Cummins Engine Company, Inc.

Steven N Cusick

John H Stang

An oil cooling system for an internal combustion engine (2) includes a cylinder liner (22) shaped to form an annular oil flow passage (36) by an inner flow control surface (52) and outer flow control surface (56) through which engine lubrication oil flows in a very thin film under laminar flow conditions to produce a very large convective heat transfer coefficient of 300-400 BTU's per hour-feet squared-degree Fehrenheit. To insure laminar flow conditions, the radial thickness of the annular flow passage 36 is held to less than 0.016 inches and is preferably in the range of 0.008 to 0.010 inches. The disclosed liner (22) is very accurately positioned within a cylinder bore (8) of the engine block (4) by liner stop means (68) for retaining the liner in a fixed axial position within the cylinder bore (8) and by inner and outer radial locating means (106 and 101) positioned, respectively, inwardly and outwardly of the inner flow control surface (52). Annular oil supply passage (30) and oil collecting passages (66) are also formed to supply and collect, respectively the cooling oil to cause the oil to flow within the flow passage (36) inwardly from the outermost portion of the liner (22) toward the crankshaft (6) for no more than about 40 percent of the total axial length of the liner (22). A secondary combustion gas seal (96) is provided to allow leaked combustion gases to be removed by the cooling lubrication oil.

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Columbus, IN, United States of America

Steven N Cusick