Method and device for adjusting engine exhaust gas recirculation control
 The actual air-fuel ratio of a combustible mixture supplied to an engine is sensed and is compared with a set desired air-fuel ratio which corresponds to a desired ratio of the amount of engine exhaust gases recirculated into the intake system upstream of the carburetor to that of intake air drawn into the engine. An exhaust gas recirculation control valve is operated in dependence on the difference between the actual and desired air-fuel ratios to change the flow of exhaust gases to control the actual ratio of the amount of exhaust gases recirculated into the intake system to that of engine intake air to the desired ratio. 
Nissan Motor Co., Ltd.
Y F
Y02T F02D
additional inventional
Hidehiro Masaaki
Minami Saito