EP3384150A1

EP3384150A1 - Fuel heating device having a heating device

Info

Publication number: EP3384150A1
Application number: EP16805371.8A
Authority: EP
Inventors: Tadeu Miguel Malago Amaral; Edson Valdomiro DE AZEVEDO JUNIOR
Original assignee: Mahle Metal Leve SA; Mahle International GmbH
Current assignee: Mahle Metal Leve SA; Mahle International GmbH
Priority date: 2015-11-30
Filing date: 2016-11-29
Publication date: 2018-10-10
Also published as: WO2017093269A1; US20180355828A1; BR102015030039A2

Abstract

The invention relates to a fuel heating device that can be used for cold starting motor vehicles, for example. The fuel heating device (5) comprises a fuel inlet (6) and at least one fuel outlet (7). The fuel heating device (5) further comprises at least one inner chamber (9), which is installed between the fuel inlet (6) and the fuel outlet (7) thereof. In said inner chamber (9), at least one heat exchanger (10) is installed, wherein the heat exchanger (10) has at least one first and one second heating element (11A, 11 B), which are inserted in an opening in the interior of the heat exchanger. In the opening of the heat exchanger, the heat exchanger (10) also comprises a first electrical conductor (12A) that is in electrical contact with the first heating element (11A), and a second electrical conductor (13) that is in electrical contact with the outer surface of the heat exchanger (10). Furthermore, the heat exchanger (10) has a circular cross-section.

Description

FUEL HEATING DEVICE WITH HEATING DEVICE

scope of application

The present invention relates to a heater for a fuel heater that can be used, for example, for the cold start, better driveability, reduced greenhouse gas emissions and other applications in motor vehicles. The invention also relates to a fuel injection device equipped with at least one such heater.

Background of the invention

Cold-start systems equipped with at least one such fuel heater are currently used in the automotive industry, particularly in vehicles that use low volatility fuels such as ethanol, methanol, or dual-fuel technology. Such fuels ignite comparatively poorly at low ambient temperatures, which makes it difficult in particular to start the respective internal combustion engine. Corresponding problems can also occur in particular with biofuels and with fuel mixtures of fossil fuel and biofuel. As is known to those skilled in the art, the proper combustion of the alcohol depends on the temperature. In the past, it was common for drivers to have difficulty running their alcohol-powered vehicles on colder days. The well-known technology of the "fuel tank", which is based on additional fuel injection to increase the fuel mix volatility, was a huge breakthrough and is today featured in most of Brazil's flexible-fuel vehicles, which accelerate the cold start on cooler days. although they still have several disadvantages Such as the high greenhouse gas emissions, high safety risks and leaks, and the disadvantage that the consumer must not forget to refuel the "gas tank" on cold days to allow the cold start of the vehicle.

Conscious of this reality, companies and researchers have thus developed electrical heating solutions so that the fuel is heated slightly above its flashpoint. This was to ensure that the engine is started even on cold days and that no additional injection of petrol or the well-known "fuel tank for cold starting" are necessary An example of the heating technology used is the heating element known as the "glow plug". The type of heater comes from diesel vehicle applications, has a metal rod shape, and is built into the fuel line, and heats the fuel that runs there before it is injected into the engine or engine inlet.

Despite the development of the "gas tank" this heating technology uses a high-temperature heater for rapid heating and thus increases the risk of fuel boiling (in this case, steam is injected instead of liquid fuel causes engine damage), the overheating, an internal pressure increase in components, leaks, and in extreme cases, even fire or melting of plastic parts Other fuel heating techniques for cold starting have been created, albeit in different geometrical constructions and positions than the "glow plug", for example incorporating some fuel heating techniques into the fuel nozzle. So far, all have a low heat exchange surface with the fuel and operate at high temperatures, although there are overheating and safety risks of the heater type "glow plug". In order to avoid the overheating risk of the fuel, fuel heaters operate in conjunction with a heater control unit, that is, with electronic "hardware" that monitors the heating of each heater and shuts it off in the event of overheating, in real time within a closed loop Due to the precise electronic "monitoring hardware", this technology is expensive, complex to implement and requires additional time to calibrate the vehicle and adjust and program the preheating times, and it should be noted that if an electronic component of the system is damaged or their connection fails after years of use, this can lead to disaster due to the high temperatures that can reach the heaters in contact with fuel.

In order to solve the drawbacks and inconveniences of this cold start system, the applicant has developed a new system in which the conventional heaters have been replaced by a "PTC thermistor" (thermistor with positive temperature coefficient) heating element together with a high efficiency heat exchanger. Thus, due to its positioning between the inlet and outlet of the heater, the fuel comes into contact with the heat exchanger, which supplies the received heat from the inside by means of the "thermistor". This system heats the fuel rapidly, relying on the PTC thermistor with a low surface temperature and controlling itself by doping semiconductors, which system prevents the fuel from exceeding a certain temperature in the doping and in the Manufacturing method of the respective PTC element is selected, and eliminates the previously incurred inconvenience. The temperature at which such a PTC element is designed and at which the PTC element decays, so that maximum reached this temperature can also be referred to as Abregeltemperatur. It should be noted that although there are other PTC type heaters, only such PTC technologies, without the use of high efficiency heat exchangers, require a PTC with a high surface temperature. In addition, there is still the need for electronic "hardware" for temperature control.

Further information on the description of the heating system of the type PTC with a highly efficient heat exchanger can be found in the documents DE 10 201 1 086 201 and DE 10 2012 220 429, whose descriptions have been listed here as a reference material. Although this new cold start system has brought great benefits, there are still some issues that need to be addressed in the prior art.

As can be seen from the above-mentioned documents DE 10 201 1 086 201 and DE 10 2012 220 429, the heat exchangers described and illustrated therein have a format whose cross-section is substantially oblong. This format is labor-intensive due to the usually used processing processes. In addition, the elongated format does not allow even heat distribution. It follows that such a format is inefficient and that a better solution must be found in the current state of the art.

Description of the invention

Therefore, it is the object of the invention to provide a fuel heater that allows for easier heat exchange. The fuel heater is generally intended to allow efficient heating of the respective fuel. In particular, the Fuel heater can allow evaporation of the respective Krafstoffs. The latter applies in particular to biofuels.

Another object of the present invention is to provide a fuel heater that allows uniform heating of the fuel that comes in contact with outer walls of the fuel heater.

[01 1] The objects of this invention are achieved by the fuel heater comprising: a fuel inlet and at least one fuel outlet, the heater having at least one interior space disposed between the fuel inlet and fuel outlet, wherein at least one heat exchanger is disposed in the interior space and wherein the heat exchanger has at least a first and a second heating element, which are inserted into an opening in the interior of the heat exchanger; the heat exchanger further comprises a first electrical conductor in its opening in electrical contact with the first heating element and a second electrical conductor in electrical contact with the outer surface of the heat exchanger. In addition, the heat exchanger has a round, in particular circular, cross-section.

[012] Optionally, this fuel heater has the following additional features and / or properties with optional use:

- The first electrical conductor is a conductive spring comprising a contact portion which makes contact with the heating elements, and an electrical contact end which makes contact with an electrical circuit of a motor vehicle, when the contact portion and the contact end are fully installed; and or

- The contact portion of the first electrical conductor has a curved format; and or - The contact portion consists of two curved, opposite side parts, which are at a distance from each other; and or

- The first heating element is located along the one side part of the contact portion of the first electrical conductor and the second heating element is located along the other side part of the contact portion of the first electrical conductor; and or

- The first and second heating element are on both side parts of the contact portion of the first electrical conductor by means of an electrically non-conductive, that is electrically insulating holder, e.g. polymeric material, said holder having front and rear support walls for securing the heating elements such that they are easy to remove, and central receptacles for receiving and positioning each side portion of the contact portion of the first electrical conductor; and or

the contact portion of the first electrical conductor, the heating elements and the support radially form a "sandwich" structure, and / or

the fuel heater additionally comprises at least one thermally conductive foil around the "sandwich" structure, and / or

- The heating elements are thermistors, in particular PTC thermistors; and or

the heat exchanger comprises a grooved portion having a plurality of grooves on its outer surface; and or

- At least one radial recess may be located on at least a portion of the outer surface of the heat exchanger, which extends in particular axially; and or

- The holder has a cylindrical shape, with their recordings are arranged in a circular arc and concentric; and or

- The first and second heating element and at least one optionally existing thermally conductive foil have a, in particular circular arc-shaped, arched format; and or - The fuel heater comprises at least one deflector disposed in the fuel inlet, the function of which is to redirect the incoming fuel flow in the lower region of the interior of the heater; and or

- The deflector can engage radially in the above-mentioned recess; and or

the heat exchanger comprises an upper and continuous sealing portion along the ribbed portion, the function of said sealing portion being to receive at least one sealing element; and or

- The interior consists of a container and a fastening and sealing nozzle, wherein the container configured for receiving the ribbed portion of the heat exchanger and the fastening and sealing nozzle for receiving the sealing portion of the heat exchanger is set; and or

the sealing element is a sealing ring of the "O-ring" type, and / or

- Over the sealing portion of the heat exchanger is a protective cover which holds the first, the second and an optionally provided third electrical conductor; and or

- Over the protective cover is a plastic cover, this plastic cover can be molded onto the protective cover; and or

- The fuel heater also includes a mounting clamp, which is inserted into the through holes of the mounting nozzle and placed around the plastic cover portion, which is located inside the mounting and sealing nozzle. The said clamp also still includes free, expanded, ie, away from each other or outwardly facing ends; and or

the fuel inlet of the heater may be fluidly connected to the fuel outlet of a fuel line and the Fuel outlet of the heater can be directly connected to at least one fuel injector; and or

the fuel heater can be fully installed in the fuel line; and or

- The first heating element and the second heating element have the same behavior and the same Abregeltemperatur; and or

- The first heating element and the second heating element have different behaviors and Abregeltemperaturen; and or

- In the opening, a third electrical conductor is present, the second electrical conductor is in electrical contact with the second heating element and has a curved format; and or

the third electrical conductor is a conductive spring comprising a contact portion which makes contact with the heating elements and an electrical contact end which makes contact with an electric circuit of a motor vehicle when the contact portion and the contact end are completely installed; and or

- The first heating element is located along a side part of the contact portion of the first electrical conductor and the second heating element is located along a side part of the contact portion of the third electrical conductor; and or

the first and second heating elements are connected to each side portion of the contact portion of the first and third electrical conductors by means of an electrically insulated support, e.g. polymeric material, said holder having a front and rear support wall for positioning and / or fixing the heating elements such that they are easy to remove, and in particular concentric seats for receiving the first and third electrical conductors and to position; and or

- The contact portion of the first and third electrical conductor, the heating elements and the holder form radially seen a "sandwich" structure. Brief description of the figures

These and other objects, the technical and functional improvements, and the advantages of the fuel heating system which is the subject of this invention, will be apparent to those skilled in the art from the accompanying schematic drawings which illustrate a preferred, non-limiting embodiment of this invention.

Fig. 1 shows a view of the fuel heater of the present invention connected to a fuel line and to fuel injectors according to a first mounting option;

Fig. 2 is a view of the fuel heater of the present invention connected to a fuel pipe;

Fig. 3 is a view of the fuel heater of the present invention connected to a fuel line and to fuel injectors according to a second mounting option;

Fig. 4A is a detail view and a sectional view of the fuel heater of the present invention according to a first specific embodiment;

Fig. 4B is a sectional view of the fuel heater of the present invention according to a first specific embodiment;

Fig. 5 is an exploded view of the components of the heater of the present invention according to a first specific embodiment; Fig. 6 is a view of the heat exchanger of the fuel heater according to a first embodiment of the invention;

Fig. 7 is a view of the electric conductor of the fuel heater according to a first embodiment of the present invention;

Fig. 8 is a view of the holder of the fuel heater according to a first embodiment of the present invention;

9 shows a side view of the portion of the fuel heater according to a first embodiment of the present invention, wherein the heater is connected to a fuel line and a fuel injector in a second mounting facility (as also shown in FIG. 3);

Fig. 10 is a side view of the portion of the fuel heater of the present invention according to a first embodiment, wherein the heater is connected to a fuel pipe;

Fig. 1 shows a side view of the portion of the fuel heater of the present invention according to a first embodiment, wherein the heater is connected to a fuel line and the internal components of the heater (except for a deflector) have been removed for better visibility;

Fig. 12 is a sectional view of the fuel heater according to a first embodiment of the invention, wherein the illustrated heater comprises a deflector; Fig. 13 shows a side view of the portion of the fuel heater according to a first embodiment of the invention, wherein the heater is connected to an injector and a fuel line, according to a first mounting option (as shown in Figures 1 and 2);

Fig. 14 shows a side view of the portion of the fuel heater of the present invention according to a first embodiment of the invention, wherein the heater is connected to a fuel line. In this figure, the first mounting option is used (as shown in Figures 1, 2 and 13);

Fig. 15 shows a side view of the portion of the fuel heater according to a first embodiment of the present invention, wherein the heater is connected to a fuel line and the internal components of the heater (with the exception of the deflector) have been removed for better visibility. In this figure also the first mounting option is used (as shown in Figures 1, 2, 13 and 14);

Fig. 16 is a sectional view of the fuel heater according to a first embodiment of the present invention, wherein the heater is connected to a fuel line. In this figure also the first mounting option is used (as shown in Figures 1, 2, 13, 14 and 15);

Fig. 17 is a plan view of the heater without the components inserted; Fig. 18 is a detail view and a sectional view of the fuel heater of the present invention according to a second specific embodiment;

Fig. 19 is a sectional view of the fuel heater of the present invention according to a second specific embodiment; and

Fig. 20 is an exploded view of the components of the heater of the present invention according to a second specific embodiment.

Embodiment of the invention

The invention will now be described with reference to the accompanying drawings. In the figures and in the following description, like parts are identified by like reference numerals. The figures are not necessarily to scale, that is certain features of the invention may be illustrated in an exaggerated or diagrammatic manner. Also, the details of the conventional elements may not be so depicted as to illustrate this description with greater clarity and clarity. The terms "axial" and "radial" and "circumferential direction" refer in this context to a longitudinal central axis of the respective heating device, wherein the axial direction is parallel to the longitudinal central axis, the radial direction is perpendicular to the axial direction and the circumferential direction rotates about the longitudinal central axis.

The heater 5 of the present invention may be connected to a fuel pipe 2, as shown in FIGS. 1, 2 and 3. From Figures 1, 2, 3, 1 1, 12, 15 and 16 it is apparent that the Fuel line 2 is provided with a fuel inlet 3 and with a fuel outlet not specified here. As a rule, the fuel line 2 has a plurality of fuel outlets for a plurality of heating devices 5. Each heater 5 also has a fuel inlet 6 and a fuel outlet 7. It is also worth noting that the fuel inlet 6 of the heater 5 is fluidly connected to the fuel outlet of the fuel line 2. Consequently, the fuel outlet of the fuel pipe 2 can be reacted so as to coincide with the fuel inlet 6 of the heater 5. In particular, the heating device 5 with its fuel inlet 6 can be inserted directly into the associated fuel outlet of the fuel line 2. This can be seen most clearly in Figures 1 1, 12, 15 and 16. In addition, the fuel outlet 7 of the heating device 5 can be connected to a fuel injector 8, as shown in FIGS. 9 and 13. In particular, the respective fuel injector 8 can be inserted directly into the associated fuel outlet 7.

[037] FIGS. 11, 12, 15 and 16 show a heating device 5 which has an interior 9 which is arranged between its inlet 6 and its fuel outlet 7.

This construction shows that the fuel coming out of the vehicle tank passes through the conduit 2, passes through the interior 9 of the heater 5 and is finally injected into the engine by means of one or more injectors 8.

In order to properly heat the fuel, this invention has a heat exchanger 10 installed in the interior 9 of the heater 5. As illustrated in FIGS. 6 and 20, the heat exchanger 10 has a ribbed portion 20 having a plurality of ribs on its outer side surface or outer surface, as well as one With respect to these two portions 20 and 24 of the heat exchanger 10, the inner space 9 is adapted to receive these components or portions 20, 24 in its interior while being in contact therewith Purpose with a container 25 and a mounting and sealing nozzle 26 is provided. As illustrated in FIGS. 9, 10, 13 and 14, the container 25 is configured to receive or condition the corrugated portion 20 while the three attachment and sealing nozzles 26 are configured to receive the sealing portion 24 of the heat exchanger 10. According to a first particular embodiment of the present invention, the heat exchanger 10 has a substantially circular cross section, as illustrated in Figure 6, having a recess 21 on the outer surface of the corrugated portion 20 on at least part of its outer surface. Furthermore, the heat exchanger 10 is preferably made of metallic material. However, other heat and electricity conducting materials are not excluded which are as effective or better than metals and which may possibly be used.

The heat exchanger 10 is also equipped with at least two heating elements 1 1A and 1 1 B, which are inserted into an opening formed in the interior of the heat exchanger 10, as shown in Figures 4A, 4B, 18 and 19 can be seen , These heating elements 1 1A and 1 1 B are preferably a thermistor of the type PTC (positive temperature coefficient). In a particular embodiment of the present invention, the heating elements 1 1A and 1 1 B may have the same behavior and the same heating temperature or different behaviors and / or heating temperatures. The heating temperature is the control temperature of the PTC element, ie the temperature to which heats the PTC element and from the PTC element no electrical More power consumes. In the same opening of the heat exchanger 10, where the heating elements 1 1 A and 1 1 B are located, there is at least a first electrical conductor 12A.

In a particular embodiment of the present invention, the heater 5 has a first curved electrical conductor 12A, as illustrated in FIG. 5, for example. In a further embodiment of the present invention, the heating device 5 of this invention still has a third electrical conductor 12B, which also has a curved format, as illustrated in Figures 18 to 20. In the following embodiments, the electrical conductor 12A and / or 12B are respectively in electrical contact with the first and second heating elements 11A and 11B. In the embodiments illustrated in the figures, the first electrical conductor 12A and the third electrical conductor 12B, a conductive spring, which is shown for example in Figures 5, 7 and 20. This spring consists of a contact portion 14 which abfast the heating elements 1 1 A and 1 1 B, and from an electrical contact end 15 which is completely installed in the contact portion 14. In the embodiment shown in Figure 5, the contact portion 14 consists of two curved, opposite side parts (or portions), which are at a distance from each other. In the embodiment shown in Figs. 17 to 20, the contact portion 14 of the respective electrical conductors 12A and 12B consists of a single side portion (or a single portion).

The heat exchanger 10 further includes a second electrical conductor 13 in electrical contact with its outer surface. This second electrical conductor 13 may be secured to the heat exchanger 10 by any means, such as welds or screws. In the embodiment shown in Figure 5, the second electrical conductor 13 to the heat exchanger 10 by means of a Screwed down screw 22. In addition, the electrical conductors 12A, 13 and 12B are electrically connected to a circuit as illustrated in the embodiment shown in Figures 4A, 4B and 5 and the embodiment illustrated in Figures 18 to 20. In the case of the first conductor 12A and the third conductor 12B, contact is made through the end 15 of each conductor. Preferably, the circuit in question is an already existing circuit in the engine control of the vehicle. Furthermore, it can be seen from FIGS. 5, 7 and 20 that the contact section 14 and the electrical contact end 15 have been produced from a single part.

In the embodiment illustrated in FIGS. 18 to 20, the first heating element 11A and the second heating element 11B are located along a side portion of a contact portion 14 of the first electrical conductor 12A and the third electrical conductor 12B. In the embodiment shown in Figure 5, the first heating element 1 1A is located along the one side portion of the contact portion 14 of the first electrical conductor 12A and the second heating element 11B is along the other side portion of the contact portion 14 of the first electrical conductor 12A. In each case, a radially "sandwich" structure is formed in each case.

In an embodiment of the present invention shown, it should be noted that the heating elements 1 1A and 1 1B have a substantially curved shape, as can be seen for example from FIG. This curvature can be circular in particular.

To hold the sandwich structure together, insert it properly, and install it easily, a bracket 17 is still provided, as illustrated in Figures 5, 8, and 20. More specifically, the two heating elements 1 1A and 1 1 B are provided by means of said holder 17, which is made of polymer material, by the way Bracket 17 further includes front and rear support portions 18 for securing and positioning the heating elements 11A and 11B so that they are easy to remove. In addition, the holder 17 has seats 19 arranged concentrically with respect to the longitudinal center axis in order to receive and position the first electrical conductor 12A and the third electrical conductor 12B (in the case of the embodiment illustrated in FIGS. 18 to 20). The bracket 17 may have various shapes. In FIGS. 5 and 8, the holder 17 has, for example, flat support regions 18 and concentric receptacles 19 on a surface which, like the heat exchanger 10, may be formed, eg may have an elongated or elliptical shape, if this corresponds to the cross section of the heat exchanger 10. In a further embodiment of the invention shown in Figure 20, the holder 17 has a circular cross-section and the concentric receptacles 19 are circular arc-shaped.

In a particular embodiment of the present invention and with the aim of improving the heat conduction of the heating elements 1 1 A and 1 1 B, which flows through the heat exchanger 10, one or more thermally conductive sheets 16 may alternatively be provided. In the particular embodiments of the present invention illustrated in FIGS. 5 and 20, the thermally conductive sheets 16 are placed around the "sandwich" structure composed of the heating elements 11A and 11B, the contact portions 14 of the first electrical conductor 12A (also from the third conductor 12B in the case of the embodiment of Figures 18 to 20) and the support 17. In Figure 5, the film 16 has such a shape as to allow the support 17 with the first conductor 12A and the built-in In Figure 5, the foil 16 also wraps the support 17 with the first and third electrical conductors 12A and 12B and with the built-in elements 1AA and 11B. In Figures 5 and 20 it should be noted that the heat-conductive foils 16 a arched shape so that they can wrap the elements that form the equally curved "sandwich" structure.

[047] With regard to the sealing of the heater 5 of the present invention, it is first of all worth mentioning that the seal portion 24 of the heat exchanger 10 is formed so as to be able to accommodate at least one seal member 27. In the embodiment shown in the figures, the sealing element 27 in question is an "O-ring" type sealing ring incorporated in the sealing portion 27 of the heat exchanger 10 and shown in Figs. 4A, 4B, 5, 9, 10, 13, 14 18, 19 and 20. Referring now to Figures 5 and 20, over the sealing portion 24 of the heat exchanger 10 is a protective cover 28 which holds the electrical conductors 12A, 12B and 13 in any embodiment of the present invention More specifically, the protective cover 28 is fastened over all the electrical conductors 12A, 12B and 13, the attachment being able to take place, for example, by means of bores on the protective cover 28. Over the protective cover

28 is also still a plastic cover 29, with this cover

29 may be molded onto the protective cover 28. The final form of this gating can be illustrated, for example, in the embodiments illustrated in FIGS. 4A, 4B, 9, 13, 18 and 19.

The attachment of the components in the interior of the interior 9 is now illustrated in Figures 5, 9 to 17 and 20. As can be noted, the heater 5 is supplied with a bow-shaped attachment clip 30 for each heater 5. This clamp 30 is inserted into passage openings 31 which are formed on the fastening and sealing connection 26. When inserted into the openings 31, the clamp 30 lies around the plastic cover portion 29, which is located inside the mounting and sealing nozzle 26. Said terminal 30 additionally has free ends 32, which secure attachment enable. For this purpose, the ends 32 can be bent outwards, ie away from one another, so that they can interact with an opening edge of the respective opening 31.

Apart from the components already mentioned, in a particular embodiment of the present invention, the heating device 5 may optionally have a deflector 23, as shown in FIGS. 9 to 12. This deflector 23 is attached to the fuel inlet 6 (in the area shown in FIG. 17) and serves to deflect the incoming fuel flow into the lower region of the interior 9 of the heating device 5. In particular, the deflector 23 effects the most uniform possible distribution of the incoming fuel to the entire Axial height of the ribbed portion 20. By this deflector 23 a greater contact time of the fuel is forced with the heat exchanger 10, before it is injected. The deflector 23 expediently engages in the aforementioned recess 21, which is formed on the outside of the heat exchanger 10.

In a particular embodiment of the present invention, the heater 5 and the conduit 2 are completely installed. In other words, these two components can form a single part. In a particular embodiment of the present invention, the heater 5 and the conduit 2 are made by molding and injecting polymer materials. After assembly, inside the interior 9, the heat exchanger 10 (and all other components located in its interior), the deflector 23 (optional), the sealing element 27 and the protective cover 28 onto which the plastic cover 29 is subsequently injected, appropriate.

[051] With regard to the mounting option, it can be seen from FIGS. 1 to 3 and 9 to 16 that there are several variants. In a certain Embodiment of the present invention, the fuel inlet 6 and the fuel outlet 7 of the heater 5 may be arranged to form an angle (with respect to each other) varying, for example, between 0 ° and 90 °. Thus, for example, Figures 9 to 12 show that this angle is substantially 0 °, so that the fuel inlet 6 and fuel outlet 7 are diametrically opposed. In contrast, in FIGS. 13 to 16, this angle is less than 90 °, and in FIG. 4 the angle is substantially 90 °. Of course, the angle between the fuel inlet 6 and the fuel outlet 7 of the heater 5 may vary depending on the engine configuration, the available space and the application, etc., so that the figures represent only one example of the various possible arrangements.

[052] As will be appreciated, the heater 5 of the present invention is fully installed, thus being a single part requiring no "clamps" and sealing rings to secure the heaters 5 and the fuel line 2. In FIG In connection with this feature, the strong sealing and fixing of the parts, which, thanks to the injection of the plastic cover 29 and the function of the protective cover 28, fasten all the components, including the terminal 30, which aids in fixing, should be emphasized.

[053] Furthermore, it can be seen from the embodiment illustrated in FIGS. 18 to 20 that the fact that the heater 5 has at least three electrical conductors 12A, 12B and 13 provides a number of advantages. Among these advantages, the following should be mentioned: two heating elements 11A and 11B can be activated in one go, thus increasing the heat given off to the fuel, or it can be selected if only one heating element is used. If the vehicle requires a rapid heating of the fuel, thus the first and the second heating element 1 1 A and 1 1 B are activated. If the vehicle requires only slightly heated fuel, only one of the heating elements 1 1 A or 1 1 B is activated.

[054] The control over the heat supplied to the fuel is increased with the possibility that the heating elements 1 1A and 1 1 B may have different behaviors and heating temperatures. The ability to activate one or the other heating element, or even both at the same time, thereby provides flexibility to the vehicle's cold start system, thereby increasing the ability to deliver a better product to the consumer.

[055] With these electric conductors 12A, 12B and 13, the engine control of the vehicle can be adjusted to supply the heating elements 1 1A, 1 1 B at temporally different intervals. For example, a short period for preheating the fuel may be set so that both heaters 1 1A and 1 1 B are simultaneously activated in the first few seconds before starting the vehicle. As a result, the driver does not need to wait long to drive his vehicle since the fuel is already at the ideal temperature when the starting system is activated.

[056] Another advantage and control of the present invention relates to the fact that the motor control can be adjusted with on-off control strategies or even uses pulse width modulation (PWM).

[057] From these characteristics, it can be seen that the fuel heater 5 provides a versatile solution that offers numerous opportunities to control the heat supplied to the fuel. Due to the fact that the invention different types of control and strategies, the present invention can provide means for the fuel to always have the ideal temperature for cold start and vehicle use.

The fact that the cross section of the heat exchanger 10 has a round shape, preferably a substantially circular shape, increases the contact area between the heating elements 1 1A and 1 1 B and the internal portion of the heat exchanger 10. Further, a part having a make round cross-section easier and also facilitates the execution of the grooves or ribs. The ease of obtaining this part reduces process errors and optimizes manufacturing costs. In addition, the heating elements 1 1A and 1 1 B can be arranged in positions with a greater distance from each other with respect to the heat exchanger 10 with an elongated shape. Thus, the heat generated by the heating elements 1 1A and 1 1 B is almost entirely directed to the heat exchanger 10.

[059] Thus, the circular cross-section results in a significant increase in heating power and a drastic reduction in manufacturing cost, and with such success, solves the problems of the prior art.

Thus, as known to those skilled in the art, numerous modifications and variations of the invention are possible in light of the above-mentioned teachings without departing from the scope of the invention, which is defined by the appended claims.

Claims

Fuel heater (5) characterized by comprising:

a fuel inlet (6) and at least one fuel outlet (7); wherein the heater (5) has at least one interior space (9) disposed between the fuel inlet (6) and the fuel outlet (7);

in said interior (9) at least one heat exchanger (10) is arranged, wherein the heat exchanger (10) has at least a first and a second heating element (1 1A, 1 1 B), which in a

Opening are inserted into an interior of the heat exchanger (10); the heat exchanger (10) also comprises at least:

a first electrical conductor (12A) in its interior which is in electrical contact with the first heating element (11A); and a second electrical conductor (13) in electrical contact with the outer surface of the heat exchanger (10),

wherein the heat exchanger (10) also has a round, in particular circular, cross-section.

A heating device according to claim 1, characterized in that the first electrical conductor (12A) is a conductive spring comprising:

a contact portion (14) which serves to make contact with the heating elements (1 1A, 1 1 B); and

an electrical contact end (15) that makes contact with an electrical circuit of a motor vehicle.

3. A heating device according to claim 1, characterized in that the contact portion (14) of the first electrical conductor (12A) has a curved shape.

4. Heating device according to claim 3, characterized in that the contact portion (14) has two curved, opposite side parts, which are at a distance from each other.

5. Heating device according to one of claims 1 to 4, characterized in that the first heating element (1 1 A) along one side part of the contact portion (14) of the first electrical conductor (12A) and the second heating element (1 1 B) extends along the other side portion of the contact portion (14) of the first electrical conductor (12A).

6. Heating device according to claim 4 or 5, characterized in that the first and the second heating element (1 1 A, 1 1 B) on the respective side part of the contact portion (14) of the first electrical conductor (12A) by means of a holder (17 ), said support (17) having front and rear support walls (18) for positioning the heating elements (11A, 11B), and receptacles (19) around each side portion of the contact section (14). of the first electrical conductor (12A).

7. Heating device according to claim 6, characterized in that the contact portion (14) of the first electrical conductor (12A), the heating elements (1 1A, 1 1 B) and the holder (17) form a "sandwich" structure.

8. Heating device according to claim 7, characterized in that it also has at least one heat-conducting film (16) around the "sandwich" structure.

9. Heating device according to one of claims 1 to 8, characterized in that the heating elements (1 1A, 1 1 B) are thermistors.

10. A heating device according to any one of claims 1 to 9, characterized in that the heat exchanger (10) comprises: a ribbed portion (20) having a plurality of ribs on its outer surface for contacting with the fuel.

1 1. A heater according to claim 10, characterized in that the heat exchanger (10) comprises: at least one recess (21) on the outer surface of the ribbed portion (20).

12. Heating device according to claim 1 1, characterized in that the at least one recess (21) is located on at least part of the outer surface of the heat exchanger (10).

13. A heating device according to claim 6 or claim 6 and one of claims 7 to 12, characterized in that the holder (17) has a cylindrical shape, wherein their receptacles (19) are arranged in a circular arc and concentric.

14. A heating device according to claim 8 or claim 8 and one of claims 9 to 13, characterized in that the first and second heating element (1 1A, 1 1 B) and at least one heat-conducting film (16) have a curved shape.

15. A heating device according to one of claims 1 to 14, characterized in that it comprises at least one in the fuel inlet (6) embedded deflector (23) whose function is the incoming fuel flow in the lower region of the interior (9) redirect the heater (5).

16. Heating device according to claims 1 1 or 12 and 15, characterized in that the deflector (23) engages in the recess (21).

17. A heating device according to claim 10 or claim 10 and one of claims 1 1 to 16, characterized in that the heat exchanger (10) has an upper and continuous sealing portion (24) along the ribbed portion (20), wherein the function said sealing portion (24) is to receive at least one sealing element (27).

18. A heating device according to claim 17, characterized in that the interior (9) has a container (25) and a fastening and sealing nozzle (26), wherein the container (25) for receiving the ribbed portion (20) of the heat exchanger ( 10) is configured, while the fastening and sealing nozzle (26) for receiving the sealing portion (24) of the heat exchanger is configured.

19. Heating according to claim 18, characterized in that the sealing element (27) is a sealing ring of the type "O-ring".

20. A heating device according to claim 18 or 19, characterized in that above the sealing portion (24) of the heat exchanger (10) is a protective cover (28), the first (12A), the second (13) and the third ( 12B) holds the electrical conductor.

21. Heating device according to claim 20, characterized in that above the protective cover (28) is a plastic cover (29), which may in particular be injection-molded onto the protective cover (28).

22. A heating device according to any one of claims 18 to 21, characterized in that it further comprises a fastening clip (30) which is inserted into through holes (31) of the Befestigungsund Dichtungsstutzens (26) and the plastic cover portion (29) arranged encompassing is located inside the mounting and sealing nozzle (26).

23. Heating device according to one of claims 1 to 22, characterized in that the fuel inlet (6) of the heating device (5) fluidly with the fuel outlet of a fuel line (2) directly connected, in particular plugged, and that the fuel outlet (7 ) of the heating device (5) with at least one fuel injector (8) directly connected, in particular plugged, can be.

24. Heating device according to claim 23, characterized in that it is completely installed in the fuel line (2).

25. Heating device according to claim 7 or claim 7 and one of claims 8 to 24, characterized in that the first heating element (1 1A) and the second heating element (1 1 B) have the same behavior and / or the same Abregeltemperatur ,

26. A heating device according to claim 9 or any one of claims 10 to 24, characterized in that the first heating element (1 1A) and the second heating element (1 1 B) have different behaviors and / or Abregeltemperaturen.

27. A heating device according to one of claims 1 to 26, characterized in that in the opening of the heat exchanger (10), a third electrical conductor (12 B) is present, said third electrical conductor (12 B) in electrical contact with the second Heating element (1 1 B) is and has a curved format.

A heating device according to claim 27, characterized in that the third electrical conductor (12B) is a conductive spring comprising: a curved contact section (14) which makes contact with the heating elements (1 1A, 1 1 B ) produces; and an electrical contact end (15) that makes contact with an electrical circuit of a motor vehicle.

29. A heating device according to claims 1 and 2, characterized in that the first heating element (1 1A) along the one side part of the contact portion (14) of the first electrical conductor (12A) and the second heating element (1 1 B) along the other Side part of the contact portion (14) of the third electrical conductor (12B) extends.

30. A heating device according to claim 29, characterized in that the first and the second heating element (1 1 A, 1 1 B) on the respective side part of the contact portion (14) of the first and third electrical conductor (12A, 12B) by means of a holder (17), said holder (17) having front and rear support walls (18) for positioning the heating elements (11A, 11B) and seats (19) around the first and third ones electrical conductor (12A, 12B) to position.

31. Heating device according to Claims 29 and 30, characterized in that the contact sections (14) of the first and third electrical conductors (12A, 12B), the heating elements (1 1A, 11 B) and the holder (17) have a " Sandwich "structure form.

32. Fuel injection device for an internal combustion engine, which has at least one cylinder,

with at least one fuel injector (8) for injecting fuel into the cylinder,

with at least one fuel line (2) for supplying the fuel to the respective fuel! injector (8),

with at least one heating device (5) for demand-dependent heating of the fuel, which is arranged fluidically between the fuel line (2) and the respective fuel injector (8).

33. Fuel injection device according to claim 32, characterized

in that the heating device is designed according to claim 26, that a control device is provided, which is designed such that it depends on at least one control parameter, such as Fuel temperature in the fuel line or ambient temperature or fuel type or

Fuel composition, optionally only the first heating element (1 1A) or only the second heating element (1 1 B) or both heating elements (1 1 A, 1 1 B) for heating the fuel drives.