Particulates, unregulated and regulated emissions and catalytic converter efficiency evaluation of methanol (M15) fuelled BS-VI compliant light-duty spark-ignition engine

Methanol adaptation in the transport sector is being encouraged worldwide. Methanol, a high-octane fuel, is emerging as a strong fuel candidate for powering spark-ignition (SI) engines and it can be indigenously produced from low-value agricultural biomass waste and high-ash coal. This study investigated particulates and unregulated and regulated emissions from M15 (15 % v/v methanol, 82 % v/v gasoline, 3 % v/v propanol) fueled Bharat Stage-VI (BS-VI) 2020 compliant light-duty SI engine equipped with a multipoint port fuel injection system and compared it with baseline gasoline fueled engine. The catalytic conversion efficiency for controlling regulated and unregulated emission species are also discussed for both test fuels. The experimental results showed a reduction in carbonaceous emissions from M15 fueled engine. Hydrocarbons (HC), carbon monoxide (CO) and particulate emissions reduced, while oxides of nitrogen (NOx) emissions were comparable to baseline gasolinefueled engine. The catalytic conversion of CO emission was higher for M15 but lower for HC and NOx emissions. Various unregulated trace emission components such as formaldehyde, acetaldehyde, methane, ethene and propene reduced with methanol addition to gasoline. Considerable reductions in benzene and toluene trace emissions were observed for M15, but methanol and ethane trace emissions were higher. The catalytic conversion of all unregulated trace emission components was comparable for both test fuels except alcohols, where M15 exhibited increased trace emission values. The study reflected that M15 could easily replace gasoline VI-compliant light-duty SI transportation engines. However, verification of all regulatory emission compliances, diagnostics and durability compliances need be ascertained before large-scale implemetation.