A FLOW CONDUIT AND MEANS FOR ENLARGING THE SURFACE THEREOF TO PROVIDE COOLING, AND A FUEL PIPE, AND A METHOD FOR THE MANUFACTURE THEREOF

Abstract: The present invention features a profile for cooling fuel or the like fluid comprising a tubular element with at least one flow conduit and surface-enlarging means for cooling the fluid in the flow conduit, wherein the cooling means are configured as one or more cooling blades that extend diametrically from the centrally arranged tubular element, said cooling blades featuring a bendable base section and an outer section provided with cooling fins. The invention also relates to a fuel pipe with one or more angulations for establishing flow communication between a tank and a motor installation in a vehicle, and a method for the manufacture thereof. Hereby an uncomplicated solution is obtained that exhibits an extremely satisfactory cooling of the fuel in a fuel pipe, such as the return flow of a tank installation in a diesel vehicle, no dirt and other matter being deposited thereon which may otherwise have an insulating effect, and it is thus also possible that the fuel pipe can be configured in one piece whereby soldered joints and other mechanical joints are avoided which minimises the risk of leaks.

Description: A flow conduit and means for enlarging the surface thereof to provide cooling, and a fuel pipe, and a method for the manufacture thereof The present invention relates to a flow conduit and surface-enlarging means for cooling the fluid contained in said flow conduit. The invention further relates to a fuel pipe with one or more angulations for establishing flow communication between a tank and a motor installa- tion in a vehicle, and a method for the manufacture thereof. The fuel system in a vehicle serves to supply fuel to the motor from the tank installation of that vehicle. The fuel is pumped into an advance conduit leading to the motor. The fuel which is not consumed in the motor is extremely hot and is pumped back into the tank via a return conduit. WO 94/23257 discloses a heat exchanger that has among its objects to cool fuel in the fuel system of a vehicle, wherein the cooler has been inserted between two conduits in the return conduit. However, this cooler is very space-intensive, and in that cooler a very large loss of pressure occurs in the return conduit which means that a large pumping capacity is required to return the amount of fuel in the return conduit to the tank. EP-0 807 756 teaches a fuel system for a vehicle wherein a tubular section is inserted that has axially oriented cooling ribs for cooling the fuel in the advance and return conduits in the fuel system. At each of its ends, this tubular section is connected by means of tubes to the motor and tank installations, respectively. The tubu- lar section comprises two parallel flow conduits and is provided with cooling ribs that allow the fuel to be cooled in a simple manner by the streams of air underneath the bottom of the vehicle. The fuel system according to EP-0 807 756 eliminates the drawbacks in connection with pressure drops and large pumping capacity, and usual tubing underneath the bottom is also utilised which saves space compared to previously. However, dirt may accumulate on this cooling profile that may deposit on top of and between the cooling ribs and thus reduce the cooling effect or even have an insulating effect on the profile tubing. Moreover, this known type of fuel pipe comprises mechanical joints, eg soldered joints between eg fuel tubing, connector tubing and cooler tubing. Such joints present a risk of leak. This risk is greatly increased when the fuel is to be advanced in the fuel pipe under pressure. It is therefore desirable to be able to manufacture a fuel system with a minimum of joints, especially welded joints and soldered joints, in order to hereby reduce the risk of leaks oc- curring due to a weak joint. In case of motors based on recently developed technology, a marked increase in the pressure and temperature of the fuel may occur. The temperature may become extremely ele- vated which gives rise to problems in connection with fuel tanks made of plastics and/or components in connection therewith, and likewise the fuel, eg the diesel oil, may react chemically with the plastics parts of the tank whereby the tank as well as the fuel can suffer damage. Moreover the fuel can also suffer damage eg as a consequence of boiling at the elevated temperatures. In the light of this it is, in connection with such novel motor installations, of the utmost importance to cool the fuel effectively, and many producers thus require that the temperature of the fuel must be kept below a suitably low temperature . In the light of this it is the object of the invention to provide a flow conduit that remedies the above-mentioned drawbacks, and whereby the stipulated requirements to cooling can be complied with. The invention consists of a flow conduit of the kind described above wherein the surface-enlarging means comprise cooling blades that extend outwards and/or down- wards from surface parts of the flow conduit, and in that said flow conduit features an upwardly facing surface portion which is exclusively planar and/or convex. With a flow conduit according to the invention for cool- ing fuel, adequate cooling of the fuel is obtained in all conditions. The particular configurations of the flow conduit and the surface-enlarging means prevent accumulation of dirt in the spaces between the cooling blades, or on the upwardly facing surface part of the profile, since dirt, if any, will drop out of the spaces and the upwardly facing surface portion by itself. The surface- enlarging means on the flow conduit are thus self- cleaning. The configuration shown in claim 2, wherein the cooling blades of the flow conduit feature a bendable base section and a section provided with cooling fins, allows the profile to be extruded with a relatively flat contour following which the cooling blades can be bent downwards to become self-cleaning. Thus, in the preferred embodiment of the profile according to the invention, the cooling fins in the outer section are inclined relative to the cooling blades in such a manner that the cooling fins point away from the tubular section. Moreover, two cool- ing blades can be provided that are, at their base sections, bendable in such a manner that the cooling fins exhibit downwardly inclining surfaces. Hereby the self- cleaning function is ensured on both sides of the cooling blades, the cooling fins on both sides of the cooling blades all featuring a downwardly inclining surface. The flow conduit according to the invention is in one embodiment an extruded aluminium profile. Aluminium is extremely heat-conductive and easily deformable which means that the profile according to this embodiment is uncom- plicated to manufacture by extrusion and, the material thus chosen also yields an adequate cooling effect. In one embodiment of the flow conduit, it is made with internal cooling fins. Hereby a further cooling of the flow medium in the conduit is obtained. In a further embodiment the flow conduit consists of several interconnected elements comprising an internal tubular element, and an external cooling element with cooling blades, wherein the outer surface of the tubular elements abuts on surface portions of the cooling element. Hereby the cooling element with the cooling blades can be mounted subsequently on those sections of the flow conduit where it is most convenient. For instance, the cooling element can be soldered onto the surface of the flow conduit to provide adequate thermal connection between the flow conduit and the cooling element. Also, attachment by mechanical deformation may result in an adequate thermal connection between the elements and is therefor a further option. Additionally, the invention relates to a fuel pipe configured as a flow conduit according to the first aspect of this invention wherein the flow conduit exhibits one or more areas of angulation or attachment, wherein the cooling blades have been removed, and wherein, essen- tially, the flow conduit thus merely consists of a tubular element. The fuel pipe according to this aspect of the invention is configured in one piece and thus it does not feature soldered joints, welded joints or the like joints that weaken the strength of the flow conduit. Hereby the risk of leaks is considerably reduced. In a preferred embodiment of the fuel pipe according to the invention, the cooling blades have been cut off or in other way removed from the tubular element at least at the one end of the profile, and the tubular element is configured with coupling means for coupling to a tank or motor installation. Hereby it is possible to configure a coupling stud in the tubular element at the end of the conduit. This means that the number of joints in connection with the conduit is further reduced, mounting of coupling means on the fuel pipe no longer being necessary when a fuel pipe having this embodiment of the invention is used. In the preferred embodiment the conduit is a return conduit in the fuel system of a diesel-driven vehicle. In particular the return flow of a diesel motor requires cooling of fuel. The cooling profile as well as the fuel pipe according to the invention are primarily intended for cooling return fuel in connection with a diesel- driven vehicle, but it has also been found in connection with the invention that the flow conduit and the fuel pipe can also be used for other cooling tasks, including cooling of fuels other than diesel. In a method of manufacturing a fuel pipe of a profile ac- cording to the invention, the cooling profile is extruded whereby a tubular element is formed having a flow conduit and one or more cooling blades that extend diametrically from the tubular element wherein the cooling blade (s) exhibit (s) a bendable base section and an outer section provided with cooling fins, and wherein the profile is subsequently shaped in accordance with the installation specifications for the fuel pipe. In a method according to the invention the profile can be extruded in any length. In the subsequent shaping the profile is shortened to the desired length. Then the remaining shaping is effected, such as bending and adaptation to fittings relative to the bottom of the vehicle on which the fuel pipe is to be mounted. In connection with this shaping the method preferably further comprises a notching of the cooling blades in one or more sections of the profile, and the tubular section of the profile is subsequently bent in one or more of the sections. Removal of the cooling blades in those sections of the profile where it is to be bent will facilitate this angulation, the cooling blades otherwise bracing the tubular element. In a preferred embodiment of the invention the profile can be bent to the desired shape of the fuel pipe, following which the cooling blades in the cooling profile are bent at their base sections in such a manner that the cooling fins exhibit downwardly inclining faces. Such downward angulation can optionally be carried out immedi- ately prior to the mounting of the fuel pipe in the vehicle by the manufacturer or the repairer of the vehicle. In the following the invention will be described in further detail with reference to the accompanying drawings, wherein Figure 1 schematically illustrates a fuel system with a profile for cooling fuel in accordance with the invention; Figure 2 is a cross sectional view of a profile according to a preferred embodiment of the invention; Figure 3 is a cross sectional view of a shaped profile for use as fuel pipe according to the invention; Figure 4 is a schematical view of the bottom of a vehicle with a fuel pipe according to the invention; and Figure 5 is a schematical view of a fuel pipe according to the invention. Figure 1 shows the fuel system between a tank 1 and a motor 2. In an advance conduit 3 the fuel flows from the tank 1 and onwards to the motor 2. Excessive fuel is con- veyed back to the tank 1 via a return flow 4. In case of a diesel-driven motor 2 a part of the fuel is used for lubrication of eg pumps in the motor 2, and therefore the amount of fuel conveyed to the motor 2 exceeds the amount combusted. In a diesel motor the fuel can thus be circu- lated in an amount of about thrice the tank volume. The fuel is heated by passage through the motor installation 2, and accordingly it is necessary to cool the fuel in the return conduit 4. The return flow 4 is therefore provided with a fuel pipe according to the invention for cooling the fuel flowing therethrough to ensure that the fuel will neither, due to too elevated temperature, destroy the tank nor, due to chemical reacation with material in connection with the tank, will the combustibility of the fuel be reduced, eg by boiling, but is kept cooled to a harmless suitably low temperature. This fuel pipe is configured in a cooling profile 5 as shown in the cross sectional views of Figures 2 through 4. Figure 2 illustrates the preferred embodiment of a pro- file 5 for cooling fuel in accordance with the invention. The profile 5 is an extruded aluminium profile that exhibits a centrally arranged tubular element 6 in which a flow conduit 11 is configured. The profile 5 is configured with two cooling blades 7 that extend diametrically from the tubular element 6. Each cooling blade 7 exhibits a bendable base section 8 and an outer section 9 that comprises a number of cooling fins 10. In a preferred embodiment the flow conduit 11 in the tu- bular element 6 is provided with internal cooling ribs 17 whereby the cooling effect of the aluminium profile can be further increased. As shown in Figure 3, the cooling blades 7 can be bent in the base section 8 whereby the cooling fins 10 in the outer section 9 feature downwardly inclined surfaces 12. Hereby dirt will slide off the cooling fins 10 that thus continue to have a cooling effect. Angulation of the cooling blades 7 means that the cooling profile 5 accord- ing to the invention will appear as compact and it will retain a high cooling surface. It being also substantially self-cleaning, the profile 5 according to the invention is suitable for use as a fuel pipe. Figure 4 shows how the profile 5 can be mounted underneath the bottom 13 of a vehicle. It has been found in connection with the invention that the cooling fins 10 can alternatively or as supplement also be configured in the bendable section 8. Figure 5 shows a fuel pipe 4 configured in a cooling profile 5 according to the invention. The pipe 4 is configured with a number of sections 14,15,16 wherein the cooling blades have been removed. Thus in the sections 14, the tubular element is thus essentially exposed whereby angulation of the tubular element is considerably facilitated, in particular in the light of the angulations often having different orientations since the configuration of the fuel pipe is a spatial shape. Also, the cooling blades 7 can be removed by cutting-off or the like in one or more sections 15 in order to create space for fittings (not shown) . At each of the end sections 16 of the cooling profile 4, the cooling blades 7 have also been removed which means that in the tubular portion 6 a connecting branch can be configured that matches the reception opening in tank and motor installations 1,2, respectively. It has further been found in connection with the invention that within the tubular element two or more flow conduits 11 can be extruded in the right circumstances. In a not shown embodiment the flow conduit is built by means of two units in that a cooling element with cooling fins and/or cooling ribs have been attached to surface portions of a tubular element. In that case, the cooling element is preferably attached to surface portions that face sideways or downwards, and the cooling fins extend outwards or downwards relative to the tubular portion. A flow conduit having this configuration is suitable for mounting underneath the bottom of a vehicle, since it is possible to arrange the cooling element (s) according to desire on those areas of the tube that are not bent and where there are no fittings or the like for securing the pipe. The cooling element can eg be soldered or attached by deformation to the pipe in order to hereby provide adequate heat conductivity between the tubular element and the cooling element.

Claims: C l a i s 1. A flow conduit and surface-enlarging means for cooling the fluid in the flow conduit, c h a r a c t e r - i z e d in that the surface-enlarging means comprise cooling blades that extend outwards and/or downwards from surface portions of the flow conduit; and in that the flow conduit exhibits an upwardly facing surface portion that is exclusively planar and/or convex. 2. A flow conduit according to claim 1, c h a r a c t e r i z e d in that the cooling blades extend diametrically to either side of the flow conduit, said cooling blades exhibiting a bendable base section and an outer section provided with cooling fins. 3. A flow conduit according to claim 2, c h a r a c t e r i z e d in that the cooling fins in the outer section are inclined relative to the cooling blades in such a manner that the cooling fins point away from the flow conduit. 4. A flow conduit according to claim 2 or 3, c h a r a c t e r i z e d in that two cooling blades are pro- vided; and that the cooling blades are, at their base sections, bent in such a manner that the cooling fins exhibit downwardly inclining faces. 5. A flow conduit according to any one of the preceding claims, c h a r a c t e r i z e d in that the conduit is an extruded aluminium profile. 6. A flow conduit according to any one of the preceding claims, c h a r a c t e r i z e d in that at least one flow conduit in the profile is configured with internal cooling fins. 7. A flow conduit according to one or more of the preceding claims, c h a r a c t e r i z e d in that the flow conduit is composed of several elements comprising an internal tubular element and an external cooling element with cooling blades, wherein the outer surface of the tubular element is in abutment on surface portions of the cooling element. 8. A fuel pipe with one or more angulations for establishing flow communication between a tank and a motor installation in a vehicle, c h a r a c t e r i z e d in that the fuel pipe is configured as a flow conduit according to any one of claims 1 through 7, said flow con- duit exhibiting one or more angulation or attachment areas without cooling blades, and wherein the conduit thus essentially consists of only a tubular element. 9. A fuel pipe according to claim 8, c h a r a c - t e r i z e d in that the cooling blades have been cut-off or in other way removed from the tubular element at least at the one end of the profile; and that the flow conduit is configured with coupling means for connection to a tank or motor installation. 10. A fuel pipe according to claim 8 or 9, c h a r a c t e r i z e d in that the pipe is a return conduit in the fuel system of a diesel-operated vehicle. 11. A fuel pipe according to claim 10, c h a r a c t e r i z e d in that the pipe is an advance conduit in the fuel system of a diesel-operated vehicle. 12. A method of manufacturing a fuel pipe according to claims 8 through 10 from a flow conduit according to claims 1 through 7, c h a r a c t e r i z e d in that the flow conduit is extruded as a profile whereby a tubular element is formed with a flow conduit and having one or more cooling blades that extend diametrically from the surface portions of the flow conduit and which ex- hibit(s) a bendable base section and an outer section provided with cooling fins; and that the profile is subsequently shaped in accordance with the installation specifications of the fuel pipe. 13. A method according to claim 11, wherein a notching of the cooling blades is carried out in one or more sections of the profile; and wherein the tubular element of the profile is subsequently bent in one or more of the sections . 14. A method according to claim 12, wherein the cooling blades in the cooling profile is bent at its base sections in such a manner that the cooling fins exhibit downwardly inclining faces.

Inventors: BOYSEN KARL, JOHNSEN PETER, KOEHLING PETER N, VON HUTH SMITH ULF, BOYSEN, KARL, JOHNSEN, PETER, KOEHLING, PETER, N., VON HUTH SMITH, ULF
Applicants: BOYSEN KARL, JOHNSEN PETER, KOEHLING PETER N, NORSK HYDRO AS, VON HUTH SMITH ULF, BOYSEN, KARL, JOHNSEN, PETER, KOEHLING, PETER, N., NORSK HYDRO ASA, VON HUTH SMITH, ULF
Application year: 1999
Main classification: F28F1
IPC codes: F02M31, F16L11, F28D1, F28F1