FI113460B - Apparatus for preheating diesel fuel for heating units in mobile units - Google Patents

Description

11346:

Apparatus for preheating diesel fuel for heating units in mobile units

The invention relates to an apparatus for pre-heating diesel fuel for heating devices in mobile units in a diesel fuel tank and a diesel fuel supply apparatus having a diesel fuel line disposed between and between the diesel fuel tank and the heating device.

10 Such heating devices are used, for example, in motor vehicles for heating the interior indoors and in water-cooled engines for heating the engine. Other uses include boats and also Construction machinery. Corresponding to the installation conditions and the 15 spaces to be heated, these heaters are relatively small and have only a small fuel requirement. Therefore, the fuel lines are also small in diameter. Naturally, these heating devices must operate directly at low outdoor temperatures to a reliable level. In particular, heating devices that run on diesel fuel, at low temperatures, are known to run the risk of fuel gelling leading to unavoidable malfunction of the heating device. Therefore, fuel is added to the fuel by means of flow enhancers, jelly sea buckthorn, to prevent it. In low-temperature pressurized spray boilers, pre-heating of the nozzle is sufficient, however, t »J | effective only if fuel is supplied in sufficient quantity and fluidity. This nozzle preheating requires additional electrical energy in the vehicle network and therefore should only be used during the start-up event. When the device is started, there is usually enough heat in the heater for continued use.

The drawbacks of known equipment are revealed in particular • by the need to take up electricity in the start-up mode. In addition to 35 inches, it also has a lifetime of power supply to the vehicle, which in the cold seasons is heavily loaded due to additional energy users such as vehicle heating and window heating and lighting.

The already known apparatus for heating a running diesel-5 fuel takes place according to DE 37 834 C2, which has a diesel fuel line which is partially twisted around the heater discharge line during operation of the heater to obtain a diesel fuel preheat in the diesel fuel line.

However, since only a portion of the diesel fuel line is preheated, at very low outdoor temperatures of about -22 ° C, the heater cannot be used because the "de-gelling" of the diesel fuel in the pipeline up to the diesel fuel intake to the heater is incomplete.

Based on the foregoing prior art, the object of the invention is to provide an apparatus for heating diesel fuel for heating units of the aforementioned type in mobile units, which can be commissioned by simple installation at very low outdoor temperatures from about -20 ° C.

The object underlying the invention is solved by the features of claim 1.

The object of the invention is further developed advantageously; the sub-claims 2-25.

· ,; j In particular, the heater is configured as a water heater and is connected to the first water circuit, which is a hose or pipe with a loop or coil. 30 pipeline system is routed in the diesel fuel tank in the immediate vicinity of the diesel fuel intake and includes a diesel fuel line (except> · ''! Both ends) for preheating internally or • externally tightly pressed for installation in the hose or pipe ·

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3 ri with thermal insulation of the contact area. Therefore, in practice, the entire diesel fuel line is preheated according to the heat exchange principle in the countercurrent flow of the first water cycle and then from the diesel fuel inlet to the heating device.

If diesel fuel gelling in the tank is too extensive, the diesel-water heating device may be provided in a particularly preferred embodiment of the invention by providing a separate starter device in the form of a gasoline feeder having an additional gasoline tank, gasoline line introduction of gasoline. It is known that gasoline 15 cannot gel, and even at very low operating temperatures, it can flow even in narrow gasoline lines. Thus, the heater is first supplied with gasoline to heat the first water cycle, which liquefies the diesel fuel in the diesel fuel line 20 and at the intake point in the diesel fuel tank. The continuous running of the punching device is then disabled. a petrol feeder and activating a diesel fuel feeder to continue heating the device.

> ·; Alternatively, a separate actuator for the diesel-water heating device may also be provided in the form of an electric heating device having an electric heating line arranged in the region v · of the diesel fuel intake and / or along at least a portion of the diesel fuel line.

The electric heating wire may be an electric resistance warm-30 wire that is in close contact with the fuel line. don or pump, or it may be • assembled as a unit with the fuel line or freely positioned inside the fuel line.

The electric heating may, in the preferred embodiment 35 of the invention, also be a self-regulating heating wire, * 2 4 1346 r with two parallel single wires provided with a bridging self-regulating semiconductor, wherein the heating wire is either in close contact with the diesel fuel line or itself. The advantage of this is that it is impossible to overheat the diesel fuel because the heating power is automatically adjusted depending on the temperature.

The heating wire can be simply formed by the meter, since the individual yarns run parallel and simply can be shortened. It is also very simple to provide only those parts of the diesel fuel line with a heating wire which are actually necessary for optimal heat treatment, whereby the amount of electrical energy required can be kept to a minimum.

A very preferred embodiment of the invention is that the first water cycle has a branching point connected via an additional water cycle to the diesel engine of the motor vehicle, whereby the additional water cycle is activated after exceeding the second temperature of the first water cycle at a temperature of -20a.

Conveniently, a second thermostat is provided at the junction, which is set to a second temperature value, in particular about 70 ° C, and produces this temperature value as the additional water circuit engages; 25 when crossing, so that also diesel fuel; is heated until this can be started via its own ignition and feed system. Similarly, in a particularly preferred embodiment of the invention, this diesel fuel supply system may also be connected to a heat exchange system of the first and a further 30:30 heat cycles to preheat this diesel fuel line. Optionally, this diesel fuel line may be further insulated with the water circulation components in an ambient manner with a foam.

• · • »· 5 1 1346 Γ

Conveniently, the first and the auxiliary water circulation are bypassed by the bypass line of the second thermostat, which may also include a throttling device. Therefore, the "reaction time" for the second thermostat is extended, which is advantageous especially in the case of a small amount of water in the first water cycle.

The auxiliary water circulation through the conduit branch may be in communication with the initial portion of the first water cycle to form a non-return valve for this conduit branch which opens in the direction of the diesel fuel tank. Thus, if the diesel engine of the vehicle is heated, the return flow of the auxiliary water circulation circuit may be connected directly to the diesel fuel tank when passing the heater, and then through the initial portion of the first water cycle.

The "reaction time" for the second thermostat is further increased so that in a particularly preferred embodiment of the invention, a vehicle heat exchanger, which can be provided with a vehicle fan, is fitted to the return stream of the first water cycle. The vehicle heat exchanger 20 may be combined with the interior of the vehicle, the battery compartment and / or other "pre-heating" equipment in the vehicle which is conveniently heated by the al-! stinky outdoor temperatures.

In another embodiment of the invention, there is provided a second: formed in the first water cycle a bypass line provided with a temperature limiter which, when the third temperature value is exceeded, bypasses: · 'the initial portion of the diesel fuel tank. The third temperature value is about 60 ° C. Through a temperature limiter, e.g., thermos-30, it is possible to limit the temperature in the "diesel fuel heating line" to prevent the formation of steam bubbles in the diesel fuel. Thus, the temperature limiter • closes the initial portion of the first water cycle from the temperature associated with the disadvantages of diesel fuel.

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Conveniently, the diesel fuel metering pump is disposed within the heater region to heat this pump along with the heater operation.

At higher lifting heights, e.g., at a lift height of greater than 5 mm, between the heater and the diesel fuel tank, such as the greater length of the diesel fuel line between the tank and the heater, particularly greater than 2,000 mm, it is convenient to

In particular, it is expedient to adapt the diesel fuel metering pump to heat contact with the first portion of the water cycle and the return stream 15 to the region of the diesel fuel intake, whereby the fuel pump, together with next to the diesel fuel tank.

Diesel fuel for the first water cycle • ·! for conducting the material line in or out of the hose or pipeline system, · · I, 'is formed at a passage point • 25 in a longitudinal section Y-shape • »| : other mouthpieces to allow fuel

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: a substantially "tangential" inlet or v 'outlet of the conduit from the hose or conduit system. Diesel fuel line outlet and gas line connection: * · *; 30 for first commissioning of the heater are in the immediate vicinity of the heater itself, so that parts of the die, *, fuel line not routed inside the plumbing system are preheated by the heater itself. The longitudinal part of the diesel fuel line after the gas line 35 connection to the heater 7 11346Γ is very short. If there is still diesel in this line, even after the heater has been switched off, it can still be started again with petrol.

The object underlying the invention is solved, in addition to a die-5 selective water heater, also in a diesel fuel air heater of the type claimed in claim 26, by means of a preheater which is an electric heater formed along the

Conveniently, the electric heater is located along the suction line of the diesel fuel line between the tank and the fuel pump and / or along the diesel fuel pressure line 15 between the fuel pump and the air heater.

The electric heating line may be an electric resistance-heating wire that is integrated inside or adjacent to the fuel line or freely placed inside the fuel line.

The electric heating line, in a preferred embodiment of the invention, may also be a heating wire self-regulating heating wire device having two parallel single wires provided with a bridging self-adjusting semiconductor element, whereby this device is either dense; "25 in contact with the fuel line or · · · · · · · · · · · · · · · ·: The fuel itself is inside the line. The advantage of this unit is that the overheating of the diesel fuel is * * * impossible, since the heating line is independently regulated depending on the temperature.

30 The heating wire device can also be made well, ·· *. simply by the meter, because the individual threads »» •> spring parallel and can be simply shortened to the desired length. It may also be very simple to provide only those diesel fuel lines with heat, 'j'; 35 wires actually needed for optimum * · 11346: δ color temperature control. This way, the need for electrical energy can be kept to a minimum.

The electric heater can thus (also) start the air heater in spite of the gelled 5 diesel lines. To "gelatinize" the fuel line, the suction and pressure lines, possibly also the inlet to the tank and the fuel pump, are electrically heated. The fuel lines can then also be relatively long. The air heater is particularly suited for use in a commercial vehicle (load compartment) 10 while driving.

The invention will now be described in more detail with reference to the accompanying drawings, in which: FIG. Fig. 3 shows a third embodiment of the preheating apparatus according to the invention according to Figs. 1 and 2; Figure 4 shows the interface D of Figure 1 private; 25, Figure 5 illustrates the diesel fuel intake of Figure 1 in more detail, v: Figure 6 shows the diesel fuel intake in an alternative embodiment and includes a description of diesel fuel injected in the vicinity of the diesel fuel tank. '·. of the metering pump, / # Fig. 7 shows a preheating '·' · apparatus of an air heater equipped with an electric heater '' in schematic perspective view and *> ·

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Figures 8-12 illustrate the arrangement of electric heating wires adjacent to the diesel fuel line in various embodiments.

The apparatus 1 illustrated in Fig. 1 for preheating liquid-5 diesel fuel for the heating device 4 comprises a diesel fuel tank 2 and a diesel fuel line 3 between the tank 2 and the heating device 4, wherein the diesel fuel line 3 is fitted with a diesel fuel delivery pump 10.

The heater 4 comprises a first water cycle 6 having an initial portion 16 between the heater 4 and the diesel fuel tank 2 and a return flow 17 between the diesel fuel tank 2 and the heater 4, wherein the first water cycle 6 more specifically described in Figure 5. In particular, the loop 7 comprises a vertical passage 23 which is joined by a U-shaped horizontal base 24 which becomes a vertical part of the return flow 17. Both vertical portions 23, 25 pass. are parallel to each other and are slightly »I ·; at a distance such that between the two vertical portions 23 and 25 extends in a parallel close relationship: • '25', the tank-side end of the diesel fuel line 3 is inserted into the container.

• t ·.; In one embodiment, the diesel fuel line 3 may be in contact with it, along the first portion 16, with a jacket contact where both lines are insulated.

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In another embodiment, the diesel fuel / t line 3 extends for the most part inside the front portion 16 * * * '·' ·. In this case, the above-mentioned end of the tank-side f * * diesel fuel line 3 leads to a longitudinal section of diesel fuel: j ': 35 at intake point A to junction D »» * »» 10

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4 through the mouthpiece 26, the diesel fuel line 3 can be accessed in the immediate vicinity of the diesel fuel tank 2, within the first portion 16 of the first water cycle 6, and there through the second portion 26 through the opening portion. , the latter mouthpiece 26 being disposed in the vicinity of the heating device 4.

The mouthpieces 26 have a straight tubular section 27 and 10 with an oblique opening 28 thereof made of metal or plastic, wherein the oblique section 28 serves exclusively to receive the diesel fuel line 3 and the straight tubular member 27 serves to receive preheated water along with the diesel fuel line 3. All ends of the aforementioned nozzles 27, 28 are provided with sealing tubes 29 or sealing tube 30 in a sealed manner, in particular with clips 34.

The return stream 17 of the first water cycle 6 has a branching point C connected to an additional water circuit 11, 20 having an initial portion 31 to the diesel engine 22 and a return flow 32 therefrom.

Branching site C comprises a second thermostat 12, '*,! which is set to about 70 ° C water operating temperature, whereby the thermostat is connected so that the return flow 17 of the first water cycle 6 at a water temperature below 70 ° C is directly connected via line branch 33 to the heater 1 4, while at a higher temperature the thermostat 12 v: connects the first water cycle return flow 17 to the initial portion 31 of the auxiliary water cycle 11, and the auxiliary water cycle return - *** ': 30 flow 32 is connected to the conduit 33.

The latter return flow 32 comprises a second bypass conduit 13 provided with a throttling device 14 for bypassing the thermostat so that a small amount of water in the small first water cycle 6 has sufficient "reaction time" for the thermostat 35a 12.

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The heating device 1 further comprises a separate gasoline supply device for the heating device 4 for initial commissioning of the device at a very low outdoor temperature. The separate gasoline supply device consists essentially of 5 petrol auxiliary reservoir 8, a gas line 10 between a gasoline auxiliary reservoir 8 and a heater-side diesel fuel line 3 connection B, whereby a gasoline metering pump 9 is fitted to the gas line 10.

Terminal B is located in the immediate vicinity of heater 4 so that only a small amount of conduit between diesel and heater 4 is disconnected after switching off heater 4.

The heater 4 is actually actuated by gasoline, whereby the petrol metering pump 9 delivers the gas to the heater 4. The petrol heater 4 heats the water in the first water cycle 6 so that the preheated water is initially fed 1620 to the diesel fuel tank 2 and

The preheating apparatus 1 may be used for the initial commissioning of a water heating apparatus * · * with gelled diesel; 25 for fuel use not only gasoline but also: alternatively electric heater; heating wire, or by adjusting the heating power itself, by a heating wire having two parallel single wires cross-linked through a self-regulating semiconductor, i.e.,; The heating wire then warms the diesel fuel line and / or intake point in the tank, or the fuel pump itself, at a point that is particularly undercooled by the ambient temperature during initial commissioning.

The electric heater is in principle constructed as: 35, as described in connection with the air heater of Figures 7-12, to which reference is made.

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1 1346 ° C

As soon as the "low" water circulation 6 has reached a sufficiently high temperature, e.g. 30-55 ° C and the diesel fuel line 3 passing through the initial portion 16 as well as the diesel fuel intake A in the diesel fuel tank 5 is also heated and thus paraffin free, via a separate thermostat or on the basis of a heater control signal that normally actuates the vehicle fan, to a diesel fuel metering pump 5 via a changeover relay. Through this, the gasoline lift pump 9 is connected and thus the diesel fuel supply apparatus of the heater 4 is started and in this way the heating operation of the heater 4 is continued without interruption.

If an operating temperature of about 70 ° C has been reached in the first water cycle 6, the auxiliary water circulation circuit 11 of the diesel engine 22 is turned on so that the engine 22 is also heated by the heater 4 until finally the diesel engine 22 can be started separately by this diesel supply system.

In the embodiment of Fig. 1, the diesel fuel metering pump 5 has an area '' '' of the heater 4! range. A prerequisite for this dependent adjustment of the diesel fuel metering pump 5 is that the maximum lift height 25 between the diesel fuel tank 2 and the heating device M * 4 does not exceed 4 750 mm, nor does the length of the diesel fuel line 3 exceed 2 000 mm. in connection with the lift height V 'and the longer diesel fuel line 3, the diesel fuel metering pump 5 is not located near the heater 30 but in the immediate vicinity of the diesel fuel inlet A according to Fig. 3, below the diesel fuel, * Ί 6 between the initial portion and the return flow 17 as exemplified in Figure 6. In connection with the diesel fuel metering pump 5 shown in Figure 6, the heat transfer •>> ·

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13 to 13 between the pump jacket and adjacent hoses of the first water cycle 6 is possible. In addition, the above area can be further insulated with the surrounding foam.

The exemplary embodiment of the preheating apparatus illustrated in Figure 2 corresponds substantially to that of Figure 1, however, in addition to the return flow 17 of the first water cycle 6, the vehicle heat exchanger 19 operates to increase the small first water cycle 6 10 by volume to provide a second thermostat. Further, the vehicle heat exchanger 19 provides the possibility of heating the vehicle interior, heating the battery and / or heating the vehicle's hydraulic system or the like.

In addition, the return flow 32 of the auxiliary water cycle 11 has a conduit branch 15 in communication with the opening 16 of the first water cycle 6 fitted with a non-return valve 18 which opens in the direction of the diesel fuel tank 2. At the operating temperature of the diesel engine 22, the return flow 32 of the auxiliary water circulation circuit 11 can be directly connected to the start portion 16 of the first water cycle 6 at the operating temperature of the diesel engine 22, i.e. when the heater 4 is bypassed. Diesel fuel engines; The market 22 then provides additional heating of the diesel fuel tank 2.

In the exemplary embodiment of the preheating apparatus V * 'illustrated in Fig. 3, there is a third in the return flow of the first water circulation before the vehicle heat exchanger 19; 30 a thermostat 21 or a temperature limiter that closes the first operating water when the temperature is above about 60 ° C. an initial portion of the water cycle 16 and feeds water to the second bypass; via a line 20 between the water outlet / heater 4 and the »» t thermostat 21 directly to the vehicle heat exchanger 35 19. That is, the diesel fuel line 3 in the initial portion 16! t •% * »> * f

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can warm up to 60 ° C, which prevents the presence of steam bubbles in diesel fuel.

Apparently, through the invention, the diesel-water heating device can also be actuated in a very simple manner by a very simple operation. The diesel water heater operates according to the evaporation principle and is in principle suitable for "bad" fuels even in extremely cold conditions.

Figure 7 schematically illustrates a perspective view 10 of an air heater 40 configured to heat the load compartment of a commercial vehicle while driving.

Without the heater 40, it is driven by diesel fuel and in this connection is provided with a diesel fuel j supply system equipped with a diesel fuel line 3, | 15 wherein the diesel fuel metering pump 5 is interposed. Dosing pump 5 divides fuel line 3 into suction line E and pressure line F.

In order to start the air heater at low outdoor temperature and in conjunction with the gelled diesel fuel line 20, various parts of the plant conducting and / or containing diesel fuel are heated by a preheating apparatus in the form of an electric heater.

The electric heating device 41 of FIG. * comprises western parts of the electric heating lines 42 along the suction line E and the pressure line F of the diesel fuel line 3 comprising an electric heating wire which is connected via an electrical connection 45 to the vehicle power source, particularly in the vehicle. vehicle battery with an on / off switch • V; 30 conveniently located in the area of the vehicle's dashboard and • which can be used by the driver.

* i 1 / t To prevent the diesel fuel from overheating, a thermostat may be installed which, when the engine is running automatically, only activates the heating wires 35 when the ambient temperature is below 0 ° C.

15 1 1546Γ

Also, the fuel pump and / or fuel filter can be electrically heated, whereby the heating wire is wound in close contact with these parts.

In addition, the heated sections or parts may be heat-insulated.

The electric resistance heating wire may be disposed on the outside of the diesel fuel line 3 in close contact in this respect, as shown in Figure 8, or integrated in or adjacent to Figure 9, or may also be freely mounted on the fuel line 310 as schematically illustrated.

In a particularly preferred electric heating variant, there is no electric resistance heating wire but a heating power self-regulating heating wire device having two parallel 15 individual wires 43, 44 which are crosslinked or limited by the self-regulating semiconductor element, the heating wire device being externally sheathed and insulated.

11, the heating wire device may be inserted, for example, as shown in Figure 11, into a heated fuel line portion along or along a portion of Figure 12.

With a self-regulating heating wire device, overheating of the diesel fuel is not possible since the heating power is independently regulated depending on the temperature. j 'The colder the outdoor temperature, the higher the warm-; 25 friends. As the temperature rises, the heating power decreases automatically; again. As a result, the vehicle network is loaded with ·, · 5 only the energy that is actually needed. System:: The system does not contain any susceptible components, such as thermostats or the like, nor does it contain any motion pictures. The construction is robust. Installation is simple, * * ·, especially with the construction of the so-called.

as a single piece, since the individual yarns run parallel and simply can also be shortened to the desired length of the heated part.

• t>> 11346 16

It should be further noted that, despite the formal reference made to the main claim, the protective features incorporated in the sub-claims must have the same independent protection.

Otherwise, all the inventive features included in the overall grounds of the application fall within the scope of the invention.

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Claims (29)

11346 '17 Apparatus (1) for preheating diesel fuel in heating units in movable units in a diesel fuel tank (2) and a diesel fuel supply system having a diesel fuel line (3) in a diesel fuel tank (2) and in a heating medium (5) , characterized in that the heating device (4) is connected to a first water cycle (6), the hose or pipe system having a loop (7) or a coil being led to a diesel fuel tank (2) in the immediate vicinity of the diesel fuel intake (A) and a diesel fuel line (3) except both ends 15) are provided for preheating by a hose and conduit along one region of the system. Preheating apparatus according to claim 1, characterized in that the diesel fuel line (3) is in contact with the outer jacket of the hose and pipeline system. A preheat device according to claim 2, characterized in that the diesel fuel line; (3) and the hose and pipe system have thermal insulation around the contact area. : · 25 A preheating device according to claim 1, characterized in that the diesel fuel line:: to (3) is arranged inside the hose and pipeline system. A precursor according to any one of claims 1-4. A heating apparatus, characterized in that the heating apparatus (4) is actuated through a separate gasoline-fed apparatus in advance of the first water cycle (6); up to the first water temperature set, and that a switching device is provided which, when the first water temperature is exceeded, activates the diesel fuel supply system and disables the gasoline supply system. Preheating apparatus according to claim 4 or 5, characterized in that the gasoline 5 feeding apparatus comprises a gasoline tank (8) which is connected via a gasoline line (10) with a gasoline metering pump (9) to the heating device (4), wherein the gas line (10) (B) opens in the immediate vicinity of the heating device (4) to the diesel fuel line 10 (3). The preheating apparatus according to any one of claims 1 to 4, characterized in that an electric heating device is formed, the electric heating line being arranged in the region of the diesel fuel intake (A) 15 and / or along at least a portion of the diesel fuel line (3). for preheating in the start-up phase of the heating device (4). Preheating apparatus according to claim 7, characterized in that the electric heating wire is an electric heating wire. A preheating apparatus according to claim 7, characterized in that the electric heating wire is a heating power self-regulating heating wire device, having a self-regulating semiconductor element; · Between its single thread. Preheating apparatus according to one of Claims 1 to 9, characterized in that the first water cycle (6) has a branching point (C) which is connected via a further water cycle (11) to a motor vehicle, * · *, diesel engine (22), · '(11) is activated after the second temperature value of the first water cycle (6) is exceeded. Pre-heating system 35 according to claim 10, characterized in that a second thermostat (12) is provided at the branching point 11346 Γ 19 ί! (C), which is adjusted to a second temperature value and performs a second switching on of the additional water circulation (11). when exceeding the temperature value. Pre-drainage apparatus according to claim 11, characterized in that the first and auxiliary water circulation (6, 11) includes a bypass line (13) which bypasses the second thermostat (12), the by-pass line (13) being a throttling device (14). Preheating apparatus according to one of Claims 10 to 12, characterized in that the auxiliary water circulation (11) communicates via the conduit branch (15) with the initial portion (16) of the first water cycle (6), wherein the conduit branch (15) is arranged in the diesel fuel tank (2). in the direction of the non-return valve (18) (Fig. 2). Preheating apparatus according to one of Claims 10 to 13, characterized in that a vehicle heat exchanger (19) is arranged in the return stream (17) of the first water cycle (6). The preheating apparatus according to any one of claims 10 to 14, characterized in that a second bypass line (20) is formed in the first water circulation (6) with a third thermostat (21) or a temperature limiter, which exceeding the value: '25 passes the initial portion (16) to the diesel fuel tank (2) (Figure 3). : j Preheating apparatus according to one of claims 1 to 15, characterized in that the diesel fuel metering pump (5) is arranged in the region of the heating device (4) (Figures 1 and 2). , ·. A preheating apparatus according to any one of claims 1 to 15, characterized in that the die. *: the fuel metering pump (5) is located in the region of the diesel fuel intake (A), whereby the diesel fuel,. The 35 material metering pump (5) is fitted to the heat transfer connection between the initial portion (16) and the return flow (17) between the first portion of the first water cycle (6) and the return flow (Figures 3 and 6). The preheating apparatus 5 according to claim 17, characterized in that the diesel fuel metering pump (5) together with the initial portion (16) and the return flow (17) are thermally insulated. Preheating apparatus according to one of Claims 10 to 18, characterized in that the diesel fuel line feeding the diesel combustion engine (22) is routed to the diesel fuel tank (2) in the heat transfer contact area along the first and additional water circulation (6, 11). The preheating apparatus 15 according to claim 19, characterized in that the diesel fuel line supplying the diesel engine (22) together with the longitudinal areas in contact with the first and auxiliary water circulation (6, 11) is thermally insulated. The preheating apparatus 20 according to any one of claims 4 to 20, characterized in that both ends of the diesel fuel line (3) are routed through the Y-shaped mouthpieces (26) to or from the inner part of the hose and pipe system · '' off (Figure 4). : * 25 A preheating apparatus according to any one of claims 5 to 21, characterized in that the water-f: temperature value is in the range of about 30 to 55 ° C. A preheating apparatus according to any one of claims 14 to 22, characterized in that the change-over switching device is a first thermostat with a variable temperature. said first water temperature, or changeover device • comprises a center position changeover relay which, via a "fan control" signal, switches the pump stroke signal from the gasoline metering pump (9) to the diesel metering unit; 35 pumps (5). 21, 11546C The preheating apparatus according to any one of claims 20 to 23, characterized in that the second temperature value is in the range of 70 ° C. The preheating apparatus 5 according to any one of claims 15 to 24, characterized in that the third temperature value is in the range of 60 ° C. A device for preheating diesel fuel for heating devices in mobile units in a diesel fuel tank (2) and / or in a diesel fuel supply system having a diesel fuel line (3) between the fuel tank (2) and the heating device an electric heater (40) fitted with an electric heater j 15 (41), the electric heater line (42) being disposed along at least a portion of the fuel line in or into its outer jacket region and / or formed in the diesel fuel inlet (A) region 2) (Figures 7-12). The preheating apparatus according to claim 26, characterized in that the electric heating line (42) is arranged along the '··' suction line (E) of the diesel fuel line (3) and / or the pressure of the diesel fuel line (3): line (F). ). : ·· 25 A preheat according to claim 26 or 27; Heating apparatus, characterized in that the electric heating wire (42) is an electric heating resistance wire (Figures 8, 9 and 10). A pre-heating apparatus according to claim 26 or T1, characterized in that the electric heating line (42) is a heating power self-adjusting heating / wire device having a self-adjusting semiconductor element and two parallel single wires (43, 44) (Figs. 11). and: · '· 12). * · 22 1 46-Pa tent kr av