Heat transfer unit

Claim 1

A heat exchanger for internal combustion engine in which fuel-air mixture is preheated by exhaust gases; a hollow housing structure; inlet and outlet exhaust gas conduit means extending from said hollow housing; means defining an inlet manifold portion in said housing with which said inlet exhaust means is in direct communication; means defining an outlet manifold portion in said housing with which said outlet exhaust gas means is in direct communication; a plurality of elongated tubular elements extending between said inlet and outlet manifold portions and being in communication with the same; and fuel-air inlet and outlet openings in said housing on opposite sides of said tubular elements such that the fuel-air mixture entering its inlet and leaving its outlet is heated by the exhaust gases flowing through said tubular elements; said hollow housing being defined by at least two parallel walls in which said fuel-air inlet and fuelair outlet are disposed and aligned apertured portions in said parallel walls through which fastening means may extend; said tubular elements being generally rectangular in cross-section with a pair of diagonal corners of such rectangle being aligned in a direction extending from said fuel-air inlet to said fuelair outlet; and discontinuous web portioNs interconnect adjacent tubular elements and also discontinuous web portions interconnect said tubular portions to internal wall portions of said hollow housing.