Diesel Particulate Filter – Hero or Villain? 

Diesel Particulate Filter – Hero or Villain? 

We often come across people who are unaware why DPFs are fitted and comment negatively about how terrible they are, or comment about removing them. I would like to explain the reason why, we as a community need DPFs.

A DPF is fitted to a vehicle to stop carcinogenic (cancer causing) particles from exiting the exhaust and entering lungs. When diesel engine fuel systems used the old “in line” style of fuel delivery, the exhaust particles emitted by the engine were large enough for our body to cough up and remove from our lungs if inhaled. But due to common rail fuel systems, the particles now emitted by diesel engine exhausts are much finer, allowing these particles to enter the blood stream through the lungs and causing health problems.

Diesel engine emissions also contain high levels of NOx (nitrogen oxides – NO and NO2). These emissions cause direct and indirect effects on human health. In addition to impacts on human health, diesel engine emissions directly impact the environment, causing smog, acid rain and deterioration of land and water resources.

Manufacturers are trying to reduce NOx emitted by the engine. To lower NOx, exhaust gas is recirculated back into the engine to lower cylinder temperatures. In effect, this lowers the level of NOx emissions. The downside is that diesel particulate matter is increased. This harmful particulate matter is captured in the DPF, then burnt to harmless ash when the DPF carries out the regeneration process. This process allows modern diesel vehicles to conform to emission laws.

For most people, removing the DPF is not acceptable. We want to prevent our friends and families from getting lung cancer and leave a clean and safe environment for our children to inherit. DPFs have a negative stigma around them due to the cost of replacement. If the DPF system worked more reliably or was cheaper to replace or repair, then perhaps DPFs would be celebrated for their health and environment saving protection abilities, and not demonised due to the financial burden of repair. 

It would show great leadership if manufacturers were doing more to negate the community feeling around DPFs. We understand that the engineers that design these systems are the best in their field and have produced a system that works in most operational situations, but sometimes they fail. In a fair world if a vehicle has a systemic fault with any component then the cost of this component to the consumer should be comparable to the cost of its manufacture. In Australia, in our experience, consumers pay way above acceptable prices for parts in a dealership parts department. We understand that they may not set the parts prices at the dealership, but with the growth of online stores, we can see genuine parts are a lot cheaper overseas. We would prefer to purchase parts from an Australian company but blatant, unnecessary price gouging by Australian dealerships can’t be supported. 

To all those advocates of the removal of DPFs we understand your thinking and can’t help but sympathise in regard to the expense of repair, but the removal of a system that protects you, me and our children from lung cancer is not the solution.

Diesel Particulate Filter – Hero or Villain?