Experimental Study About Performance Of Engine Of Electronic Controlled Dual Fuels Of Dimethyl Ether-Diesel

With the developing of national economy and the increasing of automobile quality, the shortage of petrol is becoming more and more severe, and the emission of exhaust gas from internal combustion engine becomes one of chief source of pollution in the large cities. As a rising regenerated sanitary fuel, Dimethyl Ether (DME) has gained the attention of the entire world. The IEA/AMF(International Energy Agency,Implementing Agreement:Alternative Motor Fuels ), a allied research community about Dimethyl Ether, has been established. There are ten government department, researching institution and companies who attend this researching project. By the effort in several years, the member of the IEA/AMF accomplished the research effort about the feasibility of the DME as one automobile fuel. At present, the research about DME fuel has enter applied stage in many country.Aimed at the characteristic of energy in our country, it has great strategic significance to develop the alternative fuel of the DME that can be draw out from coal, nature gas, coal gas stratum and nature matter, shape the alternative fuel system of the diesel engine that adopt to the situation of our country for alerting the energy structure of our country and decreasing the dependent on the petrol and ensuring the energy safety of our country. It is one of the effective ways that extend the apply of the new DME fuel to alter the nervous situation of producing energy and consumption.Now the special spraying pump of the DME is not mature. It is difficult that the pure DME is used on diesel engine. The DME were directly mixed with diesel as the fuel of the diesel engine will bring the promble which is the engine work unsteadiness. And that adopt the measure which is"low pressure supply gas and imbibe gas mixed"supply the DME. It will still supply the DME when minish engine accelerograph and appear phenomenon which is engine fall speed slowly. Also it is difficult control the blended combustion ratio under every engine working condition. In this paper we took a new technical scheme which is electronic single injection gaseity the DME.The idiographic scheme is: the DME stored in steel bottol fuel box with liqued state. At first, passed through evaporator which made it become gaseity form, the evaporator meet hot cycle water of engine pledged requirement of heat quantity with the DME boiloff, then passed through electronic the DME injector, entered intake pipe of Diesel engine, mixed air entered combustion chamber participated in burn. The spray quantity of the DME controlled by electronic the DME electronic cell.Based on project, the study contents are as follows.1. The DME electronic controlled single injection in intake pipe system was designed. The single-point electric controlled injection system for DME was designed in this paper. The signal of engine speed and throttle opening are read by the ECU. Then, the DME injection pulse width outputted after inquiring the MAP table. Besides, the injection pulse width can adjusted online to realize the precise control on the hybrid combustion ratio of DME and diesel.It can make the DME/diesel blend combustion ratio was controlled accurately.2. Experimentation study of the DME/diesel blend combustion on Jatta SDI Diesel. The results of the study are as follows.1) The influence of injection amount of DME on the emission: Along with the DME injection width goes up, the emission of HC is increased; the emission of NOx is decreased and the emission of soot is trivial increased and the emission of CO is increased under the midding and light load; the emission of NOx rise and then fall and the emission of soot fall and then rise and the emission of CO is immovability under the 100% load.2) The influence of injection amount of DME on the combustion: Along with the DME injection width goes up, the start of igition is advanced, the pressure improvement ratio is increased in compression stroke. The tendency for crude operation was decreased too. It will make combustion deterioration and compress minus work increased while blend combustion ratio of the DME/diesel is too large under different load. It will assume two moment exothermic characteristic obviously on the map of burning exothermic reaction ratio in the section. So it need optimize control when blend burn under every working condition.3. The DME/diesel blend combustion ratio is optimized in engine working bound. The DME working injection width is confirmed. The torque and emission of optim engine is measured. Aslo compare with the original engine. The results of the study are as follows :1. Changing of relation between torque and paddle position on optimize engine and original engine is linearity, pledged working smooth character of optimize engine.2. In engine whole working rangs, the economic characteristic and the power characteristic is as same as original engine.3. Compared with original engine, the emission of NOx is trivial decreased, the emission of soot is trivial increased, the emission of CO and HC is increased.4. According to the DME injection width MAP, electronic DME-diesel blend fuel engine is tested on automobile. The software and hardware of electronic DME single injection system is designed. Diesel saloon car which refit the DME is tested on rim test-bed. The result indicated that the acceleration character of diesel saloon car which refit the DME isbetter than origin car and the smoothness is good. The emission satisfied demand of GB18352.2-2001"Limits and measurement methods for emissions from light-duty vehicles(â…¡)".