Recovery of the heat generated by internal combustion engines and transformation of this into useful power (mechanical or electrical) represents a major opportunity for a drastic reduction in CO2 emissions and the possibility of achieving the EU target of 95gCO2/km for 2020. Transformation of heat into useful energy, according to the conversion efficiency of the technology adopted can promote a 10% to 27% reduction in CO2 emissions in the combined cycle. CRF is studying and developing heat conversion systems, based on various technologies, that can be integrated in the engine and vehicle systems. At the current state of the art, the most suitable, promising system is based on the Rankine thermal-dynamic cycle, able to guarantee an effective compromise between energy conversion efficiency, impact on engine/vehicle and costs. Feasibility and impact on the engine and vehicle were tested on the prototype constructed. Based on available components and derived from those used for automotive air conditioning systems, it produces electric energy, recovering exhaust fume heat via a closed expansion cycle. A maximum conversion efficiency of 5% was measured, equivalent to a 10% reduction in consumption and CO2  emissions.