Talk Morgan Forums Community Vehicle Talk (non-Morgan) Volkswagen to Recall Nearly 500,000 vehicles

I think the fact that VW had a specific program only for use when it detected test conditions is damning.
This is different to tuning engines to reduce emissions. Camshaft profiles, injection, oil viscosity, gearing, tyres, etc have all changed to produce low emission figures not always for the better.
Why does a remapped diesel produce a smoother, quicker and more economical engine?
It would probably fail the Californian emissions test.

Much of this is due to NOx emissions isn't it?, these are kept low for the test and then wind up the turbo & fueling etc for road use and the NOx increases. Car companies have been doing this for years, certainly some were in the 1990's to my first hand knowledge, just VW got caught. mmmmmmmm PJB.

The wording of the US test is a crucial thing here and the selection of cars used for testing. I bet car industry lawyers are combing the wording for chinks to use.
In Europe cars are tested randomly as they come off the production line but could still have smart software to detect test conditions....
As per mpg claims made by manufacturers...false figures as they are laboratory test results not "real world and " used as a comparison between manufacturers cars only" is the cop out phrase when complaints are made.
I wonder which other manufacturers are being investigated....US manufacturers?
US does seem to have a bias to home grown products and treatment of US companies v foreign.
So much for free trade.....

Sales of Remaps will increase.
An ill wind etc etc.

I have been talking to a boy who knows about these things at work......

There is quite a detailed and accurate view of what happened here:

http://jalopnik.com/your-guide-to-dieselgate-volkswagens-diesel-cheating-c-1731857018

It's all about urea......no doubt countless jokes will follow...

However many rival manufacturers have been very perplexed as to how VW managed to get their diesel engines to pass US emissions regulations WITHOUT using urea until very recently. Now we know!!!

Everything talks to everything else on modern vehicle electronics due to the wonder of CAN bus technology. So look for:

• No steering movement
• Driven wheels moving but not the other wheels
• I'm starting from cold
• etc etc etc

I must be on a rolling road...so let's trigger "low emissions mode".. In VW's case the resultant map would make the car very low performance in normal driving...

All the rivals use urea injection to lower emissions....however you could put more urea in than normal if you detect an "emissions test"... Urea is normally topped up at service only...I bet the wise legislators will now monitor urea flow during tests too..

Perhaps we have someone on here who can explain why there has not been a similar legislation to that governing the introduction of unleaded petrol. Surely if the urea was included in the fuel you buy at the pump the whole issue could be resolved.

In a different but related issue: I run a 10 year old diesel which does not have a fine particle filter. In Italy Q8 premium diesel produces visibly less black smoke on hard acceleration so I buy that whenever I can. If one company can produce a fuel that is clearly less polluting they all can.

I was unaware of this whole urea thing until this VW story broke.

Could I be making a fortune by connecting up the urinals in my pub to a tank & selling on the contents ? Should one pee in the tank of one's diesel car before taking it for it's MOT ?

If urea was stable in the combustion phase, then it could be added exactly as you say (or we could all pee in our tanks - although the urea concentration would only be about 10% of what is required).

Sadly, the urea has to be added downstream of combustion, as a fine spray in the exhaust gas, upstream of the fine catalyst. The addition of urea converts the nitrous oxides into ammonia which is then converted in the catalyst to yield mainly nitrogen and water.

Thanks Stuart. I had not realised that it was injected into the exhaust system.

Aren't engine maps a compromise anyway?
Manufacturers used to put in a " compromise" map to suit different markets etc.
I had a Focus turbo diesel that was available in 2 power outputs and from what I could find out it was simply two map variants with everything else the same.
How many people have had their car remapped by a competent mapper to fine tune it and take out the compromise settings?
Some people have switchable maps.
How about the various modes on some cars...Sport/Race/Normal etc how would they figure in emissions tests?
A complex scenario indeed.
With the VW case it is the deceit factor behind the map that is the killing aspect.