Inner surface stress and temperature monitoring method of internal combustion engine main bearing based on fiber bragg grating

Abstract

The invention provides an inner surface stress and temperature monitoring method of an internal combustion engine main bearing based on a fiber bragg grating. Fiber bragg grating strain sensors and fiber bragg grating temperature sensors for temperature compensation are respectively arranged on an internal surface of a to-be-tested main bearing so as to obtain strain changes of a bearing working surface; the fiber bragg grating strain sensors are arranged at all directions of the inner surface of a bearing so as to obtain the strain changes of the bearing at each direction; an engine oil temperature sensor is arranged in a waste engine oil pipe of the internal combustion engine so as to obtain engine oil temperature data; a fiber Bragg grating demodulation instrument is used to obtain center wavelength changes of the engine oil temperature sensor, and to convert the center wavelength changes into electrical signals; and engine oil temperature changes when the internal combustion engine works can be calculated. With the use of characteristics that the fiber bragg grating can simultaneously measure the strain and temperature and is small-sized and one-line-multi-point, the inner surface stress and temperature monitoring method of the internal combustion engine main bearing based on the fiber bragg grating can simultaneously monitor the temperature and strain distribution of the main bearing working when the internal combustion engine works, so as to provide accurate data to support optimization of the structural design of the internal combustion engine main bearing.

Description

technical field [0001] The invention belongs to the field of internal combustion engines, and in particular relates to a method for monitoring the strain and temperature of the internal surface of main bearings of internal combustion engines based on optical fiber gratings. Background technique [0002] In the internal combustion engine crankshaft system, the function of the main bearing is to support the crankshaft, ensure the working axis of the crankshaft, and make the crankshaft transmit power with small friction and wear during rotation. During the working process of the internal combustion engine, the main bearing is subjected to the gas force and inertial force from the crankshaft, as well as the friction force generated by the rotation of the crankshaft journal in the main bearing, so the main bearing bears a large load. In addition, the relative motion speed between the working surface of the main bearing and the journal working surface is very high, which not only ...

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Problems solved by technology

However, due to the limited structural space of this part, there is still a lack of direct monitoring data of the temperature and strain distribution on the surface of the main bearing. The determination of the above parameters mainly depends on the results of experience and numerical analysis.

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