Production Of Pistons Research Articles

Fatigue and Fracture Behaviors of Short Carbon Fiber Reinforced Squeeze Cast AZ91 at 20 °C and 250 °C

AZ91 is one of the most broadly used Mg alloys because of its good castability and reasonable mechanical properties. Strengthening AZ91 with carbon short fibers aims to increase tensile and fatigue strength, creep, and wear resistance. One of the proposed applications of reinforced AZ91 is the production of pistons for trucks. Such reciprocating parts are subjected to alternating fatigue loads which can lead to fatigue failure. In this respect, studying the tensile and fatigue behavior of materials subjected to such loading conditions is of great interest. The alternating low-cycle fatigue (LCF) and high-cycle fatigue (HCF) of unreinforced AZ91 and carbon fiber-reinforced AZ91 (AZ91-C) were investigated at 20 °C and 250 °C. Tensile tests were carried out at the same testing temperature to find the appropriate fatigue testing stress and strain for stress-controlled and strain-controlled tests, respectively. The fatigue curves of stress against the number of cycles (S–N) revealed that the composite AZ91-C’s fatigue strength was 55 MPa under HCF, while that of the matrix alloy AZ91 was only 37 MPa at 250 °C. Fracture investigations were conducted on the broken test samples. The fracture approach in the matrix material (AZ91) is mixed ductile/brittle containing fatigue serration, fiber fracture, and separation in the reinforced material (AZ91-C).

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.

Multi-response optimization and machinability research of forging and heat treatment parameters in piston production

Multi-response optimization and machinability research of forging and heat treatment parameters in piston production

Investigation on impact and wear behavior of Al6061 (SiC + Al2O3) and Al7075 (SiC + Al2O3) hybrid composites

The current study focuses on the properties of dry sliding characteristics and impact strength of two different aluminum alloys that were reinforced with 100 nm sized Silicon carbide (SiC) and Aluminum oxide (Al2O3) ceramic particles, for improving the mechanical properties of the final alloy with the mixing materials characteristics. Stir casting method is adopted for fabricating the composites, matrix being Al6061 and Al7075, utilizing three distinct reinforcement ratios. In order to improve the mechanical properties and increase resistance to wear, tear, and shear, SiC and Al2O3 are utilized as reinforcing elements. Following the creation of the composite matrices, their physical and mechanical behaviors are examined in accordance with ASTM standards, and a comparison between the hybrid composites made of Al6061 and Al7075 is then completed. Comparison of the obtained samples showed that the Al7075 (12 % SiC + 6 % Al2O3) alloy exhibits characteristics with exceptional tribological and mechanical characteristics. The studied alloy can be used in the automotive industry, for example, in the production of pistons, connecting rods, due to the minimum degree of wear and variable thermal expansion coefficient.

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.

Production process automation of internal combustion engine (ICE) pistons from hypereutectic silumins by injection molding with crystallization under pressure, followed by isothermal forging

A technology for the production of ICE pistons from aluminum alloys with a silicon content of 18 % is proposed. A method for pressing a crystallizing metal by pressure on a horizontal hydraulic press in order to obtain piston blanks for subsequent isothermal forging is developed. The pressing process is controlled by a computer control system embodied through the use of the modern industrial logic controllers and software. An interface for program control is developed. It indicated that the use of modern process control systems makes it possible to control the formation of the final product properties in real time. Keywords automation, computer control system, internal combustion engine pistons, isothermal forging, crystallization, pressure, mechanical properties of metal products

An experimental study based on Six Sigma approach to optimize chip formation in machining

Quality and productivity have been distinguished as a significant role in any organization, especially for the manufacturing industry to gain more profit that prompts achievement of a company. In the manufacturing of pistons, the makers who are competing in the market want their products to be manufactured at less expense. In a large-scale manufacturing organization, which intends to produce around 600 to 800 parts per shift per line each and every single rejection record to the deficiency of Productivity. Defectives are investigated again and rework has to be done to bring down the number of damaged pistons, hence it reduces the quality of the product manufactured, devouring additional man and time. This paper reports a work improvement project in Federal-Mogul Goetze India limited. It involves Problem Identification in the production of pistons and proposing an effective framework to improve the current situation effectively. Based on the observation and data collection on day-to-day productivity, the major problem has been identified. To study and improve the problems identified methodology adopted is Six Sigma. DMAIC helps in understanding the process and the variables that affect it so that can be optimized the processes. The main objective of this case study is to reduce the number of defective pistons produced in the Piston Machine Shop. The outcome of this study is a suggestion to improve the process efficiency by parameter optimization that identifies and determines the root cause and controls the factors leading to desired output by following six sigma approaches.

Application of MDO technology for internal combustion engines

The prospects of using nano-crystalline ceramic coatings on internal combustion engine parts obtained by micro-arc oxidation (MDO) technology are considered. The tendency of development of engine building on replacement of cast-iron blocks and sleeves on aluminum with the special coverings received by galvanic methods is shown. It is noted that this direction does not involve the use of repair technologies, which significantly affects consumers. Analysis and practical tests have shown the possibility of using MDO technology both in the manufacture of engine parts and for the performance of restoration work. It is concluded that it is necessary to introduce this technology into the mass production of engines and pistons, as well as the need to develop a set of equipment for repair work.

Investigation of the pressure and heat treatment effect on the ICE piston blanks mechanical and structural properties from high-strength aluminum alloy B95

The features of the production of internal combustion engine pistons are analysed. On the basis of the analysis, the expediency of developing a new, more improved technology for the production of piston blanks was revealed. The choice was made in favour of the injection molding process. It is shown that the high quality of workpieces with minimal material and energy costs can be ensured by imposing high pressure on the metal prior to crystallization. The scientific and technical literature is analysed, where attention is drawn to the relevance of the processes of processing crystallizing metal by pressure using hydraulic press equipment. However, it can be seen from the available sources that the possibility of pressure treatment of liquid metal prior to the onset of crystallization remains unexplored. Investigations of the mechanical properties of the resulting blanks of internal combustion engine pistons have been carried out, and the microstructures of the alloy obtained under different crimping modes have been studied. As a result of the research, the most optimal technological modes of pressure application were determined. The process of applying pressure to the crystallizing metal has been developed.

Box-Behnken Design Optimization of Sand Casting Process Parameters

Sand casting is reputed for the manufacture of engine components as a result of its ease of operation. An assemblage of process parameters at optimal conditions leads to enhanced mechanical properties of automobile engine components. The Response Surface Methodology Design of experiment created an experimental layout for the sand casting process parameters and the various levels as applied in the production of engine pistons at the foundry. The Box-Behnken Design provided a matrix of 27 experiments to be conducted. Multiple linear Regression technique was employed to develop a mathematical model for the hardness of the aluminium alloy. The developed model was inputted into the evolutionary Genetic Algorithm tool box as an objective model. The optimal levels determined from the Genetic algorithm were used to carry out actual experiment in the foundry and the result was similar to the predicted hardness value of the developed model. Statistical ANOVA test conducted showed that the mathematical model was adequate with a R2 value of 81.02% and R2 (adjusted) value of 60.07%. The developed model has a p-value of 0.016 which indicates that the model was significant. The optimal values obtained for pouring temperature, vibration frequency, vibration time and runner size are 700oC, 31.52Hz, 59.998sec and 469.69mm2 respectively.

A novel approach applied to fault diagnosis for micro-defects on piston throat

The identification of different types of micro-defects on piston throat is of great significance to improve the efficiency of piston production and the safe operation of the engine. The two challenges to the micro-defects classification are to reduce the impact of imbalanced labeled samples on training, and to spend less cost of experts for labeling. To overcome these challenges, SMOTE and a new selecting strategy applied to the active learning on SVM algorithm (E-SVM-AL) is proposed. The strategy includes two portions: (1) a method for preprocessing unlabeled samples, which can be combined with uncertainty-based sampling criterion to improve labeling efficiency; and (2) a model to determine the number of labeling samples with experts, which is based on the current hyperplane, and can obtain an additional stopping criterion. Experiments using the system based on E-SVM-AL algorithm show the efficiency and accuracy in the classification of micro-defects on different batches of pistons.

Peculiarities of choice of materials for pistons of heat engines

In the modern automotive industry, heat engine pistons must have sufficient strength characteristics to ensure the necessary reliability and durability under high dynamic, mechanical and thermal loads. Currently, aluminum alloys, cast iron, steel and composite materials are used in domestic and international practice for the production of pistons. The use of cheap reinforcing elements made of carbon materials instead of expensive ceramic and boron fibers, silicon carbide particles will significantly reduce the cost of pistons and make them more affordable for mass production.

ПЕРСПЕКТИВЫ ИСПОЛЬЗОВАНИЯ ТЕХНОЛОГИИ МДО ДЛЯ ДВИГАТЕЛЕЙ ВНУТРЕННЕГО СГОРАНИЯ

microarc oxidation (MAO) technology. The authors reveal an engine development tendency to replace cast-iron blocks and liners with aluminum ones with special coatings obtained by electroplating methods. It is noted that this method does not involve the use of repair technologies, which signifi cantly aff ects consumer costs. The paper shows the prospects of using MAO technology both in the manufacturing of engine parts and restoration operations. To assess the eff ectiveness of the proposed technology, practical study was performed on covering the working part of the cylinder used in small-size agricultural machinery. The engines were tested at 5.1 kW at 3,600 rpm for 300 hours. After testing, no defects or wear were found on the cylinder face. Preliminary test results of the assembled engine showed no loss of power over 10,000 hours of car mileage, which indicates that the geometric parameters of the parts are preserved. The authors emphasize that the most optimal combination is the friction pair of two parts with an MAO coating. It has been established that the introduction of nano-additives in a MAO-coating leads to a decrease in the coeffi cient of friction between the cylinder and the piston ring and reduces the wear of piston rings and the cylinder face in more than 10 times. A conclusion is made about the feasibility of introducing the considered technology into the mass production of engines and pistons, as well as developing a set of repair equipment.

An experimental study of the stress-strain state of the engine piston skirt on the engineless stand

The article describes the features developed by the authors of the profiling method of the piston skirt, provides the main parameters that affect the lubrication conditions of the piston skirt and the magnitude of mechanical losses. In computational studies, the basic formulas are given for determining the thickness of the oil layer in a piston skirt - cylinder sleeve conjunction to assess the nature of friction. To determine the deformations, the finite element method is used on the spatial model of the piston. To verify the finite element model, a stand for experimental studies was developed. The article describes the developed stand, the methodology and results of experimental studies of the stress-strain state of the two-piece piston skirt obtained at this stand and a comparative analysis of the results of the calculated and experimental studies of the stress-strain state of the two-piece piston skirt of a diesel engine. The research results showed that the developed stand can be used to verify mathematical models for calculating the stress-strain state of the piston skirt in the pilot production of internal combustion engine pistons to accelerate and reduce the cost of the piston design development process, as well as the results of experimental studies obtained at the stand, can be used as initial data for the developed mathematical model of the dynamics of the movement of the piston and the profiling of the piston skirt.

Surface modification of A390 alloy with CaB6 composite coating

A390 alloy is widely used in piston production and owing to the adverse work conditions of piston, the demand for performance, especially surface performance of A390 alloy is very high. Grain refinement and Sr modification are widely used to improve the performance of A390 alloy, but this melt treatment for the improvement of surface properties is limited. In our study, in order to achieve excellent surface performance, a hard protective CaB6 composite coating was built on the surface of A390 alloy by laser cladding. Results show that the in situ synthesized CaB6/A390 composite coating exhibits ideal combination of good adhesion, high hardness and high abrasive resistance. Both of the surface and internal microstructure of A390 alloy can be modified and its performance can be improved remarkably owing to the formation of CaB6 composite coating. The brinell hardness of the coating can reach 136.2 HB, increased by 24.7 % and the abrasive resistance of A390 alloy can be improved by 17.7 %.

Aluminum Matrix Composite (AlSi7Mg2Sr0.03/SiCp) Pistons Obtained by Mechanical Mixing Method.

Metal matrix composites are undoubtedly a group of advanced engineering materials. Compared to unreinforced matrix material, they are characterized by increased strength, greater stiffness, increased wear resistance, better mechanical properties and dimensional stability at elevated temperatures as well as lower density. Due to its very favorable tribological properties for many years research has been conducted on the application of MMC in friction node. The article presents important technological aspects related to the production and properties of composite pistons. Under industrial conditions, a composite suspension (AlSi7Mg2Sr0.03/SiCp 10 vol %) was prepared to allow casting of the semi-finished pistons series. Machining parameters of the working surfaces of the piston were selected on the basis of the turning test made on PCD, PCNM and uncoated carbide tools. The tribological properties of the composite pistons were determined on the basis of the pin-on-disc and the abrasion wear. The scuffing tests carried out under real operating conditions have confirmed the possibility of using composite pistons in air compressors.

Development of a system for organizing a modular design and technological preparation for the production of cast iron pistons for internal combustion engines

Modern engine building requires a significant increase in power, fuel efficiency and ensuring high environmental performance of internal combustion engines (ICE). When forcing the operating modes of diesel engines, one of the most loaded engine parts becomes a piston, due to a significant increase in mechanical and thermal stresses. With increasing load on the piston, the difficulty of meeting the high demands for them increases. When creating modern ICE and improving the quality of existing ones, special attention is paid to the design and technological preparation of the production of pistons, which is the object of research. Pistons determine the reliability and life of the engine as a whole.To solve this problem, all the main works related to the design and manufacture of cast-iron pistons are proposed to divide into separate modules, performed simultaneously in three areas: organizational, design and technological. These modules are integral sectors of a single modular system for organizing design and technological preparation for production of cast iron pistons. Modeling of the stressed-strain state of monolithic cast-iron pistons is considered for an example of implementation of one of the modules. The results of calculations of the stress-strain state and the temperature distribution field in the body of the piston are presented. The results show that the maximum temperature is 315 °C and concentrated on the edge of the combustion chamber. The stress does not exceed 617 MPa.

The role of elevated temperature exposure on structural evolution and fatigue strength of eutectic AlSi12 alloys

Pistons of internal combustion (IC) engines are typically subjected during operation to high cycle fatigue loading at elevated temperatures (up to 350°C). The materials typically used for piston production are eutectic Al–Si alloys for their excellent fluidity and suitable mechanical properties. Results of a fatigue testing program of eutectic Al–Si alloys at room temperature and at elevated temperatures (250°C, 300°C and 350°C) performed with the aim to support piston design and material optimization are reported in this paper. Specimens were extracted from piston crowns and tested in a rotating bending test machine. The fatigue strength at 107cycles was quantified by a staircase approach.To investigate the strengthening mechanism based on the formation of precipitates (Guinier–Preston (GP) zones) during decomposition of a metastable supersaturated solid solution, a structural investigation of one of the alloys before and after fatigue testing at elevated temperatures was conducted. Metallography, color etching, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to elucidate the following aspects: (1) the structural features of the alloy (dendrites of α-phase, primary Si particle size and distribution, morphology and distribution of intermetallic phases); (2) the changes of the strengthening mechanism (GP zones) with elevated temperature exposure.

Study on Multi-Objective Optimization of Hybrid Flow Shop Scheduling Problem

Due to several mutual conflicting optimized objectives in the hybrid flow shop scheduling problem, its optimized model, including three objectives of make-span, flow-time and tardiness, was firstly set up, instead of the single optimized objective. Furthermore, in order to improve the optimized efficiency and parallelism, after comparing the normal multi-objective optimized methods, an improved NSGA-II algorithm with external archive strategy was proposed. Finally, taking a piston production line as example, its performance was tested. The result showed that the multi-objective optimization of hybrid flow shop scheduling based on improved NSGA-II provided managers with a set of feasible solutions for selection in accordance to their own preference. Therefore the decision could be made more scientific and efficient, and thus brings to the factory more economic benefits.

Reliability Defects Identification of Serial Production Systems: Application to a Piston Production Line

Failure and repair data are urgently needed for reliability and maintainability analysis of production lines. A piston production line is traced, and field failure data during a period of 15 months are collected. The statistical analysis of the failure and repair data and the determination of the theoretical distributions parameters that best fit to failure data were carried out, based on which, reliability of the piston production line is evaluated from a global perspective. Furthermore, a failure losses-based importance measure method for repairable systems was proposed and used for reliability defects identification of the piston production line from a local perspective, the primary failure modes and equipments that were prone to failures were ranked with this method. This analysis will be essential and valuable to identify the reliability problems for current and further designing projects of production lines for piston or other important parts of motor engine.