Closed loop mixture control system for internal combustion engine
AssigneeNissan Motor Co., Ltd.
InventorMasaharu Asano
Life of this patent
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Abstract
A closed loop mixture control system for an internal combustion engine comprises an exhaust gas sensor, a source of injecting a current into the exhaust gas sensor to develop a substantial voltage across the internal impedance thereof, and a variable reference setting circuit which establishes a variable reference voltage and reduces its value as a function of time such that the reference voltage lies between the maximum and minimum peak values of the output signal from the exhaust gas sensor.
Claims7
A closed loop mixture control system for an internal combustion engine having an exhaust gas sensor for generating a signal representing the concentration of a predetermined constituent of the emissions of the engine, said exhaust gas sensor having an internal impedance which varies inversely as a function of temperature, and means for generating a signal representing the deviation of said concentration representative signal from a reference voltage to correct the air-fuel ratio of the mixture supplied to said engine, said deviation representative signal having a first voltage level corresponding to a lean mixture condition and a second voltage level corresponding to a rich mixture condition, comprising:
- means for injecting a current into said exhaust gas sensor to raise the voltage level of said concentration representative signal, whereby said voltage level decreases from a high to a low level as a function of temperature;
- and
- means for controlling said reference voltage to lie between the maximum and minimum peak values of said concentration representative signal.
Dependencies are inferred from the claim text.