Experimental investigation on exhaust emissions of a heavy-duty vehicle powered by a methanol-fuelled spark ignition engine under world Harmonized Transient Cycle and actual on-road driving conditions

Abstract

Compared to the conventional fossil fuels, methanol is a renewable, environment-friendly, and inexpensive oxygenated fuel. In this work, to explore the feasibility of using methanol as a substitute for diesel or gasoline in internal combustion engines, the exhaust emissions of a heavy-duty vehicle powered by the methanol spark ignition (SI) engine are tested under the World Harmonized Transient Cycle (WHTC) and actual on-road driving conditions. The results indicate that the brake specific CO, NOx, PM, and non-methane hydrocarbon emissions of the heavy-duty engine fuelled with methanol under the WHTC are lower than those of the engine fuelled with diesel and diesel-gasoline. However, the NH3 emission of the heavy-duty engine fuelled with natural gas is much higher than that of the methanol-fuelled engine, and exceeds the China VI emission standard. Under the actual road test, CO emission decreases once the exhaust temperature of the test vehicle reaches up to 250 °C, while NOx emissions are maintained at a relatively low level and then sharply increase at the initial cold-start of the road test. However, NOx emissions increase with further increase in the exhaust temperature.