Two months on from new London Low Emission Zone (LEZ) rules coming into force, attention is now focused on making sure thousands of low emission vehicles continue reducing pollution.

Despite the large number of vehicles affected by the London LEZ, compliance rates are high. 98% of trucks and 96% of buses and coaches are now meeting the new rules, with many vehicle operators choosing to retrofit emissions technology to meet these new requirements.

TfL approved retrofit options are based on diesel particulate filter technology. The specialist filters used in these systems need regular maintenance to maintain their low emissions and therefore their LEZ compliance.

Kathye Henderson from Eminox outlines why maintenance of these filters is so important.

Full flow diesel particulate filter(DPF) systems trap particulate matter, and need a way of getting rid of the trapped matter so they don't become blocked. The systems are designed to regenerate during normal operation. However, incombustible residues and soot can accumulate inside the filter, so the filter needs periodic servicing to remove any build up. If filters become blocked this can lead to an increase in fuel consumption, and ultimately to permanent filter damage that would require replacement.

Eminox systems, including the CRT (Continuously Regenerating Trap), are supplied with indicators to give an early warning of any build up in the filter. Checking the system's warning lights is essential as the length of time a filter can run between services is variable.

Filters can be reconditioned and reused, thanks to specialist filter cleaning technology - Eminox uses the patented Xpurge system which uses a combination of water and compressed air. This method removes accumulated particles from deep within the filter structure and is proven to be more effective than conventional cleaning methods which can involve lengthy oven baking.

“After more than 15 years of producing diesel particulate filter systems, we've tried most methods of cleaning the filters, so we know how difficult it can be to get the filters as good as new,” says Henderson.

Advanced Xpurge cleaning is offered in conjunction with the patented Veritex inspection technology - this gives a picture of the internal condition and allows vehicle operators to be confident it has been comprehensively cleaned - not just on the visible surfaces, but throughout.

Getting filters back to 'as new' levels of performance is more cost-effective in the long term and means longer intervals between services. Eminox reconditioned filters also come with a 12 month guarantee. The Eminox range of filter servicing packages includes 'while-you wait' filter servicing, self-exchange and full service on-site exchange. A full system check is offered prior to the annual VOSA test, which is essential for the vehicle to continue being used in London without LEZ charges.

The company's three UK branches have specialist technicians to provide service and support including system checks, data logging, ESI downloading, diagnostics, catalyst testing and catalyst recovery.