Cylinder Head Model Research Articles

Effects analysis of thermo-mechanical loads on classified damage characteristics with the equivalent cylinder head model

As a vulnerable part of diesel engine, cylinder head is periodically subjected to the thermo-mechanical coupling loads. While due to the restriction of complex structures and working conditions, it makes the damage mechanism of thermo-mechanical coupling still unclear. In this research, thermo-mechanical responses are predicted successfully by load spectrums and the Sehitoglu theory. Then the effects of working loads on classified damage characteristics are analyzed with the equivalent cylinder head model. The results show that the deviations of temperature and stress are, respectively, within 10°C and 30 MPa, and it verifies the effectiveness of simulated component. Operating speed takes the greatest effect on the thermo-mechanical characteristics, and bolt force and gas pressure are negatively correlated with the responses of stress and strain. Fatigue life and damage are determined by the values of working loads. The effect of temperature load is the most dominant, MechDam and OxidDam increase substantially when operating speed exceeds 3500 r/min. The research will provide a theoretical reference for engineering design and optimization of cylinder head.

Structural and Thermal Analysis on Cylinder Head of VCR Diesel Engine Using ANSYS

The present work is to study the structural and thermal characteristics of cylinder head of Variable Compression Ratio (VCR) Diesel engine under different loads. The geometrical model of cylinder head is prepared using CATIA. The experiments were carried out at compression ratios of 16.5, 17.5 and 18.5. The results of stress-strain developments, heat flux and temperature variations at different loading conditions were simulated using ANSYS. From the results of analysis, the minimum values of critical stresses, heat flux and maximum factor of safety are obtained at 16.5 compression ratio.

A Video-Based Facial Motion Tracking and Expression Recognition System

We proposed a facial motion tracking and expression recognition system based on video data. By a 3D deformable facial model, the online statistical model (OSM) and cylinder head model (CHM) were combined to track 3D facial motion in the framework of particle filtering. For facial expression recognition, a fast and efficient algorithm and a robust and precise algorithm were developed. With the first, facial animation and facial expression were retrieved sequentially. After that facial animation was obtained, facial expression was recognized by static facial expression knowledge learned from anatomical analysis. With the second, facial animation and facial expression were simultaneously retrieved to increase the reliability and robustness with noisy input data. Facial expression was recognized by fusing static and dynamic facial expression knowledge, the latter of which was learned by training a multi-class expressional Markov process using a video database. The experiments showed that facial motion tracking by OSM+CHM is more pose robust than that by OSM, and the facial expression score of the robust and precise algorithm is higher than those of other state-of-the-art facial expression recognition methods.

3D facial motion tracking by combining online appearance model and cylinder head model in particle filtering

A 3D facial motion tracking approach has been proposed based on the incorporation of online appearance model (OAM) and cylinder head model (CHM) in the framework of particle filtering. 1) For the construction of OAM, multi-measurements are infused to reduce the influence of lighting and person dependence. 2) The global motion acquired from CHM fitting is set as the initialization of OAM fitting, and the fitting result is set as the initialization of CHM in the next frame. 3) Motion filtering is applied with particle filter combined with local optimization and improved resampling. Objective between subjects evaluations show that our approach is fit to track facial motions.

Analysis of Thermal-Mechanism Coupled Stress Field of a Diesel Engine Cylinder Head

The paper analyzed the temperature field, the thermal stress field and the stress field under mechanical loads of a diesel engine cylinder head with finite element analysis software ANASYS, then took above temperature field results and mechanical loads as boundary conditions to impose on the established model of cylinder head using the thermal mechanism indirect coupled method, researched the stress field and distortion of cylinder head under effect of multiplicative loads. The result indicates that the point of the highest temperature and the maximum thermal stress locates on the middle nose of fire deck; under thermal mechanism coupled effect, the points of maximum stress locate on the interface of bolt head and screw of cylinder head and on the middle nose of fire deck; the maximum pull stress the cylinder head undertook is less than that the material can survive; the distortion of the cylinder head is very small, thus has little influence on the fabrication of other accessories, and the global distortion of cylinder head performs symmetry.

Temperature Field Analysis of High-Speed Gasoline Engine Cylinder Head Based on Fluid-Solid Coupling

As the important part of the internal-combustion engine, cylinder head bears high thermal loads and mechanical loads. In order to analyse the merits or defects of cylinder head cooling system , built the 3-D model of cylinder head, and analysed the heat transfer processes between cylinder head and cooling water by fluid-solid coupled simulation in STAR-CCM+. The pressure nephograms and velocity vector of cooling water in the water jacket, and the whole temperature distributions of cylinder head were acquired. And analysed separately the temperature fields of fire power faces and exhaust passages which were under high heat loads .According to the analysis results , the structrue of cylinder head water jacket was evaluated and corresponding suggestions was put forward.

Simulation Study on the Fluid-Solid Coupled Heat Transfer of Cylinder Head

The 3D model of cylinder head and cooling water channel is built in the Pro / E software, the channel model is trimmed and divided to get the grid correspond with the computational requirements in the ICEM CFD, the fluid solving parameters and boundary conditions and other related information is set in the CFX software, the solid domain and the coupling parameter is set in the ANSYS MFX module, then the temperature field of cylinder head and waterways, wall convection heat transfer coefficient and other information is got. The overall design’s rationality can be known from the temperature field, but between two outlets of the cylinder head, the highest temperature of the cooling water is 363K, it can be known from the flow of the cooling water that this part is not easy to be cooled, further improvement of the cylinder head structure should be made to improve the cooling effect of cylinder head.

Thermomechanical Fatigue Life Prediction of Cylinder Heads in Combustion Engines

While the deformation and damage behavior of aluminum cylinder heads under complex thermal mechanical loading has been the subject of numerous studies in the past, cast iron cylinder heads have been in the focus of thermomechanical fatigue (TMF) only to a minor extent. In this paper, a feasible procedure is presented to set up material models and estimate service life of cast iron cylinder heads under variable thermomechanical loading conditions by the use of computer-aided engineering tools. In addition, the influence of thermal load and mechanical constraints on TMF life span is shown. A specimen model is used for parameter identification in material model setup and a cylinder head model is used for correlation with cracking phenomena. Investigation of different thermomechanical load influences is conducted on the cylinder head model. The principal strain and energy based fatigue criteria are used in assessment of TMF lifetime for the cast iron family and material specific evaluation procedures are pointed out. The results highlight the importance of exact definitions of the boundary conditions and underline the sensitivity of TMF lifespan of cast iron cylinder heads with respect to the defined boundary conditions. Considering this sensitivity, an approach conforming to the engine development requirements is proposed. It is shown that both the crack location and fatigue lifetime are predicted with high accuracy.