Transient Particulate Emissions from Diesel Buses During the Central Business District Cycle

Hofeldt, David L.; Chen, Guoguang

doi:10.4271/960251

Cited by 8 publications

(4 citation statements)

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“…The second variation fits a curve through points defined by positive kinetic energy (PKE) and the corresponding emission rates (similar to the speed correction approach). Regressions of on-road heavyduty diesel PM against PKE show a strong positive correlation, but there are confounding effects associated with power transients (40,41,43).…”

Section: Introductionmentioning

confidence: 95%

“…The fourth approach, modeling diesel PM as a function of power transients, is based on observations that soot emissions are better corralled with transients in fuel injection rates than with absolute fuel use (41,45). This approach has been applied with some success in modeling diesel PM as a function of the rate of change in horse power summed over acceleration events ("severity") (46), which is perhaps the best functional relationship between vehicle activity and diesel PM emissions.…”

Section: Introductionmentioning

confidence: 99%

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On-Road Heavy-Duty Diesel Particulate Matter Emissions Modeled Using Chassis Dynamometer Data

Kear

Niemeier

2006

Environ. Sci. Technol.

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This study presents a model, derived from chassis dynamometer test data, for factors (operational correction factors, or OCFs) that correct (g/mi) heavy-duty diesel particle emission rates measured on standard test cycles for real-world conditions. Using a random effects mixed regression model with data from 531 tests of 34 heavy-duty vehicles from the Coordinating Research Council's E55/E59 research project, we specify a model with covariates that characterize high power transient driving, time spent idling, and average speed. Gram per mile particle emissions rates were negatively correlated with high power transient driving, average speed, and time idling. The new model is capable of predicting relative changes in g/mi on-road heavy-duty diesel particle emission rates for real-world driving conditions that are not reflected in the driving cycles used to test heavy-duty vehicles.

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

On-Road Heavy-Duty Diesel Particulate Matter Emissions Modeled Using Chassis Dynamometer Data

Kear

Niemeier

2006

Environ. Sci. Technol.

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“…Since real-world engine operation consists mainly of transient conditions [17] and vehicle emissions standards are regulated over transient driving cycles, the in-depth study of realistic in-vehicle operation is crucial for reducing emissions. In addition, soot emissions and visual signature are very important in military applications and are closely related to rapid vehicle/engine accelerations [18].…”

Section: Approach -Merging the Real And Virtual Worldsmentioning

confidence: 99%

Engine-in-the-Loop Testing for Evaluating Hybrid Propulsion Concepts and Transient Emissions - HMMWV Case Study

Filipi¹,

Fathy²,

Hagena³

et al. 2006

SAE Technical Paper Series

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This paper describes a test cell setup for concurrent running of a real engine and a vehicle system simulation, and its use for evaluating engine performance when integrated with a conventional and a hybrid electric driveline/vehicle. This engine-in-the-loop (EIL) system uses fast instruments and emission analyzers to investigate how critical in-vehicle transients affect engine system response and transient emissions. Main enablers of the work include the highly dynamic AC electric dynamometer with the accompanying computerized control system and the computationally efficient simulation of the driveline/vehicle system. The latter is developed through systematic energy-based proper modeling that tailors the virtual model to capture critical powertrain transients while running in real time. Coupling the real engine with the virtual driveline/vehicle offers a chance to easily modify vehicle parameters, and even study two different powertrain configurations. In particular, the paper describes the engine-in-the-loop study of a V8, 6L engine coupled to a virtual 4x4 HighMobility Multipurpose Wheeled Vehicle (HMMWV). The results shed light on critical transients in a conventional powertrain and their effect on NO x and soot emissions. Next, the conventional HMMWV powertrain is replaced with a parallel hybrid electric configuration and two power management strategies are examined. Comparison of the conventional and hybrid propulsion options provides detailed insight into fuel economyemissions tradeoffs at the vehicle level.

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“…These instruments, which were originally developed for ambient aerosol applications are successfully applied by numerous researchers in the sampling of diluted IC engine exhaust. Devices based on light extinction have recently become of interest to researchers because of their excellent time response, relative simplicity, and low cost, but they are unable to measure soluble fractions and have a somewhat poor sensitivity to low soot mass concentrations (Hofeldt and Chen, 1996).…”

Section: Sampling Methodology and Instrumentationmentioning

confidence: 99%

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

Bugarski¹

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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-...

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Transient Particulate Emissions from Diesel Buses During the Central Business District Cycle

Cited by 8 publications

References 8 publications

On-Road Heavy-Duty Diesel Particulate Matter Emissions Modeled Using Chassis Dynamometer Data

On-Road Heavy-Duty Diesel Particulate Matter Emissions Modeled Using Chassis Dynamometer Data

Engine-in-the-Loop Testing for Evaluating Hybrid Propulsion Concepts and Transient Emissions - HMMWV Case Study

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

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