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German report on VW diesel scandal finds large gap between lab and real-world NOx emissions for German automakers; 630K vehicles in voluntary recall

A German inquiry launched as a result of the Volkswagen diesel emission scandal has found that there is a large gap between homologated emissions values from lab testing and real-world driving results for all German manufacturers.

German Transport Minister Alexander Dobrindt, who presented the results of the inquiry on Friday, said that only Volkswagen had used a software defeat device that detected test cycles (Prüfzykluserkennung) and altered calibrations accordingly. However, other manufacturers do use a thermal window (Thermofenster) technique that cuts back on emissions treatment at certain temperatures—presumably to protect the engine against damage.

Although the Thermofenster technique is legal, investigators doubted that the chosen thermal windows are fully justified by engine protection, Minister Dobrindt said. Manufacturers concerned have been asked to take measures to restrict the thermal window to what is actually necessary. All affected German manufacturers have declared in writing that they will perform the required optimizations.

Manufacturers who use the Thermofenster technique will voluntarily recall approximately 630,000 vehicles produced in Europe for optimization of the emissions control. The German Kraftfahrt-Bundesamt (KBA) (Federal Motor Transport Authority) will check the improved emission control concepts for their effectiveness.

Prior to KBA approval of the optimized control software, a manufacturer must describe and explain the specific function in the control software to the KBA, as well as the reasons the manufacturer believes the engine protection is necessary.

The KBA will validate this. When in doubt, KBA will carry out additional measurements on the road with portable emission measurement technology (PEMS).

For the report, KBA investigators checked emissions from 53 models of Euro 5 and Euro 6 diesels. Measurements were taken on both the dyno as well as on the road.




Soooo,. ICEs may not be as clean as claimed? Have we been had for decades?


Do we know whether any of the vehicles tested had AdBlue systems? AFAIK, that is a sure way to combat NOx, although I accept that the effectiveness can vary across the driving cycle and engine load.

The sooner we move to mild (and stronger) petrol hybridisation the better. Couple this with vehicle lightweighting and we can have an effective short-term panacea for the worst of vehicle emissions until battery technology improves. I hope the EU goes hard on this, they can do this type of legislation better than America. They subsidised diesel makeup in the name of green outcomes, so start pushing PHEVs harder.


EDIT - that should be 'takeup' not 'makeup' - there's no camouflaging diesel's polluted image!

Plugin Curtis

Unfortunately, this is just one example where focusing solely on CO2 output per highway km (ie. cutting greenhouse gasses) has backfired, as overall pollution and other factors (such as diesel upstream environmental footprint) were ignored.

Any solution to Anthropogenic global warming should weigh environmental footprint (pre/during use/post use) as part of the decision making process!


When determining the consumption of a vehicle, standard test procedure is as follows:
1) Remove spare tire, car tools and car jack
2) Remove all seats of car except drivers seat
3) Replace tires with undersized types and over-inflate
4) Assure driver's (woman) weight does not exceed 50kg
5) Remove side mirrors
6) Once car has been started, remove battery
7) When test-driving on an oval or circular horizontal course, do not exceed 35mph. No unnecessary braking or accelerating.

What does such a test procedure have in common with actual driving??


In other words, testing should not be done by manufacturers but by 100% independent testers (paid by manufacturers) on a unit test basis.

A set or minimum of 3 testers should be used to arrive at a decent meaningful average.


I said it long time ago that diesel pollute a lot but it permit to a lot of peoples to find a high paying job in hospitals.


The UK DfT tests showed that on average all eu5 & eu6 vehicles tested produced 6 * the test cell levels of NOx when driven to the same test cycle.
VW used cycle identification
Others used a temperature window
They all produced similar high emissions, and VW were not the worse.
VW haven't said why they did it
Other manufacturers say they did it to protect the engine from damage.
Modern diesels are already prone to problems with the EGR and particulate filter blocking up with soot.
Reduces NOx emissions increases soot.
Governments are encouraging manufacturers to fix delivered vehicles to reduce emissions.
4 Questions:-
How is it that all manufacturers felt so invulnerable that the knew they could game the system without being caught?
Why did it take the Americans to catch them out?
If the loophole in the regulations is justified and legal, why didn't the manufacturers admit what was going on and save the governments a whole lot of wasted time and resources?
What will happen to the reliability (which is already suspect) when upgrades reduce the NOx and presumably increase soot?

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