E-Fuels for passenger cars: An analysis with GT-SUITE to investigate fuel efficiency and air pollutants

Abstract

This study analyses a range of E-Fuels and their potential to reduce CO2 emission, fuel consumption and air pollution of passenger cars. The study investigates drop-in fuels used in cars representing today's vehicle technology as well as new fuels in drivetrains that are optimised for their use. The analysis is undertaken using GT-SUITE, combined with the plug-in UserCylinder. Firstly, it investigates the drop-in fuels M15 (15% methanol, 85% gasoline) and a blend of 50% hydrogen and methan (HCNG). The performance of M15 in terms of fuel efficiency and air pollution is compared with conventional gasoline (E5), while HCNG is compared to the conventional counterpart, natural gas (CNG). Secondly, the study investigates the optimization space of combustion engine using methanol as pure fuel (M100) and compares its performance with conventional gasoline (E5) in a todays car. In the case of M100, the compression ratio of the gasoline engine was increased to 14,5:1, up to the knocking effect at the full load. Fuel consumption and emissions using the Worldwide harmonized Light Duty Test Cycle (WLTC) are determined on the basis of consumption and engine-out emission maps. The results show that tank-to-wheel CO2 emissions of HCNG and M100 are lower compared to their reference cases (E5 and CNG). No significant CO2 benefits were identified for M15. Nitric oxide (NOx) raw emissions are higher using M15 and HCNG compared to the reference case, while the use of M100 led to lower emissions. Carbon monoxide (CO) raw emissions can be reduced with M15, HCNG and most substantially with M100. This study considers raw emissions based on using three-way catalytic converters at operating temperature. A comparison with measured operating emissions from other studies shows that, particularly for M15 and M100, challenges can arise during cold starts with regard to the operating temperature of the three-way catalytic converter.