Mercedes Joins German Carmaker Emissions Train

Never content to allow trends to pass it by without a full-throttle attempt at keeping up – be it luxury SUVs, hybrid cars, or ├╝berfragmentation of market niches – German firm Daimler AG, which oversees automaker Mercedes-Benz, has just been implicated in its own nitrous oxide (NOx) emissions scandal, following the lead of compatriot Volkswagen and overseas upstart Tesla Motors.

As a result of the finding by Netherlands' Technical Inspection Institute (TNO) that the Mercedes-Benz C220 CDi BlueTec emits NOx at upwards of forty (40!) times the legally allowed level1 when the vehicle detects that the environmental temperature is less than 10 degrees Celsius (50 Fahrenheit), Der Spiegel (archived) reports that concerned citizens are already petitioning German automotive regulator Kraftfahrt-Bundesamt (KBA) to ban the offending vehicles from city centres when the environmental temperature is less than 10 degrees Celsius. Additionally, the petition aims to prohibit any further sales of the diesel C-classes for as long as they fail to comply, as unlikely as this may be to be implemented given the significant clout carried by Germany's top automakers.

Daimler denies that its creative solution to emissions are in any way specific to EU regulation tests, which are conducted at 22 degrees Celsius and therefore well in excess of the Mercedes-Benz engine management software threshold, and that its programs are therefore not "defeat devices" such as those found in competing Volkswagens.2 The Stuttgart-based Mercedes instead claims that its temperature-dependent diesel engine settings are for protection of the vehicle's motor and that any reading of the TNO report to the contrary is a "misinterpretation".

Were it not for the millions and millions of lines of the stuff, one would be inclined to suggest that regulators read the code before approving anything for real-world use as this is the only way to live ; but as the injuries inflicted plunge ever deeper and the cries of "'tis but a flesh wound" become ever less believable, it would be hard to argue that regulators have any intention of continued survival.


  1. TNO recorded NOx levels of 2`000 mg / km. Increased NOx exposure is correlated with increased lung cancer rates. 

  2. Volkswagen's "defeat devices" specifically detected when its diesel vehicles were on a "rolling road" such as those used during laboratory-based emissions testing by the fact that only the front wheels were in motion under such circumstances. This obviously artificial condition, where the real wheels were motionless but the car was still on and the engine was still under load, would trigger an additional exhaust cleaning program in the affected models, thereby reducing power and torque but also making "clean diesels" possible, at least as far as marketing was concerned. 

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