Design And Development Of Intelligent Combustion System For Low Emission Methanol Diesel Dual Fuel

With the rapid development of economic society as well as the shortage of fossil resources and environmental pollution,the consumer demand of oil and other fossil fuels is increasing.Due to the shortage of oil resources,serious environmental pollution and the surge in the number of cars,the methanol,a kind of petroleum alternative fuels,has broad prospects and will play a very active and important role.According to the combustion characteristics of methanol and diesel,this thesis proposed a new mode of hybrid combustion.Under the situations of starting a car or small load,engine only use diesel,however,under the medium and high load situations,engine use methanol and diesel.This mode can save diesel and improve the fuel economy,besides the emissions of HC and CO and NOx also can be reduced significantly.In order to improve the average replacement rate of methanol to diesel and ameliorate the quality of engine emission,a method of controlling different working situations is presented,which realized the control of spray methanol length in different situations using the appropriate strategy.So the replacement rate reached more than 30 percent and the emissions of harmful gases significantly reduced.The ECU was designed through PIC16F876 A microcontroller.It can accurately judge the dual fuel engine working situation by collecting and analyzing the parameters of the engine.In order to monitor and debug parameters,the upper computer was designed.The upper computer can be used to calibrate the sensor parameters and display the engine parameters in real time,and also can adjust the methanol parameters according to different working conditions of the engine.In order to solve the problem of discretizing the parameters collected from the upper computer,the interpolation algorithm was used in the ECU software programming.This algorithm can transform the three-dimensional dispersed data into continuous data,so as to achieve a smooth MAP graph.In order to mix the methanol and diesel oil full in engine,this thesis designed a spray nozzle,which can form the homogeneous mixture from the mist methanol and air.The methanol and diesel oil can be effectively separated,so the engine can be switched to the pure diesel combustion mode or the dual fuel combustion mode.It has been proved that the system is safe by the engine experiments.This system was installed on the load carrier which used Weichai engine.By tracking and recording the usage of this system,the average replacement rate of methanol to diesel was improved and the emissions were significantly reduced.It has shown that this system can improve the fuel economy,save diesel and reduce pollutant emission.