WO2011020693A1

WO2011020693A1 - Fuel delivery device for a fuel injection device of an internal combustion engine

Info

Publication number: WO2011020693A1
Application number: PCT/EP2010/061211
Authority: WO
Inventors: Guenter Veit; Sylvain Besancon; Stefan Kieferle; Paulo Jorge Ferreira Goncalves; Cord Fitschen
Original assignee: Robert Bosch Gmbh
Priority date: 2009-08-17
Filing date: 2010-08-02
Publication date: 2011-02-24
Also published as: EP2467591A1; DE102010031628A1; EP2467591B1; CN102472209B; CN102472209A

Abstract

The invention relates to a fuel delivery device comprising an electrically driven delivery pump (10) and at least one high-pressure pump (16) having at least one pump element (22). Fuel is delivered by the delivery pump (10) to the intake side of the high-pressure pump (16) and fuel is delivered into a high-pressure region (18) by the high-pressure pump (16). A sensor device (44) provides a signal for the pressure present in the high-pressure region (18) to an electrical control device (46), by means of which the electrical drive (14) of the delivery pump (10) is variably actuated. A bypass connection (40) to a low-pressure region (12; 17) leads from the connection (xx) between the delivery pump (10) and the intake side of the at least one high-pressure pump (16). At least one throttle location (42) is provided in the bypass connection (40) and the electrical drive (14) of the delivery pump (10) is variably actuated by the electrical control device (46) for adjusting a prescribed pressure in the high-pressure region (18).

Description

description

title

Fuel delivery device for a fuel injection device of a

Internal combustion engine

State of the art

The invention relates to a fuel delivery device for a fuel injection device of an internal combustion engine according to the preamble of claim 1.

Such a fuel delivery device is known from EP 1 195 514 A2. This fuel delivery device has an electrically driven delivery pump through which fuel is conveyed to the suction side of a high-pressure pump. The high-pressure pump delivers fuel into a high-pressure region, from which at least indirectly at least one injector of the fuel injection device is supplied with fuel. An electrical control device is provided which receives a signal for the pressure prevailing in the high-pressure region via a sensor device. By the electric control device, the electric drive of the feed pump is variably controlled, so that the delivery rate of the feed pump is variable. Between the feed pump and the suction side of the high-pressure pump, a bypass connection leads to a low-pressure region, which here is a drive region of the high-pressure pump. Between the feed pump and the suction side of the high-pressure pump, a throttle point is arranged. In the connection between the feed pump and the suction side of the high pressure pump, a sensor device is arranged, through which the electrical control device, a signal for the pressure prevailing there is supplied. By the electric control device, the electric drive of the feed pump is controlled such that adjusts a predetermined pressure in the connection between the feed pump and the suction side of the high-pressure pump. Depending on the pressure prevailing on the suction side of the high-pressure pump

Pressure is variable by the amount of fuel delivered by the high-pressure pump. As a result of the throttle point arranged on the suction side of the high-pressure pump, however, a non-linear delivery characteristic of the high-pressure pump is produced. gig from the pressure prevailing on the suction side. This makes it difficult to control the amount of fuel delivered by the high-pressure pump. In the known fuel injection device also connected to the electrical control device sensor means is provided, through which the pressure in the high pressure region is detected. In the high pressure area, an electrically operated pressure control valve is arranged, which is controlled by the electric control device such that adjusts a predetermined pressure in the high pressure region. Overall, the fuel injection device is therefore complicated and the control of the pressure prevailing in the high-pressure area is expensive, since this is the pump and the pressure control valve two separate actuator available.

Disclosure of the Invention Advantages of the Invention

The fuel delivery device according to the invention with the features of claim 1 has the advantage that it is simple in construction and also allows a simple structure of the fuel injection device. The feed pump is thereby directly for setting a predetermined pressure in

High-pressure range controlled, so that no further actuator is required.

In the dependent claims advantageous refinements and developments of the fuel delivery device according to the invention are given. Since it is difficult in some circumstances to reduce the flow rate of the feed pump to zero, it is advantageous if the flow restrictor is dimensioned as specified in claim 2, since then the feed pump can be operated continuously. The embodiment according to claim 3 ensures that the flow rate of the high pressure pump can be reduced to zero even if the feed pump promotes fuel. The embodiment according to claim 5 allows a particularly simple control of the flow rate of the high-pressure pump.

Another advantage results from the parallel connection of two flow restriction units in the bypass connection, since the combination of a wider variation of the flow rate is possible depending on the pressure in the bypass connection. This advantage can be enhanced by an additional actuator, which the flow limiting device depending on the pressure or by the temperature in the inlet of the flow restrictor or in the inlet of the high-pressure pump off or switched on.

It is advantageous that the cross section of the throttle can be changed by an actuator depending on the pressure or the temperature in the inlet of the flow restrictor, since the throttle is not bound to a fixed flow characteristic, but that the flow characteristic of the throttle by varying the cross section depending on the operating situation the fuel delivery device can be adjusted.

Particularly advantageous is a large cross-section of the throttle at low temperatures or low pressure in the inlet of the throttle, and a reduced cross-section with increasing temperature or increasing pressure, since these measures at full load of the high pressure pump takes place a lower reflux through the bypass connection, so that the feed pump can be operated more energy efficient.

Another advantage is the use of a wax element, since the implementation of the temperature-dependent control of the cross section is realized with a simple component. The use of a vortex throttle is advantageous, since a pressure-dependent regulation of the flow rate can be implemented without an additional actuator.

DRAWING An embodiment of the invention is shown in the drawing and explained in more detail in the following description. Show it

1 shows a fuel injection device of an internal combustion engine in a schematic representation, 3 shows a characteristic curve of a bypass connection of the fuel injection device, FIG. 4 shows a characteristic curve of a high-pressure pump of the fuel injection device,

FIG. 5 is a schematic representation of a further exemplary embodiment of a fuel injection device of an internal combustion engine; FIG. 6 a) is a schematic representation of a vortex throttle and FIG

Characteristic of a vortex choke and

Figure 7 shows a further embodiment of a fuel injection device of an internal combustion engine in a schematic representation.

Description of the embodiment

FIG. 1 shows a fuel injection device of an internal combustion engine which has a fuel delivery device. The fuel delivery device has a feed pump 10, which draws fuel from a reservoir 12. The feed pump 10 has an electric drive 14 which can be operated with variable power and thus variable speed, so that the flow rate and the generated discharge pressure is variable. By the feed pump 10, fuel is conveyed to the suction side of at least one high pressure pump 16, which is also part of the fuel delivery device. By means of the at least one high-pressure pump 16, fuel is conveyed into a high-pressure region 18 of the fuel injection device, which comprises, for example, a high-pressure accumulator. One or more injectors 20 are supplied with fuel from the high-pressure region 18, wherein an injector 20 is assigned to each cylinder of the internal combustion engine.

The feed pump 10 may be formed, for example, as a flow pump, gear pump, internal gear pump, vane pump or roller-cell pump. The feed pump 10 can be arranged on the high-pressure pump 16, can be integrated in it or can be arranged remotely from the high-pressure pump 16. For example, in the reservoir 12 or in a hydraulic line between the reservoir 12 and the high-pressure pump 16. The high-pressure pump 16 has at least one pump element 22, which in turn has a tightly guided in a cylinder bore 24 pump piston 26 which is driven in a reciprocating motion. The high pressure pump 16 may have its own drive shaft 17 through which the lifting movement of the pump piston 26 is effected via a cam or eccentric. The drive shaft 17 of the high pressure pump 16 is mechanically driven, for example via a transmission or a belt drive from the internal combustion engine, so that the speed of the high-pressure pump 16 is proportional to the speed of the internal combustion engine. Alternatively, it can also be provided that the high-pressure pump 16 does not have its own drive shaft and the lifting movement of the pump piston 26 is effected by an eccentric or cam of a shaft of the internal combustion engine, for example the camshaft or crankshaft of the internal combustion engine. In this case, it is also possible to provide a plurality of high-pressure pumps 16 which each have a pump element 22 whose pump piston 26 is moved by the shaft of the internal combustion engine. By the pump piston 26 of each pump element 22, a pump working chamber 28 is limited in the cylinder bore 24, which is filled with fuel during the suction stroke of the pump piston 26 and 26 from the fuel pump in the high pressure region 18 is displaced during the delivery stroke of the pump piston. Each pump element 22 has an inlet valve 30 in the form of a spring-loaded check valve, which opens during the suction stroke of the pump piston 26, so that fuel delivered by the feed pump 10 reaches the pump work chamber 28. Each pump element 22 also has an outlet valve 32 in the form of a spring-loaded check valve, the

Delivery stroke of the pump piston 26 opens, so that fuel can be displaced into the high-pressure region 18.

The feed pump 10 can be arranged remotely from the at least one high-pressure pump 16, for example also in the storage container 12. The feed pump

10 is connected via a hydraulic line 36 to the suction side of the at least one high-pressure pump 16. In the conduit 36, a fuel filter 38 may be arranged to prevent dirt particles from entering the high-pressure pump 16 and the high-pressure region 18. From the line 36 branches downstream of the fuel filter 38 from a bypass connection 40 from which a low pressure area leads. In the bypass connection 40, a flow-limiting device in the form of a throttle point 42 is provided, by means of which the quantity of fuel flowing off via the bypass connection 40 of the quantity of fuel delivered by the delivery pump 10 is limited. In the bypass connection 40, in addition to the flow-limiting device 42, a still

Relief valve may be arranged, which opens the bypass connection 40 only when a predetermined pressure is exceeded. The low-pressure region into which the bypass connection 40 opens can, for example, be a drive region of the high-pressure pump 16 with its drive shaft 17. This is particularly advantageous when the high-pressure pump 16 has its own drive shaft 17 and lubrication and / or cooling of the drive region takes place by means of fuel. The throttle point 42 may be arranged in the bypass connection 40, for example, in the region of entry into the drive region of the high-pressure pump 16. Alternatively, the low-pressure region, into which the bypass connection 40 opens, may also be a return to the reservoir 12. This can be provided, in particular, if the at least one high-pressure pump 16 does not have its own drive shaft and lubrication of the drive region of the high-pressure pump 16 is effected by lubricating oil of the internal combustion engine. In the high-pressure region 18, a sensor device 44 is provided, by which the pressure prevailing in the high-pressure region 18 is detected. The sensor device 44 is connected to an electrical control device 46, which is thus supplied with a signal for the pressure prevailing in the high-pressure region 18. By the electric control device 46 of the electric drive 14 of the feed pump 10 is driven with variable power and thus variable speed, such that adjusts a predetermined pressure in the high pressure region 18. The pressure required in the high-pressure region 18 can vary depending on operating parameters of the internal combustion engine. The electric control device 46 also controls the fuel injection through the injectors 20, for example with regard to the injection time and the injection quantity.

FIG. 2 shows a characteristic curve for the delivery characteristic of the feed pump 10. In FIG. 2, the delivery flow, that is to say delivery rate per unit time, of the delivery pump 10 is applied above the delivery pressure of the delivery pump 10. The characteristic has an at least approximately linear course, that is, the flow rate and thus the delivery rate of the feed pump 10 increases linearly with the delivery pressure. This means that with increasing control performance and thus rotational speed of the electric drive 14 of the feed pump 10, the conveying flow or fuel quantity conveyed by it and the delivery pressure generated by this on the suction side of the high-pressure pump 16 increases at least approximately linearly. In order to ensure a stable operation of the feed pump 10, it is usually necessary that this is operated with a certain minimum drive power and thus minimum speed, so that the flow rate and flow rate and the discharge pressure can not be reduced to zero. Preferably, the feed pump 10 is therefore driven with a certain minimum power and operated at a minimum speed, with a minimum flow rate or a minimum flow rate QO and a minimum delivery pressure pθ set. The minimum delivery pressure pθ may be, for example, about 2 bar absolute or greater. Minimum delivery pressure pθ and minimum delivery rate or minimum delivery rate are preferably chosen as low as possible in order to keep the load on the delivery pump 10 and the energy requirement low.

FIG. 3 shows a characteristic curve for the flow characteristic of the bypass connection 40 with the throttle restriction 42. Here, in Figure 3, the flow rate, that is flow rate per unit time, through the bypass connection 40 with the throttle point 42 above the delivery pressure of the feed pump 10, that is, the pressure prevailing on the suction side of the high-pressure pump 16 pressure applied. The characteristic curve has a degressive profile, that is to say that the increase in the flow rate or the flow rate through the bypass connection 40 decreases as the delivery pressure of the delivery pump 10 increases. This means that with increasing from the feed pump on the suction side of the high-pressure pump 16 generated delivery pressure of the flow or the flow rate through the bypass connection increases less. The opening pressure of the intake valve or valves 30 of the high-pressure pump 16 is so high that they are at least substantially closed at the minimum delivery pressure pθ on the suction side of the high-pressure pump 16. Thus, the high pressure pump 16 promotes at least substantially no fuel in the high pressure region 18 at the minimum delivery pressure pθ generated by the feed pump 10 on the suction side thereof. The entire minimum delivery flow QO of the feed pump 10 thus flows through the bypass connection 40 with the throttle body 42 in the low pressure region. The throttle point 42 in the bypass connection 40 is dimensioned such that the entire minimum delivery flow QO of the feed pump 10 can flow through it without the pressure on the suction side of at least one high-pressure pump 16 rising above the minimum feed pressure pθ and the intake valve or valves 30 of the high-pressure pump 16 would open. Another design criterion of the throttle point 42 may be to ensure a sufficient amount of lubricant and / or cooling for the drive range of the at least one high-pressure pump 16. Only when the delivery pressure on the suction side of the at least one high-pressure pump 16 rises above the minimum delivery pressure pθ and the opening pressure of the intake valve or valves 30 do they open and fuel is delivered through the high-pressure pump 16 into the high-pressure region 18. The opening pressure of the intake valve or valves 30 For example, the at least one high pressure pump 16 may be about 2 bar absolute or greater.

FIG. 4 shows a characteristic curve for the delivery characteristic of the at least one high-pressure pump 16. In this case, in Figure 4, the flow rate, that is flow rate per unit time, the high pressure pump 16 above the delivery pressure of the feed pump 10, that is, the pressure prevailing on the suction side of the high-pressure pump 16 pressure applied. As already explained above, fuel is delivered by the high-pressure pump 16 only when the pressure on the suction side thereof is higher than the minimum delivery pressure pθ, which may be, for example, about 2 bar absolute. The characteristic curve has a continuous monotonous course starting from the minimum delivery pressure pθ, preferably an at least approximately linear one

Course on, that is, that the flow rate and thus the flow rate of the high-pressure pump 16 at least approximately linearly with the delivery pressure generated by the feed pump 10, ie the pressure prevailing on the suction side of the high-pressure pump 16 pressure increases. The one or more intake valves 30 of the at least one high-pressure pump has a design which ensures, via increasing pressure on the suction side of the high-pressure pump 16 above the opening pressure, a steadily increasing filling of the pump working space 28 of the pump element or elements 22 of the high-pressure pump 16. The increase of the flow cross-section released by the inlet valves 30 as a function of the pressure on the suction side of the high-pressure pump 16 is to be selected such that the maximum Ie flow rate requirement of the high-pressure pump 16 is reached at the usual maximum delivery pressures of conventional feed pumps, which may be, for example, to about 5 bar absolute. By varying the electrical control of the drive 14 of the feed pump 10 by means of the electrical control device 46, a precisely adjustable delivery rate of the high-pressure pump 16 into the high-pressure region 18 over the entire required flow rate range is made possible. The resulting flow rate variation of the high-pressure pump 16 is continuously and monotonically and thus suitable as a manipulated variable for regulating the pressure prevailing in the high-pressure region 18 via the electrical control variation of the electric drive 14 of the feed pump 10 by means of the electrical control device 46.

The line 36, via which the feed pump 10 is connected to the suction side of the at least one high-pressure pump 16, preferably has a high hydraulic rigidity. This ensures that the regulation of the pressure in the high-pressure region 18 by means of variable activation of the drive 14 of the feed pump 10 is not influenced by elasticities of the line 36. Under certain circumstances, it may be advantageous to carry out the section 36a of the line 36 between the feed pump 10 and the fuel filter 38 with great hydraulic rigidity and the section 36b of the line 36 between the fuel filter

38 and the suction side of the at least one high-pressure pump 16 with lower hydraulic rigidity. As a result, the propagation of pressure fluctuations generated by the at least one high-pressure pump 16 can be damped.

The design and tuning of the intake valves 30 of the high-pressure pump 16, the bypass connection 40 with the throttle point 42 and the feed pump 10 takes place according to the following criteria. The opening pressure of the intake valves 30 requires a minimum pressure level on the suction side of the high-pressure pump 16 to ensure the following. At a defined minimum pressure pθ on the suction side (relative overpressure to the environment), which also corresponds to the minimum delivery pressure of the feed pump 10, the flow rate of the high-pressure pump 16 must be reduced to a required minimum, preferably also completely off, for a so-called zero promotion. At this defined minimum pressure pθ (remaining relative overpressure), one results from the Laying the bypass connection 40 with the throttle body 42 dependent Mindestför- amount of the feed pump 10, which can be used as needed as described above as lubrication and / or cooling amount for the drive range of the high pressure pump 16.

The minimum pressure pθ on the suction side of the high-pressure pump 16 is to be selected so high over the height of the opening pressure of the inlet valves 30 of the high-pressure pump 16 that the fuel conveyor is on the one hand sufficiently robust, for example against tolerances of line pressure drops and ambient pressure fluctuations, and on the other hand no unnecessarily high pumping capacity requirements the feed pump 10 result. As an example, the opening pressure of the intake valves may be selected to be in the range of about 2 bar absolute, so that a delivery pressure range of the delivery pump 10 results relatively greater than about 1 bar. The inlet valves 30 of the high pressure pump 16 are designed so that they ensure a steadily increasing filling of the high pressure pump 16 with increasing pressure on the suction side of the high pressure pump 16 above the opening pressure. The increase in the released flow cross section of the inlet valves 30 above the pressure difference, between the pressure on the suction side of the high-pressure pump 16 and the pressure in the pump working space 28, is designed so that the maximum flow rate requirement of

High-pressure pump 16 at conventional delivery pressures of conventional low-cost feed pumps 10 with electric drive 14 is achieved. The maximum delivery pressure can be about 4 bar relative or 5 bar absolute. By the bypass connection 40 with the throttle body 42, a large flow rate variation of the high pressure pump 16 is achieved via a limited variation of the pressure generated by the feed pump 10 on the suction side of the high pressure pump 16. The variation of the amount of fuel flowing through the bypass connection 40 is determined by the throttle point 42 and is limited. The design of the throttle body 42 in the bypass connection 40 is such that the amount of fuel flowing through the bypass connection 40 on the one hand as small as possible, on the other hand, however, is large enough to ensure adequate lubrication and / or cooling of the drive range of the high-pressure pump 16 and the possibly required Minimum delivery rate of the delivery pump 10 is not fallen short of. The feed pump 10 and its electric drive 14 are designed such that a stable operation over the entire working range, that is from minimum flow rate or flow and delivery pressure to the maximum Fördermen- ge or flow rate and delivery pressure is guaranteed. The minimum delivery rate at minimum delivery pressure is determined by the opening pressure of the intake valves 30 of the high pressure pump 16 and the resulting amount of fuel flowing out of the bypass connection 40. The maximum delivery rate or delivery rate at maximum delivery pressure is determined by the required filling pressure of the high-pressure pump

16 for the rated power of the internal combustion engine plus possible line and filter pressure drops at maximum delivery quantity requirement in the high-pressure region 18 plus the amount of fuel flowing out through the bypass connection 40.

In Figure 5, an alternative embodiment of the invention is shown in which the cross section of the throttle 42 can be varied by a mechanical or electrical actuator 44. This actuator 44 may control the cross section of the throttle 42 depending on the pressure or the temperature in the bypass connection 40 or in the inlet of the throttle 42. This allows for a variation of

Flow rate of the fuel through the bypass connection 40 depending on the pressure or the temperature of the fuel. If an electrically controlled actuator 44 is provided, then this can be controlled by software in the electrical control device 46.

Since at low fuel temperatures often a large minimum flow rate, flow rate per unit time, the feed pump 10 must be adjusted, it is advantageous if the maximum cross section of the throttle 42 is open at low fuel temperatures. In order to prevent this high fuel return from occurring even at high fuel delivery rates or at full delivery of the high pressure pump 16, the cross section of the throttle 42 can be continuously reduced with increasing temperatures.

The actuator 44 may also have the cross-section of the throttle depending on the pressure in the inlet to the high-pressure pump 16 or depending on the pressure in the Bypassverbin- 40 or in the inlet to the throttle 42 vary. Again, at a low pressure, the maximum cross section of the throttle 42 should be open and be reduced with increasing pressures. Due to the reduced cross-section of the throttle 42 is at full promotion of

High-pressure pump 16 a high return amount of fuel through the bypass passage 40 avoided, so that the fuel delivery device can be designed more energy efficient and cheaper. But there can be other types of control of the cross section of the throttle

42 may be provided, e.g. a cross-sectional reduction in stages or an increase in the cross-section with increasing pressure or with increasing temperature. As a possible actuator 44 for temperature-dependent control of the throttle offers a wax element or bimetallic element.

FIG. 6a shows a vortex throttle by the use of which a reduction of the flow rate through the bypass connection 40 can be realized with increasing pressure. With a vortex throttle, the flow increases less with increasing pressure than with a standard throttle. Figure 6b shows a diagram in which the flow above the applied pressure for a standard throttle (A) and a vortex throttle (B) are shown. Furthermore, instead of a flow-limiting device 42, the possibility of arranging at least two flow-limiting devices 42 in the bypass connection 40 as shown in FIG. 6 is parallel. As described in the previous sections, at least one throttle 42 can be varied by an additional mechanical or electrical actuator 44 with respect to its cross section depending on the pressure or the temperature. There are all previously mentioned variants for varying the throttle cross-section possible.

Another mechanical or electrical actuator 52, which is located in front of or behind at least one throttle 42, can be used to the Flow through the hydraulic line in which the throttle 42 is to interrupt. If it is an electrical actuator 52, it is controlled by the electrical control device 46. The actuator 52 may open or close the hydraulic line depending on a measured in the inlet of the bypass connection 40 temperature or measured in the inlet of the bypass connection 40 pressure. It is advantageous to open the hydraulic line at low pressures or low temperatures and close otherwise, as this high flow at low temperatures and low pressures is possible. At high temperatures and high pressures, which correspond to a high flow rate of the high pressure pump 16, however, only a small amount of fuel flows through the bypass connection 40th

Claims

claims

1. A fuel delivery device for a fuel injection device of an internal combustion engine with an electrically driven delivery pump (10) and with at least one high pressure pump (16) with at least one pump element (22), wherein conveyed by the feed pump (10) fuel to the suction side of the high pressure pump (16) is conveyed by the high pressure pump (16) fuel in a high pressure area (18), with an electrical control device (46) via a sensor device (44) a signal for the pressure prevailing in the high pressure region (18) pressure is supplied and by the electric drive (14) of the feed pump (10) is driven variably, wherein from the connection (36) between the feed pump (10) and the suction side of the at least one high pressure pump (16) a bypass connection (40) to a low pressure region (12; 17), characterized in that in the bypass connection (40) at least one flow-limiting device (42) of at least is seen and that by the electric control device (46) of the electric drive (14) of the feed pump (10) for setting a predetermined pressure in the high pressure region (18) is variably controlled.

2. Fuel delivery device according to claim 1, characterized in that the at least one flow-limiting device (42) in the bypass connection (40) is dimensioned such that the for proper operation of the feed pump (10) required minimum delivery of the feed pump (10) by the Bypass connection (40) can flow without the at least one high-pressure pump (16) promotes fuel.

3. Fuel delivery device according to claim 2, characterized in that the at least one high-pressure pump (16) has a spring-loaded inlet valve (30) on the suction side for each pump element (22), and that the inlet Lassventil (30) opens only at a higher pressure on the suction side of the at least one high-pressure pump (16) than at the pressure, which sets in promoting the minimum delivery of the feed pump (30) on the suction side of the at least one high-pressure pump (16).

4. Fuel delivery device according to claim 3, characterized in that the inlet valve (30) opens at an absolute pressure on the suction side of the at least high pressure pump (16) of at least about 2 bar or higher.

5. Fuel delivery device according to claim 3 or 4, characterized in that the feed pump (10) and the inlet valve (30) are matched to one another such that at above the opening pressure of the inlet valve (30) lying pressure on the suction side of the at least one high-pressure pump ( 16) in the case of a monotonically constant change in the pressure on the suction side of the at least one high-pressure pump (16), a monotonically continuous change in the

Flow rate of at least one high-pressure pump (16) results.

6. Fuel delivery device according to one of the preceding claims, characterized in that the feed pump (10) away from the at least one NEN high-pressure pump (16) is arranged and with the suction side of the at least one high pressure pump (16) via a line (36) with high hydraulic rigidity is connected.

7. Fuel feed device according to one of claims 1 to 5, character- ized in that the feed pump (10) remote from the at least one

High pressure pump (16) is arranged, that in the connection between the feed pump (10) and the suction side of the at least one high-pressure pump (16), a fuel filter (38) is arranged, that the connection between the feed pump (10) and the fuel filter (38) comprises a high hydraulic rigidity duct (36a) and that the connection between the

Fuel filter (38) and the suction side of the at least one high pressure pump (16) comprises a line (36b) with low hydraulic stiffness.

8. Fuel delivery device according to one of the preceding claims, characterized in that the bypass connection (40) leads to a drive region (17) of the at least one high-pressure pump (16).

9. Fuel delivery device according to one of claims 1 to 7, characterized in that the bypass connection (40) leads to a fuel tank (12).

10. Fuel delivery device according to one of the preceding claims, characterized in that the bypass connection (40) has at least two flow-limiting devices (42) which are arranged parallel to each other.

11. Fuel delivery device according to claim 10, characterized in that an additional actuator (52) the flow limiting device (42) depending on the pressure or the temperature in the inlet of the flow limiting device (42) off or switched on.

12. Fuel delivery device according to one of the preceding claims, characterized in that the flow-limiting device (42) is designed as a throttle point (42).

13. A fuel delivery device according to claim 12, characterized in that the cross section of the throttle (42) by a mechanical or electrical actuator (44) depending on the pressure or the temperature in the inlet of

Throttle (42) or the high-pressure pump (16) is changed.

14, fuel delivery device according to claim 13, characterized in that at high temperature, a smaller cross section of the throttle (42) is opened than at a lower temperature.

15. Fuel delivery device according to claim 14, characterized in that the cross section of the throttle (42) is continuously reduced with increasing temperature.

16, fuel delivery device according to claim 13, characterized in that at high pressure, a smaller cross section of the throttle (42) is open than at low pressure.

17. Fuel delivery device according to claim 16, characterized in that the cross section of the throttle (42) is continuously reduced with increasing temperature.

18. Fuel delivery device according to claim 13 to 15, characterized marked, that a wax element controls the cross section of the throttle (42).

19. Fuel delivery device according to claim 1 to 10, characterized in that at least one flow-limiting device (42) is a vortex throttle (50).