Study On Formation Mechanism Of Oil Film And Key Technology In Independent Lubrication Injector Of DME Engine

Dimethyl ether (DME) is a colorless, non-toxic and environment-friendly compound at normal temperature and pressure. It can be extracted and synthesized from coal, oil and gas and other resources. DME as a new clean alternative energy that replace of oil fuel is of greatest development potentiality.DME as alternative energy in replacement of oil fuel mainly performances in two areas. One is combustion with LPG. The other is replacing diesel combustion in automobile engine. DME as a substitute fuel for diesel has an important influence for the future energy strategy of china. The physical and chemical property of DME is very different with diesel. It can not be used in general automobile engine. According to the characteristics of DME, Traditional diesel fuel injector has been redesigned. DME can be best burning for this redesign. It also verified by experiment.A new injector was designed for the DME, which based on the general one. The lubrication device is added to the fuel injector, which would lower the leakage of the DME and reduce couples abrasion. Injector nozzle has also been improved, increasing the number of nozzle and the diameter of nozzle. The problem that calorific value of DME is lower than the diesel fuel was solved. In this way, DME engine can apply dynamic as well as diesel engine.When the gap of couples is filled with lubrication oil, Rim film will appear. A research about when the rim film broken was done by an experiment method. Used the software MATLAB to analysis the experiment data, and discovered the relationship between the pressure and the radius of oil film. The factors of film rupture - surface tension was determined. We also studied whether the rim film will be keeping a long-term.Fluid mechanics formula was adopted, and laminar flow model was also established, to analysis lubrication oil leakage through the couples. Compared with the injection quantity of DME, the leakage was so small. Software FLUENT was also taken to analysis the fluid flow between the couples. Made a comparison between the theoretical calculation and simulation calculation .we also had an analysis of the error.According to the viscosity relationship between lubrication oil and the DME, and the formula for the flow in traffic gap, we preliminary designed the proper pressure for the lubrication.