Diesel Engine Particulate Emissions Research Articles

A new proficiency testing scheme for occupational hygiene laboratories undertaking the analysis of diesel engine particulate emissions

AbstractWe report details of a proficiency testing (PT) scheme for laboratories undertaking the analysis of diesel engine particulates (DEP) collected on workplace air filter samples. Within this occupational hygiene setting, the established approach is to measure the elemental carbon (EC) content within DEP as a specific marker of workers’ exposure to engine emissions. Measuring EC is undertaken in laboratories using combustion-based analysers. To date six, PT rounds have been completed with participation ranging between thirteen and twenty-three laboratories. In each round participants received four quartz fibre filter samples (plus blank filters) loaded with DEP with indicative EC mass loadings in the range 9–204 µg/filter. Round assigned values and standard deviation for performance assessment values were calculated by consensus from returned participant data following outlier removal. On this basis, it was determined that on average 81 % of the returned data was deemed satisfactory, i.e. returning a z (or z’) score ≤ 2. The use of two operationally defined analytical protocols, namely NIOSH 5040 and EN 16909, now dominate but they give different EC values so the preparation of reference air filter samples with preordained EC values determined using both protocols for use in future interlaboratory comparisons is therefore recommended.

Research the Effect of Oxidation Catalytic Converter on Reducing Diesel Engine Particulate Emission Based on Artificial Intelligence

Research the Effect of Oxidation Catalytic Converter on Reducing Diesel Engine Particulate Emission Based on Artificial Intelligence

Effects of Cerium Oxide and Ferrocene Nanoparticles Addition As Fuel-Borne Catalysts on Diesel Engine Particulate Emissions: Environmental and Health Implications.

This study systematically examined the potential impacts of doping CeO2 and Fe(C5H5)2 nanoparticles as fuel-borne catalysts (FBCs) to ultralow sulfur diesel (ULSD) fuel on the physical, chemical and toxicological characteristics of diesel particulate matter (DPM). The FBCs-doped fuels are effective in promoting soot oxidation and reducing the DPM mass emissions, but lead to a significant increase in the total particle counts due to the formation of self-nucleated metallic nanoparticles. Compared to undoped ULSD, the FBCs-doped fuels result in higher concentrations of particle-phase polycyclic aromatic hydrocarbons (PAHs) and n-alkanes, higher fractions of organic carbon (OC) and water-soluble organic carbon (WSOC) in particles, show slight alterations in soot nanostructure, reduce soot ignition temperature and activation energy. Exposure of the human-type II cell alveolar epithelial cells (A549) to DPM derived from FBCs-doped fuels shows a decrease in cell viability and alterations in the global gene expression with a broad range of biochemical pathways. The overall variations in DPM characteristics are mainly caused by the catalytic combustion process, and are related to the type, properties and contents of FBCs used in diesel fuel as well as the engine operating conditions. Environmental and health implications of the study are highlighted.

Manipulating modern diesel engine particulate emission characteristics through butanol fuel blending and fuel injection strategies for efficient diesel oxidation catalysts

Decoupling the dependences between emission reduction technologies and engine fuel economy in order to improve them both simultaneously has been proven a major challenge for the vehicle research communities. Additionally, the lower exhaust gas temperatures associated with the modern and future generation internal combustion engines are challenging the performance of road transport environmental catalysts. Studying how fuel properties and fuel injection strategies affect the combustion characteristics, emissions formation and hence catalysts performance can unveil synergies that can benefit vehicle emissions and fuel economy and as well as guide the design of next generation sustainable fuels. The experimental work presented here was conducted using a modern single-cylinder, common rail fuel injection system diesel engine equipped with a diesel oxidation catalyst (DOC). The impact of the fuel post-injection strategy that is commonly used as part of the aftertreatment system function (i.e. regeneration of diesel particulate filters or activity in hydrocarbon selective reduction of NOX), combined with butanol-diesel fuel blend (B20) combustion on engine emissions formation, particulate matter characteristics (size distribution, morphology and structure) and oxidation catalyst activity were studied. It was found that post-injection produced lower PM concentration and modified the soot morphological parameters by reducing the number of primary particles (npo), the radius of gyration (Rg), and the fractal dimension (Df). The results were compared with the engine operation on diesel fuel. The increased concentration of HC and CO in the exhaust as a result of the diesel fuel post-injection at the studied exhaust conditions (i.e. T=300°C) led in the reduction of the DOC activity due to the increased competition of species for active sites. This effect was improved the combustion of B20 when compared to diesel.

The design of a full flow dilution tunnel with a critical flow Venturi for the measurement of diesel engine particulate emission

An appropriate type of dilution tunnel is chosen, based on the international standards, user's needs and the manufacturer's requirements. During the design process, a number of restrictions specified in the standards for emission and Venturis were taken into account. The data required to address basic concepts were obtained from numerous emission tests performed at the IMR Institute. A short algorithm of calculation of the critical flow Venturi (CFV) is also presented. Specific attention is paid to the problems of the measurement of particulate emissions using the dilution method, which does not allow us to use the unique thermodynamic and flow parameters. A method of evaluation of particulate emissions for two extreme cases which were expected during the tests was adopted. Using the results of calculations, a full flow dilution tunnel with CFV was manufactured and tested at the IMR Institute.

Diesel engine particulate emissions: A comparison of mobility and microscopy size measurements

Sub-micron particulates emitted from diesel engines have serious negative effects on human health and environment. Accurate characterizations of such particulate matter based on independent diagnostic techniques are necessary to monitor, regulate, and model atmospheric pollution levels. The relevant sizes, in addition to mass, are of special interest as they determine the transport, toxic, optical, chemical, and deposition properties of particulates. While there is abundant information in the aerosol literature on the apparent size distributions of diesel particulates measured with mobility sizers, it is unclear how well such commercial instruments can characterize aggregated particles due to spherical interpretation and potential alterations of physical properties within extensive sampling and dilution lines. In this study, these experimental concerns were assessed by comparing equivalent size measurements from a differential mobility analyzer to the actual physical dimensions and morphologies obtained from direct TEM observations of particulates sampled from the exhaust of a diesel engine with rapid thermophoretic deposition technique. Because mobility analyzers yield an overall equivalent particulate size, the measured mobility sizes were much larger than the microscopy spherule diameters, which dictate the available surface area for their interactions with the surrounding atmosphere. Mobility size distributions were also narrower with smaller sizes compared to the TEM aggregate measurements. The average mobility diameters were found to be approximately half the average microscopy aggregate gyration diameters for the present diesel engine operating conditions. Some of the differences in fractal dimension of diesel soot aggregates were also discussed in view of the present experimental results.

The influence of engine oil on diesel exhaust emissions

AbstractIncreasingly stringent emission legislation, together with the requirements for improved diesel engine performance, such as fuel economy, friction reduction, and extended drain intervals, have led to attention being focused on engine oil quality. The use of low‐friction engine oils can improve engine fuel efficiency and lead to a significant reduction of gaseous emissions. Therefore, engine oil is of importance when considering engine design parameters.This paper describes a study of the contribution of engine oil to diesel exhaust emissions. The investigations have shown that diesel engine particulate emissions as well as hydrocarbons and NOX emissions depend on the lubricant oil properties, in particular on the sulphur content, volatility, and metal content.

Test Conditions of Diesel Engine Particulate Emission and the Results Obtained

In this work, based on experimental results, the effect of four factors of particulate emission measurements were taken into account: the method of determining the exhaust dilution in a diluting tunnel, the ratio of exhaust gases dilution, conditioning of the filters used in particle emission measurements and isokinetics of sampling a diluting tunnel.The results presented in this paper concern four chosen parameters characterizing conditions of the measurement of particle emissions. Obviously, this data does not close the question of influence on other parameters on their result measurements. They show, however, the necessity of more detailed specification on the protocol of measurements to enable comparison of various results. It is particularly important during measurements of small emissions of particles in the range expected by the rules of EURO-III and EURO-IV. It seems that the replacement of the R-49 standard by a new test cycle ESC or ETC should become a good opportunity for a deep analysis of the methods of experiments, in relation to the repeatability and reproducibility of the results.

Influence of Exhaust Aftertreatment Devices on Heavy-Duty Diesel Engine's Particulate Emissions

This paper describes the impact of two exhaust aftertreatment devices, an oxidation catalytic converter and a diesel particulate Ž lter, on the particulate emissions of a heavy-duty diesel engine, the emphasis being on diesel particulate composition and size distribution. The analysis showed that the catalytic converter did not alter the size distribution signiŽ cantly, except for an increased production of nanosized particles below 30 n miles in mean diameter. On the other hand, the ceramic monolith wall- ow Ž lter reduced the emitted particle number up to 100 times. The results again indicated that a diesel particulate Ž lter can also increase the number of nanosizedparticles. Further investigations, however, revealed that the formation of nanosized particles downstream of the oxidation catalytic converters and diesel particulate Ž lters, respectively, is biased by inadequate sampling conditions.As long as realistic sampling conditions are applied, both catalyst and Ž lter reduce particle emissions over the entire size range.

The effect of fuel additives on diesel engine particulate emissions

The effect of fuel additives on diesel engine particulate emissions

9540246 The reduction of diesel engine particulate emissions using an oxidation catalyst — The effect of high oxidation catalyst and ultra-low-sulfur fuel on reduction of diesel engine emissions Hironobu Mogi, Mitsuru Hosoya, Masatoshi Shimoda (Hino Motors, Ltd.)

9540246 The reduction of diesel engine particulate emissions using an oxidation catalyst — The effect of high oxidation catalyst and ultra-low-sulfur fuel on reduction of diesel engine emissions Hironobu Mogi, Mitsuru Hosoya, Masatoshi Shimoda (Hino Motors, Ltd.)

Modeling the regeneration of fibrous participate filter

Diesel particulate filters (traps) are effective devices in controlling diesel engine particulate emissions. Mathematical modelling can be a useful design tool in assessing the performance of particulate filters. A generalized model describing oxidation, heat and mass transfer in a porous filter substrate is developed and applied to the thermal regeneration of diesel particulate traps. In this paper, a set of dimensionless model equations are used to decrease the number of parameters and for better analysis of the regeneration process. A FORTRAN program is coded using an IMSL subroutine to solve these partial differential equations. A parametric study of the regeneration process is carried out in order to predict safe and effective regeneration conditions. Simulation results demonstrate the effects of exhaust oxygen concentration and initial trap particulate loading on the regeneration time, the mass of particulate in the trap, and the temperature of the gas and solid (particulate) interface.

Catalytic control of diesel engine particulate emission: Studies on model reactions over a EuroPt-1 (Pt/SiO 2) catalyst

The catalytic oxidation of nitric oxide to nitrogen dioxide in the presence of sulphur dioxide over a standard Pt/SiO 2 catalyst (EuroPt-1) was studied. The gas-phase reactions between nitric oxide, sulphur dioxide and oxygen were found to be insignificant under the experimental conditions concerned. The Pt/SiO 2 catalyst was observed to be very active in catalyzing the reactions both of NO + O 2 to NO 2 and of SO 2 + O 2 to SO 3. In the presence of sulphur dioxide, the catalytic activity for nitric oxide oxidation dropped dramatically, and in contrast, the presence of nitric oxide promoted sulphur dioxide oxidation. There is significant influence of NO/NO 2 on sulphur dioxide oxidation; there are indications from temperature-programmed desorption and temperature-programmed reduction (TPR) that some sort of complex species (e.g. [N x -S y -O z ]) is formed on the platinum surface. Deactivation of the catalyst was also observed during the activity tests. It is believed that the deactivation of the catalyst was mainly caused by the build-up of some nitrogen and sulphur compounds on the active sites of the platinum catalyst. Another reason for the deactivation could be the sintering of platinum particles in the reaction environment. This has been confirmed by X-ray photoelectron spectroscopy, TPR and platinum dispersion measurements.

Comparative Potency Method for Cancer Risk Assessment: Application to Diesel Particulate Emissions1

An estimation of the human lung cancer “unit risk” from diesel engine particulate emissions has been made using a comparative potency approach. This approach involves evaluating the tumorigenic and mutagenic potencies of the particulates from four diesel and one gasoline engine in relation to other combustion and pyrolysis products (coke oven, roofing tar, and cigarette smoke) that cause lung cancer in humans. The unit cancer risk is predicated on the linear nonthreshold extrapolation model and is the individual lifetime excess lung cancer risk from continuous exposure to 1 μg carcinogen per m3 inhaled air. The human lung cancer unit risks obtained from the epidemiologic data for coke oven workers, roofing tar applicators, and cigarette smokers were, respectively, 9.3 × 10−4, 3.6 × 10−4, and 2.2 × 10−6 per μg particulate organics per m3 air. The comparative potencies of these three materials and the diesel and gasoline engine exhaust particulates (as organic extracts) were evaluated by in vivo tumorigenicity bioassays involving skin initiation and skin carcinogenicity in SENCAR mice and by the in vitro bioassays that proved suitable for this analysis: Ames Salmonella microsome bioassay, L5178Y mouse lymphoma cell mutagenesis bioassay, and sister chromatid exchange bioassay in Chinese hamster ovary cells. The relative potencies of the coke oven, roofing tar, and cigarette smoke emissions, as determined by the mouse skin initiation assay, were within a factor of 2 of those determined using the epidemiologic data. The relative potencies, from the in vitro bioassays as compared to the human data, were similar for coke oven and roofing tar, but for the cigarette smoke condensate the in vitro tests predicted a higher relative potency. The mouse skin initiation bioassay was used to determine the unit lung cancer risk for the most potent of the diesel emissions. Based on comparisons with coke oven, roofing tar, and cigarette smoke, the unit cancer risk averaged 4.4 × 10−4. The unit lung cancer risks for the other, less potent motor‐vehicle emissions were determined from their comparative potencies relative to the most potent diesel using three in vitro bioassays. There was a high correlation between the in vitro and in vivo bioassays in their responses to the engine exhaust particulate extracts. The unit lung cancer risk per μg particulates per m3 for the automotive diesel and gasoline exhaust particulates ranged from 0.20 × 10−4 to 0.60 × 10−4; that for the heavy‐duty diesel engine was 0.02 × 10−4. These unit risks provide the basis for a future assessment of human lung cancer risks when combined with human population exposure to automotive emissions.

Fundamentals of soot formation in flames with application to diesel engine particulate emissions

Experimental evidence obtained on a wide variety of different combustion systems (premixed and diffusion flames, perfectly stirred reactors, etc.) and with a wide variety of different fuels indicates that chemical kinetics is the dominant rate process governing the emission of soot from the system. 56 refs.