Reciprocating internal combustion engine

Claim 1

A reciprocating internal combustion engine, comprising: a cylinder having a substantially horizontal axis and having one end thereof shaped as a combustion chamber and the other end thereof opening into a crankcase adapted to receive a lubricating atmosphere, said cylinder having a bottom zone where liquid lubricant may collect when the engine is stationary; a piston slidable in said cylinder and having a space therein communicating with said crankcase, said piston having an outside surface formed with at least one peripheral sealing groove and a peripheral scraper groove, said peripheral grooves being of rectangular cross-section with a base and a pair of transverse surfaces, said scraper groove being nearest said other end of said cylinder and having the base thereof formed with orifices via which said scraper groove communicates with said space in said piston; a substantially rectangular cross-section piston ring received with a reduced clearance in each said sealing groove; and a substantially rectangular cross-section scraper ring received with a reduced clearance in said scraper groove; said piston being received in said cylinder with clearance whereby annular gaps are formed between said outside surface of said piston and said cylinder on each side of each of said piston and scraper rings; in which engine the improvement comprises: each said sealing groove being provided with first narrow passage means providing a continuous communication between the base of said sealing groove and said annular gaps on both sides of said piston ring in said sealing groove; said scraper groove being provided with second narrow passage means providing communication between the base of said second groove and at least that annular gap which is on the side of said scraper ring nearest said one end of said cylinder; both said first and said second passage means being disposed at a level above said bottom zone of said cylinder.