BELT DRIVE SYSTEM WITH FORWARD COUPLING TORSION LOAD ADJUSTMENT

Abstract

A belt drive system for an internal combustion engine is provided, rotatably coupled to a rotary motor. The internal combustion engine contains at least three cylinders, each with a piston that can be operated to rotate a crankshaft. The belt drive system includes a belt and a controller. The belt is coupled to the crankshaft of the internal combustion engine and the rotary motor; the controller is operationally connected to the rotary motor, and the controller causes data processing hardware to perform the following operations: applying a torque to the rotary motor; and changing the torque of the rotary motor prior to changing the rotational speed of the internal combustion engine in order to maintain a predetermined tension in the belt and to reduce any torsional response of the rotary motor, via the belt drive, to the torsional vibration input from the engine.

Description

INTRODUCTION

[0001] The information provided in this section is intended to provide a general context for the disclosure. The work of the presently named inventors, to the extent described in this section, as well as those aspects of the description that do not otherwise qualify as prior art at the time of filing, are neither expressly nor implicitly acknowledged as prior art to the present disclosure.

[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. A belt is coupled to the first pulley and the second pulley to transfer torque between the internal combustion engine and the rotary motor. In some aspects, for example, the torque is transferred from the internal combustion engine to the rotary motor, which converts it into electrical power to charge a battery. Alternatively, the torque is transferred from the rotary motor to the crankshaft to assist rotation of the crankshaft and thereby improve the efficiency of the internal combustion engine.

[0003] During operation, the crankshaft speed may be out of synchronization with the rotational motor speed, causing the rotational motor and the engine to operate out of phase with each other. This could lead to belt slack or increased stress on the belt. In such cases, a torsional vibration of the crankshaft caused by a change in the engine's momentum may impose a system load on the rotational motor. In the case where slack is present, for example, the torsional load is exerted when the rotational motor and crankshaft speeds equalize. Accordingly, it remains desirable to reduce the torsional load. SUMMARY

[0004] According to one configuration, a belt drive system is provided for an internal combustion engine rotatably coupled to a rotary motor. 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 path including a first pulley coupled to a crankshaft of the internal combustion engine and a second pulley coupled to the rotary motor. The belt drive system further includes a controller operatively connected to the rotary motor.The controller includes computing hardware and memory hardware, the memory hardware storing instructions that, when executed on the computing hardware, cause the computing hardware to perform operations including: applying torque to the rotation motor and changing the torque of the rotation motor prior to changing a speed of the internal combustion engine to maintain a predetermined tension in the belt and reduce a torsional response of the rotation motor via the belt to a torsional vibration input from the internal combustion engine.

[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 engine crankshaft acceleration.

[0006] According to one configuration, the controller is configured to reduce torque of the rotation motor prior to engine crankshaft deceleration. Additionally or alternatively, the controller may be configured to command the rotation motor to provide acceleration torque prior to piston expansion and regeneration torque prior to piston compression. The acceleration torque and regeneration torque may be asymmetric with respect to one another.

[0007] According to one configuration, the controller may be configured to maintain the torque of the rotary motor when a cylinder of the internal combustion engine is not firing. The controller may be configured to change the torque with respect to an angular position of the crankshaft. For example, the controller may be configured to change the torque when the crankshaft is between 42 and 50 degrees before top dead center. The belt drive system may further include a crankshaft sensor configured to detect the angular position of the crankshaft. Finally, the acceleration torque and the regeneration torque are asymmetric with respect to each other to maintain a net-zero energy balance.

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

[0009] The method may include one or more of the following features. For example, the torque of the rotary motor may be increased before a crankshaft acceleration of the internal combustion engine. Additionally or alternatively, the method may further include reducing a torque of the rotary motor before a crankshaft deceleration of the internal combustion engine.

[0010] According to one configuration, the spin motor may generate an acceleration torque prior to piston expansion and a regeneration torque prior to piston compression. According to such an aspect, the acceleration torque and the regeneration torque may be asymmetric with respect to one another. The torque of the spin motor may be maintained when a cylinder of the internal combustion engine is not firing. Additionally or alternatively, the method may include detecting an angular position of the crankshaft. According to such an aspect, the torque of the spin motor may change with respect to the angular position of the crankshaft. For example, the torque of the spin motor may be changed when the crankshaft is between 42 and 50 degrees before top dead center. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure; they show: Fig. 1A is a schematic view of a belt drive system according to the principles of the present disclosure; Fig. 1B is an illustrative view showing a vehicle having a Fig. 1A; Fig. 2 is a functional block diagram of an exemplary belt drive system according to the principles of the present disclosure for use in connection with the belt drive system of Fig. 1A; Fig. 3 is a diagram showing a profile of a torque command with respect to a position of a crankshaft; Fig. 4 is a diagram illustrating the modified torque command with respect to the torque command; Fig. 5 is a table showing the operation of the cylinders with respect to an engine cycle during a dynamic fuel management mode; and Fig. 6 is a flow chart showing the steps of a method for reducing torsional stress on a prime mover.

[0012] Corresponding reference numerals indicate corresponding parts throughout the drawings. DETAILED DESCRIPTION

[0013] Example configurations will now be described more fully with reference to the accompanying drawings. Example configurations are provided so that this 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 present disclosure. Those of ordinary skill in the art will appreciate that specific details need not be employed, that the example configurations may be embodied in many different forms, and that the specific details and example configurations should not be construed to limit the scope of the disclosure.

[0014] The terminology used herein is for the purpose of describing specific example configurations only and is not intended to be limiting. As used herein, the singular articles "a," "an," and "the" are intended to include the plural forms as well, 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 components, but do not preclude the presence or addition of one or more other features, one or more other steps, one or more other operations, one or more other elements, one or more other components, and / or groups thereof.The method steps, processes, and operations described herein should not be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as such. Additional or alternative steps may be used.

[0015] When an element or layer is described as being "on," "engaging with," "connected to," "attached to," or "coupled to" another element or layer, it may be directly on, engaging with, connected to, attached to, or coupled to the other element or layer, or there may be intervening elements or layers. Conversely, when an element is described as being "directly on," "directly engaging with," "directly connected to," "directly attached to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" as opposed to "directly between," "adjacent" as opposed to "directly adjacent," etc.).The term “and / or” as used herein includes any combination of one or more of the associated listed elements.

[0016] The terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or sections. These elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may only be used to distinguish one element, component, region, layer, or section from another region, layer, or section. Terms such as "first," "second," and other numerical terms do not imply a sequence or order unless clearly indicated by the context. Consequently, a first element, component, region, layer, or section coulddiscussed below may be referred to as a second element, component, region, layer, or section without departing from the teachings of the example configurations.

[0017] 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 group) that executes code; a memory (shared, dedicated, or group) that stores code executed by a processor; 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.

[0018] The term code, as used above, may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, and / or objects. The term shared processor includes a single processor that executes some or all of the code from multiple modules. The term group processor includes a processor that, in combination with additional processors, executes some or all of the code from one or more modules. The term shared memory includes a single memory that stores some or all of the code from multiple modules. The term group memory includes memory that, in combination with additional memory, stores some or all of the code from one or more modules. The term memory may be a subset of the term computer-readable medium.The term computer-readable medium does not encompass transitory electrical and electromagnetic signals propagating through a medium and can therefore be considered a tangible and non-transitory storage. Non-limiting examples of non-transitory storage include tangible computer-readable medium, including non-volatile memory, magnetic storage, and optical storage.

[0019] The devices and methods described in this application may be implemented partially or entirely 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.

[0020] A software application (i.e., a software resource) may refer to computer software that causes a computing device to perform a task. According to some examples, a software application may be referred to as an "application," an "app," or a "program." 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.

[0021] Non-transitory memory may include physical devices 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. The non-transitory memory may 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) / electronically erasable programmable read-only memory (EEPROM) (which, for example, is typically used for firmware, such as boot programs).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 disks or tapes.

[0022] These computer programs (also known as programs, software, software applications, or code) contain machine instructions for a programmable processor and may be implemented in a high-level procedural and / or object-oriented programming language and / or in an assembly / machine language. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, non-transitory computer-readable medium, device, and / or apparatus (e.g., magnetic disks, optical disks, memories, programmable logic devices (PLDs)) used to provide 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 used to provide machine instructions and / or data to a programmable processor.

[0023] Various implementations of the systems and techniques described herein may be embodied in digital electronic and / or optical circuitry, integrated circuitry, specially designed ASICs (Application Specific Integrated Circuits), computer hardware, firmware, software, and / or combinations. These various implementations may include implementation in one or more computer programs executable and / or interpretable on a programmable system including at least one programmable processor, which may be a special-purpose or general-purpose processor, coupled to receive data and instructions from, and send data and instructions to, a memory system, at least one input device, and at least one output device.

[0024] The processes and logic flows described in this specification may be performed by one or more programmable processors, also referred to as data processing hardware, that execute one or more computer programs to perform functions by acting on input data and generating output. The processes and logic flows may also be performed by special-purpose logic circuitry, such as an FPGA (field-programmable gate array) or an ASIC (application-specific integrated circuit). Processors suitable for executing a computer program include, by way of example, both general-purpose and special-purpose microprocessors and any one or more processors of any type of digital computer. Generally, a processor receives instructions and data from read-only memory or random access memory, or both.The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to, one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, for receiving data from them, sending data to them, or both. However, a computer is not required to include such devices. Computer-readable media suitable for storing instructions and data of a computer program include all forms of non-volatile memory, media, and storage devices, including, by way of 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 into special logic circuitry.

[0025] To provide interaction with a user, one or more aspects of the disclosure may be implemented in a computer having a display device, e.g., a CRT (cathode ray tube), an LCD (liquid crystal display monitor), or a touch screen, for displaying information to the user, and optionally a keyboard and a 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; feedback provided to the user may, for example, be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; while input from the user may be received in any form, including auditory, voice, or tactile input.Additionally, a computer may interact with a user by sending documents to and receiving documents from a device used by the user; e.g., by sending web pages to a web browser on a client device of the user in response to requests received from the web browser.

[0026] A system and method may process various engine and vehicle operating conditions to modify a torque command to reduce torsional loading on the engine and / or pulleys associated with the vehicle driveline. In one aspect, the modified torque command is forward fed to maintain a spin motor in phase with an engine. For example, the modified torque command is actuated by the spin motor to precede engine crankshaft acceleration.

[0027] Additionally, the system and method may be configured to time the processing of the modified torque command prior to piston expansion and piston compression, wherein a boost torque command is modified and processed prior to piston expansion and a generate torque command is modified and processed prior to piston compression. The modified torque command may be delivered to a selected piston or to all pistons based on an operating condition of the vehicle. For example, if the engine is operating in a dynamic fuel management state, the torque command is modified and applied to the active or otherwise firing piston.

[0028] Fig. 1A schematically illustrates a belt drive system 10 for transmitting torque between an internal combustion engine 12 (engine) and a rotary motor 14. According to one configuration, the engine 12 is configured to generate motive power for a drive train system 16 that is arranged in a (in Fig. 1B). For illustrative purposes, the vehicle 1 is shown as a heavy-duty truck, but it should be appreciated that the principles of the belt drive system 10 may be incorporated into any vehicle, including a passenger car, a light truck, a commercial vehicle, an agricultural vehicle, an industrial / warehouse vehicle, or a recreational off-road vehicle. The vehicle 1 may further include a hybrid operating system (HOS) 18 wherein a battery 2 may be used to assist in propelling the vehicle 1 as well as to power various vehicle loads. The HOS 18 may be configured, among other features, to balance the power transfer between the rotary motor 14 and the prime mover 12 to achieve a predetermined energy efficiency between the battery and the fuel.

[0029] The engine 12 may be a multi-cylinder internal combustion engine 12 having at least three cylinders that converts fuel into mechanical torque through a thermodynamic combustion process. The engine 12 is equipped with a plurality of actuators and sensor devices (not shown) for monitoring the operation of the engine 12 and for supplying fuel to generate combustion charges in the cylinders. The combustion charges generate an expansion force that is transmitted via pistons and connecting rods (not shown) to a crankshaft 20 to generate torque that drives the wheels of the vehicle 1.

[0030] The operation of the engine 12 and the rotation motor 14 is controlled by a controller unit 22. It should be appreciated that the controller unit 22 may consist of individual processing units including the HOS 18, an engine control unit 22a, and a motor torsion control unit 22b. The controller unit 22 performs processing to actuate the respective engine 12 and the respective rotation motor 14 in response to input from various vehicle components. For example, the controller unit 22 may increase or decrease fuel to the engine 12 in response to a pedal or brake command, or increase or decrease acceleration of the rotation motor 14 in response to the pedal or brake command.

[0031] The belt drive system 10 includes a belt drive 26 with a first pulley 28 and a second pulley 30. The first pulley 28 is mounted on the 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 stepped transmission configured to transmit the engine's speed and torque at one of several fixed gear ratios in response to operator inputs.

[0032] The engine 12 may include a solenoid-actuated low-voltage electric starter (not shown) that assists in starting the engine 12 in response to a key start event. The engine 12 may be configured to perform engine stop / start operations, including executing auto-start and auto-stop routines, during vehicle operation. The engine 12 may be configured to execute auto-start and auto-stop control routines, fuel cut-off (FCO) control routines, active fuel management routines, and dynamic fuel management, including cylinder deactivation control routines and cylinder skip-firing routines, during ongoing operation.

[0033] The second pulley 30 is attached to the front of the rotary motor 14. The rotary motor 14 may be any suitable electric motor / generator device that is electrically coupled to a DC power source via an inverter, according to one configuration. The rotary motor 14 may include a permanent magnet electric motor or, alternatively, 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 may be any high-voltage energy storage device, such as, without limitation, a multi-cell lithium-ion device, an ultracapacitor, or other suitable energy storage device. Alternatively, another non-combustion torque machine, such as, for example, a generator, may be used in place of the rotary motor 14.A pneumatically operated device or a hydraulically operated device may be used. By definition, a non-combustion torque machine is any device capable of generating torque by converting a potential energy source into kinetic energy without combustion of the potential energy. Non-limiting examples of potential energy sources may include electrical energy, pneumatic energy, and hydraulic energy.

[0034] The belt drive system 10 further includes a flexible, continuous serpentine belt 24 disposed within the belt track 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 tension pulley 32, first and second idler pulleys 34, 36, and a hydraulic strut tensioner 38 including a strut tensioner pulley 40, suitably positioned within the belt track 26 over which the serpentine belt 24 travels. Alternatively, the belt drive system 10 may include any suitable configuration including a serpentine belt 24 arranged to transmit torque between the prime mover 12 and the rotary motor 14, and including the hydraulic strut tensioner 38 described herein.

[0035] The controller unit 22 is in communication with the sensors and is also in communication with the actuators. As used herein, the term "controller unit 22" refers to an engine control module configured to process the information from the sensors to generate instructions, processes, and logic flows for operating the actuators to control the operation of the engine 12 and the electric machine in response to operator commands. It should be recognized that operator commands may move the rotation motor 14 out of phase with the engine 12 such that the speed of the rotation motor 14 is different from a speed of the crankshaft 20. The rotation motor 14 and the crankshaft 20 may be out of phase with each other for a variety of reasons. For example, the rotation motor 14 and the crankshaft 20 mayin response to a user-initiated braking command, a user-initiated acceleration command, or during active fuel management operations, and the like.

[0036] The controller unit 22 is operatively connected to the spin motor 14 and includes computing hardware 50 and memory hardware 52. The memory hardware 52 stores instructions that, when executed on the computing hardware 50, cause the computing hardware 50 to perform operations including applying torque to the spin motor 14 and changing the torque of the spin motor 14 prior to changing a speed of the engine 12 in order to maintain a predetermined tension in the belt 24 and reduce torsional stress on the engine 12. The controller unit 22 can process various vehicle operating conditions and parameters to change the torque of the spin motor 14 prior to changing the speed of the engine 12. For example, the controller unit 22 canchange the torque of the rotary motor 14 when the crankshaft 20 of the internal combustion engine 12 is operating within a predetermined range or band of revolutions per minute ("RPM") or a predetermined frequency. Furthermore, it should be recognized that the operating conditions and parameters may vary based on the size and type of the internal combustion engine 12. Accordingly, the controller unit 22 may change the torque of a rotary motor 14 coupled to a four-cylinder internal combustion engine 12 within an RPM range that differs from the RPM range of an eight-cylinder internal combustion engine 12.

[0037] In Fig. 2, a flowchart illustrating the operation of system 10 is provided. The operation of system 10 is controlled by controller unit 22. At block 100, a torsion control command is generated by a torsion control module 42. The torsion control command includes a set of instructions for rotation motor 14 to execute. The torsion control module 42 may be located within controller unit 22 or separately. The torsion control module 42 generates the torsion control command by processing a torque command generated by a component of vehicle operating system 10, such as HOS 18.

[0038] The HOS 18 may generate the torque command by processing various vehicle information to achieve one of several goals. For example, the torque command may be generated based on a goal to charge the battery in cases where the battery state of charge is below a predetermined threshold. However, in cases where the battery state of charge is below a predetermined threshold, but the vehicle's electrical load demand is also below a predetermined threshold, the HOS 18 goal may change to generate boost torque to drive the engine 12. Accordingly, it should be recognized that the torque command is a dynamic value that changes based on numerous factors, which, when processed, achieves an energy efficiency between the battery, fuel, and driving demands.

[0039] The torsion control command is transmitted to the rotation motor 14 to operate the rotation motor 14 according to the torsion control command. The torsion control command is calculated by the controller unit 22 based on the vehicle's operating conditions, such as engine speed, engine spark timing, manifold pressure, belt condition, crankshaft 20 angle, and the like. The vehicle's operating conditions may be detected using various sensors associated with the vehicle and vehicle components. In addition, the vehicle's operating conditions may be further processed to determine whether the vehicle is operating in a dynamic fuel management ("DFM" state) or an active fuel management ("AFM" state), where piston actuation is customized to achieve the DFM and AFM goals, respectively.It should be recognized that the listed operating conditions of the vehicle - upon which the torsion control command is based - are exemplary and do not constitute an exhaustive list of possible operating conditions that could be used by the controller unit 22 in determining the torsion control command.

[0040] The controller unit 22 processes the diagnostic tests to determine whether the torque command generated by the HOS 18 should be modified. For example, at block 102, the controller unit 22 processes a diagnostic test of the belt 24 to determine whether the belt 24 is slipping. The diagnostic test may be performed using a pulley sensor 44 or a strut tensioner sensor 46. If the belt 24 is slipping, the process returns to block 100, in which case the torque command is not modified.

[0041] A further diagnostic test is disclosed in block 104 wherein information from a 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 RPM range, the controller unit 22 proceeds to block 106. If the crankshaft 20 is operating outside the target RPM range, the process returns to block 100. It should be appreciated that the target RPM range may be based on various factors, including the size of the engine, the number of cylinders, the arrangement of the cylinders (i.e., in-line, V, etc.), the operating mode of the vehicle, and the like.

[0042] Another example of a diagnostic test is disclosed in block 106, wherein a vehicle operating mode is processed. In particular, the diagnostic test may be configured to determine the operating routine of the engine 12, such as the number of cylinders active during operation of the engine 12. For vehicles equipped with a DFM, for example, it is determined whether the vehicle is operating in a DFM mode. Regardless of whether the vehicle is operating in a DFM mode, the controller unit 22 modifies the torque command. In cases where the vehicle is operating in a DFM mode, the process continues to block 108, where the controller unit 22 modifies the torque command to adjust it for the active and inactive cylinders. The modified torque command is then transmitted to the spin motor 14 in block 112.In cases where the vehicle is not operating in a DFM mode, the process proceeds to block 110, where the controller unit 22 modifies the torque command to account for all cylinders. The modified torque command is then transmitted to the rotation motor 14 at block 112. It should be appreciated that the diagnostic test may also be performed to determine whether a vehicle is operating in an AFM mode.

[0043] For illustrative purposes, the belt drive system 10 will be discussed in the context of a hybrid vehicle having an internal combustion engine 12 with eight cylinders arranged in a V-shape coupled to the rotary motor 14. The belt 24 is disposed in a belt path 26 that includes a first pulley 28 coupled to the crankshaft 20 of the internal combustion engine 12 and a second pulley 30 coupled to the rotary motor 14. The vehicle includes the HOS 18 configured to balance the energy transfer between the engine 12 and the rotary motor 14 to charge the battery and assist in propelling the vehicle.

[0044] The belt drive system 10 further includes the controller unit 22, which is operatively connected to the rotation motor 14 and transmits instructions to the rotation 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 rotation motor 14 and changing the torque of the rotation motor 14 prior to changing a speed of the engine 12 in order to maintain a predetermined tension in the belt 24 and reduce the torsional response of the rotation motor via the belt drive to the torsional vibration input from the engine 12. The controller unit 22 may, for example,be configured to increase the torque of the rotation motor 14 prior to acceleration of the crankshaft 20 of the internal combustion engine 12. According to such an aspect, the controller unit 22 generates a torsion control command that is executed by the rotation motor 14. The torsion control command includes speed and direction commands and may be generated by a torque command issued by the HOS 18.

[0045] The torque command may be a generation torque or a boost torque. It should be recognized that either the generation torque or the boost torque may be modified. The system 10 not only considers the modification of a torque command, but also the timing of the execution of the modified torque command. For example, the controller unit 22 is configured to instruct the rotation motor 14 to provide a modified boost torque before a piston expansion event and a modified generation torque before a cylinder compression event. The modified boost torque and the modified generation torque may be asymmetric with respect to one another. For example, when the vehicleWhen operating in DFM mode and the engine 12 performs skip firing operations in which predetermined pistons are not fired, the values ​​of the modified boost torque and the modified generate torque differ from each other. Further, the timing at which the modified boost torque and the modified generate torque are processed by the spin motor 14 is synchronized with the skip firing operation of the engine 12. It should be appreciated that in some cases, the modified torque command may be configured to maintain the torque of the spin motor 14 when a cylinder of the engine 12 is not firing.

[0046] Fig. 3 illustrates a graph showing the achieved torque and RPM of crankshaft 20 with respect to the angle of crankshaft 20. The waveform showing the RPM of crankshaft 20 can be interpolated to show a compression and expansion cycle of the cylinder, where a peak of the waveform is an end of an expansion event of the cylinder and the trough of the waveform is an end of a compression event of the cylinder. Controller unit 22 can be configured to modify the torque command based on an angular position of crankshaft 20 and control rotation motor 14 to operate according to the modified torque command. It should be appreciated that the optimal angular position can be determined based on the configuration of system 10. For example, controller unit 22 is implemented in a four-cylinder vehicle with an HOS 18.According to such a configuration, the controller unit 22 may be configured to modify the torque command and process the modified torque command when the crankshaft 20 is between 42 and 50 degrees before top dead center. In the four-cylinder vehicle, the modified torque command is processed and actuated by the spin motor 14 when the crankshaft 20 is at approximately 45 degrees before top dead center. However, it should be appreciated that the timing at which the modified torque command is processed and actuated by the spin motor 14 may be based on various factors, including the engine and spark, speed, operating speed, atmospheric pressure, and the like. The belt drive system 10 may further include a crank sensor configured to detect the angular position of the crankshaft 20.

[0047] Fig. Figure 3 shows the measured modified torque command applied prior to cylinder expansion and cylinder compression. Specifically, it is shown how the measured torque increases to its maximum value prior to acceleration of the crankshaft 20 of the internal combustion engine 12, as indicated by an increase in the RPM of the crankshaft 20. The increase in the measured torque waveform corresponds to boost torque, while the decrease in the measured torque waveform corresponds to generation drive torque. Thus, Fig. 3, how the modified torque command instructs the rotation motor 14 to generate a modified boost torque command before cylinder combustion (as indicated by the peak of the waveform showing the RPMs of the crankshaft 20) and a modified generation torque command before cylinder compression (as indicated by the trough of the waveform showing the RPMs of the crankshaft 20).

[0048] As in Fig. 3, the modified torque command is actuated by the rotation motor 14 prior to piston expansion. Further, the torque achieved by the rotation motor 14 prior to piston expansion is applied when the position of the crankshaft 20 is approximately 45 degrees before top dead center. It should be appreciated by those skilled in the art that the timing of application of the modified torque command is based on the operating parameters (such as engine spark, engine speed, atmospheric pressure, etc.) of a four-cylinder engine and may vary from 45 degrees before top dead center. For example, application of the modified torque command may occur 47 degrees before top dead center for an eight-cylinder engine.

[0049] The modified torque command is actuated by the torque motor 14 to bring the torque motor 14 into phase with the engine 12 before the engine 12 and the torque motor 14 are phase-shifted. In this manner, the modified torque command reduces the torsional response of the torque motor 14, the load on the torque motor 14, which in turn reduces the torsional response of the torque motor via the belt drive to the torsional vibrations input from the engine 12. It should be appreciated that the controller unit 22 may be further configured to modify the torque command to reduce torsional loading on other components of the belt system 10. For example, according to vehicle configurations in which the belt system 10 may include a strut tensioner 38, the controller unit 22 maybe further configured to process a load on the strut tensioner 38 to modify the torque command to reduce a torsional load on the strut tensioner 38.

[0050] The controller unit 22 provides the torque motor 14 with an instruction to provide a boost torque (drive torque) or a regenerative torque (brake torque), which is transmitted to the engine 12 via the crankshaft 20 due to the connection to the belt 24. The controller unit 22 is further configured to process the vehicle's operating conditions to generate the boost torque command and the generate torque command, and to adjust the boost torque and generate torque prior to conditions that would result in a change in the tension of the belt 24 to maintain the belt 24 at a predetermined tension. The foregoing may be performed by the controller unit 22 by adjusting a speed of the torque motor 14 to reduce a torsional response of the torque motor via the belt drive 26 to the torsional vibrations input from the engine 12.

[0051] In Fig. 4, a description of the operation of the modified torque command is now provided. Fig. Figure 4 shows that the HOS 18 provides a torque command that is in a DC form. In one case, the torque command is a negative 15 Nm regenerative torque command. The waveform illustrates the modification of the torque command, which is in an AC form, where the torque is increased before a combustion event for a specific cylinder. The 15 Nm generation torque is modified to a 7.5 Nm torque command. That is, the area of ​​the waveform above the negative 15 Nm regenerative torque command corresponds to the modified boost torque command.To maintain vehicle efficiency, the modified boost torque command is the minimum torque required to bring the spin motor 14 into phase with the crankshaft 20, and is applied during a boost prior to cylinder expansion, not exceeding the torque command value of 7 Nm. According to this example, the area above and below the negative 15 Nm generate torque command is 22.5 Nm, with the area below the zero torque line being used to charge the battery. The generate torque command can be executed either by decelerating the spin motor 14 or by changing the direction of the spin motor 14. Energy is recovered through a modified generate torque command, which is the area of ​​the waveform below the negative 15 Nm generate torque command that occurs prior to a cylinder compression event.

[0052] Fig. Figure 4 illustrates a waveform of the modified torque command output by the HOS 18, where the modified torque command remains at 7.5 Nm, but the generation torque command is changed to negative 5 Nm. Specifically, the waveform on the right differs from the waveform on the left in both amplitude and length. However, the principles are the same in that the waveform with respect to the negative 5 Nm generation torque command is enlarged to correspond to the 7.5 Nm boost torque command, with the energy recovered by a modified generation torque command being the area of ​​the waveform below the negative 5 Nm generation torque command. In both cases, the modified boost torque command does not exceed the modified torque command value of 7.5 Nm.

[0053] Fig. 4 illustrates a modified torque command applied to a cylinder with a combustion and compression event (i.e., a firing cylinder). However, in the case where the vehicle is operating in a DFM or AFM mode, the torque command output by the HOS 18 is not modified for the cylinders that are not active. It should be appreciated that the modification of the torque command is not performed based on the operating conditions of the vehicle, as discussed above with respect to Fig. 2 has been revealed.

[0054] Fig. 5 illustrates tables of the cycles of the engine 12 of the exemplary vehicle described herein. In particular, the tables illustrate the engine cycle of the engine 12 operating in a DFM mode. In the DFM mode, based on the cycle of the engine 12, only certain cylinders are activated or firing, as indicated by the number "1." The cylinders that are not firing or inactive are indicated by the number "0." The torque command modification is performed only on the activated cylinders. The modified torque command may be configured to maintain the torque of the rotary motor 14 when a cylinder of the engine 12 is not firing. The torque command modification for each cylinder may not be the same to account for the number and timing of the inactive cylinders.Consequently, the modified boost torque and the modified generation torque are asymmetric with respect to each other to provide a neutral state of charge of the battery.

[0055] In Fig. 6, a method is provided for controlling the operation of a torque motor 14 rotatably coupled to an internal combustion engine 12 via a belt 24. The method includes, at block 200, actuating the torque motor 14 to apply torque to the internal combustion engine 12 via the belt 24. Actuating the torque motor 14 may be performed by the controller unit 22, which instructs the torque motor 14 to execute a torque command. As discussed above, the torque command may be generated by processing a torque command generated by a vehicle operating system 10, such as the HOS 18.

[0056] The method proceeds to block 202, where a change in a speed of the internal combustion engine 12 is determined or otherwise detected. The speed may be determined by processing various parameters of the engine 12 to calculate the speed of the crankshaft 20 of the engine 12, or it may be detected using conventional sensors, such as a crankshaft sensor 48.

[0057] The method includes, at block 208, changing the torque of the spin motor 14 prior to changing a speed of the engine 12. In one aspect, the torque of the spin motor 14 may be changed by modifying the torque command generated by the HOS 18. Preferably, the torque command is modified to generate a torque of the spin motor 14 that maintains a predetermined tension in the belt 24, thereby reducing a torsional response of the spin motor via the belt drive to the torsional vibration input from the engine 12.

[0058] The method may include performing a diagnostic test at block 204. The diagnostic test is configured to determine whether the operating conditions of the vehicle are suitable for modifying the torque command issued by the HOS 18. As described above with respect to Fig. 2, the system 10 may not modify the torque command in cases where the belt 24 is slipping or the RPMs of the crankshaft 20 are not within a predetermined threshold. At block 206, the method determines whether the conditions for modifying the torque command are present. If not, the torque command is not modified, and the method proceeds to block 200. If the conditions for modifying the torque command are present, the method proceeds to block 208.

[0059] According to one aspect of the method, the torque command is modified and executed by the rotation motor 14 to increase the torque of the rotation motor 14 prior to a crankshaft acceleration of the internal combustion engine 12. According to such an aspect, the controller unit 22 may process a change in the RPM of the crankshaft 20 to detect or otherwise determine the crankshaft acceleration.

[0060] As discussed above, the torque command may be a boost torque command or a generate torque command. The generate torque command may be an instruction to decelerate the spin motor 14 or may be an instruction to decrease torque of the spin motor 14 prior to crankshaft deceleration of the engine 12.

[0061] According to one aspect of the method, the modified torque command instructs the rotation motor 14 to generate the boost torque command prior to cylinder expansion, wherein the rotation motor 14 is accelerated prior to cylinder expansion. Furthermore, the modified torque command may instruct the rotation motor 14 to generate the generation torque command prior to cylinder compression, wherein the rotation motor 14 is decelerated or reversed prior to cylinder compression.

[0062] In yet another aspect, the modified boost torque command and the modified generation torque command are asymmetric with respect to each other. As discussed above, the modified boost torque command and the modified generation torque command may have a different value and timing based on the operation of the cylinders in a DFM mode or AFM mode, as shown in Fig. 5 is illustrated.

[0063] In one aspect, the torque command for a cylinder that is not actuated or operating is not modified. Consequently, the torque of the rotary motor 14 is maintained when a cylinder of the internal combustion engine 12 is not firing.

[0064] According to 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 rotation motor 14 based on the angular position of the crankshaft 20. For example, the torque command is modified, wherein the modified torque command is executed by the rotation motor 14 prior to cylinder expansion and, when the crankshaft 20 is between 42 and 50 degrees before top dead center, may be applied based on various engine operating parameters, such as ignition speed, operating speed, atmospheric pressure, and the like.

[0065] A system and method provided herein reduces a torsional response of a torque motor via the belt drive to the torsional vibrations input from the engine 12 by modifying a torque command prior to the occurrence of a torsional vibration of the engine 12. Specifically, the modified torque command is fed forward to keep the torque motor in phase with the crankshaft 20 of the engine 12. For example, the modified torque command is actuated by the torque motor to precede a crankshaft acceleration of the engine.The system and method consider various parameters and operating conditions of the vehicle, which may be processed to determine whether the torque command should be modified, determine the value of the modified torque, determine the timing of the generation of the modified torque, and determine which engine cylinder the modified torque should be applied to. For example, the system and method may be configured to time the processing of the modified torque command before piston expansion and piston compression, wherein a boost torque command is modified and processed before piston expansion, while a generate torque command is modified and processed before piston compression. The modified torque command may be delivered to a selected piston or to all pistons based on an operating condition of the vehicle.For example, if the engine is operating in a dynamic fuel management state, the torque command is modified and applicable to the one or more active or otherwise firing pistons.

[0066] A number of implementations have been described. It is recognized, however, that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

[0067] The foregoing description has been provided for purposes of illustration and description. It is not intended to be exhaustive or limiting of the disclosure. Individual elements or features of a particular configuration are generally not limited to that particular configuration, but are interchangeable and may be used in a selected configuration, even if not specifically shown or described. Furthermore, they may be varied in various ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

[1] A belt drive system for an internal combustion engine rotatably coupled to a rotary motor, the internal combustion engine including at least three cylinders, each of which includes a piston operable to rotate a crankshaft, the belt drive system comprising: a belt arranged in a belt path comprising a first pulley coupled to a crankshaft of the internal combustion engine and a second pulley coupled to the rotary motor; and a controller operatively connected to the rotary motor and including computing hardware and storage hardware, the storage hardware storing instructions that, when executed on the computing hardware, cause the computing hardware to perform operations including: Applying a torque to the rotary motor; and Changing the torque of the torque motor before changing a speed of the internal combustion engine in order to maintain a predetermined tension in the belt and to reduce a torsional reaction of the torque motor via the belt to a torsional vibration input from the engine. [2] The belt drive system of claim 1, wherein the controller is configured to increase the torque of the rotary motor prior to crankshaft acceleration of the internal combustion engine. [3] The belt drive system of claim 1, wherein the controller is configured to reduce torque of the rotary motor prior to crankshaft deceleration of the engine. [4] The belt drive system of claim 3, wherein the controller is configured to command the rotary motor to provide an acceleration torque prior to piston expansion and a regenerative torque prior to piston compression. [5] A belt drive system according to claim 4, wherein the acceleration torque and the regenerative 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 a cylinder of the internal combustion engine does not fire. [7] The belt drive system of claim 1, wherein the controller is configured to change the torque with respect to an angular position of the crankshaft. [8] The belt drive system of claim 7, wherein the controller is configured to change the torque when the crankshaft is between 42 and 50 degrees before the top dead center of the crankshaft. [9] The belt drive system of claim 8, further including a crankshaft sensor configured to detect the angular position of the crankshaft. [10] A belt drive system according to claim 5, wherein the acceleration torque and the regenerative torque are asymmetric with respect to each other to maintain a net zero energy balance.

Images