DPF regeneration (active) Some cars don't use the motorway often enough. When the accumulating soot reaches about 45%, the DPF switches to active regeneration. The car forces higher exhaust temperatures, burning the soot in the process.
Soot Load Percent and Regen Cycles
The engine controller reports the DPF soot load as a value from 0% to 250% — not 0% to 100% as you may expect. The value may fluctuate, and this is normal.
You will know whether active regeneration is taking place by the following symptoms: Engine note change. Cooling fans running.
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.
To make sure that the regeneration takes place, most manufacturers suggest that every few hundred miles, the car is driven for a period of more than 15 minutes at a consistent speed of more than 40mph. Doing this should kick-start regeneration and clear the filter.
A forced regeneration can be performed by any service shop with the appropriate diagnostic software. The cost for a forced regeneration varies. Generally, it is between $300-$700 depending on the technician's required diagnostic time and the length of time your DPF regeneration lasts.
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.
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.
Active regeneration will be initiated every 300 miles or so depending on how you use your car and will take 5 to 10 minutes to complete. But it's a problem if your journey's too short and the regeneration doesn't finish.
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.
An active regen cycle is a normal process that takes place as the truck is going down the road. A computer sensor monitors the DPF and a dashboard indicator light notifies the driver that the regen is taking place, or the DPF is now cleaning. “You'll notice a reduction in power during a regen,” notes Nace.
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.
If this happens, just carry on driving, keeping your engine speed above 2,000 revolutions per minute and shifting down if necessary. The filter-cleaning process will start - and we recommend you don't stop the journey or switch off the engine until it's finished.
The multimeter should (typically) display a voltage between 4.5 to 5 volts for the 5-volt reference, a steady 0 volts for the ground wire, and between 0.5 and 4.5 volts for the signal wire.
DPF BENEFITS
Better fuel economy: Fuel economy is a big winner after deleting the DPF. Not only will a vehicle conserve the fuel that is utilized by the filter for regenerative purposes, but a cleaner running engine is also an engine that runs more efficiently.
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.
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 car has an automatic transmission, shift your gears in a manual mode by moving the gear shift gently. No need to use the speed limiter, it is with no seeming value added. Ride like this for a minimum of 30 minutes. This will initiate a regeneration cycle, and your DPF will be cleaned.
Technically yes, but we would not recommend it. If you ignore the DPF light and continue driving, the build-up of soot will soon reach a point whereby your car has to enter 'limp-home' mode in order to prevent any damage to the engine.
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.
Most DPFs will automatically clear as they're used but on rare occasions, in specific circumstances, they may get blocked and require manual cleaning. In normal use, a DPF cleans or regenerates itself by reaching a sufficient temperature to burn off the excess soot.
During normal working condition the diesel particle filter will clean itself regularly by self-regeneration. After each regeneration-cycle, some ash are left in the filter and cause shorter regeneration interval. This means that each DPF will need service sooner or later.
How long does a parked DPF regen take? It takes approximately 20-60+ minutes. It will continue to regen until the soot level has reached 'low' or '0%. ' Some trucks will let you monitor your soot level gauge on the dashboard.