Variable displacement arrangement in four cycle, reciprocating internal combustion engine

Claim 1

In a four cycle, reciprocating, internal combustion engine having a cylinder, a piston reciprocable in said cylinder, means for introducing a fuel mixture into the cylinder, means for igniting the fuel mixture, means for exhausting the burned gases from the cylinder, an engine crankshaft, and compression spring means acting between said piston and said crankshaft to cause crankshaft rotation in response to piston reciprocation, the improvement which comprises: means limiting the expansion of said spring means to compress the latter with a force at least substantially equal to the piston force required to compress the fuel mixture in the cylinder for proper combustion when the engine is under substantially no load, whereby said spring means provides a substantially stiff coupling between the piston and the crankshaft when the engine is under substantially no load and provides a resiliently compressible coupling when the engine is under substantial load; said spring means being compressible between said piston and said crankshaft substantially in proportion to said substantial load on the engine.