Airbags failed to deploy! How common?

[thescreensavers]

Air bag systems are very complex, we do not have enough information here to decide if it should have blown or not but after the fact maybe it should have.

A crash investigator that can read the airbag computer might be able to answer these questions.

 

[wemay]

Air bag systems are very complex, we do not have enough information here to decide if it should have blown or not but after the fact maybe it should have.

A crash investigator that can read the airbag computer might be able to answer these questions.

This^

 

[michaelluscher]

If my sister is anything, she's consistent

Neither of these crashes deployed airbags
Maybe the Taurus would've blown the side airbags, but it wasn't optioned with them
The Taurus did fire seatbelt pretensioners tho

We're at the mercy of the all knowing SRS module
Barring shady half rigged collision repair

 

[KrisZ]

Before making snide comments about your perceptions about what other people do or do not know, I would suggest the following:

1) Learn about how an accelerometer works. We're looking for X/Y axis (lateral and longitudinal) here.

2) Visualize a vehicle impaled by a vertical pole through its centre of gravity (somewhere in the neighbourhood of the centre console, between the hips of the seated front passengers for a passenger car). In your mind, spin that car around the pole - really, really violently even.

3) Reflect on what you learned about the accelerometer, and ask yourself what lateral acceleration would be registered.

4) Ask yourself: "Self, if I'm a system that decides when to deploy an airbag, and that decision is informed primarily by lateral acceleration, what decision would I make?"

5) If your answer is anything but "Nothing", revert to step 1.

LOL, nice hypothetical, but they also have the Z axis, and you conveniently omitted that. Or perhaps you need more googling.
Plus an airbag system doesn't rely only on an accelerometer. That would be one poorly designed system.

 

[fsdork]

LOL, nice hypothetical, but they also have the Z axis, and you conveniently omitted that. Or perhaps you need more googling.
Plus an airbag system doesn't rely only on an accelerometer. That would be one poorly designed system.

Can you cite an example of an airbag system which relies on Z-axis delta-v? I haven't come across one yet, so that would be really interesting.

Also, you seem to have misread the post you quoted. My use of the word "primarily" wasn't accidental.

 

[mk378]

NHTSA crash tests have considered side impact since the 1990s, and standards were tightened with improvements of side air bags. Originally it was only "T-bone" crashes where a moving simulated car hits the test car in the side. It has been expanded to the case of loss of control resulting in sliding sideways into a tree or pole.

 

[KrisZ]

Can you cite an example of an airbag system which relies on Z-axis delta-v? I haven't come across one yet, so that would be really interesting.

Also, you seem to have misread the post you quoted. My use of the word "primarily" wasn't accidental.

Here is one from Infineon. I’m sure not all system are the same, perhaps they use other methods or sensors to detect a rollover, but the Z axis needs to be monitored in one way, shape or form to have a full, comprehensive data on the G forces of in all directions.

 

[fsdork]

Here is one from Infineon. I’m sure not all system are the same, perhaps they use other methods or sensors to detect a rollover, but the Z axis needs to be monitored in one way, shape or form to have a full, comprehensive data on the G forces of in all directions.

View attachment 177313

I see the "z-" indication, but there's no explanation as to how it's used, or why.

 

[Exhaustgases]

Anyone else here the national news the other day, about the new airbag recall?

 

[97K15004WD]

I see the "z-" indication, but there's no explanation as to how it's used, or why.

There is a video showing a ford raptor jumping that sets off all the airbags. It bottomed out the suspension and all the bags went off. I'll look for it.

 

[Dave Sherman]

I was surprised when the wife's 2013 Equinox was totalled earlier this year; stepson rear-ended somebody at around 15 MPH. Hood was bent up, radiator was cracked, but airbags did not deploy.

 

[supton]

I remember that the early airbags were initial powered to "replace" seatbelts. Then people started dying, go figure, they were overpowered. I wonder if the latest and greatest cars, what now with large crumple zones, simply don't "need" to fire the airbags in order to get deacceleration rates low. Car looks like it was blown apart--but if the driver's head doesn't get whiplash, doesn't bonk their head off any surface--did the airbag really need to blow?

Multiple sensors are used, right? So if a front sensor registers "huge" acceleration (due to being first on scene in the crash), but the rear reports sedate deacceleration, then the airbag doesn't need to blow. But if the rear registers really high levels, indicating all of the car is above a threshold, then blow.

Crumple zones are great passive items. Airbags are active items that literally blow up. I don't follow any lawyer magazines but I have to wonder if the OEM's are having to deal with lawsuits from airbag related injuries, including simple burns. The more the car can passively reduce passenger acceleration rates, rather than actively (using the airbag), the better for the OEM (and passengers, not all of whom have an airbag, like the rear passengers).

 

[OVERKILL]

I remember that the early airbags were initial powered to "replace" seatbelts. Then people started dying, go figure, they were overpowered. I wonder if the latest and greatest cars, what now with large crumple zones, simply don't "need" to fire the airbags in order to get deacceleration rates low. Car looks like it was blown apart--but if the driver's head doesn't get whiplash, doesn't bonk their head off any surface--did the airbag really need to blow?

Multiple sensors are used, right? So if a front sensor registers "huge" acceleration (due to being first on scene in the crash), but the rear reports sedate deacceleration, then the airbag doesn't need to blow. But if the rear registers really high levels, indicating all of the car is above a threshold, then blow.

Crumple zones are great passive items. Airbags are active items that literally blow up. I don't follow any lawyer magazines but I have to wonder if the OEM's are having to deal with lawsuits from airbag related injuries, including simple burns. The more the car can passively reduce passenger acceleration rates, rather than actively (using the airbag), the better for the OEM (and passengers, not all of whom have an airbag, like the rear passengers).

My 2001 M5 had, IIRC, 12 SRS tags on the interior. Some companies get really wild with the airbags.
BMW:

 

[supton]

My 2001 M5 had, IIRC, 12 SRS tags on the interior. Some companies get really wild with the airbags.
BMW:
View attachment 177488

I guess the rear of the front seats could act like an airbag for rear occupants? hadn't thought of that, so maybe I'm off a bit on what I said.

But yeah, 12 sensors. One goes off the chart, have to wonder if it's just a failure of the sensor. But if it and its buddy go off the chart, and all are registering something, then something is happening. Lots of sensors. Good thing silicon is cheap now (I think they're all MEMS on silicon?).

link Tin foil hat time: stumbled across this while looking to see if MEMS in silicon was a thing:

A 2012 study found that voices can be detected by smartphone accelerometers in 93% of typical daily situations.

 

[edyvw]

I remember that the early airbags were initial powered to "replace" seatbelts. Then people started dying, go figure, they were overpowered. I wonder if the latest and greatest cars, what now with large crumple zones, simply don't "need" to fire the airbags in order to get deacceleration rates low. Car looks like it was blown apart--but if the driver's head doesn't get whiplash, doesn't bonk their head off any surface--did the airbag really need to blow?

Multiple sensors are used, right? So if a front sensor registers "huge" acceleration (due to being first on scene in the crash), but the rear reports sedate deacceleration, then the airbag doesn't need to blow. But if the rear registers really high levels, indicating all of the car is above a threshold, then blow.

Crumple zones are great passive items. Airbags are active items that literally blow up. I don't follow any lawyer magazines but I have to wonder if the OEM's are having to deal with lawsuits from airbag related injuries, including simple burns. The more the car can passively reduce passenger acceleration rates, rather than actively (using the airbag), the better for the OEM (and passengers, not all of whom have an airbag, like the rear passengers).

That is an issue, she banged her head pretty hard on B pillar. If the curtain dropped, it would not hit it.

 

[supton]

That is an issue, she banged her head pretty hard on B pillar. If the curtain dropped, it would not hit it.

That does sound like something is amiss, I missed that in the OP. Something does seem off here, be it a system failure or a programming failure.

 

[edyvw]

That does sound like something is amiss, I missed that in the OP. Something does seem off here, be it a system failure or a programming failure.

In addition, the rear seat, both seating surface and back, were crumpled and moved, as well as the floor at least 4 inches. This was the major impact, and the curtain would definitely prevent injuries in the back if someone was sitting.

 

[KCHOPS]

We were in a crash Monday night; hit by a speeding red light runner as we were turning left at a green arrow. No airbag deployment for us, either.

 

[KrisZ]

I’m starting to wonder that after the Takata airbag fiasco, manufacturers programmed the airbag deployment so that they don’t deploy as easily.

Are they rigging the tests, just like VW did with their diesel engines?

Here are some old 25mph crash tests, the all deploy the airbags

 

[dan_erickson]

Side airbags deploy on rollover. There is no sensor for being smashed in the side -which I believe is what your describing, unless it was so strong as to set off the G-force sensor - which would be far away in this case.

That is completely wrong. Side bags deployed all the time in a side impact.