How it Works - DPFs and GPFs

Diesel Particulate Filters and Gasoline Particulate Filters

Diesel particulate filters (DPFs) and gasoline particulate filters (GPFs) are two types of emission control technologies used in vehicles to reduce the amount of harmful particulate matter released into the air. Both types of filters work by trapping and removing particulates from the exhaust gas of a vehicle, but there are some differences. 

WATCH: Diesel particulate filters cleanse harmful particulate matter from vehicle exhaust.

WATCH: Passenger cars with gasoline direct injection (GDI) engines are increasingly equipped with gasoline particulate filters to remove harmful particulate matter from exhaust gas.

DPFs and GPFs: An Overview

DPFs have been used for years to reduce carbonaceous particulate matter created during the diesel combustion process. They work by trapping and then burning off particulates to limit emissions output. GPFs, on the other hand, are a relatively new technology that are just starting to be adopted in vehicles. Though similar to DPFs in design and function, they are made with different materials that are optimized for the lower temperatures of gasoline engines.

How do DPFs and GPFs Work?

Both DPFs and GPFs are positioned within vehicle exhaust systems. In each case, exhaust gas from the engine combustion chamber flows into the filter and through a porous surface designed to block particles of a certain size from passing through.

Typically, after enough particulates are captured, it leads to a buildup of pressure called "back pressure". At that time, the filter goes through either a passive or active regenerative process to burn off the particulates:

In passive regeneration, if the exhaust temperature is high enough for a long enough period, a catalyst on the surface helps burn off captured particulates.

In active regeneration, excess fuel is typically burned to increase the temperature and burn off the captured particulates.

DPFs and GPFs: Pros and Cons

One of the key advantages of DPFs and GPFs is the fact that they’re highly efficient at removing particulates from the exhaust gas, making them one of the most effective emission control technologies available. However, one of the main drawbacks is that they can become clogged over time, reducing their effectiveness, and necessitating regular maintenance. Certain engine oils, especially those with elevated levels of ash, can worsen the problem. Another thing to consider with GPFs is that they are still relatively new technology. As such, there's limited data available on their long-term performance and effectiveness. Also, the materials used in GPFs are sometimes more expensive than those used in DPFs, which means they may be more expensive to manufacture and install in vehicles. See the related articles below to learn more about how DPFs and GPFs impact vehicle lubrication needs.

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