Research of Low Explosion Pressure and Low Fuel Consumption for Double-Wall-Jet Combustion System of DI Engine

Abstract

According to the spray characteristics and formation mechanism of NOx and soot of DI engine, a double-wall-jet combustion system of low compression ratio is designed and related experimental research is carried out. The results show that: The instantaneous heat release rate of double-wall-jet combustion system shows a trend of single peak. When the compression ratio is reduced, the starting point of combustion is postponed for about 2~3 oCA, which makes the cylinder pressure greatly reduced, the cylinder combustion temperature and NOx emissions reduced ensuring the dynamic performance of the engine. The fuel consumption rate characteristics is analyzed according to the cumulative heat release rate, the percentage of total heat release, the single peak heat release rate and the indicated thermal efficiency, it shows that the fuel consumption rate is at a very low level. To reflect the advantages of the doublewall-jet combustion system, the combustion phase of the doublewall-jet engine is consistent with that of the original one, the fuel supply time is postponed for 2oCA. The fuel consumption rate of the double-wall-jet engine is equivalence to that of the original one, the peak cylinder pressure and emissions of NOx is lower. Keywordsheat release rate; double-wall-jet; diesel;Nox; indicated thermal efficiency