Analysis For Dynamic Characteristics Of A Single-cylinder Diesel Engine Crankshaft System

Single-cylinder testing machine is usually designed to be a single-cylinder diesel engine with a special structure; it is an important tool of exploring new type of diesel engines or improving performance and structural parameters of existing diesel engines. In order to make the diesel engines achieve the desired performance quickly, we should pay more attention to the research on the single-cylinder testing machine.In the process of designing a new diesel engine or improving the existing products, it is content variety, tuning of complex, workload and testing a long cycle to use the multi-cylinder machine to do the performance adjustment and structural parameters comparative testing. You can simplify the adjustment process if replace the same type of multi-cylinder testing machine by single-cylinder machines, and shorten the cycle of adjustment, carry out comparison of a large number of structural parameters and performance tuning easily. Crankshaft design is an important part of machine design, and we must face the design of crank train in the process of dynamic performance analysis, and strength and stiffness calculation. This paper, combining of finite element and flexible multi-body dynamic analysis method, analyze a certain combustion experiment of a single-cylinder diesel engine crankshaft system dynamics.We can effectively solve the contradictions between limited human and material resources and development speed through reasonable simplification of the crank train, high-quality meshing and FEA substructure technology. Different design objectives have different methods of calculation. This crankshaft of the single-cylinder testing machine which is evolved from the original V-crankshaft is used for some exploratory research and optimal design. In this paper, the traditional particle system of forces analysis model and flexible multi-body dynamic analysis model were made. First, get the natural frequency from the traditional Holzer method and physical model of the sub-structure method, and then they were contrasted and analyzed to verify the accuracy of the traditional model. Second, analyze the crank train of the single-cylinder diesel engine, which contains main bearings force, flywheel-side speed fluctuations, torsion and longitudinal vibration of the free end crankshaft, crankshaft dynamic stress and so on, through the calculation results of the particle force system analysis model and flexible multi-body dynamic analysis model. That has a certain reference value to design a single-cylinder machine. At last, we design a static stress experiment of the crankshaft. We found that the distribution of static stress is different from the dynamic stress?comparing the dynamic and static stress and experimental stress.