Abstract

A method and apparatus for controlling the various functions of an internal combustion engine using a program-controlled microprocessor having a memory preprogrammed with various control laws and associated control schedules receives information concerning one or more engine-operating parameters such as manifold pressure, throttle position, engine coolant temperature, air temperature, engine speed or period and the like. These parameters are sensed and then supplied to input circuits for signal conditioning and conversion to digital words usable by the microprocessor system. The microprocessor system computes a digital word indicative of a computer-commanded engine control operation and output circuitry responds to predetermined computer-generated commands and to the computed digital command words for converting them to corresponding pulse-width control signals for controlling such engine operations as fuel-injection, ignition timing, proportional and/or on-off EGR control, and the like. A system is provided for sensing the immediate need for acceleration enrichment (by monitoring for an abrupt increase in manifold absolute pressure or throttle angle) and an interrupt request signal is sent to the microprocessor system which responds to the interrupt request to compute an acceleration enrichment digital word which the output circuitry uses to provide an immediate additional charge of fuel, and if a fuel charge is currently being applied at the time of the interrupt request, the additional acceleration enrichment fuel charge is applied immediately upon the completion of the normally-applied fuel charge.