Thinking about engine fires
 

Replacing all the old fuel lines seems essential. Some kind of builtin fire suppression system maybe the best way to go. What I am thinking about is something in the middle, a good extinguisher and some kind of enhanced delivery system short of a fully plumbed system. Some kind of pipe maybe that could be accessed from the outside of the car without opening the hood and would direct the contents of any fire retardant directly to the danger area at the top of the motor.

Getting rid of the valley or draining it or something might be good too.

For an extinguishers I'm thinking Halon if I can find it, still sold for boats isn't it?

I've resisted buying dry chemical in the past, since just about anything you spray it on is ruined as much from it as fire. CO2 doesn't sound like its very effective though. Any thoughts?

Perhaps you could rig a garden hose [I'm not being silly...] with a simple garden hose "Y" that would point to both sides of the engine near the point where the fragile fuel lines are located. Run it through the firewall somewhere, and have the end hidden under the dash somewhere.

Here's how it works: If you think that you have a fire...pull your Halon 1211 fire extinguisher [www.sportys.com; go to "pilot shop" and do a search for "halon fire extinguisher". These are aviation TSO'ed fire extinguishers, and use halon 1211. Cheapest is $80] and point it into the hose. Pull the trigger, and you flood your engine bay with oxygen-absorbing halon. DONT open your hood- the halon will stop the flames instantly and prevent them from coming back as long as you keep the hood down. If your ignition is off, the fuel will stop flowing quickly and you'll save your car.

Just a thought...

I'm not so sure I want the hole through the firewall, or the input to the fire putting out tube inside the car. As soon as I know its on fire, priority one is ME getting out.

How about running the "green" wire through a thermal switch so the fuel pumps cut out if the under hood temp is more than 300+ or so? Electric fans could be real pesky too.

Main obstacle to shooting a fire extinguisher from the front are the AC and coolant radiators, something just going from the inside of the nose and past the radiators might do the job, especially with halon. Actually, I guess the halon or CO2 would go past the radiators fine, just not dry chemical.

My Halon set up can support a nozzle for the cabin and engine compartment. However I only have one nozzle on the track car that is in the cabin. If there was ever a fire, I want all available Halon on my A$$....

The thermal switch idea isn't a bad one. The green wire isn't driving the fuel pumps though. You could probably also use it to open a solenoid for the halon.

I agree that if the car catches on fire, most people would be freaking out too much to have the clarity to pump your fire extinguisher through a hose.

I have already installed such a system about a year ago. I have a 2.5lb Halon 1211 extinguisher mounted quick release on the front of the passenger seat. It has an integrated quick release hose/nozzle attachment. In the drivers footwell a pull out female quick release port is plumbed with braided stainless steel covered rubber hose to the drivers wheelwell & engine compartment through the bulkhead and T splits to 2 nozzles in the bulkhead jetting forward under the intake pipes & along the fuel rails.

Getting out of the car first is a thought - but what if you can't??

Having the extingisher be handheld & the flex hose gives you other fire fighting options too - interior, yourself, CE panel or others cars etc...

The whole deployment system plumbing cost probably <$50 in readly available hardware store parts.. installation was work but not really too hard.

The most expensive parts of the system were - the B-K quick release seat attachment and the halon extinguisher. Total fo everything <$400.

As to cutting off the fuel pumps - it automatically cuts off when the engine stops and when you turn off the ignition - good enough for me.

Much more important to me ( but not yet done) is a fire detection system - its not always immediately so obvious you are on fire - esecially while driving along at speed (all the smoke is behind). Options are ionization or photo-electric smoke detection (rear bottom of engine) & heat detection (absolute and/or rate of temp rise types) at top of engine.

I do also carry a small 1lb dry chemical extinguisher to spray on other people/cars...

Alan

I suspect the normal under hood conditions are too much like smoke for most detectors to work, but come to think of it what we want to detect isn't fire, its gasoline, except for electrical fires.

Temperature rise for a fire must be 400+ I would guess.

I wonder how hard it is to detect gasoline?

Danglerb - I don't think so - there is nothing like smoke in a well functioning engine comapartment (sans oil drip on the headers). Remember there is quite a lot of airflow across the engine and most of it exits down & under the car - flushing fast

I consider the most likely design I will do will be a combination of several detection techniques. Absolute temperature is easy to do with thermal switches - probably set at about 300F on a few very thin heatsinks at the top of the engine.

Rate of temp rise detectors are perhaps the most promising - they integrate temperature changes over time for one or more sensors to try to detect engine bay temps rising faster than the thermal inertia of the engine alone should allow. They are not commecrcially available cheaply though and will be tricky to get set up right.

Cheap commercially available ionization and photo-electric smoke detectors can also be used for smoke rather than heat detection.

My thought is a color coded warning - prob in a spare pod spot that gives you indication of several of these in combination. If several different technology sensors go off the likelihood of a false alarm is relatively low.

But certainly detecting smoke could just mean you drove through some some actual smoke or are following somthing with a particularly dirty exhaust...

Idea here is just an extra input for the driver to decide on... Automatic systems are quite problematic - If I'm going to deploy $60 worth of Halon I want to be the one to decide if/when to do it... if you are driving at any forward speed the halon will all dissapear behind you very fast anyway

Alan

False alarms during the heat soak after a car is parked is what I am thinking about.

A few links to various.
http://www.ansul.com/en/Products/nonroad_sys/nonroad.asp
http://www.pierreford.com/special.cfm?ID=2791
http://www.afs1993.com/vehicle-fire-systems.asp
http://www.kellysearch.com/us-product-101798.html

My wild guess is that gas spills about half a dozen times more frequently than starting fires, but I haven't found much yet on detecting gasoline or gasoline vapors (haven't searched real hard yet either though).

How is this idea for a wacky fire suppression system, divert the exhaust to the engine compartment and stop the fan. Exhaust is hot, but not much O2 left.

You raise a good point - here is an example that would work - ~$200 .. not too bad.

http://www.discount-marine.co.nz/catalog/product_info.php?cPath=59&products_id=2893&PHPSESS ID=4e0739336cee3389fcac3785548f509f

They also have version with automatic gas shutoff valve control and gas flow valves...

For the same reasons I'd prefer not to do this - imagine how often you've smelled gas fumes while behind old carburated cars that aren't running well...
I for one wouldn't want to have my car shutdown suddenly in that case...

However its a good additional (and leading indicator) of fire risk - thanks for the idea.

The other thing that came to me yesterday was the thought that you need a way to stop the cooling fans while deploying halon into the engine... I need to think about this one. Could be as simple as having the fire detection system automatically disable the fan after running...

Alan

Alan,

Would you mind posting a picture of that? Sounds ideal!

Here area few:

Halon Extinguisher w/ Hose & Q-R nozzle and B-K quick release seat mounting:

http://www.moore-fun.net/images/Porsche/DSCN4292.JPGhttp://www.moore-fun.net/images/Porsche/DSCN4303.JPG

http://www.moore-fun.net/images/Porsche/DSCN4376.JPG

http://www.moore-fun.net/images/Porsche/DSCN4373.JPG

The Plumbing:

http://www.moore-fun.net/images/Porsche/DSCN3852.JPG

http://www.moore-fun.net/images/Porsche/DSCN3967.JPG

http://www.moore-fun.net/images/DSCN3962.JPG

http://www.moore-fun.net/images/Porsche/DSCN3874.JPG

http://www.moore-fun.net/images/DSCN3920.JPG

http://www.moore-fun.net/images/DSCN3878.JPG

Alan

While for "just anyone" this is probably true.. I'm the only one who drives my car and I would certainly both remember and execute on this.

Its not a good solution for general automotive use - I understand that... but as a means for me to save my 'baby' - it will work better than most alternatives...

Alan

If it gives you peace of mind, 90% of the job is done.

I have supplied hundreds of the replacement fuel line kits World Wide in the last 6 months.
Kits available for the 85 to 85 cars ($52.75) and 87 to 95 cars ($77.75).
Cheap insurance in my book and buys time until you fit Alans kit.

Roger - More than that - prevention is better than any cure - so fresh fuel lines are step 1 - mine have been replaced within the lsst 2 years and I do look them over periodically too.

However there are still other fire risks - so even then being prepared is good - pick your level of readiness...

Roger for your GTS you should really do this too... "belt & braces" as they say in the old country...

(belt & suspenders just conjours up a whole different idea for me ...probably for you too...)

Alan

Anyone need a good clean agent, halon or halotron?