Research On Performance Of Low Calorific Value Gas Engine

Energy is the development foundation of all social industry, and transportation andelectric power industry are closely related to the people’s daily life. The world energycrisis and environment problem have been calling the reform of the energy industrymore and more. Traditional non-renewable fossil energy such as oil, coal and otherreserves are reducing day by day, so the government’s and extensive scholar’s attentionare attracted by the renewable biological energy sources. Among them, the research ofbiomass gasification gases that obtained through controlled pyrolysis and as fuel of thetraditional internal combustion engine has been becoming a focus.Based on GT-Power simulation, the comprehensive performance of the engine,which fueled with the gasification gas obtained through controlled pyrolysis from woodflour, was predicted. A model was built based on GT-Power software to anatural gasengine of EQD210N-20. The model was validated by the cylinder pressure distributionand the full load speed characteristics of the engine，and used to predict the performanceof power, economy, emission and exhaust of the engine fueled with the wood flourgasificationgas, and optimize the engine’s parameters. The performance of biomassgasification engine was compared to a natural gas engine to get laws of the gap. In orderto improve the engine performance, adding natural gas to the wood flour gasificationgas was simulated. Making use of the gasification gas engine in the system of combinedcooling heating and power, some adjustments under different conditions were studied.It is shown that ignition advance angle, burning equivalent ratio, the throttle valveand the composition of the fuel are the important factors which affect the biomassgasification gas engine. For the biomass gasification gas engine, the maximum cylinderpressure decreases with the decrease of the ignition advance angle. It increases firstlyand then decreases with the increase of air-fuel ratio. Its best value is near2.5. There arethe best ignition advance angle and air-fuel ratio for effective brake pressure, torque,power and other dynamic parameters, they are about10°CA of the anchor angle（50%fuel were burned）and near2.5respectively. The ignition advance angle has little effecton brake specific fuel consumption, the minimum of brake specific fuel consumption isat the ignition advance angle correspond to the anchor angle （50%fuel were burned）of about10°CA and at the air-fuel ratio of3.The generation amount of NOxdecreaseswith the decrease of the ignition advance angle, and larger amount of NOxgeneratedwhen the air-fuel ratio is among2.5to3.5. Exhaust gas temperature increases with thedecrease of ignition advance angle, it increases firstly and then decreases with theincrease of the air-fuel ratio, its maximum value is near the air-fuel of2.5.The massflow rate of exhaust gas is almost not affected by the ignition advance angle, whichincreases with the increase of the air-fuel ratio. Adding natural gas to biomass gasification gas fuel can improve the engine power, economy and exhaust conditionseffectively. Different demands of the CCHP system can be realized by adjusting the gasengine. Different supplies of electricity and heat and cold energy of the CCHP systemfor the user can be achieved by changing the throttle, the ignition advance angle and theair-fuel ratio.