Method and system for adapting driveline disconnect clutch operation

Abstract

The present disclosure provides a method and system for adapting the operation of a powertrain disconnect clutch. A system and method for operating a hybrid powertrain system including an engine and a motor / generator are described. The system and method provide a means of pre-positioning the engine to improve the range of adaptation of the powertrain disconnect clutch transfer function. In one example, the engine is positioned so that the torque required to rotate the engine exceeds a threshold torque.

Description

Technical Field

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

[0002] Background and Summary of the Invention

[0003] A hybrid vehicle may include a powertrain disconnect clutch for selectively engaging and disengaging the engine from the electric machine and transmission. The powertrain disconnect clutch may be disengaged during periods of low driver demand when the electric machine is able to provide the driver demand torque. The powertrain disconnect clutch may be closed in response to a driver demand torque that is greater than the electric machine's capacity or in response to a low battery state of charge. The powertrain disconnect clutch may be commanded to provide a specific torque capacity during the powertrain disconnect clutch closing process so that vehicle occupants may not feel a large torque disturbance when the powertrain disconnect clutch closes. The powertrain disconnect clutch torque capacity may be a function of the applied pressure applied to close the powertrain disconnect clutch. However, the relationship between the applied pressure and torque capacity of the powertrain disconnect clutch may vary from vehicle to vehicle. Furthermore, the relationship between the applied pressure and torque capacity of the powertrain disconnect clutch may change as the vehicle ages. Therefore, if the powertrain disconnect clutch is closed based on an applied pressure to torque capacity relationship developed by the vehicle manufacturer, and this applied pressure to torque capacity relationship differs from the applied pressure to torque capacity relationship of a particular vehicle, a powertrain torque disturbance may occur in that particular vehicle. Therefore, it is desirable to operate the powertrain disconnect clutch of a particular vehicle based on the applied pressure to torque capacity relationship of the particular vehicle.

[0004] The inventors herein have recognized the aforementioned problems and have developed a vehicle operating method that includes requesting an adjustment of an effort to clutch torque capacity relationship; adjusting an engine stopping position in response to the request; and adjusting the effort to clutch torque capacity relationship.

[0005] By adjusting the stopping position of the engine in response to a request to adjust the force-to-clutch capacity relationship, a technical result of increasing the torque required for engine rotation can be provided, thereby allowing a wider range of force-to-clutch torque capacity relationships to be adjusted. Specifically, the engine is coupled to one side of a transmission disconnect clutch, and the other side of the transmission disconnect clutch is coupled to an electric motor. The engine can be operated as a grounding device, which restricts one side of the transmission disconnect clutch from movement as long as the amount of torque transmitted via the transmission disconnect clutch does not exceed the torque required for engine rotation. If the engine stopping position is adjusted to a position where a higher torque is required to rotate the engine, the force-to-clutch torque capacity can be adapted from zero torque all the way up to the torque required for engine rotation. In this way, the range of adaptation of the force-to-clutch torque capacity relationship can be increased to provide a more complete adaptation of the transmission disconnect clutch transfer function.

[0006] The present disclosure can provide several advantages. For example, the method can provide an improved prediction of the driveline disconnect clutch torque, allowing for improved driveline torque compensation. Furthermore, the method can be provided without the need for additional engine sensors or actuators. Furthermore, the method can improve driveline disconnect clutch transfer function adaptation.

[0007] The above advantages and other advantages and features of the present specification will become apparent from the following "Detailed Description" when read alone or in conjunction with the accompanying drawings.

[0008] It should be understood that the above Summary is provided to introduce in simplified form a series of concepts that will be further described in the Detailed Description. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is solely 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

[0009] Advantages described herein will be more fully understood by reading the examples of embodiments herein referred to as detailed description when read alone or with reference to the accompanying drawings, in which:

[0010] Figure 1 It is a schematic diagram of the engine;

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

[0012] Figure 3A is a schematic diagram of an example fuel pump;

[0013] Figure 3Bis a graph illustrating example engine stop position relative to engine position and torque required for fuel pump rotation;

[0014] Figure 4 is a graph illustrating an example driveline disconnect clutch adaptation sequence;

[0015] Figure 5 is a graph of an example transmission system disconnect clutch force versus clutch torque capacity; and

[0016] Figure 6 An example flow chart of a method for operating a powertrain and adapting a powertrain disconnect clutch effort to clutch torque capacity relationship is shown. DETAILED DESCRIPTION

[0017] This specification relates to adapting the powertrain disconnect clutch force versus clutch torque capacity relationship for a hybrid vehicle. The powertrain disconnect clutch transfer function describing the force versus clutch torque capacity relationship may be adapted or adjusted from time to time to improve powertrain disconnect clutch control. The powertrain disconnect clutch may be coupled to an engine, such as Figure 1 The engine shown. A transmission disconnect clutch may also be included in a hybrid vehicle transmission or drivetrain, such as Figure 2 The torque required to turn the engine (e.g., the amount of torque that needs to be applied to a stopped engine before the engine will rotate, excluding the torque to spin the engine's mechanically driven fuel pump) can be increased before adapting the transmission disconnect clutch transfer function, which allows a wider range of forces to be mapped. Figure 3A An example fuel pump is shown having a fuel pump rotation required torque (e.g., the amount of torque that needs to be applied to a stopped fuel pump before the fuel pump will rotate, not including the torque to rotate the engine without the fuel pump) that is sensitive to engine position. Figure 3B It shows how engine position can be adjusted based on fuel pump position, which is related to the torque required to rotate the fuel pump. Figure 4 An example transmission disengagement clutch adaptation sequence is shown in . Figure 5 The relationship between the force of the transmission disconnect clutch and the torque capacity of the transmission disconnect clutch is shown in FIG. Figure 6 A method for operating a transmission and adapting the relationship between the force and the torque capacity of the transmission's disconnect clutch is shown in FIG.

[0018] Reference Figure 1 Internal combustion engine 10, comprising a plurality of cylinders, is controlled by electronic engine controller 12, wherein one cylinder is Figure 1. Engine 10 is comprised of cylinder head 35 and cylinder block 33, which includes combustion chamber 30 and cylinder walls 32. Piston 36 is positioned therein and reciprocates via connection to crankshaft 40. Combustion chamber 30 is shown communicating with intake manifold 44 and exhaust manifold 48 via respective intake valve 52 and exhaust valve 54. Each intake valve and exhaust valve may be operated by an intake cam 51 and an exhaust cam 53. The position of intake cam 51 may be determined by intake cam sensor 55. The position of exhaust cam 53 may be determined by exhaust cam sensor 57. Intake valve 52 may be selectively activated and deactivated by valve activation device 59. Exhaust valve 54 may be selectively activated and deactivated by valve activation device 58. Valve activation devices 58 and 59 may be electromechanical devices.

[0019] Fuel injector 66 is shown positioned to inject fuel directly into cylinder 30, which is known to those skilled in the art as direct injection. Fuel injector 66 delivers liquid fuel in proportion to the pulse width from controller 12. Fuel is delivered to fuel injector 66 by a fuel system including fuel tank 93, mechanical high-pressure fuel pump 91, and low-pressure fuel pump 92.

[0020] In addition, intake manifold 44 is shown as being in communication with turbocharger compressor 162 and engine air intake 42. In other examples, compressor 162 may be a supercharger compressor. Shaft 161 mechanically couples turbocharger turbine 164 to turbocharger compressor 162. Optional electronic throttle 62 adjusts the position of throttle plate 64 to control air flow from compressor 162 to intake manifold 44. The pressure in boost chamber 45 may be referred to as the throttle inlet pressure because the inlet of throttle 62 is within boost chamber 45. The throttle outlet is located in intake manifold 44. In some examples, throttle 62 and throttle plate 64 may be located between intake valve 52 and intake manifold 44 so that throttle 62 is a port throttle. Compressor recirculation valve 47 may be selectively adjusted to a plurality of positions between fully open and fully closed. Wastegate 163 may be adjusted via controller 12 to allow exhaust to selectively bypass turbine 164 to control the speed of compressor 162. Air filter 43 cleans air entering engine air intake 42.

[0021] Distributorless ignition system 88 provides an ignition spark to combustion chamber 30 via spark plug 92 in response to controller 12. Universal Exhaust Gas Oxygen (UEGO) sensor 126 is shown coupled to exhaust manifold 48 upstream of catalytic converter 70. Alternatively, a two-state exhaust gas oxygen sensor may be used in place of UEGO sensor 126.

[0022] In one example, converter 70 may include multiple catalyst bricks. In another example, multiple emission control devices may be used, each having multiple bricks. In one example, converter 70 may be a three-way catalyst.

[0023] The controller 12 Figure 1 1 is a conventional microcomputer including: a microprocessor unit 102, input / output ports 104, read-only memory 106 (e.g., non-volatile memory), random access memory 108, keep-alive memory 110, and a conventional data bus. In addition to those signals previously discussed, controller 12 is shown receiving various signals from sensors coupled to engine 10, including: engine coolant temperature (ECT) from temperature sensor 112 coupled to coolant jacket 114; position sensor 134 coupled to accelerator pedal 130 for sensing force applied by a person's foot 132; position sensor 154 coupled to brake pedal 150 for sensing force applied by foot 152; engine manifold pressure (MAP) measurement from pressure sensor 122 coupled to intake manifold 44; an engine position sensor such as Hall effect sensor 118 sensing the position of crankshaft 40; a measurement of air mass entering the engine from sensor 120; and a throttle position measurement from sensor 68. Barometric pressure (sensor not shown) may also be sensed for processing by controller 12. In a preferred aspect of the present disclosure, engine position sensor 118 produces a predetermined number of equally spaced pulses every revolution of the crankshaft from which engine speed (RPM) can be determined. Engine speed at sensor 118 is equal to Figure 2 The speed of the first side 235 of the transmission disconnect clutch 236 shown in FIG. Figure 2 The sensor 288 shown in Figure 1 estimates the force used to close the transmission disconnect clutch 236. The sensor 288 can be a current sensor, a pressure sensor, or a position sensor, depending on the type of force used to close the transmission disconnect clutch 236.

[0024] During operation, each cylinder within engine 10 typically undergoes a four-stroke cycle, including the intake stroke, compression stroke, expansion stroke, and exhaust stroke. During the intake stroke, exhaust valve 54 is typically closed and intake valve 52 is open. Air is introduced into combustion chamber 30 via intake manifold 44, and piston 36 moves to the bottom of the cylinder so as 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 (e.g., when combustion chamber 30 is at its largest volume) is typically referred to by those of skill in the art as bottom dead center (BDC).

[0025] During the compression stroke, intake valve 52 and exhaust valve 54 are closed. Piston 36 moves toward the cylinder head so as to compress the air within combustion chamber 30. The point at which piston 36 is at the end of its stroke and closest to the cylinder head (e.g. when combustion chamber 30 is at its smallest volume) is typically referred to by those of skill in the art as top dead center (TDC). In a process herein referred to as injection, fuel is introduced into the combustion chamber. In a process herein referred to as ignition, the injected fuel is ignited by known ignition means, such as spark plug 92, causing combustion.

[0026] During the expansion stroke, the expanding gases push piston 36 back to BDC. Crankshaft 40 converts the piston's motion into rotational torque of the rotating 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 only as an example, and the intake and exhaust valve opening and / or closing timings may be varied, for example, to provide positive or negative valve overlap, late intake valve closing, or various other examples.

[0027] Figure 2 is a block diagram of a vehicle 225 including a powertrain or driveline 200 . Figure 2 The powertrain system includes Figure 1 10 is shown in FIG. Powertrain system 200 is shown to include a vehicle system controller 255, engine controller 12, motor controller 252, transmission controller 254, energy storage device controller 253, and brake controller 250. The controllers can communicate via 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, and diagnostic information (e.g., information about transmission degradation, engine degradation, motor degradation, and brake degradation). In addition, the vehicle system controller can provide commands to engine controller 12, motor controller 252, transmission controller 254, and brake controller 250 to implement driver input requests and other requests based on vehicle operating conditions. Status information can be provided to the driver via a human / machine interface 256 (e.g., a keyboard and display).

[0028] 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 requesting a first braking torque from the motor controller 252 and a second braking torque from the brake controller 250, the first torque and the second torque providing the desired braking torque at the wheel 216.

[0029] In other examples, the powertrain control device may be configured differently from Figure 2 For example, a single controller may replace the vehicle system controller 255 , the engine controller 12 , the motor controller 252 , the transmission controller 254 , and the brake controller 250 .

[0030] In this example, the powertrain 200 can be powered by the engine 10 and the electric machine 240. The engine 10 can be used Figure 1 , or via an integrated starter / generator (ISG) 240. ISG 240 (e.g., a high-voltage (operating at greater than 30 volts) electric motor) may also be referred to as an electric machine, motor, and / or generator. Additionally, the torque of engine 10 may be adjusted via torque actuators 204, such as fuel injectors, a throttle, or the like.

[0031] The 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 as being mechanically coupled to the ISG input shaft 237.

[0032] Belt starter generator (BISG) 266 is mechanically coupled to exhaust cam 53 of engine 10 via belt 281. Exhaust cam 53 is coupled to crankshaft 40 via chain 280. When engine 10 can reverse rotation via BISG 266, active belt tensioner 267 can be selectively activated via controller 12 to reduce belt compliance. BISG 266 can be operated to provide torque to powertrain 200 or, in regenerative mode, convert powertrain torque into electrical energy for storage in 12-volt battery 264. BISG 266 can provide torque to the crankshaft and start engine 10. BISG 266 has a lower output torque capacity than ISG 240. BISG 266 is electrically coupled to 12-volt battery 264 and electrical disconnect switch 260. Electrical disconnect switch 260 can disconnect BISG 266 and 12-volt battery 264 from low-voltage bus 262. Battery 264 can supply electrical power to rotate BISG 266. Auxiliary battery 263 can supply power to auxiliary devices 265 (eg, electric steering assist, window motors, etc.) DC / DC converter 261 can reduce the voltage of energy storage device 275 to supply power to low voltage bus 262 and auxiliary battery 263 .

[0033] The ISG 240 can be operated to provide torque to the powertrain 200 or, in a regenerative mode, convert the powertrain torque into electrical energy that is stored in the electrical energy storage device 275. Figure 1 Belt-driven starter-generator 266 is shown, which has a higher output torque capacity. Additionally, ISG 240 directly drives or is directly driven by driveline 200. No belts, gears, or chains couple ISG 240 to driveline 200. Instead, ISG 240 rotates at the same rate as driveline 200. Electrical energy storage device 275 (e.g., a high-voltage battery or power source) can be a battery, capacitor, or inductor. The downstream side of ISG 240 is mechanically coupled to impeller 285 of torque converter 206 via shaft 241. Speed ​​sensor 273 senses the speed of the torque converter impeller, which is equal to the speed of second side 234 of driveline disconnect clutch 236. The upstream side of ISG 240 is mechanically coupled to disconnect clutch 236. ISG 240 can provide positive or negative torque to driveline 200 by operating as a motor or generator, as commanded by motor controller 252.

[0034] The torque converter 206 includes a turbine 286 to output torque to the 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 lockup clutch 212 (TCC). When the TCC is locked, torque is transferred directly from the impeller 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.

[0035] When the torque converter lockup clutch 212 is fully disengaged, the torque converter 206 transmits the engine torque to the automatic transmission 208 via fluid transfer between the torque converter turbine 286 and the torque converter pump 285, thereby achieving torque multiplication. Conversely, when the torque converter lockup clutch 212 is fully engaged, the engine output torque is directly transmitted to the input shaft (not shown) of the transmission 208 via the torque converter clutch. Alternatively, the torque converter lockup clutch 212 can be partially engaged, thereby enabling the amount of torque directly transmitted 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 lockup clutch in response to various engine operating conditions or based on the driver's engine operation request.

[0036] Automatic transmission 208 includes range clutches (e.g., ranges 1 through 10) 211 and forward clutch 210. Automatic transmission 208 is a fixed-ratio transmission. Range clutches 211 and forward clutch 210 can be selectively engaged to change the ratio of the actual total number of revolutions of input shaft 270 to the actual total number of revolutions of wheels 216. Range clutch 211 can be engaged or disengaged by regulating the fluid supplied to the clutch via shift control solenoid valve 209. Torque output from automatic transmission 208 can also be transmitted to wheels 216 via output shaft 260 to propel the vehicle. Specifically, automatic transmission 208 can transmit input drive torque at input shaft 270 and then transmit output drive torque to wheels 216 in response to vehicle driving conditions. Transmission controller 254 selectively activates or engages TCC 212, range clutches 211, and forward clutch 210. The transmission controller also selectively deactivates or disengages TCC 212, range clutches 211, and forward clutch 210.

[0037] Additionally, frictional forces can be applied to wheels 216 by engaging friction wheel brakes 218. In one example, friction wheel brakes 218 can be engaged in response to the driver pressing his / her foot on a brake pedal (not shown) and / or in response to a command within brake controller 250. Additionally, brake controller 250 can apply brakes 218 in response to information and / or a request from vehicle system controller 255. In a similar manner, frictional forces on wheels 216 can be reduced by disengaging wheel brakes 218 in response to the driver releasing his / her foot from the brake pedal, a brake controller command, and / or a vehicle system controller command and / or information. For example, vehicle brakes can apply frictional forces to wheels 216 via controller 250 as part of an automatic engine stop procedure.

[0038] In response to a request to accelerate vehicle 225, the vehicle system controller may obtain a driver demand torque or power request from the accelerator pedal or other device. Vehicle system controller 255 then distributes a portion of the requested driver demand torque to the engine and the remainder to ISG 240. Vehicle system controller 255 requests engine torque from engine controller 12 and ISG torque from motor controller 252. If the sum of the ISG torque and the engine torque is less than the transmission input torque limit (e.g., a threshold that should not be exceeded), the torque is delivered to torque converter 206, which then transmits at least a portion of the requested torque to transmission input shaft 270. Transmission controller 254 selectively locks torque converter clutch 212 and engages a gear via range clutch 211 in response to a shift schedule and TCC locking schedule, which may be based on input shaft torque and vehicle speed. In some cases, when charging of electrical energy storage device 275 may be necessary, a charging torque (e.g., negative ISG torque) may be requested in the presence of a non-zero driver demand torque. The vehicle system controller 255 may request increased engine torque to overcome the charging torque to meet the driver demand torque.

[0039] In response to a request to decelerate vehicle 225 and provide regenerative braking, the vehicle system controller may provide a negative desired wheel torque based on vehicle speed and brake pedal position. The vehicle system controller 255 then distributes a portion of the negative desired wheel torque to ISG 240 (e.g., desired drivetrain wheel torque) and the remainder to friction brakes 218 (e.g., desired friction brake wheel torque). Additionally, the vehicle system controller may notify transmission controller 254 that the vehicle is in regenerative braking mode, causing transmission controller 254 to shift gears 211 based on a unique shift schedule to improve regeneration efficiency. While ISG 240 supplies negative torque to transmission input shaft 270, the negative torque provided by ISG 240 may be limited by transmission controller 254, which outputs a transmission input shaft negative torque limit (e.g., a threshold that should not be exceeded). Furthermore, based on the operating conditions of the electrical energy storage device 275, the vehicle system controller 255 or motor controller 252 may limit the negative torque of ISG 240 (e.g., constraining it to less than a negative threshold torque). Any portion of the desired negative wheel torque that may not be provided by the ISG 240 due to transmission or ISG limitations may be distributed to the friction brakes 218 so that the desired wheel torque is provided by a combination of the negative wheel torques from the friction brakes 218 and the ISG 240 .

[0040] Thus, torque control of various powertrain components may be monitored by vehicle system controller 255 , with local torque control of engine 10 , transmission 208 , motor 240 , and brake 218 provided via engine controller 12 , motor controller 252 , transmission controller 254 , and brake controller 250 .

[0041] As an example, engine torque output can be controlled by adjusting a combination of spark timing, fuel pulse width, fuel pulse timing, and / or air intake by controlling throttle opening and / or valve timing, valve lift, and boost pressure in a turbocharged or supercharged engine. In the case of a diesel engine, controller 12 can control engine torque output by controlling a combination of fuel pulse width, fuel pulse timing, and air intake. In all cases, engine control can be performed on a cylinder-by-cylinder basis to control engine torque output.

[0042] As is known in the art, motor controller 252 may control torque output and electrical power generation from ISG 240 by regulating current flow into and out of the field and / or armature windings of the ISG.

[0043] Transmission controller 254 receives transmission input shaft position or torque converter turbine speed via position sensor 271. Transmission controller 254 can convert transmission input shaft position into input shaft speed by taking the derivative of the signal from position sensor 271 or counting a number of pulses with a known angular distance within a predetermined time interval. Transmission controller 254 can receive transmission output shaft torque from torque sensor 272. Alternatively, sensor 272 can be a position sensor or a torque and position sensor. If sensor 272 is a position sensor, controller 254 can count shaft position pulses within a predetermined time interval to determine transmission output shaft speed. Transmission controller 254 can also take the derivative of the transmission output shaft speed to determine transmission output shaft acceleration.

[0044] The brake controller 250 receives wheel speed information through the wheel speed sensor 221 and receives a braking request from the vehicle system controller 255. The brake controller 250 may also receive a braking request from the vehicle system controller 255 directly or through the CAN 299. Figure 1 The brake pedal sensor 154 shown 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 anti-skid and vehicle stability braking to improve vehicle braking and stability. To this end, the brake controller 250 can provide a wheel torque limit (e.g., a threshold negative wheel torque that should not be exceeded) to the vehicle system controller 255 so that negative ISG torque does not cause the wheel torque limit to be exceeded. For example, if the controller 250 gives a negative wheel torque limit of 50Nm, the ISG torque is adjusted to provide a negative torque of less than 50Nm (e.g., 49Nm) at the wheel, including taking into account the transmission gear connection.

[0045] Now refer to Figure 3A , shows a detailed view of the mechanically driven fuel pump 91. The inlet 303 of the direct injection fuel pump compression chamber 308 is connected to a low pressure fuel pump (e.g., Figure 292 shown in FIG. Fuel is supplied via a pump (e.g., a pump cam 310) as it passes through the mechanically driven fuel pump 91. The fuel may be pressurized as it passes through the mechanically driven fuel pump 91 and supplied to the fuel rail via the pump outlet 304. In the depicted example, the mechanically driven fuel pump 91 may be a mechanically driven displacement pump comprising an injection pump cylinder 350, an injection pump piston 306, an injection pump piston rod 320, a pump compression chamber 308 (also referred to herein as the compression chamber), and a step chamber 318. The injection pump piston 306 comprises a top portion 305 and a bottom portion 307. The step chamber and the compression chamber may comprise cavities located on opposite sides of the pump piston. In one example, the injection pump piston 306 in the mechanically driven fuel pump 91 is driven via a rod 320 by a cam lobe 310. The exhaust camshaft 53 includes four cam lobes 310 and completes one rotation for every two engine crankshaft revolutions. In other examples, the cam lobes 310 may be fewer. The cam lobes 310 rotate as the exhaust camshaft 53 rotates.

[0046] A solenoid-activated relief valve 312 (e.g., a solenoid-activated inlet check valve) can be coupled to the pump inlet 303. The controller 12 can be configured to regulate fuel flow through the solenoid-activated relief valve 312 by energizing or de-energizing the solenoid valve (based on the solenoid valve configuration) in synchronization with the driving of the exhaust camshaft 53 and the cam lobe 310. The relief valve 312 can also be energized independently of the exhaust camshaft 53 and the cam lobe 310. Thus, the solenoid-activated relief valve 312 can operate in at least two modes. In a first mode, the solenoid-activated relief valve 312 is positioned within the inlet 303 to limit (e.g., inhibit) the amount of fuel that travels upstream of the solenoid-activated relief valve 312 and exits the inlet 303. In contrast, in a second mode, the solenoid-activated relief valve 312 is effectively disabled, and fuel can travel upstream and downstream of the solenoid-activated relief valve 312.

[0047] In this way, the solenoid-activated relief valve 312 can regulate the mass of fuel compressed into the mechanically driven fuel pump 91. In one example, the controller 12 can adjust the closing timing of the solenoid-activated relief valve 312 to regulate the mass of fuel compressed. For example, a later solenoid-activated relief valve closing time (e.g., 20 degrees before the piston 306 reaches top dead center compression stroke) can reduce the amount of fuel mass drawn into the compression chamber 308, while an earlier solenoid-activated relief valve closing time (e.g., 140 degrees before the piston 306 reaches top dead center compression stroke) can increase the amount of fuel mass drawn into the pump, thereby increasing the torque required to rotate the mechanically driven fuel pump 91. The opening and closing timing of the solenoid-activated relief valve can be coordinated with the stroke timing of the mechanically driven fuel pump 91. Additionally, by allowing a greater amount of fuel to enter the compression chamber 308 by adjusting the opening and closing times of the solenoid activated relief valve 312 , the torque required to turn the mechanically driven fuel pump 91 may be increased.

[0048] Conduit 399 allows fuel to reach solenoid-operated check valve 312, allowing solenoid-operated check valve 312 to adjust the amount of fuel being pumped to regulate the fuel pressure in the high-pressure fuel rail. Injection pump piston 306 reciprocates up and down in cylinder 350. When piston 306 moves in a direction that reduces the volume of compression chamber 308, mechanically driven fuel pump 91 is in a compression stroke. When injection pump piston 306 moves in a direction that increases the volume of compression chamber 308, mechanically driven fuel pump 91 is in a suction stroke.

[0049] A forward flow outlet check valve 316 may be coupled downstream of the outlet 304 of the compression chamber 308. The outlet check valve 316 opens to allow fuel to flow from the compression chamber outlet 304 into the fuel rail only when the pressure at the outlet of the mechanically driven fuel pump 91 (e.g., the compression chamber outlet pressure) is higher than the fuel rail pressure.

[0050] therefore, Figures 1 to 3AA system is provided for a vehicle system comprising: a motor; an engine including a mechanically driven fuel pump; a transmission disconnect clutch mechanically coupled to the engine and the motor; a belt drive starter generator mechanically coupled to the engine; and a controller including executable instructions stored in a non-volatile memory, the executable instructions causing the controller to adjust the engine to a stopped position based on the position of the fuel pump in response to a request to adjust the relationship between the force and clutch torque capacity of the transmission disconnect clutch. The system also includes instructions to operate the motor in a speed control mode in response to the request. The system includes the controller generating the request. The system also includes additional instructions to incrementally increase the force of the transmission disconnect clutch in response to the request. The system also includes additional instructions to adjust the engine to a stopped position via the belt drive starter generator. The system also includes additional instructions to adjust the position of a fuel pump relief valve in response to the request.

[0051] Now refer to Figure 3B , shows a graph illustrating an example engine stop position based on engine position and mechanically driven fuel pump position. The engine stop position can be adjusted based on Figure 6 The method through Figures 1 to 3A In addition, Figures 1 to 3A The system can be operated via instructions stored in the controller memory Figure 3B The engine is operated under the conditions described. The engine rotates from the engine position on the left side of the graph to the engine position on the right side of the graph.

[0052] from Figure 3B The first graph from the top plots the piston position of cylinder number one versus the engine crankshaft position. The vertical axis represents the position of the piston of cylinder number one. The horizontal axis represents engine position, with 0 crankshaft degrees representing the top dead center compression stroke of cylinder number one. The stroke abbreviations for cylinder number one are Exh. (exhaust stroke), Int. (intake stroke), Com. (compression stroke), and Pow. (power or expansion stroke). Curve 350 represents the position of the piston of cylinder number one.

[0053] from Figure 3BThe second graph from the top is a graph of torque required to rotate the engine versus engine position. The torque used to rotate or spin the engine increases in the direction of the vertical axis. The vertical axis represents the torque required to rotate the engine. The horizontal axis represents engine position, where 0 crankshaft degrees is the top dead center compression stroke of cylinder number one. Curve 352 represents the torque to rotate the engine. Horizontal line 360 ​​represents an upper limit where the engine can be stopped and torque can be removed from the engine without the engine rotating after the torque is removed from the engine. Horizontal line 362 represents a lower limit where the engine can be stopped and torque can be removed from the engine without the engine rotating after the torque is removed from the engine. If the engine is stopped at a crankshaft angle where trace 352 is above horizontal line 360 ​​or below horizontal line 362, the engine may rotate.

[0054] from Figure 3B The third graph at the top of the diagram plots fuel pump torque required versus engine crankshaft position. The vertical axis represents fuel pump torque required, with torque increasing in the direction of the vertical axis. The horizontal axis represents engine position, with 0 crankshaft degrees representing top dead center (TDC) compression stroke on cylinder number one. Curve 354 represents the engine fuel pump torque required.

[0055] If the engine is stopped at vertical line 398, the torque required to rotate the engine is not at its highest level because the torque required to rotate the fuel pump is low at vertical line 398. The low torque required to rotate the fuel pump at vertical line 398 is because the fuel pump has already passed the cam lobe peak position and its lift is decreasing, thus reducing the torque required to rotate the fuel pump. However, by rotating the engine to the position indicated by vertical line 399 via BISG 266, the torque required to rotate the engine can be increased. As the engine rotates from position 398 to position 399, the torque required to rotate the engine decreases and then increases. Similarly, the torque required to rotate the engine fuel pump decreases and then increases. At position 399, where the engine will not move forward or backward after torque from BISG 266 or ISG 240 is no longer applied to engine 10, the torque required to rotate the engine is maximum, and the torque required to rotate the fuel pump is maximum. Therefore, the torque required to rotate the engine and fuel pump is maximum at position 399, where the engine will not rotate when torque applied to the engine is released. Therefore, the torque required for engine rotation is a function of both engine position and fuel pump position. In addition, the torque required for engine and fuel pump rotation can be adjusted via rotating the engine and parking the engine at a specific engine position.

[0056] Now refer to Figure 4 , shows a graph of an example transmission system disconnect clutch transfer function adaptation sequence. Figures 1 to 3ASystem coordination Figure 6 Methods to provide Figure 4 sequence. Figure 4 The graphs of are time aligned and they occur simultaneously. The vertical lines from time t0 to t4 are the times of interest in the sequence. Figure 1 and Figure 2 The controller may include Figure 4 Instructions for operating the powertrain under the conditions described and shown.

[0057] Figure 4 The first graph is a graph of engine operating state versus time. The vertical axis represents engine operating state, and when trace 402 is at a higher level near the vertical axis arrow, the engine is operating. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Trace 402 represents the engine operating state.

[0058] Figure 4 The second graph is a graph of engine torque (torque required to rotate the engine) versus time. The vertical axis represents engine torque, and engine torque increases in the direction of the vertical axis arrow. Trace 404 represents engine torque. The horizontal axis represents time, and time increases from the left side of the graph to the right side.

[0059] Figure 4 The third graph is a graph of fuel pump torque (torque required to rotate the fuel pump) versus time. The vertical axis represents fuel pump torque, and the torque required to rotate the fuel pump increases in the direction of the vertical axis arrow. Trace 406 represents the torque required to rotate the fuel pump. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0060] Figure 4 The fourth graph is a graph of the state of the electrical isolation switch 260 versus time. The vertical axis represents the state of the electrical isolation switch, and when trace 408 is at a higher level near the vertical axis arrow, the electrical isolation switch is closed (allowing current to flow through the isolation switch). When trace 408 is at a lower level near the horizontal axis, the electrical isolation switch is open (preventing current from flowing through the isolation switch). Trace 408 represents the state of the electrical isolation switch. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0061] Figure 4The fifth graph is a graph of BISG state versus time. The vertical axis represents BISG state, and when trace 410 is at a lower level near the horizontal axis, the BISG is closed. When trace 410 is at a higher level near the vertical axis arrow, the BISG is providing positive torque to the drivetrain. When trace 410 is near an intermediate level, the BISG is providing negative or holding torque. Trace 410 represents the BISG state. The horizontal axis represents time, and time increases from the left side of the graph to the right side.

[0062] Figure 4 The sixth graph is a graph of the transmission disconnect clutch transfer function adaptation request state versus time. The vertical axis represents the transmission disconnect clutch transfer function adaptation request, and when the trace 412 is close to the vertical axis arrow, the transmission disconnect clutch transfer function adaptation request is in effect. When the trace 412 is close to the horizontal axis arrow, the transmission disconnect clutch transfer function adaptation request is not in effect. The trace 412 represents the transmission disconnect clutch transfer function adaptation request state. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0063] Figure 4 The seventh graph is a graph of the transmission disconnect clutch transfer function adaptation state versus time. The vertical axis represents the transmission disconnect clutch transfer function adaptation state, and the transmission disconnect clutch transfer function adaptation state indicates that when trace 414 is close to the vertical axis arrow, the transmission disconnect clutch transfer function is being adapted. When trace 414 is close to the horizontal axis, transmission disconnect clutch transfer function adaptation has not occurred. Trace 414 represents the transmission disconnect clutch transfer function adaptation request state. The horizontal axis represents time and time increases from the left side of the graph to the right side of the graph.

[0064] Figure 4 An example transmission disconnect clutch transfer function adaptation sequence is shown in which the engine is stopped and then repositioned to increase the torque required to rotate the engine and the engine's fuel pump so that a larger torque range of the transmission disconnect clutch transfer function can be adapted (e.g., adapted to improve accuracy).

[0065] At time t0, the engine is operating (e.g., burning air and fuel) and the torque required to rotate the engine is zero because the engine is operating under its own power. The torque required to rotate the fuel pump is also zero because the engine is rotating under its own power. The electrical isolation switch is closed to allow current to flow through the electrical isolation switch. The BISG is not activated and the transmission disconnect clutch transfer function adaptation request is not valid. The transmission disconnect clutch adaptation status indicates that the transmission disconnect clutch transfer function has not been adapted.

[0066] Between time t0 and time t1, the engine stops rotating and comes to a stop. The electrical isolation switch remains closed and the BISG is not activated. The transmission disconnect clutch transfer function adaptation request is not valid and the transmission disconnect clutch transfer function is not adapted.

[0067] At time t1, a transmission disconnect clutch transfer function adaption request is asserted. The transmission disconnect clutch transfer function adaption request may be asserted in response to the distance driven by the vehicle, the presence of a transmission torque disturbance, or a manual request to adapt the transmission disconnect clutch transfer function. The engine remains stopped (e.g., not rotating) and the engine rotation required torque and the fuel pump rotation required torque are determined to be non-zero in response to the engine stop position.

[0068] At time t2, the electrical disconnect switch is opened, the BISG is activated, and the transmission disconnect clutch transfer function adaptation request remains in effect. Opening the electrical disconnect switch reduces the likelihood of voltage variations on the low-voltage DC bus 262. The engine remains stopped (e.g., not rotating) and the engine rotation torque and fuel pump rotation torque remain at their previous respective values. The ISG also begins rotating one side of the transmission disconnect clutch (not shown).

[0069] Between time t2 and time t3, the BISG rotates the engine and the torque required to rotate the engine and the torque required to rotate the engine fuel pump vary with engine position. The engine is not burning air and fuel, and the electrical disconnect switch remains open. The transmission disconnect clutch transfer function adaptation request remains active and the transmission disconnect clutch transfer function is not adapted.

[0070] At time t3, the BISG stops spinning the engine and the torque required to spin the engine and the torque required to spin the fuel pump are at a higher level, requiring more torque to begin spinning the engine. When the torque applied to the engine via the BISG is removed, the engine stops spinning in a position where it does not spin forward or backward. The BISG also begins to provide holding torque (e.g., negative torque that resists movement of the engine crankshaft) to the driveline and engine crankshaft. The driveline disconnect clutch transfer function adaptation begins shortly after time t3, as shown by trace 414 transitioning to a higher level.

[0071] Between time t3 and time t4, the applied pressure to the driveline disconnect clutch increases, causing the torque transmitted through the driveline disconnect clutch to increase. However, because the engine is in a position where the torque required to rotate is high, the engine does not rotate. The controller determines the torque transmitted through the driveline disconnect clutch and the applied force applied to the driveline disconnect clutch. Values ​​within the driveline disconnect clutch transfer function can be adjusted in response to the applied force and the torque transmitted through the driveline disconnect clutch.

[0072] At time t4, the transmission disconnect clutch adaptation request is withdrawn and transmission disconnect clutch adaptation is stopped. The BISG is deactivated and the electrical disconnect switch is closed so that power can be exchanged from the low-voltage battery. The engine remains deactivated and the torque required for engine and fuel pump rotation remains at its previous value. The ISG stops rotating (not shown).

[0073] In this way, as the ISG rotates the other side of the driveline disconnect clutch, the driveline disconnect clutch transfer function can be adjusted while the engine provides torque to ground the driveline disconnect clutch (e.g., prevent it from moving). As the force applied to the driveline disconnect clutch increases, the values ​​included in the driveline disconnect clutch transfer function can be adjusted.

[0074] Now refer to Figure 5 , a transmission disconnect clutch transfer function 500 is shown. Alternatively, the transfer function 500 can be described as a force versus clutch torque capacity relationship. Curve 502 can be determined by a plurality of data points (such as 512) that are a function of the transmission disconnect clutch apply pressure and the transmission disconnect clutch torque capacity (e.g., the amount of torque that the transmission disconnect clutch can transfer). The transmission disconnect clutch transfer function 500 can be adjusted by increasing the clutch apply pressure while monitoring the transmission disconnect clutch torque capacity. The transmission disconnect clutch torque capacity can be determined based on the ISG current. For example, the ISG current used to rotate one side of the transmission input shaft and the transmission disconnect clutch can be determined by the ISG current when the transmission disconnect clutch is fully disengaged and when the ISG is operating in a speed control mode (e.g., the ISG torque can be varied to operate the ISG at a desired speed). The transmission disconnect clutch can then be slowly closed such that the transmission disconnect clutch torque capacity increases. The ISG speed follows the desired ISG speed (which can be a constant speed), and the ISG current increases as the transmission disconnect clutch torque capacity increases. The ISG current can then be converted to torque. Specifically, the torque supplied to the ISG to rotate the driveline with the driveline disconnect clutch disengaged is subtracted from the driveline rotational torque when the driveline disconnect clutch application pressure is increased to determine the driveline disconnect clutch torque capacity for a given driveline disconnect clutch application pressure. For example, the driveline disconnect clutch application pressure at 532 corresponds to the driveline disconnect clutch torque capacity 522. Data point 530 represents the intersection of the driveline disconnect clutch application pressure 532 and the driveline disconnect clutch torque capacity 522. Curve 512 can be based on multiple points similar to 530.

[0075] The transmission disconnect clutch transfer function 500 can be utilized as follows: if it is desired that the transmission disconnect clutch transfer 200 Newton meters (Nm) of torque, the transmission disconnect clutch transfer function 500 can be referenced by a torque capacity of 200 Nm (e.g., a vertical axis variable) to find a corresponding transmission disconnect clutch apply pressure (e.g., a horizontal axis variable) that provides a transmission disconnect clutch torque capacity of 200 Nm. The transmission disconnect clutch apply pressure can then be applied to the transmission disconnect clutch so that the transmission disconnect clutch can transfer up to 200 Nm.

[0076] Now refer to Figure 6 , a flow chart for operating a hybrid vehicle is shown. Figure 6 At least some parts of the method may be stored as Figures 1 to 3A The executable instructions in the non-transitory memory of the system shown in are incorporated. In addition, Figure 6 Certain portions of the methods may occur in the physical world as operations or actions performed by a controller to transform the operating state of one or more devices. Some of the control parameters described herein may be determined by receiving input from the sensors and actuators described previously. Figure 6 The method can also provide Figure 5 The operating sequence shown, and the transmission system can operate under the conditions described herein via instructions stored in the controller memory.

[0077] At 602, method 600 determines vehicle operating conditions. Vehicle operating conditions may include, but are not limited to, engine speed, engine position, fuel pump position, transmission disconnect clutch apply pressure, transmission disconnect clutch torque transfer capacity, ISG speed and torque, DC / DC disconnect switch status, BISG operating status, and engine operating status. Method 600 may determine operating conditions from various sensors described herein.

[0078] At 604, method 600 determines whether to request a transmission disconnect clutch transfer function adaptation. Method 600 or another routine may request a transmission disconnect clutch transfer function adaptation. In one example, the transmission disconnect clutch may be adapted based on the distance traveled by the vehicle, the time since the transmission disconnect clutch transfer function was last adapted, the transmission torque disturbance level, or other conditions. For example, if the vehicle has traveled 10,000 kilometers without the transmission disconnect clutch being adapted, method 600 may request a transmission disconnect clutch transfer function adaptation. Alternatively, method 600 may request a transmission disconnect clutch transfer function adaptation after every 100 hours of vehicle operation. If method 600 determines that a transmission disconnect clutch transfer function adaptation is requested, the answer is yes and method 600 proceeds to 606. Otherwise, the answer is no and method 600 proceeds to 640. Method 600 may also require that the vehicle's transmission be engaged in neutral or park before method 600 proceeds to 606.

[0079] At 640, method 600 engages and disengages the powertrain disconnect clutch in response to an existing powertrain disconnect clutch transfer function in the controller memory. The powertrain disconnect clutch transfer function may be input to the controller during vehicle manufacturing, or the powertrain disconnect clutch transfer function may include an adapted or adjusted value based on vehicle operating conditions. Method 600 then exits.

[0080] At 606, method 600 stops engine rotation. Engine rotation can be stopped by stopping the flow of fuel to the engine cylinders. In addition, the spark supplied to the engine cylinders can be stopped. Engine rotation is stopped so that the engine can ground one side of the transmission disconnect clutch to facilitate transmission disconnect clutch transfer function adaptation. By grounding one side of the transmission disconnect clutch, it can be ensured that all torque transmitted through the transmission disconnect clutch is reflected in the transmission disconnect clutch torque capacity. The transmission disconnect clutch is also fully disengaged. After stopping engine rotation, method 600 proceeds to 608.

[0081] At 608, method 600 determines engine position and fuel pump position. The engine position and fuel pump position may be determined by the engine crankshaft position and the engine camshaft position. In one example, the crankshaft indicates a new crankshaft position via gear teeth every 10 crankshaft degrees. For each engine revolution, the camshaft position may be indicated via multiple gear teeth. The engine and fuel pump positions at which the engine and fuel pump require the most torque or greater torque than at other engine positions may be stored in controller memory. Method 600 proceeds to 610.

[0082] At 610, method 600 adjusts the operation of relief valve 312, which regulates the amount of fuel entering mechanically driven fuel pump 91. In one example, relief valve 312 is commanded to open to provide a maximum amount of fuel to enter fuel pump 91. For example, if fuel pump 91 has a capacity to pump between 1 and 4 cubic centimeters of fuel, relief valve 312 is operated to allow 4 cubic centimeters of fuel to enter fuel pump 91. Relief valve 312 can be commanded to open and / or close as engine 10 rotates. By increasing the amount of fuel entering fuel pump 91, the torque required to rotate fuel pump 91 can be increased. Additionally, increasing the torque required to rotate fuel pump 91 can increase the range of transmission disconnect clutch torque capacity, which can be the basis for adjusting the transmission disconnect clutch transfer function. For example, if the torque required to rotate fuel pump 91 can be increased by 5 Nm, then the transmission disconnect clutch transfer function can be adapted to a torque capacity of up to 55 Nm instead of a torque capacity of 50 Nm. Method 600 proceeds to 612 after adjusting the fuel pump relief valve to increase the torque required to rotate the engine fuel pump.

[0083] At 612, method 600 rotates the engine and fuel pump via the BISG when the transmission disconnect clutch is fully disengaged. The engine and fuel pump can be rotated to positions stored in the controller memory. The engine can be rotated forward or backward to reach a predetermined engine position. The predetermined engine position can be an engine position where the torque applied to rotate the engine and fuel pump exceeds a threshold torque and where the engine does not rotate after the torque applied to the engine via the BISG is released after the engine rotates. The engine position can be an engine position where the engine compression torque (e.g., the torque that causes the engine to rotate against the pressure in the cylinder) is maximum and the engine movement exceeds a predetermined actual total crankshaft degree once torque is no longer applied to the engine. Once the engine reaches the predetermined position, rotation of the engine stops and the BISG does not apply torque to rotate the engine. Method 600 proceeds to 614.

[0084] At 614, method 600 adjusts the position of the front end accessory drive (FEAD) pretensioner 267, opens the electrical isolation switch 260, and applies a holding torque to the engine 10 via the BISG 266. In one example, the FEAD pretensioner 267 is activated, the electrical isolation switch 260 is opened, and the BISG is commanded to provide a negative (e.g., maximum) holding torque to prevent the engine from rotating. The FEAD pretensioner can be activated to reduce belt slip between the BISG 266 and the engine 10 so that the engine position can be maintained during the transmission disconnect clutch transfer function adaptation. Additionally, opening the electrical isolation switch 260 can reduce voltage disturbances to other vehicle electrical systems while the transmission disconnect clutch transfer function is being adjusted. Increasing the BISG holding torque can allow greater application pressure to be applied to the transmission disconnect clutch before the engine rotates and the transmission disconnect clutch transfer function adaptation stops. Method 600 proceeds to 616.

[0085] At 616, method 600 operates the ISG 240 in a speed control mode at a constant speed (e.g., in speed control mode, ISG torque varies and the ISG speed is maintained at or follows a desired ISG speed). By operating the ISG in speed control mode, an accurate estimate of the driveline disconnect clutch torque capacity can be determined. One or more transmission clutches can also be disengaged so that the ISG 240 does not spin the wheels. Method 600 also determines the torque required to rotate the ISG at a constant speed. In one example, the ISG current is used to reference a table or function of output ISG torque as a function of ISG current. Method 600 proceeds to 618.

[0086] At 618, method 600 incrementally increases the applied pressure applied to close the transmission disconnect clutch. Each time the applied pressure applied to the disconnect clutch is increased, the transmission disconnect clutch torque capacity is determined from the ISG torque. Specifically, the current supplied to the ISG 240 is determined via sensing the current supplied to the ISG 240. The ISG torque is then determined from the ISG current via a function that relates the ISG current to the ISG torque. The ISG torque supplied when the transmission disconnect clutch is fully disengaged is subtracted from the ISG torque at the transmission disconnect clutch applied pressure or force of the present invention to determine the transmission disconnect clutch torque capacity for the transmission disconnect clutch applied pressure or force of the present invention. The transmission disconnect clutch applied pressure or force may be increased until the engine begins to rotate. When the engine begins to rotate, the transmission disconnect clutch transfer function adaptation may cease. After adjusting the transmission disconnect clutch applied pressure to a plurality of different applied pressures, the method proceeds to 620.

[0087] At 620, method 600 can adjust the values ​​in the transmission disconnect clutch transfer function. Specifically, if the transmission torque capacity of a particular transmission disconnect clutch force, as determined at 618, varies by more than a threshold amount (e.g., 10%) relative to the corresponding torque capacity of the same transmission disconnect clutch force stored in the controller memory, then the value of the transmission disconnect clutch transfer function stored in the controller memory is adjusted to the value determined at 618. One or more values ​​of the transmission disconnect clutch transfer function stored in the controller memory can be adjusted in this manner. Method 600 proceeds to 622.

[0088] At 622, method 600 determines whether one or more of the following conditions are met. Method 600 determines whether a timer (which estimates the pressure decay within the engine cylinders) has expired or the engine has not rotated for more than a threshold amount of time since the most recent time the engine stopped rotating. Method 600 also determines whether the BISG temperature is greater than a threshold. Additionally, method 600 may determine whether adaptation of the transmission disconnect clutch transfer function is complete. If the answer to any of the above conditions is yes, method 600 proceeds to 624. Otherwise, method 600 returns to 618.

[0089] At 624 , method 600 stops adapting the driveline disconnect clutch transfer function. Method 600 also disengages the driveline disconnect clutch, stops rotating the ISG 240 , deactivates the BISG 266 , and deactivates the FEAD pretensioner 267 . Method 600 then exits.

[0090] In this way, method 600 can adapt the transmission disconnect clutch transfer function and adjust the transmission actuator to improve transmission disconnect clutch adaptation.In addition, the transmission disconnect clutch transfer function can be adapted to obtain a higher transmission disconnect clutch application pressure.

[0091] Thus, method 700 provides a vehicle operating method comprising: requesting an adjustment to a force-to-clutch torque capacity relationship; adjusting an engine stopping position in response to the request; and adjusting the force-to-clutch torque capacity relationship. The method includes storing the force-to-clutch torque capacity relationship in a controller memory. The method includes adjusting the engine stopping position including adjusting the engine to a position based on engine compression torque. The method includes the engine position based on engine compression torque being an engine position where the engine rotates less than a predetermined total crankshaft degree after the engine is stopped at the engine position and torque applied to the engine via the electric motor is released. The method also includes, before adjusting the force-to-clutch torque capacity relationship, operating the electric motor in a speed control mode and incrementally closing a driveline disconnect clutch in response to the request. The method also includes not operating the electric motor in a speed control mode and incrementally closing the driveline disconnect clutch unless a transmission coupled to the electric motor is in park or neutral. The method also includes not adjusting the force-to-clutch torque capacity relationship in response to engine motion.

[0092] The method also provides a vehicle operating method, the vehicle operating method including: requesting an adjustment of the force to clutch torque capacity relationship; adjusting a fuel pump overflow control valve in response to the request; and adjusting the force to clutch torque capacity relationship. The method includes the force to clutch torque capacity relationship describing the operation of a transmission disconnect clutch positioned between the engine and the motor in the transmission. The method also includes adjusting the position of the engine to a predetermined engine position at which the torque required to rotate the fuel pump is greater than a threshold torque. The method also includes disconnecting a low-voltage disconnect switch in response to the request. The method also includes activating a front-end accessory drive pretensioner in response to the request. The method also includes rotating the engine via a belt starter generator in response to the request, stopping the engine at a predetermined position, and then applying a holding torque to the transmission via the belt starter generator. The method includes the predetermined position being based on the position of the fuel pump.

[0093] It should be noted that the example control and estimation routines included herein can be used with a variety of engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-volatile memory and executed by a control system including a controller in conjunction with various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc. Thus, the various actions, operations, and / or functions shown may be performed in the order shown, in parallel, or omitted in some cases. Similarly, the processing order is not necessarily required to achieve the features and advantages of the example embodiments described herein but is provided for ease of illustration and description. One or more of the actions, operations, and / or functions shown may be repeated depending on the specific strategy used. Furthermore, at least a portion of the described actions, operations, and / or functions may graphically represent code to be programmed into the non-volatile memory of a computer-readable storage medium in the control system. When the described actions are implemented by executing instructions in a system including various engine hardware components and one or more controllers, the control actions may also transform the operating states of one or more sensors or actuators in the physical world.

[0094] The following is a summary of this specification. After reading this specification, those skilled in the art will recognize numerous variations and modifications without departing from the spirit and scope of this specification. For example, I3, I4, I5, V6, V8, V10, and V12 engines operating in natural gas, gasoline, diesel, or alternative fuel configurations may benefit from this specification.

[0095] According to the present invention, a vehicle operating method includes: requesting an adjustment of an effort and clutch torque capacity relationship; adjusting a stopping position of an engine in response to the request; and adjusting the effort and clutch torque capacity relationship.

[0096] According to one embodiment, the effort versus clutch torque capacity relationship is stored in controller memory.

[0097] According to one embodiment, adjusting the stopping position of the engine includes adjusting the engine to a position based on a compression torque of the engine.

[0098] According to one embodiment, the engine position based on the engine compression torque is an engine position where the engine rotates less than a predetermined actual total crankshaft degrees after the engine is parked at the engine position and torque applied to the engine via the electric machine is released.

[0099] According to one embodiment, the above invention is further characterized by operating the electric machine in a speed control mode and incrementally closing the transmission disconnect clutch before adjusting the relationship between the effort and the clutch torque capacity.

[0100] According to one embodiment, the above invention is further characterized by not operating the electric machine in the speed control mode and incrementally closing the driveline disconnect clutch unless the transmission coupled to the electric machine is in park or neutral.

[0101] According to one embodiment, the above invention is further characterized by not adjusting the effort versus clutch torque capacity relationship in response to engine motion.

[0102] According to the present invention, a vehicle operating method includes: requesting an adjustment of an effort to clutch torque capacity relationship; adjusting a fuel pump spill control valve in response to the request; and adjusting the effort to clutch torque capacity relationship.

[0103] According to one embodiment, the force to clutch torque capacity relationship describes the operation of a transmission disconnect clutch positioned in a transmission between the engine and the electric machine.

[0104] According to one embodiment, the above invention is further characterized by adjusting the position of the engine to a predetermined engine position where the torque required to rotate the fuel pump is greater than a threshold torque.

[0105] According to one embodiment, the above invention is further characterized by opening the low voltage disconnect switch in response to the request.

[0106] According to one embodiment, the above invention is further characterized by activating a front end accessory drive pretensioner in response to the request.

[0107] According to one embodiment, the above invention is further characterized by rotating the engine via a belt starter generator in response to the request, stopping the engine at a predetermined position, and then applying a holding torque to the driveline via the belt starter generator.

[0108] According to one embodiment, the predetermined position is based on a position of a fuel pump.

[0109] According to the present invention, a vehicle system is provided, comprising: a motor; an engine including a mechanically driven fuel pump; a transmission disconnect clutch mechanically coupled to the engine and the motor; a belt-driven starter generator mechanically coupled to the engine; and a controller including executable instructions stored in a non-volatile memory, the executable instructions causing the controller to adjust the engine to a stopped position based on the position of the fuel pump in response to a request to adjust the relationship between the force of the transmission disconnect clutch and the torque capacity of the clutch.

[0110] According to one embodiment, the above invention is further characterized by an instruction to operate the electric motor in a speed control mode in response to the request.

[0111] According to one embodiment, the controller generates the request.

[0112] According to one embodiment, the above invention is further characterized by additional instructions for incrementally increasing the application force of the powertrain disconnect clutch in response to the request.

[0113] According to one embodiment, the above invention is also characterized by an additional command to bring the engine to a stop position via the belt-driven starter generator.

[0114] According to one embodiment, the above invention is further characterized by the additional instruction to adjust the position of the fuel pump relief valve in response to the request.

Claims

1. A vehicle operating method, comprising: Using a controller to request adjustment of the relationship between the force applied to the powertrain disengagement clutch and the clutch torque capacity; adjusting the engine to a stopped position based on a position of a fuel pump in response to the request using the controller; and The controller is used to adjust the relationship between the effort and clutch torque capacity.

2. The method of claim 1 wherein the effort versus clutch torque capacity relationship is stored in controller memory. 3 . The method of claim 1 , wherein adjusting the stopping position of the engine comprises adjusting the engine to a position based on engine compression torque.

4. The method of claim 3 , wherein the engine position based on the engine compression torque is an engine position where the engine rotates less than a predetermined actual total crankshaft degrees after the engine is parked at the engine position and torque applied to the engine via an electric machine is released.

5. The method of claim 1 further comprising, in response to the request, operating the electric machine in a speed control mode and incrementally closing a transmission disconnect clutch before adjusting the force to clutch torque capacity relationship.

6. The method of claim 5 further comprising not operating the electric machine in the speed control mode and incrementally closing the driveline disconnect clutch unless a transmission coupled to the electric machine is in park or neutral.

7. The method of claim 5 further comprising not adjusting said effort to clutch torque capacity relationship in response to said engine motion.

8. The method of claim 1, further comprising: A fuel pump spill control valve is adjusted in response to the request.

9. The method of claim 8, further comprising opening a low voltage disconnect switch in response to the request.

10. A vehicle system comprising: Motor; an engine including a mechanically driven fuel pump; a driveline disconnect clutch mechanically coupled to the engine and the electric machine; a belt-driven starter-generator coupled to the engine; and A controller comprising executable instructions stored in a non-volatile memory, the executable instructions causing the controller to adjust the engine to a stopped position based on the position of the fuel pump in response to a request to adjust the relationship between the force of the transmission disengagement clutch and the clutch torque capacity.

11. The system of claim 10, further comprising instructions for operating the electric motor in a speed control mode in response to the request.

12. The system of claim 10, wherein the controller generates the request.

13. The system of claim 10 further comprising additional instructions for incrementally increasing the application force of the driveline disconnect clutch in response to the request.

14. The system of claim 10 further comprising additional instructions for adjusting the engine to the stopped position via the belt driven starter generator.

15. The system of claim 10 further comprising additional instructions for adjusting a position of a fuel pump relief valve in response to the request.

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