Diesel Particulate filters can be found on all Diesel vehicles running Euro 5 emission standards, and some vehicle manufacturer’s also installed these in vehicles before the standards were enforced, Two types of system are used, A dry system which uses no fuel additive, and a wet system that does. The wet system additive tank is placed next to the fuel tank, and every time the vehicle is re filled with fuel, the additive is automatically mixed as required. The wet system can be confused with the AdBlue system, which can also be fitted to the exhaust. Please look up AdBlue on this site for a description of operation. If your vehicle is a Mazda with the DPF lamp on please also read the ‘Mazda DPF lamp on’ article on this site.
The diesel particulate filter is mounted in the exhaust system, and looks similar to an exhaust silencer. Its role is to trap exhaust soot deposits so they don’t exit the exhaust. When the filter becomes full of soot, it burns off the soot leaving a much smaller amount of ash trapped in the filter unit, this is called regeneration. There are four ways that the DPF can be regenerated.
1 Passive regeneration takes place at higher road speeds, typically about 60 mph for approximately ten minutes driving, the exhaust temperature is sufficiently high so the process can be completed with little or no intervention from the engine control module.
2 Active regeneration takes place still at the same speeds and driving times as passive regeneration, but it requires the engine management system to modify its fuel injection sequence to create a higher exhaust temperature than normal. this normally used when the filter is more blocked, due to a lack of higher speed driving for a period of time.
3 Forced regeneration takes place only when a diagnostic computer is connected to the vehicle, and the operator has instructed the engine management control module for the process to be carried out. This is normally after other faults in the system have been logged with the control module and the normal regeneration process is unable to take place. Any other faults have to be remedied first, and the forced regeneration can then take place.
4 Off vehicle regeneration takes place only when all the other options have failed and the filter is almost completely blocked with ash or soot. This requires the removal of the DPF and it to be cleaned off the car. If this last process fails, the remedy is to replace the DPF with new.
At R M Motors we have the equipment and the experience to resolve the faults that these systems can cause; whether it be an additive top up and reset, sensor faults, or fitting and calibrating replacement parts.