Mercedes-Benz targeting average diesel NOx of ~30mg/km in RDE Stage 2 tests by 2020

jck66

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I'm all for reducing emissions, as long as it doesn't make an overly-complicated car more complicated and provide more failure points...
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
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I'm all for reducing emissions, as long as it doesn't make an overly-complicated car more complicated and provide more failure points...
I was thinking about this after returning from driving 1000 miles in the last 2 days and while being kept up from having coffee too late last evening, in particular what kind of "measures" this technology involves. As I understand it, a core requirement is to keep exhaust temp within the catalytically active window for SCR, although companion technology would effectively extend the SCR active range down to as low as 60°C.
http://www.lboro.ac.uk/enterprise/acct/
http://www.greencarcongress.com/2017/05/20170531-acct.html

Assuming Bosch's is not the same or similar as Loughborough University's tech, I thought about those times during idle or when I'm coasting downhill for an extended period of time - exhaust temp is way below the catalytically active threshold and is composed of essentially pure air. In order to maintain some minimum EGT, the engine would need to be throttled at part load, which would eliminate the fuel efficiency advantage of Diesels over gassers, or the valvetrain completely deactivated during overrun, which is complex and costly (but not out of the realm of possibility since most automakers already have cylinder deactivation technology for gassers that can be easily moved over to Diesels).

Which is it, or is it something(s) else entirely? We'll have to see more details from Bosch.

What is rather exciting about this technology is the stated need for a "fast-response air system". This brings to mind more use of super quick spooling turbos, electric compressors and incidentally, this is the same language that is stated as a key enabling technology of Mazda's Skyactiv-X engine (which uses a form of Rootes supercharger and other pieces). It is exciting if these quick-spooling turbos/compressors go into production and can be retrofitted by us enthusiasts into earlier engines.
 
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