Abstract: A method of controlling a vehicle may include determining a proximity to a stuck condition based on measured vehicle motion parameters and a wheel speed measured by a wheel speed sensor associated with one or more wheels of the vehicle. The method may further include generating a notification to a driver of the vehicle in response to the proximity to the stuck condition indicating that the vehicle is either in a stuck condition or a nearly stuck condition, and responsive to driver selection of an unstuck mode, executing an unstuck algorithm to automatically control operation of the vehicle to achieve a free condition.

Abstract: A method of controlling a vehicle may include determining a proximity to a stuck condition based on measured vehicle motion parameters and a wheel speed measured by a wheel speed sensor associated with one or more wheels of the vehicle. The method may further include generating a notification to a driver of the vehicle in response to the proximity to the stuck condition indicating that the vehicle is either in a stuck condition or a nearly stuck condition, and responsive to driver selection of an unstuck mode, executing an unstuck algorithm to automatically control operation of the vehicle to achieve a free condition.

Abstract: A vehicle includes a transmission and a controller. The transmission has clutches that are configured to establish multiple speed ratios, including a first clutch. The first clutch has a measured drag torque distribution. The measured drag torque distribution has a median and a standard deviation. The controller is programmed to increase a pressure at a rate to engage the first clutch and to increase the rate in response to a measured first clutch torque exceeding the median by a predetermined multiple of the standard deviation.

Abstract: During a transmission upshift, a torque capacity of an off-going clutch is maintained at a non-zero state during the transition from the torque phase to the inertia phase and throughout a substantial portion of the inertia phase. This permits the inertia phase to be completed faster without an unacceptable increase in output torque during the torque phase. Monotonically reducing the off-going clutch torque and using feedback from an output torque sensor enable sufficiently precise control of the off-going clutch torque capacity during this interval.

Abstract: A vehicle includes a transmission and a controller. The transmission has clutches that are configured to establish multiple speed ratios, including a first clutch. The first clutch has a measured drag torque distribution. The measured drag torque distribution has a median and a standard deviation. The controller is programmed to increase a pressure at a rate to engage the first clutch and to increase the rate in response to a measured first clutch torque exceeding the median by a predetermined multiple of the standard deviation.

Abstract: During a transmission upshift, a torque capacity of an off-going clutch is maintained at a non-zero state during the transition from the torque phase to the inertia phase and throughout a substantial portion of the inertia phase. This permits the inertia phase to be completed faster without an unacceptable increase in output torque during the torque phase. Monotonically reducing the off-going clutch torque and using feedback from an output torque sensor enable sufficiently precise control of the off-going clutch torque capacity during this interval.

Abstract: A method of determining automatic transmission lubrication fluid flow rates corresponding to a running vehicle without direct oil flow measurements is disclosed. A set of in-vehicle clutch torques for a chosen clutch pack during a gear shift event for a set of shift conditions is obtained. A series of bench tests at various clutch-pack clearances and oil-flow rates for the set of shift conditions are performed. The clearances and oil-flow rates are adjusted in response to the measured magnitudes exceeding thresholds. In-vehicle transmission lubrication oil-flow rates are estimated at the chosen clutch pack for the set of shift conditions when the bench-test and in-vehicle clutch torques are less than the thresholds. The steps are reproduced for other engine conditions and fluid temperatures corresponding to other transmission gear positions. A functional map of in-vehicle oil flow rates are produced, and the transmission is adjusted based on the map.

Abstract: A method of operating a vehicle includes measuring a transmission output torque, measuring impeller and turbine speeds, estimating a transmission component torque, and adjusting an engine torque to avoid overstressing a transmission component such as a gear. The method does not rely on an accurate estimate of engine torque. Furthermore, the method does not rely on a fixed transmission torque rating in each gear ratio.

Abstract: A method of determining automatic transmission lubrication fluid flow rates corresponding to a running vehicle without direct oil flow measurements is disclosed. A set of in-vehicle clutch torques for a chosen clutch pack during a gear shift event for a set of shift conditions is obtained. A series of bench tests at various clutch-pack clearances and oil-flow rates for the set of shift conditions are performed. The clearances and oil-flow rates are adjusted in response to the measured magnitudes exceeding thresholds. In-vehicle transmission lubrication oil-flow rates are estimated at the chosen clutch pack for the set of shift conditions when the bench-test and in-vehicle clutch torques are less than the thresholds. The steps are reproduced for other engine conditions and fluid temperatures corresponding to other transmission gear positions. A functional map of in-vehicle oil flow rates are produced, and the transmission is adjusted based on the map.

Abstract: A method of operating a transmission includes measuring an output torque, estimating a gearbox input torque using a model, and estimating gearbox component torques based on a detailed gearbox model. The model used to estimate the input torque varies depending on whether a torque converter is locked, open, or slipping. In some operating conditions, multiple estimates are available for gearbox input torque, impeller torque, or shift element torque in which case the models are adapted. When an estimated component torque is outside an expected range, a warning flag is raised and diagnostic data is saved. When an estimated torque approaches or exceeds a torque limit, the input torque command may be reduced to prevent component damage. A warning flag may also be raised and diagnostic data saved in response to a model parameter being adapted to a value outside of a predetermined range.

Abstract: A method of operating a transmission includes measuring an output torque, estimating a gearbox input torque using a model, and estimating gearbox component torques based on a detailed gearbox model. The model used to estimate the input torque varies depending on whether a torque converter is locked, open, or slipping. In some operating conditions, multiple estimates are available for gearbox input torque, impeller torque, or shift element torque in which case the models are adapted. When an estimated component torque is outside an expected range, a warning flag is raised and diagnostic data is saved. When an estimated torque approaches or exceeds a torque limit, the input torque command may be reduced to prevent component damage. A warning flag may also be raised and diagnostic data saved in response to a model parameter being adapted to a value outside of a predetermined range.

Abstract: A method of operating a vehicle includes measuring a transmission output torque, measuring impeller and turbine speeds, estimating a transmission component torque, and adjusting an engine torque to avoid overstressing a transmission component such as a gear. The method does not rely on an accurate estimate of engine torque. Furthermore, the method does not rely on a fixed transmission torque rating in each gear ratio.