Vibration-Induced Ash Removal From Diesel Particulate Filters

Abstract

Ceramic, honeycomb-type diesel particulate filters (DPF) are commonly used in a wide range of on- and off-road diesel-powered vehicles and equipment to reduce particulate matter (PM) emissions to mandated levels. While the majority of the trapped PM can be removed from the filter through regeneration, incombustible ash builds up in the filter over time. The ash deposits are generally found accumulated in a porous layer along the channel walls, or packed as end-plugs towards the back of the filter channels. Ash accumulation in the filter restricts exhaust flow, reduces the filter’s soot storage capacity, and negatively impacts fuel consumption. In order to mitigate these deleterious impacts on filter operation, the particulate filter is periodically removed for ash cleaning. This study examines the effects of vibrations to remove and dislodge ash deposits from diesel particulate filters, particularly the ash accumulated toward the back of the channels and packed in plugs. Fundamental measurements of ash properties, combined with experiments utilizing full-size, field-aged particulate filters were conducted to ascertain the effects of specific vibration frequencies and acceleration levels on ash plug break-up and transport out of the DPF channels. The results show considerable potential for the application of controlled vibrations in an offline cleaning system to aid in the removal of ash deposits plugging filter channels, thereby reducing the ash-related impact on vehicle fuel consumption and extending the useful life of the particulate filter.