Gm Global Technolgoy Operations, Inc.

Delco Electronics Corporation

Daniel J Richardson

Vivek Mehta

Gregory J Johnson

Susan Jean Lane

Richard J Bremer

Michael Denny Parr

Charles M Grimm

William S Bowers

A digital spark timing control for an ignition system of a spark ignited internal combustion engine. Engine crankshaft position sensor, develops by way of example, three reference pulses and eighteen position pulses for each complete revolution of the crankshaft. The reference pulses are angularly spaced by 120.degree. and the position pulses by 20.degree.. A spark taming value is computed by a computer and its program is interrupted at the occurrence of a reference or position pulse. The system at the occurrence of each interrupt determines whether or not the spark is to occur in the next twenty degree period. If the spark should occcur in the next twenty degree period, the system utilizes the most recent twenty degree time period to determine how long it will take the engine crankshaft to rotate from its current position to the desired spark position. This compensates for spark timing errors that might otherwise occur due to changes in engine speed.

Spark timing control system

The torque output of a fluidic torque converter that is driven by a supercharged engine and whose output is coupled to the input of a hydraulic automatic transmission is determined and compared with a transmission input torque limit which is a function of the transmission gear. The boost pressure output of the engine supercharger is limited based on this comparison to closed loop limit the torque output of the torque converter at the transmission input torque limit.

Method of regulating supercharger boost pressure

A driver override of a cruise control system is detected and employed to suitably alter the powertrain controls. A driver override of the cruise control system is detected by a lack of correspondence between the engine throttle position and the cruise control servo position, taking into account any hysteresis and lash which may occur in the linkage coupling the servo to the throttle. The lash is determined by storing the measured servo position whenever the measured throttle position is equal to a predefined value, and the controller responds during a detected driver override by instituting normal or noncruise related control parameters. This control permits the cruise control parameters to yield smooth control without unnecessary shifting while retaining a more responsive control during driver override conditions.

Driver override control logic for a motor vehicle powertrain control

The air/fuel ratio of an engine during its open loop fuel controlled warm up period is established by one schedule while the vehicle automatic transmission is in drive and established by another schedule while the vehicle automatic transmission is in neutral.

Engine air/fuel ratio controller

A vehicle engine exhaust mounted oxygen sensor of the type producing an internally generated signal voltage and having a variable internal impedance is connected in series with a reference impedance and a semiconductor switch, the semiconductor switch having an impedance which may become large when current therethrough is very low. A constant current source is connected to supply current to the junction of the sensor and reference impedance at one sensor terminal and thus guarantee a minimum current and small switch impedance when the sensor impedance is large. Further apparatus samples the magnitudes of the voltage at the one sensor terminal with the semiconductor switch in its conducting and non-conducting states, the ratio of said magnitudes varying with sensor impedance. The ratio can be compared with one or more references to provide a warm sensor signal or control the operation of a sensor heater.

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Grand Blanc, MI, United States of America

Daniel J Richardson