Supplemental fuel vapor system

Claim 1

A supplemental fuel system utilizing fuel vapor, comprising: an internal combustion engine including a carburetor and an intake manifold; a fuel tank provided with air vents; a fuel conduit having a first end connected to said fuel tank and in communication with liquid fuel in said tank and a second end connected to said carburetor; said fuel conduit delivering said liquid fuel to said carburetor from said fuel tank; a fuel vapor conduit having a first end connected to said fuel tank at a location displaced from contact with said liquid fuel and a second end connected to a carbon canister; a PCV conduit having a first end connected to a pollution control valve and a second end connected to said intake manifold; and, an intermediate fuel vapor conduit having a first end connected to said fuel vapor conduit and a second end connected to said PCV conduit; wherein said air vents continuously provide air to said tank to mix with said liquid fuel and form fuel vapor, said fuel vapor drawn from said fuel tank by vacuum developed in said intake manifold and flows through said fuel vapor conduit, said intermediate fuel vapor conduit and said intake manifold to combustion chambers of said internal combustion engine so as to supplement fuel delivered to said engine by said fuel conduit, said liquid fuel and said fuel vapor constantly delivered to said engine during normal operation.