Cylinder-piston Group Research Articles

Method for constructing experimental-theoretical models for control of heat stress of automotive diesels by indirect parameters

The article proposes a method for constructing experimental-theoretical models for monitoring the heat tension of parts of the cylinder-piston group of automotive diesel engines by indirect parameters. An example of constructing an experimental-theoretical model of a specific engine is given; the conditions for the application of experimental theoretical models for solving practical problems are formulated. Keywords: automotive diesel engine, cylinder-piston group, heat intensity, experimental - theoretical model, indirect parameters

Influence of Cavitation on the Working Surfaces of the Cylinder–Piston Group in a Diesel Engine during Maintenance

Influence of Cavitation on the Working Surfaces of the Cylinder–Piston Group in a Diesel Engine during Maintenance

Analysis of mechanical energy losses in marine diesels

The object of research is marine diesel engine oils, which provide lubrication, cooling and separation of friction surfaces. The subject of the research is the process of ensuring minimum mechanical losses in marine diesel engines. A problematic point in ensuring the lubrication of the cylinder-piston group and motion bearings is the lack of analytical and experimental studies that establish the relationship between the structural characteristics of engine oils and mechanical losses arising in marine internal combustion engines. The degree of orientational ordering of molecules and the thickness of the boundary lubricating layer are considered as the structural characteristics of engine oils. The determination of these values was carried out using the optical method based on the anisotropy of the light absorption coefficient by the boundary lubricant layer and the isotropic volume of the liquid (engine oil). The assessment of the level of mechanical losses arising in marine diesel engines was carried out according to an indirect indicator – the overshoot of the rotational speed and the time to reach the steady state of operation in the event of a change in load. It has been experimentally established that for engine oils used in marine internal combustion engines, the thickness of the boundary layer can be 15–17.5 µm. Motor oils, which are characterized by a higher ordering of molecules and a thickness of the boundary lubricant layer, ensure the flow of transient dynamic processes with less overshoot and a shorter transient time. This ensures the level of minimal mechanical losses occurring in marine diesel engines. The technology for determining the structural characteristics of engine oils can be used for any type and grade of oil (mineral or synthetic; high or low viscosity; used in both circulating and cylinder lubrication systems). The method of indirect assessment of mechanical losses of marine diesel engines can be used for any types of internal combustion engines of ships of sea and river transport (low-, medium- and high-speed; as well as performing the functions of both main and auxiliary engines).

Improvement of diagnostics of the cylinder-piston group of internal combustion engines

The paper considers the study of the dependence of the number of leaks of compressed air from the over-piston space of an internal combustion engine on the wear of its cylinder-piston group. To conduct this study, a special pneumatic tester was made that allows measuring leaks at pre-established characteristic points inside the cylinder liner. The most common engine operation malfunctions affecting the tightness of the combustion chamber were modeled. As a result of the study, the following patterns were revealed. With an increase in the ovality and taper of the worn sleeve of the KamAZ 740 engine, the readings of the pneumatic tester decrease from 4.2 kg/cm2 to 3.4 kg/cm2, when the rings are coked from 3.5 kg/cm2 to 3 kg/cm2, and when they break from 2 kg/cm2 to 1.5 kg/cm2. For the engine sleeve of the ZMZ 53, the readings of the pneumatic tester are reduced from 3.7 kg/cm2 to 3.4 kg/cm2, when the rings are coked from 3.3 kg/cm2 to 3 kg/cm2, and when they are broken from 1.8 kg/cm2 to 1.35 kg/cm2 When the valve leak increases from 10 mm2 to 20 mm2, the instrument reading drops sharply to 0.

Cyclic Indentation Method Applied to Evaluating Surface Degradation of Cylinder-Piston Group Parts

Cyclic Indentation Method Applied to Evaluating Surface Degradation of Cylinder-Piston Group Parts

Система вібромоніторингу ДВЗ маломірних суден на базі Arduino

The problem of current monitoring of the state of an internal combustion engine is especially relevant for water transport. Usually, in complex systems for monitoring the state of the cylinder-piston group (CPG) of cargo ships, many indicator indicators are used, such as temperature, pressure, vibration. For small boats, such a complex system with integrated sensors is redundant. The purpose of this study is to develop a system for vibration monitoring of the state of internal combustion engines of small vessels based on the open-source platform Arduino Uno with data transfer to cloud storage. In the article, the authors have developed a connection diagram and software for a vibration monitoring system for internal combustion engines of small vessels. The theoretical basis of the developed system is based on the FFT analysis technique based on the fast Fourier transform. The developed design is based on the Arduino Uno microcircuit. The data transfer takes place using the ESP8266 Wi-Fi module for real-time output on the Django server and storage in Google Sheets. The choice of such a system is due both to the need for the existence of a system for the current display of indicator parameters with the establishment of the nature of malfunctions and signaling of critical operating modes, and the need for the accumulation of scientific data for researching the operating mode of the engine. It will be useful for scientists and designers of ICEs of small vessels. It has been established that the use of the modular Arduino system will make it possible to vary the properties of the vibration monitoring system within a wide range by using various types of sensors (KY-038 and LM393). The method of data transmission of the vibration monitoring system at the software level has been improved by using software blocks from three open-source projects based on Arduino. The developed scheme can be developed for use in vehicles, as well as monitoring of other types of engines. This can become the basis for the accumulation of data, which will make it possible to more accurately diagnose deviations in the operation of the internal combustion engine of small vessels based on general statistics, and not only data from one engine, as in similar systems for cargo ships.

Constructive possibilities of increasing the tightness and wear resistance of the cylinder-piston group of the internal combustion engine

The processes of wear of the tribocouplings of the cylinderpiston group (CPG) of the internal combustion engine are investigated. Design solutions are developed that increase the tightness and wear resistance of the CPG parts. Keywords: cylinder-piston group, internal combustion engine, wear, tightness, wear resistance, running-in. vakochenov@yandex.ru

THE CONCEPT OF COMBUSTION PROCESS ORGANISATION IN A BOXER TWO-STROKE DIESEL ENGINE AT A HIGH LEVEL OF BOOSTING

Based on the analysis and synthesis of previously performed theoretical and practical studies, the paper proposes a concept of combustion process organization in a boxer two-stroke diesel engine at a high level of boosting. Such diesel engines are produced in Ukraine and are widely used in land, sea and rail transport, as diesel generator plants. The implementation of this concept will ensure the reduction of the thermal stress of the cylinder piston group for these diesel engines, while improving fuel efficiency.
 The features of the organization of the working process in a boxer two-stroke diesel engine are briefly considered. The contribution of Ukrainian, Russian and American scientists to the development and improvement of their mixing efficiency is noted.
 Following the purpose of the research, which determines the choice of directions for the development and implementation of technical solutions for the simultaneous reduction of fuel consumption and thermal tension of the cylinder-piston group when forcing a boxer two-stroke diesel engine, it is proposed to use the amount of released heat as a criterion for evaluating the quality of combustion.
 Based on the results of earlier studies, conceptual foundations for increasing the efficiency of the combustion process of a highly boosted boxer two-stroke diesel engine have been developed, which are directly related to the air supply, fuel supply, the rationale for choosing the shape of the combustion chamber are determined by the amount of heat released during combustion and the nature of its change in the crankshaft rotation angle.

Environmental performance of the Volkswagen 1,4 engine in the process of its operation on biogas

In recent years, Ukraine and the world have seen a steady increase in the use of compressed natural gas (LNG) in cars. The main reason for such attention to gaseous motor fuel is its low cost compared to gasoline and diesel fuel. This is also facilitated by the extensive network of autogas filling compressor stations (CNG stations) ofUkrtransgaz, which today is about 150 stations and is constantly growing. Today, the network of CNG stations in the country is used by 35,000 cars, which allows Ukraine to rank seventh in the world in terms of the number of cars running on LNG. The use of methane-based natural gas as an alternative fuel in Ukraine has long begun. Road transport is actively switching to this gas. Currently, the country is conducting a powerful advertising campaign to convert cars from conventional fuel to natural gas. The economic benefits of such a transition are obvious. Natural gas turned out to be almost twice cheaper than propane, which is much cheaper than gasoline. Unlike gasoline and diesel fuel, natural gas does not contain toxic impurities and additives, has a wide range of ignition. Exhaust gases from natural gas engines contain a small amount of normalized harmful emissions. LNG, including biogas, burns more slowly than gasoline, reducing the load on the cylinder-piston group, the engine runs "softer" and quieter. In total, these factors provide double (and more) savings in operating costs, extend the life of the engine by 30-40%, oil and spark plugs - twice, and as a result significantly reduce repair costs. Optimization of the working process of the engine running on gas (increasing the degree of compression of the engine to 10-11; installation of a modern ignition system with modified, optimized for gas fuel characteristics at maximum and variable engine speeds) allows to ensure maximum engine power while maintaining efficiency and environmental parameters. high modern level.

ДЕТОНАЦІЙНО-ГАЗОВЕ ЗМІЦНЕННЯ ДЕТАЛЕЙ ДВИГУНІВ ВНУТРІШНЬОГО ЗГОРАННЯ

The paper deals with improving the reliability and durability of parts of the cylinder-piston group of internal combustion engines. Strengthening of machine parts is possible through the use of special production processes. Modern materials and coatings must be able to meet high operating temperatures and loads.Chrome plating, boriding and ion-plasma spraying do not meet the established quality requirements. The aluminum piston suffers damage in the head area. This manifests itself in the accumulation of cracks, channels, and traces of alloy washout. In addition, due to heating, the strength of the aluminum alloy becomes worse more than 2 times.It is proposed to create and use a coating that would withstand operating temperatures of more than 2000°C, as well as shock-pulsating loads. A detonation-gas spraying method is proposed. It is characterized by the versatility of materials and can be applied to polymers and to refractory ceramics, as well as to any metals and alloys.The deposited particles have high kinetic energy. The coating is characterized by high strength, which reaches 180 ... 200 MPa, hardness HRCe 60, and minimal cracks. The temperature effect during spraying on the workpiece is negligible. A sequence of preparatory operations is proposed. The piston and glow ring on the UN-102 detonation-gas installation were to be strengthened. A manipulator was used that uses the energy of the installation shot.The resulting surfaces are characterized by a regular macrostructure (waviness). A nickel-aluminum alloy was applied. Coating thickness was about 150 ... 270 microns, hardness was of HV 550, adhesion to the base eas of 94 ... 100 MPa. The results of studies on the parts of the cylinder-piston group showed a decrease in operating temperatures due to the running-in of the coating and high-quality sealing of the combustion chamber.The durability of the rings is 1.6·106…2.3·106, which indicates a significant increase in fatigue resistance and service life. The proposed technology is suitable and recommended for implementation in mass production

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЯ ПНЕВМОПЛОТНОСТИ ЦИЛИНДРОПОРШНЕВОЙ ГРУППЫ ДИЗЕЛЬНОГО ДВИГАТЕЛЯ

Reducing the leakproofness of the working volume of the cylinder due to wear of the cylinder piston group or other reasons leads to interruptions in the engine work. (Research purpose) The research purpose is in studying the dependence of the pneumatic leakproofness of the cylinder-piston group of a diesel engine on the position of the piston and the pressure of the air supplied to the cylinder. (Materials and methods) When diagnosing the cylinder-piston group, various devices are used, including pneumatic testers. This test method does not provide reliable information about the reasons for the decrease in air density and since the engine cylinders wear out unevenly, the diagnostic process must be performed at different positions of the piston. (Results and discussion) During the study of pneumatic tightness, it was found that the leakproofness of the worn cylinder-piston group in the zone of the upper dead center at the minimum pressure of the supplied air was 12.8 percent lower than in the rest of the cylinder. With an increase in pressure, the difference in leakproofness decreased to 6.3 percent. Authors confirmed the hypothesis of the dependence of the leakproofness of the worn cylinder-piston group on the position of the piston, which allows us to more accurately determine the cause of the violation of the leakproofness of the cylinder. The low pressure of the supplied air shows a greater informative value of the measurement due to a wider change in the air density in the upper dead center zone compared to the middle part of the cylinder and a smaller change in the density of the air flowing through the gaps of the cylinder-piston group. (Conclusions) In order to increase the degree of accuracy of testing the pneumatic density of the cylinder-piston group, measurements must be carried out several times at different pressures of the supplied air.

Numerical and experimental study on fluid compressibility in a two-stage reciprocating pump-compressor

• Liquid piston velocity decreases with increasing pressure due to liquid compressibility. • Liquid piston brings the compression process closer to thermodynamically efficient. • Liquid expansion leads to a decrease of the pump volumetric efficiency. • Pressure ratio has the greatest impact on a decrease of liquid layer height and velocity. Currently, multistage (two and three-stage) reciprocating compressors are used to compress the gas to medium and high pressures. One of the promising operating principles of such machines is a preliminary compression in a single-stage piston compressor and a final gas compression in a working cavity with a liquid piston. The main advantages of a compressor using a liquid piston are intensive cooling of the compressed gas and the absence of leaks and leakages in the cylinder-piston group. This makes it possible to increase the indicated isothermal efficiency and actual volumetric efficiency. The article considered the effect of liquid compressibility in the two-stage piston hybrid positive-displacement machine with a liquid piston. We developed a calculus methodology for the liquid compressibility during gas compression in the second stage of the compression section based on the volume conservation equation and Hooke's law. Numerical simulation showed that the degree of pressure ratio had the greatest impact on the relative decrease in the height and velocity of the liquid layer. We found that the relative decrease in the liquid layer height was within 1%. The relative decrease in the liquid piston velocity was within 5%. We carried out the experiment and validation of the results with a numerical simulation, which reflected the mathematical model validity. The model worked correctly based on an estimated experimental error. The parametric analysis of the test model showed the influence of the main working cavity parameters. The discrepancy in determining the dynamic pressure in the machine cavities conducting theoretical and experimental studies is within 10–15%. The paper analysed the liquid piston compressibility influence on the thermodynamic efficiency of the compression process and compressor performance.

The use of light fractional composition fuels in the electric flame jet of a diesel engine

In recent years, there has been an increased interest in the development of the polar territories of our planet. A large number of minerals on land and in the shelves attracts the attention of our contemporaries. Development of these territories with a harsh climate is possible by using modern vehicles and mechanisms that ensure the exploration of sediment layers, extraction of deposits, transportation of rocks and raw materials. The most common mode of transportation in these conditions are motorized vehicles. One of the most important aspects in the operation of automotive equipment in conditions of temperatures below freezing point in a cold climate is the startup of the diesel engine after a long period of parking. The industry produces auxiliary equipment. In this regard, heat generators are widely used. There are individual and group heaters of various types, including flame and infrared heaters that can provide support in the pre-starting procedure. In addition, there are means to facilitate the start-up. The reliable start of a diesel engine is influenced by factors such as the temperature of the air charge, the operating torque of the crankshaft, the conditions of fuel spraying, the activity of heat exchange processes and the tightness of the mating of the cylinder-piston group parts. The use of fuels of light fractional composition with an electric flame jet or the so-called gas-electric flame jet can constitute an effective solution to the problem.

Development and Research of Crosshead-Free Piston Hybrid Power Machine

This article considers the development and research of a new design of crosshead-free piston hybrid power machine. After verification of a system of simplifying assumptions based on the fundamental laws of energy, mass, and motion conservation, as well as using the equation of state, mathematical models of the work processes of the compressor section, pump section, and liquid flow in a groove seal have been developed. In accordance with the patent for the invention, a prototype of a crosshead-free piston hybrid power machine (PHPM) was developed; it was equipped with the necessary measuring equipment and a stand for studying the prototype. Using the developed mathematical model, the physical picture of the ongoing work processes in the compressor and pump sections is considered, taking into account their interaction through a groove seal. Using the developed plan, a set of experimental studies was carried out with the main operational parameters of the crosshead-free PHPM: operating processes, temperature of the cylinder–piston group and integral parameters (supply coefficient of the compressor section, volumetric efficiency of the pump section, etc.). As a result of numerical and experimental studies, it was determined that this PHPM design has better cooling of the compressor section (decrease in temperature of the valve plate is from 10 to 15 K; decrease in temperature of intake air is from 6 to 8 K, as well as there is increase in compressor and pump section efficiency up to 5%).

ПОВЫШЕНИЕ НАДЕЖНОСТИ ЦИЛИНДРОПОРШНЕВОЙ ГРУППЫ МАЛООБОРОТНЫХ ДВИГАТЕЛЕЙ С ПРИМЕНЕНИЕМ ДИАГРАММ ПАРЕТО

The article analyzes the main methods of increasing the reliability of operation of the cylinder-piston group currently used for the repair of the main power plants of sea vessels by ship repair plants in Ukraine, as well as abroad in many countries of the world. Improving the reliability of the main power plant of a sea vessel currently deserves special attention, and the importance of solving these problems is confirmed by a number of state, industry and other programs and decrees highlighting promising areas, one of which is to ensure reliable operation of the main power plant of a sea vessel. No matter how long low-speed engines are used, they have to be properly maintained, repaired by trained and qualified personnel who is capable of diagnosing a broken parts of the mechanism. The reliability of the engine must be maintained constantly at all these stages since the safety of the navigation of the vessel depends on the quality of the repair work, which in turn is controlled by the international maritime organization (IMO). The durability of the engine depends on the choice of the material of the parts, the method of obtaining the blanks, adherence to the manufacturing technology of the parts, assembly of the assembly, the quality of fuel and oils, modern and high-quality service. The high level of quality maintenance and operation of the unit, in accordance with the standards and requirements of the manufacturer, affects the durability of the parts of the cylinder-piston group, which are in severe operating conditions, namely, high temperature, pressure, and the presence of a corrosive environment. Therefore, these parts must have a given wear resistance, heat resistance, and corrosion resistance. Keywords: defect, failure, durability, reliability, cylinder-piston group, low-speed engines, Pareto diagram, Isikawa diagram.

Improving diagnostics of the cylinder-piston group by pneumatic testing

The task of authors research was to determine the emerging leaks when compressed air is supplied to the above-piston space under pressure of 4, 5 and 6 kgf / cm2, respectively.
 To obtain more reliable results, measurements of the leakage of the above-piston space by pneumatic testing should be performed three times. The deterioration of this tribo-coupling should be assessed by the average values of the obtained values. In order to identify the analytical relationships between the readings of the pneumotester and various types of cylinder malfunctions, it is necessary, to simulate during the experiment the malfunctions most often encountered during ordinary engine operation that affect the tightness of the combustion chamber.
 The planned experimental studies were carried out in strict accordance with the tasks and included three stages.
 The first stage included the collection and analysis of statistical data on the dependence of engine pneumatic testing indications on various types of cylinder-piston group (CPG) malfunctions during ordinary operation, as well as pneumatic testing of engine cylinders undergoing major repairs and their CPG micrometer size. At the second stage, an experiment to simulate malfunctions on an experimental setup and on a working engine, as well as to determine the influence on the readings of the pneumatic tester of the ratio of leaks in the piston ring sleeve interface was carried out. The third stage included the processing of statistical data, processing of the data obtained directly during the experiment with the introduced CPG malfunctions and the processing of the data obtained when determining the influence of the leakage ratio in the piston ring sleeve interface on the readings of the pneumatic tester.

Processes of mixture formation, ignition and combustion of a diesel engine

One of the most significant concepts of deep restructuring of the economic mechanism of the Republic of Uzbekistan is the creation of an integral, effective and flexible system of economic management and the implementation on this basis of a program to improve the technical level and quality of machines. The car park of our country is more replenished with vehicles with diesel engines. The development of contemporary diesel engine building is proceeding by forcing engines: increasing the average effective pressure and speed. Therefore, high reliability and service life, fuel efficiency and environmental performance are the basic criteria for their quality. Forcing diesel engines leads to an increase in thermal and mechanical loads on the basic parts of the cylinder-piston group (CPG) (piston, liner and cylinder head), a significant increase in their temperature, as well as the temperature of piston rings and valves. Overheating of parts is accompanied by the formation of temperature fields with a pronounced uneven temperature distribution and, as a result, an increase in thermal stresses with a simultaneous deterioration of the mechanical properties of the material, the formation of cracks and, finally, the destruction of the part. In this regard, the task of protecting parts from excessive exposure to high thermal loads from the working fluid becomes urgent, or, in other words, the task of creating a diesel engine with reduced heat removal from the working fluid.

ЭФФЕКТИВНОСТЬ РЕГУЛИРОВАНИЯ УРОВНЯ МАСЛА В АВТОТРАКТОРНЫХ ДИЗЕЛЯХ

Improving the reliability of tractor engines is an important task for the country's economy. The problem situation is a significant difference between the existing indicators of engine reliability and those possible with optimal parameters of the lubrication system. The aim of the study was to increase the reliability and durability of tractor engines by improving the prevention and tuning of the lubrication system. The paper presents the results of bench and operational studies of the developed oil level controller, as one of the options for tuning tools that provide the optimal oil level in the crankcase of an automotive engine. The intensity of oil aging and the reliability of the engine are largely determined by the frequency of refilling and changing the oil. As a result of the tests, it was found that the developed ROOM provides proportional compensation for the loss of oil from the crankcase. Comparative data on the performance of diesels with and without an oil level regulator are presented. According to the results of operational studies, their results largely confirm the results of experimental studies. A decrease in the intensity of changes in the technical condition of the crankshaft bearings, judging by the oil pressure, occurred by more than 20 %. The decrease in the intensity of changes in the technical condition of the cylinder-piston group, judging by the oil consumption for carbon monoxide, occurred by more than 50 %. The average temperature decreased by 2.5%, which reduced the intensity of aging of the oil and its resource increased by an average of 6.2-16.2 %. Based on the results of the comparison, conclusions are drawn on the effectiveness of this type of tuning of the diesel lubrication system.

Експертна оцінка технічного стану циліндро-поршневої групи двигуна автомобіля

Informative dampers and installation methods do not dose the speed, accurately distinguish the nature of the injustice of the cylinder-piston group and check the tightness of the valves of the single-stage model of the engine, which allows a preliminary quality assessment in the production assessment. . During the inspection, the activity of the "black box" is checked for unknown structural elements, the initial diagnostic obligations that affect. The nomenclature of structural parameters that are checked is determined in accordance with existing standards. Based on the advanced model development method produced by the technical condition of the cylinder-piston group and the sealed valve of the engine, model, detailed dosing, statistical information, machines, machines, machines, machines, machines, machines, machines, machines and equipment. first, to localize the unevenness of the cylinder-piston group and the tightness of the engine valve, and secondly, to formally process the process of automated technical diagnosis; thirdly, it will provide a high rate of indiscriminate diagnosis. To assess the sensitivity of the diagnostic value as a random variable, it is proposed to evaluate not the relative change in the limit and nominal value of the controller, the relative change in the average value of the random variable within the allowable value. The diagnostic parameter is considered stable if the condition under which the absolute maximum value from the average value does not exceed "three sigma" is fulfilled. Informative in consideration is the diagnostic parameter in which the ratio of the difference between the average significant value of the random control in good and faulty state of the object to the difference of standard deviations exceeds one. Expert assessment of the technical condition of the road vehicle is associated with the determination of diagnostic parameters, structural parameters, as well as the reasons that caused the change of these parameters.

Diagnosing the technical condition of the diesel cylinder-piston group

The reliability of locomotive diesel engines largely depends on a timely and objective assessment of the technical condition of its equipment during operation. The article proposes a technique for the integral assessment of the technical state of the quality of the working process in a diesel cylinder using on-board diagnostics.