Study on gasoline on-board exhaust gas reforming system for hydrogen production in vehicle

Abstract

This dissertation deals with gasoline on-board exhaust gas fuel reforming to produce hydrogen in vehicle system. The automotive industry faces problems with regard to its consumption of fossil fuel and pollutants emissions. In current manner, hydrogen in vehicle is presented for the improvement of current vehicle system. Therefore, we must find a stable and continuous method for supplying hydrogen to the vehicle. In this dissertation, validation of the possibility of exhaust gas fuel reforming and elementary studies for vehicle application were investigated. Thermodynamic equilibrium calculations were validated the appropriate on-board fuel reforming oxidant. According to results, lean burn exhaust gas was suitable for on-board fuel reforming system. To confirm the suitable operating condition, catalytic reforming experiments were investigated. Elementary tests using iso-octane were investigated with Pt/CGO (0.5 wt. %). Exhaust gas with high oxygen concentration was produced less hydrogen. In commercial gasoline test, highest hydrogen production was obtained at the exhaust gas ratio of 2~3% at the fuel ratio of 5%. However, degradation occurred when under 700$\circ C$ and lack of oxidant supply. To operate sustainable reforming system, catalysts screening and applying fuel injector were investigated. Among Pt, Rh, Ru catalysts, Ru catalyst was activated until 600$\circ C$. Therefore, the Ru/CGO (0.5 wt. %) is suitable for on-board exhaust gas fuel reformer. In addition, application of fuel injector increased reforming performance at lower and higher exhaust gas ratio. Operation tests of exhaust gas gasoline reforming were investigated at various exhaust gas condition on 600oC with Ru/CGO. Generally, catalytic exhaust gas fuel reforming produced about 1.5~2.5% of hydrogen energy fraction of gasoline in engine. With addition of carbon monoxide in reformate, energy fraction increases about 3~5%. Also, with connection of the reformer to engine, hydrogen was produced similar to micro reactor operation and improved fuel economy by 1~2% in DBL condition.