Numerical Simulation And Experimental Study Of Combustion Characteristics Of A Direct Injection Engine Fueled With Low Heating Value Gas-Hydrogen Blends

With the developing of automotive industry, the shortage of fossil fuels and the environmental deterioration had become the most important problems that human facing. In recent years, gas engine has widely become the focus of mainly engine researchers all over the world, but the work of direct injection engine fueled with low heating value gas is at the incipient stage in China.In order to master the combustion characteristics of a direct injection engine fueled with low heating value gas-hydrogen blends, this research takes the modified engine ZS1100M as a prototype, and studies the combustion characteristics of a direct injection engine fueled with low heating value gas-hydrogen blends. So it can help to design the gas engine fueled with low heating value gas, and it also can supply the corresponding control strategy and basis.According to the structure and operation parameters of this gas engine, the geometry model of combustor, turbulence model, boundary conditions and initial condition applied in the combustion simulation are determined. Comparing with experimental date, the results of numerical simulation are credible and veritable.Combustion characteristics of a direct injection engine fueled with low heating value gas-hydrogen blends under different ignition timings and various injection timings are simulated in this paper, it analyses the cylinder pressure, temperature field and NOx concentration field. The results show that there are some different features of combustion characteristic of fueled with low heating value gas-hydrogen blends.The experiment of combustion characteristics of a direct-injection spark-ignited engine fueled with low heating gas-hydrogen blends under various ignition timings and injection timings and various excess air coefficients are investigated. The mean pressure, torque, rate of heat release, HC emissions, CO emissions, NOx emissions, the gas consumption rate and thermal efficiency are analyzed. The results of the study show that it can increase the power and economy of engine fueled with low heating gas-10%hydrogen blends under appropriate ignition timings and injection timings. At the same time, it also shows that the different load characteristics under various nitrogen fractions.