Research On Gasoline Vapor Detection Based On NDIR Technology

With the improvement of people's living standards,the demand for oil has increased dramatically,and petroleum products have been applied to all aspects of life,but volatilization of gasoline vapors is an important factor in environmental pollution.Long-term exposure to naphthenes or aromatic hydrocarbons in gasoline vapors not only causes people to breathe problems,but also induces a variety of cancers.In addition,during the process of storage and transportation of gasoline,gasoline vapors easily lead to serious accidents such as explosions,causing huge losses.The measurement of gasoline vapors concentration is of great significance for the storage and processing of petroleum.By comparing the commonly used methods of oil and gas concentration detection,this thesis designs a high-precision non-dispersive infrared gasoline vapors sensor based on the principle of non-dispersive infrared to detect the gasoline vapors concentration.The infrared absorption method has the advantages of high precision,fast response and simple operation.Based on the analysis of the infrared principle,this paper proposes the overall design of the sensor,and researches and designs the optical path structure and hardware structure of the system.Among them,the infrared light source,infrared detector,filter and MCU,memory chip,filter chip and other devices in the sensor are selected.In order to reduce the volume of the sensor system,the gas chamber is designed as a reflective light source structure.According to the working principle of infrared light source and infrared detector,the driving circuit of infrared light source is designed to improve the stability of infrared light source.In order to improve the stability of the sensor,this paper builds a sensor test platform and measures a large number of experimental data of the designed sensor.Firstly,the working condition of the sensor system is tested at normal temperature,and the data is fitted to the sensor according to the test result,and the relationship between the gasoline vapors concentration and the sensor output at normal temperature is obtained.Then,the output of the sensor system at different temperatures is tested,and the temperature is studied.The effect on the sensor system is finally temperature compensated for the sensor.Experiments show that temperature compensation can eliminate the influence of temperature on the sensor and improve the stability.The measurement accuracy of the sensor system designed in this paper has reached the expected target at different temperatures.The sensor has good adaptability and certain portability.