Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
1998-12-31
2001-01-30
Louis-Jacques, Jacques H. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C701S046000, C280S735000, C180S271000, C180S282000, C340S436000, C340S669000, C307S010100
Reexamination Certificate
active
06181998
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to start control of a passenger protection system and, more particularly, to an improvement in start control of a two-stage passenger protection system which has two inflators and is constructed to fire them in order under predetermined conditions.
2. Description of the Related Art
In the prior art, in the passenger protection system which is represented by the air bag system, for example, such an air bag system that inflates an air bag at a time when a impact acceleration in excess of a predetermined reference is detected has been the mainstream. However, according to various later studies, experiments, etc., it becomes apparent that in some cases it is not always proper for the passenger protection to inflate the air bag at a stretch.
In recent years, various two-stage air bag systems have been proposed from a viewpoint of passenger protection (for example, see Patent Application Publication (KOKAI) Hei 2-310143, etc.). In such two-stage air bag systems, a first stage inflator is fired under predetermined conditions to inflate the air bag until a predetermined size, and then a second stage inflator is fired to inflate the air bag up to its maximum at a point of time when second predetermined conditions are satisfied.
In such two-stage air bag systems, it becomes an issue from a viewpoint of proper passenger protection how the first stage inflator and the second stage inflator should be fired.
As a relatively simple method of firing the inflators, for example, the start control can be thought of such that a deceleration caused in a crash is measured so as to calculate its integral value and then the first stage inflator and the second stage inflator are fired respectively when such integral value exceeds respective threshold values.
Such start control can be employed enoughly enoughly in practical use unless so-called stagnation of the integral value of the deceleration is caused between the fire of the first stage inflator and fire of the second stage inflator.
However, according to the type of the crash, sometimes such a phenomenon is produced that, since increase in the integral value of the deceleration becomes small, i.e., a stagnation state is generated after the first stage inflator has been fired, the integral value of the deceleration hardly exceeds the threshold value to generate firing of the second stage inflator, although fire of the second stage inflator is requested. For example, in the case of the so-called offset crash, because a part of constituent parts of the vehicle is damaged by the impact, sometimes the integral value of the deceleration is stagnated after the first stage inflator has been fired. In the above type of crash, the case is sometimes caused where, only if fire of the inflators is determined based on the decision whether or not the integral value of the deceleration exceeds the threshold value being set under aforementioned simple conditions, the second stage inflator cannot be fired in a period of time when fire of the second stage inflator is truly needed.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a start controlling method for a passenger protection system and a start controlling system for a passenger protection system both capable of executing start control of the passenger protection system which has two-stage inflator appropriately, and a recording medium for recording a start controlling program for the passenger protection system.
It is another object of the present invention to provide a start controlling method for a passenger protection system and a start controlling system for a passenger protection system both capable of firing a second inflator without fail if a crash needing to start fire of the second inflator occurs after a first inflator has been fired even under the situation that so-called stagnation of a time integral value of deceleration is caused, and a recording medium for recording a start controlling program for the passenger protection system.
In order to achieve the object of the present invention, according to a first aspect of the present invention, there is provided a start controlling method for a passenger protection system, for controlling start of the passenger protection system which has a first inflator and a second inflator and is constructed such that a protection system for protecting passengers of a vehicle is started by firing the first inflator and the second inflator respectively in response to a start signal from an external device, the method comprising the steps of:
detecting a deceleration of a vehicle;
calculating a speed integral value which is time integration of the deceleration;
deciding whether or not the speed integral value exceeds a first predetermined threshold value, and then starting the first inflator if it has been decided that the speed integral value exceeds the first predetermined threshold value;
comparing a detected deceleration of the vehicle with a previously stored predetermined deceleration for a first predetermined time after the first inflator has been started, then deciding whether or not the detected deceleration of the vehicle exceeds the previously stored predetermined deceleration to increase speed reduction, and then executing time integration over an area, in which the detected deceleration of the vehicle exceeds the previously stored predetermined deceleration, for a second predetermined time if it has been decided that the detected deceleration of the vehicle exceeds the previously stored predetermined deceleration to increase the speed reduction;
adding the time integral value to a speed integral value which is calculated as time integration of the detected deceleration of the vehicle until a point of time when it has been decided that the detected deceleration of the vehicle exceeds the previously stored predetermined deceleration to increase the speed reduction; and
deciding whether or not an added result exceeds a second predetermined threshold value, and then executing start of the second inflator if it has been decided that the added result exceeds the second predetermined threshold value.
Such start controlling method has been made in view of the fact that, if increase of the speed integral value becomes slow, i.e., stagnation of the speed integral value is caused, after the first inflator has been fired but the deceleration in excess of a predetermined value is caused, fire of the second inflator must be needed.
More particularly, in various types of crashes which needs firing of the first inflator but does not need fire of the second inflator, data of change in the deceleration caused when the deceleration is increased up to its maximum (in other words, the acceleration is increased to the negative side) are collected previously according to the experiment, etc., and stored, and then the detected deceleration of the vehicle is compared with the stored deceleration after the first inflator has been fired. Then, if the detected deceleration of the vehicle exceeds the stored deceleration so as to increase speed reduction, time integration is carried out over an area, in which the detected deceleration of the vehicle exceeds the stored deceleration so as to increase speed reduction, until the desired fire time of the second inflator. Then, the integrated value is added to the speed integral value calculated at a point of time when it has been decided that the detected deceleration of the vehicle exceeds the stored deceleration so as to increase speed reduction. Then, when the added result exceeds a predetermined threshold value, start of the second inflator is executed. As a result, even if the stagnation of the speed integral value is caused, the second inflator can be fired without fail.
In order to achieve the object of the present invention, according to a second aspect of the present invention, there is provided a start controlling system for a passenger protection system, for controlling start of the passenger protection system whi
Kanameda Yasumasa
Miyaguchi Koichi
Airbag Systems Co., Ltd.
Louis-Jacques Jacques H.
Wenderoth Lind & Ponack, LLP.
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