MXPA01007320A - Igniter - Google Patents

Abstract

An igniter (10) for igniting a reactive material has a conductor (13, 14) for conducting power and communication signals to and from the igniter. A controller (59) is located within the igniter. The controller is preferably an application specific integrated circuit. The controller has communication means for communicating with a master controller located remote from the igniter. The controller also has diagnostics means for comparing established parameters for components of the igniter to predetermined limits and sending fault warning messages and integrity status messages to the master control unit. The controller also further has means for receiving a unique igniter activation command from the master control unit and sending an activation signal to an igniter activation means that couples the energy stored in an energy storage capacitor (62) to a heating member (55) that ignites a reactive material (49).

Description

LIGHTER The present invention relates, generally, to ignition devices for reactive materials and, more specifically, to igniters that have the ability to interpret control signals, to determine when this igniter should ignite a reactive material, for example a reactive material in a gas generator, associated with a device to protect the occupant of a vehicle in the event of a collision. There are several scenarios in which it is convenient to selectively turn on separate units of reactive materials, or simultaneously or in sequence, depending on the selected variables. For example, in the case of a collision of a vehicle, it would be advantageous if the gas generators used in the activation of various vehicle occupant protection devices, such as air bags and pre-tensioning mechanisms of the seat belt, are actuated. by a master control unit, which communicates with the remote control units of the device, located in the gas generators, to selectively activate the gas generators depending on the various parameters. It would also be advantageous to have similar capabilities to selectively ignite several units of reactive materials, such as explosives, in mining or demolition operations.

A conventional type of system to control the start of the gas generators used in the activation of the vehicle occupant protection devices, uses a central electronic control unit, with a microprocessor. These systems usually have limited means of detecting component failures. Another problem with activation of the occupant protection devices of a vehicle, from a central electronic control unit, is that the activation signals are transmitted by wiring, directly to the vehicle occupant protection device. The short circuits of cables of the signal of activation to the voltage of the battery or to earth, can accidentally activate a device of protection of the occupant of the vehicle. Induced transient interference and other electromagnetic interference may also have detrimental effects on the operation of the safety device in such a system. Still another disadvantage of such a system is that additional components must be added to the central electronic control unit as additional security devices are added to a system. This adds to the space required to accommodate the central electronic control unit in the vehicle. U.S. Patent Nos. 5,825,098 and 5,835,873 address problems left unresolved by the conventional types of vehicle occupant protection control systems discussed above. U.S. Patent No. 5,825,098 teaches a driver of the occupant safety device of a vehicle, which is capable of activating various safety devices to protect the occupants of a vehicle in the event of a collision. This safety device controller is capable of performing self-tests and sending the results of these tests to an electronic master control unit on a communications manifold. Upon receipt of a coded command from the electronic control master unit, the safety device controller activates a safety device by discharging the energy stored in a detonator or electromechanical device to activate the safety device. U.S. Patent No. 5,835,873 teaches a vehicle occupant protection system, having a master controller and a plurality of safety device controllers, remotely located. The master controller receives the input signals with respect to the selected variables, such as the location of the seat, severity of the collision, size of the occupant of the seat, etc. The system provides fault detection and notifies the vehicle operator, as well as the immunity of electromagnetic interference through the use of remotely located safety device controllers that communicate with the master electronic controller over a digital communications collector, which uses commands and encoded data. Each of the security device controllers, remotely located, has the ability to perform self-tests and communicate with the master electronic control unit. Lighters of reactive materials are provided in accordance with the present invention, in which these lighters have the ability to interpret the control signals to determine if this lighter should ignite the reactive material, for example in a gas generator. Such a lighter can be used as a component of the occupant safety systems of the vehicle of the types described in US 5,825,098 and US 5,835,873. Patent GB 2 123 122 teaches a lighter having a microelectronic circuit, but does not teach or suggest that the microelectronic circuit has the ability to perform self-tests and send the results of these tests to a central electronic control unit, on a manifold of communications, such as the lighter of the present invention. A lighter having a controller of the device integral with it is provided, according to the present invention, as set forth in appended claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS The construction and method of operation of the invention, together with its objects and advantages, will be better understood from the following description of the specific embodiments, when read in conjunction with the accompanying drawings. Figure 1 is a perspective view of a lighter, according to the invention. Figure 2 is a perspective view, with separate pieces, of the lighter of Figure 1. Figure 3 is another perspective view, with separate pieces, of the lighter of Figure 1, looking in the opposite direction from the point of view. FIG. 4 is an end view of the lighter of FIG. 1. FIG. 5 is a longitudinal cross-sectional view of the lighter of FIG. 1, taken along line 5-5 of FIG. Figure 4. Figure 6 is a plan view of the first side of a circuit board, which is a component of the lighter of Figure 1.

Figure 7 is a plan view of a second side of a circuit board, which is a component of the lighter of Figure 1. Figure 8 is a cross-sectional view of an assembly of the lighter of Figure 1, with a gas generator. Figure 9 is an enlarged fragmentary view of a portion of the assembly shown in Figure 8. Figure 10 is a schematic representation of the electrical circuit in the circuit board shown in Figures 6 and 7.

Detailed Description of the Invention Referring first to Figure 1, a perspective view of a lighter 10 is shown, according to the invention. The structure and function of the lighter can best be described by referring simultaneously to Figure 2, which is a perspective view, with separate pieces, of the lighter, and Figure 3, which is another perspective view, with separate parts, of the lighter, which looks from the opposite direction from the point of view of Figure 2. A plastic end cap 11 is provided at one end of the lighter 10. Two metal pins, 13, 14 extend through the end cap of plastic, by means of passages 17, 18 in this plastic end cap. One of the pins is a power supply pin and the other is a return pin. Thus, in this exemplary embodiment, there is an interface of two pins that are of different polarity. The pins perform the functions of driving power to the lighter and driving the digital communication signals to and from the cigarette lighter. Of course, if desired, a configuration of three pins, with two pins for the power supply and a third pin for driving the digital driving signals, can be employed, without departing from the scope of the present invention. A metal disc 26, sometimes referred to as a manifold, is disposed adjacent the plastic end cap 11 and has passages 27, 28 therethrough, which accommodate the passage of the electrically conductive pins through the disc. metal. A projection 29 extends from one side of the metal disc and has an enlarged head 30, which facilitates the molding of the plastic end cap with the metal disc in this exemplary embodiment. It will be understood that alternatively the plastic end cap can be attached to the metal disc by any suitable element for joining, such as by adhesives, rivets, threaded fasteners, heating the metal disc and pressing it into the plastic end cap, etc. Seals are formed between the electrically conductive pins, 13, 14, and the metal disc, by any suitable means, such as by placing glass tubes, 33, 34 around the electrically conductive pins, so that these glass tubes are placed. in the regions of the passages 27, 28 through the metal disc and when the glass tubes are heated, to form glass to metal seals between the glass and the electrically conductive pins and the glass and the metal disc. Glass not only acts as a seal but also as an electrical insulator between the electrically conductive pins and the metal disc. It will be understood that any other suitable means for forming a seal between the electrically conductive pins and the metal disc and electrically insulating these electrically conductive pins and the metal disc, such as an epoxy resin or plastic, can be employed in the practice of the present invention. The metal disc 26 is provided with a circumferentially extending flange 35 which is placed on the side of the metal disc and which will face the circuit board when the lighter is assembled. A metal ring 36 is provided with a flange 36, which extends circumferentially at its end, which is complementary to the flange 35 of the metal disc and the two flanges are retained in physical engagement with each other. A second end 40 of the metal ring abuts the circuit board 25. This metal disk 26, metal ring 36 and circuit board 25, cooperate to define a chamber 43, which is best shown in Figure 5, which is a longitudinal cross-sectional view of the lighter of Figure 1, taken along line 5-5 of Figure 4. Each of the pins 13, 14 is in electrically conductive contact with the circuit board 25 in the region of a second end 21, 22 of the pin. In this exemplary embodiment, the electrically conductive pins extend through passages 23, 24 within the circuit board, and are secured to the circuit board using an electrically conductive epoxy resin. In this exemplary embodiment, pins 1 | 3, 14 carry an operating current of about 1 milliampere and are made of a nickel / iron alloy. Preferably, each pin is plated with gold, along a portion of its length, starting at the first end 19, 20, to provide a high integrity, conductive friction contact with a wired harness connector that is identified by the reference character 110 in Figure 9. The circuit board 25 may comprise any suitable material, such as a plastic or ceramic material. In this exemplary embodiment, the circuit board is an aluminum oxide ceramic member, which has several circuit components attached, which are better understood with reference to Figures 6, 7 and 10. Figure 6 is a plan view schematic of the side of the circuit board, which faces away from the chamber 43. Figure 10 is a schematic representation of the electronic circuitry of the exemplary lighter and the components associated with this circuit board. In Figure 10, the components of the electronic circuit system are identified by the same reference characters as in Figures 6 and 7. Several channels 51 extend through the circuit board in the usual manner, to facilitate electrical circuits, which extend between the opposite sides of the circuit board. Several test blocks 53 are printed on the circuit board in the usual way, to facilitate quality control tests of the electronic parts.

Two printed resistors 63, 64 supply the resistance of the regulator and suppress electromagnetic interference ("EMI"). In this exemplary embodiment, the resistivity of the printed resistors 53, 54 is around 110 ohms. Another resistor 60 establishes a diagnostic current for a controller 59, which is located on the opposite side of the circuit board. In this exemplary embodiment, the resistivity of this resistor is around 75K ohms with a variation of 1%.

Referring now to Figure 6, which is a schematic plan view of the side of the circuit board facing the chamber 43, and Figure 10 which is a schematic representation of the electronic circuitry of the exemplary lighter and the associated components , with this side of the circuit board that can be described. A heating member 55 is located on the side of the circuit board, which faces away from the chamber 43. The gas generation reaction in most gas generators starts with a heating member, which is a wire of bridge. A material of the bridge wire is selected from metals alloys, with high melting temperature, which are resistant to corrosion, firm enough to withstand the loading pressures of the reactive material and which can be welded to the electrical connectors. An electric current passes through the wire bridge and generates heat, which ignites the reactive material. Alternatively, a thin conductive film, electronically deposited, can be used as a heating member. However, it is preferred that the heating member of a lighter, according to the present invention, may be a semiconductor bridge. Examples of semiconductor bridges are described in US Patents 4,708,060; US 4,085,146 / US 4,976,200; US 5,179,248 and US 5,309,841, which teach semiconductor bridges that can be used in the practice of the present invention. A semiconductor bridge comprises a non-metallic substrate, which carries a semiconductor layer, preferably comprising a silicon with impurities. A pair of electrically conductive zones, made, for example, of aluminum or tungsten, are deposited in the semiconductor layer, so that a gap separates the zones. A reactive material makes contact with the hollow zones and bridges. When electricity of sufficient voltage and current is applied, through the gap, by means of the zones, a plasma is established in this gap. The plasma initiates the reactive material, which, in turn, initiates the intensifier, which, in turn, initiates the compound that generates gas in the gas generator. Varistors 57, 58 provide protection against electrostatic discharge ("ESD"). A decoupling capacitor 52 decouples the transient changes from the controller 59. In the exemplary embodiment, this decoupling capacitor has a capacitance of about 0.1 microfarad. A controller 56 stores energy, which will be discharged to a heating member 55, when the lighter is activated. In exemplary mode, this device that stores energy has a capacitance of about 2.2 microfarads.

In the preferred embodiment, the controller 59 is an application-specific integrated circuit (ASIC) that provides the control and diagnostic functions for the lighter. This controller includes communication means to receive activation of the lighter and the integrity data commands from the electronic control unit (ECU) master by high-speed via, bi-directional serial communication collector, digital electronic, and to send integrity data and fault warning messages in the bi-directional, electronic, digital, high-speed serial communication manifold. Alternative modes to this bi-directional, electronic, digital, high-speed serial communication collector include: a bi-directional, electronic, digital, high-speed parallel communication collector; a high-speed, digital electronic serial communications collector comprised of two electrical conductor cables; and a bi-directional, high-speed digital fiber optic serial communication collector. The ECU (not shown) communicates with at least one lighter, but, advantageously, this ECU communicates with a plurality of lighters. The ECU also communicates with sensors, such as, but not limited to, collision sensors, sensors of the size and position of the vehicle occupant, bearing sensors, seat position sensors and sensors of the seat belt use. A vehicle occupant sy device control system of this type is taught in US 5 825 098 and US 5 835 873, which teach a vehicle occupant sy device control system, which advantageously employs the lighter of the invention. The controller has diagnostic elements for comparing the integrity data of the igniter controller, energy storage capacity data, and ignition cycle integrity data (heating element activation circuitry) to predetermined limits and generate messages of Failure warning and integrity status messages to the ECU. The diagnostic element comprises, for example, a multichannel and an analog to digital converter, for reading the integrity data of the security device and for sending this integrity data from the controller to the ECU. The controller has means for receiving a unique activation command of the digital lighter from the CU and for sending the activation signal to an igniter activation element. This igniter activation element comprises one or more switches for coupling the energy stored in a power storage capacitor to the heater 55 to ignite the reactive material upon receiving the activation signal from the controller.

In a further embodiment of the invention, the device activation command and the integrity data command are comprised of a binary coded address part and a binary coded command part. The controller further comprises a charge pump, which is an energy conversion element, which comprises a direct current to direct current converter for driving the power provided by the serial, bi-directional, electronic, digital, communication communications collector. high speed, to supply the driven power to an energy storage capacitor 56 and, if desired, to supply voltages of the power supply to selected electronic circuits of the lighter. In the exemplary embodiment described herein, the communication element, diagnostic element, element for receiving a unique digital signal from the lighter and an element for sending an activation signal to an igniter activation element, and the charging pump, are contained in the electronic circuit system of the ASIC. In summary, the control activation of a lighter, according to the invention, includes the activities of: storing energy in an energy storage capacitor from an energy supply, charging the energy storage capacitor comparing the integrity data from the igniter controller, the energy storage capacity data and the ignition cycle integrity data to predetermined limits and generating fault warning messages and integrity messages to the ECU; which receives a unique activation command of the lighter from an ECU on a communications collector; sending an activation signal of the device to a lighter activation element; and coupling the energy stored on the energy storage capacitor to the device of the heating member, causing the energy storage capacitor to discharge through a heating member, causing a chemical reaction to begin. In the case of a vehicle occupant protection device, the chemical reaction generates a gas that is used to inflate an airbag, drive a piston in a pre-tension device, cause a reel to rotate in a tension device previous or any other desired use. The ceramic circuit board, used in this exemplary embodiment, may not possess the level of resistance that is required of this component in the structure of the lighter. It is recommended to fill the chamber 43 with epoxy material, such as the HYSOL-FD4450 HF from Dexter, to supply the support for the ceramic circuit board. The injection of the epoxy material into the chamber is facilitated by two holes, 38, 39, through the metal ring 36. One of the holes 38 is larger than the other 39. The epoxy material is injected into the chamber through the larger orifice and the smaller orifice allows air to be forced from the chamber, as the epoxy material displaces the air. After the chamber 43 has been filled with the epoxy material, an elastomer washer 44 is placed against the side of the circuit board, which faces away from the chamber 43. A tubular metal member 45, having a collar 46 at one end , it is placed around other components with the collar 46 extending around the metal disk 26. The collar of the tubular metal member is then fixed to the metal disk 46, by any suitable means. In the exemplary embodiment, the collar of the tubular metal member is fixed to the metal disk 26 by laser welding. A reactive material 49 is placed in a chamber 46, defined by the tubular metal member 45 and the side of the circuit board 25 that faces away from the chamber 43. In the exemplary embodiment, the reactive material is in powder or granular form. and is tamped into chamber 46 using a force of about 680 atmospheres. The epoxy material in chamber 43 on the opposite side of the circuit board, supports this circuit board and prevents the circuit board from being damaged during the tamping procedure. The open end 47 is then sealed. In the exemplary embodiment, this seal is made by inserting a metal disc 48 at a short distance into the tubular metal member 45. The metal disc 48 has a diameter only slightly smaller than the internal diameter of the tubular metal member 45. The end 47 The metal tubular member is then bent radially inside, APRA ensuring the metal disc in place against the reactive material. A coating 50 of a forming material is placed on the metal disc and the end 47 of the tubular metal member, to create a seal to the environment. In the exemplary embodiment, the shaping material is cured with ultraviolet light. The assembly of a lighter of the present invention with a gas generator is better understood with reference to Figures 8 and 9. Figure 8 is a cross-sectional view of an assembly of the lighter 10 with a gas generator 100. Figure 9 is an enlarged fragmentary view of a portion of the assembly shown in Figure 8. This exemplary gas generator has a housing, which defines a first chamber 105, which contains a reactive material, which is a material that intensifies ignition , or sizing, and a second chamber 109, which contains a reactive material that generates gas when ignited. The lighter 10 ignites the reactive material in the first chamber 105, which passes through the openings 107, to ignite the reactive material in the second chamber 109. The gas generated by the reactive material in the second chamber, typically passes through of the filter 111 and exits the gas generator through the openings 113 to inflate an air bag, or to operate a pre-tension device or other gas operated device. A member 103 receiving the lighter secures this lighter to the gas generator. It will be understood that the gas generator, shown in Figures 8 and 9, is merely exemplary and that the lighter of the present invention can be used with any design of the gas generator, and that the simple device of the gas generator can be assembled with more than one lighter of the present invention. It will be understood that the lighters of the present invention can be used with hybrid inflation devices of the air bag.

Claims (10)

1. CLAIMS 1. A lighter, comprising in a simple unit: (a) a housing; (b) a driver to conduct the energy and communication signals to and from this lighter; (c) a heating member, for igniting a reactive material (d) a controller, located inside the housing, this controller has: i) communication elements for the activation commands of the lighter, from a master control unit and to send integrity data and fault warning messages to the master control unit, ii) diagnostic elements, to compare the integrity data of the igniter controller, the energy storage capacity data and the cycle integrity data ignition, to predetermined limits and generate warning messages of failures and messages of the integrity status to the master control unit, iii) elements to receive a unique activation command of the igniter, from the master control unit and send an activation signal to an activation element of the lighter, which couples the energy stored in an energy storage capacitor to the heating member to
2. 2. The lighter of claim 1, wherein the controller, positioned within the housing of the lighter, further comprises a charge pump, which supplies driven energy to the energy storage capacitor.
3. 3. The lighter of claim 1 or 2, wherein the controller, placed within the housing of the lighter, is an application-specific integrated circuit.
4. 4. The lighter of any of claims 1 to 3, wherein the heating member is a bridge wire.
5. 5. The lighter of any of claims 1 to 3, wherein the heating member is a thin conductive film.
6. 6. The lighter of any of claims 1 to 3, wherein the heating member is a semiconductor bridge.
7. 7. The lighter of any of claims 1 to 6, further comprising a circuit board to which the heating member, the controller and the energy storage capacitor are attached.
8. 8. The lighter of any of claims 1 to 6, further comprising a circuit board, to which the heating member, the controller and the energy storage capacitor are attached, this controller and the heating member are placed on the sides opposite of the circuit board.
9. 9. The set of a gas generator and a lighter, in which this lighter comprises: (a) a housing; (b) a driver to conduct the energy and communication signals to and from this lighter; (c) a heating member, for igniting a reactive material (d) a controller, located inside the housing, this controller has: i) communication elements for the activation commands of the lighter, from a master control unit and to send integrity data and fault warning messages to the master control unit, ii) diagnostic elements, to compare the integrity data of the igniter controller, the energy storage capacity data and the cycle integrity data ignition, to predetermined limits and generate warning messages of failures and messages of the integrity status to the master control unit, iii) elements to receive a unique activation command of the igniter, from the master control unit and send an activation signal to an igniter activation element, which couples the energy stored in an energy storage capacitor to the heating member or
10. 10. The whole hybrid gas generator and a lighter, in which this lighter comprises: (a) a housing; (b) a driver to conduct the energy and communication signals to and from this lighter; (c) a heating member, to light a reactive material (d) a controller, located inside the housing, this controller has: i) communication elements for the lighter activation commands, from a master control unit and to send integrity data and warning messages of faults to the master control unit, ii) diagnostic elements, to compare the integrity data of the igniter controller, the data of the energy storage capacity and the data of the 10 ignition cycle integrity, to predetermined limits and generate fault warning messages and integrity status messages to the master control unit, iii) elements to receive an activation command 15 of the igniter, from the master control unit and send an activation signal to an igniter activation element, which couples the energy stored in an energy storage capacitor to the ignition member. 20 heating.