Method and system for predicting driveline disconnect clutch torque

Abstract

The present disclosure provides "Methods and systems for predicting driveline disconnect clutch torque." Systems and methods for operating a hybrid drivetrain including an engine and a motor / generator are described. The systems and methods provide a way to estimate driveline disconnect clutch torque such that driveline torque disturbances can be reduced. In one example, driveline disconnect clutch torque capacity and engine torque can be the basis for estimating driveline disconnect clutch torque.

Description

TECHNICAL FIELD

[0001] The present specification relates to methods and systems for operating a powertrain system of a hybrid vehicle. The methods and systems are particularly useful for hybrid vehicles that include a driveline disconnect clutch. BACKGROUND

[0002] A hybrid vehicle can include multiple controllers to operate the driveline of the vehicle. For example, a hybrid vehicle can include a vehicle system controller, an engine controller, a transmission controller, a motor controller, and a brake controller. The vehicle system controller can request torque in response to a driver demand torque. The requested torque can be distributed between torque provided by an engine and torque provided by a motor. The vehicle system controller can communicate an engine torque request to the engine controller. Additionally, the vehicle system controller can communicate a motor request to the motor controller. The engine torque request and the motor torque request can be broadcast over a controller area network (CAN), and communication over the CAN can cause a delay in the arrival of the torque requests at the various controllers of the distribution. As a result, the torque delivered by the engine and the motor can not accurately follow the requested engine and motor torque.

[0003] Some hybrid vehicle drivelines can include a driveline disconnect clutch to mechanically couple an engine to a motor. The driveline disconnect clutch can transition from an open state to a closed state during engine start-up, or during periods when the engine is idling while the motor propels the vehicle without engine assistance. The engine can be started by closing the driveline disconnect clutch and accelerated toward the rotational speed of the motor that is propelling the hybrid vehicle. Closing the driveline disconnect clutch increases the load applied to the motor, and increasing the load on the motor can decelerate the vehicle and create a driveline torque disturbance if the motor torque is not compensated for. However, even if the motor torque is compensated for, a driveline torque disturbance can occur due to the communication of the torque requests over the CAN. Therefore, it can be desirable to provide a method of compensating for a driveline disconnect clutch torque in a vehicle system, where the torque requests can be communicated to different controllers. SUMMARY

[0004] The present inventors have recognized the above problems and have developed a vehicle system that includes a motor, an engine, a driveline disconnect clutch mechanically coupled to the engine and the motor, and one or more controllers including executable instructions stored in non-transitory memory to adjust an engine torque actuator in response to a driveline disconnect clutch torque, the driveline disconnect clutch torque based on an engine torque and a driveline disconnect clutch torque capacity.

[0005] By estimating the driveline decoupling clutch torque in response to the engine torque and the driveline decoupling clutch torque capacity, a predicted value of the driveline decoupling clutch torque can be provided. In particular, the inventors have recognized that a prediction of the driveline decoupling clutch torque can be provided in response to the driveline decoupling clutch torque capacity, the engine torque, and the driveline decoupling clutch slip. The prediction is based on the recognition that the driveline decoupling clutch torque can transition from the driveline decoupling clutch torque capacity to the engine torque. The blending of the driveline decoupling clutch torque capacity and the engine torque helps to time align the motor compensation torque with the physical step change in actual driveline clutch torque, so that CAN communication delays can be compensated for and so that the actual engine torque can be adjusted to provide a smooth driveline torque progression.

[0006] The present specification can provide several advantages. In particular, the method can provide an improved prediction of the driveline decoupling clutch torque, so that driveline torque compensation can be improved. Moreover, the method can be provided without requiring additional engine sensors or actuators. Furthermore, the method can improve engine launch when the vehicle is propelled by the motor.

[0007] The above advantages and other advantages and features of the present specification will be apparent from the following "DETAILED DESCRIPTION," which

[0008] It should be understood that the foregoing Summary is provided merely for purposes of summarizing some implementation so as to provide a basic understanding of BRIEF DESCRIPTION OF DRAWINGS

[0009] The advantages described herein will be more fully understood from the following

[0010] Figure 1 is a schematic diagram of an engine.

[0011] Figure 2 is a schematic diagram of a hybrid vehicle powertrain.

[0012] Figure 3 is a graph illustrating an exemplary driveline decoupling clutch lockup profile.

[0013] Figure 4 is a graph illustrating an exemplary driveline decoupling clutch torque estimation zone.

[0014] Figure 5 and Figure 6 An exemplary driveline disconnect clutch torque prediction sequence is shown.

[0015] Figure 7 An exemplary flowchart of a method for predicting driveline disconnect clutch torque and operating a vehicle driveline is shown. DETAILED DESCRIPTION

[0016] This specification relates to predicting driveline disconnect clutch torque to improve driveline torque compensation. To achieve greater driveline torque generation, provide engine braking, facilitate battery charging, or for other reasons, a driveline disconnect clutch can be closed during engine start-up or after the engine enters a cruise mode. The engine can be of the type described in Figure 1 or a diesel engine. The engine can be included in a hybrid vehicle driveline, as shown in Figure 2 The driveline disconnect clutch can be locked under different conditions, as shown in Figure 3 Driveline disconnect clutch torque can be predicted according to different driveline disconnect clutch operating regions or zones, as shown in Figure 4 Figure 5 and Figure 6 Two different engine start-ups including closing a driveline disconnect clutch are shown. Figure 7 A method for estimating driveline disconnect clutch torque and operating a driveline is shown in

[0017] Referring to Figure 1 , an internal combustion engine 10 including a plurality of cylinders is controlled by an electronic engine controller 12, with one cylinder shown in Figure 1 ​The engine 10 is comprised of a cylinder head 35 and a cylinder block 33, which includes combustion chambers 30 and cylinder walls 32. A piston 36 is located therein and reciprocates by connection to a crankshaft 40. A flywheel 97 and a ring gear 99 are coupled to the crankshaft 40. A starter 96 (e.g., a low voltage (operates at less than 30 volts) electric motor) includes a pinion shaft 98 and a pinion gear 95. The pinion shaft 98 can selectively advance the pinion gear 95 to engage the ring gear 99. The starter 96 can be mounted directly to the front of the engine or to the rear of the engine. In some examples, the starter 96 can selectively supply torque to the crankshaft 40 through a belt or chain. In one example, the starter 96 is in a quiescent state when not engaged to the engine crankshaft. The combustion chambers 30 are shown in communication with an intake manifold 44 and an exhaust manifold 48 by respective intake valves 52 and exhaust valves 54. Each intake and exhaust valve can be operated by an intake cam 51 and an exhaust cam 53. The position of the intake cam 51 can be determined by an intake cam sensor 55. The position of the exhaust cam 53 can be determined by an exhaust cam sensor 57. The intake valves 52 can be selectively activated and deactivated by a valve activation device 59. The exhaust valves 54 can be selectively activated and deactivated by a valve activation device 58. The valve activation devices 58 and 59 can be electromechanical devices.

[0018] A fuel injector 66 is shown positioned to inject fuel directly into the cylinder 30, which is known in the art as direct injection. The fuel injector 66 delivers liquid fuel in proportion to the pulse width from the controller 12. The fuel is delivered to the fuel injector 66 by a fuel system (not shown) including a fuel tank, a fuel pump, and a fuel rail (not shown). In one example, a high pressure two-stage fuel system can be used to generate higher fuel pressures.

[0019] Further, the intake manifold 44 is shown in communication with a turbocharger compressor 162 and an engine air intake 42. In other examples, the compressor 162 can be a supercharger compressor. A shaft 161 mechanically couples a turbocharger turbine 164 to the turbocharger compressor 162. An optional electronic throttle 62 adjusts the position of a throttle plate 64 to control the flow of air from the compressor 162 to the intake manifold 44. The pressure in the plenum 45 can be referred to as the throttle inlet pressure because the inlet of the throttle 62 is within the plenum 45. The throttle outlet is in the intake manifold 44. In some examples, the throttle 62 and the throttle plate 64 can be located between the intake valves 52 and the intake manifold 44 such that the throttle 62 is a ported throttle. A compressor recirculation valve 47 can be selectively adjusted between full open and full closed. The wastegate 163 can be adjusted via the controller 12 to allow exhaust gases to selectively bypass the turbine 164 to control the speed of the compressor 162. An air cleaner 43 cleans the air entering the engine air intake 42.

[0020] The distributorless ignition system 88 provides an ignition spark to the combustion chamber 30 through a spark plug 92 in response to the controller 12. A universal exhaust gas oxygen (UEGO) sensor 126 is shown coupled to the exhaust manifold 48 upstream of the catalytic converter 70. Alternatively, a two-state exhaust gas oxygen sensor can be used in place of the UEGO sensor 126.

[0021] In one example, the converter 70 can include a plurality of catalyst bricks. In another example, a plurality of emission control devices can be used, each having a plurality of bricks. In one example, the converter 70 can be a three-way catalyst.

[0022] The controller 12 is shown in Figure 1 a conventional microcomputer, including a microprocessor unit 102, input / output ports 104, read only memory 106 (e.g., non-transitory memory), random access memory 108, a keep-alive memory 110, and a conventional data bus. In addition to those signals previously discussed, the controller 12 is shown receiving various signals from sensors coupled to the engine 10, including engine coolant temperature (ECT) from a temperature sensor 112 coupled to the cooling jacket 114, a position sensor 134 coupled to the accelerator pedal 130 for sensing force applied by a human foot 132, a position sensor 154 coupled to the brake pedal 150 for sensing force applied by a foot 152, engine manifold pressure (MAP) measurements from a pressure sensor 122 coupled to the intake manifold 44, engine position from a Hall effect sensor 118 sensing the position of the crankshaft 40, measurements of mass of air entering the engine from a sensor 120, and throttle position measurements from a sensor 68. Atmospheric pressure can also be sensed (sensor not shown) for processing by the controller 12. In one preferred aspect of the present description, the engine position sensor 118 produces a predetermined number of equally spaced pulses per revolution of the crankshaft, from which engine rotational speed (RPM) can be determined. The engine rotational speed at the sensor 118 is equal to Figure 2 The rotational speed of the first side 235 of the driveline disconnect clutch 236 is shown in

[0023] During operation, each cylinder within engine 10 typically experiences a four-stroke cycle comprising an intake stroke, a compression stroke, a power stroke, and an exhaust stroke. During the intake stroke, typically, exhaust valve 54 is closed and intake valve 52 is open. Air is introduced into combustion chamber 30 through intake manifold 44, and piston 36 moves to the bottom of the cylinder to increase the volume within combustion chamber 30. The position of piston 36 near the bottom of the cylinder and at the end of its stroke, for example when combustion chamber 30 is at its maximum volume, is commonly referred to as bottom dead center (BDC) by those skilled in the art.

[0024] During the compression stroke, intake valve 52 and exhaust valve 54 are closed. Piston 36 moves toward the cylinder head in order to compress the air within combustion chamber 30. The point at which piston 36 ends its stroke and is closest to the cylinder head, for example when combustion chamber 30 is at its minimum volume, is commonly referred to as top dead center (TDC) by those skilled in the art. In a process referred to hereafter as injection, fuel is introduced into the combustion chamber. In a process referred to hereafter as ignition, the injected fuel is ignited by a known ignition device, such as spark plug 92, causing combustion.

[0025] During the expansion stroke, the expanding gases push piston 36 back to BDC. Crankshaft 40 converts the piston motion into rotational torque of the rotational shaft. Finally, during the exhaust stroke, exhaust valve 54 opens to release the combusted air-fuel mixture to exhaust manifold 48, and the piston returns to TDC. It should be noted that the above is shown by way of example only, and the intake and exhaust valve opening and / or closing timing can be varied, for example to provide positive or negative valve overlap, intake valve late closing, or various other examples.

[0026] Figure 2 is a block diagram of a vehicle 225 including a powertrain system or driveline 200. Figure 2 The powertrain system of includes Figure 1The powertrain system 200 is shown to include a vehicle system controller 255, an engine controller 12, an electric machine controller 252, a transmission controller 254, an energy storage device controller 253, and a brake controller 250. The controllers can communicate over a controller area network (CAN) 299. Each of the controllers can provide information to the other controllers, such as: torque output limits (e.g., torque outputs of devices or components that are controlled not to be exceeded), torque input limits (e.g., torque inputs of devices or components that are controlled not to be exceeded), sensor and actuator data, diagnostic information (e.g., information about a deteriorating transmission, information about a deteriorating engine, information about a deteriorating electric machine, information about a deteriorating brake). In addition, the vehicle system controller can provide commands to the engine controller 12, the electric machine controller 252, the transmission controller 254, and the brake controller 250 to implement driver input requests and other requests based on vehicle operating conditions. Status information can be provided to the driver through a human / machine interface 256 (e.g., a keyboard and display).

[0027] For example, in response to the driver releasing the accelerator pedal and the vehicle speed, the vehicle system controller 255 can request a desired wheel torque or wheel power level to provide a desired vehicle deceleration rate. The desired wheel torque can be provided by the vehicle system controller 255 that requests a first braking torque from the electric machine controller 252 and a second braking torque from the brake controller 250 that provide a desired braking torque at the wheels 216.

[0028] In other examples, the powertrain control devices can be partitioned in a manner different than shown in FIG. 2. For example, a single controller can replace the vehicle system controller 255, the engine controller 12, the electric machine controller 252, the transmission controller 254, and the brake controller 250. Figure 2

[0029] In this example, the powertrain system 200 can be powered by the engine 10 and the electric machine 240. The engine 10 can be started with the engine starting system shown in FIG. 1 or via an integrated starter / generator (ISG) 240. The ISG 240 (e.g., a high voltage (operating at greater than 30 volts) electric machine) can also be referred to as an electric machine, a motor, and / or a generator. In addition, the torque of the engine 10 can be adjusted via torque actuators 204, such as fuel injectors, throttle valves, etc. Figure 1

[0030] ​​Engine output torque can be transmitted to the input side or first side of the powertrain disconnect clutch 235 via the dual mass flywheel 215. The disconnect clutch 236 can be electrically or hydraulically actuated. The downstream side or second side 234 of the disconnect clutch 236 is shown mechanically coupled to the ISG input shaft 237.

[0031] The ISG 240 can be operated to provide torque to the powertrain 200 or in a regenerative mode to convert powertrain torque into electrical energy that will be stored in the electrical energy storage device 275. The ISG 240 has a higher output torque capacity than the starter 96 shown in FIG. 1. In addition, the ISG 240 directly drives the powertrain 200 or is directly driven by the powertrain 200. There are no belts, gears, or chains coupling the ISG 240 to the powertrain 200. Rather, the ISG 240 rotates at the same rate as the powertrain 200. The electrical energy storage device 275 (e.g., high voltage battery or power supply) can be a battery, a capacitor, or an inductor. The downstream side of the ISG 240 is mechanically coupled by a shaft 241 to the pump 285 of the torque converter 206. A rotational speed sensor 273 senses the torque converter pump rotational speed, which is equal to the rotational speed of the second side 234 of the powertrain disconnect clutch 236. The upstream side of the ISG 240 is mechanically coupled to the disconnect clutch 236. The ISG 240 can provide positive or negative torque to the powertrain 200 by operating as a motor or generator as commanded by the motor controller 252. Figure 1

[0032] The torque converter 206 includes a turbine 286 to output torque to an input shaft 270. The input shaft 270 mechanically couples the torque converter 206 to the automatic transmission 208. The torque converter 206 also includes a torque converter bypass lock-up clutch 212 (TCC). When the TCC is locked, torque is passed directly from the pump 285 to the turbine 286. The TCC is electrically operated by the controller 12. Alternatively, the TCC can be hydraulically locked. In one example, the torque converter can be referred to as a component of the transmission.

[0033] ​When the torque converter lock-up clutch 212 is fully disengaged, the torque converter 206 transmits engine torque to the automatic transmission 208 through fluid transfer between the torque converter turbine 286 and the torque converter pump wheel 285, thereby enabling torque multiplication. Conversely, when the torque converter lock-up clutch 212 is fully engaged, engine output torque is transmitted directly to the input shaft (not shown) of the transmission 208 via the torque converter clutch. Alternatively, the torque converter lock-up clutch 212 can be partially engaged, thereby enabling the amount of torque transmitted directly to the transmission to be adjusted. The controller 12 can be configured to adjust the amount of torque transmitted by the torque converter 212 by adjusting the torque converter lock-up clutch in response to various engine operating conditions or based on engine operating requests by the driver.

[0034] The automatic transmission 208 includes gear clutches (e.g., gears 1-10) 211 and a forward clutch 210. The automatic transmission 208 is a fixed-ratio transmission. The gear clutches 211 and the forward clutch 210 can be selectively engaged to change the ratio of the actual total revolutions of the input shaft 270 to the actual total revolutions of the wheels 216. The gear clutches 211 can be engaged or disengaged by adjusting the fluid supplied to the clutches via the shift control solenoids 209. Torque output from the automatic transmission 208 can also be transmitted to the wheels 216 via the output shaft 260 to propel the vehicle. In particular, the automatic transmission 208 can transfer an input drive torque at the input shaft 270 and then transmit an output drive torque to the wheels 216 in response to vehicle travel conditions. The transmission controller 254 selectively activates or engages the TCC 212, the gear clutches 211, and the forward clutch 210. The transmission controller also selectively deactivates or disengages the TCC 212, the gear clutches 211, and the forward clutch 210.

[0035] Furthermore, a frictional force can be applied to the wheels 216 by engaging the frictional wheel brakes 218. In one example, the frictional wheel brakes 218 can be engaged in response to the driver pressing his foot on the brake pedal (not shown) and / or in response to instructions within the brake controller 250. Additionally, the brake controller 250 can apply the brakes 218 in response to information and / or requests given by the vehicle system controller 255. In the same manner, the frictional force on the wheels 216 can be reduced by disengaging the 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, as part of an automatic engine stop procedure, the vehicle brakes can apply a frictional force to the wheels 216 by the controller 250.

[0036] In response to a request to accelerate the vehicle 225, the vehicle system controller can obtain a driver demand torque or power request from the accelerator pedal or other device. The vehicle system controller 255 then allocates a portion of the requested driver demand torque to the engine and the remainder to the ISG. The vehicle system controller 255 requests an engine torque from the engine controller 12 and an ISG torque from the motor controller 252. If the ISG torque plus the engine torque is less than a transmission input torque limit (e.g., a threshold that should not be exceeded), the torque is delivered to the torque converter 206, which then transmits at least a portion of the requested torque to the transmission input shaft 270. The transmission controller 254 selectively locks the torque converter clutch 212 and engages a gear through the gear clutch 211 in response to shift schedules and TCC lock schedules that can be based on input shaft torque and vehicle speed. In some cases, a charging torque (e.g., a negative ISG torque) can be requested while there is a non-zero driver demand torque when it can be desirable to charge the electrical energy storage device 275. The vehicle system controller 255 can request an increased engine torque to overcome the charging torque to satisfy the driver demand torque.

[0037] In response to a request to decelerate the vehicle 225 and provide regenerative braking, the vehicle system controller can provide a negative desired wheel torque based on vehicle speed and brake pedal position. The vehicle system controller 255 then allocates a portion of the negative desired wheel torque to the ISG 240 (e.g., a desired driveline wheel torque) and the remainder to the friction brakes 218 (e.g., a desired friction brake wheel torque). Additionally, the vehicle system controller can inform the transmission controller 254 that the vehicle is in regenerative braking mode so that the transmission controller 254 shifts gears 211 based on unique shift schedules to improve regenerative efficiency. While the ISG 240 supplies a negative torque to the transmission input shaft 270, the negative torque provided by the ISG 240 can be limited by the transmission controller 254, which outputs a transmission input shaft negative torque limit (e.g., a threshold that should not be exceeded). Additionally, based on operating conditions of the electrical energy storage device 275, the vehicle system controller 255 or the motor controller 252 can limit the negative torque of the ISG 240 (e.g., constrained to less than a negative threshold torque). Any portion of the desired negative wheel torque that can not be provided by the ISG 240 due to driveline or ISG limitations can be allocated to the friction brakes 218 so that the desired wheel torque is provided by the combination of negative wheel torque from the friction brakes 218 and the ISG 240.

[0038] Accordingly, torque control of various powertrain components can be monitored by the vehicle system controller 255, with local torque control of the engine 10, transmission 208, electric machine 240, and brakes 218 provided via the engine controller 12, electric machine controller 252, transmission controller 254, and brake controller 250.

[0039] As one example, engine torque output can be controlled by adjusting a combination of spark timing, fuel pulse width, fuel pulse timing, and / or intake air by controlling throttle opening and / or valve timing, valve lift, and supercharging of a supercharged or turbocharged engine. In the case of a diesel engine, engine torque output can be controlled by the controller 12 by controlling a combination of fuel pulse width, fuel pulse timing, and intake air. In all cases, engine control can be performed cylinder-by-cylinder to control engine torque output.

[0040] The electric machine controller 252 can control torque output and electrical energy production from the ISG 240 by adjusting current flow into and out of the field and / or armature windings of the ISG, as is known in the art.

[0041] The transmission controller 254 receives transmission input shaft position or torque converter turbine speed through a position sensor 271. The transmission controller 254 can convert transmission input shaft position to input shaft speed by differentiating the signal from the position sensor 271 or by counting a number of known angular distance pulses over a predetermined time interval. The transmission controller 254 can receive transmission output shaft torque from a torque sensor 272. Alternatively, the sensor 272 can be a position sensor or a torque and position sensor. If the sensor 272 is a position sensor, the controller 254 can count shaft position pulses over a predetermined time interval to determine transmission output shaft speed. The transmission controller 254 can also differentiate transmission output shaft speed to determine transmission output shaft acceleration.

[0042] The brake controller 250 receives wheel speed information through wheel speed sensors 221 and brake requests from the vehicle system controller 255. The brake controller 250 can also receive information from the vehicle system controller 255 directly or through the CAN 299, including vehicle speed, engine speed, and transmission input shaft speed. The brake controller 250 can also receive information from the engine controller 12, the transmission controller 254, and the electric machine controller 252, including engine torque, transmission output shaft torque, and electric machine torque. Figure 1The illustrated brake pedal sensor 154 receives brake pedal position information. The brake controller 250 can provide braking in response to wheel torque commands from the vehicle system controller 255. The brake controller 250 can also provide antiskid and vehicle stability braking to improve vehicle braking and stability. To this end, the brake controller 250 can provide wheel torque limits (e.g., threshold negative wheel torque that should not be exceeded) to the vehicle system controller 255 so that negative ISG torque does not result in exceeding the wheel torque limits. For example, if the controller 250 gives a negative wheel torque limit of 50 Nm, the ISG torque is adjusted to provide less than 50 Nm (e.g., 49 Nm) negative torque at the wheels, including accounting for transmission gear connections.

[0043] Thus, Figure 1 And Figure 2 The system of

[0044] Referring now to Figure 3 , a graph is shown that illustrates an example predicted driveline disconnect clutch lockup characteristic curve. The driveline disconnect clutch excess torque capacity versus driveline disconnect clutch slip map 300 includes a horizontal axis, a vertical axis, and four quadrants labeled 1-4. The horizontal axis represents driveline disconnect clutch (e.g., K0 clutch) slip (e.g., a difference in rotational speed between a first side of the driveline disconnect clutch and a second side of the driveline disconnect clutch). Positive driveline disconnect clutch slip applies to the first and fourth quadrants, where the rotational speed of the side of the driveline disconnect clutch coupled to the engine (e.g., the first side of the disconnect clutch) is greater than the rotational speed of the side of the driveline disconnect clutch coupled to the electric machine and the torque converter pump wheel (e.g., the second side of the disconnect clutch). Negative driveline disconnect clutch slip applies to the second and third quadrants, where the rotational speed of the side of the driveline disconnect clutch coupled to the engine is less than the rotational speed of the side of the driveline disconnect clutch coupled to the electric machine and the torque converter pump wheel.

[0045] The vertical axis represents excess driveline disconnect clutch torque capacity (e.g., excess driveline disconnect clutch torque capacity can equal driveline disconnect clutch torque capacity minus engine torque). Positive excess driveline disconnect clutch torque capacity applies to the first and second quadrants, where the driveline disconnect clutch torque capacity exceeds the engine torque. Negative excess driveline disconnect clutch torque capacity applies to the third and fourth quadrants, where the driveline disconnect clutch torque capacity is less than the engine torque.

[0046] A first driveline disconnect clutch lockup characteristic curve or locus is indicated by curve 302. In this example, curve 302 represents a driveline disconnect clutch lockup characteristic curve during a ramped engine launch, where the driveline disconnect clutch locks up once the engine speed reaches the torque converter pump wheel speed. Initially, curve 302 starts in the third quadrant at 301, where the driveline disconnect clutch slip is negative and the excess driveline disconnect clutch torque capacity is negative. For example, the clutch capacity can be zero, and the engine torque can be positive. Curve 302 crosses the horizontal axis at 350, and then the driveline disconnect clutch locks up at 352 when the slip is zero (e.g., at the vertical axis position along the horizontal axis) and when the driveline disconnect clutch torque capacity is greater than the engine torque.

[0047] A second driveline disconnect clutch lockup characteristic curve or locus is indicated by curve 304. In this example, curve 304 represents a driveline disconnect clutch lockup characteristic curve during a highly aggressive ramped engine launch, where a high engine torque is maintained throughout the engine launch. Curve 304 starts in the third quadrant at 301, where the driveline disconnect clutch slip is negative and the excess driveline disconnect clutch torque capacity is negative. Curve 304 crosses the vertical axis at 360, and then crosses the horizontal axis at 361. At 360, the engine speed is equal to the torque converter pump wheel speed, and the engine torque exceeds the driveline disconnect clutch torque capacity, so the driveline disconnect clutch does not lock up. At 361, the engine torque is equal to the driveline disconnect clutch torque capacity, and the engine speed is greater than the torque converter pump wheel speed, so the driveline disconnect clutch does not lock up. The driveline disconnect clutch locks up at 362, where the driveline disconnect clutch torque capacity exceeds the engine torque and the driveline disconnect clutch slip is zero.

[0048] A third drive-line disconnect clutch lock-up characteristic curve or locus is indicated by curve 306. In this example, curve 306 represents a drive-line disconnect clutch lock-up characteristic curve during a highly urgent ramped engine launch that occurs when a downshift of a transmission gear occurs. Curve 306 begins in the third quadrant 301 with the drive-line disconnect clutch slip being negative and the drive-line disconnect clutch torque capacity being negative. Curve 306 first crosses the vertical axis at 370 with the engine speed equal to the torque converter pump wheel speed and with the drive-line disconnect clutch torque capacity less than the engine torque. Thus, the drive-line disconnect clutch does not lock up. The drive-line disconnect clutch torque capacity continues to increase, but the engine speed increases due to the downshift. The drive-line disconnect clutch slip reaches zero a second time at 372, but the drive-line disconnect clutch does not lock up because the drive-line disconnect clutch torque capacity is less than the engine torque. At 374, the drive-line disconnect clutch torque capacity is equal to the engine torque, but the engine speed is less than the torque converter pump wheel speed, so the drive-line disconnect clutch remains unlocked. At 376, the engine speed is equal to the torque converter pump wheel speed, and the drive-line disconnect clutch torque capacity exceeds the engine torque, so the drive-line disconnect clutch locks up.

[0049] Thus, the drive-line disconnect clutch can move along different excess torque capacity and slip loci depending on the engine launch strategy and initial conditions. However, in order for the drive-line disconnect clutch to lock up, it must lock up at some location above the horizontal axis of the drive-line disconnect clutch excess torque capacity versus drive-line disconnect clutch slip map. In other words, the drive-line disconnect clutch torque capacity must be greater than the current engine torque, and the engine speed must be within a threshold speed of the torque converter pump wheel speed, for the drive-line disconnect clutch to lock up. The estimation or prediction of the drive-line disconnect clutch torque can be determined in different ways in response to the drive-line disconnect clutch excess torque capacity and the drive-line disconnect clutch slip, as discussed in the description of Figure 4 , such that improved predictions of the drive-line disconnect clutch torque can be provided.

[0050] Referring now to Figure 4 , an example graph is shown that illustrates example drive-line disconnect clutch torque prediction zones within a drive-line disconnect clutch excess torque capacity versus drive-line disconnect clutch slip map 400. The quadrants and axes of the drive-line disconnect clutch excess torque capacity versus drive-line disconnect clutch slip map 400 are the same as shown in Figure 3 . Thus, the description is not repeated here for the sake of brevity.

[0051] The transmission system disconnect clutch slip map 400 includes nine regions or zones, but a greater or lesser number of zones can be provided. The first zone is the unshaded region of quadrant one. The second zone is the unshaded region of quadrant two. The third zone is the unshaded region of quadrant three. The fourth zone is the unshaded region of quadrant four. The fifth zone is identified as shaded region 410. The sixth zone is identified as shaded region 406. The seventh zone is identified as shaded region 408. The eighth zone is identified as shaded region 402. The ninth zone is identified as shaded region 404. Each zone can be described with respect to values along the horizontal and vertical axes. These zones are used to describe how weighting factors applied to engine torque and transmission system disconnect torque capacity can be adjusted to determine transmission system disconnect clutch torque. In one example, the weighting factor applied to engine torque is designated as a1 and the weighting factor applied to transmission system disconnect clutch torque capacity is designated as b1. The value of a1 can vary in a range of 0 to 1 or between 0 and 1, and the value of b1 can vary in a range of -1 to 1 or between -1 and 1. In one example, the sum of the absolute values of a1 and b1 can be further limited between 0 and 1.

[0052] In Zone One and Zone Four, the value of a1 is 0 and the value of β1 can range from 0 to positive 1. In Zone Two and Zone Three, the value of a1 is 0 and the value of β1 can range from 0 to negative 1. In Zone Nine, the clutch torque prediction or estimation blends from the positive clutch torque capacity on the right side of Zone Nine to the engine torque on the left side of Zone Nine. For example, if the clutch operation moves from 450 to 452, then the value of a1 being 0 and the value of β1 being 1 at 450 can be adjusted to the value of a1 being 1 and the value of β1 being 0 at 452. In Zone Eight, the clutch torque prediction or estimation blends from the negative clutch torque capacity on the left side of Zone Eight to the engine torque on the right side of Zone Eight. For example, if the clutch operation moves from 455 to 457, then the value of a1 being 0 and the value of β1 being -1 at 455 can be adjusted to the value of a1 being 1 and the value of β1 being 0 at 457. In Zone Five, the clutch torque prediction or estimation blends from the negative clutch torque capacity on the left side of Zone Five to the positive clutch torque capacity on the right side of Zone Five. For example, if the clutch operation moves from 460 to 462, then the value of a1 being 0 and the value of β1 being -1 at 460 can be adjusted to the value of a1 being 0 and the value of β1 being 1 at 462. In Zone Six, the clutch torque prediction or estimation blends from the negative clutch torque capacity on the left side of Zone Six to the engine torque on the right side of Zone Six. For example, if the clutch operation moves from 465 to 467, then the value of a1 being 0 and the value of β1 being -0.8 at 465 can be adjusted to the value of a1 being 0 and the value of β1 being -1 at 467. If the clutch operation moves from 470 to 472, then the value of a1 being 0.98 and the value of β1 being -0.02 at 470 can be adjusted to the value of a1 being 0.6 and the value of β1 being -0.4 at 472. In Zone Seven, the clutch torque prediction or estimation blends from the positive driveline disconnect clutch capacity on the bottom side of Zone Seven to the engine torque on the top side of Zone Seven. For example, if the clutch operation moves from 475 to 476, then the value of a1 being 0 and the value of β1 being 1 at 475 can be adjusted to the value of a1 being 1 and the value of β1 being 0 at 476.

[0053] In this way, the weighting factors a1 and β1 can be adjusted in response to the zone in which the driveline disconnect clutch is operating. As discussed in the description of method 700, the weighting factors can be multiplied by the driveline disconnect clutch capacity and the engine torque.

[0054] Referring now to FIG. 6, Figure 5 a graph illustrating an example driveline disconnect clutch torque prediction sequence is shown. Figure 5 The sequence of FIG. 6 can be provided by a system of Figure 1 and Figure 2 in cooperation with the method of Figure 7 . Figure 5The first plot of FIG. 5 is a plot of the rotational speed of selected driveline components versus time. The vertical axis represents rotational speed and rotational speed increases along the direction of the vertical axis arrow. The horizontal axis represents time and time increases from the left side of the plot to the right side of the plot. Curve 502 represents the variator pump wheel rotational speed. Curve 506 represents the variator turbine rotational speed. Curve 504 represents the engine rotational speed.

[0055] Figure 5 The first plot of FIG. 5 is a plot of the rotational speed of selected driveline components versus time. The vertical axis represents rotational speed and rotational speed increases along the direction of the vertical axis arrow. The horizontal axis represents time and time increases from the left side of the plot to the right side of the plot. Curve 502 represents the variator pump wheel rotational speed. Curve 506 represents the variator turbine rotational speed. Curve 504 represents the engine rotational speed.

[0056] Figure 5 The second plot of FIG. 5 is a plot of the driver demand torque versus time. The vertical axis represents driver demand torque and driver demand torque increases along the direction of the vertical axis arrow. Trace 508 represents the driver demand torque. The driver demand torque can be determined by the accelerator pedal and vehicle speed. Alternatively, the driver demand torque can be provided by an autonomous vehicle controller. The horizontal axis represents time and time increases from the left side of the plot to the right side of the plot.

[0057] Figure 5 The third plot of FIG. 5 is a plot of the desired variator pump wheel torque versus time. The vertical axis represents the desired variator pump wheel torque and the desired variator pump wheel torque increases along the direction of the vertical axis arrow. Trace 510 represents the desired variator pump wheel torque. The horizontal axis represents time and time increases from the left side of the plot to the right side of the plot.

[0058] Figure 5 The fourth plot of FIG. 5 is a plot of the engine torque versus time. The vertical axis represents engine torque and engine torque increases along the direction of the vertical axis arrow. Trace 512 represents the engine torque. The horizontal axis represents time and time increases from the left side of the plot to the right side of the plot.

[0059] Figure 5 The fifth plot of FIG. 5 is a plot of the motor torque versus time. The vertical axis represents motor torque and motor torque increases along the direction of the vertical axis arrow. Trace 514 represents the motor torque. The horizontal axis represents time and time increases from the left side of the plot to the right side of the plot.

[0060] Figure 5 The sixth plot of FIG. 5 is a plot of the driveline disconnect clutch (K0) torque capacity versus time. The vertical axis represents driveline disconnect clutch torque capacity and driveline disconnect clutch torque capacity increases along the direction of the vertical axis arrow. Trace 516 represents the driveline disconnect clutch torque capacity. The horizontal axis represents time and time increases from the left side of the plot to the right side of the plot.

[0061] Figure 5The seventh curve is a graph showing the predicted drivetrain disengagement clutch torque versus time. The vertical axis represents the predicted drivetrain disengagement clutch torque, and the predicted drivetrain disengagement clutch torque increases in the direction of the arrow on the vertical axis. Trace 518 represents the predicted drivetrain disengagement clutch torque. The horizontal axis represents time, and time increases from the left side of the graph to the right side.

[0062] Figure 5 The eighth curve is a graph showing the actual transmission system disengagement clutch torque (K0) versus time. The vertical axis represents the actual transmission system disengagement clutch torque, and the actual transmission system disengagement clutch torque increases along the direction of the arrow on the vertical axis. Trace 520 represents the actual transmission system disengagement clutch torque. The horizontal axis represents time, and time increases from the left side of the graph to the right side.

[0063] Figure 5 It shows something similar to Figure 3 The illustrated drivetrain disengagement clutch trajectory 302 is an exemplary engine ramp start sequence describing the engine start sequence. At time t0, the engine speed is zero, and the torque converter pump wheel speed and torque converter turbine speed are equal and at an intermediate level. The driver's torque demand is low, and the expected torque converter pump wheel torque is low. The engine torque is zero, and the electric motor torque provides the driver's torque demand. The drivetrain disengagement clutch torque capacity is zero, and the predicted drivetrain disengagement clutch torque is zero. The actual drivetrain disengagement clutch torque is also zero. A situation may arise when the electric motor propels the vehicle. Between time t0 and time t1, exactly before time t1, the driver's torque demand increases, and the expected torque converter pump wheel torque increases to match the driver's torque demand. All other conditions remain close to their previous state.

[0064] At time t1, an engine start request is issued and the torque converter clutch (not shown) begins to disengage, allowing the torque converter pump impeller speed to deviate from the torque converter turbine speed. In response to the increased torque demand from the driver, the motor torque increases. The drivetrain disengagement clutch torque capacity is zero, the predicted drivetrain disengagement clutch torque is zero, and the actual drivetrain disengagement clutch torque is also zero.

[0065] Between time t1 and time t2, the engine speed begins to increase in response to the engine start request. The driver-demanded torque and the expected torque converter pump wheel torque continue to increase. The engine torque is zero, and the electric motor torque continues to increase in response to the increasing driver-demanded torque. The drivetrain disengagement clutch torque capacity is zero, the predicted drivetrain disengagement clutch torque is zero, and the actual drivetrain disengagement clutch torque is also zero.

[0066] At time t2, the torque converter clutch is fully unlocked (not shown), and the engine begins to produce torque through combustion of air and fuel. The engine speed begins to increase and the driver demand and desired torque converter pump torque continue to increase. The motor torque continues to increase and the driveline disconnect clutch torque capacity is zero. The predicted driveline disconnect clutch torque and the actual driveline disconnect clutch torque remain at zero.

[0067] Between time t2 and time t3, the driveline disconnect clutch begins to close such that the driveline disconnect clutch torque capacity increases. Since the motor speed is greater than the engine speed and the motor is accelerating the engine, the predicted driveline disconnect clutch torque and the actual driveline disconnect clutch torque are negative. The motor torque increases to accelerate the engine and maintain vehicle speed. The engine torque changes little and the driver demand torque stabilizes at a constant level. The desired torque converter pump torque also levels off at a constant torque, but less than the driver demand torque. The torque converter pump speed increases to a speed greater than the torque converter turbine speed.

[0068] At time t3, a request to lock the driveline disconnect clutch is issued. Shortly thereafter, the driveline disconnect clutch torque capacity begins to increase further and the magnitude of the predicted driveline disconnect clutch torque and the actual driveline disconnect clutch torque continue to increase. The motor torque increases further to compensate for engine acceleration by closing the driveline disconnect clutch. The engine speed accelerates toward the torque converter pump speed and the driver demand torque remains constant.

[0069] Between time t3 and time t4, the driveline disconnect clutch torque capacity exceeds the engine torque and the predicted driveline disconnect clutch torque begins to transition smoothly to the engine torque. The actual driveline disconnect clutch torque continues in the negative direction and the motor torque begins to decrease. The driver demand torque remains constant and the desired torque converter pump torque remains at its previous value.

[0070] At time t4, the driveline disconnect clutch locks. Shortly thereafter, the engine torque increases and as the engine torque increases, the predicted driveline disconnect clutch torque increases. In addition, as the engine torque increases, the actual driveline disconnect clutch torque increases. In response to the driveline disconnect clutch being locked, the desired torque converter pump torque also increases. The driver demand torque remains constant and the engine speed matches the torque converter pump speed. The driveline disconnect clutch torque capacity reaches a maximum value between time t4 and time t5.

[0071] At time t5, the desired torque converter pump torque and the engine torque match the driver demand torque. The predicted driveline disconnect clutch torque and the actual driveline disconnect clutch torque match the driver demand torque at time t5.

[0072] In this way, the predicted driveline disconnect clutch torque can be estimated to guide (e.g., to reach the same value before the actual driveline disconnect clutch torque reaches the same value) the actual driveline disconnect clutch torque, so that the motor torque and the engine torque can be adjusted to reduce driveline torque disturbances.

[0073] Reference is now made to Figure 6 , Figure 6 The same graphs and traces shown in Figure 5 are shown. Thus, for the sake of brevity, the description of the graphs and traces is omitted here, and only the traces of the labels are described for the sake of clarity.

[0074] In this example, trace 602 represents the torque converter pump speed. Trace 606 represents the torque converter turbine speed. Trace 604 represents the engine speed. Trace 608 represents the driver demand torque. Trace 610 represents the desired torque converter pump torque. Trace 612 represents the engine torque. Trace 614 represents the motor torque. Trace 616 represents the driveline disconnect clutch torque capacity. Trace 618 represents the predicted driveline disconnect clutch torque. Trace 620 represents the actual driveline disconnect clutch torque.

[0075] Figure 6 An example engine ramp start sequence is shown, similar to the engine start sequence described in connection with the driveline disconnect clutch trace 304 shown in Figure 3 . At time tlO, the engine speed is zero and the torque converter pump speed and the torque converter turbine speed are equal and at an intermediate level. The driver demand torque is low and the desired torque converter pump torque is low. The engine torque is zero, and the motor torque provides the driver demand torque. The driveline disconnect clutch torque capacity is zero, and the predicted driveline disconnect clutch torque is zero. The actual driveline disconnect clutch torque is also zero. Such a condition can exist while the motor is propelling the vehicle. Between time tlO and time tl 1, just before time tl 1, the driver demand torque increases and the desired torque converter pump torque increases to match the driver demand torque. All other conditions remain close to their previous states.

[0076] At time tl 1, an engine start request is made and the release of the torque converter clutch (not shown) is initiated, which allows the torque converter pump speed to diverge from the torque converter turbine speed. In response to the increase in the driver demand torque, the motor torque increases. The driveline disconnect clutch torque capacity is zero, the predicted driveline disconnect clutch torque is zero, and the actual driveline disconnect clutch torque is also zero.

[0077] Between time tl 1 and time tl 2, engine speed begins to increase in response to an engine start request. Driver demand torque and desired torque converter pump torque continue to increase. Engine torque is zero, and motor torque continues to increase in response to the increasing driver demand torque. Transmission disconnect clutch torque capacity is zero, predicted transmission disconnect clutch torque is zero, and actual transmission disconnect clutch torque is also zero.

[0078] At time tl 2, the torque converter clutch is fully unlocked (not shown), and the engine begins to produce torque by combusting air and fuel. Engine speed begins to increase and driver demand and desired torque converter pump torque continue to increase. Motor torque continues to increase and transmission disconnect clutch torque capacity is zero. Predicted transmission disconnect clutch torque and actual transmission disconnect clutch torque remain zero.

[0079] Between time tl 2 and time tl 3, the transmission disconnect clutch begins to close, such that transmission disconnect clutch torque capacity increases. Because the motor speed is greater than the engine speed and the motor is accelerating the engine, the predicted transmission disconnect clutch torque and the actual transmission disconnect clutch torque are negative. Motor torque increases to accelerate the engine and maintain vehicle speed. Engine torque decreases slightly, and driver demand torque stabilizes at a constant level. Desired torque converter pump torque also levels off at a constant torque, but less than the driver demand torque. Torque converter pump speed increases to be greater than torque converter turbine speed.

[0080] At time tl 3, a request to lock the transmission disconnect clutch is issued. Shortly thereafter, transmission disconnect clutch torque capacity begins to increase further, and the magnitude of the predicted transmission disconnect clutch torque and the actual transmission disconnect clutch torque continue to increase. Shortly thereafter, motor torque increases further to compensate for engine acceleration by closing the transmission disconnect clutch. Engine speed accelerates toward torque converter pump speed, and driver demand torque remains constant.

[0081] Between time tl 3 and time tl 4, engine speed approaches torque converter pump speed. Because transmission disconnect clutch torque capacity is much lower than engine torque, the predicted transmission disconnect clutch torque mixes from negative transmission disconnect clutch torque capacity to positive transmission disconnect clutch torque capacity. As transmission disconnect clutch torque capacity continues to increase, transmission disconnect clutch slip decreases, such that transmission disconnect clutch torque is estimated by mixing transmission disconnect clutch torque capacity with engine torque. Actual transmission disconnect clutch torque continues in the negative direction, and motor torque begins to decrease. Driver demand torque remains constant, and desired torque converter pump torque remains at its previous value.

[0082] At time tl4, the drive-line disconnect clutch is locked. Shortly thereafter, engine torque increases, and as the engine torque increases, the predicted drive-line disconnect clutch torque increases. In addition, as the engine torque increases, the actual drive-line disconnect clutch torque increases. In response to the drive-line disconnect clutch being locked, the desired torque converter pump wheel torque also increases. The driver demand torque remains constant and the engine speed matches the torque converter pump wheel speed. The drive-line disconnect clutch torque capacity continues to increase and it reaches a maximum value around time tl5.

[0083] Referring now to Figure 7 , a flowchart for operating a hybrid vehicle is shown. Figure 7 At least some portions of the methods of Figure 1 and Figure 2 may be incorporated as executable instructions stored in the non-transitory memory of the systems shown in Figure 7 Additionally, some portions of the methods of Figure 7 may occur in the physical world as operations or actions performed by a controller to transition the operational state of one or more devices. Some control parameters described herein can be determined by receiving inputs from previously described sensors and actuators. Figure 5 The methods of Figure 6 also provide the operational sequences shown in

[0084] At 702, the method 700 determines the engine speed (N) and the torque converter pump wheel speed (TN) through sensor inputs to the controller. In one example, the engine speed and the torque converter pump wheel speed can be determined by measuring the time interval between teeth of a gear. After determining the engine speed and the torque converter pump wheel speed, the method 700 proceeds to 704.

[0085] At 704, the method 700 estimates the drive-line disconnect clutch torque capacity. The drive-line disconnect clutch torque capacity is the amount of torque that the drive-line disconnect clutch can transfer without slip or with less than a predetermined amount of slip (e.g., less than 50 RPM of slip). In one example, the method 700 can estimate the drive-line disconnect clutch torque capacity (CP) as a function of force (x) to close the drive-line disconnect clutch. The function can be referenced by the force x, and the values in the function can be determined empirically. Alternatively, the drive-line disconnect clutch torque capacity (CP) can be determined as a function of the drive-line disconnect clutch position. The method 700 proceeds to 706.

[0086] At 706, method 700 estimates the net engine torque (e.g., the engine torque generated at the engine crankshaft minus the torque used to drive accessories coupled to the engine (alternator, power steering, etc.)). In one example, the net engine torque (ETOR) can be estimated based on a function (f) of engine airflow (AIR), engine speed (N), and engine fuel flow (FUEL). This function can be referenced by engine speed, engine airflow, and engine fuel flow. The function can be populated with empirically determined data, and the function outputs an engine torque value. In some examples, the engine torque value can be further adjusted in response to spark timing. For example, in response to the engine's current spark timing, the engine torque can be adjusted relative to the minimum spark timing of the optimal torque (MBT). Therefore, if the engine's current spark timing is delayed from the MBT spark timing, the estimated net engine torque can be reduced as a function of the spark timing delayed from the MBT spark timing. Method 700 proceeds to 708.

[0087] At point 708, method 700 estimates the amount of drivetrain disengagement clutch slip and drivetrain disengagement clutch excess torque capacity. In one example, drivetrain disengagement clutch slip is determined by the following equation:

[0088] DC 滑差 =N-TN

[0089] DC 滑差 Here, N is the slip of the transmission system's disengagement clutch, N is the engine speed, and TN is the torque converter pump impeller speed. The excess torque capacity of the transmission system's disengagement clutch can be determined by the following equation:

[0090] DC_ET=CP-ETOR

[0091] Where DC_ET is the excess torque of the transmission system's disengagement clutch, CP is the torque capacity of the transmission system's disengagement clutch, and ETOR is the net engine torque. Method 700 proceeds to 710.

[0092] At point 710, method 700 determines the engine torque weighting coefficient α1 and the transmission system disengagement clutch torque capacity weighting coefficient β1. In one example, these two coefficients can be determined by the following equation:

[0093] α1 = f1(DC_ET, DC) 滑差 )

[0094] β1 = f2(DC_ET, DC) 滑差 )

[0095] where f1 is a function or table of an empirically determined value of a1, which can range from 0 to one, f2 is a function or table of an empirically determined value of b1, which can range from -1 to 1, DC ET is a driveline disconnect clutch excess torque, and DC 滑差 is a driveline disconnect clutch slip. The method 700 proceeds to 712.

[0096] At 712, the method 700 determines a predicted driveline disconnect clutch torque. In one example, the predicted driveline disconnect clutch torque can be determined by the following equation:

[0097] DC 预测 = (a1 · ETOR) + (b1 · CP)

[0098] where DC 预测 is the predicted driveline disconnect clutch torque, a1 is an engine torque weighting coefficient, b1 is a driveline disconnect clutch torque capacity weighting coefficient, ETOR is a current net engine torque, and CP is a current driveline disconnect clutch torque capacity. The value of DC 预测 may be broadcast over the CAN to one or more controllers in the vehicle, such that the driveline torque actuators can be adjusted in response to the value of DC 预测 . The method 700 proceeds to 714.

[0099] At 714, the method 700 adjusts the driveline torque actuators in response to the value of DC 预测 . In one example, the motor torque is adjusted in response to the value of DC 预测 such that, during engine start-up, the driveline torque can remain substantially constant (e.g., vary by less than 10%). Additionally, the engine torque can be adjusted by adjusting the throttle position, fuel injection timing, spark timing, cam timing, or other torque actuators such that the driveline torque follows a desired trajectory. For example, if the predicted driveline disconnect clutch torque magnitude increases and the predicted driveline disconnect clutch torque is negative, the motor torque can be increased in the positive direction to maintain the driveline torque, thereby reducing driveline torque disturbance. The method 700 then exits.

[0100] In this way, the method 700 can predict the driveline disconnect clutch torque, such that driveline torque disturbance due to CAN latency can be mitigated. Additionally, the predicted driveline disconnect clutch torque can be used to adjust the engine torque during engine start-up and operation.

[0101] Thus, Figure 7The method of provides a vehicle operation method comprising: receiving sensor inputs to a controller; adjusting a driveline torque actuator in response to a driveline disconnect clutch torque, the driveline disconnect clutch torque based on an engine torque and a driveline disconnect clutch capacity, and wherein the engine torque is based on the sensor inputs. The method comprises: wherein the driveline disconnect clutch torque capacity is estimated, wherein the driveline disconnect clutch torque is predicted in response to the estimated engine torque and the estimated driveline disconnect clutch torque capacity, and wherein the engine torque is estimated in response to an engine speed, an engine air flow, and an engine fuel flow. The method comprises: wherein the driveline disconnect clutch torque capacity is an amount of torque that the driveline disconnect clutch is capable of mechanically transmitting without clutch slip. The method comprises: wherein clutch slip is a threshold speed at which a speed of a first side of the driveline disconnect clutch is greater than a speed of a second side of the driveline disconnect clutch. The method comprises: wherein the driveline torque actuator is an electric machine. The method comprises: wherein the driveline torque actuator is an engine throttle. The method comprises: wherein the driveline disconnect clutch is positioned in a driveline between an electric machine and an engine.

[0102] Figure 7 The method of also provides a vehicle operation method comprising: receiving sensor inputs to a controller; adjusting a driveline torque actuator in response to a driveline disconnect clutch torque, the driveline disconnect clutch torque responsive to operating the driveline disconnect clutch in at least one of a plurality of driveline disconnect clutch torque prediction zones. The method also comprises: estimating an engine torque from the sensor inputs; estimating a driveline disconnect clutch torque capacity; predicting the driveline disconnect clutch torque further in response to the estimated engine torque multiplied by a first weighting factor and the estimated driveline disconnect clutch torque capacity multiplied by a second weighting factor, the first and second weighting factors dependent on the plurality of driveline disconnect clutch torque prediction zones, and wherein the first weighting factor is a real number between zero and one. The method comprises: wherein the second weighting factor is a real number between negative one and one. The method also comprises adjusting the first and second weighting factors in response to the plurality of driveline disconnect clutch torque prediction zones. The method comprises: wherein the plurality of driveline disconnect clutch torque prediction zones comprises nine zones. The method also comprises predicting the driveline disconnect clutch torque by adding the estimated engine torque multiplied by the first weighting factor to the estimated driveline disconnect clutch torque capacity multiplied by the second weighting factor. The method comprises: wherein the driveline disconnect clutch is positioned in a driveline between an electric machine and an engine, and wherein the electric machine is positioned upstream of a transmission.

[0103] Note that the example 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 non-transitory memory and can be executed by control systems comprising controllers to control various engine hardware, in conjunction with various sensors, actuators, and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and so on. As such, the various acts, operations, and / or functions illustrated can be performed in the manner shown, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily restricted to that shown unless specifically stated. One of ordinary skill in the art will recognize that many of the acts, operations, and / or functions can be performed by one or more of the various engines, and that the conveying of information between the foregoing can be accomplished in either direction, and can use indirect routing. The descriptions, embodiments, examples, etc. are not meant to limit the scope of the claims in any manner, but are meant to provide illustration of the various embodiments to assist in the understanding of primarily the principles of the application. Furthermore, each example is believed to embody a general principle on which the examples are predicated. The application can be practiced with the specific details set forth or modifications, or with other elements and materials, components, methods, etc. comparable thereto, without departing from the spirit of the application within the scope of the claims. It is therefore desired that the embodiments of this application be defined by the scope of the claims rather than the description.

[0104] The following is a summary of the present specification. Many variations and modifications will occur to those skilled in the art upon consideration of the description herein. For example, I3, I4, I5, V6, V8, V10, and V12 engines operating in natural gas, gasoline, diesel, or alternative fuel configurations can benefit from the present specification.

[0105] According to the present application, a vehicle system is provided having: an electric machine; an engine; a drive line disconnect clutch mechanically coupled to the engine and the electric machine; and one or more controllers comprising executable instructions stored in non-transitory memory to adjust an engine torque actuator in response to a drive line disconnect clutch torque, the drive line disconnect clutch torque based on an engine torque and a drive line disconnect clutch torque capacity.

[0106] According to one embodiment, the drive line disconnect clutch is positioned in the drive line between the engine and the electric machine.

[0107] According to one embodiment, the present application features further having a fixed-ratio transmission positioned in the drive line downstream of the electric machine.

[0108] According to one embodiment, the application features further having additional instructions for adjusting the first weighting factor and the second weighting factor in response to a plurality of zones of a driveline disconnect clutch capacity versus driveline disconnect clutch slip map.

[0109] According to one embodiment, the plurality of zones includes nine zones.

[0110] According to one embodiment, the torque actuator is the electric machine.

[0111] According to the application, a vehicle operation method has the steps of: receiving sensor inputs to a controller; adjusting a driveline torque actuator in response to a driveline disconnect clutch torque, the driveline disconnect clutch torque based on an engine torque and a driveline disconnect clutch capacity, wherein the engine torque is based on the sensor inputs.

[0112] According to one embodiment, a vehicle operation method is provided, wherein the driveline disconnect clutch torque capacity is estimated, wherein the driveline disconnect clutch torque is predicted in response to the estimated engine torque and the estimated driveline disconnect clutch torque capacity, and wherein the engine torque is estimated in response to engine speed, engine air flow, and engine fuel flow.

[0113] According to one embodiment, a vehicle operation method is provided, wherein the driveline disconnect clutch torque capacity is an amount of torque that the driveline disconnect clutch is capable of mechanically transmitting without clutch slip.

[0114] According to one embodiment, a vehicle operation method is provided, wherein the clutch slip is a threshold speed at which a speed of a first side of the driveline disconnect clutch is greater than a speed of a second side of the driveline disconnect clutch.

[0115] According to one embodiment, a vehicle operation method is provided, wherein the driveline torque actuator is an electric machine.

[0116] According to one embodiment, a vehicle operation method is provided, wherein the driveline torque actuator is an engine throttle.

[0117] According to one embodiment, a vehicle operation method is provided, wherein the driveline disconnect clutch is positioned in the driveline between an electric machine and an engine.

[0118] According to the application, a vehicle operation method includes: receiving sensor inputs to a controller; adjusting a driveline torque actuator in response to a driveline disconnect clutch torque, the driveline disconnect clutch torque in response to operating the driveline disconnect clutch in at least one of a plurality of driveline disconnect clutch torque prediction zones.

[0119] According to one embodiment, there is provided a method of operating a vehicle by: estimating engine torque from said sensor input; estimating driveline disconnect clutch torque capacity; predicting said driveline disconnect clutch torque further in response to said estimated engine torque multiplied by a first weighting factor and said estimated driveline disconnect clutch torque capacity multiplied by a second weighting factor, said first and second weighting factors depending on said plurality of driveline disconnect clutch torque prediction zones, and wherein said first weighting factor is a real number between zero and one.

[0120] According to one embodiment, there is provided a method of operating a vehicle, wherein said second weighting factor is a real number between negative one and one.

[0121] According to one embodiment, there is provided a method of operating a vehicle, said method adjusting said first and second weighting factors in response to said plurality of driveline disconnect clutch torque prediction zones.

[0122] According to one embodiment, a method of operating a vehicle comprises: said plurality of driveline disconnect clutch torque prediction zones comprising nine zones.

[0123] According to one embodiment, there is provided a method of operating a vehicle, said method predicting said driveline disconnect clutch torque by adding said estimated engine torque multiplied by said first weighting factor to said estimated driveline disconnect clutch torque capacity multiplied by said second weighting factor.

[0124] According to one embodiment, a method of operating a vehicle comprises: said driveline disconnect clutch being positioned in a driveline between an electric machine and an engine, and wherein said electric machine is positioned upstream of a transmission.

Claims

1. A vehicle system comprising: Electric motor; engine; The transmission system has a disengagement clutch that is mechanically connected to the engine and the motor; and One or more controllers include executable instructions stored in a non-transient memory to regulate an engine torque actuator in response to a drivetrain disengagement clutch torque based on engine torque and drivetrain disengagement clutch torque capacity; Additional instructions are provided to adjust a first weighting factor applied to the engine torque and a second weighting factor applied to the transmission system disconnect clutch torque capacity in response to multiple zones of the transmission system disconnect clutch slip map.

2. The system of claim 1, wherein the drivetrain disengagement clutch is positioned in the drivetrain between the engine and the motor.

3. The system of claim 2 further includes a fixed-ratio transmission, the fixed-ratio transmission being positioned downstream of the motor in the transmission system.

4. The system of claim 1, wherein the plurality of zones comprises nine zones.

5. The system of claim 1, wherein the torque actuator is the motor.

6. A vehicle operation method, comprising: The sensor input is received by the controller; The drivetrain torque actuator is adjusted in response to the drivetrain disengagement clutch torque, which is based on engine torque and drivetrain disengagement clutch torque capacity; wherein a first weighting factor applied to the engine torque and a second weighting factor applied to the drivetrain disengagement clutch torque capacity are adjusted in response to multiple regions of the drivetrain disengagement clutch slip map. The engine torque is based on the sensor input.

7. The method of claim 6, wherein the torque capacity of the drivetrain disengagement clutch is estimated, wherein the torque of the drivetrain disengagement clutch is predicted in response to the estimated engine torque and the estimated torque capacity of the drivetrain disengagement clutch, and wherein the engine torque is estimated in response to engine speed, engine airflow, and engine fuelflow.

8. The method of claim 6, wherein the torque capacity of the transmission system separation clutch is the amount of torque that the transmission system separation clutch can mechanically transmit without clutch slippage.

9. The method of claim 8, wherein clutch slippage is a threshold speed at which the rotational speed of the first side of the transmission system disengagement clutch is greater than the rotational speed of the second side of the transmission system disengagement clutch.

10. The method of claim 6, wherein the transmission torque actuator is an electric motor.

11. The method of claim 6, wherein the transmission torque actuator is an engine throttle valve.

12. The method of claim 6, wherein the drivetrain disengagement clutch is positioned in the drivetrain between the motor and the engine.

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