What Is DPF?
The Rolling Rig
Keep a worry-free truck with these maintenance tips!
You’ve probably heard that diesel fuel ”burns clean” — and for that, you can thank your truck’s DPF filter. So, what does DPF stand for and what is a DPF filter designed to do? A Diesel Particulate Filter reduces harmful emissions from your Freightliner or International semi-truck by capturing soot particles and removing them from the exhaust.
What Is a DPF Filter?
After being expelled from the engine, exhaust gases are directed to the DPF system. The DPF filter traps soot particles, stores them, and then burns off the excess soot in a process called “regeneration.” Regeneration converts the soot into carbon dioxide, preventing harmful emissions.
DPF System Regeneration
Regeneration works by raising the exhaust temperature high enough so that the excess soot burns off. When the filter is clogged with soot, the DPF system can automatically regenerate itself while you drive. This may happen in one of two ways:
- Passive Regeneration – On long runs between and , the engine temperature can get high enough for soot to burn off on its own. Passive regeneration occurs when you maintain a steady highway speed for a period of about 45 minutes.
- Active Regeneration – If you do mainly short runs around , you may not be on the road long enough for passive regeneration to kick in. In this case, the DPF system will inject excess fuel to raise the exhaust temperature and trigger active regeneration.
Signs of a Blocked DPF Filter
If you tend to drive for shorter periods, passive regeneration may not work. In this case, the DPF system will automatically begin active regeneration when the computer detects that the filter is becoming clogged with soot. A dashboard warning light will flash if your filter is blocked and requires regeneration, and you may notice the following signs for the next 10 to 15 minutes while regeneration is underway:
- Acrid exhaust smell
- Cooling fans engaged
- Change in engine sound
- Slightly reduced efficiency
- Deactivation of automatic stop/start
If the warning light is still on after DPF system regeneration, you may need to schedule service for a process called forced regeneration. This will usually remove enough excess soot to restore the DPF system’s ability to automatically regenerate. It’s also important to periodically remove the DPF filter and clean it in a compressed air machine to remove excess ash from regeneration burn-off.
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Questions about what DPF filter is designed for your truck? The team at International Used Truck Center is here to help with any questions you may have about diesel engine maintenance. Contact us for more info!