Diesel engines produce soot, which is made up of tiny particles, and these particles can be harmful to human health
and the environment if not properly filtered.
A Diesel Particulate Filter (DPF) is a device designed to remove particulate matter (PM) or soot from the exhaust gas
of a diesel engine. The primary function of the DPF is to reduce particulate emissions and meet environmental
regulations for air quality.
DPF (Diesel Particulate Filter) regeneration is a process used in diesel engines to burn off accumulated soot
(particulate matter) from the DPF to prevent clogging. This is critical for maintaining engine performance, fuel
efficiency, and reducing emissions.
- Passive Regeneration: It Occurs automatically when the exhaust temperature is high enough (usually
at highway speeds). The heat in the exhaust gases is sufficient to burn off the soot particles in the DPF. This
process doesn't require any additional intervention from the vehicle's engine management system.
- Active Regeneration:It is initiated when the soot level in the DPF reaches a threshold that passive
regeneration cannot handle. The vehicle's engine control unit (ECU) increases the exhaust temperature by injecting
extra fuel into the combustion process or using other methods, such as post-injection or exhaust gas heating. This
process burns off the soot in the filter and reduces the risk of clogging. Active regeneration usually occurs during
city driving or conditions where passive regeneration is insufficient.
A Catalyzed Diesel Particulate Filter (DPF) is a type of DPF that has a catalyst integrated into the filter
structure. This catalyst helps in the oxidation of soot (particulate matter) and other harmful emissions in the
exhaust gases from a diesel engine and supports passive regeneration of DPF.
The catalyzed DPF has an additional catalytic coating, typically made of platinum, palladium, and rhodium, on the filter
material (often ceramic). This catalyst lowers the temperature at which soot burns, facilitating the regeneration
(self-cleaning) of the filter. By combining the filtration capabilities of a DPF with the catalytic properties of a
catalyst, a catalyzed DPF ensures better control of particulate emissions and is often used in modern diesel engines to
comply with stricter environmental regulations.