• + Turbo innovations boost emissions control
  • + Partnership working creates Euro V compliance through EGR

High Pressure Success

Posted 08.12.2009

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Honeywell engineers have developed an innovative two stage turbo system that is enabling leading truck manufacturer MAN to achieve Euro V emissions compliance purely through exhaust gas recirculation (EGR). The latest generation MAN 11-liter and 13-liter diesel engines incorporate turbo technologies that obviate the need for a conventional Selective Catalytic Reduction (SCR) after-treatment system, creating significant advantages in terms of space and operational efficiency.

High Pressure Success

Two-stage turbocharging, of course, is not unique for the commercial vehicle segment – but working with MAN engineers Honeywell has succeeded in matching two small wastegate turbos in a series sequential system to drive the extremely high boost pressures needed to optimize the benefits of EGR.

EGR is a key factor in emissions control and works by recirculating a portion of an engine’s exhaust gas back to the engine. When mixed with incoming air, this has the effect of lowering the peak combustion temperature, so limiting the generation of NOx.

Key to performance in the MAN turbo system is the use of an interstage cooler that reduces gas flow temperatures to the secondary compressor to help drive boost pressures. The system also enables crankcase gases to be channelled through the compressor, improving emissions control still further.

High Pressure Success

“The requirement to control emissions purely through EGR dictated the need for high levels of EGR at low engine speeds and this meant that we had to match to two relatively small turbos in order to create the necessary low end boost pressures,” said Chris Wilkin, Honeywell Application Engineering Manager. “The result is a turbo system that obviates the need for an SCR system and its associated components, such as a reagent holding tank. This enables haulage companies to go about their business without having to worry about the availability of additives required by SCR.”

Central to the success of this project was Honeywell’s CV centre of excellence in Brno in the Czech Republic, which is home to some of the most advanced technical facilities in the world. The team had a MAN D26 engine on permanent test at the facility during the program.

“One of the most satisfying aspects of this program was the close cooperation between the Honeywell team and MAN. By working in partnership, we have delivered a truly customized solution that sets new standards of innovation in emissions control,” said Chris Wilkin.

Photo Credit: Honeywell, MAN Trucks