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 absolute 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 into digital words usable by the microprocessor. The microprocessor system computes a digital command 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, or the like.

Abstract: A single point fuel injection system for an internal combustion engine including a throttle body having first and second air intake throats corresponding to first and second intake manifold planes of the engine, the air flow through each throat being controlled by throttle plates positioned within each throat. The throttle body further includes a fuel accumulating bowl which is integrally formed with the throttle body, the bowl being enclosed by a diaphragm and cover member. Within the enclosure of the fuel bowl are positioned a pair of injectors which are adapted to inject pulsed portions of fuel through a sonic nozzle and into the air intake throat of the throttle body. The injection of pulses of fuel into the throat is timed in accordance with the sensing of the crankshaft reaching a position of 15.degree. before top dead center to enhance the distribution of fuel charge from cylinder to cylinder.

Abstract: A single pressure sensor is caused to provide a pressure measurement at two separate pressure regions through the use of a differential pressure switch whose switch over point occurs when the two regions are at a fixed pressure differential or offset. The sensor is connected to sense a first region with a sensor output signal being compared to a signal related to the count in a counter. Upon switch over the counter is actuated to make a signal equal to the sensor output signal. The counter signal, compensated for the offset, is related to the pressure at the second region.