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Design and analysis of gasket sealing of cylinder head under engine operation conditions
Abstract
To avoid the escaping gas from the engine affecting the overall performance of the engine during operation, both the proper pre-stressing force of the bolts as well as the gasket design are critical factors in enhancing the efficiency of the sealing of the gasket. In this investigation, both the distribution of the contact pressure on the gasket, and the stresses of the cylinder head at different loading conditions, such as cold assembly, hot assembly, cold start, and hot firing, are explored by numerical calculation based on the finite element method (FEM). The results reveal that the efficiency of the sealing of the head gasket depends on the pre-stressing force of the hold-down bolts, without taking into consideration any thermal stresses resulting from the temperature distribution in the cylinder head. However, the location of maximum contact pressure on the gasket is transformed when the thermal loading is taken into account. In addition, this research also conducts the parametric analyses for the pre-stressing force of the bolts and compares the differences between cold assembly and cold start conditions.
... Engine cylinder head-block connections are most often analyzed using the finite element method [1]. In the subject literature, the following models of the connection can be found: a) plain models [2,6], b) spatial models [3,4,5,12]. ...
... Połączenia głowicy z blokiem silnika najczęściej analizuje się przy użyciu metody elementów skończonych [1]. W literaturze dotyczącej tego tematu stosuje się następujące modele połączeń: a) płaskie [2,6], b) przestrzenne [3,4,5,12]. ...
... e) the distribution of contact pressure on the gasket [12]. ...
The paper presents modeling and calculations of multi-bolted connections at the assembly stage on an example of the engine cylinder head-block connection. The physical model of the connection was introduced as a combination of three subsystems: the set of bolts, the joined element and the contact layer between the joined element and the rigid support. The finite element method (FEM) was used for the modeling. Bolts were replaced with hybrid elements. The joined element was modeled with spatial finite elements. The Winkler model of the contact layer has been taken into consideration. The truth of the theorem has been examined, according to which non-linearity of the contact layer has a negligible impact on the final values of the bolt forces in the case of sequential preloading of the multi-bolted connection. The results of the calculations of a selected multi-bolted connection have been compared with the experimental results.
... Both components are joined by fastening with bolts under specific torques using a gasket in between to seal the joint. The gasket is designed with various holes to allow the independent and transversal flow of coolant, oil, and combustion gases from the mono-block to the cylinder head and vice versa through individual vessels connected by the joint [17]. So, the gasket helps to seal the joint of such vessels permitting each fluid to flow independently, as depicted in the schematic representation in Fig. 1. ...
... The profiles obtained from both single and assembly specimens after the testing are shown in Figs. [16][17][18]. The volume of the whole regions of corrosion localized next to the gasket were considered as crevice corrosion sites, so all of them were estimated for each assembly and then compared. ...
A test to evaluate crevice corrosion in joints of mechanical components sealed with composite structure gaskets in corrosive environments is presented. The crevice corrosion produced in joints comprising the cylinder head, gasket and mono-block was aimed as a study case to illustrate the test. It is based on polarization resistance and potentiodynamic polarization measurements obtaining localized and measurable crevice corrosion on small specimens in a short time. Corrosion rates, crevices volumes and potentiodynamic behavior of assembly specimens made of three different aluminum alloys extracted from actual cylinder heads and mono-blocks, and sections of cylinder head gasket were obtained and reported.
... Both the design and development of an automotive engine are complicated processes. To acquire the best performance and optimize the engine design in any operating condition, many analytical tools and experimental works are needed to find the optimum structure for the engine design (Kamal, Rahman, & Sani, 2013a;Lee, Chiang, Chen, & Chen, 2005;Rahman, Ariffin, Rejab, Kadirgama, & Noor, 2009). In the automotive engine, the cylinder head structure is the most important component affecting the performance of a car and one of the heavily loaded combustion chamber components (Zhao, Lai, & Harrington, 1999). ...
... In the automotive engine, the cylinder head structure is the most important component affecting the performance of a car and one of the heavily loaded combustion chamber components (Zhao, Lai, & Harrington, 1999). All these components require careful attention especially during the assembly design in order to avoid any failed structure at engine operations (Ali, Mustapa, Ghazali, Sujitno, & Ridha, 2013;Kamal, Rahman, & Rahman, 2012;Lee et al., 2005). The cylinder head of a direct injection engine is highly influenced by the geometry of the combustion chamber injector location. ...
In this work, the design and simulation of a cylinder head with compressed natural gas direct injection (CNGDI) is studied based on finite element analysis. The analysis was carried out to simulate the stress and displacement for the cylinder head at various engine speeds in the range of between 1000 and 5400 rpm. The design is developed using CATIA V5, and simulated using MSC Nastran, then pre-and post-processed by MSC Patran. Based on the simulation results, an improved design for the CNGDI cylinder head was achieved. The stress and displacement analysis highlighted several areas of interest, and the maximum stress for the modified model of 56.16 MPa was found not to exceed the allowable compressive yield strength of the material used (aluminum alloy A356-T6), of 172 MPa. The maximum displacement for the modified model, which was 0.00972 mm, was below the lowest displacement limit of 0.032 mm. For the modified model, the strength was improved by about 1.72%, and the displacement decreased by about 3.55% compared to the original model. Thus, the result can be used to assess the quality of the design, where no yielding and structural failure occurred in the firing load case, as having satisfied the requirement.
... The bolt pretightening forces were predicted so as to realize the uniform distribution. In view of the complex working condition of the gasoline engine, Lee et al. (2005) studied the stress of the cylinder head and the contact force distribution on the gasket. They proved that the bolt pretightening forces and gasket design are the key factors to improve the sealing performance. ...
To date, sealing structures have been widely used in aerospace vehicles. This paper presents a normalized and systematic procedure realizing lightweight design for a square bolt-flange sealing structure of a rocket engine. To measure the sealing behavior, the contact force on the sealing interface is obtained by a nonlinear analysis of node-to-node contact. The topology optimization is established to achieve sufficient contact forces in the sealing area by acquiring the Kreisselmeier-Steinhauser (KS) function to condense multiple contact force constraints into a global sealing constraint. A three-field projection scheme is also adopted to obtain a clear result and a semi-analytical perturbation scheme is proposed to realize the sensitivity calculation. Then, the square flange cover is optimized by the proposed optimization framework and a lightweight design with a clear load-carrying path is obtained. The optimized design is reconstructed and further optimized in detail. Compared with several traditional designs, it shows better leakproofness under inner liquid pressure, which can be directly fabricated by additive manufacturing and used in the rocket engine. The optimization procedure is proved effective and practical in designing sealing structures for aerospace vehicles.
... The failure analysis of a cylinder head made of aluminum concluded that the crack was caused by the appearance of high prestressing [11]. In papers [12][13][14] the locations with the highest stress values on the cylinder heads were determined by numerical analysis. ...
Failures of aircraft piston engine components are a common occurrence in practice. During operation, cylinder heads are components that are exposed to multiaxial thermomechanical loads leading to fatigue. Therefore, predicting the lifetime of the cylinder heads exposed to such loads is one of the most important tasks to ensure engine quality, durability and safety. This paper is the continuation of a comprehensive research of the Lycoming IO-360-B1F aircraft engine cylinder head failure. The failure of this type has already occurred during flight and about 50 failures like this have been registered from around the world, some of them with a fatal outcome and therefore require detailed research. This research includes the numerical stress and fatigue analysis of the cylinder assembly exposed to high cycle mechanical and thermal loads that failed due to a crack appearance on the cylinder head. A 3D cylinder assembly model was created. The locations with the highest stress values, both mechanical and thermal, were determined using numerical analysis. Also, the lifetime of the cylinder assembly has been determined, i.e. an integrity assessment has been carried out which will contribute to the consideration of the crack appearance problem. Defining the coupled thermomechanical load of the cylinder assembly in the numerical analysis gives special significance to this paper. The results obtained will serve to analyze the crack propagation in the cylinder head which is going to be the subject of further research.
... A full load and unload characteristic of the expanded graphite was introduced to numerical model. In a similar way a model of the gasket material was defined, among others, in Ref. [20]. ...
The paper presents the experimental as well as numerical research of a bolted flange joint with an elastic serrated gasket. Two constructions of a metal core were proposed. Their cross-section shapes were different in relation to the standard solution. Results of the experimental research showed that the elastic core provides a considerable increase of the joint tightness compared to the tightness of the joint sealed with a standard gasket. Next, numerical analysis was conducted whose aim was to determine contact pressure on the interfacing surface between the gasket and flange. It appeared that proper forming of the core cross-section provides quite regular distribution of contact pressure along the gasket width. The final part verified the numerical computation and explains the effect of the increased tightness of the joint with an elastic core.
... Kapgate et al. [5] analyzed deformation, contact pressures, slippage during preload and failure stresses as bolted joints are subjected to preload, shear and bending loads. Lee et al. [6] found that sealing efficiency of gasket depends on the prestressing force of the hold-down bolts, without the thermal stresses. Kumar et al. [7] investigated the structural analysis of a cylinder head under different loading conditions with the numerical simulation of finite element analysis. ...
A gasket is fitted between two or more mating flanges which fills the gap and acts as mechanical seal; it prevents leakage when flanges are in compression. In order to obtain perfect sealing and joint, proper selection of gasket thickness and gasket material is essential. In the majority of cases, mechanical seal is obtained by gasket when external forces are applied; this allows gasket material to flow into the irregularities between the flange surfaces; external forces can be applied by the bolt under load (bolt preload). The preload should be applied equally over the whole seating area to obtain a complete sealing. Hence, preload plays an important role and performance of gasket joint depends upon preload. In this study, finite element analysis of bolted gearbox flange joint has been carried out and numerical results have been compared by taking experimentally the obtained characteristics of the gaskets for various thicknesses. This study reveals that the gasket thickness plays a vital role in the seal performance of gearbox flange assembly. Hence, it is found that the gasket with 3 mm thickness showed a significant reduction in the deformation and stresses.
... Sayman, et al. [2] analyzed the load-carrying capacity of the single lap joint bonded by an adhesive found with experimental methods. Lee, et al. [3] showed that the sealing efficiency gasket depends on the pre-stressing force of the hold down bolts, excluding the thermal stresses. ...
Heavily loaded flanged joints should not only carry the mechanical loads that are imposed, but they should also provide a fluid seal. Historically, such heavily stressed flanges were sealed with thin paper composition gaskets so that when flange joint was operated at critical load then high compressive forces were induced within the joints. Over the use of gaskets in the flange, they get deformed and due to this torque capacity, they get reduced hence creating some gaps which are potential leak paths. In recent years, chemical gasketing (liquid “formed in place gaskets”), has begun to surface as a possible solution for these dual function flanges. Hence liquid sealants have been introduced in this flange. In coming days, anaerobic and silicone sealants will be introduced in industry, in contrast with solid gaskets which deteriorate gradually with the atmospheric moisture. Anaerobic and Silicone sealants are mostly used because they are ideally suited to small flange gaps curing them rapidly. This paper focuses on the study of gaskets and liquid sealants effects on gearbox flanges. This work has revealed that structural anaerobic sealants significantly reduced the deformation by 6.7μm, and it improved the structural shear strength and shear modules. This paper also investigates the numerical and experimental analysis of gearbox anaerobic sealant flange assembly and it determines the mode shape frequency.
... The cylinder head could also fail during operation due to thermal fatigue cracking especially in the water jacket cooling area because of narrow path between the valves and the exhaust valve seat [8], as shown in Figure 2. For its structural strength, the finite element analysis can be used to obtain the stress and strain profiles of the cylinder structure, which could be analysed further to ensure that the maximum stress does not exceed the allowable yield strength limit [9]. ...
Due to abundance of natural gas, the use of natural gas for automotive use, particularly for internal combustion engine (ICE), is more practical and cheaper than their future successors. Even though natural gas is a cleaner fuel than other fossil fuels and has a higher octane number and can lead to higher thermal efficiency, its low carbon number makes it less attractive as compared to gasoline and diesel. Based on its potential, an engine referred to as compressed natural gas direct injection engine (CNGDI) was designed, developed and tested to operate on compressed natural gas (CNG) as monofuel directly and centrally injected into the engine. Computational and experimental works have been performed to investigate the viability of the design. Computational fluid dynamics (CFD) simulations and experimental works with homogenous combustion showed that the results were in good agreement. From experimental works, it is found that combustion characteristics could be improved by using a stratified charge piston configuration with some drawback on performance. In terms of exhaust emissions, stratified configuration causes slight increase in the emission of CO, CO 2 and NO x , which highlight a need for further study on this issue.
... Even though automotive manufacturers implicitly conduct life-cycle planning and product design from a life-cycle perspective, specific methodologies have not been deployed [20,21] owing to the fact that design and development of an automotive engine involves complicated processes [22]. To acquire the best performance and optimise the engine design in any operating condition, many analytical tools and experimental works are needed to find the optimum structure for the engine design [23]. ...
Life-cycle thinking in the development of new products has led design engineers to rethink the way they design sustainable products. One of the most viable approaches is designing products for multiple life-cycles. For this purpose, a sustainable design tool that has a broader perspective in providing design guidelines to enhance end-of-life product recovery for multiple life-cycles is necessary. However, there are too many design requirements, some of which are conflicting. Designers are not supported by specific methodologies or tools to evaluate the weightage and importance of the design elements. Therefore, an extensive review of the design requirements of remanufacturable products was conducted in order to identify the design elements for multiple life-cycle products. A modified Analytical Hierarchy Process method was developed based on the design strategies in order to obtain the weightage that indicates the importance of each design element. The proposed approach is capable of refining and setting priorities in strategic decision-making during the design phase of a multiple life-cycle product. Verification of the strategic factors was based on an in-depth interview with an automobile engine remanufacturer. Based on the study, disassemblability and assemblability were found to be the two most important criteria in designing automobile engines for multiple lifecycles.
... The total numbers of the elements and nodes in the model are 601 736 and 690 912, respectively. The material properties of the components taken from literature [20] are utilized in this analysis. ...
In an automotive powertrain system, the cylinder liner is one of the most critical components which possesses the intricate structural configurations coupled with complex pattern of various operational loads. This paper attempts to develop a concrete and practical procedure for the optimization of cylinder liner distortion for achieving future requirements regarding exhaust emissions, fuel economy, and oil consumptions. First, numerical calculation based on finite element method (FEM) and computational fluid dynamics (CFD) is performed to capture the mechanism of cylinder liner distortion under actual engine operation conditions. Then, a spectrum analysis approach is developed to describe the distribution characteristic of operational loads (thermal and mechanical) around the circumference of a distorted cylinder bore profile; the FFT procedure provides an efficient way to implement this calculation. With this approach, a relationship between the dominant order of distortion and special operational load is obtained; the design features which are critically relative to cylinder liner distortion are also identified through spectrum analysis. After characterizing the variation tendency of each dominant order of distortion through parametric analysis, a new design scheme is established to implement the distortion optimization. Simulation results indicate that a much better solution is obtained by using the proposed scheme.
... In comparison to fossil diesel oil, biodiesel presents several advantages: first of all, it is a renewable energy source; second, the environmental impact in terms of CO2 is strongly attenuated by the amount of carbon dioxide absorbed by the plants during the growing process [5]; third, some emissions, such as soot, are generally lower than in fossil fuel, as reported in [6][7]. The main downside is the requirement of new fuel systems, complying with the specific features of biofuels; furthermore, many authors found an increase in nitrogen oxides (NOx) emissions running on biodiesel [8][9][10], even if sometimes no changes in NOx emissions where reported [11]. Finally, different studies report that the engine power output may be negatively affected by the presence of biodiesel because of its lower lower heating value [12][13][14], even if, in some cases, the power loss was lower than expected as reported, for example, in [15,16]. ...
This study emphasizes on the combustion of diesel engine using different biodiesel blends. Rapeseed biodiesel is an interesting option to address the problem of decreasing availability of conventional fossil fuels, as well as to reduce the CO2 emissions of internal combustion engines. The present paper describes an experimental campaign carried out on a current production 4-cylinder, 4-stroke naturally aspirated diesel engine, running on standard diesel fuel and on three different blends of rapeseed biodiesel (20%-50%-100%). Performance, emissions and in-cylinder pressure traces were measured at full load. It was found that the influence of rapeseed biodiesel in the fuel blend is not constant at each operating condition. However, as the biodiesel content increases, full load performance tends to drop, in particular brake specific fuel consumption (maximum worsening: +18%), while soot emission goes down. The maximum improvement observed in terms of soot concentration is 37.5%, at 1200 rpm. The combustion analysis revealed that the main differences among the fuels occur in the first phase of combustion: the burn rate is slower for biodiesel blends at low speeds, and faster at high.
... They used the commercial FE code to predict thermal and stress/strain results at various loading conditions and operating environments. The structural analyses of a cylinder head under engine operating conditions were performed in [15,16] using finite element simulation. It was reported that the capacity of gasket sealing was principally dependent on the pre-stressing of the bolts, which was the source of the maximum external loading on the inner structure of the cylinder head. ...
Simplified finite element model of spark ignition (SI) engine to analyze combustion heat transfer is presented. The 2D model is made up with main features of engine including combustion chamber, valves, manifold, cylinder body, piston head and cooling jacket, all projected at the cross section of the cylinder. The model was discretized with 2D thermal elements of global length 0.001. The fuel type is gasoline. Internal nodal temperature of cylinder body is defined as 2100°C to represent occurrence of gasoline combustion. The presence of cooling is modeled by assigning convection coefficient on cooling jacket. Material information and isotropic material properties are taken from published report. The transient heat transfer analysis is done for the instant of combustion. The model is validated by comparing the computed maximum temperature at the piston surface with the published result. The computed temperature gradient at the crucial parts are plotted and discussed. It has been found that the critical component likely suffered from thermal fatigue was the exhaust port near the cylinder head and the materials used to construct the engine parts strongly influenced the temperature distribution in the engine. The model is capable to analyze heat transfer in the engine reasonably and efficiently.
... Traditionally, optimization of engine components such as the cylinder head was based on constructing a detailed FE model and carrying out a series of different numerical simulations . A pioneering computational work dealing with the prediction of a distorted cylinder head was performed by Chyuan [3]. Lee et al. [4] further complemented the full threedimensional FE model, and applied the contact theory to evaluate the sealing efficiency of a 2.0 L cylinder head. Later, by integrating the finite element method (FEM) and computational fluid dynamics (CFD), Shojaefard et al. [5] explored a general methodology to simulate the interactions between structural mechanics, heat transfer, and fluid coolant within the cylinder head. ...
The engine cylinder head is one of the most critical components in an automotive powertrain system. Yet, it has the most complicated
mechanical structure coupled with a sophisticated combustion process. This study attempts to develop a concrete and practical
procedure for the optimal design of the engine cylinder head. First, a simplified topological model composed of beam, shell
and membrane elements is developed to simulate the real cylinder head. With this model, the finite element method can be easily
and economically employed to study the load-bearing mechanism of the cylinder head under actual engine operation conditions.
After characterizing the stress/strain behavior of all the key components through parametric analysis, a new optimization
criterion is developed based on Lagrange conditions. This criterion provides an opportunity to represent the ideal ‘balanced
point’ among the main design parameters of the cylinder head in terms of weight distribution of the key components. Finally,
the optimization of the cylinder head structure is implemented successfully based on these findings. Compared to the optimization
results from commercial software, the proposed approach is able to produce a much better solution in respect to both the convergence
speed and the final value of the objective function.
KeywordsEngine–Cylinder head–Optimal design–Topological model–Parametric structure characterization–Weight distribution criterion
The cylinder head is a vital component of an internal combustion engine (ICE), playing a critical role in the combustion process, sealing the combustion chamber, and facilitating efficient heat dissipation. With the increasing demand for higher performance, efficiency, and durability of engines, the design and analysis of cylinder heads have become paramount. Finite Element Analysis (FEA) has emerged as a powerful tool for assessing the structural integrity, thermal behavior, and performance of cylinder heads under various operating conditions.This abstract presents a comprehensive review of recent advancements in FEA studies focused on ICE cylinder heads. The analysis encompasses aspects such as static and dynamic structural integrity, thermal stress distribution, and fluid-structure interaction within the combustion chamber. Various loading conditions including thermal loads from combustion, mechanical loads from valve actuation, and pressure loads from combustion gases are considered in the simulations.
The primary goal of this book series is to promote research and developmental activities in mechanical engineering. It aims at promoting scientific information exchange among the academicians, researchers, developers, engineers, students, and practitioners working around the world. This book covers the chapters on Advances in Mechanical Engineering.
A multi-scale nonlinear procedure to analyze the stress in Nb 3 Sn superconducting accelerator magnets is presented to address one of the most challenging obstacles currently facing the successful development of high-field superconducting magnets—the issue of stress management. The study demonstrates that gasket materials (special nonlinear materials) are capable of modeling the complex nonlinear deformation behavior of insulation layers within the Nb 3 Sn coil block and that Hill materials (orthotropic materials utilizing the Hill yield criterion) are suitable to enable homogenization of the filamentary regions and the resin-impregnated Nb 3 Sn Rutherford cables. With the whole magnet under preload, cool-down, and Lorentz forces, the nonlinear behavior of the Nb 3 Sn coil was simulated, in three orthongonal axes, using the combined properties of the gasket materials (insulation layers) and Hill materials (resin-impreganted cable). The procedure makes very few assumptions with regard to material properties because it incorporates actual measured stress–strain curves in the analysis. The coil was simulated to the level of detail of the insulation layers and resin-impregnated cables. The computed compressive azimuthal stresses of the cables were used to assess stress-induced performance degradation. Through submodeling, the area-weighted average axial strains of the strands were computed and employed to evaluate the strain-induced performance degradation. The overall performance degradation of the Nb 3 Sn coil was thus obtained, and this information was subsequently used to guide the design of the overall magnet. Besides Nb 3 Sn magnets, this versatile procedure can also be employed in the design of LTS, HTS, and room temperature magnets or of any structures ultilizing composite materials; specifically, it can be used to manage the stress and strain of HTS fusion magnets.
Currently, the common-rail injection system is composed from a high-pressure pump, injectors, an electronic control unit and a common rail. Over time, the common-rail system has been simplified and optimized, but it remains that the high-pressure pump can still be affected by distortion which occurs during the pump assembly process and in turn has an effect in mounting the pump to the engine. The main assemblies of the diesel pump are the front plate, housing, driveshaft and hydraulic head. Our paper presents a solution for minimizing the distortion and also any external leaks that may occur due to a change in design of the sealing gasket between the body and front plate. This modification realizes the connection interface with the engine block and facilitates the pump mounting. The tests analysis is performed on high pressure pumps to determine where and when the distortion occurs.
Background/Objective: Cylinder liners are very important part of an automobile engine and working of the liner
directly affects the engine performance. Conventional cylinder liners are being replaced with high temperature composite
materials. The present work is to identify the performance of cylinder liners under combined mechanical and thermal load
in terms of radial, longitudinal and hoop stresses by selecting different high temperature composite materials. Methods/
Findings: Different high temperature composite materials such as Carbon/Polyimide, Woven Carbon/Phenolic, Woven
Graphite Phenolic, Carbon/Carbon composite, Boron/Aluminum, Silicon/Carbide composite cylinder liners are analyzed
by applying pressure and thermal load. The variation in the radial stresses (σr
), longitudinal stresses (σl
) and hoop stresses
(σθ
) are identified for selected materials. Thermo mechanical strains in radial, axial and circumferential directions are
also identified. The analysis is performed by Finite element based software ANSYS. Solid 8node 183 elements are selected
to perform the analysis. The Fe models are validated with the analytical equations. Application: Among all the materials
considered in the analysis, Carbon/Carbon composite performance is good under considered loading and boundary
conditions. Compared to all the stresses, the severity of axial stresses is more than radial and hoop stresses. The present
work is used for the effective design of cylinder liners with high temperature composite materials.
The cylinder head gasket (CHG) joint is the most critical sealing joint for IC engine performance. Cylinder head bolt preload application should be stoichiometric. Excess cylinder head bolt pre-tension develops more stress and further leads to bore deformation. Insufficient cylinder head bolt pre-tension leads to gasket leakage. It is challenging to achieve uniform pressure distribution because of variation in stiffness of block and head. But the minimum pressure must be ensured for leak-proof joint. In this article, gasket pressure distribution around the cylinder bore is estimated by non-linear Finite Element Analysis (FEA) and compared with Fuji Film results. Bore deformations, due to spiral and cross patterns, are determined and compared. Piston ring conformability is estimated in terms of percentage sealing of the ring to the liner. Effects of bolt tightening strategies are investigated for engine gasket sealing parameter, bore deformation and piston ring conformability.
Combustion ignition study is important due to the combustion process becoming more lean and efficient. The location of the ignition was critical to ensure that the spark energy supply during the ignition process can successfully ignite the mixture of air and fuel. The population of spark-ignition vehicles in urban areas is very high and is increasing rapidly due to their convenience for short distance transportation. These vehicles are major sources of urban air pollution compared to vehicles with diesel engines. Catalytic converters are used to control their emissions but they attain their maximum conversion rates of about 80%–90% under optimum operating conditions and are not effective during cold start conditions. Other combustion is direct ignition. The full DI resulted in a 20% higher performance than the early injection timing for low engine speeds up to 2750 rpm. Besides, Homogeneous charge compression ignition (HCCI) engines employ a relatively new mode of combustion technology, in which auto-ignition occurs when the lean mixture of air and fuel reaches its chemical activation energy. It is a combustion concept that offers simultaneous reductions in both NOx and soot emissions from internal combustion engines. A wide range of fuels can be used in this engine.
Finite element analysis was carried out to evaluate the distribution of stress along the fillet on an upper deck of cylinder block during the operation of diesel engine. The dynamic stress by cyclic combustion was analyzed taking into account the equilibrium of force acting in the main body assembly and cylinder head bolts in addition to their relative displacement condition. Preliminary analysis was firstly carried out to evaluate the stiffness ratio of cylinder head bolt and the main body assembly. The ratio was used for the main stress analysis of cylinder block. The main analysis was conducted for test and prototype engines. Their specifications are almost same except for the tightening position of cylinder head bolt. The following results were obtained. The distribution of stress during operation was not axisymmetrically but varied depending on the relative location against the outline of cylinder block and cooling water jackets. The results also agreed with the measured stress values. The amplitude and mean of stress obtained by the present analysis plotted on the fatigue limit diagram corresponds to the presence or absence of crack initiation along the fillet of test and prototype engines.
To research sealing performance of the cylinder head gasket in an automotive engine, the numerical calculation for the gasket under pre-tightened condition was performed based on the large-scale FEM software ABAQUS. By establishing 3D model, discretization of structure and setting boundary conditions, the data of contact pressure distribution and Von-Mises stress on the gasket were obtained. The results reveal that the contact pressure is mainly distributed on the embossments and the sealing effect is mainly dependent on the head bolt pre-tightening force and the embossment structure. The finite element analysis (FEA) results confirm that the cylinder head gasket design must match the adjacent part and component conditions. And the established model is proved to be able to satisfy requirements of the cylinder head gasket design.
Proper sealing of an engine is very important parameter in an engine design. Even small amount of gas leakage from the engine can affect the overall performance of the engine during operation. There are two important factors in enhancing the efficiency of the sealing of the gasket are right tightening torque of bolts & gasket design. In this study, both the distribution of the contact pressure on the gasket, and the stresses of the cylinder head at different loading conditions, such as cold assembly, hot assembly, cold start, and hot firing, is simulated by commercial tool, based on the finite element method (FEM). The results shows that the efficiency of the sealing of the cylinder head gasket depends on the tightening torque of the hold-down bolts, without taking into consideration any thermal load resulting from the temperature distribution in the cylinder head. Study also shows that, the location of maximum contact pressure on the gasket is changed when the thermal loading is taken into account.
Head gasket is the name given to the mechanical seal between cylinder block and cylinder head. It is expected to seal gases from the combustion chamber, the coolant and the lubricant from one another during the varying ranges of temperature and pressure conditions during engine running caused by varying engine speeds and loading. The stopper area is the most important part of the head gasket. From the literature, it was understood that approximately 60-80% of head bolt stresses act on stopper area. This makes the designing of stopper area based on head bolt stresses critical. This paper aims at understanding the structural behavior of various proposed gasket stopper designs and thereby propose a new design, using the numerical simulation used by Chang-Chun Lee et al, 2005 as this design’s validation technique.
Simplified finite element model of spark ignition (SI) engine to analyse combustion heat transfer is presented. The model was discredited with 3D thermal elements of global length 5 mm. The fuel type is petrol. Internal nodal temperature of cylinder body is defined as 21000C to represent occurrence of gasoline combustion. Material information and isotropic material properties are taken from published report. The heat transfer analysis is done for the instant of combustion. The model is validated by comparing the computed maximum temperature at the piston surface with the published result. The computed temperature gradient at the crucial parts are plotted and discussed. It has been found that the critical top surface suffered from thermal and the materials used to construct the engine parts strongly influenced the temperature distribution in the engine. The model is capable to analyze heat transfer in the engine reasonably and efficiently.
Gasketed flange joints are usually subjected to internal pressure at high temperature. The most important requirement of flange joint is to provide leak-free joint under operating condition. In the present study, temperature-dependent nonlinear gasket properties of spiral-wound gasket at elevated temperatures are obtained experimentally and included in the analysis. The relaxation of gasket contact stress in both single and twin-gasketed joints at elevated temperatures is compared. It is observed that the ability to withstand internal pressure decreases with increase in temperature in both single and twin-gasketed flange joints. But, the twin-gasketed flange joint is found to withstand higher internal pressure than single-gasketed joint at a given bolt preload and temperature. The influence of gasket seating surface rotation on the distribution of gasket radial contact stress at elevated temperature is studied. The effect of elevated temperature on flange stresses of twin-gasketed joint is also examined.
Recently, product manufacturers of mobile phone have to meet to high demands that allow their products endure variable bad environments exposed throughout the customers’ use. Especially, mobile phones need to resist to high humidity and general waterproofing that is prevalent in everyday usage. However, most previous studies related to seal material or methods for sealing assembly have been focused on heavy industry or automotive industry. In this paper, the aim is to predict waterproof possibility of mobile phone by using finite element analysis in design step. The criteria of waterproof condition for mobile phones was based on IEC60529 IPX-7 level[1]. This paper studied behavior characteristics and properties of the specialized rubber material for sealing the mobile phone housing. Constitutive equation for specialized seal rubber material was applied to the 3rd order Ogden function. Then, the correlation with test and finite element model was studied. Using the correlated finite element model for specialized seal rubber, evaluated behavior characteristics for seal rubber 2D shape and studied waterproof possibility analysis 3D model of mobile phone.
The proposed suggestion is expected to predict waterproof possibility for mobile phone efficiently. Evaluation method of 2D finite element model will be useful for decision design specification of seal rubber shape at preceding design step. And evaluation method of 3D finite element model will predict waterproof possibility before tooling the mold and will save the costs at development step in industry.
The research focuses on the solutions to avoid overheating the intake and exhaust valves due to engine overload. Subaru EJ25 engines are currently mounted in passenger cars such as Subaru Impreza but the author's innovative idea is to use them in small passenger airplanes. The paper describes the coupled thermo -mechanical load model of a supercharged Subaru EJ25 engine. The engine piston was tested thermally and mechanically, and the intake and exhaust valves only thermally. The calculations were done using the finite element method (FEM) in ABAQUS 6.10. Parts where divided into Hex and Tet mesh elements, depending of their geometry. The models used in the simulation were previously created using CATIA v5. Because there were only separate parts, the authors used only Part Module. The process of 3D scanning based on the method of reverse engineering was for fine mapping the surface of the examined parts, e.g. a piston. The boundary conditions and material properties are based on the literature and the information provided by the companies that sell spare parts for this engine. The simulations were done for varied heating times and mechanical load (25, 50, 100, 250, 400 seconds).
The motivation of this paper is to develop a straightforward approach to provide an optimal solution to cylinder head design. In this research, a topological plot is first defined to represent the load bearing topology of the cylinder head. A simplified model enabling a designer to clearly understand the global matching relationship between the key components of a cylinder head is then identified from the topological plot. After characterizing the stress/strain behavior through parametric analysis, an interesting phenomenon associated with stress convergence in the cylinder head is observed. A concise mathematical explanation for this phenomenon is then derived from the well-known Kuhn–Tucker conditions, leading to a novel optimization criterion for cylinder head design. In this criterion, the optimal solution is described as an ideal “balanced point” among the main design parameters in terms of weight distribution of the key components. The benefits and advantages of the proposed method are finally confirmed by a concrete design case.
The YZ4105 diesel engine cylinder liner was analyzed by using of finite element analysis software ANSYS. Taking into account the basis contacts of various components, this paper calculated the stress and displacement distribution of cylinder liner under the function of heat - coupled structure, and provided a reference for improving a design.
This paper presents a thermal network model for the simulation of the transient response of diesel engines. The model was adjusted by using experimental data from a completely instrumented engine run under steady-state and transient conditions. Comparisons between measured and predicted material temperatures over a wide range of engine running conditions show a mean error of 7°C. The model was then used to predict the thermal behavior of a different engine. Model results were checked against oil and coolant temperatures measured during engine warm-up at constant speed and load, and on a New European Driving Cycle. Results show that the model predicts these temperatures with a maximum error of 3°C.
An engine cylinder head-block joint is a gasketed, bolted joint. Assessment of sealing performance and fatigue durability
of the joint during engine development relies entirely on the engine dynamometer test because the rig test cannot mimic the
engine run condition and finite element analysis employs gasket and bolt models that are too simple to provide the stress
data for fatigue assessment. This paper introduces finite element-based assessment of the gasket and the bolt and a model
that improves the analysis accuracy without increasing computation time. Experimental data for the deformation of joint members
under thermo-mehanical load are presented to demonstrate the accuracy of the model.
Key WordsEngine cylinder head-block joint-Multi-layer steel gasket-Bolt-Finite element analysis-Sealing-Fatigue
A four-cylinder diesel engine model is established using Pro/Engineer 3D modeling software. The model is loaded by ANSYS software. Grids meshes are imposed to the model with contact-settings and boundary conditions. Finite element analysis is performed on the contact-state of the diesel engine body. According to the minimum-zone principle for the flatness error analysis, Particle Swarm Optimization algorithm (PSO) is applied, and the mathematical model and method of the engine body top-surface-flatness error analysis is established. Based on the established method, the engine body top-surface-flatness errors can be obtained under the maximum preload working conditions, providing an accurate and effective way for further improvement of the engine tightness and body design.
The analysis of gasketted flanges is now becoming an essential technique to design pressure vessels or piping, because the design code is being modified. On the other hand, the gasket has an extreme nonlinearity which causes the analysis to be very difficult, especially using linear material properties. A finite element analysis program other than ANSYS has the element library for gasket element, but ANSYS does not have it yet. The authors developed a method to model this nonlinear gasket by using the elements available in ANSYS Rel. 5.5 for 2-dimensional axisymmetric analysis and those in Rel. 5.6 for 3-dimensional analysis. In this paper, the concept and the procedure of the modeling is introduced. The data input is possible using a template, without using any other ANSYS commands. The whole analysis execution is controlled by APDL. The used elements are 8-noded axisymmetric quad elements, contact (gap) elements and a bar element for 2-D. In the same manner, 8-noded brick elements, contact (gap) elements and a new pre-tension elements are used for 3-D.
The finite element method is used as the numerical technique to obtain the contact stresses between two or more elastic bodies with friction on the contact surfaces. In this method, the normal stress and shearing stress on the contact surface which are induced by their contact are represented by the reaction forces at the nodes on the contact surfaces. Numerical results for two rectangular plates and two cylindrical columns having different sizes and Young's moduli which are compressed into one another are obtained. Contact pressure along the contact surface of rectangular plates without friction is in good agreement with the exact solution for semi-infinite plate, except near the end of the contact surface. Also the influences of friction on the contact stresses are discussed.
A modified finite element method for solving problems of elastic bodies in contact is described. The method is general and could be extended to solve other than elastic problems. The sample results agree well with corresponding exact solutions.
Modeling bolts for three-dimensional finite element applications have, and still continue to raise questions. The limitations on model size sometimes make modeling of solid bolts impractical. Therefore, many analysts choose other methods to model bolts. Line elements with coupled nodes and line elements with spider beams are a couple of alternative approaches. This paper looks at a few methods for modeling pretension bolted joints using the finite element method (ANSYS 5.7). Pretension is modeled using ANSYS pretension elements (PRETS179) which can be used on solid or line element types. Surface-to- surface contact elements are used to account for varying contact distribution along flanges. Bolt head and nut behavior is modeled by, coupled nodes, beam elements, rigid body elements (RBE3), or solids. Bolt stud is modeled by solid elements, beam elements, pipe elements, or link elements. The choice of line elements versus solid elements is determined by the degree of complexity sought. The pros and cons of different simulations are also discussed.
Thermal contact conductance should be high in such applications as
nuclear reactors, gas tubines, aircraft structural joints, etc.; when
mechanically strong insulation is required, by contrast, as in the
storage of cryogenic liquids, contact resistance must be as high as
possible. Attention is presently given to the results obtained since
1970 by theoretical and experimental studies of conduction through
contact spots and through interstitial materials. Special problems that
are introduced by the geometry of contact, load cycling, and heat flux,
are also discussed. Recommendations are made concerning the most
fruitful directions for future investigation.
Contact-impact algorithms, which are sometimes called slideline algorithms, are a computationally time-consuming part of many explicit simulations of non-linear problems because they involve many branches, so they are not amenable to vectorization, which is essential for speed on supercomputers. The pinball algorithm is a simplified slideline algorithm which is readily vectorized. Its major idea is to embed pinballs in surface elements and to enforce the impenetrability condition only to pinballs. It can be implemented in either a Lagrange multiplier or penalty method. It is shown that, in any Lagrange multiplier method, no iterations are needed to define the contact surface. Examples of solutions and running times are given.
A technique of differential displacements is presented whereby problems involving elastic contact are solved by the finite element method. The technique is applied to axisymmetric situations in which statically indeterminate conditions occur and is shown to provide a means for resolving these conditions in terms of contact stresses. Three typical engineering problems are analysed to demonstrate the technique in cases where body forces, thermal gradients and external applied forces are acting.
In the present paper, a new twin-cam 16-valve cylinder head and block structure accompanied with several important sub-components under "ring load and assembly loads has been investigated using the "nite element method. The "nite element analysis was executed using a commercial "nite element analysis software package, MSC/NASTRAN (trademark of MacNeal-Schwendler Corporation) and the "nite element modeling and pre}post processing was carried out using a popular computer-aided engineering tool, I-DEAS (trademark of Structural Dynamics Corporation). The physical behavior of the upstand design of gasket bead and liner, the sti!ness distribution of cylinder head, the preload of cylinder head bolts, the residual insertion loads of valve guides and valve seats, and "ring pressure have been thoroughly discussed. Meanwhile, the sealing and structural response analyses under assembly and "ring load cases highlighted several areas of interest. Suggestions obtained from this project have been forwarded to designer successfully, for incorporation of adjustment, and to other proper areas for design evaluation. 2000 Elsevier Science B.V. All rights reserved.
Frictional contact problem formulations have been extensively studied in the literature, both from a rigorous mathematical
viewpoint and more recently in the context of finite element analysis. The former primarily dealt with variational inequalities and existence and uniqueness issues using simple problems while the later employed variational equalities with numerical analysis tools to solve large-scale engineering problems. These formulations make use of the standard as well as nonsmooth optimization techniques. In this paper both the variational inequality and the variational equality formulations are reviewed and some example problems
are solved to illustrate them. Usage of standard as well as nonsmooth optimization techniques is explained. Despite extensive
research in the fields of mathematics and engineering, frictional contact remains as one of the most challenging problems
due to the difficulties involved in its formulation and solution procedures. So far, variational inequality formulation for
frictionless contact problems has been established firmly. This is due to the fact that equivalent standard optimization problems
can be associated with these inequalities. However, for general frictional contact problems this formulation runs into difficulties due to lack of equivalent optimization problem (more precisely, lack of a genuine
minimization functional such as the total potential energy) which has restricted its usage to solve large-scale problems.
Variational equality approach on the other hand has been quite successful to solve large-scale frictional contact problems,
but it relies heavily on numerical schemes (such as Newton-Raphson method) and user defined numerical parameters. A review
of elastostatic frictional contact problems employing variational inequality and equality formulations is provided. Computational procedures are studied and some insights are provided for their numerical aspects. The need for an alternate frictional contact problem
formulation that can alleviate the drawbacks in current variational inequality and equality formulations is discussed.
A framework is presented within which the method of augmented Lagrangians is readily applied to problems involving contact with friction. This method, which has enjoyed considerable success in the treatment of constrained minimization problems, has been previously applied to problems involving incompressible flow, incompressible elasticity of solids and even frictionless contact. An additional challenge to the method is provided by frictional contact problems governed by a Coulomb law, due to the special form taken by the frictional constraint. This paper describes a new extension of the augmented Lagrangian technique to frictional problems which is well-suited to finite element implementation. The proposed treatment inherits the traditional advantages of augmented Lagrangian techniques over penalty methods; namely, decreased ill-conditioning of governing equations, and essentially exact satisfaction of constraints with finite penalties. A set of numerical examples is presented in which the utility of the method is demonstrated even in the presence of finite deformations and inelasticity.
A two-dimensional (axisymmetric) transient heat conduction in components computer program (HCC) was successfully developed for predicting engine combustion chamber wall temperatures. The alternating direction explicit (ADE) Saul'yev method, an explicit, unconditionally stable finite difference method, was used in the code. Special treatments for the head gasket and the piston-liner air gap, the piston movement, and a grid transformation for describing the realistic piston bowl shape were designed and utilized. The results were compared with a finite element method and were verified to be accurate for simplified test problems. In addition, the method was applied to realistic problems of heat transfer in an Isuzu engine and a Caterpillar diesel engine, and gave good agreement with available experimental measurements.
Design and analysis of temperature distribution for 2.0 L cylinder head in engine operation
- C C Lee
- K N Chiang
- W K Chen
- R S Chen
C.C. Lee, K.N. Chiang, W.K. Chen, R.S. Chen, Design and analysis of temperature distribution for 2.0 L cylinder head in engine operation, in: The 20th National Conference on Mechanical Engineering, CSME, Taipei, Taiwan, 2003.
Modeling diesel engine cylinder head gaskets using the gasket material option of the SOLID185 element
- R Jonathan
R. Jonathan, Modeling diesel engine cylinder head gaskets using the gasket material option of the SOLID185 element, ANSYS User’s Conference, 2002.
Contact heat transfer—the last decade
- Medhusudana
Design and analysis of temperature distribution for 2.0L cylinder head in engine operation
- Lee