Research On The Dynamic Characteristics Of A Diesel Crankshaft System

One of the effective means to improve the single engine power is to develop long-stroke engine. After lengthening the stroke, diesel engine torsional vibration characteristics, bearing load and dynamic characteristics must be varied. So, to ensure the reliability of the crankshaft, the calculations and analysis of crankshaft dynamic characteristics is necessary in the process of the long-stroke crankshaft design.This thesis is about a certain type of long-stroke engine technology design, mainly include the following parts:Firstly, a substantiality single crank model is built, and the torsional stiffness and longitudinal stiffness are calculated by using the finite element method, then a diesel engine shafting eight cranks model is establishaed, and both models with flywheel and without flywheel are analysed.Secondly, the 12-V and 16-V diesel engine crankshaft models established are used for the analysis of torsional vibration. Using the FORTRAN procedures the free vibration and the forced vibration are both calculated, especially taking sequence ignition and interval ignition of the two cylinders linked to one crank into account, which influences the characteristic of shafting vibration mostly. Based on these results, the safety problem of the crankshaft torsional vibration is discussed.Finally, according to the conclusion of torsional vibration analysis, three bending moment equation model for the 16-V diesel engine was built, which is used to calculate the bearing load of two cylinder in a row sequence ignition, the shaft center trace is also calculated using the holland method. Some useful advice for the design process is given.