Control system for normalizing the air/fuel ratio in a fuel injection system

In a closed loop fuel injection system for an internal combustion engine, control system for normalizing the fuel injection system to a fixed air/fuel ratio during predetermined operating conditions, said control system comprising:

• an electrochemical exhaust gas sensor positioned in the exhaust system of the engine, said sensor having an internal impedance varying inversely with the temperature of said sensor from a very high internal impedance at its low, nonoperable temperature to a very low internal impedance at its high, operating temperature;
• a gas sensor amplifier circuit means electrically connected to said sensor, said circuit means responsive to the change in internal impedance thereof for generating an output signal having a high voltage level in response to said very high internal impedance;
• speed transducer means responsive to speed of the engine and operable to generate a pulse electrical signal having a frequency proportional to the speed of the engine;
• speed transducer circuit means responsive to said pulse electrical signal for generating an output signal having a high voltage level below a first speed;
• a delay means receiving as its input signal said high voltage output signal from said gas sensor amplifier circuit means and said speed transducer circuit means for generating a high voltage level output signal in response thereto and for maintaining said high voltage level output signal for an extended predetermined period of time after said signals are removed from the input of said delay means;
• an engine coolant transducer responsive to the coolant temperature of the engine for generating an electrical signal having a high voltage level below a predetermined operating temperature;
• wide open throttle transducer means responsive to the wide open position of the throttle of the engine for generating a high voltage output signal;
• fuel delivery control means including primary and secondary integrators each respectively having an integrating capacitor, said primary integrator normally maintaining a first air/fuel ratio and operative to maintain a second fixed air/fuel ratio and said secondary integrator normally responsive to said primary integrator for modifying said first air/fuel ratio;
• a first switch means electrically connected in shunt with said integrating capacitor of said primary integrator and responsive to one of said high voltage level output signals from said sensor amplifier circuit means, said speed transducer means, said wide open throttle transducer means, and said engine coolant transducer means;
• and
• a second switch means electrically connected in shunt with said integrating capacitor of said secondary integrator and responsive to said high voltage output signal from said delay means for maintaining the output of said primary integrator unmodified.