Connect-Rod Design Of The WP7 Type National III And IV Series Diesel Engines

Connect-rod is the important power-transmitting component of the engine which changes the linear movement of the piston into the rotary motion of the crankshaft and transmits the force on the piston to the crankshaft in order to output power.As the connect-rod bears the assembly load(including the surplus force of the bearing bush and pre-tightening load of the bolt) and repeated fluctuating load(including the exploding pressure of the gas and the inertial force) in the course of work,its running conditions are comparatively harsh.The modern cars are developing under the direction of environmental protection and energy conservation,which means not only the engine connect-rod has to be strong and stiff enough;it also has to be small-dimension and light-weight.It is therefore necessary to apply modern designing methods and technology to the development of the modern engine and its key parts.This paper focuses on the fact that in the designing of the connect-rod for WP7 Nationalâ…¢andâ…£series diesel engines,FEA is used to identify the reasonable thickness of the connect-rod small end,the connect-rod small end fillet,the connect-rod big end fillet and connect-rod big end form and supporting side forms of connect-rod big end,thereby it can both improve the stiffness and intension of the connect-rod and effectively control the weight.Main results of the paper are as follows:1.To prevent the small end fracture problem in the designing of connect-rod for the WP7 Nationalâ…¢andâ…£series diesel engines,it is found that when the link fillet is R65 mm and the thickness of the small end wall is 9mm,the safety factor of the small end achieves 2.0 through the finite element analysis of different thickness and the first link small fillet.And the safety factor satisfies the designing requirement.2.The safety factor of the connect-rod at big end is improved 40%and more when it adopts the half "å·¥" structure comparing to the circular structure,meanwhile the weight is lighter.The "å·¥" structure also can control the deformation of the hole at the big end.The safety factor of the supporting side for the large end of the connect-rod big end is also improved by adopting the semi-circular incision comparing to the direct incision.3.The RG safety factor of the common "å·¥" structure that WP7 Nationalâ…¢and â…£series diesel engines uses is above 1.5,which means the stability of the connect-rod meets the work requirement.