Calibration And Experimental Study Of Diesel-LNG Dual Fuel Engine

In the context of energy shortage and increasingly strict emission regulations,natural gas has been widely used in various industries due to its advantages of cleanness,large reserves and low price.Its use as an alternative fuel for traditional petroleum fuel in internal combustion engines has attracted a lot of attention and become a research hotspot.In this paper,a Yuchai YC6K450LN-C31 engine is used as the object to carry out research.First,an engine test bench is built and the maximum explosion pressure in the cylinder and exhaust temperature of the pure diesel mode are used as constraints to calibrate the diesel mass substitution rate and pilot diesel relative fuel injection advance angle of the dual-fuel mode,and then the power performance and economy of the engine in dual-fuel mode and pure diesel mode are compared.Finally,the emission characteristics of dual-fuel engine under different working conditions are studied.The results show that:(1)The diesel quality replacement rate of the calibrated dual-fuel engine is above 70%in the usual speed range of 900r/min～1200r/min;it is necessary to adjust the fuel injection advance angle of pilot diesel at medium and high loads,which is relative to that in pure diesel mode.The fuel injection advance angle needs to be further increased.(2)When the engine works in dual fuel mode,the power performance is the same as that in pure diesel mode;when the engine works in external characteristics,propulsion characteristics,and different loads at 1000r/min speed,the effective fuel consumption rate of dual fuel mode is higher than pure diesel mode,the fuel cost of dual-fuel mode is significantly lower than in the pure diesel mode.(3)In the usual speed of 1000r/min,the total number of particulate matter will gradually decrease with the increase of the replacement rate under medium and low loads,the total number of particulate matter increased at low replacement rate under high loads,when the replacement rate reached 80%,the total number of particulate matter decreased significantly.NO_x emissions decrease as the replacement rate increases at low loads,and increase at medium and high loads;HC emissions increase significantly as the replacement rate increases at each load;CO emissions increase first and then decrease as the replacement rate increases.At 50%load rate,the total number and volume of particulate matter under the selected speed conditions decrease with the increase of the replacement rate.NO_x emissions decrease with the increase of the replacement rate at lower speeds,and increase at higher speeds and higher replacement rate;HC emissions and CO emissions are all higher than those of pure diesel mode.Under common operating conditions,the engine has a higher diesel quality replacement rate,and the operating cost and particulate matter and CO2 emissions of the dual-fuel mode are significantly lower than the original engine.The use of natural gas can effectively improve the economy and emissions of the engine.