Land vehicles – Wheeled – Attachment
Reexamination Certificate
2000-03-30
2001-09-11
Culbreth, Eric (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S236000, C280S242100
Reexamination Certificate
active
06286862
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to a method of controlling inflation of an airbag in a motor-vehicle accident protection device, in which a gas generator is activated in response to a firing signal and inflates the airbag in dependence on operating conditions, a temperature of the gas generator is measured at least indirectly and the inflation takes place in dependence on the temperature. The invention also relates to a motor-vehicle airbag accident protection device, including an airbag, and an inflating device for the airbag having a gas generator, a firing device for activating the gas generator, a control device for controlling the operation of the inflating device in dependence on temperature, and a temperature-measuring device with a measuring sensor for at least indirectly sensing the temperature of the gas generator to generate a firing signal for the firing device.
Airbag protection devices or so-called airbags are becoming increasingly popular in motor vehicles. The mass flow of gas necessary for filling the airbag is currently usually produced by burning a solid fuel, for example sodium azide, wherein the fuel is ignited by a primer or detonating composition. Alternatively, gas generators which contain a solid propellant charge within a gas chamber are used, in which gas is stored in the gas chamber under high pressure (hybrid generators). When the propellant charge is ignited, which may likewise take place electrically through the use of a primer, a hole is produced at a predetermined location on the gas chamber and the airbag is inflated through that hole.
The pressure level of the airbag is a decisive variable for the restraining effect. If the pressure level is too low, there is the risk that, in spite of the airbag, a vehicle occupant may hit a steering wheel, for example, and suffer injuries. If, however, the pressure level is too high, that may lead to injuries to small people, children or infants. The pressure level which the airbag reaches is consequently a critical variable.
In addition, it has been found that, at low temperatures, in accidents with great deceleration and in the case of large, heavy vehicle occupants not wearing seat belts, there is the risk of the airbag pressure not being adequate to prevent the occupant from crashing through onto parts of the dashboard. At very high temperatures and in the case of small, lightweight vehicle occupants not wearing seat belts, on the other hand, there is the risk of the occupant being injured by the airbag during its deployment.
European Patent Application EP 0 790 157A2, corresponding to U.S. Pat. No. 5,664,802, discloses a motor-vehicle airbag accident protection device including an airbag, an inflating device for the airbag with a gas generator, a firing device for activating the gas generator and a control device for generating a firing signal for the firing device. A temperature-measuring device with a measuring sensor for sensing a temperature of the gas generator is also provided.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method of controlling inflation of an airbag and an airbag accident prevention device, which overcome the hereinaforementioned disadvantages of the heretofore-known methods and devices of this general type and with which the risk of injury is further reduced.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method of controlling inflation of an airbag in a motor-vehicle accident protection device, which comprises sensing and determining a temperature of a gas generator at least indirectly with an integrated circuit; transmitting the determined temperature as a coded signal to a control unit; supplying a firing signal with the control unit; activating the gas generator in response to the firing signal; and inflating an airbag with the gas generator in dependence on the temperature.
With the objects of the invention in view, there is also provided a motor-vehicle airbag accident protection device, comprising an airbag; and an inflating device for said airbag, said inflating device including a gas generator, a firing device for activating said gas generator, a control device for controlling operation of said inflating device in dependence on temperature, a temperature-measuring device with a measuring sensor for at least indirectly sensing a temperature of said gas generator to generate a firing signal for said firing device, an integrated circuit associated with said measuring sensor for sensing the temperature of said gas generator, and a data line connected between said integrated circuit and said control device.
With the method and device according to the invention, a temperature of the gas generator which has a decisive influence on the gas development during burning of the fuel is measured and taken into account during inflation of the airbag. If the gas generator is suitably disposed, the temperature may be the ambient temperature. If the gas generator is disposed at a location of the vehicle where experience shows that the temperature is significantly different from the ambient temperature, the temperature of the gas generator directly, and if possible the temperature of the fuel, must be measured.
There are numerous possibilities for controlling the inflation in dependence on the temperature. For example, at low temperature the ignition may be triggered with less delay after an accident. Furthermore, the widest variety of airbags are used at different locations of the motor vehicle. If such airbags, overall, have a porous structure or are provided with outflow openings, the pressure produced in them depends on the mass flow of the gas flowing in. If this mass flow increases at high temperature, a temperature-independent pressure can nevertheless be achieved, for example by an inflow opening in the airbag being made smaller with increasing temperature, and vice versa.
The airbag may be inflated by a plurality of gas generators in series, so that a predetermined pressure profile which corresponds to a desired profile can be achieved by temperature-dependent and/or pressure-dependent choice of the firing of the individual gas generators.
In order to achieve a predetermined pressure in the airbag it is advantageous to activate a following gas generator at an increasingly earlier time with decreasing temperature, because of the slower gas generation with decreasing temperature, so that the temperature dependence of the gas flow is tendentially counteracted.
A reaction accelerator may be used both in temperature-dependent control and in pressure-dependent control of the operation of the gas generator.
There are numerous and varied possibilities for intervention in the airbag accident protection device by which a temperature dependence of the airbag pressure established on the basis of the temperature dependence of the burning of the gas-generating fuel and/or the gas pressure in a closed container can be counteracted. For example, outflow openings from the gas generator may be made larger with decreasing temperature or outflow openings from the airbag may be made smaller with decreasing temperature and/or the instants at which the individual gas generators are fired may be varied if a plurality of gas generators are used for an airbag.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method of controlling the inflation of an airbag and an airbag accident protection device, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodimen
Blank Thomas
Heitzer Günter
Zelger Christian
Culbreth Eric
Greenberg Laurence A.
Lerner Herbert L.
Siemens Aktiengesellschaft
Stemer Werner H.
LandOfFree
Method of controlling the inflation of an airbag and airbag... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of controlling the inflation of an airbag and airbag..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of controlling the inflation of an airbag and airbag... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2442726