A recent report in Bild am Sonntag, a popular German newspaper, states that the US Department of Justice has said that engineers from Daimler have accused the company of using a cheat software program to tweak the emission readings of their diesel models.
Basically, this software enables the diesel models to pass UM emission tests for a limited period of time. During this time period, the car can pass all the emission control tests with flying colours. However, in the original state, the emissions are way above the legal limit. The software helps the diesel engines pass the tests through a manipulation of the catalytic reduction filter. This cheat software is similar to the one that VW has been caught using earlier. Bild am Sonntag says that the software program is based on the “Bit 13” function, which allows the engine to run in a very clean state for a limited period of time. It goes back to the original state after 16 grams of NOx is emitted in the controlled condition. The software works for exactly the same as the US highway testing cycle. The “Bit 14” function of the software helps the engine to switch to the dirty mode when running at preset temperatures and time periods. Through this, cars easily pass the FTP-75 warm test cycle. After the car has passed the US06 test cycle of less than 16 miles, the “Bit 15” function switches off the SCR exhaust gas treatment system.
Another software, Slipguard, is allegedly being used on many Mercedes Benz models to help them pass the emission norms.Slipguard lowers the emissions by detecting when the emissions of the car are being tested on a rolling road. Thru this system, a preset dose of urea-based AdBlue solution is introduced to the SCR exhaust gas after-treatment system to help the car comply with the emission standards set. So far, Mercedes Benz hasn’t issued an official comment on these allegations.