Tenneco Automotive has integrated a catalytic converter and exhaust silencing components in one unit for commercial vehicles.

The company has developed a silencer that meets demanding acoustics, backpressure and flow distribution requirements necessary to make DaimlerChrysler's SCR system compliant with both Euro 4 emissions regulations and acoustics limits. This includes the integration of the SCR catalyst into the silencer, and the distribution of exhaust gas on the catalyst to meet the conversion rate for Euro 4 emissions standards.

The SCR system also uses the claimed first ever application of isothermic canning of fully-extruded substrates. In addition, the supplier has applied its experience in advanced acoustics engineering and catalytic converter canning technology to overcome space limitations in integrating the acoustic components.

"The SCR technology responds to the commercial vehicle industry's criteria that NOx emission reduction solutions be both environmentally effective and economically viable," said Tenneco chairman Mark Frissora.

"Tenneco Automotive is well-positioned to grow in the commercial vehicle market with the addition of emission control content to our existing ride control and elastomer products for this sector," added Frissora. "The [Mercedes-Benz] Actros [truck line] business reflects the market share growth we expect to see as a result of establishing a new business unit dedicated to the commercial and specialty vehicle markets."

SCR technology has been shown to reduce nitrogen oxides (NOx) emissions in diesel engines, making them compliant with the strict Euro 4 emissions limits well in advance of the October 2006 deadline for compliance.

The system works by injecting precise quantities of urea solution into the exhaust gases where it is converted to ammonia. The ammonia then converts noxious nitrogen oxides to harmless nitrogen and water vapour.

DaimlerChrysler has already announced plans to use SCR technology to reach the Euro 5 standards that come into effect in 2009.

The development and engineering for the Actros is being done at Tenneco Automotive's engineering centre in Edenkoben, Germany, and production will take place at its exhaust manufacturing facility in Zwickau, Germany.

Tenneco Automotive specialises in developing and producing advanced exhaust after treatment systems that help vehicle manufacturers meet increasingly stringent emissions regulations. The company was one of the first to manufacture diesel particulate filters for passenger car applications in series production in 2000. Today it produces more than 300,000 units annually.