What Is A Diesel Particulate Filter?
Diesel Particulate Filters, or DPFs, reduce diesel vehicles' exhaust emissions and ensure that the vehicles are compliant with European legislation. DPFs dramatically reduce the number of particles emitted from diesel engines by using a simple filter system. They trap approximately 85% of the soot produced during diesel combustion rather than releasing the pollution into the atmosphere.
Particulate Filters Must Regenerate
Like with any other filter system, the filters must be cleared to continue working effectively. This process is known as regeneration and occurs when the filter reaches a sufficiently high temperature, converting the soot to a much smaller quantity of ash.
For most systems, regular use of the engine at a sufficient speed will result in a high enough temperature of the exhaust gas to trigger regeneration. These high temperatures may result in a slight smell during regeneration, particularly during the first cycle.
To automatically regenerate the filter, you must drive a vehicle at 50mph or above for at least 20 minutes. However, this may vary from manufacturer to manufacturer.
What If It Doesn’t Regenerate?
Usually, you can resolve the problem by driving the vehicle to trigger the regeneration process; each vehicle handbook will have specific guidelines for doing this. If you cannot drive the vehicle to begin the regeneration process, the filter will become blocked. Not initiating the regeneration process will result in damage to the filter and will reduce overall vehicle performance. If the filter does experience a build-up of soot, a warning light in the vehicle will alert the driver.
Suppose it is not viable to drive the vehicle in a way that clears the filter - e.g. due to traffic conditions or speed limits. In that case, you can take the vehicle to a dealership for forced regeneration.
Any damage to the vehicle that occurs due to failure to follow the regeneration process will not be covered by the manufacturer warranty package or the funder's maintenance agreement.
Will These Vehicles Be Suitable For You?
Drivers operating in urban environments may not be best suited for vehicles fitted with a DPF. Driving in these environments may not allow the vehicle to trigger the automatic regeneration process. Therefore, it's hard to recommend cars with diesel particulate filters for those going less than 5,000 miles per annum or those driving in urban only driving conditions.
Alternatives For Urban Drivers
Most manufacturers fit their diesel vehicles with a diesel particulate filter that requires a high-speed drive cycle to regenerate. However, some manufacturers equip their vehicles with a self-heating particulate filter. Some will inject fuel straight into the filter, which burns and increases the filter's temperature. Others have heaters built into the filter.
Alternatively, petrol, petrol hybrid, or electric vehicle may be more suitable for a driver operating only in urban areas. All drivers must ensure that their desired vehicle is fitted with suitable and appropriate technology for their driving conditions and requirements. For example, suppose a vehicle with a diesel particulate filter is selected. Then the driver must follow the manufacturer recommended DPF regeneration program.