Internal Combustion Engine Piston Research Articles

FEM Analysis And Design Optimization Of The Piston

The workings of an engine rely on the piston rod and/or connecting rod to transmit the force of the expanding gas in the cylinder to the crankshaft. Because of its critical role in engines, the piston is subject to inertial stresses and cyclic gas pressure, which may lead to fatigue damage in the form of side wear, fractures in the piston head or crown, and other issues. According to the research, the top of the piston experiences the highest level of stress, which is a major contributor to fatigue failure. This study uses finite element analysis to illustrate the stress distribution on an internal combustion engine's piston. It is the CAD and CAE programs that carry out the FEA. Examining and analyzing the distribution of thermal and mechanical stresses on the piston under real-world engine conditions during combustion is the primary focus. Predicting the component's critical area and greater stress using finite element analysis is also detailed in the paper. Created a structural model of a piston using CATIA software. We ran simulations and stress analyses with the help of ANSYS V14.5.

The efficiency of thermal protection of ICE pistons with the micro-arc oxidation

BACKGROUND: In order to protect pistons of internal combustion engines (ICE) from burnout and increase their durability, it is reasonable to use ceramic coatings formed on the piston head with micro-arc oxidation (MAO). Many scientific papers have been devoted to the study of the efficiency of these coatings. However, most of these studies were carried out at laboratory facilities simulating the engine operation, generally, not taking into account the real thermophysical parameters of the MAO coating. Therefore, the thermal protection efficiency of these coatings is difficult to assess. AIM: Study of efficiency of the thermal protection of pistons using a ceramic coating formed by micro-arc oxidation on the piston head with numerical simulation. METHODS: The study was conducted in the SolidWorks Simulation software. Two piston aluminum alloys were used as the piston material: AK12d (with a silicon content of 12%) and AK4-1 (with a silicon content of 0.35%). Temperature loads corresponding to the operation of a real engine were applied to the surfaces of the model piston. At the first stage of the study, the thermal state of pistons made of different uncoated alloys was simulated. At the second and third stages of the study, the effect of the coating thickness on the piston thermal state was simulated. The piston material of the second study stage was the AK4-1 alloy. The piston material of the third study stage was the AK12d alloy. Ceramics, which properties correspond to the coatings properties formed with the micro-arc oxidation method on these alloys, were used as the coating material. The coating thickness varied in the range from 50 to 350 µm in increments of 100 µm. The probing method was used to determine the temperature in various areas of the piston, such as at the piston head surface at the MAO coating and under it, in the area of piston grooves, at a piston skirt and the piston head from the side of a crankcase. RESULTS: With the simulation, it was found that: The micro-arc coating of the piston head reduces the thermal tension of the piston regardless of the aluminum alloy chemical composition. The efficiency of the piston’s thermal protection increases with an increase in the ceramic coating thickness and a decrease in its thermal conductivity coefficient. The greatest heat-protecting effect is achieved by the piston made of the AK12d eutectic alloy. CONCLUSIONS: It is found that the MAO coating at the piston head is an effective way to reduce the thermal tension of the ICE pistons. Increasing the ceramic coating thickness and a decrease in its thermal conductivity coefficient increases the efficiency of the pistons thermal protection. Reducing the thermal conductivity of the MAO coating and increasing the MAO coating thickness increases the temperature on the coating surface.

Improving the physical, mechanical and operational characteristics of cast internal combustion engine pistons made of aluminum alloy using secondary charge

The article is devoted to improving the physical, mechanical and operational characteristics of cast internal combustion engine pistons made of aluminum alloy using secondary charge. The advantage of the proposed approach is that these parts are manufactured from any aluminum alloy using the remelting of failed internal combustion engine parts of the same name. The paper shows that while using a secondary charge in the form of remelting failed parts of the same name, the quality of cast products not only does not deteriorate, but, on the contrary, their physical and mechanical characteristics even increase. It should be noted that the high density of the alloy obtained from remelting failed pistons and the high degree of its modification confirmed the authors’ assumption that in this case refining and modification operations can be avoided. The presented approach using the remelting of failed parts makes it possible not only to save fresh charge materials, but also to preserve the chemical composition of the primary parts, and, consequently, the level of their physical, mechanical and operational characteristics.

Analysis of scooter engine piston damage

The causes of operational damage to the piston of a single-cylinder two-stroke internal combustion engine (ICE) of a scooter, made of a piston aluminum-silicon alloy by mold casting, were investigated. It was found that the AK21M2.5H2.5 type alloy has a dispersed eutectic structure (α+β-Si) with a small number of primary silicon crystals of a compact shape, the size of which does not exceed 10 μm. The porosity of the cast alloy of the piston is less than the lowest 1st porosity point, as well as the quality structure, could not be the cause of its damage. The average value of the microhardness measured on the surface of the piston head (70 HV0.98) is slightly less than the standardized hardness (90 НВ ÷ 100 НВ) of ingots after mold casting and artificial aging without preliminary hardening, which indirectly indicates overheating of the piston during operation. The detected damage to the outer surface of the piston in the form of deep scratches and worn stripes is not caused by metallurgical or technological factors, but by violations of operating conditions: overheating and lack of lubricant in the contact zone of the piston and cylinder.

Analysis of the effectiveness of using torsional vibration dampers for crankshafts with adaptive characteristics in internal combustion engines

The research aims to determine the effectiveness of torsional dampers with adaptive characteristics for crankshafts of piston internal combustion engines. The paper deals with the pressing issue of designing a torsional vibration damper for crankshafts of internal combustion engines, which can work efficiently in the entire operating range of speed variance. The standard approach to design the damper with constant characteristics implies one resonant operating mode, which in actual practice is not always justified. This fact decreases the operating efficiency, especially for the forced V-type engines. In order to determine the design parameters of dampers with adaptive characteristics, a multi-parameter optimization problem must be solved, which requires experimental validation. The work considers an approximate method, according to which the main parameters of the designed damper for different operating modes are determined. We obtained the general trend of changing the torsional damper characteristics by performing calculations for different engine operating modes. Based on these data, it is possible to determine the operating modes of the control mechanism. Comparing the efficiency of dampers with constant characteristics under the same modes allows validating the results’ adequacy. The scientific novelty lies in the developed method of modes determining torsional vibration damper parameters at changing speed and operating can help design new efficient forced internal combustion engines.

Effect of mao ceramic coating on the stress-strain state of internal combustion engine pistons

Effect of mao ceramic coating on the stress-strain state of internal combustion engine pistons

The concept of the contact angle in the process of oil film formation in internal combustion piston engines

In internal combustion piston engines, the process of oil film formation differs from that in industrial machines. The adhesive strength of the molecules at the interface between the coating of engine parts and the lubricating oil affects the load carrying capacity and the ability to form a lubricated film. The geometry of the lubricating wedge between the surfaces of the piston rings and the cylinder wall is determined by the thickness of the oil film and the amount of oil coverage of the ring. This state is modified by many parameters describing the operation of the engine and the physical and chemical parameters of the coatings of the cooperating pairs. For lubricating molecules reaching energies greater than the energy barrier of adhesion at the boundary, sliding occurs. Therefore, the value of the contact angle of the liquid on the surface of the coating depends on the value of the intermolecular force of attraction. According to the author, there is a strong correlation between the contact angle and the lubrication effect. Research indicates that the potential barrier is a function of the contact angle and the contact angle hysteresis (CAH). The innovation of the work consists in the study of the contact angle and CAH in the conditions of thin layers of lubricating oil in cooperation with hydrophilic and hydrophobic coatings. The thickness of the lubricating film was measured under various speed and load conditions using optical interferometry. The study proves that CAH is a better interface parameter to correlate with the effect of hydrodynamic lubrication.

Analysis of the prospects for hydrogen-fuelled internal combustion engines

Hydrogen, as a zero-emission fuel, makes it possible to build a piston combustion engine that can be qualified as a drive for a "Zero Emission Vehicles", in terms of CO2 emissions. Thus, a hydrogen-powered piston combustion engine may be a future transitional technology for powertrains, especially in trucks and off-road vehicles, competitive with both electric drives and fuel cells. The article presents a multi-directional analysis of the prospects for the development and dissemination of hydrogen-powered internal combustion piston engines in motor vehicles. The current interest of the automotive industry in hydrogen-powered internal combustion engines, current state of their development and the challenges that need to be overcome were presented. Various conditions that will determine their future in Europe were also indicated.

An Overview of the Global Market, Fleet, and Components in the Field of Aviation Gasoline

Aviation gasoline is a fuel for spark-ignition piston internal combustion engines, which are usually used in light aircraft (small aviation and general aviation). This technique is widely used for regional and interregional transportation, for the initial training and retraining of aviation staff, for private use, for agricultural purposes, for the development of aviation sports and tourism, and for combat and rescue operations. This article gives some estimates of the production and consumption of aviation gasoline in the EU, North and South America, Asia–Pacific, Africa, and CIS countries. Export possibilities and the reliance on import within different regions are analyzed. Economic indicators for aviation gasoline are calculated by assessing the share of its production in the GDP and per capita consumption. In the context of the transition to unleaded aviation gasoline, the structure of the piston aviation fleet and its readiness for the transition are considered. The paper also analyzes the following existing components of unleaded aviation gasoline: technical capabilities and promising components.

PROFILING OF THE OUTER SURFACE OF THE PISTON

The piston is one of the main resource-intensive and knowledge-intensive parts of the internal combustion engine. Its design significantly affects almost all indicators of the perfection of the power plant with internal combustion engines as a whole. A correctly designed profile is the main parameter that allows the engine to blow safely during the first starts. The development, production and use of pistons in the primary and secondary markets is impossible without appropriate scientific research that will increase the design and technological capabilities of all interested parties. Pistons for gasoline internal combustion engines of passenger cars will continue to dominate the markets, which is connected with the greening of transport as a whole. This emphasizes the importance of research on the improvement of positive-ignition internal combustion engine pistons. Rational profiling of the outer surface is an important task for improving the design of the piston. The diagram of the design creation technology, which was adopted by JSC "AVTRAMAT" (Kharkiv Plant "Porshen") as the standard of the enterprise, according to which pistons were created, which were then supplied to factories of the engine-building industry and for spare parts, is given. The profiles of the side surfaces of the pistons of automobile internal combustion engines, which were designed and implemented in production, were analyzed. The analysis was carried out for pistons with a diameter of 72 to 100 mm and a height of 45 to 73 mm. It is shown that the given profiles of the side surfaces in these pistons are geometrically similar both along and perpendicular to its axis. It is shown that the geometric shape of the profile can be described by polynomials of the 3rd and 4th degree, which allows for easy further use. This can be used when designing the profiles of future structures. Formulas and an algorithm are given, according to which it is possible to calculate the external profile of pistons of automobile reciprocating internal combustion engines according to 2 parameters - diameter and height.

The use of high-strength cast iron with a ferritic structure for the reciprocating displacement system of the internal combustion engine pistons and the improvement of its operation parameters

A study of compositions of samples of high‑strength cast iron, the use of which is possible in the development of an internal combustion engine with an improved design of a combined reciprocating conversion system, has been carried out. A number of research methods were carried out, including isothermal hardening. The optimal combination of strength and plastic properties have samples from high‑strength cast iron containing, wt.%: 2.9–3.1 C; 3.2–3.5 Si; 0.28–0.31 Mn; 0.7 Cu; 0.35 % Mo and 0.025B. Also, in the course of the study, the possibility was considered and studies were conducted on quenching cast iron in a spray chamber and jet cooling, as an alternative to traditional quenching in molten salts. The data obtained indicate that during jet‑air isothermal quenching, the structure of cast iron is completely and uniformly formed along the cross‑section, while providing a level of tensile strength up to 950 MPa, hardness up to 360–370 NV while maintaining elongation at tension up to 8 %. The use of such a class of cast iron in improved KSPVPP will both increase the life of the internal combustion engine as a whole, and improve its operational characteristics – reduce noise and reduce the weight of the structure.

Thermodynamic analysis and comprehensive system optimization of the near zero emission hybrid power based on SOFC-ICE integrated system fueled with ammonia

The highly efficient heat and mass integrations fueled with ammonia of solid oxide fuel cell and reciprocating piston internal combustion engine are conducted from the viewpoints of characters of restrained / unrestrained chemical reaction and principle of energy cascade utilization. According to previous studies, we classified such integrations into serial and parallel topologies. Based on the detailed and verified models, the power matching limits of serial and parallel integrations are proposed first, showing a narrow scale of power matching of fuel cell and engines, due to the finite engine displacement. Furthermore, based on the design concepts of serial and parallel integrations, the improvement and optimization of combined systems were conducted, which showed that the possibly highest efficiency of serial and parallel systems can reach 70.53% and 68.40%, respectively. Additionally, the exergy analysis of systems could prove that such heat and mass integrations can effectively use remaining heats and fuels, leading to less exergy destructions and optimal designs and operation points achievement, while the maximum exergy destruction occurs at engine. Finally, the environmental analysis results showed that the corrected NO, NO2, N2O and NH3 emissions can reach 0.01 mg/kWh, 5.00 μg/kWh, 29.50 mg/kWh and <5 ppm, achieving near zero emissions.

The Theory of the Surface Wettability Angle in the Formation of an Oil Film in Internal Combustion Piston Engines.

In internal combustion piston engines, the formation of an oil film is completely different from that seen in industrial machines. The molecular adhesion force at the interface between the surface coating of engine parts and the lubricating oil determines the load-carrying capacity and the ability to form a lubricated film. The geometry of the lubricating wedge between the surfaces of the piston rings and the cylinder wall is created by the thickness of the oil film and the height of the ring's coverage with lubricating oil. This condition is affected by many of the parameters that characterize the engine's operation and the physical and chemical parameters of the coatings used for the cooperating pairs. For lubricant particles that reach energies that are higher than the potential energy barrier regarding adhesive attraction at the interface, slippage occurs. Therefore, the value of the contact angle of the liquid on the surface of the coating depends on the value of the intermolecular force of attraction. According to the current author, there is a strong relationship between the contact angle and the lubrication effect. The paper shows that the surface potential energy barrier is a function of the contact angle and contact angle hysteresis (CAH). The innovation of the current work consists in examining the contact angle and CAH under the conditions of thin layers of lubricating oil, in cooperation with hydrophilic and hydrophobic coatings. The thickness of the lubricant film was measured under various speed and load conditions, using optical interferometry. The study shows that CAH is a better interfacial parameter for correlation with the effect of hydrodynamic lubrication. This paper presents the mathematical relationships relating to a piston engine, various coatings, and lubricants.

Three-dimensional CFD-solid mechanics analysis of the hydrogen internal combustion engine piston subjected to thermomechanical loads

Fueling internal combustion engines with hydrogen is one of the most recommended alternative fuels today in order to combat the energy crisis, pollution problems, and climate change. Despite all the advantages of hydrogen fuel, it produces a higher combustion temperature than gasoline. In an internal combustion engine, the piston is among the numerous complex and highly loaded components. Piston surfaces are directly affected by combustion flames, making them critical components of engines. To examine the stress distribution and specify the critical fracture zones in the piston for hydrogen fuel engines, a three-dimensional CFD-solid-mechanics model of the internal combustion engine piston subjected to real thermomechanical loads was analyzed numerically to investigate the distribution of the temperature on the piston body, the interrelated thermomechanical deformations map, and the pattern of the stresses when fueling the engine with hydrogen fuel. With the aid of multiphysics COMSOL software, the CFD-solid-mechanics equations were solved with high accuracy. Despite the increase in pressure on the piston and its temperature when the engine is running on hydrogen fuel, the results show that the hydrogen fuel engine piston can withstand, safely, the thermomechanical loads. In comparison to gasoline fuel, hydrogen fuel caused a deformation of 0.34 mm, an increase of 17%. This deformation is within safe limits, with an average clearance of 0.867 mm between the cylinder liner and piston.

A review on preparation process and tribological performance of coatings for internal combustion engine piston ring

Reducing the energy consumption and exhaust emission, and improving the combustion efficiency of internal combustion engine are important for solving the problems of climate change and environmental pollution. The piston ring-liner system is one of the most serious friction pairs in internal combustion engine, accounting for 26% of the total friction loss. Depositing strengthened coatings on the surface of piston rings is an effective method to reduce the friction coefficient and wear rate. This paper reviews the research progress of several representative technologies for preparing coatings, such as electroplating, physical vapor deposition (PVD), thermal spraying and chemical vapor deposition (CVD), and so on. Various coatings, such as Cr-Al2O3 coating prepared by representative electroplating process, CrN and DLC coatings prepared by physical vapor deposition, and Mo-based and C-based coatings prepared by thermal spraying process, are briefly discussed. Furthermore, the positive and negative aspects of commonly used piston ring coatings are compared, and their development trends are summarized.

Estimation of the degree of internal recirculation in Internal Combustion Engines

The concepts of residual gas and admission (or volumetric efficiency) coefficients are used exclusively by specialists in the field of piston Internal Combustion Engines. However, it is preferable to apply the concepts of volume fractions of components of the working mixture consisting of air, fuel, residual, and recirculating gases, for the evaluation of filling. This simplifies and makes it more easy-to-grasp the influence of individual factors on the results of gas exchange processes. The proposed approach makes it possible to take into account the impact on the engine indicators of the molecular weight of the fuel used and the degree of external recirculation, as well as to reduce the number of independent variables. At the same time, the displacement coefficient A proposed by the author characterizes a decrease in filling when an engine with external mixing is switched to a gaseous fuel with a lower molecular weight. A change in the valve timing made it possible to produce an effect on the composition of the working mixture and, thereby, the environmental characteristics of the engine. In the case of external recirculation, it becomes necessary to estimate the summary fraction of neutral combustion products in the working mixture, on which all engine operation depended. This "overall degree of recirculation" can also be determined using the proposed approach.

Coatings protecting against aviation piston engine seizure

The article presents the basics of manufacturing porous (16%) composite coatings based on phenolic resin reinforced with glassy carbon particles (30 wt%). These coatings, when applied to a steel push rod surface, prepared by sandblasting, of the timing system of an aircraft piston internal combustion engine, prevent seizure of the contact in conditions of lubrication failure up to 10 h (μ≈0.1 by p = 8 MPa, v = 0.5 m/s), extending the last stage of flight time of the aircraft. The reference coating undergone seizure, μ> 1 after 5 h. The conditions and results of laboratory tests on a pin-on-disc tribological tester and tests on an engine test bench are described. The dependencies of the coefficient of friction and wear of the push rod on the glassy carbon content, thinner viscosity and sandblasting pressure, described by the equations of the second degree, allowed the optimal conditions to be determined to the produce coatings. The test results of the developed composite porous coatings were compared with the results of non-porous commercial coatings. The wear of developed coating compared to reference one and matrix coatings was respectively ΔmCC = −1.63 mg (mass increase), ΔmRC = 1.3 mg and ΔmMC = 5.56 mg.

The Theory of the Surface Wettability Angle in the Formation of an Oil Film in Internal Combustion Piston Engines

The Theory of the Surface Wettability Angle in the Formation of an Oil Film in Internal Combustion Piston Engines

Analysis of the Welding Process of Steel Pistons of Internal Combustion Engines

The aim of the article is to analyze the friction welding process of steel pistons, due to the small amount of scientific literature on this subject. First, it is necessary to present the design fea-tures of steel pistons and their advantages and disadvantages. Then analyze the types of friction weld-ing processes used in the production of pistons of internal combustion engines with the analysis of their differences. Present two basic methods of welding in the production of steel pistons, i.e. friction butt welding and low pressure friction welding. Finally, a proper analysis of the friction welding pro-cesses of steel pistons of internal combustion engines can be presented. At the end, the conclusions of the analysis are presented and proposals for improving the process are made.

Method and a Device for Testing the Friction Force in Precision Pairs of Injection Apparatus of the Self-Ignition Engines

This article reviews the state of the knowledge and technology in the field of friction-loss measurements in internal combustion piston engines. The dependencies that describe the loss of energy in combustion engines and injection apparatus are presented. Currently, very little can be found in the literature on the study of frictional forces in injection apparatus, but mainly in the piston–cylinder group, so this work significantly fills that gap. The aim of this article is to construct a device and to develop a method for assessing the technical state of injector nozzles to minimize friction losses in internal combustion engines at the stages of evaluation, design, production and operation. This article presents a stand for determining the maximum friction forces due to gravity loading by water-jet control. This article also presents test results on the maximum friction force between a needle and a body of injector nozzles in piston combustion engines on a designed and purpose-built stand outside of the combustion engine. Various designs and injector nozzles are made from various types of alloy steel for marine and automotive piston internal combustion engines fueled with distillation or residual fuels, and are tested. The research concerned conventional elements for the injection apparatus as well as electronically controlled subsystems. Precision pairs of injection equipment are selected for the tests: new ones are employed after the storage period and operated in natural conditions. The elements dismantled from the internal combustion engines are tested in the presence of fuel or calibration oil of similar properties. The maximum static frictional forces under the hydrostatic loading are measured, alongside the parameters for the dynamic movement of the nozzle needles from bodies of the injector nozzle as time, speed, acceleration and dynamic force. The influence of the angular position of the needle in relation to the bodies of the precision pairs conventional internal combustion engines, the diametral clearance between the nozzle body and needle, and the surface conditions on the values of the maximum friction force are also presented. Errors in shape and position result in the uniqueness of the friction force at the mutual angular position of the needle in relation to the nozzle body, and the decrease in diametral clearance and deterioration of the surface state increase the friction losses. A model was elaborated of the influence of various factors on the value of the maximum friction force.