Apostolos PESİRİDİS, Alasdair CAİRNS, Matt BARBER

Comparison of Variable ValveStrategies at Part Load for Throttled andUn - Throttled SI Engine Configurations

The presented work concerns the study of the fuel consumption and emissions benefits achieved at part load by employing a fully variable valve train in a 1.6L SI gasoline engine. The benefits achieved when using variable valve timing alone, and combined with an early intake closing strategy for un-throttled operation were explored in order to highlight the merits of throttle versus un-throttled engine operation in conjunction with variable valve timing and lift. In addition, particular interest was given to the presence of internal Exhaust Gas Recirculation (EGR) and its ability to reduce pumping loss at part load. An engine model employing multiple sub models to handle variable valve operation was constructed using a commercial gas dynamics engine code, allowing detailed analysis of three valve strategies. Using the engine model, a theoretical study validated by experimentally available data was carried out to study key valve timing cases. A detailed breakdown of the mechanisms present in each case allowed a comprehensive understanding of the influence of valve timing on gas exchange efficiency and fuel consumption

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International Journal of Automotive Engineering and Technologies-Cover

Başlangıç: 2012
Yayıncı: Murat CİNİVİZ

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