Intake manifold

Claim 1

An intake manifold assembly for an internal combustion engine including exhaust gas conduit means and utilizing a carburetor having primary and secondary passage means through which an airfuel mixture is delivered to said engine, said assembly comprising a housing receiving said air-fuel mixture from said carburetor, means defining said housing with a primary manifold passage in direct flow communication with said carburetor primary passage means and with a secondary manifold passage in direct flow communication with said carburetor secondary passage means, said primary and said secondary manifold passages being defined over at least portions thereof by a pair of sections having a generally concave cross-sectional configuration each including a pair of laterally extending flanges at which said concave sections are joined together, means defining a heating section contiguous to said primary manifold passage, with a wall extending to separate said heating section and said primary manifold passage, said wall defining on one side thereof a portion of the interior of said primary manifold passage and on the opposite side thereof a portion of the interior of said heating section, said wall being formed on said opposite heating section side with a plurality of heat transmission fin members extending into said heating section, means connecting said heating section in flow communication with said exhaust gas conduit means to direct exhaust gases from said engine into said heating section thereby to effect heating of said air-fuel mixture flowing in said primary manifold passage by heat transmission from said exhaust gases, and heat insulation means extending to insulate said primary manifold passage from said secondary manifold passage to block transfer to said secondary manifold passage of the heat transmitted to said primary manifold passage from said exhaust gases, said heat insulation means being mounted between said laterally extending flanges to separate said primary and secondary manifold passages, with gasket means being provided between said flanges and said insulating means, said assembly being configured and arranged with said heating section located on one side of said primary manifold passage and with said secondary manifold passage and said insulation means located on an opposite side thereof remote from said one side.