Research And Design Of Automobile Fire Alarm And Automatic Fire Extinguishing System

In recent years,due to the improvement of people's living standards,their demands for cars are so strong that make Chinese car possession increase continuously.However,when people enjoy the convenience of the cars,there are frequent fire accidents followed at the same time,which can cause a lot of economic losses and casualties.Therefore,it is significant to find an energy-saving,safe and reliable fire prevention and extinguishing solution to lower the frequency of automobile fires and reduce the economic losses and casualties caused by automobile fires.Based on the analysis of automobile fire characteristics,an automobile fire prevention and extinguishing proposal which can realize multi-level early warnings is put forward in this paper.Through the fire test simulations of automobile engine compartment,the work reliability of this proposal is proved and the alarm function and extinguishing function are optimized at the same time.The main findings are as follows:(1)Combining with three fire elements and car composition characteristics,it is found that the occurrence of car fires are caused by electrical system failures,overheating due to exhaust system and mechanical friction,high temperature and external fire sources igniting leakage fuel,car grease,other internal combustible materials or something like these.(2)According to the different types of combustible materials that cause automobile fires,car fires are classified into Class A(combustible solid materials)fire,Class B(combustible liquid materials)fire,Class C(combustible gas materials)fire,Class E(electrical appliances)fire.(3)Car fires have the following five characteristics:a.sudden;b.catch fire fast,burn fiercely,and spread rapidly;c.engine parts are easy to catch fire;d.the toxic smoke produced can poison people;e.lead to great losses.(4)The difficulties of dealing with car fires are detection difficulties at the start of fires,extinguishing difficulties,and lacked effective equipments.(5)According to the previous theoretical analysis and combined with actual needs,the functional requirements and the general program design of automobile fire alarm and automatic fire extinguishing system are determined,and then prototype design of this system is conducted.The system consists of automobile fire alarm system and automatic fire extinguishing device.The automobile fire alarm system is composed of fire detection module and fire alarm controller.The fire detection module consists of 138?non-renewable temperature cable and DS18B20 temperature sensor and has multi-level alarm function.The core of fire alarm controller is STC15W4K60S4 single-chip,3.2-inch USARTHMI touch screen is used in alarm display module,the battery which provides +12V power supply that converts into +5V to fit the system is used as the main power supply,and the power bank which is solar energy rechargable is used as spare power supply to provide stable +5 V voltage.According to characteristics of the automobile engine compartment,S-type hot aerosol automatic extinguishing device is selected.(6)A fire test was conducted to check the design of automobile fire alarm and automatic fire extinguishing system.By testing under different working conditions,the influence of extinguishing agent amount,way of spraying,position and quantity of fire sources on system's extinguishing effect were analyzed,as well as the influence of the way of layout,position and quantity of fire sources on length of alarm time.The test results verified the reliability of the system's performance,and the alarm function and extinguishing function were optimized after the test.An energy-saving,safe and reliable automobile fire prevention and extinguishing solution is proposed.