Aluminum Piston Research Articles

Effect of Different Reinforced Metal-Matrix Composites on Mechanical and Fracture Behaviour of Aluminium Piston Alloy

Al-Si10Cu2Fe and Al-Si12Cu aluminium alloy composites were fabricated by using various weight percentage of SiC and TiB2 reinforcement particles in a two-step stir-casting process to improve their corrosion resistance for use in transport, aerospace and marine industries. Morphological and microstructural analysis of the composites were carried out using field-emission scanning electron microscopy and energy dispersive X-ray spectrometry, respectively. The results indicated a homogeneous distribution of the SiC and TiB2 particles in the matrix, resulting in enhanced materials with better mechanical properties. The improvement of the tensile strength and elastic modulus for Al-Si12Cu–7%TiB2 was 73% and 15.3%, respectively, as compared with the Al-Si10Cu2Fe matrix alloy. The uniform incorporation of SiC and TiB2 microparticles increases the bonding strength with the matrix and improves the hardness. These properties are useful to improve the tribological behaviour.

A study on thermomechanical properties of zirconium di oxide coated piston material of various thickness and its comparison with uncoated material

The working temperature of IC engine is around 2400 °C, and the melting point temperature of aluminium piston is 640 °C in order to avoid the catastrophic damage to IC engine parts all the engine parts is either air cooled or water cooled to the working temperature of IC engine parts, results in decrease in the efficiency of IC engine since some amount of heat energy is carried by cooling fluid. In the present work zirconium, di oxide is used as coating material since of its higher melting point temperature which is 2715 °C. the aluminum piston is cut into 1 in. by 1 in. specimen of three numbers each specimen is coated by 0.25 mm and 0.35 mm zirconium di oxide by using plasma spray process, microstructure of the coated specimens are studied using SEM it is found that with increase in coating thickness the porosity of the specimen is decreasing, hardness test is conducted by using Brinell hardness testing machine it is concluded that the hardness of the coated samples is increasing with increasing the thickness of coatings, and it is more than the un coated specimen, corrosion test is carried by using vanadium Penta oxide and sodium sulphate as salt, experimental results shows that coated specimen is not undergoing any chemical changes in the presence of the salt, The thermal stability is conducted using muffle furnace it is observed that the uncoated material has melted around 650 °C, whereas the coated specimen was successfully resisted the heat energy up to 1400 °C without any physical deformation.

Фрактографічний аналіз іонноазотованих зразків з алюмінієвих поршнів двигунів сільськогосподарської техніки

For a more detailed study of kinetics and the mechanism of destruction, the influence of the environment and the load on the resistance of the samples with heat-protecting diffusion ion-accounted layers, a number of additional fractographic studies should be carried out. The presence of this information will increase the strength and reliability of both coatings and coatings in the stage of their design. In the work, a fractographic analysis of ionic nitrogen samples from aluminum pistons of agro-industrial machinery engines using a method of raster electron microscopy on a microscope Micro analyzer "Samssn-4DV" was performed. Determination of the chemical composition of the surface of the samples, as well as various phases, imperfections and inclusions was carried out in this paper using the X-ray spectral microanalysis method (RSMA). It has been established that the mechanism of kinetics of the process of destruction is reduced to the gradual growth of microcracks to a critical size as a result of the rupture of atomic bonds in the vertex of the crack with stresses, which exceeds the conditional limit of the content of the "base-coating" composition. There is an emergence and growth of the same types of cracks. Then the cracks are increasingly revealed and the length and depth increases. The intensive local oxidation of the base in the area of the coating defect leads to a reduction in the cross-section and the growth of acting stress. The consequence of this is an increase in the creep speed, which in turn leads to the development of the initial defect and to the progressive process of destruction in non-additive operating factors. It has been found that the bases defects are destroying the coating. In addition, it has been found that the deformation of the sample is carried out at the expense of the displacement processes. Confirmation of this is the characteristic lines of Chernova-Leuders. Conclusions. It has been shown that the mechanism of destruction process is reduced to the gradual growth of microcracks as a result of the rupture of atomic bonds in the vertex of the crack at strains, which exceeds the conditional line of fluidity of the "base-coating" composition. The presence of areas of the base is established, which as a result of a violation of the strength of the strengthened surface layer interact with the environment and affect the increase of plasticity due to the disclosure of defects. This increases the creep speed, which in turn leads to the progressive process of destruction in the simultaneous operation of operational factors.

Analysis of piston microstructure in the most critical zones

This paper presents the results of testing the microstructure in the most critical zones of pistons made of aluminum piston alloys. The paper analyzes the shape, size and distribution of primary Si crystals and other phases in three most important piston zones (the edge of the combustion chamber, the area of rings groove and piston pin boss). The phase stoichiometry was identified by comparing the results of EDS analysis with the results reported in the studied literature. The results show that the necessary size, shape and distribution may be obtained in specific zones if appropriate solidification conditions are provided that are necessary for the formation of specific phases.

Improving the quality level in the automotive industry

Abstract Currently, effective quality management of manufactured products is a factor determining the development of manufacturing companies. However, the identification of the source of non-compliance and the analysis of its causes are sometimes underestimated and are not followed by appropriate methodologies. The study aimed to streamline and improve the production process of aluminium pistons for passenger cars by solving the problem related to a significant number of non-compliant products. The analysis of types of nonconformities identified through penetration testing was performed. The use of histogram, brainstorming session and Pareto-Lorenz diagram was proposed, which allowed identifying the causes of the problem. The presented solution shows the practical effectiveness of a sequence of selected instruments to solve production problems. The proposed sequence of methods can be implied in other qualitative analyses in different companies.

Production of high-load diesel engines

Analysis of the development of modern engine building has shown that internal combustion engines have a leading position. It is fair to say that there are attempts to change this trend - for example, the serial electric car Tesla. But the oil industry is now a key sector of the global economy, and the dominance of internal combustion engines may remain the main one for many decades. The article analyses steel and aluminum pistons manufactured with application of technologies adapted to customer requirements. These technologies allow creation of heavy duty engines with maximum reliability and optimal combination of characteristics, reduction of emissions of harmful substances and reduction of fuel consumption.

Hardness and Elastic Modulus of Al-Based Composite Developed from Aluminium Piston Scraps Using Alumina and Snail shell as Reinforcements

This paper presents the relationship between the Young’s modulus and hardness of composites developed from recycled aluminium pistons reinforced with alumina and snailshells. The percentages of alumina and snailshells were kept within the range of 0-30 and 0-10 wt.%, respectively. Experiments were designed using response surface methodology (RSM) to evaluate the influence of the reinforcements on the tensile, hardness and Young’s modulus of the composites. The theoretical hardness was analyzed from the ratio of indentation hardness to indentation modulus while the Young’s modulus was evaluated from the composite equations. The results indicate that an increased fraction of the hybrid reinforcement does not necessarily translate to higher hardness value and Young’s modulus. The sample with the best characteristics has a tensile strength of 172.5 MPa, modulus of resilience of 28.28 GPa and hardness value of 44.9 RHN. The average experimental Young’s modulus of the samples is about 30% of the theoretical value of 86.5GPa while experimental hardness value of 44.90 is about twice that of the theoretical value. The discrepancy between the experimental and theoretical modulus is due to the assumption of a perfect crystal for the former as against polycrystalline crystals. The two samples with the highest modulus of resilience were chosen and further characterized. Scanning Electron Microscope images showed that the fillers in the two samples were well bonded with the aluminium matrix. Keywords - Mechanical Properties, Casting, Aluminum composite, Alumina and Snailshells

Моделирование напряженно-деформированного состояния поршня дизеля с учетом неупругих деформаций

The failure of aluminum pistons of diesel engines is often associated with formation of cracks originating at the bowl rim. The appearance of cracks is a consequence of thermal fatigue of the material due to low-frequency cycles of heating and cooling of the piston during the engine start-up, operation at various speed and load conditions, and subsequent shutdown. To assess the lifetime of the bowl rim, it is necessary to simulate non-isothermal elastoplastic deformation of the alloy using material plasticity and creep models available in finite element analysis software (e.g. ANSYS). This paper presents the results of uniaxial tensile and creep tests of proportional specimens made from piston blanks of the V-type diesel engines YaMZ-658. The piston material is AlSi12CuNiMg silumin alloy. The article describes methods for determining constants in plasticity and creep models. The results of numerical simulation of the piston’s stress-strain state for the start — nominal power mode — stop cycle using the finite element method are presented. Conclusions about the presence of plastic and creep strains at the piston edge are drawn.

Piston-Pin Rotation and Lubrication

The rotational dynamics and lubrication of the piston pin of a Gasoline engine are investigated in this work. The clearance plays an essential role for the lubrication and dynamics of the piston pin. To obtain a realistic clearance, as a first step, a thermoelastic simulation is conducted for the aluminum piston for the full-load firing operation by considering the heat flow from combustion into the piston top and suitable thermal boundary conditions for the piston rings, piston skirt, and piston void. The result from this thermoelastic simulation is a noncircular and strongly enlarged clearance. In the second step, the calculated temperature field of the piston and the piston-pin clearance are used in the simulation of the piston-pin journal bearings. For this journal bearing simulation, a highly advanced and extensively validated method is used that also realistically describes mixed lubrication. By using this approach, the piston-pin rotation and lubrication are investigated for several different operating conditions from part load to full load for different engine speeds. It is found that the piston pin rotates mostly at very slow rotational speeds and even changes its rotational direction between different operating conditions. Several influencing effects on this dynamic behaviour (e.g., clearance and pin surface roughness) are investigated to see how the lubrication of this crucial part can be improved.

Quality Management of Aluminum Pistons with the Use of Quality Control Points

Abstract The publication analyses the way of managing and improving the quality of the production process of aluminum pistons for internal combustion engines. The aim of the article is to propose a method of analysis of the effectiveness of individual control methods used in the process of controlling the aluminium piston. Thanks to the location of a control point with the highest share of product non-compliance detection in the production process, it is possible to reduce quality control points by less effective points, which will contribute to lower costs or shorten the time of production processes. In view of the increasing demands on the efficiency of the checkpoints for components in internal combustion engines, the issue is important and topical.

Correlation between theoretical and experimental hardness, elastic modulus of discarded aluminium piston reinforced with zirconium diboride and snail shells

Aluminium metal matrix composites have gained a lot of attention because of their outstanding properties making them useful for aerospace, automobile and marine applications. Composites are replacing metals as structural materials, and a detailed study of the relationship between hardness and Young’s modulus becomes essential. In this paper, the correlation between hardness and elastic modulus of discarded aluminum pistons reinforced with zirconium diboride and snail shells is presented. The theoretical hardness was determined from the ratio of indentation hardness to indentation modulus while elastic modulus was evaluated based on composite equation. The results indicated that hardness and elastic modulus increased with the weight percentage of the composites while the resistance to plastic deformation H3/E2 increased with H. The wide discrepancy between the theoretical and experimental Young’s modulus is attributed to the fact that theoretical elastic moduli were obtained from perfect/single crystal materials while experimental values are obtained from polycrystalline/imperfect crystals. The calculated Young’s moduli obtained through mixture rule range from 64 to 92 GPa which are higher than 69 GPa of aluminium alloy. It is therefore evident that the composite materials can be used for engineering applications.

Effect of Reinforcements and Abrasive Size on High-Stress Tribological Behaviour of Aluminium Piston Matrix Composites

The aim of this research paper was to look into the high-stress abrasive or sliding wear of the LM13 and ADC12 alloy and its composites as LM13-7% SiC, LM13-7% TiB2, ADC12-7% SiC and ADC12-7% TiB2 reinforced with SiC and TiB2 particles. The high-stress abrasive test was examined at various emery grit meshes as 180, 220, 320 and 400 correspond to 88, 60, 44 and 37 micron, and a load of 20 N and 30 N was applied for scratching distance of 200 m and 300 m at a sliding speed of 5.2 m/s. Smooth wear track or channel was shown in case of alloys. Wider and discontinuous wear tracks were depicted in case of composites due to inclusion of strengthen particles. Alloys showed less frictional heating as compared to their composites and among composites titanium diboride amalgam showed more frictional heating as compared to silicon carbide strengthen composites. There was rapid increase in frictional heating in composites as compared to alloys due to presence of hard particles. Frictional heating increased on inclusion of ceramic particles. Experiment result showed that titanium diboride composites in aluminium base alloy considered excellent material for tribological and general purpose engineering application.

Comparative analysis of different materials for piston and justification by simulation

The objective of this paper is stress distribution and thermal analysis of Aluminum and Magnesium alloy pistons. At room temperature, the strength of WE43A is lower than that of Al-7Si piston, but at elevated temperatures, WE43A can withstands more efficient due its mechanical and thermal properties than that of Al-7Si. After performing analysis, results in the form of graphs signify that total deformation in WE43A is directly proportional to an increase in pressure, due to which magnesium is a softer metal than the AL-7Si. Total heat flux of AL-7Si is lower than that of WE43A, thus magnesium alloy pistons perform much more efficient at higher temperature range.

Constitutive Behavior of an AA4032 Piston Alloy with Cu and Er Additions upon High-Temperature Compressive Deformation

Aluminum piston alloys of the AA4032 type are produced by direct-chill (DC) casting and subsequent forging; therefore, it is important to understand their thermomechanical behavior. In recent years, it was shown that additions of Cu and Er could improve mechanical properties of these alloys at room and high temperatures. In this work, we studied the constitutive behavior of AA4032-type alloys with and without Cu and Er additions. The experimental true stress–true strain curves were obtained by compression tests under various temperatures [683 K to 723 K (410 °C to 450 °C)] and strain rates (0.01 to 10 s−1) to determine constitutive parameters [strain-rate sensitivity, activation energy, and Zener–Hollomon (Z) parameter] for the hot deformation behavior of AA4032-type piston alloys with and without additions of Cu and Er. The flow stress decreased with increasing deformation temperature and decreasing strain rate. The results also showed that increasing the Cu content increased the flow stress over the applied range of deformation conditions due to solid-solution strengthening and the formation of primary Si particles, which led to an increase in the activation energy during hot deformation. Moreover, the main microstructural damage in the AA4032 alloy with 3.5 pct Cu was predominantly due to the cracking of primary Si particles. Additions of 0.4 pct Er and 3.5 pct Cu lower the activation energy of deformation, Q, as compared to the base alloy and the alloy with 3.5 pct Cu. The microstructures in the deformed specimens consisted of subgrains, recrystallized grains, and fine eutectic phases. The alloys containing Er demonstrated more polygonized grains at a low strain rate than the alloys without Er, indicating that Er hindered recrystallization development. The peak stress of the AA4032 alloy with 3.5 pct Cu alloy was higher than for the base AA4032 alloy and for the AA4032 alloy with 3.5 pct Cu and 0.4 pct Er additions, which was attributed to the prevalence of the work-hardening mechanism over the softening mechanism.

Quantitative evaluation of n-butane concentration on knock severity of a natural gas heavy-duty SI engine

Knocking combustion of a natural gas spark ignition engine with the addition of n-butane was investigated. Specially, the effects of n-butane concentration on knock severity were quantitatively evaluated with engine full-load at various engine speeds. The results show that with an increase in n-butane concentration, the peaks of in-cylinder pressure and heat release rate increase, combustion duration is shortened, and CA50 is advanced. At high speeds, n-butane concentration has a more pronounced influence on combustion and knock. With increased n-butane concentration, cyclic pressure traces oscillate more and more violently, the maximum pressure rise rate (MPRR) and the maximum amplitude of pressure oscillation (MAPO) in some cycles increase significantly. Here the MPRR threshold of light knock cycle is defined at 1.0 MPa/CAD, and the one of heavy knock cycle is 4.0 MPa/CAD. Meanwhile the MAPO threshold of light knock cycle is set at 0.1 MPa, and the one of heavy knock cycle is 0.3 MPa. Based on these thresholds and the probability of knock severity, light and heavy knock conditions are identified. Moreover, the combustion close to light knock may increase thermal efficiency, and heavy knock has caused the erosion of aluminum piston crown and top land in the experiment.

Suspension Plasma-Sprayed Thermal Barrier Coatings for Light-Duty Diesel Engines

Demands for improved fuel efficiency and reduced CO2 emissions of diesel engines have been the driving force for car industry in the past decades. One way to achieve this would be by using thermal spraying to apply a thermal insulation layer on parts of the engine’s combustion chamber. A candidate thermal spray process to give coatings with appropriate properties is suspension plasma spray (SPS). SPS, which uses a liquid feedstock for the deposition of finely structured columnar ceramic coatings, was investigated in this work for application in light-duty diesel engines. In this work, different spray processes and materials were explored to achieve coatings with optimized microstructure on the head of aluminum pistons used in diesel engine cars. The functional properties of the coatings were evaluated in single-cylinder engine experiments. The influence of thermo-physical properties of the coatings on their functional properties has been discussed. The influence of different spray processes on coating formation on the complex piston head profiles has been also discussed. The results show that SPS can be a promising technique for producing coatings on parts of the combustion chamber, which can possibly lead to higher engine efficiency in light-duty diesel engines.

Benefits and Application Bandwidth of Phenolic Piston Material in Opposed Piston Calipers

<div class="section abstract"><div class="htmlview paragraph">The use of reinforced phenolic composite material in application to hydraulic pistons for brake calipers has been well established in the industry - for sliding calipers (and certain fixed calipers with high piston length to diameter ratios). For decades, customers have enjoyed lower brake fluid temperatures, mass savings, improved corrosion resistance, and smoother brake operation (less judder). However, some persistent concerns remain about the use of phenolic materials for opposed piston calipers. The present work explores two key questions about phenolic piston application in opposed piston calipers. Firstly, do opposed piston calipers see similar benefits? Do high performance aluminum bodied calipers, where the piston may no longer be a dominant heat flow path into the fluid (due to a large amount of conduction and cooling enabled by the housing), still enjoy fluid temperature reductions? Are there still benefits for judder with the much shorter length to diameter ratio the pistons have in these applications? Secondly - it is clear that the much shorter length to diameter ratio of the piston in opposed piston calipers will result in significant increases in contact stress on the piston material at its contact points to the bore, when it is pressurized against pads with significant taper wear - will the phenolic material have adequate durability to withstand this? Can a simple “application guideline” for phenolic pistons be defined, potentially based on piston diameter (governing peak clamp load) and length to diameter ratio (which determines the correlation between clamp load and contact stress in the piston material at the bore contact points)? To address the first question, a battery of comparative tests was run on a high performance 6 piston aluminum-bodied brake calipers with high performance low-metallic brake pads and a large 18” wheel envelope two piece, cast iron plate and aluminum hub rotor. Fluid consumption, drag, brake torque variation, and fluid temperatures were measured through tests designed to exercise these behaviors, with both the production aluminum pistons and prototype phenolic piston calipers. The second question was explored through lab-based durability testing, abusive inertia dyno testing, and analysis of parts failed during testing. Pistons of the same phenolic material (Durez 29504B) were prototyped in opposed-piston caliper configurations in two sizes (51mm and 34mm) and tested to failure. The analysis of the data changed the authors’ initial thinking substantially about the failure mechanics of the piston in severe use, but still resulted in a simple, free body diagram based application guideline and a clear path for future work.</div></div>

About Structural and Thermal Analysis of Diesel Engine Piston Using Ansys Software

The main role of the piston is to vary the dimensions of the combustion chamber in internal combustion engine. The piston is in contact with the hot gases resulting from combustion. In addition to thermal stresses, depending on the operating mode of the engine, the piston is required to alternate the inertial force. Therefore, the steel piston undergoes due to high inertial forces, and lightweight aluminium pistons cannot operate at high temperatures. In order to combine the advantages of the two types of materials it has been chosen the constructive design of the bimetal pistons. This paper aims to compare the performances of steel pistons and bimetal pistons using the Ansys software.

Numerical and experimental investigation of a piston thermal barrier coating for an automotive diesel engine application

This paper investigates the potential of coated pistons in reducing fuel consumption and pollutant emissions of a 1.6 l automotive diesel engine. After a literary review on the state-of-the-art of the materials used as Thermal Barrier Coatings for automotive engine applications, anodized aluminum has been selected as the most promising one. In particular, it presents very low thermal conductivity and heat capacity which ensure a high “wall temperature swing” property. Afterwards, a numerical analysis by utilizing a one-dimensional Computational Fluid Dynamics engine simulation code has been carried out to investigate the potential of the anodized aluminum as piston Thermal Barrier Coating. The simulations have highlighted the potential of achieving up to about 1% in Indicated Specific Fuel Consumption and 6% in heat transfer reduction. To confirm the simulation results, the coated piston technology has been experimentally evaluated on a prototype engine and compared to the baseline aluminum pistons. Despite the promising potential for Indicated Specific Fuel Consumption reduction highlighted by the numerical simulation, the experimental campaign has indicated a slight worsening of the engine efficiency (up to 2% at lower load and speed) due to the slowdown of the combustion process. The primary cause of these inefficiencies is attributed to the roughness of the coating.

Effect of Friction conditions on Material Flow in FE Analysis of Al Piston Forging Process

In the hot forging process of aluminum piston using water-soluble lubricants, the lubricant layer is often peeled off due to excessive deformation of the material during forming, which may result in direct contact between the material and the die, thereby partially increasing the friction. The constant friction in the Finite element (FE) analysis of this process sometimes results in a completely different result from the actual material flow. Therefore, this study was designed to investigate the friction condition to accurately predict the material flow in the FE analysis. The FE analysis was performed for various material temperatures and friction parameters and the proper friction condition was also derived to remove forging defects. Finally, the forging test was carried out for the initial specimens produced by three different methods to verify the analytical results and eliminate the forging defects. The results showed that the friction depends on the effective strain in the FE analysis and the critical value to increase friction is approximately 1.5–1.8. In addition, among the three different specimens, the shot peened specimen can remove the forging defect by increasing the amount and uniformity of the lubricant on its surface.