Semi-passive DPF

The SMF-AR, supplied by Mann & Hummel via Cawdell for retrofit applications, is suitable for use on a wide range of vehicles and equipment. It is not as temperature dependant as many passive filters due to the combination of an in-built heater system and a passive fuel additive system.

A sintered metal filter material is used to separate and trap particles from the exhaust stream whilst the automated fuel additive dosing system reduces gaseous emissions and ensures complete oxidation of the trapped particles, therefore continuously “regenerating” under normal operating conditions of the engine.

In situations of low exhaust temperature the electrical heater elements will automatically elevate the temperature of the metal filter and cause regeneration. The engine can continue to be operated during the electrical regeneration. The fuel additive dosing and the standby heaters are controlled by a programmable ECU which is set up during installation of the system.

The filter achieves up to 95% particulate reduction with extremely low back-pressure.

As with all diesel particulate filters (DPF’s) it is necessary to remove inert ash after lengthy intervals. The SMF-AR has a larger ash storage capacity than similar sized ceramic filters therefore the intervals between cleaning are longer. Cleaning of the filter is simply performed by removing the filter module and washing with pressure washer.

Cawdell Ltd supply and install the SMF-AR

SMF and SMF-AR are registered trade marks of Mann & Hummel. Cutaway image courtesy of Mann & Hummel.