DE102008022342A1 - Airbag module used for motor vehicle, has airbag which is inflatable with gas to protect occupant, gas generator for generating gas provided for inflating airbag and additional cooling device with reservoir for storing coolant - Google Patents

Abstract

An airbag module (1) has an airbag (2) which is inflatable with a gas to protect an occupant, a gas generator (3) for generating the gas provided for inflating the airbag and an additional cooling device (5) with a reservoir for storing a coolant (K), and the reservoir is designed to be opened such that the coolant contacts the gas used to inflate the airbag and cools the gas. The coolant contains a cooling substance such as monohydric alcohol, polyhydric alcohol, ester, ether, alkane, alkene, alkyne and/or blended or unblended mineral, partially synthetic oil. An independent claim is included for method of cooling gas used to inflate airbag in the air module.

Description

The The invention relates to an airbag module for a motor vehicle According to the preamble of claim 1, a method for cooling a for inflating a gas bag in an airbag module for a motor vehicle used gas by means of a coolant according to the The preamble of claim 11 and the use of various Substances as cooling substances in a coolant according to claim 12.

From the DE 10 2006 010 953 A1 An airbag module is known in which a coolant is used in a cooling device for cooling a gas to be used for inflating a gas bag. However, the coolant is not specified in more detail.

From the WO 2007/141 335 A1 a gas generator with integrated cooling device is known in which glycol (ethylene glycol, 1,2-ethanediol) is used as a coolant. However, 1,2-ethanediol has unfavorable toxicological properties.

From the DE 22 36 380 A1 For example, the use of water and aqueous solutions of salts as coolants in gas generators is known.

From the DE 21 53 639 A1 Furthermore, the use of liquid halogenated hydrocarbons such as freon 11 (trichlorofluoromethane) and freon 12 (dichlorodifluoromethane) is known. However, halogenated hydrocarbons have unfavorable environmental properties.

Of the The present invention is based on the object, an airbag module for a motor vehicle, in which a coolant with favorable toxicological properties and favorable Environmental features are used.

These Task is with an airbag module with the features of the claim 1 solved. Such an airbag module for a motor vehicle has an airbag inflatable to protect an occupant with gas is. Furthermore, in the airbag module, a gas generator for generating the for inflating the gas bag provided gas and an additional Cooling device provided which a reservoir for storing a coolant. The reservoir can be opened be, for. B. at or after inflation of the airbag, so that the coolant for cooling the to inflate the Gas bag used gas can come into contact with this.

According to the invention the coolant has at least one cooling substance, as a cooling substance monohydric alcohols (monools) and / or polyhydric alcohols (polyols having three or more hydroxyl groups carry) and / or esters and / or ethers and / or alkanes and / or alkenes and / or alkynes and / or mineral or semi-synthetic or synthetic oils can be. The oils can be in alloy or unalloyed form. Alloyed oils are also called called additive oils, that is, they are mixed with one or more additives. It is also possible that the alkanes, alkenes and / or alkynes are replaced by one or more oxygen, Substituted nitrogen atoms and / or sulfur atoms and / or interrupted could be. The coolant can be any Combination of the aforementioned cooling substances. It is also within the scope of the present invention, individual of the aforementioned Do not use substances as cooling substance, so that itself as a cooling substance for the coolant reduce the substances to be used to a correspondingly lower number. In particular, it is also provided, in addition to the cooling substance water as a further cooling substance to use, that is, a mixture of water and at least one other cooling substance to be used as coolant.

In order to the use of the coolant harmless possible In one variant, the cooling substance has such properties on that inhalation of the cooling substance, for example when the coolant containing the cooling substance evaporates is toxicologically harmless by a motor vehicle occupant is. By a corresponding evaporation of the coolant Consequently, from the cooling substance no form toxic compounds. Also may the cooling substance do not already have toxic properties on their own. Inhaling the cooling substance or the coolant can then be considered as toxicologically safe, if by the legislator or an interest group or similar Association prescribed limits not exceeded become.

In a variant, the coolant additionally at least one additive to the cooling substance. The additive may be an emulsifier or a surfactant or a foam inhibitor or a substance for freezing point depression or a substance for Reduction of fog prevention during evaporation of the coolant or a biocide. Mixtures of the aforementioned Additives are also conceivable. The additive can also be made from a Group selected, which is a sub-combination of the previously represents the substance classes or the substances that fall within it. Suitable substances for freezing point depression are sugar or Sugar substitutes. Examples include sucrose, sorbitol, Xylitol, maltitol, lactitol, isomalt, fructose, erythritol, cyclamate, glucose and acesulfame K. Examples of biocides are fungicides, Bactericides, algicides, microbicides and virucides.

In a further embodiment, the coolant additionally to the refrigerant to a gas in dissolved form. This makes it possible at an opening of the Reservoirs that stores the coolant, and at a concomitant change in pressure on the coolant acts, outgassing dissolved in the coolant To reach gas. Further, by a temperature increase of the coolant as a result of the cooling process the gas used to inflate the airbag another physical Possibility created a gassing of in dissolved To achieve the form contained in the coolant gas. there can the outgassing of the previously dissolved in the coolant gas suddenly or suddenly, so that there is a turbulence of the coolant. This requires a better distribution of the coolant and thus a more effective cooling of the to inflate the Airbag used gas. That is, a metastable Condition of the coolant due to the presence of a light Ausgasbaren gas in dissolved form is an embodiment of Invention provided.

In one variant, the gas present in dissolved form in the coolant is carbon dioxide (CO ₂ ).

Around a particularly effective cooling of the to inflate the Gas bag used to reach gas is the coolant in one embodiment, substantially liquid at room temperature. It can be used, for example, as a solution, emulsion or dispersion available. Also, a liquid substance is as a coolant provided in the context of the present invention. To have a good availability of the To allow coolant under steady conditions is the coolant whenever it comes from a mixture consists of more than one substance, designed such that the individual components of the coolant do not segregate. If the coolant contains, for example, water and oil, is the addition of an emulsifier or surfactant for maintenance a stable emulsion of the oil in water is advantageous, to counteract a segregation of the two substances. By suitable additives can be a stable storable coolant to be provided. Certain substances in any proportions are miscible with each other, do not need additives to one Counteract segregation of these substances. This depends from the respective individual properties of the as cooling substances from substances to be used.

If the coolant is in liquid form, evaporates when in contact with the hot, to inflate the airbag used gas. By the transition from the liquid in the gaseous state of matter is enthalpy of vaporization needed, which gives the hot gas a big Deprives you of energy. This way it comes to a special efficient cooling of the gas bag used to inflate Gas.

there it is advantageous if the coolant is in the range of about -40 ° C to about + 90 ° C (for individual applications also up to approx. + 107 ° C) liquid state of matter is present. Next to a freezing point the coolant of about -40 ° C is too a freezing point of about -38 ° C or below, in particular from about -35 ° C or below and especially from about -30 ° C or below.

As well is next to a boiling point of the coolant of about + 90 ° C also a boiling point of about + 95 ° C or above, in particular of about + 100 ° C or above, in particular of about + 105 ° C or above and especially from about + 107 ° C or above for that Coolant provided.

In In one variant, the cooling substance used has the same Freezing and boiling point on as the coolant. In this Fall must the phase transition points of the cooling substance then not be influenced by additives.

By a boiling point just above the upper limit of the temperature range, in which an application of the airbag module provided by default is (this is usually a temperature of about + 90 ° C), can be a particularly simple evaporation of the coolant When done with the one to be cooled, for the Inflating the gas bag used gas comes into contact. Lies the boiling point of the coolant, for example, between about 90 ° C and about 100 ° C, it comes in each Fall in contact with the hot, to inflate the airbag used gas to an evaporation of the coolant and thus to an energy extraction from the inflation of the airbag used gas.

In In one variant, the coolant is oxygen-excluded not flammable in the system. In another variant it is not flammable even if it is finely fogged and with hot gas used to inflate the airbag comes into contact. This gas is usually low in oxygen, which is why also numerous oils to be used in fine nebulization with the gas used to inflate the airbag as not are flammable.

In order to allow a particularly fine distribution of the coolant in the gas to be cooled, the coolant in one variant has a surface tension at + 20 ° C of less than or equal to 150 mN / m, in particular of less than or equal to 100 mN / m, in particular of less than or equal to 50 mN / m and especially of less than or equal to 25 mN / m.

In Another embodiment of the invention is the surface tension the coolant is lower than the surface tension pure Water in the same conditions. In this way will in any case, a lighter distribution of the coolant towards a distribution of pure water allows.

The The object underlying the invention is also achieved by a method for cooling a used for inflating a gas bag Gas with the features of claim 11 solved. At a Such a method is an airbag in an airbag module for a motor vehicle inflated by a gas, which by means of a Coolant contained in a cooling device is, is cooled. In this case, the cooling device a reservoir for storing the coolant, wherein the reservoir, for example, during or after deployment of the airbag is opened, leaving the coolant for cooling the gas used to inflate the gas bag in contact with get this gas. According to the invention is provided that the coolant has at least one cooling substance, a monohydric alcohol, a polyvalent alcohol, an ester, an ether, an alkane, an alkene, an alkyne and / or an alloyed one or unalloyed mineral, semi-synthetic or synthetic oil is. Mixtures of the aforementioned substances are also conceivable. Also, the aforementioned method involves the use of a subcombination the aforementioned substances as a cooling substance. Further is it is possible for the alkanes, alkenes and / or alkynes to pass through one or more oxygen, nitrogen and / or sulfur atoms may be substituted and / or interrupted.

In terms of Further variants or embodiments of the method is on the above explanations to variants and embodiments directed the airbag module, which claimed in an analogous manner to the Procedure apply.

The The invention also relates to the use of a monohydric alcohol, a polyhydric alcohol, an ester, an ether, an alkane, an alkene, an alkyne and / or an alloyed or unalloyed mineral, partly synthetic or synthetic oil and mixtures of the foregoing Substances as the cooling substance of a coolant for cooling one for inflating a gas bag in one Airbag module used for a motor vehicle gas. there It is possible that the alkanes, alkenes and alkynes pass through one or more oxygen, nitrogen and / or sulfur atoms may be substituted and / or interrupted.

In In one variant, the coolant is in a cooling device Contain a reservoir for storing the coolant includes, wherein the reservoir is adapted to open so that the coolant for cooling the for inflating the gas bag used gas in contact with this Gas can occur.

In terms of Further variants or embodiments of the use of the aforementioned Substances as a cooling substance is based on the above explanations referenced to variants and embodiments of the airbag module, the apply in an analogous manner to the claimed use.

Further Details of the invention are based on a shown in a figure Embodiment explained in more detail become. It shows:

1 a schematic sectional view through an airbag module.

The 1 shows a schematic sectional view of an airbag module 1 that has a gas bag 2 which is inflatable to protect a person, and a gas generator 3 that's for inflating the airbag 2 provides required gas. For this purpose, the gas generator 3 a detonator 3a on, which can be controlled via a vehicle-mounted control electronics. The gas bag 2 and the gas generator 3 of the airbag module 1 are on a generator carrier 4 fixed, together with one adjacent to the gas generator 3 arranged cooling device 5 which is used to cool the airbag to inflate 2 used gas serves.

The sectional plane of the in the 1 shown airbag module 1 runs - based on a built-in steering wheel state of the airbag module 1 - Parallel to a steering axis of the steering wheel (not shown).

The gas bag 2 has an inflow opening, through which into an interior I of the airbag 2 Gas from the gas generator 3 for inflating the airbag 2 can be initiated.

The cooling device 5 includes a reservoir 5a for storing a coolant K which is liquid in the operating temperature range of the airbag module (from approx. + 90 ° C to approx. -40 ° C) and which flows through an outflow opening 5b in the interior I of the airbag 2 can get. The coolant K has at least one cooling substance which is selected from the group comprising monohydric alcohols, polyhydric alcohols, esters, ethers, alkanes, alkenes, alkynes and alloyed or unalloyed mineral, semisynthetic or synthetic oils. When evaporating this Coolant creates a toxicologically harmless vapor, so that even with skin contact with this vapor or in an oral intake of steam or a corresponding aerosol no serious consequences for a vehicle occupants are to be feared.

The discharge opening 5b is designed nozzle-shaped, so that the coolant K, when it comes out of the reservoir 5a through the discharge opening 5b in an outflow direction R in the interior I of the airbag 2 is introduced, is atomized, that is, is fractionated into small droplets.

For squeezing the coolant K from the reservoir 5a the cooling device 5 For example, various methods known in the art may be used. It is always a closure V, which is the outflow 5b in the non-activated state of the airbag module closes, opened. This can be done, for example, by one in the reservoir 5a generated overpressure happen. It is also possible to use a reversibly openable or (re) closable valve as the closure V of the outflow opening 5b use.

Since at constant volume, the pressure in the gas bag 2 is located in the gas bag is proportional to the temperature of the gas is, by cooling a reduction in the gas bag 2 prevailing gas pressure achieved. That is, by means of the controllable cooling of the gas bag 2 located gas, the gas bag 2 adapted to a specific accident situation.

Of the Cooling effect occurs when the coolant K is atomized and hot, in the interior I gas is evaporated, the temperature of the gas is lowered because the conversion of the liquid phase of the Coolant in the gaseous phase, that is to provide required enthalpy of vaporization, energy must be applied.

in principle are the most diverse airbag designs conceivable in which a corresponding coolant K can be used.

1

airbag module

2

airbag

3

inflator

4

generator support

5

cooler

5a

reservoir

5b

outflow

I

inner space of the gas bag

K

coolant

R

outflow of the coolant

V

shutter

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102006010953 A1 [0002]
• - WO 2007/141335 A1 [0003]
• - DE 2236380 A1 [0004]
• - DE 2153639 A1 [0005]

Claims (13)

Airbag module for a motor vehicle, with - a gas bag ( 2 ) which is inflatable to protect an occupant with gas, - a gas generator ( 3 ) for generating the for inflating the airbag ( 2 ), and - an additional cooling device ( 5 ), which is a reservoir ( 5a ) for storing a coolant (K), wherein the reservoir ( 5a ) is adapted to be opened, so that the coolant (K) for cooling the airbag to inflate ( 2 ) can come into contact with this, characterized in that the coolant (K) comprises at least one cooling substance selected from the group comprising monohydric alcohols, polyhydric alcohols, esters, ethers, alkanes, alkenes, alkynes and alloyed or non-alloyed mineral, semi-synthetic or synthetic oils. Airbag module according to claim 1, characterized in that that the cooling substance has such properties, that inhalation of the cooling substance or the coolant (K) by a motor vehicle occupant toxicologically harmless is. Airbag module according to claim 1 or 2, characterized that the coolant (K) in addition to the cooling substance has at least one additive that is selected from the group comprising emulsifiers, surfactants, foam inhibitors, substances for Freezing point depression, substances to reduce or avoid a mist formation in an evaporation of the coolant (K) and biocides. Airbag module according to one of the preceding claims, characterized in that the coolant (K) additionally to the cooling substance comprises a gas in dissolved form. Airbag module according to claim 4, characterized in that that the gas is carbon dioxide. Airbag module according to one of the preceding claims, characterized in that the coolant (K) at room temperature essentially in liquid form, in particular as a solution, Emulsion or dispersion. Airbag module according to one of the preceding claims, characterized in that the freezing point of the coolant (K) at or below -40 ° C, in particular at or below -38 ° C, especially at or below -35 ° C and especially at or below -30 ° C. Airbag module according to one of the preceding claims, characterized in that the boiling point of the coolant (K) at or above + 90 ° C, especially at or above + 95 ° C, especially at or above + 100 ° C, especially at or above 105 ° C and especially at or above + 107 ° C. Airbag module according to one of the preceding claims, characterized in that the surface tension of the Coolant (K) at 20 ° C less than or equal to 150 mN / m, in particular less than or equal to 100 mN / m, in particular smaller or equal to 50 mN / m, and especially less than or equal to 25 mN / m is. Airbag module according to one of the preceding claims, characterized in that the surface tension of the Coolant (K) is lower than the surface tension pure water under the same conditions. Method for cooling a gas bag to inflate ( 2 ) in an airbag module ( 1 ) used for a motor vehicle by means of a coolant (K), which in a cooling device ( 5 ), the cooling device ( 5 ) a reservoir ( 5a ) for storing the coolant (K) and wherein the reservoir ( 5a ) is opened, so that the coolant (K) for cooling the airbag for inflating ( 2 ) used in contact with the latter, characterized in that the coolant (K) comprises at least one cooling substance selected from the group consisting of monohydric alcohols, polyhydric alcohols, esters, ethers, alkanes, alkenes, alkynes and alloyed or unalloyed mineral , semi-synthetic or synthetic oils. Use of a monohydric alcohol, a polyhydric alcohol, an ester, an ether, an alkane, an alkene, an alkyne, an alloyed or unalloyed mineral, semisynthetic or synthetic oil or mixtures of the aforementioned substances as the cooling substance of a coolant (K) for cooling a Inflating a gas bag ( 2 ) in an airbag module ( 1 ) used for a motor vehicle gas. Use according to claim 12, characterized in that the coolant (K) in a cooling device ( 5 ) containing a reservoir ( 5a ) for storing the coolant (K), wherein the reservoir ( 5a ) is adapted to be opened, so that the coolant (K) for cooling the airbag to inflate ( 2 ) used gas can come into contact with this.