Experimental Study On Low Temperature Combustion Fuelled With Butanol Gasoline Diesel Blended Fuels

Traditional low temperature combustion in diesel engine adopt excessive proportion of exhaust gas recirculation to lower the combustion temperature in cylinder, then solve the serious trade-off betwen NOx and soot emissions under combustion model of diesel. But it also cased the increase of CO and HC emissions and combustion instability, deteriorated fuel consumption. The mixing of n-butanol alcohol and diesel fuel can possess lower cetane number, and then the retarded ignition delay period can contribute to mixing of fuel and air.Meanwhile due to the oxygen content of fuel, it can significantly improve the soot emissions of low temperature combustion, but the fuel consumption is not ideal. It can ensure the high thermal efficiency and lower emission characteristics if burning blends of the high calorific value and volatility of gasoline and diesel fuel. Therefore, with the integrated use of EGR and injection strategy, this paper realized the low temperature combustion basing on characteristics of the butanol and gasoline. The design of fuel was used to study the influence law of low temperature combustion and emissions on diesel engine with experiment of bench test.This paper has carried on the experimental which study the effect of combustion control parameters on the low-temperature combustion, performance and emissions with pure diesel. Results indicated that, with lower inlet oxygen concentration, peak pressure of in-cylinder dropped gradually, combustion process delayed, ignition delay prolonged, NOx emissions reduced substantially, the soot emission increased first and then decreased; with the main injection time advancing, the CO emissions and the thermal efficiency improved effectively. Added pilot injection reduced the ignition delay of main phase, heat release phase advanced, peak value of heat release rare got down, the combustion noise and NOx emissions were restrained effectively, but the smoke and CO emissions increased. In order to further improve NOx and soot emissions, and ensure the thermal efficiency, the low temperature combustion experiment was carried out basing on blended diesel of butyl alcohol and gasoline. Comparison results show that, the bended fuel can simultaneously reduce NOx and soot emissions at moderate levels of EGR rate. Combined with multiple injections and EGR, the unstable combustion of blended fuel has been solved as the single injection time delayed, the fuel consumption still increased with the reduction of low calorific value. It can improve simultaneously the soot and NOx emissions at suitable pilot injection mass and pilot-main interval, but induced rise of CO. Compared with the results of butanol/diesel and gasoline/diesel fuel, it can compromise the contradiction between the emissions and fuel consumption when mixing of butanol and gasoline in the diesel fuel together. This kind of fuel implements new efficient and low emission combustion model on low temperature combustion.