The Study Of On-line Lubricating Oil Viscosity Sensor

As one of the seven major parts of the engine,lubricating oil can reduce the wear between the parts when the engine is running.In order to ensure the smooth and normal operation of the engine,the lubricating oil must have good performance.However,with the accumulation of engine working hours,the comprehensive performance of the lubricating oil will continue to decline,the lubrication performance will be greatly reduced,and there will be surface Wear,glue,and even plastic deformation,etc.If the lubricating oil cannot be replaced in time,more dangerous accidents may come into reality.Therefore,it is very necessary to conduct on-line detection of lubricating oil viscosity,and the existing viscometers on the market can only measure with sampling,and the lubricating oil must be in a laminar flow state.In response to these problems,this paper has carried out research on lubricating oil viscosity detection technology.The main contents include:Starting from the traditional rotational viscosity measurement method,using boundary layer theory and Reynolds equation,analyzing and calculating the rotor’s motion state,and combining with brushless motor Operation principle,design solutions.The solution uses a brushless motor to drive the rotor to rotate in the oil.Due to the different viscous torque of the rotor,the current value through the motor is different.The viscosity of the oil is obtained by measuring the current flowing through the brushless motor and substituting it into the calibration equation while the rotor is stable.For the whole set of sensors,the structure of the rotor determines the feasibility and accuracy of the measurement,and these are inseparable from the viscous torque experienced by the rotor.Based on the traditional rotor shape,this paper proposes four new rotor structures,and uses the workbench module in Ansys to simulate these rotors to obtain the simulation conditions of the rotors under different viscosities.Then set up an experimental platform to test,compare the test situation with the simulation situation,the analysis shows that each type of rotor has a certain resolution,and the detection effect of high viscosity is general,and the detection effect of low viscosity is good.Specifically,the detection accuracy of the four rotors at 30°C to 80°C is roughly the same,while at 80°C to 100°C,the detection effect of the No.2rotor is obviously better,and the resolution is as high as 0.0226 A/(mm~2/s).In terms of sensor hardware design and selection,a single-chip microcomputer with STC89C51 chip is selected as the main controller,and WCS2702 current detection module is added as the main hardware.A test platform is built to conduct calibration and verification tests after the circuit is connected.Comparing the test value and the standard value with each other,it is found that the overall measurement error is between 0.69%and 4.63%,and the whole set of equipment has a high detection accuracy.