Experimental Study On Combusiton And Emission Characteristics Of A Diesel Engine Fuled With Gasoline/Diesel Wide Distillation Range Blended Fuel

HCCI, A new generation of internal combustion engine combustion technology which can reduce NOx and PM emissions at the same time by using premixed, compression ignition and low temperature combustion. Ignition timing control and broadening a wide range of loads are the main problems to be solved for HCCI combustion. Using two or more different and complementary fuel mixture as fuel is considered to be one of the effective methods to control HCCI combustion process.In this paper, gasoline and diesel was blended with a volume proportion of1:2. The blended fuel was boiled with ranges of40-240℃(F24),40-270℃(F27) and40-300℃(F30) in a distillation kettle to get the three test fuels. An experimental study on combustion and emission characteristics of the three test fuels was conducted on a diesel engine. The test engine was a four-cylinder inline turbocharged diesel engine, equipped with BOSCH second generation of electronically controlled high pressure common rail fuel injection system.The results shows that, comparing with those of pure diesel(F1), the peak combustion pressure and the maximum pressure rise rate of the F24, F27and F30increased, the corresponding crank angle delayed. F24has a longest ignition delay, while F1got shortest. The ignition timing of F27and F30are almost the same. With a130MPa rail pressure,30mg fuel injection quantity(56%load), the engine have a better performance fueled with pure diesel F1than F24and F27. F30got a better performance than F1under the same condition. F24, F27and F30have a lower smoke emission than F1. The NOx emission order from most to least of the four fuels is:F24>F27>F1>F30.As the intake air temperature rise, the ignition timing of F24, F27and F30advanced, the maximum pressure rise rate reduced, peak heat release rate decreased, peak combustion pressure decreased, smoke emission increased, NOx emission reduced at first and then increased.As the injection pressure increase, the ignition delay of F24, F27and F30shortened, the maximum pressure rise rate increased, CA50advanced, peak heat release rate increased, peak combustion pressure increased. With a low engine load(32%), the engine power reduced slightly as the injection pressure increase, while the engine power increased when the engine load increases. The smoke emission of F24, F27and F30reduced and NOx emission increased.As start of injection advanced, peak combustion pressure of F24, F27and F30increased, the crank angle at which the peak heat release rate advanced, the ignition delay period presents a similar u-shaped curve, the maximum pressure rise rate increased significantly. The engine has a best performance when Fuel injection angle at-5℃A ATDC. The smoke emission of F24, F27and F30reduced and NOx emission increased significantly. As the fuel pilot injection quantity increased, the pilot injection peak heat release rate of F24, F27and F30increased, ignition timing advanced, peak combustion pressure increased, peak heat release rate reduced, engine power reduced, smoke emission reduced and NOX emission increased. As the pilot injection timing advanced, the peak combustion pressure of F24, F27and F30decreased, the maximum pressure rise rate increased. Engine power, smoke emission and NOX emission of F24, F27and F30reduced.