8
Figure 5. Concentrations of criteria gases: (a) CO, (b) NO
2 ,
and (c) NO. The error bars represent one standard deviation
of mean. The results for Engine 3 and Engine 4 were adopted
from a previous publication [39]
Figure 6. Dependance of NOx emissions and the NO
2 /
NOx relationship on exhaust temperature at the inlet
to the exhaust aftertreatment devices for: (a) Engine 1,
(b) Engine 2, and (c) Engine 3