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Old 31st December 2011, 09:38   #31
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

Quote:
Originally Posted by nitinbose View Post
This is the reason why I'd installed front parking sensors, so that any chance of collisions may be detected and whatever I can do to prevent may be done.
Nitin, can you clarify a bit more- how will the front parking sensors help to prevent an accident, when the car is not doing parking speed?
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Old 31st December 2011, 09:38   #32
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

Occupants must thank themselves for wearing seat belts. The rest is just speculation and what-ifs.

Especially frontal air bags would not have made much difference in this case - for all we know, all manufactures source the air bag parts from the same supplier and use the same configurations. Of course, chassis construction makes a lot of difference in how sensors react - and keeping a bull bar and expecting air bag sensors to do their job well is a bit too much to ask for.

Lot of SUV drivers think they can drive their tall cars as aggressively as sedans. Of all the types of accidents, a rollover accident typically is due to driver error and unfortunately very hard to protect the occupants (no rollover tests in NCAP, etc.) ESP would have helped to certain extent.

I am generally not a fan of Toyota. They charge a lot for their 'reliable' products by not giving any kit that can go wrong. Surprisingly it works for them. On the other side of the spectrum, we have the Germans who charge a lot by giving all the just-out-of-the-lab kit that we don't want/need

In this case, I don't think Toyota is at fault except that they should have given more kit for the Fortuner - it is just a fancier looking innova.
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Old 31st December 2011, 09:56   #33
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

First we install illegal, unsafe & aftermarket accessories like bull bars, which by the way is not recommended on a car with airbags, and then we talk about safety & flame the company???

Who knows, as bblost said, the bull bars maybe the reason that the airbags dint deploy.
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Old 31st December 2011, 10:02   #34
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

Quote:
Originally Posted by AvonA7 View Post
I am no expert, having said that, looking at the 2nd pics, if the front aig bags do not deploy, IMO, we are un-necessarily arguing on behalf of Toyota ! Sorry If I sound rude here.
@Avon: I don't think anyone is arguing on behalf of Toyota. Most people including myself are trying to make people understand how and when air bags will be deployed. It will work the same for any manufacturer. Air bag sensors cannot be made too sensitive that they will deploy at every minor fender bender. Hence they are kind of placed on the inside beyond the bumpers.

Forget we are discussing Toyota for a moment, this rule applies to all vehicles with front only airbags. As I mentioned earlier, my Scorpio manual has pictorials of when the airbag won't deploy and it very clearly mentions that it may not deploy in a roll over.

That being said, it was shameful of Toyota to delete ESP for the Indian version. Why should they value our lives any less than other developed markets? ESP may have prevented the roll over in the first place..
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Old 31st December 2011, 10:09   #35
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

You should not use Crash/Bull Guard on vehicles that have air bags installed. They could hamper crash sensors from being effective.
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Old 31st December 2011, 10:09   #36
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

I could not understand how after market fitment affect the airbag operation and secondly anybody who is in the verge of accident will try to avoid collision rather than hitting them head on to activate the airbags unless rare cases headon is unavoidable.
From the wikipedia:
"Unlike crash tests into barriers, real-world crashes typically occur at angles other than directly into the front of the vehicle, and the crash forces usually are not evenly distributed across the front of the vehicle. Consequently, the relative speed between a striking and struck vehicle required to deploy the airbag in a real-world crash can be much higher than an equivalent barrier crash. Because airbag sensors measure deceleration, vehicle speed is not a good indicator of whether an airbag should have deployed. Airbags can deploy due to the vehicle's undercarriage striking a low object protruding above the roadway due to the resulting deceleration"

There are no mechanical switches needs to be pressed to activated during collision. Using of after market bumpers cannot taken into discussion. ideal sensor will be three axis gyro sensor and can be easily detected when car rolls over or near bumber crashes

Regards,
Vijay

Last edited by vijaycool : 31st December 2011 at 10:18.
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Old 31st December 2011, 10:13   #37
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

Quote:
Originally Posted by Vid6639 View Post
You can't have the airbags blow up on every small impact. That's why they are not sensitive. The airbags will only deploy on severe frontal impact and the main purpose is to prevent the body from hitting the steering or front glass. Not to prevent any other injury.
Quote:
Originally Posted by 4x4addict View Post
I know an exactly opposite instance when my friends Hyundai Elantra skidded off the road and hit a mount of sand that was off-loaded from a lorry for construction. The car was hardly damaged from the impact but the sensors got triggered and he ended up having to change the dash and airbags, but only the bumper of the car was damaged.
Quote:
Originally Posted by swiftnfurious View Post
Edit:: In the second pic, the bumper seems to be pretty much in good shape - no dents. So we can safely assume that the air bags sensors were NOT activated. Seeing the damage to the A pillar triggered my thoughts on mounting air bags on A pillar or air bags getting deployed on A pillar impacts.
From what 4X4addict has mentioned air bags can deploy with minor impacts also, not necessarily only with severe impacts. But even if front airbags deploy only when the bumper is severely damaged, then how is this "damage" defined? The bumper itself cracking and/or it coming off? In this case, the bumper came off on the RHS (may not be clear in the pics), so despite the bull bar (which I personally simply hate in any vehicle) the bumper did have an impact.
Personally, I feel that manufactures must put some sensors around the dash or the base of the A pillar so that in such impacts the front air bags deploy. Here the severity impact can not be nullified to only the rolling of the vehicle. The front wheel, fender and A pillar took the most major hit.
Most fortunate thing was all occupants using seat belts.
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Old 31st December 2011, 10:22   #38
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

Quote:
Originally Posted by wanderer4x4 View Post
From what 4X4addict has mentioned air bags can deploy with minor impacts also, not necessarily only with severe impacts. But even if front airbags deploy only when the bumper is severely damaged, then how is this "damage" defined? The bumper itself cracking and/or it coming off? In this case, the bumper came off on the RHS (may not be clear in the pics), so despite the bull bar (which I personally simply hate in any vehicle) the bumper did have an impact.
Personally, I feel that manufactures must put some sensors around the dash or the base of the A pillar so that in such impacts the front air bags deploy. Here the severity impact can not be nullified to only the rolling of the vehicle. The front wheel, fender and A pillar took the most major hit.
Most fortunate thing was all occupants using seat belts.
Did the elantra have a bull bar as well? In case of the Elantra the bumper took the full force of the impact and resulted in crumple zone deformation whereas in your case the bull bar took the impact and the bumper damage was superficial.

Like I said airbags not deploying is a good thing and not a bad thing. Airbags are known as SRS i.e. secondary restraint systems.

If you read the manual of your car you will also see airbags can deploy if you go over a speed breaker too fast and the front hits the hump or when you hit a curb by mistake at speed. The manual clearly mentions that under some circumstances the airbags may deploy.

Like I mentioned in my earlier post as well, airbags will deploy when there is severe frontal impact to prevent the driver from slamming against the steering or front glass.

The bumper has no part to play. The airbags will not get activated if the bumper even gets ripped off. The sensors are usually located around the crumple zone and activate when there is a deformation of the Front crumple zone.
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Old 31st December 2011, 10:27   #39
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

Here is a quote on How Airbags trigger from Wikipedia:
Quote:
Triggering conditions

Airbags are designed to deploy in frontal and near-frontal collisions more severe than a threshold defined by the regulations governing vehicle construction in whatever particular market the vehicle is intended for: U.S. regulations require deployment in crashes at least equivalent in deceleration to a 23 km/h (14 mph) barrier collision, or similarly, striking a parked car of similar size across the full front of each vehicle at about twice the speed.[36] International regulations are performance based, rather than technology-based, so airbag deployment threshold is a function of overall vehicle design.

Unlike crash tests into barriers, real-world crashes typically occur at angles other than directly into the front of the vehicle, and the crash forces usually are not evenly distributed across the front of the vehicle. Consequently, the relative speed between a striking and struck vehicle required to deploy the airbag in a real-world crash can be much higher than an equivalent barrier crash. Because airbag sensors measure deceleration, vehicle speed is not a good indicator of whether an airbag should have deployed. Airbags can deploy due to the vehicle's undercarriage striking a low object protruding above the roadway due to the resulting deceleration.

The airbag sensor is a MEMS accelerometer, which is a small integrated circuit with integrated micro mechanical elements. The microscopic mechanical element moves in response to rapid deceleration, and this motion causes a change in capacitance, which is detected by the electronics on the chip that then sends a signal to fire the airbag. The most common MEMS accelerometer in use is the ADXL-50 by Analog Devices, but there are other MEMS manufacturers as well.

Initial attempts using mercury switches did not work well. Before MEMS, the primary system used to deploy airbags was called a "rolamite". A rolamite is a mechanical device, consisting of a roller suspended within a tensioned band. As a result of the particular geometry and material properties used, the roller is free to translate with little friction or hysteresis. This device was developed at Sandia National Laboratories. The rolamite, and similar macro-mechanical devices were used in airbags until the mid-1990s when they were universally replaced with MEMS.

Nearly all airbags are designed to automatically deploy in the event of a vehicle fire when temperatures reach 150-200 C (300-400 F).[37] This safety feature, often termed auto-ignition, helps to ensure that such temperatures do not cause an explosion of the entire airbag module.

Today, airbag triggering algorithms are becoming much more complex. They try to reduce unnecessary deployments and to adapt the deployment speed to the crash conditions. The algorithms are considered valuable intellectual property. Experimental algorithms may take into account such factors as the weight of the occupant, the seat location, seatbelt use, and even attempt to determine if a baby seat is present.
SOURCE

Last edited by .anshuman : 31st December 2011 at 10:30.
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Old 31st December 2011, 10:39   #40
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

Quote:
Originally Posted by Vid6639 View Post
The bumper has no part to play. The airbags will not get activated if the bumper even gets ripped off. The sensors are usually located around the crumple zone and activate when there is a deformation of the Front crumple zone.
So, does not the fender area constitute part of the front crumple zone? Here this area is completely damaged.

My confusion is that there may be instances where no real danger to the passenger cabin is there, yet air bags will deploy (as in case of hitting a curb or speedbreaker), but in case of slightly off centre impacts with major damage all around the driver the air bags do not deploy. So, my query is should manufacturers not provide some sensors around the dash, base of the A pillar region where the fender, door and A pillar meet just to provide protection in such cases. And I don't think these sensors would get activated with minor nicks and bumps so the question of over sensitivity will not arise. Or am I missing something here?

Last edited by wanderer4x4 : 31st December 2011 at 10:41.
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Old 31st December 2011, 10:48   #41
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

Quote:
Originally Posted by wanderer4x4 View Post
So, does not the fender area constitute part of the front crumple zone? Here this area is completely damaged.

My confusion is that there may be instances where no real danger to the passenger cabin is there, yet air bags will deploy (as in case of hitting a curb or speedbreaker), but in case of slightly off centre impacts with major damage all around the driver the air bags do not deploy. So, my query is should manufacturers not provide some sensors around the dash, base of the A pillar region where the fender, door and A pillar meet just to provide protection in such cases. And I don't think these sensors would get activated with minor nicks and bumps so the question of over sensitivity will not arise. Or am I missing something here?
Front fender only has sheet metal damage caused by a rollover. It is not damage due to sudden frontal impact or sudden deceleration. You car has damage only to the outer sheet metal and not to the frame. Moreover like you mentioned the car only glanced a tree then rolled over.

The A pillar and front fender will have sensors if the car had side curtain airbags. The Fortuner does not have this. In a rollover i.e. sideways what's the point of having the front airbags deploy? You need side airbags for that.
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Old 31st December 2011, 10:52   #42
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

If NCAP standards includes 45 deg collision for deployment of front airbags we can see lots of cars failing the test unless 3 axis gyro sensor is deployed. Also I have heard manufactures reduce the sensitivity of the sensors for Indian traffic condition not to deploy airbags during small accident. Manufacturers have the intention that buyer(especially India) will crib for the high cost of replacement console. If they really reduce the sensitivity there is no need of airbag which doesnot work. I will prefer with ABS only.

Regards,
Vijay

Last edited by vijaycool : 31st December 2011 at 11:00.
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Old 31st December 2011, 11:04   #43
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

Quote:
Originally Posted by wanderer4x4 View Post
The vehicle skidded under braking
Thank God that there was no major injury. I don't get one thing "skidded under braking"? Is not Fortuner fitted with ABS?

Though .anshuman mentioned that Fortuner doesn't have ESP but is not ABS alone sufficient to prevent skidding?
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Old 31st December 2011, 11:09   #44
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

I think effectiveness of ABS is also relative to speed. Here, the curve around a small hillock must have been taken at a high speed that was more than what the vehicle was capable of handling, and so ABS or not it would have gone out of control.
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Old 31st December 2011, 11:40   #45
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Default re: Toyota Fortuner crashes, Air bags did not deploy *EDIT* Another similar case Pg.7

Quote:
Originally Posted by vb-san View Post
Nitin, can you clarify a bit more- how will the front parking sensors help to prevent an accident, when the car is not doing parking speed?

It would definitely not prevent a crash but if you move too close to an object, you'd get a distance warning indicating your approach to the obstacle. I'm sure a crash guard serves a similar purpose.
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