Engine performance and emissions formation for RME and conventional diesel oil: a comparative study
Paper in proceedings, 2009
A comparative study on engine performance and
emissions (NOx, soot) formation has been carried out for the
Volvo D12C diesel engine fueled by Rapeseed Methyl Ester,
RME and conventional diesel oil. The combustion models,
used in this paper, are the modifications of those described in
[1-2]. After the compilation of liquid properties of RME
specified as methyl oleate, C19H36O2, making up 60% of RME.
The oxidation mechanism has been compiled based on methyl
butanoate ester, mb, C5H10O2 oxidation model 
supplemented by the sub-mechanisms for two proposed fuel
constituent components, methyl decanoate, md, C11H22O2, nheptane,
C7H16, and soot and NOx formations reduced and
“tuned” by using the sensitivity analysis. A special global
reaction was introduced to “crack” the main fuel into
constituent components, md, mb and propyne, C3H4, to
reproduce accurately the proposed RME chemical formula.
The sub-mechanisms were collected in the general one
consisting of 99 species participating in 411 reactions. The
combustion mechanism was validated using shock-tube
ignition-delay data at diesel engine conditions and flame
propagation speeds at atmospheric conditions.
The engine simulations were carried out for Volvo D12C
engine fueled both RME and conventional diesel oil. The
numerical results illustrate that in the case of RME, nearly
100% combustion efficiency was predicted when the
cumulative heat release, was compared with the RME LHV,
37.2 kJ/g.. To minimize NOx emissions, the effects of 20-30%
EGR levels depending on the engine loads and different
injection strategies were analyses. To confirm the optimal
engine operation conditions, a special technique based on the time-transient parametric j-T maps has been used.