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BlueTEC is Daimler AG's marketing name for engines equipped with advanced NOx reducing technology for vehicle emissions control in diesel-powered vehicles. The technology in BlueTec vehicles includes a selective catalytic reduction (SCR) system that uses diesel exhaust fluid, and a system of NOx Adsorbers the automaker calls DeNOx, which uses an oxidizing catalytic converter and diesel particulate filter combined with other NOx reducing systems.

The BlueTEC was on the Ward's 10 Best Engines list for 2007 and 2008.[citation needed]




In August 2007 VW Group announced that cooperation on BlueTEC with Daimler AG would end. The reasoning for this change is due to the recognition of the VW TDI branding. VW did not want to use a competitor's branding for a product they would introduce into the market.[2]

By 2010 a BlueTEC version of the Mercedes Sprinter was released. The BlueTEC systems allowed the elimination of much of the EGR in that vehicle's engine, which as a result gives 188 horsepower (140 kilowatts) compared to the non-BlueTec engine's 154 horsepower (115 kilowatts).[3]

Daimler Trucks uses BlueTEC on all its Freightliner and Western Star Trucks destined for highway use, as these vehicles are only available with diesel engines.[4]


The BlueTEC system was created because the properties of the Diesel cycle that give diesel engines high fuel efficiency also lead to relatively higher emissions of certain pollutants compared to Otto cycle engines. High compression ratios and lean air-fuel mixtures make high combustion temperatures, which results in more nitrogen oxides being produced during the combustion. While the particulate matter can be controlled with higher injection pressures and particulate filters, the big challenge is limiting NOx; Tier 2 regulations in the US are 0.05 grams per mile of NOx, which is ⅛ of the 0.40 limit in the European Union.[citation needed]


The emissions system works in a series of steps:

  1. A diesel oxidation catalyst reduces the amounts of carbon monoxide (CO) and hydrocarbons (HC) released from the exhaust.
  2. A DeNOx catalytic converter begins a preliminary removal of oxides of nitrogen.
  3. A particulate filter traps and stores soot particles, burning them off when the filter gets full.
  4. If the above are not sufficient to meet the prevailing emissions regulations, a Selective Catalytic Reduction (SCR) catalytic converter will convert the remaining nitrogen oxides to nitrogen and water; so-called diesel exhaust fluid (solution of urea and water) is injected into the exhaust gas stream to enable the conversion. In order to prevent vehicles from breaking emissions regulations, the engine may go into a limp-home-mode if the DEF tank is depleted; drivers are instructed to keep the tank refilled as necessary. Some commercial vehicles are equipped with a request or inhibit switch which allows the DEF injection to be "postponed" as it can reduce power output and increase temperatures temporarily; if the vehicle is climbing a grade, for example, it may be necessary to delay the cycle.


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