Electrical transmission or interconnection systems – Vehicle mounted systems – Automobile
Reexamination Certificate
2000-03-28
2002-08-27
Sterrett, Jeffrey (Department: 2838)
Electrical transmission or interconnection systems
Vehicle mounted systems
Automobile
C180S274000, C280S735000, C340S436000
Reexamination Certificate
active
06441511
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
In general, the present invention relates to an air-bag control apparatus provided for controlling an air-bag unit. More particularly, the present invention relates to an air-bag control apparatus that is hardly affected by noise introduced onto a line transmitting a signal the driving air-bag unit, thereby being capable of avoiding a malfunction of the air-bag unit. Description of the Related Art
In recent years, there are an increasing number of cars in each of which an air-bag unit is provided on a steering wheel to protect the passengers against a shock caused by a car collision in the event of an accident.
FIG. 7
is an explanatory diagram showing the configuration of an embodiment implementing the conventional air-bag control apparatus. As shown in the figure, on the column side, there are provided an air-bag sensor
61
for detecting a collision of the car, a carrier generation means
62
for generating a carrier, a modulation circuit
63
for modulating the carrier and a transmission circuit
64
for transmitting a modulated carrier to the steering-wheel side. On the steering-wheel side, on the other hand, there are provided a reception circuit
65
, a demodulation circuit
66
and an air-bag driving control circuit
67
.
Next, the operation of the embodiment implementing the conventional air-bag control apparatus is explained by referring to
FIGS. 7 and 8
. The carrier generation means
62
on the column side generates typically a sinusoidal carrier like one shown in diagram A of
FIG. 8
at normal times. This carrier is supplied to the modulation circuit
63
which is typically a balanced modulation circuit. At normal times, however, the modulation circuit
63
does not output a modulated carrier. Only when a modulation signal is supplied to the modulation circuit
63
does the modulation circuit
63
output a modulated carrier. Assume that the air-bag sensor
61
detects a car collision at a point of time t
0
. In this case, the air-bag sensor
61
generates a predetermined voltage E as shown in diagram B of FIG.
8
. The voltage E serves as a modulation signal supplied to the modulation circuit
63
. As a result, the modulation circuit
63
modulates the carrier supplied thereto by the carrier generation circuit
62
starting from the point of time to as shown in diagram C of FIG.
8
and outputs a modulated carrier to the transmission circuit
64
. The transmission circuit
64
transmits the modulated carrier received from the modulation circuit
63
to the reception circuit
65
. A signal is transmitted from the transmission circuit
64
to the reception circuit
65
through typically a non-contact coupling means (or a non-contact coupler not shown in the figure). The reception circuit
65
passes on the modulated carrier received from the transmission circuit
64
to the demodulation circuit
66
. The demodulation circuit
66
demodulates the modulated carrier received from the reception circuit
65
to produce a predetermined voltage E′ shown in diagram D of
FIG. 8
as a demodulated signal which is supplied to the air-bag driving control circuit
67
. The air-bag driving control circuit
67
drives the air-bag unit in accordance with the demodulated signal.
Additionally, in recent years, there are many other pieces of electronic equipment installed in a car. The other electronic equipment generate and radiate a variety of electromagnetic waves and. An electromagnetic wave generated by the other electronic equipment may be introduced onto a transmission line between, for example, the modulation circuit
63
and the demodulation circuit
66
in the configuration of the conventional embodiment in spite of the fact that the car does not collide with anything and, hence, the air-bag sensor
61
does not generate the predetermined voltage E. When such an electromagnetic wave is introduced onto the transmission line, a noise signal like one shown in diagram E of
FIG. 8
is supplied to the demodulation circuit
66
which then demodulates to inadvertently generate a demodulated signal like one shown in diagram F of FIG.
8
. The demodulated signal is supplied to the air-bag driving control circuit
67
. When this happens, the air-bag driving control circuit
67
inadvertently drives the air-bag unit in accordance with the demodulated signal generated by the demodulation circuit
66
in spite of the fact that the demodulated signal originates from an introduced noise signal.
When the air-bag unit is driven in spite of the fact that no accident such as a car collision takes place, the driver's field of vision is blocked and driving is disturbed.
SUMMARY OF THE INVENTION
It is thus an object of the present invention to avoid a malfunction of an air-bag unit caused by an electromagnetic wave generated by various kinds of electronic equipment.
According to a first aspect of the present invention, there is provided an air-bag control apparatus: wherein first modulation means modulates a first carrier in accordance with a signal having a predetermined pattern from signal generation means to generate a first modulated signal and supply it to first demodulation means when collision detection means detects a car collision; the first demodulation means demodulates the first modulated signal to produce a first demodulated signal and supply it to signal comparison means; and the signal comparison means outputs an activation signal for activating an air bag only if the first demodulated signal matches the signal having the predetermined pattern.
According to a second aspect of the present invention, there is provided an air-bag control apparatus as in the first aspect, wherein the signal generation means comprises a plurality of switches for controlling car electronic equipment and a signal generation circuit for generating the signal having the predetermined pattern in accordance with an operating state of the switches.
According to a third aspect of the present invention, there is provided an air-bag control apparatus as in the second aspect, wherein the switches are installed on a steering wheel.
According to a fourth aspect of the present invention, there is provided an air-bag control apparatus as in the first, second or third aspect, wherein, the second modulation means modulates the second carrier in accordance with the signal having the predetermined pattern output from signal generation means to generate a second modulated signal and supply it to the second demodulation means; the second demodulation means demodulates the second modulated signal to produce a second signal; and the first modulation means modulates the first carrier in accordance with the second signal.
According to a fifth aspect of the present invention, there is provided an air-bag control apparatus as in the first aspect, wherein the signal generation means comprises a data retention unit for storing data having a predetermined format and a microcomputer, and the microcomputer reads out the data and generates the signal having the predetermined pattern.
According to a sixth aspect of the present invention, there is provided an air-bag control apparatus as in the fifth aspect, wherein two data retention units and two microcomputers are provided, and one of the data retention units and one of the microcomputers are provided on a column side, and one of the data retention units and one of the microcomputers are provided on a steering-wheel side.
REFERENCES:
patent: 5636863 (1997-06-01), Reid et al.
patent: 5934704 (1999-08-01), Hansen et al.
patent: 5977653 (1999-11-01), Schmid et al.
patent: 6012736 (2000-01-01), Hansen et al.
patent: 6020655 (2000-02-01), Heiner et al.
patent: 6121692 (2000-09-01), Michaels et al.
patent: 195 41 998 (1997-05-01), None
patent: 198 29 730 (2000-01-01), None
patent: 0 482 234 (1992-04-01), None
LandOfFree
Air-bag control apparatus for avoiding air bag unit... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Air-bag control apparatus for avoiding air bag unit..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Air-bag control apparatus for avoiding air bag unit... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2888809