A plasma-catalyst hybrid converter operating under atmospheric pressure was developed and a series of experiments were carried out to investigate its hydrogen-rich gas production performance. The hydrocarbon fuel used was propane. In the converter, electrons were energized by an electric field to ionize the propane and air mixture. In addition, a catalyst was installed at the downstream of the reformer to enhance the production of hydrogen-rich gas. Firstly, a parametric study of the operating parameters was carried out to assess the reforming performance of the plasma-catalyst hybrid converter on producing hydrogen-rich gas. This was followed by a feasibility assessment with an engine supplemented by the hydrogen-rich gas produced by the hybrid converter. The ratio of combustion assisting and combustion impeding (A/I) composition was analyzed. It is anticipated that the results would serve as a good guideline for setting-up parameters when reforming hydrocarbon fuels onboard vehicles. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.