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Direct-Injection, 4-Stroke Gasoline Engines, the Orbital Combustion Process Solution
Published December 03, 1997 by Institution of Mechanical Engineers in United Kingdom
Environmental pressures on the global goal for reduced greenhouse gases has produced a resurgence in the interest in highly efficient automotive engines, including direct-injection, lean-burn stratified charge powerplants. This paper discusses how Orbital's Combustion Process (OCP) with its low-pressure, air-assisted, direct-injection technology has been demonstrated to offer significant fuel economy improvements over the conventional manifold-injected systems, whilst showing the potential to meet the tightening emissions constraints for future European and USA markets. Specifically the authors also discuss the tolerance of the stratified charge combustion process to high diluent levels which have enabled very low engine-out NOx emissions to be achieved simultaneously with low engine-out hydrocarbon (HC) emissions. Fuel economy benefits of up to 20.1% over the European Drive cycle simulation have been measured on a 4-cylinder test engine in a 1360 kg ITWC vehicle, while maintaining overall engine-out NOx emissions less than 0.25 g/km, and HC emissions equal to the manifold-injected engine