GPF gasoline engine particulate trap

GPF (Gasoline Particulate Filter) is a particulate filter designed specifically for gasoline engines. It is developed based on the circulating three-way catalyst, with a cylindrical shape, and is an efficient ceramic filter. Its function is to further capture and reduce particulate matter in gasoline engine emissions to meet the National VI emission standards.

The core technology of GPF gasoline engine particulate trap lies in wall flow honeycomb ceramics. This ceramic carrier is densely packed with numerous parallel axial honeycomb channels inside, and there is a special unidirectional open state between adjacent channels: one channel only has an inlet, while the other only has an outlet. When the engine exhaust flows into the open inlet port, it will pass through the porous wall of the GPF carrier and be discharged through adjacent ports. During this process, particulate matter will be firmly captured on the walls and inside of the carrier through various means such as interception, collision, diffusion, and gravitational settling, ensuring that particulate emissions are effectively captured before entering the atmosphere.

GPF regeneration

As the mileage of the vehicle increases, the accumulation of particulate matter in the GPF will gradually increase, leading to an increase in engine backpressure and affecting engine performance. Therefore, it is necessary to regularly clean GPF to restore its filtering function. This process is called GPF regeneration, which is mainly achieved by promoting the oxidation combustion reaction of carbon particles inside GPF.

The regeneration strategy of GPF includes two methods: passive regeneration and active regeneration. Passive regeneration is usually achieved in daily driving. When the driver releases the accelerator pedal, the engine enters a fuel cut-off state, introducing a large amount of oxygen and promoting the oxidation and combustion of carbon particles in the GPF. When passive regeneration is insufficient to meet the demand, an active regeneration strategy needs to be adopted. This usually involves the vehicle operating under specific conditions, such as driving on a highway at a speed of 80 kilometers per hour for 30 minutes, adjusting the ignition angle and air-fuel ratio through commands from the engine control system (ECM) to increase the temperature inside the GPF, thereby promoting the oxidation combustion of carbon particles.

It is worth noting that the GPF regeneration process cannot remove certain ash substances (such as CaO, P2O5, ZnO, SO3, and Fe2O3). After these ash substances accumulate over time and fill the GPF, a new GPF will need to be replaced. In addition, the Diesel Particulate Filter (DPF) is widely used in diesel engines to capture and filter particulate emissions before they enter the atmosphere.