This paper investigated the emissions performance of a passenger car powered by the hybrid hydrogen-gasoline engine under the New European Driving Cycle. The hydrogen was produced from an onboard water electrolysis hydrogen generator fixed in the trunk. The test results demonstrated that, when the engine was started with pure hydrogen for the first 7 s and fueled with the pure gasoline after 11 s from the onset of the cold start, CO and HC emissions were reduced by 62.1% and 64.1%, respectively. The vehicle emissions performance could be improved from the Euro-II emissions standard of the original vehicle to the Euro-IV emissions standard of the hybrid hydrogen-gasoline engine-powered vehicle. (c) 2013 Elsevier Ltd. All rights reserved.