| 摘要 |
Apparatus for use with an internal combustion engine wherein a fuel float bowl and gasoline tank are connected through a vapor trap to the ambient atmosphere to prevent pollution by hydrocarbon vapors. The vapor trap is purged at high engine loads by an air flow through the vapor trap and into the engine, the air flow being controlled by the use of a sensor stationed along the path of the fuel or air components prior to their entering the cylinders. In a fuel injection engine of the type wherein fuel pressure varies with engine load, the vapor trap is coupled to a venturi through a valve that is opened only when the fuel pressure exceeds a predetermined value. The valve has a variable opening so that only small amounts of purge air flow through the vapor trap to the engine at moderate engine loads and large amounts of purge air flow only at very high engine loads, to provide a minimal change in the fuel-to-air ratio.
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