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DUH charges Zafira diesel emits up to 17x more NOx than permitted under certain conditions; Opel rebuts with its own testing

German environmental NGO Deutsche Umwelthilfe (DUH) (earlier post) has charged that an Opel Zafira 1.6 CDTi diesel (Euro 6b) emits up to 17 times more NOx under certain driving situations than permitted by the Euro 6 limit value. Dynamometer testing for DUH was conducted at the Bern University of Applied Sciences (Berner Fachhochschule).

In three tests under the NEDC cycle with rotating rear wheels, the Zafira emitted between 2 to 4 times more NOx than allowed, according to the test report released by DUH. In three additional tests under normal test conditions—and thus with non-rotating rear wheels—however, the NOx values were below the legal value limit of 80 mg/km in each case.

DUH
Select raw NEDC test results. Source: DUH. Click to enlarge.

The testers also observed that, with non-rotating rear wheels and with a continuous increase in the speed to 150 km/h (93 mph), NOx emissions increased abruptly and exceeded the measuring scale of the analysis instrument. The report suggested that such behavior could be explained by a shutdown of the AdBlue (urea) dosing unit. Similar behavior was not detectable when operated in the 4-wheel drive mode.

The measurement results show that the vehicle behaves differently when the dynamometer is operated in the 4- or 2-wheel drive mode. The measurements carried out show the following trend: The NOx emissions in the NEDC cycle depend on the test mode of 2WD/4WD. In the 2-wheel drive mode the vehicle met the NOx regulations. At low speeds, NOx emissions are not always identical, and are likely to depend on the activity or the storage effect of the SCR system. The behavior of the SCR system seems to be dependent on the test mode, since the NOx trends are different in the two test stand modes of operation.

—Berner Fachhochschule

DUH has submitted the report to Germany’s KBA (Kraftfahrt-Bundesamt), Germany’s Federal Motor Transport Authority.

Opel response. In response, Opel “sharply” (scharf) rejected the DUH charges, asserting again that GM developed software has no features that detect whether the vehicle is undergoing an exhaust emissions test.

The results of the alleged Zafira test conducted by the German Environmental Relief (DUH) are not comprehendible. It is not fair that the German Environmental Relief makes assertions but did not disclose the alleged results, despite us asking for them on multiple occasions.

—Opel statement

Opel engineers put a corresponding vehicle (a Zafira with a 1.6-liter Euro 6 diesel engine) on the test bench in the presence of TÜV Hessen and conducted and protocoled additional tests in accordance with the regulations both on a two-roller and a four-roller test bench. These results showed compliance with the legal limits both for testing on two-wheel or four-wheel setups.

This is the only result to be expected, as it has no influence on the emission systems whether or not the rear wheels are in motion. This means: The allegations are clearly false and unfounded.

—Opel statement

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Comments

HarveyD

As with other pollution measurements and tests, nobody should rely on manufacturers in house test results.

It is inherent, to the behavior of the beast, to cheat instead of spending more efforts and $$$, to improve their products to the level required to meet the legal standards.

This is just one more example of what is going on. All the in house tests should be redone by government and/or independent labs. Manufacturers should pay for all qualifying tests, not the tax payers.

All current and past cheaters should be penalized, not only VW.

mahonj

I'll bet VW are hoping a bunch of these are unearthed.

clett

I think that might be why VW were so quick to admit they had the defeat device - they were aware that other manufacturers were up to the same trick too.

Engineer-Poet

Given the (alleged) tight compartmentalization of the conspiracy in VW, it may be a case of convergent evolution:  everybody knew it was possible, so lots of people did it.

DaveD

It is so incredibly obvious that diesel is dirty and they can dress it up anyway they want in marketing campaigns. But it's nearly up there with being a flat earther to actually believe that crap.

I've always bee stunned that people bought into it.

Engineer-Poet

DaveD ignores this:

In three additional tests under normal test conditions—and thus with non-rotating rear wheels—however, the NOx values were below the legal value limit of 80 mg/km in each case.

It is abundantly clear that the vehicle was capable of meeting the NOx standard, it was just programmed to save DEF instead and make drivers happy.

DaveD

EP,
Are you being sarcastic? So they passed SOME tests while simulating idle conditions with non-rotating rear wheels. And I would give them a pass on all the tests they failed...why???

Engineer-Poet

My turn to ask you if you're reading the same report I am.  There's no difference mentioned in engine operating point (speed/BMEP); the only difference is if the vehicle parameters matched test conditions or road conditions.  Under the test conditions, it met the NOx standard.

From this I conclude that the vehicle was capable of meeting the emissions standard under almost all conditions, it was just programmed not to in order to save DEF and make the buyers happy.  Is that really so hard to understand?

DaveD

I see why you picked Willy.

bundy

"From this I conclude that the vehicle was capable of meeting the emissions standard under almost all conditions". Dream on!

Engineer-Poet

And why shouldn't it?  All the testers had to do to get emissions under the 80 mg/km limit was to engage AWD mode, forcing the rear wheels to rotate and defeating the test-mode bypass detection.

bundy

why should it? The pass or fail depends on the final accumulated values divided by the distance travelled. This simply means that even if certain driving conditions are giving high HC or NOx, it is still not the end of world.

Since you are still confident that the car in question can meet emissions in all conditions, can you verify that these all conditions also cover: -
1) The first 10 seconds when the catalytic converter is still cold
2) The high load conditions for example, acceleration and highway phase
3) PM number and mass during acceleration

Engineer-Poet

In other words, you're changing the conditions of the test.  Vehicles are explicitly allowed to violate the "normal" emissions limits during conditions like cold start.

bundy

Poet, people like me meet up with other people like me from around the world annually in Detroit, Aachen, Vienna and Yokohama. We do not talk rubbish like you do and we dont undermine others who are doing things repeatedly everyday to make things better.

There is no such thing as changing the test condition. The tests are standardized depending on the European, US or Japanese test cycles.

What you described as violation is acceptable to authorities around the world provided that the average is still within limits. The authorities are also made up of good technical people who understand the limitations of available emission control technologies.

Since you want others to think that you are smart and knowledgeable, can you come up with an aftertreatment that does not need any light off? Try to come up with solutions rather than arguing to twist things into your favor.

Engineer-Poet

bundy, a catalyst-equipped vehicle will always "fail the first bag" because the cat is cold.  That is normal and does not fail the test as a whole; if you decide that this is now a disqualifier it IS a change to the test.

I don't have to think about ways to eliminate light-off, it was done long before I ever thought about it.  I've seen catalyst packs with fat electric terminals suitable for taking starter-motor cables.  Electrically preheated catalysts are an option if the price in battery bulk and life ever becomes worth paying.  I get the feeling it never will.

As for the vehicle itself, I repeat the text of the article:

In three tests under the NEDC cycle with rotating rear wheels, the Zafira emitted between 2 to 4 times more NOx than allowed, according to the test report released by DUH. In three additional tests under normal test conditions—and thus with non-rotating rear wheels—however, the NOx values were below the legal value limit of 80 mg/km in each case.

In other words, the non-compliance was obviously due to a defeat mode in the ECU software, not a problem in the emissions-control hardware.  The hardware was capable of meeting the NOx standard, it was just programmed not to.

bundy

I am growing tired here of your word twisting again, failing the first 10 seconds of the test will not mean failing the whole test because the final number that matters is the average.

I have done a lot of works on electrically heated catalyst. Though Emitec/Ferrari published a work on preheated arrangement, such possibility is not feasible for real life application. If this is the best that you can come up with, there is still no solution from you except of more annoying noises and whining.

As for whether the hardware is not programmed to, looks like you have not spend enough time inside the emission lab. Believe me there are still limitations with aftertreatment hardware that may prompt VW into doing what they were doing. Yet, I still wont consider using device defeat if it does not involve safety risk.

Most of us also found the emission test cycle is hard enough and it consumes most of our time.with limited resources and time, there is just not enough time to cover every single conditions and scenario. We work based on objectives and by the time we are done, either we are close to the deadline or we are already pass the deadline.

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