Experiment Of Reformed Methanol Gas Engine

With the rapid development of China automobile industry, petroleum resources shortage and environmental pollution have become increasingly serious. Therefore, it's urgent to find alternative fuels of petroleum. Methanol is one of the most promising alternative fuels because of the characteristics of high oxygen content, sufficient combustion and low harmful emissions. Because of the abundant coal resources in China, the methanol which can be obtained from coal can provide a large number of fuels for china automotive industry.There are many disadvantages for liquid methanol which is used in internal combustion engine, such as the corrosion on metal, swelling action on rubber and cold start problems. These problems have seriously restricted the application of methanol fuel in internal combustion engine. However, these problems can be resolved or reduced by reforming methanol. The research of reforming methanol in engines has caused more and more attention.An engine-reformer system was designed, and an EFI gasoline engine was reconstructed. The liquid methanol was heated, evaporated, and dissociated into hydrogen and carbon monoxide with the presence of catalyst by exhaust energy. Reformed methanol gas (RMG) was transported to engine cylinder. It was analyzed that the performance of RMG engine through experiments, such as characteristics of the engine-reformer system, the composition of RMG under different conditions, emissions, and combustion process in the cylinder.The experimental results show that RMG includes hydrogen, carbon monoxide, dimethyl ether, methyl formate and methanol steam, and these gases account for more than 95%. The time when the engine-reformer system works depends on environmental temperature and engine conditions. In real application, there are available measures for reducing the time through covering heat insulation materials on the system and adjusting ignition timing of engine. In the condition that the engine is not optimized, thermal efficiency of RMG can reach up to 34%. The excess air ratio can reach up to 1.8. The engine provided clean exhaust at very lean mixtures, such as carbon monoxide, hydrocarbon, and NOx emissions. Exhaust temperature of RMG engine was lower than gasoline engine under the same conditions, about 70～90℃at engine speed of 1800r/min. The peak cylinder pressure of RMG engine was higher than that of gasoline engine. The location of peak pressure of RMG engine was earlier, and the pressure increasing rate was higher. Ignition timing had great effect on power, fuel economy and emission characteristics. With the advance of ignition timing, the load and thermal efficiency increased firstly and then decreased, the exhaust temperature decreased gradually, and the three regulated emissions (CO, HC and NOx) increased obviously. The reforming rate of methanol increased as the temperature of the engine-reformer system increased.