Research On On-line Detection Sensor Of Engine Lubricating Oil Viscosity

Lubrication system is one of the five systems of engine,which plays an important role in the normal operation of internal combustion engine.The main functions of lubricating oil are lubrication and wear reduction,shock absorption and buffer,cooling and cooling,sealing and leakage prevention,cleaning,rust prevention and corrosion prevention,etc.Therefore,the performance of lubricating oil is the premise to ensure the normal operation of the engine.However,its lubricating performance will gradually become poo rwith the increase of service time,which will easily aggravate the engine wear and even cause engine failure.It is very important to measure the viscosity of lubricating oil on line.The main research is to design an on-line sensor for measuring the viscosity of engine lubricating oil,including:Based on the traditional rotation method,an indirect measurement method of oil viscosity is proposed by calculating the current in the circuit.Analyzing the flow state and viscous moment of the rotor rotating in the oil by the boundary layer theory and Reynolds equation.Determining the relationship between the viscosity of lubricating oil and the speed,torque and current of sensor motor by using the working characteristics of DC motor.Establish the mathematical model of the sensor and usingthe flat perforated rotor to study and verify the feasibility of the design scheme.Through the analysis of the number of holes on the rotor,explaining that increasing the number of holes is conducive.Design four types of rotors and use Fluent to simulate and analyze the four rotors respectively.The best rotor was selected for further study and the equation between current and kinetic viscosity was established.Design and calculation of hardware and software for the sensor.Select single-chip computer STC89C52 as the controller of the main control module.Select WCS2702 current detection module as the main electronic component of the viscosity detection module.Select LCD12864 graphical LCD display as display.Select RS-232 standard interface and MAX232 level converter as the communication mid-end.Make the program design of the total control module and the viscosity detection module to ensure the normal operation of the viscosity detection device.Set up an experimental platform to detect lubricants with different viscosities.The results show that the viscosity detection device has good resolution for lubricants at different temperatures.Comparing the detected data with the simulated data,it is found that the overall error is less than 5%,which indicates that the experimental results are scientific,effective and have some repeatability.Calibrate the viscosity sensor,and fit the viscosity relationshipfunction between the current of the sensor and the oil,which is input into the single chip computer as the standard for re-measurement.The measurement accuracy of the sensor is verified by many experiments.The error of single measurement is not more than 10%,and the average error of multiple measurement is not more than 7%.This shows that the viscosity detection device can distinguish oil of different viscosities well and the error can be reduced effectively by many measurements.