Experimental Investigation on the Emissions of a Port Fuel Injection Spark Ignition Engine Fueled with Methanol-Gasoline Blends

摘要

The prospect of using methanol as an alternative fuel for vehicles in China is enticing because of its good combustion properties, low production cost, and renewable capacity, but the in-cylinder combustion of methanol also brings extra emissions concerns, such as alcohols and aldehydes. For the impact of methanol gasoline blends on the pollutant emissions of spark ignition (SI) engines to be investigated, a GEELY MR479Q port fuel injection SI engine was selected for tests of burning different methanol gasoline blends at wide-open throttle operating conditions, and an AVL Fourier-transform infrared multicomponent gas analyzer was used to measure all of the emissions. Test results show that the methanol-containing fuel blends had positive effects on the engine-out regulated emissions. Nitrogen oxide, carbon monoxide, and nonmethane hydrocarbon emissions were all dramatically reduced when the test engine was fueled with methanol gasoline blends. Other hydrocarbon emissions such as ethylene, propylene, and soot precursors like acetylene and aromatic hydrocarbons were also reduced with the methanol gasoline blends. However, the methanol in the fuel blends caused significant elevation of engine-out unburned methanol (CH3OH) and formaldehyde (CH2O) emissions at the same time, especially for high methanol-containing fuel blends, such as M50 and M70. When fueled with M70, engine-out unburned CH3OH emission could reach as high as 500 ppm, and CH2O emission was almost 4 times as much as that of MO. Other emissions like ethanol, acetaldehyde, and 1,3-butadiene were observed to be only slightly influenced by methanol during the engine tests.