Strength Analysis On The Crankshaftof YD4A Highly-intensifiedgb-iii Diesel Engine

As international crude price rises, urgent diesel demand emerges from such domestic models as pickup and light passenger car. To capture the market of such products, Yangdong Corporation develops a new high-duty diesel engine for YD4A-C3 light vehicles GB-III Emission Standard. Various indicators of the engine are greatly raise against the former model. Mechanical load sustained by the whole machine and the crankshaft is also increased in proportion, so the reliability of the crankshaft faces severe challenges. To reduce costs, the engine's crankshaft applies spheroidal cast iron, and the journal fillet undergoes rolling and strengthening treatment. As the strength of the crankshaft depends on the reliability of the diesel engine to an utmost extent, this paper conducts research on the strength of the crankshaft, to demonstrate whether or not the crankshaft is able to ensure safe, reliable operation of the diesel engine while requiring relatively low manufacturing costs.Based on a wide range of foreign and domestic literatures, this paper studies and compares various analysis methods of crankshaft strength. According to product development plans and research conditions of the enterprises, this paper adopts the analysis software of shafting dynamics Bricks by AVL Corporation, supported by the method of finite element analysis. First, it designs the crankshaft structure, and builds a three-dimensional CAD model. Then, it introduces CAD model into the finite element software, and accurately calculates bell crank rigidity and fillet stress concentration factor, which is used to analyze subsequent torsional vibration and strength. Next, it chooses a suitable torsional vibration damper to improve torsional vibration characteristic of the shafting on the basis of analysis of torsional vibration, and obtains safety factor of all fillet positions of the crankshaft through fatigue strength testing and calculation, based on which it judges whether or not the crankshaft may be subject to fatigue failure under high duty. Finally, the whole diesel engine endues durance test, to prove the reliability of the crankshaft. The result shows that after low-cost spheroidal cast iron crankshaft undergoes surface strengthening process, its strength can be greatly raised, so that the problem of crankshaft reliability brought about by high duty of the whole machine can be removed.