25 September 2006
At a press event held at its Tochigi technical center north of Tokyo, Honda announced plans to launch a diesel car in the US market by 2009. The car, probably a Honda Accord, would be Tier 2 Bin 5 emission compliant, thus qualifying for sale in all 50 states.
The new engine—based on the 2.2 liter turbodiesel currently sold in Europe—will be fitted with a new NOx reduction catalyst, which combines a NOx adsorber catalyst (NAC) with an SCR catalyst. The catalyst has a two-layer structure, said Honda. One layer adsorbs NOx and generates ammonia during the regeneration of the NOx adsorber. The other layer adsorbs the ammonia and uses it for an SCR reaction to further reduce NOx.
The advanced aftertreatment is combined with in-cylinder NOx reduction measures, including an improved efficiency exhaust gas recirculation system and a 2,000-bar common rail injection system. The engine may also use advanced combustion strategies, such as premixed charge compression ignition (PCCI).
A combination of a NOx adsorber with an SCR catalyst was announced earlier by DaimlerChrysler, who will use a NAC + SCR aftertreatment (without urea) in the 2007 Mercedes E320 BlueTec in the North American market. The 2007 E320, however, will have only Tier 2 Bin 8 emissions. To reach the Bin 5 emission level, DaimlerChrysler will probably use urea-based SCR system.