System and method for operating a vehicle powertrain

Abstract

A method and system are described to provide a powertrain or driveline for operating a hybrid vehicle including two electric machines and a transmission. In one example, vehicle propulsion is maintained while determining transmission operating parameters to improve transmission operation. In particular, a rear drive unit maintains vehicle speed and monitors torque transmitted via the output of the transmission.

Description

Technical Field

[0001] The present description relates to systems and methods for determining operating characteristics of a transmission and operating a powertrain system in response to the operating characteristics. The systems and methods may be applicable to a powertrain system including a transmission located between two electric machines in the powertrain system. Background Art

[0002] A hybrid vehicle may include an engine, an electric motor, and a step ratio transmission. The transmission allows different vehicle speeds to be achieved while allowing the engine to operate within a desired speed range. By operating the engine within the desired speed range, engine emissions and performance may be improved. However, as vehicles age, the constant shifting of gears in a step ratio transmission may require constant adjustment of transmission control parameters. Vehicle occupants may find it objectionable to wait for vehicle parameter adjustments when they wish to arrive at their destination. Furthermore, since internal combustion piston engines burn at fixed crankshaft intervals, it may be difficult to separate combustion artifacts from the parameters or variables being adjusted. Therefore, it is desirable to provide a way to adjust transmission control parameters with minimal disruption to vehicle occupants. Summary of the invention

[0003] The inventors herein have recognized the above-mentioned problems and have developed a method of operating a powertrain system, which includes: at least partially engaging a gear synchronizer or a band brake while rotating a transmission input shaft via an electric motor, holding a transmission output shaft stopped while rotating the transmission input shaft via the electric motor; and adjusting transmission shifting in response to torque transmitted via the gear synchronizer or the belt.

[0004] The operating state of the transmission component can be determined by rotating the transmission component via the motor and adjusting the transmission shift in response to the transmitted torque while keeping the transmission output shaft stopped. In one example, the transmission component state can be adjusted while the motor rotates the input shaft of the transmission without rotating the output shaft of the transmission. Changes in the motor current can indicate the torque transmitted via the transmission shift element. The state of the shift element can be adjusted while the vehicle is parked or stopped during the driving cycle so that the vehicle occupants are not disturbed. In other examples, the vehicle speed can be maintained while the transmission parameters are determined so that the transmission control parameters can be adjusted with a low likelihood of disturbing the vehicle occupants.

[0005] According to the present invention, there is provided a method for operating a power transmission system, comprising:

[0006] at least partially engaging a gear synchronizer or a belt while rotating the transmission input shaft via the electric machine, the transmission output shaft remaining stationary while rotating the transmission input shaft via the electric machine; and

[0007] Transmission shifting is coordinated in response to torque transmitted via a gear synchronizer or belt.

[0008] According to one embodiment of the present invention, a synchronizer is included in a dual clutch transmission.

[0009] According to one embodiment of the invention, a belt is included in a transmission including a planetary gear set.

[0010] According to one embodiment of the invention, the method further comprises operating the motor in a speed control mode in which the motor follows a desired speed.

[0011] According to one embodiment of the present invention, the torque transmitted via the gear synchronizer or the belt depends on the current supplied to the motor when the gear synchronizer or the belt is at least partially engaged while rotating the transmission input shaft via the motor.

[0012] According to one embodiment of the invention, the transmission output shaft is kept stopped while the transmission input shaft is rotated via the wheel brakes.

[0013] According to one embodiment of the invention, the transmission output shaft is held stationary via a parking pawl.

[0014] According to the present invention, there is provided a method for operating a power transmission system, comprising:

[0015] rotating a first side of a transmission input clutch at a first speed via a first electric machine while rotating a transmission output shaft at a second speed via a second electric machine;

[0016] at least partially engaging the transmission input clutch; and

[0017] Transmission shifting is regulated in response to torque transmitted via the transmission input clutch.

[0018] According to an embodiment of the present invention, the method further includes operating the first electric machine in a speed control mode while rotating the first side of the transmission input clutch via the first electric machine.

[0019] According to an embodiment of the present invention, the method further comprises adjusting a transfer function describing operation of a transmission input clutch in response to a change in torque of the first electric machine when the first electric machine is operated in the speed control mode.

[0020] According to one embodiment of the present invention, the method further includes operating the second electric machine in a speed control mode and maintaining vehicle speed in response to the torque increase transmitted via the transmission input clutch.

[0021] According to an embodiment of the present invention, the method further includes operating the engine at a constant torque while rotating the first side of the transmission input clutch via the first electric machine.

[0022] According to one embodiment of the invention, the first speed is greater than the second speed multiplied by a ratio of engaged gears of the transmission.

[0023] According to one embodiment of the invention, the first speed is less than the second speed multiplied by a ratio of an engaged gear of the transmission.

[0024] According to the present invention, there is provided a system comprising:

[0025] First motor;

[0026] a transmission selectively mechanically connected to the first electric machine via an input clutch;

[0027] a second electric machine included in a rear drive unit mechanically connected to an output shaft of the transmission; and

[0028] A controller including executable instructions stored in a non-transitory memory for operating the second motor in a speed control mode while changing the output torque of the first motor while an input clutch and a gear clutch of the transmission are closed, and instructions for operating the transmission in response to currents supplied to the first motor and the second motor immediately before changing the output torque of the first motor and currents supplied to the first motor and the second motor immediately after changing the output torque of the first motor.

[0029] According to one embodiment of the present invention, the system further includes instructions for operating the transmission with the input clutch closed and the gear clutch closed.

[0030] According to one embodiment of the present invention, the system further includes instructions for estimating a transmission torque ratio in response to currents supplied to the first and second electric machines immediately before and immediately after changing the output torque of the first electric machine.

[0031] According to one embodiment of the invention, the command to operate the transmission in response to the electrical current includes changing a transmission gear.

[0032] According to one embodiment of the invention, operating the second electric machine in the speed control mode includes maintaining a constant vehicle speed.

[0033] According to an embodiment of the present invention, the system further estimates the transmission efficiency based on currents supplied to the first and second motors immediately before and after changing the output torque of the first motor.

[0034] The present description may provide several advantages. In particular, the method may improve the operation of the transmission during the service life of the transmission. Furthermore, the method may improve the operation of the transmission without disturbing the vehicle occupants. Additionally, the method may provide improved control parameter estimation.

[0035] It should be understood that the above summary is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1A is a schematic diagram of a hybrid vehicle powertrain;

[0037] Figure 1B is a simplified diagram of an engine of a hybrid vehicle powertrain;

[0038] Figure 2 is a schematic diagram of a hybrid vehicle powertrain including controllers for various powertrain components;

[0039] Figure 3A is a schematic diagram of a dual clutch transmission that may be located in a hybrid vehicle powertrain;

[0040] Figure 3B is a schematic diagram of a planetary gear transmission that may be located in a hybrid vehicle powertrain;

[0041] Figure 4 is a flow chart of a first method for operating a hybrid vehicle powertrain;

[0042] Figure 5 is based on Figure 4 Method for predicting an operation sequence of a powertrain system;

[0043] Figure 6 is a flow chart of a second method for operating a hybrid vehicle powertrain;

[0044] Figure 7 is based on Figure 6 Method for predicting an operation sequence of a powertrain system;

[0045] Figure 8 is a flow chart of a third method for operating a hybrid vehicle powertrain; and

[0046] Fig. 9 is based on Figure 8 A method for predicting an operation sequence of a powertrain system. DETAILED DESCRIPTION

[0047] The following description relates to systems and methods for operating a powertrain of a hybrid vehicle. Figures 1A-3B An example hybrid vehicle system is shown that includes a driveline having an engine, an integrated starter / generator, a dual clutch transmission, and a rear drive unit having an electric machine located downstream of the dual clutch transmission. Figure 4 , 6 8 show methods for operating a hybrid powertrain or powertrain system. In particular, these methods describe methods of identifying system control parameters to improve powertrain operation and control. Figure 5 , 7 and 9 show the Figure 4 , 6 and an example operation sequence of the method of 8.

[0048] Figure 1A An example vehicle propulsion system 100 is shown for a vehicle 121. The vehicle propulsion system 100 includes at least two power sources, including an internal combustion engine 110 and an electric motor 120. The electric motor 120 can be configured to utilize or consume energy sources different from the engine 110. For example, the engine 110 can consume a liquid fuel (e.g., gasoline) to produce an engine output, while the electric motor 120 can consume electrical energy to produce a motor output. As such, a vehicle having the propulsion system 100 can be referred to as a hybrid electric vehicle (HEV). Throughout Figure 1A In the description of FIG. 1 , mechanical connections between various components are shown with solid lines, and electrical connections between various components are shown with dotted lines.

[0049] The vehicle propulsion system 100 has a front axle (not shown) and a rear axle 122. In some examples, the rear axle may include two half shafts (e.g., a first half shaft 122a and a second half shaft 122b). The vehicle propulsion system 100 also has front wheels 130 and rear wheels 131. The rear axle 122 is connected to the motor 120 and the transmission 125 via a drive shaft 129. The rear axle 122 may be driven purely electrically and only by the motor 120 (e.g., in an electric-only drive or propulsion mode, the engine does not burn air and fuel or is not running), may be driven in a hybrid manner (e.g., parallel mode) via the motor 120 and the engine 110, or may be driven only by the engine 110 (e.g., in an engine-only propulsion mode) in a manner that the internal combustion engine is running. The rear drive unit 136 may transmit power from the engine 110 or the motor 120 to the axle 122 to generate rotation of the drive wheel 131. The rear drive unit 136 may include a gear set, a differential 193, and an electronically controlled differential clutch 191 that regulates the torque transmitted to the bridge 122a and the bridge 122b. In some examples, the electronically controlled differential clutch 191 can transmit the torque of the electronically controlled differential clutch via a CAN (Controller Area Network) bus 299. When the electronically controlled differential clutch is open, the torque transmitted to the bridges 122a and 122b can be equal. When the electronically controlled differential clutch 191 is partially closed (e.g., slipping causes the speed input to the clutch to be different from the speed output of the clutch) or closed, the torque transmitted to the bridge 122a can be different from the torque transmitted to the bridge 122b. The rear drive unit 136 may also include one or more clutches (not shown) to separate the transmission 125 and the motor 120 from the wheels 131. The rear drive unit 136 may be directly connected to the motor 120 and the bridge 122.

[0050] Transmission 125 Figure 1A 1 is shown connected between the engine 110 and the motor 120 assigned to the rear axle 122. In one example, the transmission 125 is a dual clutch transmission (DCT). In the example where the transmission 125 is a DCT, the DCT may include a first clutch 126, a second clutch 127, and a gearbox 128. The DCT 125 outputs torque to drive the shaft 129 to provide torque to the wheels 131. As will be described below with respect to Figure 2 As discussed in further detail, the transmission 125 may be shifted by selectively opening and closing the first clutch 126 and the second clutch 127 .

[0051] The motor 120 may receive power from an onboard electrical energy storage device 132. In addition, the motor 120 may provide a generator function to convert engine output or vehicle kinetic energy into electrical energy, which may be stored at the energy storage device 132 for later use by the motor 120, the integrated starter / generator 142, or the belt-type integrated starter generator 142a. The first inverter system controller (ISC1) 134 may convert the AC power generated by the motor 120 into DC power for storage at the energy storage device 132, and vice versa.

[0052] In some examples, energy storage device 132 may be configured to store electrical energy that may be supplied to other electrical loads (in addition to the motor) onboard the vehicle, including cabin heating and air conditioning, engine starter, headlights, cabin audio and video systems, etc. As non-limiting examples, energy storage device 132 may include one or more batteries and / or capacitors.

[0053] The control system 14 may communicate with one or more of the engine 110, the motor 120, the energy storage device 132, the integrated starter / generator 142, the transmission 125, etc. The control system 14 may receive sensory feedback information from one or more of the following: the engine 110, the motor 120, the energy storage device 132, the integrated starter / generator 142, the transmission 125, etc. In addition, the control system 14 may send a control signal to one or more of the engine 110, the motor 120, the energy storage device 132, the transmission 125, etc. in response to such sensory feedback. The control system 14 may receive an indication of an operator-requested vehicle propulsion system output from a human operator 102 or an autonomous controller. For example, the control system 14 may receive sensory feedback from a pedal position sensor 194 in communication with a pedal 192. The pedal 192 may schematically refer to an accelerator pedal. Similarly, the control system 14 may receive an indication of an operator-requested vehicle braking via a human operator 102 or an autonomous controller. For example, the control system 14 may receive sensory feedback from a pedal position sensor 157 in communication with a brake pedal 156.

[0054] The energy storage device 132 may periodically receive electrical energy from a power source 180 (e.g., a fixed grid) that resides outside the vehicle (e.g., not part of the vehicle), as indicated by arrow 184. As a non-limiting example, the vehicle propulsion system 100 may be configured as a plug-in hybrid electric vehicle (HEV), whereby electrical energy may be supplied from the power source 180 to the energy storage device 132 via a power transmission cable 182. During a recharging operation of the energy storage device 132 from the power source 180, the power transmission cable 182 may electrically connect the energy storage device 132 and the power source 180. In some examples, the power source 180 may be connected at the inlet port 150. Additionally, in some examples, a charging status indicator 151 may display the charging status of the energy storage device 132.

[0055] In some examples, electrical energy from power source 180 may be received by charger 152. For example, charger 152 may convert alternating current (AC) from power source 180 into direct current (DC) for storage at energy storage device 132. In addition, DC / DC converter 153 may convert DC power from charger 152 from one voltage to another voltage. In other words, DC / DC converter 153 may act as a type of power converter.

[0056] When operating the vehicle propulsion system to propel the vehicle, power transmission cable 182 may be disconnected between power source 180 and energy storage device 132. Control system 14 may identify and / or control the amount of electrical energy stored at the energy storage device, which may be referred to as the state of charge (SOC).

[0057] In other examples, the power transmission cable 182 may be omitted and electrical energy may be received wirelessly from the power source 180 at the energy storage device 132. For example, the energy storage device 132 may receive electrical energy from the power source 180 via one or more of the following: electromagnetic induction, radio waves, and electromagnetic resonance. Thus, it should be understood that any suitable method may be used to recharge the electrical energy storage device 132 from a power source that is not part of the vehicle. In this manner, the motor 120 may propel the vehicle by utilizing an energy source other than the fuel utilized by the engine 110.

[0058] The energy storage device 132 includes an energy storage device controller 139 and a power distribution module 138. The energy storage device controller 139 can provide charge balancing between energy storage elements (e.g., battery cells) and communicate with other vehicle controllers (e.g., controller 12). The power distribution module 138 controls the flow of power into and out of the energy storage device 132.

[0059] The vehicle propulsion system 100 may also include an ambient temperature / humidity sensor 198 and sensors dedicated to indicating the occupancy state of the vehicle (e.g., an onboard camera 105, a seat load unit 107, and a door sensing technology 108). The vehicle system 100 may also include an inertial sensor 199. The inertial sensor 199 may include one or more of the following: a longitudinal sensor, a lateral sensor, a vertical sensor, a yaw sensor, a roll sensor, and a pitch sensor (e.g., an accelerometer). The axes of yaw, pitch, roll, lateral acceleration, and longitudinal acceleration are as shown. As an example, the inertial sensor 199 may be connected to a restraint control module (RCM) (not shown) of the vehicle, which includes a subsystem of the control system 14. The control system may adjust the engine output and / or wheel braking in response to one or more sensors 199 to increase vehicle stability. In another example, the control system may adjust the active suspension system 111 in response to input from the inertial sensor 199. The active suspension system 111 may include an active suspension system having hydraulic, electrical and / or mechanical devices, and an active suspension system that controls vehicle height on an axle-by-axle basis (e.g., vehicle height for the front and rear axles), on a single corner basis (e.g., vehicle height for four corners independently controlled), or an active suspension system that controls a single vehicle height for the entire vehicle. Data from the inertial sensor 199 may also be transmitted to the controller 12, or alternatively, the sensor 199 may be electrically connected to the controller 12. The normal load or force applied to the driven wheel 131 may be determined via the load sensor 188.

[0060] One or more tire pressure monitoring sensors (TPMS) may be connected to one or more wheel tires in a vehicle. Figure 1A A tire pressure sensor 197 is shown connected to the wheel 131 and configured to monitor the pressure in the tire of the wheel 131. Although not explicitly shown, it is understood that Figure 1A Each of the four tires shown in FIG. 1 may include one or more tire pressure sensors 197. In addition, in some examples, the vehicle propulsion system 100 may include a pneumatic control unit 123. The pneumatic control unit may receive information about tire pressure from the tire pressure sensors 197 and send the tire pressure information to the control system 14. The control system 14 may instruct the pneumatic control unit 123 to inflate or deflate the tires of the vehicle wheels based on the tire pressure information. Although not explicitly shown, it is understood that the pneumatic control unit 123 may be used to enable the pneumatic control unit 123 to inflate or deflate the tires of the vehicle wheels. Figure 1A. For example, the control system 14 can command the pneumatic control system unit 123 to inflate or deflate the tires associated with any of the four wheels shown in FIG. 1 . For example, the control system 14 can command the pneumatic control system unit 123 to inflate one or more tires in response to an indication of a decrease in tire pressure. Alternatively, the control system 14 can command the pneumatic control system unit 123 to deflate one or more tires in response to an indication of an increase in tire pressure. In both examples, the pneumatic control system unit 123 can be used to inflate or deflate the tires to the optimal tire pressure rating for the tires, which can extend tire life.

[0061] One or more wheel speed sensors (WSS) 195 may be connected to one or more wheels of the vehicle propulsion system 100. The wheel speed sensor may detect the rotational speed of each wheel. Such an example of a WSS may include a permanent magnet type sensor.

[0062] The vehicle propulsion system 100 may further include an accelerometer 20. The vehicle propulsion system 100 may further include an inclinometer 21.

[0063] The vehicle propulsion system 100 may further include a starter 140. The starter 140 may include an electric motor, a hydraulic motor, etc., and may be used to rotate the engine 110 so as to start the operation of the engine 110 under its own power.

[0064] The vehicle propulsion 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 the wheels (e.g., 130, 131) can maintain traction contact with the road surface based on driver input when braking, thereby preventing the wheels from locking to prevent skidding. In some examples, the BSCM may receive input from a wheel speed sensor 195.

[0065] The vehicle propulsion system 100 may further include a belt integrated starter generator (BISG) 142a. The BISG may generate electricity when the engine 110 is running, wherein the generated electricity may be used to supply electrical devices and / or charge the onboard storage device 132. Similarly, the vehicle propulsion system 100 may further include an integrated starter generator 142. The ISG (integrated starter generator) may generate electricity when the engine 110 is running, wherein the generated electricity may be used to supply electrical devices and / or charge the onboard storage device 132. Figure 1A As shown, a second inverter system controller (ISC2) 143 may receive AC power from the ISG 142 and may convert the AC power generated by the ISG 142 to DC power for storage at the energy storage device 132. The integrated starter / generator 142 may also provide torque to the engine 110 during engine starting or to supplement engine torque under other conditions.

[0066] In some examples, the vehicle propulsion system 100 may include one or more motors 135a and 135b to propel the vehicle 121 via the front wheels 130 or provide regenerative braking. The third inverter (ISC3) 147a may convert the AC power generated by the motor 135a into DC power for storage at the energy storage device 132 or provide AC power to the motor 135a to propel the vehicle 121. Similarly, the fourth inverter (ISC4) 147a may convert the AC power generated by the motor 135b into DC power for storage at the energy storage device 132 or provide AC power to the motor 135b to propel the vehicle 121. The motors 135a and 135b may be collectively referred to as front wheel motors. Alternatively, a single front wheel motor may drive the two front wheels 130 and / or provide regenerative braking to the two front wheels 130 via a bridge that may include an electronic limited slip differential as shown in 136, 191, and 193.

[0067] The vehicle propulsion system 100 may also include a power distribution box (PDB) 144. The PDB 144 may be used to route power among various circuits and accessories in the vehicle's electrical system.

[0068] The vehicle propulsion system 100 may also include a high current fuse box (HCFB) 145 , and may contain various fuses (not shown) for protecting wiring and electrical components of the vehicle propulsion system 100 .

[0069] The vehicle propulsion system 100 may also include a motor electronic coolant pump (MECP) 146. The MECP 146 may be used to circulate coolant to dissipate heat generated by at least the motor 120 and electronic systems of the vehicle propulsion system 100. As an example, the MECP may receive power from the onboard energy storage device 132.

[0070] Controller 12 may comprise a portion of control system 14. In some examples, controller 12 may be a single controller for the vehicle. Control system 14 is shown receiving information from a plurality of sensors 16 (various examples of which are described herein) and sending control signals to a plurality of actuators 81 (various examples of which are described herein). As an example, sensors 16 may include tire pressure sensors 197, wheel speed sensors 195, ambient temperature / humidity sensors 198, onboard cameras 105, seat load cells 107, door sensing technology 108, inertial sensors 199, etc. In some examples, such as those described with respect to FIG. Figure 1B , Figure 2 and Figure 3A In further detail, sensors associated with engine 110 , transmission 125 , electric machine 120 , etc. may communicate information to controller 12 regarding various states of engine, transmission, and motor operation.

[0071] The vehicle propulsion system 100 may also include a positive temperature coefficient (PTC) heater 148. As an example, the PTC heater 148 may include a ceramic material such that the ceramic material can accept a large amount of current when the resistance is low, which may result in a rapid heating of the ceramic element. However, when the element warms up and reaches a threshold temperature, the resistance may become very large and therefore may not continue to generate much heat. In this way, the PTC heater 148 may be self-regulating and may have a good level of overheat protection.

[0072] The vehicle propulsion system 100 may also include an air conditioner compressor module 149 for controlling an electric air conditioner compressor (not shown).

[0073] The vehicle propulsion system 100 may also include a vehicle acoustic sound generator for pedestrians (VASP) 154. For example, the VASP 154 may be configured to generate an audible sound via a sound generator 155. In some examples, the audible sound generated via the VASP 154 in communication with the sound generator 155 may be activated in response to a vehicle operator triggering the sound, or may be automatically activated in response to an engine speed below a threshold or detection of a pedestrian.

[0074] The vehicle propulsion system 100 may also include an onboard navigation system 17 (e.g., a global positioning system) on the dashboard 19, and the operator of the vehicle can interact with the onboard navigation system 17. The navigation system 17 may include one or more position sensors for assisting in estimating the location (e.g., geographic coordinates) of the vehicle. For example, the onboard navigation system 17 may receive a signal from a GPS (Global Positioning System) satellite (not shown) and identify the geographic location of the vehicle from the signal. In some examples, the geographic location coordinates may be transmitted to the controller 12.

[0075] The instrument panel 19 may also include a display system 18 configured to display information to the vehicle operator. As a non-limiting example, the display system 18 may include a touch screen or human-machine interface (HMI), display that enables the vehicle operator to view graphical 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 vehicle operator may communicate with an Internet site or software application (app) through the display system 18.

[0076] The instrument panel 19 may also include an operator interface 15, through which the vehicle operator can adjust the operating state of the vehicle. Specifically, the operator interface 15 may be configured to start and / or terminate the operation of the vehicle powertrain (e.g., engine 110, ISG 142, BISG 142a, DCT 125, and motor 130) according to operator input. Various examples of the operator ignition interface 15 may include an interface that requires a physical device (such as an active key) that can be inserted into the operator ignition interface 15 to start the engine 110 and start the vehicle, or can be removed to turn off the engine 110 and shut down the vehicle. Other examples may include a passive key that is communicatively connected to the operator ignition interface 15. The passive key may be configured as an electronic key chain or smart key that does not have to be inserted or removed from the ignition interface 15 to operate the vehicle engine 110. Instead, the passive key may need to be located inside or near the vehicle (e.g., within a threshold distance of the vehicle). Other examples may also additionally or alternatively use a start / stop button manually pressed by the operator to start or stop the engine 110 and start or shut down the vehicle. In other examples, remote engine start may be performed by a remote computing device (not shown) (e.g., by a cell phone or smartphone-based system where the user's cell phone sends data to a server and the server communicates with the vehicle controller 12 to start the engine).

[0077] refer to Figure 1B , showing a detailed view of an internal combustion engine 110 including a plurality of cylinders, Figure 1B 1 and 2. One cylinder is shown in FIG. 1. The engine 110 is controlled by an electronic engine controller 111B. The engine 110 includes a combustion chamber 30B and a cylinder wall 32B, in which a piston 36B is located and connected to a crankshaft 40B. The combustion chamber 30B is shown as being connected to an intake manifold 44B and an exhaust manifold 48B via corresponding intake valves 52B and exhaust valves 54B. Each intake valve 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 move relative to the crankshaft 40B. The intake valve can be deactivated and maintained in a closed state via an intake valve deactivation mechanism 59B. The exhaust valve can be deactivated and maintained in a closed state via an exhaust valve deactivation mechanism 58B.

[0078] Fuel injector 66B is shown positioned to inject fuel directly into cylinder 30B, which is known as direct injection to those skilled in the art. Alternatively, fuel can be injected into the intake port, which is known as port injection to those skilled in the art. Fuel injector 66B delivers liquid fuel in proportion to the pulse width of the signal of engine controller 111B. Fuel is delivered to fuel injector 66B by a fuel system 175B including a tank and a pump. In addition, intake manifold 44B is shown to be connected to an optional electronic throttle 62B (e.g., a butterfly valve) that adjusts the position of throttle plate 64B to control the air flow from air filter 43B and intake port 42B to intake manifold 44B. Throttle 62B controls the air flow from air filter 43B in engine air intake port 42B to intake manifold 44B. In some examples, throttle 62B and throttle plate 64B may be positioned between intake valve 52B and intake manifold 44B such that throttle 62B is a port throttle.

[0079] Distributorless ignition system 88B provides an ignition spark to combustion chamber 30B via spark plug 92B in response to engine controller 111B. Universal or Wide-area Exhaust Gas Oxygen (UEGO) sensor 126B is shown coupled to exhaust manifold 48B upstream of catalytic converter 70B in the direction of exhaust flow. Alternatively, a two-state exhaust gas oxygen sensor may be substituted for UEGO sensor 126B.

[0080] In one example, converter 70B may include multiple catalyst bricks. In another example, multiple emission control devices each having multiple bricks may be used. In one example, converter 70B may be a three-way type catalyst.

[0081] The engine controller 111B Figure 1B10 is shown as a conventional microcomputer, which includes: a microprocessor unit 102B, an input / output port 104B, a read-only memory 106B (e.g., a non-transitory memory), a random access memory 108B, a keep-alive memory 110B, and a conventional data bus. Other controllers mentioned herein may have similar processor and memory configurations. The engine controller 111B is shown as receiving various signals from sensors connected to the engine 110, including, in addition to those previously discussed, the engine coolant temperature (ECT) from the temperature sensor 112B connected to the cooling sleeve 114B; the measurement of the engine manifold pressure (MAP) from the pressure sensor 122B connected to the intake manifold 44B; the engine position sensor from the Hall effect sensor 118B sensing the position of the crankshaft 40B; the measurement of the air mass entering the engine from the sensor 120B; and the measurement of the throttle position from the sensor 58B. The air pressure (sensor not shown) can also be sensed for processing by the engine controller 111B. In a preferred aspect of the present description, engine position sensor 118B produces a predetermined number of equally spaced pulses per revolution of the crankshaft from which engine speed (RPM) can be determined. Engine controller 111B may receive input from a human / machine interface 115B, such as buttons or a touch screen display.

[0082] During operation, each cylinder in the engine 110 typically undergoes a four-stroke cycle: the cycle includes an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. Typically, during the intake stroke, the exhaust valve 54B is closed and the intake valve 52B is opened. Air is introduced into the combustion chamber 30B via the intake manifold 44B, and the piston 36B moves to the bottom of the cylinder to increase the volume within the combustion chamber 30B. The position of the piston 36B near the bottom of the cylinder and at the end of its stroke (e.g., when the combustion chamber 30B is at its maximum volume) is generally referred to by those skilled in the art as the 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 at the end of its stroke and closest to the cylinder head (e.g., when the combustion chamber 30B is at its minimum volume) is generally referred to by those skilled in the art as the top dead center (TDC). In a process hereinafter referred to as injection, fuel is introduced into the combustion chamber. In a process hereinafter referred to as ignition, the injected fuel is ignited by known ignition means (e.g., spark plug 92B) to cause combustion. During the expansion stroke, the expanding gases push piston 36B back to BDC. Crankshaft 40B converts the piston motion into rotational torque of the rotating shaft. Finally, during the exhaust stroke, exhaust valve 54B opens to release the combusted air-fuel mixture to exhaust manifold 48B, and the piston returns to TDC. Note that the above is shown only as an example, and the intake and exhaust valve opening and / or closing timings can be varied to provide positive or negative valve overlap, late intake valve closing, or various other examples.

[0083] Figure 2 is a block diagram of a vehicle 121 including a powertrain or driveline 200 . Figure 2 The powertrain system includes Figure 1A-1B Engine 110 is shown. Figure 2 of Figure 1AThe same other components are represented by the same reference numerals and will be discussed in detail below. The powertrain system 200 is shown as including a vehicle system controller 12, an engine controller 111B, a motor controller 252, a transmission controller 254, an energy storage device controller 253, and a brake controller 141 (also referred to herein as a brake system control module). The controllers can communicate via a controller area network (CAN) 299. Each controller can provide information to other controllers, such as torque output limits (e.g., torque outputs that are not exceeded by a control device or component), torque input limits (torque inputs that are not exceeded by a control device or component), torque outputs controlled by the device, sensor actuator data, diagnostic information (e.g., information about downgraded transmissions, information about downgraded engines, information about downgraded motors, information about downgraded brakes). In addition, the vehicle system controller 12 can provide commands to the engine controller 111B, the motor controller 252, the transmission controller 254, and the brake controller 141 to implement driver input requests and other requests based on vehicle operating conditions.

[0084] For example, the vehicle system controller 12 may request a desired wheel torque or wheel power level to provide a desired level of vehicle deceleration in response to the driver releasing the accelerator pedal and the vehicle speed decreasing. The desired wheel torque may be provided by the vehicle system controller 12 requesting a first braking torque from the motor controller 252 and a second braking torque from the brake controller 141, the first torque and the second torque providing the desired braking torque at the vehicle wheels 131.

[0085] In other examples, the division of control of the powertrain devices may be different than Figure 2 For example, a single controller may replace the vehicle system controller 12, the engine controller 111B, the motor controller 252, the transmission controller 254, and the brake controller 141. Alternatively, the vehicle system controller 12 and the engine controller 111B may be a single unit, while the motor controller 252, the transmission controller 254, and the brake controller 141 may be separate controllers.

[0086] In this example, the powertrain 200 can be powered by an engine 110 and an electric motor 120. In other examples, the engine 110 can be omitted. The engine 110 can be started by an engine starter (e.g., 140), an ISG 142, via a belt integrated starter / generator (BISG) 142a or via an electric motor 120. In some examples, the ISG 142 can be directly connected to the engine crankshaft at either end of the crankshaft (e.g., the front end or the rear end). The electric motor 120 (e.g., a high-voltage motor running at more than 30 volts) is also referred to as an electric motor, a motor and / or a generator in this article. In addition, the torque of the engine 110 can be adjusted via a torque actuator 204 (e.g., a fuel injector, a throttle, etc.).

[0087] BISG 142 is mechanically connected to engine 110 via belt 231. BISG 142 may be connected to a crankshaft (not shown) or a camshaft (not shown). BISG 142 may operate as a motor when supplied with power via electrical energy storage device 132 (also referred to herein as onboard energy storage device 132). BISG 142 may also operate as a generator that supplies power to electrical energy storage device 132.

[0088] The transmission 200 includes an engine 110 that can be selectively mechanically connected to the ISG 142 and the dual clutch transmission (DCT) 125 via the crankshaft 40B and the transmission disconnect clutch 287. The transmission disconnect clutch includes an input side 289 (e.g., a first side) and an output side 288 (e.g., a second side). 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 provide torque to the vehicle wheels 131. The transmission controller 254 selectively opens and closes the first clutch 126 and the second clutch 127 to shift the DCT 125. In some examples, the DCT 125 may alternatively be a Figure 3B The automatic planetary gear step ratio transmission shown in .

[0089] The gearbox 128 may include a plurality of gears. One clutch (e.g., the first clutch 126) may control odd-numbered gears 261 (e.g., the first gear, the third gear, the fifth gear, and the reverse gear), while another clutch (e.g., the second clutch 127) may control even-numbered gears 262 (e.g., the second gear, the fourth gear, and the sixth gear). Gears may be changed by utilizing this arrangement without interrupting the power flow from the engine 110 to the dual clutch transmission 125.

[0090] The electric machine 120 can be operated to provide torque to the powertrain 200 or to convert the powertrain torque into electrical energy in a regenerative mode for storage in the electrical energy storage device 132. In addition, the electric machine 120 can convert the kinetic energy of the vehicle into electrical energy for storage in the electrical energy storage device 132. The electric machine 120 is in electrical communication with the energy storage device 132. Figure 1A The starter (eg, 140 ) or BISG 142 a shown in FIG. 1 has a higher output torque capacity. In addition, the electric machine 120 directly drives the powertrain 200 , or is directly driven by the powertrain 200 .

[0091] The electrical energy storage device 132 (eg, a high voltage battery or power source) may be a battery, a capacitor, or an inductor. The motor 120 is driven by a rear drive unit 136 ( Figure 1A The motor 120 can be instructed by the motor controller 252 to operate as a motor or a generator to provide positive torque or negative torque to the powertrain 200.

[0092] In addition, frictional forces may be applied to wheels 131 by engaging friction wheel brakes 218. In one example, friction wheel brakes 218 may be engaged in response to the driver pressing his foot on a brake pedal (e.g., 192) and / or in response to instructions within brake controller 141. In addition, brake controller 141 may apply brakes 218 in response to information and / or requests made by vehicle system controller 12. In the same manner, frictional forces applied to wheels 131 may be reduced by disengaging wheel brakes 218 in response to the driver releasing his foot from the brake pedal, brake controller instructions, and / or vehicle system controller instructions and / or information. For example, vehicle brakes may apply frictional forces to wheels 131 via controller 141 as part of an automatic engine stop process.

[0093] The vehicle system controller 12 may also transmit vehicle suspension settings to the suspension controller 280. The suspension of the vehicle 121 (eg, 111) may be adjusted to severely damp, over damp, or under damp the vehicle suspension via the variable damper 281.

[0094] Thus, torque control of the various powertrain components may be governed by the vehicle system controller 12 (where local torque control of the engine 110 , transmission 125 , motor 120 , and brake 218 is provided via the engine controller 111B, motor controller 252 , transmission controller 254 , and brake controller 141 ).

[0095] As an example, the engine torque output may be controlled by controlling the throttle (e.g., 62B) opening and / or valve timing, valve lift, and valve lift and push of a turbocharged or supercharged engine, by adjusting a combination of spark timing, fuel pulse width, fuel pulse timing, and / or air charge. In the case of a diesel engine, the controller 12 may control the engine torque output by controlling a combination of fuel pulse width, fuel pulse timing, and air charge. In all cases, engine control may be performed cylinder by cylinder to control the engine torque output.

[0096] As is known in the art, motor controller 252 may control torque output and electrical power generation from motor 120 by regulating current flow into and out of the magnetic field and / or armature windings of motor 120 .

[0097] The transmission controller 254 may receive the transmission output shaft torque from the torque sensor 272. Alternatively, the sensor 272 may be a position sensor, or a torque and position sensor. In the case where the sensor 272 is a position sensor, the transmission controller 254 may count the shaft position pulses within a predetermined time interval to determine the transmission output shaft speed. The transmission controller 254 may also differentiate the transmission output shaft speed to determine the transmission output shaft acceleration. The transmission controller 254, the engine controller 111B, and the vehicle system controller 12 may also receive additional transmission information from the sensor 277, which may include but is not limited to a pump output line pressure sensor, a transmission hydraulic sensor (e.g., a gear clutch fluid pressure sensor), a motor temperature sensor, a BISG temperature sensor, a shift selector position sensor, a synchronizer position sensor, and an ambient temperature sensor. The transmission controller may also receive a requested transmission state (e.g., a requested gear mode or parking mode) from the shift selector 279, which may be a lever, a switch, or other device.

[0098] The brake controller 141 receives wheel speed information via the wheel speed sensor 195 and receives a brake request from the vehicle system controller 12. The brake controller 141 may also receive a brake request from Figure 1AThe brake pedal sensor (e.g., 157) shown receives brake pedal position information directly or via CAN 299. The brake controller 141 can provide braking in response to wheel torque commands from the vehicle system controller 12. The brake controller 141 can also provide anti-lock and vehicle stability braking to improve vehicle braking and stability. In this way, the brake controller 141 can provide a wheel torque limit (e.g., a threshold value that does not exceed negative wheel torque) to the vehicle system controller 12 so that negative motor torque does not cause the wheel torque limit to be exceeded. For example, if the controller 12 issues a negative wheel torque limit of 50N-m, the motor torque can be adjusted to provide a negative torque of less than 50N-m (e.g., 49N-m) at the wheel (including taking into account the transmission transmission).

[0099] Positive torque can be transmitted to the vehicle wheels 131 in a direction starting from the engine 110 and ending at the wheels 131. Therefore, the engine 110 is located upstream of the transmission 125 in the powertrain 200 according to the direction of the positive torque flow in the powertrain 200. The transmission 125 is located upstream of the motor 120, and the BISG 142a can be located upstream of the engine 110, or downstream of the engine 110 and upstream of the transmission 125.

[0100] Figure 3A A detailed illustration of a dual clutch transmission (DCT) 125 is shown. The engine crankshaft 40B is shown connected to the clutch housing 393. Optionally, a shaft can connect 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 may include a first clutch 126 and a second clutch 127. In addition, each of the first clutch 126 and the second clutch 127 has an associated first clutch plate 390 and a second clutch plate 391, respectively. In some examples, the clutch may include a wet clutch, a clutch immersed in oil (for cooling), or a dry plate clutch. The engine torque can be transmitted from the clutch housing 393 to the first clutch 126 or the second clutch 127. The first transmission clutch 126 is connected to the engine 110 ( Figure 1A ) and the first transmission input shaft 302. Therefore, the clutch housing 393 can be referred to as the input 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 is connected to the engine 110 ( Figure 1A 304). In this way, the clutch housing 393 can be referred to as the input side of the second transmission clutch 127, and 127A can be referred to as the output side of the second transmission clutch 127.

[0101] As described above, the gearbox 128 may include a plurality of gears. There are two transmission input shafts, including a first transmission input shaft 302 and a second transmission input shaft 304. The second transmission input shaft 304 is hollow, while the first transmission input shaft 302 is solid and coaxially located within the second transmission input shaft 304. As an example, the first transmission input shaft 302 may have a plurality of fixed gears. For example, the first transmission input shaft 302 may include a first fixed gear 306 for receiving a first gear 320, a third fixed gear 310 for receiving a third gear 324, a fifth fixed gear 314 for receiving a fifth gear 329, and a seventh fixed gear 318 for receiving a seventh gear 332. In other words, the first transmission input shaft 302 may be selectively connected to a plurality of odd-numbered gears. The second transmission input shaft 304 may include a second fixed gear 308 for receiving a second gear 322 or a reverse gear 328, and may also include a fourth fixed gear 316 for receiving a fourth gear 326 or a sixth gear 330. It will be appreciated that both the first transmission input shaft 302 and the second transmission input shaft 304 may be connected to each of the first clutch 126 and the second clutch 127, respectively, via ridges (not shown) on the outside of each shaft. In a normal stationary state, each of the first clutch 302 and the second clutch 304 is held open (e.g., via a spring (not shown) or the like) such that torque from an engine (e.g., 110) is not transferred to the first transmission input shaft 302 or the second transmission input shaft 304 when the respective clutch is in the open state. Engine torque may be transferred to the first transmission input shaft 302 in response to closing the first clutch 126, and engine torque may be transferred to the second transmission input shaft 304 in response to closing the second clutch 127. During normal operation, the transmission electronics may ensure that only one clutch is closed at any given time.

[0102] The gearbox 128 may also include a first countershaft shaft 340 and a second countershaft shaft 342. The gears on the first countershaft shaft 340 and the second countershaft shaft 342 are not fixed but can rotate freely. In the example DCT 125, the first countershaft shaft 340 includes a first gear 320, a second gear 322, a sixth gear 330, and a seventh gear 332. The second countershaft shaft 342 includes a third gear 324, a fourth gear 326, a fifth gear 329, and a reverse gear 328. Both the first countershaft shaft 340 and the second countershaft shaft 342 can transmit torque to gear 353 via a first output pinion 350 and a second output pinion 352, respectively. In this way, the two countershafts can transmit torque to the output shaft 362 via each of the first output pinion 350 and the second output pinion 350, where the output shaft can transmit torque to the rear drive unit 136 ( Figure 1AAs shown), the rear drive unit 136 can enable each driven wheel (eg Figure 1A 131) (for example, when performing a steering maneuver) rotates at different speeds.

[0103] As described above, each of 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 is not fixed to the secondary shaft (e.g., 340 and 342) but can rotate freely. In this way, a synchronizer can be used to enable each gear to match the speed of the secondary shaft, and the synchronizer can also be used to lock the gears. In the example DCT 125, four synchronizers are shown, such as the first synchronizer 370, the second synchronizer 374, the third synchronizer 380 and the fourth synchronizer 382. The first synchronizer 370 includes a corresponding first selector fork 372, the second synchronizer 374 includes a corresponding selector fork 376, the third synchronizer 380 includes a corresponding third selector fork 378, and the fourth synchronizer 384 includes a corresponding fourth selector fork 382. Each selector fork can enable each corresponding synchronizer movement to lock one or more gears or unlock one or more gears. For example, the first synchronizer 370 can be used to lock the first gear 320 or the seventh gear 332. The second synchronizer 374 can be used to lock the second gear 322 or the sixth gear 330. The third synchronizer 380 can be used to lock the third gear 324 or the fifth gear 329. The fourth synchronizer 384 can be used to lock the fifth gear 326 or the reverse gear 328. In each case, the movement of the synchronizer can be achieved by moving each corresponding synchronizer to a desired position through a selector fork (e.g., 372, 376, 378, and 382). Each of the synchronizers 370, 374, 380, and 384 includes a synchronizer tooth 358 to engage with the synchronizer tooth 359 of the gears 320, 332, 322, 330, 324, 329, 326, and 328. Each of the synchronizers 370, 374, 380, and 384 includes a synchronizer friction element 357, which equalizes the speed between each synchronizer and its corresponding gear. Therefore, the friction element 357 can transmit torque between the gear and the synchronizer to equalize the gear speed with the transmission shaft speed.

[0104] Movement of the synchronizer via the selector fork may be performed via a transmission control module (TCM) 254 and a shift fork actuator 388, wherein the TCM 254 may include the components described above with respect to Figure 2The TCM 254 discussed. The shift fork actuator can be operated electrically, hydraulically, or in combination electrically and hydraulically. The hydraulic power can be provided via pump 312 and / or pump 367. TCM 254 can collect input signals from various sensors, evaluate inputs, and control various actuators accordingly. The inputs used by TCM 254 may include, but are not limited to, transmission ranges (P / R / N / D / S / L (parking gear / reverse gear / neutral gear / forward gear / low gear / sports gear), etc.), vehicle speed, engine speed and torque, throttle position, engine temperature, ambient temperature, steering angle, brake input, gearbox input shaft speed (for the first transmission input shaft 302 and the second transmission input shaft 304), vehicle posture (tilt). TCM can control actuators via open-loop control to achieve adaptive control. For example, adaptive control can enable TCM 254 to identify and adapt to the position of the clutch engagement point, clutch friction coefficient, and synchronizer assembly. The TCM 254 can also regulate the first clutch actuator 389 and the second clutch actuator 387 to open and close the first clutch 126 and the second clutch 127. The first clutch actuator 389 and the second clutch actuator 387 can be operated electrically, hydraulically, or a combination of electrically and hydraulically. Hydraulic power can be provided via the pump 312 and / or the pump 367.

[0105] Such a TCM 254 is shown receiving inputs from various sensors 277. As described above with respect to Figure 2 As discussed above, the various sensors may include a pump output line pressure sensor, a transmission hydraulic pressure sensor (e.g., a gear clutch fluid pressure sensor), a motor temperature sensor, a shifter position sensor, a synchronizer position sensor, and an ambient temperature sensor. The various sensors 277 may further include a wheel speed sensor (e.g., 195), an engine speed sensor, an engine torque sensor, a throttle position sensor, an engine temperature sensor, a steering angle sensor, and an inertial sensor (e.g., 199). As discussed above with respect to Figure 1A As discussed, the inertial sensors may include one or more of the following: longitudinal, lateral, vertical, yaw, roll, and pitch sensors.

[0106] The sensors 277 may also include an input shaft speed (ISS) sensor, which may include a reluctance sensor, and wherein one ISS sensor may be included for each gearbox input shaft (e.g., one ISS sensor for the first transmission input shaft 302 and one ISS sensor for the second transmission input shaft 304). The sensors 277 may also include an output shaft speed sensor (OSS), which may include a reluctance sensor and may be attached to the output shaft 362. The sensors 277 may also include a transmission range (TR) sensor and a fork position sensor to detect the position of the selector forks (e.g., 372, 376, 378, 382).

[0107] It is understood that the DCT 125 functions as described herein. For example, when the first clutch 126 is actuated closed, engine torque can be supplied to the first transmission input shaft 302. When the first clutch 126 is closed, it is understood that the second clutch 127 is open, and vice versa. Power can be transmitted to the first countershaft 340 or the second countershaft 342 via the first transmission input shaft 302, depending on the gear that is locked when the first clutch 126 is closed, and can also be transmitted to the output shaft 362 via the first pinion 350 or the second pinion 352. Alternatively, when the second clutch 127 is closed, power can be transmitted to the first countershaft 340 or the second countershaft 342 via the second transmission input shaft 304, depending on the gear that is locked, and can also be transmitted to the output shaft 362 via the first pinion 350 or the second pinion 352. It will be appreciated that when torque is being transferred to one countershaft (e.g., the first output shaft 340), the other countershaft (e.g., the second output shaft 342) may continue to rotate even though only one shaft is directly driven by the input. More specifically, the non-engaged shaft (e.g., the second countershaft 342) may continue to rotate due to being indirectly driven by the output shaft 362 and the corresponding pinion (e.g., 352).

[0108] The DCT 125 can enable pre-selection of gears, which can therefore enable fast switching between gears with minimal torque loss during gear shifting. As an example, when the first gear 320 is locked via the first synchronizer 370 and the first clutch 126 is closed (and the second clutch 127 is open), power can be transferred from the engine to the first input shaft 302 and to the first countershaft 340. When the first gear 320 is engaged, the second gear 322 can be locked via the second synchronizer 374 at the same time. Because the second gear 322 is locked, this can cause the second input shaft 304 to rotate, where the second input shaft 304 matches the vehicle speed in the second gear. In the alternative case where a gear is pre-selected on another countershaft (e.g., the second countershaft 342), the countershaft will also rotate due to the drive of the output shaft 362 and the pinion 352.

[0109] When a gear shift is initiated by TCM 254, only the clutches need to be actuated to open the first clutch 126 and close the second clutch 127. In addition, outside the TCM, the engine speed can be reduced to match the upshift. With the second clutch 127 closed, power can be transferred from the engine to the second input shaft 304 and to the first countershaft 340, and can also be transferred to the output shaft 362 via the pinion 350. After the gear shift is completed, TCM 254 can pre-select the next gear appropriately. For example, TCM 254 can pre-select a higher gear gear or a lower gear gear based on inputs received from various sensors 277. In this way, gear changes can be quickly achieved with minimal loss of engine torque supplied to the output shaft 362.

[0110] The dual clutch transmission 300 may include a parking gear 360 in some examples. The parking pawl 363 may face the parking gear 360. When the shift lever is set to parking, the parking pawl 363 may engage the parking gear 360. The engagement of the parking pawl 363 with the parking gear 360 may be achieved via a parking pawl spring 364, or may be achieved, for example, via a cable (not shown), a hydraulic piston (not shown) or a motor (not shown). When the parking pawl 363 is engaged with the parking gear 360, the drive wheels (e.g., 130, 131) of the vehicle may be locked. On the other hand, the parking pawl 363 may move in response to the shift lever moving from the parking position to another selection (e.g., the driving position) so that the parking pawl 363 may be separated from the parking gear 360.

[0111] In some examples, the electric transmission pump 312 can supply hydraulic fluid from the transmission tank 311 to compress the spring 364 to release the parking pawl 363 from the parking gear 360. For example, the electric transmission pump 312 can be powered by an onboard energy storage device (e.g., 132). In some examples, the mechanical pump 367 can additionally or alternatively supply hydraulic fluid from the transmission tank 311 to compress the spring 364 to release the parking pawl 363 from the parking gear 360. Although not explicitly shown, the mechanical pump can be driven by an engine (e.g., 110) and can be mechanically connected to the clutch housing 393. In some examples, the parking pawl valve 361 can regulate the flow of hydraulic fluid to the spring 364.

[0112] Reference now Figure 3B , shows an example of a second type of transmission that may be included in drive train 200. In this example, a transmission having a planetary gear set is shown.

[0113] The torque converter 371 can receive input torque from the ISG 142 or the engine 110, and the torque converter clutch 373 can selectively lock the torque converter pump wheel (not shown) to the torque converter turbine (not shown). The torque can be transmitted from the torque converter 371 to the input shaft 301. The input shaft 301 is drivably connected to the sun gear 303 of the planetary gear unit or the epicyclic gear unit. The gear carrier 305 of the gear unit is drivably connected to the output shaft 307 that drives the vehicle wheels.

[0114] The gear unit includes a ring gear 309 surrounding the sun gear 303 and a first set of planetary pinions 313 rotatably supported on the gear carrier 305, the first set of planetary pinions 313 continuously meshing with the sun gear 303 and the ring gear 309. A planetary pinion set 315 is fixed to each pinion constituting the pinion set 313, the planetary pinion set 315 is rotatably supported on the gear carrier 305, the planetary pinion set 315 continuously meshes with the second sun gear 317 and meshes with each planetary pinion constituting the third set of pinion gears 319, the third set of pinion gears 319 also being rotatably supported on the gear carrier 305. A second ring gear (not shown) surrounds the sun gear 317 and the planetary pinion sets 315, 319, the second ring gear meshing with each pinion of the set 319.

[0115] The fourth set of planetary pinion gears 321 axially extends from and is fixed to each of the planetary pinion gears constituting the pinion gear set 315, and is rotatably supported on the gear carrier 305 and continuously meshes with the third sun gear 323. Each member of the planetary pinion gear set 321 continuously meshes with members of the fifth and sixth planetary pinion gear sets 325, 327, respectively, which are also rotatably supported on the gear carrier 305. Each member of the planetary pinion gear set 325 continuously meshes with the third ring gear 331; each member of the planetary pinion gear set 327 continuously meshes with the fourth ring gear 333.

[0116] The third sun gear 323 is drivably connected to a fourth speed brake drum 337 by means of a member 335, the outer surface of which has substantially the same radius as the outer surfaces of the ring gears 309, 331 and 333. Similarly, the second sun gear 317 is drivably connected to a fifth speed brake drum 343 by means of a member 341, the outer surface of which has substantially the same radius as the outer surfaces of the ring gear and the brake drum 337. The outer surfaces of the brake drums 337, 343 and the ring gears 345, 309, 331 and 333 are adjacent to each other, aligned and located in a substantially cylindrical surface.

[0117] The first and second brake bands 347 and 349 are axially displaced. The first and second brake bands are alternately actuated to engage and release the ring gears 345, 309, 331, 333 and the brake drums 337, 343. When the ring gears and brake drums are engaged by the brake bands, the ring gears and brake drums are held fixed to prevent rotation because the guide rails supporting the ring gears and brake drums are held fixed to the transmission case to prevent rotation. First gear is produced when the ring gear 345 is held; second and third gears are produced when the ring gears 331 and 333 are held, respectively; fourth and fifth gears are produced when the sun gears 323 and 317 are held, respectively; and reverse gear is produced when the ring gear 309 is held. The brake bands 347 and 349 can be selectively applied and released via hydraulic servos 351 and 355, which can be controlled via the transmission controller 254.

[0118] therefore, Figures 1A-3B A system is provided, comprising: a first motor; a transmission, the transmission selectively mechanically connected to the first motor via an input clutch; a second motor included in a rear drive unit, the rear drive unit mechanically connected to an output shaft of the transmission; and a controller, the controller including executable instructions stored in a non-temporary memory to operate the second motor in a speed control mode and simultaneously change the output torque of the first motor while the input clutch and the gear clutch of the transmission are closed, and instructions to operate the transmission in response to currents supplied to the first motor and the second motor immediately before the output torque of the first motor is changed, and currents supplied to the first motor and the second motor immediately after the output torque of the first motor is changed.

[0119] In some examples, the system further includes operating the transmission with a closed input clutch and a closed gear clutch. The system further includes estimating the transmission torque ratio in response to the current supplied to the first motor and the second motor just before the output torque of the first motor is about to be changed and the current supplied to the first motor and the second motor immediately after the output torque of the first motor is changed. The system includes wherein the instruction to operate the transmission in response to the current includes changing the transmission gear. The system includes wherein operating the second motor in the speed control mode includes maintaining a constant vehicle speed. The system also includes estimating the transmission efficiency based on the current supplied to the first motor and the second motor just before the output torque of the first motor is about to be changed and the current supplied to the first motor and the second motor immediately after the output torque of the first motor is changed.

[0120] Reference now Figure 4 , a first example method for operating a hybrid powertrain to determine transmission control parameters is shown. Figure 4 The method can be used with Figure 6 and Figure 8In addition, Figure 4 The method can be incorporated into Figures 1A-3B system and can be used with Figures 1A-3B In addition, Figure 4 At least some portions of the method may be incorporated as executable instructions stored in a non-transitory memory, while other portions of the method may be performed via a controller that transforms the operating states of devices and actuators in the physical world.

[0121] At 402, method 400 determines whether transmission output torque characterization is required. Transmission output torque characterization may be required after the transmission-operated vehicle has been driven a predetermined distance or amount of time. If method 400 determines that transmission output torque characterization is required, the result is yes and method 400 proceeds to 404. Otherwise, the result is no and method 400 proceeds to 450.

[0122] At 450, method 400 operates the transmission with the latest transmission output torque characterizing value. For example, if the vehicle has just left the manufacturing plant, the transmission will operate according to the factory installed values ​​describing the transmission function of the torque ratios of the various transmission gears. Method 400 continues to exit.

[0123] At 404, method 400 determines whether the driver demand vehicle acceleration is less than a (LT) threshold. In one example, the driver demand vehicle acceleration may be determined via an accelerator pedal position and vehicle speed index or reference to a table or function of empirically determined vehicle acceleration values. If method 400 determines that the driver demand vehicle acceleration is less than a threshold, the result is yes and method 400 proceeds to 406. Otherwise, the result is no and method 400 proceeds to 450.

[0124] At 406, method 400 determines whether at least one transmission input shaft is mechanically connected to the ISG or the engine crankshaft. In addition, if the transmission includes a disconnect clutch and the transmission will be driven by the BISG, the method may require the transmission disconnect clutch to be fully closed. If method 400 determines that at least one transmission input shaft is mechanically connected to the engine crankshaft, the result is yes and method 400 proceeds to 408. Alternatively, if at least one transmission input shaft is mechanically connected to the ISG and the ISG is driving the transmission, the result is yes and method 400 proceeds to 408. Otherwise, the result is no and method 400 proceeds to 450. In addition, if the hybrid powertrain includes a planetary gear set, method 400 may require the torque converter clutch to be fully closed to mechanically connect the engine crankshaft to the transmission input shaft. Method 400 may also require that one or more gear clutches be closed and the gears be fully engaged before proceeding to 408.

[0125] At 408, method 400 operates a motor included in the rear drive unit in a speed control mode having a reference speed or a desired speed thereof according to the driver demand acceleration. The motor follows the reference speed when operating in the speed control mode. The torque of the motor can be increased or decreased so that the speed of the motor follows the reference speed. The torque of the motor can be increased by increasing the current supplied to the motor. The torque of the motor can be reduced by reducing the current supplied to the motor. When the driver demand acceleration is zero, the reference speed can be a constant speed. In one example, the reference speed can be determined via a function or table including an empirically determined vehicle acceleration value, which is a function of the driver demand vehicle acceleration. The motor included in the rear drive unit or the rear drive unit motor is commanded to the reference speed in the speed control mode. Method 400 proceeds to 410.

[0126] At 410, method 400 stores the current ISG, BISG and rear drive unit motor torques to the controller memory. The ISG motor torque can be estimated in response to the current supplied to the ISG and the ISG speed. In one example, the ISG speed and current index or reference outputs a function of the ISG torque value determined empirically. The BISG torque and rear drive unit motor torque can be determined in a similar manner. After the motor torque is stored in the memory and the torque of the ISG, BISG and rear drive unit motor is not further adjusted, the method 400 commands an increase or decrease in the ISG or BISG torque. Then the method 400 determines the amount of the ISG, BISG and rear drive unit motor torque values ​​immediately after the powertrain operating conditions have stabilized after the torque increase or decrease has been performed, and determines the ISG, BISG and rear drive unit motor torques in response to or according to the motor currents of the ISG, BISG and rear drive unit.

[0127] The increase or decrease of the ISG or BISG torque can be limited to a value less than the amount that the rear drive unit motor can compensate. For example, if the transmission engaged in the current gear has a 4 to 1 ratio, the rear drive unit motor has a torque output capacity of 200N-m, and the rear drive unit motor currently outputs 100N-m, the ISG or BISG torque can be reduced by a maximum of 25N-m, so that the rear drive unit motor can provide the torque previously provided by the ISG or BISG to the transmission input, so that the vehicle acceleration can be maintained at the vehicle acceleration required by the driver. In other words, the ISG or BISG torque reduction is transmitted to the transmission output shaft as a torque reduction of 100N-m, and the torque loss can be compensated by increasing the rear drive unit motor torque output to the rear drive unit, so that the rear drive unit provides a maximum torque of 200N-m. Conversely, if the ISG or BISG torque increases, the rear drive unit motor torque can be reduced in a similar manner to maintain the vehicle acceleration at the vehicle acceleration required by the driver.

[0128] At 412, method 400 determines the change in rear drive unit motor torque output to maintain the desired driver demand vehicle acceleration. Since the rear drive unit motor is in speed control mode, the rear drive unit motor torque changes in response to the ISG or BISG torque adjustment to maintain the driver demand vehicle acceleration. The change in rear drive unit motor torque can be determined by subtracting the rear drive unit motor torque output immediately before the ISG or BISG torque change from the rear drive unit motor torque output immediately after the ISG or BISG torque change, and taking the absolute value of the result. For example, if the rear drive unit motor output torque is 100 N-m before the ISG or BISG torque change, and the rear drive unit motor torque is 200 N-m after the ISG or BISG torque change, the rear drive unit torque change is 100 N-m.

[0129] Method 400 may also determine the torque change of the ISG or BISG by subtracting the ISG or BISG torque output immediately before the ISG or BISG torque change from the ISG or BISG torque immediately after the ISG or BISG torque change and taking the absolute value of the result. For example, if the ISG or BISG torque is 50 N-m before the ISG or BISG torque change and is 25 N-m after the ISG or BISG torque change, the ISG or BISG torque change is 25 N-m. Method 400 proceeds to 414.

[0130] At 414, method 400 determines the current transmission torque ratio of the currently engaged transmission gear. Transmission shifting is not allowed when the transmission output torque is characterized, but alternatively, if a transmission shift is requested when method 400 is activated, method 400 can exit. In one example, method 400 determines the transmission torque ratio of the current gear by dividing the change in transmission output torque (which is equal to the change in rear drive unit motor torque determined at 412) by the change in transmission input torque (which is equal to the change in ISG or BISG torque determined at 412). For example, if the rear drive unit motor torque changes by 100 N-m and the ISG or BISG torque changes by 25 N-m, the transmission torque ratio is four. Transmission efficiency can be estimated by dividing the rear drive unit motor torque after ISG or BISG torque adjustment by the ISG or BISG torque after ISG or BISG torque adjustment and then dividing by the gear ratio of the currently engaged gear. Method 400 proceeds to 416.

[0131] At 416, method 400 modifies the values ​​of transmission torque ratio and transmission efficiency stored in the controller memory using the values ​​determined at 414. In addition, method 400 adjusts the transmission shift according to the modified transmission torque ratio. In one example, method 400 adjusts the transmission input torque during the shift according to the following equation:

[0132]

[0133] Among them, Tq Trn_inst_max is the maximum instantaneous torque limit of the transmission input, Tq Trn_in_newgear is the transmission input torque in the new gear immediately after the oncoming clutch is fully closed, RT gear_new is the torque ratio of the transmission when engaging a new gear (e.g., adaptation value), RT gear_old is the torque ratio of the transmission when engaging the original gear (e.g., and the adaptation value), Tq Trn_in_oldgear is the transmission input torque in the original gear immediately before the disengaging clutch begins to release during the current gear change, J Trn_in is the effective input inertia of the transmission, ω Trn_out is the transmission output shaft angular velocity, and T shft_dur is the duration of the shift or gear ratio change. In addition, the engine torque and the ISG torque may be adjusted to provide a desired wheel torque that compensates for transmission efficiency. Method 400 continues to exit after operating the transmission with the adjusted control parameters.

[0134] In this way, the adapted transmission control parameters can be used to adjust the transmission input torque during the transmission shift. These adjustments can improve the shift consistency and shift feel. In addition, the adjustment of ISG torque and engine torque for transmission efficiency can provide improved wheel torque output.

[0135] Reference now Figure 5 , which shows that according to Figure 4 A method for predicting transmission output torque characterization sequence. Figure 5 The sequence can be combined Figures 1A-3B The system operates Figure 4 method to provide. Figure 5 The data in the graphs of occur simultaneously and the graphs are aligned in time. The vertical markers at times T0-T6 indicate the times of interest in the sequence.

[0136] from Figure 5 The first graph starting from the top of FIG. 50 is a graph of the transmission torque characterizing state versus time. The transmission torque characterizing state is active when the trace 502 is at a higher level near the vertical axis arrow. The transmission torque characterizing state is inactive when the trace 502 is at a lower level near the vertical axis arrow. The horizontal axis represents time and time increases from the left side of the graph to the right side of the graph.

[0137] from Figure 5 The second graph from the top of is a graph of driver demand torque versus time. The vertical axis represents the driver demand torque, and the driver demand torque increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0138] from Figure 5 The third graph from the top of is a graph of rear drive unit motor torque versus time. The vertical axis represents rear drive unit motor torque, and the rear drive unit motor torque increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0139] from Figure 5 The fourth graph from the top of is a graph of ISG or BISG torque versus time. The vertical axis represents ISG or BISG torque, and the ISG or BISG torque increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0140] At time T0, the transmission torque characterizing state is not asserted, so the transmission torque ratio and efficiency are not required to be determined and modified. The driver demand torque is constant, so the required vehicle acceleration is zero. The rear drive unit motor torque is a constant intermediate level, and the ISG or BISG torque is zero.

[0141] At time T1, the transmission torque characterizing state changes from a low value to a high value to request characterizing transmission torque and efficiency. The driver demand torque, rear drive unit motor torque, and BISG or ISG torque values ​​remain at their previous levels.

[0142] Between time T1 and time T2, the ISG or BISG torque is determined by the ISG or BISG current, and the rear drive unit motor torque is determined by the rear drive unit motor current (not shown). Both torque values ​​are stored in memory. The driver demand torque remains constant, the rear drive unit motor torque remains constant, and the ISG or BISG torque remains constant. The transmission torque characterization state remains valid.

[0143] At time T2, the ISG or BISG torque output increases in a step-like manner. The rear drive unit motor torque decreases in a step-like manner in response to the increase in the ISG or BISG torque. The vehicle speed can be maintained substantially constant (e.g., changes by less than 5%) by reducing the rear drive unit motor torque in response to the increase in the ISG or BISG torque. The transmission torque characterization state remains valid and the driver demand torque remains constant.

[0144] Between time T2 and time T3, the ISG or BISG torque is determined by the ISG or BISG current, and the rear drive unit motor torque is determined by the rear drive unit motor current (not shown). Both torque values ​​are stored in memory. The driver demand torque remains constant, the rear drive unit motor torque remains constant, and the ISG or BISG torque remains constant. The transmission torque characterization state remains valid. Once the ISG or BISG torque value and the rear drive unit motor torque value are determined, the transmission torque ratio and transmission efficiency are as follows Figure 4 The determination is described at 414 and stored in the controller memory.

[0145] At time T3, the ISG or BISG torque output is reduced in a step-like manner. The rear drive unit motor torque is increased in a step-like manner in response to the reduction in the ISG or BISG torque. The vehicle speed can be maintained substantially constant (e.g., a change of less than 5%) by increasing the rear drive unit motor torque in response to the reduction in the ISG or BISG torque. The ISG or BISG torque becomes zero. The transmission torque characterization state remains valid and the driver demand torque remains constant.

[0146] Between time T3 and time T4, the ISG or BISG torque remains constant as does the driver demand torque and the rear drive unit motor torque. The transmission torque characteristic state remains valid.

[0147] At time T4, the ISG or BISG torque increases in a ramp-like manner and the rear drive unit motor torque decreases in a ramp-like manner to offset the ISG torque increase and maintain vehicle speed. The driver demand torque remains constant and the transmission torque characterizing state remains valid.

[0148] Between time T4 and time T5, whenever the ISG or BISG torque increases, the ISG or BISG torque is determined by the ISG or BISG current, and whenever the ISG or BISG torque increases, the rear drive unit motor torque is determined by the rear drive unit motor current (not shown). Both torque values ​​are stored in memory. The driver demand torque remains constant, the rear drive unit motor torque remains constant, and the ISG or BISG torque remains constant. The transmission torque characterization state remains valid. Whenever the ISG or BISG torque and rear drive unit motor torque values ​​are determined, as shown Figure 4 The transmission torque ratio and transmission efficiency are determined as described at 414. The transmission torque ratio and transmission efficiency may be averaged and stored to the controller memory as an alternative to the method described from T1 to T2.

[0149] At time T5, the BISG or ISG torque is reduced to zero and the rear drive unit motor torque returns to its value just before time T4. The driver demand torque remains constant and the transmission torque characterizing state remains valid.

[0150] At time T6, the transmission torque characterization state transitions to a low state to indicate that transmission torque characterization is not being performed. The driver demand torque remains constant, and the rear drive unit motor torque and the ISG or BISG torque remain at their previous values.

[0151] In this manner, transmission torque ratio characterization and efficiency characterization may be performed in a manner that reduces the likelihood of disturbing vehicle occupants. Additionally, characterization may be determined after a step response, a ramp response, or after the ISG or BISG torque is held constant (not shown).

[0152] Reference now Figure 6 , which shows a second example method for operating a hybrid powertrain to determine transmission control parameters. Figure 6 Methods to collaborate Figure 4 and Figure 8 In addition, Figure 6 The method can be incorporated into Figures 1A-3B system and can be used with Figures 1A-3B In addition, Figure 6At least some portions of the method may be incorporated as executable instructions stored in a non-transitory memory, while other portions of the method may be performed via a controller that transforms operating states of devices and actuators in the physical world.

[0153] At 602 , method 600 judges whether a transmission input clutch (eg, Figure 3A 126 or 127) characterization. Transmission input clutch characterization may be desired after the transmission-operated vehicle has been driven a predetermined distance or amount of time or in response to the actual total number of gear changes since the vehicle was manufactured. If method 600 determines that transmission input clutch characterization is desired, the result is yes and method 600 proceeds to 604. Otherwise, the result is no and method 600 proceeds to 650.

[0154] At 650, method 600 operates the transmission with the most recent transmission input clutch torque characterizing value. For example, if the vehicle has just left the manufacturing plant, the transmission operates with the factory installed value for the transmission function describing the transmission input clutch operation. Method 600 continues to exit.

[0155] At 604, method 600 determines whether the transmission input clutch is open and the transmission is locked in gear (e.g., a synchronizer has locked the gear to the transmission shaft). In one example, the transmission input clutch can be determined to be open and the gear is locked in response to an actuator sensor in the transmission. By locking the transmission in gear, torque can be transferred to the engine and ISG or BISG when the input clutch is at least partially closed, or from the engine and ISG or BISG to the wheels, so that torque can be transferred through the transmission input clutch. If method 600 determines that the transmission input clutch is open and the transmission is locked in gear, the result is yes and method 600 proceeds to 606. Otherwise, the result is no and method 600 proceeds to 650.

[0156] At 606, method 600 determines whether the engine torque is low enough to allow the ISG or BISG torque to control the engine speed in the speed control mode. In one example, method 600 may determine that the engine torque is low enough to control the engine speed via the ISG or BISG when the engine torque is less than a threshold torque. If method 600 determines that the engine torque is low enough to allow the ISG or BISG torque to control the engine speed in the speed control mode, the result is yes and method 600 proceeds to 608. Otherwise, the result is no and method 600 proceeds to 650.

[0157] At 608, method 600 operates the ISG or BISG in a speed control mode with its reference speed according to the driver demand acceleration. In addition, the engine is commanded to a constant torque in a torque control mode. In the torque control mode, the speed of the engine is allowed to change while the engine torque is controlled to a reference value (e.g., a constant). Therefore, if the load on the engine is reduced and the engine outputs a constant torque value, the engine can increase from a speed of 1000RPM (revolutions per minute) to a speed of 1200RPM. By commanding the ISG or BISG to reach a constant speed and the engine to reach a constant torque, the engine and ISG or BISG speeds can be kept constant.

[0158] In addition, method 600 may command the rear drive unit motor to be a reference speed (e.g., a constant speed) in a speed control mode, the reference speed of the rear drive unit being different from the reference speed of the ISG or BISG, and the reference speed of the rear drive unit being not a transmission gear ratio multiple of the ISG reference speed. The reference speed of the rear drive unit may be greater than or less than the ISG reference speed. By operating the ISG or BISG at a speed different from that of the rear drive unit motor, a closed transmission input clutch may transfer torque from the ISG or BISG to the rear drive unit motor or vice versa, so that the torque transmitted by the transmission input clutch may be determined. Alternatively, the transmission may be set in a parking gear with the gear engaged to resist the torque transmitted via the transmission input clutch. In other examples, the output shaft of the transmission may be locked in a fixed position by applying the vehicle brake when locking the gear, so that the torque transmitted by the transmission input clutch is grounded. Method 600 determines the ISG or BISG torque after the ISG or BISG enters the speed control mode and stores the torque value in a memory. Method 600 proceeds to 610.

[0159] At 610, method 600 applies a predetermined amount to the transmission input clutch. In one example, the position of the transmission input clutch is adjusted in response to a desired transmission input clutch torque (e.g., the amount of torque that the clutch can transmit at a given clutch position). The desired transmission input clutch torque can be based on a shift profile or transfer function stored in a non-transient memory of the controller (e.g., a table or function that associates the transmission input clutch position with the amount of torque that can be transmitted via the transmission input clutch), and the transmission input clutch can be adjusted to a suitable position in response to the transfer function that associates the desired transmission input clutch torque with the transmission input clutch position. For example, a table or function stored in a non-transient or temporary memory can maintain the position of the transmission input clutch, and the table or function can output the transmission input clutch position in response to the desired transmission input clutch torque that references or indexes the table or function. The table or function can store multiple transmission input clutch positions that can be individually referenced by different desired transmission input clutch torque values. The transmission input clutch can be adjusted to each transmission clutch position in the table or function to correct and / or verify that the transmission input clutch is transmitting the amount of torque corresponding to each transmission input clutch position in the table or function. Method 600 commands the transmission input clutch to a position in a table or function and then proceeds to 612 .

[0160] At 612, method 600 determines the amount of torque transmitted to the transmission output shaft via the transmission input clutch. In one example, method 600 determines the change in ISG or BISG torque by subtracting the ISG or BISG torque at the time immediately before closing the transmission input clutch from the ISG or BISG torque immediately after closing the transmission input clutch to a position that should provide the desired transmission input clutch torque and the transmission input clutch position is stable (e.g., a change of less than 5%). The ISG or BISG torque before the transmission input clutch is closed and after the transmission input clutch is closed can be determined in response to the ISG or BISG current. For example, a current of 0.5 amps may correspond to an ISG or BISG torque of 10 N-m. The method determines the change in ISG or BISG current by subtracting the ISG or BISG current before closing the transmission input clutch from the ISG or BISG current after closing the transmission input clutch. The change in ISG or BISG torque is the amount of torque transmitted by the transmission input clutch. If the amount of torque transmitted by the transmission input clutch determined based on the ISG or BISG current is not equal to the torque value in a table or function (e.g., a transmission input clutch transfer function), the value in the table corresponding to the current position of the transmission input clutch will be modified with the torque determined based on the ISG or BISG current. For example, if the transmission input clutch is closed to a position six millimeters from a fully open transmission input clutch position, which should have a transmission input clutch torque value of 40 N-m, but the ISG torque or BISG torque determined based on the ISG or BISG current indicates that the torque transmitted via the transmission input clutch is 35 N-m, then the table or function in the memory updates the six millimeter position in the table or function with a value of 35 N-m. After the transmission input clutch is applied to the specified position, method 600 proceeds to 614.

[0161] At 614, method 600 determines whether all values ​​in a function or table describing the operation of the transmission input clutch (e.g., a transmission input clutch transfer function) have been calibrated or verified. For example, if the function or table includes ten pairs of values ​​describing the operation of the transmission input clutch, and nine pairs of values ​​have been calibrated or verified, then the result is no, and method 600 proceeds to 620. However, if ten pairs of values ​​have been calibrated or verified, then the result is yes, and method 600 proceeds to 616.

[0162] At 620, method 600 adjusts the position of the transmission input clutch to a new position, which may be a position included in a table or function describing the transmission input clutch torque in response to the transmission input clutch position. For example, if the function or table includes a transmission input clutch position of 5 mm and a position of 7 mm, and the transmission input clutch has moved to the 5 mm position, the transmission input clutch moves to the 7 mm position. Method 600 returns to 612.

[0163] It should be mentioned that if vehicle operating conditions cause method 600 to exit without all positions in a table or function describing transmission input clutch operation being adapted, adjusted, or verified, method 600 may later restore the adapted values ​​in the table or function starting from the previously unadjusted or verified values ​​in the table or function.

[0164] At 616, method 600 operates the transmission input clutch according to a table or function describing the operation of the transmission input clutch, including any values ​​that may have been adjusted. For example, if the transmission input clutch is expected to transmit 200 N-m of torque, the transmission input clutch is adjusted to a position corresponding to the transmission input clutch being able to transmit 200 N-m of torque. Method 600 continues to exit.

[0165] In this way, the operation and control of the transmission input clutch can be adjusted, and the values ​​in the table or function describing the transmission input clutch can be revised as the vehicle and the transmission input clutch age. Each transmission input clutch can have a separate function or table describing its operation, and method 600 can be the basis for adjusting the function or table for each transmission input clutch.

[0166] Reference now Figure 7 , which shows that according to Figure 6 The method predicts the transmission output torque characterization sequence. It can be combined with Figures 1A-3B System operation Figure 6 The method provides Figure 7 sequence. Figure 7 The data in the graphs of occur simultaneously and the graphs are aligned in time. The vertical markers at times T10-T16 indicate times of interest in the sequence.

[0167] from Figure 7 The first graph starting from the top of FIG. 702 is a graph of the transmission input clutch representative state versus time. When the trace 702 is at a higher level near the vertical axis arrow, the transmission input clutch representative state is activated. When the trace 702 is at a lower level near the vertical axis arrow, the transmission input clutch representative state is inactivated. The horizontal axis represents time and time increases from the left side of the graph to the right side of the graph.

[0168] from Figure 7 The second graph from the top of is a graph of driver demand torque versus time. The vertical axis represents the driver demand torque, and the driver demand torque increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0169] from Figure 7 The third graph from the top of is a graph of rear drive unit motor torque versus time. The vertical axis represents rear drive unit motor torque, and the rear drive unit motor torque increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0170] from Figure 7 The fourth graph from the top of is a graph of ISG or BISG torque versus time. The vertical axis represents the ISG or BISG torque, and the ISG or BISG torque increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0171] from Figure 7 The fifth graph from the top of FIG. 1 is a graph of transmission input clutch torque (e.g., the amount of torque that the transmission input clutch can transmit as currently applied) versus time. The vertical axis represents the transmission input clutch torque, and the transmission input clutch torque increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0172] At time T10, the transmission input clutch torque characterizing state is not recognized, so there is no need to determine and correct the transmission input clutch positioning. The driver demand torque is constant. The motor torque of the rear drive unit is a constant intermediate level, and the ISG or BISG torque is a lower level. The transmission input clutch torque of zero indicates that the transmission input clutch is fully open.

[0173] At time T11, the transmission input clutch torque characterizing state changes from a low value to a high value to request a characterizing transmission input clutch torque. The driver demand torque, rear drive unit motor torque, and BISG or ISG torque values ​​remain at their previous levels. Additionally, the transmission input clutch torque remains at zero. The ISG or BISG is set in speed control mode as is the rear drive unit motor (not shown).

[0174] Between time T11 and time T12, the ISG or BISG torque is determined by the ISG or BISG current, and the rear drive unit motor torque is determined by the rear drive unit motor current (not shown). Both torque values ​​are stored in memory. The driver demand torque remains constant, the rear drive unit motor torque remains constant, and the ISG or BISG torque remains constant. The transmission input clutch torque characterization state remains valid.

[0175] At time T12, the transmission input clutch torque is increased in a stepwise manner by at least partially closing the transmission input clutch so that the transmission input clutch begins to transfer torque. The ISG or BISG torque is increased to maintain the ISG or BISG speed and the engine speed. In this example, the transmission input shaft speed is less than the ISG or BISG speed. The rear drive unit motor torque is reduced in a stepwise manner in response to the torque transmitted from the ISG or BISG to the transmission. The vehicle speed can be kept substantially constant (e.g., a change of less than 5%) by reducing the rear drive unit motor torque in response to the transmission input clutch torque. The transmission input clutch torque characterization state remains valid and the driver demand torque remains constant. The BISG or ISG torque change is compared to the commanded input clutch torque change, and if there is a difference, the table or function describing the transmission input clutch operation will be corrected with the torque determined by the BISG or ISG (not shown).

[0176] At time T13, the transmission input clutch torque is increased a second time in a step-wise manner. The rear drive unit motor torque is reduced in a step-wise manner in response to the increase in the transmission input clutch torque, which increases the torque input to the transmission. In addition, the ISG or BISG torque is increased in a step-wise manner to maintain the engine and ISG or BISG speeds. The vehicle speed can be kept substantially constant (e.g., a change of less than 5%) by reducing the rear drive unit motor torque in response to the increase in the transmission input clutch torque. The transmission input clutch torque characterization state remains valid and the driver demand torque remains constant.

[0177] At time T14, the transmission input clutch torque is reduced to zero in a step-like manner, and the BISG or ISG torque is reduced in response to the transmission input clutch torque reduction, so that the engine and ISG speeds can be maintained. The driver demand torque remains constant, and the transmission input clutch torque characterizing state remains valid. The rear drive unit motor torque is also increased in response to the reduction in the transmission input clutch torque, so that the vehicle speed can be maintained.

[0178] At time T15, the transmission input clutch torque characterization state transitions to a low state to indicate that the transmission input clutch torque characterization is not being performed. The driver demand torque remains constant, and the rear drive unit motor torque and ISG or BISG torque remain at their previous values. The transmission input clutch torque value also remains at zero.

[0179] In this way, the transmission input clutch operation can be characterized and the transfer function describing the transmission input clutch operation can be adjusted or tuned. The transmission input clutch transfer function can be adjusted as the vehicle ages so that the vehicle consistently shifts over time.

[0180] Reference now Figure 8 , which shows a third example method for operating a hybrid powertrain to determine transmission control parameters. Figure 8 The method can be used with Figure 4 and 6 In addition, Figure 8 The method can be incorporated into Figures 1A-3B system and can be used with Figures 1A-3B In addition, Figure 8 At least portions of the method may be incorporated as executable instructions stored in a non-transitory memory, while other portions of the method may be executed via a controller that transforms the operating states of devices and actuators in the physical world.

[0181] At 802, method 800 determines whether transmission shift element (e.g., synchronizer friction elements, synchronizer teeth, gear synchro teeth, and brake band) characterization is desired. Transmission shift element characterization may be desired after the transmission-operated vehicle has been driven a predetermined distance or amount of time or in response to the actual total number of gear changes since the vehicle was manufactured. If method 800 determines that transmission input clutch characterization is desired, the result is yes, and method 800 proceeds to 804. Otherwise, the result is no, and method 800 proceeds to 850.

[0182] At 850, method 400 operates the transmission with the latest transmission shift element torque characterizing values. For example, if the vehicle has just left the manufacturing plant, the transmission operates with factory installed values ​​of the transfer function describing the torque transfer of the transmission shift elements. Method 800 continues to exit.

[0183] At 804, method 800 determines whether the transmission input clutch is open and the transmission output shaft is locked. In one example, the transmission clutch can be determined to be open and the gear is locked in response to an actuator sensor in the transmission. The torque transmitted from the transmission input shaft to the transmission output shaft can be determined by locking the transmission output shaft. If method 600 determines that the transmission input clutch is open and the transmission output shaft is locked in a fixed position to prevent rotation, the result is yes and method 800 proceeds to 806. Otherwise, the result is no and method 800 proceeds to 850.

[0184] At 806, method 800 determines whether the engine torque is low enough to allow the ISG or BISG torque to control the engine speed in the speed control mode. In one example, method 800 may determine that the engine torque is low enough to control the engine speed via the ISG or BISG when the engine torque is less than a threshold torque. If method 800 determines that the engine torque is low enough to allow the ISG or BISG torque to control the engine speed in the speed control mode, the result is yes and method 800 proceeds to 808. Otherwise, the result is no and method 800 proceeds to 850.

[0185] At 808, method 800 operates the ISG or BISG in a speed control mode with its reference speed according to the driver's demand acceleration. In addition, the engine is commanded to a constant torque in a torque control mode. In the torque control mode, the speed of the engine is allowed to vary, while the engine torque is controlled to a reference value (e.g., a constant). Therefore, if the load on the engine is reduced and the engine outputs a constant torque value, the engine can increase from a speed of 1000RPM to a speed of 1200RPM. By commanding the ISG or BISG to reach a constant speed and the engine to reach a constant torque, the engine and ISG or BISG speeds can be kept constant. By operating the ISG or BISG at a speed when the transmission output shaft is locked at zero speed, applying or closing the transmission shift element can transfer torque from the ISG or BISG to the locked transmission output shaft, so that the torque transmitted by the transmission shift element can be determined. The transmission output shaft can be locked by placing the transmission in a parking gear or applying wheel brakes. Method 800 proceeds to 810.

[0186] At 810, method 600 closes the transmission input clutch and then applies a predetermined amount to one of the transmission's shift elements. In one example, the position of the shift fork is adjusted in response to a desired transmission shift element torque (e.g., the amount of torque that the shift element can transmit at a given shift fork position). The shift fork adjusts the position of the synchronizer, its friction elements, and teeth. The desired transmission shift element torque can be based on a transfer function or shift profile stored in a controller non-transient memory, and the transmission shift element can be adjusted to a suitable position in response to a transfer function that associates the desired transmission shift element torque with the transmission shift fork position. For example, a table or function stored in a non-transient or temporary memory can maintain a transmission shift fork position, and the table or function can output a transmission shift element position in response to a desired transmission shift element torque that references or indexes the table or function. The table or function can store multiple transmission shift fork positions that can be individually referenced by different desired transmission shift element torque values. The transmission shift fork can be adjusted to each transmission shift fork position to calibrate and / or verify that the transmission shift element is transmitting the amount of torque in the table or function corresponding to each transmission shift fork position. Method 800 commands the transmission shift fork to a position in the table or function after the transmission input clutch is fully closed, and then method 800 proceeds to 812.

[0187] It should be noted that other transmission shift elements, such as brake bands, may be adjusted in a similar manner to characterize their operation. For example, a servo system may be commanded to a position in a table or function to provide a desired amount of brake band torque. The amount of brake band torque may be estimated by the ISG or BISG torque, and thus the function or table describing the operation of the brake band torque may be adjusted or tuned.

[0188] At 812, method 800 determines the amount of torque transmitted to the transmission output shaft via the transmission shift element. In one example, method 800 determines the change in ISG or BISG torque by subtracting the ISG or BISG torque at the time immediately before the transmission shift element is applied from the ISG or BISG torque immediately after the transmission shift element is applied to a position that should provide the desired transmission shift element torque and the transmission shift element position is stable (e.g., a change of less than 5%). The ISG or BISG torque before the transmission shift element is applied and the torque after the transmission shift element is applied can be determined in response to the ISG or BISG current. For example, a current of 0.5 amperes can correspond to an ISG or BISG torque of 10 N-m. The method determines the change in ISG or BISG current by subtracting the ISG or BISG current before the transmission shift element is applied from the ISG or BISG current after the transmission shift element is applied. The change in ISG or BISG torque is the amount of torque transmitted by the transmission shift element since the transmission input clutch is fully closed. If the amount of torque transmitted by the transmission shift element as determined based on the ISG or BISG current is not equal to a value in a table or function (e.g., a transmission input clutch transfer function), the value in the table corresponding to the current position of the transmission shift element will be modified with the torque determined based on the ISG or BISG current. For example, if the transmission shift element is applied by moving the shift fork to a position three millimeters from an unapplied position that should have a transmission shift element torque value of 4 N-m, but the ISG torque or BISG torque determined based on the ISG or BISG current indicates that the torque transmitted by the transmission shift element is 3 N-m, the table or function in memory updates the three millimeter position in the table or function with a value of 3 N-m. Method 800 proceeds to 814 after the transmission input clutch is applied to the specified position.

[0189] At 814, method 800 determines whether all values ​​in a function or table (e.g., a transmission input clutch transfer function) describing the operation of a transmission shift element have been calibrated or verified. For example, if the function or table includes four pairs of values ​​describing the operation of a transmission shift element and three pairs of values ​​have been calibrated or verified, the result is no, and method 800 proceeds to 820. However, if four pairs of values ​​have been calibrated or verified, the result is yes, and method 800 proceeds to 816.

[0190] At 820, method 800 adjusts the position of the transmission shift element to a new position, which may be a position included in a table or function describing the transmission shift element torque in response to the transmission fork position. For example, if the function or table includes a transmission shift fork position of 5 mm and a position of 7 mm, and if the transmission shift fork has been moved to the 5 mm position, the transmission shift fork is moved to the 7 mm position. Method 800 returns to 812.

[0191] It should be noted that if vehicle operating conditions cause method 800 to exit without adapting, adjusting or verifying all positions in a table or function describing the operation of a transmission shift element, method 800 can later resume the adapted values ​​in the table or function starting from the values ​​in the table or function that were not previously adjusted or verified. In addition, method 800 can be executed for each shift element in the transmission.

[0192] At 816, method 800 operates the transmission input clutch according to a table or function describing the operation of the transmission shift element including any values ​​that may have been adjusted. For example, if the transmission shift element is expected to transmit 5N-m of torque, the transmission shift fork is adjusted to a position corresponding to the transmission shift element being able to transmit 5N-m of torque. Method 800 continues to exit.

[0193] In this way, the operation and control of the transmission shift elements can be adjusted, and the values ​​in the tables or functions describing the operation of the transmission shift elements can be modified as the vehicle and transmission age. Each transmission shift element can have a separate function or table describing their operation, and method 800 can be the basis for adjusting the function or table for each transmission shift element.

[0194] Reference now Fig. 9 , which shows that according to Figure 8 The method predicts the transmission shift element torque characterization sequence. Figure 8 Combination of methods Figures 1A-3B The system operates to provide Fig. 9 sequence. Fig. 9 The data in the graphs of occur simultaneously and the graphs are aligned in time. The vertical markers at times T20-T25 represent times of interest during the sequence.

[0195] from Fig. 9 The first graph starting from the top of FIG. 902 is a graph of the transmission shift element representative state versus time. When the trace 902 is at a higher level near the vertical axis arrow, the transmission shift element representative state is active. When the trace 902 is at a lower level near the vertical axis arrow, the transmission shift element representative state is not activated. The horizontal axis represents time and time increases from the left side of the graph to the right side of the graph.

[0196] from Fig. 9 The second graph from the top of is a graph of ISG or BISG torque versus time. The vertical axis represents ISG or BISG torque, and the ISG or BISG torque increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0197] from Fig. 9 The third graph from the top of FIG. 1 is a graph of transmission shift element torque (e.g., the amount of torque that the transmission shift element can transmit as currently applied) versus time. The vertical axis represents the transmission shift element torque, and the transmission shift element torque increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0198] At time T20, the transmission shift element torque representative state is not asserted, so there is no need to determine and modify the transmission shift element position. The ISG or BISG torque is at a low level. The transmission shift element torque is zero, indicating that the transmission shift element is fully open and / or not applied.

[0199] At time T21, the transmission shift element torque characterizing state changes from a low value to a high value to request a characterizing transmission shift element torque. The BISG or ISG torque value remains at the previous level. In addition, the transmission shift element torque remains at zero. The ISG or BISG is in speed control mode. The transmission output shaft is locked by applying the vehicle brake or engaging the parking pawl (not shown).

[0200] Between time T21 and time T22, the ISG or BISG torque is determined from the ISG or BISG current and stored in memory. The ISG or BISG torque remains constant and the transmission shift element torque characterizing state remains valid.

[0201] At time T22, the transmission shift element torque is increased in a step-like manner so that the transmission shift element begins to transfer torque to the transmission or wheels. The transmission shift element torque can be increased by adjusting the position of the shift fork and the transmission shift element. The ISG or BISG torque is increased to maintain the ISG or BISG speed and the engine speed. The transmission shift element torque characterization state remains valid. The BISG or ISG torque change is compared to the commanded transmission shift element torque change, and if there is a difference, the table or function describing the transmission shift element operation is corrected with the torque determined by the BISG or ISG (not shown).

[0202] At time T23, the transmission shift element torque is increased a second time in a stepwise manner. In addition, the ISG or BISG torque is increased in a stepwise manner to maintain the engine and ISG or BISG speeds. The transmission shift element torque characterizing state remains valid.

[0203] At time T24, the transmission shift element torque is reduced to zero in a step-like manner, and the BISG or ISG torque is reduced in response to the reduction of the lowered transmission shift element torque, so that the engine and ISG speeds can be maintained.

[0204] At time T25, the transmission shift element torque characterization state transitions to a low state to indicate that the transmission shift element torque characterization is not being performed. The transmission shift element torque value also remains at zero.

[0205] In this way, the transmission shift element operation can be characterized and the transfer function describing the transmission shift element operation can be adjusted or tuned. The transmission shift element transfer function can be tuned as the vehicle ages so that the vehicle consistently shifts over time.

[0206] therefore, Figure 4 , 6 The method of 8 provides a powertrain operating method, comprising: at least partially engaging a gear synchronizer or a band brake while rotating a transmission input shaft via an electric motor, keeping a transmission output shaft stopped while rotating the transmission input shaft via the electric motor; and adjusting a transmission shift in response to torque transmitted via the gear synchronizer or the band brake. The method includes the synchronizer being included in a dual clutch transmission. The method includes the band brake being included in a transmission including a planetary gear set.

[0207] In some examples, the method further includes: operating the motor in a speed control mode in which the motor follows a desired speed. The method includes torque transmitted via a gear synchronizer or a band brake according to current supplied to the motor, while at least partially engaging the gear synchronizer or the band brake while rotating the transmission input shaft via the motor. The method includes the transmission output shaft being held stationary while rotating the transmission input shaft via wheel brakes. The method includes the transmission output shaft being held stationary by a parking pawl.

[0208] Figure 4 , 6The method of and 8 also provides a powertrain operating method, comprising: rotating a first side of a transmission input clutch at a first speed via a first motor while a transmission output shaft rotates at a second speed via a second motor; at least partially engaging the transmission input clutch; and adjusting a transmission shift in response to torque transmitted via the transmission input clutch. The method also includes operating the first motor in a speed control mode while rotating the first side of the transmission input clutch via the first motor. The method also includes adjusting a transfer function describing the operation of the transmission input clutch in response to a change in torque of the first motor when the first motor is operating in the speed control mode.

[0209] In some examples, the method further includes operating the second electric machine in a speed control mode and maintaining a vehicle speed in response to an increased torque transmitted via a transmission input clutch. The method further includes operating the engine at a constant torque while rotating a first side of the transmission input clutch via the first electric machine. The method includes the first speed being greater than a ratio of the second speed multiplied by an engaged gear of the transmission. The method includes the first speed being less than a ratio of the second speed multiplied by an engaged gear of the transmission.

[0210] Note that the exemplary control and estimation routines included herein can be used with various engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in a non-transitory memory and can be executed by a control system including a controller in combination with various sensors, actuators, and other engine hardware. In addition, parts of these methods can be physical actions taken in the real world to change the state of the device. The specific routines described herein can represent one or more of any number of processing strategies (e.g., event-driven, interrupt-driven, multi-tasking, multi-threading, etc.). In this way, the various actions, operations, and / or functions shown can be performed in the order shown, in parallel, or in some cases can be omitted. Similarly, the order of processing does not necessarily need to realize the features and advantages of the example examples described herein, but is provided for ease of illustration and description. Depending on the specific strategy used, one or more of the actions, operations, and / or functions shown can be repeatedly performed. In addition, the described actions, operations, and / or functions can graphically represent the code in the non-transitory memory of a computer-readable storage medium to be programmed into the engine control system, wherein the described actions are implemented by executing instructions in the system, which includes various engine hardware components combined with an electronic controller. If desired, one or more of the method steps described herein may be omitted.

[0211] It should be understood that the configurations and routines disclosed herein are exemplary in nature, and that these specific examples are not to be considered limiting, as many variations are possible. For example, the above-described techniques may be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0212] The following claims particularly point out certain combinations and subcombinations believed to be novel and non-obvious. These claims may refer to "an" element or a "first" element or the equivalent thereof. These claims should be understood to include combinations of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or characteristics may be claimed by amendment of the present claims or by presenting new claims in this or a related application. Such claims (whether broader, narrower, equal, or different in scope than the original claims) are also considered to be included in the subject matter of the present disclosure.

Claims

1. A method for operating a power transmission system, comprising: at least partially engaging a gear synchronizer or a belt while rotating a transmission input shaft via a first motor, operating a second motor included in a rear drive unit while rotating the transmission input shaft via the first motor; and The second motor is operated in a speed control mode while the output torque of the first motor is changed while the gear synchronizer or belt is closed, and the transmission is operated in response to currents supplied to the first motor and the second motor just before the output torque of the first motor is changed and currents supplied to the first motor and the second motor just after the output torque of the first motor is changed. 2 . The method of claim 1 , wherein the synchronizer is included in a dual clutch transmission. 3 . The method of claim 1 , wherein the belt is included in a transmission including a planetary gear set. 4 . The method of claim 1 , further comprising operating the first motor in a speed control mode in which the first motor follows a desired speed. 5 . The method of claim 4 , wherein the torque transmitted via the gear synchronizer or belt is based on current supplied to the motor when the gear synchronizer or belt is at least partially engaged while rotating the transmission input shaft via the motor.

6. A system comprising: First motor; a transmission selectively mechanically connectable to the first electric machine via an input clutch; a second electric machine included in a rear drive unit mechanically connected to an output shaft of the transmission; and A controller including executable instructions stored in a non-transitory memory for operating the second motor in a speed control mode while changing the output torque of the first motor while the input clutch and gear clutch of the transmission are closed, and instructions for operating the transmission in response to current supplied to the first motor and the second motor immediately before changing the output torque of the first motor and current supplied to the first motor and the second motor immediately after changing the output torque of the first motor.

7. The system of claim 6 further comprising operating the transmission with the input clutch closed and the gear clutch closed.

8. The system of claim 6, further comprising estimating a transmission torque ratio in response to the current supplied to the first and second motors immediately before and immediately after changing the output torque of the first motor.

9. The system of claim 6, wherein the instruction to operate the transmission in response to the electrical current includes shifting a transmission gear. 10 . The system of claim 6 , wherein operating the second electric machine in the speed control mode includes maintaining a constant vehicle speed.

11. The system of claim 6 further estimating transmission efficiency based on the current supplied to the first and second motors immediately before and after the output torque of the first motor is changed.

12. A method for operating a power transmission system, comprising: rotating a first side of a transmission input clutch at a first speed via a first electric machine while rotating a transmission output shaft at a second speed via a second electric machine; at least partially engaging the transmission input clutch; and The second motor is operated in a speed control mode while the output torque of the first motor is changed while the transmission input clutch is closed, and the transmission is operated in response to currents supplied to the first motor and the second motor immediately before the output torque of the first motor is changed and currents supplied to the first motor and the second motor immediately after the output torque of the first motor is changed.

Images