Internally cooled high compression lean-burning internal combustion engine

摘要

An internally cooled internal combustion piston engine and method of operating a piston engine is provided, with the combination of liquid water injection, higher compression ratios than conventional engines, and leaner air fuel mixtures than conventional engines. The effective compression ratio of the engines herein is greater than 13:1. The engines may employ gasoline or natural gas and use spark ignition, or the engines may employ a diesel-type fuel and use compression ignition. The liquid water injection provides internal cooling, reducing or eliminating the heat rejection to the radiator, reduces engine knock, and reduces NOx emissions. The method of engine operation using internal cooling with liquid water injection, high compression ratio and lean air fuel mixture allow for more complete and efficient combustion and therefore better thermal efficiency as compared to conventional engines.

主权项

1. An internal combustion engine for use with a hydrocarbon fuel with at least one cylinder and a reciprocating piston therein, at least one air intake valve, at least one exhaust valve, and a fuel handling system with at least one fuel injector, said engine comprising:
a water injector coupled to a water source for injecting liquid water into the cylinder; a programmed control device configured for controlling internal combustion engine operations, said programmed control device receiving one or more real-time temperature values in said engine and responsively adjusting an amount of water injected and an air to fuel ratio provided to the said at least one cylinder, said programmed control device controlling actuation of said liquid water injector to inject an amount of liquid water into the cylinder at a time from about 1800 to about 300 before Top Dead Center (TDC) of said piston during a compression stroke, said liquid water injector injecting an amount of water greater than the amount of water that is present at the saturation point of water vapor in the ambient air in the cylinder and up to about 800% w/w of the amount of fuel being injected in the engine cylinder; and wherein the air to fuel ratio provided to said at least one cylinder is greater than stoichiometric, and the engine has an effective volume compression ratio greater than about 13:1.