Chrysler Corporation

John P Lappington

Leroy Shafer

An electronic engine control system comprises a central microprocessor integrated circuit, a program memory integrated circuit, and a programmable read only memory integrated circuit. The central microprocessor integrated circuit carries out calculations used in controlling an event associated with the engine according to a basic program contained in the program memory integrated circuit. The programmable read only memory integrated circuit is programmed to tailor the basic program contained in the program memory integrated circuit for the particular engine with which the electronic control system is utilized.

Programmable read only memory for electronic engine control

Mass production of electronic control units for engines

In one embodiment, a circuit parameter of a sensor varies in accordance with an input useful in controlling an event associated with operation of an engine, for example, spark timing. The sensor is connected in an input sensing circuit characterized by a first order differential equation exhibiting an exponential transient whose time constant is representative of the circuit parameter, and hence of the input being sensed. A step function input is applied to the sensing circuit to cause the occurrence of an exponential transient, and concurrently a digital counter circuit begins counting clock pulses. The transient is compared against a predetermined reference, and when a predetermined relationship between the reference and the transient is attained, the counter circuit ceases counting pulses. The accumulated count is in the form of a binary word which may be used directly by a digital microprocessor in calculations for controlling the event.

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Huntsville, AL, United States of America

John P Lappington