Then I switch off - the "thermal window" in the car

The term “thermal window” actually exudes some positive attributes such as energy saving, comfort and environmental protection. In connection with the internal combustion engine, however, the signs are quite different. Every modern car is equipped with an outside temperature sensor that informs us in good time of possible slippery roads. At the same time, the current temperature value is also transmitted to the engine control in the combustion engine in order to control optimal combustion and to reduce nitrogen oxides in the exhaust gas. According to an EU guideline, the legislature has so far allowed manufacturers to temporarily switch off nitrogen oxide filtration under defined conditions.

Measurements by the Federal Motor Transport Authority in 2016

During the exhaust gas measurements under practical conditions of the Federal Motor Transport Authority on 58 models from mainly popular manufacturers, in addition to the well-known "cheat software" that recognizes the test scenario based on certain criteria, a much simpler variant of exhaust gas manipulation occurred according to various media reports. In the DIN test conditions, the exhaust gas value is always measured at a constant temperature of 23 degrees Celsius. Nothing seems simpler than optimizing the exhaust gas cleaning in a temperature window around this area and not further optimizing it outside certain limits or even switching it off. The manufacturers justify this in part with the protection of engine components.

The test results were published on Friday, April 22nd, 2017 by Transport Minister Alexander Dobrindt. If the suspicion is confirmed, it is no longer surprising that the exhaust gas pollution in city centers is sometimes well above the permissible limit values.

The German manufacturers are recalling around 630.000 vehicles to expand the thermal windows, including vehicles from Audi, Porsche, Mercedes, Volkswagen and Opel.

Update March 2017

The measurement results of the German environmental aid from the winter of 2016/2017

Extract from the press release of the German Environmental Aid:

In January 2016, the DUH revealed for the first time the illegal shutdown of a proper exhaust gas cleaning system at Mercedes, and meanwhile at all examined manufacturers of diesel cars. Fiat / Chrysler deactivates below +19 degrees Celsius, Opel, Daimler (Mercedes A- / B-Class), Porsche and Renault below +17 degrees Celsius and Daimler (from C-Class) below +10 degrees Celsius. These are clearly illegal defeat devices. 
The measurements of the DUH as part of its Emissions Control Institute (EKI) therefore took place at outside temperatures between -5 degrees Celsius and a maximum of +16 degrees Celsius. 15 diesel cars with the Euro 6 emissions standard and one Euro 5 vehicle were examined. 

Two of the three dirtiest vehicles from German production come from Daimler: the negative front runner in this group is the Mercedes B 180 d (1.039 mg NOx / km) with a limit value exceeding 13 times. The Opel Zafira Tourer 1,6 CDTi (995 mg NOx / km) exceeded this figure by 12,4 times and finally the Mercedes C 220 d (770 mg NOx / km) exceeded it by 9,6 times.

The four dirtiest diesel vehicles in total do not even comply with the 1992 Euro 1 limit. The negative overall record holder is the Fiat 500X 2.0 Cross 4 × 4 with a value of 1.380 mg NOx / km and thus 17,2 times the legally prescribed EU limit value of 80 mg NOx / km. This is followed by Renault Captur 1.5 dCi 110 with 1.316 mg NOx / km (16,5 times exceeding the EU limit value), Volvo S90 4D with 1.076 mg NOx / km (13,4 times exceeding), Mercedes B 180 d with 1.039 mg NOx / km (13-fold excess). 

Two vehicles comply with the EU limit value and thus show that effective exhaust gas cleaning is technically feasible even in winter temperatures: the Mercedes E-Class 200d of the new engine generation (654) with 43 mg NOx / km and the Audi A5 2.0 TDI with 40 mg NOx / km. 

Exhaust gas measurements by the Emissions Control Institute (EKI) of the German Environmental Aid
in the winter half of 2016/17 on 16 diesel cars with the EURO-6 standard

List sorted by limit value excess factor in descending order.

Additional information on the values:
* Emission standard Euro 5, NOx limit value at 180 mg / km
** CO2 value subject to change
Source: Deutsche Umwelthilfe, measurement period September 2016 - March 2017

The results show the following tendencies:

• Legally compliant exhaust gas values ​​can only be achieved if the complex and necessary technology for consistent exhaust gas cleaning is installed across all temperature ranges
• The basic price for the only two emission-compliant models is 200 euros for the Mercedes 44.565d and 5 euros for the basic equipment for the Audi A2.0 40.850 TDI, and the extra price compared to the petrol variants does not pay off for private cars with a few kilometers per year.
• In addition to the diesel costs, the maintenance costs for the Adblue technology and the consumption costs for Adblue must be added for all diesel engines of the new generation.

Addendum:

Sources: Press release and test results from Deutsche Umwelthilfe

The measurement results of the German environmental aid as a beacon diagram

Cover picture: Take-off from the diesel vehicle. Source: © Ingo Bartussek @ Fotolia.com

Note:

You can find an up-to-date overview of all emission-free electric vehicles in the new issue of green car magazine issue II / 2017

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N. Hawthorn

Author on the topics of sustainable mobility and new mobility concepts.

Questions and suggestions under 01575/287 3616 or by email to leser@greencarmagazine.de.

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