Driving cycle simulation of a vehicle motored by a SI engine fueled with H₂-enriched gasoline

In the present study, the effect of the amount of hydrogen supplement to a gasoline engine is theoretically investigated in terms of the vehicle performance running over a standard driving cycle. A rigorous mathematical model which considers the vehicle dynamics, transmission losses, the gas exchange and combustion processes inside the cylinder, as well as the chemical kinetics of the formation of the relevant products has been developed. The model was employed to predict the fuel consumption, engine power and the emission level of CO, HC, CO₂ and NO_x over the European ECE-15 and Japanese 10-mode driving cycles. Based on a previous work of the present authors, the hydrogen was considered to be produced by an on-board on-line auxiliary generator, which consumes a mixture of gasoline and water. It has been shown that a significant reduction in the total fuel consumption in the order of 15 to 20% and an associated reduction in HC, CO and NO_x emission levels, is achieved with only 6% of hydrogen enrichment (hydrogen to fuel mass ratio).