Mercedes-Benz has stopped sales of the E 350d in Germany as it re-engineers the exhaust gas treatment system as part of a recertification process.
According to Autocar UK, the E 350d's 3.0-litre twin turbocharged V6 engine's exhaust management system is being re-engineered after Mercedes identified areas which it can change to lower the luxury sedan's nitrogen oxide (NOx) emissions.
A source told Autocar, that Mercedes will be fitting a larger SCR catalyst to the E 350d to help cut down the car's NOx emission levels.
A Selective Catalytic Reduction (SCR) catalyst helps convert nitrogen oxides in Nitrogen gas and water. A gaseous reducing agent (Mercedes uses a compound known as AdBlue which is 32.5 percent urea and 67.5 percent deionized water) is injected into the exhaust gases and is adsorbed into the catalyst.
The larger SCR catalyst provides a larger surface area for the atomisation of the AdBlue solution used by Mercedes which enhances the E 350d's ability to neutralise NOx emissions. Mercedes has also made changes to the injection process of the AdBlue solution to allow the system to run more efficiently.
However, Mercedes is not fitting a larger AdBlue solution tank to the re-engineered E 350d as the reworked system uses the same amount of the reducing solution in each injection as before. The Mercedes E 350d is fitted with a 24.5-litre AdBlue solution tank.
Merc's move to suspend sales of the E 350d may surprise some but it is a welcome move if it means a drop in nitrogen oxide emissions levels. While, there is no news when the India-spec E 350d LWB will get the revised emissions system, Mercedes should act on it as soon as possible.