Title of Invention

A FEED UNIT FOR FEEDING FUEL OUT OF A FUEL TANK OF A MOTOR VEHICLE

Abstract

The invention relates to a feed unit (2) for feeding fuel one of a fuel tank (1) of a motor vehicle having a baffle (4) which has first chamber (7) for collecting fuel having a fuel pump (5) for sucking up fuel and having a fuel-pump suction opening (6) arranged in the vicinity of the bottom of the first chamber (7) of the baffle (4). A second chamber (13) is connected to the first chamber (7) via a valve (14), and in that the valve (14) is a throttle valve with the volumetric flow of fuel that in restricted by the valve (14) being smaller than the volumetric flow fed by the fuel pump (S).

Full Text

FIELD OF THE INVENTION The invention relates to a feed unit for feeding fuel out of a fuel tank of « motor vehicle, having a baffle which has a first chamber for collecting fuel having a fuel pump for sucking up fuel and having a fuel-pump suction opening arranged in the vicinity of the bottom of the first chamber of the baffle. BACKGROUND OF THE INVENTION Feed units of this type are frequently used in motor vehicles today and are known in pratice. The chamber of the baffle generally has a bottom valve and is filled with fuel via a suction jet pump driven by the fuel pump. In addition the baffle is arranged in a bottom region of the fuel tank so that fuel can flow out of the fuel tank into the baffle via the bottom valve. The filling of the baffle via the suction jet pump ensures that even of there is a very low fuel level in the fuel tank the baffle is sufficiently filled with fuel. When the fuel tank is empty the baffle is also emptied as a result of which the fuel-pump suction opening emerges out of the fuel. Before the fuel pump can feed fuel again sufficient fuel has to be poured into the fuel tank* for example by means of a terrycan, for fuel to penetrate into the baffle. Only when the fuel-pump suction opening is resubmerged into the fuel can the fuel pump feed fuel. However a minimum quantity of fuel is required for this. It is already been thought to arrange the baffle directly below a filler neck of the fuel tank. In this case the baffle is filled at the beginning when the fuel is poured in. However this arrangement of the baffle is frequently impossible in the case of fuel tanks nowadays* which are generally very shallow and angled. US 6606980 discloses a fuel tank for a motor vehicle is provided with a reservoir* which is accessible through a closable opering in the wall of the fuel tank. In order to be able to select the size of the reservoir independently of the size of the opening, the reservoir comprises at least two modules which can be connected to each other and which are assembled within the tank to form the reservoir. At least one module of the reservoir can already be inserted into the tank when producing the tank. Additional modules can be inserted into the finished tank through the opening in the wall of the tank. It is 2A. also possible for all modules forming the reservoir to be subsequently inserted into the tank through the opening in the wall of the tank. US 4354521 describes a device in a fuel tank for motor vehicles which if the fuel level is low when driving on an inclined surface retains a required amount of fuel around the fuel line opening to prevent air intake. Around a container on the tank bottom* into which the fuel line opens* is a larger container and the two containers have inlets for fuel from the surrounding tank. One container has the inlet in its front side wall and the other container in its rear side wall as reviews in the longitudinal direction of the vehicle. The invention is based on the problem of designing a feed unit of the type mentioned at the beginning in such a manner that alter the first chamber of the baffle is emptied the fuel- pump suction opening is reliably covered with fuel. 2B. SUMMARY OF THE INVENTION Tit is problem is solved according to the invention by a second chamber being connected to the first chamber via a valve* and by the valve being a throttle valve with the volumetric flow of fuel that is restricted by the valve being smaller than the volumetric flow fed by the fuel pump. This design makes it possible for the first chamber to be initially emptied, as in the case of the known feed unit after the fuel tank has been emptied. Over a period of time which im dependent an the throttling action of the valve, fuel flows out of the second chamber into the first chamber and covers the fuel- pump auction opening. Feeding of the fuel pump is ensured by the invention. If at the same time a small quantity of fuel is put into the fuel tank for example via the jerrycan, the feed unit according to the invention is capable of feeding the topped-up fuel. The feed unit according to the invention has a particularly low outlay on installation if the second chamber is manufactured integrally with the baffle. The second chamber could be arranged, for example, above the first chamber. However, according to another advantageous development of the invention, a filling of the second chamber can be ensured in a simple manner if the chambers are arranged at the same height. During the operation of the feed unit according to the invention, the second chamber, like the first chamber, can therefore be filled with fuel. The feed unit according to the invention has a particularly low structural outlay if the valve is arranged in a common wall of the first chamber and of the second chamber. Acccrding to another advantageous development of the invention, the baffle turns out to be particularly compact if the second chamber is designed as an annular chamber surrounding the first chamber. By this means, the feed unit according to the invention can be arranged in a simple manner even in particularly shallow and angled fuel tanks. According to another advantageous development of the invention, a reliable filling of the second chamber with fuel can be ensured in a simple manner if the second chamber is arranged within the baffle and the common wall between the first chamber and the second chamber is lower than an outer wall of the baffle. Fuel can thus flow from the first chamber into the second chamber. According to another advantageous development of the invention the throttling of the fuel flowing from the second chamber into the first chamber requires a particularly low structural outlay if the valve is designed as an opening with a designated cross section. During the emptying of the first chamber the valve has to throttle an over flow of fuel out of the second chamber into the first chamber so that when the fuel tank is empty sufficient fuel remains in the second chamber. According to an advantageous development of the invention sufficient throttling of the overflowing fuel can be achieved in a simple manner with customary volumes of known baffles if the valve throttles the volumetric flow which flows from the second chamber into the first chamber in such a manner that the level is equalized in three to five minutes after the fuel pump has stopped. According to another advantageous development of the invention a sufficient fuel level in the first chamber after the fuel tank has been emptied can be reliably ensured if the second chamber has a volume of approximately 10 - 20% of the baffle volume. The invention permits numerous embodiments. To further clarify its basic principle* one of these is illustrated in the accompanying drawings and is described below. In the accompanying drawings: fig. 1 shows schematically a longitudinal section through a fuel tank with a feed unit according to the invention arranged therein, fig. 2 shows the feed unit according to the invention from figure 1 after the fuel tank has been topped up with a small quantity of fuel. Figure 1 shows schematically a longitudinal section through a fuel tank 1 for a motor vehicle, having a feec unit 2 which is arranged in the bottom region and is intended for feeding fuel out of the fuel tank 1 to an internal combustion engine 3 of the motor vehicle. The feed unit 2 has a baffle 4 with an electrically operated fuel pump 5 arranged therein. A suction opening 6 of the fuel pump 5 is arranged in the bottom region of a first chamber 7 of the baffle 4. A forward flow line 8 leads from the fuel pump 5 to the internal combustion engine 3. Furthermore, a suction jet pump 9 is arranged in the bottom region and is supplied with fuel as the working fluid via a fuel line 10 branching off from the forward flow line 8. The suction jet pump 9 sucks up fuel via a bottom valve 11 arranged on the baffle 4, and conveys the fuel into the first chamber 7 of the baffle 4. A wall. 12 for separating off the first chamber 7 from a second chamber 13 is arranged in the baffle 4. The wall 12 has a valve 14 which is designed as a throttle valve and permits fuel to flow through into the first chamber 7. The wall 12 separating the chambers 7, 13 from each other is lower than an outer wall 15 of the baffle 4. This ensures that, during normal operation of the feed unit 2, the second chamber 13 is at all times filled with fuel. During the operation of the feed unit 2, the internal combustion engine 3 is supplied with fuel and at the same time the baffle 4 is filled with fuel, via the suction jet pump 9. The filling of the baffle 4 with fuel is ensured as long as the fuel level in the fuel tank 1 reaches as far as the bottom valve 11. If the fuel level drops below the bottom valve 11, the feed unit 2 supplies the internal combustion engine 3 with fuel until the first chamber 7 of the baffle 4 is empty, as illustrated in figure 1. The internal combustion engine 3 therefore does not obtain any fuel and the fuel pump stops. A topping-up of the fuel tank 1 with fuel takes place generally with a very small quantity. This quantity is generally sufficient in order to enable the level in the fuel tank 1 to rise again as far as the bottom valve; 11. Since, however, the suction opening 6 of the feed unit 2 in the baffle 4 is arranged higher than the level in the fuel tank 1, the feed unit 2 can only suck up fuel again and the suction jet pump 9 can be supplied with fuel as the working fluid if the fuel level in the first chamber 7 is higher than the suction opening 6 of the feed unit 2. After the first chamber 7 has been emptied, fuel present in the second chamber 13 flows via the valve 14, which is designed as a throttle valve, slowly into the first chamber 7, as illustrated in figure 2. The throttling action is configured in such a manner that the hydraulic equalizing operation lasts for three to five minutes. The flowing of the fuel through, into the first chamber 7 causes the suction opening 6 to again be situated below the fuel level. The feed unit 2 can therefore supply the internal combustion engine 3 and the suction jet pump 9 again with fuel. The throttling of the volumetric flow, which is guided 5 into the first chamber 4, by the valve 14, which is designed as a throttle valve, is dimensioned in such a manner that the fuel flows more slowly into the first chamber 7 than the feed unit 2 feeds fuel to the internal combustion engine 3. WE CLAIM: 1. A feed unit (2) for faading fuel out of a fuel tank (1) of a motor vahicle having a baffla (4) which has a first chtmbar (7) for collacting fuel having a fuel pump (5) for sucking up fuel and having a fuel—pump suction opaning (4) arrangad in tha vicinity of tha bottom of tha first chamber (7) of the baffla (4), charactarizad in that a sacond chubtr (13) is connected to tha first chambar (7) via a valva (14), and in that the valve (14) is a throttla valva with tha volumatric flow of fuel that is restrictad by tha valva (14) baing smallar than tha volumatric flow fad by tha fuel pump (5). 2. Tha faad unit as claimed in claim 1 wharain tha sacond chambar (13) is manufactured intagrally with tha baffla (4). 3. Tha faad unit as claimad in claim 1 or 2 wharain tha chambers (7, 13) are arrangad at tha same height. 4. The feed unit as claimed in at least one of the preceding claims, wherein the valve (14) is arranged in a common wall (12) of the first chamber (7) and of the second chamber (13). 5. The feed unit as claimed in at least one of the preceding claims, wherein the second chamber (13) is designed as an annular chamber surrounding the first chamber (7). 6. The fuel feed unit as claimed in at least one of the preceding claims wherein the second chamber (13) is arranged within the baffle (4) and the common wall (12) between the first chamber (7) and the second chamber (13) is lower than an outer wall (15) of the baffle (4). 7. The feed unit as claimed in at least one of the preceding claims, wherein the valve (14) is designed as an opening with a designated cross section. 8. The feed unit as claimed in at least one of the proceding claims wherein tha valva (14) throttles the volumet- ric flow which flows from tha second chamber (13) into the first chamber (7), in such a manner that tha level is equalized in three to five minutes after the fuel pump (5) has stopped. 9. The feed unit as claimed in at least one of the preceding claims* wherein the second chamber (13) has a volume of approximately 10-20X of the baffle volume. The invention relates to a feed unit (2) for feeding fuel one of a fuel tank (1) of a motor vehicle having a baffle (4) which has first chamber (7) for collecting fuel having a fuel pump (5) for sucking up fuel and having a fuel-pump suction opening (6) arranged in the vicinity of the bottom of the first chamber (7) of the baffle (4). A second chamber (13) is connected to the first chamber (7) via a valve (14), and in that the valve (14) is a throttle valve with the volumetric flow of fuel that in restricted by the valve (14) being smaller than the volumetric flow fed by the fuel pump (S).

Documents:

556-KOLNP-2005-ASSIGNMENT.pdf

556-KOLNP-2005-CORRESPONDENCE 1.1.pdf

556-KOLNP-2005-CORRESPONDENCE 1.2.pdf

556-KOLNP-2005-FORM 27.pdf

556-kolnp-2005-granted-abstract.pdf

556-kolnp-2005-granted-claims.pdf

556-kolnp-2005-granted-correspondence.pdf

556-kolnp-2005-granted-description (complete).pdf

556-kolnp-2005-granted-drawings.pdf

556-kolnp-2005-granted-examination report.pdf

556-kolnp-2005-granted-form 1.pdf

556-kolnp-2005-granted-form 18.pdf

556-kolnp-2005-granted-form 2.pdf

556-kolnp-2005-granted-form 3.pdf

556-kolnp-2005-granted-form 5.pdf

556-kolnp-2005-granted-gpa.pdf

556-kolnp-2005-granted-reply to examination report.pdf

556-kolnp-2005-granted-specification.pdf

556-kolnp-2005-granted-translated copy of priority document.pdf