Study On Emission Characteristics Of A Multi-point Injection Methanol/diesel Dual-fuel Engine

In the context of fossil fuel shortage,serious environmental pollution and soaring automobile quantity,methanol as a kind of renewable clean energy has important research significance.The test of this paper is conducted on YC6G270-30 high pressure common rail diesel engine,by adding a methanol supply system,a methanol injection system and a methanol injection electronic control system to realize the mixing combustion of methanol and diesel,and by the scanning mobility particle sizers SMPS 3938 to measure the number and mass concentration distribution of the exhaust particulate matter.And then the influence of blending ratio,load,diesel injection timing and methanol stop cylinder on the particulate number and mass concentration,PN,CO,HC,and NOx of methanol diesel dual fuel engine is studied.Through the experimental research and analysis,the following conclusions are obtained:1)With the increase of methanol blending ratio,the amount of particulate matter concentration,mass concentration,the PN emissions ratio are decreased,and the peak of the particle number distribution moves to the small particle size direction.At the same time the number of nuclear membrane state particles increases,while the number of accumulation state particles decreases.Meantime,the emissions of CO、HC and NOx are declined.2)With the increase of engine load,the particle number concentration and PN emission go up first and then go down.The range of particle size distribution is broaden,and the peak of number distribution moves to large diameter direction.The number of accumulation state particle ratio and particulate mass concentration increase.At the same time,the CO and HC ratio emissions decrease,and the trend of NOx emission is not obvious.3)As the diesel injection timing is advanced,the concentration and the PN emission ratio of the particles becomes lower first and then higher,and the peak of concentration is moving towards the smaller particles,and the concentration of mass is dropping.At the same time,the CO and HC ratio emissions decrease first and then increase,and NOx ratio emission is higher than before.4)Compared with the no stopping fueling mode,the number concentration and PN emission is higher than stopping fueling mode.And the peak of particle number concentration moves to the small particle size direction.The particle mass concentration of nuclear membrane state increases.At the same time,CO and HC ratio emissions reduce and NOx emission increases.In addition,in the stopping fueling mode,the effective fuel consumption rate decreases and the fuel economy improves.