AIR-FUEL RATIO CONTROLLING METHOD FOR GASOLINE ENGINE

摘要

PURPOSE: To provide the air-fuel ratio controlling method in a carburetor capable of suppressing the discharge quantity of toxic components at the time of a light load as well as at the time of a full load. ;CONSTITUTION: An air guide port 10 is opened at the Venturi section 6 of an isobaric carburetor 4 arranged on the intake path 3 of an engine 1. The air outflow port 13 of a vacuum switch valve 12 is communicated with the air guide port 10, and an air inflow port 18 is opened on the vacuum switch valve 12. The vacuum switch valve 12 is communicated with the intake path 3 on the combustion chamber side than the throttle valve 8 of the carburetor 4, and the vacuum switch valve 12 is opened or closed by the intake negative pressure of the engine 1. When the intake negative pressure of the engine 1 becomes high, the vacuum switch valve 12 is opened to feed air to the Venturi section 6 from the air guide port 10. When the intake negative pressure of the engine 1 becomes low, the vacuum switch valve 12 is closed to stop the air feed to the Venturi section 6 from the air guide port 10.;COPYRIGHT: (C)1994,JPO&Japio