Characteristics Study On DME Engine Independent Lubrication Injector

Dimethyl Ether (DME) has many advantages, such as high efficiency, low emissions, lownoise, smokeless and so on, which make it a promising alternative fuel in diesel engine. With itsunique physical-chemical characteristics, when applying it in diesel engine, the NOx emissioncan be lower, and nearly smokeless. That effectively solves the contradiction which can notreduce PM and NOx emissions at the same time. However, when using DME in traditional dieselengine, needle coupling can be severely worn in a short period, due to the low viscosity of DME.As a result, serious leak comes out and finally needle coupling can not work normally.In order to solve the problem above, our research group has developed independentlubrication injector, based on DME engine low-pressure fuel delivery system. Compared withtraditional injector, an independent lubrication system is added in this new injector. And needlecoupling in motion can be lubricated, which confirms injector continuously works effectively. Sothat the wear and leak problems in injector when using DME in traditional injector, are solved.The new injector includes lubrication line and lubrication chamber, which makes it possible toleak lubricant into pressure chamber during the lubrication process of needle coupling. As aresult, the leak characteristics of this injector should be analyzed deeply.The main components of DME engine low-pressure fuel delivery system and theirprinciples are analyzed in this paper, according to which, the simulation model of this system hasestablished by AMESim. The working characteristics and leak characteristics are mainly deeplyresearched systematically. With the methods of comparison and optimization, the optimizationresults, including the construction parameters of independent lubrication injector and theoperating conditions, are gained. The work and leak characteristics are also analyzed aboutoptimized injector, and the results show that, the work characteristics are well and it can meet therequirement of reducing leakage. Besides, the analysis with variable parameters is also done inthe DME engine low-pressure fuel delivery system, and the related measures to reduce leakageare proposed. The researches above on one hand provide theoretical guidance of engineering forindependent lubrication injector, on the other hand, settle foundation for the research of wearmechanism in next step.Test-bed of independent lubrication injector working characteristics has been set up, andwear test-bed program has been designed in chapter four, whose purpose are to prepare forresearches of following performance test on injector, as well as the wear mechanism of injector.