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Improving fuel economy has been a key focus across the automotive industry for several years if not decades. For heavy duty commercial vehicles, the benefits from minor gains in fuel economy can lead to significant savings for fleets as well as owners and operators. Additionally, the regulations require vehicles to meet certain GHG standards which closely translate to vehicle fuel economy. For current state of the art fuel economy technologies, incremental gains are so miniscule that measurements on the vehicle are inadequate to quantify the benefits. Engineers are challenged with high level of variability to make informed decisions. In such cases, highly controlled tests on Engine and Powertrain dynamometers are used, however, there is an associated variability even with these tests due to factors such as part to part differences, deterioration, fuel blends and quality, dyno control capabilities and so on.

Ash accumulation in the DPF over life results in reduced soot storage capacity, lower catalytic activity and may even alter substrate properties and lead to higher back-pressure; hence ash-cleaning of the DPF is required periodically to extend the life of the DPF and restore its catalytic performance. Several ash cleaning technologies are available which utilize pneumatic, hydraulic and wet-chemical cleaning techniques or their combinations. A batch of DPFs with various ash accumulation levels were recovered from customer field units. X-ray CT imaging was performed to understand the ash distribution in the DPF channels. Field returned DPFs were tested on Engine Dynamometer to determine the impact on overall system performance loss from fresh state. The DPFs were then cleaned using various cleaning techniques; X-ray imaging and dynamometer testing was repeated to evaluate the performance recovery.

Diesel Particulate Filters (DPFs) have been widely used to control the particulate emissions and have become an indispensable feature of the modern diesel engines. However, DPFs also result in additional fuel consumption from added back pressure and periodic regenerations required for oxidizing the accumulated particulate matter. Aftertreatment calibrations are developed with a significant emphasis on the reducing these penalties. It is desirable to accumulate higher levels of particulate matter before regeneration and perform active regenerations at higher temperatures. This capacity is generally limited by the substrate and catalyst properties and also the inaccuracies in the DPF soot accumulation estimation. Several advancements have been made in the DPF material technologies to mitigate these limitations. This publication describes the performance of various DPF technologies.