Talk:Airbag
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[edit] Old talk
206.188's recent edit added "The airbag sensor is a MEMS acelerometer, which is a small integrated circuit chip with integrated micromechanical elements." I believe that this is true, however I also believe that airbags initially used mercury switches or something like that instead. Does anyone know what the historical technologies were? Bryan 01:07, 4 Feb 2004 (UTC)
Bryan, There was some work initially in Mercury switches but they did not work very well. Before MEMS, the primary system used to deploy airbags was called a "rolamite". A rolamite is an interesting contraption that was originally developed to detect launch of inter continental ballistic missiles. This device was developed at Sandia National Laboratories. The rolamite and similar macro-mechanical devices were used in air bags until the mid-1990's. Now 100% of cars use MEMS devices. Mostly, the ADXL-50 by analog devices, but there are other MEMS manufacturers as well. Paul paul.mcwhorter@memx.com
- Thanks! I'll add that to the article tonight, if nobody beats me to it. :) Bryan 16:27, 6 Feb 2004 (UTC)
[edit] crash speed and energy
"Roughly speaking, a 14 mi/h (23 km/h) barrier collision is equivalent to striking a parked car of similar size across the full front of each vehicle at about 28 mi/h "
Is this correct, since the kinetic energy of a car going 28 is 4 times that of one going 14 (not twice as much)? Bubba73 16:12, 19 Jun 2005 (UTC)
Yes. Assuming equal mass cars and a fully inelastic collision, a quarter of the energy is left after the crash in motion of each car (each is now going 14 mph), and a quarter is absorbed by each car -- so the same energy is absorbed by the car as if it hit a wall at 14 mph. This can be derived from conservation of momentum + energy + an assumption of inelasticity. Evand 04:43, 20 Jun 2005 (UTC)
[edit] second edition airbags
I was just wondering if anyone knew what second edition airbags mean. I have a sticker in my window with this on it and I was wondering does this mean that my vehichal has been in an accident and the airbags have been replaced or was there some sort of a recall on the first ones that were in it or is this just a name brand.
Second generation airbags are what I assume you are referring to. Most manufacturers refined their air bag designs in the late '90s to deploy at slower speeds and/or to have a two stage function that would deploy one or two charges depending on the circcustances of the impact.
[edit] Speed of airbag deployment
A few months ago, I needed to compare the speed of something to the speed of an airbag. I cited the 1/20 second (or 50 milliseconds) data in Wikipedia. Another engineer pointed out that 50 milliseconds seemed much too long for an airbag to deploy. We ran a few what if scenarios mathematically.....and 50 milliseconds seemed to be too long.
I did some more research on the Internet and found 3 other sources besides Wikipedia (1 was a U.S. Patent Application, another was a National Highway Safety Department presentation on airbags), and all 3 sources said 15 milliseconds is typical for high speed crashes and 25 milliseconds is typical for low speed crashes.
I edited the Wikipedia article today to change the 1/20 second deploy time to the 15 and 25 millisecond data referenced above. I am not an automotive airbag engineer, but when 3 other sources say it is faster than 1/20 second, or 50 milliseconds.......and basic physics also says it must be less than 50 milliseconds....I tend to believe the 15 and 25 millisecond data.
Dale Maley Dmaley@route24.net
[edit] hot air
I've seen GM engineer John Hetrick cred with inventing the airbag in '52. I've also seen stats saying airbags only reduce fatalities in those wearing seatbelts by 8%. (Unfortunatetly, I can't cite sources for either...) Anybody able to confirm & include? Trekphiler 18:53, 4 January 2006 (UTC)
[edit] Responce time
What's the aribag average responce time? A friend of mine couldn't find this info here :( He later told me it's about 0,03-0,05s but citations here would be great.--Piotr Konieczny aka Prokonsul Piotrus Talk 16:15, 17 January 2006 (UTC)
[edit] Side airbags
Side airbags have been around way before 1998, as previously stated by the article. The 1996 Mercedes E-Class, for example, had side airbags. I am therefore deleting references to the 1998 Volvo S80 since by this time, side airbags were well and truly common place. Davez621 09:39, 13 March 2006 (UTC)
[edit] Spelling
Well, sometimes it's spelled "air bag" and sometimes "airbag", should this be unified? Acdx (talk | contribs) 10:08, 5 June 2006 (UTC)
[edit] Airbag Fatalities
I removed this:
"In Europe the number of people not wearing their seatbelts is very small when compared to the US, and Europeans are less likely to be obese. As a direct result of these two points, European airbags are less powerful than their American counterparts and are therefore less likely to cause loss of life than those fitted to American cars."
Give me a break. If you want to reintroduce this, please provide citations for every claim made in the paragraph. kdogg36 01:57, 27 July 2006 (UTC)
Agreed. I've heard the exact opposite regarding airbag deployment strength, in fact--that American-market cars have less forceful airbags because the occupants are more likely not to be wearing their seat belt, whereas in Europe the airbags can deploy faster (more forcefully) because it's assume you're wearing a seatbelt. --69.242.193.68 02:01, 1 August 2006 (UTC) KeplerNiko
[edit] Dates of Deployment
I take strong issue with the discussion of the dates of airbags first being used in vehicles, especially since it seems to me that it violates Wikipedia:Neutral point of view. It seems to me that this article is American-car biased, a country whose automobile manufacturers are most assuredly not first when I think of those who were first-adopters of new safety technology.
Particularly, the line about Chrysler making airbags "standard equipment across its entire line in 1990" makes it sound like Chrysler was the first manufacturer to standardize airbag installation. The next paragraph indicates, however, that US cars produced after 1 April 1989 must have either airbags or automatic seat belts (latter is news to me)--it seems to me that the vast majority of manufacturers opted to install airbags over seat belt systems. However, the way the article is written, it seems like Chrysler's actions were unique and, most of all, done out of its own initiative, rather than being federally mandated.
Quite simply, Chrysler was neither the only company to take this step, nor did it have a choice in the matter. I think the line implying Chrysler did something innovative should be stricken. --69.242.193.68 02:17, 1 August 2006 (UTC) KeplerNiko
[edit] 1970's Implication
The US experiment in the early 1970's ended pretty quickly as I recall. Does the article mean to imply that this was ongoing? PLawrence99cx 05:42, 4 October 2006 (UTC)
