Shaft torque response system and method

Abstract

The powertrain system is controlled to deliver axle torque in response to operator accelerator pedal input. The axle torque is determined from a metric that includes historical control information, current control information, and future control information.

Description

Technical Field

[0001] This disclosure relates to shaft torque response systems and methods. Background Technology

[0002] The statements in this section are provided only as background information in relation to this disclosure. Therefore, these statements are not intended to constitute an admission of prior art.

[0003] Vehicles employ various propulsion systems in multiple configurations, which generate traction power in response to operator requests and transmit this power to the drivetrain. Accelerator pedal position and its changes are monitored and processed to provide the torque requests met by the powertrain. Changes in accelerator pedal position roughly correspond to changes in acceleration expected by the operator, and thus to axle torque requirements. However, accurate interpretation of accelerator pedal activity is challenging and can lead to undesirable performance effects, particularly in systems capable of achieving large torque changes very quickly (e.g., electric, hybrid electric, large diesel internal combustion, turbocharged gasoline internal combustion, etc.). Interpreting changes in accelerator pedal position to accurately reflect the operator's true intent is a laborious task performed during vehicle development through iterative in-vehicle calibration sessions. Summary of the Invention

[0004] In one exemplary embodiment, the method for powertrain control may include comparing a torque request from an operator with powertrain torque control, and latching a first reference torque to a first predetermined value when the deviation between the torque request and the torque control signal is greater than a predetermined amount. Shaft torque may be controlled based on the difference between the torque request and the first reference torque.

[0005] In addition to one or more features described herein, controlling the powertrain torque based on the difference between the torque request and the first reference torque may include: establishing a threshold based on the difference between the torque request and the first reference torque, latching a second reference torque to a second predetermined value when the deviation between the torque request and the torque control signal is greater than the threshold, and controlling the shaft torque based on the difference between the torque request and the second reference torque.

[0006] In addition to one or more features described herein, controlling shaft torque based on the difference between the torque request and the first reference torque may include referencing a calibration library that correlates torque variation with the rate of torque variation.

[0007] In addition to one or more features described herein, controlling shaft torque based on the difference between the torque request and the second reference torque may include referencing a calibration library that correlates torque variation with the rate of torque variation.

[0008] In addition to one or more features described in this article, the calibration library can be defined by driving modes.

[0009] In addition to one or more features described herein, the method may further include: tracking the first reference torque to the shaft torque when the deviation between the torque request and the torque control signal is not greater than the predetermined amount.

[0010] In addition to one or more features described herein, the method may further include: tracking the second reference torque to the shaft torque when the deviation between the torque request and the torque control signal is not greater than the threshold.

[0011] In addition to one or more features described herein, the method may further include: delaying the control of powertrain torque based on the difference between a torque request and a second reference torque during shaft torque intervention, and, after shaft torque intervention, starting the control of powertrain torque based on the difference between a torque request and a second reference torque with an initial shaft torque corresponding to the final shaft torque at the completion of the intervention.

[0012] In addition to one or more features described herein, the first predetermined value may include a shaft torque value that exists when the initial deviation between the torque request and torque control signals is greater than a predetermined amount.

[0013] In addition to one or more features described herein, the second predetermined value may include a shaft torque value that exists when the initial deviation between the torque request and torque control signals is greater than a threshold.

[0014] In another exemplary embodiment, the vehicle may include a powertrain system and a control system. The powertrain system has at least one actuator for controlling axle torque. The control system has a control module including a set of instructions executable to compare a torque request from an operator with a powertrain torque control signal. When the deviation between the torque request and the torque control signal is greater than a predetermined amount, a first reference torque is latched to a first predetermined value. The first predetermined value corresponds to an axle torque value present when the initial deviation between the torque request and the torque control signal is greater than the predetermined amount. A threshold is established based on the difference between the torque request and the first reference torque. When the deviation between the torque request and the torque control signal is greater than the threshold, a second reference torque is latched to a second predetermined value, which corresponds to an axle torque value present when the initial deviation between the torque request and the torque control signal is greater than the threshold. The at least one actuator is controlled based on the difference between the torque request and the second reference torque.

[0015] In addition to one or more features described herein, controlling at least one actuator based on the difference between a torque request and a second reference torque may include referencing a calibration library via the difference between the torque request and the second reference torque, the calibration library relating torque variation to the rate of torque variation.

[0016] In addition to one or more features described in this article, the calibration library can be defined by driving modes.

[0017] In addition to one or more features described herein, the instruction set can also be executed to track a first reference torque to the shaft torque when the deviation between the torque request and the torque control signal is no greater than a predetermined amount.

[0018] In addition to one or more features described herein, the instruction set can be further executed to track the second reference torque to the shaft torque when the deviation between the torque request and torque control signals is no greater than a threshold.

[0019] In addition to one or more features described herein, the instruction set may also execute to delay control of at least one actuator during shaft torque intervention based on the difference between the torque request and the second reference torque, and after shaft torque intervention, to initiate control of at least one actuator with an initial shaft torque value based on the difference between the torque request and the second reference torque, the initial shaft torque value corresponding to the final shaft torque value at the time of intervention completion.

[0020] In another exemplary embodiment, a method for powertrain control may include: receiving accelerator pedal position and vehicle speed information from an accelerator pedal at a control module; calculating a driver torque target at the control module based on the accelerator pedal position and vehicle speed; calculating a deviation between the driver torque target and a forming torque request at the control module; comparing the deviation with a first calibration threshold at the control module; latching a basic reference torque to a first predetermined value at the control module when the deviation exceeds the first calibration threshold, the first predetermined value corresponding to the forming torque request when the deviation initially exceeds the first calibration threshold; tracking the basic reference torque to the forming torque request at the control module when the deviation does not exceed the first calibration threshold; calculating a basic driver intent as the difference between the driver torque target and the basic reference torque at the control module; and referencing a second calibration threshold as the basic reference torque at the control module. The driver's intention is a function of the following: The deviation is compared with a second calibration threshold at the control module; when the deviation exceeds the second calibration threshold, the true reference torque is latched at the control module to a second predetermined value, the second predetermined value corresponding to the forming torque request when the deviation initially exceeds the second calibration threshold; when the deviation does not exceed the second calibration threshold, the true reference torque is tracked to the forming torque request at the control module; the true driver intention is calculated at the control module as the difference between the driver's torque target and the true reference torque; a calibration table library is referenced at the control module against the driver's true intention, and a torque acceleration request is returned, the calibration table library relating torque change to torque change rate; a forming torque request is determined at the control module based on the driver's torque target limited by the torque acceleration request; and at least one actuator is controlled by the control module based on the forming torque request to control shaft torque.

[0021] In addition to one or more features described in this article, the calibration library can be defined by driving modes.

[0022] The above-described features and advantages, as well as other features and advantages, of this disclosure will become apparent when taken in conjunction with the accompanying drawings and the following detailed description. Attached Figure Description

[0023] Other features, advantages, and details appear only by way of example in the following detailed description, which refers to the accompanying drawings, wherein:

[0024] Figure 1 An exemplary powertrain system according to this disclosure is shown;

[0025] Figure 2 A functional block diagram of certain aspects of an exemplary control system according to this disclosure is shown;

[0026] Figure 3 An exemplary powertrain control process flow according to this disclosure is shown;

[0027] Figure 4 Exemplary metrics for determining basic driver intent according to this disclosure are shown; and

[0028] Figure 5 An exemplary calibration vector according to this disclosure is shown. Detailed Implementation

[0029] The following description is exemplary in nature and is not intended to limit this disclosure, its application or use.

[0030] Referring now to the accompanying drawings, which are for illustrative purposes only and not for limiting those exemplary embodiments,... Figure 1 A vehicle 100 is schematically shown, which includes an exemplary hybrid powertrain 20 coupled to a drivetrain 60 and controlled by a control system 10. Throughout the specification, the same reference numerals denote the same elements. The powertrain 20 includes a torque generating device comprising an internal combustion engine 40 and a non-combustion torque generator 35 capable of generating and reacting torque transmitted to the drivetrain 60 via a transmission 50. One configuration of the powertrain 20 may include a torque generator 35 rotatably and mechanically coupled to a crankshaft 36 of an engine 40. The crankshaft may be rotatably and mechanically coupled to an input member 51 of a multi-ratio transmission 50 via a fluid torque coupling device (torque converter) 55. The crankshaft 36 may be mechanically and rotatably coupled to the torque generator 35 via a gearbox mechanism 38. Other configurations of the powertrain 20, including a torque generator 35 rotatably and mechanically coupled to an engine 40 mechanically coupled to a transmission 50, may be employed within the scope of this disclosure. In other embodiments, hybrid and non-hybrid powertrains may be employed, including, for example, internal combustion powertrains, electric powertrains, and hybrid powertrains of any topology (e.g., series, parallel, series / parallel, mild, full, plug-in, BAS, multi-mode, etc.).

[0031] Engine 40 is preferably a multi-cylinder internal combustion engine that converts fuel into mechanical torque through a thermodynamic combustion process. Engine 40 is equipped with multiple actuators and sensors for monitoring operation and delivering fuel to form a combustion charge, thereby generating torque in response to an operator's request for vehicle propulsion. Engine actuators include slow-speed actuators and fast-speed actuators. A fast-speed engine actuator is an actuator that performs changes in engine operation, such as changes in engine torque output in response to a command to the engine actuator during a single engine cylinder event. An example of a fast-speed engine actuator is spark ignition timing. A slow-speed engine actuator is an actuator that performs changes in engine operation, such as changes in engine torque output only after a delay exceeding a single engine cylinder event in response to a command to the engine actuator. An example of a slow-speed engine actuator is electronic throttle control (ETC). Due to delays associated with intake manifold fill time and other factors, the engine may take 100ms to 500ms to respond to changes in ETC to achieve changes in engine torque output. Engine 40 is configured to execute automatic start and stop control schemes and fuel cut-off (FCO) control schemes during ongoing operation of powertrain 20. When engine 40 is not rotating, engine 40 is considered to be in the OFF state. When engine 40 is rotating, engine 40 is considered to be in the ON state, including one or more FCO states in which engine 40 is rotating and not refueled.

[0032] The non-combustion torque machine 35 is an electrically powered torque machine 35, which includes a high-voltage multiphase motor (i.e., a motor / generator) electrically connected to the inverter module 32. The torque machine 35 includes a rotor and a stator, along with accompanying position sensors. The torque machine 35, in cooperation with the inverter module 32, is operable to convert stored electrical energy into mechanical power and vice versa. The inverter module 32 includes a fast actuator capable of completing changes in the operation of the torque machine 35 within a timeframe corresponding to a single engine cylinder event (i.e., within 10-20 milliseconds), such as changes in torque or speed output in response to a command from the engine actuator. Typically, the response time of the electrically powered torque machine 35 is many times faster than that of an internal combustion engine. An example of a fast actuator for the torque machine is a power transistor. The inverter module 32 acts as a fast actuator to control the torque machine 35. In one embodiment, electrical energy may be consumed or stored in a high-voltage battery 25.

[0033] In one embodiment, the electrically powered torque generator 35 includes an output member mechanically rotatably coupled to the crankshaft 36 of the engine 40 via a gearbox mechanism 38, which provides a mechanical power path therebetween. The gearbox mechanism 38 can be configured to transmit torque between the engine 40 and the torque generator 35, including torque transmission from the torque generator 35 to the engine 40 for automatic engine start and stop operations, traction torque assistance, torque transmission for regenerative vehicle braking, and torque transmission from the engine 40 to the torque generator 35 for high-voltage charging. In one embodiment, the gearbox mechanism 38 may include a planetary gear set. In one embodiment, the engine 40 may include a low-voltage solenoid-actuated electric starter 39 for starting the engine in response to a key-crank event.

[0034] The high-voltage battery 25 is electrically connected to the inverter module 32 via a high-voltage DC bus 29 to transmit high-voltage DC power to the torque generator 35 in response to control signals from the control system 10. The inverter module 32 is electrically connected to the torque generator 35 via a multiphase motor control power bus 31. The inverter module 32 is configured with suitable control circuitry, including power transistors, such as IGBTs, for converting high-voltage DC power to high-voltage AC power and vice versa. The inverter module 32 preferably employs pulse-width modulation (PWM) control to convert stored DC power from the high-voltage battery 25 into AC power to drive the torque generator 35 to generate torque in response to motor torque commands. Similarly, the inverter module 32 converts mechanical power delivered to the torque generator 35 into DC power in response to motor control commands (including as part of a regenerative control strategy) to generate electrical energy that can be stored in the high-voltage battery 25. The inverter module 32 is configured to control the power transistors in response to motor control commands to provide motor drive and regenerative functions. In one embodiment, the DC / DC power converter 34 is electrically connected to the low-voltage bus 28 and the low-voltage battery 27, and is also electrically connected to the high-voltage bus 29. Such electrical connections are known and will not be described in detail further. The low-voltage battery 27 is electrically connected to the auxiliary power system 45 to provide low-voltage power to low-voltage systems on the vehicle, including, for example, power windows, HVAC fans, seats, and an electric starter 39 actuated by a low-voltage solenoid.

[0035] The transmission 50 is configured to operate in one of a plurality of selectable fixed-gear operating modes at a gear ratio that achieves a preferred match between the operator's propulsion request and the engine operating point, and preferably employs one or more differential gear sets and a hydraulically actuated clutch to achieve torque transmission at a range of speed ratios between the input member 51 and the output member 62 in one of the plurality of selectable operating modes. Exemplary transmissions include, for example, automatic transmissions, dual-clutch transmissions, clutchless manual transmissions, and manual transmissions. In response to an output torque request, the transmission 50 performs upshifts to shift to an operating mode with a lower numerical multiplier (gear ratio) and downshifts to shift to an operating mode with a higher numerical multiplier. Upshifting requires a reduction in engine speed, so the engine speed matches the transmission output speed multiplied by the gear ratio associated with the target operating mode. Downshifting requires an increase in engine speed, so the engine speed matches the transmission output speed multiplied by the gear ratio associated with the target operating mode. Alternatively, the transmission 50 may be configured as a continuously variable transmission (CVT). The transmission preferably includes a first rotational position / speed sensor 52 for monitoring the rotation of the input member 51 and a second rotational position / speed sensor 54 for monitoring the rotation of the output member 62 of the transmission 50. The vehicle speed can be easily determined based on the ratio of the second rotational position / speed sensor 54 and the final drive (e.g., 65, 66). The powertrain 20 may include a torque converter 55 between the engine 40 and the transmission 50.

[0036] In one embodiment, the drivetrain 60 may include a differential gear assembly 65 mechanically coupled to a shaft 64, a transmission axle, or a half-shaft, which is mechanically coupled to a wheel 66. The drivetrain 60 transmits traction power between the transmission 50 and the road surface.

[0037] The control system 10 may include a control module 12 signal-connected to the operator interface 14. The control module 12 preferably includes multiple discrete devices co-located with the various components of the powertrain 20 to achieve operational control of the various components of the powertrain 20. The control module 12 may also include control devices that provide hierarchical control over other control devices. The control module 12 is signal-connected and operably connected, directly or via a communication bus 18, to each of the high-voltage battery 25, inverter module 32, torque generator 35, engine 40, and transmission 50 to monitor operation and determine their parameter status. The operator interface 14 of the vehicle 100 is a controller signal-connected to multiple human / machine interface devices through which the vehicle operator inputs various operator requests for propulsion or traction power and other requests for operation of the vehicle 100. The human-machine interface (HMI) device is a means of monitoring and evaluating the operator's request for traction power, including, for example, an accelerator pedal 112 providing the operator's accelerator pedal position (APP); a brake pedal 113 providing the operator's brake pedal position (BPP); a transmission range selector 114 providing a transmission range signal (PRNDL) requested by the operator; and a vehicle speed cruise control system 116 providing a vehicle speed request (CRUISE). Other HMI devices preferably include an ignition switch to enable the operator to initiate vehicle operations, including crank start and start engine 40, steering wheel, and headlight switches. The HMI devices described are exemplary and not limiting. It should also be understood that not all vehicles can include many HMI devices. For example, autonomous and semi-autonomous vehicles may have fewer or different HMI devices. The transmission range selector 114 provides a signal input indicating the direction of movement requested by the vehicle's operator, including a discrete number of operator-selectable positions indicating the preferred rotational direction of the output member 62 (forward or reverse or neutral). It should be understood that due to the vehicle's position (e.g., on a hill), the vehicle may still move in directions other than those indicated by the operator's requested movement.

[0038] The powertrain 20 includes a communication scheme, which includes a communication bus 18 to enable communication between the control system 10 and the components of the powertrain 20 in the form of sensor signals and actuator command signals. The communication scheme employs one or more communication systems and devices, including, for example, the communication bus 18, direct connection, local area network bus, serial peripheral interface bus, and wireless communication, to achieve information transmission.

[0039] Throughout the accompanying drawings, corresponding reference numerals denote the same or corresponding parts and features. As used herein, the terms control module, module, control, controller, control unit, electronic control unit, processor, and similar terms mean any one or more of the following or various combinations thereof: application-specific integrated circuit (ASIC), electronic circuitry, central processing unit (preferably microprocessor) and associated memory and storage devices (read-only memory (ROM), random access memory (RAM), electrically programmable read-only memory (EPROM), hard disk drive, etc.) or microcontroller executing one or more software or firmware programs or routines, input / output circuitry and devices (I / O) and appropriate signal conditioning and buffering circuitry, high-speed clock, analog-to-digital (A / D) and digital-to-analog (D / A) circuitry, and other components providing the described functions. A control module may include various communication interfaces, including point-to-point or discrete lines, and wired or wireless interfaces to networks, including wide area networks (WANs) and local area networks (LANs), on-board controller LANs, and factory and service-related networks. The functions of the control module as described in this disclosure can be implemented in a distributed control architecture among several networked control modules. Software, firmware, program, instruction, routine, code, algorithm, and similar terms refer to any controller-executable instruction set, including calibration, data structures, and lookup tables. A control module has a set of control routines executed to provide the described functions. These routines are executed, for example, by a central processing unit and are operable to monitor inputs from sensing devices and other network control modules, and to execute control and diagnostic routines to control actuator operation. Routines can be executed at regular intervals during ongoing engine and vehicle operation. Alternatively, routines can be executed in response to the occurrence of an event, a software call, or a request input or request via a user interface.

[0040] Figure 2 A functional block diagram of certain aspects of an exemplary control system 10 is shown. An exemplary embodiment of the control module 12 includes a drive shaft torque module 200. As described below, the drive shaft torque module 200 can determine a final drive shaft request.

[0041] The drive shaft torque module 200 may include a pedal request module 202, a conversion module 210, a torque request arbitration module 222, a torque acceleration request module (TARM) 203, and a torque shaping module 224. The pedal request module 202 determines the pedal torque request (PTR). The pedal torque request may be represented by a propulsion torque domain (i.e., torque at the crankshaft or other inputs to the drivetrain). The pedal request module 202 may determine the pedal torque request based on the accelerator pedal position APP 205 and vehicle speed information 207, as well as other suitable parameters known to those skilled in the art.

[0042] The conversion module 210 receives a pedal torque request and converts it into an axle torque domain (i.e., torque at a wheel or axle). After being converted into an axle torque domain, the request can be referred to as a driver torque request. The conversion module 210 can convert the pedal torque request based on, for example, drivetrain losses, a gear ratio selected within the transmission, one or more torque ratios, and other suitable parameters.

[0043] Arbitration module 222 can receive driver torque requests and other torque requests 225, and arbitrate between the received requests. By way of example only, arbitration module 222 can arbitrate torque requests related to longitudinal propulsion, such as driver torque requests and cruise torque requests. Arbitration module 222 outputs the winner of such arbitration. In one embodiment, arbitration between a longitudinal propulsion torque request and other torque requests not primarily for longitudinal propulsion purposes (e.g., from chassis control interventions such as stability control) can result in bypassing torque acceleration request module 203 at 223 to perform torque dispatching based on alternative control and calibration. In other embodiments, arbitration between a longitudinal propulsion torque request and other torque requests not primarily for longitudinal propulsion purposes can be performed in other modules. The output of the arbitration module is the winner of the arbitration and represents the original axle torque request (e.g., Nm), and may be referred to as the Driver Torque Target (DTT). The original axle torque request is represented using an axle torque domain (i.e., torque at the wheel or axle). As further described herein, the Driver Torque Target (DTT) can be operated by torque acceleration request module (TARM) 203.

[0044] The Torque Acceleration Request Module (TARM) 203 may receive the raw axle torque request from the driver torque target DTT from the arbitration module 222. The Torque Acceleration Request Module 203 may employ one or more calibration tables or mappings that correlate the axle torque request with torque rate limits to shape the raw axle torque request into a shaped torque request (STR), as described further in detail herein. More specifically, the calibration table may correlate a desired axle torque change with a desired axle torque change rate to achieve a vehicle acceleration response based on a desired acceleration response. It should be understood that the calibration and discussion herein are in the torque domain, and more specifically in the axle torque domain; however, vehicle performance / driving performance development may initially occur in the acceleration domain, which is later converted for applications controlled in the axle torque domain, and it should be understood that those skilled in the art understand the relationship between vehicle acceleration and axle torque. As used herein, a calibration table may refer to a calibration element, calibration array, calibration table, or a combination and library thereof. The described calibration table may be adapted to change driving style or conditions (driving modes), such as Touring, Sport, Snow, Closed Track, Four-Wheel Drive Low or High, etc. Thus, this multidimensional library of calibration tables can be defined and accessed based on the driving mode dimension. Therefore, the Torque Acceleration Request Module (TARM) 203 can include additional input at 211, such as selection via a user interface, to selectively employ a table corresponding to the selected driving mode. The Torque Acceleration Request Module (TARM) 203 can shape the torque acceleration request, for example, based on calibration table rate limits and one or more filters, to reduce or prevent the “jumping” or “rapid” sensation that may be experienced when the driver exhibits a busy or jerky accelerator pedal. Typically, torque shaping is implemented to improve driving performance and provide a pleasant, smooth, and responsive driver experience without significant limitations. The Torque Acceleration Request Module (TARM) 203 can provide a shaped torque request (STR) to the shaping module 224 for additional torque shaping, as described further in detail herein.

[0045] The forming module 224 can receive a forming torque request (STR) and provide additional torque forming. As an example only, in a powertrain capable of distributing total axle torque between different axles or to individual vehicle corners, the forming module 224 can further adjust the forming torque request (STR) for such distribution. The forming torque request STR is represented by an axle torque domain (i.e., the torque at the wheel or axle). The forming torque request STR is passed to the torque transmission module 226 and represents the currently transmitted or controlled axle torque.

[0046] Torque transmission module 226 receives a forming torque request STR from forming module 224. Torque transmission module 226 determines the final drive shaft request and may include a shaft torque arbitration module 228 for arbitrating with other shaft torque requests. Shaft torque arbitration module 228 arbitrates the forming torque request STR from forming module 224 between other shaft torque requests and shaft torque intervention 240. In one embodiment, shaft torque intervention can be adapted by keeping the execution of the forming torque request STR suspended or delayed, such that when any such intervention terminates, the forming torque request STR starts with a shaft torque corresponding to the shaft torque at the time the shaft torque intervention terminates. For example, shaft torque intervention may originate from drivetrain dynamic management (DDM), which is primarily applied for so-called vibration or shock zone management to mitigate undesirable drivetrain gear meshing disturbances (i.e., operator-perceptible noise and bumps) during torque reversal or application from a stationary state. Other shaft torque interventions may also include torque reduction requested by the traction control system when positive wheel slip is detected. Positive wheel slip can occur when the axle torque (i.e., the torque applied to the wheel) overcomes the friction between the wheel and the road surface and the wheel slips relative to the road surface in a forward direction. Other axle torque interventions may also include torque increase requests to counteract negative wheel slip, where the vehicle's tires slip or drag relative to the road surface in the opposite direction due to the negative axle torque. Other axle torque interventions may also include various brake management requests and other axle torques that affect powertrain control, such as those related to vehicle stability and tracking management, collision avoidance, initial collision mitigation and preparation, etc. These exemplary other axle torque requests and interventions are disclosed only by way of non-limiting example. Therefore, torque delivery module 226 may generally set the final drive axle request (e.g., Nm) equal to the forming torque request STR unless a higher priority other axle torque request or intervention is required. The final drive axle request is passed to actuation module 250.

[0047] Actuation module 250 receives a final drive shaft request from torque delivery module 226. Actuation module 250 determines how to fulfill the final drive shaft request. Actuation module 250 can be powertrain-specific. By way of example only, actuation module 250 can be implemented differently or use different control schemes for spark-ignition engines versus compression-ignition engines, and for electric motors in hybrid and all-electric powertrains. By way of example only, in a spark-ignition engine, actuation module 250 can change the throttle opening as a slow actuator that allows a wide range of torque control. Actuation module 250 can use a cylinder actuator module to disable a cylinder, which also provides a wide range of torque control, but may be slow and may involve driving performance and emissions issues. Actuation module 250 can use spark timing as a fast actuator. However, spark timing may not provide the same wide range of torque control. Additionally, the possible amount of torque control can vary with changes in airflow as spark timing changes (referred to as spark reserve capacity). All-electric vehicles will require an actuator module that primarily regulates motor torque via inverter control, which can rapidly and predictably change the torque. In various implementations, such as... Figure 1 In a hybrid power implementation, the actuation module 250 can employ various controls of the engine actuator and the motor actuator (e.g., the inverter) to achieve shaft torque control.

[0048] Figure 3 The Torque Acceleration Request Module (TARM) 203 is shown. Figure 2 ) and powertrain system 20 ( Figure 1 The exemplary implementation of the control of ) is a processing routine (routine) 300. The various steps shown in routine 300 can be embodied in Figure 1 The executable code is located within the control module 12. During ongoing vehicle operation, routine 300 is repeatedly executed as part of the overall powertrain system 20 control. The steps shown can be performed in the order and manner shown, or in an alternative order or simultaneously; routine 300 is exemplary. Routine 300 is entered at 301, and routine 300 includes receiving various input information required for the following operations at 303, such as accelerator pedal position application 205 and vehicle speed information 207. Figure 2The form torque request (STR) is calculated at 305, along with control parameters such as the forming torque request (STR) in this example (300). Next, the driver torque target (DTT) is calculated at 305, and the driver torque target (DTT) may include converting the pedal torque request to the shaft torque domain and arbitrating the pedal torque request and other torque requests to achieve the driver torque target (DTT). Next, the magnitude of the deviation between the driver torque target (DTT) and the forming torque request (STR) is calculated at 307. As previously mentioned, the forming torque request (STR) can be expected to suppress high rates of change according to certain time constant constraints, but its output (STR) typically converges to its input (DTT). Therefore, a deviation between the forming torque request (STR) and the driver torque target (DTT) can be expected at higher rates of change in the driver torque target (DTT), and this deviation can persist until the forming torque request (STR) and the driver torque target (DTT) converge.

[0049] At 309, the deviation is compared to a first calibration threshold K1, which represents a predetermined minimum torque change threshold sufficient to latch the historical record of the currently delivered shaft torque at or near the point of occurrence of the minimum torque change threshold. In one embodiment, the calibration threshold K1 may be element-wise. In other embodiments, the calibration threshold may be vector-wise or table-derived. The forming torque request STR represents the currently delivered shaft torque. Therefore, when the deviation exceeds the calibration threshold K1, at 311, the basic reference torque (BRT) can be latched to the value of the forming torque request STR corresponding to the time of the deviation. In other embodiments, the latched value may differ from the forming torque request, for example, by a constant offset. The basic reference torque BRT remains latched to this value as long as the deviation exceeds the calibration threshold K1. When the deviation no longer exceeds the calibration threshold K1, or as long as the deviation does not exceed the calibration threshold K1, the basic reference torque BRT tracks the forming torque request STR at 313. At 315, the basic driver intention BDI is calculated as the difference between the driver torque target DTT and the basic reference torque BRT. It should be understood that when the Basic Reference Torque (BRT) is latched, the Basic Driver Intent (BDI) maintains a measure of the operational history in the latched value of the Forming Torque Request (STR) based on the most recent deviation between the Driver Torque Target (DTT) and the Forming Torque Request (STR) exceeding a calibration threshold K1. Therefore, it should be understood that the Basic Driver Intent (BDI) provides a measure calculated relative to the time history of operation and represents the fundamental change in desired acceleration. The Basic Driver Intent (BDI) thus provides measures that include historical control information (e.g., the latched Basic Reference Torque (BRT), current control information (e.g., the Forming Torque Request (STR),) and future control information (e.g., the Driver Torque Target (DTT)).

[0050] Figure 4Two exemplary sequences for latching and releasing the basic reference torque BRT are shown; one sequence "A" concerns the accelerator pedal tip-out, and the other sequence "B" concerns the accelerator pedal tip-in. Figure 4 In the diagram, torque (TQ) is along the vertical axis, and time (t) is along the horizontal axis. The driver torque target (DTT) is represented by a solid line marked 403, the forming torque request (STR) by a dashed line marked 405, the basic reference torque (BRT) by a dashed line marked 407, and the basic driver intention (BDI) is represented by a double-ended arrow marked 409. Before time t1, the forming torque request (STR) and the basic reference torque (BRT) are closely tracking each other because the driver torque target (DTT) and the forming torque request (STR) do not deviate beyond the calibration threshold K1, even as flaring begins as indicated by a decrease in the driver torque target (DTT). At time t1, the driver torque target (DTT) and the forming torque request (STR) deviate beyond the calibration threshold K1, and the basic reference torque (BRT) is latched at the then-current forming torque request (STR). The basic reference torque (BRT) remains latched between times t1 and t2. At time t2, the driver torque target (DTT) and the forming torque request (STR) no longer deviate beyond the calibration threshold K1, and the basic reference torque (BRT) is unlocked and begins tracking the forming torque request (STR) again. After time t2, as indicated by the increase in the driver torque target DTT, moderate inversion begins. Since the driver torque target DTT and the forming torque request STR do not deviate beyond the calibration threshold K1, the forming torque request STR and the basic reference torque BRT closely track each other. At time t3, the driver torque target DTT and the forming torque request STR deviate beyond the calibration threshold K1, and the basic reference torque BRT is latched at the then-current forming torque request STR. The basic reference torque BRT remains latched between times t3 and t4. At time t4, the driver torque target DTT and the forming torque request STR no longer deviate beyond the calibration threshold K1, and the basic reference torque BRT is unlocked and begins tracking the forming torque request STR again.

[0051] It should be understood that the basic driver intention BDI can vary significantly because the driver torque target DTT remains dynamic and variable, varying according to the accelerator pedal, especially when the basic reference torque BRT remains latched and does not track the forming torque request STR to seek convergence with the driver torque target DTT. Next, at 317, the basic driver intention BDI is used to reference a second calibration threshold K2, which can be referenced from a calibration table to return a corresponding second calibration threshold K2 for any basic driver intention BDI. This second calibration threshold K2 represents a predetermined minimum torque change threshold sufficient to latch the history of the currently delivered shaft torque at or near the occurrence of the minimum torque change threshold. In one embodiment, the table referenced for the second calibration threshold K2 can be a one-dimensional vector. Other embodiments may employ a multi-dimensional calibration table or calibration library. The forming torque request STR represents the currently delivered shaft torque. Figure 5 An exemplary calibration vector is shown. It should be understood that the second calibration threshold K2 can vary as the Basic Driver Intent (BDI) changes. At 319, the deviation (i.e., the deviation between the forming torque request (STR) and the driver torque target (DTT)) is compared with the second calibration threshold K2. Therefore, when the deviation exceeds the second calibration threshold K2, at 321, the True Reference Torque (TRT) can be latched to the value of the forming torque request (STR) corresponding to the time of the deviation. In other embodiments, the latched value can be different from the forming torque request, for example, by some constant offset. The True Reference Torque (TRT) remains latched to this value as long as the deviation exceeds the second calibration threshold K2. When the deviation no longer exceeds the second calibration threshold K2, or as long as the deviation does not exceed the second calibration threshold K2, the True Reference Torque (TRT) tracks the forming torque request (STR) at 323. At 325, the True Driver Intent (TDI) is calculated as the difference between the driver torque target (DTT) and the True Reference Torque (TRT). It should be understood that when the True Reference Torque (TRT) is latched, the True Driver Intent (TDI) maintains a measure of the operational history in the latched value of the Forming Torque Request (STR) based on the most recent deviation between the Driver Torque Target (DTT) and the Forming Torque Request (STR) exceeding a second calibration threshold K2. Therefore, it should be understood that the True Driver Intent (TDI) provides a measure of the time history of operation relative to which it varies with the Basic Driver Intent (BDI) and represents the true change in required acceleration, which is related to the historical operation of time and torque that is increasingly approaching the current operation. Thus, the True Driver Intent (TDI) provides a measure that includes historical control information (e.g., the latched True Reference Torque (TRT), current control information (e.g., the Forming Torque Request (STR),) and future control information (e.g., the Driver Torque Target (DTT)).

[0052] At 327, a torque acceleration request (TAR) library is referenced to look up the torque acceleration request (TAR) value corresponding to the true driver intention (TDI). The library may include multiple, for example, one-dimensional tables, each corresponding to a specific driving mode as described above. In one embodiment, the torque acceleration request (TAR) value may represent a rate limit for axle torque change. It should be understood that, as the true driver intention (TDI) changes with the basic driver intention (BDI), this control, through a lookup based on the true driver intention (TDI), can smooth the final transition phase of acceleration change by effectively attenuating or feathering the rate of acceleration change towards the final acceleration driver torque target (DTT). The final shaping of the forming torque request (STR) at 329 can be operated to rate limit the driver torque target (DTT) during the shaping function and filtering process at 329, which may include further adaptation of the forming torque request, potentially beneficial for distributing total axle torque across multiple axles or vehicle corners. Figure 2 The torque transmission and actuation functions of modules 226 and 250 are implemented at 331 in the control of the STR power drive system based on the forming torque request. Routine 300 exits at 333, and re-enters at 301 for iterative execution, for example.

[0053] Unless explicitly described as “direct,” when describing the relationship between the first element and the second element in the above disclosure, the relationship may be a direct relationship in which there are no other intermediate elements between the first element and the second element, or it may be an indirect relationship in which there are one or more intermediate elements (spatial or functional) between the first element and the second element.

[0054] It should be understood that one or more steps in the method may be performed in different orders (or simultaneously) without altering the principles of the invention. Furthermore, while each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of this disclosure may be implemented in and / or combined with features of any other embodiment, even if such combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and substitutions of one or more embodiments for each other remain within the scope of this disclosure.

Claims

1. A method for controlling a powertrain, comprising: Compare the torque request from the operator with the powertrain torque control signal; When the deviation between the torque request and the torque control signal is greater than a predetermined amount, the basic reference torque is latched to a first predetermined value; as well as The shaft torque is controlled based on the difference between the requested torque and the basic reference torque. Controlling the powertrain torque based on the difference between the requested torque and the basic reference torque includes: A threshold is established based on the difference between the torque request and the basic reference torque; When the deviation between the torque request and the torque control signal exceeds the threshold, the actual reference torque is latched to a second predetermined value; and The shaft torque is controlled based on the difference between the requested torque and the actual reference torque.

2. The method according to claim 1, wherein, Controlling the shaft torque based on the difference between the torque request and the actual reference torque includes: using the difference between the torque request and the actual reference torque to reference a calibration library that correlates torque variation with the rate of torque variation.

3. The method according to claim 2, wherein, The calibration library is defined by driving modes.

4. The method according to claim 1, further comprising: When the deviation between the torque request and the torque control signal is not greater than the predetermined amount, the basic reference torque is tracked to the shaft torque.

5. The method according to claim 1, further comprising: When the deviation between the torque request and the torque control signal is not greater than the threshold, the real reference torque is tracked to the shaft torque.

6. The method according to claim 1, further comprising: During shaft torque intervention, control of the powertrain torque is delayed based on the difference between the torque request and the actual reference torque. as well as After the shaft torque intervention, the powertrain torque is controlled based on the difference between the torque request and the actual reference torque, using an initial shaft torque corresponding to the final shaft torque at the time of intervention completion.

7. The method according to claim 1, wherein, The first predetermined value includes the shaft torque value that exists when the initial deviation between the torque request and the torque control signal is greater than the predetermined amount.

8. The method according to claim 1, wherein, The second predetermined value includes the shaft torque value that exists when the initial deviation between the torque request and the torque control signal is greater than the threshold.

Images