Oil return to the sump of a flat engine

摘要

Returning engine oil to the primary oil sump from outboard locations in a flat engine can be a challenge. In the present disclosure, the pressure fluctuations occurring at the underside of the piston, due to reciprocation of the piston, are used to pump the oil from outboard locations to the primary oil sump. To prevent backflow of oil during periods of negative pressure difference, a check valve is placed in the oil drain passage. The check valve allows flow from the outboard location to the primary oil sump and no flow from the primary oil sump to the outboard location by opening and closing as driven by pressure fluctuations due to piston reciprocation. Such a check valve also prevents backflow of the oil to one of the outboard locations when the engine is tilted.

主权项

1. An internal combustion engine, comprising:
an engine block; a cylinder defined in the engine block; a piston reciprocating within the cylinder with a combustion chamber disposed on one side of the piston and an outboard chamber disposed on the other side of the piston; a crankshaft disposed in the engine block and coupled to the piston by a connecting rod; a primary sump coupled to the engine block; an auxiliary sump fluidly coupled to the outboard chamber; a drain passage fluidly coupling the primary sump with the auxiliary sump; and a check valve disposed in the drain passage, the drain passage and check valve together providing for flow through the drain passage from the auxiliary sump directly to the primary sump when the check valve is open.