Experimental Study Of Hydrogen And Addition Of Hydrogen To Natural Gas On A Spark Ignition Engine

Energy and Environment are two major issues in the world. Production and human life continually consume fossil fuels on the earth. With the development of automobile industry and vehicle population, pollution and shortage of energy are aggravated. Hydrogen is a promising substitute for fossil fuels because it has many advantages, such as multiple sources, renewable, clean, and so on. Therefore, studies on engine performance and emissions fueled with hydrogen are of great significance on the development of hydrogen engine.The thesis discussed different hydrogen-fuel engine mixture formations, abnormal combustion phenomena and suppression techniques, analyzed NOx formation mechanism and influencing factors. Relevant researches were also studied in this paper.Testing apparatus which was suitable for hydrogen fuel was set up. Performance and emissions of hydrogen engine were investigated. Based on experimental study of hydrogen engine above, effects of addition of hydrogen to natural gas on engine performance and emissions were investigated.Results show that for pure hydrogen fuel, combustion duration is short and cylinder pressure and heat release rate increase sharply due to fast flame propagation velocity of hydrogen. Peak values of cylinder pressure and heat release rate are high. Atλ=1.1, peak pressure is 4.3MPa, and combustion duration is 12°CA. Hydrogen engine has wide lean burn limit. Atλ=3, peak pressure is reduced to 1.7MPa and NOx concentration is approximately zero. Addition of hydrogen to natural gas is an effect way to enhance combustion of natural gas. At the same conditions, combustion duration of natural gas blended with 30%vol hydrogen is 20°CA less than that of natural gas. Peak pressure and NOx concentration increase as addition of hydrogen to natural gas, but it can be reduced by lean burn and optimizing ignition timing. Natural gas blended with 30%vol hydrogen can work stably atλ=1.857. Peak pressure is reduced to 1.57MPa and NOx concentration is less than 50ppm due to extension of the excess air ratio.