Unregulated emissions, such as methanol and formaldehyde, from the methanol-gasoline engine are one of the most serious concerns regarding the use of low-content methanol applications in conventional gasoline engines. Gasoline, M10 M15, M20, and M30 were used as fuels in a Port fuel injection (PFI) gasoline engine EQ491i without any modification. The load performances of the engine were tested on an engine test bench. A Fourier transform infrared (FTIR) spectrometer was used to measure the unregulated emissions before and after it conventional three-way catalyst. The test results showed that the low-content methanol-gasoline blended fuels had little influence oil the engine power output and energy consumption. The cylinder pressure and heat release rate showed no significant variation with the increase of the methanol content in the blended fuel. However, engine-out methanol and formaldehyde, as unregulated emissions, increased almost linearly with the methanol content in the fuel, while the ethanol and acetaldehyde emissions were little influenced by methanol addition, The conventional three-way catalyst had a high conversion efficiency for the unregulated emissions and ultimately reduced the regulated and Unregulated emissions from the methanol-gasoline engine to the same levels as those generated by a conventional gasoline engine.
