Method and system for regenerative braking for hybrid vehicles

Abstract

Methods (400, 500) for power transmission, comprising: Setting a clutch torque (612, 712) of a clutch (191) of a differential (193) that drives a first wheel (131) and a second wheel (131), in response to a difference between a braking torque of the second wheel (131) and a braking torque of the first wheel (131); and Setting a regenerative torque of an electric machine (120) in response to the braking torque of the first wheel (131) and the braking torque of the second wheel (131) and the clutch torque (612, 712).

Description

AREA

[0001] This description generally concerns methods and systems for controlling the power transmission of a hybrid vehicle. These methods and systems can be particularly useful for hybrid vehicles equipped with a limited-slip electronic differential. STATE OF THE ART / BRIEF OVERVIEW

[0002] DE 11 2009 005 233 T5 discloses a drive control system for a standby four-wheel drive vehicle. DE 102 20 355 A1 discloses a conical friction clutch. US 2008 / 0 162 009 A1 discloses a wheel steering device. DE 10 2011 013 338 A1 discloses a method for operating a vehicle braking system.

[0003] A hybrid vehicle can utilize regenerative braking and friction braking to slow down. During regenerative braking, an electric motor is used to decelerate the vehicle and convert its kinetic energy into electrical energy. Friction braking can be used when the regenerative braking capability of the hybrid vehicle is insufficient to bring it to a complete stop. However, using friction braking can waste the vehicle's kinetic energy, as it is converted into heat rather than electrical energy. Therefore, it may be preferable to activate and utilize regenerative braking whenever it is desirable to bring the vehicle to a stop.However, there may sometimes be few opportunities for a hybrid vehicle to use regenerative braking. Even when regenerative braking is possible, driving conditions may further restrict its use to minimize the possibility of wheel slip. Therefore, it may be desirable to develop methods and systems that enhance a hybrid vehicle's ability to decelerate and recharge its batteries through regenerative braking.

[0004] The inventors of the present invention recognized the aforementioned problems and developed a power transmission method comprising: adjusting the clutch torque of a differential clutch in response to a difference between the braking torque of a second wheel and the limiting torque of a first wheel; and adjusting the regenerative torque of an electric machine in response to the braking torque of the first wheel, the braking torque of the second wheel, and the clutch torque. The differential drives the first and second wheels.

[0005] Furthermore, the inventors have developed a system comprising: a motor; a dual-clutch transmission coupled to the motor via a drive shaft; a rear-wheel drive unit comprising an electrically controlled limited-slip differential and an electrically controlled differential clutch, which adjusts the torque transmission to a half-shaft on which a first wheel is located and a second half-shaft on which a second wheel is located, the rear-wheel drive unit being coupled to the dual-clutch transmission; an electric machine directly coupled to the rear-wheel drive unit; and a control unit containing executable instructions stored in non-volatile memory for adjusting a limited-slip differential torque in response to a requested regenerative torque from the electric machine and a braking torque from the first wheel.

[0006] By adjusting the torque of an electrically controlled differential and the regenerative torque of an electric machine, it may be possible to increase the efficiency of converting a vehicle's kinetic energy into electrical energy, even when there are few opportunities to utilize regenerative braking. In particular, the torque of the electrically controlled differential can be adjusted while a vehicle is cornering, maximizing the torque transfer from the vehicle's wheels to an electric machine without causing wheel lock-up. Furthermore, in examples where the torque of the clutch in a differential is controlled via an axle, the regenerative torque of the electric machine can be adjusted in response to the torque of the clutch in the differential.

[0007] The present description can offer several advantages. In particular, the approach can improve the efficiency of converting the vehicle's kinetic energy into electrical energy. Furthermore, the approach can improve driving dynamics. Additionally, the approach can provide advantages when a vehicle is cornering and when a vehicle is operating on a road surface that has different coefficients of friction for the first and second drive wheels. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1A is a schematic representation of the power transmission of a hybrid vehicle; Fig. 1B is a sketch of a motor for the power transmission of a hybrid vehicle; Fig. Figure 2 is a schematic representation of the power transmission of a hybrid vehicle, including controls for various power transmission components; Fig. Figure 3 is a schematic representation of a dual-clutch transmission located in the power transmission of a hybrid vehicle; Fig. Figure 4 is a flowchart of a first method for operating a power transmission of a hybrid vehicle; and Fig. Figure 5 is a flowchart of a second method for operating a power transmission of a hybrid vehicle; Fig. 6 is a prophetic sequence of regenerative braking according to the procedure of Fig. 4; and Fig. 7 is a prophetic sequence of regenerative braking according to the procedure of Fig. 5. DETAILED DESCRIPTION

[0008] The following description concerns systems and procedures for operating a power transmission of a hybrid vehicle. Fig. Figure 1A-3 shows an exemplary hybrid vehicle system that includes a power transmission with an electric motor, an integrated starter / generator, a dual-clutch transmission and a rear-wheel drive unit with an electric machine positioned behind the dual-clutch transmission. Fig. Figure 4 shows a first method for operating an electric machine of a power transmission with an electrically controlled differential with limited slip. Fig. Figure 5 shows a second method for controlling an electrically controlled limited-slip differential of an electric machine. Prophetic sequences of regenerative braking according to the method of Fig. 4 and Fig. 5 will be in the Fig. 6 and Fig. 7 shown.

[0009] Fig. Figure 1A represents an exemplary vehicle propulsion system 100 for a vehicle 121. The vehicle propulsion system 100 includes at least two power sources, namely an internal combustion engine 110 and an electric machine 120. The electric machine 120 can be configured to use or consume a different energy source than the engine 110. For example, the engine 110 can consume a liquid fuel (e.g., gasoline) to generate engine power, while the electric machine 120 can consume electrical energy to generate power for the electric machine. Accordingly, a vehicle with the propulsion system 100 can be described as a hybrid electric vehicle (HEV). In the description of Fig. 1A Mechanical connections between different components are represented as solid lines, while electrical connections between different components are represented as dashed lines.

[0010] The vehicle drive system 100 has a front axle (not shown) and a rear axle 122. In some examples, the rear axle may comprise two half-shafts, for example, a first half-shaft 122a and a second half-shaft 122b. The vehicle drive system 100 also has front wheels 130 and rear wheels 131. The rear axle 122 is coupled to the electric machine 120 and the transmission 125 via a drive shaft 129. The rear axle 122 can be driven either purely electrically and exclusively via the electric machine 120 (e.g., purely electric drive or drive mode, in which the motor does not burn air or fuel and does not rotate), in a hybrid manner via the electric machine 120 and the engine 110 (e.g., parallel mode), or exclusively via the engine 110 (e.g., purely engine-driven drive mode) in a purely internal combustion engine-driven manner.A rear drive unit 136 can transmit power from the motor 110 or the electric machine 120 to the axle 122, causing the drive wheels 131 to rotate. The rear drive unit 136 can include a first gear set, the differential 193, and an electrically controlled differential clutch 191, which regulates the torque transmission to axles 122a and 122b. In some examples, the electrically controlled differential clutch 191 can communicate a torque value via the CAN bus 299. The torque transmission to axles 122a and 122b can be the same when the electrically controlled differential clutch is open. The torque transmission to axle 122a can differ from the torque transmitted to axle 122b when the electrically controlled differential clutch 191 is partially closed (e.g.,with slippage, so that the speed input to the clutch differs from the speed output of the clutch) or is closed. The rear drive unit 136 can also include one or more clutches (not shown) to decouple the gearbox 125 and the electric motor 120 from the wheels 131. The rear drive unit 136 can be directly coupled to the electric motor 120 and the axle 122.

[0011] In the representation of Fig. 1A is a transmission 125 connected between the motor 110 and the electric motor 120, which is assigned to the rear axle 122. In one example, the transmission 125 is a dual-clutch transmission (DCT). In this example, where the transmission 125 is a DCT, the DCT may have a first clutch 126, a second clutch 127, and a gearbox 128. The DCT 125 delivers torque to a drive shaft 129 to supply torque to the wheels 131. As described below with respect to Fig. As discussed in more detail in section 2, the transmission can shift 125 gears by selectively opening and closing the first clutch 126 and the second clutch 127.

[0012] The electric machine 120 can receive electrical power from an onboard electrical energy storage device 132. Furthermore, the electric machine 120 can provide a generator function to convert engine power or the vehicle's kinetic energy into electrical energy, which can be stored in the energy storage device 132 for later use by the electric machine 120 or an integrated starter / generator 142. A first inverter system controller (ISC1) 134 can convert alternating current generated by the electric machine 120 into direct current for storage in the energy storage device 132, and vice versa.

[0013] In some examples, the energy storage device 132 may be configured to store electrical energy that can be supplied to other electrical consumers located on board the vehicle (not the electric motor), including cabin heating and air conditioning, engine starting, headlights, cabin audio and video systems, etc. As a non-limiting example, the energy storage device 132 may include one or more batteries and / or capacitors.

[0014] A control system 14 can communicate with one or more of the motor 110, the electric machine 120, the energy storage device 132, the integrated starter / generator 142, the transmission 125, etc. The control system 14 can receive sensory feedback information from one or more of the motor 110, the electric machine 120, the energy storage device 132, the integrated starter / generator 142, the transmission 125, etc. Furthermore, in response to this sensory feedback, the control system 14 can send control signals to one or more of the motor 110, the electric machine 120, the energy storage device 132, the transmission 125, etc. The control system 14 can receive an output request from the vehicle propulsion system from a human driver 102 or an autonomous control system.For example, the control system 14 can receive sensory feedback from the pedal position sensor 194, which communicates with the pedal 192. The pedal 192 can schematically refer to an accelerator pedal. Similarly, the control system 14 can receive a signal from a human driver 102 or an autonomous control system indicating a vehicle braking request from the driver. For example, the control system 14 can receive sensory feedback from a pedal position sensor 157, which communicates with a brake pedal 156.

[0015] The energy storage device 132 can periodically absorb electrical energy from a power source 180 (e.g., a stationary power grid) located outside the vehicle (e.g., not part of the vehicle), as indicated by an arrow 184. As a non-restrictive example, the vehicle drive system 100 can be configured as a plug-in hybrid electric vehicle (HEV), in which electrical energy can be supplied to the energy storage device 132 from the power source 180 via an electrical energy transmission cable 182. During recharging of the energy storage device 132 from the power source 180, the electrical transmission cable 182 can electrically couple the energy storage device 132 and the power source 180. In some examples, the power source 180 can be connected to an inlet port 150.Furthermore, in some examples, a charge status indicator 151 can indicate a charge status of the energy storage device 132.

[0016] In some examples, electrical energy can be drawn from the power source 180 by a charger 152. For instance, the charger 152 can convert alternating current from the power source 180 into direct current (DC) for storage in the energy storage device 132. Furthermore, a DC-DC converter 153 can convert the DC voltage from the charger 152 from one voltage to another. In other words, the DC-DC converter 153 can function as a type of electrical power converter.

[0017] While the vehicle drive system is operating to propel the vehicle, the electrical transmission cable 182 between the power source 180 and the energy storage device 132 can be disconnected. The control system 14 can detect and / or control the amount of electrical energy stored in the energy storage device, which can be referred to as the state of charge (SOC).

[0018] In other examples, the electrical transmission cable 182 can be omitted, and electrical energy can be wirelessly received from the power source 180 at the energy storage device 132. For example, the energy storage device 132 can receive electrical energy from the power source 180 via one or more methods of electromagnetic induction, radio waves, and electromagnetic resonance. It is therefore understood that any suitable approach for recharging the storage device 132 with electrical energy from a power source that is not part of the vehicle can be used. In this way, the electric machine 120 can power the vehicle using an energy source other than the fuel used by the engine 110.

[0019] The electrical energy storage device 132 includes a controller for the electrical energy storage device 139 and a power distribution module 138. The controller for the electrical energy storage device 139 can provide charge balancing between an energy storage element (e.g., battery cells) and communication with other vehicle controllers (e.g., a controller 12). The power distribution module 138 controls the power flow into and out of the electrical energy storage device 132.

[0020] The vehicle propulsion system 100 may also include an ambient temperature / humidity sensor 198 and sensors dedicated to the vehicle's occupancy status, for example, onboard cameras 105, seat load cells 107, and door detection technology 108. The vehicle system 100 may also include inertial sensors 199. The inertial sensors 199 may include one or more of the following: longitudinal acceleration, lateral acceleration, upward acceleration, yaw rate, roll angle, and pitch angle sensors (e.g., accelerometers). Yaw, pitch, roll, lateral acceleration, and longitudinal acceleration axes are as specified. As an example, the inertial sensors 199 may be coupled to the vehicle's restraint control module (RCM) (not shown), the RCM comprising a subsystem of the control system 14.The control system can adjust the engine power and / or the wheel brakes to increase vehicle stability in response to the sensor(s) 199. In another example, the control system can adjust an active suspension system 111 in response to an input from the inertial sensors 199. The active suspension system 111 can include an active suspension system comprising hydraulic, electrical, and / or mechanical devices, as well as active suspension systems in which the vehicle height is controlled based on individual corners (e.g., independently controlled vehicle heights for four corners), based on each axle (e.g., vehicle height for the front and rear axles), or a single vehicle height for the entire vehicle. Data from the inertial sensor 199 can also be communicated to the controller 12, or alternatively, the sensors 199 can be electrically coupled to the controller 12.The normal load or force applied to the drive wheels 131 can be determined using load sensors 188.

[0021] One or more tire pressure monitoring sensors (TPMS) can be coupled to one or more tires on the vehicle's wheels. For example, shows Fig. 1A a tire pressure sensor 197, which is coupled to a wheel 131 and configured to monitor the pressure in a tire of wheel 131. Although this is not explicitly shown, it is understood that each of the in Fig. The four tires specified in 1A may have one or more tire pressure sensors 197. Furthermore, in some examples, the vehicle drive system 100 may include a pneumatic control unit 123. The pneumatic control unit can receive information regarding the tire pressure from the tire pressure sensor(s) 197 and send the tire pressure information to the control system 14. Based on the tire pressure information, the control system 14 can issue a command to the pneumatic control unit 123 to inflate or deflate one of the vehicle wheels. Although not explicitly shown, it is understood that the pneumatic control unit 123 can be used to inflate or deflate tires of any of the tires specified in 1A. Fig. The four wheels shown in Figure 1A are assigned to the control system. For example, in response to a signal indicating reduced tire pressure, the control system 14 can issue a command to the pneumatic control unit 123 to inflate one or more tires. Alternatively, in response to a signal indicating increased tire pressure, the control system 14 can issue a command to the pneumatic control unit 123 to deflate one or more tires. In both examples, the pneumatic control unit 123 can be used to inflate or deflate tires to an optimal tire pressure rating, which can extend tire life.

[0022] One or more wheel speed sensors (WWS) 195 can be coupled to one or more wheels of the vehicle drive system 100. The wheel speed sensors can detect the rotational speed of each wheel. Such an example of a WWS can include a permanent magnet sensor.

[0023] The vehicle drive system 100 may also include an accelerometer 20. The vehicle drive system 100 may also include an inclinometer 21.

[0024] The vehicle drive system 100 can further include a starter 140. The starter 140 can comprise an electric motor, a hydraulic motor, etc., and is used to turn the engine 110 in order to initiate the operation of the engine 110 under its own power.

[0025] The vehicle powertrain system 100 may also include a brake system control module (BSCM) 141. In some examples, the BSCM 141 may include an anti-lock braking system, so that wheels (e.g., 130, 131) remain in contact with the road surface during braking, according to driver inputs, thus preventing the wheels from locking and causing skidding. In some examples, the BSCM may receive input from the wheel speed sensors 195.

[0026] The vehicle propulsion system 100 may further include a belt-integrated starter / generator (BISG) 142. The BISG can generate electrical power when the engine 110 is running, and the generated electrical power can be used to power electrical devices and / or charge the on-board storage device 132. As shown in Fig. As specified, a second inverter system controller (ISC2) 143 can receive alternating current from the BISG 142 and convert the alternating current generated by the BISG 142 into direct current for storage in the energy storage device 132. The integrated starter / generator 142 can also provide torque to the motor 110 during motor start-up or under other conditions to supplement the motor torque.

[0027] In some examples, the vehicle propulsion system 100 may include one or more electric machines 135a and 135b for driving the vehicle 121 or for providing regenerative braking via the front wheels 130. The third converter (ISC3) 147a can convert alternating current generated by the electric machine 135a into direct current for storage in the electrical energy storage device 132 or provide alternating current to the electric machine 135a for driving the vehicle 121. Likewise, the fourth converter (ISC4) 147a can convert alternating current generated by the electric machine 135b into direct current for storage in the electrical energy storage device 132 or provide alternating current to the electric machine 135b for driving the vehicle 121. The electric machines 135a and 135b may be collectively referred to as the front wheel electric machines.Alternatively, a single electric motor of the front wheels can drive both front wheels 130 and / or provide regenerative braking for this via an axle which may have an electronic limited-slip differential, as shown in 136, 191 and 193.

[0028] The vehicle drive system 100 can also include a power distribution box (PDB) 144. The PDB 144 can be used to route electrical power through various circuits and auxiliary units in the vehicle's electrical system.

[0029] The vehicle propulsion system 100 may further include a high current fuse box (HCFB) 145 and comprise a variety of fuses (not shown) used to protect the wiring and electrical components of the vehicle propulsion system 100.

[0030] The vehicle propulsion system 100 may further include an electric motor electronics coolant pump (MECP) 146. The MECP 146 can be used to circulate coolant to dissipate heat generated by at least the electric machine 120 of the vehicle propulsion system 100 and the electronics system. The MECP can draw electrical power, for example, from the onboard energy storage device 132.

[0031] The controller 12 can comprise part of a control system 14. In some examples, the controller 12 can be a single control unit of the vehicle. As shown, the control system 14 receives information from a variety of sensors 16 (various examples of which are described here) and sends control signals to a variety of actuators 81 (various examples of which are described here). For example, the sensors 16 can include: tire pressure sensor(s) 197, wheel speed sensor(s) 195, an ambient temperature / humidity sensor 198, on-board cameras 105, seat load cells 107, door detection technology 108, inertial sensors 199, etc. In some examples, the motor 110, the transmission 125, the electric motor 120, etc., can be included.Assigned sensors communicate information regarding the various states of the motor, transmission and electric motor operation to the control unit 12, as in relation to . Fig. 1B, Fig. 2 and Fig. 3 will be discussed in more detail.

[0032] The vehicle drive system 100 can further include a heating device with a positive temperature coefficient (PTC) 148. For example, the PTC heating device 148 can comprise a ceramic material, such that the ceramic material can absorb a large amount of current when its resistance is low, which can lead to rapid heating of the ceramic element. However, as the element heats up and reaches a threshold temperature, the resistance can become very high and therefore may no longer generate much heat. Thus, the PTC heating device 148 can be self-regulating and exhibit a high degree of overheating protection.

[0033] The vehicle drive system 100 may also include an air conditioning compressor module 149 for controlling an electric air conditioning compressor (not shown).

[0034] The vehicle propulsion system 100 may further include a Vehicle Audible Sounder for Pedestrians (VASP) 154. For example, the VASP 154 may be configured to generate audible tones via a sounder 155. In some examples, audible tones may be activated by the VASP 154, communicating with the sounders 155, in response to a driver triggering the sound, or automatically in response to the engine speed falling below a threshold, or upon detection of a pedestrian.

[0035] The vehicle propulsion system 100 can also include an onboard navigation system 17 (e.g., a global positioning system) on a dashboard 19, with which a driver can interact. The navigation system 17 can include one or more location sensors to assist in estimating the vehicle's location (e.g., geographic coordinates). For example, an onboard navigation system 17 can receive signals from GPS satellites (not shown) and determine the vehicle's geographic location from the signal. In some examples, the geographic location coordinates can be communicated to the controller 12.

[0036] The instrument panel 19 may also include a display system 18 configured to show information to the driver. As a non-limiting example, the display system 18 may include a touchscreen or a human-machine interface (HMI), a display that allows the driver to view geographic information and input commands. In some examples, the display system 18 may be wirelessly connected to the internet (not shown) via a controller (e.g., 12). Thus, in some examples, the driver may communicate with a website or software application (app) via the display system 18.

[0037] The instrument panel 19 may also include an operator interface 15 through which the driver can adjust the vehicle's operating state. In particular, the operator interface 15 may be configured to initiate and / or terminate operation of the vehicle's power transmission (e.g., the engine 110, the BISG 142, the DCT 125, and the electric machine 120) based on operator input. Various examples of the operator ignition interface 15 may include interfaces requiring a physical device, such as an active key that can be inserted into the operator ignition interface 15 to start the engine 110 and turn on the vehicle, or removed to turn off the engine 110 and turn off the vehicle. Other examples may include a passive key that is communicatively coupled to the operator ignition interface 15.The passive key can be configured as an electronic key fob or smart key that does not need to be inserted into or removed from the ignition interface 15 to operate the vehicle's engine 110. Instead, it may be necessary for the passive key to be in or near the vehicle (e.g., within a threshold distance). In other examples, a start / stop button can be used additionally or optionally, which is manually pressed by the driver to start or stop the engine 110 and to turn the vehicle on or off. In other examples, a remote start of the engine can be initiated via a remote computing device (not shown), for example, a mobile phone or a smartphone-based system, where a user's mobile phone sends data to a server, and the server communicates with the vehicle's control unit 12 to start the engine.

[0038] With reference to Fig. Figure 1B shows a detailed view of an internal combustion engine 110, which comprises a multitude of cylinders, one of which is in Fig. The engine 110 is controlled by an electronic engine control unit 111B. The engine 110 includes a combustion chamber 30B and cylinder walls 32B with a piston 36B located therein and connected to a crankshaft 40B. According to the illustration, the combustion chamber 30B communicates with an intake manifold 44B and an exhaust manifold 48B via a corresponding intake valve 52B and exhaust valve 54B. Each intake and exhaust valve can be operated by an intake cam 51B and an exhaust cam 53B. The position of the intake cam 51B can be determined by an intake cam sensor 55B. The position of the exhaust cam 53B can be determined by an exhaust cam sensor 57B. The intake cam 51B and the exhaust cam 53B can be moved relative to the crankshaft 40B. The intake valves can be deactivated and kept in a closed state via an intake valve deactivation mechanism 59B.The exhaust valves can be deactivated and kept in a closed state via an exhaust valve deactivation mechanism 58B.

[0039] According to the illustration, a fuel injection device 66B is positioned such that it injects fuel directly into cylinder 30B, a process known to those skilled in the art as direct injection. Alternatively, fuel can be injected into an intake port, a process known to those skilled in the art as one-nozzle-per-intake injection. The fuel injection device 66B delivers liquid fuel proportionally to the pulse width of the signal from the engine control unit 111B. The fuel is supplied to the fuel injection device 66B by a fuel system 175B, which includes a tank and a pump. Furthermore, according to the illustration, the intake manifold 44B communicates with an optional electronic throttle 62B (e.g., a butterfly valve), which sets the position of a throttle valve 64B to control the airflow from the air filter 43B and the air intake 42B to the intake manifold 44B.The throttle 62B regulates the airflow from an air filter 43B in the engine air intake 42B to the intake manifold 44B. In some examples, the throttle 62B and the throttle valve 64B can be arranged between the intake valve 52B and the intake manifold 44B in such a way that the throttle 62B is an intake port throttle.

[0040] A distributorless ignition system 88B provides a spark to the combustion chamber 30B via a spark plug 92B in response to the engine control unit 111B. According to the diagram, a wideband lambda (Universal Exhaust Gas Oxygen - UEGO) sensor 126B is coupled to the exhaust manifold 48B, which is located upstream of a catalytic converter 70B in the direction of exhaust gas flow. Alternatively, the UEGO sensor 126B can be replaced by a binary lambda sensor.

[0041] The catalyst 70B can, in one example, contain multiple catalyst modules. In another example, multiple emission control devices, each containing multiple modules, can be used. The catalyst 70B can, in one example, be a three-way catalyst.

[0042] The 111B motor control unit is in Fig. Figure 1B shows a conventional microcomputer, comprising: a microprocessor unit 102B, input / output ports 104B, read-only memory 106B (e.g., non-volatile memory), random-access memory 108B, keep-alive memory 110B, and a conventional data bus. Other controllers mentioned here may have a similar processor and memory configuration.According to the diagram, in addition to the signals already discussed, the engine control unit 111B receives signals from sensors connected to the engine 110, including: engine coolant temperature (ECT) from temperature sensor 112B, which is connected to a cooling sleeve 114B; manifold pressure (MAP) from pressure sensor 122B, which is connected to the intake manifold 44B; engine position from a Hall sensor 118B, which detects the position of the crankshaft 40B; mass of air entering the engine from sensor 120B; and throttle position from sensor 58B. Atmospheric pressure can also be detected for processing by the engine control unit 111B (sensor not shown).In a preferred aspect of the present description, the motor position sensor 118B generates a predetermined number of evenly spaced pulses at each revolution of the crankshaft, from which the motor speed (RPM) can be determined. The motor controller 111B can receive input from a human-machine interface 115B (e.g., push button or display of a touch-sensitive screen).

[0043] During operation, each cylinder in the 110 engine is typically subjected to a four-stroke cycle: the cycle includes the intake stroke, the compression stroke, the power stroke, and the exhaust stroke. During the intake stroke, the exhaust valve 54B generally closes and the intake valve 52B opens. Air is drawn into the combustion chamber 30B via the intake manifold 44B, and the piston 36B moves toward the bottom of the cylinder to increase the volume in the combustion chamber 30B. The position at which the piston 36B is near the bottom of the cylinder and at the end of its stroke (e.g., when the combustion chamber 30B has reached its maximum volume) is commonly referred to by those skilled in the art as bottom dead center (BDC). During the compression stroke, the intake valve 52B and the exhaust valve 54B are closed. The piston 36B moves toward the cylinder head to compress the air within the combustion chamber 30B.The point at which the piston 36B is closest to the cylinder head at the end of its stroke (e.g., when the combustion chamber 30B has its smallest volume) is commonly referred to by those skilled in the art as top dead center (TDC). In a process subsequently referred to as injection, fuel is introduced into the combustion chamber. In a process subsequently referred to as ignition, the injected fuel is ignited by known ignition means, such as the spark plug 92B, resulting in combustion. During the power stroke, the expanding gases push the piston 36B back to bottom dead center (BDC). The crankshaft 40B converts piston movements into torque of the rotating shaft. Finally, during the exhaust stroke, the exhaust valve 54B opens to discharge the burnt air-fuel mixture to the exhaust manifold 48B, and the piston returns to TDC.It should be noted that the above is merely an example and that the timing of the opening and / or closing of the intake and exhaust valves may vary, for example to provide positive or negative valve overlap, late closing of the intake valve, or various other examples.

[0044] Fig. Figure 2 is a block diagram of vehicle 121, which includes a powertrain or transmission 200. The powertrain consists of Fig. 2 includes the one in Fig. Engine 110 shown in 1A-B. Other common components from Fig. 2 and Fig. 1A are identified by the same reference numerals and are discussed in detail below. According to the diagram, the powertrain 200 includes the vehicle system control 12, the motor control 111B, the electric machine control 252, the transmission control 254, the energy storage device control 253, and the brake control 141 (also referred to here as the brake system control module). The control units can communicate via the Controller Area Network (CAN) 299. Each of the control units can provide information to other control units, such as torque output limits (e.g., the maximum torque output of the controlled device or component), torque input limits (e.g., the maximum torque input of the controlled device or component), torque output of the controlled device, sensor and actuator data, and diagnostic information (e.g.,Information regarding a malfunctioning transmission, engine, electric machine, and brakes. Furthermore, the vehicle system control can provide commands to the engine control (111B), electric machine control (252), transmission control (254), and brake control (141) to respond to driver input requests and other requirements based on vehicle operating conditions.

[0045] For example, in response to a driver releasing the accelerator pedal and the vehicle speed decreasing, the vehicle control unit 12 can request a desired wheel torque or wheel power level to provide a desired degree of vehicle deceleration. The desired wheel torque can be provided by the vehicle control unit 12, which requests a first braking torque from the electric machine control unit 252 and a second braking torque from the brake control unit 141, with the first and second torques providing the desired braking torque at the vehicle wheels 131.

[0046] In other examples, the control of powertrain devices may be divided differently than in Fig. Figure 2 illustrates this. For example, a single controller can take the place of the vehicle system controller 12, the engine controller 111B, the electric machine controller 252, the transmission controller 254, and the brake controller 141. Alternatively, the vehicle system controller 12 and the engine controller 111B can form a single unit, whereas the electric machine controller 252, the transmission controller 254, and the brake controller 141 can be independent controllers.

[0047] In this example, the drive train 200 can be powered by the engine 110 and the electric machine 120. In other examples, the engine 110 can be omitted. The engine 110 can be started with an engine starter (e.g., 140), with a belt-integrated starter / generator (BISG) 142, or with an electric machine 120. In some examples, the BISG 142 can be coupled directly to the engine crankshaft at either end (e.g., front or rear). The electric machine 120 (e.g., a high-voltage electric machine, operating at more than 30 volts) is also referred to here as an electric machine, drive motor, and / or generator. Furthermore, the torque of the engine 110 can be adjusted via a torque actuator 204, such as a fuel injection device, a throttle, etc.

[0048] The BISG 142 is mechanically coupled to the motor 110 via a belt 231. The BISG 142 can be coupled to a crankshaft (not shown) or a camshaft (not shown). The BISG 142 can be operated as an electric motor when it is supplied with electrical energy via the electrical energy storage device 132, which is also referred to herein as the onboard energy storage device 132. The BISG 142 can additionally be operated as a generator, which supplies the electrical energy storage device 132 with electrical energy.

[0049] The power transmission 200 includes the engine 110, which is mechanically coupled to the dual-clutch transmission (DCT) 125 via the crankshaft 40B. The DCT 125 includes a first clutch 126, a second clutch 127, and a gearbox 128. The DCT 125 outputs torque to the shaft 129 to transmit torque to the vehicle wheels 131. The transmission control unit 254 selectively opens and closes the first clutch 126 and the second clutch 127 to shift the DCT 125.

[0050] The gearbox 128 can contain a variety of gears. One clutch, for example the first clutch 126, can control odd-numbered gears 261 (e.g., first, third, fifth gears, and reverse gear), while another clutch, for example the second clutch 127, can control even-numbered gears 262 (e.g., second, fourth, and sixth gears). By using such an arrangement, gears can be changed without interrupting the power flow from the engine 110 to the dual-clutch transmission 125.

[0051] The electric machine 120 can be operated to provide torque to the drivetrain 200 or to convert the drivetrain's torque into electrical energy, which is to be stored in the electrical energy storage device 132 in a regeneration mode. Furthermore, the electric machine 120 can convert the vehicle's kinetic energy into electrical energy for storage in the electrical energy storage device 132. The electric machine 120 communicates electrically with the energy storage device 132. The electric machine 120 has a higher output torque capacity than the starter (e.g., 140) which is located in Fig. 1A is shown, or the BISG 142. Furthermore, the electric machine 120 directly drives the drive train 200 or is directly driven by the drive train 200.

[0052] The electrical energy storage device 132 (e.g., a high-voltage battery or power source) can be a battery, a capacitor, or an inductor. The electric machine 120 is driven via a gear set in the rear drive unit 136 (in Fig. (1A shown) mechanically coupled to the wheels 131 and the dual-clutch transmission. The electric machine 120 can, by operating as an electric motor or generator, as commanded by the control unit of the electric machine 252, provide positive or negative torque to the drive train 200.

[0053] Furthermore, a frictional force can be applied to the wheels 131 by actuating the friction wheel brakes 218. For example, the friction wheel brakes 218 can be engaged in response to the driver pressing a brake pedal (e.g., 192) with their foot and / or in response to instructions from the brake control unit 141. The brake control unit 141 can also actuate the brakes 218 in response to information and / or requests from the vehicle system control unit 12. Likewise, a frictional force on the wheels 131 can be reduced by releasing the wheel brakes 218 in response to the driver releasing their foot from a brake pedal, as well as in response to instructions from the brake control unit and / or instructions and / or information from the vehicle system control unit. For example, the vehicle brakes can exert a frictional force on the wheels 131 via the control unit 141 as part of an automated engine stop procedure.

[0054] The vehicle system control 12 can also communicate vehicle suspension settings to the suspension control 280. The suspension (e.g., 111) of the vehicle 121 can be adjusted to critically dampen, overdampe, or underdampe the vehicle suspension via variable dampers 281.

[0055] Accordingly, the torque control of the various powertrain components can be monitored by the vehicle system control 12 using a local torque control for the motor 110, the transmission 125, the electric machine 120 and the brakes 218, which is provided via the motor control 111B, the electric machine control 252, the transmission control 254 and the brake control 141.

[0056] As an example, an engine torque output can be controlled by adjusting a combination of ignition timing, fuel pulse width, fuel pulse rate, and / or air charge, thereby controlling the throttle opening (e.g., 62B) and / or valve timing, valve lift, and boost pressure for turbocharged or supercharged engines. In the case of a diesel engine, the controller 12 can control the engine torque output by controlling a combination of fuel pulse width, fuel pulse rate, and air charge. In all cases, engine control can be performed on a cylinder-by-cylinder basis to control the engine torque output.

[0057] The control unit of the electric machine 252 can control the torque output and the generation of electrical energy from the electric machine 120 by adjusting the current flowing to and from the field and / or armature windings of the electric machine 120, as is known in the art.

[0058] The transmission control unit 254 can receive the torque of the transmission output shaft from the torque sensor 272. Alternatively, the sensor 272 can be a position sensor or a torque and position sensor. If the sensor 272 is a position sensor, the transmission control unit 254 can count shaft position pulses over a predetermined time interval to determine the transmission output shaft speed. The transmission control unit 254 can also differentiate a transmission output shaft speed to determine the transmission output shaft acceleration. The transmission control unit 254, the engine control unit 111B, and the vehicle system control unit 12 can also receive additional transmission information from the sensors 277, which include, among others, pressure sensors of the pump output line, hydraulic pressure sensors of the transmission (e.g.,The transmission control unit may include fluid pressure sensors of the transmission clutch, electric motor temperature sensors, BISG temperature sensors, shift selector position sensors, synchronizer position sensors, and ambient temperature sensors. The transmission control unit may also receive a requested transmission state (e.g., requested gear or park mode) from the shift selector 279, which may be a lever, switch, or other device.

[0059] The brake control unit 141 receives wheel speed information via the wheel speed sensor 195 and brake requests from the vehicle system control unit 12. The brake control unit 141 can also receive brake pedal position information from the brake pedal sensor (e.g. 157) located in Fig. The information shown in 1A is received directly or via CAN 299. The brake controller 141 can initiate braking in response to a wheel torque command from the vehicle system controller 12. The brake controller 141 can also provide anti-lock braking and vehicle stability braking to improve braking and vehicle stability. Thus, the brake controller 141 can provide the vehicle system controller 12 with a wheel torque limit (e.g., a threshold for negative wheel torque that should not be exceeded) so that negative electric motor torque does not cause the wheel torque limit to be exceeded. For example, if the controller 12 outputs a negative wheel torque limit of 50 Nm, the electric motor torque can be adjusted to provide less than 50 Nm (e.g., 49 Nm) of negative torque at the wheels, taking into account the transmission ratio.

[0060] A positive torque can be transmitted to the vehicle wheels 131 in a direction that begins at the motor 110 and ends at the wheels 131. Thus, in the power transmission 200, the motor 110 is positioned upstream of the gearbox 125 according to the direction of the positive torque flow in the power transmission 200. The gearbox 125 is positioned upstream of the electric machine 120, and the BISG 142 can be positioned upstream of the motor 110 or downstream of the motor 110 and upstream of the gearbox 125.

[0061] Fig. Figure 3 shows a detailed representation of a dual-clutch transmission (DCT) 125. The engine crankshaft 40B is shown as a clutch connected to a clutch housing 393. Alternatively, a shaft can couple the crankshaft 40B to the clutch housing 393. The clutch housing 393 can rotate according to the rotation of the crankshaft 40B. The clutch housing 393 can include a first clutch 126 and a second clutch 127. Furthermore, the first clutch 126 and the second clutch 127 each have an associated first clutch disc 390 and a second clutch disc 391, respectively. In some examples, the clutches can be wet clutches, oil-bath clutches (for cooling), or dry disc clutches. The engine torque can be transmitted from the clutch housing 393 to either the first clutch 126 or the second clutch 127. The first transmission clutch 126 transmits torque between the engine 110 (shown in Figure 3) and the engine 127. Fig. 1A) and the first transmission input shaft 302. Thus, the clutch housing 393 can be referred to as the drive side of the first transmission clutch 126, and 126A can be referred to as the output side of the first transmission clutch 126. The second transmission clutch 127 transmits torque between the motor 110 (in Fig. 1A shown) and the second transmission input shaft 304. Thus, a clutch housing 393 can be referred to as the drive side of a second transmission clutch 127, and 127A can be referred to as the output side of the second transmission clutch 127.

[0062] As discussed above, a gearbox 128 can contain a plurality of gears. It has two gearbox input shafts, including a first gearbox input shaft 302 and a second gearbox input shaft 304. The second gearbox input shaft 304 is hollow, while the first gearbox input shaft 302 is solid and sits coaxially within the second gearbox input shaft 304. For example, the first gearbox input shaft 302 can have a plurality of fixed gears. For example, the first gearbox input shaft 302 can have a first fixed gear 306 to receive the first gear 320, a third fixed gear 310 to receive the third gear 324, a fifth fixed gear 314 to receive the fifth gear 329, and a seventh fixed gear 318 to receive the seventh gear 332. In other words, the first transmission input shaft 302 can be selectively coupled to a variety of odd gears.The second transmission input shaft 304 can include a second fixed gear 308 for receiving a second gear 322 or a reverse gear 328, and further, a fourth fixed gear 316 for receiving either a fourth gear 326 or a sixth gear 330. It is understood that both the first transmission input shaft 302 and the second transmission input shaft 304 can be connected to each of the first clutch 126 and second clutch 127, respectively, via ribs (not shown) on the outside of each shaft. In a normal rest state, both the first clutch 302 and the second clutch 304 are held open, for example, by springs (not shown), etc., so that no torque from the engine (e.g., 110) can be transmitted to the first transmission input shaft 302 or the second transmission input shaft 304 when each of the respective clutches is in an open state.In response to the engagement of the first clutch 126, engine torque can be transmitted to the first transmission input shaft 302, and in response to the engagement of the second clutch 127, engine torque can be transmitted to the second transmission input shaft 304. During normal operation, transmission electronics ensure that only one clutch is engaged at any given time.

[0063] The gearbox 128 can further include a first countershaft 340 and a second countershaft 342. The gears on the first countershaft 340 and the second countershaft 342 are not fixed but can rotate freely. In the exemplary DCT 125, the first countershaft 340 includes the first gear 320, the second gear 322, the sixth gear 330, and the seventh gear 332. The second countershaft 342 includes the third gear 324, the fourth gear 326, the fifth gear 329, and the reverse gear 328. Both the first countershaft 340 and the second countershaft 342 can transmit torque to the gear 353 via a first output pinion 350 and a second output pinion 352, respectively.In this way, both reduction gears can transmit torque to the output shaft 362 via the first output pinion 350 as well as the second output pinion 352, with the output shaft transmitting torque to a rear drive unit 136 (shown in . Fig. 1A) can be transmitted, which can enable each of the drive wheels (e.g. 131 of Fig. 1A) rotates at different speeds, for example when performing turning maneuvers.

[0064] As discussed above, the first gear 320, the second gear 322, the third gear 324, the fourth gear 326, the fifth gear 329, the sixth gear 330, the seventh gear 332, and the reverse gear 328 are not attached to the reduction gears (e.g., 340 and 342) but are free to rotate. Thus, synchronizing devices can be used to ensure that each of the gears aligns with the rotational speed of the reduction gears, and they can also be used to lock the gears. In the exemplary DCT 125, four synchronizing devices are shown, for example, a first synchronizing device 370, a second synchronizing device 374, a third synchronizing device 380, and a fourth synchronizing device 382.The first synchronizing device 370 includes a corresponding first shift fork 372, the second synchronizing device 374 includes a corresponding shift fork 376, the third synchronizing device 380 includes a corresponding third shift fork 378, and the fourth synchronizing device 384 includes a corresponding fourth shift fork 382. Each of the shift forks can enable movement of each corresponding synchronizing device to lock or unlock one or more gears. For example, the first synchronizing device 340 can be used to lock either the first gear 320 or the seventh gear 332. The second synchronizing device 374 can be used to lock either the second gear 322 or the sixth gear 330. The third synchronizing device 380 can be used to lock either the third gear 324 or the fifth gear 329.The fourth synchronizing device 384 can be used to lock either the fifth gear 326 or the reverse gear 328. In each case, the movement of the synchronizing devices can be achieved via the shift forks (e.g., 372, 376, 378, and 382), which move each of the corresponding synchronizing devices into the desired position.

[0065] The movement of the synchronizing devices via the shift forks can be effected by a transmission control module (TCM) 254 and shift fork actuators 388, the TCM 254 performing the above-mentioned function with respect to Fig. The TCM 254, as discussed in section 2, can include the shift fork actuators. These actuators can be electrically, hydraulically, or by a combination of both. Hydraulic power can be provided via pump 312 and / or pump 367. The TCM 254 can collect input signals from various sensors, evaluate the input, and control various actuators accordingly. Inputs used by the TCM 254 include, but are not limited to, the transmission range (P / R / N / D / S / L, etc.), vehicle speed, engine speed and torque, throttle angle, engine temperature, ambient temperature, steering angle, brake inputs, transmission input shaft speed (for both the first transmission input shaft 302 and the second transmission input shaft 304), and vehicle attitude (pitch). The TCM can control actuators via an open-loop controller to enable adaptive control.For example, the adaptive control allows the TCM 254 to detect and adjust clutch engagement points, clutch friction coefficients, and the position of synchronizing device assemblies. The TCM 254 can also control a first clutch actuator 389 and a second clutch actuator 387 to open and close the first clutch 126 and the second clutch 127, respectively. The first clutch actuator 389 and the second clutch actuator 387 can be operated electrically, hydraulically, or by a combination of both. Hydraulic power can be provided by pump 312 and / or pump 367.

[0066] Thus, the TCM 254 receives inputs from various sensors 277, as shown above. Fig. 2 discussed, the various sensors can include pump outlet line pressure sensors, transmission hydraulic pressure sensors (e.g., transmission clutch fluid pressure sensors), electric motor temperature sensors, shift selector position sensors, synchronizer position sensors, and ambient temperature sensors. The various sensors 277 can further include wheel speed sensors (e.g., 195), engine speed sensors, engine torque sensors, throttle position sensors, engine temperature sensors, steering angle sensors, and inertial sensors (e.g., 199). The inertial sensors can include one or more of the following: longitudinal acceleration, lateral acceleration, upward acceleration, yaw rate, roll rate, and pitch rate sensors, as discussed above in relation to Fig. 1A discussed.

[0067] The sensors 277 may further include an input shaft speed (ISS) sensor, which may be a magnetoresistive sensor, and wherein one ISS sensor may be included for each gearbox input shaft (e.g., one for the first gearbox input shaft 302 and one for the second gearbox input shaft 304). The sensors 277 may further include an output shaft speed (OSS) sensor, which may be a magnetoresistive sensor and may be mounted on the output shaft 362. The sensors 277 may further include a transmission range (TR) sensor and shift fork position sensors to detect the position of shift forks (e.g., 372, 376, 378, 382).

[0068] It is understood that the DCT 125 functions as described here. For example, when the first clutch 126 is engaged, engine torque can be supplied to the first transmission input shaft 302. When the first clutch 126 is engaged, it is understood that the second clutch 127 is disengaged, and vice versa. Depending on which gear is locked when the first clutch 126 is engaged, power can be transmitted via the first transmission input shaft 302 to either the first reduction gear 340 or the second reduction gear 342, and further transmitted via either the first pinion 350 or the second pinion 352 to the output shaft 362.Alternatively, depending on which gear is locked, power can be transmitted via the second transmission input shaft 304 to either the first reduction gear 340 or the second reduction gear 342 when the second clutch 127 is engaged, and it can furthermore be transmitted via either the first pinion 350 or the second pinion 352 to the output shaft 362. When torque is transmitted to one reduction gear (e.g., the first output shaft 340), it is understood that the other reduction gear (e.g., the second output shaft 342) can continue to rotate, even though only one shaft is directly driven by the input. More specifically, the shaft that is not engaged (e.g., the second reduction gear 342) can continue to rotate when it is indirectly driven by the output shaft 362 and the corresponding pinion (e.g., 352).

[0069] The DCT 125 can enable gear preselection, thus allowing rapid gear changes with minimal torque loss during shifting. For example, power from the engine can be transmitted to the first input shaft 302 and the first reduction gear 340 when the first gear 320 is locked via the first synchronizer 370 and the first clutch 126 is engaged (and the second clutch 127 is disengaged). While the first gear 320 is engaged, the second gear 322 can simultaneously be locked via the second synchronizer 374. Because the second gear 322 is locked, the second input shaft 304 can be rotated, with its speed matched to the vehicle speed in second gear. In an alternative case, where one gear is engaged in the other reduction gear (e.g.,If the second reduction gear 342) is preselected, the reduction gear also rotates when it is driven by the output shaft 362 and the pinion 352.

[0070] When a gear change is initiated by the TCM 254, only the clutches need to be actuated to open the first clutch 126 and close the second clutch 127. Furthermore, the engine speed can be reduced outside the TCM to correspond to the upshift. With the second clutch 127 engaged, power can be transferred from the engine to the second input shaft 304 and the first reduction gear 340, and further transmitted via the pinion 350 to the output shaft 362. After the gear change is complete, the TCM 254 can conveniently preselect the next gear. For example, based on inputs it receives from various sensors 277, the TCM 254 can select either a higher or a lower gear. In this way, a gear change can be achieved quickly and with minimal loss of engine torque delivered to the output shaft 362.

[0071] The dual-clutch transmission 300 may, in some examples, include a parking gear 360. A parking pawl 363 may face the parking gear 360. When a shift lever is moved into the park position, the parking pawl 363 may engage with the parking gear 360. Engagement of the parking pawl 363 with the parking gear 360 may be achieved by a parking pawl spring 364, or, for example, by a cable (not shown), a hydraulic piston (not shown), or an electric motor (not shown). When the parking pawl 363 engages with the parking gear 360, the drive wheels (e.g., 130, 131) of a vehicle may be locked. On the other hand, in response to a shift lever being moved from the park position to another selection (e.g. driving position), the parking lock pawl 363 can move in such a way that the parking lock pawl 363 can be disengaged from the parking gear 360.

[0072] In some examples, an electric transmission pump 312 can supply hydraulic fluid from a transmission oil pan 311 to compress a spring 364, thereby releasing the parking pawl 363 from the parking gear 360. The electric transmission pump 312 can, for example, be powered by an onboard energy storage device (e.g., 132). In some examples, a mechanical pump 367 can additionally or alternatively supply hydraulic fluid from the transmission oil pan 311 to compress the spring 364, thereby releasing the parking pawl 363 from the parking gear 360. Although not explicitly shown, the mechanical pump can be driven by the motor (e.g., 110) and mechanically coupled to the clutch housing 393. In some examples, a parking pawl valve 361 can regulate the flow of hydraulic fluid to the spring 364.

[0073] Thus, the system enables Fig. 1A-3, a system comprising: an internal combustion engine; a dual-clutch transmission coupled to the engine; an axle having an electrically controlled limited-slip differential, the axle being coupled to the dual-clutch transmission; an electric machine directly coupled to the axle; and a controller containing executable instructions stored in non-volatile memory for dictating a limited-slip differential torque in response to a requested regenerative torque of the electric machine and a first-wheel limiting braking torque. The system further comprises additional instructions to dictate the torque to zero in response to the requested regenerative torque of the electric machine, subtracted by a value of two and multiplied by the first-wheel limiting braking torque, being less than zero.The system also includes additional instructions to dictate the torque to zero in response to the fact that the limiting braking torque for the first wheel is essentially equivalent to a limiting braking torque for a second wheel.

[0074] The system incorporates the principle that the first and second limit braking torques depend on the coefficient of friction of the road surface, with the first limit braking torque depending on a normal load on the first wheel and the second limit braking torque depending on a normal load on the second wheel. The system incorporates the principle that the regeneration torque is based on the output torque of a motor.

[0075] With reference to Fig. Section 4 presents a first example method for operating a hybrid power transmission to increase the conversion of a vehicle's kinetic energy into electrical energy. The method of Fig. 4 can be integrated into the system of Fig. 1A-3 can be integrated and thus interact with each other. Furthermore, at least parts of the process can be... Fig. 4. executable instructions are included, stored in non-volatile memory, while other parts of the procedure can be carried out via a controller that converts operating states of devices and actuators in the physical world.

[0076] In procedure 402, procedure 400 assesses whether a vehicle brake pedal is being applied or whether an autonomous controller is requesting vehicle braking. Procedure 400 can assess that a vehicle brake pedal is being applied in response to the position of a brake pedal. Procedure 400 can also assess whether vehicle braking is being requested in response to the value of a parameter in the controller's memory. If procedure 400 assesses that a brake pedal is being applied, the answer is yes, and procedure 400 proceeds to 404. Otherwise, the answer is no, and procedure 400 returns to 402.

[0077] In procedure 404, method 400 determines a coefficient of friction (µ) between a tire and a road surface. Furthermore, method 400 determines normal forces for each wheel that can participate in regenerative braking. For example, the forces in Fig. The wheels 131 shown in Figure 1A are involved in regenerative braking, since, according to the illustration, the wheels 131 are in mechanical communication with the electric machine 120 via the axle 122. In one example, the coefficient of friction between the tire and the road surface can be determined as described in US Patent 4,794,538, which is hereby incorporated in its entirety by reference for all purposes.

[0078] The normal forces for the wheels 131 are the forces that each wheel transmits to the road surface in a direction perpendicular to the road surface. In one example, the normal forces are determined using strain gauges located on each drive wheel. Alternatively, the normal forces for drive wheels, including a predetermined number of occupants and fuel quantity, can be stored in a memory and adjusted depending on the lateral and longitudinal acceleration to determine the normal forces applied to the drive wheels. For example, the normal force applied to a left rear wheel can be mathematically described as follows: LHN=f(FM,Quer_a,La¨ngs_a,Sph,Rs,Sb) where LH NThe normal load on the left rear wheel is defined as follows: `f` is a function that returns a value for the normal load on the left rear wheel. The argument `FM` is the vehicle mass, the argument `Quer_a` is the lateral acceleration determined by a sensor, the argument `Läng_a` is the longitudinal acceleration determined by sensors, the argument `Sph` is the empirically determined center of gravity height stored in memory, the argument `Rs` is the measured wheelbase of the vehicle, and the argument `Sb` is the measured track width of the vehicle. Values ​​in the function `f` can be empirically determined and stored in memory. The normal load on the right rear wheel can be determined in a similar manner.

[0079] Method 400 transitions to 406 after the coefficient of friction and normal forces have been determined for each wheel that can participate in regenerative braking by transferring kinetic energy of the vehicle to the electric machine.

[0080] In 406, the procedure 400 determines a maximum braking torque available for each wheel that can participate in regenerative braking (e.g., the drive wheels 131 of Fig. 1A). The maximum braking torque for the left rear drive wheel can be called the first limiting braking torque (Tq_BremsMax1). The maximum braking torque for a right rear drive wheel can be called the second limiting braking torque (Tq_BremsMax2). In an example, method 400 determines the first limiting braking torque as a function of My and the normal load of the left rear wheel. The first limiting braking torque can be expressed mathematically as follows: LHMax_Brems=f(LHN,My,R) where LH Max_Brems The maximum or upper limit braking torque for the left rear wheel is f, which is a function that yields a value for the braking torque of the left rear wheel, the argument LH NThe normal load on the left rear wheel is given by , the argument My is a friction coefficient determined as previously explained, and the argument R is the tire radius. Values ​​in the function f can be determined empirically and stored in memory. The maximum braking torque of the right rear wheel can be determined as follows: RHMax_Brems=f(RHN,My,R) where RH Max_Brems The maximum or upper limit braking torque for the right rear wheel is the RH argument. N The normal load of the right rear wheel is given, the argument My is a coefficient of friction determined as previously described, and the argument R is the tire radius. The remaining variables correspond to the description above. Procedure 400 proceeds to 408 after the first limiting braking torque and the second limiting braking torque have been determined.

[0081] In procedure 408, procedure 400 assesses whether the electric limited-slip differential (eLSD) (e.g., a limited-slip differential that has an electrically operated clutch) is active. In an example, procedure 400 can assess that the eLSD is active if the torque of an electrically operated differential clutch (e.g., a measure of torque that the differential clutch is requested to transmit from its drive side to its driven side) is non-zero. The torque of the electrically operated differential clutch increases when the pressure applied to engage the clutch increases. The pressure applied to the electrically operated differential clutch can be increased by sending an electrical signal to the electrically operated differential clutch.The electrical signal can increase the hydraulic pressure, which in some examples is used to engage the electrically operated differential lock. If procedure 400 determines that the electrically operated differential lock is active, the answer is yes, and procedure 400 proceeds to 410. Otherwise, the answer is no, and procedure 400 proceeds to 430.

[0082] At 430, the procedure 400 determines a measure of regenerative braking that is applied via a first half-shaft to the lesser of the first limit braking torque and the second limit braking torque determined at 406. The measure of regenerative braking determined for the second half-shaft corresponds to the regenerative braking torque applied to the first half-shaft. The electric machine in the power transmission (e.g., 120 of Fig. 1A) provides a regenerative braking torque equal to the regenerative braking torque applied to the first half-shaft plus the regenerative braking torque applied to the second half-shaft. The relationships can be expressed mathematically as follows: Tq_regen1=min(Tq_BremsMax1,Tq_BremsMax2); Tq_regen2=Tq_regen1 Tq_gesRegen=Tq_regen1+Tq_regen2 where Tq_regen1 is the regenerative torque applied to the first wheel, Tq_regen2 is the regenerative torque applied to the second wheel, Tq_BremsMax1 is the maximum braking torque of the first wheel, Tq_BremsMax2 is the maximum braking torque of the second wheel, min is a function that selects a minimum value (e.g., the lesser of the argument values) among the arguments and assumes that both arguments are positive, and Tq_gesRegen is the total regenerative torque supplied to the power transmission (e.g., the electric motor of the rear drive unit and / or the integrated starter-generator) by the electric motor to provide the regenerative torques applied to the first and second wheels. Procedure 400 terminates after the regenerative braking torque of the first and second half-shafts has been applied.

[0083] At 410, procedure 400 determines the current torque of the eLSD clutch. In an example where the eLSD engages and disengages the eLSD clutch in response to half-shaft speeds and other half-shaft conditions, the eLSD outputs a torque of the eLSD clutch to the vehicle control unit 12. The relationship between the torque transmitted through the differential clutch (e.g., the differential clutch torque) and the torques at the half-shafts of the drive axle is shown in the following equation: Tq_clutchTF=Trq_high−Trq_low where Tq_KupplungTF is the clutch torque, Trq_hoch is the one of the two drive wheels that has a higher torque load (e.g. an outer wheel when the vehicle is driving around a curve) and Trq_gering is the one of the drive wheels that has a lower torque load (e.g. an inner wheel when the vehicle is driving around a curve).

[0084] In further examples, a locking effect for an LSD clutch with helical gears can be mathematically described as follows: Trq_hoch=Trq_gering⋅DMV where Trq_high is the drive wheel with the higher torque load (e.g., an outer wheel when the vehicle is cornering), Trq_low is the drive wheel with the lower torque load (e.g., an inner wheel when the vehicle is cornering), and DMV is the torque distribution between the left and right drive wheels, which depends on the clutch design. When the differential is open, the regenerative torque at each wheel is the same, as it is defined by the wheel with the lowest maximum torque. The regenerative braking torque can be increased when the differential clutch is engaged or at least partially closed. The regenerative torque for the wheel with the lower torque corresponds to the maximum torque of the wheel with the lower torque.The regenerative torque for the wheel with the higher or greater torque corresponds to the maximum torque of the wheel with the lower torque plus the clutch torque. Procedure 400 transitions to 412 after the torque of the eLSD or LSD clutch has been determined.

[0085] In procedure 412, procedure 400 assesses whether the maximum braking torque of the first wheel (e.g., the limiting torque of the first wheel) is less than the maximum braking torque of the second wheel (e.g., the limiting torque of the second wheel). If yes, the answer is yes, and procedure 400 proceeds to 420. Otherwise, the answer is no, and procedure 400 proceeds to 414.

[0086] At 420, procedure 400 sets the regenerative braking torque of the first wheel to the maximum braking torque for the first wheel (e.g., the limiting torque of the first wheel). Furthermore, procedure 400 sets the regenerative braking torque of the second wheel to the minimum of the maximum braking torque of the first wheel plus the amount of torque that the differential clutch can transmit (e.g., the current differential clutch torque) or the maximum braking torque of the second wheel. The electric machine in the power transmission (e.g., 120 of Fig. 1A) provides a regenerative braking torque equal to the regenerative braking torque applied to the first half-shaft plus the regenerative braking torque applied to the second half-shaft. The relationships can be expressed mathematically as follows: Tq_regen1=Tq_BremsMax1 Tq_regen2=min(Tq_BremsMax1+Tq_KupplungTF,Tq_BremsMax2) Tq_gesRegen=Tq_regen1+Tq_regen2 where Tq_regen1 is the regenerative torque applied to the first wheel, Tq_regen2 is the regenerative torque applied to the second wheel, Tq_BremsMax1 is the maximum braking torque of the first wheel, Tq_BremsMax2 is the maximum braking torque of the second wheel, Tq_KupplungTF is the amount of torque that the differential clutch can transmit (e.g., the current differential clutch torque), min is a function that selects a minimum value (e.g., the lesser of the argument values) from among arguments, and Tq_gesRegen is the total regenerative braking torque applied to the power transmission by the electric machine of the rear drive unit and / or the integrated starter / generator to provide the regenerative torques applied to the first and second wheels. Procedure 400 proceeds to the end.

[0087] In procedure 400, method 414 sets the regenerative braking torque of the second wheel to the maximum braking torque for the second wheel (e.g., the limiting torque of the second wheel). Furthermore, method 400 sets the regenerative braking torque of the first wheel to the minimum of the maximum braking torque of the second wheel plus the amount of torque that the differential clutch can transmit (e.g., the current differential clutch torque) or the maximum braking torque of the first wheel. The electric machine in the power transmission (e.g., 120 of Fig. 1A) provides a regenerative braking torque equal to the regenerative braking torque applied to the first half-shaft plus the regenerative braking torque applied to the second half-shaft. The relationships can be expressed mathematically as follows: Tq_regen2=Tq_BremsMax2 Tq_regen1=min(Tq_BremsMax2+Tq_KupplungTF,Tq_BremsMax1) Tq_gesRegen=Tq_regen1+Tq_regen2 where Tq_regen1 is the regenerative torque applied to the first wheel, Tq_regen2 is the regenerative torque applied to the second wheel, Tq_BremsMax1 is the maximum braking torque of the first wheel, Tq_BremsMax2 is the maximum braking torque of the second wheel, min is a function that selects a minimum of the arguments, Tq_KupplungTF is the amount of torque that the differential clutch can transmit (e.g., the current differential clutch torque), and Tq_gesRegen is the total regenerative braking torque. which is applied by the electric machine to the power transmission to provide the regenerative moments applied to the first and second wheels.

[0088] Procedure 400 is coming to an end.

[0089] In this way, method 400 can utilize the regenerative braking torque generated by an electric machine in the power transmission (e.g., 142 or 120 of Fig. 2) is provided, to improve the conversion of a vehicle's kinetic energy into electrical energy. Furthermore, Method 400 can enhance regenerative braking without causing the drive wheels to lock during braking. Method 400 also adjusts the degree of regenerative braking in response to a torque applied by a differential coupling (e.g., a coupling in the differential that can be selectively engaged to reduce the possibility of wheel slip).

[0090] With reference to Fig. Section 5 presents a second example method for operating a hybrid power transmission to increase the conversion of a vehicle's kinetic energy into electrical energy. The method of Fig. 5 can be integrated into the system of Fig. 1A-3 can be integrated and thus interact with each other. Furthermore, at least parts of the process can be... Fig. 5 are integrated as executable instructions stored in non-volatile memory, while other parts of the procedure can be carried out via a controller that converts operating states of devices and actuators in the physical world.

[0091] In procedure 502, procedure 500 assesses whether a vehicle brake pedal is being applied or whether an autonomous controller is requesting vehicle braking. Procedure 500 can assess that a vehicle brake pedal is being applied in response to the position of a brake pedal. Procedure 500 can assess whether vehicle braking is being requested in response to the value of a parameter in the controller's memory. If procedure 500 assesses that a brake pedal is being applied, the answer is yes, and procedure 500 proceeds to 504. Otherwise, the answer is no, and procedure 500 returns to 502.

[0092] In procedure 504, method 500 determines a coefficient of friction between a tire and a road surface. Furthermore, method 500 determines normal forces for each wheel that can participate in regenerative braking. For example, the forces in Fig. The wheels 131 shown in Figure 1A are involved in regenerative braking, since, according to the illustration, the wheels 131 are in mechanical communication with the electric machine 120 via the half-shaft 122. As an example, the coefficient of friction between the tire and the road surface can be determined as described in US 4,794,538 A, which is hereby incorporated in its entirety by reference for all purposes.

[0093] In one example, the normal forces are determined using strain gauges located on each drive wheel. Alternatively, the normal forces for drive wheels, including a predetermined number of occupants and fuel quantity, can be stored in a memory and adjusted depending on the lateral and longitudinal acceleration to determine the normal forces applied to the drive wheels. For example, the normal force applied to a right rear wheel can be mathematically described as follows: RHN=f(FM,Quer_a,La¨ngs_a,Sph,Rs,Sb) where RH N where f is the normal load on the right rear wheel, f is a function that yields a value for the normal load on the right rear wheel, and FM is the vehicle mass. The argument Quer_a is the lateral acceleration determined by a sensor, the argument Längs_a is the longitudinal acceleration determined by sensors, the argument Sph is the empirically determined center of gravity height stored in memory, the argument Rs is the measured wheelbase of the vehicle, and the argument Sb is the measured track width of the vehicle. Values ​​in the function f can be empirically determined and stored in memory. The normal load of the left rear wheel can be determined in a similar way.

[0094] Method 500 proceeds to 506 after the coefficient of friction and normal forces have been determined for each wheel that can participate in regenerative braking by transferring kinetic energy of the vehicle to the electric machine.

[0095] In 506, the procedure 500 determines a maximum braking torque available for each wheel that can participate in regenerative braking (e.g., the drive wheels 131 of Fig. 1A). The maximum braking torque for the left rear drive wheel can be called the first limiting braking torque (Tq_BremsMax1). The maximum braking torque for a right rear drive wheel can be called the second limiting braking torque (Tq_BremsMax2). In an example, method 400 determines the first limiting braking torque as a function of My and the normal load of the left rear wheel. The first limiting braking torque can be expressed mathematically as follows: LHMax_Brems=f(LHN,My,R) where LH Max_Brems The maximum or upper limit braking torque for the left rear wheel is f, which is a function that yields a value for the braking torque of the left rear wheel, the argument LH NThe normal load on the left rear wheel is given by , the argument My is a friction coefficient determined as previously explained, and R is the tire radius. Values ​​in the function f can be determined empirically and stored in memory. The maximum braking torque of the right rear wheel can be determined as follows: RHMax_Brems=f(RHN,My,R) where RH Max_Brems the maximum or upper limit braking torque for the right rear wheel and the RH argument N The normal load on the right rear wheel is given, the argument My is a coefficient of friction determined as previously described, and R is the tire radius. The remaining variables correspond to the description above. Procedure 500 proceeds to 508 after the first limiting braking torque and the second limiting braking torque have been determined.

[0096] In procedure 508, method 500 determines the difference between a potential demand for regenerative braking torque and the maximum braking torque available at the wheels. Method 500 determines a torque limit or upper limit of the electric machine. In one example, the torque limit or upper limit of the electric machine may depend on the temperature of the electric machine. The torque limit or upper limit of the electric machine can be determined by indexing a table or function of empirically determined values ​​for the torque limit of the electric machine using the temperature of the electric machine. The table or function outputs a limit for the regenerative torque of the electric machine (Tq_motLim), that is, a regenerative torque of the electric machine that must not be exceeded.Alternatively, the method 500 can obtain a torque limit or an upper limit of the electric machine from a control of the electric machine.

[0097] Method 500 also determines a power charging limit of the battery or electrical energy storage device in the power transmission torque range. A battery or electrical energy storage device may not have the capacity to store more than a limiting amount of current generated by a certain amount of renewable energy. For example, if a battery has a high state of charge, it may be able to deliver a small amount of current generated by a small amount of renewable torque input to the electric machine. In one example, the battery torque limit may depend on the battery state of charge. The battery-based torque limit, or the upper limit of the battery torque limit, can be determined by indexing a table or function of empirically determined values ​​for the battery torque limit using the battery state of charge.The table or function outputs a limit for the battery's regenerative torque (Tq_BattLadeLim), i.e., a battery torque that must not be exceeded. This battery torque can correspond to the amount of current the battery can deliver during regenerative braking.

[0098] Procedure 500 also determines a driver-requested braking torque (Tq_BremsAnf). In one example, the output of a brake position sensor is fed into a table or function of empirically determined values ​​for the braking request. The table or function outputs the driver-requested braking torque based on the brake pedal position. A potential regenerative torque request is determined by taking a minimum of the electric motor's regenerative torque limit, the battery's regenerative torque limit, and the driver-requested braking torque. The potential regenerative torque request can be expressed mathematically as follows: Tq_regenAnf=min(Tq_motLim,TqBattLadeLim,Tq_BremsAnf)

[0099] Where Tq_regenAnf is the potential regenerative torque requirement and min is a function that selects a minimum value from the arguments, assuming that the arguments have a positive sign. Method 500 also determines a torque difference between the potential regenerative torque requirement and the first and second limit braking torques. The difference can be expressed mathematically as follows: Tq_Diff=Tq_regenAnf−(2*min(Tq_BremsMax1,Tq_BremsMax2)) where Tq_Diff is the torque difference between the potential regenerative torque requirement, Tq_BremsMax1 is the maximum braking torque of the first wheel, Tq_BremsMax2 is the maximum braking torque of the second wheel, and min is a function that selects a minimum of the arguments. Procedure 500 proceeds to 510 after the torque difference has been determined.

[0100] In procedure 510, procedure 500 assesses whether a value for the moment difference Tq_Diff is less than or equal to zero. If so, the answer is yes, and procedure 500 proceeds to 522. Otherwise, the answer is no, and procedure 500 proceeds to 512.

[0101] In procedure 500, method 500 holds the eLSD in an open state where the differential coupling torque is zero. Furthermore, method 500 sets the regenerative torque applied to the first wheel (Tq_regen1) and the regenerative torque applied to the second wheel (Tq_regen2) to half of the requested regenerative braking torque. The regenerative torques can be mathematically described as follows: Tq_regen1=Tq_regen2=0.5*Tq_regenReq Tq_gesRegen=Tq_regen1+Tq_regen2

[0102] The torque of the electric motor of the rear drive unit and / or the torque of the integrated starter / generator is set to the value of Tq_gesRegen to provide the requested braking torque. Procedure 500 then proceeds to the end.

[0103] In procedure 512, procedure 500 assesses whether the maximum braking torque of the first wheel (Tq_BremsMax1) is equal to or substantially equal to the maximum braking torque of the second wheel (Tq_BremsMax2) (e.g., within the range of 20 Nm). If yes, the answer is yes, and procedure 500 proceeds to 524. Otherwise, the answer is no, and procedure 500 proceeds to 514.

[0104] At 524, procedure 500 holds the eLSD in an open state where the torque of the differential coupling is zero. Furthermore, procedure 500 sets the regenerative torque applied to the first wheel (Tq_regen1) to the maximum braking torque of the first wheel, and procedure 500 sets the regenerative torque applied to the second wheel (Tq_regen2) to the maximum braking torque of the second wheel. The regenerative torques can be mathematically described as follows: Tq_regen1=Tq_BremsMax1 Tq_regen2=Tq_BremsMax2 Tq_gesRegen=Tq_regen1+Tq_regen2

[0105] The torque of the electric machine is set to the value of Tq_gesRegen to provide the requested braking torque. Procedure 500 then proceeds to its end.

[0106] In procedure 500, method 514 determines a requirement for a measure of torque to be transmitted by the differential coupling, or the torque that the differential coupling is required to transmit. For example, method 500 can determine a maximum torque that the differential coupling can transmit (Tq_CouplingMax) by accessing an empirically determined value stored in a memory of the controller. For example, the maximum torque that the differential coupling can transmit can be expressed mathematically as follows: Tq_ClutchMax=f(Clutch_Kfg,Clutch_Temp) where Tq_KupplungMax is the maximum or upper limit of torque that the differential coupling can transmit, f is a function of empirically determined maximum torques that the differential coupling can transmit, Kupplung_Kfg is the configuration of the differential coupling, and Kupplung_Temp is the temperature of the differential coupling.

[0107] Method 500 also determines a difference between the maximum braking torque of the second wheel and the maximum braking torque of the first wheel (Tq_RLDiff). The amount of torque that the differential clutch may be required to transmit is determined by taking a minimum or lesser value of the maximum torque that the differential clutch can transmit, the torque difference between the potential regenerative torque requirement, and the difference between the maximum braking torque of the second wheel and the maximum braking torque of the first wheel. The torque that the differential clutch can transmit can be mathematically described by the following equations: Tq_RLDiff=abs(Tq_BremsMax2−Tq_BremsMax1) Tq_KupplungTFAnf=min(Tq_KupplungMax,Tq_RLDiff,Tq_Diff) where Tq_RLDiff is the difference between the maximum braking torque of the second wheel and the maximum braking torque of the first wheel, abs is a function that takes an absolute value from the arguments, Tq_KupplungTFAnf is the torque that the differential clutch is requested to transmit, and the other variables correspond to the description above. Procedure 500 transitions to 516.

[0108] In procedure 500, method 516 assesses whether the maximum braking torque for the first wheel is less than the maximum braking torque for the second wheel (e.g., Tq_BremsMax1). <Tq_BremsMax2). Falls ja, lautet die Antwort Ja und das Verfahren 500 geht zu 518 über. Anderenfalls lautet die Antwort Nein und das Verfahren 500 geht zu 530 über.

[0109] At 518, procedure 500 dictates the differential clutch torque to a value of Tq_clutchTFAnf to improve the transfer of the vehicle's kinetic energy to the electric machine. Additionally, procedure 500 sets the regenerative braking torque of the first wheel to the maximum braking torque for the first wheel (e.g., the limiting torque of the first wheel). Furthermore, procedure 500 sets the regenerative braking torque of the second wheel to the maximum braking torque of the first wheel plus the torque that the differential clutch is required to transmit. The electric machine in the power transmission (e.g., 120 of Fig. 1A) provides a regenerative braking torque equal to the regenerative braking torque applied to the first half-shaft plus the regenerative braking torque applied to the second half-shaft. The relationships can be expressed mathematically as follows: Tq_regen1=Tq_BremsMax1 Tq_regen2=Tq_BremsMax1+Tq_KupplungTFAnf Tq_gesRegen=Tq_regen1+Tq_regen2 where Tq_regen1 is the regenerative torque applied to the first wheel, Tq_regen2 is the regenerative torque applied to the second wheel, Tq_BremsMax1 is the maximum braking torque of the first wheel, Tq_BremsMax2 is the maximum braking torque of the second wheel, Tq_KupplungTFAnf is the torque requested to transmit by the differential clutch, and Tq_gesRegen is the total regenerative braking torque transmitted to the power transmission by the electric machine of the rear drive unit and / or the integrated starter-generator to provide the regenerative torques applied to the first and second wheels. Procedure 500 proceeds to the end.

[0110] At 530, procedure 500 dictates the differential clutch torque to a value of Tq_clutchTFAnf to improve the transfer of the vehicle's kinetic energy to the electric machine. Additionally, procedure 500 sets the regenerative braking torque of the second wheel to the maximum braking torque for the second wheel (e.g., the limiting torque of the second wheel). Furthermore, procedure 500 sets the regenerative braking torque of the first wheel to the maximum braking torque of the second wheel plus the torque that the differential clutch is required to transmit. The electric machine in the power transmission (e.g., 120 of Fig. 1A) provides a regenerative braking torque equal to the regenerative braking torque applied to the first half-shaft plus the regenerative braking torque applied to the second half-shaft. The relationships can be expressed mathematically as follows: Tq_regen2=Tq_BremsMax2 Tq_regen1=Tq_BremsMax2+Tq_KupplungTFAnf Tq_gesRegen=Tq_regen1+Tq_regen2 where Tq_regen1 is the regenerative torque applied to the first wheel, Tq_regen2 is the regenerative torque applied to the second wheel, Tq_BremsMax1 is the maximum braking torque of the first wheel, Tq_BremsMax2 is the maximum braking torque of the second wheel, Tq_KupplungTFAnf is the torque requested to transmit by the differential clutch, and Tq_gesRegen is the total regenerative braking torque transmitted by the electric machine to the power transmission to provide the regenerative torques applied to the first and second wheels. Procedure 500 proceeds to the end.

[0111] In this way, the Method 500 can dictate the differential coupling torque and the regenerative torque of each wheel to improve the conversion of the vehicle's kinetic energy into electrical energy. This method can be particularly effective when a vehicle enters a curve or operates on a road surface with a split coefficient of friction (e.g., the coefficient of friction for a road surface under a first wheel differs from the coefficient of friction for a road surface under a second wheel).

[0112] Therefore, the methods described herein enable a power transmission method comprising: adjusting a differential clutch torque (e.g., a torque transmitted by the differential clutch) in response to a difference between the braking torque of a second wheel and the braking torque of a first wheel; and adjusting a regenerative torque of an electric machine in response to the braking torque of the first wheel and the braking torque of the second wheel plus the torque required to transmit a differential clutch. The method involves the braking torque of the first wheel and the braking torque of the second wheel being dependent on a coefficient of friction of the road surface, wherein the braking torque of the first wheel is dependent on a normal load on the first wheel, and wherein the braking torque of the second wheel is dependent on a normal load on the second wheel.

[0113] In some examples, the procedure involves the requested clutch transmission torque being a minimum of a clutch transmission limit torque, a difference between the braking torque of the second wheel and the braking torque of the first wheel, and a regenerative torque request minus a lesser of the braking torque of the first wheel and the braking torque of the second wheel, multiplied by two. The procedure involves dictating the regenerative torque of the electric machine by issuing commands to an electric machine of a rear-wheel-drive unit and an integrated starter / generator. The procedure involves the electric machine being directly coupled to a vehicle's rear axle.The procedure involves dictating the clutch transmission torque to zero in response to the fact that the difference between the second limit braking torque and the first limit braking torque is essentially zero (e.g., less than 20 Nm). The procedure further includes dictating the differential clutch transmission torque to zero in response to the fact that a desired regeneration torque is less than twice the first wheel's braking torque or the second wheel's braking torque.

[0114] The procedure of Fig. 4 and Fig. Paragraph 5 also provides a method for operating a power transmission, comprising: setting a regenerative torque of an electric machine to a value multiplied by two in response to the electronic limited-slip differential not being activated; and setting the regenerative torque of the electric machine to a value of the sum of a first-wheel braking torque and the first-wheel braking torque and a clutch torque (e.g., a measure of torque currently transmitted by a clutch) in response to the electronic limited-slip differential being activated. The method implies that the clutch torque is a torque that an electronic limited-slip differential can transmit. The method also implies that the clutch torque of the electronic limited-slip differential is zero when the electric limited-slip differential is not activated.The method further includes adjusting the regenerative torque of the electric machine (e.g., the torque provided by the electric machine when it charges a battery) to a sum of the braking torque of a second wheel, the second braking torque, and the clutch torque. The method further includes estimating the braking torque of the first wheel in response to the coefficient of friction of the road surface and a normal load on one wheel.

[0115] In some examples, the procedure further includes estimating the braking torque of the second wheel in response to a coefficient of friction of the road surface and a normal load on one wheel. The procedure involves multiplying by two in response to the fact that an electronic limited-slip differential is not activated, resulting in a value less than the braking torque of the first wheel and the braking torque of the second wheel. The procedure involves adjusting the regenerative torque of an electric machine that is directly coupled to an axle.

[0116] At this point, we will refer to Fig. 6. Referenced in which a prophetic sequence of regenerative braking according to the procedure of Fig. 4 is shown. The sequence of Fig. 6 can be determined using the procedure of Fig. 4 will be provided, which is in conjunction with the system of Fig. 1A-3 is working.

[0117] The first course from the top into Fig. Figure 6 shows the operating state of an electrically controlled limited-slip differential (eLSD) over time. The eLSD can be in an active state, labeled "ACTIVE," or in a deactivated state, labeled "ACTIVE" under a line on the vertical axis. The horizontal axis represents time, and time increases from the left to the right side of the figure.

[0118] The second course from the top in Fig. Figure 6 shows the maximum braking torque for a first drive wheel as a function of time. The vertical axis represents the maximum or limit of the braking torque, and the maximum braking torque increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side.

[0119] The third course from the top in Fig. Figure 6 shows the maximum braking torque for a second drive wheel as a function of time. The vertical axis represents the maximum or limit of the braking torque, and the maximum braking torque increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side.

[0120] The fourth course from the top in Fig. Figure 6 shows the regenerative braking torque for the first drive wheel as a function of time. The vertical axis represents the regenerative braking torque for the first wheel, and this torque increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right.

[0121] The fifth course from the top in Fig. Figure 6 shows the regenerative braking torque for the second drive wheel as a function of time. The vertical axis represents the regenerative braking torque for the second wheel, and this torque increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right.

[0122] The sixth course from the top in Fig. Figure 6 shows the clutch torque of an eLSD differential (e.g., an actual clutch transmission torque or a measure of torque that the differential clutch can transmit, and the actual clutch transmission torque can vary depending on a force applied to close the differential clutch) as a function of time. The vertical axis represents the clutch torque of an eLSD differential, and the clutch torque increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

[0123] At time T0, curve 602 of the eLSD state indicates that the eLSD is active. The eLSD can adjust the torque transmitted between the first and second drive wheels when active. The maximum braking torque for the first wheel is at a higher level, as indicated by curve 604. The maximum braking torque for the second wheel is also at a higher level, as indicated by curve 606. The regenerative braking torque for the first wheel is zero, as indicated by curve 608. The regenerative braking torque for the second wheel is zero, as indicated by curve 610. The torque transmitted via the differential clutch is zero, as indicated by curve 612. These conditions indicate a vehicle traveling at constant speed in a straight line.

[0124] At time T1, the vehicle begins to enter a curve, with the first wheel being the inside wheel (e.g., the wheel that travels a shorter distance through the curve) and the second wheel being the outside wheel (e.g., the wheel that travels a longer distance through the curve). Braking is requested as the vehicle enters the curve, indicated by the regenerative braking torque of the first wheel increasing to a higher level and the regenerative braking torque of the second wheel increasing to a higher level. The eLSD torque (e.g., the amount of torque the differential can transfer from its drive side to its output side) also begins to increase as the vehicle enters the curve. The maximum braking torque for the first and second wheels remains at a high level.

[0125] Between time T1 and time T2, the eLSD remains active, and the maximum braking torque for the first and second wheels decreases. The maximum braking torque for the first wheel is lower than the maximum braking torque for the second wheel because it is the inside wheel in the corner, and the vehicle's weight shifts from the inside wheel to the outside wheel. Furthermore, the maximum braking torque for both the inside and outside wheels decreases when the vehicle's weight shifts to the front wheels (not shown). The regenerative braking torque for the first wheel increases in response to a request for increased braking when entering the corner (not shown) and then decreases after reaching its maximum braking torque for the first wheel.Similarly, the regenerative braking torque for the second wheel increases in response to a request for increased braking when entering a curve (not shown) and then decreases after reaching the maximum braking torque for the first wheel plus the torque transmitted via the differential clutch. The eLSD torque increases to transfer torque to the second wheel.

[0126] At time T2, the vehicle begins to exit the curve, and the braking request is released, indicated by the regenerative braking torque for the first and second wheels returning to zero. The maximum braking torque for the first and second wheels begins to increase as the vehicle exits the curve and stops braking. Furthermore, the torque of the eLSD clutch is gradually reduced as the vehicle exits the curve.

[0127] At time T3, the vehicle fully exits the curve and continues driving on a straight path. The maximum braking torque for the first and second wheels returns to their respective levels prior to time T1. The regenerative braking torques for the first and second wheels remain at zero, and the eLSD torque is also zero, resulting in an open differential and even torque distribution to the first and second wheels. The eLSD remains active.

[0128] Between time points T3 and T4, the eLSD is deactivated, so the differential clutch transmits no torque. The maximum braking torque for the first and second wheels remains at higher levels. The regenerative braking torque for the first and second wheels remains at zero, and the torque of the eLSD clutch is zero.

[0129] At time T4, the vehicle begins to enter a second curve; again, the first wheel is the inside wheel and the second wheel is the outside wheel. Braking is requested as the vehicle enters the curve, indicated by the regenerative braking torque of the first wheel increasing to a higher level and the regenerative braking torque of the second wheel increasing to a higher level. The eLSD torque remains at zero, as the eLSD is deactivated. The maximum braking torque for the first and second wheels remains at a higher level.

[0130] Between time points T4 and T5, the eLSD remains deactivated, and the maximum braking torque for the first and second wheels decreases. The maximum braking torque for the first wheel is lower than the maximum braking torque for the second wheel because it is the inside wheel in the corner, and the vehicle's weight shifts from the inside wheel to the outside wheel. Furthermore, the maximum braking torque for both the inside and outside wheels decreases when the vehicle's weight shifts to the front wheels (not shown). The regenerative braking torque for the first wheel increases in response to a request for increased braking when entering the corner (not shown) and then decreases after reaching its maximum braking torque for the first wheel.Similarly, the regenerative braking torque for the second wheel increases in response to a request for increased braking when entering a curve (not shown) and then decreases, after the maximum braking torque for the first wheel, because the differential is open, thus aligning the torque capacity of the first and second wheels with the lower maximum braking torque of the first and second wheels. The eLSD torque remains zero.

[0131] At time T5, the vehicle begins to exit the curve, and the braking request is released, indicated by the regenerative braking torque for the first and second wheels dropping to zero. The maximum braking torque for the first and second wheels begins to increase as the vehicle exits the curve and stops braking. The torque of the eLSD clutch remains at zero.

[0132] In this way, the regenerative braking torque for drive wheels can be adjusted in response to a lower maximum braking torque of two drive wheels. Furthermore, the regenerative braking torque of the outer wheel can be increased when cornering to increase the amount of charge fed to the vehicle's battery or electrical energy storage device.

[0133] At this point, we will refer to Fig. 7 Referenced in which a prophetic sequence of regenerative braking according to the procedure of Fig. 5 is shown. The sequence of Fig. 7 can be determined using the procedure of Fig. 5 will be provided, which is in conjunction with the system of Fig. 1A-3 is working. The one in Fig. The 7 shown curves exhibit the same characteristics. Fig. The six variables shown are therefore omitted for the sake of brevity.

[0134] At time T10, the eLSD state trace 702 indicates that the eLSD is not active. In this example, the eLSD may be inactive in response to driving conditions and the procedure of Fig. 5 can be activated and deactivated. The maximum braking torque for the first wheel is at a higher level, as shown by curve 704. The maximum braking torque for the second wheel is also at a higher level, as shown by curve 706. The regenerative braking torque for the first wheel is zero, as shown by curve 708. The regenerative braking torque for the second wheel is zero, as shown by curve 710. The torque transmitted via the differential clutch is zero, as shown by curve 712. These conditions indicate a vehicle traveling at constant speed in a straight line.

[0135] At time T11, the vehicle begins to enter a curve, with the first wheel being the inside wheel and the second wheel the outside wheel. Braking is requested as the vehicle enters the curve, indicated by an increase in the regenerative braking torque of the first wheel and the regenerative braking torque of the second wheel. The eLSD is activated shortly after the braking request; however, the eLSD can also be activated in response to the vehicle's lateral acceleration. The torque demand of the eLSD differential clutch begins to increase as the vehicle enters the curve. The maximum braking torque for the first and second wheels remains at a high level.

[0136] Between time points T11 and T12, the eLSD remains active, and the maximum braking torque for the first and second wheels decreases. The maximum braking torque for the first wheel is lower than the maximum braking torque for the second wheel because it is the inside wheel in the corner, and the vehicle's weight shifts from the inside wheel to the outside wheel. Furthermore, the maximum braking torque for both the inside and outside wheels decreases when the vehicle's weight shifts to the front wheels (not shown). The regenerative braking torque for the first wheel increases in response to a request for increased braking when entering the corner (not shown) and then decreases after reaching its maximum braking torque for the first wheel.Similarly, the regenerative braking torque for the second wheel increases in response to a request for increased braking when entering a curve (not shown) and then decreases after reaching the maximum braking torque for the first wheel plus the torque transmitted via the differential clutch. The eLSD torque request increases to transfer torque to the second wheel.

[0137] At time T12, the vehicle begins to exit the curve, and the braking request is released, indicated by the regenerative braking torque for the first and second wheels dropping to zero. The maximum braking torque for the first and second wheels begins to increase as the vehicle exits the curve. Furthermore, the torque request from the eLSD clutch is gradually reduced as the vehicle exits the curve.

[0138] At time T13, the vehicle fully exits the curve and continues driving on a straight path. The maximum braking torque for the first and second wheels returns to their respective levels prior to time T11. The regenerative braking torques for the first and second wheels remain at zero, and the eLSD torque request also returns to zero, providing an open differential and even torque delivery to the first and second wheels. The eLSD is deactivated in response to exiting the curve.

[0139] In this way, an eLSD can be switched on and off in response to a vehicle entering and exiting a curve. The regenerative braking torque of the drive wheels can be adjusted in response to the torque required to transmit by the eLSD differential clutch, in order to enhance the amount of charge fed to the vehicle's electrical energy storage device while the vehicle is cornering.

[0140] It should be noted that the exemplary control and estimation routines contained herein can be used in conjunction with different engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-volatile memory and executed by the control system, which includes the control unit in combination with the various sensors, actuators, and other engine hardware. Furthermore, parts of the methods can be physical actions performed in the real world to change the state of a device. The specific routines described herein can represent one or more from any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like.Thus, various actions, processes, and / or functions shown can be performed in the sequence presented, in parallel, or omitted in some cases. Likewise, the processing sequence is not strictly necessary to achieve the characteristics and benefits of the examples described here and is provided primarily to facilitate illustration and description. One or more of the depicted processes, steps, and / or functions can be repeated depending on the specific strategy employed.Furthermore, the described actions, processes, and / or functions can graphically represent code that is to be programmed into non-volatile memory of the computer-readable storage medium in the engine control system, whereby the described actions are executed by carrying out the instructions in a system that includes the various engine hardware components in combination with the electronic control unit. One or more of the procedure steps described here can be omitted as required.

[0141] It is understood that the configurations and processes disclosed herein are exemplary and that these specific examples are not to be interpreted restrictively, as numerous variations are possible. For example, the aforementioned technology can be applied to V-6, I-4, I-6, V-12, 4-cylinder boxer, and other engine types. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and combinations, and other features, functions, and / or properties disclosed herein.

Claims

[1] Methods (400, 500) for power transmission, comprising: Setting a clutch torque (612, 712) of a clutch (191) of a differential (193) that drives a first wheel (131) and a second wheel (131), in response to a difference between a braking torque of the second wheel (131) and a braking torque of the first wheel (131); and Setting a regenerative torque of an electric machine (120) in response to the braking torque of the first wheel (131) and the braking torque of the second wheel (131) and the clutch torque (612, 712). [2] Method (400, 500) according to claim 1, wherein the braking torque of the first wheel (131) and the braking torque of the second wheel (131) depend on a coefficient of friction of the road surface, wherein the first braking torque depends on a normal load on the first wheel (131) and wherein the second braking torque depends on a normal load on the second wheel (131). [3] Method (400, 500) according to claim 1, wherein the clutch torque (612, 712) is a lesser value of a clutch limit torque, a difference between the braking torque of the second wheel (131) and the braking torque of the first wheel (131) and a regenerative torque requirement less a lesser value of the braking torque of the first wheel (131) and the braking torque of the second wheel (131), multiplied by a value of two. [4] Method (400, 500) according to claim 1, wherein dictating the regeneration moment of the electric machine (120) includes issuing commands to an electric machine (120) of a rear drive unit (136) and an integrated starter / generator (142). [5] Method (400, 500) according to claim 1, wherein the electric machine (120) is directly coupled to a rear axle (122) of a vehicle. [6] Method (400, 500) according to claim 1, wherein the clutch torque (612, 712) is dictated to zero in response to the fact that the difference between the braking torque of the second wheel (131) and the torque of the first wheel (131) is zero. [7] Method (400, 500) according to claim 1, further comprising dictating the clutch torque (612, 712) of the differential (193) to zero in response to the fact that a desired regeneration torque is less than twice a lesser of the braking torque of the first wheel (131) or the braking torque of the second wheel (131). [8] System (100), comprising: a motor (110); a dual-clutch transmission (125) which is coupled to the engine (110) via a drive shaft (129); a rear drive unit (136) comprising an electrically controlled limited-slip differential (193) and an electrically controlled differential clutch (191) which adjusts the torque transmission to a first half-shaft (122a) on which a first wheel (131) is arranged and a second half-shaft (122b) on which a second wheel (131) is arranged, wherein the rear drive unit (136) is coupled to the dual-clutch transmission (125); an electric machine (120) directly coupled to the rear drive unit (136); and a control (12) which contains executable instructions stored in a non-volatile memory for setting a limited-slip torque (612, 712) of the differential (193) in response to a requested regenerative torque based on brake pedal inputs of the electric machine (120) and a braking torque of the first wheel (131). [9] System (100) according to claim 8, further comprising additional instructions to dictate the torque (612, 712) to zero in response to the fact that the requested regenerative torque of the electric machine (120), subtracted by a value of two, multiplied by the braking torque of the first wheel (131), is less than zero. [10] System (100) according to claim 8, further comprising additional instructions to dictate the torque (612, 712) to zero in response to the fact that the braking torque of the first wheel (131) corresponds to a braking torque of the second wheel (131). [11] System (100) according to claim 10, wherein the braking torque of the first wheel (131) and the braking torque of the second wheel (131) depend on a coefficient of friction of the road surface, wherein the braking torque of the first wheel (131) depends on a normal load on the first wheel (131) and wherein the braking torque of the second wheel (131) depends on a normal load on the second wheel (131).

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