General Motors has decided to go ahead with plans to rework its 6.6L Duramax diesel V8 engine in anticipation of the new Tier 2 Bin 5 emissions standards that will take effect on January 1st. The new standards call for a 90-percent reduction of oxides of nitrogen and particulate matter. Though the changes won't interrupt production of the Chevy Silverado and GMC Sierra heavy-duty pickups in which the engines are used, they will sharply increase the cost of building the engines. GM Powertrain expects to meet the standards by using a new variable geometry turbo, enhancing the engine's exhaust gas recirculation and using a closed crankcase ventilation system. The exhaust system will also be supplemented with an oxidizing catalytic converter and particulate filter like those first introduced on many European diesels a couple of years ago.

You may remember Ford's plans to meet the new standards, which include using expensive piezo injectors on its new 6.4L twin-turbo Powerstroke diesel. Dodge has not revealed yet how it plans to get the Ram's Cummins diesel up to snuff by January 1st.

[Source: Autoweek]