Particle Filter Regeneration for passenger cars

 

In order to avoid filter damages or a detoration in consumption through excessive exhaust back pressure, the DPF has to be regenerated when reaching a critical soot load.

The soot load in the DPF is monitored by the direct measurement of the exhaust back pressure using pressure sensors.

For the DPF regeneration, the exhaust gas temperature is increased to at least 620°C by motor measures (post-injection), which results in the soot burning with oxygen. When using a fuel additive, an exhaust temperature of approximately 450°C is sufficient for the combustion of the soot.

 

Especially when using biofuels, the post-injection of fuel to increase temperature can lead to dilution of the lubricating oil, and consequently to engine damage. 

An improvement in this situation is the direct injection of hydrocarbons (diesel fuel) into the exhaust system. The fuel is catalytically burnt in the downstream oxidation catalyst and supplies the heat required for the DPF regeneration. In line with our customers' wishes, we have developed HC injectors and fuel vaporizers that are close to the serial introduction.