DPF regeneration and why diesel may be detrimental to short distance travel

DPF can initiate regeneration in several ways, but all require exhaust gas to reach a very high heat level - typically around 500 degrees Celsius, which is twice that of a household oven. When you drive the car at a speed of 40 miles per hour for a few minutes, "passive regeneration" occurs, and regularly performing this operation should automatically eliminate particles in the DPF.

However, many drivers who live in towns or only drive short distances do not raise their exhaust temperatures high enough for 'passive updates' to occur. This may lead to the accumulation of soot, ultimately blocking the DPF and causing engine problems such as reduced fuel efficiency and misfire. Warning lights may also appear on the dashboard. If driving at high speeds is not frequent, the engine will attempt to clear the DPF through "active regeneration". This is where the engine makes the exhaust gas hot enough to burn soot without the need for the car to run at high speeds.

Unfortunately, active regeneration only occurs when the car is in motion, so urban drivers who typically drive while parked may find their car unable to actively regenerate the DPF. Most cars have a two-level warning system. If you see amber lights, you should be able to allow the DPF to regenerate on its own by driving at a speed of 40 miles per hour for about 10 minutes. However, if you see a red DPF warning light, it means you need to go to the garage.