JP2006514254A - Nozzle for spraying liquid fuel - Google Patents

Abstract

The present invention includes a nozzle (20) having an air inflow range (50), an air outflow range (52), and a flow path (54) connecting the air inflow range (50) and the air outflow range (52). The present invention relates to a nozzle for spraying liquid fuel by flowing air. The nozzle (20) is made of a ceramic material, air guide means (56) for swirling the incoming air is provided in the air inflow range (50), and the air guide means (56) is formed integrally with the nozzle (20). ing. The invention further relates to a heating device (10) for mobile use comprising such a nozzle (20).

Description

  The present invention relates to a nozzle for spraying liquid fuel with air flowing through a nozzle, having an air inflow range, an air outflow range, and a flow path connecting the air inflow range and the air outflow range.

  This type of nozzle is used, for example, in a vehicle heating device. Such a vehicle heating apparatus can be operated as an auxiliary heater and / or a parking heater, for example.

  The nozzle is used to supply combustion air. In this case, based on the flow of combustion air, a liquid fuel, for example diesel fuel or gasoline, is guided and sprayed together from the fuel needle. Thereby, an air-fuel mixture composed of combustion air and fuel is obtained. In some cases, this air-fuel mixture can be combusted after being mixed with air supplied from another flow path. Thereby, heat necessary for heating operation is generated. The heat generated by the burner warms the heat medium, such as water or air.

  Many state-of-the-art nozzles are made of metal. In this case, casting parts or turning parts are used. Such elements have the disadvantages of relatively high fabrication costs and generally high metal thermal conductivity. This thermal conductivity is a problem when the temperature in the range of the fuel needle rises excessively based on the heat generated by the burner. In order to solve this problem associated with metal nozzles, it has already been proposed in previous patent applications to use ceramic nozzles.

  In order for the combustion air and fuel to be mixed by the nozzle in their common path, the flow state of the combustion air is important. In order to improve the flow state of the combustion air, Patent Document 1 has already proposed that the combustion air is swirled. This greatly improves the spray quality and thus the efficiency of the burner. This is because the combustion air velocity increases based on the applied tangential motion component. In order to impart such a swirl motion, a support body having swirl vanes is provided in front of the inlet range of the nozzle. Such a support with swirl vanes arranged in the foreground has the disadvantage of requiring additional parts. Based on this additional component, tolerances for the smooth functioning of the nozzle can sometimes be exceeded.

In the case of state-of-the-art heating systems, it is also problematic to maintain a narrow tolerance for the positioning of the glow plug with respect to the incoming fuel / air mixture.
German Patent Application Publication No. 10039152

  The problem underlying the present invention is a nozzle that can be produced at low cost, has a low thermal conductivity compared to metal, produces advantageous properties regarding the flow state of the combustion air, and avoids adjustment problems. Is to provide.

  This object is achieved according to the invention by the features of claim 1.

  Advantageous embodiments of the invention are described in the dependent claims.

  In the present invention, in the nozzle described at the beginning, the nozzle is made of a ceramic material, air guide means for swirling inflowing air is provided in the air inflow range, and the air guide means is formed integrally with the nozzle. Thereby, the nozzle which can be manufactured at low cost is provided. Ceramic materials can be easily processed. In this case, many deformations are possible with respect to molding. In particular, the air guiding means for swirling the combustion air outside the air inflow range can be formed integrally with the nozzle. Based on the use of ceramics, there is another advantage that the fuel flowing out of the nozzle will not ignite because the temperature in the range of the nozzle around the fuel needle disposed in the nozzle will not be too high. The tolerance can be easily maintained by the integral formation of the air guiding means. This is because an incorrect adjustment of the air guiding means during the assembly of the burner is no longer possible.

  According to the invention, it is advantageous if the nozzle is provided with means for holding the glow plug. The positioning of the glow plug relative to the nozzle is an important parameter for the starting condition of the burner. In the case of a state-of-the-art heating device, the glow plug is generally held by a burner casing, so that positioning variations with respect to the nozzle occur. Due to the feature of the nozzle according to the invention that the nozzle itself comprises means for holding the glow plug, such an error does not occur. The glow plug is always in the same position relative to the nozzle.

  In the nozzle according to the invention it is furthermore advantageous if at least part of the nozzle has a substantially cylindrical shape and the air guiding means form a radially offset passage. The air that flows in perpendicular to the axis of the nozzle is not supplied in the radial direction, but is supplied in a shifted manner with respect to the radial direction. This deviation determines the swirl motion imparted to the combustion air, and thus the flow conditions and ultimately the characteristics and quality of the combustion.

  It is particularly advantageous if the air guiding means has a substantially triangular bottom and rounded corners. Thereby, the shift of the passage can be easily realized. Rounding the corners is advantageous for uniform flow conditions.

  Furthermore, it is advantageous if the air guiding means are formed as vanes. Such vanes also provide a staggered passage, which can also positively affect the quality of combustion.

  In another advantageous embodiment of the invention, the means for holding the glow plug is formed as a hole extending obliquely with respect to the cylinder axis. The glow plug need only be inserted into the hole for proper positioning. The stopper on the glow plug and / or the stopper in the hole guides the glow plug to an optimum position with respect to the nozzle.

  In the nozzle according to the present invention, at least a substantially cylindrical portion of the nozzle is provided with a substantially cylindrical protruding portion having an enlarged diameter, and the means for holding the glow plug extends obliquely with respect to the cylindrical axis, and the protruding portion is It is very advantageous if it is formed as a through-hole. As a result, the glow plug is held within a range that does not affect the flow state of the inflowing fuel / air mixture as much as possible. This can be easily realized by a cylindrical protrusion having a larger diameter than the nozzle body.

  Similarly, it is very advantageous if at least the substantially cylindrical part of the nozzle is provided with an enlarged substantially cylindrical projection, the cylindrical projection being provided with a notch for receiving the assembly bolt. . This assembly bolt can be fixed to the heat shield of the burner, for example. Thereby, the relative positioning of the nozzle is determined by the notch of the protrusion and the position of the assembly bolt. Therefore, the assembly is very simple and possible with small errors.

  It is very advantageous if the nozzle is a venturi type nozzle. Thereby, the venturi effect for spraying the fuel flowing out from the fuel needle can be advantageously combined with the swirl motion imparted to the combustion air. Thus, the venturi effect assists combustion and results in high quality combustion.

  The basis of the present invention is the recognition that the use of ceramic materials provides a nozzle that can be reshaped within a wide range and can be manufactured at low cost. Therefore, the nozzle can be formed so that air guide means for swirling the inflowing combustion air can be formed integrally with the nozzle. Ceramics have the further advantage of avoiding undesirably high temperatures within the fuel needle.

  Another problem is to provide a heating device for mobile applications that can be manufactured at low cost.

  This problem is solved by the features of claim 10. The advantages indicated in connection with the nozzle according to the invention also arise with the heating device according to the invention.

  The present invention will now be described by way of example based on preferred embodiments with reference to the accompanying drawings.

  In the following description of the figures, the same reference signs refer to the same or similar elements.

  FIG. 1 is a schematic partial sectional view of a heating apparatus to which the present invention is applicable. A heating device 10 with a burner 12 for burning a fuel / air mixture is shown. The heating device 10 includes an annular passage type fan 14 having a fan motor 36. The combustion air 42 is sucked from the air inflow pipe 16 by the annular passage type fan 14 and blown out into the combustion air collecting chamber 18 on the discharge side. The combustion air in the combustion air collecting chamber 18 is divided into primary air and secondary air. The primary air is conveyed into the combustion chamber 24 through the nozzle 20. The nozzle 20 is formed as a venturi type nozzle in the present embodiment. The secondary air is conveyed through the secondary air hole 22 into the combustion chamber 24. This division of the combustion air into primary air and secondary air serves to generate a rich air-fuel mixture that is easy to ignite at the outlet of the nozzle 20.

  The nozzle 20 is provided with a stabilization region 26 and a diffuser 30 in order to produce a venturi effect. A fuel needle 28 is provided in the nozzle 20. Fuel 44 is supplied from a fuel pipe 82 to the fuel needle 28. The fuel flowing out from the fuel needle 28 with almost no pressure pulls the yarn due to the high flow velocity of the combustion air in the stabilization region 26. This filamentous fuel then becomes small particles. The high air velocity required for good spraying can be achieved by good pressure recovery of the diffuser 30.

  Furthermore, the flow rate of the fuel / air mixture rapidly decreases along the diffuser 30. Thereby, a low flow rate can be realized in the range of the glow plug 62 shown in FIG. This promotes the formation and diffusion of fire. After start-up, ie after ignition of the system by the glow plug 62, the glow plug 62 is switched off. Thereafter, the glow plug 62 acts as a flame monitor by measuring resistance.

  A collision plate 32 is disposed in the combustion chamber 24. Since the impingement plate 32 is a flow obstruction, the air exiting the nozzle 20 is forcibly guided outward. Thereby, primary air and secondary air mix well. This is effective from the viewpoint of good combustion. Accordingly, the range between the nozzle 20 and the collision plate 32 serves as the mixing region 34, and the range beyond the collision plate 32, that is, the region located downstream of the collision plate 32 serves as the reaction region. The generated air-fuel mixture burns in the inner cylinder 40 and is guided out of the heating device 10 through a portion for guiding the exhaust. The generated low-temperature water 46 is heated by exchanging heat with the portion that guides the exhaust gas, so that the high-temperature water 48 flows out of the heating device 10. For example, air can be used as the heat medium instead of water.

  FIG. 2 is a side view showing the embodiment of the nozzle 20 partially cut away. Such a nozzle 20 can be used in, for example, a heating apparatus 10 as shown in FIG. The nozzle 20 is made from a ceramic material. This simplifies the production of the nozzle 20 compared to a metal nozzle. The nozzle 20 includes an air inflow range 50 and an air outflow range 52. The air inflow range 50 is connected to the air outflow range 52 via a flow path 54. In the present embodiment, the flow path 54 is divided into the stabilization region 26 and the diffuser 30. Air guiding means 56 is provided in the air inflow range. The air guiding means 56, that is, the air guiding element 56 is formed integrally with the ceramic nozzle 30. The air guide element 56 turns the supplied air, that is, imparts angular momentum to the air. This will be described in detail later with reference to FIG. Since the fuel needle 28 (see FIG. 4) is disposed within the stabilization range 26, the fuel / air mixture flows out from the nozzle 20. This air-fuel mixture can be ignited by a glow plug 62 that can be inserted into the hole 58 of the nozzle 20. Since the glow plug 62 is held by the hole 58 of the nozzle 20, that is, particularly not held by any other component, the position of the glow plug 62 is fixed with respect to the nozzle 20. Therefore, the installation position of the glow plug 62 is kept at a very small error. Advantageously, the hole 58 extends through the enlarged cylindrical projection 64 of the nozzle 20. This has the advantage that the flow state of the nozzle 20 is not significantly affected by the hole 58 or the glow plug 62 disposed in the hole 58.

  FIG. 3 is a plan view of the air inflow range 50 of the nozzle. The structure of the air inflow range 50 by the air guide element 56 is shown. The air guide element 56 forms a plurality of passages 60 for the incoming air. The passage 60 is positioned so that there is a deviation with respect to the radial direction of the structure disposed substantially on one axis. Therefore, the air flowing from the outside is subjected to a swirling action. This provides advantageous properties with respect to the spraying of the fuel flowing out of the fuel needle located within the stabilization range 26. Furthermore, the arrangement structure of the hole 58 for accommodating the glow plug 62 is shown. This hole penetrates the substantially cylindrical protrusion 64. The protrusion 64 further includes a notch 66. This notch 66 defines the position where the nozzle 20 is assembled. This will be described in detail later with reference to FIG.

  FIG. 4 shows a partially cut away view of the device according to the invention. The end of the burner 12 near the nozzle 20 is shown. The burner 12 is defined by a heat shield 78. In the case of the present embodiment, the heat shield 78 is provided with two assembly bolts 68. The assembly bolt 68 can be welded to the heat shield 78 or the burner 12. The assembly bolt 68 positions other components described later. As another component, first, a seal 76 is provided. This seal 76 preferably comprises a mica layer and a graphite layer. In this case, the mica layer is provided near the burner 12 and the graphite layer is provided near the nozzle 20. Subsequently, a ceramic nozzle 20 is provided. The ceramic nozzle 20 is attached to the assembly bolt 68 so as not to rotate by the notch 66 shown in FIG. A fuel supply member 70 connected to the fuel needle 28 is attached to the nozzle 20. The fuel supply member 70 is similarly positioned by the assembly bolt 68 using a hole 84 provided in the side flange. Fuel is supplied from a fuel pipe 82 to the fuel supply member 70. A fuel sensor 80 is disposed in the fuel pipe 82. A spring 72 is provided following the fuel supply member 70. This spring 72 is similarly attached to the assembly bolt 68. The spring 72 is held by a clamping disk 74 that is mounted so as not to move on the assembly bolt 68. The spring 72 is shown in tension. In this tensioned state, the legs of the spring 72 are, for example, parallel to the disc between them. In the relaxed state of the spring 72, the legs of the spring 72 are bent upward toward the disc between them. The glow plug not shown in FIG. 4 is positioned by this nozzle 20 and held by a wire spring (not shown) supported by the nozzle 20 in the same manner as the embodiment of the nozzle 20 shown in FIG. .

  As a result, the fuel supply member 70 and the fuel needle 28 are automatically adjusted to the correct position with respect to the nozzle 20. Therefore, since only two parts that affect the fuel supply and the mixing of fuel and combustion air are involved in this alignment, very small errors can be maintained. This is possible by axial assembly on a common assembly bolt 68. Similarly, the glow plug 62 can be accurately positioned with respect to the nozzle 20 and the burner 12. The production of the structure shown in FIG. 4 can be completely automated. In particular, since the assembly directions are all axial, the parts 76, 20, 70, 72 and 74 need only be "passed" through the assembly bolts. The seal 76 performs a heat insulating action, a connecting action of the nozzle ceramic 20 to the metal of the heat shield 78 and an error correcting action. Since the structure can be advantageously assembled by controlling the clamping force of the clamping disk 74 against the assembly bolt 68, uniform preconditions can be made regarding the thermal and temperature characteristics of the structure. Errors due to different heating of the components, different final temperatures of the components and different coefficients of thermal expansion can be corrected by the spring force of the spring 72.

  The features of the invention disclosed above, in the drawings and in the claims are important for realizing the invention both individually and in any combination.

It is a schematic fragmentary sectional view of the heating apparatus which can apply this invention. It is a side view which cuts and shows an embodiment of a nozzle by the present invention partially. It is a top view of the air inflow range of the nozzle by this invention. FIG. 2 shows a nozzle according to the invention attached to a burner.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Heating device, 12 ... Burner, 14 ... Annular passage type fan, 16 ... Air inflow pipe, 18 ... Combustion air collection chamber, 20 ... Nozzle, 22 ... Secondary air hole, 24 ... Combustion chamber, 26 ... Stabilization region 28 ... Fuel needle, 30 ... Diffuser, 32 ... Impact plate, 34 ... Mixing region, 36 ... Fan motor, 38 ... Reaction region, 40 ... Inner cylinder, 42 ... Combustion air, 44 ... Fuel, 46 ... Inflowing low temperature 48 ... warm water flowing out, 50 ... air inflow range, 52 ... air outflow range, 54 ... flow path, 56 ... air guide element, 58 ... hole, 60 ... passage, 62 ... glow plug, 64 ... protrusion , 66 ... Notch, 68 ... Assembly bolt, 70 ... Fuel supply member, 72 ... Spring, 74 ... Tightening disc, 76 ... Seal, 78 ... Thermal shield, 80 ... Fuel sensor, 82 ... Fuel pipe, 84 ... (70 Hole)

Claims (10)

Air inflow range (50);
Air outflow range (52);
In a nozzle for spraying liquid fuel with air flowing through a nozzle (20), having a flow path (54) connecting the air inflow range (50) and the air outflow range (52),
The nozzle (20) is made of a ceramic material;
Air guide means (56) for swirling the inflowing air is provided in the air inflow range (50);
The nozzle characterized in that the air guiding means (56) is formed integrally with the nozzle (20).   A nozzle according to claim 1, characterized in that the nozzle (20) comprises means (58) for holding a glow plug (62). At least a portion of the nozzle (20) has a generally cylindrical shape;
3. Nozzle according to claim 1 or 2, characterized in that the air guiding means (56) form a passage (60) offset in the radial direction.   4. A nozzle as claimed in any one of the preceding claims, characterized in that the air guiding means (56) has a substantially triangular bottom and rounded corners.   5. A nozzle according to any one of claims 1 to 4, characterized in that the air guiding means (56) are formed as vanes.   6. A nozzle according to any one of claims 2 to 5, characterized in that the means for holding the glow plug (62) is formed as a hole (58) extending obliquely with respect to the cylinder axis. . At least a substantially cylindrical portion of the nozzle (20) is provided with a substantially cylindrical protrusion (64) having an enlarged diameter;
The means for holding the glow plug (62) is formed as a hole (58) extending obliquely with respect to the cylindrical axis and penetrating the protrusion (64). The nozzle as described in any one. At least a substantially cylindrical portion of the nozzle (20) is provided with a substantially cylindrical protrusion (64) having an enlarged diameter;
A nozzle according to any one of the preceding claims, characterized in that the cylindrical projection (64) is provided with a notch (66) for receiving an assembly bolt (68).   A nozzle according to any one of the preceding claims, characterized in that the nozzle (20) is a venturi type nozzle.   In a heating device (10) for mobile applications, in particular for motor vehicles, comprising a burner (12) for combusting a mixture of fuel and air, the burner (12) comprising a nozzle (20) 20) is the nozzle as described in any one of Claims 1-9, The heating apparatus characterized by the above-mentioned.

Images