The practical implementation of methanol as a clean and efficient alternative fuel for automotive vehicles

Ever since the energy crises in 1970s, the methanol, among other alternative fuels, has been studied for automotive application. The methanol has been widely used for auto racing due to its superior anti-knock characteristics. However, aldehyde is a highly toxic pollutant and aldehyde emission out of alcohol fuel combustion could be considerably higher than spark-ignited gasoline engines. The corrosion and durability of methanol fuel components were also concerns for mass production of methanol-fueled vehicles. The authors have worked with an automotive manufacturer in China to investigate the brake thermal and emission improvement potentials of a methanol-fueled, spark-ignited engine over the original gasoline engine on a passenger car application and to demonstrate the performance and China V emission compliance over its useful life of 160,000 km. The study found that the methanol-fueled engine has 4%-6% brake thermal advantage over the original gasoline engine, and a three-way oxidation catalyst has successfully managed the tailpipe emissions under China V emission limit, consistently over the journey of 160,000 km. The test data show that the tailpipe aldehyde emission is actually reduced to a level that is below what is required by US LEV III emission standard, largely due to the three-way oxidation catalyst and the gasoline cold start assistance at the beginning of the transient emission cycle. This study indicates that methanol-fueled engine might be an attractive low-cost alternative for a more efficient and clean powertrain over conventional gasoline when a light-duty diesel engine faces challenges from future China VI emission regulations.