| The increasingly stringent vehicle emission regulations and the gradual reduction of oil storage in China,the application of unconventional fuels in internal combustion engines has become a hot topic of major automobile manufacturers and research institutions in China.Methanol and biodiesel have many advantages,such as wide source,low price,convenient production,good power and economy,and clean emissions.They have great advantages as alternative fuels for diesel and gasoline.This paper adopts methanol and biological diesel dual fuel injection combustion mode,namely methanol in port injection formation of premixed gas,bio diesel cylinder direct injection ignition of methanol premixed gas,methanol with high octane number,high latent heat of vaporization and high cetane number of biodiesel and sixteen characteristics of both oxygen,is conducive to broaden the premixed combustion ignition load limit mode.On the engine bench,the performance tests of methanol/biodiesel dual fuel engine were carried out on the original engine fueled with 0#diesel and biodiesel engine performance test,and the parameters such as the proportion of methanol injection,engine compression ratio and fuel supply advance angle of biodiesel were tested.The results showed that compared with 0#diesel engine,the Biodiesel Engine’s power performance was similar,the maximum cylinder pressure,the maximum pressure rise rate and the maximum temperature increased,while the emissions of CO and HC decreased,while PM and NO_X emissions increased slightly.Methanol premixed gas biological diesel engine combustion mode,the heat release rate curve shows the characteristics of"Shuangfeng"in the high load condition,increase cylinder pressure,pressure rise rate and heat release rate increased with the mass ratio of methanol combustion parameters increasing,low load,the change law on the contrary.When the compression ratio is reduced,the starting point of combustion is delayed,and the burst pressure,pressure rise rate and maximum combustion temperature increase first and then decrease with the decrease of compression ratio,while the instantaneous heat release rate increases.At low speed,the change of fuel supply advance angle makes the combustion pressure,instantaneous heat release rate,pressure rise rate and maximum combustion temperature decrease.At high speed,these combustion parameters increase with the increase of oil supply advance angle.In methanol after combustion thermal efficiency of the engine effectively increases the compression ratio decreases,low thermal efficiency low engine load decreases first and then increases,high speed and high load thermal efficiency is decreased,the engine fuel supply advance angle increased to promote the effective thermal efficiency improvement.With the increase of methanol mass ratio,NO_X emissions decrease,particulate emissions increased firstly and then decreased,increased HC and CO emissions;fuel supply advance angle is increased to reduce NO_X emissions,and fuel supply advance angle change of HC and CO and particulate emissions can not restrain,compression ratio to reduce NO_X emissions have decreased a certain effect,but will increase HC and CO and particulate emissions.To sum up,this paper uses biodiesel to ignite methanol premixed gas combustion mode,which can alleviate the problem of heavy load and rough combustion,and has a certain inhibitory effect on NO_X emissions,but the effect of THC and CO emissions on small load is not very obvious.This study provides a theoretical basis for the application of methanol and biodiesel in diesel engines. |
