Quote:
Originally Posted by Samba ...
Now my question is accidents can happen from any angle. I remember a case where an i20 hit a pole (Lamp post) and airbags were not deployed due to the very same reason. Same should occur in case of a side ways crash where the front bumper is not involved. So my basic query is why the manufacturers do not increase the number of sensors and put them in few more locations like the A pillar or some place which is higher than the front bumper ? Am just asking because of the pure lack of my knowledge. Is this because it will increase the car cost or there are any other reasons? |
The question is genuine. It all depends on the manufacturer where he places the sensors and how many they provide. Each assembly of airbags involves some serious engineering with estimation of motion of occupant in car during collision.
Now sensors could be mounted to A pillars and doors for detecting frontal-side or side collisions. During side collision, on rough estimation, the occupants would bang on to their side opposite to the direction of impact (inertia stuff). But if manufactures decide to omit curtain airbags (side) with sole reason of reducing costs, there won't be any use of deploying front airbags in most of the side collisions. Why omit such a safe feature ? Simply because side collisions are much less likely to happen than frontal collision.
Regarding vertical height of positioning of sensors, one might think what would be the need of height sensors since bumpers would be the first one to crash! Lets bring truck into the accident. What if one crashes into a truck from side or rear ? Yes, it would be a direct hit to A pillars for most of the cars, without touching bumper. So here comes the need of positioning sensors at height too!
But Indian Road Ministry had made it compulsory for all vehicles with lowest part of chassis having greater height than "X", should have steel bars installed below so that it reaches a height of "X" at least. I don't remember if it is also for sides of trucks but in US there is such rule for all directions.
So ideally there would be very rare cases in which frontal crash is caused with bumpers remaining undamaged. And IMO, this is the reason most (all maybe?) omit the heights more than height of bumper for locating sensors, useless costs. At sides of a vehicle there can be different scenario since all impacts from sides would impact almost at the same time at different heights.
Quote:
Originally Posted by vivekz ...
I also have similar question actually. I am assuming that the sensors are placed at some locations behind bumpers and other crash sensitive parts of the car. My query is on the trigger mechanism of these sensors.
Are they triggered only when they sense direct impact at locations covered by them or are they also triggered on rapid deceleration ( as what happens in accidents)
If it is latter, the case mentioned by Samba is interesting as even if the i20 crashed into a pole missing the sensor trigger points, the deceleration should have triggered the airbags. |
IMO, the logic takes both, direct impact as well as deceleration, having some different weightage to both . Do think of side collision where deceleration would not be much of value. Also frontal collision while stationary (head-on). So there is surely more stuff in the logic.
Anyone want to throw some light on it ?
There could be a number of reasons for undeployment of Airbags within my domain of knowledge.
1. Malfunction could not be ruled out
2. Sensor in region of hit, failed, or was not present at all and/or
3. Deceleration might not be the only factor besides the contact by sensors.
Quote:
Originally Posted by vivekz In the same light, is there also a difference in trigger mechanism in different classes of vehicles? For example, would a BMW have more number of sensors/ better sensing mechanism/ deceleration detection for airbag trigger than a more run of the mill hatch? Also talking about just front airbags, would the quality of protection offered by one in BMW would be different from one in Maruti (ignoring the car structure and build) |
Everyone must be aware, or now be aware, of Takata Airbags global recall. It has affected 100% of the big manufacturers globally. I think this might mean there is no/very little difference in "Airbags"
Now, regarding mechanisms, IMO, the basic mechanism is common. But there would be a major difference in the logic, sensor position, airbags position, timings, etc.
By comparing a Maruti with BMW I would prefer to say BMW might have better research and engineering in designing of SRS than Maruti but can't compare when we consider "Suzuki"