Characterization of particulate matter and hydrocarbon emissions from in-use heavy-duty diesel engines

Abstract

A continued increase in the use of diesel engines in light-duty and heavy-duty vehicles, and the uncertainties about the effects of their emissions on human health have focused attention on risk assessments of diesel engine exhaust. The characterization of diesel particulate matter (PM) and hydrocarbon (HC) emissions from in-use heavy-duty diesel engines and vehicles is the primary objective toward assessing potential health hazard with exposure to the diesel exhaust. The nature of particulate matter emissions from diesel engines is dependent on the engine type, engine conditions, fuel type, exhaust after-treatment process and other parameters. The results are also strongly dependent on the applied measurement technique. The effects of those parameters on the size-resolved DPM emissions were explored in detail. The study on sizeresolved chemical analysis of DPM from diesel engines and in-use heavy-duty diesel vehicles was performed with the goal of obtaining profiles of major DPM constituents. In addition, diesel exhaust was speciated with the purpose of establishing qualitative and quantitative hydrocarbon profiles of diesel exhaust from heavyduty diesel engine/vehicles, and calculating its ozone forming potential. The effects of engine/vehicle operating conditions, fuel type, different after-treatment processes, and measurement process on the size-resolved PM emissions were examined by operating the test engines and vehicles under steady-state and transient conditions. The regional deposition of DPM in the human respiratory tract was assessed, for several cases, by applying a semi-empirical model developed by Köbritch et al. (1994) to the PM size distribution and concentration profiles that were generated in this study. The results of this analysis showed that lower PM mass emissions do not necessarily correspond to lower number count emissions and a reduced health hazard. In fact, the fractional deposition efficiency of DPM, on a count basis was higher in the case of using "cleaner" fuels than Federal diesel no. 2. The chemical analyses yielded distribution profiles of the major DPM constituents that were detected in the exhaust for selected steady-state and transient conditions. The sulfate, chloride, ammonium, potassium, sulfur and silicon distribution profiles were determined for range of engine operating conditions. Carbon analysis showed that organic carbon was the major constituent of the particulate matter collected on the MOUDI after-filters (cut-off diameter less that 56 nm) regardless of the engine operating conditions. Elemental carbon was the dominant constituent of the DPM collected on the stages VII through X, accounting for nearly 86.5 % of total carbon detected. The analyses indicate that sulfate and organic carbon were the major constituents of nanoparticles. The samples for study on hydrocarbon speciation were collected using custom designed sampling system. The system was used to collect particle bound HC on a pre-washed 70 mm Teflon coated glass fiber filters, semi-volatile HC on a PUF/XAD-...

Particulate emissions from tailpipe during idling of public transit buses fueled with alternative fuels

“…In the open literature available to authors, using source signature for finding sources of exhaust particulate matter is quite established and were used as early as by Cadle et al . , Watson [26], and Bugarski . Maricq reviewed the chemical characterization of exhaust particulate matter and outlines the use of source signature for identifying the components of exhaust particulate matter.…”

“…Source identification has been an established procedure in many society for automotive engineers (SAE) manuscripts, which is evident from their publicly available abstracts. In the open literature available to authors, using source signature for finding sources of exhaust particulate matter is quite established and were used as early as by Cadle et al [25], Watson [26], and Bugarski [27]. Maricq [28] reviewed the chemical characterization of exhaust particulate matter and outlines the use of source signature for identifying the components of exhaust particulate matter.…”

Measurement of particulate matter size, concentration and mass emissions from in-use heavy duty vehicles

“…The effect of dilution ratios is beyond the scope of this study. A comprehensive analysis of the theory and operation of this device can be found in Bugarski's (1999) study.…”

Laboratory and Real-World Measurement of Diesel Particulate Matter

“…diesel engine equipped with a Cleaire ® DPF. Previous studies have reported PM mass concentration levels at or lower than 2007 standard levels can be achieved by running this engine with a DPF and ULSD fuel [138]. As a primary indirect injection engine, its relatively high NO x emission levels in raw exhaust make it easier to determine dilution ratios inside the primary tunnel by measuring NO x concentration levels.…”