Control system for vehicle powertrain

Abstract

Aspects of the present disclosure relate to a control scheme for controlling a vehicle in which an upshift of the vehicle is anticipated and upshift preparation has begun. A torque modulation scheme for modulating torque from the power source during the upshift is applied according to the source of torque demand.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a control system for a vehicle powertrain. In particular, but not exclusively, the present disclosure relates to control of a powertrain during upshifts of a vehicle. Aspects of the invention relate to control systems, vehicles and methods. BACKGROUND

[0002] It is known to provide a control system for a vehicle which processes driver inputs to determine the torque that should be generated by a power source of the vehicle. However, existing systems can not accurately anticipate future driver demand - leading to a slow reaction of the vehicle to driver demand and an unsatisfactory driving experience. In particular, during upshifts of a gearbox, poor management of vehicle torque can result in a slow reaction of the vehicle to changing driver demand or a reduction in vehicle acceleration.

[0003] Furthermore, existing systems can attempt to manage torque during an upshift by increasing engine torque before the upshift occurs to maintain the torque at the wheels at a relatively constant level. However, in the event that an upshift is cancelled after upshift preparation has begun (for example due to a change in driver demand), existing systems can react slowly, resulting in an undesirable acceleration of the vehicle.

[0004] The upshift process can also vary depending on the way in which the vehicle is controlled. For example, when a vehicle is controlled by a driver with minimal driver assistance, it can be desirable to maintain acceleration through an upshift, or more generally, for the vehicle to react quickly to inputs from the driver. However, when using an advanced driver assistance system (ADAS) such as adaptive cruise control, it can be desirable to reduce the impact of an upshift such that the vehicle behaviour is not significantly impacted by the upshift causing a reduction in the smoothness of the vehicle motion.

[0005] It is an object of the present invention to address one or more of the drawbacks associated with the prior art. SUMMARY

[0006] Aspects and embodiments of the invention provide a control system, vehicle and method as claimed in the appended claims.

[0007] According to an aspect of the application, there is provided a control system for controlling a powertrain of a vehicle, the powertrain comprising a power source and a driveline arranged to receive torque from the power source, the driveline comprising a transmission and a torque converter, the control system comprising one or more processors collectively configured to: receive a shift signal indicative of an intended upshift of the transmission, the shift signal comprising an indication of a torque ratio of the transmission after the intended upshift of the transmission; receive a driver torque demand signal, the driver torque demand signal comprising a driver torque demand; receive a torque converter slip value signal, the torque converter slip value signal comprising a torque converter slip value; receive a predicted input shaft speed signal, the predicted input shaft speed signal comprising a predicted input shaft speed of the transmission after the intended upshift of the transmission; determine a normalised torque demand from the driver torque demand, the torque converter slip value and the predicted input shaft speed; determine a predicted torque demand from the normalised torque demand and the torque ratio of the transmission after the upshift; and output a first output signal, the first output signal requesting the power source to generate torque in accordance with the predicted torque demand.

[0008] In this way, the torque demand after the upshift can be more accurately predicted. This can enable a smoother upshift by anticipating the torque required to maintain a constant rate of acceleration of the vehicle or a constant torque at the wheels, as can be required depending on the driving conditions.

[0009] The torque demand can be a driver torque demand, for example an input of an accelerator pedal, and the predicted torque demand can be a predicted driver torque demand.

[0010] The processors can be collectively configured to receive a road gradient signal indicative of a road gradient and to determine the normalised torque demand from the road gradient. By taking into account changes in road gradient, the torque demand can be more accurately predicted, thereby providing a smoother driving experience in a wider range of circumstances.

[0011] The processors can be collectively configured to receive a vehicle speed signal indicative of a vehicle speed and to determine the normalised torque demand from the vehicle speed. By taking into account the vehicle speed, the predicted driver torque demand can be further improved and made more accurate. For example, the vehicle speed can affect air resistance and rolling resistance, thereby changing the behaviour of the vehicle.

[0012] The processor can be collectively configured to receive a power source torque maximum capability signal indicative of a power source torque maximum capability and determine the predicted torque demand as a function of the powertrain torque maximum capability. The power source maximum torque can be used to calculate the predicted torque demand to ensure that the powertrain is driven at a torque within its capabilities, thereby avoiding damage to the powertrain. Furthermore, the powertrain torque can vary based on operating conditions and, therefore, by providing a variable value as opposed to a hard coded value, the likelihood of damaging the powertrain can be further reduced.

[0013] The power source can comprise an internal combustion engine and an electric machine and the processor can be collectively configured to output a first output signal to cause the internal combustion engine to produce torque according to the predicted driver torque demand prior to an anticipated upshift of the transmission. In this way, torque can be increased prior to the upshift, thereby reducing acceleration lag due to a possible decrease in torque at the wheels during the upshift.

[0014] The processor can be collectively configured to output a second signal to cause the electric machine to produce electric machine torque according to the predicted driver torque prior to the anticipated upshift of the transmission, the electric machine torque of the electric machine being opposite to the torque produced by the internal combustion engine. This enables the internal combustion engine to increase torque while not causing undesirable acceleration prior to the upshift. The electric machine torque can be decreased quickly and reliably during the upshift, such that the torque on the wheels can remain substantially constant.

[0015] According to a further aspect of the application, there is provided a vehicle comprising a control system of the above-mentioned aspect.

[0016] According to a further aspect of the application, there is provided a method for controlling a powertrain of a vehicle, the powertrain comprising a power source and a driveline arranged to receive torque from the power source, the driveline comprising a transmission and a torque converter, the method comprising: receiving a shift input signal indicative of an upshift of the transmission, the shift input signal comprising an indication of a torque ratio of the transmission after the upshift; receiving a first input signal, the first input signal comprising a torque demand; receiving a second input signal, the second input signal comprising a torque converter slip value; receiving a third input signal, the third input signal comprising a predicted input shaft speed of the transmission after the upshift; determining a normalised torque demand based at least in part on the torque demand, the torque converter slip value and the predicted input shaft speed; determining a predicted torque demand based at least in part on the normalised torque demand and a predicted torque ratio of the transmission after the upshift; and outputting a first output signal indicative of the predicted torque demand, the first output signal arranged to cause the power source to produce torque.

[0017] According to a still further aspect of the application, there are provided computer readable instructions arranged, when executed by a computer, to perform the method of the still further aspect of the application.

[0018] According to a further aspect of the application there is provided a control system for controlling a powertrain of a vehicle, the powertrain comprising a power source and a driveline arranged to receive torque from the power source, the driveline comprising a transmission, the control system comprising one or more processors collectively configured to: receive a shift signal indicative of an intended upshift of the transmission; receive a predicted torque demand signal, the predicted torque demand signal containing information indicative of a predicted post-shift torque demand; receive a current torque demand signal, the current torque demand signal containing information indicative of a current torque demand; compare the predicted post-shift torque demand and the current torque demand; and output a first output signal, the first output signal arranged to cause a change in torque generated by the power source in dependence on the comparison.

[0019] In this way, the control system can output a torque modulation value which is based on the required change in torque relative to the current torque. By outputting a difference rather than an absolute torque value, this output can be more easily manipulated by downstream processes.

[0020] The predicted torque demand signal can be the first output signal of the first mentioned aspect of the application. Thus, the predicted post-shift torque demand can be determined in accordance with the method of the further aspect of the application. Other optional aspects of the first mentioned aspect of the application can also be incorporated into the further aspect of the application.

[0021] The processors can be collectively configured to apply a modulation factor to the determined difference to calculate a modulated determined difference, and the first output signal can be output in dependence on the modulated determined difference. In this way, the determined difference can be varied based on factors such as the source of the torque demand or the driving mode, such that the change in torque during the shift can be modified as required.

[0022] The processors can be collectively configured to: receive a torque demand signal indicative of a torque demand; determine a filtered torque demand based on the torque demand signal; and determine a modulation factor based on a comparison of the torque demand signal and the filtered torque demand. Optionally, the torque demand can be a driver torque demand, for example a driver torque demand from an accelerator pedal. The filtered torque can be determined based on a low pass filter. In this case, the deviation between the torque demand (i.e. the raw, unfiltered torque demand) and the filtered torque demand can be indicative of a change in behaviour of the system or the driver. This change in behaviour can warrant a reduction in deceleration or acceleration. In this case, the torque modulation can be altered accordingly, such that the vehicle can quickly comply with the demand of the driver during the upshift. While the determination of the high frequency component of the demand can be determined by a high pass filter and without the comparison step, the low pass filtering step can be used to provide an input to the power source to determine the drive to be generated by the engine, and thus the introduction of the comparison step can reduce the overall computational demand.

[0023] The modulation factor can be between 0 and 1. With values in this range, the modulation factor can for example cancel the torque increase for upshift when the upshift can be cancelled due to a decrease in torque demand, or can keep the torque increase in case the torque demand is similar to the predicted torque demand.

[0024] Applying the modulation factor to the determined difference can comprise multiplying the determined difference by the modulation factor. This can provide an efficient means of applying the modulation factor with low computational demand.

[0025] The torque demand signal can contain information indicative of at least one of: an accelerator pedal input; a road gradient; a vehicle speed; and a driving mode, and the one or more processors can be collectively configured to determine the predicted post-upshift torque demand based on any of: the accelerator pedal input; the road gradient; the vehicle speed; and / or the driving mode. By taking into account factors such as the accelerator pedal input, the road gradient, the vehicle speed and the driving mode, the control system can modify the torque produced by the power source to suit particular driving conditions and driver demands. As a result, the driving experience can be smoother for the user of the vehicle.

[0026] According to a further aspect of the application, there is provided a vehicle comprising a control system according to the further aspect described above.

[0027] According to a further aspect of the application, there is provided a method for controlling a powertrain of a vehicle, the powertrain comprising a power source and a driveline arranged to receive torque from the power source, the driveline comprising a transmission, the method comprising: receiving a shift signal indicative of an upshift of the transmission; receiving a predicted torque demand signal, the predicted torque demand signal containing information indicative of a predicted post-upshift torque demand; receiving a current torque demand signal, the current torque demand signal containing information indicative of a current torque demand; determining a difference between the predicted post-upshift torque demand and the current torque demand from the predicted torque demand and the current torque demand; and outputting a first output signal based on the determined difference and the shift signal, the first output signal arranged to cause a change in torque produced by the power source.

[0028] According to a further aspect of the application, there are provided computer readable instructions arranged, when executed by a computer, to perform a method according to the aspects described above.

[0029] According to an additional aspect of the application, there is provided a control system for controlling a power source of a vehicle, the control system comprising one or more processors commonly configured to: receive a torque demand signal, the torque demand signal comprising a torque demand; receive a torque demand source signal, the torque demand source signal (or torque demand signal) comprising an indication of a source of the torque demand; select a torque modulation scheme for modulating torque from the power source during a shift up in dependence on the source of the torque demand for modulating torque from the power source during a shift up; and output a first output signal, the first output signal arranged to cause the power source to vary torque output in accordance with the selected torque modulation scheme.

[0030] In this way, the torque modulation can be varied in dependence on the source of the torque demand. For example, if the torque demand is received from an advanced driver assistance system (ADAS) (e.g. cruise control), it can be desirable to maintain a substantially constant torque at the output of the driveline so that the vehicle moves more smoothly. However, if the source of the torque is a driver input (e.g. an accelerator pedal), it can be desirable to make the vehicle more responsive, for example by making the vehicle more responsive to changes in road gradient.

[0031] The processors can be commonly configured to receive a shift signal indicative of an anticipated shift up of the gearbox, and to select the torque modulation scheme in response to receiving the shift signal. The torque modulation scheme can be for managing torque from the power source during a shift up of the gearbox.

[0032] The processors can be commonly configured to determine a torque modulation based on the torque demand using the selected torque modulation scheme, and the first output signal can be arranged to cause the power source to vary torque output in accordance with the determined torque modulation.

[0033] The processors can be commonly configured to: select a first torque modulation scheme to maintain a constant torque output from the powertrain during a shift up when the source of the torque demand is an advanced driver assistance system (ADAS) or an autonomous driving system. In this way, the perception of a shift up by a driver can be reduced when an advanced driver assistance system is in use. As a result, the driver can have an improved driving experience.

[0034] The shift signal can comprise an indication of a torque ratio of the gearbox after the shift up, and the first torque modulation scheme can comprise determining a product of the torque demand and the torque ratio of the gearbox before the shift up, and determining a required torque based on dividing the determined product of the torque demand and the torque ratio by the torque ratio of the gearbox after the shift up. In this way, the torque at the wheels of the vehicle can be maintained substantially constant while maintaining low computational demand.

[0035] The processors can be collectively configured to select a second torque modulation scheme to predict the driver torque demand after the upshift when the source of the torque demand is driver input. This second torque modulation scheme can include the methods described in connection with the first described aspect of the application to predict the driver torque demand. The system's reaction can be different due to the input from the driver being different than the advanced driver assistance system. For example, when the driver is providing input of the torque demand, the torque can be determined based on the drive mode or road grade so that the vehicle responds to the driver's demand.

[0036] The torque demand signal can contain information indicative of at least one of: accelerator pedal input; road grade; vehicle speed; and drive mode, and the processors can be collectively configured to predict the driver torque demand after the upshift from the first input signal. By taking into account factors such as accelerator pedal input, road grade, vehicle speed, and drive mode, the control system can modify the torque produced by the power source to suit the particular driving conditions and driver demand. Thus, the driving experience can be smoother for the user of the vehicle.

[0037] According to other additional aspects of the application, there is provided a vehicle comprising a control system of the additional aspects.

[0038] According to yet another additional aspect of the application, there is provided a method for controlling a power source of a vehicle, the method comprising: receiving a shift signal indicative of an upshift of a transmission; receiving a torque demand signal, the torque demand signal (or first input signal) comprising a torque demand; receiving a torque demand source signal (or second input signal), the torque demand source signal comprising an indication of a source of the torque demand; in response to receiving the shift signal, selecting a torque modulation scheme based on the source of the torque demand for use in modulating the torque from the power source during the upshift; and outputting a first output signal, the first output signal causing the power source to vary the torque output in accordance with the selected torque modulation scheme.

[0039] According to one or more aspects of the application, there are provided computer readable instructions arranged, when executed by a computer, to perform the method according to the above yet another additional aspect.

[0040] The above control system can comprise one or more controllers collectively comprising at least one electronic processor having electrical inputs for receiving input signals; and at least one memory device electrically coupled to the at least one electronic processor and having instructions stored therein; and wherein the at least one electronic processor is configured to access the at least one memory device and execute the instructions on the at least one memory device to perform the defined method.

[0041] It will be understood that a method described separately can be executed by a common control system, and a control system described separately can actually be a combined common control system. Furthermore, when a signal is described as being received by a control system, that signal can be generated within the control system, for example, through an internal process, and can be received by a part of the control system (e.g., a downstream process).

[0042] Within the scope of this application, it is expressly intended that various aspects, embodiments, examples, and alternatives set forth in the preceding paragraphs, in the claims, and / or in the following description and drawings, and in particular their respective features, may be adopted independently or in any combination. That is, all embodiments and / or features of any embodiment may be combined in any manner and / or combination, unless such features are incompatible. The applicant reserves the right to amend any initially filed claim or accordingly file any new claim, including the right to modify any initially filed claim to be subordinate to any other claim and / or incorporated into any other claim, even if not initially claimed in that manner. Attached Figure Description

[0043] One or more embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which:

[0044] Figure 1 A vehicle according to an embodiment of the present invention is shown;

[0045] Figure 2 A schematic diagram of the control system and powertrain of a vehicle according to an embodiment of the present invention is shown;

[0046] Figure 3 A flowchart illustrating a method according to an embodiment of the present invention is shown;

[0047] Figure 4 A flowchart illustrating a method according to an embodiment of the present invention is shown;

[0048] Figure 5a , Figure 5b and Figure 5c A diagram illustrating the changes in the powertrain during upshifting is shown;

[0049] Figure 6 A flowchart illustrating a method according to an embodiment of the present invention is shown;

[0050] Figure 7 A flowchart illustrating a method according to an embodiment of the present invention is shown; and

[0051] Figure 8 A flowchart illustrating a method according to an embodiment of the present invention is shown. Detailed Implementation

[0052] Embodiments of the present invention relate to a control system for determining the torque required during a vehicle upshift. Upshifting occurs when the transmission is actuated to change the gear driven by the vehicle's power source, such that a "higher" gear is selected and the vehicle's drivetrain receives a lower gear ratio. Typically, if the torque does not change during an upshift, the torque at the vehicle's wheels will decrease. When the vehicle is accelerating, this will make the driver perceive a decrease in vehicle acceleration.

[0053] Figure 1 Vehicles according to all embodiments of the present invention are shown to provide background for the invention.

[0054] Vehicle 10 includes a control system 100 and a powertrain 111. The control system 100 is configured to control the powertrain 111. Vehicle 10 can be a hybrid electric vehicle with an electric motor and an internal combustion engine. Vehicle 10 can be a mild hybrid electric vehicle (MHEV). An MHEV is characterized by not having the ability to charge its battery using mains power, and the battery can only be charged via the internal combustion engine and regenerative braking. Alternatively, the sole primary energy source for an MHEV can be liquid fuels such as gasoline and diesel, and the MHEV may not have an electrical connection for charging the battery from an external source. The battery capacity of an MHEV can be less than 2 kWh. The battery voltage of an MHEV can be approximately 48 volts or lower.

[0055] Alternatively, vehicle 10 may be a plug-in hybrid electric vehicle (PHEV). A PHEV may be characterized by being configured to receive electrical energy from an external source, such as via a connection to mains power. Therefore, a PHEV may include an external electrical connection for charging the battery.

[0056] Figure 2 A schematic diagram of the control system 100 and power system 111 of vehicle 10 is shown.

[0057] Control system 100 is configured to control the powertrain 111 of the vehicle. The term powertrain is intended to cover a system that includes one or more power sources and a transmission coupled to one or more power sources. Powertrain 111 includes an internal combustion engine 110, an electric motor 120, and a battery 130. In this example, battery 130 is configured to supply electrical energy 137 to and receive electrical energy 137 from electric motor 120. Internal combustion engine 110 and electric motor 120 may be collectively referred to as a single power source or as dual power sources. Both internal combustion engine 110 and electric motor 120 transmit torques 117, 127 to transmission 140 in powertrain 111. Transmission 140 includes a gearbox and may include additional components such as a torque splitter, torque converter, differential, and wheels of vehicle 10. The additional components may be parts of transmission 140 other than the gearbox, or the gearbox may be detachable from transmission 140.

[0058] It should be understood that this represents only one possible vehicle architecture according to an embodiment of the invention, and other vehicle architectures (e.g., architectures with separate electric motors and generators) are within the scope of the invention.

[0059] like Figure 2 The control system 100 shown includes a controller, although it should be understood that this is merely illustrative and any number of controllers may be included. The control system 100 includes one or more processors configured collectively to control the powertrain of a vehicle, as described below. The controller includes a processing unit and a memory unit. The processing unit may be one or more electronic processing devices operably executing computer-readable instructions. The memory unit may be one or more memory devices. The memory unit is electrically coupled to the processing unit. The memory unit is configured to store instructions, and the processing unit is configured to access the memory unit and execute the instructions stored on the memory unit.

[0060] like Figure 2 As shown, the control system 100 can provide signals 115, 125 to the internal combustion engine 110 and / or the electric motor 120 to transmit a certain amount of torque. For example, the control system 100 can output signals to the powertrain control module (PCM). In the case of the internal combustion engine 110, signal 115 can be sent to the PCM to advance or delay the ignition timing or increase or decrease the flow rate of the fuel / air mixture entering the engine 110. Signals can be output by publishing on an onboard network (e.g., CAN or FlexRay bus), and signals can be received or input by reading the published information.

[0061] Battery 130 can supply electrical energy 137 to motor 120 to generate torque, and can supply electrical energy 139 to electric vehicle components (such as heaters, fans, displays, etc.). Battery can provide control system 100 with information related to the power 139 supplied to other electrical devices 150.

[0062] The control system 100 may receive information 135 from the battery 130. Examples include one or more of the following: battery state of charge; battery temperature; and an indication of battery health status. Generally, the information 135 received from the battery may indicate to the control system 100 the battery's discharge capacity, which is the rate at which the battery can supply energy to the motor 120 and other electrical devices 150 of the vehicle 10. In some examples, the battery 130 or its battery controller may directly output the battery discharge capacity to the control system 100. The battery 130 or its battery controller may output information 135 to the control system 100 indicating the amount of power supplied to the electrical devices 150.

[0063] The control system 100 includes input devices and output devices. The input devices may include electrical inputs of the control system 100 adapted to read signals from an on-board network. The output devices may include electrical outputs of the controller 100 adapted to publish signals on the on-board network. The output devices may be arranged to output signals 115 for controlling the engine 110 (e.g., by increasing or decreasing the torque output by the engine). The output devices may be arranged to output signals 125 for controlling the electric motor 120 (e.g., by increasing or decreasing the torque output by the electric motor).

[0064] The control system 100 is arranged to receive torque demand data 102 from a torque demand input device 101 (e.g., an accelerator pedal). The control system 100 can then determine, at least in part, the desired torque to be generated by the engine 110 and the electric motor 120 based on the received torque demand data 102. The control system 110 can then output control signals 115, 125 to control the engine 110 and the electric motor 120 to generate the desired torque. The torque demand data 102 may be referred to as the torque demand, or, in an implementation where the vehicle is manually controlled by the driver, as the driver torque demand. The torque demand data may be the current torque demand. A first input signal may include the torque demand data 102. The current torque demand signal may contain information indicating the current torque demand.

[0065] The control system 100 is configured to receive a driving mode signal 104 from a driving mode selector 103, which may be in the form of a driving mode selector switch or other input from a touchscreen or the vehicle's human-machine interface. The driver can select a driving mode based on desired vehicle behavior. For example, a "Sport" mode can be selected when a quick response and high acceleration are desired, while a "Comfort" mode can be selected when a less responsive driving mode is desired. The control system 100 can determine the required torque based at least in part on the driving mode signal 104.

[0066] The control system 100 is arranged to receive a vehicle condition signal 106 from a vehicle condition sensor 105. The vehicle condition sensor 105 can determine attributes such as road gradient and / or vehicle speed, and the vehicle condition signal 106 can include this information. The control system 100 can receive the vehicle condition signal 106 and can determine the required torque based at least in part on the information in the vehicle condition signal (e.g., road gradient and / or vehicle speed). Those skilled in the art will understand that the vehicle condition information signal can include any parameters that directly or indirectly affect the engine's torque requirements.

[0067] The control system is configured to receive transmission data 108 from a transmission management system 107. The transmission management system 107 may be referred to as a transmission control system or transmission management system. The transmission control system 107 can provide the transmission data 108, and the transmission data 108 may include information such as: the target gear after upshifting, a shift signal indicating an impending upshift, a torque converter slip value indicating the slip level of the torque converter from the transmission 140, and a predicted transmission input shaft speed after upshifting. A first input signal may include the driver's torque demand. The torque converter slip value signal may include the torque converter slip value. The predicted input shaft speed signal may include the predicted input shaft speed of the transmission after the expected upshift. In some examples, these values ​​may be normalized values.

[0068] The control system 100 may have one or more internally stored values, such as the gear ratios of different gears, the maximum torque capacity of the powertrain, the mixing ratio for changing the torque output of the transmission system 140, and a loss value indicating torque loss in the powertrain. The maximum torque capacity of the powertrain may be referred to as the maximum torque capacity of the power source and may be in the form of a maximum torque capacity signal of the power source.

[0069] The control system 100 can determine the predicted driver torque for the target gear based on any or all of the data mentioned above, and thus can more effectively determine the predicted torque required for the target gear. Furthermore, the data included in the individual signals 102, 104, 106, and 108 can be combined by the signal management system and received by the control system 100 as a single signal.

[0070] The term "control system" can be used to describe a specific control module or a system of sensors and modules. For example, the drivetrain control module 107, torque demand input device 101, driving mode selection device 103, and vehicle condition sensor 105 can be considered to be within the same control system as control system 100. When a control system is described as being arranged to receive signals, it should be understood that one part or program of control system 100 can receive signals from other parts or programs of the control system, and it is not necessary for signals to be sent from external devices to a physically separate control system.

[0071] Figure 3 This is a flowchart illustrating a method 200 for determining the torque required during upshifting.

[0072] Within method 200, at step 210, the control system receives a shift signal, for example, from the transmission control module. This shift signal may include an indication of the torque ratio of the current gear and / or the torque ratio of the target gear the system is shifting into (referred to as the upshift torque ratio). The shift signal may indicate the expected upshift of the transmission.

[0073] In step 220, the required torque at the target gear is determined, also known as the torque demand after upshifting. The torque demand after upshifting can be based on signals received by the control system (as referred above). Figure 2 The torque demand can be determined from any signal described herein. Specifically, at step 220, the normalized torque demand can be determined based on the driver's torque demand, the torque converter slip value, and the predicted input shaft speed. The torque demand after upshifting can be included in a signal (e.g., a predicted torque demand signal). The predicted torque demand signal can contain information indicating the predicted torque demand after upshifting.

[0074] At step 230, the normalized torque demand can be processed using the transmission torque ratio after upshifting to the target gear (also known as the upshift torque ratio). Therefore, at step 230, the predicted upshift torque demand can be determined. See below for further details. Figure 4 The determination of torque demand after upshifting is further described. The driver's torque demand can be predicted based on the normalized torque demand and the shift signal.

[0075] At step 240, the control system may output a first output signal to cause the power source to generate torque based on the predicted torque demand of the driver.

[0076] In this way, the torque generated by the engine and / or electric motor can be better suited to the driver's needs, thereby improving the driving experience.

[0077] Figure 4 A further flowchart is shown illustrating how data received by the control system can be processed to determine the predicted driver torque after upshifting. A first processing step 310 may receive inputs from various sources. Specifically, processing 310 may receive one or more of the following: accelerator pedal input 301, previous driver or terrain mode 302, current driver or terrain mode 303, road gradient 304, vehicle speed 305, high or low range requirement 307, target gear ratio excluding torque converter slip 308, and predicted transmission input shaft speed at the target gear 309. For example, inputs 301 to 309 may be in the form of signals, such as road gradient signals, vehicle speed signals, or high or low range requirement signals. Based on inputs 301 to 309, processing 310 generates a normalized torque demand 315. Processing 310 may include an algorithm for calculating the normalized torque demand 315 based on inputs 310 to 309, the algorithm being selected based on desired vehicle characteristics. The second processing step 320 calculates the predicted torque demand at the target gear based on the normalized torque demand 315. The second processing step 330 calculates the predicted torque demand at the target gear based on the known losses within the powertrain 321, the gear ratio at the target gear 322, and the maximum torque capacity of the powertrain 323.

[0078] By following process 300, a more accurate prediction of torque demand at the target gear can be determined.

[0079] Figure 5a The graph shows the torque ratio 350 of the transmission versus time during an upshift. The control system receives a shift signal at the first time point T1, indicating a possible upshift. At this point, the vehicle's total torque remains constant, and the gear ratio 350 remains unchanged. However, the control system enters the preparation phase PP.

[0080] like Figure 5b As shown, during the preparation phase, engine torque increases by 360°. This increase may help to cope with the gear ratio change that will occur during the subsequent ratio phase (RP). Furthermore, as... Figure 5c As shown, during the preparation phase, the motor torque 370 can be reduced. This reduction in motor torque 370 is equivalent to the increase in engine torque 360, ensuring that the total torque remains unaffected.

[0081] Once the engine torque has increased sufficiently to 360... The control system can then leave the preparation stage (PP) and enter the speed ratio stage (RP). This leads to an increase in torque. It can be called torque modulation because it can be applied to the base torque demand to change the base torque demand value. Torque variation. The value is designed to match the increased torque required during upshifts due to the decrease in torque ratio during the subsequent speed ratio phase RP.

[0082] During the gear ratio phase RP, the transmission's torque ratio 350 changes from the torque ratio in first gear to the torque ratio in second gear. The torque ratio can change gradually over time because the clutch may be engaged in second gear when it is disengaged from first gear. Therefore, the transmission can have an effective torque ratio between the torque ratios of first and second gears during the gear ratio phase RP.

[0083] During the speed ratio phase RP, the engine torque 360 ​​can remain constant, while the motor torque 370 can increase. The increase in motor torque 370 and the decrease in torque ratio 350 can be managed so that the product of motor torque 370 and torque ratio 350 remains essentially constant. At the end of the speed ratio phase, motor torque 370 can return to the same value as before the preparation phase PP.

[0084] The total torque, calculated as the sum of engine torque 360 ​​and motor torque 370, can be managed so that the product of the total torque and torque ratio 350 before the preparation phase PP is the same as the product of the total torque and torque ratio 350 after the speed ratio phase RP.

[0085] Figure 6 A flowchart 400 for determining torque modulation is shown. At step 410, the control system receives a shift input signal from the transmission management system indicating that a shift is imminent. However, it should be understood that the control system can determine that a shift is about to occur and can command the transmission management system 107 to perform the shift. In this case, the shift signal can be an internal signal, such as a signal published on a CAN bus, and can be received in this manner.

[0086] In step 420, the predicted torque demand after upshifting is determined. This can be done based on the above. Figure 2 This determination is made by the method described in Figure 5, or alternatively by, for example, multiplying the current required torque by the torque ratio in the target gear and dividing the value by the torque ratio in the current gear.

[0087] At step 430, the difference between the current torque demand and the predicted torque demand after upshifting is determined. This value can be referred to as torque modulation.

[0088] At step 440, a determination is made regarding whether upshifting is possible. If upshifting may be cancelled, a first torque modulation arbitration value can be output, and if the shift may proceed as expected, a second torque modulation arbitration value can be output. If the shift may be completely cancelled and the vehicle should proceed in the initial gear, the first torque modulation arbitration value can be 0. If the shift proceeds completely as expected, a torque modulation arbitration value of 1 can be output. Based on any intermediate determinations, a value between 0 and 1 can be output. The torque modulation arbitration value can be considered as the proportion of the torque modulation value that should be passed to the downstream control logic.

[0089] The decision to cancel an upshift can be made by the control system or the drivetrain management system, where signals are sent from the system's decision-making component to other parts of the system. The control system can anticipate the drivetrain management system's decision to cancel an upshift by comparing filtered and unfiltered torque demands.

[0090] A determination on whether to cancel an upshift can be made based on a comparison between the unfiltered and filtered torque demand, or a comparison between the predicted and actual torque demand. A difference between the actual or unfiltered torque demand and the predicted or filtered torque demand exceeding a threshold can indicate that acceleration should be stopped, and optionally, the shift can be canceled. In cases where acceleration should be stopped, a torque modulation arbitration value of 0 can be output.

[0091] At step 450, the final torque modulation value can be determined based on the torque modulation value determined at step 430 and the torque modulation arbitration value determined at step 440. The determination of the final torque modulation value at step 450 can be performed by multiplying the torque modulation value by the torque modulation arbitration value.

[0092] At step 460, the final torque value can be determined and output. In some embodiments, the final torque value is output as a first output signal. The final torque value can be a final torque modulation value, which can be set to change the torque generated by the power source, or the final torque modulation value can be added to the current torque value to provide the torque requirement. At step 460, a first output signal can be output, which can be set to cause a change in the torque generated by the power source based on the difference between the determined predicted upshift torque requirement and the current torque requirement, as well as the shift signal.

[0093] It should be understood that processing steps 450 and 440 can vary, and the torque modulation value can be arbitrated by any method, but providing the torque modulation value simplifies the processing at step 450.

[0094] Figure 7 A flowchart illustrating a method 500 for selecting a torque modulation scheme is shown. At step 510, a shift signal indicating a possible upshift in the vehicle's transmission is received.

[0095] At step 520, the source of the vehicle's torque demand is determined. The torque demand may originate from the driver, for example via the accelerator pedal, or via an advanced driver assistance system (ADAS) (such as cruise control or adaptive cruise control). Alternatively, the source of the torque demand may originate from a fully autonomous driving program or system. This determination may be based on a signal received from the torque demand input device 101 (torque source signal), or it may be determined within the control system, as the control system may continuously communicate with the advanced driver assistance system or the autonomous driving program, or the control system may include an advanced driver assistance system or the autonomous driving program. The determined source of the vehicle's torque demand may be output as a torque source signal.

[0096] At step 530, a torque modulation scheme can be selected based on the source of the torque demand. If the source of the torque demand is driver input, the method can proceed to step 540, and the predicted torque demand at the target gear can be determined by a first torque modulation scheme. The first torque modulation scheme may include a combination of... Figure 3 and Figure 4 The method described is for predicting the driver's torque demand after upshifting.

[0097] If the source of the torque demand determined at step 530 is the advanced driver assistance system, a second torque modulation scheme can be used at step 550. The second torque modulation scheme can be configured to maintain substantially constant torque at the vehicle wheels during upshifts by altering the overall vehicle torque, such that the product of the torque generated by the power source and the transmission ratio remains substantially constant throughout the shift. Specifically, torque modulation scheme 550 can determine the torque from the power source such that the product of the power source torque and torque ratio before upshifting is the same as the product of the power source torque and torque ratio after upshifting.

[0098] At step 560, a combination can be used, for example. Figure 6 The described torque modulation arbitration scheme further processes the torque modulation, or the torque modulation can be output to the power source to generate the necessary torque. The torque modulation can be output as a first output signal. This first output signal can be configured to cause the power source to change its torque output according to the selected torque modulation scheme.

[0099] Figure 8 A further flowchart of method 600 is shown, by which a torque modulation value can be determined. Signal 601 is a torque demand source signal indicating the source of the torque demand. At step 610, a torque modulation scheme is determined based on the source of the torque demand. If the torque demand is a driver torque demand input using a driver torque input device (e.g., accelerator pedal), a first torque modulation scheme 620 will be used.

[0100] To use the first torque modulation scheme 620, the predicted driver demand at the target gear can be determined, which can also be referred to as the predicted torque demand after upshifting. The predicted torque demand after upshifting 621 can be referred to as previously... Figure 3 and Figure 4 As stated above, the torque modulation value 625 can be determined using the current driver demand 623, which may include subtracting the predicted upshift torque demand from the current torque demand to produce the torque modulation value 625.

[0101] Alternatively, if the advanced driver assistance system (ADAS) is the source of the torque demand, a second torque modulation scheme 630 can be used. The second torque modulation scheme 630 may have inputs: a primary torque request 631 from the ADAS and a post-upshift gear ratio 633. To maintain a substantially constant torque at the wheels throughout the upshift, the torque modulation can be calculated by multiplying the primary torque request 631 by the current gear ratio 633, dividing that value by the post-upshift gear ratio, and then subtracting the primary torque request 631. This produces a second torque modulation value 625.

[0102] The torque modulation value 625 can be received by the torque modulation arbitration process 650 and arbitrated using the torque modulation arbitration value 645.

[0103] At processing point 640, the torque modulation arbitration value 645 can be determined based on the predicted torque demand 641 and the current torque demand 643. Alternatively, the filtered torque demand 641 and the original, unfiltered torque demand 643 can be used for torque modulation arbitration calculation 640. For example, if the filtered torque demand 641, which is based on the original torque demand and processed using a low-pass filter, is significantly different from the original, unfiltered torque demand 643, this can indicate a need for reduced acceleration, thus requiring the cancellation of upshifts, and therefore the torque modulation arbitration value 645 can be set to 0.

[0104] The torque modulation value 655 can therefore be output as the output of the torque modulation process 600.

[0105] It should be understood that various changes and modifications can be made to this invention without departing from the scope of this application.

Claims

1. A control system for controlling a powertrain of a vehicle, the powertrain including a power source and a transmission arranged to receive torque from the power source, the transmission including a gearbox, the control system including one or more processors, the one or more processors being configured to: Receive a shift signal indicating a desired upshift in the transmission; Receive torque demand signal, wherein the torque demand signal includes torque demand; Receive a torque source signal, the torque source signal including an indication of the source of the torque demand in the torque demand signal; In response to receiving the shift signal, a torque modulation scheme is selected based on the source of the torque demand for modulating the torque from the power source during the upshift; and A first output signal is output, which is configured to cause the power source to change its torque output according to the selected torque modulation scheme.

2. The control system according to claim 1, wherein, The processors are collectively configured to determine torque modulation based on the torque demand using a selected torque modulation scheme, wherein the first output signal is configured to cause the power source to change the torque output according to the determined torque modulation.

3. The control system according to claim 1 or 2, wherein, The processors are collectively configured to select a first torque modulation scheme when the source of the torque demand is an advanced driver assistance system or an autonomous driving system, in order to maintain a constant torque output from the powertrain during the upshift.

4. The control system according to claim 3, wherein, The shift signal includes an indication of the torque ratio of the transmission after the upshift, and wherein the first torque modulation scheme includes: Determine the product of the torque requirement and the torque ratio of the transmission before the upshift, and The required torque is determined by dividing the product of the determined torque requirement and the torque ratio by the upshift torque ratio of the transmission.

5. The control system according to claim 1, 2, 3 or 4, wherein, The processors are collectively configured to select a second torque modulation scheme to predict the driver's torque demand after the upshift when the source of the torque demand is driver input.

6. The control system according to claim 5, wherein, The first input signal contains information indicating at least one of the following: Accelerator pedal input; Road slope; Vehicle speed; and Driving modes, and The processors are collectively configured to predict the driver's torque demand after the upshift based on the first input signal.

7. A vehicle comprising the control system according to claims 1 to 6.

8. A method for controlling a drive system of a vehicle, the drive system including a power source and a transmission arranged to receive torque from the power source, the transmission including a gearbox, the method comprising: Receive a shift signal instructing the transmission to upshift; Receive a first input signal, the first input signal including torque demand; Receive a second input signal, the second input signal including an indication of the source of the torque demand included in the first signal; In response to receiving the shift signal, a torque modulation scheme is selected based on the source of the torque demand for modulating the torque from the power source during the upshift; as well as The first output signal is output, which causes the power source to change the torque output according to the selected torque modulation scheme.

9. A computer-readable instruction, which, when executed by a computer, is configured to perform the method according to claim 8.

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