Methanol Dissociated Device On Vehicles And Study Of Its Influence On The Engine

With the environmental problems and energy issues becoming increasingly prominent,more and more attention is taken on the automotive industry,so the engine exhaust emissions control and substituted engine fuel demand is also increasingly urgent.As an alternative fuel,methanol has good prospects for development,and it can provide important guarantee for sustainable development of China’s automobile industry and oil crisis.It is an effective and important way to utilize methanol with methanol cracking technology.Engine Fueled with methanol pyrolysis gas is a way to recycle engine waste heat.By use of methanol cracking device,methanol is dissociated into H₂ and CO and the dissociated gas is lead into the cylinder as fuel,the original fuel calorific value of methanol is increased by 20%after dissociation,and some disadvantages of direct use of methanol is overcome,which greatly improves the fuel economy.Methanol cracking device is the key part of the alcohol-hydrogen power system,it is related to the exhaust heat utilization efficiency and affect the efficiency of catalyst.The device should recycle the waste heat as much as possible to heat the methanol proper temperature,so the catalyst can play a real role.In this paper,three kinds of methanol dissociated device with different structures were simulated by ANSYS FLUENT 15,and the temperature profile and velocity profile were analyzed,and the influence of the straight-tube and the spiral-tube methanol dissociated device on the performance of the engine is analyzed.The results show that:compared with the straight-tube and U-tube dissociated device,the spiral-tube methanol dissociated reactor performs better on heat transfer,and it can perfectly meet the requirement of the vehicle;Mixing combustion of dissociated methanol can reduce the engine torque and improve effective thermal efficiency on stoichiometric conditions.the spiral-tube methanol dissociated reactor performs better on engine performance compared with the straight-tube,with the increase of methanol substitution ratio,CO emission first decreases and then increases,HC emission decreases,and NO_x emission increases.