Tuesday, 7 April 2015

FIRED AUTOMOBILES


Off late we have come across many an accident in the press that does not involve any collision. Vehicles going up in flames, train compartments burning passengers alive, etc. There can be many causes for the fire, ranging from human causes, mechanical causes and chemical causes. All the causes can sometimes work together causing fire. Once a vehicle’s on fire, many factors tend to complicate it. But when you are inside and the car is on fire, it does not matter what caused it, your car is on fire. You have to get out and run as far away from the car as possible.

Design flaws do not directly cause fire. But these can create conditions for an inevitable fire. Several tests are made during design stages and if there are frequent complaints of a particular make of cars going ablaze, that particular brand of cars are recalled to get the problem fixed. The first to be checked always is a design flaw. But blaming the design of the vehicle or a component is not always the solution of a blaze.

Poor maintenance of the vehicle can also be clubbed as human error. It is the perfect example to show that laziness actually kills. Broken parts not replaced, leaky seals not fixed, faulty wiring not repaired are all recipes for fire. An engine with bad gasket drips the flammable fluids. Exposed wiring can spark and begin the fire. It is always recommended to keep up with the scheduled maintenance of the vehicle and also conduct regular checks under the hood for any damages.

The worst human “error” can be Arson. Just like in a movie where actor Vadivel sets a bike on fire playfully, ends up realizing the other person was seeking revenge. So if you own a car, better make sure you do not make any enemies, who in the name of revenge can roast you inside your own car.
An overheated catalytic converter is often overlooked as a cause. But with almost all of vehicles having a catalytic converter (due to pollution norms) and improper maintenance of engine (worn out spark plugs), unburnt fuel in the engine along with the usual suspects in the exhaust gas end up in the catalytic converter. The catalytic converter has to work more to break down the fuel and as a result heat up from the operating temperature range of 650oC-900oC to a temperature of over 1100oC. This causes long term damage to the converter and to the car as well. If the catalytic converter gets hot enough, it could ignite the cabin insulation and carpeting right through the heat shields and metal floor pan.

An overheated engine is one of the major cause of most fires. Engine can overheat due to improper coolant circulation, radiator malfunction or leaky seal or gasket. An overheated engine rises the temperatures of the lubricating oil and coolant. These oils can leak out in the engine bay or over exhaust systems, where it can attain its ignition temperature. Engine overheating generally occurs due to mechanical failure. But in modern cars, a software update or changing the ECU to regulate the temperature of the engine is enough to prevent the problem. But at the end of the day, taking the vehicle to the authorized service station is the best solution for the same.

Oil in the engine and coolant are not the only flammable fluids in your vehicle. Leak of transmission oil, brake fluid, power steering fluid, apart from the fuel itself, can also cause fire. For this to happen, something else should have gone wrong first. Like a car crash or a hit on the fluid line by a stone or culvert or a failed part result in leakage of fluid, resulting in fire. Though most of such blazes start from the engine bay, some can start from any length of the car as the brake line and the fuel line travel almost the entire length of the vehicle. But fuel system fire is the most common cause of vehicle fires. Fuel leaks can occur anywhere, anytime and without any warning, hence, making them dangerous. Fuel dripping on hot metal and plastic parts can cause a fast spreading fire. The best way to prevent fire due to fuel is by maintaining the vehicle properly. If you smell fuel in or around the car, find the leak and fix it immediately.

Electrical failures are equally dangerous as fuel leaks. Car batteries, especially in hybrid vehicles, are problematic. Battery’s charging cycles causes explosive hydrogen gas to build up in the engine bay. Electric current provided by the battery can produce sparks that can ignite fluid vapours or dripping fluid. Short circuit in electrical wiring running throughout the length of vehicle, through channels, into doors, under carpets, etc. can cause fire within minutes.

Therefore, preventing fire in your car does not depend on the availability of a fire extinguisher inside the car but on the periodic and proper maintenance of the vehicle.


NOTE: This post was first published for the MiTech Digest, A technical magazine for Madras Institute of Technology, Chennai. www.csmit.org/MiTechDigest

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