Diesel particulate filter systems explained
DPF stands for diesel particulate filter. These filters are used to reduce the number of hazardous particulates that get into the combustion systems in diesel cars. Its goal will be to create air cleaner and safer particularly in tight. Read on to find out more.
Euro 5 standards
Since 2009 when the “Euro 5′ standard took effect, exhaust emission standards for all new diesel vehicles have effectively required the fitment of a DPF in the exhaust systems. Indeed, a lot of cars which were built before 2009 will come with filters fitted too.
They are also used for a reason because the diesel particulate (soot) emissions can cause serious health problems for humans. DPFs cut down on diesel soot emissions by 80percent, but they’re not for everyone. Even if you’re driving not exclusively urban/stop-start-style, modifications to your driving habits may be necessary in order to keep these systems operating effectively.
How are the diesel particulate filters work?
Diesel Particulate Filters (DPF) collect soot particles to avoid them being emitted from the exhaust. Like any filter, it is essential to empty them frequently to ensure their performance. For a DPF this process is called “regeneration”. Through this process, the collected soot is burned off at high temperatures so that there is only ash.
Regeneration is either active or passive
Passive regeneration
The process of passive regeneration occurs automatically on the motorway if the temperatures of the exhaust are high. As many cars are not driving on motorways very often, manufacturers of vehicles have developed “active” regeneration. In this process, it is the electronic engine controller (ECU) that controls the process.
Active regeneration
When the filter has been filled with soot and exceeds the set amount (about 40%) it is possible that the ECU will initiate post combustion fuel injection, which will increase the exhaust temperature and trigger regeneration. If the motor is shut off while the regeneration is underway, it could not be finished, and the warning indicator will come on to signal that the filter is blocked partially.
It should be possible to complete a regeneration cycle and then clear the warning light by driving while increasing the temperature.
Effects of active regenerative
During active regeneration, you might be able to observe the following signs:
- Cooling fans running
- Increased idle speed
- The automatic Stop/Start feature is disabled.
- A small increase in the amount of fuel consumed
- A strong, spicy smell emanated from the exhaust.
- Engine note change
If the regeneration is unsuccessful because of a lack of motorcycle, any extra fuel injected into the cylinders won’t burn, and it will be drained in the sump. Therefore, the quality of the oil is deteriorating and the level of oil will increase. A majority of DPF-equipped cars will have an oil quality/viscosity gauge, however, it is crucial to ensure that the oil level is not higher than the limit of the dipstick. Diesel engines are able to run on their own oil if there is a high level – often to the point of destruction.
If you ignore the diesel particulate filter warning light and drive with a comparatively slow stop-and-start style, soot will increase until it reaches 75%. At that point, you can expect to see additional dashboard warning lights turn on. At this point, driving at a high speed will not be enough to completely clear the filter. You’ll be required to bring the vehicle to a dealership to get “forced” regeneration.
Forced regeneration
Regeneration by force is mandatory when “active” regeneration criteria have not been met and the soot levels within the DPF are now at around 70 percent. If not addressed, the loading of soot will continue to increase. At this level, a diagnostic tool must be utilized to initiate regeneration. At around 85% loading, regeneration can no longer be done on the vehicle. In this case, you will need to get rid of all DPF to be replaced or cleaned.