Exhaust Emissions from a Methanol-Fueled Automobile 720693

An American Motors Gremlin has been converted to low-pollution operation on methanol through the use of an exhaust-heated intake manifold, a rejetted carburetor with heat exchanger for heating of fuel-air charge, a catalytic muffler, and an exhaust-port air injector. Tests carried out at EPA laboratories demonstrated that this car surpasses the 1975-1976 federal standards for unburned HC, CO, and NO_x. The low levels of HC and CO are due to lean operation and the use of an oxidizing catalyst. The low NO_x emissions are due partially to retarded spark-timing and lean operation, and, as indicated in a chemical kinetic model of NO formation, to properties of methanol that are favorable to low NO levels. Results of gas chromatograph and chemical analyses of the exhaust for organics, aldehydes, and ammonia are also discussed.