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What will the passenger car fleet look like over the next two decades' As most expected, affordability and convenience are the major drivers of new vehicle technology penetration into the market. Within this scope, vehicle electrification strategy to limit oil dependence and meet the European targets for CO₂ emissions should be cost-effective and convenient to the buyer. This paper will focus first, through different economic models, on the penetration of passenger electrified vehicles (Plug-in Hybrid Vehicles PHVs and Electric Vehicles EVs) in Europe (EU15: 15 European Union member countries) up to 2030. Economic models are based on real-world-use behaviors and driving patterns in order to compute fuel and energy consumption and to estimate total cost of the vehicle including incentives. The economic models use household wages in order to later make conclusions on vehicle technology market shares by vehicle classes.

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.

The B-COOL project, funded by the European Union, is devoted to the development of low cost and efficient R-744 system for small cars. In the framework of this initiative a Fiat Panda and a Ford Ka prototype have been realized adopting two different R-744 systems and a testing procedure has been identified and adopted to qualify the vehicles in terms of fuel consumption and thermal comfort performance. The Project started in March 2005 and ended in November 2008, this paper presents the major project outcomes on R-744 mobile air conditioning systems (efficiency and related fuel consumption and LCCP, costs, architecture) synthesizing the remaining technology open issues

The EU Commission has decided to establish a regulatory type test approval method for the guarantee of initial leak tightness of R-134a MAC systems in Europe. This method of test will be applicable as of July 2007. In order to establish the method of test the European Association of Car Manufacturers (ACEA) has launched a study for the development of a technically-sound method. The Center for Energy and Processes has carried out the study at three levels: a fleet tests of 40 vehicles, laboratory tests on 40 MAC systems identical to the ones installed on the fleet cars, and tests of 160 components. The paper describes the charge and recovery method in order to guarantee a precision of recovery of 0/-1 g for the fleet of vehicles. Results of the fleet tests show that the average emission level is of 10 g/yr. The paper describes also the laboratory method of test based on the measurement of the R-134a concentration inside mini-sheds using infrared techniques.

The components of mobile air conditioning (MAC) systems follow different emission laws. Hoses are typically following a diffusion law that needs to identify solubility coefficient, permeability coefficient, and dependence on the temperature. Shaft seal, fittings, valves show different behaviors dominated by viscous law, the diffusion representing a limited part of emissions. Two hundred development tests carried out on those different components are used to elaborate behavior laws for hoses and hose materials, the effect of clearances for fittings is also studied. The paper concludes at what conditions it is possible to elaborate a generic approach allowing to limit the number of measurements.

This paper presents an experimental investigation of two passive thermal preconditioning technologies, pre-ventilation and solar shields, and a combination of both. A Design of Experiment (DOE) was defined in order to evaluate the influence of several parameters (air mass flow and air diffusion mode, size of the air extractors, location and type of solar shield) on the passengers' thermal comfort on entry into the car cabin and after a short A/C running time (10 min). Results show that solar shields are more efficient than pre-ventilation, which means that radiative heat transfers are more effective than the convective heat transfers, even with high air flows. The type of solar shields together with their location on the windows is also influential. After preconditioning, 10 minutes of air conditioning might reduce the air temperature at face level of the front passengers, compared to a non preconditioned car cabin.

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.

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%.

Due to the global warming effect of R-134a emissions, regulations will be issued to lower the current emission level of Mobil Air Conditioning (MAC) systems. In order to develop very low emission components, it is necessary to have accurate measurement apparatus both for components and for the complete AC system. The paper presents the method of test, the testing equipment, and the test results of several AC systems installed in a “mini-shed”, which is at atmospheric pressure, completely tight and where the raise of concentration of R-134a is measured by infra red spectrophotometry. The tests are performed in standstill mode for different temperatures. The results are the emissions as a function of the saturating R-134a pressure for different temperatures. A new evolution of the test bench is being prepared in order to measure emissions when the MAC system is running along different driving and temperature conditions.

External Control Compressors (ECC) with variable displacement are available on the market and permit to create smart control system, taking into account both cooling needs of the cabin and the engine running speed. With a limited number of sensors it is possible to create new algorithms to control the refrigerant mass flow rate. The paper presents a reference line of a mobile air-conditioning system using a variable displacement compressor and the improvement associated with the new control system. The tests have been performed according to the European regulatory reference cycle in order to measure fuel consumption of vehicles taking into account both urban and extra-urban cycles. It is essential to analyze mobile air-conditioning systems energy performances, referred to realistic conditions taking into account the quick variations of engine speed during various driving cycles.

This paper presents the results of a study of the various thermal interactions between the automotive passenger compartment and the passengers, using the equivalent temperature concept. Radiative and convective heat exchanges are described. A technical proposal to improve the thermal comfort of passengers is also made.

The Centre for Energy Studies, with a financial support by ADEME (French Agency for Environment and Energy Management), has realized a test bench for the measurement of R-134a leak flow rates of Mobile Air-Conditioning) MAC components. The test bench is equiped with an infrared spectrophotometer permitting thorough and fast measurements. The measurement principle is simple. R-134a pressure is generated in gas phase in the component to be tested (in the study, the compressor). This component is located in a leak tight control volume at atmospheric pressure. The control volume is filled in recomposed air as to prevent any external pollution. The control volume is swept by a continuous flow permitting continuous measurement of the R-134a concentration in the measurement cell. Knowing the concentration increase, the control volume and the time, the concentration measure permits the calculation of the leak flow rate.

The purpose of the work is the representation of heat transfers in an automotive car cabin by a geometrical and physical simplified model. This one is represented by plane elements receiving a variable solar flux in direction and intensity. The significant heat transfers (conduction, convection, mass transfer and radiation) are taken into account. The aeraulic phenomena are represented by a zonal approach based on the volume split up in small volumes. Calculation estimates in parallel the view and transfer factors, as well as internal and external solar flux density. Results are surface temperatures of the car cabin, in-vehicle air temperature at different levels and also heating or cooling capacity to reach an acceptable comfort level. Experiments have been performed for the validation of calculations. In this paper, validation of the natural convection heat transfer is only described. Results are in good agreement with the experiment.

During summertime, some in-vehicle components can reach very high temperatures, in particular because of solar radiation through windows. The liquid-filled double glazing (LFDGW) window permit the solar gain because of its absorbing properties and consequently permit to maintain the window temperature. The impact of such a window on in-vehicle temperatures is evaluated with the Therm_Cab® software. Results indicate that the temperatures of the in-vehicle component are reduced significantly.