Engine Operation 18 UENR0623-02 Illustration 15 g03343187 A typical example of a CEM with a wall flow Diesel Particulate Filter (DPF) For engines with a power rating of 55 kW or higher, a wall flow Diesel Particulate Filter (DPF) is used. Illustration 16 g03343192 A typical example of a CEM with a through flow Diesel Particulate Filter (DPF) For engines with a power rating of 55 kW or lower, a through flow Diesel Particulate Filter (DPF) is used.