A new field problem associated with flakes of combustion chamber deposit (CCD) getting trapped on the exhaust valve seat has been reported by several car manufacturers in Europe. This causes difficulties in start-up and poor driveability. A road test procedure that is reasonably quick and sensitive to fuel changes has been developed to study the deposit flaking problem. The flaking of the deposits is believed to be caused by water - either generated by combustion or existing in the ambient air as water vapour - condensing on the deposits. Water is much more effective than fuel in causing deposit flaking. A way of quantifying the deposit flaking tendency has been defined and its repeatability established based on twenty-nine tests using two different cars and different fuels and additives. There are large differences between base fuels in terms of CCD flaking. Deposit flaking tendency is reduced by running the car in a higher duty cycle or by using conventional detergent additive packages particularly at higher dose rates. The extent of such an effect of additives also depends on the base fuel. The same test methodology was also used to study two different car models by another manufacturer that differed significantly in terms of the field problems associated with deposit flaking; it was found that the test results agreed with the field experience.


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    Title :

    Combustion Chamber Deposit Flaking Studies Using a Road Test Procedure


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    SAE Powertrain & Fluid Systems Conference & Exhibition ; 2002



    Publication date :

    2002-10-21




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Combustion Chamber Deposit Flaking - Studies Using a Road Test Procedure

    Kalghatgi, G. T. / Society of Automotive Engineers | British Library Conference Proceedings | 2002


    Combustion chamber deposits flaking - studies using a road test procedure

    Kalghatgi,G.T. / Shell Global Solutions,GB | Automotive engineering | 2002


    Combustion Chamber Deposit Flaking

    Kalghatgi, G. T. / Price, R. J. / Society of Automotive Engineers | British Library Conference Proceedings | 2000


    Combustion Chamber Deposit Flaking

    Kalghatgi, G. T. / Price, R. J. | SAE Technical Papers | 2000


    Combustion chamber deposit flaking

    Kalghatgi,G.T. / Price,R.J. / Shell Global Solutions,GB | Automotive engineering | 2000