Abstract: An internal combustion engine with a plurality of cylinders operating in a four-stroke mode, with pistons moving with reciprocating motion, employs at least one holding tank shared among a plurality of cylinders, and wherein the holding tank conveys a pre-combustion gas (fuel-air mix in gasoline engines) from the cylinders via a return manifold for reinsertion into an intake manifold of the engine. Valving extracts a quantity of pre-combustion gas from a cylinder into the holding tank during a compression stroke for subsequent discharge into the return manifold to reduce the compression ratio to a value less than the expansion ratio.

Abstract: An internal combustion engine, having a cylinder with a translating piston therein, employs a holding tank connecting, via a valve, to the combustion chamber of the cylinder for receipt of a portion of the engine gasses expelled during a compression stroke for providing that the expansion ratio of an expansion stroke is greater than the compression ratio of the compression stroke. The holding tank is located within a head of the cylinder, and has a single port serving for both ingress and egress of gasses to the combustion chamber. The holding tank is provided with one or more additional passages for connection to one or more additional cylinders in the event that the holding tank is shared among two or more cylinders.

Abstract: An Elevated Expansion-Ratio Internal Combustion Engine has a substantially standard repeating four-stroke sequence for each of a plurality of cylinders. The head of each cylinder has an intake valve, a combustion-gas exhaust valve, and a vapor return valve. A return manifold for vapor connects from respective ones of the cylinders via a plurality of valve assemblies, each of which includes the return valve, into a passage ahead of a beginning portion of an intake manifold. Each valve assembly also has a discharge valve coupled to the return valve via a holding tank for cylinder vapor or gas. Valve stems of the discharge and return valves are coaxial in a single section valve housing or spaced-apart in a two-section valve housing. A quantity of the vapor is received into the holding tank during the compression stroke, and subsequently transferred via the discharge valve to the return manifold.

Abstract: An internal combustion engine having a timing device for advancing operation of an exhaust valve, and a method of operating the exhaust valve, wherein, for the case of a conventional automotive engine, the timing device opens the exhaust valve less than 90 degrees before bottom dead center in a terminal portion of the power stroke of the engine, but more than approximately 30 degrees before the bottom dead center. The engine is a four-stroke engine, and the open interval of the exhaust valve extends from a terminal portion of the power stroke into the exhaust stroke. The advancement in the opening of the exhaust valve reduces fuel consumption.