Abstract: A transferable electronic control unit having a non-volatile memory that retains values of learned correction factors for control parameters used in adaptively controlling the operation of a vehicle is disclosed. The electronic control unit receives an identification signal from the vehicle in which it operates. By comparing the value of the received identification signal with a stored value identifying the vehicle operated when learning the values of the correction factors that are stored in non-volatile memory, the electronic control unit determines whether or not it has been transferred between vehicles. When a transfer between vehicles has not occurred, the value of the learned correction factors stored in non-volatile memory are used to begin adaptively controlling vehicle operation. When a transfer between vehicles has occurred, initial or mean values for the correction factors are used to begin adaptively controlling vehicle operation.

Abstract: A fuel vapor canister is purged by admitting fuel vapor from the canister to the vehicle engine under control of a solenoid valve, the duty cycle of the valve being controlled to optimize the purge rate. Closed loop fuel correction and block learn fuel correction factors developed by the fuel control system are used to update a learned purge duty cycle which is stored in a keep-alive memory.

Abstract: When the throttle of a vehicle engine is released by the vehicle operator of a vehicle having an automatic transmission, the slip of the automatic transmission is measured and the airflow of the engine is trimmed as a function of the measured slip to establish a desired drive-on feel of the vehicle during coastdown.

Abstract: The fuel control routine of an engine control module sets a cold enrichment schedule used for engine starting when the engine is cold. The enrichment value is dependent on coolant temperature. To prevent plug fouling in a new vehicle subject to short engine run times, the enrichment value is reduced if the mileage is below 50 miles, the coolant temperature is within set limits and the previous engine run time was shorter than a set period.

Abstract: An idle speed control motor under computer control positions a throttle stop for setting minimum throttle angles. The motor response to actuating pulses varies from motor to motor so that a gain factor is determined for each motor and is used to calculate the required pulse width to attain a desired throttle displacement. A gain learn program in the engine control computer runs when the ignition is turned off and is effective to extend the motor with a number of pulses of known width, measure the throttle displacement, and determine the gain factor by dividing a standard displacement by the measured displacement. The same program is applied to learning the gain of a throttle motor in an electronic throttle control system.

Abstract: In a method of traction control, fuel injectors are selectively disabled to unfuel respective cylinders of an engine to reduce engine torque output. The method provides for limiting the number of cylinders that can be disabled for acceleration spin control based on engine and vehicle operating parameters to improve traction control performance and provide protection for the vehicle catalytic converter.

Abstract: A communication method provides for an exchange of a multiple byte message between two processors. Interrupt suppression associated with the message transfer is minimized by alternating the processors between master and slave operating modes with each byte exchanged.

Abstract: The ratio air and fuel mixture delivered to the fueled cylinders of an engine of a vehicle is controlled while selective cylinders of the engine are unfueled to reduce engine torque output to inhibit excessive wheel spin during vehicle acceleration. The air/fuel ratio of the mixture delivered to the fueled cylinders is increased as cylinders are selectively unfueled to reduce engine torque output and power enrichment to the fueled cylinders is inhibited when any cylinders are unfueled to reduce engine torque output for traction control and for a time period after all cylinders are again fueled.

Abstract: A throttle follower controller for establishing a release throttle position upon the release of the throttle by the vehicle operator which is maintained at a specified value for a predetermined time if the vehicle transmission is experiencing an upshift or if an upshift will occur upon the release of the throttle to provide for a smooth upshift. Upon completion of the upshift or if no upshift will occur upon release of the throttle, a controlled transition of the throttle angle to a predetermined lower coastdown value is established to prevent drive-on while preventing a sudden harsh drive line jerk upon release of the vehicle throttle.

Abstract: Potentially damaging operation of a viscous converter clutch (VCC) is detected in relation to the slippage thereacross. The slippage is compared with a reference slip value indicative of excessive VCC slippage to develop a net overslip indicator. The value of the net overslip indicator changes in the direction of a first limit value so long as the detected slip is at least as great as the reference slip, and in the direction of a second limit value so long as the detected slip is less than the reference slip. When the net overslip indicator reaches the first limit value, the friction clutch is disengaged to release the VCC. According to a first embodiment, the transmission fluid temperature at the time of such deactivation is measured and stored, and the VCC is reactivated when transmission fluid temperature falls below the stored temperature, assuming other criteria for activation are also met.

Abstract: A feedforward throttle adjustment for a closed loop idle speed control provides engine power output required to drive a variable power steering load while maintaining the engine idle speed in a desired range. The working pressure of the power steering system is detected, and the change in such pressure in the course of a steering maneuver is used to initiate an increase in the engine power output setting. The increase is determined in relation to the peak pressure change; it is implemented at a pedetermined rate, and is subject to interruption whenever the pressure change indicates that the steering maneuver has ended.