Intérêts et bénéfices du moteur à taux de compression variable
Document de 11 pages .pdf en Anglais.
Résumé et introduction
Potential benefits of Variable Compression Ratio (VCR) spark ignition engines are presented, based on an examination of the relationship between Compression Ratio, BMEP and spark advance at light load and full load. Alternative methods of implementing VCR are illustrated and critically examined. System control strategies are presented. Potential manufacturing constraints are identified and their influence on system configuration is examined. Fuel economy benefits attainable from other technologies such as cylinder deactivation, camless valve operation and GDI are shown to be inferior to the use of downsized boosted engines. VCR is identified as the key enabling technology of such downsized engines.
Worldwide pressure to reduce automotive fuel consumption and CO2 emissions is leading to the introduction of various new technologies for the gasoline engine as it fights for market share with the diesel. So far, variable compression ratio (VCR) engines have not reached the market, despite patents and experiments dating back over decades. VCR technology could provide the key to enable exceptional efficiency at light loads without loss of full load performance.
This paper will review the many embodiments of VCR, the implications for volume manufacture and the strategy for VCR implementation in order to produce the