SE540120C2

SE540120C2 - Fuel filter device, fuel tank, fuel system and a vehicle comprising the fuel filter device

Info

Publication number: SE540120C2
Application number: SE1651397A
Authority: SE
Inventors: berg Adam
Original assignee: Scania Cv Ab
Priority date: 2016-10-26
Filing date: 2016-10-26
Publication date: 2018-04-03
Also published as: DE102017009399B4; SE1651397A1; BR102017022189A2; BR102017022189B1; DE102017009399A1

Abstract

The present invention relates to a fuel filter device (12) comprising a support body carrying a filter element (43), the support body comprising a first end portion (41) and a second end portion (42) and a hollow cylindrical central tube (31) extending between the first and second end portions and the filter element (43) radially surrounding the hollow tube (31). The central tube comprises apertures and the device (12) further comprises a hollow cylindrical venting tube (44) arranged in the hollow central tube (31), the venting tube extending between the first and second end portions (41; 42) and outside beyond the first end portion in a longitudinal direction (L) of the device, and wherein the cylindrical sidewall (48) of the venting tube (44) comprises apertures along the length of the venting tube extending between the first and second end portions, and wherein the cylindrical sidewall (48) of the venting tube (44) is solid over the length extending beyond the first end portion and comprises an outlet opening (36) through which filtered fuel and air are arranged to flow.

Description

1 Fuel filter device, fuel tank, fuel system and a vehicle comprising the fuel filter deviceTECHNICAL FIELD The present invention relates to a fuel filter device, fuel tank comprising the fuel filter deviceand a fuel system comprising the fuel tank. The present invention also relates to a vehicle comprising the fuel filter device, the fuel tank or the fuel system.BACKGROUND ART Internal combustion engines are driven by fuel and the engine is equipped with a fuel systemto transport fuel from one or several fuel tanks to the internal combustion engine's injectionsystem. The fuel system usually comprises a low pressure circuit and a high pressure circuit,where the low pressure circuit comprises one or several fuel pumps/supply pumps, which maybe operated mechanically by the internal combustion engine or by an electric motor. The fuelpumps pressurize the fuel and thus create a fuel flow whereby the fuel can be transported tothe high pressure circuit and an accumulator, which may in the form of a so-called commonrail, and further to the combustion engine's injection system, which supplies the fuel to thecombustion engine's combustion chamber. Common rail may be excluded and the fuel systemmay instead comprise another form of an injection system, for example a piezo- or a unit injection system.

The fuel system also comprises at least one fuel filter for filtration of the fuel before it reachesthe internal combustion engine's injection system. The internal combustion engine and itsinjection system are sensitive to impurities and air bubbles. Air bubbles may accumulate in thefuel filter whereby start problems for the engine are caused. Therefore, it is crucial to arrangewith adequate venting ofthe fuel filter. Today's solutions are often complicated and requirethe use of separate venting devices, such as valves, which increase the space requirementsand weight of the components in the fuel system. However, the venting valves are notsufficient to prevent the starting problems, but instead are used when the starting problemshave already occurred. Also, the valves require maintenance and service. Therefore, there is aneed for more effective and simpler venting arrangements that also can prevent the starting problems. 2Venting problems have been realized for example in US2004/0065305 A1. ln the solution, aventing pipe is connected to a downstream side of a fuel filter and an upper air-space in a fueltank. However, the solution is space demanding. Thus despite prior art solutions in the field, there is still a need to improve the venting systems.SUMMARY OF THE INVENTION The objective ofthe present invention is to provide a fuel filter device, which can easily andreliably be vented or deaerated, i.e. removed of gas or air. Further, it is an objective ofthepresent invention to decrease problems with starting an internal combustion engine. lt is also an objective to provide a fuel filter device with a simple and light construction. lt is also an objective of the present invention to provide a fuel filter device which can beplaced in a fuel tank in a space saving way while the fuel filter device can be effectivelyvented. lt is also an objective ofthe invention to provide a space saving fuel tank which enables effective venting of a fuel filter device.

Furthermore it is an objective ofthe present invention to provide a fuel filter device for a fuelsystem in which the fuel filter can be deaerated or vented effectively without a need for heavyand structurally complicated venting components and valves. Further, it is an objective toprovide a fuel system with a space saving, robust and light construction with a decreased amount of components.Further, it is an objective to provide a vehicle having the advantages above.

These objectives are achieved with a fuel filter device, fuel tank, fuel system and vehicle ofthe type specified by the features of the appended claims.

Especially, the present invention relates to a fuel filter device comprising a support bodycarrying a filter element, the support body comprising a first end portion and a second endportion and a cylindrical hollow central tube extending between the first and second endportions. The filter element surrounds radially the hollow central tube. A wall of the hollowcentral tube comprises apertures along the length of the central tube. ln this way, fuel can bepressed inside the hollow central tube. The fuel filter device further comprises a hollowcylindrical venting tube arranged in the hollow central tube. The venting tube comprises a portion extending between the first and second end portions and an end portion extending 3 outside beyond the first end portion ofthe support body in a longitudinal direction of the fuelfilter device. A wall of the venting tube comprises apertures along the length ofthe ventingtube extending between the first and second end portions. ln this way the fuel can be furtherpressed through the central tube ofthe support body and through the wall ofthe venting tubetowards a center ofthe venting tube. The wall ofthe venting tube is solid over the lengthextending beyond the first end portion and comprises an outlet opening through whichfiltered fuel and air are arranged to flow. Thus, when the fuel is fed to the fuel filter device, itpasses through the cylindrical filter element towards the center of the fuel filter device. Thefuel is then pressed upwards towards the solid portion of the venting tube. Air or gasgenerated in the fuel filter device is then removed from the fuel filter device when the fuel ispressed through the outlet opening. After the outlet inlet, the fuel flows downwards to theinterior ofthe fuel tank and air or gas stays in the atmosphere in the fuel tank and will bevented through a fuel tank venting arrangement from the interior ofthe fuel tank. Thus, thefuel filter device ofthe present invention has means enabling reliable, effective and naturalventing of the fuel filter device. The construction of the fuel filter device is compact, while the venting tube improves the mechanical stability of the fuel filter device.

The wall of the venting tube may comprise a plurality of wing elements extending radiallyoutwards from the wall of the venting tube. Each of the wing elements is angled downwardstowards the second end portion of the support body and in respect to a longitudinal centrumaxis of the fuel filter device at an angle which is greater than 90° such that fuel entering theventing tube is directed upwards towards the first end portion of the filter device. ln this way,fuel flow can be directed upwards towards the end portion of the venting tube in a simple mannef.

The first end portion and the second end portion comprise, or the first end portion or thesecond end portion comprises means to attach the fuel filter device to a fuel tank housing. lnthis way secure connection between the fuel filter device and the fuel tank housing can beprovided. The means to connect the fuel filter device to the fuel tank housing in the secondend portion may comprise a cap device. The cap device is suitably adapted to collect waterseparated from the fuel by the filter element. ln this way no separate water collecting device is needed and thus, a simple construction for the fuel filter device is provided. 4The end portion of the venting tube extending beyond the first end portion of the filter devicecan be provided with a |id device having means to direct the flow of fuel downwards towardsthe second end portion of the filter device. ln this way the flow of fuel, which is in liquidphase, can be effectively directed downwards, while gas and air in gaseous phase flowupwards towards a top portion of the fuel tank housing interior. Air of gas from the interior ofthe fuel tank can then be vented in a traditional manner, e.g. by means of a venting opening and/or tube attached to the top portion ofthe fuel tank.

The present invention also relates to a fuel tank which comprises a fuel filter housingsurrounding at least a portion of the fuel filter device described above. The filter housing maybe formed as a cavity extending at least partly inside the fuel tank housing. Alternatively, thefuel tank housing may comprise an opening into which a filter housing is fitted. The fuel tankcomprising the fuel filter device of the present invention inside the fuel tank housing iscompact. Furthermore, the fuel tank housing provides protection for the fuel filter device, andthus the fuel filter housing inside the fuel tank housing can be made of a material that is lightand has lower mechanical strength against forces from the outside than fuel filter housingslocating outside the fuel tank. Thus, the weight of a fuel system comprising the fuel filterdevice and the fuel tank of the present invention can be decreased, which leads to e.g. decreased fuel consumption.

The fuel filter housing is arranged to contain the support body and the filter element and theportion of the venting tube extending between the first and second end portions of thesupport body, and wherein the filter housing comprises a first opening through which the endportion of the venting tube extends. The wall of the end portion of the venting tube is solidand thus, fuel pressed through the fuel filter device will be fed upwards towards the topportion of the fuel tank housing, whereby gas and air can be naturally and effectively removed from the fuel flow.

The fuel filter housing is suitably arranged below the fuel level, e.g. the highest nominal fuellevel of the fuel tank and at least a part of the solid venting tube portion is arranged above thefuel level. ln this way, the fuel filter device is protected and cooled down by the fuel. Also thegas or air in the fuel can be easily removed to the atmosphere of the fuel tank when the end portion, and thus the outlet in the venting tube are located above the fuel level. 5Suitably, the fuel tank housing comprises attachment means to connect the fuel filter deviceto the fuel tank housing, wherein at least a portion of the attaching means are located outside the fuel tank housing.

Preferably, the fuel filter housing comprises an opening for a fuel conduit through which fuel isfed into the filter device. ln this way the unfiltered fuel can be fed to the fuel filter at a desiredlocation, and the construction of the fuel system can be adapted to specific conditions of the fuel system.

According to a further embodiment, the fuel tank further comprises at least one fuel pump. lnthis way, a more compact construction may be provided while the fuel tank provides protection for the different components of a fuel system.

Preferably, the fuel tank comprises venting means to deaerate the tank. ln this way, the pressure inside the tank can be regulated and controlled in a reliable way.

The present invention further relates to a fuel system for an internal combustion engine, thefuel system comprising a main fuel tank, a technology tank, a first fuel conduit connecting themain fuel tank and the technology tank, a first fuel pump arranged to feed fuel from the mainfuel tank to the technology tank through the first fuel conduit, and a fuel filter device arrangeddownstream of the first fuel pump. The technology tank comprises a filter housing arranged tosurround at least a portion of a fuel filter device comprising a support body carrying a filterelement. The support body comprises a first end portion and a second end portion and ahollow cylindrical central tube extending between the first and second end portions. The filterelement surrounds the central tube, which comprises apertures. The fuel filter device furthercomprises a hollow cylindrical venting tube arranged in the hollow central tube. The ventingtube extends between the first and second end portions and outside beyond the first endportion in a longitudinal direction of the fuel filter device. A wall of the venting tube comprisesapertures along the length of the venting tube extending between the first and second endportions. The wall portion of the venting tube extending beyond the first end portion is solid.The first fuel pump is arranged to feed fuel through the fuel filter device via the first fuelconduit and an opening in the fuel filter housing through the filter element and upwards through the solid wall portion of the venting tube, whereby the fuel filter device is vented. 6The present invention also relates to vehicle comprising the fuel filter, a fuel tank or a fuel system as defined above.

Further features and advantages ofthe present invention will be described in more detail in the detailed description below with reference to the attached drawings.BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a schematic side view of a vehicle, which comprises a fuel filter device, a fuel tank and a fuel system for an internal combustion engine according to the present invention,Fig. 2 shows a coupling diagram for a fuel system according to the present invention, Fig. 3a and 3b show embodiments of a fuel tank comprising the fuel filter device according to the present invention in a schematic partly cut view.Fig. 4a shows a schematic side view of a fuel filter device according to the present invention, Fig. 4b shows a longitudinal cut view of the fuel filter device without the venting tube shown in Fig. 4aFig. 4c shows a schematic side view of the venting tube.DETAILED DESCRIPTION Generally, fuel systems include at least one fuel filter and fuel pump to supply an internalcombustion engine with fuel. In modern fuel systems at least one low pressure pump and atleast one high pressure pump are usually provided to pressurize fuel. Also, the fuel systemusually comprises one or more fuel filter devices that filter the fuel from impurities and e.g.water. When the internal combustion engine is in operation, the fuel is supplied to the filterdevice via a first fuel conduit with a certain pressure from a low pressure pump, followingwhich the fuel passes through the filter element and impurities are filtered out. Subsequently,the fuel is supplied further along to a high pressure pump and the internal combustionengine's injection system. In the prior art solutions a substantially negligible part ofthe fuelhas passed through a venting outlet arranged in a filter housing for deaeration. Thereby, it hasbeen difficult to fully deaerate the fuel. Also, the filter housings and venting outlets have required the use of valves to release air, gas or vapour from the filter device, which have made 7the venting systems complicated and space demanding. However, according to the presentinvention, all fuel is pumped through an outlet opening in a venting tube of the fuel filterdevice. ln this way, a natural deaeration of the fuel can be obtained, and all fuel can be deaerated and the fuel filter device vented.

According to the present invention the fuel filter device comprises a support body carrying afilter element, the support body comprising a first end portion and a second end portion and ahollow cylindrical central tube extending between the first and second end portions. Thesupport body is made of a material that tolerates the conditions in fuel systems and can bemade of plastics or stainless steel. The filter element surrounds the hollow central tube. Thefilter material may be any conventional material used for fuel filtering and can be for examplepaper-based. The central tube of the support body comprises apertures that allow the fuelpass through the central tube. The device further comprises a hollow cylindrical venting tubearranged in the hollow central tube. Suitably, the venting tube has a size and shape that matewith the central tube ofthe support body. The venting tube extends between the first andsecond end portions and outside beyond the first end portion in a longitudinal direction ofthedevice. ln addition, the cylindrical sidewall ofthe venting tube comprises apertures along thelength of the venting tube extending between the first and second end portions to allow fuelto pass through the venting tube. The cylindrical sidewall of the venting tube is solid over thelength extending beyond the first end portion and comprises an outlet opening through which filtered fuel and air are arranged to flow.

When an internal combustion engine is turned off, no fuel needs to be supplied to the internalcombustion engine and accordingly the low pressure pump and the high pressure pump areusually deactivated, and the pressure in the fuel system drops. When the internal combustionengine is started again, a rapid pressure build-up in the fuel system is required, in order toenable sufficient supply of fuel to the internal combustion engine. The low pressure pumpmust then be controlled towards a high rotational speed, in order to be able to supply fuelthrough the fuel filter device with a sufficiently high pressure. During the operation of theinternal combustion engine air may enter the fuel filter device, which may cause difficulties tostart the internal combustion engine. Thereby sufficient venting of the fuel filter device is critical to avoid problems with starting ofthe engine. 8 The fuel system in which the fuel filter device of the present invention is suitable for usecomprises two fuel tanks, a main tank referred to as a first fuel tank and a technology tankreferred to a second fuel tank. Suitably, the second fuel tank is adapted so that it holds asmaller volume than the first fuel tank, which is easier to arrange inside a chassis with limitedspace. Thus, a non-bulky fuel system is achieved. Preferably, a first fuel pump, also referred toas a transfer pump is arranged to supply the second fuel tank with fuel. The transfer pumpsuitably supplies fuel from the first fuel tank, via a first fuel conduit, further to the second fueltank. The fuel filter device of the present invention is arranged downstream of the first fuelpump, i.e. transfer pump, and upstream of a second fuel pump, i.e. a main low pressure pump,which may be arranged in the second fuel tank. The fuel reaching the main low pressurepump, which may be operated by an electric motor or which may be mechanically driven byan internal combustion engine, is thus filtered, which entails that the main low pressure pumpis protected against impurities in an advantageous manner, which reduces the risk ofoperational disruptions in the main low pressure pump. The first fuel pump, i.e. the transferpump can also be operated by an electric motor or mechanically by the internal combustionengine. Suitably the main low pressure pump is arranged in the second fuel tank, but may bearranged separately outside the tank in the chassis. By arranging the main low pressure pumpin the second fuel tank, the main low pressure pump is protected from the environment, and anatural cooling of the fuel in the second fuel tank is obtained. The transfer pump may bearranged outside the tank in the chassis or alternatively it may also be arranged inside the second fuel tank.

The low pressure pumps in modern fuel systems are often operated by electric motors,whereby a broader control interval is allowed than with a mechanical pump, which is usuallyoperated and controlled by an internal combustion engine and in particular by the enginespeed ofthe internal combustion engine. The low pressure pumps operated by an electricmotor may be controlled towards other parameters than rotational speed, e.g. pressure insidethe fuel conduits. The low pressure pump's electric motor is suitably arranged in connectionwith a control device via a communication bus. Signals may be received and sent via aconnection consisting of one or several cables, which may be a CAN-bus (Controller AreaNetwork), I\/IOST-bus (I\/|edia Oriented Systems Transport), or some other type of bus configuration, or a wireless connection. The control device may be a separate control device 9for the electric motor ofthe low pressure pump, or alternatively the control device mayconsist of logic in a control device for the internal combustion engine. The vehicle's other control devices may in their turn also be connected to the CAN-bus.

Other advantages of the invention are set out in the detailed description of the invention's example embodiments below.

Fig. 1 shows a schematic side view of a vehicle 1, which vehicle comprises a fuel system 4 foran internal combustion engine 2 according to the present invention. The internal combustionengine 2 is connected to a gearbox 6, which is further connected to the driving wheels 8 ofthe vehicle 1 via a transmission. The vehicle also comprises a chassis 10.

Fig. 2 shows a coupling diagram for a fuel system 4 in an internal combustion engine 2according to the present invention. The fuel system 4 comprises several components, amongwhich a main fuel filter 18, a high pressure pump 14, an accumulator in the form of a so-calledcommon rail16, and an injection system 17 schematically displayed in the form of a fuelinjector, are arranged in the internal combustion engine 2 (the internal combustion engine 2 isshown in Fig. 1). Alternatively, the common rail 16 may be replaced by another form ofinjection system 17, e.g. a piezo- or a unit injection system. The high pressure pump 14, thecommon rail 16 and the injection system 17 constitute components in the high pressure system 19 of the fuel system 4.

The fuel system 4 also comprises a main fuel tank 20, a first low pressure pump 22 referred toas a transfer pump, a first fuel conduit 24, through which the transfer pump 22 is arranged tosupply fuel to a fuel filter device 12, which is a filter device according to the present invention.A control device is suitably arranged in connection with an electric motor I\/|1 to operate thetransfer pump 22. The control device can be arranged in connection with the electric motorI\/|1 via a communication bus. During normal operation of the internal combustion engine 2 orduring the ignition of the internal combustion engine, the transfer pump 22 pumps fuel fromthe main fuel tank 20 through the fuel filter device 12 to a second fuel tank 30 referred to as atechnology tank, arranged downstream of the transfer pump 22. The fuel is then pumpedfrom the second fuel tank 30 further through a main fuel filter 18 to the high pressure pump 14, which then pumps the fuel further to the internal combustion engine 2.

The fuel system may also comprise an additional main fuel tank. The main tanks may be intheir respective top parts connected with a ventilation conduit communicating with thesurrounding environment via an air filter. Also the technology tank may comprise a ventilationconduit in connection with the surrounding atmosphere. The ventilation conduit ensures thatthe pressure in the respective fuel tanks is and remains substantially the same, and is equal tothe ambient air pressure, regardless of how much fuel is in the respective tanks. The air filterprevents impurities in the surrounding air from penetrating into the ventilation conduit in connection with ventilation ofthe tanks.

The technology tank 30 may be adapted to hold a smaller volume than either one ofthe mainfuel tanks. However, the volume may also be the same or even larger than the volume of themain fuel tanks. The main fuel tanks preferably hold substantially the same volume and have aself-regulating flow between each other. The first fuel pump, i.e. the transfer pump 22 is,according to Fig. 2, arranged between the main fuel tank 20 and the technology tank 30. Thetransfer pump 22 may be arranged inside the technology tank 20, and is thus protected fromthe environment and cooled by the fuel. The transfer pump 22 can be operated by anelectrical motor I\/|1, and its main task is to supply fuel from the main fuel tank 20 to the technology tank 30, via a first fuel conduit 24.

Between the first fuel tank 20 and the second fuel tank 30 an overflow conduit 46 is arranged,so that fuel may be transported from the technology tank 30 to the main fuel tank 20, if the technology tank 30 becomes overfilled.

The fuel filter device 12 of the present invention is arranged in the second fuel tank, i.e. thetechnology tank 30 downstream of the transfer pump 22 and comprises preferably a finemesh, water separating filter element. ln the main fuel tank 20, upstream ofthe transferpump 22, a coarse mesh sieve 48 is arranged, through which the transfer pump 22 sucks fuel.The coarse mesh sieve 48 filters away particles above a certain predetermined size. Thetransfer pump 22 then pressurizes the fuel and feeds it through the filter device 12 furtheralong to the technology tank 20, via the first fuel conduit 24. The fuel in the technology tank30 has thus passed both the coarse mesh sieve 48 and the filter device 12 with fine mesh filterelement, which entails that the main low pressure pump 26, which is arranged in the second fuel tank 30, is protected against impurities. 11 The main fuel filter device 18 comprises a filter house 50, in which a filter element 52 isarranged, through which fuel from the second fuel tank 30 is filtered. The filter house 50 has adeaeration outlet 54, with which an overflow conduit 56 is connected. The overflow conduit56 is also connected with the technology tank 30. ln this manner, fuel may flow from the filterhouse 50, through the deaeration outlet 54, further along through the overflow conduit 56and back to the technology tank 20, when the internal combustion engine 2 is turned off andthe low pressure pump 22 is active. When the internal combustion engine 2 is in operation,the filter house 50 is deaerated via the deaeration outlet 54. A valve device 58 in the form of athrottle valve may be arranged at the deaeration outlet 54, and thus in connection with theoverflow conduit 56. The overflow conduit 56 is also used to lead warm fuel from the high pressure pump 14 back to the second fuel tank if necessary.

A fuel level sensor 62 can be arranged in the technology tank 30, in order to identify the fuellevel. When the fuel level in the second fuel tank, i.e. technology tank 30, determined with thelevel sensor 62, falls below a predetermined level threshold, the transfer pump 22 iscontrolled to feed fuel from the main fuel tank 20 to the technology tank 30. A pressuresensor 66 is arranged downstream ofthe main fuel filter 18. The pressure sensor can beconnected to a vehicle control device via a communication bus 28. The pressure sensor maycontrol the electric motor I\/|2, which operates the main fuel pump 26, by allowing a setpointvalue regardless of the conditions in the system, e.g. in case of a pressure drop in the system,regardless of the fuel filter clogging level or regardless of the optimal fuel requirements from the internal combustion engine 2, the injection system 17 or the control system. ln Fig. 3a and 3b examples of a fuel tank 30 according to the present invention are shown.Each of the tanks is a technology tank of a fuel system and may have a volume that is smallerthan, equal to or larger than the volume of the main fuel tank. The volume can thus varygreatly and can be as low as 5 litres and up to 200 litres, but is not limited to the range. Thetechnology tank 30 comprises a fuel tank housing 32 arranged to contain fuel 40. The fuel hasa fuel level and is illustrated in Fig. 3a and 3b with a line 37. The fuel level is monitored bymeans of the level sensor 62 as explained above. The fuel tank further comprises ventingmeans 33 to deaerate the tank 30. The venting means 33 can be simply an opening in the fuel tank housing 32 and optionally comprise a pipe of rigid or flexible material, such as plastic, to 12lead the air out from the interior of the tank 30. The fuel tank 30 comprises a filter housing 34surrounding at least a portion of the fuel filter device 12 inside the tank 30. By arranging thefilter housing 34 inside the tank, space required by different components can be effectivelysaved. The tank could also contain the transfer pump 22 and/or the main fuel pump 26 asillustrated in Fig. 2. ln this way, the low pressure pump or pumps may be protected from thesurrounding environment while further space can be saved in the vehicle. Also, since thepump or pumps and filter device are effectively protected by the fuel tank 30, lighter and lessrobust materials can be used for example for the filter housing. Using lighter materials is a huge advantage which will also lead to reduced fuel consumption.

Reference is now made to Fig. 4a-4c which schematically show the construction of the fuelfilter device 12. The fuel filter device 12 comprises a support body carrying a filter element 43,the support body comprising a first end portion 41, a second end portion 42 and a hollowcylindrical central tube 31 extending between the first and second end portions 41 and 42.The filter element 43 may be a paper-based fuel filter or any other known kind of filterelement. The support body may be made of a plastic material suitable for use in connectionwith different types of fuel. The filter element 43 radially surrounds the hollow central tube31. The central tube 31 comprises apertures through which the fuel and air can pass. The sizeand shape of the apertures may vary, but should be constructed such that the fuel may easilypass through the apertures without increasing the back pressure substantially. The fuel filterdevice 12 further comprises a hollow cylindrical venting tube 44 arranged in the hollow centraltube 31, the venting tube 44 extending between the first and second end portions 41 and 42,and outside beyond the first end portion 41 in a longitudinal direction L of the device. Thereference sign L also depicts the centrum axis of the fuel filter device 12. ln Fig. 4c, it can beseen that the venting tube 44 comprises a substantially cylindrical sidewall 48 with apertures49a along the length of the venting tube extending between the first and second end portions,and the size and shape of the apertures may vary. The wall 48 of the venting tube mayaccording to one embodiment additionally comprise a plurality of wing elements 48b, whichform apertures 48a connected to apertures 49a, which extend radially outwards from the wall48 of the venting tube 44. Each of the wing elements 48b extends in radial direction of thewall 48 and is angled downwards towards the second end portion 42 of the support body and in respect to a longitudinal centrum axis L of the fuel filter device 12 at an angle (a) which is 13greater than 900. ln this way fuel entering the venting tube is directed upwards towards thefirst end portion 41 of the filter device 12. However, the cylindrical sidewall 48 of the ventingtube is solid over the length extending beyond the first end portion 41, i.e. the end portion 47of the venting tube 44, but comprises at least one outlet opening 36, as shown in Fig. 3a and3b, through which filtered fuel and air are arranged to flow. Thus, the fuel entering the fuelfilter device 12 and the venting tube 44 can be easily directed upwards towards the first endportion 41 of the filter device 12 and the outlet opening 36. ln this way, air can be removed from the fuel in an efficient way and a natural deaeration of the fuel obtained.

Returning to Fig. 3a and 3b, preferably, the filter housing 34 is located in the fuel tank 30 sothat it is surrounded by the fuel 40 in the tank 30. ln this way, the filter device and the filterhousing can be effectively protected and the temperature of the fuel filter device can be keptat a fuel temperature level. The filter housing 34 is arranged to contain at least a portion ofthe fuel filter device 12 including at least a portion of the filter element 43 and venting tube44. Preferably, also the first end portion 41, which corresponds to a top portion of the filterdevice 12, and the second end portion 42, which corresponds to the bottom portion of thefilter device 12, are contained in the filter housing 34, whereby the filter element 43 and ahollow central tube 31 comprising apertures and the portion of the hollow cylindrical ventingtube 44 extending between the first and second end portions 41 and 42 arranged in the hollow central tube 31 are also completely contained in the filter housing 34.

The fuel filter housing 34 comprises a first opening 38 through which the end portion, i.e. thesolid part 47 of the wall of the venting tube 44 extends. The opening is located on the top sideof the fuel filter housing 34, i.e. in proximity of the first end portion 41 of the fuel filter device12. Suitably, the first end portion 41 comprises means 45 to connect the fuel filter device 12 tothe fuel tank housing 32, i.e. on the top part of the fuel tank housing as shown in Fig. 3a. Themeans may for example comprise a plastic piece or block provided with threads that can beconnected to a top cap having mating threads which thereby fixes the filter device 12 to thefilter housing 34. ln a corresponding way and as shown in both Fig 3a and 3b, the second endportion 42 may comprise means 35 to connect the fuel filter device 12 to the fuel tank housing32, i.e. at the bottom side of the fuel tank housing 32. ln the same way, the means maycomprise a plastic piece or block provided with threads that can be connected to a cap having mating threads which thereby fixes the filter device 12 to the filter housing 34. Preferably, the 14cap is a cap device 35' which can be used or is adapted to collect water separated from the fuel by the fuel filter element 43.

As shown in Fig 3a, the end portion 47 of the venting tube 44 (see Fig. 4c), that extendsbeyond the first end portion 41 of the filter device 12 is provided with a lid device 39 havingmeans to direct the flow of fuel downwards towards the second end portion 42 of the filterdevice 12. The lid device 39 is suitably located in proximity of the outlet opening 36. ln thisway the fuel flows downwards but air is allowed to escape to the interior of the fuel tank 30 and vented out through a venting opening 33.

As shown in Fig. 3a and 3b the filter housing 34 is arranged below the fuel level 37 and at leasta part of the solid venting tube portion 47 is arranged above the fuel level 37. ln this way, thefuel can flow downwards and air can escape upwards to the interior of the fuel tank 30. Themeans 35 in the first end portion 41 connecting the fuel filter device 12 to the fuel tankhousing 32 are arranged outside the fuel tank housing 32. ln this way easy maintenance and service ofthe fuel filter device can be provided.

The fuel filter housing 34 comprises an opening for a fuel conduit through which fuel is fedinto the filter device 12. The opening is preferably located in proximity of the bottom portionof the fuel filter device and fuel is preferably fed tangentially upwards towards the first end portion 41 of the fuel filter device 12.

The invention further relates to a fuel system or an arrangement in the fuel system for ventinga fuel filter device 12, and reference is made to Fig. 2-4c. As explained above, the fuel system4 comprises a main fuel tank 20, a technology tank 30, a first fuel conduit 24 connecting themain fuel tank 20 and the technology tank 30, a first fuel pump or transfer pump 22 arrangedto feed fuel from the main fuel tank 20 to the technology tank 30 through the first fuel conduit24. A fuel filter device 12 is arranged downstream of the first fuel pump 22. The technologytank 30 comprises a housing 32 surrounding at least a portion of the fuel filter device 12,which comprises a support body carrying a filter element 43, the support body comprising afirst end portion 41 and a second end portion 42 and a hollow cylindrical central tube 47extending between the first and second end portions. The filter element 43 surrounds thecentral tube 47 comprising apertures. The fuel filter device 12 further comprises a hollow cylindrical venting tube 44 arranged in the hollow central tube 47, the venting tube 44 extending between the first and second end portions 41, 42 and outside beyond the first endportion 41 in a longitudinal direction of the device 12. The wall 48 of the venting tube 44comprises apertures 48a along the length of the venting tube extending between the first andsecond end portions 41 and 42. The venting tube 44 comprises a solid wall 47 over the lengthextending beyond the first end portion 41. The transfer pump is arranged to feed fuel to thefuel filter device 12 via the first fuel conduit 24 and an opening in the fuel filter housing 34.The fuel is arranged to be fed upwards through the solid wall portion 47 of the venting tube,whereby the air from the fuel filter device 12 is deaerated, i.e. air or gas is removed from the fuel.

The components and features specified above may, within the framework of the invention, be combined between different embodiments specified.

Claims

16CLAll\/IS

1. A fuel filter device (12) comprising a support body carrying a filter element (43), the support body comprising a first end portion (41) and a second end portion (42) and acylindrical hollow central tube (31) extending between the first and second endportions and the filter element (43) radially surrounding the hollow central tube (31),characterized in that a wall of the hollow central tube comprises apertures along thelength of the central tube (31), and in that the fuel filter device further comprises ahollow cylindrical venting tube (44) arranged in the hollow central tube (31), theventing tube (44) comprising a portion extending between the first and second endportions (41; 42) and an end portion (47) extending outside beyond the first endportion (42) of the support body in a longitudinal direction (L) of the fuel filter device(12), and wherein a wall (48) of the venting tube (44) comprises apertures (48a; 49a)along the length of the venting tube (44) extending between the first and second endportions (41; 42), and wherein the wall (48) of the venting tube is solid over the lengthextending beyond the first end portion and comprises an outlet opening (36) through which filtered fuel and air are arranged to flow. Fuel filter device (12) according to claim 1, characterized in that the wall (48) of theventing tube (44) comprises a plurality of wing elements (48b) extending radiallyoutwards from the wall (48) of the venting tube, wherein each of the wing elements isangled downwards towards the second end portion (42) of the support body and inrespect to a longitudinal centrum axis (L) of the fuel filter device at an angle (a) whichis greater than 90° such that fuel entering the venting tube (44) is directed upwards towards the first end portion (41) of the filter device (12). Fuel filter device according to claim 1 or 2, characterized in that the first end portion(41) and/or the second end portion (42) comprises means (35; 45) to attach the fuel filter device (12) to a fuel tank housing (32). Fuel filter device according to claim 3, characterized in that the means (45) to connectthe fuel filter device (12) to the fuel tank housing (32) in the second end portion (42)comprises a cap device (35'), wherein the cap device (35') is adapted to collect water separated from the fuel by the filter element (12). 10. 11. 1

2. 17Fuel filter device according to any of claims 1 to 4, characterized in that the endportion (47) of the venting tube (44) extending beyond the first end portion (41) of thefilter device (12) is provided with a lid device (39) having means to direct the flow of fuel downwards towards the second end portion (42) of the filter device (12). A fuel tank (30) comprising a fuel tank housing (32) arranged to contain fuelcharacterized in that the fuel tank (30) comprises a fuel filter housing (34) surroundingat least a portion of the fuel filter device (12) according to any one of claims 1 to 5 inside the tank (30). Fuel tank according to claim 6, characterized in that the fuel filter housing (34) isarranged to contain the support body and the filter element (43) and the portion oftheventing tube (44) extending between the first and second end portions (41; 42) of thesupport body, and wherein the fuel filter housing (34) comprises a first opening (38) through which the end portion (47) ofthe venting tube (44) extends. Fuel tank (30) according to claim 7, characterized in that the fuel filter housing (34) isarranged below the highest nominal fuel level (37) of the fuel tank and at least a part of the solid venting tube portion (47) is arranged above the fuel level (37). Fuel tank (30) according to any of claims 6-8, characterized in that fuel tank housing(32) comprises attachment means (35; 45) to connect the fuel filter device (12) to thefuel tank housing (32), wherein at least a portion of the attaching means are located outside the fuel tank housing (32). Fuel tank (30) according to any of claims 6-9, characterized in that the fuel filterhousing (34) comprises an opening for a fuel conduit through which fuel is fed into the filter device (12). Fuel tank (30) according to any of claims 6 to 10, characterized in that the fuel tank (30) further comprises at least one fuel pump (22; 26). Fuel tank according to any of claims 6 to 11, characterized in that the fuel tank comprises venting means (33) to deaerate the tank. 1

3. 1

4. 18A fuel system (4) for an internal combustion engine (2), the fuel system comprising amain fuel tank (20), a technology tank (30), a first fuel conduit (24) connecting themain fuel tank and the technology tank, a first fuel pump (22) arranged to feed fuelfrom the main fuel tank (20) to the technology tank (30) through the first fuel conduit(24), and a fuel filter device (12) arranged downstream of the first fuel pump (22),characterized in that the technology tank (30) comprises a filter housing (34) arrangedto surround at least a portion of the fuel filter device (12) comprising a support bodycarrying a filter element (43), the support body comprising a first end portion (41) anda second end portion (42) and a hollow cylindrical central tube (31) extending betweenthe first and second end portions (41, 42), the filter element (43) surrounding thecentral tube (31) comprising apertures and the fuel filter device (12) further comprisinga hollow cylindrical venting tube (44) arranged in the hollow central tube (31), theventing tube (31) extending between the first and second end portions (41, 42) andoutside beyond the first end portion (41) in a longitudinal direction (L) of the fuel filterdevice (12), and wherein a wall of the venting tube (44) comprises apertures (48a; 49a)along the length of the venting tube (44) extending between the first and second endportions (41, 42), and wherein the wall portion (47) of the venting tube extendingbeyond the first end portion (41) is solid, and wherein the first fuel pump (22) isarranged to feed fuel through the fuel filter device (12) via the first fuel conduit (24)and an opening in the fuel filter housing (34) through the filter element (43) andupwards through the solid wall portion (47) of the venting tube (44), whereby the fuel filter device (12) is deaerated or vented. Vehicle (1), characterized in that it comprises the fuel filter of claims 1-5, a fuel tank of claims 6-12 or a fuel system of claim 13.