EP2201242A1

EP2201242A1 - Ignition device especially for an internal combustion engine, and method for the production thereof

Info

Publication number: EP2201242A1
Application number: EP08787209A
Authority: EP
Inventors: Werner Herden; Martin Weinrotter; Pascal Woerner; Manfred Vogel; Juergen Raimann; Bernd Schmidtke; Heiko Ridderbusch
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2007-09-14
Filing date: 2008-08-14
Publication date: 2010-06-30
Also published as: US20100282195A1; WO2009037057A1; US8712197B2; DE102007044010A1

Abstract

The invention relates to an ignition device (27), in particular for an internal combustion engine of a motor vehicle, comprising a laser device (26) for generating laser pulses (24), and an optical fiber device (280) that is at least optically connected to the laser device (26) to apply pumping light (60) to the laser device (26). According to the invention, the optical fiber device (280) is designed and arranged in the region of the laser device (26) in such a way that radiation (70) which is incident in the region of the laser device (26) and/or in the region of a combustion chamber (14) associated with the laser device can be injected into the optical fiber device (280). The disclosed design and arrangement of the optical fiber device advantageously allow the radiation that is injected into the optical fiber device to be analyzed, in particular by a detector that is disposed at a distance, without having to provide additional, separate optical fiber devices for the radiation that is to be analyzed, because the radiation that is to be analyzed can be guided directly via the same optical fiber that is used for supplying the pumping light.

Description

description

title

Ignition device in particular for an internal combustion engine and manufacturing method thereof

State of the art

The invention relates to an ignition device, in particular for an internal combustion engine of a motor vehicle, with a laser device for generating laser pulses, and with an at least optically connected to the laser device optical fiber device for supplying the laser device with pump light.

The invention further relates to a manufacturing method for such an ignition device.

Disclosure of the invention

It is an object of the present invention to improve an ignition device and a manufacturing method thereof so that a simple production and a reliable and flexible operation of the ignition device are possible.

This object is achieved with the ignition device of the aforementioned type according to the invention in that the optical fiber device is designed and arranged in the region of the laser device that radiation occurring in the region of the laser device and / or in the region of the laser device associated combustion chamber in the optical fiber device can be coupled ,

The inventive design and arrangement of the optical fiber device advantageously allows the analysis of the injected into the optical fiber device radiation, in particular by a remotely located detector, without the need to provide additional, separate optical fiber means for the radiation to be analyzed, because the radiation to be analyzed can be conducted directly over the same optical fiber already used for the pumping light supply. This results in a particularly simple configuration and correspondingly low production costs.

In an embodiment of the invention, it is particularly advantageous for the laser device to be at least partially transmissive for wavelengths of the radiation, so that radiation to be analyzed is e.g. from the combustion chamber directly through the laser device can be coupled into the optical fiber device.

When using a light guide device with only a single optical fiber is also advantageously a particularly simple mechanical configuration.

The inventively also proposed use of a fiber optic device formed from a plurality of individual optical fibers advantageously allows a flexible arrangement of the optical fibers in particular in the laser device, so that a variety of different configurations is given solely due to the division and arrangement of the individual optical fibers in the laser device. In particular, in this case, at least a first part of the optical fibers forming the optical fiber device can also be used inter alia for transmitting the radiation of interest from the laser device to a remotely located evaluation unit. Another part of the optical fibers constituting the optical fiber means may be e.g. also exclusively for the transmission of pump light to the

Laser device can be provided and accordingly arranged in the laser device so that the most efficient irradiation of pump light is made possible in the laser device, while the coupling of other radiation from the area of the laser device in this further part is not or only partially possible.

The plurality of individual optical fibers preferably form a single strand, which may possibly be encased and - compared to a single fiber - has a correspondingly increased mechanical stability.

In a particularly advantageous embodiment of the ignition device according to the invention provided that at a remote from the laser device end of the optical fiber device is associated with a first number of optical fibers of the optical fiber device of an evaluation unit for evaluating the radiation. In this way, the radiation coupled into the relevant part of the optical fibers in the region of the laser device can be evaluated by the remotely located evaluation unit.

A particularly simple and efficient production of the ignition device according to the invention results according to the invention, when the first number of optical fibers, which is assigned to the evaluation, is arbitrarily selected, d. H. in particular, is not selected to belong to the first part, that is to say to those optical fibers which, in the region of the laser device, are e.g. are deliberately arranged so that the interested

Radiation in the optical fibers of this first part can be coupled. Erfmdungemäß has been recognized that even a statistical selection process of optical fibers from the optical fiber device usually ensures that sufficiently many of those individual optical fibers of the evaluation are assigned, in the other ends in the laser device and the radiation of interest is coupled. This configuration according to the invention advantageously eliminates the need to determine during the manufacture of the ignition device according to the invention special individual optical fibers from the optical waveguide device, into which the radiation of interest is also coupled. Rather, a certain proportion of the total existing optical fibers of the evaluation unit can be easily assigned according to the invention, wherein due to the statistical

Characteristics of the selection process ensures that always at least some optical fibers are selected, which can supply the radiation of interest from the range of the laser device of the evaluation unit. The non-selected optical fibers remain in this variant of the invention for supplying the laser device with pump light.

A further simplification of a manufacturing process of the ignition device according to the invention is advantageously given by the fact that at least one optical fiber has a different geometry from the geometry of the other optical fibers of the optical fiber device. In particular, the deviating geometry can have a cross-section or diameter deviating from the majority of the optical fibers, so that a correspondingly simple distinction can be made between optical fibers with normal geometry and optical fibers with inventively deviating geometry. Particularly preferably, for example, a single optical fiber of the inventive light guide device can be formed with a relatively large diameter, which can accordingly be used for example for transmitting the pump light from a pumping light source to the laser device, while further, a smaller diameter having optical fibers, for example, for the return of radiation of interest can be used from the range of the laser device to the evaluation unit.

Alternatively or additionally, it is also possible to use at least a portion of the optical fibers with a small cross-section or diameter in addition to the transmission of pump light. An inverse configuration is also conceivable, d. h., For example, it may be provided with a relatively large cross-section or diameter, a single optical fiber, which serves for the transmission of radiation of interest from the laser device to the evaluation unit, while further, provided with smaller diameter cross-section or optical fibers for the supply of pump light provide the laser device.

In a further very advantageous embodiment of the ignition device according to the invention, provision is made for the optical waveguide device to have a partial region of its overall length

Bending radius has, which is selected so that guided by the light guide device radiation in the subregion is at least partially decoupled from the light guide device. The decoupled radiation may on the one hand be supplied by a pumping light source pump light, but preferably in the region of the laser device coupled into the optical fiber device of interest radiation coupled to the invention bent portion of the optical fiber device to them for the purpose of analyzing a corresponding evaluation unit to feed.

It can also be provided particularly advantageously that the bending radius is selected such that the pumping light of a first wavelength can not be coupled out in the partial area such that radiation with wavelengths different from the first wavelength of the pumping light can be coupled out in the partial area. In this case, according to the invention, advantageously the wavelength dependency of the total reflection principle permitting the light pipe in the optical waveguide device or its individual optical fibers is utilized. Particularly advantageously, the wavelength of the pump light used is matched to the ignition device or the bending radius of the light guide device and the wavelengths of the radiation to be analyzed, that over a corresponding curvature of the optical waveguide device selectively only the radiation of interest is auskoppelbar while the pumping light is not already decoupled due to the curvature of the light guide device according to the invention and thus can be completely transferred to the laser device.

In a further very advantageous configuration of the ignition device according to the invention, provision is made for the optical waveguide device to have a plurality of partial regions with different bending radii, in each of which radiation of different wavelengths can be decoupled. As a result, as an optical filter circuit is realized, which can decouple via the definition of the corresponding bending radii hereby corresponding wavelength ranges of the guided in the light guide device radiation.

The corresponding bending radii are u.a. Depending on the number of individual optical fibers to be chosen accordingly so that at least for a certain part of the optical fibers, the total reflection of the wavelengths of interest is partially impaired in order to decouple the radiation can.

Particularly preferably, the optical waveguide device according to the invention in the sub-areas in which radiation is to be coupled, an opening in a surrounding jacket or even a region of the jacket, which is at least partially transparent for the radiation to be coupled out.

Moreover, it can advantageously be provided according to the invention that the optical waveguide device has an integrated evaluation unit, but at least an optoelectric transducer, so that the signal decoupled from the optical waveguide device or the corresponding radiation can be evaluated directly on site and converted into an electrical signal , The necessary for forwarding the electrical signal to an evaluation circuit or control unit or the like electrical connections such as cables according to the invention can be advantageously integrated into the

Optical fiber device, for example, by being enclosed together with the individual optical fibers by a common sheath.

According to the invention, as an alternative or in addition to the on-site provided opto-electrical Transducer also be provided a further optical fiber, which is substantially spatially separated from the remaining optical fibers. This further optical fiber can forward the radiation coupled out of the optical waveguide device according to the invention to a remote optoelectric converter or an evaluation unit and is likewise advantageously integrable into a jacket of the optical waveguide device. Due to its spatial separation from the remaining optical fibers of the optical fiber device, it can also be distinguished during production of the ignition device according to the invention in a simple manner from the remaining optical fibers and thus selectively connected to an evaluation, while the remaining optical fibers are optically connected, for example, with a pumping light source. This further, for analysis purposes usable optical fiber may alternatively or additionally be designed distinguishable by means of a different cross-section or the like of the remaining optical fibers.

In a further very advantageous embodiment of the ignition device according to the invention it is provided that at a remote from the laser device end of the optical fiber device, a pumping light source for generating the pumping light and a

Evaluation unit is provided for evaluating the radiation, wherein the pump light source spatially disposed between the end of the light guide device and the evaluation unit and is at least partially transparent to the radiation. According to the invention, it has been recognized that some pump light sources designed as semiconductor lasers are substantially transparent for wavelengths of interest of the radiation coupled into the light guide device in the region of the laser device. As a result, it is advantageously possible to use the entire optical waveguide device according to the invention for transmitting pump light to the laser device, and secondly to transmit the radiation coupled in at least part of the optical fibers of the optical waveguide in the region of the laser device to the pump light source in the return direction, through which and to supply them in this way to the pumping light source downstream evaluation unit.

Both the variant of the invention, which allows a curvature of the light guide device with the aim of Auskoppeins part of the radiation to be analyzed, as well as the further variant in which an evaluation of the pump light source is optically downstream advantageously allow the use of the entire cross section of the light guide device for transmitting the Pumplichts to the laser device and the radiation to be analyzed by the Laser device to an evaluation unit.

A particularly good adaptation of a cross section of the optical waveguide device to further optical elements is provided according to the invention in that an optical cross-section converter is provided at an end of the optical waveguide device remote from the laser device, which fixes the individual optical waveguides of the optical waveguide arrangement relative to each other in a predeterminable manner, in particular such that the individual optical fibers in the optical cross-section converter together form a cross section that deviates from the cross section of the optical fiber arrangement. In this way, it is possible according to the invention, for example, to transform a substantially circular cross-section of the optical waveguide into a substantially rectangular or linear cross-section, as is the case, for example, for frequently used semiconductor pump light sources which are formed by a line arrangement of several laser emitters next to one another.

Alternatively or in addition to the configuration described above, in which the radiation to be analyzed is transmitted through the pumping light source before it reaches the evaluation unit, a part of the optical fibers of the optical waveguide device which guides the radiation to be analyzed can also be transformed into a cross section by the optical cross-section converter , which is optimally adapted for the downstream evaluation unit.

The principle according to the invention can be used advantageously in ignition devices for internal combustion engines, in particular of motor vehicles, but can also be used very advantageously in conjunction with stationary engines, in particular large gas engines, or even turbines or the like.

As a further solution to the object of the present invention, a method for producing an ignition device according to claim 18 is given.

Further advantageous embodiments are the subject of the dependent claims.

Other features, applications and advantages of the invention will become apparent from the following description of embodiments of the invention, which are illustrated in the figures of the drawing. All features described or illustrated are self-explanatory or in any combination, the subject matter of the invention, regardless of their combination in the claims or their dependency and regardless of their formulation or representation in the description or in the drawing.

Short description of the drawing

In the drawing shows:

1 shows a schematic representation of an internal combustion engine with an ignition device according to the invention,

FIG. 2 shows an embodiment of the ignition device from FIG. 1 in detail,

3a-3d different configurations of the light guide device according to the invention in cross-section,

FIG. 3e schematically shows a bend defined twice according to the invention

Optical fiber device,

FIG. 4 shows a component of the ignition device according to the invention for defined bending of an optical waveguide device with integrated detector,

Figure 5 a

and FIG. 5b shows further embodiments of the ignition device according to the invention, and FIG

Figure 6 shows an embodiment of the ignition device according to the invention with an optical cross-section converter.

Embodiments of the invention

An internal combustion engine carries in Figure 1 in total the reference numeral 10. It is used to drive a motor vehicle, not shown, or to drive a generator. The Internal combustion engine 10 comprises a plurality of cylinders, of which only one is designated by the reference numeral 12 in FIG. A combustion chamber 14 of the cylinder 12 is limited by a piston 16. Fuel enters the combustion chamber 14 directly through an injector 18, which is connected to a designated also as a rail or common rail fuel pressure accumulator 20. External mixture formation is also possible

Injected into the combustion chamber 14 fuel 22 is ignited by means of a laser pulse 24 which is emitted by a laser device 26 comprehensive ignition 27 into the combustion chamber 14. For this purpose, the laser device 26 is fed via a light guide device 280 with a pumping light, which is provided by a pumping light source 30. The pump light source 30 is controlled by a control and regulating device 32, which also controls the injector 18.

For example, the pumping light source 30 may be a semiconductor laser diode that outputs a corresponding pumping light to the laser device 26 via the optical waveguide device 28 as a function of a control current. Although semiconductor laser diodes and other small-sized pump light sources are preferably used for use in the automotive field, any type of pump light source is principally usable for the operation of the ignition device 27 according to the invention.

FIG. 2 schematically shows a detailed view of the ignition device 27 from FIG. 1.

As can be seen from FIG. 2, the laser device 26 has a laser-active solid 44, to which a passive Q-switching 46, also referred to as Q-switch, is optically arranged downstream. The laser-active solid 44 forms here, together with the passive Q-switching circuit 46 and the coupling mirror 42 arranged on the left thereof in Figure 2 and the Auskoppelspiegel 48, a laser oscillator whose oscillatory behavior depends on the passive Q-switching 46 and thus at least indirectly controllable in a conventional manner is.

In the configuration of the laser device 26 shown in FIG. 2, the pumping light 60 is directed onto the coupling-in mirror 42 by the light guide device 280 already described with reference to FIG. Since the coupling mirror 42 is transparent to the wavelengths of the pumping light 60, this penetrates Pumplicht 60 in the laser-active solid 44 and leads to a known population inversion.

While the passive Q-switching circuit 46 has its basic state in which it has a relatively small transmission coefficient, laser operation in the laser-active solid 44 or in the solid 44, 46 confined by the input mirror 42 and the output mirror 48 is avoided. As the pumping time increases, however, the radiation density in the laser oscillator 42, 44, 46, 48 increases, so that the passive Q-switching circuit 46 fades, i. assumes a larger transmission coefficient and laser operation can begin.

This results in a laser pulse 24, also referred to as a giant pulse, which has a relatively high peak power. If appropriate, the laser pulse 24 is coupled into the combustion chamber 14 (FIG. 1) of the internal combustion engine 10 using a further optical waveguide device or directly through a combustion chamber window of the laser device 26, so that fuel 22 present therein is ignited.

According to the invention, the optical waveguide device 280 is designed and in the region of

Laser device 26 arranged that in the region of the laser device 26 and / or in the region of the laser device 26 associated combustion chamber 14 (Figure 1) occurring radiation in the optical fiber device 280 can be coupled, so that without providence separate optical fiber assemblies alone by means of the optical fiber device 280 to be analyzed radiation from the laser device to a remotely located evaluation unit is transferable.

FIG. 1 shows by way of example such an evaluation unit 100 which is arranged at an end 281a of the optical waveguide device 280 remote from the laser device 26 and in the present case in spatial proximity to the pump light source 30.

According to a first variant of the invention, the optical waveguide device 280 may have a single optical fiber for guiding the pumping light 60 (FIG. 2) and for guiding radiation to be analyzed, such as combustion chamber light and the like, thereby providing a particularly simple, compact and cost-effective configuration. However, the optical waveguide device 280 according to the invention is particularly preferably formed from a plurality of individual optical fibers combined in particular into a strand, of which at least a first part 280a, cf. 5a, it is arranged in the region of the laser device 26 that radiation 70 occurring in the region of the laser device 26 and / or in the region of the combustion chamber 14 associated with the laser device 26 can be coupled into this part 280a of the optical fibers.

By way of example, the radiation 70 may be pumping light 60 which has been supplied to the laser device 26 via the light guide device 280 and scattered in the laser device 26, or also to laser light 24, e.g. in a housing 26 'of the laser device 26 to components 49, 50 is scattered. Primarily, however, the radiation 70 to be analyzed preferably involves radiation which arises as a result of combustion processes taking place in the combustion chamber 14. FIG. 5a shows by way of example a dashed arrow 70 which represents radiation entering the housing 26 'of the laser device 26 from the combustion chamber 14 through the combustion chamber window 50. The radiation 70 may, for example, have a wavelength range in the range of visible light and of UV light.

As also shown in FIG. 5a, a portion 70 'of the light belonging to the laser pulse 24, for example scattered at the focusing optics 49, can also be coupled into the optical fiber 280a arranged according to the invention.

According to the invention, a coupling optics, which is not described in more detail in FIG. 5a, can be provided, which bundles the radiation of interest 70, 70 'into the optical fiber 280a.

In the configuration shown in FIG. 5a, only the optical fiber 280a forms the first part of the optical fibers in the sense of the present invention, while the second part 280b of the optical fibers forming the optical fiber device 280 alone serves to transmit pump light 60 to the laser device 26.

An alternative configuration of the ignition device 27 according to the invention is shown in FIG. 5b. In contrast to the configuration according to FIG. 5 a, the variant of the invention according to FIG. 5 b has an optical waveguide device 280 whose optical fibers all face one another Einkoppelspiegel 42 of the laser device 26 are arranged. In this configuration, the laser device 26 is advantageously at least partially transparent to the radiation 70 radiated into the housing 26 'from the combustion chamber 14, so that this radiation 70 is advantageously coupled into the optical waveguide device 280 through the laser device 26 and to a remotely located evaluation unit (not shown). can be supplied. In this case, the entire optically effective cross section of the optical waveguide device 280 can advantageously be used simultaneously for transmitting pumping light 60 (FIG. 5a) to the laser device 26 and for transmitting the radiation 70 from the laser device 26 to a remotely located evaluation unit. In contrast to this, in the configuration depicted in FIG. 5a, the optical cross section of the optical fiber 280a can not be used for efficient loading of the laser device 26 with pumping light 60.

According to the invention, it may advantageously be provided that a first part 280a (cf., FIG. 3a) of the plurality of optical fibers of the optical waveguide device 280 is used exclusively for transmitting radiation 70 coupled in the region of the laser device 26 to the evaluation unit 100 (FIG. The second part 280b comprising the remaining optical fibers of the optical waveguide device 280 can in this case be used to transmit pumped light 60 to the laser device 26.

Although the above-described configuration of the optical waveguide device 280 according to FIG. 3a advantageously permits dual use of the optical waveguide device 280 for simultaneous transmission of pumping light 60 and of radiation 70 to be analyzed. However, the configuration according to FIG. 3a requires a distinction of the individual optical fibers 280a, 280b during fabrication Ignition device 27 in order to selectively connect the optical fibers of the first part 280a with the evaluation unit 100 and the optical fibers of the second part 280b with the pumping light source 30.

The requirement to make such a distinction of individual optical fibers is avoided in another very advantageous variant of the invention, which is described below with reference to FIG. 3b. This variant of the invention provides that a certain number of the optical fibers of the optical waveguide device 280 are preferably assigned to the evaluation unit 100 likewise arranged there at an end 281a (see FIG. For example, the corresponding optical fibers can be mechanically separated from the remaining optical fibers of the optical fiber device 280 are separated and optically and mechanically connected to the evaluation unit 100.

According to the invention, however, it is advantageously provided that not specific individual optical fibers of the optical fiber device 280 are picked out in order to be optically or mechanically connected to the evaluation unit 100. Rather, according to the invention, an arbitrary choice is made among all the optical fibers of the optical waveguide device 280 in order to select those optical fibers which are connected to the evaluation unit 100. The statistical character of this selection method ensures that usually several such optical fibers are assigned to the evaluation unit 100, into which the radiation of interest 70 to be analyzed is actually coupled into the region of the laser device 26. Such optical fibers are shown hatched in FIG. 3b. The remaining individual optical fibers of the optical fiber device 280 not selected for connection to the evaluation unit 100 are accordingly not connected to the evaluation unit 100 (FIG. 1) and are available for the transmission of pumping light 60 from the pumping light source 30 to the laser device 26. In this variant of the invention in favor of a simplified manufacturing process, consciously accepted that by the statistical selection process, one or more such optical fibers are connected to the evaluation unit 100, in which no radiation to be analyzed 70 is coupled. Accordingly, these optical fibers do not contribute to the evaluation. Likewise, in this case also one or more such optical fibers can be connected to the pumping light source 30, which actually lead to radiation to be analyzed.

In a further very advantageous embodiment of the ignition device 27 according to the invention, it is provided that at least one optical fiber 280 1 has a geometry deviating from the geometry of the further optical fibers 280 2 of the optical fiber device 280. Such a configuration is shown in FIG. 3c. As can be seen from FIG. 3c, the at least one optical fiber 280 1 has a substantially larger diameter than the other optical fibers 280 2 of the optical fiber device 280, which are shown hatched in FIG. 3 c.

Such a different geometry allows during a manufacturing process of the ignition device 27 is a simple mechanical separation of at least one optical fiber 280 1 of the other optical fibers 280 2 and accordingly, for example, a Assignment of the at least one optical fiber 280 1 to the pumping light source 30, while the other optical fibers 280 2 are not connected to the pumping light source 30, but for example with the evaluation unit 100 (Figure 1).

An inverse configuration is also possible in which, for example, the optical fiber 280 1 is used to transmit radiation 70 from the laser device 26 to the evaluation unit 100, while the optical fibers 280 2 serve to transmit the pumping light 60 to the laser device 26.

In a further very advantageous embodiment of the ignition device 27 according to the invention, it is provided that the optical waveguide device 280 has a bending radius r in a partial region 282 of its overall length selected such that radiation 60, 70 guided by the optical waveguide device 280 is at least partially exposed in the partial region 282 the light guide device 280 can be coupled out.

A corresponding arrangement according to the invention for realizing the bending radius r can be seen from FIG. FIG. 4 shows, in a partial cross-section, a housing 100 'which has an optical detector 101 and thus has a housing to that shown in FIG

Evaluation device 100 offers comparable functionality. According to the invention, the evaluation unit 100 according to FIG. 4 moreover advantageously has a channel 102, through which the partial region 282 of the optical waveguide device 280 to be bent can be guided. As shown in FIG. 4, the channel 102 has a curved section which realizes the predetermined bending radius r. If the bending radius r is selected to be sufficiently small, the conditions for the total reflection of the radiation in the optical fibers required for guiding radiation in the optical waveguide device 280 are no longer completely fulfilled, so that at least some of the radiation guided in the optical waveguide device 280 is coupled out of the optical waveguide device 280, see. the arrow 71.

Accordingly, the detector 101 already described above is arranged in the region 282 of the bend of the optical waveguide device 280 in order to receive the radiation 71 coupled out of the optical waveguide device 280 according to the invention and to convert it into an electrical signal, for example. The evaluation unit shown in FIG. 4 advantageously has an example of a two-part housing, wherein the corresponding housing halves are preferably detachably connectable to each other, so that when the housing 100 'is open the optical fiber device 280 can be inserted into the channel 102. The subsequent closing of the housing 100' becomes the Optical fiber device 280 mechanically fixed in the evaluation unit 100, which ensures that the predetermined bending radius r is maintained and thus defined radiation 71 is coupled out of the optical fiber device 280.

The housing 100 'of the evaluation unit 100 according to FIG. 4 may, for example, also be molded onto a housing having the pumping light source 30 (FIG. 1). Furthermore, alternative configurations are conceivable in which separate means for realizing the bending radius r are provided which, in particular, are not integrated into the housing 100 'of the evaluation unit 100.

FIG. 3e shows a schematic diagram of a further configuration according to the invention, in which the optical waveguide device 280 is curved according to the invention at two regions 282a, 282b in order to decouple radiation 71a, 71b. Since the condition for total reflection in the

Optical waveguide 280 or the optical fibers contained in it is wavelength-dependent, can be specified by a suitable choice of the bending radius ra, rb, which wavelengths on the inventive curvature of the optical fiber device 280 are auskoppelbar from this. For example, a first radius of curvature ra in the region 282a may be selected such that only radiation 71a of a first wavelength range is coupled out of the optical waveguide device 280. The radius of curvature rb of the further region 282b is chosen differently, and accordingly radiation 71b of a different wavelength range is coupled out from the region 282b of the optical waveguide device 280.

It is particularly advantageous according to the invention that the bending radius r is chosen so that as far as possible no pumping light 60 is coupled out of the optical waveguide device 280 in order to enable an efficient pumping of the laser device 26. Rather, only a predeterminable proportion of the radiation 70, 71a, 71b to be analyzed should be coupled out of the optical waveguide device 280. For this purpose, the pumping light source 30, the laser device 26 and the corresponding bending radii r, ra, rb are to be matched accordingly. FIG. 6 shows a further very advantageous embodiment of the ignition device 27 according to the invention, in which, on the one hand, an evaluation unit according to FIG. 4 in the form of a dashed right-hand corner 100 is indicated. This evaluation unit 100 serves to decouple a first part 70a of radiation to be analyzed.

Moreover, the configuration according to FIG. 6 has a further evaluation unit 105, which is visually arranged downstream of a pump light source 30.

The configuration depicted in FIG. 6 furthermore has an optical cross-section converter 290, which transforms the essentially linear or rectangular beam cross section of the pumping light source 30 into a circular cross section of the optical waveguide device 280. This can be done, for example, in that the optical cross-section converter 290 the individual

Optical fibers of the light guide assembly 280 fixed in a predeterminable manner relative to each other, so that, for example, results in a configuration that is comparable to the beam cross section of the pumping light source 30. In the further course of the light guide device 280, the individual optical fibers are preferably combined into a single strand, which may optionally be surrounded by a protective sheath, for example a metal mesh or the like.

The laser device 26 from FIG. 6 is supplied with pumping light 60 via the pumping light source 30, the optical cross-sectional converter 290 and the optical waveguide device 280 in a manner known per se. In the region of the laser device 26 in the light guide device 280 or individual optical fibers thereof coupled radiation can be extracted in the form of the first part 70a by the evaluation device 100. A further part 70a 'of the radiation to be analyzed passes through the optical cross-section converter 290 and through the pump light source 30, and thus arrives at the further evaluation unit 105. This is advantageously made possible by a semiconductor laser forming the pump light source 30 being substantially transparent for the wavelengths of the part 70a 'of the radiation to be analyzed.

Although both evaluation units 100, 105 are depicted in the embodiment according to FIG. 6, it is self-evident that the provision already enables one of these two evaluation units to efficiently evaluate the radiation 70. In the case of those variants of the ignition device 27 according to the invention in which the coupling of radiation 70 out of the optical waveguide device 280 is made possible by controlled bending of the optical waveguide device 280, according to the invention it can furthermore advantageously be provided that an optoelectric transducer, an evaluation unit or the like directly FIG. 3d shows by way of example a partial cross section of such a light guide device 280. It can be seen from FIG. 3d that an optoelectric transducer 106 is arranged inside a jacket 283 of the light guide device 280 which is directly optically connected to at least one optical fiber the light guide device 280, in the present case preferably with the central optical fiber, which has a relatively large cross-section. The opto-electrical converter 106 is to be provided directly in the region of the planned bend of the optical waveguide device 280, wherein care must also be taken to ensure a correct angular position in order to enable efficient coupling of radiation into the transducer 106. Advantageously, an annular transducer can also be provided, which has, for example, radially spaced several photodetectors, etc., and at least partially surrounds the optical waveguide device 280, so that it is no longer necessary to maintain a correct angular position during the bending of the optical waveguide device 280.

According to the invention, electrical connecting lines for the opto-electrical converter 106 can advantageously also be integrated into the optical waveguide device 280 in such a way that they are guided, for example, parallel to the further optical fibers and through the common optical fibers

Sheath 283 are protected. Instead of an opto-electrical converter 106 may be provided according to the invention, a further optical fiber, which is arranged in the region to be bent such that due to the bending from the considered optical fiber emanating radiation coupled into the further optical fiber and is directed by this to a remote detector.

The inventive principle of coupling radiation out of the optical waveguide device 280 by means of a forced curvature or bending of the optical waveguide device 280 in the relevant region can advantageously also be used in the case of optical waveguide devices 280 which have a single optical fiber. Also, the return of radiation 70 from the laser device 26 to the opto-electrical converter or the evaluation unit 105 according to FIG. 6 can also be accomplished according to the invention by a light guide device 280 with a single optical fiber.

Claims

claims

1. ignition device (27), in particular for an internal combustion engine of a motor vehicle, with a laser device (26) for generating laser pulses (24), and with the laser device (26) at least optically connected optical fiber device (280) for supplying the laser device (26 ) with pumping light (60), characterized in that the optical waveguide device (280) is designed and arranged in the region of the laser device (26) that in the region of the laser device (26) and / or in the region of the laser device (26) Combustion chamber (14) occurring radiation (70) in the optical fiber device (280) can be coupled.

2. Ignition device (27) according to claim 1, characterized in that the

Laser device (26) is at least partially transmissive to wavelengths of the radiation (70).

3. Ignition device (27) according to any one of the preceding claims, characterized in that the light guide device (280) comprises a single optical fiber.

4. ignition device (27) according to one of claims 1 to 2, characterized in that the light guide device (280) comprises a plurality of optical fibers, and that at least a first

Part (280a) of the optical fibers in the region of the laser device (26) is arranged so that in the region of the laser device (26) and / or in the region of the combustion chamber (14) occurring radiation (70) in this part (280a) of the optical fibers can be coupled.

5. Ignition device (27) according to claim 4, characterized in that at one of the laser device (26) remote end (281a) of the optical fiber device (280) a first number of optical fibers of the optical fiber device (280) an evaluation unit (100) for evaluation associated with the radiation (70).

6. Ignition device (27) according to claim 5, characterized in that the first number of optical fibers is arbitrary, and in particular not selected to belong to the first part (280a).

7. ignition device (27) according to one of claims 4 to 6, characterized in that at least one optical fiber (280 1) one of the geometry of the other optical fibers (280 2) of the light guide device (280) deviating geometry, in particular a different cross section, preferably another diameter.

8. Ignition device (27) according to claim 7, characterized in that at least the

Optical fiber (280 1) is associated with the deviating geometry of an evaluation unit (100) or a pump light source (30).

9. ignition device (27) according to any one of the preceding claims, characterized in that the light guide device (280) in a partial region (282) of its total length has a bending radius (r), which is selected so that of the optical fiber device (280) guided radiation (60, 70) in the partial area (282) can be coupled out at least partially from the optical waveguide device (280).

10. Ignition device (27) according to claim 9, characterized in that the bending radius (r) is selected such that pumping light (60) of a first wavelength can not be decoupled in the subregion (282) that radiation (70) from the first Wavelength of the pump light (60) different wavelengths, however, in the subregion (282) can be coupled out.

11. Ignition device (27) according to any one of claims 9 to 10, characterized in that the light guide device (280) has a plurality of partial regions (282a, 282b) with different bending radii (ra, rb), in each of which radiation (70) of different wavelengths decoupled has.

12. Ignition device (27) according to any one of claims 9 to 11, characterized in that the light guide device (280) in the one or more sub-areas (282, 282 a, 282 b) an opening in a surrounding jacket (283) or a for the radiation (60, 70) to be coupled out has at least partially transparent region of the jacket (283).

13. Ignition device (27) according to one of claims 9 to 12, characterized in that the light guide device (280) in the one or more subregions (282, 282a, 282b) an integrated evaluation unit, but at least one opto-electrical converter, and / or a further optical fiber, which is spatially separated from the remaining optical fibers having.

14. Ignition device (27) according to spoke 13, characterized in that electrical connection means, in particular cables, in the light guide device (280) and / or in the jacket (283) are integrated.

15. Ignition device (27) according to one of the preceding claims, characterized in that at one of the laser device (26) remote end (281 a) of the

A pump light source (30) for generating the pump light (60) and an evaluation unit (100) for evaluating the radiation (70) is provided, wherein the pump light source (30) spatially between the end (281a) of the light guide device (280) and the evaluation unit (100) is arranged and at least partially transparent to the radiation (70).

16. An ignition device (27) according to any one of claims 4 to 15, characterized in that at one of the laser device (26) remote end (281a) of the optical fiber device (280) an optical cross-section converter (290) is provided which the individual optical fibers the optical fiber assembly (280) fixed in a predeterminable manner relative to each other, in particular such that the individual optical fibers in the optical cross-section converter (290) together form a cross-section which deviates from the cross section of the optical fiber assembly (280).

17. Internal combustion engine (10) with an ignition device (27) according to one of the preceding claims.

18. A method for producing an ignition device (27), in particular for a

Internal combustion engine of a motor vehicle, with a laser device (26) for generating laser pulses (24), and with an optical fiber device (280) at least optically connected to the laser device (26) for supplying the laser device (26) with pump light (60), characterized in that the optical waveguide device (280) is formed from a plurality of individual optical fibers, in particular in a strand, and in that at least a first part (280a) of the optical fibers is arranged in the region of the laser device (26) such that in the region of the laser device (26). and / or occurring in the region of one of the laser device (26) associated combustion chamber (14) radiation (70) in the first part (280a) of the optical fibers can be coupled.

19. The method according to claim 18, characterized in that at one of the laser device (26) remote end (281a) of the optical fiber device (280) a first number of optical fibers of the optical fiber device (280) an evaluation unit (100) for evaluating the radiation ( 70), wherein the first number of optical fibers are arbitrary, and in particular not selected to belong to the first part (280a).

20. The method according to any one of claims 18 to 19, characterized in that the light guide device (280) in a partial region (282) of its total length is bent in such a predetermined bending radius (r) that guided by the optical fiber device (280) radiation (60 , 70) in the partial region (282) can be coupled out of the optical waveguide device (280) at least partially.

21. The method according to claim 20, characterized in that in the subregion (282) an evaluation unit, but at least one opto-electrical converter, and / or another optical fiber, which is spatially separated from the remaining optical fibers, is integrated.

22. The method according to any one of claims 20 to 21, characterized in that electrical connection means, in particular cables, in the light guide device (280) and / or in the jacket (283) are integrated.