Evaluation of a Wall Flow Diesel Filter after ≻ 4000 Hours of Use on an Underground Mining Vehicle

A 15″ diameter x 15″ long, EX-47 wall flow diesel exhaust particulate filter, was operated for approximately 5000 hours on a load haul dump vehicle (LHD) in an underground mine. LHD's are an integral part of production in most underground mines and characteristically operate at high power and load conditions for a significant part of their overall duty cycle.

The vehicle was equipped with a Caterpillar 3306 PCTA engine. Fuel containing 0.2 wt% (or less) sulphur and engine oil specified at 0.025% ash were used. Following removal from the vehicle, the filter was analyzed to evaluate physical and thermal properties of the cordierite diesel filter as well as to inspect for ash accumulation or damage. The filter was found to be in excellent physical condition, however ash accumulation was high. The ash was found to be richest in Ca, Zn and P.

This paper provides an overview of various techniques that are useful to characterize diesel particulate filters in assessing their condition after use.