Experimental Research On The Scheme Of Control The Ratio Of Blending Diesel Oil With DME In Diesel Engine

With the great attention increasingly given to pollution,restriction of internal combustion engine emission in many countries become more and more rigorous. Dimethyl Ether(DME) is a new and promising alternative fuel with ultra low emission in the world. All the tests on various diesel engines show that DME can make diesel engines engine work more efficiently withultra low emission and smokeless combustion.On consideration of the low production ,high production cost and transportation cost of DME ,The research work described in this thesis focuses on diesel engines operated with diesel fuel blended DME,This can make full use of both the property of atomization of DME and the property of lubrication of diesel oil. In this way,not only the emission of diesel engine can be reduced,but also the problems of wear and leak brought by combusting pure DME can be resolved.With the cooperation of Guangxi Yucai Machine Co. Ltd,a DME blending control system aiming at the diesel engine of the type of YC6108QC developed. In this control system,Some small modifications on low-pressure oil way are made by adding a DME blending device. Under the system,the diesel engine can shift fast between pure diesel oil and diesel oil blended with DME conveniently. Moreover,the control and adjustment of blending ratio of DME in some range can be achieved in this system.In this thesis,the design scheme of this system and the specific configuration of mechanical and electronical part are described. The election of important components and the design of blending tank are also explicated. In this control system Personnel Computer (PC) works cooperatively with Single Chip Micyoco (SCM),which integrated the well interactive ability of PC with the field working ability of SCM. The SCM communicating with PC via (COM) port. During the design of interface circuit,electromagnetic valve driving circuit and main electronic control unit,standardization andmodularization technology are used. Meanwhile,In view of the characteristics of hardware and diesel engine,modern software engineering technologies are employed to deploy the system resources rationally in the process of developing software.First,the fluxes of electromagnetic valve are measured fully via test;and consequently the detail implementation schemes for blending ratio of DME from ten percent to twenty percent are established. This control system has been used on the diesel engine of the type of YC6108QC for bedtest. The results show that the system has better controllability and reliability and it can meet the expected requirement and control blending ratio of DME in realtime mode successfully.