The refurbishment of diesel particulate filters, particularly of sintered metal and ceramic filters, can be a delicate issue, because simply cleaning them out is often not enough. What's more, it's very easy to damage the filter's catalytic coating or even the filter housing itself and so it's essential that the cleaning process is performed with great care while still being thorough and effective. But as we've already said, DPF® refurbishing "Made by HJS" is more than just cleaning. By employing the best possible methodology, extensive incoming and final inspections (including the taking of photos to document filters' condition) and state-of-the-art equipment for testing filtration performance and catalytic functionality*, HJS has developed an exacting procedure that guarantees complete and proper refurbishment.
If the catalytic coating is intact, nitrogen monoxide (NO) is converted to nitrogen dioxide (NO2). Nitrogen dioxide (NO2) is required for continuous regeneration of particulate matter (CRT® principle). The filter, therefore, essentially traps only particulate matter that cannot be regenerated.
If the catalytic coating is damaged, an inadequate volume of nitrogen monoxide (NO) is converted to nitrogen dioxide (NO2) and the soot particles in the filter are not degraded. The filter, therefore, traps not only particulate matter that cannot be regenerated, but soot particles, too. This means that the exhaust backpressure increases again quickly!