Abstract: A system for controlling a torque converter clutch in a vehicle powertrain includes a controller having an input for receiving powertrain operating parameter information. The controller is configured to determine a torque converter speed ratio based on the powertrain operating parameter information and to compare the speed ratio to a specified speed ratio limit. The controller is further configured to determine a target torque converter slip when the speed ratio exceeds or meets or exceeds the specified speed ratio limit; to compare the target slip with a desired slip value based on an vehicle noise, vibration or harshness (NVH) limit; and to control torque transmission of the torque converter clutch based on comparison of the target slip and the desired slip value. A method for controlling a torque converter clutch is also provided.

Abstract: In a method for characterizing a road surface beneath a moving vehicle whose powertrain includes a torque converter coupling the engine to a driven wheel, a set of successive values for the torque converter's slip error rate is generated using filtered values for engine speed and torque converter turbine speed. The road surface characteristic is identified based on the set of slip error rate values, as through a comparison of the set with a plurality of case statements, wherein each case statement corresponds with a different road characteristic and/or general surface type. Weighted average values are calculated based on subsets of the values within the set, for use in identifying transitions from one type of surface to another, or one surface characteristic to another. Indicated slip error rates generated in response to changes in an engine torque demand request are also identified to avoid a false indication.

Abstract: In a method for characterizing a road surface beneath a moving vehicle whose powertrain includes a torque converter coupling the engine to a driven wheel, a set of successive values for the torque converter's slip error rate is generated using filtered values for engine speed and torque converter turbine speed. The road surface characteristic is identified based on the set of slip error rate values, as through a comparison of the set with a plurality of case statements, wherein each case statement corresponds with a different road characteristic and/or general surface type. Weighted average values are calculated based on subsets of the values within the set, for use in identifying transitions from one type of surface to another, or one surface characteristic to another. Indicated slip error rates generated in response to changes in an engine torque demand request are also identified to avoid a false indication.

Abstract: A system for controlling a torque converter clutch in a vehicle powertrain includes a controller having an input for receiving powertrain operating parameter information. The controller is configured to determine a torque converter speed ratio based on the powertrain operating parameter information and to compare the speed ratio to a specified speed ratio limit. The controller is further configured to determine a target torque converter slip when the speed ratio exceeds or meets or exceeds the specified speed ratio limit; to compare the target slip with a desired slip value based on an vehicle noise, vibration or harshness (NVH) limit; and to control torque transmission of the torque converter clutch based on comparison of the target slip and the desired slip value. A method for controlling a torque converter clutch is also provided.

Abstract: A method of carrying out open loop variable line pressure control of hydraulic fluid in a vehicle transmission, wherein an electro-hydraulic valve is used to adjust line pressure. Duty cycle values are updated as a function of transmission hydraulic fluid temperature when the transmission is under closed-loop line pressure control. The updated duty cycles are applied to drive the electro-hydraulic valve when the transmission is under open-loop line pressure control. Preferably, the duty cycle values are also updated as a function of battery voltage.

Abstract: A vehicle powertrain has an engine coupled to an electronically-controlled automatic transmission. A method for controlling the vehicle powertrain during a transmission shift from a neutral gear to a drive gear detects a change in a signal indicative of a desired transmission gear change from a neutral gear to a drive gear. An engine idle speed is reduced by a predetermined RPM in response to the change in the signal. The transmission is shifted from the neutral gear into the drive gear upon the engine idle speed being reduced by the predetermined RPM.

Abstract: A method for synchronizing a plurality of pedal position sensors in a motor vehicle. A series of voltages are accumulated from each of a plurality of pedal position sensors. Representative voltages are determined from the series of voltages. The representative voltages are assigned to linear relationships from which an offset is determined.

Abstract: A method for synchronizing a plurality of pedal position sensors in a motor vehicle. A series of voltages are accumulated from each of a plurality of pedal position sensors. Representative voltages are determined from the series of voltages. The representative voltages are assigned to linear relationships from which an offset is determined.

Abstract: A method and system for sharing a hardware resource in a multistate system is provided. The method includes the steps of monitoring changes in state in the multistate system using a pickup device, accessing a memory containing control parameters required by the hardware resource in response to a state signal from the pickup device, applying a control signal that is related to the accessed control parameters to the hardware resource, and connecting the hardware resource to a selected one of several output devices.

Abstract: A method of sensing and determining open circuits and short circuits to the solenoid-actuated valves for the electronic automatic transmission.