Method for testing oil-film force of piston assembly based on crankshaft vibration signal and system

Abstract

The invention discloses a method for testing the oil-film force of a piston assembly based on a crankshaft vibration signal. By using an offline emulation module of lubrication mechanics and dynamics equations of each component in an established piston-shaft system, the oil-film force (friction force and bearing force) of an internal combustion engine piston assembly can be obtained on line through a crankshaft vibration signal; the strong coupling of the lubrication mechanics and dynamics of each component in the piston-shaft system is considered comprehensively, and a new two-dimensional hybrid lubrication model is used, so that the online prediction operability of the oil-film force is enhanced, the two-dimensional oil-film force (circumferential and axial) of the internal combustion engine piston assembly can be obtained accurately simultaneously, and the problem of low accuracy of the oil-film force of the internal combustion engine piston assembly obtained with the conventional method is solved; and the oil-film force of the internal combustion engine piston assembly can be safely, reliably and accurately obtained on line by using each module of the system, a computer and a sensor in an online test analysis device, and the oil-film force obtaining cost is saved remarkably.

Description

technical field [0001] The invention relates to the field of oil film force testing, in particular to an online testing method for the oil film force of a piston assembly based on a crankshaft vibration signal, and also relates to an online testing system for the oil film force of a piston assembly by means of the crankshaft vibration signal. Background technique [0002] The internal combustion engine has been used for more than 100 years and has become the most widely used power plant. The piston-shaft system of the internal combustion engine (including piston rings, pistons, connecting rods, cranks and crankshafts) is the core mechanism system for the internal combustion engine to transmit power, and it is also the main source of power loss. Its performance directly affects the efficiency and life of the whole machine. . The application practice of internal combustion engines shows that the functional failure of various components of the piston-shaft system is often the ...

AI Technical Summary

Problems solved by technology

However, these methods either study the lubrication mechanical properties of the piston-shafting components in isolation, or study the dynamic properties of the piston-shafting components in isolation, while ignoring the strong coupling characteristics of the piston-shafting components’ lubrication mechanics and dynamics

Moreover, the various factors in the mixed lubrication equations used in these studies are only applicable to the ideal Gaussian rough surface of the piston assembly, and the elastic deformation of these surfaces and the cavitation of the lubricant are not considered.

In addition, most studies use one-dimensional lubrication models, which can only obtain circumferential or axial oil film forces

Due to the above reasons, the oil film force of the piston assembly predicted by conventional computer technology is often quite different from the actual measured value

At the same time, due to the long analysis time of this method, it is difficult to use it online

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