Abstract: A method of downshifting an automotive transmission. An on-coming transmission element is stroked while pressure for an off-going element is reduced. Pressure for the stroked on-coming element is increased to be sufficient to carry torque. Pressure for the off-going element is reduced below a torque transmitting amount once the stroked on-coming element has a sufficient torque carrying capacity. Torque capacities for the elements are determined from transmission output torque and acceleration and transmission input torque and acceleration. Feed forward or feedback terms for off-going and on-coming element torque capacities may be calculated using the transmission output torque, transmission input acceleration, and transmission input torque.

Abstract: A bench test calibration method for generating wet clutch torque transfer functions includes obtaining in-vehicle clutch torques at a set of shift conditions; performing a series of bench tests at various clutch pack clearances and lubrication oil flow rates at the set of shift conditions; adjusting clutch pack clearances and lubrication oil flow rates during the series of bench tests in response to a difference between a bench test measured clutch torques and the corresponding in-vehicle clutch torques exceeding a threshold; and recording relationships between first bench test measured torques and force profiles of a clutch actuator relative to the adjusted clutch pack clearances and lubrication oil flow rates for each of the set of shift conditions as a first transfer function.

Abstract: A vehicle powertrain includes a transmission and a clutch. The slip of the clutch is adjusted to a predefined target where a sensed parameter of a shaft of the transmission corresponds to a specified noise, vibration, and harshness (NVH) level in the powertrain. The sensed parameter of the transmission shaft may be one of acceleration, speed, and torque of the transmission shaft. The transmission shaft may be one of the input shaft and output shaft of the transmission.

Abstract: A transmission and control method are disclosed which ensure proper stroke pressure and minimize torque transients during a shift event. The transmission includes a clutch having a torque capacity based on a fluid pressure, a torque sensor adapted to measure a torque value that varies in relationship to the torque capacity, and a controller. The method includes varying the fluid pressure around a predetermined value, measuring a resulting torque difference with the torque sensor, and adjusting a clutch control parameter if the resulting torque difference is less than a threshold value.

Abstract: Designs to package a magneto-elastic torque sensor in an automotive transmission for volume production applications are provided. A transfer case assembly includes a transfer case shaft having a magnetized region and a magnetic torque sensor, for detecting torque of the transfer case shaft, mounted on at least one bushing supporting the transfer case shaft. A drive axle assembly includes an axle housing, an input shaft having a magnetized region, and a magnetic torque sensor, for detecting torque of the input shaft, mounted to the axle housing.

Abstract: A control system and method for controlling a multiple gear ratio automatic transmission in a powertrain for an automatic transmission having pressure activated friction torque elements to effect gear ratio upshifts. The friction torque elements are synchronously engaged and released during a torque phase of an upshift event as torque from a torque source is increased while allowing the off-going friction elements to slip, followed by an inertia phase during which torque from a torque source is modulated. A perceptible transmission output torque reduction during an upshift is avoided. Measured torque values are used during a torque phase of the upshift to correct an estimated oncoming friction element target torque so that transient torque disturbances at an oncoming clutch are avoided and torque transients at the output shaft are reduced.

Abstract: Designs to package a magneto-elastic torque sensor in an automotive transmission for volume production applications are provided. One transmission includes an output shaft and a magnetic torque sensor. The output shaft has a magnetized region. The sensor, for detecting torque of the output shaft, is mounted on friction reduction members such as bushings supporting the output shaft. In another transmission, the sensor is alternatively mounted to a transmission case.

Abstract: A calibration method includes obtaining in-vehicle measured clutch torques at a set of shift conditions; performing a series of bench tests at various clutch pack clearances and lubrication oil flow rates at the set of shift conditions; adjusting clutch pack clearances and lubrication oil flow rates during the series of bench tests in response to a difference between a bench test measured clutch torques and the corresponding in-vehicle measured clutch torques exceeding a threshold; and recording relationships between first bench test measured torques and force profiles of a clutch actuator relative to the adjusted clutch pack clearances and lubrication oil flow rates for each of the set of shift conditions as a first transfer function in response to the difference between the first bench test measured clutch torques and the in-vehicle clutch torques not exceeding the threshold for each of the set of shift conditions.

Abstract: A control system and method for controlling a multiple gear ratio automatic transmission in a powertrain for an automatic transmission having pressure activated friction torque elements to effect gear ratio upshifts. The friction torque elements are synchronously engaged and released during a torque phase of an upshift event as torque from a torque source is increased while allowing the off-going friction elements to slip, followed by an inertia phase during which torque from a torque source is modulated. A perceptible transmission output torque reduction during an upshift is avoided. Measured torque values are used during a torque phase of the upshift to correct an estimated oncoming friction element target torque so that transient torque disturbances at an oncoming clutch are avoided and torque transients at the output shaft are reduced.

Abstract: A multiple ratio transmission having an input shaft, an output shaft and oncoming clutch and off-going clutch for effecting ratio upshifts is provided. The transmission also includes a transmission controller configured for controlling shifts. During the torque phase of a ratio upshift, the controller increases input torque. Next, the controller estimates an oncoming clutch target torque. The controller controls a torque input to ensure the off-going clutch remains locked. The controller measures an actual transmission value for a torque transmitting element of the transmission and corrects the oncoming clutch target torque using the actual transmission value whereby an increasing torque for the oncoming friction element is achieved with minimal torque transients along the output shaft during the upshift.

Abstract: A method of downshifting an automotive transmission. An on-coming transmission element is stroked while pressure for an off-going element is reduced. Pressure for the stroked on-coming element is increased to be sufficient to carry torque. Pressure for the off-going element is reduced below a torque transmitting amount once the stroked on-coming element has a sufficient torque carrying capacity. Torque capacities for the elements are determined from transmission output torque and acceleration and transmission input torque and acceleration. Feed forward or feedback terms for off-going and on-coming element torque capacities may be calculated using the transmission output torque, transmission input acceleration, and transmission input torque.

Abstract: A multiple ratio transmission having an input shaft, an output shaft and oncoming clutch and off-going clutch for effecting ratio upshifts is provided. The transmission also includes a transmission controller configured for controlling shifts. During the torque phase of a ratio upshift, the controller increases input torque. Next, the controller estimates an oncoming clutch target torque. The controller controls a torque input to ensure the off-going clutch remains locked. The controller measures an actual transmission value for a torque transmitting element of the transmission and corrects the oncoming clutch target torque using the actual transmission value whereby an increasing torque for the oncoming friction element is achieved with minimal torque transients along the output shaft during the upshift.

Abstract: A hydraulically actuated clutch is controlled based on a mathematical model that predicts the position of the clutch piston based on the profile of the commanded pressure over time. During a clutch engagement, a set of delays associated with the preparatory phase of engagement are measured and compared to predicted values. Model parameters are then adaptively adjusted based on the differences between the measured and predicted delays and on an estimate of the sensitivities between model parameters and the delays. Subsequent engagements are controlled based on the updated mathematical model to reduce the delays. Changes in the measured delays following adaptation of the model parameters are utilized to update the estimate of the sensitivities.

Abstract: A hydraulically actuated clutch is controlled based on a mathematical model that predicts the position of the clutch piston based on the profile of the commanded pressure over time. During a clutch engagement, a set of delays associated with the preparatory phase of engagement are measured and compared to predicted values. Model parameters are then adaptively adjusted based on the differences between the measured and predicted delays and on an estimate of the sensitivities between model parameters and the delays. Subsequent engagements are controlled based on the updated mathematical model to reduce the delays. Changes in the measured delays following adaptation of the model parameters are utilized to update the estimate of the sensitivities.

Abstract: A method for enacting DFSO in a motor vehicle having an engine and a transmission. The method includes, during a condition of normal engine-braking efficiency, disabling the DFSO below a higher gear of the transmission. During a condition of reduced engine-braking efficiency, by contrast, the DFSO is disabled below a lower gear of the transmission.

Abstract: When a transmission controller issues a control command, such as pressure to control clutch torque, the response may be delayed due to dynamic properties of the control system. These properties can be modeled using a dynamic response model. One potential model is a combination of a pure time delay and a first order distributed delay. Control methods may be improved in several ways by accounting for the dynamic response. First, the dynamic response model may be used to improve adaptation of a transfer function between the commanded control signal and the clutch torque. Second, the command may be adjusted based on the dynamic response model. Both the pure time delay and the time constant of the first order distributed delay may be functions of operating conditions such as temperature.

Abstract: The following description relates to systems and methods for adjusting vehicle response parameters in response to indications of vehicle operator preferences. In one example approach, a method comprises, during a cruise control mode of operation, adjusting a vehicle response parameter from a default set-point based on an indication of vehicle operator preference.

Abstract: A system and method for controlling a vehicle powertrain having a transmission to improve shift quality to detect the start of a torque phase of the shift based on a measured transmission input shaft torque. A torque sensor provides a signal to a controller that monitors initial rise time of the measured transmission input shaft torque. The torque sensor may be implemented by a strain gauge, a piezoelectric load cell, or a magneto-elastic torque sensor. The system may include a vehicle powertrain having an engine, a transmission coupled to the engine via a torque converter and a controller configured to initiate torque phase control when the slope of the transmission input shaft torque exceeds a predetermined threshold after initiation of the shift preparatory phase.

Abstract: A method of controlling a multiple step downshift is disclosed. Two offgoing shift elements are released and two oncoming shift elements are engaged to complete the downshift. During a first phase of the downshift, one of the offgoing shift elements controls the rate of increase of input shaft speed. During a second phase of the downshift, one of the oncoming shift elements controls the rate of increase of the input shaft speed. The method computes target torque capacities such that output torque and input shaft acceleration are continuous during the transition between phases. Furthermore, the method computes target torque capacities such that both oncoming clutches reach zero relative speed simultaneously as the input shaft reaches the final speed ratio.

Abstract: A method for controlling cylinder pressure producing piston displacement for actuating a control element of an automatic transmission during a gearshift, includes (a) applying boost pressure to the to the control valve controlling the piston, provided one of the following conditions is present a boost phase is unexpired, cylinder pressure is less than a desired pressure, and piston displacement exceeds a desired displacement; (b) applying stroke pressure to the cylinder provided piston displacement away from control element plates occurs; and (c) increasing stroke pressure provided piston displacement away from clutch plates has not occurred.