Engine Exhaust Gas Research Articles

Corona Discharge Characteristics in Electrostatic Precipitator Under High Temperature

Harmful substances, such as particulate matter (PM), nitrogen oxides, and sulfur compounds in exhaust gas emitted from marine diesel engines have a great impact on the air environment. Among them, especially black carbon in PM has a negative effect on global warming. The exhaust gas from marine diesel engines using fuels containing heavy fuel oil has a high PM concentration and high temperature. Therefore, a commonly used diesel particulate filter is not suitable for collection because it tends to cause clogging and reduce efficiency. Furthermore, it is often the case that ships are at sea for more than one month, so it is difficult to replace the filter, that is, maintenance is difficult. On the other hand, an electrostatic precipitator (ESP) has the advantages of a simpler structure, lower pressure loss, and higher collection efficiency of high concentration particles. This suggests that the ESP is suitable for collecting harmful substances from the marine diesel exhaust gas. At high temperatures, corona discharge is unstable, and a flashover tends to occur at low applied voltage. Therefore, it is necessary to study the stable corona discharge generation range for the stable operation of the ESP. The purpose of this research is to analyze the optimal electrode structure and its corona discharge characteristics under the simulated exhaust gas of a diesel engine in the range of 100 °C – 400 °C using a negative dc power supply.

Pregled ekoloških parametara brodskih dizel motora

The by-pass system of exhaust gas for the engine 6L20 Wartsila has been observed. The requirements of Annex VI MARPOL towards nitrogen oxide concentration in ship engine exhaust gases have been provided. The purpose of research was the determination of diesel 6L20 Wartsila by-pass exhaust gases optimum volume – at this the nitrogen oxide minimal concentration in exhaust gases is assured, the minimal increase (comparing with operation mode without by-pass) – specific effective fuel consumption, supporting of necessary thermal factor diapason of engine cylinders. The research was performed for the exhaust gas by-pass diapason 0…10 % with engine load diapason 0.55…0.85 % from nominal power. Upon experimental results it has been stated that the exhaust gas by-pass usage favors the ecological parameters of ships engine operation modes – by this at the range of exploitation load 0.55…0.85 % from nominal power the nitrogen oxide concentration in exhaust gas is decreased to 1.32….12.97 %. The exhaust gas by-pass impairs the combustion process and favors the increasing of specific effective fuel consumption and increasing the temperature of exhaust gases. The exhaust gas by-pass system effectiveness assessment should be performed by complex estimation of the following engine operation parameters: the nitrogen oxide concentration in exhaust gas, increasing of specific effective fuel consumption(SFOC), the exhaust gas temperature. As optimal degree of exhaust gas by-pass value when the maximum decrease of nitrogen oxide emission at minimal increase of fuel consumption and simultaneous engine thermal factor handling has to be considered.

Correction and Fitting Civil Aviation Flight Data EGT Based on RPM: Polynomial Least Squares Analysis

There are different missing flight data due to various reasons in the process of acquisition and storage, especially in general aviation, which cause inconvenience for flight data analysis. Effectively explaining the relationship between flight data parameters and selecting a simple and effective method for fitting and correcting flight data suitable for engineering applications are the main points of the paper. Herein, a convenient and applicable approach of missing data correction and fitting based on the least squares polynomial method is introduced in this work. Firstly, the polynomial fitting model based on the least squares method is used to establish multi-order polynomial by existing flight data since the order of the least squares polynomial has a direct impact on the fitting effect. The order is too high or too small, over-fitting or deviation will occur, resulting in improper data. Therefore, the optimization and selection of the model order are significant for flight data correction and fitting. Because the flight data of the aircraft engine exhaust gas temperature (EGT) are often lost because of the immature detection technology, a series of the multi-order polynomial are established by the relationship of aircraft engine exhaust gas temperature and Revolutions Per Minute (RPM). Case study results confirm the optimal model order is four for the fitting and correction of aircraft engine exhaust temperature, and the least squares polynomial method is applicable and effective for EGT flight data correction and fitting based on RPM data.

A Review of the External and Internal Residual Exhaust Gas in the Internal Combustion Engine

Efficiency and emission reduction are the primary targets of internal combustion engine research due the large number of vehicles in operation and the impact of emissions-related pollution on human and ecosystem health. Harmful components of engine exhaust gases include nitrous oxides (NOx), carbon dioxide, hydrocarbons, and particulate matter. NOx emissions in particular are associated with significant health threats. The recirculation of exhaust gases can reduce NOx emissions and improve engine efficiency when combined with other advanced techniques. On the other hand, the residual exhaust gas also effects on the quality of lubricating engine oil and therefore causes an increase in engine piston ring wear. In this review paper, the effects of external and internal exhaust gas recirculation on the performance and emission characteristics of diesel, gasoline, and alternative fuel engines are summarized and discussed in detail. Because it is difficult to estimate the internal residual exhaust gas in the combustion engine by doing experiments. This review paper introduces control strategies and prediction methods for internal and external exhaust gas recirculation.

DI-CNG injector nozzle design influence on SI engine standard emissions and particulates at different injection timings

Compressed natural gas direct injection (DI-CNG) systems in spark ignition (SI) internal combustion engines have shown that it can give several benefits compared to CNG port fuel injection systems. However, the DI-CNG injector nozzle head design and gas jet formation may greatly influence engine exhaust gas emissions and performance. Present experimental study investigated the influence of 7 different nozzle head designs of spray-guided DI-CNG injectors on the combustion process, engine performance, standard emissions, and particulate number (PN) when methane fuel was injected at different injection timings (SOI) and injection pressures (18 bar and 50 bar). The nozzle heads had two main design patterns – heads with small multi holes/orifices and heads with larger crevices (swirl or umbrella spray pattern). Naturally aspirated SI engine tests were conducted at part load (6 bar IMEP) and wide-open throttle (WOT) at 2000 rpm engine speed. The results revealed that the difference between the nozzle heads was small when the fuel was injected at an early stage of the intake stroke (310–350 CAD bTDC) either at part load or high load. However, for late injection timing (130–190 CAD bTDC), the design of the DI-CNG injector nozzle head had a large impact on the combustion stability, standard emissions formation and particulates. Multi-hole nozzle heads showed improved CO2, CO, THC, total PN, and slightly higher NOx emissions compared to nozzle heads with larger crevices. For some of the nozzles, the SOI could be retarded more than for other injector head designs at higher injection pressure whilst still ensuring an acceptable engine performance in terms of combustion stability, power output and emissions formation. Overall, 50-bar injection pressure and a late injection timing under WOT conditions achieved higher engine load levels with all injector nozzle types. Images acquired using an optical endoscope technique with a high-speed video camera showed that a yellow flame was present for all nozzle types at a low injection pressure and late SOI. Increasing the injection pressure reduced the injection duration, improved air/fuel mixing which resulted in the reduced yellow flame formation and lower PN for most of the nozzle heads.

A recent review on waste heat recovery methodologies and applications: Comprehensive review, critical analysis and potential recommendations

Due to global warming and environmental issues in recent times, the world's concern is oriented nowadays toward discovering new renewable energy sources and energy management methods. Particularly, researchers are emphasizing on heat recovery technologies and applications in both residential and industrial sectors. While there are plenty of review papers in the literature on the subject matter, there is always a necessity to update the literature with the new advancements in the field. In this context, the purpose of this paper is to present a recent and complete systematic comprehensive review along with critical analysis and potential recommendations related to waste heat recovery (WHR) methodologies and applications. In methodologies, heat exchangers, Rankine cycle and thermoelectric generators are studied. Moreover, applications of WHR are discussed in automotive, and in both residential and industrial zones. Studies show that the optimization of heat recovery systems lead to significant magnitudes of energy savings. On the other hand, hybrid heat recovery systems prove to be the most trending research subject nowadays. For future work, the negative effect of backpressure should be taken into consideration when recovering energy from exhaust gases of engines and power generators, and more importance should be given to hybrid systems.

Improving the environmental safety of vehicle operation by using flywheel batteries

Despite the fact that according to the largest international organization “Our World in Data”, air pollution mortality is decreasing - mainly due to improved indoor air - this type of environmental pollution is one of the world’s leading risk factors. In 2017 approximately 5 million people around the world died from diseases caused by air pollution – strokes, lung cancer, etc. The prevailing part (about 40% of the world’s air pollution) occurs when vehicles are used, mainly personal vehicles, which means that it is necessary to develop measures to improve the environmental friendliness of the use of vehicles. Since the exhaust gases of automobile engines contain a large amount of air pollutants, it is possible to limit their emissions by developing and implementing hybrid vehicles with flywheel energy accumulators. The article considers the dimensionless dependence of the current acceleration of the car to its maximum acceleration in the presence and absence of a flywheel in the system, and checks the reliability of the dependence on the stand.

Development of a methodology for calculating the integral toxicity of exhaust gases of a diesel engine running on alternative fuels

Currently, most methods for assessing the content of harmful substances in the exhaust gases (EG) of diesel internal combustion engines (DICE) differ in research programs that simulate the most significant operating modes of a tractor or motor vehicle DICE in ordinary operating conditions. And to assess their toxicity, such different methods are used as a study under steady-state operating modes that ensure the constancy of the performance of a DICE, and its study under changing parameters in transient modes. DICE of tractors, self-propelled agricultural machines and other off-road equipment are tested at a stand equipped with a loading device and measuring instruments for monitoring tests and collecting data necessary for processing test results. Emissions are determined during the sequential operation of the DICE at steady-state modes. Each mode has its own weighting coefficient, which characterizes the contribution of this mode to environmental pollution during the operation of a DICE.

Rankine cycle waste heat recovery for a heavy-duty natural gas engine meeting China VI emission standards

The China VI natural gas engine is based on the theory of the air–fuel ratio method, leading to a high exhaust temperature, large heat load and difficult cooling. The paper carried out a thermal balance experiment of the China VI natural gas engine under different working conditions. A dual-loop organic Rankine cycle system is designed to reduce the difficulty of cooling system and improve the thermal efficiency. The high-temperature loop uses water as working fluid to recover the heat of engine exhaust gas and recirculation exhaust gas. The low-temperature loop recovers the heat from cooling water and waste heat of the high-temperature loop. The high-temperature and low-temperature loops are coupled through a shared heat exchanger. The results show that the China VI natural gas engine has a higher and more stable waste heat temperature than traditional engines and is more adaptable to waste heat recovery under variable operating conditions. For fixed evaporation temperature, with the increase of inlet temperature of the expander, the net output power of high-temperature loop increases first and then decreases, reaching the maximum value at about 800 K. In the low-temperature loop working fluids R601a, R601b, R600, R600a and R12333zd, The maximum net output power of the waste heat recovery system based on the combination of water and R12333zd is approximately 75.4 kW under the rated condition, which is 22.24% of the rated power of the engine.

An Engine Exhaust Utilization System by Combining CO2 Brayton Cycle and Transcritical Organic Rankine Cycle

For engine exhaust gas heat recovery, the organic Rankine cycle (ORC) cannot be directly used due to the thermal stability and safety of organic fluids. Thus, a creative power system is given by integrating the supercritical CO2 Brayton cycle and transcritical ORC. This system can directly utilize the thermal energy of a high-temperature exhaust gas. The inefficiencies in the heat exchangers are highly reduced by using supercritical working fluid. The mathematical model of the system, covering both the thermodynamic and economic aspects, is built in detail. It is found that the highest irreversible loss takes place in the gas heater, taking 21.14% of the total exergy destruction. The ORC turbine and CO2 turbine have the priority for improvement, compared to the compressor and pump. The increase in CO2 turbine inlet pressure improves the system exergy efficiency and levelized cost of energy. Both the larger CO2 and ORC turbine inlet temperatures contribute to a decrease in levelized cost of energy and a rise in system exergy efficiency. There is a maximum value of system exergy efficiency and minimum value of levelized cost of energy by varying the ORC turbine inlet pressure. The determined exergy efficiency and levelized cost of energy in the proposed system are 54.63% and 36.95 USD/MWh after multi-objective optimization.

Technology for obtaining a deposited catalyst based on an aluminosilicate matrix modified with europium oxide

The number of cars used worldwide is constantly growing. In this regard, the problem of combating atmospheric pollutants - exhaust gases of internal combustion engines is of particular relevance. Over the years, automakers have made many improvements to car engine design and fuel systems to meet pollution limits. One of the best solutions to this problem is the use of a so-called catalytic converter (converter) or simply a catalyst with a high content of noble metals, the main function of which is the simultaneous oxidation of unburned hydrocarbons and CO, as well as the reduction of nitrogen oxides. It was found that the addition of rare earth metals to Pd, Pt catalysts improves their properties and reduces the proportion of noble metals in the composition of catalysts. The paper presents the results of a study of complexation in the Eu3+-ligand system, where the ligand is an organic acid, by photocolorimetric and potentiometric methods. In the Eu3+-gallic acid system, a stable complex of the composition MeLnx – 1:2 is formed. In the Eu3+- oxalic acid system, a stable complex of the composition MeLnx – 1:1 is formed. In the Eu3+-valine system, a stable complex of the composition MeLnx – 1:2 is formed. A new technique for obtaining complex compounds is shown, consisting in adding hydrogen peroxide H2O2 to a solution containing solutions of Eu3+ salt and organic acid in an aqueous-alcoholic medium to block the reduction of Eu3+→Eu2+. A technology for obtaining a automotive catalyst has been developed, consisting of successive stages: obtaining complex compounds, applying the obtained complex compounds to ceramic block matrices, drying, applying platinum (palladium) acid, calcination. The presence of the Eu3+ ion in the ceramic matrix is proved by the method of elemental analysis. The technology can be applied to solve the problem of environmental pollution, such pollutants as exhaust gases of cars containing a lot of harmful substances in their composition.

ОЦЕНКА ВОЗДЕЙСТВИЯ ДИЗЕЛЕЙ ЖЕЛЕЗНОДОРОЖНОГО ПОДВИЖНОГО СОСТАВА НА ПАРНИКОВЫЙ ЭФФЕКТ

The paper analyses influence that greenhouse gases emissions contained in exhaust gases of diesel engines render on formation of the greenhouse effect. The author shows that except СО2 in the total balance of greenhouse gases emissions it is necessary to consider also nitrogen oxides emissions that more aggressively than the carbon dioxide affect the air environment.

Establishment of the Reynolds Criterion for Ultrasonic Cleaning of Exhaust Gases of Internal Combustion Engines

Establishment of the Reynolds Criterion for Ultrasonic Cleaning of Exhaust Gases of Internal Combustion Engines

Advanced Exergy Scrutiny of a Dual-loop Organic Rankine Cycle for Waste Heat Recovery of a Heavy-duty Stationary Diesel Engine

In this paper, the normal exergy scrutiny (NES) and advanced exergy scrutiny (AES) of a waste heat recovery (WHR) system was performed. The proposed system contains a dual-loop organic Rankine cycle (DORC) which recovers the available waste heat of the intake air, exhaust gas, and coolant streams of a 12-cylinder heavy-duty stationary diesel engine. A well-known method of the AES called the thermodynamic cycle approach is utilized to determine each component exergy destruction parts namely exogenous/endogenous, unavoidable/avoidable, etc. Results showed that 59.04 kW from the 258.69 kW total exergy destruction rate of the system could be eliminated (22.82% of the total exergy destruction rate). The total avoidable exergy destruction part of the low-temperature loop accounts for 46.62 kW, which indicates that it requires more attention than that of the high-temperature loop by 12.42 kW. Furthermore, it is revealed that to enhance the overall productivity of the system, there is a relatively significant difference in priority order regarding the improvement of system components. The AES has proposed this ranking for improvement priority of components: condenser, expander 2, expander 1, respectively. While the NES has specified the priority as the evaporator 1, condenser, expander 2, respectively.

Influence of Combustion Chamber Design Parameters and Intake Environments on Spark Ignition Engine Performance and Exhaust Gas Emission

In the present paper, the effect of the combustion chamber design parameters on the improvement of combustion efficiency (the heat generated inside the combustion chamber) and the enhancement in the pollution rates (heat emissions) from a four-stroke, spark-ignition engine has been studied experimentally and theoretically. Two different programs, Gaseq and Ansys, were used to simulate the effect of the combustion chamber shape, turbulent kinetic energy, intake temperature, intake pressure, parity ratio, compression ratio, and engine speed on reducing specific fuel consumption in the engine, reducing carbon dioxide emissions, and increasing overall engine efficiency. The results showed increasing the intake temperature increased the amount of heat produced in the combustion chamber. This leads to increases in the overall efficiency of the engine, but leads to increasing the carbon dioxide and nitrogen oxide emissions. Increasing the intake pressure has a positive effect on the combustion temperature and pressure, but it has a negative effect on carbon dioxide and nitrogen oxides. Raising the pressure ratio improved the overall efficiency of the engine by increasing the combustion heat, but increasing specific fuel consumption and emissions. Also, increasing the engine speed above the permissible limit has an adverse effect on the spraying speed due to the piston speed being higher than the flame speed, which leads to a reduction in the engine brake torque. An increase in the compression ratio leads to higher fluid pressure and output capacity, but combustion methods occur. An increase in the kinetic energy of the turbulence leads to good combustion. A bowl in a piston has the highest rate of rotation and rotation compared to flat and hemispherical pistons. That is, the design of the cylinder head of this type leads to an improvement in the combustion efficiency and thus the efficiency of the engine.

Diagnostic Information Analysis of Quickly Changing Temperature of Exhaust Gas from Marine Diesel Engine Part I Single Factor Analysis

Abstract In this paper, attention was paid to the problem of low controllability of marine medium- and high-speed engines during operation, which significantly limits the parametric diagnosis. The measurement of quickly changing temperature of engine exhaust gas was proposed, the courses of which can be a source of diagnostic information. The F statistic of the Fisher-Snedecor distribution was chosen as a statistical tool. Laboratory tests were carried out on the bench of a Farymann Diesel engine. The tests consisted of introducing the real changes in the constructional structure of the considered functional systems of the engine. Three changed parameters for the structure were reviewed: the active cross-sectional area of the inlet air channel, injector opening pressure and compression ratio. Based on the recorded plots of the quick-changing temperatures of the exhaust gases, three diagnostic measures were defined and subjected to statistical tests. The following data were averaged over one cycle for a 4-stroke piston engine operation, (1) the peak-to-peak value of the exhaust gas temperature, (2) the specific enthalpy of the exhaust gas, and (3) the rate of increase and decrease in the values for the quick-changing exhaust gas temperature. In this paper will present results of the first stage of the elimination study: the one-factor statistical analysis (randomised complete plan). The next part will present the results of the second stage of studies: two-factor analysis (block randomised plan), where the significance of the effect of changing the values of the structure parameters on the diagnostic measures was analysed in the background of a variable engine load.

Application of CFD and ANN in Predicting the Flow Nature of Flue Gas in the Catalytic Converter

The main objective of this research is to improve the performance of the catalytic converter by achieving uniform flow distribution of petrol engine exhaust gas using a distributor plate in the upstream section. The flow analysis in the catalytic converter is conducted using computational fluid dynamics (CFD) Solid works 2017 simulation software. Totally, flow simulation is carried out for twelve different cases. It has been observed that a 140 mm diffuser and distributor plate positioned 117 mm from the entrance delivers the optimal flow trajectory. This catalytic converter highly exhibits a non-linear correlation between the input and output variables. Results of such simulation study are then considered as an input for artificial neural network (ANN) model, an artificial intelligence (AI) technique. Results predicted by the ANN model are compared with CFD output. Compared outputs are in good agreement with each other. To sum up, we conclude that by introducing the distributor plate in the flow regime of the conventional catalytic converter, we can accelerate the rate of uniform flow distribution.

Assessment of the Actual Toxicity of Engine Exhaust Gas Emissions from Euro 3 and Euro 6 Compliant Vehicles with the Bat-Cell Method Using in Vitro Tests

Assessment of the Actual Toxicity of Engine Exhaust Gas Emissions from Euro 3 and Euro 6 Compliant Vehicles with the Bat-Cell Method Using in Vitro Tests

ZrO2 Nanolif Oksijen Sensörünün Performans Değerlendirmesi

An alternative oxygen sensor to conventional ZrO2 based automotive oxygen sensors (COS) was successfully manufactured. ZrO2 nanoparticles were used as base material and nanofibers were fabricated via electrospinning using polyvinyl alcohol and ZrO2 solution (ZrO2+PVOH) to obtain active surface of the sensor where the engine exhaust gas interacts and chemisorption reactions take place prior to calcination process of nanofibers at 700 oC. Thanks to operating temperature control and high surface/volume ratio of nanofibrous structure, the ZrO2+PVOH nanofibrous sensor demonstrated similar performance with COS under increasing exhaust gas percentage (until 50-60%) along with increasing operating temperature conditions. For ZrO2+PVOH nanofibrous sensor, maximum sensing performance (Ra/Re) of 7.24 was achieved at sensor operating temperature of 700 oC and exhaust gas concentration of 50% whereas it was 8.11 for EOS under same conditions. The ZrO2+PVOH nanofibrous sensor performed acceptable performance throughout wider operating temperature range (270-900 oC) compared to conventional COS. Though an average of 15% reduction in sensing performance was observed for ZrO2+PVOH nanofibrous sensor, the promising results of this alternative oxygen sensor will be a good guide for more comprehensive future works focusing on oxygen sensors with very rapid response-recovery time and light-off capability.

Monitoring and neutralization of exhaust gases of internal combustion engines

Monitoring and neutralization of exhaust gases of internal combustion engines