VALVE CONTROLLED AUTOMOTIVE PYROTECHNIC SYSTEMS

Abstract: An adaptively controlled safety restraint system (20) is disclosed which includes a safety restraint device (22, 24) operative in response to a flow of pressurized gas, and fluid means (28) having a stored energy device (30) which can be activated to produce pressurized gas which is discharged through a conduit network (34, 36) for driving the safety restraint device. The system further includes a throttling valve assembly (32, 58) disposed between the fluid means and the safety restraint device (22, 24) for controllably varying the output of the fluid means. The throttling valve assembly is controlled by an electrical signal received from a crash management controller (38).

Description: VALVE CONTROLLED AUTOMOTIVE PYROTECHNIC SYSTEMS The present invention relates generally to an adaptive safety restraint system. In particular, the present invention is directed to a safety restraint system employing an electrically actuated throttling, or control valve, device for adaptively controlling the output of an inflator during airbag deployment. Safety restraint systems are used in motor vehicles for protecting the vehicle occupants during crashes. In addition to seat belts, many safety restraint systems include a driver-side airbag mounted in the steering wheel and a passenger-side airbag mounted in the instrument panel. Recently attention has been directed to incorporation of other restraint devices such as, for example, side airbags, seat belt pretensioners, and energy management retractors into the safety restraint system. Many of these restraint devices are activated by the vehicle's crash management system in response to detection of a vehicular crash exceeding a predetermined magnitude. Many airbag and safety restraint devices such as pretensioners (also called belt tighteners) are deployed in response to activation of an inflator or other pyrotechnic, gas generating device by the vehicle's crash management system. Typically, activation of the inflator (pyrotechnic device) generates a predetermined output, based on the magnitude of gas or propellant discharge, for deploying its associated airbag or safety restraint device. However, in order to optimize occupant protection during a crash, it is desirable to vary the deployment characteristics of the airbags and/or the operational characteristics of the other restraint devices based on various control parameters, such as the severity of the crash, seat belt usage, and the position, size and weight of the seat occupant. Thus, the vehicle's crash management system includes various sensors for detecting and/or measuring such control parameters and a controller for adaptively varying the inflator output in response to the sensor signals. One method for regulating the output of an inflator is through the use of an inflator having two or more separate stored energy devices, commonly referred to as a multi-level inflator. Accordingly, it is desirable to provide a lower cost system for controlling the mass flow and pressure of gas generated by the inflator. One such approach is to provide a single inflator having one or more control valve devices for selectively modulating the inflator output and adaptively controlling the deployment force provided to the safety restraint device. Accordingly, the present invention is directed to an adaptively controlled safety restraint system. BRIEF DESCRIPTION OF THE DRAWINGS The various advantages of the present invention will become apparent to one skilled in the art by reading the following specification and appended claims, and by referencing the following drawings in which: FIG. 1A is an environmental view of a vehicular seating unit showing the safety restraint system; FIG. IB is an environmental view of a vehicular instrument panel module showing a safety restraint system; FIG. 2 is a partial sectional view of a control valve module; FIGs. 3A-3C are partial sectional views of an airbag inflator having a throttling or control valve associated therewith for regulating the inflator output; FIG. 4 is a perspective view of a cylindrical airbag inflator having a valve for controlling the inflator; FIG. 5 is a partial sectional view of the airbag inflator and throttling device shown in FIG. 4; FIG. 6 is a perspective view of the throttling or control member; FIG. 7 is a side elevational view of the throttling or control member shown in FIG. 6; FIG. 8 is a perspective view of a toroidal-shaped airbag inflator having a valve for controlling the inflator output; FIG. 9 is a partial sectional view of the airbag inflator and throttling or control valve device shown in FIG. 8; FIG. 10 is a perspective view of the throttling or control; and, FIG. 11 shows a partial sectional view of an alternate valve. DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a low-cost airbag inflator employing an electrically actuated throttling valve for modulating the output of the airbag inflator and controlling the deployment force of the device or devices comprising the safety restraint system. With reference to FIG. 1A, an exemplary passenger compartment 16 includes a seat assembly 18 and a safety restraint system 20. In particular, safety restraint system 20 includes a side airbag 22 associated with the left side of seat assembly 18 and a seat belt pretensioner 24 for taking up slack in seat belt 26. A manifold assembly 28 houses a stored energy device 30 and can be located below a seat 18 or at another convenient location. A stored energy device 30, preferably a gas generator, such as any known pyrotechnic, hybrid, liquid or other known inflator which releases pressurized gas upon activation by the vehicle's crash management controller 38. However, one skilled in the art will readily appreciate that a variety of similar stored energy devices may be used at each seating position in accordance with the present invention. A plurality of throttling valve modules 32a, 32b, which may include pintle valves, spool valves (see FIG. 11) or other electrically control valves, are connected to manifold 28 and modulate and/or control the pressurized gas discharged from stored energy- device 30, through manifold 28 and into conduits 34, 36. Conduit 34 provides a side airbag 22 with pressurized gas and a conduit 36 provides a seat belt pretensioner 24 with pressurized gas. Other conduits may extend from a central source of inflation gas (the device 30) with additional valve modules to control the communication of inflation gases to a rear impact airbag 22a, located in the back of the seat to urge the upholstered seat against the back of the occupant to support the back of the occupant during a rear impact or crash, a knee or thigh airbag 22b located in the front top portion of the seat to raise the elevation of the front portion of the seat to limit the occupant's tendency to submarine during a frontal crash, and a center airbag 22c which is housed within the seat to prevent the occupant from moving toward the center of the vehicle during a side impact crash (or an oblique impact) . The added conduits and valves or valve modules may also be communicated to a seat belt retractor pretensioner which upon receipt of the inflation gas causes the spool of the retractor to reverse rotate thereby winding (retracting) the seat belt thereon to reduce slack about the occupant. The operation of valve modules 32a, 32b is controlled by the vehicle's crash management controller 38 which determines the position of the pintle member 78 (FIG. 2) for controlling the inflator gas pressure and mass flow delivered to each safety restraint device. The crash management controller 38 receives signals from various crash sensors 35 and occupant position sensors 37 located at various points in the vehicle to determine the type and severity of the crash. While only crash sensors 35 and occupant position sensors 37 are shown, it should be understood that many different types of sensors can provide signals to the crash management controller including, but not limited to, occupant weight and/or proximity sensors, child seat sensors, and temperature and other environmental condition sensors. As disclosed by the present invention, the operation of a side airbag 22 and pretensioner 24 may be independently controlled by crash management controller 38 in response to the information received from sensors 35, 37, and only requires the activation of a single stored energy device 30. For example, in a head-on crash, the crash management controller may determine that only pretensioning of a seat belt 26 is required. This is accomplished by opening pintle valve 32b for operating pretensioner 24, and closing pintle valve 32a for preventing deployment of side airbag 22. Alternatively, the crash management controller may open both pintle valves 32a, 32b for simultaneously operating both devices 22, 24. In addition, the amount, or degree, of opening of pintle valve 32a can be modulated for providing less inflator output to the airbag 22, thereby decreasing the deployment force of the airbag as it inflates, such as during a lower severity crash scenario. Moreover, the frequency at which throttling or control valves 32a, 32b are modulated can also be controlled by crash management controller 38. As will be appreciated, throttling valve modules provides considerable flexibility to the safety restraint system. Turning now to FIG. IB, an exemplary front instrument panel module 40 has a safety restraint system 42 installed therein. The safety restraint system includes a driver airbag 44 mounted within a steering wheel 46, a passenger airbag 48 mounted within a instrument panel module 40, and driver and passenger knee bolster airbags 50, 52 which are deployed from the lower portion of the instrument panel module. A manifold assembly 54 for housing a large stored energy- device 56 is secured behind or underneath instrument panel module 40. Preferably, stored energy device, or gas source 56, can be a pyrotechnic, hybrid, liquid or other known inflation device which releases pressurized gas into a manifold assembly 54 upon activation by the vehicle's crash management controller 38. As shown, four pintle valve modules 58a-58d are in fluid communication with the manifold assembly. Each device of the safety restraint system 42 is connected to its associated throttling valve module by a conduit 60a-60d. As shown, driver airbag 44 is connected to conduit 60a, driver knee bolster 50 is connected to conduit 60b, passenger knee bolster 52 is connected to conduit 60c, and passenger airbag 48 is connected to conduit 60d. Upon activation of stored energy device 56, pressurized gas is provided to pintle valve modules 58a-58d for controlled distribution to the individual safety restraint devices 44, 48, 50, 52 through conduits 60a-60d. As disclosed above, each device within the safety restraint system 42 can be independently operated, and the deployment force of each device controlled or modulated by valves 58a-58d and crash management controller 38. Accordingly, the crash management controller 38 may selectively operate the devices within safety restraint system depending on the type and severity of a given crash scenario in a similar manner as described above . Using one stored energy device 30, 56 has several advantages. Specifically, one squib may be used to activate, or inflate, four or more safety restraint devices. Further, only one stored energy device 30, 56 must be replaced after being discharged. These advantages represent a significant cost savings over prior art systems. Safety restraint systems 20, 42 also allow each device to be selectively disabled without removing its stored energy device 30, 56. FIG. 2 discloses the detailed components of valve modules 32, 58 that are substantially similar to each other, and will be described with reference only to pintle valve module 32. Preferably, pintle valve module 32 is contained within a housing 70 having an inlet 72 for connecting to the manifold 28, 54, and an outlet 74 for delivering pressurized gas to its associated conduit. The valve body 76 includes a pintle member 78 for engaging a valve seat 80 and controlling the flow of pressurized gas through a nozzle 82. As disclosed, pintle member 78 includes a rounded tip 84, which reduces the effects of turbulence within valve body 76. The opposite end of pintle member 78 is connected to an actuator 86 which controls the axial position of pintle member 78 within valve body 76 in response to an electrical control signal received from crash management controller 38. Preferably, actuator 86 is a stepper motor for controlling the axial movement of pintle member 78 within valve body 76. However, actuator 86 may also be a solenoid or electromagnet, connected directly to the pintle member 78 or an extending stem thereof, responsive to an electrical signal produced by crash management controller 38 for controlling the axial position of pintle member 78 relative to valve seat 80. In operation, actuator 86 maintains pintle member 78 in a retracted or open position when maximum flow of pressurized gas through nozzle 82 is required. However, the flow of pressurized gas is restricted or completely inhibited when actuator 86 places pintle member 78 in an extended or closed position for contacting valve seat 80. Moreover, actuator 86 is capable of maintaining pintle member 78 in any position within its operating range for controlling the flow of pressurized gas for any period of time. Accordingly, actuator 86 can modulate the position of pintle member 78 between its open and closed positions for adaptively changing the deployment force of its associated airbag or safety restraint device. Referring now to FIGs . 3A-3C, an alternate embodiment of the present invention is disclosed. More specifically, FIGs. 3A-3C show the pintle valve arrangement associated with an inflator assembly 90 which is generally defined by a manifold 92 for housing a stored energy device 94. Preferably, stored energy- device 94 is also a pyrotechnic inflator which releases a flow of pressurized gas upon activation. Manifold 92 includes a plurality of exhaust ports 96 which direct pressurized gas from stored energy device 94 into an airbag or conduit network (not shown) connected to manifold 92. As disclosed, manifold 92 includes four exhaust ports 96. However, one skilled in the art will appreciate that exhaust ports 96 can take on a variety of configurations dictated by the specific application for inflator assembly 90. The top of stored energy device 94 includes a plurality of apertures 98 for releasing pressurized gas into a valve chamber 100 which in turn controls the amount of gas directed into manifold 92 for inflating the associated airbag. More specifically, valve chamber 100 includes a discharge port 102 for directing gas into manifold 92, and a venting port 104 for directing gas away from inflator assembly 90 and the safety restraint system. A pintle valve member 106 is supported for axial movement within valve chamber 100 for adaptively changing the output characteristics of inflator 90. Pintle valve member 106 is generally defined by a lower pintle end 110 for engaging discharge port (valve seat) 102 and an upper pintle end 112 for engaging venting port (valve seat) 104. The axial position of pintle member 106 is controlled by an actuator 108 in response to an electrical control signal sent to actuator 108 from the vehicle's crash management controller (CMC) 38. Preferably, actuator 108 is a solenoid or stepper motor for controlling the axial movement of pintle valve member 106 within valve body 100. In operation, pintle valve member 106 can be moved between an upper position (FIG. 3A) for directing the maximum amount of pressurized gas into manifold 92 through discharge port 102 and a lower position (FIG. 3B) for venting the pressurized gas away from manifold 92 through venting port 104. Pintle valve member 106 can also be located into any position within its range of motion for generating a range of output force to an attached safety restraint device (not shown) through manifold 92. This intermediate position (FIG. 3C) for pintle member 106 allows pressurized gas to flow simultaneously through primary port 102 and venting port 104 for deploying the attached safety restraint device with reduced force. The position of pintle member 106 is also determined by CMC 38 in response to various sensors which determine the severity of impact, such as crash sensors 35 and occupant position sensors 37 as discussed above. With reference now to FIGs. 4 through 7, another preferred embodiment of the present invention is shown. FIG. 4 discloses a cylindrical inflator 120 as including a stored energy chamber 122 for releasing pressurized gas upon activation by crash management controller 38. The flow of pressurized gas is controlled by a pintle valve assembly 124 which is securely positioned for fluid communication with a plurality of exhaust ports 126 formed about the neck of stored energy chamber 122. FIG. 5 shows pintle valve assembly 120 with a cylindrical airbag inflator 122 and a manifold 128 having a plurality of apertures 130 formed therein. Airbag pintle valve assembly 124 is generally defined by a valve body 132 that provides the primary structure to pintle valve assembly 124. The inboard end of valve body 132 is inwardly tapered to define an annular valve seat 134. The outboard end of valve body 132 is securely attached to actuator 136, which is in turn secured to a threaded shaft 138 of the inflator 122 with a nut 140. Pintle member 142, preferably metal, is axially supported by stored energy device 122, and also supported within valve body 132. A plurality of flow orifices 144 are formed around a neck portion 146 of pintle member 142 which communicate with exhaust ports 126 for allowing pressurized gas to flow therethrough during deployment of the inflator 122. Actuator 136 is preferably a solenoid for controlling the axial position of pintle member 142 with respect to valve seat 134. When pintle member 142 is moved away from actuator 136, pintle end 148 engages valve seat 134 for restricting or blocking the flow of pressurized gas from pintle valve assembly 124. When actuator 136 retracts pintle member 142 such that pintle end 148 is displaced from valve seat 134, pressurized gas flows through orifices 144 and out pintle valve assembly 124 into manifold 128 which directs the pressurized gas into the associated safety restraint device via apertures 130. A gasket or seal 149 may optionally be provided between stored energy device 122 and pintle member 142. FIGS. 6 and 7 further disclose the various features of pintle member 142. More specifically, the axial body 150 sits within a recess 154 of actuator 136. This feature facilitates the interaction between pintle member 142 and actuator 136 for controlling the extended or retracted position of pintle member 142. The annular collar 152 further assists in supporting pintle member 142 within valve body 132. Pintle end 148 is also shown to include a large surface area for engaging valve seat 134 and creating a tight seal when pintle member 142 is fully extended by actuator 136. Turning now to FIGS. 8 through 10, an alternate construction of the pintle valve controlled inflator is shown in accordance with the preferred embodiment of the present invention. FIG. 8 discloses a toroidal inflator 160 that is generally defined by a tapered valve body 162 and a cover plate 164 which when assembled forms a two-piece enclosure. A stored energy device 166, such as a pyrotechnic inflator, is secured within toroidal inflator 160 and discharges pressurized gas upon activation by crash management controller 38. Inflator 160 is typically included as the inflator component of an airbag module integrated into the central portion of a vehicular steering wheel, such as steering wheel 46 shown in FIG. IB. FIG. 9 shows details associated with the components of toroidal inflator 160. More specifically, the tapered end of valve body 162 defines an annular valve seat 165. The stored energy device 166 contained within inflator 160 includes a plurality of exhaust ports 168 around the outer circumference thereof. The stored energy device 166 also includes a threaded shaft 172 that allows for securing the actuator 170 with a nut 174. Pintle member 142', also preferably metal, is axially supported by actuator 170 and stored energy- device 166, and also supported within valve body 162. A gasket or seal 167 may optionally be provided between stored energy device 166 and pintle member 142 ' . A plurality of flow orifices 144 ' are formed around the neck portion 146' of pintle member 142' which communicate with exhaust ports 168 for allowing pressurized gas to flow therethrough during activation of the stored energy device 166 within toroidal inflator 160. Actuator 170 is also preferably a solenoid for controlling the axial position of pintle member 142 ' with respect to valve seat 165 in response to an electrical control signal from crash management controller 38. It should be understood that pintle member 142 ' and its associated features are substantially similar to pintle member 142, the primary difference being that pintle member 142 ' is designed to operate within and to the specifications of toroidal inflator 160. When pintle member 142' is moved away from actuator 170, pintle end 148' engages valve seat 165 for blocking the flow of pressurized gas from toroidal inflator 160. When actuator 170 retracts pintle member 142' away from valve seat 165, pressurized gas flows through orifices 144' and out toroidal inflator 160 for directing the pressurized gas into the associated airbag or safety restraint device. Additionally, actuator 170 may control the operation of toroidal inflator 160 by modulating the position of pintle member 142 ' within valve body 162 for correspondingly modulating the flow of pressurized gas therefrom. FIG. 10 further discloses the features and overall shape of pintle member 142'. The axial body 150' interacts with actuator 170 for controlling the extended or retracted position of pintle member 142 ' . The annular collar 152 ' further assists in supporting pintle member 142' within valve body 162. Pintle end 148 ' is shown to include a large surface area for engaging valve seat 164 and creating a tight seal for restricting the flow of pressurized gas when pintle member 142' is fully extended. FIG. 11 illustrates an alternate embodiment of the present invention. More specifically, a plurality of spool valves 200a, b, c are used to control fluid communication with corresponding safety restraint devices, for example devices 22, 22a and 22c. Each of the valves 200a, b and 200c are of identical construction and consequently only valve 200a will be described in detail. A central energy source such as a single inflator 28 is communicated via a plurality of conduits 34, 34a and 36 to each safety restraint device through an associated valve 200a, b, c. The valve 200a includes a valve body 202 in fluid communication with its associated conduit such as 34a and to a device such as 22c. The body includes a plurality of input ports such as 204a-c and a plurality of output ports such as 206a-c. A spool 210 is situated within a bore 208 of the body 202. The spool 210 is of a magnetic material such as steel, having a like plurality of grooves 212. Situated within the body 202 are two opposingly located electromagnets 214a, b. As each electromagnet is activated, the spool 210 is shuttled up and down selectively opening and closing ports 204a-c and 206a-c to control the amount of fluid (inflation gas) communicated to the safety restraint device dependent upon the duty cycle of a control signal (s) controlling the electromagnets 214a and 214b. Reference is briefly made to Table 1 which illustrates the operational inflation strategy to be used when activating one or more safety restraint devices during a selected type of accident such as a frontal impact, a side impact, a rear impact and a rollover crash. For example if the various crash sensors within and about the vehicle identify the crash event as a frontal impact (frontal crash) then the various valve modules connected to the designated restraint device, identified below, would be activated to protect the occupant in the selected type of crash event . In the case of a frontal impact the activation of the valve controlling the inflation of the rear impact bag 22a would be delayed a predetermined amount of time relative to the activation of the frontal airbag to prevent the occupant from rebounding. Similarly, in a rear impact the activation of the frontal airbag would be delayed.

Claims: CLAIMS 1. An adaptively controlled safety restraint system (20) comprising: at least one safety restraint device (22, 24) operative in response to a flow of pressurized gas; fluid means (28) in fluid communication with the safety restraint device for providing energy to drive the safety restraint device to an activated state of operation; and a valve means (32, 58) disposed between the fluid means and the safety restraint device for controllably varying the energy output of the fluid means communicated to the safety restraint device, the valve means being controlled by an actuator (86) in response to an electrical signal received from a crash management controller (38) . 2. The safety restraint system of Claim 1 including a conduit (34, 60) for directing the pressurized gas from the fluid means (28) to the safety restraint device (22, 24). 3. The safety restraint system of Claim 2 wherein the valve means (32, 58) is disposed along the conduit (34, 60) . 4. The safety restraint system of Claim 1 wherein the valve means (32, 58) includes a valve member (78) operably associated with the actuator (86) , and a valve body (76) for supporting the valve member, the valve body including a valve seat (80) for engaging the valve member . 5. The safety restraint system of Claim 4 wherein the valve member (78) is positionable by the actuator (86) between a first position for allowing the flow of pressurized gas to pass therethrough, and a second position for blocking the flow of pressurized gas. 6. The safety restraint system of Claim 1 wherein the valve means (32, 58) includes a valve member (106) operably associated with the actuator (108) , and a valve body (100) for supporting the valve member, the valve body including a discharge port (102) for directing the flow of pressurized gas into the safety restraint device (22, 24) and a venting port (104) for directing the flow of pressurized gas away from the safety restraint device (22, 24). 7. The safety restraint system of Claim 6 wherein the valve member (106) is positionable by the actuator (108) between a first position for allowing pressurized gas to flow through the discharge port (102), and a second position for allowing pressurized gas to flow through the venting port (104) . 8. The safety restraint system of Claim 7 wherein the valve member (106) is positionable by the actuator (108) into a position intermediate the first position and the second position for allowing pressurized gas to flow simultaneously through the discharge port (102) and the venting port (104) . 9. The safety restraint system of Claim 4 wherein the actuator (86) is a stepper motor (36) operably coupled to the valve member (78) for controlling the position of the valve member (78) with respect to the valve seat (80) . 10. The safety restraint system of Claim 4 wherein the actuator (86) is a solenoid (136) operably associated with the valve member (142) for controlling the position of the valve member (142) with respect to the valve seat (134) .

Inventors: DYBRO NIELS, KELLER GERALD, RAINES JASON, SIKORSKI JEFFREY, DYBRO, NIELS, KELLER, GERALD, RAINES, JASON, SIKORSKI, JEFFREY
Applicants: BREED AUTOMOTIVE TECH, BREED AUTOMOTIVE TECHNOLOGY, INC.
Application year: 1999
Main classification: B60R21
IPC codes: B60R21, B60R22