Land vehicles – Wheeled – Attachment
Reexamination Certificate
1998-11-20
2001-02-13
Rice, Kenneth R. (Department: 3611)
Land vehicles
Wheeled
Attachment
C701S045000
Reexamination Certificate
active
06186539
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus and method for controlling an actuatable occupant restraint device for a vehicle. More particularly, the present invention relates to a method and apparatus for controlling an actuatable occupant restraint device having a plurality of actuatable stages.
BACKGROUND OF THE INVENTION
Actuatable occupant restraint systems, such as air bags, for vehicles are well known in the art. Such restraint systems include one or more collision sensing devices for sensing vehicle crash acceleration (vehicle deceleration). Air bag restraint systems further include an electrically actuatable igniter, referred to as a squib. When the collision sensing device senses a deployment crash event, an electrical current of sufficient magnitude and duration is passed through the squib to ignite the squib. When ignited, the squib initiates the flow of inflation fluid into an air bag from a source of inflation fluid, as is known in the art.
Certain known collision sensing devices used in actuatable occupant restraint systems are mechanical in nature. Still other known actuatable occupant restraint systems for vehicles include an electrical transducer, such as an accelerometer, for sensing vehicle crash acceleration. Systems using an accelerometer as a crash or collision sensor further include some circuitry, e.g., a controller, for monitoring the output of the accelerometer. The accelerometer provides an electrical signal having an electrical characteristic indicative of the vehicle's crash acceleration. The accelerometer is operatively connected to a controller, such as a microcomputer, which performs a crash algorithm on the acceleration signal for the purpose of discriminating between a deployment and a non-deployment crash event. When a deployment crash event is determined to be occurring, the restraint is actuated, e.g., an air bag is deployed.
One particular type of occupant restraint system known in the art is a multi-stage occupant restraint system that includes more than one actuatable stage associated with a single air bag. In a multi-stage air bag restraint system, air bag inflation is the result of the control of a multi-stage inflator. Such multi-stage air bag systems typically have two or more separate sources of inflation fluid controlled by actuation of associated squibs. Known control arrangements control the actuation of the multiple stages based on a timer function. A problem arises in monitoring for a beginning of the crash event to start the timer. False starts (and endings) could occur due to signals resulting from road noise.
U.S. Pat. No. 3,966,224 is directed to a multi-stage air bag restraint system having two squibs. Under certain types of crash conditions, a first stage is actuated followed by actuation of a second stage a predetermined time after actuation of the first stage. If the crash acceleration is greater than a predetermined level, both stages are simultaneously actuated.
U.S. Pat. No. 4,021,057 is directed to a multi-stage air bag restraint system having a plurality of firing elements for gas generators. Crash velocity is compared against a plurality of threshold values for control of the plurality of squibs and, in turn, control of the inflation rate of the air bag.
U.S. Pat. No. 5,400,487 is directed to an air bag restraint system having a plurality of separately controlled gas generators actuated at selected times in a selected order to control the air bag's inflation profile. The selective triggering is a function of both the crash type extrapolated from past received acceleration data and the occupant position based on received occupant position data.
U.S. Pat. No. 5,411,289 is directed to an air bag restraint system having a multiple level gas generating source. “The electronic control unit is responsive to a combination of sensed inputs from the temperature sensor, the seat belt sensor, and the acceleration sensor for determining both an optimum gas generation level and inflation sequence times for controlling the multiple level gas generation source.” (Abstract of '289 patent) Many types of crash algorithms for discriminating between deployment and non-deployment crash events are known in the art. Algorithms typically are adapted to detect particular types of crash events for particular vehicle platforms. One example of such an algorithm is taught in U.S. Pat. No. 5,587,906 to McIver et al. and assigned to TRW Inc.
Air bag restraint systems are also known to require more than one sensor for detection of a deployment crash event. Often, the plural sensors are arranged in a voting scheme in which all the sensors must “agree” that a deployment crash event is occurring before restraint actuation is initiated. In certain known arrangements having a first and second sensor, the second sensor is referred to as a “safing sensor.” Air bag actuation occurs only if the first sensor and the safing sensor indicate a deployment crash event is occurring.
It is desirable to discriminate certain types of crash events for vehicles having, what is known in the art as, “frame body” construction. Such vehicles include trucks and sport utility vehicles. In these types of vehicles, discrimination of certain types of crash events is difficult using single point crash sensing with the crash sensor is located at a position substantially in the center of the vehicle. One such crash event that is difficult to discriminate is one known as a “high speed bumper override.”
SUMMARY OF THE INVENTION
The present invention is directed to an apparatus for controlling an actuatable occupant restraint system for a vehicle, the restraining device having first and second actuatable stages. The apparatus comprises a crash sensor for sensing crash acceleration and providing a crash acceleration signal indicative thereof and an average crash acceleration determiner responsive to the crash acceleration signal for determining an average crash acceleration value and providing a signal indicative thereof. The apparatus further includes a controller operatively coupled to the first and second actuatable stages. The controller effects actuation of the first actuatable stage upon the determined average acceleration value exceeding a first threshold value. The controller determines a crash severity index having a value according to a time interval from when the determined average crash acceleration value exceeds the first threshold value to when the determined average crash acceleration value exceeds a second threshold value. The controller effects actuation of the second actuatable stage in response to the crash severity index value.
In accordance with another embodiment of the invention, an apparatus includes a central crash sensor located at a substantially central location of the vehicle for sensing crash acceleration during a vehicle crash condition and providing a first crash acceleration signal indicative thereof. Velocity determining means responsive to the first crash acceleration signal determines a crash velocity value from the first crash acceleration signal and provides a crash velocity signal indicative thereof. A crush zone sensor is located at a forward location of the vehicle so as to be subjected to crash acceleration relatively early during the vehicle crash condition. The crush zone sensor provides a second crash acceleration signal indicative of the sensed crash acceleration. The apparatus further includes control means coupled to the actuatable device, the central crash sensor, and the crush zone sensor for (i) effecting actuation of a first stage of an actuatable restraint when the determined crash velocity value exceeds a first threshold value, (ii) effecting actuation of the first of the actuatable stages when a value functionally related to the crash acceleration value from the crush zone sensor exceeds a second threshold value, (iii) upon the determined crash velocity value exceeding a third threshold value, determining a first crash severity index having a value related to a time interval from when the
Chiang Wei-Te
Foo Chek-Peng (Anson)
Shields Anne Marie
Weiss Kevin D.
Yeh Huahn-Fern (Jeff)
Rice Kenneth R.
Tarolli, Sundheim, Covell Tummino & Szabo L.L.P.
TRW Inc.
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