DPF (Diesel Particulate Filter) regeneration is the process of burning off accumulated soot from the DPF to restore exhaust flow. Active regeneration injects extra fuel to raise exhaust temperatures to 1,000°F+, burning the soot. Frequent regens reduce fuel economy and cause downtime. Combustion catalyst additives like Fuel Ox reduce soot production at the source, extending intervals between regenerations and improving fleet uptime.