Controlled flow cooling system for low weight reciprocating engine

Abstract

A light metal die-cast head and cast iron block employ a low volume cooling system which cooperates with the differing thermal conductivity properties of said head and block. The cooling concept eliminates the conventional intricate water jacket and replaces it with continuous grooves which wrap hemi-cylindrically about each combustion cylinder in a thinly spaced relation. The grooves are exposed along their length at the deck surface of either the head or block. The total fluid mass in the system is reduced to as little as 1/5. There are two such grooves in the block which (a) extend from one end thereof to the opposite end, (b) are on opposed sides of the cylinder galleys and (c) have substantially no transverse flow in order to promote laminar or controlled flow. There is a critically located straight drilled passage along with two such grooves in the head, the combination of which is restricted in throat area when compared to the throat area of the grooves in the block; this results in a high velocity flow in the head and a low velocity flow in the block when they are connected in series flow relation. The straight longitudinally drilled passage (which may include one or more of such passages) is located in the head separating the exhaust and metal valve guides; the passage has a throat area equal to or less than the throat area of either of the grooves in the head. Heat extraction is more easily and flexibly programmed to achieve not only a more uniform wall temperature throughout the head and block, but permit a desirably slightly higher average wall temperature than conventional light metal heads for improvement in fuel economy and thermal efficiency.