In-Use Performance and Durability of Particle Filters on Heavy-Duty Diesel Trucks

Abstract

Diesel particle filters (DPFs) are standard equipment on heavy-duty diesel trucks with 2007 and newer engines in the U.S. This study evaluates the performance and durability of these filters. Black carbon (BC) emission rates from several thousand heavy-duty trucks were measured at the Port of Oakland and Caldecott Tunnel over multiple years as California regulations accelerated the adoption of DPFs. As DPF use increased, fleet-average BC emissions decreased, and emission factor distributions became more skewed. Relative to 2004-2006 engines without filters, DPFs reduced BC emission rates by 65-70% for 2007-2009 engines and by >90% for 2010+ engines. Average BC emission rates for 2007-2009 engines increased by 50-67% in 2015 relative to measurements made 1-2 years earlier. Some trucks in this cohort have become high-emitters, indicating that some DPFs are no longer working well. At the Port, where DPFs were universal in 2015, high-emitting 2007-2009 engines (defined here as emitting >1 g BC kg) comprised 7% of the fleet but were responsible for 65% of the total BC emitted. These observations raise concerns about DPF durability and the prospects for fully mitigating adverse effects of diesel particulate matter on human health and the environment.

A transition of atmospheric emissions of particles and gases from on-road heavy-duty trucks

“…There have been several studies on the morphology and density of combustion-generated particles and its detailed dependence on combustion and dilution condition (e.g. Maricq and Ning, 2004;Ristimaki et al, 2007;Liu et al, 2009;Zheng et al, 2011;Quiros et al, 2015). However, to be consistent, and to compare with a majority of previously reported data, unity density was used for further discussion and comparisons.…”

Comparing the Use of High- to Low-Cost Black Carbon and Carbon Dioxide Sensors for Characterizing On-Road Diesel Truck Emissions

“…For instance, the highest emitting 10% of a DPF-equipped drayage truck fleet at the Port of Oakland in California accounted for three-quarters of the fleet's total BC emissions. This level of skewness in the distribution of emissions from in-use vehicles has been widely reported across various vehicle types and pollutants [12,13,[17][18][19][20].…”

“…Emission standards for new trucks have resulted in the wide use of diesel particle filters (DPFs) to reduce tailpipe emissions of DPM, of which black carbon (BC) is major constituent, and selective catalytic reduction (SCR) systems to reduce tailpipe emissions of NO x [9,10]. Studies of in-use heavy-duty diesel trucks in California have shown marked decreases in average BC emissions within a Sensors 2020, 20, 6714 2 of 18 short span of time as fleets universally adopted DPFs [11][12][13][14]. However, a small percentage of in-use trucks in these fleets have BC emissions that are substantially higher than the average emission rate, and these high emissions may be due to deteriorating performance of aging particle filters [12,15,16].…”

“…Studies of in-use heavy-duty diesel trucks in California have shown marked decreases in average BC emissions within a Sensors 2020, 20, 6714 2 of 18 short span of time as fleets universally adopted DPFs [11][12][13][14]. However, a small percentage of in-use trucks in these fleets have BC emissions that are substantially higher than the average emission rate, and these high emissions may be due to deteriorating performance of aging particle filters [12,15,16]. For instance, the highest emitting 10% of a DPF-equipped drayage truck fleet at the Port of Oakland in California accounted for three-quarters of the fleet's total BC emissions.…”

Study of spatial and temporal aging characteristic of catalyzed diesel particulate filter catalytic performance used for diesel vehicle

“…Bai et al also found that the temperature peak appears at the rear-bed of the DPF, which will accelerate the aging of the coated catalyst 28 . The latest emission regulations put forward higher requirements for the durability of the CDPF 29 . The aging degree of the catalytic performance in the CDPF on-vehicle deepens with the using mileage, which can be reflected by the morphology and compositions of the soot and ash in the CDPF 30 .…”