Abstract: A fuel injection system for an internal combustion engine having integral action regulation for influencing the fuel-air mixture supplied to the engine includes an exhaust gas oxygen sensing probe, two regulating stages, and an electronic control unit all connected in circuit to provide a signal to the fuel injection valves directly or to an electromagnetic pressure control valve in the circuit of the fuel injection valves for varying the fuel quantity injected and consequently the fuel-air mixture to the engine.

Abstract: Control systems in which transition between oxidizing and reducing state of the exhaust gases is sensed, and the input to the engine modified in accordance with sensed exhaust gas composition utilize a sensor which has an output signal having a transition jump, the extent of the jump being highly temperature dependent; in accordance with the invention, a signal is derived representative of change in level of the transition jump, as a function of temperature, and the control circuit responsive to the transition jump, and controlling input to the engine is modified in accordance with the signal repesentative of level change of the transition jump, to compensate for temperature-dependent changes.