Greg Rideout

The effect of fuel type and aftertreatment method on ultrafine particle emissions from a heavy-duty diesel engine

Two potential strategies for reducing diesel emissions are exhaust aftertreatment and the use of reformulated or alternative fuels. Little is yet known about the impact on ultrafine particle emissions of combining exhaust aftertreatment with such increasingly common fuels. This paper reports ultrafine particle size distribution measurements for a study in which the impact of such fuels on emissions from a heavy duty diesel engine employing different aftertreatment configurations was evaluated. Eight different fuels were tested: Canadian No. 1 and No. 2 diesel; low sulfur diesel fuel; two different ultra low sulfur diesel fuels (< 30 ppm S); Fischer-Tropsch diesel fuel; 20% biodiesel blended with ultra low sulfur diesel fuel; and PuriNOx™. The fuels were tested in combination with four exhaust configurations: engine out, diesel oxidation catalyst (DOC), continuously regenerating diesel particle filter (CRDPF), and engine gas recirculation with CRDPF (EGR-DPF). In general, aftertreatment configuration was found to have a greater impact on ultrafine particle size distributions than fuel composition, and the effects of aftertreatment tended to be uniform across the entire particle size distribution. Steady state tests revealed complex behavior based on fuel type, particularly for PuriNOx. This behavior included bimodal particle size distributions with modes as low as 8–10 nm for some fuels. Unlike previous results for gravimetric PM from this study, no significant correlation for ultrafine emissions was found for fuel properties such as sulfur level.

Nitrogen Dioxide and Ultrafine Particles Dominate the Biological Effects of Inhaled Diesel Exhaust Treated by a Catalyzed Diesel Particulate Filter

We studied the impact of a catalyzed diesel particulate filter (DPF) on the toxicity of diesel exhaust. Rats inhaled exhaust from a Cummins ISM heavy-duty diesel engine, with and without DPF after-treatment, or HEPA-filtered air for 4h, on 1 day (single exposure) and 3 days (repeated exposures). Biological effects were assessed after 2h (single exposure) and 20h (single and repeated exposures) recovery in clean air. Concentrations of pollutants were (1) untreated exhaust (-DPF), nitric oxide (NO), 43 ppm; nitrogen dioxide (NO2), 4 ppm; carbon monoxide (CO), 6 ppm; hydrocarbons, 11 ppm; particles, 3.2×10(5)/cm(3), 60-70nm mode, 269 μg/m(3); (2) treated exhaust (+DPF), NO, 20 ppm; NO2, 16 ppm; CO, 1 ppm; hydrocarbons, 3 ppm; and particles, 4.4×10(5)/cm(3), 7-8nm mode, 2 μg/m(3). Single exposures to -DPF exhaust resulted in increased neutrophils, total protein and the cytokines, growth-related oncogene/keratinocyte chemoattractant, macrophage inflammatory protein-1α, and monocyte chemoattractant protein-1 in lung lavage fluid, as well as increased gene expression of interleukin-6, prostaglandin-endoperoxide synthase 2, metallothionein 2A, tumor necrosis factor-α, inducible nitric oxide synthase, glutathione S-transferase A1, heme oxygenase-1, superoxide dismutase 2, endothelin-1 (ET-1), and endothelin-converting enzyme-1 in the lung, and ET- 1 in the heart. Ratio of bigET-1 to ET-1 peptide increased in plasma in conjunction with a decrease in endothelial nitric oxide synthase gene expression in the lungs after exposure to diesel exhaust, suggesting endothelial dysfunction. Rather than reducing toxicity, +DPF exhaust resulted in heightened injury and inflammation, consistent with the 4-fold increase in NO2 concentration. The ratio of bigET-1 to ET-1 was similarly elevated after -DPF and +DPF exhaust exposures. Endothelial dysfunction, thus, appeared related to particle number deposited, rather than particle mass or NO2 concentration. The potential benefits of particulate matter reduction using a catalyzed DPF may be confounded by increase in NO2 emission and release of reactive ultrafine particles.

Durability Studies of a Base Metal Catalyzed Particulate Filter in a Severe Non-road Application

This paper will present emissions durability data from an underground mining vehicle equipped with diesel particulate filter technology, which was followed over 4000 hrs on a Detroit Diesel Series 60 engine. The twin particulate filter system is catalyzed using a base metal formulation on cordierite wall flow monoliths. After the durability accumulation, the recovered filters were individually emissions tested on a Detroit Diesel Series 50 engine over the ISO 8178 test cycle. Performance, maintenance and emissions issues pertaining to base metal catalysts will be discussed.

Transportation Emissions: Sources and Regulation

The transportation sector accounts for a significant fraction of Canada’s criteria air contaminant (CAC) and greenhouse gas (GHG) emissions. These emissions are reviewed in this chapter separately for on-road vehicles, off-road vehicles, aviation, marine and rail sub-sectors. Each subsection aims to quantify the emissions, identify the tools and methodologies for estimating emission inventories, identify the regulations and regulatory authorities for managing the emissions, and address interactions between emission regulations and fuel regulations where appropriate. The complex emission regulations governing the transportation sector are presented in detail. The alignment of emission regulations with those in the United States and other international organizations is discussed for different sub-sectors. The relationship between CAC and GHG emissions is examined in terms of the past trends with time and projections into the future.