Cylinder Head Failure Analysis And Structure Improving Assessment Of CY4102BZL Diesel Engine

This paper aims at the cylinder head crack failure which happened mainly in CY4102BZL TCI diesel engine, by means of testing and analysis, lose effictiveness analysis of the broken section with electrical measuring technology as well as later FE calculation of orginal proposal, thus the reason of losting effectively from many angles: under the prereauisite of fire pressure increased greatly, the top plate of such cylinder head can't effectively coordinate deformation, hence leads to the crack sprout from inside of the water chamber, then expands to the top, it is caused by mechanical load.Further improvement in the strucure is the find measure to solve crack problem in the head. We start from the basic bearing force structure of the heads, carefully study possible deformation tendency of the the head under the pretight mode and bearing max gas pressure mode, we also carefully study the distribution and regular pattern of deformation in high stress area cause by such case, we especially study the stress state and deformation in the crack area of two heads, several improving proposals are work out so as to increate the strength and reliability as big as possible with minimum process cost.In order to get exact quantitative improved data, especially the stresss value and stress direction in original crack of broken erea, by means of FE, a mathematic model of the frginal head is created strictly as per the drawings, followed by improvement on the basis of improving proposal. By means of original proposal calculation with FE and verification with electric measured datak, the truthfulness and reliablity of the calcultiong result and the original stress state are first verified. Then several proposals are compared and caculation, a judement is made by quantity that the stress step of top and low surface of the improving proposal in broken area is reduced greatly compare with original proposal, the total stress level and the deformation of the head tends reasonable. Through reliability analysis, F3 is the best proposal operation requirement of current cylinder head.