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 charge forming system is disclosed which monitors a parameter of engine combustion efficiency, such as power output, and derives a signal indicating the sense of power change. A fuel mixture control system responds to an indication of increasing power to continually and progressively lessen the fuel/air ratio to attain the leanest possible mixture consistent with maximum instantaneous engine power output. In a preferred embodiment liquid fuel is vaporized before delivery to the engine combustion chambers, and a variable orifice provided to enhance the flow characteristics of the vaporized fuel.

Abstract: A method and apparatus for controlling an internal combustion engine by a digital computer. A pulse generator for generating reference pulse signals in synchronism with the rotation of the crankshaft of the engine is associated with the digital computer which is programmed to discriminate the rotational speed of the engine is higher or lower than a predetermined value in response to the reference signals and digitally calculate a required amount of fuel to be supplied to the engine or the like.

Abstract: An electronic control unit for regulating the air/fuel ratio of an internal combustion engine is disclosed. The electronic control unit has an open loop calibration for regulating air/fuel ratio that is corrected with a closed loop signal developed by an integral controller. The integral controller bases the closed loop correction signal on a signal from an exhaust gas composition sensor located in the engine exhaust manifold. Various conditions of the system are sensed by a closed loop sensor condition detector to provide information on whether the sensor is up to operating temperature and is operative. If the exhaust gas sensor is functioning and the operating system parameters indicate the system operation should move to closed loop control, the loop is closed by the condition detector. Included in the condition detector circuit is a timer whose cycle is RPM dependent.

Abstract: An electronic control unit for regulating the air/fuel ratio of an internal combustion engine is disclosed. The electronic control unit has an open loop calibration for regulating the air/fuel ratio that is corrected with a closed loop correction signal developed by an integral controller. The open loop calibration is a speed-density based schedule which is combined with corrections for special conditions to account for the operating parameters of the engine at any instant. Included in these special condition corrections are provisions for an altitude compensation feature. The altitude compensation feature includes circuitry to modify the intake manifold pressure portion of the speed density schedule with two variables which depend on altitude.

Abstract: A hybrid electronic control unit for regulating the air/fuel ratio of an internal combustion engine is disclosed. The electronic control unit is divided into two functionally distinct parts including an analog function generator and a digital function generator. The analog function generator receives analog signals to process efficiently by analog scaling, amplification, multiplication, and division while the digital function generator receives digital and logic inputs to process efficiently by addition, subtraction, and comparison. The analog function generator interfaces with the digital function generator by an analog signal from a D/A converter and other unconverted digital output signals from the digital function generator. Preferably, the analog function generator provides an open loop air/fuel ratio calibration based upon a speed density calculation including special condition corrections to the base calibration.