BlueTEC

BlueTEC is the Mercedes-Benz marketing name for diesel powertrains equipped with systems intended to reduce nitrogen-oxide emissions. It is not a standalone vehicle marque or fuel retailer, but a technology brand applied to diesel engines in passenger cars, sport utility vehicles, vans, and commercial vehicles. Depending on the vehicle and generation, the BlueTEC package has combined several exhaust-treatment technologies, including a diesel oxidation catalyst, a diesel particulate filter, nitrogen-oxide storage or adsorption catalysts, and selective catalytic reduction (SCR). SCR systems inject diesel exhaust fluid, an aqueous urea solution commonly known as AdBlue or DEF, into the exhaust stream so that nitrogen oxides can be converted primarily into nitrogen and water. Earlier BlueTEC implementations also used a DeNOx system based on nitrogen-oxide adsorption and catalytic oxidation. The exact hardware and control strategy varied by model, market, engine family, and emissions standard. Daimler introduced BlueTEC-branded vehicles to the North American market at the 2006 North American International Auto Show. The initial applications included the Mercedes-Benz E-Class, which used a DeNOx-oriented system, and the GL-Class, which used SCR. Their regulatory status differed by state because California and states following California emissions rules imposed stricter requirements than many other U.S. jurisdictions. The technology was promoted as a way to combine the fuel-efficiency advantages of diesel engines with substantially lower regulated exhaust emissions. BlueTEC powertrains subsequently appeared in Mercedes-Benz passenger vehicles and, by around 2010, in the Sprinter van range. The system addressed a technical problem inherent in diesel combustion. Diesel engines generally operate with excess air, or a lean air-fuel mixture. That operating condition supports fuel efficiency but prevents the use of the conventional three-way catalytic converter that is highly effective on stoichiometric gasoline engines. Reducing nitrogen oxides solely through engine calibration can also impose a fuel-economy or performance penalty. BlueTEC therefore used a sequence of after-treatment stages: oxidation catalysts reduce carbon monoxide and hydrocarbons; particulate filters capture soot and periodically burn it off; DeNOx catalysts or SCR units address nitrogen oxides. In SCR-equipped vehicles, the driver must keep the DEF reservoir supplied, and the vehicle may restrict operation if the fluid is exhausted. Daimler also entered a technology-sharing arrangement with Volkswagen and Audi during the effort to expand diesel passenger-car sales in the United States. Volkswagen presented BlueTDI-related vehicles under that cooperation, including versions of the Jetta, Tiguan, and Touareg. The partnership ended in 2007, after which Volkswagen emphasized its own TDI branding and developed separate emissions-control strategies. BlueTEC was recognized by Ward's as one of its 10 Best Engines in both 2007 and 2008. The brand later became associated with regulatory and legal controversy. On-road testing by the Dutch testing organization TNO found that a Mercedes-Benz C-Class C 220 CDI BlueTEC produced nitrogen-oxide emissions far above its laboratory result under cold-weather conditions. Mercedes-Benz argued that the relevant control behavior was permitted at temperatures below 10 degrees Celsius. In 2016, the U.S. Department of Justice asked Mercedes-Benz USA to investigate its diesel-emissions certification and admission processes. Separate private litigation alleged that BlueTEC vehicles used emissions-control strategies that improperly reduced emissions performance outside laboratory conditions. The U.S. litigation ultimately received approval for a settlement in 2021, and a similar Canadian settlement was reached in 2022. BlueTEC therefore represents both a significant diesel emissions-control technology platform and a prominent case in the wide…

BlueTEC emerged as Daimler's branded response to the difficulty of meeting tighter diesel-emissions requirements without abandoning the fuel economy and torque advantages associated with diesel engines. Unlike gasoline engines, which can use a three-way catalytic converter under stoichiometric combustion conditions, diesel engines normally operate with excess oxygen. That oxygen-rich exhaust makes conventional nitrogen-oxide conversion more difficult. BlueTEC addressed the problem through a combination of engine calibration and exhaust after-treatment rather than through a single universal component. The technology was introduced publicly in North America in 2006 on Mercedes-Benz E-Class and GL-Class applications. These vehicles represented two different technical approaches. The E-Class application used a DeNOx arrangement centered on nitrogen-oxide storage and catalytic treatment, while the GL-Class application used selective catalytic reduction. SCR requires the injection of diesel exhaust fluid, a water-and-urea solution, into the exhaust. Under suitable conditions, the fluid helps convert nitrogen oxides into nitrogen and water. The choice of system depended on packaging, engine characteristics, vehicle class, market requirements, and the applicable emissions rules. A typical BlueTEC exhaust line could contain several stages. A diesel oxidation catalyst treated carbon monoxide and unburned hydrocarbons. A diesel particulate filter captured soot and periodically regenerated by burning the accumulated material. A DeNOx catalyst reduced or stored nitrogen oxides, while an SCR catalyst could provide an additional or principal nitrogen-oxide conversion stage. Vehicles using DEF required owners to maintain the fluid level. If the reservoir was depleted, control software could restrict vehicle operation or place the vehicle in a reduced-performance mode so that the vehicle would not continue operating indefinitely without the required emissions reagent. Daimler sought to broaden the U.S. diesel passenger-car market through cooperation with Volkswagen and Audi. Vehicles associated with the program included Volkswagen's Jetta Clean TDI, a Tiguan concept, and the Touareg BlueTDI. Some used nitrogen-oxide adsorbers, while the Touareg used SCR. The arrangement was short-lived: Volkswagen announced in 2007 that it would stop using the cooperative BlueTEC branding and would emphasize its own TDI identity. Volkswagen subsequently pursued separate emissions-control development, an episode that later became relevant to the wider history of diesel emissions scandals. BlueTEC was applied beyond Mercedes-Benz passenger cars. By 2010, the Mercedes-Benz Sprinter was offered in a BlueTEC configuration. The system's ability to reduce reliance on exhaust-gas recirculation in that application was associated with a higher stated power output than the non-BlueTEC version in the source material. The technology also received industry recognition when a BlueTEC-equipped engine appeared on Ward's 10 Best Engines list in 2007 and again in 2008. The brand's history changed direction as regulators and researchers increasingly compared laboratory certification with on-road emissions. In the Netherlands, TNO tested a Mercedes-Benz C 220 CDI BlueTEC and reported nitrogen-oxide emissions more than forty times higher than the laboratory result in the tested conditions. The test took place at temperatures below 10 degrees Celsius. Mercedes-Benz maintained that the relevant emissions behavior at such temperatures was permissible, but the findings contributed to questions about temperature-dependent emissions controls and the real-world performance of diesel systems. In the United States, private plaintiffs filed a lawsuit in February 2016 against Daimler, Mercedes-Benz, and Bosch entities, alleging that BlueTEC vehicles violated emissions standards through strategies similar to those implicated in the Volkswagen emissions scandal. A federal judge dismissed the case without prejudice in December 2016 because the plaintiffs had not established standing. The litigation was later revived after an amended complaint. Separately, Mercedes-Benz USA disclosed that the Department of Justice had asked the company to review its diesel emissions-certification and admissions processes. Reports in 2018 alleged that investigators had identified software functions that could recognize test conditions or alter emissions operation after a defined distance, although the allegations and legal consequences varied by vehicle and proceeding. The U.S. litigation concluded with court approval of a class-action settlement in July 2021. The approved package included cash payments for eligible current and former owners, free emissions-system retrofits, and extended warranties. A comparable Canadian settlement was reached in February 2022. BlueTEC consequently remains significant both as a technical brand in the development of diesel exhaust treatment and as a case study in the regulatory, legal, and reputational risks created when certified emissions results diverge from real-world performance.

• 2022

  Canadian settlement reached

  [1]BlueTECen.wikipedia.org

  A similar settlement concerning affected BlueTEC vehicles was reached in Canada.

• 2021

  U.S. settlement approved

  [1]BlueTECen.wikipedia.org

  A federal court approved a settlement providing payments, emissions-system retrofits, and extended warranties for affected vehicles.

• 2016

  U.S. private litigation begins

  [1]BlueTECen.wikipedia.org

  Private plaintiffs brought a U.S. lawsuit alleging that BlueTEC vehicles used improper emissions-control strategies.

• 2010

  BlueTEC Sprinter introduced

  [1]BlueTECen.wikipedia.org

  Mercedes-Benz expanded the technology to the Sprinter commercial-van range.

• 2007

  BlueTEC receives Ward's engine recognition

  [1]BlueTECen.wikipedia.org

  A BlueTEC-equipped engine was selected for Ward's 10 Best Engines list, with the recognition repeated in 2008.

• 2007

  Volkswagen ends BlueTEC cooperation

  [1]BlueTECen.wikipedia.org

  Volkswagen Group announced the end of its cooperation with Daimler on BlueTEC and moved toward its own TDI branding and technology.

• 2006

  North American BlueTEC debut

  [1]BlueTECen.wikipedia.org

  Daimler introduced BlueTEC applications for the Mercedes-Benz E-Class and GL-Class at the North American International Auto Show.

A Mercedes-Benz diesel technology brand positioned around lower nitrogen-oxide emissions, diesel fuel efficiency, and compliance with increasingly stringent vehicle-emissions standards.

• Diesel emissions-control technology · 2006

  BlueTEC DeNOx diesel system

  A BlueTEC configuration used a nitrogen-oxide adsorption and catalytic-treatment strategy, supported by other exhaust components such as an oxidation catalyst and particulate filter. The E-Class application introduced in North America used this type of DeNOx approach. It was designed to store or chemically reduce nitrogen oxides during engine operation and regeneration phases, enabling the vehicle to meet the emissions requirements applicable to its market and model.

• Selective catalytic reduction · 2006

  BlueTEC SCR system

  The SCR form of BlueTEC injects diesel exhaust fluid into the exhaust stream. The resulting chemical reaction converts nitrogen oxides primarily into nitrogen and water. The system is used with other treatment stages, including oxidation catalysts and particulate filters. Because it depends on a replenishable fluid reservoir, vehicles provide warnings and may limit operation when the required fluid is not maintained.

• Passenger-vehicle powertrains · 2006

  Mercedes-Benz BlueTEC passenger vehicles

  BlueTEC was applied to Mercedes-Benz diesel passenger vehicles including the E-Class, GL-Class, and C-Class. The hardware differed across generations and markets, but the common positioning was to combine diesel efficiency with lower regulated emissions through integrated exhaust after-treatment.

• Commercial-vehicle powertrain · 2010

  Mercedes-Benz Sprinter BlueTEC

  The BlueTEC name was extended to the Mercedes-Benz Sprinter around 2010. In the cited application, the emissions system reduced the need for extensive exhaust-gas recirculation and was associated with a higher stated engine output than the corresponding non-BlueTEC version.

• 2018

  Reported allegations concerning emissions software

  German media reported allegations that U.S. investigators had identified software functions in Mercedes-Benz diesel vehicles that could recognize test conditions or deactivate emissions controls after a specified driving distance. The reports described disputed allegations rather than a single definitive finding covering every BlueTEC vehicle.

  Source

• 2016

  TNO real-world emissions findings

  Dutch testing organization TNO reported that a Mercedes-Benz C 220 CDI BlueTEC emitted more than forty times its laboratory nitrogen-oxide result during on-road testing below 10 degrees Celsius. Mercedes-Benz stated that the temperature-related emissions behavior was permissible.

  Source

• 2016

  U.S. emissions investigation and litigation

  The U.S. Department of Justice requested that Mercedes-Benz USA review its diesel emissions-certification processes, while private plaintiffs alleged that BlueTEC vehicles used unlawful emissions-control strategies.

  Source

Read more

• 2021

  Resolve U.S. BlueTEC class litigationOther

  Background

  Private plaintiffs alleged that affected BlueTEC vehicles did not comply with emissions requirements under real-world conditions.

  Action taken

  A federal court approved a settlement providing cash payments, emissions-system retrofits, and extended emissions warranties for eligible owners.

  Aftermath

  The settlement resolved the U.S. class-action process while leaving BlueTEC associated with heightened scrutiny of diesel emissions certification and on-road performance.

  Source

• 2007

  End Volkswagen Group BlueTEC cooperationStrategy

  Background

  Daimler, Volkswagen, and Audi had cooperated to encourage diesel passenger-vehicle adoption in the United States.

  Action taken

  Volkswagen Group announced that it would end the cooperation and use its own TDI branding for relevant products.

  Aftermath

  The two manufacturers pursued separate diesel technology and marketing strategies.

  • Volkswagen Group — Volkswagen shifted emphasis to its own TDI identity and independently developed emissions-control systems.

  Source

• 2006

  Launch BlueTEC in North AmericaProduct launch

  Background

  Daimler sought to offer diesel vehicles capable of meeting increasingly strict U.S. emissions requirements while retaining diesel fuel economy.

  Action taken

  The company introduced BlueTEC-equipped E-Class and GL-Class vehicles using different nitrogen-oxide reduction architectures.

  Aftermath

  The launch established BlueTEC as a technology brand across Mercedes-Benz vehicle lines and created a platform for later passenger-car and commercial-vehicle applications.

  Source

• 2010

  BlueTEC reaches the Mercedes-Benz Sprinter[1]BlueTECen.wikipedia.org

  Product launch

  A BlueTEC version of the Mercedes-Benz Sprinter became available, with the emissions system allowing a higher-output engine configuration than the non-BlueTEC version described in the reference material.

• 2007

  BlueTEC named to Ward's 10 Best Engines list[1]BlueTECen.wikipedia.org

  Other

  A BlueTEC-equipped engine was included in Ward's 10 Best Engines list, an honor repeated in 2008.

• 2007

  Volkswagen Group ends BlueTEC cooperation with Daimler[1]BlueTECen.wikipedia.org

  Other

  Volkswagen Group announced that it would end its cooperation with Daimler on BlueTEC technology and place greater emphasis on its own TDI branding and systems.

• 2006

  BlueTEC introduced in Mercedes-Benz North American vehicles[1]BlueTECen.wikipedia.org

  Product launch

  Daimler presented BlueTEC applications for the Mercedes-Benz E-Class and GL-Class at the North American International Auto Show, using different nitrogen-oxide reduction approaches.

1. 1BlueTECen.wikipedia.org