The present work is focused on the development of energy-efficient internal combustion engines with minimized CO, CO2, CH and NOx emissions. In frame of this concept, a method for hydrogen-rich gas generation onboard a vehicle and, in particular, its application as an additive to the engine fuel was suggested and tested experimentally. For practical realization of the method, the catalysts for hydrocarbon fuel reforming to synthesis gas were created, compact under-hood mounted synthesis gas generator was designed, and integrated ICE-synthesis gas generator control system was developed. The tests proved fuel economy in city cycle and considerable decrease of CO, CO2, CH and NOx emissions. The prospects of the technology for the development of energy-efficient environmentally benign engines are analyzed. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.