Research On Portable Engine Oil Quality Detector

Abstract:In the process of using engine oil, not only to withstand the high temperature, high pressure and vibration effect,but also with the pollution of oxides, water, additives, dust, soot metal particles and fuel. Therefore, the performance of engine oil will change, including the effect of original lubrication will be reduced, it will influent the life and efficiency of the engine. So it is necessary to check the oil level and the degree of contamination, and this is the reason why should change engine oil regularly.At present, there are mainly two ways to detecting the engine oil quality:one is the chemical analysis, which is periodically sampling the engine oil to analyze its physical and chemical parameters; the other is the empirical method, judged by the engine running time or the mileage, such as5000km. The chemical analysis requires the specialized chemical analysis equipment, which has complicated operation and low efficiency, and though the empirical method is simple and scientific, but it is not accurate enough, easily lead to change oil too early or too late. This thesis is proposed on the condition of increasingly using the engine oil and the existed detecting engine oil methods are not easy to carry, and the high cost, aimed to design a high precision and portable engine oil detector.This paper firstly gives an introduction of the engine oil judgment among the domestic and foreign, and the aging mechanism of oil is analyzed emphatically. Through the analysis of the advantages and disadvantages of the existing popular oil judgment of domestic and oversea, this paper introduces an portable engine oil quality detector for the car which is based on the dielectric constant and viscosity of the oil, meanwhile, the theoretical basis of the engine oil quality judgment by dielectric constant and viscosity is also introduced too. Secondly, through the research of the design principles of the capacitive sensor and the single cylinder rotational viscometer, this paper designs a combination probe which is based on the integration of the capacitive sensors and viscometer probe. SolidWorks software is used to design the combination probe, and through the FLUENT software simulation, the torque specification of the gossamer is determined. Thirdly, the control system of the engine oil quality detector is designed, including the hardware and software. PIC30F4013microcontroller is used as the processing chip and the AD7746capacitance conversion chip is used in capacitive sensor measurement module. At the end, the experimental study on the portable engine oil quality detector measurement modules is studied, and through the comparison of measured data by the standard viscometer and bridge, the performance of the measurement modules is tested. And through the analysis of experimental data, the dielectric constant and viscosity of the oil pollution limits are initially identified.