Structural Analysis of the Aluminum Cylinder Head for a High-Speed Diesel Engine (original) (raw)
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Structural Stress Analysis of an Engine Cylinder Head
Acta Polytechnica, 2005
This paper deals with a structural stress analysis of the cylinder head assembly of the C/28 series engine. A detailed FE model was created for this purpose. The FE model consists of the main parts of the cylinder head assembly, and it includes a description of the thermal and mechanical loads and the contact interaction between their parts. The model considers the temperature dependency of the heat transfer coefficient on wall temperature in cooling passages. The paper presents a comparison of computed and measured temperature. The analysis was carried out using the FE program ABAQUS.
‘Finite element analysis of a crankshaft of a diesel engine’
This research was a part of the project aimed at the increase in power of the direct injection turbocharged twelve-cylinder V-type diesel engine. Crankshaft of a high power high speed diesel engine is subjected to complex loading conditions and undergoes high cyclic loads of the order of 10 7 to 10 8 cycles. Therefore, durability of this component is of critical importance. Strength analysis was based on the assessment of factor of safety (FOS) of the engine augmented by brake mean effective pressure (bmep) and/or engine speed. In the first part of the study, mechanical loads due to gas pressure and inertia forces were obtained from engine cycle simulation. Relationships for displacement, velocity and acceleration of an articulated connecting rod piston as a function of engine geometry and crank angle were derived. In the second part, the range of bmep and engine speed was determined over which engine performance is satisfactory on the basis of fatigue. It was shown that with limitations imposed (unchanged design and material of the crankshaft) the crankshaft of the given engine can withstand increase in power up to 15%. It was recommended, that required increase in engine power should be realized by the increase in bmep, since the increase in engine speed would deteriorate combustion efficiency. Finite Element Analysis was used to verify stresses calculations. New features of procedure used and relationships obtained in this research apply to strength analysis of other types of internal combustion engines.
Failure analysis of a diesel engine cylinder head based on finite element method
Engineering Failure Analysis, 2013
Macro fatigue cracks are expected to occur in valve bridges of cylinder head when engine is operating in normal working condition. In order to determine the causes of these failures, stress analysis is carried out using finite element method with a concern of temperature dependency of material properties. Mechanical and thermal properties of material tested at high temperatures are applied to the finite element analysis. Furthermore, temperatures of the cylinder head in actual working condition are measured to validate the simulation results of finite element analysis. After that, stress computation is performed and the regions of stress concentration on the flame deck surface are obtained. The analysis results of stress show that the regions of stress concentration are in agreement with the actual failure regions of the cylinder head. When analyzing the failures on the flame deck surface of a cylinder head by evaluating stress concentration, temperature's effect on mechanical strength of material should not be ignored. The methodology of failure analysis proposed in this paper is time-saving and also relatively accurate and predictive in actual engineering practice.
The finite element analysis of the thermal stress distribution of a piston head
Computer aided engineering (CAE) tools allow engineers to design product and to simulate these designs for residual stress, structural response, thermal effects, pre-processing and post processing fatigue on the automotive component. The main purpose of the preliminary analyses presented in the paper was to compare the behavior of the combustion engine piston made of aluminum alloys. The paper describes the mesh optimization with using finite element analysis technique to predict the higher stress and critical region on the component. As initial condition we considered a temperature on the head piston of 330°C and a total pressure of 5 MPa. There were studied two cases, a piston head and a piston, pin and connecting rod.
Analysis of fatigue cracks of cylinder heads in diesel engines
Journal of Theoretical and Applied Mechanics, 2016
Loading conditions and complex geometry have led cylinder heads to become the most challenging parts of diesel engines. One of the most important durability problems in diesel engines is due to cracks in the valves bridge area. The purpose of this study is thermo-mechanical analysis of cylinder heads of diesel engines using a two-layer viscoplasticity model. The results of the thermo-mechanical analysis indicate that the maximum temperature and stress occurr in the valves bridge. The results of the finite element analysis correspond with the experimental tests carried out by researchers, and illustrate cracks in cylinder heads in this region. The results of the thermo-mechanical analysis show that when the engine is running, the stress in the region is compressive, caused by thermal loading and combustion pressure. When the engine is shut off, the compressive stress turns into tensile stress because of assembly loads. The valves bridge is under cyclic tensile and compressive stress state and thus is subject to low cycle fatigue. After several cycles fatigue cracks will appear in this region. The lifetime of this part can be determined through finite element analysis instead of experimental tests. The viscous strain is greater than the plastic strain which is not negligible.
1999
A combined experimental and analytical approach was followed in this work to study stress distributions and causes of failure in diesel cylinder heads under steadystate and transient operation. Experimental studies were conducted first to measure temperatures, heat fluxes and stresses under a series of steady-state operating conditions. Furthermore, by placing high temperature strain gages within the thermal penetration depth of the cylinder head, the effect of thermal shock loading under rapid transients was studied. A comparison of our steady-state and transient measurements suggests that the steadystate temperature gradients and the level of temperatures are the primary causes of thermal fatigue in cast-iron cylinder heads. Subsequently, a finite element analysis was conducted to predict the detailed steady-state temperature and stress distributions within the cylinder head. A comparison of the predicted steady-state temperatures and stresses compared well with our measurements. Furthermore, the predicted location of the crack initiation point correlated well with experimental observations. This suggests that a validated steady-state FEM stress analysis can play a very effective role in the rapid prototyping of cast-iron cylinder heads.
Design and Analysis of Crankshaft of Four Cylinder Diesel Engine for Heavy Vehicle
Crankshaft is an important part of in an engine assembly. Crankshaft consists of two web sections and one crankpin. Crankshaft converts the reciprocating motion of the piston to a rotary motion with a four bar link mechanism. This paper is related to design and finite element analysis of crankshaft of 4 cylinder diesel engine of heavy vehicle like truck. Engine has capacity of 3785.1cc. The finite element analysis in ANSYS software by using five materials based on their composition viz. FG260, FG300, EN8, EN24 and Aluminum Alloy material. The parameter like von misses stress, deformation; maximum principal stress were obtained from analysis software. The results of Finite element indicate that the Aluminum alloy material can be best suitable material among all.
Heat Transfer Analysis of a Diesel Engine Head
Acta Polytechnica, 2003
This paper documents the research carried out at the Josef Božek Research Center of Engine and Automotive Engineering dealing with extended numerical stress/deformation analyses of engines parts loaded by heat and mechanical forces. It contains a detailed description of a C/28 series diesel engine head FE model and a discussion of heat transfer analysis tunning and results. The head model consisting of several parts allows a description of contact interaction in both thermal and mechanical analysis.
DESIGN AND ANALYSIS OF A HEAVY-DUTY DIESEL ENGINE PISTON
The main objective of this project is to study the characteristics of different alloys such as Steel, Aluminum and Cast Iron and to the design and analyze the stress distribution of the piston with a suitable material above the actual engine condition for a heavy duty diesel engine. In this paper, thermal analysis and mechanical analysis is done. The parameters used for the analysis are operating gas pressure, temperature and material properties of the piston. In I.C. Engine, a piston is most complex and important part therefore for the smooth running of the vehicle; piston should be in proper working condition. Piston fails mainly due to mechanical stresses and thermal stresses. Analysis of the piston is done with boundary conditions, which includes pressure on the piston head during working condition and uneven temperature distribution from piston head to skirt. The analysis predicts that due to temperature whether the top surface of the piston may be damaged or broken during the operating conditions and also to provide sufficient cooling conditions. The theoretical design calculations are made and the CAD model is created using CREO software. CAD model is then imported into the ABAQUS software for the analysis of stress distribution.