
Originally Posted by
Homestar
Yeah - smoke and mirrors sound right - but by which side? I’d be interested in the comparison between a modern petrol burning engine and a modern diesel with adblue - I honestly don’t know which would come out on top overall.
I suspect a lot of the confusion comes from what is considered "emissions". From a climate change point of view, for any internal combustion engine, almost all the carbon atoms in the fuel enter the atmosphere as carbon dioxide, whether we are talking about petrol or diesel. A larger proportion of the diesel is carbon than is the case for petrol, so for the same mass of fuel burnt, more carbon dioxide is emitted by a diesel. But the diesel will usually use less fuel than the petrol, everything else being equal.
The other type of emissions are those that are not carbon dioxide and water - these are unburnt or partly burnt fuel and oil and nitrogen oxides. In modern petrol and diesel engines these are very small, but vary much more between designs. The adblue is intended to deal with the nitrogen oxides, that tend to increase as combustion temperature is increased - which is what is needed to reduce unburnt and partly burnt fuel, as welll as to increase efficiency.
John
JDNSW
1986 110 County 3.9 diesel
1970 2a 109 2.25 petrol
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