Demystifying the DPF (Diesel Particulate Filter)

It’s hard to turn on the news these days without hearing about rising pollution, and it seems as though diesel is always the villain of the piece due to the high level of emissions which come from diesel vehicles.

The government turning around from telling us diesel was the cleanest source of fuel to the very worst pollutant on the roads has hit haulage companies hard, but there is a way you can keep your fleet of trucks, vans or lorries without falling foul of new laws and punitive tariffs. This is where the Diesel Particulate Filter (DPF) comes in.

All vehicles manufactured after 2009 will have a DPF as standard, but if your vehicle or fleet is older than this, there are definite benefits in having a DPF professionally fitted:

• Firstly because it will enable your vehicles to attain a Reduced Pollution Certificate (RPC) which will entitle you to a discount on your Road Fund Licence
• Secondly because any haulage companies planning to send drivers inside the M25 (the London Low Emissions Zone) will be charged an extortionate daily rate unless they can prove they have a DPF fitted

What is a Diesel Particulate Filter?

The filter is used to trap the soot produced by diesel engines so that it cannot escape into the atmosphere. These filters allow vehicles with a previously poor emissions record (as low as Euro 0) to reach current UK standards. The problem is that the filter can become blocked after prolonged usage so DPF regeneration – how the filter is cleaned ­– becomes a key issue.

Active or Passive Filters

Passive filtering involves the vehicle being driven at around 40mph for about 15 minutes or being driven for a longer time without stopping. The filtering system is cleaned by reaching a certain temperature which burns off any clogging soot.

The trouble with passive systems is that haulage companies which specialise in city deliveries or whose drivers make regular stops don’t allow their engines to reach this heat, and therefore the filter can become blocked.

There are several ways to improve these systems for city or short journey use:

• Continuously regenerating traps – these include ceramic filters with a catalyst at the front which allows the soot to burn off at lower temperatures
• Catalysed Continuously Regenerating Trap – This brings the temperature that the pollutants will burn at even lower by coating the filter with the catalyst
• Fuel Borne Catalyst – This is an additive which you add to the fuel system which reduces the amount of soot produced and ensures that the soot which enters the filter is already catalysed

The other option is an active system, where a company specialising in DPFs will take the filter off and clean it. They will then either exchange it so that you can continue driving or you will have to wait while they send it off to a heating unit which will burn off the soot build-up.

DPF Companies to Consider

There are a number of companies offering differing filtering solutions to haulage companies looking to upgrade their diesel fleets. Here are some to consider with their contact telephone numbers:

Astra Vehicle Technologies -0151 348 5777

Caswdell Group - 01332 755477

Clean Diesel Technologies - 01342 894 590

Cybrand - 0844 880 9830

Dinex - 01925 849 849

Eminox - 01427 810888

Huss - 0208 462 0463

Pirelli - +39 02 938746000

It is important to make sure your vehicles reach current UK standards throughout the country, but it is also important to make sure that your diesel vehicles are able to run for a long, healthy time. The right DPF could be the solution to both problems.

Norman Dulwich is a Correspondent for Haulage Exchange, the leading online trade network for the road transport industry. Connecting professionals across the UK and Europe through their website, Haulage Exchange provides services for matching haulage companies with jobs in road transport and haulage work. Over 4,000 transport exchange businesses are networked together through their website, trading jobs and capacity in a safe 'wholesale' environment.

Writer and Online Marketing Manager in London.