Stratified Charge Combustion at a High Pressure and Temperature Using a Constant-Volume Combustion Vessel : Development of the Combustion System and Experiments on Combustion

Abstract

A constant-volume combustion system has been developed to reproduce direct-injection stratified-charge combustion, which is regarded as a promising concept for lean combustion. A fully premixed mixture consisting of N₂, O₂ and H₂ was ignited to obtain a high pressure and temperature occurring at the top dead center in a real engine. The H₂ in the mixture is oxidized by a part of the O₂; thus, a N₂-H₂O-O₂ mixture can be prepared before the injection of iso-octane fuel. Velocities of the swirling air in the vessel were measured by hot-wire anemometry and combustion was analyzed from schlieren photographs and combustion pressures. The results show that a compromise should be achieved between burning velocity and NOx and HC emissions by adjusting the swirl level.