Exhaust cooling system for internal combustion engine

A compact exhaust cooling system for an internal combustion engine comprising:

• a unitary exhaust manifold adapted to be mounted to the engine block of an internal combustion engine for receiving hot exhaust gases therefrom, said manifold having an integral manifold cooling jacket including coolant inlet means and a manifold outlet including a gas discharge port encompassed by a flange with one or more coolant discharge ports in said flange;
• an elbow duct having an inner tube and an outer tube connected at an inlet end by an inlet flange, said duct terminating at its opposite end in a circular doomed gas distribution header, said header including an inner dome connected to said inner tube and an outer dome connected to said outer tube so as to define between said inner and outer tubes and domes a continuous elbow cooling jacket fully enveloping said inner tube and said inner dome from said inlet flange to a dome rim connecting said inner and outer domes, said inlet flange having coolant inlets into said elbow cooling jacket in alignment with said manifold coolant outlets such that coolant from said manifold jacket flows into said elbow cooling jacket and returns to the engine through one or more coolant return ports in said header near said rim while engine exhaust gas flows from said manifold gas outlet into said inner tube and inner dome;
• a heat exchanger comprising a vessel having an upstream end, a downstream end and plurality of straight mutually parallel gas tubes extending through said vessel and supported by weld joints to said ends, said tubes open at each said end exteriorly to said vessel, said header being connected at said rim to said upstream end for supplying engine exhaust gas to said gas tubes, and means for circulating coolant through the interior of said vessel in heat exchanging contact with said gas tubes for cooling the exhaust gas passing through said gas tubes, said gas tubes having axially corrugated thin metallic walls adapted for ready axial thermal expansion and contraction without placing substantial strain on said weld joints, whereby relatively short straight gas tubes may be reliably welded to said vessel ends;
• and whereby the hot exterior surfaces of all exhaust gas conduits from said engine block to said downstream end of said heat exchanger are fully and continuously jacketed with circulating coolant and thus effectively shielded against contact with flammable substances in the engine operating environment.

An exhaust cooling system for an internal combustion engine comprising:

• an exhaust manifold unit adapted for mounting to the engine block of the internal combustion engine for receiving exhaust gases from the engine, said manifold including an integral cooling jacket for cooling the exposed surfaces of said manifold;
• a heat exchanger for cooling exhaust gases from the engine, said heat exchanger characterized by a coolant vessel, gas tubes extending through said vessel for carrying hot gases therethrough from an upstream end to a downstream end in heat exchanging relationship with a coolant medium circulating through said vessel;
• and
• an intermediate gas conduit connected for carrying hot exhaust gases from said manifold to said heat exchanger, said gas conduit being double walled between said manifold and defining between said walls a continuous cooling jacket fully eneloping said conduit, said conduit connecting to said manifold so as to receive coolant medium from said manifold cooling jacket, whereby all exposed surfaces of said manifold, said intermedite gas conduit, and said heat exchanger are shielded by circulating coolant medium against heat from engine exhaust gases to permit safe engine in proximity to flammable substance.