Abstract: A system for increasing the amount of fuel injected into an internal combustion engine in response to an increase in the manifold absolute pressure greater than a predetermined amount and greater than a predetermined rate. The amount of enrichment is equal to a first value determined by the engine coolant temperature increased by a factor that has an initial value determined by the rate of increase in the manifold absolute pressure and that is varied toward unity at a rate determined by engine temperature. The duration of acceleration enrichment is determined by the amount of change in the manifold absolute pressure and the engine coolant temperature.

Abstract: A motor vehicle combustion engine has exhaust apparatus including a sensor for sensing exhaust content therein and fuel control apparatus determining fuel supply to the engine in accordance with an engine operating condition and a trimming factor which is a function of the engine operating condition, the values of the trimming factor corresponding to different values of the engine operating condition being chosen to help maintain a predetermined exhaust content. The engine and fuel apparatus are characterized by a transport delay between the time a change is initiated in fuel supply and the time a resulting change in exhaust content can be sensed.

Abstract: A digital closed loop fuel control system for an internal combustion engine having a zirconia sensor which provides a signal changing abruptly between first and second values as the air/fuel ratio varies through a stoichiometric ratio. The output of the zirconia sensor is sampled at constant frequency sampling intervals and an up/down counter is set in one of its counting modes as a function of whether the air/fuel ratio is less than or greater than the stoichiometric ratio. During each sampling interval, a first number of clock pulses from a clock pulse generator are coupled to the up/down counter when the air/fuel ratio is greater than a stoichiometric ratio and a second number of the clock pulses are coupled to the up/down counter when the air/fuel ratio is less than the stoichiometric ratio.