An Overexpanded Two-Stroke Constant-Pressure Cycle for Developing Fuel Efficient and Low Emission Engines

A new overexpanded two-stroke constant-pressure engine cycle (the “OTCP Cycle”) has been developed to achieve the twin goals of lower engine out emissions while at the same time achieving increased fuel economy. A low-temperature combustion process lowers engine out NOx emissions. A high expansion ratio provides increased thermal efficiency for greater fuel economy. A two-stroke configuration provides a large power density for reducing mechanical losses per unit power.