AUTOMOBILE FIRE ACCIDENTS AND OCCUPANT SAFETY

摘要

Automobile fire, an uncontrolled burning of the vehicle has long been a topic of interest and concern. Car fires can be caused due to Fuel system leaks, Engine overheating, Electrical system failures and accidents. It is a surprising fact that in many car fire cases, except for some major accidents, the occupants are conscious enough to get out of the car but still they fail to extricate themselves. When we analyzed the fatality instances, investigations/eyewitness reports revealed that vehicle occupants were entrapped in car due to jammed Doors. In some cases, even onlookers were unable to open the door from outside to help the occupants escape. Also, the Society of Indian Manufacturers (SIAM) Research Study reveals that majority of car fire accident fatalities are due to doors getting jammed. In countries like India, where installing Glass breaking Hammer in a vehicle is not mandatory, the threat posed by car fire to Occupant safety is very serious. Analyzing the customer's/eyewitness voice, we are bound to believe that even the mechanical door unlock system fails in case of fire. There are certain drawbacks in the current door opening mechanism. While opening the door, the pull of inside handle actuates the Latch pawl mechanism through other sub components. In general, the components involved in this mechanism are made up of Plastic. Any Deformation or melting of Plastic parts can make the entire system inoperative and result in failure of door opening. The same phenomenon holds true for door outside handle operation. The main purpose of this thesis is to understand the failure of operation of current system in fire accidents and develop a mechanism to operate the door latch even if it catches fire or electrical system fails to operate it. The idea is to manually actuate the pawl directly with the help of a key or selectively improving the material to withstand the fire temperature. Part level simulation of fire accident was conducted on the existing Mechanism in the lab and it resulted in the failure of door opening. However, the actual vehicles which were damaged in the fire accident were not examined. And also, there are less than 10% of vehicle fires which are caused by collisions. There may be cases where the door unlock mechanism gets physically deformed due to severe impact of collision. In such unavoidable cases, the proposed mechanism may physically deform and fail to serve the purpose. This paper elaborates the approach to the main cause and provides an innovative solution to overcome. Related ideas to unlock the door during emergency fire exit involve either complicated sensors & feedback system or Pyrotechnic telescopic actuators which are quite bulky, complex and not feasible for mass production. The proposed mechanism eliminates the use of complex feedback system and integrates the operations inside a single component. Also, it is necessary to adopt the safety system in Lower segment cars - where the manufacturer is less likely to use a complex feedback system due to its cost factor. So, this mechanism paves way to manufacturers to consider the necessary safety system at affordable cost.