Simulation Analysis Of The Balance And Overall Vibration Performance On Five-cylinder Diesel Engine

With the rapid development of national economy and social increasing demand forproduct diversification, the reciprocating inline five cylinder engine is getting more andmore attention over the last decade. Developed automobile industry countries havedeveloped both compact and lightweight inline five cylinder engine to meet the requirementsof the engine power, economy and emissions,which is not only stable operation but lownoise and vibration.Inline five cylinder engine can replace the four cylinder engine andsix cylinder engine and becomes a complement of both. Rotary inertia force andreciprocating inertia force are cyclical because of the cyclicity of the reciprocating internalcombustion engine and the cyclicity of mechanical movement.The force of support will alsochange cyclically and cause of imbalance vibration of the reciprocating internal combustionengine.Firstly,this paper detailedly analyse the internal incentive causing unbalance vibrationof the five cylinder diesel machine according to dCi type five cylinder dieselengine.Then,this paper design some appropriate balance measures for each unbalancedforce.Build finite element model of the engine parts and condence the model using finiteelement analysis software ANSYS.Finally, build multi body dynamics model and made adetailed balance and vibration simulation analysis of dCi five cylinder type diesel engine.The first order and second order inertia force or torque are the main factors of enginevibration,but the vibration caused by higher order inertia force and torque can be ignoreddue to its smaller value. The number of five cylinder engine crank is odd and the crank is notcompletely symmetrical. So the engine have reciprocating inertia torque compared tofour cylinder engine and six cylinder engine.The torque is cyclical and produce a vibratoryeffect. First order reciprocating inertia torque use excess balance method. Excess centrifugalquality have four parts and is arranged in the balance weight of the first and fifth crank. The second order reciprocating inertia torque is balanced by two balance shafts. Balance shaftsare symmetrically arranged on both sides of the engine and twice in the rotation ofcrankshaft speed. Rotary inertia force of the crankshaft takes complete balance method.Finite element model is the basis of finite element analysis. The position and the settingof master nodes and master degrees of freedom should be specially considered based on therequirements of the multi body dynamics software EXCITE. The number of degrees offreedom of the mechanical structure is large.Using matrix condensation to reduce the hugenumber of degrees of freedom is necessary for computer configuration, while multi bodydynamics calculation requirements of the computer is higher than static calculation.This paper analyzes the damping effect of the balance measures for the first order andsecond order reciprocating inertia torque based on AVL/EXCITE. Excessive centrifugalmass has a slightly increased affect to second order and higher order vibration, when itreduce first order vibration. Balance shaft design for the second order reciprocating inertiatorque is significant. Reciprocating inertia torque and overturn torque are the main reason ofthe dCi type five cylinder diesel engine mechanical vibration through analysis.The balanceshaft can cut half of the vibration caused by reciprocating inertia torque and we need goodelastic support for the overturn torque.