EP2710250A1

EP2710250A1 - Gas mixer, gas mixing system, gas engine

Info

Publication number: EP2710250A1
Application number: EP12724290.7A
Authority: EP
Inventors: Johannes PRINZ; Manolo ODERMATT; Anko Ernst
Original assignee: MTU Friedrichshafen GmbH
Current assignee: Rolls Royce Solutions GmbH
Priority date: 2011-05-19
Filing date: 2012-05-15
Publication date: 2014-03-26
Also published as: DE102011076106A1; CN103917767B; WO2012156077A1; DE102011076106B4; HK1199750A1; US8939129B2; US20140102422A1; CN103917767A

Abstract

Gas mixer (1, 100, 200) for mixing a first gas (G1) and a second gas (G2), in particular combustion air and a combustion gas, preferably for a gas engine, in particular a lean-burn gas engine, with a gas housing having: a Venturi tube (20), a flow body (40) for the first gas (G1), which flow body (40) is arranged in the Venturi tube (20) so as to form a mixing gap (60), an inflow tube (30), which is connected to the Venturi tube (20), to an inflow opening (70) to the Venturi tube (20) for the second gas (G2), an actuating element, by means of which the inflow cross section (71) of the inflow opening (70) can be variably adjusted, wherein the actuating element has a first actuating part and a second actuating part which restricts the inflow cross section (71), wherein the first actuating part is formed as a first gas housing part and the second actuating part is formed as a second gas housing part, wherein at least one of the gas housing parts (91, 92, 93, 94) forms a part of the Venturi tube (20) and/or of the inflow tube (30), and at least one of the gas housing parts (91, 92, 93, 94) can be moved with respect to another, wherein the movable gas housing part (93, 94) has a rotor of a linear motor (10, 10A, 10B).

Description

Gas mixer, gas mixing system, gas engine

The invention relates to a gas mixer according to the preamble of claim 1. The invention also relates to a gas mixing system and a gas engine.

A gas mixer of the type mentioned above is used for mixing a first gas and a second gas. In particular with regard to a gas engine, the first gas is in the form of combustion air, i. H. Fresh air or a lean air / gas mixture, and the second gas is formed in the form of a fuel gas. In the gas mixer, a suitable for the gas engine air / fuel gas mixture of combustion air and this mixed fuel gas is provided. In particular, for a lean-burn gas engine, it has proved to be important to set a lambda ratio, namely the ratio of a fuel gas to the combustion air, for example, to the power requirement of a lean gas engine. A gas mixer can be taken, for example, from EP 0 898 064 A1 in the form of a Venturi mixer, which is connected upstream of a lean-burn gas engine in a gas mixing system for mixing fuel gas to combustion air or a lean gas mixture.

In principle, it is possible to work with a Venturi mixer with different cross sections in order to increase the mixing quality of the air / fuel gas mixture; examples For example, EP 2 258 983 A2 describes a mixing section of a venturi mixer provided with different cross sections. In GB 154,920 an initially mentioned gas mixer is described with a moving Anströmkörper in a Venturi tube, whereby a mixing gap can be set differently.

From the brochure RMG980 gas mixer from 04/1998 of the company RMG a gas mixer is known, which has a solid Anströmkörper in a venturi a comparatively robust construction, as shown in prior art in Fig. 1. The inflow cross section for a second gas, in particular fuel gas, is formed there via a first and a second gas housing part delimiting the inflow cross section. A specified in the prospectus fixed inflow cross section between the solid gas housing parts determines the mixing ratio between the first gas (air or lean gas mixture in the Venturi tube) and a second gas (fuel gas in the inflow pipe).

It is desirable to have a variably adjustable inflow cross section. However, an inflow limiting limiting actuator that is suitably driven can be highly complex. Also, the drive of an actuator for the inflow limiting limiting actuators can be complicated. Angular gear and other propelled for transmitting power by means of gears mechanical drives are relatively susceptible to wear, so that in any case over the term an adjustment accuracy or setting speed suffers.

EP 2 016 994 A describes a gas mixer of the type mentioned in the introduction, in which a venturi tube has inlet openings for fuel gas in the region of a narrowed cross section, which can be changed during the mixing process by means of control elements. In this case, the regulating members comprise a regulating sleeve with fuel regulating openings which includes the narrowed cross section, wherein the size of passage cross sections for the fuel gas can be changed in the case of a mutual adjustment of the fuel regulating openings against inlet openings for the fuel gas. The narrowed cross-section is formed by means of a displacer arranged in the Venturi tube. Although this makes it possible to achieve a comparatively precise adjustment of a passage cross section; However, a corresponding control method is comparatively slow to perform, or the maximum permissible force is limited. In addition, the mechanical construction of the aforementioned control elements is relatively complex, so that the setting accuracy over the life of the gas mixer may suffer from wear and possibly pollution-related impairment. It is desirable to have a drive and an actuator that can be relatively easily implemented in a gas mixer and thereby allow a robust and fast and relatively accurate positioning of the actuator for establishing a Zuströmquerschnitts over a longer period. At this point, the invention begins, whose object is to provide a gas mixer, which is improved in terms of the prior art. In particular, the actuator should be designed comparatively robust. In particular, the actuator should be comparatively fast and yet accurately positionable. The object of the invention is also to specify a corresponding gas mixing system with the gas mixer and a suitable gas engine, in particular a lean-burn gas engine.

The object relating to the gas mixer is achieved by a gas mixer of the type mentioned, wherein according to the invention it is provided that the first actuating part is formed as a first gas housing part and the second actuating part as a second gas housing part, wherein at least one of the gas housing parts part of the Venturi tube and / or the inflow pipe forms, and at least one of the gas housing parts is movable against another, wherein the movable gas housing part comprises a rotor of a linear motor.

More specifically, it is provided that the first and / or second gas housing part is movable relative to the other and forms the moving part of a linear motor. For this purpose, suitable magnetic field generating means may be provided in or on the first and / or second gas housing part, for. Example, one or more permanent magnets, coils, etc., which are suitable for forming a rotor in interaction with a stator.

The invention is based on the consideration that a gas mixer of the type mentioned above already comparatively robust due to the use of gas housing parts for the actuator is designed to be able to operate over long periods without significant wear or contamination can. However, a drive for an actuator formed by a first and a second gas housing part delimiting the inflow cross-section still proves to be in need of improvement. The invention has recognized that for adjusting the inflow cross-section of at least one of the gas-housing parts should be movable against the other one. Further, the invention has recognized that the movement for a gas housing part should best take place in the direction of a longitudinal axis of the Venturi tube. In this respect, the invention has recognized that the concept of a Linear motion provides fundamental advantages over the concept of a rotary motion to drive the actuator or to the movement of the actuator. The invention therefore provides that the movable gas housing part has a rotor of a linear motor. The invention has recognized that a linear motor can comparatively easily be implemented for the relative movement of gas-housing parts when limiting an inflow cross-section.

In addition, the concept of the invention utilizes the advantages of a linear motor in order to set an inflow cross section exactly and therefore flexibly and highly dynamically. The invention has recognized that a linear motor can be implemented particularly well for this function. In this way, a flexible and fast, but nevertheless exactly positionable actuator is realized, which also comparatively high adjustment forces are available. Thus, a particularly robust and both fine and very dynamically adjustable gas mixer is realized.

Advantageous developments of the invention can be taken from the subclaims which specify in detail further preferred possibilities to further develop the concept of the invention with further advantages within the scope of the task.

Preferably, a diffuser space is delimited before an orifice of the inflow pipe by a dome on an inner side of the Venturi tube. The dome forms a further narrowing of the mixing gap wall of the Venturi tube. The inflow opening pointing to the inflow opening is advantageously arranged at the highest point of the dome.

Advantageously, in a first modification, the movable gas housing part is formed as a ring part, which delimits a ring dome along an inner circumference of the Venturi tube.

Advantageously, in a second modification, a one-sided movable gas-housing part is formed on a first side of the Venturi tube and a gas-housing part movable on another side is formed on a second side of the Venturi tube.

Preferably, the Anströmkörper has an elongated shape. In particular, the Anströmkörper extends with its longer axis along a longitudinal axis of the Venturi tube. Advantageously, a mixing gap is formed transversely to the longitudinal axis of the Venturi tube and transversely to the longer axis of the Anströmkörpers. This arrangement has changed with regard to the flow through the first gas proved to be particularly advantageous, at the same time good mixing of the first and second gas can be achieved.

In a first variant that further develops the concept of the invention, it may be provided that only the first gas housing part is movable relative to the second fixed gas housing part, in particular along the longitudinal axis, by means of the linear motor is displaceable. Conversely, analogously, only the second gas housing part can be displaceable against the first fixed gas housing part, in particular along the longitudinal axis, by the linear motor. Advantageously, the first gas housing part is a gas housing part initially flowed in the flow direction of the first gas. This can advantageously be ensured that the main flow resistance is carried by the fixed gas housing part.

In a particularly preferred development of the aforementioned first variant, it has proved to be advantageous that a longitudinal position of the inflow opening is fixed by means of the fixed gas housing part. The size of a mixing gap in the Venturi tube then advantageously determines itself essentially as the distance between the inflow cross section and the inflow body. In the aforementioned first variant, it is a gas mixer in which the inflow cross section is variable but the mixing gap itself has a fixed, free cross section. Advantageously, a comparatively fixed pressure loss can thus be set for the constriction at the mixing gap. As a result, the gas mixer can be operated comparatively stably with good mixing results, even with different inflow conditions of the second gas. As particularly preferred in the context of the first variant has been found that the longitudinal position in the region of a parallel to the longitudinal axis of the Anströmkörpers extending section is fixed. Preferably, the portion extending parallel to the longitudinal axis of the Anströmkörpers part of an approximately cylindrical portion of the Anströmkörpers. An admixture can be achieved with a comparatively low mixing resistance.

In a second likewise preferred further development variant, it has proven to be advantageous that both the first and the second gas housing parts are movable and the first and second gas housing parts are movable against the other. This has the advantage that the longitudinal position of a mixing gap is adjustably variable along the longitudinal axis of the delivery pipe. For this purpose, for example, both the first and the second gas housing parts can be moved "in the flow direction""backwards" along the longitudinal axis, or the mixing gap can also be moved to a rather forward position. be adjusted by both the first and the second gas housing part along the longitudinal axis "forward" are adjusted.

In the context of a particularly preferred development, the size of a mixing gap is essentially defined as the distance between the inflow cross section and the inflow body by means of a variable longitudinal position of the inflow opening to the venturi tube. In this way, in addition to a variable inflow cross section and the cross section of a mixing gap can be variably adjusted. This can be advantageous if a variable pressure loss is desired on the mixing section along the Anströmkörpers.

Has proved to be particularly advantageous that the longitudinal position is set in the region of a transverse to the longitudinal axis of the Anströmkörpers section. Depending on the absolute longitudinal position of the inflow cross section thus results in a different cross-section of the mixing gap. In particular, to a corresponding part of the Anströmkörpers is designed as an approximately pitifully rejuvenating part. As a result of the shape of the inflow body, which is thus already streamlined in itself and which prefers the mixture, the mixing gap is also increasingly increased when the inflow cross section moves "to the rear".

In the context of a particularly preferred constructional development of the gas mixer, the first and / or second gas housing part are part of a wall of the Venturi tube. The wall is to a particularly preferred manner in the form of a domed in the interior of the Venturi tube dome formed over an orifice of the inflow pipe. Between the mouth of the inflow pipe and inflow cross section in the dome, a suitable diffuser effect for the second gas is achieved.

In particular, it has proved to be advantageous for a solid gas housing part to form part of a wall of the venturi tube, which runs transversely to a longitudinal axis of the Venturi tube. Advantageously, the transverse to the longitudinal axis of the Venturi tube part of the wall is formed as a curved portion of the dome. For example, it has proven to be advantageous - both in the aforementioned first and second variants - that a solid gas housing part forms the inflow surface of the dome and a solid gas housing part forms the outflow surface of the dome. In the aforementioned first variant, preferably only a movable gas-housing part may be movable between the front fixed gas-housing part and the rear fixed gas-housing part. In the aforementioned second variant, two movable gas housing parts between the said front fixed gas housing part and the rear fixed gas housing part to be axially movable. The movement of the movable gas housing part is thus relatively little burdened by flow resistance, so it can be implemented with low friction and comparatively little effort from the linear motor. This is advantageous for a quick yet accurate positioning of the movable gas housing parts and thus advantageous for a quick and accurate adjustability of the inflow cross section.

In particular, a movable gas housing part can only form part of a wall of the Venturi tube, which extends parallel to a longitudinal axis of the Venturi tube. As a result, a flow resistance for a movable gas housing part is practically negligible.

In principle, the stator of the linear motor can be arranged on any position that is expediently available in the context of the constructional conditions opposite the rotor. It has proven particularly preferable for the stator of the linear motor to be arranged on a housing part which does not delimit the inflow cross section. As a result, the linear motor in the inflow area can be accommodated comparatively protected against soiling and the like. Particularly preferably, the stator of the linear motor can be formed on the inflow pipe. The linear motor can be accommodated thereby comparatively space-saving. Each movable gas housing part preferably has a rotor of a linear motor.

Embodiments of the invention will now be described below with reference to the drawing. This is not necessarily to scale the embodiments, but the drawing, where appropriate for explanation, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing reference is made to the relevant prior art. It should be noted that various modifications and changes may be made in the form and detail of an embodiment without departing from the general idea of the invention. The disclosed in the description, in the drawing and in the claims features of the invention may be essential both individually and in any combination for the development of the invention. In addition, all combinations of at least two of the in the description, the drawing and / or the claims fall within the scope of the invention. disclosed features. The general idea of the invention is not limited to the exact form or detail of the preferred embodiment shown and described below or limited to an article that would be limited in comparison with the subject matter claimed in the claims. For the given design ranges, values within the stated limits should also be disclosed as limit values and be arbitrarily usable and claimable. For simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar function.

Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing; this shows in:

1 shows a gas mixer, as it is known from the state of the art from the brochure RMG980 RMG;

Fig. 2 is a sectional structural view of a gas mixer according to a first preferred embodiment;

Fig. 3 is a sectional structural view of a gas mixer according to a second preferred embodiment.

Fig. 1 shows in section a principle known from the prior art possibility for the execution of a gas mixer 1. The gas mixer 1 is formed by an approximately T-shaped converging Venturi tube 2 and 3 inlet pipe in the Venturi tube 2 is a Anströmkörper 4 fixed , The wall of the Venturi tube 2 is also everted along an inner circumference by a dome 5 above the mouth 3.1 of the inflow pipe 3. Between the dome 5 and the Anströmkörper 4 so a symmetrical to the longitudinal axis A of the Venturi tube 2 lying annular mixing gap 6 is formed. At its approximately smallest dimension, the dome 5 an inflow opening 7, which allows the ringing as the inflow of gas from the inflow pipe 3. An opening 8 in the Venturi tube can be used for pressure measurement.

The gas mixer 1 designed in this way according to the Venturi principle can be connected with the Venturi tube 2 to a gas line for a first gas G1, which is inevitably accelerated in the region of the mixing gap 6 when flowing through the gas mixer 1, and so on a static pressure in the region of the mixing gap is lowered relative to the pressure conditions in the inflow pipe 3. Thus, a second gas G2 is sucked out of the inflow pipe 3 firstly into the diffuser space defined by the dome 5 and then through the inflow opening 7 into the venturi pipe 2. The second gas G2 mixes in the region of the outflow side of Anströmkörpers 4 with the first gas G1. The mixing ratio between the first gas G1 and the second gas G2 basically follows exponential -ggfs according to the Venturi principle. linearly approximated characteristic, which is essentially determined by the inflow section 7.1 of the inflow opening 7. Should the inflow opening be comparatively precise and as flexible as possible with comparatively high dynamics.

Incidentally, the Anströmkörper 4 may be designed depending on the conditions of the flow, on the one hand to achieve the best possible mixed mixture of the gas G1 and G2 and on the other with as quickly as possible again adjusting homogeneous flow conditions. Nevertheless, in the prior art, the mixing ratio between the first and second gas G1, G2 is adjusted by suitable flow rate valves.

The concept of the invention has recognized that, depending on the design, an inflow opening 70 should be adjustable comparatively exactly and as flexibly as possible with comparatively high dynamics. The concept achieves this with a linear motor 10, 10a, 10b as will be explained below.

FIG. 2 shows, by way of example, a first gas mixer 100, based essentially on the concept of the first further developing variant.

The gas mixer 100 has an approximately T-shaped converging Venturi tube 20 and an inflow pipe 30. The Venturi tube 20 extends along a longitudinal axis A and has a fixed Anströmkörper 40 which is arranged symmetrically to the longitudinal axis A and with its elongate axis collinear to the longitudinal axis A. The wall of the Venturi tube 20 forms a dome 50, which bulges in the interior of the Venturi tube 20. Between the dome 50 and the Anströmkörper 40 so that a mixing gap 60 is formed, which extends annularly around the Anströmkörper 40 between the outer surface of the Anströmkörpers 40 and the outer surface of the dome 50; this at the location of the smallest distance between dome 50 and Anströmkörper 40. In the dome 50, an opening 80 is also formed. This serves primarily for attachment of Anströmkörpers 40. As an opening, however, this can also serve as a pressure equalization or for attaching a probe or the like.

About the mouth 31 of the inflow pipe 30 so an annular around the Anströmkörper 40 running around diffuser space 51 is formed, which is bounded by the dome 50. An inflow opening 70 in the dome 50 has an inflow cross section 71, which in the present case is variably adjustable, while a cross section 61 of the mixing gap 60 is fixed in the first embodiment shown in FIG. The dimensions of the cross sections 61, 71 are basically dependent on the size of a gas mixer 100, 200. Concretely, in the present case, the cross section 61 is to be formed with a measure of, for example, about 40 mm, while the inflow cross section 71 is variably adjustable in the range of a dimension between, for example, 0 and 15 mm , These dimensions have proven to be particularly preferred for a Anströmkörper 40 with a diameter ratio of the largest to smallest diameter D / d of about 120mm / 80 mm.

In this way, with the gas mixer 100 shown in Fig. 2, a first gas G1 -here in the form of fresh air and a second gas G2 -here in the form of a fuel gas such as natural gas, biogas or other methane-containing gas in a particularly advantageous manner an air gas mixture G1 + G2 according to the illustrated with reference to FIG. 1 Venturi riprinzip.

In the present case, the inflow cross section 71 of the inflow opening 70 can be adjusted by a movable second gas housing part 93, which is movable back and forth between a first fixed gas housing part 91 and a second fixed gas housing part 92 in order to adjust the inflow cross section 71 of the inflow opening 70 as required. In the present case, the first fixed gas-housing part 91 is formed as an upstream-side arched part of the dome 50. The second fixed gas-housing part 92 is formed as a downstream-side curved part of the dome 50. The movable gas housing part 93 has an exclusively parallel to the longitudinal axis A extending outside, which can be flush with the initially adjacent outer sides of the first and second fixed gas housing part 91, 92. The movable gas-housing part 93 is thus hardly hindered in its movement by a pressure or similar flow resistance of the flow of the first gas G1 or the gas mixture G1 + G2 in the Venturi tube 20. The movable gas housing part 93 can thus be moved relatively free of resistance-that is, practically free. In the present case, an actuator 90 is thus formed by means of which the inflow cross section 71 of the inflow opening 70 is variably adjustable, wherein the actuator 90 is formed by the first fixed gas housing part 91 and the movable gas housing part 93. Both gas housing parts 91, 93 form part of the wall of the Venturi tube 20, specifically in the present case a part of the wall of the dome 50. In the present case, the movable gas housing part 93 is driven by a drive in the form of a linear motor 10. Concretely, a rotor 11 of the linear motor 10 is formed on the movable gas housing part 93, while the stator 12 of the linear motor is fastened to the material or in the wall of the inflow pipe 30 (on the one hand) or the venturi pipe 20 (on the other hand). When energized linear motor 10 - according to a Positionsvorgabe- the movable gas housing part 93 thus between the first and second fixed gas housing part 91, 92 exclusively in the direction of the longitudinal axis A back and forth to be movable. The axis a of the or of the rest of the cylinder-like circumference of the gas housing 93 multiply arranged rotor 11 of the linear motors or 10 thus runs parallel to the longitudinal axis A of the Venturi tube 20. Of course, the sectional view of Fig. 2 shows only a section through a total annular arrangement of a plurality of linear motors 10 or a single annular linear motor 10 having a plurality of elements to form a rotor 11 or a starter 12. Such measures can be taken in various forms to represent a suitable linear motor system of a single or multiple linear motors 10, without to deviate from the generally claimed concept of the invention according to the claims.

For structural implementation, the movable glass housing part 93 has an approximately Z-shaped cross-section in sectional view - an otherwise annular shape. In this case, a first leg 93.1 of the Z-shaped cross section (or a first annular course with a smaller cross section) forms part of the wall of the dome 50. A second leg 93.2 of the Z-like cross section (or a second annular course with a larger cross section) is a carrier of the rotor 11 of the linear motor 10. The two cross-sectional parts 93.1, 93.2 (ring part of smaller diameter and ring part larger diameter) are integrally connected to one piece about a standing approximately perpendicular to the longitudinal axis a part 93.3. Both legs 93.1, 93.2 of the Z-shaped cross-section are aligned along the axis a as well as the longitudinal axis A of the Venturi tube. In order to enable a displacement of the movable gas-housing part 93, the diffuser space 51 enclosed by the dome 50 is extended correspondingly via a rear fixed gas-housing part 92 of the dome 50. A movement of the movable gas housing part 93 takes place in the diffuser space 51 and increases it with enlargement of the inflow section 71 and reduces this with a reduction of the inflow 71.

The presently described first embodiment is particularly suitable for additional adjustment of the mixing ratio of the first gas G1 to the second gas G2 via the inflow cross section 71.

Moreover, the first embodiment shown in FIG. 2 has an advantageously formed contour of the flow body 40. This has along the longitudinal axis A at the longitudinal position of the inflow opening 70 an approximately cylindrical part 41 with an outer surface 42 running parallel to the longitudinal axis A. This first guarantees that a constant cross section 61 of the mixing gap 60 remains over the entire variance of the inflow cross section 71. Only beyond an adjustment amplitude of the movable gas housing part 93, the Anströmkörper 40 has an approximately conically tapered portion 43 with transverse to the longitudinal axis A extending surface 44. FIG. 3 shows a gas mixer 200 which substantially follows the concept of the second variant. This also has an actuator 90 'designed according to the concept of the invention with partial actuators 90a, 90b, which is explained below in contrast to the variant in the gas mixer 100 of FIG. 2. For the remainder of identical or similar parts or parts of identical or similar function, the same reference numerals are used as in FIG. 2 and reference is made in this regard to the description of FIG. 2.

Also in the present case, an actuator 90 'with gas housing parts of a wall of a dome 50 is formed. In the present case, however, the actuator 90 'is formed exclusively with movable gas housing parts, namely a first movable gas housing part 93 and a second movable gas housing part 94. Both movable gas housing parts 93, 94 have an approximately Z-shaped cross-section of a ring shape, as with reference to FIG has been described. The ring parts with a smaller diameter of the variably adjustable inlet opening 70 are facing. The ring parts with a larger cross section each carry a stator 11a, 11b of a linear motor 10a, 10b. The ring part with a smaller cross section is designated 93.1 or 94.1. The ring part of larger cross section is designated 93.2 or 94.2. The two ring parts connecting substantially perpendicular to the longitudinal axis A extending ring portion is denoted by 93.3 or 94.3.

The two movable gas-housing parts 93, 94 are both movable between a first fixed gas-housing part and a second fixed gas-housing part 91, 92. As a result, the inflow cross section 71 of the inflow opening 70 between the ring sections 93.1 and 94.1 is variably adjustable. The ring sections 93.2, 94.2 extend for this purpose in a groove formed essentially by the fixed gas housing parts 91, 92 in the diffuser space 51, which serves as a guide element; that is, as a guide element for the carrier of the rotor 11a, 11b of a first and second linear motor 10a, 10b. A part of the guide groove surface is formed by the stator 12a, 12b of the linear motor 10a, 10b. Similar to the embodiment explained with reference to FIG. 2, the diffuser space 51 is therefore extended to form a guide groove with the first and second fixed gas housing parts 91, 92. The guide groove 51a serves to guide the ring portion 93.2 larger cross section. The guide groove 51b serves to guide the ring section 94.2 of larger cross-section.

In principle, the linear motors 10a, 10b are constantly energized. The inflow cross section 71 can be variably adjusted in different ways. On the one hand, the linear motor 10b can remain unactuated and the linear motor 10a can be actuated, i. H. energized and acted upon with a position specification. In this way, the movable gas-housing part 94 remains at the same position while the other movable gas-housing part 93 is moved relative to the gas-housing part 94 according to a preset position and enlarges or reduces the inflow section 71.

The reverse procedure with interchanging the rollers for linear motor 10a and 10b-d. H. Operation of linear motor 10b with stationary linear motor 10a is also possible.

Above all, in contrast to the first embodiment of FIG. 2, the gas mixer 200 of FIG. 3 offers the possibility not only of adjusting the inflow cross section 71, but also of setting the cross section 61 of the mixing gap 60 variably. Basically thereby a pressure loss on the mixing section is variably adjustable and thus the suction effect on the second gas G2 in the inflow pipe 30. In the present case this is achieved in that the inflow opening 70 is arranged at a longitudinal position of the longitudinal axis A, in the region of a transverse to the longitudinal axis of the Anströmkörpers 40 dur- fenden section 43 is located. The Anströmkörper 40 here has a transverse to the longitudinal axis surface 44 to form an approximately conically tapered portion 43. A cylindrical part -the part 41 with surface 42 in the gas mixer 100- is missing here. At the conically tapering part 43 directly adjoins the upstream part 45.

As a result, the actuator 90 'of the gas mixer 200 is formed with a first movable gas housing portion 93 and a second movable gas housing portion 94, both gas housing portions 93, 94 defining the inflow section 71 and being part of the wall of the mandrel 50 at the same time. The movable gas-housing parts 93, 94 can each be driven individually via their own linear motors 10a, 10b, that is, they can be moved separately or both simultaneously according to a corresponding position specification. With simultaneous movement of the gas housing parts 93, 94, the inflow opening 70 can be positioned along a longitudinal axis to a desired longitudinal position. A subsequent relative movement-if it is effected by both linear motors 10a, 10b or only one of them-can then adjust the inflow cross-section 71.

LIST OF REFERENCE NUMBERS

1, 100, 200 gas mixer

10, 10a, 10b linear motor

11, 11a, 11b runner

12, 12a, 12b stator

2, 20 Venturi tube

3, 30 inflow pipe

31 estuary

4, 40 flow bodies

42 outer surface

43 rejuvenating part

45 upstream part

5, 50 Dom

51 diffuser room

6, 60 mixing gap

61 Cross section

7, 70 inflow opening

7.1, 71 inflow cross section

8, 80 opening for attachment of Anströmkörpers 4, 40th

G1 first gas

G2 second gas

G1 + G2 air-gas mixture

90,90 ', 90a, 90b actuator

91, 92, 93 Gas housing part 93.1, 93.2, 93.3, 94.1, 94.2 leg, ring part, ring section A, a longitudinal axis

Claims

claims

A gas mixer (1, 100, 200) for mixing a first gas (G1) and a second gas (G2), in particular a combustion air and a fuel gas, preferably for a gas engine, in particular a lean-burn gas engine, having a gas housing:

a Venturi tube (20)

a flow body (40) for the first gas (G1) arranged in the venturi tube (20) to form a mixing gap (60),

an inflow pipe (30) connected to the venturi tube (20) to an inflow opening (70) to the venturi tube (20) for the second gas (G2),

an actuator by means of which the inflow cross section (71) of the inflow opening (70) is variably adjustable, wherein the actuator has a first and a second, the inflow cross section (71) limiting actuator

characterized in that

the first actuating part is formed as a first gas housing part and the second actuating part as a second gas housing part, wherein at least one of the gas housing parts (91, 92, 93, 94) forms part of the Venturi tube (20) and / or the inflow pipe (30), and

at least one of the gas housing parts (91, 92, 93, 94) is movable against another, wherein

the movable gas housing part (93, 94) has a rotor of a linear motor (10, 10A, 10B).

2. Gas mixer according to claim 1, characterized in that

the inflow body (40) extends along a longitudinal axis (A) of the venturi tube (20) and a mixing gap (60) is formed transversely to the longitudinal axis.

3. Gas mixer according to claim 1 or 2, characterized in that

only the first gas housing part (93) is movable against the second fixed gas housing part (91) or only the second gas housing part is movable against the first fixed gas housing part.

Gas mixer according to one of claims 1 to 3, characterized in that by means of the fixed gas housing part (91) defines a longitudinal position of the inflow opening (70) and the size of a mixing gap (60) substantially as a distance between the inflow cross section (71) and the Anströmkörper (40 ).

Gas mixer according to one of claims 1 to 4, characterized in that the longitudinal position in the region of a parallel to the longitudinal axis (A) of the Anströmkörpers (40) extending portion of an approximately cylindrical portion of the Anströmkörpers (40) is fixed.

Gas mixer according to one of claims 1 or 2, 5, characterized in that both the first and the second gas housing part (93, 94) is movable and the first and second gas housing part is movable against the other.

Gas mixer according to one of claims 1, 2 or 5, 6, characterized in that

by means of a variable longitudinal position of the inflow opening (70) to Venturi tube (20), the size of a mixing gap (60) is set substantially as a distance between the inflow cross section (71) and the Anströmkörper (40)

Gas mixer according to one of claims 1, 2 or 6, 7, characterized in that

the longitudinal position in the region of a transverse to the longitudinal axis of the Anströmkörpers (40) extending portion of an approximately conically tapered portion of the Anströmkörpers (40) is fixed.

Gas mixer according to one of claims 1 to 8, characterized in that the first and / or second gas housing part (91, 92, 93, 94) form part of a wall of the Venturi tube, wherein the wall of a domed into the interior of the Venturi tube dome (50) forms over an opening of the inflow pipe.

Gas mixer according to one of claims 1 to 9, characterized in that a movable gas housing part (93, 94) only a part of a wall of the Ventu- Rirhren forms, which extends parallel to a longitudinal axis (A) of the Venturi tube (20).

11. Gas mixer according to one of claims 1 to 10, characterized in that a fixed gas housing part (91, 92) forms part of a wall of the Venturi tube (20) which extends transversely to a longitudinal axis (A) of the Venturi tube.

12. Gas mixer according to one of claims 1 to 11, characterized in that the stator (12, 12a, 12b) of the linear motor (10, 10a, 10b) is arranged on a the inflow cross section (71) not limiting gas housing part.

13. Gas mixer according to one of claims 1 to 12, characterized in that the stator (12, 12 a, 12 b) of the linear motor at the inflow pipe (30) is formed.

14. Gas mixer according to one of claims 1 to 12, characterized in that each movable gas housing part (93, 94) has a rotor (11, 11a, 11b) of a linear motor (10, 10a, 10b).

15. Gas mixing system or gas engine, in particular lean-burn gas engine, with a gas mixer according to one of claims 1 to 14.