Nippondenso Co., Ltd.

Sigenori Kitajima

Akira Masuda

Hideaki Norimatsu

Akio Kobayashi

Toshio Kondo

Mitsuo Nakamura

A closed-loop air-to-fuel ratio control system having an oxygen responsive sensor and a feedback circuit. The sensor is disposed in an exhaust passage to produce a voltage indicative of the oxygen concentration in the exhaust gas. This voltage is integrated in the feedback circuit with the integration constant predetermined to vary with respect to the time. Air-to-fuel ratio of the mixture to be supplied to the engine is corrected to the predetermined air-to-fuel ratio in response to the integrated voltage. With the integration constant decreasing with respect to the time, the air-to-fuel ratio is speedily returned to the predetermined ratio.

Method and system to control the mixture air-to-fuel ratio

A closed loop air-to-fuel ratio control system having an oxygen responsive sensor and a feedback circuit is disclosed. The sensor is disposed in an engine exhaust passage to produce a voltage indicative of the oxygen concentration in the exhaust gas. This voltage is integrated in the feedback circuit to cause the mixture air-to-fuel ratio to be corrected in response thereto. The integration is controlled by the integration controller to shift the mixture air-to-fuel ratio to the one other than the stoichiometric ratio. This integration controller can be made responsive to specific engine operating conditions such as throttle valve movement.

Method and system for controlling the mixture air-to-fuel ratio

An internal combustion engine having an air-fuel mixture supply controller is provided with an air-to-fuel ratio detector for detecting the oxygen content in the exhaust gas of the engine and a feedback controller for correcting mixture supply operation of the mixture supply controller in response to the oxygen content. A halt circuit and a hold circuit, being responsive to first and second operating conditions of the engine respectively, are connected to the feedback controller to halt and hold the feedback control, thus causing the mixture supply controller to supply the richer or leaner mixture as desired.

Growing community of inventors

Kariya, Japan

Sigenori Kitajima