PURPOSE: To improve exhaust emission through uniform distribution of fuel mixture among cylinders and stabilize engine idling, by setting a passage bypassing a throttle valve for feeding auxiliary air.
CONSTITUTION: A bypass passage 20 is set for feeding auxiliary air, bypassing a throttle valve 6. Auxiliary air passing through air passages 20, 21 loses its flow speed and directional character while being introduced in an end passage 23 and is fed into the center of a main suction passage 2 through an air pipe 24. This makes the air feed symmetrical to the circumferential direction without drifting. As a result, the flow of fuel mixture, injected from a fuel injection valve 11 and passing through a clearance between the throttle valve 6 and a passage 2 to a suction manifold 3, is never locally disturbed by the auxiliary air and distributed uniform among cylinders of the engine.
OOMORI NORIO
SUZUKI TOMIHIDE
