Air-to-fuel ratio adjustment for internal combustion engine - responds to exhaust oxygen content with forced deviation from desired ratio until catalyst is sufficiently activated

摘要

Fuel is injected (5) into the engine (1) under the influence of an engine control unit (9) which compares the output from an exhaust oximeter (16) upstream from the catalytic converter (11) with a threshold voltage. When this is exceeded the mixt. is diagnosed as over-rich and adjusted by redn. of the quantity injected. The control unit also operates a valve (8) in the throttle bypass (7). The desired air-to-fuel ratio is related to a satisfactory purification coefft. of the convertor. ADVANTAGE - A measurable improvement in exhaust compsn. is maintainable over a wide range of conditions, with the catalytic convertor operating more effectively before the engine is warmed-up.