The DPF regeneration process creates very high exhaust gas temperatures and the exhaust will radiate a considerable amount of heat during and after DPF regeneration, and after you have switched the engine off. This is a potential fire hazard.
Regeneration, or regen, of the DPF filter, is the process that burns the soot accumulation that is inside the DPF filter. If you can no longer start a regen then you will eventually get stuck in a derate which will then lead to an engine shut down.
DPF System
PM continues to accumulate and manual regeneration is required to ensure normal operation of DPF. By driving continuously (for example, at around 60 km/h. for 20 to 30 minutes. By avoiding short trips, or by driving continuously (leaving the engine running for long periods of time).
However, due to the nature of city traffic, the regeneration process can be interrupted when the vehicle completes its short journey and is turned off. If this occurs, the ECU is programmed to recommence the process when the engine is restarted and back up to temperature again.
How long does the regeneration take? The DPF regeneration cycle takes approximately an hour and a half (1 1/2 hours) to complete and can be completed as part of a routine service.
If your forced DPF regen lasts closer to an hour or continues beyond that, it likely suggests that your exhaust temperatures are not building up high enough to successfully burn off the soot collected in the DPF and that the truck is still trying to bring down those soot levels.
Monitor the Exhaust temperature and RPM. When the idle comes back down it means that the regen has finished. If the regen starts and stops then you may have a problem that prevents the regen from taking place.
All you have to do is get your car on an A road or motorway on a regular basis, such as every 300 miles. You then need to run it for 10-20 minutes at speeds in excess of 40mph. This will heat up your exhaust and burn off any soot in the filter.
You should consult the handbook for your vehicle for more specific guidance on how you should drive to initiate regeneration of the DPF and clear the warning light. Nevertheless, a general rule of thumb to follow is that you should run the engine at least 40 mph and at least 2500 rpm.
The easiest and cheapest method of DPF filter cleaning is by driving the vehicle for a long-distance at high revs per minute. Doing this increases the heat of the exhaust and burns the soot blocking the DPF filter. It's best to drive on a motorway or A road where you can keep the vehicle at a consistent speed.
So it is advised that drivers regularly give their diesel vehicle a good 30 to 50 minute run at sustained speed on a motorway or A-road to help clear the filter.
Thermal regeneration of diesel particulate filters requires temperatures of around 600°C (Figure 1). Such exhaust temperatures are rarely encountered in practical applications of the diesel engine. Most heavy-duty diesel engines produce exhaust temperatures in the range of 300-450°C.
How Often Does DPF Regeneration Occur? Active regeneration happens roughly every 300 miles and is triggered by your car's electronic control unit (ECU) once your soot level is approaching 40 to 45%. Passive regeneration should occur when you take your car on longer journeys at higher speeds.
Force regeneration of the particulate filter
The ash from the engine oil accumulates on the inner walls of the ceramic and in the pores. This increases the pressures in the DPF and if clogged, can even damage the engine.
Active DPF regenerations need to burn extra fuel to achieve the high exhaust temperature for soot oxidation, which results in the increased fuel consumption rates.
In many cases, a proper DPF delete will result in gaining over 100 horsepower while improving your fuel mileage and the lifetime of your vehicle.
A DPF can last up to around 100,000 miles if maintained properly. After the car has exceeded that mileage, you could be looking at paying a large amount of money for a replacement – so always properly check MoT and service records when buying a used car.
Level four: The DPF warning light flashes and the stop engine light comes on. This means the soot level in the DPF is full. Engine power will de-rate — by as much as 40 percent — and begin a shutdown sequence.
The DPF will not regenerate if:
The engine management light is on for any fault; There is a faulty EGR valve; There is less than 20 litres of fuel in the fuel tank, if the fuel light is on or the engine management light is illuminated.
The vehicle needs to run at operating temperature during the regeneration, so highway driving is best. Just drive as you normally would. During active regeneration, the exhaust outlet temperature is extremely high. So watch your location if regeneration is about to begin.
A forced regen occurs when soot builds up inside the diesel particulate filter (DPF) to the point that the vehicle is no longer operable. When this happens, a driver has to pull over and initiate a self-cleaning process that can take up to 40 minutes — valuable time that could have been spent on the road.
On average, it takes between thirty and sixty minutes to complete a forced regeneration. The substantial heat required for the regen renders the engine and aftertreatment system untouchable until it has time to cool down.
Parked/Stationary regeneration is used when the Passive, Assist and Reset regenerations do not adequately reduce the soot in the soot filter. This process requires the operator or technician to start a Parked regeneration within the InfoCenter's Service menu (it typically takes about 30 minutes).