How Does DPF Work in Trucks


Rudolf Diesel's 1893 patent on his engine design

Image via Wikipedia

We were asked How does DPF work in trucks?  It is a relatively simple process. It is the removal of the particles from the exhaust that are produced when a fossil fuel is burned in an internal combustion engine. What makes this process more complicated is to successfully remove the particles without the performance of the diesel engine being adversely affected.

The flow of gases needs not to be impeded while at the same time the removal of the particles in the gases needs to be accomplished. This is so the diesel engine will be allowed to perform its primary function of producing sufficient power that is required from it to accomplish its purpose. In most cases this is the turning of wheels on tractor trailers and other big trucks.

This removal of particles is now being done with a system of chambers in the diesel particle filters. The chambers inside a canister allow for an increase in the surface area the gases come in direct contact with.  The greater the contact area is the more the particles will cling to it and thus be removed for the gases before it leaves the chamber. For those that want to see this process visually, look at the tailpipe of an old diesel powered truck. The soot deposit that is present is this principal in action.

The next obstacle for manufactures of DPF’s to overcome was to remove the particles from these chambers so a buildup would not impede the flow of the exhaust gases out to the remaining part of the exhaust system. At first disposable DPF’s were used. This removed the particles from building up, but does require periodic maintenance to be performed on a regular basis. It is also costly to replace these filters to keep the diesel engines operating at peak efficiency.

The development of the passive regenerative DPF was the cost effective alternative. By coating the inside of the DPF with a platinum catalyst and then placing it directly aft of the exhaust manifold.  The heat and catalyst provided the proper environment for the chemical process of destroying the particles that were removed from the gases. This allowed them to break down into non-hazardous molecules.

This process does require some maintenance to clean out the non-hazardous particles, but is significantly reduced over the disposable DPF. During normal operations, the passive regenerative DPF only needs to be cleaned out of particles once every 6 months. It also does not need to be replaced, just cleaned and reinstalled.

With the knowledge of how does DPF work in trucks becoming more widespread, their use is growing. This is good for the environment and the people that have to breathe the air surrounding the diesel powered trucks while they are operating.

The following video shows how a DPF works as well as how fleet owners can get the jump on regulations regarding EPA emissions.

 

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