A diesel particulate filter (DPF or) is a device designed to remove soot particles released by burning or exhaust of a diesel engine.
Gas emission standards for new cars required to effectively mount a particle filter in the exhaust of diesel engines since 2009, when the standard “Euro 5”, entered force. In fact, more cars registered before 2009 had already mounted particulate filter, pending modification standards.
Operating mode particulate filter
This particulate filter eliminates harmful particles, usually around 85%, but in certain circumstances it can achieve an efficiency of almost 100%. Some filters are disposable, designed to kill and replace once were full of ash accumulated. Alleles are designed to burn off the accumulated particulate catalyst or by using a passive or active means, such as a fuel burner which heats the filter to soot combustion temperature.
This is achieved by programming the motor (when the filter is full) to enter in a manner that raises the exhaust temperature with an injector of supplementary fuel in the exhaust stream that injects the fuel to react with a catalyst to accumulated soot burn and turn to ashes, or other methods.
This mechanism is known as “filter regeneration”.
Cleaning is also required as part of regular maintenance and must be done carefully to avoid damaging the filter. The regeneration process occurs at speeds and speeds higher than can be usually achieved through city streets; vehicles that run exclusively at speeds and low speeds in city traffic may require periodic trips speeds and higher speeds to clean the DPF filter.
If the driver ignores the warning light and waiting too long to speed and speed of the vehicle from those indicated by the manufacturer, DPF cannot regenerate properly, and continued running in this way, it might spoil filter DPF completely, requiring be replaced. Such a new particle filter is extremely expensive, generally priced above 1,500 euros. But there is also the possibility of replacing the particulate filter with one second-hand or aftermarket one, but problems can recur any time.
Some newer diesel engines can also perform what is called a parked regeneration, in this case increases the engine speed to about 1400 RPM while the car is parked, thus increasing exhaust gas temperature.
Variants of DPF filters
Unlike a catalytic converter, which is a continuous flow device, a DPF retaining larger particles in the exhaust gas by forcing it to flow through the filter; However, DPF and DPF does not retain small particles sites without maintenance break larger particles into smaller ones. There are a variety of technologies of particle filters for diesel engines on the market.
Each is designed around some similar requirements:
- Filtered fine
- Minimal pressure drop
- Low Cost
- Suitability for mass production
- Sustainability in time