MB Bluetec in trouble here and in Europe

[Graham]

Probably doesn't affect most of the diesel owners her, but MB are being sued in USA and put under pressure in Europe, because it has been discovered that the highly touted Bluetec clean diesel emission system gets switched off when ambient temperatures drop below 10C (50F). MB says no cheating involved, because they test cars in accordance with rules - at 22C!

It apparently has something to do with the EGR system, but details are scarce.

Lawsuit alleges Mercedes-Benz diesels use defeat devices

Mercedes rejects real-world NOx criticism | Autocar

[MTUpower]

It's a lawsuit by a lawyer who is looking to make money. Nothing is proven and it looks like a throw some **** on the wall and see what sticks type of action by a slimy attorney.

[Graham]

Originally Posted by MTUpower

It's a lawsuit by a lawyer who is looking to make money. Nothing is proven and it looks like a throw some **** on the wall and see what sticks type of action by a slimy attorney.

The lawsuit here is no doubt like that. But it does appear that there is something wrong - this based on the Dutch company's findings and what Daimler have admitted. In other words - the Bluetec emission controls only work at temperatures above 10C. Below that, they get turned off. In many markets, these cars can see those temperatures ~50% of the time.

I own a GLK250 diesel (in Canada) and am surprised to find out that all that emission crap that these diesels are loaded with these days, only works 1/2 of the time.

[TimFreeh]

I'm thrilled that the system only works 50% of the time!!! I guess in the future the EPA is going to have to be a bit more specific in their testing procedures and certification process. I don't at all consider this to be "cheating", the specifications and testing procedures were published and Mercedes met the requirements.

[jay_bob]

Probably had something to do with preventing the system from freezing up due to all the cr@p being recirculated back into the intake...my guess is that they observed condensation from the water vapor in the exhaust collecting back in the intake tract and freezing in cold weather. Since this would result in a highly negative customer experience, and the specification gave them an out (test run at 22C), they took the card they were dealt and played it.

I suspect Mr. Dan Stokes can shed some light on this.

Designing to meet the spec (following it literally, not like what VW did) is not cheating. It is competitive survival.

[Graham]

Originally Posted by jay_bob

Probably had something to do with preventing the system from freezing up due to all the cr@p being recirculated back into the intake...my guess is that they observed condensation from the water vapor in the exhaust collecting back in the intake tract and freezing in cold weather. Since this would result in a highly negative customer experience, and the specification gave them an out (test run at 22C), they took the card they were dealt and played it.

I suspect Mr. Dan Stokes can shed some light on this.

Designing to meet the spec (following it literally, not like what VW did) is not cheating. It is competitive survival.

It's not clear just what part of emission controls gets turned off and why at 10C (no chance of freezing, but increased deposits of carbon likely?)

EGR systems do get carboned up with or without Bluetec. In trying to learn more, found this good write-up on Bluetec.

[babymog]

I must agree with the above posters. As an OE supplier, I design around a Daimler / Mercedes (et al) specification, usually more severe than I expect it will ever see. If I can exceed their specs, and can show capability in meeting their specs I'm ready for production.

Mercedes also designs to specifications, if the test is at 22C, you do all of your design/test/validation around that specification, not at -50C.

In my opinion, if the regulating authorities want the emissions met below 22C, then need to amend the specification and allow automakers time to re-design. This is like telling me that my parts need to meet spec. for 200,000miles, then someone with 500,000miles sees a failure and wants it replaced.

[Graham]

Originally Posted by babymog

Mercedes also designs to specifications, if the test is at 22C, you do all of your design/test/validation around that specification, not at -50C.

Sorry, but that is not logical.

Mercedes design their cars to operate in the conditions that they will experience wherever they will be sold. They then test them extensively in those conditions whether they be hot or cold to ensure the designs work. They are very good at that.

They made a lot of claims about their clean diesel technology, and fact that it does not work for good part of the year (whenever ambient temp is under +10C (not -50C!) in some of their largest markets, is not something they will easily explain.

Reading the reports from Europe, it seems the days of the modern diesel will soon be over. Emission regulations will have killed it. However, I will keep my GLK250 so long as it is still under warranty. Too darn complex.

[babymog]

Not logical? Mercedes was given a "P.I.S.", and they met it. Logical is all that it is.

I don't know how much of the "emissions system is switched off" below 10C, but it is unlikely that they belch coal. When Daimler sends me a P.I.S., I read the (lengthy) document, and we design to meet/exceed it, finished. If it is used outside of these parameters and a mechanical assembly has 5% more effort necessary to move it, that is not an issue or it would have been covered. For example, a ball-socket joint was required to have (IIRC) 3.5nm +/- .5nm over 35,000cycles from stop-to-stop in -40C to +85C. If it met (and showed capability) this spec I had succeeded. If someone decided to test it at +110C and the force dropped below 3nm, it is still fine.

I really don't know how much this affects emissions, but it meets the standard that was created. In my opinion it is not a failure other than politically.

[compu_85]

It's most likely just like the VW emissions system in that the adblue portion is switched off and NOx increases many many times. PM, CO, and HC emissions remain low.

-J

[Graham]

In another report, MB said:

Mercedes says the discrepancy is partly down to the exhaust gas recirculation (EGR) process operating differently between five and seven degrees centigrade, a process it says is aimed at protecting the EGR cooler. Official laboratory tests that define whether a car is legal are conducted at 22 degrees centigrade.

Mercedes says this practice is fully legal, and that it is required to ensure the regulated requirement of delivering full functionality of the exhaust gas after-treatment system up to at least 160,000 kilometres.

So perhaps condensation causing acidic conditions in intercooler is what they are trying to avoid?

This wouldn't likely have anything to do with the Adblue system, which is only a final cleanup. The emissions from these cars apparently almost met standards without it.

I am sure Daimler will be able to defend themselves in court. But in court of public opinion after the environmental guys get involved, they may have trouble selling or even being allowed to sell the Bluetecs in many markets.

[HuskyMan]

https://www.youtube.com/watch?v=FueX5RHASbo

[leathermang]

Rolling Coalers should watch out for road rage.... that is excessive and offensive in the extreme.

[Skid Row Joe]

Originally Posted by MTUpower

It's a lawsuit by a lawyer who is looking to make money. Nothing is proven and it looks like a throw some **** on the wall and see what sticks type of action by a slimy attorney.

X2

[TMAllison]

Complaint doesn't appear to effect W211 08 & 09 Bluetec's cause they don't have AdBlue. Wasn't added to W211 sedans until 2010