Internal combustion engines water injection fed by Exhaust Water Recirculation (EWR): a feasibility analysis

Water injection is one of the ways available to mitigate internal combustion engine propelled vehicles pollutions. Its practical use, yet, may require the presence of an additional liquid water tank on board, which implies new costs and constraints. In the present paper, we try to figure out whether such a tank is really needed or not. Ambient humidity, fuel chemical composition, Water–Fuel Ratio and water recycling effectiveness are combined into a water balance model of concerned engines. The obtained results are really encouraging: considering the effectivenesses of existing water recycling membranes, almost all water needs of water injection can be satisfied, without any water tank, and for most of liquid and gaseous fuels. The Exhaust Water Recirculation system presented in this paper is, thus, probably one of the key components water injection will need to be used more widely on future vehicles.