Community Research and Development Information Service - CORDIS

Environmentally friendly methane fuelled cars

The METHACAR project gives some fundamental answers to the questions which arise when using natural gas as a fuel for vehicles. Methane (compressed natural gas (CNG)) high environmental potential, provided that new solutions are adopted for feeding the gas to the engine and for after-treatment of exhaust gasses. Multi-point sequential gas injection systems directly derived from gasoline solutions were developed. Also, dedicated catalysts with high methane oxidation efficiency for effective treatment of exhaust gases were developed. These are needed if the most stringent emissions standards foreseen for the future have to be reached. Moreover, careful design by means of computer-aided engineering (CAE) has to be used when designing the exhaust system, otherwise during the critical light-off phase the temperatures will be unacceptably low. Close coupling of the catalyst and effective thermal insulation of the exhaust manifold have to be implemented in the design. If this is not possible, the adoption of a starter catalyst will bring the same results but the cost will be increased. It is hoped that EC-EUDC 2005 proposed standards may be reached, although deterioration of the efficiency of the after-treatment system needs to be verified by field test longer than those performed within this project. In order to get the maximum benefit from natural gas, dedicated cars have to considered since the higher compression ratio possible allows to reach lower fuel consumption (5/7 % if compared with gasoline on an energy basis); carbon dioxide emissions will also be reduced by 20/25 %. The gas composition has been shown to be a critical issue. Recent studies have shown that the presence of sulfur has to be considered extremely critical for the catalyst efficiency over time. Inerts (nitrogen, carbon dioxide) are often found with high percentage in some countries natural gas and this can affect performance and emissions. Hopefully, the evolution of European Community (EC) emissions standards should exclude methane from pollution calculation as it is currently accepted in the United States.

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Luigi CONTI
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