VAUXHALL will reveal a new state-of-the-art diesel engine at next month's Frankfurt Motor Show, combining common rail technology with a maintenance-free particulate filter (DPF).

The DPF system will make its production debut in new 1.9 CDTi versions of the Vectra and Signum early next year.

Exhaust gases pass through the honeycomb-like core where soot particles are collected and burned off at regular intervals.

Instead of using fuel additives for regeneration, like the Peugeot and Citroen particulate filters, the Vauxhall DPF uses a precious metal coating inside the filter.