Fuel delivery system for a vehicle

Abstract

A fuel delivery system for a vehicle is proposed, comprising at least one main fuel pump for supplying fuel to an internal combustion engine by providing a fuel pressure, at least one auxiliary fuel pump (12) uncoupled from the main fuel pump (10) and for supplying fuel injection to at least one suction injection pump (14, 16) as required and for setting the pressure of the fuel injection before the nozzle of the suction injection pump (14, 16) independently of the main fuel pump (10), and at least one suction injection pump (14, 16) for delivering fuel from one region (4b) of a fuel tank (4) to another region (4a) of the fuel tank (4).

Description

[0001] The present invention relates to a fuel delivery system for a vehicle, a fuel tank having such a fuel delivery system, and a vehicle having such a fuel tank.

[0002] A suction injection pump installed in the vehicle's fuel supply system is used to transfer fuel from one area of ​​the fuel tank to another area of ​​the fuel tank, where an electric fuel pump is located. The suction injection pump is also used to remove condensed fuel from the ventilation system and supply the fuel to the fuel pump.

[0003] According to the prior art, the suction injection pump is supplied with fuel injection through a fuel pump to achieve the purpose of pump operation, which is mainly used to supply fuel to an internal combustion engine.

[0004] In the low to medium load range of an internal combustion engine, depending on the number and design of the suction injection pump and the design of the fuel pump, 50% to 90% of the energy supplied to the fuel pump is used for the fuel supply to the suction injection pump. This requires a correspondingly larger fuel pump and also results in a correspondingly higher energy consumption.

[0005] Furthermore, fuel vapor is formed in principle at the outlet of this suction injection pump and is added to the evaporating fuel in the fuel tank due to the temperature, thus contributing to the formation of fuel vapor in the fuel tank. Especially in cases with complex tank geometries requiring multiple suction injection pumps, a considerable amount of fuel vapor is formed by the suction injection pumps, resulting in an overall increase in fuel vapor formation in the fuel tank. In principle, the energy and evaporation problems can be solved by suction injection pumps that can be mechanically or electrically activated and deactivated, as is known according to existing technology. However, this leads to a more complex and therefore more expensive system.

[0006] Therefore, the purpose of this invention is to help save energy with respect to the type of fuel pump.

[0007] Another objective of this invention is to reduce the formation of fuel vapor in the fuel tank.

[0008] The objective is achieved through embodiments of the present invention, which disclose a fuel delivery system for vehicles.

[0009] A fuel delivery system is proposed, which has the following characteristics:

[0010] At least one main fuel pump is provided for supplying fuel to the internal combustion engine by providing fuel pressure.

[0011] At least one auxiliary fuel pump, disconnected from the main fuel pump, is used to supply fuel injection to at least one suction injection pump as needed and to set the pressure of the fuel injection before the nozzle (also referred to as the "propellant nozzle") of the suction injection pump independently of the main fuel pump.

[0012] At least one suction injection pump is used to transfer fuel from one area of ​​the fuel tank to another area of ​​the fuel tank or to a fuel delivery unit.

[0013] The separation or disconnection of the fuel supply to the internal combustion engine from the fuel or propellant flow supply to the at least one suction injection pump results in significant energy savings because both the main fuel pump and the auxiliary fuel pump can be more advantageously designed or sized according to their application. This also improves the efficiency of such a system compared to systems according to the prior art.

[0014] Furthermore, the fuel injection pressure or propellant pressure before the nozzles or propellant nozzles of the suction injection pump can be set, and in this case, the fuel injection pressure or propellant pressure can be reduced as needed, independently of the main fuel pump. This also reduces fuel vapor formation at the suction injection pump outlet, which occurs because the fuel or propellant flow at the suction injection pump outlet expands from a relatively high pressure level to a relatively low pressure level. As a result, fuel vapor formation is also reduced overall within the fuel tank. This, in turn, allows for the use of relatively small fuel vapor storage or activated carbon storage in the tank ventilation system, thus contributing to cost savings.

[0015] The disconnection or decoupling advantageously allows at least one main fuel pump to have its power consumption reduced to an absolute minimum when needed, that is, during phases when the internal combustion engine requires no fuel or at least almost no fuel, particularly when the auxiliary fuel pump ensures the supply of fuel or propellant to at least one suction injection pump. To illustrate this, one could mention, for example, a vehicle descending in a parking garage, which is associated with a corresponding overspeed fuel interruption of the internal combustion engine.

[0016] Compared to systems known according to the prior art (which allow mechanical or electrical activation and deactivation of the suction jet pump to address energy issues and, in principle, fuel vapor formation), the proposed system not only improves system robustness but also extends the operating range of the suction jet pump due to the settableness of the fuel or propellant flow rate, which is independent of the main pump.

[0017] Therefore, the proposed system may include two or more fuel pumps, wherein preferably, the at least one main fuel pump is not assigned to a suction injection pump, or is assigned to a suction injection pump with a low fuel or propellant flow rate. This can facilitate maximum energy savings. The suction injection pumps provided in the system are assigned to at least one or more auxiliary fuel pumps. In this respect, the assignment of the suction injection pumps is asymmetrical. The assignment of the suction injection pumps may also be asymmetrical relative to multiple auxiliary fuel pumps.

[0018] According to one aspect of the invention, a check valve is provided downstream of the auxiliary fuel pump, which disconnects the hydraulic delivery circuit to which the auxiliary fuel pump belongs from the delivery path of the main fuel pump. Through the check valve, the auxiliary fuel pump can be connected in a manner that supports the main fuel pump, so as to advantageously connect, for example, within the upper load range of the internal combustion engine, to directly facilitate the supply of fuel to it.

[0019] According to another aspect of the invention, it is advantageously possible that the main fuel pump is sized to be less powerful than the auxiliary fuel pump and designed for a portion of the load range of the internal combustion engine (e.g., the low to medium load range), wherein, at the full load range of the internal combustion engine (i.e., at the upper load range up to the full load), a more powerful auxiliary fuel pump can be connected to the delivery path via the check valve to support the main fuel pump. This design contributes to the energy savings and also complements the aforementioned asymmetry.

[0020] Furthermore, it is proposed that a first pipeline connection point is provided downstream of the auxiliary fuel pump and before the check valve, from which at least one pipeline extends to the at least one suction injection pump. From the first pipeline connection point, for example, a first pipeline can be extended to a first suction injection pump and a second pipeline can be extended to a second suction injection pump.

[0021] The proposed auxiliary fuel pump supports the main fuel pump in supplying fuel to the internal combustion engine, wherein a third line extends from the first line connection point to a second line connection point, which is provided downstream of the main fuel pump and from which a line (as part of the delivery path) extends for the purpose of supplying fuel to the internal combustion engine.

[0022] In this configuration, the at least one suction injection pump may be located in or on the vortex tank of the fuel delivery unit. For example, the first suction injection pump may be located in or on the vortex tank of the fuel delivery unit in a first region of the fuel tank, while the second suction injection pump may be located in a second region of the fuel tank.

[0023] Here, the at least one auxiliary fuel pump can be arranged in the area of ​​the main fuel pump, wherein, depending on the configuration of the fuel delivery unit, the auxiliary fuel pump can be arranged inside or outside the vortex tank of the fuel delivery unit, wherein the main fuel pump is preferably arranged in the vortex tank.

[0024] In principle, the system proposed in the context of this disclosure is independent of box geometry. In this respect, the proposed system is applicable to both simple and complex box geometries.

[0025] According to a further aspect of the invention, the setting based on the required fuel injection pressure before the nozzle of the suction injection pump is achieved by means of control or regulation of the auxiliary fuel pump. This control or regulation can be achieved by using at least one characteristic profile, a characteristic curve, and / or a fixed value, taking into account the operating point of the suction injection pump. Here, the control or regulation can be further based on current; that is, the supply current or a current-related reference variable (e.g., pressure or volumetric flow rate) can be used as the control or regulation variable.

[0026] A fuel tank for a vehicle having a fuel delivery system of the type described above is also proposed, as well as a vehicle having such a fuel tank.

[0027] The invention will now be discussed in detail with reference to a single accompanying drawing. Further advantageous improvements to the invention will become apparent from the following description of embodiments thereof. For this purpose, the drawings are as follows:

[0028] Figure 1 A schematic diagram of the proposed fuel delivery system is shown.

[0029] Fuel delivery system 2 includes a saddle-shaped box 4, which has a first (or Figure 1 (Middle left) Box area 4a and the second (or Figure 1 (Right side of the middle box area 4b)

[0030] Fuel delivery unit 6 is arranged in the left tank area 4a and includes a vortex tank 8, which houses both the main fuel pump 10 and the auxiliary fuel pump 12. In this case, each of the two fuel pumps 10, 12 includes an electric motor and a pump stage driven by that electric motor. Here, schematically, for simplicity, the filters 9, 11 assigned to the two fuel pumps 10, 12 represent, in their respective cases, a pre-filter and a fine filter for filtering the delivered fuel. Also arranged in or on the vortex tank 8 in the left tank area 4a is a first suction injection pump 14, into which a propellant nozzle 15 extends. The inlet of the first suction injection pump 14 is located near the base of the tank area 4a. The outlet of the first suction injection pump 14 extends into the vortex tank 8.

[0031] On the other hand, a second suction injection pump 16 is arranged in the right sub-region 4b, and the inlet of the second suction injection pump, into which the propellant nozzle 17 extends, is located near the base of the tank region 4b. A pipeline 23 extends from the outlet of the second suction injection pump 16 to the vortex tank 8, through which fuel is transported from the tank region 4b to the vortex tank 8 and from there to the two fuel pumps 10 and 12.

[0032] Downstream of the auxiliary fuel pump 12, a first pipeline connection point 18 is provided. From this first pipeline connection point, a first pipeline 20 leads to a first suction injection pump 14, and a second pipeline 22 leads to a second suction injection pump 16. Furthermore, a third pipeline 24 leads from the first pipeline connection point 18 to a first check valve 28, which is located downstream of the auxiliary fuel pump 12. A pipeline 30 leads from this first check valve to a second pipeline connection point 31, which is located downstream of the main fuel pump 10. A second check valve 26 is located between the main fuel pump 10 and the second pipeline connection point 31. Therefore, each of the two fuel pumps 10 and 12 has its own individual check valves 26 and 28. The fuel pressure downstream of the check valves 26 and 28 is maintained, and thus the fuel pressure in the supply lines to the internal combustion engine is also maintained. Furthermore, the first check valve 28 disconnects the hydraulic delivery circuit of the auxiliary fuel pump 12 from the delivery path of the main fuel pump 10, so that the auxiliary fuel pump 12 can be connected, for example, at near full load of the internal combustion engine, in a manner that supports the main fuel pump 10.

[0033] According to one embodiment, the main fuel pump 10 is sized to be less powerful than the auxiliary fuel pump 12 and is designed for a portion of the load range of the internal combustion engine. Here, across the full load range of the internal combustion engine, the more powerful auxiliary fuel pump 12 can be connected to the delivery path of the main fuel pump 10 via a check valve 28 to support the main fuel pump 10. In this case, the main fuel pump 10 can supply the internal combustion engine with a fuel volumetric flow rate, for example, up to 10 liters per hour. Here, a fuel pressure of approximately 5 to 6 bar can be established in the supply line to the internal combustion engine. On the other hand, a fuel pressure, for example, up to 1 bar, is sufficient to allow the auxiliary fuel pump 12 to operate the hydraulic delivery circuit while disconnected from the delivery path of the main fuel pump 10.

[0034] Pipeline 33 extends from the second pipeline connection point 31 to a connector formed on the flange 34 of the fuel delivery unit 6 and extends into the interior of the tank 4. A pressure relief valve 32 is also located downstream of the second pipeline connection point 31.

[0035] According to an alternative embodiment, the main fuel pump 10, which provides fuel supply and fuel pressure to the internal combustion engine, may also be equipped with a suction injection pump, which is supplied with a low fuel flow rate or a low propellant flow rate. From an energy point of view, such an embodiment remains better or more advantageous than systems known from the prior art.

[0036] A connector 38 for connection to the supply line leading to the internal combustion engine is formed on the side of flange 34 away from the inside of the housing. Terminals 36 arranged on flange 34 for electrical connection to the two fuel pumps 10, 12 are also shown.

[0037] A ventilation system is shown above the saddle-shaped box 4, which is attached to the box 4 via connection point 40. Piping leads from connection point 40 to activated carbon filter 42, which temporarily stores fuel vapor from the box 4. The fuel vapor is supplied to the internal combustion engine when the ventilation valve 44 is activated accordingly.

[0038] Although exemplary embodiments have been discussed in the above description, it should be noted that various modifications may be made. Furthermore, it should be understood that the exemplary embodiments are merely examples and are not intended to limit the scope, application, or structure in any way. Rather, the above description is intended to provide guidance to those skilled in the art for implementing at least one exemplary embodiment, wherein various modifications may be made, particularly regarding the functionality and arrangement of the described components, without departing from the scope of protection defined by the claims and these equivalent combinations of features.

Claims

1. A fuel delivery system for a vehicle, the fuel delivery system comprising: At least one main fuel pump (10) is used to supply fuel to the internal combustion engine by providing fuel pressure. At least one auxiliary fuel pump (12) supports the supply of fuel to the internal combustion engine by the at least one main fuel pump (10), the at least one auxiliary fuel pump being disconnected from the main fuel pump (10) and used to supply fuel injection to at least one suction injection pump (14, 16) as needed, and to set the pressure of the fuel injection before the nozzle of the suction injection pump (14, 16) independently of the main fuel pump (10). At least one main fuel pump is not assigned to a suction injection pump. The suction injection pumps provided in the fuel delivery system are assigned to multiple auxiliary fuel pumps. Compared to the auxiliary fuel pump (12), the main fuel pump (10) is determined to be less powerful and is designed for part of the load range of the internal combustion engine. At the full load range of the internal combustion engine, the more powerful auxiliary fuel pump (12) can be connected to the delivery path via a check valve (28) to support the purpose of the main fuel pump (10). The fuel delivery system further includes at least one suction injection pump (14, 16), which includes a first suction injection pump (14) and a second suction injection pump (16). The first suction injection pump (14) is located in or on the vortex tank (8) of the fuel delivery unit (6) in the first region (4a) of the fuel tank (4), while the second suction injection pump (16) is located in the second region (4b) of the fuel tank (4). The second suction injection pump (16) is used to deliver fuel from the second region (4b) of the fuel tank (4) to the first region (4a) of the fuel tank (4).

2. The system as claimed in claim 1, wherein, Downstream of the auxiliary fuel pump (12), a check valve (28) is provided, which disconnects the hydraulic delivery circuit of the auxiliary fuel pump (12) from the delivery path of the main fuel pump (10), and the auxiliary fuel pump (12) can be connected to support the main fuel pump (10) via the check valve.

3. The system as described in claim 2, wherein, Downstream of the auxiliary fuel pump (12) and before the check valve (28), there is a first pipeline connection point (18), from which at least one pipeline (20, 22) extends to the at least one suction injection pump (14, 16).

4. The system as described in claim 3, wherein, From the first pipeline connection point (18), the first pipeline (20) leads to the first suction jet pump (14), and the second pipeline (22) leads to the second suction jet pump (16).

5. The system as described in claim 3, wherein, A third pipeline (24, 30) extends from the first pipeline connection point (18) to a second pipeline connection point (31), which is located downstream of the main fuel pump (10), and a pipeline (33) is directed away from the second pipeline connection point for the purpose of supplying the internal combustion engine.

6. The system as claimed in claim 1, wherein, The at least one suction injection pump (14) is located in or on the vortex tank (8) of the fuel delivery unit (6).

7. The system as claimed in claim 1, wherein, The auxiliary fuel pump (12) is located in the area of ​​the main fuel pump (10).

8. The system of claim 1, wherein, The setting based on the required fuel injection pressure before the nozzle of the suction injection pump (14, 16) is achieved by means of the auxiliary fuel pump (12) for control or regulation.

9. The system of claim 8, wherein, The control or regulation is achieved by using at least one characteristic spectrum, a characteristic curve and / or a fixed value, taking into account the operating point of the suction jet pump.

10. The system as claimed in claim 8 or 9, wherein, This control or regulation is based on electric current.

11. A fuel tank for a vehicle, the fuel tank having a fuel delivery system (2) as described in any one of claims 1 to 10.

12. A vehicle having a fuel tank as claimed in claim 11.

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