Gm Global Technolgoy Operations, Inc.

Peter M Medich

Robert Charles Simon, Jr

David C Poirier

Richard A Marsh

Joseph M Tolkacz

George C Mitchell

Grant William Brady

Daniel B O'Connell

Patrick J Westphal

Richard C Mamolen

Robert C Cameron

William G Polom

Janet M Koch

John A Calkins

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.

Engine coastdown control system

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.

Method of preventing spark plug fouling

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.

Method of learning gain for throttle control motor

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.

Engine throttle stop control system

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.

Engine idle speed control with feedforward power adjustment

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Birmingham, MI, United States of America

Peter M Medich