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

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 degrees 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.