| In the recent years,the use of alternative fuels in spark ignition engines has gained considerable attention due to the ever increasing gasoline fuel prices and the enforcement of strict emission regulations.NG seems to be one of the promising substitutes for fossil fuels in the future owing to lower emissions and higher thermal efficiency.However,the engines operated on CNG fuel generally suffered from engine power decline and NOx emissions increasing.Some attempts to improve volumetric efficiency by directly injecting NG(liquid phase)fuel into the combustion chamber and the charge burn rates of NG through adding hydrogen in NG fuel have been made to offset the above issues on engine power decline and NOx emissions increasing.But at the same time it brings the increasing of NOx emissions at high engine load,further cost and complexity.In order to overcome the above issues,a 5A+gasoline engine was modified into a natural gas/gasoline dual-fuel engine by adding a natural gas fuel supply system on intake minfold.The effects of natural gas ratio on the engine performance were studied by numerical simulation using GT-power.The main work are as follows:1.The specifications and operating condition of the gasoline engine used for modeling were obtained through data investigation.2.A simulation model for natural gas/gasoline dual-fuel engine was established.3.The effects of natural gas ratio on the power performance,economics performance,and combustion characteristics of natural gas/gasoline dual-fuel engine were studied.4.An analysis of the fuel costs on the various natural gas ratio were conducted.The results show that the with the increasing of narural gas ratio,maximum combustion pressure and the maximum pressure rise rate are reduced,the power performance decrease,the economy performance is improved,and the fuel cost is reduced.This study provides a theretical basis for the development of natural natural gas/gasoline dual-fuel engine. |
PDF Full Text Request