Experimental Study of Rate of Heat Release of Sprays in Supercritical Direct Injection Combustion System Using Sensor

Abstract

AbstractIn present study, supercritical spray combustion and conventional (non-supercritical) spray combustion are analyzed at same experimental conditions in direct injection constant volume combustion chamber under lean burning conditions. Combustion characteristics like rates of heat release during combustion process are studied in both combustion modes using piezo-resistive pressure transducer or sensor. Commercial diesel fuel and dieseline blend (50% gasoline and 50% diesel by volume) are used for normal spray combustion and supercritical fuel spray combustion, respectively. Fuel injection pressures used are 100, 200, and 300 bar. Hot surface temperatures remain constant at 623 K and cylinder air pressures used are 20, 30, and 40 bar. It is found that rate of heat release is significantly higher in supercritical spray combustion as compared to conventional spray combustion at all experimental conditions. Which means faster combustion process occurs in supercritical spray conditions due to higher fuel–air mixing rates associated with homogenous fuel–air mixing. Hence homogeneous supercritical spray combustion is a faster and cleaner diesel combustion technology for automotive diesel engines affecting human health and environment significantly. Also, it is found that rate of heat release increases with increase in IP, but decreases with increase in CP in both combustion modes at constant HST.KeywordsRate of heat releaseSupercritical spraysHot surface ignitionConstant volume combustion chamberSensors