WO2014204379A1

WO2014204379A1 - Fuel filtering device

Info

Publication number: WO2014204379A1
Application number: PCT/SE2014/050698
Authority: WO
Inventors: Dan CEDFORS; Anders Jonsson
Original assignee: Scania Cv Ab
Priority date: 2013-06-18
Filing date: 2014-06-10
Publication date: 2014-12-24
Also published as: SE1350740A1; SE537324C2

Abstract

A device for filtering of liquid fuel on its way between a fuel tank and a combustion engine comprises a filter house (1 0) with a fil- tering chamber (13). A filter cassette (14) is received in the filtering chamber. When, at filter replacement, the filter cassette is lifted out of the filter house, a draining opening is revealed at the bottom of the filter house, and fuel existing in the filtering cham¬ ber is led by way of gravitation down into a container (24) with an inlet at a lower level than the draining opening.

Description

Fuel filtering device

TECH N ICAL FI ELD OF TH E I NVENTION

The invention pertains to a device for filtering of liquid fuel according to the preamble of the enclosed claim 1 . Thus the invention is not limited to any specific type of combustion engine or fuel , and diesel and ethanol may be mentioned as a couple of non-exhaustive examples of fuel . The invention also pertains to filtering of fuel to combustion engines designed for all types of use, such as in industrial applications, crushing ma- chines and various types of motor vehicles, even though the invention is particularly applicable to wheeled motor vehicles, especially commercial vehicles, such as trucks and buses, and will for this reason sometimes be discussed in this use for purposes of elucidating, but not limiting, the invention.

One said filtering device is arranged in a low pressure part of a system for supply of fuel from a fuel tank to a combustion engine, to catch dirt particles in the fuel and protect equipment for injection of fuel into the combustion engine, arranged in the system's high pressure part. Therein the present invention pertains to fuel filtration devices for a subsequent high-pressure part with any appearance. A device of the type defined above is said to have a "top- mounted filter", since the filter element is replaced by lifting the filter cassette containing the same upwards out of the filter house. At such a filter replacement, the draining opening at the bottom of the base part of the filter house is revealed , and in prior art filtering devices of this type, the dirty fuel then existing in the filtering chamber of the filter house is led back to said fuel tank with the help of gravitation , in order to protect said injection equipment downstream of the filter house during the filter re- placement and any additional service.

BACKG ROUN D TECHNOLOGY

US 2002/0020661 A1 shows a filtering device of the type stated above.

Often , however, said fuel tank is located at a relatively long distance from the filter house, which is mostly located in direct connection with the combustion engine, and the conduit from the fil- ter house back to the fuel tank then becomes long and may be placed both high and low, in which case gravitation is not sufficient either for draining or transporting the unfiltered dirty fuel from the filter house. (Air bubbles in the conduit may also make the transport slower) . This is for example the case in the above mentioned motor vehicles in the form of trucks and buses. The unfiltered dirty fuel will then remain in the filter house, and when a new filter cassette is inserted there is a risk that it may end up on the "clean" side of the filter element and later, at upstart after service, it may reach said injection system with a risk of causing damage to this equipment. SUMMARY OF TH E I NVENTION

The objective of the present invention is to provide a device of the type defined above, which shows, in relation to such prior art devices, an improved solution of the above mentioned problem at least in some respect.

This objective is achieved according to the invention by providing a device of the type with the features listed in the characterising portion of claim 1 .

By arranging a said container for collection of fuel existing in the filtering chamber at the filter replacement (lifting up the filter cassette) , with its inlet at a lower level than the filter house's draining opening, the fuel existing in the filtering chamber may be emptied efficiently into the container via gravitation, so that no dirty fuel remains in the filtering chamber and risks to end up on the "clean" side of the filter element when a new filter cas- sette is inserted. Thus, the equipment in the fuel injection system in the fuel supply path from the fuel tank to the combustion engine after the filtering device is protected efficiently. The container may comfortably be arranged so that the fuel does not get stuck anywhere when led there, as was previously the case when the fuel was led back to the fuel tank.

According to one embodiment of the invention the conduit element for connection of the draining opening with the container's inlet, the draining opening and the location of the container in re- lation to the filter house are adapted to empty the filtering cham- ber of fuel via gravitation, when the filter cassette is lifted up from the base part, within five seconds or within three seconds from the time when said lifting started . Thus all dirty fuel in the filtering chamber will be efficiently "sucked out" of the filtering chamber, which is thus emptied completely before there is a chance of inserting a new filter cassette in the filter house even for the fastest of service technicians.

According to another embodiment of the invention, the container is arranged with said inlet therein at a distance from the draining opening of 0-0.5 metres or 0-0.3 metres. By arranging the container at such a short distance from the filter house's draining opening a fast and reliable total emptying of the filtering chamber of fuel may occur when the filter cassette is lifted up.

According to another embodiment of the invention, the container is arranged straight under the base part, and a bottom of the base part may then advantageously form an upper limit of the container, and the draining opening opens into the container's inlet. Thus, a very fast and efficient emptying of the filtering chamber of dirty fuel may occur when the filter cassette is lifted .

According to another embodiment of the invention, the closing element comprises a covering part, adapted to be fixed to the lower side of the filter cassette.

According to another embodiment of the invention, the container has an outlet for at least partial emptying thereof of fuel received from the filter house. Since the container has such an outlet, it may be emptied of fuel without having to be lifted away from its place in proximity to the filter house.

According to a further development of this embodiment, the con- tainer's outlet is connected to a conduit, connected with the inlet of the base part of the filter house, for emptying of fuel from the container into this conduit. This means that the fuel which has been "du mped" in the container will be fed, jointly with other fuel , from the fuel tank to the filter house for filtration by the newly in- serted cassette at continued operation of the combustion engine. Thus, a check valve may be arranged in the container's outlet to prevent fuel from being fed from said conduit into the container.

According to another embodiment of the invention , the con- tainer's outlet is connected with a conduit for at least partial emptying of fuel from the container into a vessel . The fuel in the separate vessel is then taken care of in a suitable manner and the container is ready, after it is emptied, to fulfil its function at the next filter replacement.

According to another embodiment of the invention , the container's outlet is connected to a conduit for recirculation of fuel from the container to a said fuel tank. When the dirty fuel has reached the container it is uncritical whether the recirculation of fuel to the fuel tank is slow and subject to disruptions.

The invention also pertains to a device for supply of fuel from a fuel tank to a high pressure part of a system for fuel injection into a combustion engine, comprising a filtering device according to the invention , arranged in a conduit in a low pressure part be- tween the fuel tank and the combustion engine. The advantages of such a device for fuel supply are clear from the discussion above of the device according to the invention and the embodiments thereof .

The invention also pertains to a motor vehicle which has a device according to the invention for fuel filtration .

Other advantages and advantageous features of the invention are set out in the description below.

BRI EF DESCRI PTION OF TH E DRAWI NGS

Below are descriptions of example embodiments of the invention with reference to the enclosed drawings, in which :

Fig. 1 is a very schematic view illustrating the structure of a device for fuel supply from a fuel tank to a combustion engine, comprising a filtering device according to the invention,

Fig. 2 illustrates schematically the structure of a filtering device according to a first embodiment of the invention in its functional mode, Fig. 3 shows the device according to Fig. 2 at filter replacement, and

Fig. 4 is a view corresponding to Fig. 2 of a filtering device according to a second embodiment of the invention . DETAI LED DESCRI PTION OF EMBODI M ENTS ACCORD I NG TO TH E I NVENTION

Fig 1 shows, in a very simplified manner, a system for fuel injec- tion into a combustion engine equipped with a device according to the invention, for supply of fuel from a fuel tank 1 , via a pump 2 and a filter house 3, in a fuel filtering device in a low pressure part L to a high pressure part H , which begins with a high pressure pump 4, pu mping fuel with a high pressure to a fuel accumu- lator 5 with nozzles 6 for injection of the fuel into the cylinders of a combustion engine 7, arranged in a motor vehicle identified with the digit 8. It shows how fuel may be led via a conduit 9 to the fuel tank 1 , e.g . from the filter house 3. In practice, a system according to Fig. 1 has significantly more components than dis- played here, and it may have widely differing appearances, since the invention pertains to devices for filtering of liquid fuel on its way between a fuel tank and a combustion engine in general .

Fig. 2 illustrates schematically a device according to a first em- bodiment of the invention, comprising a filter house 1 0 with a base part 1 1 and a removable lid 1 2 fixed at the top at the base part. The base part and the lid delimit a filtering chamber 1 3 for receipt of fuel to be filtered. A replaceable filter cassette 1 4 with a filter element 1 5 is releasably mountable in the filtering cham- ber.

An inlet 1 6 is arranged at the upper part of the base part for supply of fuel from the fuel tank to the filtering chamber via a first conduit 1 7. An outlet 1 8 is arranged in the lower part of the base part, for feeding of fuel that has passed through the filter element from the filter chamber to a second conduit 1 9, which leads clean filtered fuel along to the combustion engine's injection system. Thus, the fuel passing the filter element 1 5 reaches, in a conventional manner, a pipe 20 with holes in its jacket surface in the fil- tering chamber for penetration into this and being led to said second conduit 1 9.

A draining opening 21 is arranged at the bottom 22 of the base part for emptying the filtering chamber of fuel . Elements in the form of a covering part 23, fixed to the lower side of the filter cassette, are designed to close the draining opening 21 in a functional position of the device according to Fig .2,

The characterising features of the invention shall now be de- scribed with reference to Figs. 2 and 3. The device according to the invention comprises a container 24 arranged straight below the filter house 1 0, thus a type of bottom cavity in the filter house, with an inner volu me with a capacity to receive the amount of fuel which the filtering chamber may contain. The con- tainer 24 has an inlet 25 at the top, which is directly connected to the filter house's draining opening 21 . This means, that when the filter cassette 1 4 is lifted out of the filter house when the filter is replaced, as displayed In Fig . 3, then the covering part 23 will reveal the draining opening 21 , and fuel existing in the filtering chamber will be emptied into the container 24 with the help of gravitation. The dirty, emptied fuel is identified with the digit 26 in Fig . 3. It is displayed how the pipe 20 for purified fuel is extended through the container via a part 27, wherein this part has a tight jacket surface. The container 24 has an outlet 28 for emptying of fuel received from the filter house into said first conduit 1 7, for later supply of the same to the filter house at the combustion engine's continued operation following a filter replacement. A check valve 29 is ar- ranged to prevent fuel from being fed from the first conduit into the container.

Fig. 4 shows a device according to a second embodiment of the invention , and the parts which are in the device displayed at Figs. 2 and 3 are equipped with the same references and will not be described further here. This device differs from the one according to the first embodiment, since the container 24 is arranged at a small distance, such as for example two decimetres, from the filter house 1 0, but with its inlet 25 at a lower level than the filter house's draining opening 21 . Accordingly, the container is connected with the filter house's draining opening via a short conduit 30. Here, two alternative ways of emptying the container are also illustrated , wherein the first is by connecting an outlet of the container with a conduit 31 for at least partial emptying of the container of fuel into a vessel 32. The other alternative is to connect an outlet of the container with a conduit 9' for recirculation of fuel from the container to the fuel tank.

The invention is obviously not li mited in any way to the embodi- ments described above, but nu merous possible modifications thereof should be obvious to a person skilled in the area, without departing from the framework of the invention as defined by the appended claims. Even if the description above makes this clear, it is pointed out that "conduit elements for connection of the draining opening with said inlet into the container" in this thesis shall be interpreted as though the draining opening is connected with the inlet in such a manner that something (here the fuel) may be led between these. However, a physical line is not necessary - instead the draining opening may be directly connected to the inlet or even form the inlet to the container.

Claims

Device for filtering of liquid fuel on its way between a fuel tank ( 1 ) and a combustion engine (7) , which device comprises:

• a filter house (1 0) with a base part (1 1 ) and a releasable lid fixed at the top of the base part (1 4) ,

• a filtering chamber (1 3) deli mited by the base part and the lid for receipt of fuel to be filtered,

• a replaceable filter cassette (1 4) equipped with a filter element (1 5) which is releasably mountable in the filtering chamber,

• an inlet (1 6) in the top part of the base part for supply of fuel to the filtering chamber,

• an outlet (1 8) in the lower part of the base part (1 1 ) for feeding out of fuel having passed through the filter element from the filtering chamber (1 3) ,

• a draining opening (21 ) at the bottom (22) of the base part for emptying the filtering chamber of fuel ,

• elements (23) designed , in a functional mode of the device, to close the draining opening, and

• means designed to functionally connect said closing element with the filter cassette and the lid, so that a removal of said lid and lifting out of the filter cassette from the base part for replacement of the filter cassette entails an impact on the closing element (23) to transition to a position revealing the draining opening (21 ) , for removal of fuel existing in the filtering chamber (1 3) from the base part, characterised in that the device comprises a container (24) with an inner volu me with an ability to receive the amount of fuel which the filtering chamber is able to hold, and which is adapted to be arranged with an inlet (25) therein at a lower level than the draining opening (21 ) , and in that the device comprises conduit elements (30) for connection of the draining opening with said inlet of the container, for emptying of fuel existing in the filtering chamber ( 1 3) into the container (24) by way of gravitation , when the filter cassette (1 4) is lifted out of the base part.

Device according to claim 1 , characterised in that said conduit elements (30) , the draining opening (21 ) and the localisation of the container (24) in relation to the filter house (1 0) are adapted to, when the filter cassette is lifted out of the base part by way of gravitation, empty the filtering chamber (1 3) of fuel within five seconds or within three seconds from the point in time when said lifting started.

Device according to claim 1 or 2, characterised in that the container (24) is arranged with said inlet (25) therein at a distance from the draining opening (21 ) of 0-0.5 meters or 0- 0.3 metres.

Device according to any of the previous claims, characterised in that the container (24) is arranged straight under the base part (1 1 ) .

5. Device according to claim 4, characterised in that a bottom (22) of the base part (1 1 ) forms the upper limit of the con- tainer (24) , and said draining opening (21 ) opens into the container's inlet (25) .

6. Device according to any of the previous claims, characterised in that the closing element comprises a covering part (23) adapted to be fixed to the lower side of said filter cassette (1 4) .

7. Device according to any of the previous claims, characterised in that the container (24) has an outlet (28) for at least partial emptying thereof of fuel received from the filter house (1 0) .

8. Device according to claim 7, characterised in that the container's outlet (28) is connected with a conduit ( 1 7) , connected with said inlet (1 6) of the filter house's base part (1 1 ,) for emptying of fuel from the container into this conduit.

9. Device according to claim 8, characterised in that a check valve (29) is arranged in the container's outlet (28) , to prevent fuel from being fed from said conduit (1 7) into the container (24) .

1 0. Device according to claim 7, characterised in that the container's outlet is connected with a conduit (31 ) for at least partial emptying of the container (24) of fuel into a vessel (32) .

1 . Device according to claim 1 0, characterised in that the container's outlet is connected with a conduit (9') for recirculation of fuel from the container (24) to a said fuel tank (1 ) . 2. Device for supply of fuel from a fuel tank (1 ) to a high pressure part (H) of a system , for fuel injection into a combustion engine (7) , characterised in that it comprises a filtering device according to any of the previous claims, arranged in a low pressure part (L) in a conduit between the fuel tank and the combustion engine. 3. Motor vehicle, especially a wheeled motor vehicle, in particular a truck or bus, characterised in that it has a device for filtering of fuel according to any of claims 1 - 1 1 .