A variable compression ratio can help to resolve the conflict between part load and full load CR layout especially at boosted downsized gasoline engines. Depending on the VCR (variable compression ratio) concept and engine downsizing grade, the cycle simulations for NEDC (new european driving cycle) and WLTP (worldwide harmonized light vehicles test procedures) predict a fuel benefit between 5.2 and 7.2 % for the chosen vehicle and powertrain configurations. The three different types of VCR concepts have different impact on the engine architecture. Therefore, some systems can only be implemented in a new engine family while others can be applied as a derivate of an existing engine. The direct comparison of these systems shows, that there are conflicting demands of benefits and costs. The maximum thermodynamic potential of VCR can only be accomplished with continuous VCR systems but goes along with relatively high additional costs. The 2-stage VCR shows a fuel benefit decreased by 0.7 to 1.4 %, but still offers a better cost/benefit ratio compared to the continuous system. Therefore, the 2-stage VCR system seems to be a good compromise, especially for retrofitting into existing engine architectures.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    The conflicting demands of thermodynamic benefits and costs for a variable compression ratio


    Additional title:

    Die variable Verdichtung im Spannungsfeld zwischen thermodynamischem Potenzial und Kosten


    Contributors:


    Publication date :

    2012


    Size :

    18 Seiten, 21 Bilder, 4 Quellen


    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    The conflicting demands of thermodynamic benefits and costs for a variable compression ratio

    Wittek,K. / FEV Motorentechnik,Aachen,DE | Automotive engineering | 2012


    Southampton water -- Conflicting demands

    Pannell, J.P.M. | Engineering Index Backfile | 1964


    Conflicting demands in the driving task

    Lansdown, T. C. | British Library Conference Proceedings | 2001


    Benefits and challenges of variable compression ratio ( VCR )

    Roberts,M. / Prodrive,GB | Automotive engineering | 2003


    Benefits and Challenges of Variable Compression Ratio (VCR)

    Roberts, Martyn | SAE Technical Papers | 2003