scholarly journals Failure Analysis of a Modern High Performance Diesel Engine Cylinder Head

2014 ◽  
Vol 6 ◽  
pp. 862853 ◽  
Author(s):  
Bingbin Guo ◽  
Weizheng Zhang ◽  
Xiaosong Wang
Keyword(s):  
Diesel Engine ◽  
Failure Analysis ◽  
Cylinder Head ◽  
High Performance ◽  
Casting Process ◽  
Structure Type ◽  
Maximum Temperature ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Engine Cylinder

This paper presents a failure analysis on a modern high performance diesel engine cylinder head made of gray cast iron. Cracks appeared intensively at the intersection of two exhaust passages in the cylinder head. The metallurgical examination was conducted in the crack origin zone and other zones. Meanwhile, the load state of the failure part of the cylinder head was determined through the Finite Element Analysis. The results showed that both the point of the maximum temperature and the point of the maximum thermal-mechanical coupling stress were not in the crack position. The excessive load was not the main cause of the failure. The large cooling rate in the casting process created an abnormal graphite zone that existed below the surface of the exhaust passage (about 1.1 mm depth), which led to the fracture of the cylinder head. In the fractured area, there were a large number of casting defects (dip sand, voids, etc.) and inferior graphite structure (type D, type E) which caused stress concentration. Moreover, high temperature gas entered the cracks, which caused material corrosion, material oxidization, and crack propagation. Finally, premature fracture of the cylinder head took place.

Finite Element Analysis of Diesel Engine Cylinder Head Stress and Deformation with Thermal-Mechanical Coupling

2011 ◽  
Vol 211-212 ◽  
pp. 190-194
Author(s):  
Guang Hui Xue ◽  
Xiang Song Yu ◽  
Pu Sheng Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Diesel Engine ◽  
Cylinder Head ◽  
Fuel Injector ◽  
Element Analysis ◽  
Face Surface ◽  
Mechanical Coupling ◽  
Engine Cylinder ◽  
Stress And Deformation

Considering the structure of some diesel engine cylinder head, its 3-D solid model and the finite element model is built, and after the load and constraint of is deal with, the stress and deformation the cylinder head with thermal-mechanical coupling is calculated with FEA ( Finite Element Analysis) software ABQUS. Analysis results find that: (1) the first main stress maximum value of cylinder head is up to 199.6MPa, which is less than 250MPa of the HT250 material ultimate tensile strength; (2) the deformation area is mainly in the flame face surface and fuel injector coxcombing, and the deformation of flame face is general symmetrical broadways and slightly large near the exhaust passage longways, while the deformation of fuel injector coxcombing is general symmetrical broadways and longways; (3) the structure design and strength of the cylinder head satisfy the design requirements.

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

2013 ◽  
Vol 401-403 ◽  
pp. 59-64
Author(s):  
Qi Liu ◽  
Guang Yao Ouyang ◽  
Ping Zhang
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Diesel Engine ◽  
Stress Field ◽  
Cylinder Head ◽  
Element Analysis ◽  
Mechanical Loads ◽  
Thermal Stress Field ◽  
Engine Cylinder ◽  
Thermal Mechanism

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.

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