Thermo-Chemical Recuperation as an Efficient Way of Engine's Waste Heat Recovery

Abstract

It is known that about 30% of fuel energy introduced to an internal combustion engine (ICE) is wasted with engine exhaust gases. One of the promising ways of waste heat recovery is thermo-chemical recuperation (TCR). For the purpose of TCR realization, in principle any fuel may be used. However, utilization of renewable bio-alcohols, especially ethanol or methanol is the most favorable. The advantages of TCR over turbocharging are in the fact that its energy transfer is not limited by isentropic expansion and that the reforming process improves the fuel properties. A comprehensive theoretical analysis of the ICE with TCR was carried out using the developed model for simulation of the joint operation of ICE with alcohol reformer, when the ICE is fed by the alcohol reforming products and the energy of the exhaust gases is utilized to sustain endothermic reforming reactions. Simulation results show that it is possible to sustain endothermic reforming reactions with a reasonable reactor size. Modeling results point out a possibility of engine's efficiency improvement by up to 13% in comparison with ICE feeding by gasoline together with achievement of zero-impact pollutant emissions.