Spray Characteristics And Study On Common Rail Diesel Engine Of Biodiesel

Today, the mineral resources like oil are very shortage all the world. Over-exploitation; lack of offshore oil development technology; uneven distribution of resources and other factors, which have been made the oil more precious. Our country is rich in oil resources. But per capita consumption is less than the world average. The increase of the number of the cars bring heavy pressure to resource requirements and environmental of our country. Beijing has controlled the rapid growth of car by controlling the car sales. So looking for energy saving, environmental protection, renewable alternative energy sources is imminent. As a representative of the alternative energy, Biodiesel is valued by scientists with its mature technology; rich source of raw materials; significantly reduce pollutant emissions; mitigation of greenhouse effect.In the research background of Chongqing Natural Science Foundation of―bio-diesel development‖, an examination use DK4 diesel engine as the experimental prototype to developing bio-diesel engines. In order to study the impact on the engine by the biodiesel . Firstly, use of simulation software AMESim to carry out on the common rail injector model. In order to analyze the physical and chemical properties of biodiesel that impact on the various parameters of the injection that provide the basis for the later. Secondly, after reference to the large number of foreign research results, this paper completed experimental study of spray with biodiesel and fossil diesel fuel, which captured the process of the spray with the high-speed photographic equipment. The results show: comparison with mineral diesel, the spray tip penetration of biodiesel is longer and the spray angle is smaller. Because of the density and viscosity of biodiesel are bigger than diesel. This paper also introduce the SMD (sauter mean diameter), explained the reason why the spray of biodiesel is poor from the microscopic view.After the two-step analysis above, this paper completed the study of the ignition delay, the combustion and emission experimentation with the blend fuel of biodiesel and diesel. Experimental results show that due to the cetane number, compression pressure and temperature increase, the ignition delay decrease with the percent of biodiesel in the blended fuel. The combustion experiments results show that the heat release rate of biodiesel is earlier than diesel, and the maximum heat release rate is larger, which also verified the previous changes on the ignition delay. When study the engine power and economy, we find that the fuel consumption of the biodiesel increase, and the torque reduction. The percent of biodiesel in the blended fuel also impact on the exhaust and the pressure after intercooler. The emission examination focuses on the NO_X emission of the biodiesel. The results show that the EGR technology can control the high NO_X emission. The final conclusion shows that the injection advance angle and the EGR rate adjustment can reduction in soot emissions when the NO_X emissions not obvious increase.Full-text research provides the relevant theoretical conclusions, part of the contents will be further exploration and study.