The Research On The Performance And Discharge Of Diesel-DME Blends On The Diesel Engine

This paper presents a brief introduction to the situation of domestic and international resources. After a careful analysis of the situation, we come to know the huge resource pressure, the shortage of petroleum and environmental pollution in particular. Therefore, in addition to various energy-saving measures, a new generation of energy should be found in the use of motor to utilize the existent resource more effectively, and it will be a new way to reduce the excessive dependence upon petroleum resource. Dimethyl Ether(DME), as a substitute fuel, displays huge developmental potential. And this is in accordance with our country's condition, conductive to fully take advantage of our abundant coal resource.Currently, the application of DME in diesel engine is still in research stage, while the research on combustion performance blended with DME is instructive to development and optimization of diesel engine. The paper shows a systematic discussion about 3D math mold and calculation method of values in the process of in-cylinder work. FIRE software developed by AVL Corporation in Australia is used in this paper to conduct out the creation and web partition and generation of geometric mold, and verify the chosen calculation mold. Apart from those, simulation calculation of was engaged in the process of air fluid in engine with different DME ration, atomization and combustion; velocity distribution in-cylinder, spray development, temperature field and density filed of combustion are shown in detail.The comparison about in-cylinder pressure of diesel-DME blends, temperature field and density field of diesel-DME blends leads to tranquil combustion in diesel engine blended with different ration of DEM, which is a great help to weakening of noise and decrease of machine load. Since no C-C bond exists in DME structure with the lover boiling point, easy vaporization and high-quality of spray atomization of diesel fuel, it is conductive to obstruct the formation and soot omission. Meanwhile, DME is characterized by a higher cetane number, good ignition performance, reduced ignition delay and premixed combustion, so there was the most combustion pressure and lower temperature in cylinder to inhibit the formation of NO_x. On the other hand, due to the higher latent heat value compared with diesel fuel, the evaporation process demands a great amount of thermal energy and reduces the in-cylinder temperature, which to some degree also prohibits the NO_x formation.