With New Measuring Methods Against Exhaust Gas Tricks

Table of contents:

With New Measuring Methods Against Exhaust Gas Tricks
With New Measuring Methods Against Exhaust Gas Tricks

Video: With New Measuring Methods Against Exhaust Gas Tricks

Video: With New Measuring Methods Against Exhaust Gas Tricks
Video: Exhaust Gas Analysis for Basic Students 2023, December

Car manufacturers have to significantly reduce CO2 emissions. Mercedes has now presented how this is to be achieved in Stuttgart.

Why there has to be a significant reduction in exhaust gas values can be seen at the Neckartor in Stuttgart, a now famous traffic junction, a nationwide symbol for the pollution of local residents by fine dust and nitrogen oxides.


It was and is repeatedly mentioned in the same breath as impending driving bans. The measuring station is right next to the road on which traffic is almost constantly jammed in front of a red light. It is pure coincidence that the traffic is just rolling when this very special Mercedes GLE passes the state sniffing sensors. This time the carmaker has his own devices with him, mounted on the towbar of the big SUV. A bulky box breathes in everything that the three-liter diesel leaves from the fuel via a direct hose connection to the tailpipe of the exhaust.

Mercedes GLE on the road with PEMS

The GLE has put a so-called "PEMS" on the hook. This stands for “portable emissions measurement system”, ie a device that constantly registers all pollutants outside the car and thus differs from the permanently installed stations. With the device, automakers are going on the new test round, which is now required by the authorities as proof that a car in everyday traffic does not exceed the specified limit values.

Consumers across Europe have to remember a new abbreviation if they want to be sure when buying a car that their family member on wheels is future-proof. The process is called “RDE”, an abbreviation for “Real Driving Emissions”. In contrast to previous tests on the test bench, what is actually happening behind the car is to be checked. When accelerating, in traffic jams, at higher speeds on the motorway, in heat and frost, at sea level or in the mountains.

End of the trickery

Exhaust gas measurement on a diesel. Photo: dpa
Exhaust gas measurement on a diesel. Photo: dpa

Take Mercedes, for example: the car manufacturer with its often powerful models employs hordes of test engineers who have to spend thousands of kilometers checking the work of their colleagues in the development department. It is not just about meeting the strict requirements of the authorities, but also about restoring customer confidence. Because the new test procedure is intended to prevent people from being tricked and cheated on. If the measurements were previously carried out on the test bench in a closed laboratory, the cars now have to go into real life.

There is no longer a chance for cheating software, as in the case of Volkswagen, which recognizes whether a car is currently being tested on a test bench and therefore electronically regulates everything that produces excessively harmful exhaust gas. Later on on the street, the program switched back to normal and blew unhindered a multiple of the official value into the breath of the people and animals around it. We know all of this under the heading of the “diesel scandal”.

Tests outside the laboratory conditions

Sinister machinations should be a thing of the past if a car successfully passes the RDE test today, which must also be confirmed by independent institutions. So no fraud behind the factory gates. The evaluation of the test round around the Neckartor mentioned shows how complicated the whole process is. The emission of the notorious nitrogen dioxide, for example, changed constantly depending on the driving style or traffic situation. All data summarized then result in the valid mean value for the specific vehicle. And that must remain below a specified value so that the model in question meets the new Euro 6d-temp emissions standard.

The main purpose of the new reality test is to check the values measured in the test laboratory as before. Only if a car proves itself on the road is Euro 6d-temp in the official registration papers. Important for future legal penalties such as driving bans or restricted areas. But the classic test procedure, which in the past led to unrealistic results and facilitated fraud, was drastically changed.

It is driven longer and faster

Cars tested according to the new WLPT standard now have to cope with much more stringent tests on the test bench. It is driven longer and faster, and high speeds must now be included in the consumption rating. No more fuel-efficient cuddling course, the left lane of the German autobahn is now also being measured. So it's no wonder that all new vehicles registered since September last year now consume more on paper than before. Because at this point in time the WLPT standard came into force.

The result: Numerous models from the manufacturers had to be temporarily removed from the sales program because the companies could no longer keep up with the new measurements of all their cars. Test stands became scarce. Vehicles that were produced but not yet certified according to the new standard were temporarily stored in huge spaces such as near the construction site of the scandalous airport in Berlin. The registrations went into the basement in autumn, only gradually the car companies were able to deliver their full range of models again. Some versions even had to be completely deleted because they technically had no chance of meeting the new standard.

Now Mercedes sees the light again at the end of the tunnel. With 190 models in different series, the Stuttgart-based premium manufacturer had the largest number of vehicles approved according to WLTP on offer. In comparison: BMW had 144 in January and Audi 79.

The diesel remains important

Ultimately, all of this serves to ensure that cars will continue to be sold successfully in the future under the ever more stringent government regulations. Since certain values for so-called fleet consumption (all models offered by a manufacturer) must not be exceeded today, Mercedes and Co. have to bring thousands of electric cars, plug-in hybrids and vehicles with a 48-volt electrical system onto the streets.

This is the only way for extreme athletes from AMG or the large luxury models such as an S-Class to have a future, because they can be offset against E-models. And since the diesel engine of the classic cars with combustion engines is still unbeatably fuel-efficient and therefore has advantages over gasoline-powered cars when it comes to CO2, its development is continuing. And because it is now being measured so strictly, the confidence of car buyers could also return. (SP-X)