Exhaust Gas Components Research Articles

Adopted LTO cycle to operational conditions at polish airports

The aim of this article is to take into account specifications of the airport area in LTO test, when impact of the air transport at the airport- proximate area is analysed. The LTO test doesn’t con-sider the specifications of e.g. airport manoeuvring area and length of taxiways. The LTO test calculation methodology requires knowledge of aircraft engine parameters, such as thrust, spe-cific fuel consumption and emission values indexes. Based on the data contained in the Engine Emissions Database (ICAO), the parameters of the LTO test can be clearly determined. The main analysis element was to conduct a taxiing simulation using the CKAS MotionSim5 Flight Simu-lator in order to indicate the operational taxiing time at individual polish airports. Statistically significant differences were found between the emissions of selected exhaust gas components in the regulation LTO test and the operational LTO test. Analyzes were carried out in relation to three different propulsions that are most often used by carriers serving the largest number of passengers in Poland.

The Influence of Powering a Compression Ignition Engine with HVO Fuel on the Specific Emissions of Selected Toxic Exhaust Components

The aim of the research was to determine the potential of hydrotreated vegetable oil (HVO) in reducing nitrogen oxides and particulate matter emissions from the Perkins 854E-E34TA compression ignition engine. The concentrations of these toxic exhaust gas components were measured using the following analyzers: AVL CEB II (for NOx concentration measurement) and Horiba Mexa 1230 PM (for PM measurement). The measurements were carried out in the ESC test on a compression ignition engine with direct fuel injection and a turbocharger. The engine had a common rail fuel supply system and met the Stage IIIB/Tier 4 exhaust emission standard. Two fuels were used in the tests: diesel fuel (DF) and hydrotreated vegetable oil (HVO). As part of the experiment, the basic indicators of engine operation were also determined (torque, effective power, and fuel consumption) and selected parameters of the combustion process, such as the instantaneous pressure of the working medium in the combustion chamber, maximum pressures and temperatures in the combustion chamber, and the heat release rate (HRR), were calculated. The tests were carried out in accordance with the ESC test because the authors wanted to determine how the new generation HVO fuel, powering a modern combustion engine with a common rail fuel system, would perform in a stationary emission test. Based on the obtained research results, the authors concluded that HVO fuel can replace diesel fuel in diesel engines even without major modifications or changes in engine settings.

RESEARCH ON THE EFFICIENCY OF CATALYTIC CONVERSION OF EXHAUST GASES FROM A CAR ENGINE DURING WARM-UP MODE

The article is dedicated to researching the efficiency of catalytic conversion of exhaust gases from VW BBY car engine (4FS 7.65/7.56) during warm-up mode. The objective of the study is to determine the impact of structural and operational factors of emission control systems on their efficiency during the warm-up phases of car engines. A compre-hensive research methodology has been developed, which includes experimental investigations of the engine and catalyt-ic converter warm-up processes and their influence on harmful emissions. It has been established that during engine warm-up at idle, the attainment of chemical and thermal conditions necessary for the effective operation of the exhaust gas neutralization system occurs at different times: chemical conditions are reached earlier, while thermal conditions are reached later. The nominal efficiency of neutralizing various harmful exhaust gas components (CO, HC, NO) is achieved at different times and temperatures of the catalytic converter: for NO in 180 seconds at 295 °C; for CO in 220 seconds at 305 °C; and for HC in 400 seconds at 330 °C. The necessary chemical operating conditions are reached in 100 seconds at 230 °C. Furthermore, the attainment of the system’s nominal neutralization efficiency is almost independent of the time taken for the engine to reach its operational temperature based on the coolant temperature. The primary catalytic converter has little impact on emission levels in this mode due to not reaching its operational temperature. The results of the experimental research provide an opportunity to refine the theoretical model for determining the influence of structural and operational factors of emission control systems on harmful emissions and to establish a combination of factors for reducing emissions. Keywords: car engine, operating mode, fuel consumption, catalytic converter temperature, concentrations of harmful substances, exhaust gases.

Comparing modelled and measured exhaust gas components from two LNG-powered ships

Bottom-up modelling is used frequently to estimate emissions produced by seagoing vessels, and the accuracy of modelling is dependent on the data the model is trained with. Observational studies can be used to increase the model accuracy. Here we compared data from two measuring campaigns conducted on board ships that use Liquefied Natural Gas (LNG) as primary fuel in internal combustion engines (ICE) in a diesel-electric setup with values obtained from the Ship Traffic Emission Assessment Model (STEAM).The power demand for propulsion calculated using Automatic Identification System (AIS) data matched observations reasonably. The root mean square error between the modelled and observed power demand was 759–914 kW (28.6–34.5%) for the measured ropax vessel and 1869–1916 kW (16.7–17.1%) for the large cruise vessel over four voyages while the ships were underway. The discrepancy is largely explained by the auxiliary power demand, which was 4 times higher on the large cruise vessel than the model prediction.Using meteorological data to estimate the increase of resistance did not improve the goodness of fit between modelled and observed engine power demand. STEAM model's base-specific fuel consumption calculation method fits observed values reasonably when the engine load is over 50%, but ICEs used in constant speed mode have increased consumption at lower engine loads compared to variable speed ICEs.The share of pilot fuel of total energy consumption was found to play a significant role in the emission factors for measured exhaust gas compounds. More accurate functions to model fuel consumption and emissions were derived using the observed data.

THE IMPROVEMENT OF THE ECONOMIC AND ENVIRONMENTAL CHARACTERISTICS OF COGENERATION PLANTS BASED ON HEAT ENGINES WITH THE THERMOCHEMICAL METHOD OF CLEANING THEIR EXHAUST GASES

The article presents the results of research aimed at improving the economic and environmental characteristics of cogeneration plants based on heat engines (ICE, GPE, GTU), with a thermochemical device for the neutralization of harmful components of its waste gases, and a boiler-utilizer (BU). The neutralization process takes place in a layer of red-hot carbon material and a gaseous medium, which includes: methane, hydrogen and carbon monoxide. The effectiveness of the proposed process was investigated both analytically, using specialized computer programs for energy management, and experimentally, by a special laboratory device, which made it possible to simulate in a wide range of temperatures (500...1000°C) how the products of natural gas combustion (the base fuel for the GPA and GTU), with a defined coefficient of excess air (oxygen), as well as the concentration of CO and NOx in their composition. The primary task of the experimental study was to determine the effect of temperature on the neutralization of nitrogen oxides and carbon monoxide in natural gas combustion products. The results of the studies (in the considered temperature range of 750...950℃) showed the possibility of reducing the concentration of nitrogen oxides by 2.5...3 times, and the concentration of carbon monoxide by almost 5 times. At the same time, it was established that the efficiency of NOx neutralization at the considered temperature range does not change significantly (within 10%), which makes it possible to carry out the neutralization process at a temperature of 750...780℃ and reduce the energy cost. The final neutralization of the exhaust gases of the engine and the utilization of their thermal potential is carried out in the boiler-utilizer. The placement of the thermochemical device in front of the boiler-utilizer, on the one hand, changes the thermal characteristics of the cogeneration plant to direction of increasing its heat loads, and on the other hand, increases the maneuverability of the plant, providing possibility of independent change of electrical and thermal load. In addition, the use of solid fuel with its gasification in the device allows not only to neutralize the harmful components of the engine's exhaust gases, but also to provide a partial replacement of natural gas in the engine and the boiler - utilizer with a corresponding reduction of thermal and harmful emissions in to the environment.

Simulation of alternative fuel combustion process in internal combustion engines

BACKGROUND: The tasks of improving fuel efficiency and environmental performance of engines are interrelated with the technical, economic, resource performance and reliability of their operation. AIM: In this regard, the aim is simulation of the alternative fuels combustion process. METHODS: To achieve this aim, the method for preparing a water-fuel emulsion mixed with diesel fuel has been developed and experimental studies have been carried out with the measurement of toxic components of exhaust gases from diesel engines. RESULTS: As a result of the research, the most optimal droplet sizes of water-fuel emulsions were revealed after 4–6 processing cycles with the smokiness reduction by 3 to 5 times, the NOx reduction by 2 to 3 times, the CO reduction by 20–30%, depending on the operating modes. CONCLUSIONS: As a result of the research, it was found that the use of alternative fuels makes it possible to expand the fuel balance and to improve environmental performance.

Exploring NH3 combustion in environments with CO2 and H2O via reactive molecular dynamics

In existing power units such as internal combustion engines and gas turbines, the combustion of ammonia mixed with hydrocarbon fuels can effectively enhance the combustion intensity of ammonia. In the duel-fuel combustion scenario, the effect mechanism of the main components of combustion exhaust gas i.e., CO2 and H2O on ammonia combustion is still unclear and needs to be studied. Therefore, this paper uses reactive molecular dynamics simulations to study the combustion and emission processes of ammonia in environments with CO2 and H2O. The effects of the diverse gas environments (N2/O2, O2/CO2, and O2/CO2/H2O environments), high CO2 levels, varying H2O proportions, and O2 concentrations on ammonia combustion and emission were systematically explored. It was found that ammonia consumption was accelerated in the O2/CO2/H2O environments compared to N2/O2 environments, resulting in more NH2, H2, and H2O production. The effect of high CO2 concentration on ammonia oxidation was mainly related to temperature. The simulations found that the high CO2 concentration inhibited ammonia consumption at T < 2800K while enhancing it at T ⩾ 2800K. In addition, the high CO2 concentration could inhibit NO production under stoichiometric conditions but promote the conversion of nitrogen-containing intermediates to NO with the oxidizing capacity of CO2 enhanced significantly under extremely high temperature conditions. It was found that the increasing content of H2O molecules in the environment promoted NO production and inhibited CO production under stoichiometric conditions. In addition, the reaction paths for the conversion of HNO and HNO2 molecules into NO molecules were significantly enhanced with increasing H2O concentration. The increase in oxygen concentration can promote OH radical production and NO formation at high temperatures.

Transport ecology in the context of the coronavirus pandemic

The work is devoted to the analysis of the latest data on the study of socio-hygienic and environmental consequences, a pandemic in conditions of a high level of atmospheric air pollution, the effect of solid and gaseous components of exhaust gases from automobiles and industry on human health and the environment.The object of the study is the atmospheric air polluted by the viral infection COVID-19. Action to tackle air pollution is particularly relevant in the wake of the outbreak of the coronavirus pandemic, according to research from the Harvard School of Public Health (USA), which Bellona has already written about, as well as reports from European scientists at the University of Siena School of Medicine (Italy). The dependence of health and mortality rates on air quality is a fact repeatedly confirmed. According to the World Health Organization (WHO), currently 9 out of 10 people in the world breathe polluted air, and this leads to 7 million additional deaths annually. WHO officials say that one third of deaths from stroke, lung cancer and heart disease are due to air pollution: “This death is caused by exposure to fine particulate matter 2.5 microns or less (PM 2.5) in diameter, which leads to the development of cardiovascular, respiratory and oncological diseases".

Assessment of the functioning of biofuel-powered engines based on a multi-criteria analysis

Reducing the emission of exhaust gas components into the natural environment from the transport sector is a priority. In recent years, the European Union has published many legal acts that regulate the emission of exhaust gas components. One of the known ways to reduce them is to use alternative fuels to power combustion engines. The paper presents an assessment of the functioning of drive units powered by mixtures of diesel oil and fatty acid methyl esters. The AHP (analytic hierarchy process) method was used for the analysis, which made it possible to determine the values of individual assessments. Based on the analysis, it was found that the lowest exhaust emission parameters were obtained for a fuel mixture containing 30% fatty acid methyl esters.

Inlet baffle structural optimization and reforming performance of exhaust gas-fuel reformer for marine LNG engine

The structural and boundary conditions are pivotal factors influencing the performance of the reformer. However, previous research primarily relied on tailored theoretical boundary conditions specific to the research requirements, often conducted in low airspeed conditions ranging from 700 ℃ to 1000 ℃. There is a lack of research focused on the complex and dynamic process of reforming hydrogen production process in reformers that handle exhaust gas components with high flow rates, high dilution, complex compositions, and low to medium temperatures (300 °C–600 °C) as boundary conditions. The objective of this study is to optimize the structure of the reformation reactor while exploring its hydrogen reforming characteristics. Therefore, this study focused on the simulation-based optimization design of an EGR reformer for marine natural gas engines. A comprehensive model was developed by coupling fluid flow, heat transfer, and surface reactions on a nickel-based catalyst. The accuracy of the model was validated through experimental data from a single-tube fixed-bed catalytic reforming experiment. The results highlighted the importance of the reformer design, with the optimal configuration incorporating two baffle plates positioned at angles of 15° and 35°. This design achieved the most uniform flow field and minimal pressure drop among the six investigated configurations. Furthermore, the study emphasized the significance of reforming gas composition in achieving high performance. The optimal reforming gas composition was found to have an M/O value of approximately 2 and an S/M value of approximately 1. This resulted in an outlet hydrogen concentration of approximately 18.8%, hydrogen yield of approximately 46.1%, methane conversion rate of approximately 66.2%, and an energy efficiency of 71%. It was observed that increasing the EGR rate led to a decrease in performance indicators, with a more pronounced effect observed at an M/O value of 1. This study provides valuable insights into the performance optimization of EGR reformers for marine natural gas engines. The findings offer guidance on selecting operational parameters to enhance efficiency and hydrogen production.

Exhaust Emissions from Euro 6 Vehicles in WLTC and RDE—Part 2: Verification by Experimental Measurement

The subject of assessing exhaust emissions in real driving conditions has been relevant for a long time. Its introduction into approval tests focused attention on the comparative possibilities of tests performed on a chassis dynamometer and in road conditions. The article is a continuation of research on the possibilities of estimating emissions in the Real Driving Emission test based on emission data from Worldwide harmonized Light Vehicles Test Cycles. The first part discussed the possibility of comparing dynamic parameters in these tests, and the second part discussed the possibility of estimating road exhaust emissions. The work was done in two stages: the first stage involved the use of distance-specific emissions in individual parts of the WLTC test, and the second stage involved the use of exhaust emission rates as datasets divided into intervals defined by vehicle speed and acceleration. Comparative tests were performed for conventional vehicles (gasoline, diesel) and hybrid vehicles. A chassis dynamometer was used to carry out WLTC tests and PEMS equipment was used for the RDE tests. The exhaust gas components that had to be measured in road tests, namely: carbon monoxide, carbon dioxide, nitrogen oxides, and the number of particulate matter, were analyzed. Based on the data collected, parameters such as road emissions and the exhaust emissions rate were determined for each phase of the dynamometer test as well as the road test. Because of this, it was possible to compare the distance-specific exhaust emissions of each vehicle in the two emission tests. The comparison resulted in establishing that it is possible to estimate distance-specific exhaust emissions of conventional and hybrid vehicles in road test conditions, using only the results obtained in the approval test (for selected test phases). The research concluded that it is possible to estimate selected RDE test parameters based on the results obtained in the WLTC test for the tested vehicles.

Determination of Rational Design Values for Gas-Air Coolers Components of Exhaust Gases of Marine Power Plants

Abstract Modernisation of marine power plants in the transport vessel fleet to satisfy the requirements of the International Maritime Organization is an urgent scientific and technical problem. Currently, the use of catalytic selective filters, dry and wet scrubber systems and exhaust gas recirculation for marine diesel engines is widely used for this purpose. An analysis of the use of ejection gas-air coolers is presented as an additional method of emission reduction. However, the use of such device does not neutralise the harmful emissions of power plant engines, but only increases the volume concentration of their exhaust gases. But this will help to increase the efficiency of dispersion of harmful emissions, by reducing the concentration of harmful emissions to values not exceeding the maximum permissible concentrations. Its efficiency depends on the load mode of the diesel engine. It is found that the initial concentration of harmful substances in combustion products due to their dilution with fresh air at 100% engine load is reduced by about 50%. The values of the reduction of the concentration and temperature of exhaust gases with the reduction of the engine load to 75% and 50% depending on the louvre angle are obtained. It is proved that ejection gas-air coolers can be an effective additional means for compliance with modern environmental parameters, especially when vessels are in special areas of the world’s oceans.

Comparison of operational parameters and stability of performance of an automotive SI engine powered by methyl and ethyl alcohols

The article presents research results performed using automotive spark ignition engine run on methyl and ethyl alcohols as well as gasoline as reference fuel. The research was performed on automotive engine of Fiat 1100 MPI type. The subject of the performed analysis was to compare operational parameters of the engine such as: engine power output, overall efficiency, emission of toxic components of exhaust gases, as well as comparison of course of combustion process calculated on the basis of recorded and averaged indicator diagrams, and on the basis of individual combustion cycles. The averaged diagrams were used in analysis of the pressure course during combustion, in analysis of pressure growth rate and heat release rate. Diagrams of individual combustion served for assessment of operational smoothness of the engine when fueled with alcohols. As the reference, parameters measured in case of gasoline fueling were used. The experiments have confirmed stable engine operation on methyl and ethyl alcohols. Increase of engine power output with o 3.8-7.7% was confirmed for methanol and with 1.7-3.3% for ethanol, while increase of the efficiency with 1.5-7.5% was confirmed for methanol and with 1.2-2.5% for ethanol, comparing with gasoline fueling. Obtained results are pointing at possibilities of fueling of modern SI engines with alcohols only, especially including water-logged ethyl alcohol, obtained directly from distillery. This should increase share of alcohols in overall balance of consumed engine fuels.

Fuel systems of high power stationary engine

The use of alternative fuels and, in the future, synthetic fuels has forced changes in the design of fuel supply systems in internal combustion engines. When operating a stationary engine at constant load, the possibility of using lean fuel mixtures appears. Selection of a precisely operating mixture ignition system requires changes in traditional fuel systems. The article presents the current designs of fuel supply systems and their properties. Attention was paid to operating parameters resulting in acceptable emissions of toxic exhaust gas components. Control systems that make the operation of the fuel system dependent on the properties of fuels are being developed.

Investigations into the performance and emissions of a small-scale CHP system using producer gas obtained from gasification of forest residues

The cost of wood, which form traditional feedstocks for biomass gasification, has been sharply increasing in recent years. Hence, low cost alternative feedstocks, such as forest residues, need to be explored to retain the economical edge. Forest residues (FR) are the materials left behind on the forest floor after forest harvesting and management activities. The present study explores the effect of forest residues as feedstock in a downdraft gasifier coupled with a small-scale combined heat and power (CHP) system, consisting of a diesel engine-alternator setup. The findings reveal that the FR mixtures change the flow behaviors of both feedstock and air in the reactor. While the average composition of the producer gas is similar to that of wood chips, a stratified bed with uneven flow leads to an unpredictable nature in the equivalence ratio which is a process controlling parameter. This is also reflected in gas parameters such as the heating value and cold gas efficiency, which in turn leads to unpredictability in the overall performance of the CHP system, evident in its electrical and thermal efficiencies, and exhaust gas components like CO, CO2, and NOx. Diesel substitution rates (DSR) of up to 59% and 46% for partial and full electrical loads respectively were realized. While emissions of CO and CO2 increased with increasing DSR, supplementing diesel with producer gas has benefits in terms of the pollutants NOx and PM, which were found to be generally lower for the FR mixtures. In the case of NOx, reductions of over 65% was achieved.

The Decomposition of Dilute 1-Butene in Tubular Multilayer Dielectric Barrier Discharge Reactor: Performance, By-Products and Reaction Mechanism

Butene is a typical component of exhaust gas in the petrochemical industry, the emission of which into the atmosphere would lead to air pollution. In this study, a tubular multilayer dielectric barrier discharge (TM-DBD) reactor was developed to decompose 1-butene at ambient pressure. The experimental results show that a decomposition efficiency of more than 99% and COx selectivity of at least 43% could be obtained at a specific energy density of 100 J/L with an inlet concentration of 1-butene ranging from 100 to 400 ppm. Increasing the volume ratio of O2/N2 from 0 to 20% and the specific energy density from 33 to 132 J/L were beneficial for 1-butene destruction and mineralization. Based on organic byproduct analysis, it was inferred that the nitrogenous organic compounds were the main products in N2 atmosphere, while alcohol, aldehyde, ketone, acid and oxirane were detected in the presence of O2. In addition, the contents of formaldehyde, acetaldehyde, ethyl alcohol, acetic acid and propionic acid increased with an increase in specific energy density, but the contents of propionaldehyde, ethyl oxirane, butyraldehyde and formic acid decreased. Three main pathways of 1-butene destruction were proposed involving Criegee intermediates and ozonolysis of the olefins, and the following degradation could be the dominant pathways rather than epoxidation. Overall, the developed TM-DBD system paved the way for scaling up the applications of plasma technology for gaseous pollutant decomposition.

Impact of Hydrogen Mixture on Fuel Consumption and Exhaust Gas Emissions in a Truck with Direct-Injection Diesel Engine

Hydrogen addition affects the composition of exhaust gases in vehicles. However, the effects of hydrogen addition to compression ignition engines in running vehicles have not been evaluated. Hydrogen-mixed air was introduced into the air intake of a truck equipped with a direct-injection diesel engine and running on a chassis dynamometer to investigate the effect of hydrogen addition on fuel consumption and exhaust gas components. The reduction in diesel consumption and the increase in hydrogen energy share (HES) showed almost linear dependence, where the percentage decrease in diesel consumption is approximately 0.6 × HES. The percentage reduction of CO2 showed a one-to-one relationship to the reduction in diesel consumption. The reduction in emissions of CO, PM, and hydrocarbons (except for ethylene) had one to one or a larger correlation with the reduction of diesel consumption. On the other hand, it was observed that NOx emissions increased, and the percentage increase of NOx was 1.5~2.0 times that of HES. The requirement for total energy supply was more when hydrogen was added than for diesel alone. In the actual running mode, only 50% of the energy of added hydrogen was used to power the truck. As no adjustments were made to the engine in this experiment, a possible disadvantage that could be improved by adjusting the combustion conditions.

Vehicle Emission Models and Traffic Simulators: A Review

Accurate estimations and assessments of vehicle emissions can support decision-making processes. Current emission estimation tools involve several calculation methods that provide estimates of the exhaust components that result from driving on urban arterial roads. This is an important consideration, as the emissions generated have a direct impact on the health of pedestrians near the roads. In recent years, there has been an increase in the use of emission models, especially in combination with traffic simulator models. This is because it is very difficult to obtain an actual measurement of road emissions for all vehicles travelling along the analysed road section. This paper concerns a review of selected traffic simulations and the estimation of exhaust gas components models. The models presented have been aggregated into a group with respect to their scale of accuracy as micro, meso, and macro. This paper also presents an overview of selected works that combine both traffic and emission models. The presented literature review also emphasises the proper calibration process of simulation models as the most important factor in obtaining accurate estimates. This work also contains information and recommendations on modelling that may be helpful in selecting appropriate emission estimation tools to support decision-making processes for, e.g., road managers.

Application of a Robust Thermoelectric Gas Sensor in Firewood Combustion Exhausts

The quality of wood combustion processes can be effectively improved by achieving the automated control of the combustion air feed. For this purpose, continuous flue gas analysis using in situ sensors is essential. Besides the successfully introduced monitoring of the combustion temperature and the residual oxygen concentration, in this study, in addition, a planar gas sensor is suggested that utilizes the thermoelectric principle to measure the exothermic heat generated by the oxidation of unburnt reducing exhaust gas components such as carbon monoxide (CO) and hydrocarbons (CxHy). The robust design made of high-temperature stable materials is tailored to the needs of flue gas analysis and offers numerous optimization options. Sensor signals are compared to flue gas analysis data from FTIR measurements during wood log batch firing. In general, impressive correlations between both data were found. Discrepancies occur during the cold start combustion phase. They can be attributed to changes in the ambient conditions around the sensor housing.

Neutralization of Acidic Exhaust Gas Components by Overbased Additives in Marine Oils: Effects of the Acid Composition on the Neutralization Mechanism

Using a combination of IR spectroscopy and small-angle X-ray scattering methods, the study investigates the initial steps of the neutralization of commercial additives, such as overbased calcium alkylbenzene sulfonate and calcium alkyl salicylate, by a number of model acids. The model acids included sulfuric acid, nitric acid (both simulating acidic products of marine fuel combustion), and acetic acid. For the sulfonate additive, it was shown that the amorphous CaCO3 core crystallizes, predominantly into vaterite, with a simultaneous slight increase in the size of the additive’s solid core. In the case of the salicylate additive, no CaCO3 crystallization was observed, and the solid core was slightly reduced in size. The paper proposes an explanation for these transformations, which rests on the difference in the strength of the acids that constitute the shell of the additive’s nanoparticles, and in the water solubility of the calcium salts produced.