Measuring and testing – Speed – velocity – or acceleration
Patent
1996-06-24
1998-07-07
Dombroske, George M.
Measuring and testing
Speed, velocity, or acceleration
180282, 280735, 340436, 701 45, 701 70, B60R 2132
Patent
active
057772258
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a crash sensor suitable for sensing a crash of a vehicle and for being incorporated in a system for actuating a protective device such as an air bag provided for the safety of a vehicle occupant, and more particularly to a crash sensor capable to judge whether the protective device should be actuated or not in an intial stage of the crash.
BACKGROUND OF THE INVENTION
A most common type of a crash sensor applies a microcomputer for judging on a severity of a crash, wherein an acceleration signal outputted from an accelerometer is integrated with respect to time every time and then the time integrated value is compared with a prescribed reference value for judging the severity of a crash.
That is to say, the acceleration signal outputted from the accelerometer is integrated with respect to time as shown in FIG. 13 by areas provided with oblique and vertical lines. The protective device is actuated when the time integrated value has come up to the reference value V0 as shown in FIG. 14, while the protective device is not actuated as long as the time integrated value is smaller than the reference value V0 (as disclosed in U.S. Pat. No. 3,701,903 and Japanese Laid Open Patent Application No. 49-5501).
Dot-dash and solid curves in FIGS. 13 and 14 represent how the acceleration and the aforesaid time integrated value vary with time under the condition that oblique crashes occurs with high and intermediate speeds respectively. In order to insure the safety of a vehicle occupant, the protective device has to be actuated during the time T requiring an actuation of a protective device. In case of the oblique crash with high speed, the aforesaid time integrated value comes up to the reference value V0 at a time (tF) which falls within the time T requiring the actuation of the protective device, and the prior crash sensor actuates the protective device at an opportune moment. However, in case of the oblique with intermediate speed, the aforesaid time integrated value does not come up to the reference value V0 within the time T requiring actuation of the protective device, but comes up at a time tF' after a lapse of the time T requiring the actuation. This causes the prior crash sensor to actuate the protective device at an inopportune moment. Thus, in some types of the crash, the prior crash sensor unavoidably introduces a time delay into the system for actuating the protective device.
The prior crash sensor has another disadvantage that it is not capable of making a sharp distinction between the oblique crash occurring with intermediate speed and a head-on crash occurring with low speed during the time T requiring actuation of the protective device. The oblique crash with intermediate speed requires the actuation of the protective device while the head-on crash with low speed does not require the actuation of the protective device. This disadvantage is derived from the fact that the difference between the solid curve and a dashed curve in FIG. 14 is not very great in the initial stage of each crash.
There is another prior crash sensor wherein a displacement and a speed of an occupant's head are predicted on the basis of an acceleration signal output from an accelerometer so that an air bag may be sufficiently inflated before the occupant strikes against the air bag.
This crash sensor judges on the timing of actuation from such a predicted displacement as the occupant would travel in a vehicle during 30 milli-seconds after a crash occurred. The 30 milli-seconds which are the time required for inflating the airbag sufficiently.
This crash sensor also judges whether the air bag should be inflated or not from whether a secondary crash will injure the occupant As an energy of the secondary crash is determined by the speed of the occupant traveling in the vehicle at the moment of the secondary crash. So, this crash sensor judges on necessity of the actuating the air bag from such a predicted speed as the occupant would travel in the vehicle during 30 milli-seconds
REFERENCES:
patent: 4994972 (1991-02-01), Diller
patent: 5189311 (1993-02-01), Moriyama et al.
patent: 5225985 (1993-07-01), Okano
patent: 5389822 (1995-02-01), Hora et al.
patent: 5396424 (1995-03-01), Moriyama et al.
patent: 5497327 (1996-03-01), Takaya et al.
patent: 5506775 (1996-04-01), Tsurushima et al.
patent: 5508920 (1996-04-01), Gioutsos et al.
patent: 5544915 (1996-08-01), Fendt et al.
patent: 5608628 (1997-03-01), Drexler et al.
patent: 5629847 (1997-05-01), Shirakawa et al.
patent: 5631834 (1997-05-01), Tsurushima et al.
patent: 5638274 (1997-06-01), Konishi et al.
Moriyama Hiroshi
Sada Hiroyuki
Dombroske George M.
McCall Eric S.
Sensor Technology Co. Ltd.
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