Piston Crowns Research Articles

A hybrid GRA-FIS based genetic algorithm and simulated annealing approach for camshaft material optimization using finite element analysis

Failures in the camshaft drive can allow the valves to contact the piston crowns, which can result in significant internal damage. Most of the researchers have reported that aluminium–silicon carbide composite has not only proven to be lightweight but also resulted in lower deformation and better fatigue strength when compared to other alloys or steel. No predictive approach has been taken to predict more durable materials and the optimum working condition of camshafts using optimization methods. As a result, in order to fill such gaps, this study focuses on the design of camshafts made of various materials. In order to reduce the maximum stress, maximum deformation, and maximum strain obtained, this study focuses on optimising the camshaft by choosing the best material and loading conditions. The Taguchi L16 orthogonal array design and ANSYS 17.2's were used for the analysis. Finite element analysis was used for static structural analysis, and the findings produced by cast iron camshafts were compared to aluminium–silicon carbide composite composites. Later on, multi-objective optimization was tested using grey relational analysis in conjunction with a fuzzy inference system. The simulated annealing and genetic algorithm approaches were also used to forecast optimized results. It resulted that aluminium–silicon carbide composite 40% composite is the most suitable material. The most important factor was determined using an analysis of variance, followed by confirmatory tests. It showed that loading condition was the most significant factor.

Cold-Sprayed Multilayer Thermal Barrier–Catalytic Coatings for Engine Pistons: Coatings Design and Properties

Yttrium-stabilized zirconia thermal barrier coatings (TBCs) of combustion chambers and piston crowns are used most frequently to increase the chamber temperature and the internal combustion engine efficiency. The development of multilayer metal matrix composite coating is of great importance to diminish the ceramic thermal barrier coating’s brittleness and susceptibility to degradation providing the similar thermal insulation. Our group is developing multilayer TBCs based on intermetallic (Fe-Al) compounds combined with alternating zirconia-based layers made by low-pressure cold spraying (LPCS) and sintering. The Fe-Al intermetallic phase was synthesized during reaction sintering of stainless steel and Al particles in the powder layer previously obtained by cold spraying. A double-nozzle low-pressure cold-spraying gun was used to deposit two layers (stainless steel and Al-YSZ) per one track. The effect of the breaking of the brittle ZrO2 particles due to impingement with the substrate results in the formation of a relatively homogeneous structure with ZrO2 particle size of 3–10 μm. Cold-spray deposition of additional Cu-Ni-Graphene catalytic layers on the TBCs is developed to improve performance and emissions of engines. The microstructure, thermal conductivity, thermal shock behavior and microhardness of TBCs were examined and discussed.

Optimization of Dual Coating Using Electroless Ni‐P‐Nano‐TiO2 and Plasma Yttria‐Stabilized Zirconia on Piston Crown and Cylinder Liner in CI Engine

Most of the automobile engine components are made up of cast iron because of its low cost, damping characteristics, castability, and commercial considerations. In modern days, the blended biodiesels are introduced into the CI engine to reduce the usage of petroleum fuels. The following problems are identified in utilizing the biodiesels, they are lower efficiency, power, wear in the engine cylinder and piston crowns, more emission from the exhaust, and performance. To overcome the wear problem in cylinder liner and piston crown, the dual coating is developed using electroless coating and plasma spray coating, and this deposit acts as a thermal barrier to the engine. The electroless Ni‐P‐TiO2 composite coating process parameters are optimized using the Taguchi technique with multiresponse grey relational analysis. The plasma spray coating is developed over electroless Ni‐P coating using Yttria‐stabilized Zirconia for the total thickness of 2 mm. The coated components are installed in the CI engine for further testing and analysis. The morphology of the coated surfaces is tested using the scanning electron microscope. The optimization process used to improve the Ni‐P coating thickness, surface roughness, and thermal resistance of the engine components. Also, the performance and emissions in the engine are reduced significantly. The emission from the CI engine such as NOx, COx, and HC are reduced significantly. The emissions of CI engine such as NOx, CO2, CO, and HC of the noncoated engine shows higher, and EPSCE engine condition shows less pollution. The percentage of improvement in terms of emissions are 27%, 70%, 6.4%, and 21%, respectively. The performance is improved to 3% and 27.8%, respectively, for specific fuel consumption and brake thermal efficiency.

Simulation-Based Analysis of Piston Strength of a Modified Dual Fuel Diesel Engine

New study in converting of a diesel engine to be dual fuel capability has been developed from conventional one. The use of CNG as fuel results in lower efficiency and the power output is also decreased. In order to return the engine performance, the piston crown has been modified. The consequential of the piston crown modification causes the increase of the compression ratio. This research mainly investigates how the piston engine as the weakest material on the combustion chamber can resist the additional strength that may occurred. Four modification models have been generated and numerically tested. The validated models will be simulated to certain conditions that refer to the new combustion processes under different gas/diesel oil compositions. The material strength of the modified piston engines investigated to understand the acceptance of the modified engine. The simulation results show that the four modified piston crowns are safe without any predicted overstress and excessive deformation.

Comparative evaluation of 4-cylinder CI engine camshaft based on FEA using different composition of metal matrix composite

The Camshaft is a vital part of the Internal Combustion engine of automobiles. It functions as a timing mechanism that controls the opening and closing of the inlet and exhaust valves, as well as the valve overlap that occurs at the TDC of the exhaust stroke. The camshaft is made up of several journals that run on bearings within an engine. The camshaft is bound to rotate with the crankshaft by either a set timing gear, timing belt, or timing chain. As the camshaft drive fails, the valves and piston crowns come into contact, causing extensive internal damage. For high-speed diesel engines (Compression Ignition), power impulses have a greater value than spark-ignition engines in multi-cylinder configurations. In this study, a comparative analysis of an existing automobile camshaft of four-stroke, a four-cylinder Compression Ignition (CI) engine made of Cast Iron was carried out with different compositions of metal matrix composites. For this condition, the outcomes were taken as Von-Mises stresses and displacement values for the static state of the camshaft. The modal analysis (Free vibration) was performed using ANSYS after the static analysis results were obtained. Finally, comparing all the results obtained for different materials, the AlSiC 20% metal matrix composite has been recommended as the most suitable material for the production of camshafts which can replace cast iron because of its similar behavior as to cast iron. This will aid in the development of more precise camshafts, which will be useful for larger displacement engines.

Theoritical modelling and finite element analysis of automobile piston

Automobile engines have with time witnessed a favorable change with respect to fuel economy, passenger comfort, environment, and so on. The change continues with every manufacturer and researcher striving toward excellence. Pistons and their ring assembly are one of the important elements in whole engine assembly, which have metamorphosed to suit the current requirement. Improvements in design, geometry, and material have not only reduced the inertia forces but also increased the time interval between overhauls. The modification of piston crowns to introduce swirl by squish effect and material coating techniques have enhanced the features of a piston. In fact, engines today last their useful life without any significant maintenance other than renewal of oil and filters. Piston rings too have reduced in numbers and are designed to meet its functional requirement. Piston is part of corresponding engines, corresponding pumps, fuel compressors, pneumatically-pushed conical, amongst different similar mechanisms. It is the moving detail that’s had through cylindrical tube, made fuel tough through disc. The piston transforms the energy of the growing gasses proper into mechanical strength. The piston flights inside the cylinder lining or sleeve. Pistons are regularly made from aluminum (Al) or actors iron alloys. The primary reason of the task is to format a piston for 1300 cc diesel motor for two materials Cast Iron (CI) and also Light Weight aluminum Alloy. The designs of the piston are designed utilizing 3d model software program. The designs are reviewed through architectural and additionally thermal assessment through using pressure and temperature stages mainly. The result is evaluated via checking the stress, model, thermal slope and thermal trade to select the very top notch fashion of the piston.

The influence of ceramic-coated piston crown, exhaust gas recirculation, compression ratio and engine load on the performance and emission behavior of kapok oil-diesel blend operated diesel engine in comparison with thermal analysis.

In this work, the development and usability of kapok oil in diesel engine was intended. With this purpose, the piston crowns are coated with mullite-lanthanum (ML) ceramic composite at varying compositions in order to reduce the heat rejection during combustion process. The kapok oil is blended with diesel fuel consisting of (20% kapok oil-80% diesel) volumetrically named B fuel. The B and diesel (D) fuels are taken for the engine performance test with different coated piston (ML1, ML2, and ML3) and exhaust gas recirculation (EGR-10%, 20%, and 30%), compression ratio (CR-16, 17, and 18) and engine load (50%, 75%, and 100%). Also, the engine performance study on brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), hydrocarbons (HCs), oxides of nitrogen (NOx), carbon monoxide (CO), smoke opacity, and numerical study using ANSYS software is carried out. When operated with ML2-coated pistons with B fuel, maximum BTE value of 29.2%, minimum BSFC value of 0.224 kg/kW-h, CO emission of 0.2%, and smoke opacity of 39 ppm were observed. The results showed that ML2-coated piston considerably improved the performance of the test engines when compared with ML1 and ML3 coatings. Except for NOx emission, all other pollutant emission values were reduced. The numerical analysis using ANSYS software for ML2-coated pistons showed better retention of in-cylinder chamber temperature.

Повышение долговечности головок поршней судовых малооборотных дизелей технологическими методами

Повышение долговечности головок поршней судовых малооборотных дизелей технологическими методами

A Computational Fluid Dynamics Study of the Swirl Generation Analysis in Four-stroke Direct Injection Engine

In this study, the Computational Fluid Dynamics (CFD) simulation to investigate the effect of two piston crowns to the field inside the combustion chamber of a four-stroke direct injection automotive engine when at the motoring condition. The field flow into the chamber for air-fuel mixing to obtain the better swirl ratio, engine combustion, performance and efficiency when the swirl is appeared. So this analysis is important on this study of the effect of the piston shapes to the fluid flow and the air into the cylinder, The behaviors of fluid flow occurred inside combustion chamber is represented by two parameters which influences the air streams to the cylinder during intake stroke and improves the swirl of the air-fuel to produce better air-fuel mixing during the compression stroke. To investigate the effect of air-fuel swirl when change the intake valves conditions and the piston crown shapes. The numerical simulation analysis can be showed the swirl ratio when the air-fuel into the combustion chamber that the condition of the intake valves and the shapes of the piston crown in the combustion chamber by use the Computational Fluid Dynamics (CFD) mode.

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.

Heat Transfer Characteristic of Thermal Barrier Coated Piston Crown for a Compressed Natural Gas Direct Injection Engine

Compressed natural gas with direct injection (CNGDI) engine produces high temperature and pressure ultimately leading to high thermal stress. The piston crown material fails to withstand high temperature and operate ineffectively due to improper heat transfer. By insulating the surface namely; thermal barrier coating (TBC) such as ceramic based yttria partially stabilised zirconia (YPSZ), heat transfer to the piston might be reduced and lead to improvement of piston durability. Hence, in this research, YPSZ/NiCrAl coating was utilised to differentiate with the uncoated piston crowns in terms of the ability to reduce thermal stresses to the piston using finite element method and burner rig test. Several samples of AC8A aluminium alloy piston crowns were coated with bonding element of NiCrAl and ZrO2-7.5Y2O3namely the YPSZ as the top coat by using air-plasma spraying technique and were assessed by burner rig test. The results exhibited the durability of the YPSZ/NiCrAl coating could withstand the test and the heat flux for the YPSZ/NiCrAl-coated piston crown was about 98% reduction compared to the uncoated piston crown. Also, the lower the gradient value of the heat flux, the higher the heat resistance.

The Effects of Thermal Barrier Coatings on Diesel Engine Performance and Emission

The purpose of this paper is to determine the effect of coating thickness on performance and emission of a diesel engine including comparisons with results from an uncoated piston diesel engine. Primarily three piston crowns were coated with Al2O3 (bond coat) of 100 μm thickness each by using Plasma spray coating technique. Then these piston crowns were coated with partially stabilized zirconia with a thickness of 250, 350, 450 μm respectively by using the same technique over the bond coat. These pistons inserted into the cylinder of a diesel engine one by one to collect the combustion and emission data. Then these data were compared with standard diesel engine. It was observed that the thermal efficiency increased with increasing load levels, whereas specific fuel consumption reduced with increasing load. However, it was observed that harmful gases and particulates like CO, smoke and HC were reduced in case of all types of coated piston engine with the increase of load. Increased amount of NOX emission was reported during the experimentation.

High Temperature Fatigue Behavior of Eutectic Al-Si-Alloys Used for Piston Production

Pistons of IC engines are typically subjected during operation to high cycle fatigue loading cycles at high temperatures (up to 350°C) in areas facing the combustion chamber. During operation the high temperature exposure results in a progressive loss of fatigue strength of the material at the weakest areas of the piston and may eventually results in a premature failure by crack initiation and propagation. The quantification of the temperature effect on fatigue strength inevitably require experimentation since such data are scarce.An extensive fatigue testing program of eutectic Al-Si alloys at room temperature and at several high temperatures (250°C, 300°C and 350°C) is reported. Specimens were extracted from piston crowns and tested in a rotating bending test machine. The resulting fatigue strength loss at 107 cycles is quantified by a staircase approach. The influence of the test temperature is investigated in terms of chemical composition, process route and of mechanisms of fracture observed in the broken specimens.

Effect of Extreme Temperatures on Coated Piston Crown for CNGDI Engine

Due to high temperature and less proper heat transfer, the material of piston crown in an engine of compressed natural gas with a direct injection system (CNGDI) may lead to high thermal stresses and fails to withstand high temperature and operate effectively. By insulating with thermal barrier coating (TBC) such as ceramic-based yttria partially stabilised zirconia (YPSZ), heat transfer to the piston might be reduced and lead to improvement of piston durability. Hence, in this research, YPSZ coating was utilised to differentiate with the uncoated piston crowns in terms of the ability to reduce thermal penetration to the piston. A detailed finite element analysis (FEA) was carried out to determine the location of hotspots via profiles distribution of thermal. In short, it was observed that hotspots were mainly concentrated at the piston bowls rim. The heat flux for the YPSZ/NiCrAl-coated from FEA exhibited about 98% reduction compared to the uncoated piston crown.

Experimental Study of Ceramic Coated Piston Crown for Compressed Natural Gas Direct Injection Engines

High temperature produced in a compressed natural gas with direct injection system (CNGDI) engine may contribute to high thermal stresses. Without appropriate heat transfer mechanism, the piston crown would operate ineffectively. In this work, bonding layer NiCrAl and ceramic based yttria partially stabilized zirconia (YPSZ) were plasma sprayed onto AC8A aluminum alloy CNGDI piston crowns and normal CamPro piston crowns in order to minimize thermal stresses. Several samples were deposited with NiCrAl bonding layers prior to coating of YPSZ for comparison purpose with the uncoated piston. The performance of the coating against high temperature was tested using a burner rig. The temperatures on the top of piston crown and piston underside were measured. Finally, the heat fluxes of all conditions of piston crown were calculated. In short, the YPSZ/NiCrAl coated CNGDI piston crown experienced the least heat fluxes than the uncoated piston crowns and the coated CamPro piston crown, giving extra protection during combustion operation.

Atomization of liquid droplets on surfaces exposed to moving shock waves

Many engineering applications involve the stripping of liquid droplets from surfaces, one example being the entrainment of surface fuel from the inlet valves, ports, cylinder walls and piston crowns of internal combustion engines during the induction process. This configuration is likely to exhibit differences from the more commonly studied case of suspended droplets. In order to study the atomization of liquids from surfaces, shock waves at low Mach numbers (M = 1.05 and 1.12) have been used in the present work to initiate the flow over water droplets with visualization obtained from shadowgraph photographs, high-intensity flash photography and a CCD camera. Visualization paths both normal and angled at ±45° to the flow were used in order to obtain improved examination of the atomization details. Surface wave formation and a specific pattern of droplet distortion followed by stripping, was observed. There are similarities in the processes to those of suspended droplets that are modified by the boundary layer effects. At the Weber numbers considered, a cave-like formation occurs near the wall due to surface flow around the droplet with a major liquid flow directed tangentially across the air flow towards the cave peak where bag or chaotic type break-up and stripping takes place.

Day-to-Day Challenges of a Shipping Company From the Technical Department’s Point of View: Lessons Learned

Working for one of the largest shipping companies in Greece is not an easy task. The challenges from the day-to-day vessel operation never stop and the maritime environment, which grows more challenging by the day, demands that the technical department is on a constant state of alert. The paper discusses the lessons learned from the many years of the authors' combined experience in the technical departments of a bulk carrier operator and of its tanker counterpart. The most interesting and diverse cases are outlined together with the conclusions and the necessary alterations to the procedures and work practices established as a result of the experiences gained. The following cases are examined:propeller damage on a Capesize bulk carrier from inherent casting defects,main engine camshaft problems originating from initial poor design,cracking of main engine bedplate bearing girders on a very large crude carrier (VLCC) attributed to unauthorized repairs and casting defects,failure cases of fitted bolts in marine applications,premature failure of main engine piston crowns, andsea chest ballast valve problems on a VLCC attributed to poor detail design.

SANS study of the precipitates microstructural evolution in Al 4032 car engine pistons

Small angle neutron scattering (SANS) technique has been used to study the microstructural evolution of precipitates in real pistons made from commonly used AlSi12CuNiMg alloy. The experiment was performed on new and worn out piston crowns. SANS curves were measured at five different points (possible critical locations) of both pistons. At the central points of the new sample an isotropic scattering was observed, while in the lateral parts of the piston the scattering became anisotropic, indicating the presence of a manufacturing induced texture. The Al–Mg–Si alloys exhibit mechanical properties, which are highly sensitive to thermal treatments. The operating temperature is usually very close or, in certain parts of the crown, can exceed the ageing temperature. A comparison of the ageing treatment-caused alteration of mechanical properties with the changes of the precipitates structure is reported.

Performance and emissions characteristics of a partially insulated gasoline engine

This paper presents the work continued from the previous study on a low heat rejection (LHR) engine. Instead of using a single-property yttria-stabilized zirconia (YSZ) coating to achieve the thermal barrier for the piston crown, a varying-properties functionally graded material (FGM) was used in this study. Extensive experiments were conducted on a 3-cylinder SI Daihatsu engine with all piston crowns coated with a layer of ceramic, which consists of zirconia and yttria with varying compositions along its thickness. Measurements of engine performance, in particular its fuel consumption and emissions characteristics, were made before and after the application of FGM coatings onto the piston crowns. To gain more insight of improved engine performance, in-cylinder pressure measurements were conducted which provide direct comparison of pressure–volume diagrams between baseline and that coated with FGM.

The Effect of Thermal Barrier Coated Piston Crown on Engine Characteristics

While there have been numerous research papers in recent years describing the theoretical benefits obtained from the use of ceramic components in reciprocating engines, the amount of literature that describes practical results is very limited. Although successes have been reported and ceramic components are now in service in production engines, mainly for reduced in-cylinder heat rejection, many researchers have experienced failures or a drop in engine performance. This article presents the work completed on a low heat rejection engine. Extensive experiments were conducted on a three-cylinder SI Daihatsu engine with piston crowns coated with a layer of ceramic, which consisted of yttria-stabilized zirconia (YSZ). Measurement and comparison of engine performance, in particular fuel consumption, were made before and after the application of YSZ coatings deposited onto the piston crowns. The details of the cylinder pressures during the combustion process were also investigated.