Exhaust Emission Concentrations Research Articles

Correction to modelling of the influence of aerosol processes for the dispersion of vehicular exhaust plumes in street environment

A paper that was previously published in Atmospheric Environment [Pohjola et al., 2003. Modelling of the influence of aerosol processes for the dispersion of vehicular exhaust plumes in street environment. Atmospheric Environment 37(3), 339–351.] contained a description of the properties of particulate matter in exhaust emissions and in urban background air. This data contained particle number concentrations and particle masses for four size classes. The mass and number concentrations of particulate matter exhaust emissions were computed correctly. However, a subsequent checking has shown that the values of particle masses of urban background air that were used in the numerical computations were one to two orders of magnitude too small, in relation to the corresponding particle number concentrations of urban background air. This has affected the numerical results on particle sizes, and produced an erroneous temporally decreasing particle size in some cases; this is notable particularly for the Aitken mode. The calculations have therefore been repeated, replacing the erroneous data with the correct data. However, the main conclusions drawn by Pohjola et al. (2003) are shown still to be valid, using the corrected input data.

비열플라즈마와 라디칼을 이용한 디젤엔진의 매연 및 NO 제거 특성

We are facing the serious environmental pollution difficulties such as acid rain, green house effects, etc. The gaseous matter NOx, SOx, VOCs which are regarded as main factors for these current pollutions are mainly emitted from power plants and vehicles. Therefore several leading countries are regulating the emissions strictly, especially the exhaust emissions from a Diesel engine without an aftertreatment device. The objective of this study is to find out soot and NO removal characteristics focused on the emissions of a Diesel engine by using nonthermal plasma for each engine speeds and loads. Electrostatic precipitator(wire-to-plate type reactor) is used for soot removal. Radicals generated from outer air and put into a mixing chamber in the end of exhaust line are used for NO removal. Concentration of exhaust emissions is analyzed from the gas analyzer(KaneMay) and FTIR to estimate by-products.

Combustion quasi-two zone predictive model for dual fuel engines

A quasi-two zone predictive model is developed in the present work for prediction of the combustion processes in dual fuel engines and some of their performance features. Methane is used as the main fuel while employing a small quantity of liquid fuel (pilot) injected through the conventional Diesel fuel system. This model emphasizes the effects of chemical kinetics activity of the premixed gaseous fuel on the combustion performance, while the role of the pilot fuel in the ignition and heat release processes is considered. A detailed chemical kinetic scheme consists of 178 elementary reaction steps, and 41 chemical species are employed to describe the oxidation of the gaseous fuel from the start of compression to the end of the expansion process. The associated formation and concentrations of exhaust emissions are correspondingly established. This combustion model is able to establish the development of the combustion process with time and the associated important operating parameters, such as pressure, temperature, rates of energy release and composition. Predicted values for methane operation show good agreement with corresponding previous experimental values over a range of operating conditions mainly associated with high load operation.

Simulation of combustion processes in gas-fuelled diesel engines

A thermodynamic multizone model incorporating detailed kinetic schemes has been developed for the prediction of the combustion processes in dual-fuel engines and some of their performance features. The consequences of the interaction between the gaseous and the diesel fuels and the resulting modification to the combustion processes are considered. A reacting zone has been incorporated in the model to describe the partial oxidation of the gaseous fuel-air mixture. The associated formation and concentrations of exhaust emissions are correspondingly established. The model can predict the onset of knock as well as the operating features and emissions for the more demanding case of light load performance. Predicted values for methane operation show good agreement with corresponding experimental values.

Analysis of Emission Formation Processes in a D.I. Diesel Engine by Total In-Cylinder Sampling. 3rd Report. Effect of Fuel Properties.

Effects of the properties of a diesel fuel, such as cetane index and aromatic content, on emission formation processes in a D. I. diesel engine were investigated using a total in-cylinder sampling technique. Two kinds of fuel, that is, DGO (desulfurized gas oil) and LCO (light cycle oil) were blended in order to obtain various cetane indexes and aromatic contents of the diesel fuel. Time histories of spatially averaged emission concentrations in a combustion chamber and exhaust emission concentrations, such as particulate, NOx and total hydrocarbon, were measured for the diesel fuels with various cetane indexes and aromatic contents. The total in-cylinder sampling results clarified the relation between the fuel properties and the emission formation characteristics in the diesel engine.

Mjere za smanjenje emisije štetnih komponenata ispušnih plinova Ottova motora

This paper deals with the measures that may be taken in the engine and outside the engine in an effort to reduce the harmful motor exhaust gas concentration emissions. These measures are being taken and elaborated with the prospect of meeting the increasingly requiring legal provisions on allowed concentrations of harmful exhaust emissions. This is meant to show the extent to which individual measures influence the level of emission of individual components, discussing at the same time the character of individual measures. The paper further reiterates the indispensability of optimization of all measures taken in the engine to reduce the emission of harmful exhaust gases to the minimum.

Independent photosynthetic response of exposed and unexposed twigs of the same spruce tree to car exhaust

AbstractIn the present paper, we address the question whether the injuries of acute toxic concentrations of exhaust emissions are due to systemic effects or are rather the result of localized and direct effects upon the needles. Twigs from exposed spruce trees, which had been prevented from contact with the exhaust emissions, did not show any decrease of photosynthetic or transpiration rates within four weeks. Chlorophyll fluorescence was also not affected in these parts, while it was severely impaired in the exposed twigs.

Test Procedures for Measuring Exhaust Emissions From Natural Gas Transmission Engines

The measurement of exhaust components from large natural gas transmission engines involves collection of the exhaust sample, transfer of the sample to the analytical instrumentation, measurement of individual component concentrations, and calculations of emission results in terms of mass, fuel specific, and brake specific rates. The major exhaust components measured include nitrogen oxides (NOx), total hydrocarbons (THC), carbon dioxide (CO2), carbon monoxide (CO), and oxygen (O2). Collection of the exhaust sample requires proper probe design and placement in the exhaust system. Transfer of the sample to the analytical instruments must maintain sample integrity from the point where the sample is removed from the exhaust stream to the point at which the sample enters the instrument for analysis. Various analytical techniques are used to measure the exhaust emission concentrations. These techniques include chemiluminescence for NOx, flame ionization for THC, nondispersive infrared (NDIR) for CO2 and CO, and polarography for O2. Calculation of the emission results in terms of mass fuel specific, and brake specific rates utilizes the measured emission concentrations, the engine operating parameters, and the “total carbon” method for data reduction and presentation.

Studies on health effects of automotive exhaust emissions how dangerous are diesel emissions?

The following paper indicates that current results of research conducted on the effects of intentionally increased concentrations of diesel engine exhaust emissions, particularly the results of animal experiments, do not lead scientifically to final conclusions. According to the current level of knowledge, we must continue to assume that the risk of cancer, possibly due to diesel particles, is negligible, particularly under real environmental conditions. The preventive measures taken by governments are of course supported by the automotive industry, an additional research outlay, however, is necessary not only to clear up contradictions and answer new questions arising from current test results, but also to take positive, and not merely precautionary, action in the future. Due to its links to other influences on humans and plants, research conducted on the effects of motor vehicle emissions is a task that lies very much in the public interest. At the same time, the overview of concluded and ongoing research objectives presented in this paper indicates that the automotive industry is greatly committed to this issue and will meet well-justified expectations.

Toxic effects of exhaust emissions on spruce Picea abies and their reduction by the catalytic converter

Exhaust emissions from automobiles have been frequently connected with a new type of forest disease which is described for conifers and, more recently, also for deciduous trees. The use of the catalytic converter for pollution control and, consequently, as a remedy for forest decline, has been extensively advocated. No data are yet available on the efficiency of catalytic devices with respect to the toxicity of exhaust emissions. We have therefore studied this question in Norway spruce Picea abies (L.) Karst. under defined conditions. The efficiency of the catalyst was tested with concentrations of exhaust emissions which produced significant injuries within a limited period of time. A fast reduction of photosynthetic capacity and impairment of stomatal regulation was observed after a fumigation of only 15 min without a catalytic converter, followed by changes in colour and, finally, by needle dropping. During the early stages, buds were not injured and developed into healthy shoots. Consequently, symptoms of an inner browning and needle dropping could be mimicked. In the presence of a catalytic converter, essentially no damage to spruce could be observed under analogous conditions.