Lubricating Oil On-line Monitoring Method Based On Multi-parameter Fusion

As the deterioration of lubricant oil will damage the mechanical parts of the automobile,the quality of the automobile lubricant oil is significant for the normal driving,performance exploiting and the life span extending of the automobile,especially for commercial vehicle.However,there are several deficiencies in lubricant oil's replacement method.For example,the replacement of the automobile's lubricant oil is mostly judged by the mileage or time.At the same time,some commercial vehicles begin to research long-life lubricant oils,so the demand for accurately monitoring the deterioration of lubricant oils become stronger.Based on the existing dielectric constant sensor,viscosity sensor and humidity sensitive resistor,the main studies are as follows:(1)researched the relationship between the lubricant oil's degradation index and its dielectric constant and viscosity by simulation experiment.(2)researched the relationship between the humidity sensitive resistor's output voltage and the lubricant oil's water content.(3)established a relational model between the lubricant oil's degradation index and its dielectric constant and viscosity.In the end,the model is verified by the bench test data.And the polynomial model is obtained to get the lubricant oil's degradation index though dielectric constant,viscosity and the engine running time.This paper firstly selected the sensor,built the experimental platform,and designed the experimental scheme.In this paper,three sensors,the dielectric constant sensor,the viscosity sensor and the humidity sensitive resistor,were selected to conduct an experimental study on the lubricant oil.After the selection of the sensor was completed,an experimental bench was built and an experimental scheme was designed.The experimental program includes the preparation of the simulative lubricant oil samples that are degraded and measurement plan for oil samples.As for the preparation of the simulative lubricant oil samples that are degraded,it is necessary to determine the type of the sample,the pretreatment plan and time of the sample,the mixing time for the preparation of the oil sample,and the ratio of the oil sample.And the measurement plan for oil sample mainly includes the temperature point of the oil sample and how to measure the valid temperature data.This paper studied the single factor including water content,iron content,diesel content,carbon black content(used to simulate engine smoke plume)and the oxidation degree of the lubricant oil.This part mainly studied the relationship between these degradation indicators and the lubricant oil's electrical constants and viscosity through the simulation experiment and then established a mathematical model.In addition,the water content of lubricating oil was measured by humidity sensitive resistor,and the relationship between the output voltage of the humidity sensitive resistor and the water content of the lubricating oil was established.Then the effects of the two factors including carbon black content and diesel content on the new lubricant oil's dielectric constant and viscosity and the effects of the three factors including oxidation degree,diesel content,and carbon black content on the lubricant oil's dielectric constant and viscosity were studied.The data was analyzed to establish a mathematical model of the effects of the two factors of carbon black and diesel on the lubricating oil's dielectric constant and viscosity.And the mathematical model of the effects of the three factors of oxidation degree,diesel content and carbon black content on the lubricating oil's dielectric constant and viscosity was also established.Based on the above conclusion,the data of the degraded lubricating oil obtained by engine test bench was analyzed.What's more,the mathematics model established by multi-factor experiments of the simulated oil samples were verified and corrected.The mathematics model about the dielectric constant and viscosity and lubricating oil's degradation index(smoke content,oxidation degree,diesel content,p H,etc.)was solved.Finally through the further analysis of the data,the polynomial model of the lubricant oil's degradation index was established by the parameters such as the dielectric constant and the viscosity.