PURPOSE: To reduce the cost of production, by installing each air-fuel signal generating device in two exhaust systems, respectively, while setting up an air-fuel ratio feedback control device which gets controlling the air-fuel ratio at both lean and rich sides.
CONSTITUTION: At both first and second exhaust systems, there is provided with each device which detects specified component thickness in exhaust gases, then discriminates between rich and lean in the air-fuel ratio in an engine, and generates both first and second air-fuel ratio signals. An air-fuel ratio feedback control device gets controlling the lean side of the air-fuel ratio in the engine at a time when both these first and second air-fuel ratio signals come into being rich, while it gets controlling the rich side of the air-fuel ratio in the engine at a time when both these first and second air-fuel ratio signals come into being lean. Thus, a feedback control system and a suction system are put together in one system through which the cost of production is reduced.
SUEMATSU TOSHIO
ANZAI KATSUSHI
ITOU YOSHIYASU
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