneration torque may be asymmetric relative to each other.

[0007] In one configuration, the controller can be configured to maintain torque of the rotary motor when cylinders of the internal combustion engine are not firing. The controller can be configured to vary the torque relative to the angular position of the crankshaft. For example, the controller can be configured to vary the torque when the crankshaft is between 42 degrees and 50 degrees before top dead center. The belt drive system can also include a crank sensor configured to detect the angular position of the crankshaft. Finally, the acceleration torque and the regeneration torque are asymmetric relative to each other to maintain a net zero energy balance.

[0008] In another configuration, a method for controlling operation of a rotary motor rotatably coupled to an internal combustion engine via a belt is provided. The method includes actuating the rotary motor to apply torque to the internal combustion engine through the belt, determining a change in rotational speed of the internal combustion engine, and varying the torque of the rotary motor prior to the change in rotational speed of the internal combustion engine to maintain a predetermined tension in the belt and reduce a torsional response of the rotary motor to a torsional vibration input from the internal combustion engine through the belt.

[0009] The method may include one or more of the following features. For example, the torque of the rotary motor may be increased before the crankshaft of the internal combustion engine is accelerated. Additionally or alternatively, the method may also include reducing the torque of the rotary motor before the crankshaft of the internal combustion engine is decelerated.

[0010] In one configuration, the rotary motor can generate an acceleration torque before the piston expands and a regenerative torque before the piston compresses. In such aspects, the acceleration torque and the regenerative torque can be asymmetric relative to each other. When the cylinders of the internal combustion engine do not fire, the torque of the rotary motor can be maintained. Additionally or alternatively, the method may include detecting the angular position of the crankshaft. In such aspects, the torque of the rotary motor can change relative to the angular position of the crankshaft. For example, when the crankshaft is between 42 degrees and 50 degrees before top dead center, the torque of the rotary motor can change. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings described herein are for illustrative purposes only of selected configurations and are not intended to limit the scope of the present disclosure.

[0012] Figure 1A is a schematic diagram of a belt drive system according to the principles of the present disclosure;

[0013] Figure 1B It is described including Figure 1AAn illustrative view of a vehicle with a drive system shown in ;

[0014] Figure 2 is a functional block diagram of an exemplary belt drive system according to the principles of the present disclosure, the exemplary belt drive system being used with Figure 1A Used in combination with a belt drive system;

[0015] Figure 3 is a graph showing a profile of torque command relative to crankshaft position;

[0016] Figure 4 is a graph depicting the corrected torque command relative to the torque command;

[0017] Figure 5 is a table showing operation of the cylinders relative to an engine cycle during a dynamic fuel management mode; and

[0018] Figure 6 is a flow chart showing the steps of a method for reducing torsional loads on an engine.

[0019] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0020] Example configurations will now be described more fully with reference to the accompanying drawings. Example configurations are provided so that the disclosure will be thorough and will fully convey the scope of the disclosure to those of ordinary skill in the art. Specific details, such as examples of specific components, devices, and methods, are set forth to provide a thorough understanding of the configurations of the disclosure. It will be apparent to those of ordinary skill in the art that specific details need not be employed, that example configurations may be implemented in many different forms, and that the specific details and example configurations should not be construed as limiting the scope of the disclosure.

[0021] The terms used herein are only used for the purpose of describing specific exemplary configurations and are not intended to be limiting. As used herein, the singular articles "a", "an" and "the" may also be intended to include plural forms unless the context clearly indicates otherwise. The terms "comprises", "comprising", "including" and "having" are inclusive and therefore specify the presence of features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts and / or groups thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0022] When an element or layer is referred to as being "on another element or layer," "engaged to," "connected to," "attached to," or "coupled to" another element or layer, it may be directly on, directly engaged with, connected to, attached to, or coupled to another element or layer, or there may be intermediate elements or layers. Conversely, when an element is referred to as being "directly on another element or layer," "directly engaged to," "directly connected to," "directly attached to," or "directly coupled to" another element or layer, there may be no intermediate elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more associated listed items.

[0023] The terms first, second, third, etc. can be used here to describe various elements, components, regions, layers and / or parts. These elements, components, regions, layers and / or parts should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or part from another region, layer or part. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence. Therefore, without departing from the teaching of the example structure, the first element, component, region, layer or part discussed below can be referred to as the second element, component, region, layer or part.

[0024] In this application, including the definitions below, the term module may be replaced by the term circuit. The term module may refer to, be part of, or include: an application specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor (shared, dedicated, or grouped) that executes code; a processor (shared, dedicated, or grouped) that stores code executed by a memory; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system on a chip.

[0025] The term code as used above may include software, firmware and / or microcode, and may refer to a program, a routine, a function, a class and / or an object. The term shared processor includes a single processor that executes some or all codes from multiple modules. The term group processor includes a processor that executes some or all codes from one or more modules in combination with an additional processor. The term shared memory includes a single memory that stores some or all codes from multiple modules. The term group memory includes a memory that stores some or all codes from one or more modules in combination with an additional memory. The term memory may be a subset of the term computer-readable medium. The term computer-readable medium does not include transient electrical signals and electromagnetic signals propagated through the medium, and therefore can be considered to be tangible and non-transient memory. Non-limiting examples of non-temporary memory include tangible computer-readable media, which include non-volatile memory, magnetic memory, and optical memory.

[0026] The devices and methods described in this application may be implemented in part or in whole by one or more computer programs executed by one or more processors. The computer programs include processor-executable instructions stored on at least one non-transitory tangible computer-readable medium. The computer programs may also include and / or rely on stored data.

[0027] Software applications (i.e., software resources) may refer to computer software that enables a computing device to perform tasks. Example applications include, but are not limited to, system diagnostic applications, system management applications, system maintenance applications, word processing applications, spreadsheet applications, messaging applications, media streaming applications, social networking applications, and gaming applications.

[0028] Non-transitory memory can be a physical device used to temporarily or permanently store programs (e.g., sequences of instructions) or data (e.g., program state information) for use by a computing device. Non-transitory memory can be volatile and / or non-volatile addressable semiconductor memory. Examples of non-volatile memory include, but are not limited to, flash memory and read-only memory (ROM) / programmable read-only memory (PROM) / erasable programmable read-only memory (EPROM) / electrically erasable programmable read-only memory (EEPROM) (e.g., commonly used for firmware, such as bootloaders). Examples of volatile memory include, but are not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase change memory (PCM), and disk or tape.

[0029] These computer programs (also referred to as programs, software, software applications, or code) include machine instructions for a programmable processor and may be implemented in high-level procedural and / or object-oriented programming languages ​​and / or assembly / machine languages. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, non-transitory computer-readable medium, apparatus, and / or device (e.g., disk, optical disk, processor, programmable logic device (PLD)) for providing machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor.

[0030] Various implementations of the systems and techniques described herein can be realized in digital electronic and / or optical circuits, integrated circuits, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations may include implementations in one or more computer programs executable and / or interpretable on a programmable system that includes at least one programmable processor, which may be special-purpose or general-purpose, coupled to receive data and instructions from a storage system, at least one input device, and at least one output device, and to send data and instructions to the storage system, at least one input device, and at least one output device.

[0031] The process and logic flow described in this specification can be performed by one or more programmable processors (also referred to as data processing hardware), which execute one or more computer programs to perform functions by operating on input data and generating outputs. The process and logic flow can also be performed by a dedicated logic circuit (e.g., FPGA (field programmable gate array) or ASIC (application-specific integrated circuit)). As an example, a processor suitable for executing a computer program includes both general-purpose and special-purpose microprocessors, and any one or more processors of any type of digital computer. Typically, the processor will receive instructions and data from a read-only memory or a random access memory or both. The basic elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more large-capacity storage devices (e.g., magnetic disks, magneto-optical disks, or optical disks) for storing data, or be operably connected to receive data from it or transmit data to it or both. However, a computer does not need to have such a device. Computer-readable media suitable for storing computer program instructions and data include all forms of nonvolatile memory, media, and memory devices, including, for example, semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD ROM and DVD-ROM disks. The processor and memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[0032] To provide interaction with a user, one or more aspects of the present disclosure may be implemented on a computer having a display device (e.g., a CRT (cathode ray tube), LCD (liquid crystal display) monitor, or touch screen) for displaying information to the user and optionally a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback, such as visual feedback, auditory feedback, or tactile feedback; and input from the user may be received in any form, including sound, voice, or tactile input. In addition, the computer may interact with the user by sending documents to and receiving documents from a device used by the user; for example, by sending a web page to a web browser on a user's client device in response to a request received from the web browser.

[0033] A system and method can process various engine and vehicle operating conditions to modify a torque command to reduce torsional loads on the engine and / or pulleys associated with the vehicle powertrain. In one aspect, the modified torque command is fed forward to keep the rotary motor in phase with the engine. For example, the modified torque command is actuated by the rotary motor to precede the crankshaft acceleration of the engine.

[0034] Additionally, the system and method can be configured to time the processing of the modified torque command prior to piston expansion and piston compression, wherein the boost torque command is modified and processed prior to piston expansion, and the boost torque command is modified and processed prior to piston compression. The modified torque command can be delivered to selected pistons or all pistons based on vehicle operating conditions. For example, if the engine is operating under dynamic fuel management conditions, the torque command is modified and applied to active or otherwise fired pistons.

[0035] Figure 1A Schematically illustrated is a belt drive system 10 for transmitting torque between an internal combustion engine 12 (engine) and a rotary motor 14. In one configuration, the engine 12 is configured to generate propulsion power for a transmission system 16 that is deployed in a vehicle 1 ( Figure 1B ). For illustrative purposes, vehicle 1 is shown as a heavy truck, but it should be understood that the principles of belt drive system 10 can be incorporated into any vehicle, including passenger cars, light vehicles, utility vehicles, agricultural vehicles, industrial / warehouse vehicles, or recreational off-road vehicles. Vehicle 1 may also include a hybrid operating system (HOS) 18, in which battery 2 can be used to assist in the propulsion of vehicle 1 as well as to power various vehicle loads. Among other features, HOS 18 can be configured to balance the power transfer between rotary motor 14 and engine 12 to achieve a predetermined energy efficiency between battery and fuel.

[0036] The engine 12 may be a multi-cylinder internal combustion engine 12 having at least three cylinders that convert fuel into mechanical torque through a thermodynamic combustion process. The engine 12 is equipped with a plurality of actuators and sensing devices (not shown) for monitoring the operation of the engine 12 and delivering fuel to produce a combustion charge in the cylinder. The combustion charge generates an expansion force that is transmitted to the crankshaft 20 via a piston and a connecting rod (not shown) to generate torque that drives the wheels of the vehicle 1.

[0037] The operation of the engine 12 and the rotary motor 14 is controlled by a controller unit 22. It should be understood that the controller unit 22 can be a separate processing unit that includes the HOS 18, the engine control unit 22a, and the motor torque control unit 22b. The controller unit 22 performs processing to actuate the corresponding engine 12 and rotary motor 14 in response to inputs from various vehicle components. For example, the controller unit 22 can increase or decrease the fuel to the engine 12 in response to a pedal or brake command, or increase or decrease the acceleration of the rotary motor 14 in response to a pedal or brake command.

[0038] The belt drive system 10 includes a belt run 26 having a first pulley 28 and a second pulley 30. The first pulley 28 is mounted on a crankshaft 20 of the engine 12. The crankshaft 20 may be coupled to a transmission (not shown) on the rear of the engine 12. The transmission may be a step gear transmission configured to transmit engine speed and torque in one of a plurality of fixed gear ratios in response to operator input.

[0039] The engine 12 may include a low-voltage, solenoid-actuated electric starter (not shown) that facilitates starting the engine 12 in response to a key-crank event. The engine 12 may be configured to perform engine stop / start operations, including performing auto-start and auto-stop routines during vehicle operation. The engine 12 may be configured to perform auto-start and auto-stop control routines, fuel cutoff (FCO) control routines, active fuel management routines, and dynamic fuel management (including cylinder deactivation control routines and cylinder skip firing routines) during ongoing operation.

[0040] The second pulley 30 is mounted at the front of the rotary motor 14. In one configuration, the rotary motor 14 can be any suitable electric motor / generator device electrically connected to a DC power source via an inverter. The rotary motor 14 can include a permanent magnet electric motor, or alternatively, can include an induction motor. The rotary motor 14 is configured to convert stored electrical energy into mechanical power and convert mechanical power into electrical energy. The DC power source can be any high-voltage energy storage device, such as a multi-battery cell lithium-ion device, a supercapacitor, or another suitable energy storage device, but is not limited thereto. Alternatively, another non-combustion torque machine (such as a pneumatic device or a hydraulic device) can be used to replace the rotary motor 14. As a definition, a non-combustion torque machine is any device that can generate torque by converting potential energy into kinetic energy without burning potential energy. Non-limiting examples of potential energy sources can include electrical energy, pneumatic energy, and hydraulic energy.

[0041] The belt drive system 10 also includes a flexible, continuous serpentine belt 24 disposed in the belt run 26. The belt drive system 10 may also include various conventional tensioning devices to reduce slack in the belt 24. For example, the belt drive system 10 may include a tensioner pulley 32, a first idler pulley 34, and a second idler pulley 36, and a hydraulic strut tensioner 38 including a strut tensioner pulley 40, which are appropriately positioned in the belt run 26 on which the serpentine belt 24 travels. Alternatively, the belt drive system 10 may include any suitable configuration including the serpentine belt 24, which is arranged to transmit torque between the engine 12 and the rotary motor 14, and including the hydraulic strut tensioner 38 described herein.

[0042] The controller unit 22 communicates with the sensors and also communicates with the actuators. As used herein, the term "controller unit 22" refers to an engine control module that is configured to process information from the sensors to generate instructions, processes, and logic flows for the operation of the actuators to control the operation of the engine 12 and the motors in response to operator commands. It should be understood that the operator command can cause the rotary motor 14 to be out of phase with the engine 12 so that the rotational speed of the rotary motor 14 is different from the rotational speed of the crankshaft 20. The rotary motor 14 and the crankshaft 20 can be out of phase with each other for a variety of reasons. For example, the rotary motor 14 and the crankshaft 20 can be out of phase in response to a user-initiated braking command, a user-initiated acceleration command, or during active fuel management operations, etc.

[0043] The controller unit 22 is operably connected to the rotary motor 14 and includes data processing hardware 50 and memory hardware 52. The memory hardware 52 stores instructions that, when executed on the data processing hardware 50, cause the data processing hardware 50 to perform operations including applying torque to the rotary motor 14 and changing the torque of the rotary motor 14 before the rotational speed of the internal combustion engine 12 changes to maintain a predetermined tension in the belt 24 and reduce the torsional load on the internal combustion engine 12. The controller unit 22 can process various vehicle operating conditions and parameters to change the torque of the rotary motor 14 before the rotational speed of the internal combustion engine 12 changes. For example, when the crankshaft 20 of the internal combustion engine 12 operates at a predetermined range or band of revolutions per minute ("RPM") or a predetermined frequency, the controller unit 22 can change the torque of the rotary motor 14. In addition, it should be understood that the operating conditions and parameters can change based on the size and type of the internal combustion engine 12. Therefore, the controller unit 22 can change the torque of the rotary motor 14 coupled to the four-cylinder internal combustion engine 12 in an RPM range different from the RPM range of the eight-cylinder internal combustion engine 12 .

[0044] Reference now Figure 2, a flow chart depicting the operation of the system 10 is provided. The operation of the system 10 is controlled by the controller unit 22. At box 100, a torque control command is generated by the torque control module 42. The torque control command includes a set of instructions for the rotation motor 14 to execute. The torque control module 42 may reside within the controller unit 22 or reside separately. The torque control module 42 generates the torque control command by processing the torque command generated by a component of the vehicle operating system 10, such as the HOS 18.

[0045] The HOS 18 can generate a torque command by processing various vehicle information to achieve one of a number of goals. For example, in the case where the battery's state of charge is below a predetermined threshold, the torque command can be generated based on a goal to charge the battery. However, in the case where the battery's state of charge is below a predetermined threshold but the vehicle's electrical load demand is also below a predetermined threshold, the goal of the HOS 18 can be changed to produce boost torque to drive the engine 12. Therefore, it should be understood that the torque command is a dynamic value that changes based on many factors, and when these factors are processed, energy efficiency between the battery, fuel, and driving demand is achieved.

[0046] The torque control command is transmitted to the rotary motor 14 to operate the rotary motor 14 according to the torque control command. The torque control command is calculated by the controller unit 22 based on vehicle operating conditions such as engine speed, engine ignition timing, manifold pressure, belt conditions, angle of the crankshaft 20, etc. The vehicle operating conditions can be detected by using various sensors associated with the vehicle and vehicle components. In addition, the vehicle operating conditions can also be processed to determine whether the vehicle is operating in a dynamic fuel management ("DFM") condition or an active fuel management condition ("AFM"), where the actuation of the piston is personalized to meet the goals of DFM and AFM, respectively. It should be understood that the listed vehicle operating conditions on which the torque control command is based are exemplary and do not constitute an exhaustive list of possible operating conditions that the controller unit 22 can use when determining the torque control command.

[0047] The controller unit 22 processes a diagnostic check to determine whether to modify the torque command generated by the HOS 18. For example, at box 102, the controller unit 22 processes a diagnostic check of the belt 24 to determine whether the belt 24 is slipping. The diagnostic check may be accomplished by using the pulley sensor 44 or the strut tensioner sensor 46. If the belt 24 is slipping, the process returns to box 100, in which case the torque command is not modified.

[0048] Another diagnostic check is disclosed at box 104, where information from the crankshaft sensor 48 is processed to determine the revolutions per minute ("RPM") of the crankshaft 20 and / or the position of the crankshaft 20. If the crankshaft 20 is operating within a target range of RPMs, the controller unit 22 proceeds to box 106. If the crankshaft 20 is operating outside of the target RPM range, the process returns to box 100. It should be understood that the target range of RPMs may be based on various factors, including engine size, number of cylinders, arrangement of cylinders (i.e., inline, V, etc.), driving mode of the vehicle, etc.

[0049] Another example of a diagnostic check is disclosed at box 106, where the vehicle operating mode is processed. In particular, the diagnostic check can be configured to determine the operating routine of the engine 12, such as the number of cylinders that are active during the operation of the engine 12. For example, for a vehicle equipped with DFM, it is determined whether the vehicle is operating in DFM mode. Regardless of whether the vehicle is operating in DFM mode, the controller unit 22 corrects the torque command. In the case where the vehicle is operating in DFM mode, the process proceeds to box 108, where the controller unit 22 corrects the torque command to adjust for active cylinders and inactive cylinders. Then, at box 112, the corrected torque command is transmitted to the rotary motor 14. In the case where the vehicle is not operating in DFM mode, the process proceeds to box 110, where the controller unit 22 corrects the torque command to take into account all cylinders. Then, at box 112, the corrected torque command is transmitted to the rotary motor 14. It should be understood that a diagnostic check can also be performed to determine whether the vehicle is operating in AFM mode.

[0050] For purposes of illustration, the belt drive system 10 is discussed in the context of a hybrid vehicle having an internal combustion engine 12 with eight cylinders arranged in a V-shape and coupled to a rotary motor 14. A belt 24 is disposed in a belt run 26 that includes a first pulley 28 coupled to a crankshaft 20 of the internal combustion engine 12 and a second pulley 30 coupled to the rotary motor 14. The vehicle includes a HOS 18 that is configured to balance energy transfer between the engine 12 and the rotary motor 14 to charge the battery and assist in propulsion of the vehicle.

[0051] The belt drive system 10 also includes a controller unit 22 that is operably connected to the rotary motor 14 and transmits instructions to the rotary motor 14. The controller unit 22 includes data processing hardware 50 and memory hardware 52. The memory hardware 52 stores instructions that, when executed on the data processing hardware 50, cause the data processing hardware 50 to perform operations including applying torque to the rotary motor 14 and changing the torque of the rotary motor 14 before the rotational speed of the internal combustion engine 12 changes to maintain a predetermined tension in the belt 24 and reduce the rotary motor torsional response to the torsional vibration input from the internal combustion engine 12 through the belt drive. For example, the controller unit 22 can be configured to increase the torque of the rotary motor 14 before the crankshaft 20 of the internal combustion engine 12 is accelerated. In such an aspect, the controller unit 22 generates a torsional control instruction that is executed by the rotary motor 14. The torsional control instruction includes a rotational speed and direction command and can be generated by a torque command issued by the HOS 18.

[0052] The torque command may be one of a generating torque and a boost torque. It should be understood that the generating torque or the boost torque may be corrected. The system 10 not only takes into account the correction of the torque command, but also the execution timing of the corrected torque command. For example, the controller unit 22 is configured to instruct the rotary motor 14 to provide a corrected boost torque before the piston expands and to provide a corrected generating torque before the cylinder compression event. The corrected boost torque and the corrected generating torque may be asymmetric relative to each other. For example, when the vehicle is operated in a DFM mode and the engine 12 performs a skip ignition operation in which a predetermined piston is not ignited, the values ​​of the corrected boost torque and the corrected generating torque are different from each other. Further, the timing of the rotary motor 14 processing the corrected boost torque and the corrected generating torque is synchronized with the skip ignition operation of the engine 12. It should be understood that in some cases, the corrected torque command may be configured to maintain the torque of the rotary motor 14 when the cylinders of the internal combustion engine 12 are not ignited.

[0053] Figure 3A graph showing the achieved torque and the RPM of the crankshaft 20 relative to the angle of the crankshaft 20 is depicted. The waveform showing the RPM of the crankshaft 20 can be interpolated to show the compression and expansion cycle of the cylinder, where the peak of the waveform is the end of the expansion event of the cylinder, and the trough of the waveform is the end of the compression event of the cylinder. The controller unit 22 can be configured to modify the torque command based on the angular position of the crankshaft 20 and control the rotary motor 14 to operate according to the modified torque command. It should be understood that the optimal angular position can be determined based on the configuration of the system 10. For exemplary purposes, the controller unit 22 is implemented in a four-cylinder vehicle with HOS18. In such a configuration, the controller unit 22 can be configured to modify the torque command and process the modified torque command when the crankshaft 20 is between 42 degrees and 50 degrees before the top dead center. In a four-cylinder vehicle, the modified torque command is processed and actuated by the rotary motor 14 when the crankshaft 20 is approximately 45 degrees before the top dead center. However, it should be appreciated that the timing of processing and actuating the modified torque command by the rotary motor 14 may be based on various factors to include engine and spark, speed, operating speed, barometric pressure, etc. The belt drive system 10 may also include a crank sensor configured to detect the angular position of the crankshaft 20 .

[0054] Figure 3 The measured corrected torque command applied prior to cylinder expansion and cylinder compression is shown. In particular, the measured torque is shown increasing to its peak value prior to acceleration of the crankshaft 20 of the internal combustion engine 12, as indicated by the increase in the RPM of the crankshaft 20. The rise in the waveform of the measured torque is commensurate with the boost torque, and the fall in the waveform of the measured torque is commensurate with the generated drive torque. Thus, Figure 3 The diagram shows how the modified torque command instructs the rotary motor 14 to generate a modified boost torque command prior to cylinder combustion (as indicated by the peaks of the waveform showing the RPM of the crankshaft 20) and to generate a modified generated torque command prior to cylinder compression (as indicated by the troughs of the waveform showing the RPM of the crankshaft 20).

[0055] like Figure 3 As shown, the modified torque command is actuated by the rotary motor 14 before the piston expands. In addition, when the crankshaft 20 position is approximately 45 degrees before top dead center, the torque achieved by the rotary motor 14 before the piston expands is applied. It should be understood by those skilled in the art that the timing of applying the modified torque command is based on the operating parameters of the four-cylinder engine (e.g., engine spark, engine speed, atmospheric pressure, etc.) and can deviate from 45 degrees before top dead center. For example, the application of the modified torque command can be 47 degrees before top dead center of the eight-cylinder engine.

[0056] The modified torque command is actuated by the rotary motor 14 to bring the rotary motor 14 into phase with the engine 12 before the engine 12 and the rotary motor 14 become out of phase. In doing so, the modified torque command reduces the torsional response of the rotary motor 14, the load on the rotary motor 14, which in turn reduces the rotary motor torsional response to the torsional vibration input from the engine 12 through the belt drive. It should be understood that the controller unit 22 can also be configured to modify the torque command to reduce the torsional load on other components of the belt system 10. For example, in a vehicle configuration where the belt system 10 may include a strut tensioner 38, the controller unit 22 can also be configured to process the load on the strut tensioner 38 to modify the torque command to reduce the torsional load on the strut tensioner 38.

[0057] The controller unit 22 provides instructions to the rotary motor 14 to provide a boost torque (driving torque) or a regenerative torque (braking torque), which is transmitted to the engine 12 through the crankshaft 20 by means of a connection with the belt 24. The controller unit 22 is also configured to process vehicle operating conditions to generate a boost torque command and a regenerative torque command, and to adjust the boost torque and the regenerative torque in advance of conditions that will cause a change in the tension of the belt 24 to maintain the belt 24 at a predetermined tension. The foregoing can be achieved by the controller unit 22 by adjusting the rotational speed of the rotary motor 14 to reduce the rotary motor torsional response to the torsional vibration input from the internal combustion engine 12 through the belt drive 26.

[0058] Reference now Figure 4 , a description of the operation of the modified torque command is provided. Figure 4 HOS 18 is shown to provide a torque command in DC form. In one example, the torque command is a regenerative torque command of negative 15Nm. The waveform shows a correction of the torque command in AC form, where the torque is increased before the combustion event of a specific cylinder. The 15Nm generated torque is corrected to a 7.5Nm torque command. That is, the waveform area above the negative 15Nm regenerative torque command is commensurate with the corrected boost torque command. In order to maintain the efficiency of the vehicle, the corrected boost torque command is the minimum torque required to make the rotary motor 14 in phase with the crankshaft 20, applied with boost before the cylinder expands, and does not exceed the torque command value of 7Nm. In this example, the area above and below the negative 15Nm generated torque command is 22.5Nm, where the area below the zero torque line is used to charge the battery. The generated torque command can be achieved by decelerating the rotary motor 14 or changing the direction of the rotary motor 14. Energy is recovered by the corrected generated torque command, which is the waveform area below the negative 15Nm generated torque command, which occurs before the compression event of the cylinder.

[0059] Figure 4The waveform of the modified torque command issued by the HOS 18 is depicted, where the modified torque command remains at 7.5 Nm, but the generating torque command is changed to negative 5 Nm. In particular, the waveform on the right is different from the waveform on the left in terms of amplitude and length. However, the principle is the same, in that the waveform is increased relative to the negative 5 Nm generating torque command to meet the 7.5 Nm boost torque command, and energy is recovered by the modified generating torque command, which is the area of ​​the waveform below the negative 5 Nm generating torque command. In both cases, the modified boost torque command does not exceed the modified torque command value of 7.5 Nm.

[0060] Figure 4 The modified torque command applied to the cylinder having the combustion and compression event (i.e., the firing cylinder) is depicted. However, in the case where the vehicle is operating in DFM or AFM mode, the torque command issued by the HOS 18 is not modified for the inactive cylinders. It should be understood that the modification of the torque command is not as described above with reference to FIG. Figure 2 The disclosed method is performed based on the operating conditions of the vehicle.

[0061] Figure 5 A table depicting an engine 12 cycle of an exemplary vehicle described herein. In particular, an engine cycle of the engine 12 operating in DFM mode is shown. In DFM mode, only certain cylinders are activated or firing, as indicated by the number "1" based on the cycle of the engine 12. Unfired or inactive cylinders are represented by the number "0". Correction of the torque command is performed only on the activated cylinders. The corrected torque command can be configured to maintain the torque of the rotary motor 14 when the cylinders of the internal combustion engine 12 are not firing. The correction of the torque command of the corresponding cylinders may not be the same to account for the number and timing of the inactive cylinders. Therefore, the corrected boost torque and the corrected generated torque are asymmetric relative to each other to provide a neutral charge state of the battery.

[0062] Reference now Figure 6 , a method for controlling the operation of a rotary motor 14 is provided, the rotary motor 14 being rotatably coupled to an internal combustion engine 12 via a belt 24. The method includes actuating the rotary motor 14 at box 200 to apply torque to the internal combustion engine 12 via the belt 24. Actuating the rotary motor 14 may be accomplished by a controller unit 22, which instructs the rotary motor 14 to execute a torque command. As described above, the torque command may be generated by processing a torque command generated by a vehicle operating system 10, such as the HOS 18.

[0063] The method proceeds to block 202 where a change in the rotational speed of the internal combustion engine 12 is determined or otherwise detected. The rotational speed may be determined by processing various engine 12 parameters to calculate the rotational speed of the crankshaft 20 of the engine 12, or may be detected using a conventional sensor such as the crankshaft sensor 48.

[0064] The method includes changing the torque of the rotary motor 14 prior to changing the rotational speed of the internal combustion engine 12 at box 208. In one aspect, the torque of the rotary motor 14 can be changed by modifying the torque command generated by the HOS 18. Preferably, the torque command is modified to produce a torque of the rotary motor 14 that maintains a predetermined tension in the belt 24, thereby reducing the rotary motor torsional response to the torsional vibration input from the engine 12 through the belt drive.

[0065] The method may include performing a diagnostic check at block 204. The diagnostic check is configured to determine whether vehicle operating conditions are appropriate for modifying the torque command issued by the HOS 18. Figure 2 As discussed, in the event that the belt 24 slips or the RPM of the crankshaft 20 is not within a predetermined threshold, the system 10 may not modify the torque command. At box 206, the method determines whether there are conditions for modifying the torque command. If not, the torque command is not modified and the method proceeds to box 200. If there are conditions for modifying the torque command, the method proceeds to box 208.

[0066] In one aspect of the method, the torque command is modified and executed by the rotary motor 14 to increase the torque of the rotary motor 14 before the crankshaft of the internal combustion engine 12 is accelerated. In such an aspect, the controller unit 22 can process the change in the RPM of the crankshaft 20 to detect or otherwise determine the crankshaft acceleration.

[0067] As discussed above, the torque command may be one of a boost torque command or a generator torque command. The generator torque command may be a command to decelerate the rotary motor 14 or may be a command to reduce the torque of the rotary motor 14 before the crankshaft of the internal combustion engine 12 is decelerated.

[0068] In one aspect of the method, the modified torque command instructs the rotary motor 14 to generate a boost torque command before the cylinder expands, wherein the rotary motor 14 accelerates before the cylinder expands. The modified torque command may also instruct the rotary motor 14 to generate the boost torque command before the cylinder compresses, wherein the rotary motor 14 decelerates or reverses before the cylinder compresses.

[0069] In yet another aspect, the modified boost torque command and the modified resulting torque command are asymmetric with respect to each other. As discussed above, based on the cylinder being operated in the DFM mode or the AFM mode, the modified boost torque command and the modified resulting torque command may have different values ​​and different timings, such as Figure 5 shown.

[0070] In one aspect, the torque command is not modified for cylinders that are not actuated or operated. Thus, when cylinders of the internal combustion engine 12 are not firing, the torque of the rotary motor 14 is maintained.

[0071] In yet another aspect of the method, the angular position of the crankshaft 20 is detected. The angular position of the crankshaft 20 may be detected using a crankshaft sensor 48. The torque command may be modified and executed by the rotary motor 14 based on the angular position of the crankshaft 20. For example, based on various engine operating parameters (such as spark speed, operating speed, atmospheric pressure, etc.), the torque command is modified and the modified torque command is executed by the rotary motor 14 before cylinder expansion and may be applied when the crankshaft 20 is between 42 degrees and 50 degrees before top dead center.

[0072] The systems and methods provided herein reduce the rotary motor torsional response to the torsional vibration input from the engine 12 through the belt drive by correcting the torque command before the torsional vibration of the engine 12 occurs. In particular, the corrected torque command is fed forward to keep the rotary motor in phase with the crankshaft 20 of the engine 12. For example, the corrected torque command is actuated by the rotary motor to precede the crankshaft acceleration of the engine. The system and method contemplate various vehicle parameters and operating conditions that can be processed to determine whether the torque command should be corrected, the value of the corrected torque, the timing of generating the corrected torque, and which engine cylinder the corrected torque should be applied to. For example, the system and method can be configured to time the processing of the corrected torque command before piston expansion and piston compression, wherein the boost torque command is corrected and processed before the piston expands, and the generating torque command is corrected and processed before the piston compresses. The corrected torque command can be delivered to selected pistons or all pistons based on the operating conditions of the vehicle. For example, if the engine is operating under dynamic fuel management conditions, the torque command is corrected and applied to active or otherwise fired pistons.

[0073] Many embodiments have been described. However, it should be understood that various modifications can be made without departing from the spirit and scope of the present disclosure. Therefore, other embodiments are within the scope of the following claims.

[0074] The foregoing description is provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present disclosure. The individual elements or features of a particular configuration are generally not limited to that particular configuration, but are interchangeable where applicable and can be used in a selected configuration, even if not specifically shown or described. It can also be varied in many ways. Such variations should not be considered as departing from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.

Claims

1. A belt drive system for an internal combustion engine rotatably coupled to a rotary motor, the internal combustion engine comprising at least three cylinders, each cylinder having a piston operable to rotate a crankshaft, the belt drive system comprising: a belt disposed in a belt running portion, the belt running portion including a first pulley coupled to a crankshaft of the internal combustion engine and a second pulley coupled to the rotary motor; as well as a controller operably connected to the rotary motor and comprising data processing hardware and memory hardware storing instructions that, when executed on the data processing hardware, cause the data processing hardware to perform operations comprising: applying torque to the rotary motor; as well as The torque of the rotary motor is varied prior to a change in rotational speed of the internal combustion engine to maintain a predetermined tension in the belt and reduce a rotary motor torsional response to a torsional vibration input from the engine through the belt. 2 . The belt drive system of claim 1 , wherein the controller is configured to increase the torque of the rotary motor prior to acceleration of a crankshaft of the internal combustion engine.

3. The belt drive system of claim 1, wherein the controller is configured to reduce the torque of the rotary motor before the crankshaft of the engine is decelerated. 4 . The belt drive system of claim 3 , wherein the controller is configured to instruct the rotary motor to provide an acceleration torque prior to piston expansion and a regeneration torque prior to piston compression.

5. The belt drive system of claim 4, wherein the acceleration torque and the regeneration torque are asymmetric with respect to each other.

6. The belt drive system of claim 1, wherein the controller is configured to maintain torque of the rotary motor when cylinders of the internal combustion engine are not firing.

7. The belt drive system of claim 1, wherein the controller is configured to vary the torque relative to an angular position of the crankshaft.

8. The belt drive system of claim 7, wherein the controller is configured to vary the torque when the crankshaft is between 42 degrees and 50 degrees before top dead center of the crankshaft.

9. The belt drive system of claim 8, further comprising a crank sensor configured to detect an angular position of the crankshaft.

10. The belt drive system of claim 5, wherein the acceleration torque and the regeneration torque are asymmetric with respect to each other to maintain a net zero energy balance.

Images