How Audi cheated emissions tests: if (steering) then (pollute)


Originally published at:

Man blocks car exhaust

VAG seems to have gone massively downhill. But I am unsurprised.
Back on around 2007 when there was a lot of talk of clean diesel, Toyota engineers said that the reason they had gone for hybrid was because they did not believe diesel could be cleaned up enough to meet future emissions. Despite having started my career in Diesel R&D, by then I was getting worried about particulates, and my next car was a Prius, the first non-Diesel I had in many years. The Prius wasn't satisfactory for various non-powertrain related reasons, but I still have two gasoline Toyotas.
I have always respected Toyota and Honda engineering, and if they thought it wasn't really possible they had to be listened to. I suspect that the Germans got all excited about adding urea and then found out just how much would be needed - I would not be surprised if some of their urea-additive cars stop adding the urea outside test mode.
Recent spark ignition engines have been getting competitive with Diesel on carbon emissions, and I don't expect them to die out soon. But I do expect gathering pressure to get rid of Diesel vehicles. The future may be LNG or even hydrogen, but currently EVs are not going to work at significant scale unless batteries can get off lithium and perhaps onto an aluminium based technology.
The Germans seem to have backed themselves into a corner, depending on Diesel as a differentiating technology and with very expensive and complicated spark ignition engines to get enough power with low emissions in the US market. The future is going to be technically interesting but I suspect VAG may not be as big a player in it.


I'm an Audi driver, on a lease that's due for renewal next year. Looks like my next car will be a BMW.


If (steering) then (pollute) is a pretty elegant algorithm for checking for emissions testing.



I wonder how long the engineers have been holding their breaths waiting for this to be discovered after the initial Dieselgate findings?


Are you sure they weren't just holding their breaths because of the extra pollution?


And VW is still allowed to sell cars in the USA because why?


It's not 'holding your breath', it's 'test mode respiration'. VW engineers switch over to anaerobic metabolism when they detect test conditions; then revert to aerobic metabolism in the field.


It's the fuel rather than the manufacturer that is the issue.


Wanna bet this applies to all vehicles made by the VW Group? Why would Audi keep this to itself and not share it with the whole family? Who's to say it even originated with Audi?


If you're telling me I shouldn't have a (modern, efficient) car (that I use only at weekends and cover about 3000 miles a year in), then you're perhaps correct in principle but entirely unrealistic.

If the message is something else, then could you explain it?

EDIT I get it, sorry. My car is not a diesel; I just don't like buying from unprincipled companies, and VW have been caught twice so they're out.


Not the A4, not the A4... Whew. Safe until the next round of disclosures, at least.


The "pollution" issue is interesting.
The original rush for Diesel was because it gives very good mid range torque and low carbon dioxide emissions. But the high CR also leads to the nitrogen in the air reacting with the oxygen to form nitrogen oxides, a particular problem with Diesels too because there is always excess oxygen present.
As well as the NOx, there is the particulate problem. Old non-turbo Diesels produce a lot of soot. In areas of high rainfall soot and NOx aren't actually too bad - they end up in the soil and the NOx is a fertiliser. But improvements in combustion made the carbon particles ever smaller so, paradoxically, they stay around in the atmosphere longer - and are more dangerous because they penetrate further into lungs. Being smaller, they are also harder to filter out and particle filters themselves have significant problems.
So the seriousness of Diesel pollution is very much a factor of things like the local climate and population density. In the rainshadow of the English Lake District with 2M of rain a year, Diesel isn't a problem. In the centre of Bath - or for that matter LA - with lower rainfall and less wind, it's a serious issue. Globally, carbon dioxide emission is the real problem; the obvious answer to this is smaller cars but the US public won't buy them, partly because of bad roads.

What I am trying to say is that VAG have been trapped by a very large systems problem which has paradoxical rewards for bad behaviour. It may well turn out that other Diesel car makers like BMW or Daimler are actually having the same issues, because they face the same system challenges, it's just that they didn't make the same rush for Diesel in the US.

In an ideal world I guess we would assign a "pollution factor" to a vehicle depending on where it was going to be used, and tax accordingly.


i was always hoping for more hybrid bio-diesel solutions. I had an old Audi diesel imported from Europe that got 46mpg which is crazy, the thing had no power, but damn it sipped on the fuel, nothing like it on the north American market at the time. When you couple a small diesel engine designed to be as clean as possible with an electric system the results are pretty good.

I really like some of the new all electric cars, and likely my next car will be one, but i also worry that batteries aren’t as clean as we like to think. we don’t have much transparency about the impact of batteries.


I'm not telling you to do anything, I'm just commenting on technology.


Problem is, bio-Diesel is just as dirty as low sulfur fossil oil, and depending on source may be worse for particulates.
If there is a god of this world, she's telling us "hydrogen, methane and propane, these have I given you to power your combustion engines. But you did not hearken unto me, and now you have big pollution problems"


i was hoping for some improvements in that area as well. it does have the carbon neutral thing going for it. in small engines, like in a hybrid system, the ability to clean the output is much greater. i get it isn’t perfect, but it can be done in a way that it is a viable contender.

I like hydrogen, but we have yet to “crack” it in a way that is great. The energy to produce is very high, and unless we use green energy we are just shifting the point of pollution, also it is a but tricky to store enough in a vehicle in a safe way. maybe hydrogen-electric hybrids will help push that forward?


Batteries don't worry me too much (except in terms of scale - if everybody went electric charging stations would need to be much more common than present gas stations and the entire electricity supply system would need overhauling in towns and along major routes.)
The issue is how the electricity is generated. If it is from coal plants, your electric vehicle is worse than a modern gasoline engine. If it is from oil, allowing for transfer, charge and discharge losses it may be no improvement. If it is wind, solar or nuclear, then battery vehicles have a point.
If you do a lot of short journeys, then the payback for battery is better because of the increased emissions while the IC engine warms up, but you may never do the miles to pay for the battery energetically.
Everybody has their own needs and there is no one size fits all. Living where we do, we have a small town car and a larger MPV (still small in US terms) which, since they are reasonably state of the art, I intend to keep for a while. It will probably take 15 years to hit the 100K mark on both of them.


I know that here in the NW there are times where the dam operators must spill water and produce power, i.e. when the basins are overfull, or when fish need it. At those times the dams pay the wind farms not to produce power, since it is more than the grid can hold. I've often thought that the wind farms could become hydrogen factories during those, or other times, when it makes economic sense. Assuming there is sufficient water available to do so. I think it would work, at least for a localized hydrogen economy.


You seem to understand this - can you help me? I don't understand the CO2 as pollutant thing. Isn't the whole idea of catalytic converters and ever greater engine efficiency to ensure the only outputs of combustion are CO2 and water?

How do you generate low CO2 output? Is this just about greater fuel efficiency?