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Energy consumption and exhaust emissions are the most challenging issues in transportation that car makers and policy makers have to deal with. As a consequence, several technologies have been developed in order to limit fuel consumption and pollutant emissions. So far, some of the promising technologies for passenger cars are hybrid electric vehicles (HEV) and, later on, plug-in hybrid electric vehicles (PHEV). The study presents an assessment in terms of energy consumption and carbon dioxide emissions for gasoline HEV and PHEV compared to Internal Combustion Engine (ICE) conventional gasoline and diesel vehicles. This comparison intends to assess carbon dioxide and energy consumption reduction ability of PHEV for several countries or geographical region (EU 15, USA, Japan, and France). The energy consumption is computed with a detailed drive train model taking into account different driving patterns.

Electric hybrid vehicles change the global design of the electrical power on board, but also of the thermal engine. The concept presented is based on recovery and conversion of thermal energy from the engine cooling circuit and the exhaust pipe by a Rankine cycle. The paper presents the choices of thermodynamic fluids permitting to reach appropriate energy efficiency for conversion of heat in electricity. Water, R-245ca, isopentane are compared and different technical options are studied. Potential for improving the net fuel consumption of hybrid vehicles is estimated to be as high as 32%.

The new Prius hybrid vehicle uses an electrical scroll compressor which speed is controlled by an inverter. The control is integrated in the vehicle global control system. The paper presents the way to take into account the state of charge (SOC) of the batteries to run reproducible tests and in order that the battery charge is identical both at the end and at the beginning of the test. The vehicle fuel consumption has been analyzed with and without the air conditioning (AC) system running and for two different climatic conditions. Moreover tests have been carried out for the measurement of the electrical consumption of the AC system. Conclusions are drawn on the interest of electrical AC system compared to mechanical AC system for hybrid vehicles. The impact of the control system is also analysed and presented.