12 to 16 explosive devices in our vehicles?

[Mr Big]

Wow. Please report incident to the NHTSA.

I did the day it happened!

 

[Trainmaster]

This is an interesting thread. I never heard of this happening but obviously it does. I'm a bit smarter from reading this.

 

[JamaicaJoe]

Don't see how I am "missing the point". Anyway, I am not buying a latest generation for my next vehcle. The sweet spots were 1st gen and certain years to 2014. Too much electronics and too much to fail. Good day sir..

 

[rd618]

Incindiary charges powering bags and tensioners have changed several times over the decades. Incindiaries used in modern (20teens+) vehicles are made up of primarily Guanidinium Nitrate, which is basically solid rocket fuel. Many of the combustion gases produced are the same or similar to those produced by modern smokeless gunpowders, so, a closed vehicle that has cycled one or more of its incindiaries will smell similar to burnt gun powder.

Correct, I’m familiar with them, the goal of these propellents is to create nitrogen in fast and high volume, I’m not familiar with it used in any rocket propulsion, but seems possible.
My point is that while these do exist and serve a value, people should not assume they are riding around with live ammunition aimed at them or that it will in any way compromise their fuel tank. That’s not a true picture at all.
As for the smell, yes absolutely could smell similar.

 

[rd618]

There absolutely is a substance similar to gun power in the pretensioner and you can smell it when it goes off. It is a pyrotechnic explosive device,

I am not arguing the smell of the resulting explosion, your comment “12 to 16 on board explosive devices that use gun powder.” is not accurate, they don’t use gunpowder or smokeless powder, they use guanidinium nitrate. While there may be some loose commonalities, they are not the same thing.

The computer used in cars is very similar to any PC, tablet or cellphone, with an operating system, processor and ram, reacting on signals and commands true or false. The short sent a signal to the computer and the computer reacted.

I’m not sure that’s how it works. I’m a bit outside my depth but the computer needs a reading not just a “short” to tell it how to react. For example, why did only the seatbelt go off then and not the airbag? If the short sent a “collision” reading wouldn’t both be triggered? If not then I’m assuming the short sent a specific signal that implied it was enough for the seatbelt but only driver side and not enough for the airbag? More likely the short simply triggered the charge directly to the pretensioner, bypassing the computer all together. But I admit I’m not as well versed.

I agree with @ROBERT BONNER comment about being mindful to discharge the capacitors before working around any of those components. Even trim work to run wires, many trim pieces hide airbag components.

 

[Mr Big]

Correct, I’m familiar with them, the goal of these propellents is to create nitrogen in fast and high volume, I’m not familiar with it used in any rocket propulsion, but seems possible.
My point is that while these do exist and serve a value, people should not assume they are riding around with live ammunition aimed at them or that it will in any way compromise their fuel tank. That’s not a true picture at all.
As for the smell, yes absolutely could smell similar.

No one said the ammunition is aimed at them. I'm just pointing out the possibility of one of these going off. The capsule that fired was 3 feet from my ear in an enclosed and relatively soundproof vehicle. Again, imagine going highway speeds and you experience this. A scenario might be that one might lose control of the vehicle. And I'm not assuming the possibility of one going off for no reason as I experienced it first-hand. However, Hyundai is recalling 239,000 cars for exploding seat belt parts is a good example of the possibility of damage or injury. I'm sure over the years they have improved but the possibility is still there.

 

[LazSlate]

Air bags and belt pre-tensioners are passive. They do not receive PCM or data. They are triggered solely by dc current.
Typically in a car a short implies positive + has been shorted to ground since everything is typically grounded all the time and the circuit is controlled by the + current. I am not 100% but I believe air bags and tensioners have both disconnected (+/-) as the computer measures resistance in the circuit to determine if the air bag/tensioner is in spec/working and a connection to ground would interfere with this reading.

For this to go off and short it would mean it got dc ground and then + shorted to another + maybe through worn insulation, etc.
Just seems strange for something to short like that. I would suspect the short occurred in a PCB board or something where the tolerances are much closer.

BTW seat belt tensioners have been around since 1981 and they even pre-date the mass usage of air bags.

 

[Mr Big]

I am not arguing the smell of the resulting explosion, your comment “12 to 16 on board explosive devices that use gun powder.” is not accurate, they don’t use gunpowder or smokeless powder, they use guanidinium nitrate. While there may be some loose commonalities, they are not the same thing.

2 service managers told me that most newer vehicles have 12 to 16 on board explosive devices used to fill airbags, curtains and activate the seatbelt tensioner. So, I researched as well as called Ford Motor Company, who is aware of the incident. They confirmed what was told to me, not to mention the dozens of articles and videos on the subject. Most manufacturers switched to these because of the unreliability of compressors and air tanks, especially when they age.

I’m not sure that’s how it works. I’m a bit outside my depth but the computer needs a reading not just a “short” to tell it how to react. For example, why did only the seatbelt go off then and not the airbag? If the short sent a “collision” reading wouldn’t both be triggered? If not then I’m assuming the short sent a specific signal that implied it was enough for the seatbelt but only driver side and not enough for the airbag? More likely the short simply triggered the charge directly to the pretensioner, bypassing the computer all together. But I admit I’m not as well versed.

How it usually works is a malfunction generates a signal through a module to the processor that determines the malfunction. Usually a light will come on, which did, after the detonation of the charge (Restraint Indicator Warning Light - The restraints control module has detected a fault with the driver seatbelt retractor pretensioner circuit). I asked the service manager the same question "Why didn't an airbag go off as well, if it thought it detected an accident" He explained the reason why only the seatbelt tensioner discharged is because of a short in the wiring going to the tensioner from the airbag module under the center console. I think your last sentence is spot on because there was no warning light until after it happened.

 

[Mr Big]

Air bags and belt pre-tensioners are passive. They do not receive PCM or data. They are triggered solely by dc current.
Typically in a car a short implies positive + has been shorted to ground since everything is typically grounded all the time and the circuit is controlled by the + current. I am not 100% but I believe air bags and tensioners have both disconnected (+/-) as the computer measures resistance in the circuit to determine if the air bag/tensioner is in spec/working and a connection to ground would interfere with this reading.

For this to go off and short it would mean it got dc ground and then + shorted to another + maybe through worn insulation, etc.
Just seems strange for something to short like that. I would suspect the short occurred in a PCB board or something where the tolerances are much closer.

BTW seat belt tensioners have been around since 1981 and they even pre-date the mass usage of air bags.

I'm not sure but after the incident I did get the Restraint Indicator Warning Light and the error message on my phone: "The restraints control module has detected a fault with the driver seatbelt retractor pretensioner circuit". So there is communication going on through the PCM.

I was told by Ford, and it shows on the invoice it was a wire near the airbag control module that was pinched from the factory, that finally wore through and cause a 2.4 or close voltage leak which triggered the seatbelt pretensioner charge.

Yes, they have and have changed their design many times since then. they used to use a spring and lever system with solenoid. But they proved to be too slow. After going through several modifications, they are what they are today and are still being tested and modified.

 

[sjwhiteley]

I can’t imagine this is a common occurrence, though, and don’t think it’s a cause for alarm. Hopefully the incident was fully documented to determine if this is a ‘systemic’ fault, or an unusual situation in assembly. I’m sure the NHTSA take these reports seriously.

European vehicles even have literal explosive bolts at the rear of the hood on a lot of cars! As demand (?) for safety increases, so does the existence of such things. There appears to be a lot of airbags (driver, passenger, a pillar, b pillar, roof crossmembers, and on, and on) in this vehicle as well as the tensioners.

I’m sure this is a very disturbing incident for the OP, and for anyone to experience it.