Technology & how it works
With its unique design and materials, the City-
Filter
® offers major advantages over conventional particulate reduction systems. The robust design, extreme heat resistance and very high soot-
holding capacity provide the ideal basis for retrofitting diesel vehicles. The HJS City-
Filter
® is maintenance-
free and will last for the lifetime of the vehicle. It requires neither sensors, electronics nor additives.
The City-Filter® has been tested in Germany by TÜV and has the national type approval required under EU regulations. The filter is available for an array of different vehicle models such as the Mercedes Benz-Sprinter, Ford Transit, Fiat Duacto, Iveco Daily and many more.
HOW THE FILTER WORKS
The hot exhaust gases from the engine – which contain soot particles – are fed into the filter housing and through the sintered metal filter (SMF
®) developed by HJS. The gaseous components flow through the microscopic pores of the filter pockets; the soot particles, including the ultra-
fine particles, are trapped on the surface and deposited on the individual filter pockets.
FILTER REGENERATION
Regeneration (cleaning) of the filter starts when the exhaust gas temperature reaches roughly 200°C. The nitrogen dioxide (NO2) formed with the help of the oxidation catalytic converter (oxi-
cat) comes into contact with the soot deposited on the filter pockets, causing the soot particles to oxidise and degrade; the NO2 is then reduced to nitrogen oxide (NO). This chemical process is repeated continuously so that the HJS City-
Filter
® regenerates itself continuously, requiring no additional regeneration aids, such as assistance from the engine management system.
COMBI SYSTEM
The HJS City-
Filter
® combi system consists of an integral oxidation catalytic converter (oxi-
cat) or has a highly efficient catalytic coating, and ensures optimum regeneration when the necessary exhaust gas temperature is reached.
The combi filter or so called combi package helps vehicle owners save money when retrofitting a particulate filter as most light duty trucks don’t come equipped with the necessary oxidation catalyst. With HJS combi systems, a new oxi-cat or the catalytic coating of the filter itself is included in the price.
