Optimal Design of Crankshaft for a Single-cylinder Diesel Engine based on ANSYS

Junjie Chen; Xiaolong He; Weilin Guo; Xiaoqing Zhu

doi:10.6919/ICJE.202607_12(7).0014

Authors

Junjie Chen School of Intelligent Manufacturing and Engineering, Chongqing University of Arts and Sciences, Chongqing, 404100, China
Xiaolong He School of Intelligent Manufacturing and Engineering, Chongqing University of Arts and Sciences, Chongqing, 404100, China
Weilin Guo School of Intelligent Manufacturing and Engineering, Chongqing University of Arts and Sciences, Chongqing, 404100, China
Xiaoqing Zhu School of Intelligent Manufacturing and Engineering, Chongqing University of Arts and Sciences, Chongqing, 404100, China

DOI:

https://doi.org/10.6919/ICJE.202607_12(7).0014

Keywords:

Crankshaft; Finite Element; Optimal Design; Statics; Light Weighting.

Abstract

The present paper discusses the critical prerequisites to improve lightweight design and structural reliability of the crankshaft of the single-cylinder diesel engines. Using ANSYS Workbench finite element analysis software, a three-dimensional solid model of the crankshaft is created and then static finite element analysis is done to determine the stress distribution when subjected to working conditions under real-life conditions. As shown by the findings, the highest value of the equivalent stress of the original crankshaft is 100.16 MPa and the least value of the safety factor is only 2.49. Moreover, there is a high level of stress concentration where the crankshaft meets both the main journal and crank pin, which can cause fatigue failure after many operating hours and negatively impact the lifespan of the diesel engine. These problems are solved with a specific optimization strategy, taking into account the features of stress distribution. Stress concentration regions are relieved using transition fillets to reduce local stress fluctuations. Also, the stress relief slots are provided at the crank arm to distribute the concentrated stress. At the same time, the diameter of the crank pin and main journal was optimized to make light weight at the cost of structural integrity. After optimization, the static finite element analysis was carried out to confirm the outcomes. It was found that the maximum equivalent stress of the crankshaft has been minimized to 87.713 MPa and the smallest safety factor was raised to 2.85, which greatly improved the reliability of structures. Simultaneously, the total mass of the crankshaft was decreased by 9.3% thus accomplishing the aim of light weighting. This study successfully resolves the trade-off between lightweight design and reliability of the crankshaft of the single-cylinder diesel engine by combining finite element analysis with structural optimization. The suggested optimization scheme is scientifically justified and feasible, and can be used as a dependable engineering guide to the best design of a crankshaft of a single-cylinder diesel engine, and it can be regarded as very valuable to improve the performance of diesel engines in general.

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