PSA Peugeot Citroën has developed a new diesel particulate filter with a service life of over 150,000 miles (240,000km), meaning it will effectively be maintenance-free. The claimed breakthrough has come with the use of a new filter medium architecture, called Octosquare (referring to the shape of the filter’s intake channels) and an improved fuel additive.

The first generation of particulate filters required servicing every 50,000 miles but in November last year PSA Peugeot Citroën introduced a new system that used a special fuel additive called Eolys, giving it the ability to go 75,000 miles without a service.

A more efficient second generation Eolys additive, together with a filter with larger diameter and specially shaped intake channels, gives the latest system significantly increased capacity for storing particulate matter, which is then burnt off by a post injection combustion process during normal driving.

The first Octosquare filters will be available in 2004 on top-range Peugeot and Citroën models.

The announcement came as PSA Peugeot Citroën passed a major milestone, selling its 500,000th particulate filter since it first unveiled the technology in April 1999. The claimed world’s first diesel particulate filter appeared on the Peugeot 607 2.2 litre HDi in May 2000, followed by models within the Peugeot 406, 307 and 807 and the Citroën C5 and C8 ranges.

Peugeot and Citroën currently offer six vehicle families with the particulate filter system: Peugeot 406, 406 Coupe, 607 and 807, and Citroën C5 and C8 but this will increase to 11 in the next two years, when a million particulate filter-equipped diesels will have been built.