ЗМЕНШЕННЯ ВИКИДІВ ОКСИДІВ АЗОТУ З ВІДПРАЦЬОВАНИМИ ГАЗАМИ СУДНОВИХ ДИЗЕЛІВ

The problem of air basin pollution of the World Ocean with harmful emissions from the exhaust gases of marine diesel engines is primarily associated with the creation of highly efficient technologies for the neutralization of nitrogen oxides NOx on exhaust gases from a diesel engine. Emissions of harmful substances from the combustion of marine fuels are limited by international atmospheric protection programs and the requirements of the International Maritime Organization (IMO). The requirements relate to almost all groups of harmful emissions in marine engines and the more stringent of them are primarily related to nitrogen oxides NOx and sulfur oxides SOx. To reduce harmful emissions from exhaust gases into the environment, scientists and world engine leaders use and suggest various methods for reducing the content of harmful substances in exhaust gases. The implementation of new standards in the areas of further improvement of the working process, the use of alternative fuels, fuel, and air additives, as well as selective catalytic reduction systems do not preclude further development of scientific research in the field of exhaust gas cleaning. One of the promising ways in environmentalizing marine internal combustion engines is the neutralization of harmful substances in exhaust gases through particular gas recirculation (EGR-technology). However, the use of such techniques conflicts with the engine's energy efficiency. In the work presented, the scheme-design solution of the exhaust gas recirculation system with using the heat of recirculation gases by an ejector refrigeration machine for cooling the air at the intake of ship's main engine is proposed. The effect of using the heat of recirculation gases for cooling the air at the intake of the engine is analyzed taking into account the changing climatic conditions for a particular vessel's route line. It is shown that the use of an ejector refrigeration machine reduces the air temperature at the entrance of the main engine by 5…15 ° С, which reduces the specific fuel consumption. This reduces emissions of harmful substances when the engine is running with recirculation of gases.

In this paper, an experimental study evaluating the effect of exhaust gas recirculation (EGR) and liquefied petroleum gas (LPG) onboard systems attached to a single cylinder DI diesel engine running with diesel is presented. Tests were performed at the minimum (1400 rpm) and maximum engine speeds (4100 rpm). The engine were tested under four different operating modes mainly; (a) standard test condition, (b) engine with EGR system, (c) engine with LPG system and (d) the engine with EGR and LPG onboard systems. Parameters that been measured during the tests are percentage of oxygen (O2) content, carbon monoxide (CO) emissions, carbon dioxide (CO2) and unburned hydrocarbon (UHC) emissions. Results show for the exhaust emissions, the engine with LPG onboard system emits higher CO and UHC emissions for both engine speeds. According to the experimental results it can be concluded that the use of EGR system increased the exhaust gas temperature and CO2emissions. While the engine with EGR and LPG onboard systems have influenced much on the increase in CO and UHC emissions for both engine speeds.

To achieve low nitrogen oxide (NO x) emissions and combustion reliability, the variation in the geometry of the exhaust gas recirculation (EGR) system should be optimized. However, the layout process essentially fixes the position of a conventional EGR system, and modifying the intake manifold geometry tends to be economically unjustifiable for a commercial engine. In the present study, two types of EGR system, namely ‘linked single’ and ‘individual’ EGR systems, are proposed and their performances are evaluated numerically. Parametric studies were performed using a three-dimensional numerical model to assess the mixing uniformity of the intake air and EGR gases. The distribution of the mixed gases into the four runners, which force the mixed gases into the four combustion cylinders, is predicted. Three different geometries of the EGR system are considered: single, side-feed individual, and top-feed individual configurations. These geometries reflect the means by which the EGR gases are supplied into the four cylinders. These three configurations are called cases A, B, and C respectively, and their corresponding detailed geometries are identified as A1 to A9, B1 to B17, and C1 to C10, which give a total of 36 computational runs. It was found that case A5 with a hole angle of 60° yielded the most optimal operating mixing and distribution condition. In general, the single systems were found to be superior to the individual systems, among which the top-feed system tended to be slightly more advantageous for mixing than the side-feed individual system owing to the symmetric supply of the top-feed system. The flow of the throttle-valve system, which controls the mass flowrate of the intake air, was used as the validation case; Hyundai-Kia Motor Co. provided the experimental data, which were compared with the computational results.

Nowadays one of the most urgent problems of creating modern combustion engines (ICE) is the problem of ecology. Ensuring environmental requirements is usually associated with the introduction of new structural elements or the modernization of existing structures, since practice shows that the use of traditional methods to reduce the toxicity of exhaust gases, leads to a gradual deterioration in the fuel economy of the engine. This article discusses the use and development of an exhaust gas recirculation system for a transport diesel as the most effective means of reducing NOx emissions into the environment. On the example of expert data, the experience of using exhaust gas recirculation systems in diesel engines is considered, and their main advantages and disadvantages are given. The use of «cooled» exhaust gas recirculation is more preferable than «uncooled», since the filling of the cylinders with an air charge improves, and lower gas temperatures during the combustion period are provided, thereby reducing the amount of NOx generators. It is also noted in the work that when a cooled exhaust gas recirculation system is used in conjunction with optimization of engine design and adjustment parameters, NOx emissions are reduced with minimal deterioration of the engine's power and economic parameters. On the example of research and simulations on the testbench of the transport engine 8ChN 12/13, the efficiency of the exhaust gas recirculation system on diesel has been estimated and all the necessary data was provided. Due to the optimization of the adjusting parameters and the developed model of the exhaust gas recirculation system, it was possible to achieve 46 % reduction in NOx emissions. It has been shown experimentally that the use in a diesel engine of a theoretically developed organization of working processes with the use of recirculation of exhaust gases and the characteristics of controlling the main adjustments of the combustion process is advisable.

Parametric investigation of a large marine two-stroke diesel engine equipped with exhaust gas recirculation and turbocharger cut out systems

The paper deals with the issue of determining the fuel efficiency and toxicity of exhaust gases of power equipment of road machines operating in traction modes, namely, plow and plow-brush snowplows based on a pneumatic wheeled tractor. The object of research is fuel efficiency and toxicity of exhaust gases of power equipment. The purpose of the study is to experimentally determine the external speed characteristics of a 4Ч11,0 / 12,5 diesel engine (D-240, D-241, D-242, D-243 families), namely: maximum power Ne, maximum torque Mк; hourly consumption of fuel Gпал and air Gпов, specific effective fuel consumption ge; concentrations of harmful substances in the exhaust gases: carbon monoxide CO, hydrocarbon compounds CmHn, nitrogen oxides NOx and opacity N of the exhaust gases. The paper presents the results of experimental studies to determine the energy performance (maximum power Ne and maximum torque Mк) of a diesel engine (4Ч11,0/12,5 (D-242)) of power equipment; fuel efficiency indicators (hourly fuel consumption Gпал and specific effective fuel consumption ge); hourly air consumption Gпов; concentrations of harmful substances in the exhaust gases: carbon monoxide CO, hydrocarbon compounds CmHn, nitrogen oxides NOx and opacity N of the exhaust gases. Which are obtained with the position of the fuel supply control, which corresponds to the maximum fuel supply from the diesel crankshaft speed. The above indicators were determined at standard diesel fuel supply settings. Based on the obtained external speed characteristics Ne, Mк, Gпал, ge, Gпов, CO, CmHn, NOx and N, mathematical (polynomial) dependencies were determined, which are described from the speed of the diesel crankshaft, and their adequacy was checked. The studies carried out made it possible to determine the main direction of increasing fuel efficiency and reducing emissions of harmful substances of a diesel engine.

The analysis of the development of electric vehicles in Ukraine. The quantitative indicators of the growth of electric vehicles in the world are considered. The world leaders on the creation and introduction of electric vehicles have been identified. The main provisions of state support of electric vehicles market in Ukraine are outlined. Problem. Today, the problem of ecology in major cities and near highways remains acute. Emissions of harmful substances from exhaust gases from cars with internal combustion engines continue to grow and their share in emissions of harmful substances of the transport complex is 89%. Demands to the environmental safety and fuel economy of cars with internal combustion engines are increasing every year, and this forces theautomakers to seek unconventional solutions to this problem. The most effective direction in solving these problems is the use of electric drive in the construction of the car. Goal. The goal is analysis of the marketof eleсtromobiles in Ukraine over the past 6 years and definition of world leaders in creation and implementation of electric vehicles. In order to achieve this goal, the following tasks need to be solved: to carry out an analysis of the market of electric vehicles in Ukraine; to consider quantitative indicators of the growth of number of electric vehicles in Ukraine and in the world; to identify world leaders in creation and implementation of electric vehicles; to reveal the main provisions of state support of the market of electric vehicles in Ukraine. Results. This article analyzes the data for the last 6 years, which show a positive trend in the growth of registered electric vehicles in Ukraine. Maintaining benefits for the import of electric vehicles, the abolition of licenses for the sale of electricity for charging stations, the development of the concept of the infrastructure of charging stations contribute to the development of the infrastructure of charging stations and increase the number of registered electric vehicles. However, today there are a number of problems. To solve the problem of the introduction of electric vehicles, it is necessary to organize the state and investment support for the developmentand use of electric vehicles in the transport system of Ukraine, create the infrastructure of charging stations, form scientific and technical centers for the development and production of electric vehicles, equalize the cost of an electric vehicle with a car with the engine of the same class, impose restrictions on the use of cars with ICE in the city centers

To meet the stringent nitrogen oxides emissions regulations, the recent marine two-stroke engines are equipped with exhaust gas recirculation (EGR) systems. Crossing the boundaries of exhaust control areas requires switching between the engine operating modes associated with the activation or deactivation the EGR system, which imposes challenges to the engine operation. This study aims to develop and numerically test effective control strategies for improving the mode switching of marine two-stroke engines with EGR systems. The investigated engine dynamic model is developed by integrating a zero-dimensional thermodynamic model developed in GT-POWER and the control model developed in MATLAB/Simulink. This model is first validated against the experimentally measured engine performance parameters, and subsequently employed to simulate the engine dynamic operation with mode switching. The simulation results are assessed to quantify the impact of several control strategies on the engine performance. The derived perrformannce parameters time variations demonstrate that the deactivation of the EGR branch and the small engine–turbocharger result in exceeding the manufacturer limits at high loads and increasing the fuel consumption. The proposed load-based control strategies, which employ load thresholds and time delays for the control of the EGR and turbocharging systems activation/deactivation, are proved effective, as the engine performance parameters are retained within their limits and fuel consumption penalties are minimised. This study provides insights for developing the control of the marine engines after-treatment systems, hence contributing towards enhancing shipping sustainability.

Potential for onboard hydrogen production in an direct injection ethanol fueled spark ignition engine with EGR

Exhaust Gas Recirculation (EGR) is technology to reduce NO X emission of diesel engine. This technology could circulate some exhaust gas into the combustion chamber. The adiabatic combustion temperature could decrease and reduce the reaction of oxygen in nitrogen. This method could inhibit the formation of NO X during the combustion process because NO X formation reactions occur at high temperatures. EGR has some effects such as decreased engine performance, SFOC increases and changes in the combustion process. In order to suppress the negative impact, the research carried out by replacing the EGR valve using a type angle globe valve. Experiments conducted using a single cylinder diesel engine YANMAR type TF85-MHDI. The result obtained in this study is the emission of NO X can be reduced up to 15.6 g/kWh or 44.2% of the engine condition without EGR. The experimental results indicate that the use of angle globe EGR valve can reduce the SFOC up to 35.29 gr/kWh. Results of power, torque and BMEP also better compared EGR standard. While in the combustion process showed that the use of EGR valve angle globe causing peak of combustion pressure becomes lower and the Rate of Heat Release (ROHR) is lowered.

EGR modeling and fuzzy evaluation of Low-Speed Two-Stroke marine diesel engines

During the operation of ships, millions of tons of nitrogen oxides NOx, sulfur oxides SOx, soot, heavy metal compounds, and water vapor are emitted into the atmosphere every year. The exhaust gas recirculation (EGR) technology reuses engine exhaust gases during combustion to reduce the amount of oxygen at the engine cylinder’s inlet and reduce the amount of NOx rejected. The exhaust gas recirculation temperature is an important factor in allowing a higher percentage of the exhaust gas recirculation. Caused by higher loads, higher exhaust gas temperatures limit the higher exhaust gas recirculation coefficients. The application of the EGR system of the ship’s diesel engine using the heat of the gases by the ejector and absorption chillers for cooling the engine inlet air is proposed to cool the air entering the 6G50ME-C9.6 marine engine. A circuit design solution was proposed using the heat of recirculation gas (RG) by an ejector chiller (ECh) and absorption chiller (ACh) in the EGR system. The analysis has been made of using the heat of RG to cool the air entering the engine. The effect has been analyzed, considering changes in climatic conditions on the Odessa-Shanghai route for a dry cargo vessel. It has been found that the use of an exhaust gas recirculation system using heat RG for cooling engine intake air by ECh and ACh reduces the temperature of the air entering the engine. The temperature drops by 5–15 °C, which in turn reduces the specific fuel consumption (SFC) by 0.6–1.8 g/(kW \(\cdot\) h). Also, the amount of harmful substances formed during engine operation decreases SOx by 10–14%; NOx by 25–35%.

The purpose of the conducted research is to improve the method of calculation and determination of both fuel consumption and emissions of harmful substances from the engines of vehicles converted to run on alternative fuel. The article examines the peculiarities of determining fuel consumption and emissions of harmful substances from the engines of vehicles converted to run on alternative fuel. The method of calculating fuel consumption and environmental indicators of vehicles running on alternative fuel has been developed, which is based on a systematic combination of methods and means of obtaining information about the processes and operating conditions of vehicles, which are obtained as a result of remote monitoring of parameters of the technical condition of vehicles. The peculiarity of the method is that it involves the joint use of both existing methods and means of obtaining information on vehicle operation processes, engine thermal parameters, fuel consumption and emissions of harmful substances. This method of calculating both fuel consumption and emissions of harmful substances in the exhaust gases of a vehicle with engines converted to run on gas fuel allows to evaluate the efficiency of the operation of the vehicle engine thanks to the analysis of current and total values of indicators of fuel consumption and emissions of harmful substances in processes pre-launch and post-launch thermal preparation and during its movement in the driving cycle and during movement on the route.
 In the work, the authors proposed to use the fuel consumption coefficients for both liquid and gaseous fuels to determine the fuel consumption in operating conditions, which make it possible to abstract from the dimensions. For the vehicle engine cooling system, it is proposed to measure fuel efficiency and other environmental indicators according to existing methods in several modes of heating the coolant up to a temperature of 50°C.

<div class="section abstract"><div class="htmlview paragraph">Water vapor is, aside from carbon dioxide, the major fossil fuel combustion by-product. Depending on its concentration in the exhaust gas mixture as well as on the exhaust gas pressure, its condensation temperature can be derived. For typical gasoline engine stoichiometric operating conditions, the water vapor dew point lies at about 53 °C. The exhaust gas mixture does however contain some pollutants coming from the fuel, engine oil, and charge air, which can react with the water vapor and affect the condensation process. For instance, sulfur trioxide present in the exhaust, reacts with water vapor forming sulfuric acid. This acid builds a binary system with water vapor, which presents a dew point often above 100 °C.</div><div class="htmlview paragraph">Exhaust composition after leaving the combustion chamber strongly depends on fuel type, engine concept and operation point. Furthermore, the exhaust undergoes several chemical after treatments. The transformation of pollutants in these components drastically affects the composition of the possible exhaust condensate, which can for instance shift its pH-value from acidic to alkaline.</div><div class="htmlview paragraph">Detailed analysis of these condensable exhaust components and understanding of condensate composition becomes of increasing importance with the growing relevance of exhaust gas recirculation (EGR) cooling and when thinking of exhaust gas as a potential water source. In spite of this, the complexity of the exhaust condensation process is, especially with regard to gasoline engines, a field of relatively low focus up until now. The goal of this study is to present a theoretical analysis of the thermodynamics of gasoline engine exhaust condensation including an experimental data based validation. Through investigation of the influence of the air/fuel ratio, pollutant concentrations, and temperature conditions, an improved understanding of the condensation process is gained.</div></div>

Effect of operating parameters on performance and emissions of a diesel engine fueled with ternary blends of palm oil biodiesel/diethyl ether/diesel by Taguchi method