DaveF
11-26-2006, 09:58 AM
Two items of good news per GM:
First, the manual DPF regeneration is done by flipping a switch while driving. Second, dual-wall air gap pipes and insulation keep component surface temps during regeneration comparable to existing gas engine exhaust.
Not so good is the need to periodically have the dealer clean the DPF. Any info on how often (GM helpfully says "eventually") would be appreciated.
From the GM fleet web site (link below):
There are two types of regeneration: 1) Self regeneration,
which is automatic when the exhaust gases are high enough; and 2) Forced regeneration, which is either automatic or manual. In most instances, the regeneration will happen automatically as the truck is driven throughout the day, without involvement by the driver. However,
on medium-duty trucks, if vehicle operation does not produce exhaust gases hot enough for automatic regeneration, a control light will indicate the need for regeneration and the driver may initiate the process by activating a switch on the dashboard. Regeneration requires managing and controlling much hotter exhaust gases than those experienced
on current diesel-powered vehicles. By utilizing dual-wall air gap pipes, insulated catalysts and DPF filters, we are able to retain the heat within
the exhaust system. Consequently, pipe and component exterior skin temperatures are comparable during regeneration with existing gas engine
exhaust systems. Although the DPF filter is designed for long life, eventually the accumulated ash must be removed by special cleaning equipment at truck dealerships.
For this and more info, go to:
http://www.gmfleet.com/gmfleetjsp/us/acquiring/vehicinfo/summaries/2007/Diesel_Flyer.pdf
First, the manual DPF regeneration is done by flipping a switch while driving. Second, dual-wall air gap pipes and insulation keep component surface temps during regeneration comparable to existing gas engine exhaust.
Not so good is the need to periodically have the dealer clean the DPF. Any info on how often (GM helpfully says "eventually") would be appreciated.
From the GM fleet web site (link below):
There are two types of regeneration: 1) Self regeneration,
which is automatic when the exhaust gases are high enough; and 2) Forced regeneration, which is either automatic or manual. In most instances, the regeneration will happen automatically as the truck is driven throughout the day, without involvement by the driver. However,
on medium-duty trucks, if vehicle operation does not produce exhaust gases hot enough for automatic regeneration, a control light will indicate the need for regeneration and the driver may initiate the process by activating a switch on the dashboard. Regeneration requires managing and controlling much hotter exhaust gases than those experienced
on current diesel-powered vehicles. By utilizing dual-wall air gap pipes, insulated catalysts and DPF filters, we are able to retain the heat within
the exhaust system. Consequently, pipe and component exterior skin temperatures are comparable during regeneration with existing gas engine
exhaust systems. Although the DPF filter is designed for long life, eventually the accumulated ash must be removed by special cleaning equipment at truck dealerships.
For this and more info, go to:
http://www.gmfleet.com/gmfleetjsp/us/acquiring/vehicinfo/summaries/2007/Diesel_Flyer.pdf