MOBILE HEATING DEVICE, AND METHOD FOR OPERATING A MOBILE HEATING DEVICE

Abstract

A mobile heating device, comprising a heater assembly including a fuel chamber, and a fuel supply line for supplying liquid fuel to the heater assembly, where the heater assembly further includes an evaporator receiving arrangement for evaporating liquid fuel, said arrangement comprising an evaporator receiving body for receiving an evaporator element for distributing and evaporating liquid fuel, where the fuel supply line comprises a supply pipe with an inlet for inputting fuel and an outlet for outputting fuel to the combustion chamber, where the fuel supply line further includes an emptying device for partly or completely emptying the fuel supply line through the outlet.

Claims

1: A mobile heating device, comprising a heater assembly including a combustion chamber, and a fuel supply line for supplying liquid fuel to the heater assembly, wherein the heater assembly comprises an evaporator receiving arrangement for evaporating liquid fuel, said arrangement comprising an evaporator receiving body for receiving an evaporator element for distributing and evaporating liquid fuel, wherein the fuel supply line comprises a supply pipe having an inlet for inputting fuel and an outlet for outputting fuel to the combustion chamber, wherein the fuel supply line further comprises an emptying device for at least one of: partially and completely emptying the fuel supply line through the outlet.

2: The heating device according to claim 1, wherein the emptying device comprises a nucleating device including one or more of: at least one rough and at least one structured nucleation surface for forming boiling bubbles.

3: The heating device according to claim 2, wherein the nucleation surface is arranged on at least one of: an inner circumferential surface of the supply pipe, arranged on an inner surface of a connecting piece arranged at the inlet of the supply pipe, and arranged in a component inserted into the fuel supply line, wherein the nucleation surface extends in particular over the entire inner circumferential surface of the supply pipe.

4: The heating device according to claim 2, wherein a further element is arranged in the fuel supply line, in the supply pipe, the further element having the nucleation surface, wherein the further element is formed as a displacement wire.

5: The heating device (100) according to claim 2, wherein the nucleation surface has been produced by at least one of: means of mechanical deformation, means of applying a coating, means of milling, and means of an etching process.

6: The heating device according to claim 3, wherein the supply pipe comprises a first supply pipe and a second supply pipe and the component is at least one of: arranged between the first supply pipe and the second supply pipe and wherein the component comprises one or more bodies arranged therein, wherein at least one of the bodies comprises one or more of: glass and ceramics, wherein a surface of at least one of the bodies forms are part of the nucleation surface.

7: The heating device according to claim 1, wherein the emptying device comprises a heat supply element that is arranged on at least one of: an outer circumferential surface of the supply pipe (5) and an outer surface of a connecting piece arranged at the inlet of the supply pipe.

8: The heating device according to claim 7, wherein the heat supply element comprises an active heating element.

9: The heating device according to claim 7, wherein the heat supply element comprises a passive heat conducting element which conducts heat from a heat source to at least one of: the outer circumferential surface and outer surface, wherein the passive heat conducting element comprises, a hose clamp.

10: The heating device according to claim 1, wherein the fuel supply line is configured to extend from a fuel source to the heating device as a fuel supply to the heating device, wherein the fuel supply line comprises a first zone and a second zone, wherein the fuel supply line further comprises a back-suction device in the first zone, wherein the back-suction device comprises a fuel reservoir, wherein the back-suction device is designed to suck back fuel from the second zone into the first zone by means of a change in volume of the fuel reservoir.

11: The heating device according to claim 10, wherein the fuel reservoir is formed by at least one cavity and at least one movable piston, such that the fuel sucked back from the second zone can be received at least partially in the fuel reservoir.

12: The heating device according to claim 9, wherein the back-suction device comprises a controller.

13: The heating device according to claim 1, wherein the fuel supply line is welded to the evaporator receiving body.

14: A method for operating a mobile heating device with an evaporator burner, wherein a complete or partial emptying of a fuel supply line of the heating device takes place, wherein the heating device comprises a supply pipe with an inlet for inputting fuel and an outlet for outputting fuel to a combustion chamber, the method comprising the following steps: initiating the termination of a heating process, terminating a fuel supply through the inlet of the supply pipe, forming boiling bubbles in the fuel on a nucleation surface and transferring at least a portion of the fuel present in the fuel supply line into the combustion chamber by means of the boiling bubbles, and burning the transferred portion of the fuel in the combustion chamber.

15: The method according to claim 14, further comprising: back-sucking fuel remaining in a second zone of the fuel supply line into a first zone of the fuel supply line, by a volume change of a fuel reservoir arranged in the first zone of the fuel supply line.

16: The method according to claim 15, wherein the method comprises, after the back-sucking, the steps of: initiating another heating process with the heating device; pushing out the fuel from the fuel reservoir into the fuel supply line; pushing out at least a portion of the pushed-out fuel.

17: The method according to claim 16, wherein pushing out at least the portion of the pushed-out fuel comprises pushing out all of the pushed-out fuel.

18: The heating device according to claim 11, wherein the fuel reservoir is formed by at least one deformable supply line section, arranged in series in the fuel supply line, such that the fuel sucked back from the second zone can be received at least partially in the fuel reservoir.

19: The heating device according to claim 9, wherein the back-suction device is connected to a controller.

Description

DETAILED DESCRIPTION

[0059] FIG. 1 shows an evaporator receiving arrangement as part of a heating device 100 in a first configuration. The evaporator receiving arrangement includes an evaporator receiving body 2 and a portion of the fuel supply line 4. The evaporator receiving body 2 is configured to receive an evaporator element 3 for distributing and evaporating liquid fuel. For example, an evaporator element 3 may be formed of a metal mesh or a porous material having a large surface area. The evaporator receiving body 2 has a bottom portion 6 and a peripheral wall 8 having a plurality of air supply openings 41. In particular, the air supply openings 41 may be arranged in the peripheral wall 8 in one or more rows.

[0060] The evaporator element 3 can be inserted and fixed in the evaporator receiving body 2 by means of a fixing element 40, as shown in the exploded view in FIG. 2.

[0061] A recess 42 for a glow plug is further provided in the peripheral wall 8 of the evaporator receiving body 2.

[0062] The fuel supply line 4 comprises a supply pipe 5. In this regard, the fuel supply line 4 and the supply pipe 5 may be integrally or materially bonded to each other in one embodiment example. In an alternative embodiment example, fuel supply line 4 and supply pipe 5 may (initially) be separate modules that are joined together (during assembly). For example, supply pipe 5 and fuel supply line 4 may be inserted (plugged) into each other, at least in sections, and sealingly connected. The supply pipe 5 has an inlet 14 and an outlet 16. The inlet 14 is provided with a connecting piece 18 and the outlet 16 of the supply pipe 5 opens centrally into the bottom region 6 of the evaporator receiving body 2. In the embodiment shown, the supply pipe 5 is welded to the evaporator receiving body 2.

[0063] The fuel supply line 4, in particular the fuel supply pipe 5, is provided with a nucleating device 20. FIG. 3 shows a first configuration of a nucleating device 20. The fuel supply pipe 5 has an inner circumferential surface 11 and an outer circumferential surface 12. The inner circumferential surface 11 has a nucleation surface 22. In the embodiment shown here, the nucleation surface 22 extends circumferentially over the entire surface of the inner circumferential surface. Such a nucleation surface 22 has projections and/or depressions which serve as nucleation sites for heterogeneous nucleation of gas bubbles, in particular from low-boiling components of the fuel. The nucleation surface 22 is in particular a rough or structured surface as shown by way of example in FIG. 5 a to f. Here, FIG. 5a shows a surface which is provided with regular structures. This structure has essentially angular structures with peaks. In particular, it may be a knurled surface. FIG. 5b shows a first corrugated surface with a first amplitude and wavelength. FIG. 5c shows another surface provided with regular structures, which, in contrast to FIG. 5a, has flattened peaks. However, the flattening at the surface increases the number of nucleation points of each structural unit. FIG. 5d shows a surface similar to the surface in FIG. 5b, but with a lower wavelength and amplitude.

[0064] FIGS. 5e and 5f show irregular surface structures, which in FIG. 5e are shown essentially with spikes and in FIG. 5f are shown essentially with rounded structures.

[0065] FIG. 4a shows another configuration of a fuel supply line. In this configuration, a further element 24 in the form of a displacement wire 26 is arranged in the supply pipe 5. Such a displacement wire 26 extends over a portion or the entire supply pipe 5 and is fixedly mounted therein. This further element 24 is provided with a nucleation surface 22, which is in particular a rough or structured surface as shown by way of example in FIGS. 5 a to f. The nucleation surface may be formed exclusively on the further element 24, or further nucleation surfaces 22 may be present, as shown in FIG. 3. The nucleation surface 22 may be arranged on all surfaces of the displacement wire 26 extending parallel to a longitudinal axis of the displacement wire 26, or only on a portion thereof, in particular on one side or on two sides.

[0066] FIG. 4b shows another configuration of a fuel supply line. In this configuration, the fuel supply line 4 comprises a first supply pipe 5a and a second supply pipe 5b. A component 32 is connected into the fuel supply line 4. The component 32 has a cylindrical inner space. An inner diameter is shown here to be smaller than that of the first supply pipe 5a and the second supply pipe 5b. However, this is optional and could be the same or larger. On an inner surface of the component 32 is a nucleation surface 22, as in the previously described configurations. Alternatively or additionally, one or more bodies may be arranged in the component, which are preferably formed of glass or ceramic and/or are in the form of small plates, rods, sleeves, small pipes, beads and/or stones.

[0067] FIG. 6 schematically shows a configuration of an evaporator receiving device. The evaporator receiving body 2 has a central opening at the bottom, which is overlaid by the evaporator element 3. Here, the supply pipe 5 of the fuel supply line 4 in FIG. 6 is welded directly to the bottom area 6 of the evaporator receiving body 2 at the outlet 16 of the supply pipe 5.

[0068] FIG. 7 shows an example of a configuration in which a heat supply element 28 is arranged on an outer circumferential surface 12 of the supply pipe 4. The heat supply element 28 is configured in particular as a passive element or active heating element 30. Alternatively, a heat supply element 28 can also be arranged on the outer surface 19 of the connecting piece 18 shown in FIG. 1. In addition to the shown one-piece configuration of the evaporator receiving body 2 and the supply pipe 5, the supply pipe 5 can also be connected to the evaporator receiving body 2 in a known manner. For this purpose, the evaporator receiving body 2 can in particular have a pipe connection piece with a connecting device.

[0069] FIG. 8 shows a heating device 100 according to the invention with a heater assembly 1 having an evaporator burner. The reference numeral 50 denotes a fuel source, in particular a dosing pump connected to a fuel tank. The fuel supply line 4 is arranged between the fuel source 50 and the heating device 100. A connecting piece 18 is arranged at an inlet 14 of a supply pipe 5. The connecting piece 18 is further connected to a flexible conduit 48 or to a rigid conduit. The emptying device 10 is arranged in the supply pipe 5, which here exemplarily comprises a component 32 inserted into the supply pipe 5. The component 32 may comprise the nucleating device 20, as also shown in FIG. 4b. If no component 32 is provided as a separate component, the nucleating device 20 may also be provided by nucleation surfaces 22 arranged in the supply pipe 5, as shown for example in FIG. 3 or 4a. The emptying device 10 may further comprise a heat supply element 28, which is arranged in particular on the supply pipe 5, for example also alternatively to the component 32.

[0070] The evaporator receiving body 2 follows at the outlet 16 of the supply pipe 5. The evaporator receiving body 2 has a bottom area 6 and a peripheral wall 8. An evaporator element 3 is arranged in the evaporator receiving body 2. Downstream, air supply openings 41 are arranged in the peripheral wall 8, by means of which combustion air is supplied to the combustion chamber 9. The combustion air can, for example, be directed in a region around the supply pipe 5 into an antechamber 43 and then via a further chamber 44 to the air supply openings 41 and further into the combustion chamber 9. Heat exchanger and an exhaust duct are not shown.

[0071] The size ratios and pipe lengths shown are not limiting, but can be adapted to actual lengths and size ratios. In particular, the pipes can also have bends, which may be necessary during installation, for example, in a vehicle.

[0072] FIG. 9 illustrates the sequence of the method according to the invention. In step a), a termination of a heating process is initiated. This can be done, for example, by a user inlet command or time-controlled.

[0073] In step b), the fuel supply through the inlet 14 of the supply pipe 5 is terminated. For this purpose, in particular an upstream dosing pump can be switched off or an upstream shut-off valve can be closed. Thus, a flow rate of the fuel is reduced.

[0074] After step b), boiling bubbles are formed in the fuel in step c), in particular on a nucleation surface 22, and at least some of the fuel in the fuel supply line is transferred to the combustion chamber 9 by means of the boiling bubbles. Thereby, boiling bubbles are formed homogeneously by a heat supply, for example, via the waste heat of the burner and, if necessary, one or more heat supply elements 28 and/or heterogeneously at the rough or structured nucleation surface 22. This heating of the fuel only has an effect at the lower flow rate of the fuel. The formation of boiling bubbles leads to an increase in volume of the fuel in the fuel supply line 4, in particular the supply pipe 5, so that fuel is forced through the outlet of the supply pipe 5, in particular into an evaporator element. In step d), the transferred part of the fuel is burned in the combustion chamber 9 of the heating device. Thus, the fuel supply line is at least partially emptied.

[0075] In FIG. 10, an embodiment example of a fuel supply line 4 of a heating device 100 with a back-suction device 60 is shown. Here, the heating device 100 is connected to a fuel source 50.

[0076] The fuel supply line 4 extends from a fuel source 50 to a heater assembly 1. Thereby, the fuel supply line 4 is formed as a fuel supply of the heater assembly 1 extending from the fuel source 50 to the heater assembly 1 to supply the heating device 100 with fuel B from the fuel source 50.

[0077] The heater assembly 1 as well as the fuel supply line 4 is principally as described in the embodiment examples before.

[0078] The fuel source 50 comprises a fuel tank 51 and a dosing pump 52.

[0079] The fuel tank 51 is filled or fillable with fuel B. This fuel B can be supplied from the fuel tank 51 to the fuel supply line 4 by the dosing pump 52, to be conveyed to the heater assembly 1 via the fuel supply line 4.

[0080] In this embodiment example, the fuel supply line 4 has a first zone 4a and a second zone 4b. In FIGS. 10 to 14, a separation of the two zones 4a, 4b is illustrated by a thick dashed black line. In particular, the supply pipe with a nucleation device is arranged in the zone 4b.

[0081] In the first zone 4a of the fuel supply line, the fuel back-suction device 60 is arranged, which comprises a fuel reservoir V.

[0082] The back-suction device 60 is designed to suck back fuel B from the second zone 4b, into the first zone 4ain particular at least largely into the fuel reservoir Vby means of a change in volume or an increase in volume of the fuel reservoir V, in order to empty the second zone 4b essentially completely (of fuel B).

[0083] In the embodiment example according to FIG. 10, the fuel back-suction device 60 or its fuel reservoir V is formed by a cavity 61 and a piston 62 movably mounted therein.

[0084] For example, the cavity 61 and the piston 62 form a device substantially similar to the principle of a syringe.

[0085] Via a change in volume or an increase in volume of the fuel reservoir V by moving the piston 62, the fuel B can be sucked out of the second zone 4b to substantially completely empty the second zone 4b.

[0086] To move the piston 62 or to change the volume of the fuel reservoir V, the fuel back-suction device 60 may comprise at least one (electric) actuatorfor example an actuating motor.

[0087] Alternatively or additionally, the fuel back-suction device 60 may comprise an (electrical) binary switching devicefor example a magnetic switchfor moving the piston 62 or for changing the volume of the fuel reservoir V.

[0088] By means of an opposite volume change or volume reduction of the fuel reservoir V via a corresponding movement of the piston 62, the fuel B can be pushed out of the fuel reservoir V back into the fuel supply line 4 and into the second zone 4b (towards the heater assembly 1).

[0089] The change in volume of the fuel reservoir V can optionally be specifically controlled, for example by means of a control device, in such a way that an oscillating system is thereby avoided and it can be ensured that substantially all of the fuel is sucked out of (or introduced into) the second zone 4b in a controlled and defined manner and/or that no bubbles can form in the fuel B when fuel B is sucked back or pushed out. For this purpose, according to the embodiment example, the pushing out and/or the sucking back of fuel B takes place in a time window of at least 0.3 s, preferably at least 0.5 s, further preferably of at least 1 s.

[0090] Depending on the used fuel B, an inner diameter of the fuel supply line 4 may vary. For example, an inner diameter of the fuel supply lines 4 may range from 0.5 mm to 4 mm, preferably from 1 mm to 4 mm, more preferably from 1 mm to 3 mm.

[0091] A distance or a line length between the back-suction device 60 and the heater assembly 1 is at most 1 m, preferably at most 0.8 m, further preferably at most 0.6 m, in the embodiment example shown. Furthermore, preferably the second zone 4b of the fuel supply line 4 has a smaller line volume than the first zone 4a.

[0092] Overall, in this embodiment example, this results in a maximum volume change of the fuel reservoir V of the back-suction device 60 of at least 6 ml, preferably at least 8 ml, further preferably at least 10 ml.

[0093] In any case, the maximum volume change of the fuel reservoir V is dimensioned such that it holds at least the line volume of the second zone 4b.

[0094] In the embodiment example shown, the fuel back-suction device 60 is connected to the fuel supply line 4, for example, via a single T-connector, such that the fuel reservoir V forms a sub-volume of the fuel supply line 4.

[0095] In an alternative embodiment example, the fuel back-suction device 60 may be integrally formed to the fuel supply line 4.

[0096] FIG. 11 shows the embodiment example of the fuel supply line 4 described previously in connection with FIG. 10 with a back-suction device 60 in a different state. In FIG. 2, a state of the fuel supply line 4 is shown in which all of the fuel B from the second zone 4b of the fuel supply line 4 has been sucked back into the first zone 4a. In this case, the significant portion of the sucked-back fuel B is received in the fuel reservoir V of the back-suction device 60. By a significant portion of the sucked back fuel B is meant at least 80%, preferably at least 90%, further preferably at least 95% of the conduit volume of the second section 4b.

[0097] By reducing the volume of the fuel reservoir V, the fuel B can be pushed-out back into the second section 4b of the fuel supply line 4 to start a heating process with the heater assembly 1.

[0098] In an alternative embodiment example, the fuel back-suction device 60 may be arranged in the vicinity of a connection to the fuel source 50, in particular in the vicinity of the dosing pump 52. In this manner, the second zone 4b of the fuel supply line 4 is formed by an entire line section between the heater assembly 1 and the dosing pump 52. In this way, an entire line section between heater assembly 1 and dosing pump 52 can be substantially completely drained by means of the fuel return suction device 60.

[0099] FIG. 12 shows another embodiment example of a fuel supply line 4 with an alternative configuration of a back-suction device 60.

[0100] Instead of a back-suction device 60 with a cavity 61 and pistons 62 movable therein, the fuel supply line 4 according to this embodiment example has a back-suction device 60 formed by a (reversibly) deformable supply line section 63 in the fuel supply line 4.

[0101] For the principle operation and further features of the fuel supply line, explicit reference is made to the embodiment example previously described in FIGS. 10 and 11.

[0102] The deformable supply line section 63 has a form memory device, such as a form memory alloy, on a corresponding jacket section of the fuel supply line 4. Alternatively, the corresponding jacket section of the fuel supply line 4 may (directly) comprise or be formed from the form memory device.

[0103] Alternatively or additionally, the deformable supply line section 63 has at least one piezoelectric switching device for changing the volume of the fuel reservoir V.

[0104] Generally, the deformable supply line section 63 is configured to change its shape (based on a received electrical signal) and thus its volume.

[0105] In particular, the deformable supply line section 63 can thus form or enlarge or reduce a fuel reservoir V (serially in the fuel supply line 4).

[0106] In the embodiment example according to FIG. 12, a possible enlargement of the deformable supply line section 63 or of the corresponding fuel reservoir V is indicated with dashed lines.

[0107] By changing the volume or enlarging the deformable supply line section 63 or its fuel reservoir V, fuel B can be sucked back from the second zone 4b of the fuel supply line 4 into the first zone 4a (in particular largely into the fuel reservoir V).

[0108] In this way, the fuel supply line 4 with a back-suction device 60 can be formed as a single unbranched fluid line.

[0109] In FIG. 13, the fuel supply line 4 according to the embodiment example of FIG. 12 is shown in a state with enlarged fuel reservoir or enlarged deformable supply line section 63.

[0110] In this way, all of the fuel B from the second zone 4b of the fuel supply line 4 is sucked back into the first zone 4a. The significant portion of the back-sucked fuel B is thereby received in the fuel reservoir V of the back-suction device 60. By a significant portion of the back-sucked fuel B is meant at least 80%, preferably at least 90%, further preferably at least 95% of the conduit volume of the second section 4b.

[0111] By reducing the volume of the fuel reservoir V, the fuel B can be pushed-out back into the second section 4b of the fuel supply line 4 to start a heating process with the heater assembly 1.

[0112] FIG. 14 shows an embodiment example of a heating device 100 comprising a heater assembly 1 and a fuel supply line 4, which are arranged in a system.

[0113] The system may, for example, be part of a (motor) vehicle.

[0114] The heating device 100 as well as the system has a high temperature region HT and a low temperature region NT. Whereby the high temperature area HT is characterized in that in this high temperature area are arranged those devices or apparatuses that produce waste heat. In particular, such that a temperature in the high temperature region HT is above a boiling point of the used fuel B. For example, the heater assembly 1 is arranged in the high temperature region HT. In addition, the high temperature region HT may include other heat radiating devices 70, 80 such as a vehicle engine.

[0115] The low temperature zone NT is characterized in that a predominant temperature therein is below a boiling point boiling range of the used fuel B.

[0116] Thus, the second zone 4b of the fuel supply line 4 has such a length that a boiling point or boiling range of the fuel B used can be reached at least temporarily during an operation of the heater assembly 1. The first zone 4a has such a distance from the heater assembly 1 and possibly further heat sources that a temperature predominantly prevailing therein is below a boiling point or boiling range of the used fuel B. The fuel supply line 4 includes a back-suction device 60 in the first zone 4a.

[0117] The back-suction device 60 is designed to suck fuel B from the second zone 4b back into the first zone 4ain particular at least for the most part into the fuel reservoir Vby means of a change in volume or an increase in volume of the fuel reservoir V, in order to empty the second zone 4b substantially completely (of fuel B).

[0118] In this way, the back-suction device 60 can suck back the fuel B from a high-temperature zone HT to a low-temperature zone NT.

[0119] This makes it possible to avoid evaporation of fuel B remaining in the fuel supply line 4 (for example, after a heating process has ended).

[0120] Although in FIG. 15 the fuel source 50 is arranged in the low-temperature region NT, it can alternatively be outside the low-temperature region NT. The decisive factor is (only) the arrangement of the back-suction device 60 in the/one low-temperature region NT.

[0121] At this point, it should be noted that all of the above-described parts are claimed to be essential to the invention when considered alone and in any combination, especially of the details shown in the drawings.

LIST OF REFERENCE NUMERALS

[0122] 1 heater assembly [0123] 2 evaporator receiving body [0124] 3 evaporator element [0125] 4 fuel supply line [0126] 5 supply pipe [0127] 6 bottom area [0128] 8 peripheral wall [0129] 9 combustion chamber [0130] 10 emptying device [0131] 11 inner circumferential surface [0132] 12 outer circumferential surface [0133] 14 inlet [0134] 16 outlet [0135] 18 connecting piece [0136] 19 outer surface of connecting piece [0137] 20 nucleating device [0138] 22 nucleation surface [0139] 24 further element [0140] 26 displacement wire [0141] 28 heat supply element [0142] 30 heating element [0143] 32 component [0144] 40 fixing element [0145] 41 air supply opening [0146] 42 recess [0147] 43 antechamber [0148] 44 further chamber [0149] B fuel [0150] 50 fuel source [0151] 51 fuel tank [0152] 52 dosing pump [0153] 60 back-suction device [0154] V fuel reservoir [0155] 61 cavity [0156] 62 piston [0157] 63 deformable supply line section [0158] 70, 80 heat radiating device(s) [0159] 100 heating device [0160] HT high temperature range [0161] NT low temperature range