EP1342951A2 - Mobile heating apparatus with fuel inlet - Google Patents

Abstract

The mobile heater has a fuel supply with which a gaseous fuel or a liquid fuel can be alternatively fed to an atomizing burner (14) with a small Venturi tube (98) via which both the liquid and gaseous fuel can be delivered. The Venturi tube has an internal diameter of 1 to 2 mm, especially 1.5 mm. AN Independent claim is also included for the following: a vehicle with an inventive device.

Description

Background of the Invention

The invention relates to a mobile heater, in particular for a vehicle, with a fuel supply, by means of which gaseous or liquid fuel can optionally be supplied to a combustion device. The invention further relates to a vehicle with such a mobile heater.

Mobile heaters of this type are used as a so-called additional air heater or additional water heater in vehicles, such as, for example, passenger cars, commercial vehicles, buses or ships, and above all also in camping and caravan vehicles and motorhomes. They are usually used to heat a vehicle compartment or to preheat the cooling water of an internal combustion engine.

A mobile heater, the combustion device of which can be supplied with either gaseous or liquid fuel, is intended to make its user independent of a local energy supply and to allow him to use several different types of fuel to heat his vehicle. In particular, a freely selectable operation with a liquid fuel, such as diesel, and a gaseous fuel, such as propane or butane, should be possible.

In connection with a water cycle, such mobile heaters can fundamentally improve the air conditioning and heating comfort of the vehicles mentioned considerably. The disadvantage of today's mobile heaters, however, that they can only be converted in a complex manner between operation with liquid or gaseous fuel.

DE 100 24 566 C1 discloses a mobile heating system, in particular for motor vehicles, which is provided with two fuel stores and a combustion device which is designed for operation with gaseous and / or liquid fuels. In order to supply the combustion device, a switchover arrangement is provided, with which the fuel device can also be supplied with liquid fuel instead of gaseous one. In DE 100 24 566 C1, however, there is no indication of how the combustion device itself should be designed.

From 197 40 062 A1 a heating arrangement in a motor vehicle with an internal combustion engine is known, in which an additional heater or an auxiliary heater or part of the additional or auxiliary heater is designed as a modular component which is arranged or connected to vehicle-specific interfaces of the heating arrangement and, if appropriate, against another such modular component is interchangeable. In this way, an individual original or subsequent configuration of a heating arrangement in a particular motor vehicle should be possible, inter alia with regard to the fuel operating mode.

From DE 36 04 314 A1 a heater is known which can be converted from operation with liquid fuel to operation with gaseous fuel without any significant conversion measures. For this purpose, a gas burner conversion insert is provided on the heater, which is inserted into the combustion chamber instead of a burner operated with liquid fuel. This gas burner conversion insert expediently forms the rear wall of the combustion chamber of the heater. Furthermore, the gas burner conversion insert contains a gas mixing device to which combustion air is supplied by a combustion air fan. The gas mixing device is designed in the form of a pot-shaped housing, on which a feed section is provided, through which primary combustion air and gas are passed become. Alternatively, the gas mixing device can be formed by an injector that is attached to a cover that forms the rear wall of the combustion chamber. An injector body of the injector comprises an injector section, an adjoining venturi section and a diffuser section.

Underlying task

The invention has for its object to improve a vehicle with a heater of the type mentioned so that an alternative operation with both a liquid and a gaseous fuel is essentially possible without additional measures.

Solution according to the invention

This object is achieved according to the invention with a mobile heater of the type mentioned at the beginning, in which the combustion device is designed as an atomizing burner with a Venturi tube and both the gaseous and the liquid fuel can be supplied through the Venturi tube. Furthermore, the object is achieved with a generic heater in which the combustion device is designed as an atomizing burner with a Venturi tube and the liquid fuel can be fed through the Venturi tube, and an annular space is formed around the Venturi tube through which the gaseous fuel can be fed. Finally, the object is also achieved with such a heater, in which the combustion device is designed as an atomizing burner with a Venturi nozzle, in front of which a combustion chamber extends in the flow direction of combustion gases, and at the transition from the Venturi nozzle to the combustion chamber essentially transversely to the flow direction of the combustion gases Grid is arranged, and with a vehicle which is provided with such a mobile heater according to the invention.

The vehicle according to the invention and its heating device are based on the knowledge that if the combustion device of a heating device is skillfully designed, liquid or gaseous fuel can be supplied to the heating device without complex conversion or replacement measures on components or modules. At the same time, an excellent combustion quality can be guaranteed for both types of fuel.

In order to implement this finding in a mass-produced product which is inexpensive to produce, substantial changes or improvements have been made to several elements of a combustion device. As the starting point, a burner has been specifically chosen, as described in the non-prepublished German patent application DE 101 44 408.7. The combustion device is designed as an atomizing burner, which is known in principle for operation with liquid fuels. According to the invention, a venturi tube of such an atomizing burner is adapted so that gaseous fuel can also be supplied to it. It has surprisingly been found that the gaseous fuel burns excellently in the atomizing burner.

As an alternative or in addition, in a heating device according to the invention, an annular space is formed around a venturi tube of an atomizing burner through which gaseous fuel can be supplied. Alternatively, liquid fuel can be supplied through the venturi tube itself. The operating mode of this heater can also be changed without the need for conversion.

Finally, it is provided in a heating device according to the invention that it is provided with a Venturi nozzle, in front of which a grid extends transversely. This inexpensive and simple grid has a positive effect, in particular when the combustion device is operated with a gaseous fuel the premixing of fuel with the primary air supplied. This in turn leads to an improved quality of combustion. Under certain circumstances, the grid makes it possible for conventional Venturi burners to be operated with a liquid or gaseous fuel without conversion measures with good combustion values.

The inventive design of a heater on a vehicle offers a variety of new and innovative uses. New fields of application are particularly open in the camping, caravan and motorhome market. For example, the user of the heater becomes more independent of supply shortages of individual fuels, some of which exist abroad. In conjunction with a water heating circuit, a significant improvement in the heating of vehicle rooms is possible. For example, Heating convectors can be arranged in all sections of the vehicle. This ensures uniform heating of the vehicle compartment and prevents condensation. A floor heating system and a domestic hot water boiler can also be integrated into the heating circuit.

Advantageous developments of the invention

In an advantageous development of the invention, the venturi tube is designed with an inner diameter of 1 mm to 2 mm, in particular of 1.5 mm. This dimensioning of a Venturi tube has proven after intensive investigations to be a particularly suitable and at the same time simple design for operation with the fuel supply systems customary in today's vehicles. The dimensioning is particularly adapted to the pressure conditions when supplying both liquid and gaseous fuel.

In the case of a heater with an annular space on the venturi tube, the mixing of the supplied gas and primary air can be continued improve in that in the flow direction of the gaseous fuel behind the annular space at least one gas channel extending obliquely to the direction of the Venturi tube is formed.

For further optimization and improved processing of the gases to be burned, the combustion device of the heating devices according to the invention should advantageously be provided with swirl grooves for supplying primary air, and the gaseous fuel should, in particular through the at least one obliquely extending gas channel, at the outlet of the swirl grooves for primary air into the latter be introduced.

The grid arranged in the heater according to the invention is particularly advantageously designed as a close-meshed metal grid, in particular made of brass. The grille leads to a relatively strong accumulation effect and therefore a particularly long mixing of the fuel gases in front of the combustion chamber. Brass is particularly suitable for the production of a finely structured network or grid and, as a sufficiently temperature-resistant material, can also withstand the high temperatures in the combustion chamber over the life of the heater.

Brief description of the drawings

• Fig. 1 eine Prinzipskizze eines erfindungsgemäßen Heizgerätes mit einer Brennstoffversorgung für flüssigen oder gasförmigen Brennstoff,
• Fig. 2 einen Längsschnitt einer Brenneinrichtung eines erfindungsgemäßen Heizgerätes, an dem erfindungsgemäß wesentliche Elemente veranschaulicht sind,
• Fig. 3 eine perspektivische Gesamtansicht einer Brenneinrichtung eines ersten Ausführungsbeispiels eines erfindungsgemäßen Heizgerätes gemäß III-III in Fig. 2,
• Fig. 4 eine perspektivische Ansicht eines rückseitigen Bauteils der Brenneinrichtung gemäß IV-IV in Fig. 3,
• Fig. 5 eine perspektivische Gesamtansicht einer Brenneinrichtung eines zweiten Ausführungsbeispiels eines erfindungsgemäßen Heizgerätes gemäß V-V in Fig. 2,
• Fig. 6 eine perspektivische Ansicht eines rückseitigen Bauteils der Brenneinrichtung gemäß VI-VI in Fig. 5,
• Fig. 7 eine perspektivische Ansicht eines ersten Einzelteils des rückseitigen Bauteils gemäß VII-VII in Fig. 6, und
• Fig. 8 eine perspektivische Ansicht eines zweiten Einzelteils des rückseitigen Bauteils gemäß VIII-VIII in Fig. 6.

Exemplary embodiments of a heating device according to the invention are explained in more detail below with the aid of the attached schematic drawings. It shows:

• 1 is a schematic diagram of a heater according to the invention with a fuel supply for liquid or gaseous fuel,
• 2 shows a longitudinal section of a combustion device of a heating device according to the invention, on which essential elements are illustrated according to the invention,
• 3 shows an overall perspective view of a combustion device of a first exemplary embodiment of a heating device according to the invention according to III-III in FIG. 2,
• 4 shows a perspective view of a rear component of the combustion device according to IV-IV in FIG. 3,
• 5 shows an overall perspective view of a combustion device of a second exemplary embodiment of a heating device according to the invention according to VV in FIG. 2,
• 6 is a perspective view of a rear component of the burner according to VI-VI in FIG. 5,
• 7 shows a perspective view of a first individual part of the rear component according to VII-VII in FIG. 6, and
• 8 shows a perspective view of a second individual part of the rear component according to VIII-VIII in FIG. 6.

Detailed description of the exemplary embodiments

In Fig. 1, a heater 10 is illustrated in longitudinal section, the essential components having a combustion air blower 12, a burner 14 with a glow plug or flame detector 16 on a combustion chamber 18 and a heat exchanger 20 for a liquid heat transfer medium.

The heater 10 is coupled to a fuel supply 22, by means of which both the gaseous fuel in the form of propane and the liquid fuel in the form of diesel can be supplied to the combustion device 14.

The fuel supply 22 has a partial area for the gas supply which is connected “on site” to a liquid container 24 for liquid gas with a bottle shut-off valve 26 and a pressure regulator 28. The actual gas supply to the heater 10 begins at a gas connection 30 with a gas line 32, in which a filter 34, a device shut-off valve 36, a power control valve 38 and a throttle 40 are arranged in succession in the flow direction of the gas. A parallel line 42 extends to the power control valve 38 and the throttle 40, in which a throttle 44 is arranged.

In the direction of flow behind the confluence of the parallel line 42 in the gas line 32, a gas pressure switch 46 is connected to it and a first safety shut-off valve 48 and a second safety shut-off valve 50 are connected in series. The gas line 32 ends at a node 52 located behind it. A fuel feed line 54 leads from the node 52 to the combustion device 14 of the heater 10.

A diesel connection 56 is provided for supplying diesel to the heater 10, to which diesel fuel can be conveyed from a tank by a diesel pump (not shown). A diesel line 58 leads from the diesel connection 56 to a throttle 60 and further to a damper 62. With the throttle 60, the fuel volume flow generated by a metering pump, not shown, is limited to the maximum heating power of the heater. The downstream throttle 62 reduces pressure surges in the fuel supply line and enables a uniform fuel flow. In the direction of flow behind this damper 62, a "diesel mode" changeover valve 64 is arranged in the diesel line 58. The diesel line 58 ends at the junction 52, from where the fuel supply line 54, depending on the heater variant, either in the form of a single tube as a gas-diesel line or in the form of two separate tubes as a gas line and as a diesel line leads to the burner 14 of the heater 10.

A combustion air line 66 with an intake silencer 68 and a combustion air pressure switch 70 (negative pressure), alternatively or additionally, a combustion air pressure switch 72 (excess pressure), a heat transfer line 74, a heat transfer line, not shown, and an exhaust gas line 76 with an exhaust gas silencer 78 are connected to the heater 10 as further connections.

Two electrical switches 80 and 82 are operationally coupled to the heater 10, of which a first switch 80 is used to switch the entire heater 10 on and off and the second switch 82 enables switching between operation with diesel fuel and operation with propane gas.

2, the combustion device 14 is illustrated in more detail with its glow plug or flame monitor 16 and the combustion chamber 18.

The combustion chamber 18 is delimited by an essentially cylindrical combustion tube 84, in the interior of which a baffle plate 86 is arranged. A support disk 88 protrudes inward at the left end of the combustion tube 84 in relation to FIG. 2. In the support disk 88, a plurality of openings 90 are regularly distributed over the circumference, through which secondary air can be conveyed into the combustion chamber 18 with the aid of the combustion air blower 12 during operation of the combustion device.

On the support disk 88, an essentially circular cylindrical nozzle stock or a Venturi nozzle 92 for an atomizing burner is held, in the center of which a funnel-shaped opening 93 opening towards the combustion chamber 18 is formed. Such a nozzle assembly 92 is described in the unpublished German patent application DE 101 44 408.7. A clamp or cap 94 is pushed onto the left end of the nozzle assembly 92 in relation to FIG. 2.
A fuel feed assembly 96 abuts the clamp 94, two variants of which are illustrated in FIGS. 3 to 8.

In Fig. 2, both variants of this fuel supply assembly 96 are shown together in a simplified manner.

An arrow A illustrates a first variant in which both diesel fuel and propane gas are conveyed through a single tube of a fuel feed line 54 to a specially designed Venturi tube 98.

The arrow A together with an arrow B illustrates a second variant in which the diesel fuel is conducted separately from the propane gas through two pipes of a fuel feed line 54 to the combustion device 14. These two pipes are used alternatively. The diesel fuel is supplied through a venturi tube 98. The propane gas is supplied via an annular space 100 formed in the fuel supply assembly 96, from which it exits into a primary air flow through a plurality of gas channels 102 which run obliquely to the longitudinal axis of the combustion device 14 at the end of swirl grooves 104. The swirl grooves 104 are regularly distributed on the end face of the nozzle assembly 92 over its circumference and each extend obliquely-radially from the outside inwards to the funnel-shaped opening 93 in the nozzle assembly 92. The primary air is conveyed by means of the combustion air blower 12 through the swirl grooves 104.

On the end face of the nozzle assembly 92 facing the combustion chamber 18, a close-meshed grating 106 made of brass is arranged essentially transversely to the longitudinal axis of the combustion device 14 in front of its funnel-shaped opening 93.

The liquid or gaseous fuel introduced into the funnel-shaped opening 93 of the nozzle assembly 92 mixes with the primary air to form a combustible mixture. The mixture is dammed up in front of the grating 106 and further mixed due to the inflowing fuel and the inflowing primary air. The mixture passes through the grid 106 into the combustion chamber 18, where it is at the glow plug or

Flame detector 16 can be ignited and burned.

3 and 4 illustrate the first variant of a combustion device 14, in which both the liquid and the gaseous fuel can be supplied through one and the same specially designed Venturi tube 98.

In the combustion device 14, the fuel supply assembly 96 is fastened to the support disk 88 together with the nozzle assembly 92 by means of two pins 108 and a spring plate 110. The fuel supply assembly 96 is configured with a gas-diesel supply disc 112 in which two holes 114 are formed for the passage of the pins 108. A web 116 is formed on the outward-facing side of the gas-diesel supply disk 112, which extends essentially diametrically over the gas-diesel supply disk 112. A tubular gas-diesel supply line 118 of the fuel supply line 54 is connected to the web 116. A channel 117, shown in broken lines in FIG. 4, extends inside the web 116 and leads to the Venturi tube 98. The venturi tube 116 protrudes on the inside of the gas-diesel supply disk 112 in the direction of the funnel-shaped opening 93 of the nozzle assembly 92 and is designed with an inner diameter d of 1.5 mm, which is specifically designed for the pressure conditions for the optional supply of diesel fuel or propane gas is designed.

5 to 8 illustrate the second variant of a combustion device 14 in which diesel fuel and propane gas can be supplied through separate lines. In this variant, the fuel supply assembly 96 is designed with a two-part disc in the form of a gas supply disc 120 and a diesel supply disc 122. A tubular gas supply line 124 and a diesel supply line 126 are each individually connected to these disks 120 and 122. The two disks 120 and 122 are in contact with one another by means of pins 108 and fastening elements 128 screwed thereon in the form of nuts together with a conventional nozzle assembly 92 on the support disk 88 attached.

A conventional venturi tube 98 protrudes from the side of the diesel supply disk 122 facing the nozzle assembly 92, and can be supplied with diesel fuel through a web 116 on the side of the diesel supply disk 122 facing away from it. In the case of the diesel supply disk 122 illustrated in particular in FIG. 7, the web 116 extends essentially only into the center of the disk 122. Around the end of the web 116 there are several gas openings or gas channels in the center of the diesel supply disk 122 102 formed obliquely to the longitudinal axis of the Venturi tube 98. These gas channels 102 are also illustrated in FIG. 2.

In the gas supply disk 120, a radially inwardly projecting groove 130 is formed, in which the web 116 is received when the disks 120 and 122 are assembled. The fit between the web 116 and the 130 groove is gas-tight. In the center of the gas supply disk 120, on the side facing the diesel supply disk 122, the above-mentioned annular space or annular channel 100 is formed, which is also illustrated in FIG. 2. A bore 132 passes through the gas supply disk 120 from the outside inwards, essentially tangentially to the lateral surface of the annular space 100. The gas feed line 124 is connected to the bore 132.

In the assembled state of the two disks 120 and 122, gas can be fed into the annular space 100 through the gas supply line 124 and the bore 132. The gas exits the annulus 100 through the gas channels 102 over the outer circumference of the venturi tube 98 at the diesel supply disk 122 (see FIG. 6). It reaches the swirl grooves 104 at this outlet, where it is mixed with the supplied primary air (see FIG. 2).

LIST OF REFERENCE NUMBERS

10

heater

12

Combustion air fan

14

burning device

16

Glow plug or flame detector

18

combustion chamber

20

Heat exchanger 10

22

fuel supply

24

Liquid container or liquid gas container

26

Flaschenabsperrventil

28

pressure regulator

30

Gas connection 15

32

gas pipe

34

filter

36

an appliance

38

Power control valve

40

Throttle 20

42

parallel line

44

throttle

46

Gas pressure switch

48

first safety shut-off valve

50

second safety shut-off valve 25

52

junction

54

fuel supply line

56

diesel connection

58

diesel line

60

Throttle 30

62

damper

64

Changeover valve diesel operation

66

Combustion air line

68

intake silencer

70

Combustion air pressure switch (negative pressure)

72

Combustion air pressure switch (overpressure)

74

Heat transfer line 5

76

Flue gas discharge

78

exhaust silencer

80

first switch

82

second switch

84

Fuel tube 10

86

baffle plate

88

support disc

90

openings

92

Nozzle block or Venturi nozzle

93

funnel-shaped opening 15

94

clip

96

Brennstoffzuführbaugruppe

98

venturi tubes

100

annulus

102

Gas channel 20

104

rifling

106

grid

108

pencils

110

spring plate

112

Gas-diesel feed disc 25

114

holes

116

web

117

channel

118

Gas-diesel supply

120

Gas feed disc 30

122

Diesel feed disk

124

Gas supply line

126

Diesel supply line

128

fasteners

130

groove

132

drilling

Claims (16)

Mobile heater (10), in particular for a vehicle, with a fuel supply (22), by means of which gaseous or liquid fuel can optionally be supplied to a combustion device (14), characterized in that the combustion device (14) is used as an atomizing burner with a Venturi tube ( 98) and both the gaseous and the liquid fuel can be supplied through the Venturi tube (98). Heating device according to claim 1, characterized in that the venturi tube (98) is formed with an inner diameter of 1 mm to 2 mm, in particular of 1.5 mm. Mobile heater (10), in particular for a vehicle, with a fuel supply (22), by means of which gaseous or liquid fuel can optionally be supplied to a combustion device (14), characterized in that the combustion device (14) is used as an atomizing burner with a Venturi tube ( 98) and the liquid fuel can be fed through the Venturi tube (98), and an annular space (100) is formed around the Venturi tube (98) through which the gaseous fuel can be fed. Heating device according to claim 3, characterized in that in the flow direction of the gaseous fuel behind the annular space (100) is formed at least one gas channel (102) which extends obliquely to the longitudinal direction of the venturi tube (98). Heating device according to claim 3 or 4, characterized in that the combustion device (14) is provided with swirl grooves (104) for supplying primary air, and the gaseous fuel, in particular through the at least one obliquely extending gas channel (102), at the outlet of the swirl grooves (104) for Primary air is introduced into this. Heating device according to one of claims 1 to 5, characterized in that the combustion device (14) is formed with a venturi nozzle (92) arranged in front of the venturi tube (98) essentially in the flow direction of fuel gases, in front of which a combustion chamber (18) extends, and a grating (106) is arranged at the transition from the Venturi nozzle (92) to the combustion chamber (18) substantially transversely to the direction of flow of the fuel gases. A heating device according to claim 6, characterized in that the grid (106) is of narrow mesh. Mobile heater (10), in particular for a vehicle, with a fuel supply (22), by means of which gaseous or liquid fuel can optionally be supplied to a combustion device (14), characterized in that the combustion device (14) is used as an atomizing burner with a Venturi nozzle ( 92), in front of which a combustion chamber (18) extends in the flow direction of fuel gases, and a grille (106) is arranged at the transition from the Venturi nozzle (92) to the combustion chamber (18) essentially transversely to the flow direction of the fuel gases. A heater according to claim 8, characterized in that a venturi tube (98) is formed on the venturi nozzle (92) and both the gaseous and the liquid fuel can be supplied through the venturi tube (98). Heating device according to claim 9, characterized in that the venturi tube (98) is formed with an inner diameter of 1 mm to 2 mm, in particular of 1.5 mm. Heater according to claim 8, characterized in that on the Venturi nozzle (92) a Venturi tube (98) is formed and the liquid fuel can be fed through the Venturi tube (98), and an annular space (100) is formed around the Venturi tube (98) through which the gaseous fuel can be fed. Mobile heater according to claim 11, characterized in that at least one gas channel (102) extending obliquely to the longitudinal direction of the venturi tube (98) is formed in the flow direction of the gaseous fuel behind the annular space (100). Mobile heating device according to claim 11 or 12, characterized in that the combustion device (14) is provided with swirl grooves (104) for supplying primary air, and the gaseous fuel, in particular through the at least one obliquely extending gas channel (102), at the outlet of the Swirl grooves (104) for primary air can be introduced therein. Mobile heating device according to one of claims 8 to 12, characterized in that the grid (106) is designed with a close mesh. Heater according to one of Claims 1 to 14, characterized in that switching means (36, 38, 64, 82) for optionally supplying the combustion device (14) with gaseous and / or liquid fuel can be coupled to the fuel supply (22). Vehicle with a mobile heater (10) according to one of claims 1 to 15.

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