Gas generator

Abstract

The invention relates to a gas generator (10) having a tubular housing (12) filled with a compressed gas (28) and a fuel vessel (30) filled with gas-generating propellant grains (36), wherein the fuel vessel (30) has a circumferential wall (32) which runs around in a circumferentially closed manner and has a plurality of through-flow openings (50). An interior space (34) of the fuel vessel (30) and at least one free space (56) formed radially between the circumferential wall (32) and an inner side (54) of the housing (12) are permanently connected in terms of flow via the circumferential wall (32) in the non-activated and in the activated state of the gas generator (10). The fuel vessel (30) has, at an igniter-side axial end (38), a gas inflow opening (40) through which a shock wave (21) enters the fuel vessel (30) when the gas generator (10) is activated, wherein the at least one free space (56) forms a shock wave channel, which is permanently open towards the diffuser-side end (22) of the housing (12), for the shock wave (21) passing through the circumferential wall (32).

Description

[0001] ZF Airbag Germany GmbH

[0002] Wernher-von-Braun-Str. 1

[0003] 84544 Aschau am Inn / Germany

[0004] Gas generator

[0005] The invention relates to a gas generator with a tubular housing filled with a pressurized gas and a fuel container filled with gas-generating fuel bodies, which is arranged inside the housing.

[0006] These hybrid gas generators are used, for example, to fill a gas bag in a vehicle, which serves to protect vehicle occupants. There is an increasing demand for gas generators with the smallest possible outer diameter. However, with a decreasing outer diameter, it becomes increasingly difficult to evenly distribute the propellant tablets, as the chambers designated for this purpose naturally become narrower.

[0007] The object of the invention is to create a gas generator that allows for easy filling even with a small housing diameter and provides uniform gas development when activated.

[0008] This problem is solved by a gas generator with a tubular housing filled with a pressurized gas. The generator has an igniter, housed in an igniter cap, at an axial end on the igniter side, and a diffuser with at least one gas outlet opening at the opposite end on the diffuser side. The gas generator comprises a fuel reservoir filled with gas-generating propellant particles, which is arranged inside the housing. The fuel reservoir has a circumferentially closed wall with a plurality of flow openings. An interior space of the fuel reservoir and at least one free space formed radially between the circumferential wall and an inner surface of the housing are in constant flow communication via the circumferential wall, both in the deactivated and activated states of the gas generator.The fuel container has a gas inlet opening at an igniter-side axial end, through which a shock wave enters the fuel container when the gas generator is activated, the at least one free space forming a shock wave channel permanently open towards the diffuser-side end of the housing for the shock wave that passes through the circumferential wall.

[0009] The shock wave can thus enter the fuel tank in a straight line. It then spreads radially or obliquely outwards into the cavity(ies). Within each cavity, the shock wave travels unimpeded along the axial direction of the housing to the end of the fuel tank and then continues axially undisturbed within the housing. The cavity(ies) therefore act as a kind of bypass for the shock wave, allowing it to largely circumvent the fuel tank. In this way, the shock wave is only minimally weakened and delayed.

[0010] The part of the shock wave that propagates axially through the fuel container ensures, for example, a uniform mixing of the gases produced by the burning fuel bodies and thus supports a uniform combustion of the fuel bodies.

[0011] Generally, there is no obstruction to the shock wave in the respective free space, in particular no propellant bodies or components protruding from the propellant container, so that the shock wave can propagate unhindered in the axial direction through the free space and from there into the rest of the housing's interior. Normally, the respective free space is open at the end of the propellant container furthest from the igniter and transitions directly into the rest of the housing's interior.

[0012] The fuel reservoir can be positioned radially in the center of the housing. This allows, firstly, the fuel reservoir to be designed with a geometry that makes it easy to fill with propellant particles, even with smaller diameters. Secondly, the fuel reservoir can be easily positioned in the axial extension of the igniter.

[0013] Another advantage is that the free space(s) at least partially separate the fuel elements radially from the housing wall. This results, for example, in better cooling of the incoming pressurized gas during filling, thus reducing the thermal stress on the fuel elements. The free space(s) therefore allow for shorter filling times, as the compressed gas, heated during filling, remains in contact with the housing wall as it flows through the free space and is thereby cooled. Furthermore, during a bonfire test, for example, heat transfer to the fuel elements is less direct.

[0014] Since only the fuel tank needs to be inserted into the housing, only a small number of components are required, which simplifies manufacturing and saves costs.

[0015] As is known with such hybrid gas generators, the housing forms a pressurized gas container. The pressurized gas can, for example, be contained within the housing at a pressure greater than 550 bar at room temperature.

[0016] The gas permeability of the fuel tank's circumferential wall can be easily adjusted by the number, size, and arrangement of the flow openings. For example, there can be many small openings, from 50 to 500 or more, where the openings are smaller than the fuel particles contained within the tank. In one design, the flow openings are evenly distributed across the entire circumferential wall. An uneven distribution is also possible, and the flow openings can have different sizes and / or shapes. Generally, the flow openings should be arranged so that the shock wave can pass radially outward into the free space(s) through the circumferential wall with minimal resistance and flow losses. The flow openings also reduce the weight of the fuel tank.

[0017] The outer wall can be made, for example, from perforated sheet metal, expanded metal, or a suitable composite material. The fuel tank can be manufactured cost-effectively from any of these materials in a wide variety of geometries.

[0018] For example, a first rupture membrane is located on the igniter cap. This membrane bursts when the igniter is activated, generating the shock wave. The first rupture membrane lies axially between the igniter and the propellant reservoir and is instantly destroyed by the activation of the igniter. Once the shock wave has passed through the housing, it typically encounters a second rupture membrane at the diffuser-side axial end of the housing and opens it. The gas formed by the pressurized gas and the burning propellant particles can then escape through a diffuser at the diffuser-side end of the gas generator. Before the gas generator is activated, the housing is sealed pressure-tight against the pressurized gas contained within by the two rupture membranes.

[0019] In one possible variant, the free space widens towards the diffuser-side end, for example along the radial direction and / or the circumferential direction, so that the flow resistance for the shock wave in the axial direction is reduced.

[0020] The fuel reservoir can be inserted into the housing in such a way that its gas inlet opening axially overlaps the igniter cap, enabling a particularly compact design. The igniter cap, similar to that of conventional gas generators, is a pot-shaped, one-piece, rigid component that is inserted into the housing at the igniter-side axial end and gas-tightly connected to this end. The first rupture diaphragm, which seals the igniter cap gas-tight from the housing, is typically located at the other axial end of the igniter cap. In this design, the igniter is positioned radially inside the igniter cap. The igniter's electrical connections are usually accessible from the outside through an open end of the igniter cap.

[0021] In one version, the fuel tank is pre-filled with the fuel elements outside the gas generator and supplied as a complete sub-assembly, which is then inserted into the housing. This pre-assembly simplifies even filling of the fuel tank and reduces assembly time.

[0022] Inserting the fuel tank into the housing to its desired axial position can be simplified if the igniter-side axial end of the fuel tank is entirely formed by the gas inlet opening. The circumferential wall is then cylindrical in this area and forms the gas inlet opening at its igniter-side axial end without reducing the cross-sectional area. Accordingly, the fuel tank can be designed as an open, cylindrical tube at its igniter-side axial end, which also keeps manufacturing costs low.

[0023] In one possible embodiment, the circumferential wall of the fuel tank rests against the inside of the housing in sections, and the fuel tank is clamped to the inside of the housing by its circumferential wall. This creates a clamping connection between the fuel tank and the housing, reliably fixing the fuel tank within the housing without additional components, such as a groove on the inside of the housing, and without any additional manufacturing steps.

[0024] To easily achieve a high clamping force of the fuel tank within the housing, the tank's circumferential wall, for example, exhibits a certain degree of spring elasticity. This allows the circumferential wall to be pre-tensioned during insertion into the housing and pressed against the inside of the housing. This compensates for tolerances, for instance. Furthermore, because the fuel tank is supported against the inside of the housing, movement of the fuel tank relative to the housing caused by vehicle vibrations is prevented.

[0025] The clamping force can be easily determined by the geometric shape, diameter, and elasticity of the fuel container.

[0026] According to one aspect, the clamping connection is already created when the fuel tank is inserted into the housing.

[0027] The shock wave channel, i.e. the respective free space, can be defined, for example, by two circumferentially spaced sections of the circumferential wall adjacent to the inside of the housing.

[0028] The shape of the fuel tank's cross-section, perpendicular to the axial direction, allows for easy variation in the number, shape, and size of the spaces forming the shock wave channels. It is possible to create only a single space. However, for uniform shock wave propagation, two, three, four, five, or even up to twenty spaces have proven advantageous. Each space is then bounded by two sections of the circumferential wall abutting the inside of the housing. Alternatively, the space forming the shock wave channel can be created by a trough-shaped indentation in the fuel tank, where the circumferential wall of the fuel tank is offset radially from the outside to the inside within the indentation. The space(s) can thus be easily and precisely adapted to the specific requirements.

[0029] For example, the fuel tank might have only a single indentation and a crescent-shaped cross-section. Alternatively, there could be multiple indentations distributed around the circumference, with the sections between the indentations following a circular cylindrical contour. Another example is a cylinder with a corrugated or zigzag-shaped circumferential wall. This is a cost-effective way to manufacture the fuel tank from a cylindrical tube.

[0030] In another variant, the fuel tank has a polygonal cross-section perpendicular to the axial direction. For example, the cross-section can be triangular, square, pentagonal, or hexagonal. In this case, the fuel tank rests against the inside of the housing with the edges of its cross-section, automatically creating several gaps between the edges. Other non-circular cross-sections are also conceivable, such as an oval, star-shaped, or crescent-shaped profile.

[0031] In one possible design, the clamping force securing the fuel tank in the housing is so high that the fuel tank remains in its original position even when the gas generator is activated. Additional securing of the fuel tank within the housing may then be unnecessary.

[0032] In another possible variant, the clamping force is lower, allowing the fuel reservoir to be positioned in the housing in such a way that it can be moved axially within the housing after the gas generator is activated. The gas pressure in the fuel reservoir upon activation then becomes high enough to generate sufficient force to overcome the clamping force and move the fuel reservoir towards the diffuser-side end of the housing. This movement of the fuel reservoir reduces the gas flow over the fuel particles and the associated erosion. When the gas generator is activated, the fuel particles can move with the escaping gas and burn in a virtually flow-free environment before reaching the diffuser. This results in a more uniform and lower combustion rate.Furthermore, the shock wave is less attenuated when entering the fuel tank.

[0033] In this variant, a catcher in front of the diffuser, which retains fuel particles, can potentially be omitted, as this function can be performed by the fuel tank. Operationally induced movement of the fuel tank can also be prevented by a slight constriction of the gas generator housing. A constriction of <1% of the housing diameter immediately on the diffuser side of the fuel tank secures it within the housing.

[0034] In another possible embodiment, the fuel reservoir is firmly fixed to the igniter cap and normally remains firmly fixed to the igniter cap even after the gas generator is activated. Here, it is not necessary for the fuel reservoir to be additionally supported or clamped to the inside of the housing. The fuel reservoir is secured in the housing, for example, solely by fastening the igniter-side end of the fuel reservoir to the igniter cap.

[0035] In one variant, the fuel reservoir is attached to the igniter cap. The inner surface of the fuel reservoir's circumferential wall can rest against the outer surface of the igniter cap, ensuring precise radial alignment of the gas inlet opening. For example, the circumferential wall at the igniter-side end of the fuel reservoir runs parallel to the outer surface of the igniter cap in certain sections. This allows for easy definition of the dimensions and geometry of the clearance(s), as the igniter cap is positioned radially within the housing.

[0036] Since the igniter cap is radially spaced from the inside of the housing, a uniform radial distance between the fuel reservoir and the inside of the housing can easily be achieved, defining the clearance. In one possible design, the clearance is annular and surrounds the fuel reservoir circumferentially. The clearance can completely encircle the fuel reservoir and extend axially to the diffuser-side end of the fuel reservoir. This easily creates a sufficient radial distance between the fuel reservoir and the inside of the housing to quickly and without significant loss guide the shock wave axially through the housing to the second rupture diaphragm.

[0037] Since the pressurized gas can flow into the annular free space with little resistance, the filling time is also reduced. The heat generated during filling with pressurized gas can be dissipated more effectively via the housing, which in turn results in a lower adiabatic temperature rise.

[0038] Furthermore, the radial distance between the propellant particles in the fuel reservoir and the inside of the housing ensures that, for example, during a bonfire test, heat energy is transferred to the propellant particles more slowly, thus heating them more gradually. Therefore, the gas pressure in the pressurized gas rises relatively faster due to the heat input, and the housing is opened by the gas pressure before the propellant particles are fully combusted. Consequently, an additional pre-ignition device for the propellant particles may be unnecessary, reducing costs.

[0039] The fuel reservoir is permanently attached to the igniter cap, for example, via a press fit, a snap fit, and / or a crimp connection. Spot welding or laser welding is also possible. These methods easily create a sufficiently stable, positive-locking and / or friction-locking connection.

[0040] It is possible to design the igniter cap and the igniter-side end of the fuel container in such a way that the connection between the fuel container and the igniter cap is automatically formed directly when the fuel container is pushed onto the igniter cap.

[0041] In one variant, the edge of the fuel tank's gas inlet opening is bent radially inwards, at least in sections, and snapped into place on a radial shoulder on the igniter cap. If, for example, the edge of the gas inlet opening is spring-loaded and both the edge and the radial shoulder are suitably shaped, the edge of the inlet opening can initially deflect radially outwards and then snap back into place. This automatically creates a positive-locking connection when the fuel tank is placed on the igniter cap, securing the fuel tank to the igniter cap.

[0042] The radial shoulder on the outer surface of the igniter cap can be formed by one or more suitable structures on the outer surface, for example, projections and / or depressions, a circumferential groove, or a circumferential shoulder. The radial shoulder can also be formed by an edge of the first rupture membrane.

[0043] Additionally, a clamping ring can be inserted into the housing, radially surrounding the free edge of the inlet opening and applying radial pressure inwards to the free edge of the inlet opening. The clamping ring prevents, for example, radial expansion of the fuel tank when the gas generator is activated, ensuring that the fuel tank remains securely fixed to the igniter cap.

[0044] The clamping ring can also be arranged to surround the igniter cap and act on the edge of the inlet opening axially towards the diffuser-side axial end of the housing. In this case, the clamping ring presses the fuel reservoir against the radial shoulder on the igniter cap, thus holding the fuel reservoir in the desired position.

[0045] In another variant, a free edge of the fuel reservoir is reshaped by an additional component within the housing. This additional component is positioned in the housing such that the free edge comes into contact with it when the fuel reservoir is placed onto the igniter cap. The free edge automatically makes contact with the additional component when the fuel reservoir is inserted into the housing, provided the component is positioned in the area of ​​the igniter cap, for example, surrounding it. The additional component may have, for instance, a curved guide surface that bends the edge of the gas inlet opening radially inwards when the fuel reservoir is inserted.

[0046] The additional component is, for example, a rigid metal ring that is placed circumferentially around the igniter cap.

[0047] It is possible to insert the additional component into the housing before the fuel tank is inserted, or to slide the additional component into the housing after the fuel tank has already been placed on the igniter cap. The force applied when sliding either the fuel tank or the additional component into the housing serves to deform the free edge of the fuel tank between the outer surface of the igniter cap and the guide surface formed on the additional component.

[0048] The free edge can be crimped, folded over, or pressed into a groove on the outside of the igniter cap, for example. After forming, the free edge can be held in place by the radial shoulder on the igniter cap and thus fixed to it.

[0049] The additional component normally remains in the housing. Therefore, it can also serve as welding protection if the igniter cap is welded to the housing to protect the fuel body from heat.

[0050] According to another aspect, in addition to the gas-generating fuel bodies, at least one filling body made of a compressible, flammable foam can be arranged in the fuel tank.

[0051] This packing material typically consists of a non-pyrotechnic fuel. A suitable material is, for example, an open-cell, highly compressible melamine resin foam. Such a foam has an extremely low density, so it hardly affects the shock wave because virtually no moving mass needs to be accelerated. At the same time, this foam is resistant to aging and oxygen. Therefore, it can remain permanently inside the gas generator without significantly losing its structure or function. When the gas generator is activated, the packing material burns along with the fuel pellets without leaving any significant residue. The packing material also contributes to the energy balance and can assist in igniting the fuel pellets. Throughout the gas generator's lifespan, the packing material can also act as a volume compensator, preventing movement of the fuel pellets within the fuel container.

[0052] The packing material usually has a significantly larger volume than a single fuel particle. In one variant, the fuel reservoir is sealed at the diffuser-side axial end by only one packing material. This simplifies the manufacturing of the fuel reservoir, as it can be designed as a tube open at both ends. Before activation, the packing material, through its elasticity and clamping effect, securely holds the fuel particles in the fuel reservoir.

[0053] Multiple packing materials can also be arranged in the fuel tank, layered axially with the fuel particles. This allows the combustion characteristics to be influenced and the erosion of the fuel particles to be reduced.

[0054] Additionally or alternatively, a layer of polymeric fuel in the fuel reservoir can improve the ignition of the propellant pellets. Propellant pellets made entirely of polymeric fuel are also conceivable. The use of polymeric fuels improves the ignition behavior of the pyrotechnic propellant pellets without the ignition energy causing structural damage to the pellets. This results in controlled combustion and a defined burn-off.

[0055] The clamping ring and, if applicable, the additional component can optionally be made from one of the described non-pyrotechnic fuels.

[0056] In all embodiments and variants, it is not necessary to provide special geometries for the housing. The fuel reservoir is secured either by clamping it within the housing and / or by fixing it to the igniter cap. Therefore, on the igniter side, the housing can cost-effectively have a purely cylindrical shape, e.g., without any embossed grooves.

[0057] In all embodiments and variants, there is at least one clearance in which the circumferential wall of the fuel tank is radially spaced from the inside of the housing along its entire axial extent. The shock wave can propagate unhindered axially through this clearance, extending beyond the end of the fuel tank into the interior of the housing.

[0058] The invention is described in more detail below with reference to several exemplary embodiments and the accompanying figures. Figure 1 shows a schematic representation of a gas generator according to the invention;

[0059] Figure 2 shows a schematic sectional view of the gas generator according to the invention in a first embodiment;

[0060] Figures 3 to 6 show a fuel tank of the gas generator from Figure 2 according to a first variant in different views;

[0061] Figure 7 is a schematic sectional view of the gas generator from Figure 2 with a fuel tank from Figures 3 to 6;

[0062] Figure 8 shows a fuel tank of the gas generator from Figure 2 according to a further variant in a schematic perspective view;

[0063] Figures 9 and 10 show the fuel tank from Figure 8 inserted into the gas generator from Figure 2 in a longitudinal and a cross-sectional view;

[0064] Figure 11 shows a fuel tank of the gas generator from Figure 2 according to a further variant in a schematic perspective view;

[0065] Figures 12 and 13 show the fuel tank from Figure 11 inserted into the gas generator from Figure 2 in a schematic longitudinal and a schematic cross-sectional view;

[0066] Figure 14 shows a fuel tank of the gas generator from Figure 2 according to a further variant in a schematic perspective view;

[0067] Figures 15 and 16 show the fuel tank from Figure 14 inserted into the gas generator from Figure 2 in a schematic longitudinal and a schematic cross-sectional view;

[0068] Figure 17 shows a schematic representation of a flattened section of the fuel tank from Figure 14; Figure 18 shows a fuel tank of the gas generator from Figure 2 according to a further variant in a schematic perspective view;

[0069] Figures 19 and 21 show the fuel tank from Figure 18 inserted into the gas generator from Figure 2 in a schematic longitudinal and a schematic cross-sectional view;

[0070] Figure 20 is a schematic representation of a flattened section of the fuel tank from Figure 18;

[0071] Figures 22 to 25 are schematic views of a fuel tank of the gas generator from Figure 2 according to another variant;

[0072] Figures 26 and 27 show a schematic cross-sectional view and a schematic longitudinal section view of the fuel tank from Figures 22 to 24;

[0073] Figure 28 shows a schematic sectional view of a gas generator according to a second embodiment of the invention;

[0074] Figures 29 and 30 are schematic views of a fuel tank of the gas generator from Figure 28;

[0075] Figure 31 shows a schematic cross-sectional view of the gas generator from Figure 28 with the fuel tank of Figures 29 and 30;

[0076] Figure 32 shows a variant of the gas generator from Figure 28 with a clamping ring;

[0077] Figure 33 shows another variant of the gas generator from Figure 28 with a clamping ring;

[0078] Figure 34 is a schematic perspective representation of the clamping ring from Figures 32 and 33;

[0079] Figure 35 shows a schematic representation of an assembly consisting of a housing of the gas generator from Figure 28, a fuel tank and an igniter cap; Figures 36 to 38 show schematic longitudinal sectional views of the components from Figure 35;

[0080] Figures 39 to 43 are schematic perspective representations of variants of the fuel tank from Figures 32 and 33;

[0081] Figures 44 to 48 show a schematic representation of a further assembly consisting of a housing of the gas generator from Figure 28, a fuel container with a clamping ring and an igniter cap, in which the fuel container is fixed to the first burst membrane;

[0082] Figures 49 and 50 show the steps of fixing a fuel container of the gas generator from Figure 28 to the igniter cap according to another variant;

[0083] Figure 51 shows an enlarged section of Figure 50;

[0084] Figure 52 is a schematic longitudinal section view of the igniter cap from Figures 49 and 50;

[0085] Figures 53 and 54 show the steps of fixing a fuel container of the gas generator from Figure 28 to an igniter cap according to another variant;

[0086] Figure 55 shows an enlarged section of Figure 54;

[0087] Figure 56 is a schematic longitudinal section view of the igniter cap from Figures 53 and 54;

[0088] Figures 57 to 60 show the steps of fixing a fuel container of the gas generator from Figure 28 to an igniter cap according to another variant;

[0089] Figures 61 and 62 show the steps of fixing a fuel container of the gas generator from Figure 28 to an igniter cap with an additional component, according to another variant;

[0090] Figure 63 shows an enlarged section of Figure 62; and

[0091] Figure 64 shows a schematic longitudinal section view of the igniter cap from Figures 61 and 62. For the sake of clarity, not all identical components are always labelled.

[0092] Figures 1 and 2 show a gas generator 10, more specifically a hybrid gas generator, with a tubular housing 12 elongated along an axial direction A. At an igniter-side axial end 14 of the housing 12, the housing 12 is gas-tightly sealed by an igniter cap 16. The cup-shaped igniter cap 16 includes a central cavity into which an igniter 18 is inserted and fixed to the housing 12 in a known manner. Electrical connections 19 of the igniter 18 are accessible from the outside at the igniter-side end 14 of the housing 12.

[0093] The igniter cap 16 projects into the housing 12 and is gas-tightly sealed at its end facing away from the igniter-side axial end 14 by a first bursting membrane 20. The first bursting membrane 20 bursts upon activation of the gas generator 10 and generates a shock wave 21 in a known manner, which propagates through the housing 12 in axial direction A.

[0094] At a diffuser-side axial end 22 of the housing 12, opposite the igniter-side axial end 14, there is a diffuser 24 with several gas outlet openings 25 through which the gas generated by the gas generator 10 leaves the gas generator 10. At the diffuser-side axial end 22, the housing 12 is gas-tightly sealed by a second bursting membrane 26 before the gas generator 10 is activated.

[0095] The housing 12 is filled in a known manner between the first and the second burst diaphragm 20, 26 with a suitable pressurised gas 28.

[0096] At the igniter-side axial end 14, a fuel reservoir 30 is inserted into the housing 12. The fuel reservoir 30 has a circumferential wall 32 that surrounds an interior space 34. A plurality of known pyrotechnic propellant elements 36 are accommodated in the interior space 34. The fuel reservoir 30 has a gas inlet opening 40 at its igniter-side free end 38 (see also Figures 3 to 27, which show different versions of the fuel reservoir 30).

[0097] The gas inlet opening 40 faces the igniter 18 and the first rupture membrane 20. In Figure 2, the fuel reservoir 30 also contains two packing elements 42 made of a suitable material, which are, for example, layered alternately with the fuel elements 36 or arranged at the igniter-side axial end 38 and / or at the opposite diffuser-side axial end 48 of the fuel reservoir 30. In all the variants described below, such packing elements 42 may be present or omitted. The packing elements 42 are described in more detail below.

[0098] The circumferential wall 32 of the fuel tank 30 has a plurality of flow openings 50.

[0099] For example, at least the perimeter wall 32 is made of perforated sheet metal or expanded metal.

[0100] In general, all flow openings 50 can have the same shape and size, but they can also be designed differently. In one variant, the flow openings 50 are evenly distributed across the perimeter wall 32; however, the distribution can optionally be uneven.

[0101] In the examples shown here, the igniter-side axial end 38 of the fuel reservoir 30 is completely formed by the gas inlet opening 40.

[0102] The fuel reservoir 30 is pushed over the igniter cap 16 with its igniter-side axial end 38, such that the igniter-side axial end 38 overlaps the igniter cap 16 axially. In this embodiment, there is a radial gap between an outer surface 52 of the igniter cap 16 and the circumferential wall 32.

[0103] The circumferential wall 32 is shaped such that the fuel tank 30 rests against an inner surface 54 of the housing 12.

[0104] Radially between the inner surface 54 of the housing 12 and the circumferential wall 32, at least one free space 56 is formed. At least one of the flow openings 50 forms a permanent flow connection between the interior 34 of the fuel tank 30 and the free space 56. The free space 56 extends continuously to the diffuser-side axial end 48 of the fuel tank 30 and transitions directly into an interior 58 of the housing 12. The free space 56 thus forms a shock wave channel for the shock wave 21, which is permanently open towards the diffuser-side axial end 22 of the housing 12.

[0105] The interior 34 of the fuel tank 30 is in permanent flow communication with the interior 58 of the housing 12 via the flow openings 50 and the free spaces 56.

[0106] Accordingly, there is also pressurized gas inside the fuel tank 30, which surrounds the individual fuel bodies 36.

[0107] In the variants shown in Figures 3 to 27, several sections 60 of the circumferential wall 32 abut the inner side 54 of the housing 12 (see, for example, Figure 7). A free space 56 is formed between each pair of sections 60 spaced apart in the circumferential direction U. Optionally, each free space 56 forms its own shock wave channel.

[0108] In the examples shown in Figures 3 to 27, the fuel tank 30 is clamped to the inside 54 of the housing 12. The fuel tank 30 may only be fixed to the housing 12 by this clamping connection.

[0109] In one variant, the clamping force is chosen to be so high that the fuel tank 30 remains fixed in its position in the housing 12 even when the gas generator 10 is activated.

[0110] In another variant, the fuel tank 30 is displaceable in axial direction A towards the diffuser 24 within the housing 12 upon activation of the gas generator 10 by the gas pressure generated during the combustion of the fuel elements 36 and by the shock wave 21. The clamping force of the fuel tank 30 within the housing 12 must, of course, be selected to be high enough that the fuel tank 30 does not move relative to the housing 12 during normal vehicle movements prior to activation of the gas generator 10.

[0111] Each of the free spaces 56 extends completely open in axial direction A towards the diffuser-side axial end 22 of the housing 12, and, most importantly, without any propellant body 36 or packing material 42, and also without any other obstructions, up to the diffuser-side axial end 48 of the propellant reservoir 30, and then transitions openly into the interior 58 of the housing 12. When the gas generator 10 is activated by igniting the igniter 18 via its electrical connections 19, the igniter 18 releases gas and / or hot particles, and a gas pressure builds up that abruptly opens the first rupture membrane 20. This results in the shock wave 21 in a known manner.

[0112] The shock wave 21 initially enters the fuel tank 30 in axial direction A through the gas inlet opening 40. A portion of the shock wave 21 enters the free spaces 56 through the flow openings 50 and is deflected again in axial direction A within the free spaces 56, so that the shock wave 21 also passes through the free spaces 56 in axial direction A. Since the free spaces 56 are free of flow obstructions, the shock wave 21 propagates axially through the free spaces 56 with only minimal flow resistance and continues unimpeded to the diffuser-side end 22 of the housing 12, where it reaches the second rupture diaphragm 26 with sufficient force to open it.

[0113] The shock wave channels formed by the free spaces 56 thus allow the shock wave 21 to largely bypass the fuel tank 30.

[0114] Even though the fuel tank 30 is axially displaceable within the housing 12, the free spaces 56 remain completely open during the displacement movement, thus maintaining the respective shock wave channel at all times. The shock wave 21 can therefore always move axially in the free spaces 56 past the fuel tank 30, so that a portion of the shock wave 21, largely bypassing the fuel tank 30, enters the interior 58 of the housing 12 on the diffuser side of the fuel tank 30.

[0115] Figures 3 to 7 show a variant in which the fuel reservoir 30 is designed as a cylindrical tube, which is closed at the diffuser-side axial end 48 by a cover 62 (see Figure 6). At the igniter-side axial end 38, the tube is open and forms the gas inlet opening 40 over its entire cross-sectional area (see Figure 5).

[0116] At least the circumferential wall 32, optionally the entire fuel tank 30, has a large number of flow openings 50.

[0117] In this example, the cross-section of the circumferential wall 32 does not change along the longitudinal extent of the fuel tank 30. The circumferential wall 32 of the fuel tank 30 is provided along its entire axial length with several, here a total of six, channel-shaped indentations 64 evenly distributed in the circumferential direction U. Each of the indentations 64 forms a free space 56 and thus a shock wave channel.

[0118] The number of indentations 64 is variable at the discretion of the person skilled in the art; for example, only a single indentation 64 could be provided, or the number of indentations 64 could be, for example, between two and twenty.

[0119] It is possible to emboss the indentations 64 into the circumferential wall 32. On either side of each indentation 64, a section 60 is formed against which the circumferential wall 32 abuts the inner side 54 of the housing 12. The sections 60 define the free spaces 56 and simultaneously clamp the fuel tank 30 in the housing 12 (see Figure 7).

[0120] Figures 8 to 10 show another variant of a fuel tank 30. Here, the entire fuel tank 30 is optionally made of perforated sheet metal. In this variant, the lid 62 is also provided with flow openings 50.

[0121] The individual free spaces 56 are formed, as in the previous example, by channel-shaped indentations 64 in the perimeter wall 32. A total of eight indentations 64 are formed here.

[0122] The fuel reservoir 30 is pot-shaped and tapers slightly from its igniter-side axial end 38 to its diffuser-side axial end 48.

[0123] Due to the radial narrowing along the axial direction A, the free spaces 56, which form the shock wave channels, widen radially towards the diffuser-side axial end 22 of the housing 12 and transition to an annular space towards the axial end 48 of the fuel tank 30, which completely surrounds the fuel tank 30 in the circumferential direction U.

[0124] Figures 9 and 10 show the fuel tank 30 inserted into the housing 12 and the resulting free spaces 56, which represent the shock wave channels. Figures 11 to 13 show another variant of a fuel tank 30.

[0125] Here, the fuel tank 30 is formed from a circular cylindrical tube, for example from a perforated sheet, wherein the diffuser-side axial end 48 is laterally compressed at three points, so that the diffuser-side axial end 48 (with the exception of the flow openings 50) is largely closed.

[0126] In this example, a total of three indentations 64 are formed in the circumferential wall 32, which form the free spaces 56 and thus the shock wave channels (see Figure 13).

[0127] Figures 14 to 16 show another variant of a fuel tank 30. In this example, the fuel tank 30 has a square cross-section perpendicular to the axial direction A and is closed at one end by a lid 62.

[0128] The fuel tank 30 is inserted into the housing 12 such that its edges 66 are clamped to the inner surface 54 of the housing 12. Optionally, the edges 66 are relatively sharp, ensuring sufficient grip on the inner surface 54 of the housing 12 and thus reliably preventing movement of the fuel tank 30 before the gas generator 10 is activated.

[0129] Accordingly, the spaces 56, and thus the shock wave channels, are formed between the side faces of the square cross-section and the inner surface 54 of the housing 12 (see Figure 16). The edges 66 therefore form the sections 60 that abut the inner surface 54 of the housing 12 between the shock wave channels.

[0130] The fuel tank 30 is manufactured here from a single piece, e.g., from a perforated sheet, as illustrated in Figure 17. The side surfaces are optionally connected at the edges 66.

[0131] Figures 18 to 21 show another variant of a fuel tank 30. Here, the cross-section is chosen to be in the form of an equilateral triangle, perpendicular to the axial direction A. Otherwise, the design corresponds to the variant just described.

[0132] Other polygonal cross-sections of the fuel tank 30 are of course also conceivable.

[0133] Figures 22 to 27 show another variant of a fuel tank 30. In this example, the fuel tank 30 is formed by a cylindrical tube made of perforated sheet metal, open at both ends, the cross-section of which does not change along the axial direction A. The circumferential wall 32 is corrugated, here with a serrated shape, so that in cross-section perpendicular to the axial direction A, a star shape with a multitude of points is formed, between which the indentations 64 and thus the free spaces 56 are formed (see, for example, Figure 26). The free spaces 56 are formed between the individual serrations.

[0134] Figure 25 shows that the fuel tank 30 in this example is made from a strip of corrugated perforated sheet metal. The strip is wound up, with the free ends 67 of the strip overlapping along the circumferential direction U. Optionally, these ends 67 are fixed together. If the ends 67 are simply overlapped, the inherent elasticity of the material automatically compensates for manufacturing tolerances between the cross-section of the fuel tank 30 and the cross-section of the housing 12, so that the desired clamping force of the fuel tank 30 in the housing 12 is always achieved.

[0135] The cross-section shown in Figure 27 shows that the fuel container 30 is closed at both axial ends 38, 48 by a filling element 42, which holds the fuel bodies 36 in the interior 34 and secures them against movement.

[0136] The operating principle described for the first variant is identical for all variants shown here.

[0137] Naturally, the shape, size, and arrangement of the flow openings 50 can be varied at the discretion of the person skilled in the art and optimized for the respective application. It is also possible to vary the density, size, and shape of the flow openings 50 at different locations on the fuel tank 30 in order to achieve the desired gas flow and also the desired steering of the shock wave from the interior 34 of the fuel tank 30 into the free spaces 56. However, the flow openings 50 are always arranged such that each free space 56 is in flow communication with the interior 34 of the fuel tank 30 via at least one flow opening 50.

[0138] In these examples, the igniter-side axial end 38 of the fuel reservoir 30 extends parallel to the igniter cap 16, but is not in contact with its outer surface 52.

[0139] In all the examples described, the fuel reservoir 30 is optionally filled with the fuel elements 36 and, if necessary, packing elements 42 outside the housing 12 (see, for example, Fig. 22). This prefabricated assembly 68 is then inserted as a whole into the housing 12 up to the desired position at the igniter-side axial end 14 of the housing 12, so that the igniter-side axial end 38 overlaps with the igniter cap 16, as shown in Figure 2.

[0140] In the first embodiment, the fuel tank 30 is primarily fixed in these cases by a clamping force on the inside 54 of the housing 12. Further fastenings to the housing 12 and / or to the igniter cap 16 may be omitted.

[0141] In general, in each variant, one or more packing elements 42 can be present in any position in the fuel tank 30.

[0142] In one possible variant, at least one of the packing elements 42 consists of a compressible, flammable foam with a very low density made from a non-pyrotechnic fuel. In this case, the packing element 42 burns virtually without residue during the activation of the gas generator 10, together with the pyrotechnic propellant elements 36. A suitable material would be, for example, an open-cell, highly compressible melamine resin foam.

[0143] Before the gas generator 10 is activated, the packing element 42 serves as an elastic compensating element, compensating for volume changes in the fuel bodies 36 and protecting them from erosion caused by movement within the fuel container 30 through an elastic clamping force. Figures 28 to 64 show a second embodiment of the gas generator 10. Since the main difference lies in the mounting of the fuel container 30 in the housing 12, the reference numerals used previously for at least substantially identical or equivalently functioning components are retained for the sake of clarity.

[0144] In this embodiment of the gas generator 10, the igniter-side axial end 38 of the fuel container 30 is fixed directly to the igniter cap 16.

[0145] In all variants shown in Figures 28 to 64, the fuel container 30 remains fixed to the igniter cap 16 even during the activation of the gas generator 10.

[0146] The free space 56 results here as an annular space radially outside the fuel tank 30 between the fuel tank 30 and the inner side 54 of the housing 12.

[0147] As in the previous embodiment with the variants of Figures 2 to 27, the shock wave 21 enters axially into the fuel container 30 after the first burst membrane 20 is destroyed by the igniter 18, then partially enters the free space 56 through the flow openings 50 in the circumferential wall 32 of the fuel container 30 radially or obliquely to the diffuser-side axial end 22 of the housing 12 and spreads in the free space 56, which acts as a shock wave channel, along the axial direction A towards the diffuser-side axial end 22 of the housing 12 and to the second burst membrane 26 and opens it.

[0148] As in the first embodiment, the free space 56 is completely free of obstructions, i.e., free of propellant bodies 36, packing materials 42, and other obstructions. The operating principle of the gas generator 10 and of the free space 56, which serves as a shock wave channel, is identical to the first embodiment.

[0149] The fuel reservoir 30 is attached to the igniter cap 16, for example, by means of a press connection, a snap connection, a crimp connection, by welding and / or by gluing.

[0150] Figures 28 to 31 show a variant in which the fuel reservoir 30 with the igniter-side axial end 38 sits directly on the outer side 52 of the igniter cap 16, thus completely surrounding the outer side 52 and directly abutting it.

[0151] The fuel reservoir 30 can be fixed to the igniter cap 16, for example, purely by a clamping action. However, alternative or additional fastening methods, such as welding or gluing, are also conceivable.

[0152] Perpendicular to the axial direction A, the fuel reservoir 30 has a circular cross-section both at the igniter-side axial end 38 and during its further axial extension, which corresponds to the diameter of the outer surface 52 of the igniter cap 16.

[0153] At the diffuser-side axial end 48, the fuel tank 30 is closed analogously to the variant of the first embodiment shown in Figures 11 to 13, by compressing the circumferential wall 32 radially, here at four points, so that a lid 62 is formed.

[0154] Figures 32 to 43 show different variants in which the fuel container 30 is fixed at its free edge 70 at the igniter-side axial end 38 to the igniter cap 16 by a latching connection or a snap connection.

[0155] As can be seen, for example, in Figures 32 to 34, in one variant the edge 70, which also forms the edge of the gas inlet opening 40, is bent radially inwards, so that a radially elastic locking element or several radially elastic locking hooks distributed over the circumferential direction U are formed.

[0156] When the fuel container 30 is pushed into the housing 12 along the axial direction A in the direction of the igniter cap 16, the rim 70 engages behind a radial shoulder 72 formed on the outer surface 52 of the igniter cap 16 (clearly visible, for example, in Figure 43). In this way, the fuel container 30 is secured to the igniter cap 16.

[0157] The radial shoulder 72 can be formed, for example, from individual projections radially extending from the outer surface 52 or from a circumferential continuous projection (see Figure 40), but also by limiting surfaces of one or more recesses, for example on a circumferential groove.

[0158] Figure 32 shows a variant in which an elastic clamping ring 74 (see also Figure 34) is provided to secure the connection between the fuel reservoir 30 and the igniter cap 16. The clamping ring 74 is first inserted into the housing 12 so that it radially surrounds the igniter cap 16. The clamping ring 74 is thus located closer to the igniter-side axial end 14 of the housing 12 than the igniter-side axial end 38 of the fuel reservoir 30.

[0159] When the fuel container 30 is inserted into the housing 12, the clamping ring 74 is slightly compressed by the igniter-side axial end 38 of the fuel container 30 until the rim 70 engages behind the radial shoulder 72. When the axial force with which the fuel container 30 is inserted into the housing 12 ceases, the clamping ring 74 expands axially again, thus constantly holding the rim 70 pressed against the radial shoulder 72 and permanently securing the fuel container 30 to the igniter cap 16. The inner diameter d of the clamping ring 74 corresponds approximately to the outer diameter of the outer surface 52 of the igniter cap 16.

[0160] Figure 33 shows a variant in which the clamping ring 74 is inserted into the housing 12 after the fuel reservoir 30 has already been snapped onto the igniter cap 16. The clamping ring 74 is pushed over the circumferential wall 32 of the fuel reservoir 30 and clamped between the circumferential wall 32 and the inner surface 54 of the housing 12. Thus, the clamping ring 74 exerts a radially inward force on the igniter-side axial end 38 of the fuel reservoir 30, pressing the rim 70 against the outer surface 52 of the igniter cap 16. In this way, the fuel reservoir 30 is permanently secured to the igniter cap 16. The inner diameter d of the clamping ring 74 therefore corresponds approximately to the outer diameter of the circumferential wall 32 of the fuel reservoir 30.

[0161] Figure 35 and Figures 36 to 38 show the housing 12, the igniter cap 16 and the fuel reservoir 30 before the fuel reservoir 30 is installed in the housing 12. It is conceivable that the clamping ring 74, analogous to the packing elements 42, consists of a non-pyrotechnic fuel.

[0162] Figures 39 to 43 show different variations of how the rim 70 of the gas inlet opening 40 can be designed to form a latching or snap-fit ​​connection with the igniter cap 16. In these examples, the rim 70 is interrupted at least at two points, forming individual latching hooks. The latching hooks are either practically directly adjacent to each other in the circumferential direction U (Figures 39, 40) or spaced apart from each other (Figures 41 to 43). Other geometric designs that result in a latching or snap-fit ​​connection are, of course, also conceivable.

[0163] Another variant is shown in Figures 44 to 48. Here, the fuel container 30 is locked onto the first rupture diaphragm 20. For this purpose, as described in the previous variants, the edge 70 of the gas inlet opening 40 is bent radially inwards and forms one or more locking hooks that engage behind a free edge 76 of the first rupture diaphragm 20 when the fuel container 30 is inserted into the housing 12.

[0164] Here, a clamping ring 74 is also provided, which, analogous to the variant shown in Figure 33, is pushed around the igniter-side axial end 38 of the fuel reservoir 30 and permanently presses radially inwards against the bent edge 70 of the gas inlet opening 40. In this way, the connection between the fuel reservoir 30 and the burst membrane 20, and thus the igniter cap 16, is permanently secured.

[0165] In these variants, as already described in the first embodiment, the fuel container 30 can be filled with the fuel bodies 36 and optionally the packing bodies 42 outside the housing 12 and inserted into the housing 12 as a complete assembly 68 and fixed to the igniter cap 16.

[0166] The described variants can also be implemented without an additional clamping ring 74. In this case, the edge 70 of the gas inlet opening 40 of the fuel reservoir 30 may need to be designed with greater dimensional stability. Figures 49 to 52 show another variant for fixing the fuel reservoir 30 to the igniter cap 16.

[0167] Here, the edge 70 of the gas inlet opening 40 at the igniter-side axial end 38 of the fuel reservoir 30 is bent radially inwards by a suitable tool and pressed into a groove 78 which is formed circumferentially in the outer surface 52 of the igniter cap 16.

[0168] The surface of the groove 78 facing the igniter-side axial end 14 of the housing 12 forms the radial shoulder 72 on which the edge 70 of the gas inlet opening 40 of the fuel tank 30 is secured (see, for example, Figure 51).

[0169] Another variant is shown in Figures 53 to 56. In contrast to the variant just described, the edge 70 is not bent over by an external tool, but rather the edge 70 of the gas inlet opening 40 of the fuel reservoir 30 is automatically bent radially inwards by a rounded guide surface 80 of the groove 78 when inserted along the axial direction A onto the igniter cap 16. For this purpose, the guide surface 80 of the groove 78, which points away from the axial end 14 of the housing 12 on the igniter side, is provided with a curve.

[0170] On the outer surface 52 of the igniter cap 16, a radially projecting projection is formed around the circumference, which limits the groove 78 and whose surface facing the igniter-side axial end 14 of the housing forms the radial shoulder 72, which the bent edge 70 engages behind.

[0171] Figures 57 to 60 show a similar variant. Here, the outer surface 52 of the igniter cap 16 has no additional projection. The radial shoulder is formed by the edge of the groove 78, which meets the axial end 14 of the housing 12 on the igniter side. The groove 78 has an overall rounded cross-section, which guides the edge 70 when the fuel reservoir 30 is inserted and simultaneously bends it radially inwards. This process is illustrated in the sequence of Figures 57 to 60.

[0172] Figures 61 to 64 show a variant in which a rigid additional component 82 is inserted into the housing 12 to radially reshape the edge 70 of the gas inlet opening 40 at the igniter-side axial end 38 of the fuel tank 30 in the desired manner.

[0173] In this case, the additional component 82 is inserted into the housing 12 before the fuel container 30 is inserted. The fuel container 30 is inserted into the housing such that the rim 70 of the fuel container 30 lies radially between the outer surface 52 of the igniter cap 16 and the inner surface of the additional component 82.

[0174] The additional component 82 is, for example, a sleeve with a slightly larger diameter than the circumferential wall 32 of the fuel container 30. At its igniter-side end, the sleeve has a rounded, radially inwardly projecting guide surface 84, pointing away from the igniter-side axial end 14 of the housing 12, against which the rim 70 abuts when the fuel container 30 is inserted into the housing 12. The insertion force guides the rim 70 along the surface 84 and bends it radially inward.

[0175] The additional component 82 remains in the housing 12 after assembly.

[0176] A suitable radial shoulder 72 is formed on the igniter cap 16 to retain the bent edge 70 of the fuel container 30 when the gas generator 10 is activated.

[0177] In all the examples described, as described above, the fuel reservoir 30 is optionally filled with the fuel bodies 36 and, if necessary, packing bodies 42 outside the housing 12, and this pre-assembled unit 68 is then inserted as a whole into the housing 12, whereby the rim 70 of the fuel reservoir 30 is fixed to the igniter cap 16 in a suitable manner.

[0178] All features of the individual embodiments and variants can be freely interchanged or combined at the discretion of a person skilled in the art. In particular, the fuel reservoir 30 can generally be designed with a circumferential wall 32 that is clamped section by section in the housing 12, but tapers towards the diffuser-side axial end 48 of the fuel reservoir 30, so that an annular free space 56 is formed as a shock wave channel. Conversely, it would also be possible to design the circumferential wall 32 of the fuel reservoir 30 such that it rests at least largely against the inner surface 54 of the housing 12, but has channel-shaped indentations that form the free spaces and thus the shock wave channels, while the igniter-side axial end 38 of the fuel reservoir 30 is firmly and permanently fixed to the igniter cap 16 via one of the described connections.

Claims

Patent claims 1. Gas generator (10) with a tubular housing (12) filled with a pressurized gas (28) and having at an igniter-side axial end (14) an igniter (18) received in an igniter cap (16) and at an opposite diffuser-side axial end (22) a diffuser (24) with at least one gas outlet opening (25), and with a fuel container (30) filled with gas-generating fuel elements (36) arranged inside the housing (12), wherein the fuel container (30) has a circumferentially closed circumferential wall (32) with a plurality of flow openings (50), and an interior space (34) of the fuel container (30) and at least a free space (56) formed radially between the circumferential wall (32) and an inner surface (54) of the housing (12) via the circumferential wall (32) in the non-activated and in the activated state of the gas generator (10) are permanently in flow contact,and the fuel container (30) has a gas inlet opening (40) at an igniter-side axial end (38) through which a shock wave (21) enters the fuel container (30) when the gas generator (10) is activated, wherein the at least one free space (56) forms a shock wave channel permanently open towards the diffuser-side end (22) of the housing (12) for the shock wave (21) which passes through the circumferential wall (32).

2. Gas generator (10) according to claim 1, wherein a first bursting membrane (20) is arranged on the igniter cap (16), which bursts when the igniter (18) is activated and generates the shock wave (21).

3. Gas generator (10) according to one of the preceding claims, wherein the free space (56) widens towards the diffuser-side end (22) of the housing (12).

4. Gas generator (10) according to one of the preceding claims, wherein the fuel reservoir (30) with its gas inlet opening (40) axially overlaps the igniter cap (16).

5. Gas generator (10) according to one of the preceding claims, wherein the circumferential wall (32) of the fuel container (30) abuts the inside (54) of the housing (12) in sections and the fuel container (30) is clamped to the inside (54) of the housing (12) with the circumferential wall (32).

6. Gas generator (10) according to claim 5, characterized in that the shock wave channel is bounded by two sections (60) of the circumferential wall (32) spaced apart in the circumferential direction (U) and abutting the inside (54) of the housing (12).

7. Gas generator (10) according to one of the preceding claims, wherein the free space (56) forming the shock wave channel is formed by a trough-shaped indentation (64) in the fuel container (30).

8. Gas generator (10) according to one of the preceding claims, wherein the fuel tank (30) has a polygonal cross-section perpendicular to the axial direction (A).

9. Gas generator (10) according to one of the preceding claims, wherein the fuel container (30) is arranged in the housing (12) such that the fuel container (30) is displaceable in the axial direction (A) in the housing (12) after activation of the gas generator (10).

10. Gas generator (10) according to any one of claims 1 to 8, wherein the fuel container (30) remains firmly fixed to the igniter cap (16) after activation of the gas generator (10).

11. Gas generator (10) according to claim 10, wherein the free space (56) is annular and circumferentially surrounds the fuel container (30).

12. Gas generator (10) according to claim 10 or claim 11, wherein the fuel reservoir (30) is permanently attached to the igniter cap (16) via a press connection, a snap connection and / or a crimp connection.

13. Gas generator (10) according to one of claims 10 to 12, wherein a free edge (70) of the gas inlet opening (40) of the fuel container (30) is at least partially bent radially inwards and locked onto a radial shoulder (72) on the igniter cap (16).

14. Gas generator (10) according to claim 12 or claim 13, wherein a free edge (70) of the fuel container (30) is formed by an additional component (82) in the housing (12), the additional component (82) being arranged in the housing (12) such that the free edge (70) comes into contact with the additional component (82) when the fuel container (30) is placed on the igniter cap (16).

15. Gas generator (10) according to any one of the preceding claims, wherein, in addition to the gas-generating fuel bodies (36) in the fuel container (30), at least one filling element (42) made of a compressible, flammable foam is arranged.

16. Gas generator (10) according to claim 15, wherein the fuel reservoir (30) at the diffuser-side axial end (48) is closed only by the at least one filling body (42).

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