Research Of Air Supply System Of The Dual Fuel Engine Burnt Diesel And The Methanol Cracked Gas Decomposed By Exhaust Heat

In the new century, the energy crisis and environmental pollution become increasingly serious. Clean energy of internal combustion engine became the focus of the world. Methanol is an excellent alternative fuel for internal combustion engine. Cracking the methanol into hydrogen rich gas and co-firing it in the diesel engines, to a certain extent, overcome problems of alcohol applied in the diesel Engine,improve the thermal efficiency and emissions of diesel engines.Designing a air supply system of the dual fuel engine burnt the methanol cracked gas decomposed with exhaust heat and diesel, Including exhaust heat decomposition of methanol reactor, the exhaust heat recovery system , cracked gas pretreatment system .Also introducing the composition and working principle of electronic control system of multiple point injection of methanol cracking gas and the overall design of electrical control unit. System decomposed methanol with electric heating and exhaust heat, in this way, enhance the controllability of the reactor. The pretreatment system completes the purification and compression of the cracked gas, in this way, meeting the conditions for co-firing the cracked gas in the diesel engine. Through the system of multiple point injection, the cracked gas inject at multiple point in the diesel engine.The methanol cracking reactor consist of sub-buffer zone,main cracking zone, evaporation cracking zone, Correspondingly fill in, the Cu-Cr catalyst particles(d = 3.5mm),the modification Cu-Cr-Mn catalyst particles(d=2.5mm),the same number of particles of the SiO2 and Cu-Cr mixed catalyst particles (d = 3.5mm).Reaction system rely on exhaust-pass pipe heat of absorber and methanol cracking reactor to absorb heat for Cracking,also combine electric heating,use pulse signal control injection of battery valve to feeding methanol,in this way,the controllability of reaction conditions enhance. The reaction system was tested on 6300ZC diesel engine. The results show that,only use the exhaust heat of diesel engine to heat the reactor,at medium to high loads,the appropriate reaction temperature of the reactor is 3100C,the optimal feed rate of methanol is 127.5 L.h-1and the cracking rate of methanol can reach 84.5%, the volume of CO and H2 is high in the cracked gas.Applying the air supply system in the 6300ZC diesel Engine ,testing the combustion and emissions performance of diesel engine. The results show that, when the quality percentage of the premixed methanol cracked gas is between 2.5% and 5.0%, saving rate of diesel consumption can reach 5% to 8% under the different load of diesel engine, integrated rate of thermal efficiency is obviously improved, fuel consumption declining with the blended concentration of the cracked gas increased. Compared with the original machine, NOX and soot emissions significantly improve, HC exhaust also significantly reduced, CO emissions increased slightly. In the high-load, NOX emissions can be reduced 37.6%, soot emissions can be reduced 43.5%.