Diesel engines burn fuel differently to petrol engines. As a result, the engine produces a lot of soot as part of the combustion process, that can cause significant health issues as well as damage the environment. In 2009, Diesel car manufacturers began fitting “Diesel Particle Filters” or “DPFs” to all diesel cars as a way of reducing toxic particle emissions from their exhausts. The idea was for the DPF to trap the fine, practically invisible vapour and then eliminate them by exposing the resulting substance to high temperatures producing harmless ash.  This process is known as DPF regeneration. There are two known kinds of DPF regeneration. “Passive regeneration” and “active regeneration”. The former occurs when the driver reaches speeds above 40mph for several minutes at a time. When this happens regularly, the DPF burns the particulates inside the DPF automatically. It is efficient over long distances but those that drive typically in and around towns and cities,