Troels Dyhr Pedersen.indd - Solid Mechanics
Troels Dyhr Pedersen.indd - Solid Mechanics
Troels Dyhr Pedersen.indd - Solid Mechanics
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Page 17 of 22<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0.0<br />
1000 RPM, MEOH 1800 RPM, MEOH<br />
1000 RPM, EGR 1800 RPM, EGR<br />
NOx [g/kWh]<br />
Engine power [kW]<br />
0 10 20 30<br />
Figure 14: Specific NOx emissions during testing<br />
The instrument does however not allow for separate determination of NO and NO2. The majority of nitric oxide<br />
is therefore considered to be NO. Specific emissions are therefore calculated from a molar mass of 30 g/mol.<br />
The DOC is known to convert NO to NO2 to some degree, depending on the catalyst temperature. Since NO2 is<br />
generally considered more harmful than NO, it may be argued that using a DOC to convert HC and CO is<br />
having a negative side-effect by forming NO2. With HCCI combustion this negative effect is however<br />
negligible given the very low NO concentration compared to HC and CO levels.<br />
THC<br />
The specific emissions of THC before the DOC are plotted in figure 15. Methane concentrations before the<br />
DOC made up 10-20 % of the THC, which is possibly due to the lack of post-oxidation and the fact that<br />
methane is a stabile molecule.
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