A microcomputer emissions control system

A single chip microcomputer system has been developed to control and protect three-way catalyst equipped 6 cylinder vehicles. The system incorporates a carburetor mounted stepper motor actuator, secondary air control and self-diagnostics. A unique scheme has been used to sense various engine modes which does not require an analog to digital converter. This paper presents a description of these features, a brief outline of present program strategy and future development considerations.