CN108138726B

CN108138726B - High-pressure fuel pump and method for reducing non-uniformity in driving force of high-pressure fuel pump

Info

Publication number: CN108138726B
Application number: CN201680058193.3A
Authority: CN
Inventors: T.施密德鲍尔
Original assignee: Continental Automotive GmbH
Current assignee: Vitesco Technologies GmbH
Priority date: 2015-10-05
Filing date: 2016-09-27
Publication date: 2020-12-11
Anticipated expiration: 2036-09-27
Also published as: KR20180059934A; WO2017060131A1; DE102015219153B4; CN108138726A; DE102015219153A1

Abstract

A high-pressure fuel pump and a method for reducing non-uniformity of driving force of a high-pressure fuel pump with a pump unit are described. The high-pressure fuel pump includes: a pump unit; a driving unit that drives the pump unit by a driving force; a valve with a settable flow, said valve being hydraulically coupled to the pump unit; and a control unit for determining the driving force and for controlling the flow of the valve in dependence on the driving force.

Description

High-pressure fuel pump and method for reducing non-uniformity in driving force of high-pressure fuel pump

Technical Field

The invention relates to a high-pressure fuel pump and a method for reducing non-uniformity in driving force of the high-pressure fuel pump.

Background

Fuel pumps are used in many modern vehicles with excellent performance. More recently, the classical fuel pump has been replaced by an improved high pressure fuel pump. The high pressure fuel pump delivers fuel to the motor at an increased pressure (up to 3000 bar in the case of a diesel motor). The efficiency of modern motors can thereby be improved. However, fluctuations in the driving force of the high-pressure fuel pump, either strong or weak, and thus non-uniformity occur due to the high pressure. The non-uniformity causes vibrations that propagate to surrounding structural components and impose heavy mechanical loads on the surrounding structural components. In the worst case, resonance can also occur in the high-pressure fuel pump or in one of the surrounding structural components and damage them. The unevenness in the driving force is based on different resistance ratios in the interior of the high-pressure fuel pump. The driving force required by the pump may thus fluctuate greatly (the transfer flow pulsation) during operation of the pump and subsequently react to the driving members of the high-pressure fuel pump. However, the high-pressure fuel pump is generally driven with a driving force that is substantially kept constant. Therefore, during operation of the high-pressure fuel pump, a greater or lesser difference occurs between the supplied driving force and the force actually required by the fuel pump. Subsequently, the above-described unevenness is generated in the driving force. Up to now, the surrounding and adjacent structural components of the high-pressure fuel pump have accordingly been correspondingly strong and therefore of heavy design.

Disclosure of Invention

The invention is based on the object of reducing inhomogeneities in the drive force of a high-pressure fuel pump.

This object is achieved by a high-pressure fuel pump comprising: a pump unit; a driving unit that drives the pump unit by a driving force; a valve with a settable flow, said valve being hydraulically coupled to the pump unit; and a control unit for determining the driving force and for controlling the flow of the valve in dependence on the driving force. The advantage is that the compensation of inhomogeneities in the driving force can be carried out by means of a possibly already existing structure.

In one embodiment of the high-pressure fuel pump, the driving force may be derived from the currently required driving force of the pump unit. Using the required driving force of the high-pressure fuel pump enables to detect without error the currently actually received driving force of the high-pressure fuel pump.

In an embodiment of the high-pressure fuel pump, the control unit may derive said driving force from a combined characteristic curve (Kennfeld) of the pump unit. In this way, the sensor unit can be dispensed with.

For example, the high-pressure fuel pump may be equipped with a first sensor unit for acquiring the driving force. This has the following advantages: the inhomogeneities can be detected near their production location.

According to another embodiment of the high-pressure fuel pump, the pump unit may be driven by a shaft with at least one cam, and the first sensor unit may directly or indirectly take the driving force on the shaft. The advantage is that the high-pressure fuel pump does not have to be driven by a complex linear drive.

In one embodiment of the high-pressure fuel pump, the acquisition of the driving force may be performed by the second sensor unit. The driving force may alternatively be acquired by the second sensor unit, or the acquisition of the driving force may be performed redundantly by the first and second sensor units.

In one embodiment of the high-pressure fuel pump, the second sensor unit may be arranged in a working space of the pump unit or hydraulically connected to the working space. This arrangement has the following advantages: the sensor unit is not mounted in the vicinity of a movable structural component, such as a shaft.

For example, the second sensor unit may be a pressure sensor. The technical advantage is that the pressure sensor can be produced and used inexpensively.

Furthermore, the object is achieved by a method for reducing inhomogeneities in the drive force of a high-pressure fuel pump, wherein the high-pressure fuel pump has a valve hydraulically coupled to a pump unit. The method comprises the following steps: information about the driving force of the pump unit is acquired, the acquired information about the driving force is processed, and the at least one valve is operated in accordance with the acquired information about the driving force. The advantage is that a dynamic adjustment of the currently present non-uniformity in the driving force can be achieved.

In one embodiment, the information about the driving force may be at least partially obtained from a combined characteristic curve or by measurement. Whereby the information can be detected with high accuracy.

In another embodiment, the provided information about the driving force may be compared to a predefined threshold. The following advantages are thereby obtained: the unevenness of the driving force can be classified and distributed.

In another example, the actuation of the at least one valve may be performed only when a predefined threshold value is exceeded or fallen below. The actuation of the valve is only carried out when technically reasonable.

For example, the driving force may be a currently required driving force of the pump unit. The currently required driving force is particularly suitable for detecting the unevenness of the driving force without error.

Drawings

An example of the high-pressure fuel pump and an example of a method for reducing the unevenness of the driving force of the pump unit are further explained below with the aid of the drawings. These drawings are provided to illustrate basic aspects. The figures are not necessarily to scale, wherein like reference numerals designate identical or similar components having correspondingly identical or similar design or operating principles.

FIG. 1 illustrates an exemplary high pressure fuel pump in circuit diagram;

fig. 2 shows the high-pressure fuel pump according to fig. 1 in a circuit diagram in conjunction with a drive unit; FIG. 3 illustrates an exemplary high pressure fuel pump in circuit diagram;

FIG. 4 shows another exemplary high-pressure fuel pump in circuit diagram with a pump unit and a sensor unit in a working space of the pump unit;

FIG. 5 shows in a graph a plot of the driving force of the pump unit as a function of time and a predefined threshold value;

fig. 6 illustrates an exemplary method for reducing non-uniformity of driving force in a flowchart.

Detailed Description

Fig. 1 shows a high-pressure fuel pump having a pump unit 10, which is designed to control the flow of valves 11 and/or 12 by means of a control unit 30. "flow rate" is understood here to mean the flow rate per time unit, for the duration of the flow rate or for the time at which at least one

valve

11 or 12 is at least partially opened or closed. In the driving of the pump unit 10, during operation, a driving force F may occur_AOr strong or weak fluctuations. Driving force F_AThe cause of the fluctuations may be, for example, a change in the internal resistance of the pump unit 10 during operation. "Driving force F_A"is understood to mean, for example, the currently required drive force of the pump unit 10 (the force that the pump unit 10 can currently withstand (aufnehmen)). The currently required driving force may be such a driving force F_AThis driving force is required so that the pump unit 10 can deliver a predefined delivery flow (siderstrom).

When the pump unit 10 is driven, losses of different magnitudes may occur depending on the type of force transmission. When driven by a belt drive, for example, a portion of the drive energy can be converted into heat by the belt. If the driving force F is detected at the driving unit 51_AMay lead to detection of only the driving force F_ABecause a part of the unevenness may have been compensated for by the (endless) belt tensioning (Riemendehnung). The actuation of the valves 11 and/or 12 by the controller 30 therefore depends considerably on the positions at which the drive force F is obtained in the drive of the pump unit 10_A. In order to effectively control the valves 11 and/or 12, it is therefore conceivable to use the currently required (or accepted) drive force of the pump unit 10 as the basic drive force F_A. For this purpose, the currently required driving force can be taken near the pump unit 10, in particular at the (drive) shaft 13 of the pump unit 51. This reliably reduces the disturbing influence of the elasticity in the drive of the pump unit 10. In the following description, the driving force currently required (or received) is referred to as a driving force F_A。

The high-pressure fuel pump shown can reduce the drive force F by a predefined actuation of at least one

valve

11 or 12_AIs hydraulically connected to the pump unit 10. By "hydraulically connected" it is understood that the

valves

11 and 12 are arranged in a circuit of the pump unit 10 and can be traversed by the same transport medium which flows through the pump unit 10. The controller 30 can process information of the pump unit 10 representing the driving force and operate at least the valves 11 and/or 12 on the basis of this information. As a pump unit 10 may use different kinds of pumps, such as for example an extrusion pump (Verdr ä rpumpen) or a flow pump (strumpspump). As an alternative thereto, the described control of the high-pressure fuel pump can also be used in blowers and compressors. The displacement pump can be, for example, a piston pump, in particular a reciprocating piston pump, a diaphragm pump or a bellows pump (Balgpumpen). The high-pressure fuel pump may deliver diesel or gasoline, for example, at pressures between 1500 bar and 3000 bar (in the case of diesel) and between 150 bar and 500 bar (in the case of gasoline). These pressure ranges can be referred to as high pressures in conjunction with the fuel pump.

For example, the driving force F of the pump unit 10_ACan have a driving force F at uniform (regelm ä beta sig) intervals as shown in FIG. 3_AOf the maximum value 61. Accordingly, the controller 30 can operate at least the valve 11 and/or the valve 12 and adjust the flow thereof in a suitable manner. For example, the throughflow of the valve 11 and/or the valve 12 can be increased in order to reduce the resistance in the pump unit 10, which resistance can be produced by the valve 11 or the valve 12. Subsequently, the driving force F of the pump unit 10 can be reduced_AOf the series 61. Alternatively or additionally, the opening time of the valve 11 and/or the valve 12 can also be adjusted. The opening time may be shortened, lengthened, and/or the time at which the valve 11 and/or the valve 12 is closed and/or opened may be changed, for example. Whereby the driving force F can be reduced as well_AFluctuation in the mean time. The corresponding situation can also apply to the driving force F_AOf the minimum value of 62. In this case, the valve 11 and/or the valve 12 can also be opened or closed in a suitable manner by the controller 30. The throughflow can be controlled at the valve 11 and/or the valve 12, for example by means of a variable offset (Hub). In addition, the controller 30 may be configured to operate other valves, either alone or in combination with the valves 11 and/or 12, in an appropriate manner. Any type of valve can be used as a valve, such as, for example, a check valve, a shut-off valve, a pressure relief valve, a throttle valve or a bypass valve. The valve can also be a controllable valve, like for example a solenoid valve. Different types of valves may also be combined with each other.

The controller 30 can pressRepresenting driving force F according to a predefined algorithmic process_AThe information of (1). In the following description, the driving force F is indicated_AIs referred to as information only or as information on the driving force F_AThe information of (1). Here, the manner and method for obtaining the driving force F_AThe information of (a) is irrelevant. Driving force F_ACan be derived from the combined characteristic curves of the pump units 10. For example, the controller 30 can be configured in the following manner: the controller is able to derive information about the driving force F from a previously stored combination characteristic curve of the pump unit 10_AThe information of (1). Instead of this, the driving force F_AOr may be obtained indirectly or directly by measurement. For this purpose, for example, a first sensor unit 20 can be used, which during operation receives the drive force F_AAnd passes it to the controller 30. The first sensor unit 20 can acquire the driving force F in various ways_A. Capacitive, inductive or also optical measuring methods, for example, can be used here. In addition, any combination of the above-mentioned methods may be used. For example, it is furthermore possible: the controller 30 operates valves hydraulically connected to the pump unit 10 and in this way drives the force F_ARemain substantially constant. The actuation of the valves 11 and/or 12 can be effected, for example, hydraulically, electrically or pneumatically. In addition, mechanical manipulation is also possible. Combinations of different control methods are also conceivable.

Another example of a high pressure fuel pump is shown in fig. 2. The drive unit 51 serves for driving the pump unit 10 and can be designed in different ways. The drive of the pump unit 10 can take place linearly (for example by means of a linear drive) or by a rotary motion (for example by means of a camshaft) in conjunction with a rotary motor (rotationmotor). In the example shown, the driving force F is related to the pump unit 10_ACan be detected by the first sensor unit 20, which is arranged here on the drive unit 51. The drive unit 51 may provide a driving force F for the pump unit 10_A. The drive unit 51 may be directly or indirectly (via a transmission) connected to the pump unit10 are connected.

Fig. 3 shows an example of a high-pressure fuel pump having a drive unit 51 which acts by a rotary motion. In this example, the pump unit 10 is a piston pump. By means of the piston 15, which is moved linearly between two dead points, the transport medium can be transported by the pump unit 10 and subsequently to a destination for the transport medium. The pump cycle may, for example, consist of a first and a second pump cycle (Pumpentakt). In a first pumping cycle, the feed medium can be sucked into the working space 16 of the pump unit 10 via the channel 52, in which the valve 11 can be located. Subsequently, in a second, subsequent pump cycle, the transport medium can be transported via the channel 53, in which the valve 12 can be located. This process can be carried out cyclically and thus ensures a continuous transport flow. As transport medium, all types of fluids can be used, such as gases and liquids, for example fuel or oil for internal combustion engines. In the example shown, the piston of the piston pump is pressed against the cam 14 by a spring-loaded tappet 17. The tappet 17 is connected to the piston 15 on a first side and is mounted on the cam 14 in a rolling manner on a second side opposite the first side. The cam 14 is in turn fixedly connected to the shaft 13. The shaft 13 is supported in the housing and can project from the housing at least on one side. At the end of the shaft 13 projecting from the housing of the pump unit 10, a belt pulley or a gear wheel, for example, can be mounted.

In the high-pressure fuel pump according to fig. 3, the first sensor unit 20 operates without contact. The first sensor unit 20 may be, for example, a capacitive, inductive or optical sensor unit. In this example, the first sensor unit 20 may be composed of a transmitter unit 21 and a receiver unit 22. Both the transmitter unit 21 and the receiver unit 22 can be active and/or passive structural elements. In this case, the driving force F of the pump unit 10 acquired by the first sensor unit 20_ACan also be derived from the torque that can be exerted on the shaft 13. The torque is realized by the following way: the piston of the pump unit 10 can be moved not linearly but by a rotary movement of the shaft 13. In-line driverIn the case of a linear drive that directly drives the pump unit 10 (as briefly described additionally above), a force can be taken instead of a torque. The "driving force F" is according to the type and arrangement of the driving unit 51_A"in addition to force or torque, may also be understood as being suitable for deriving the driving force F_AEach other parameter of (1).

The driving force F is to be explained below by means of the inductively operating first sensor unit 20_AAnd (4) obtaining. The transmitter unit 21 can in turn be composed of a plurality of individual transmitters, which can be arranged radially on the shaft 13 and which, during operation, surround the shaft 13 (umlaufen). The receiver unit 22 can be arranged in the housing with a predefined spacing from the transmitter unit 21. As soon as the transmitter, for example a magnet, of the transmitter unit 21 passes by the receiver unit 22 during operation, a voltage pulse is induced into the receiver unit 22. The voltage pulses may be interpreted and further processed by the controller 30. Depending on the number of transmitters in the transmitter unit 21 and the number of receivers in the receiver unit 22, the required driving force F can be set_AResolution accuracy of (2). It is applicable here that increasing the number of transmitters in the transmitter unit 21 and the number of receivers in the receiver unit 22 may lead to a higher resolution accuracy. It is also possible to arrange the receiver unit 22 on the shaft 13 and conversely the transmitter unit 21 in the housing. It is furthermore possible that: the high-pressure fuel pump comprises a further sensor unit, which is likewise designed to detect at least partially the driving force F_AThe information of (1).

In another example of the high-pressure fuel pump shown in fig. 4, the high-pressure fuel pump has a second sensor unit 23, which can be hydraulically connected to the working space of the pump unit 10. The second sensor unit 23 may in this example be a pressure sensor and is mounted in addition to or instead of the first sensor unit 20. The second sensor unit 23 can be a sensor unit that operates according to different methods, as already described in connection with the first sensor unit 20, and can compriseIncluding one or more receivers and transmitters. The pressure sensor transmits a signal to the control 30 about the currently prevailing pressure ratio in the working space 16 of the pump unit 10. The pressure may be measured over a predefined time interval. In particular, the measurement interval can be adapted to the rotational speed and the drive force F of the pump unit 10_A. The pressure can be measured, for example, 30 times, in particular 20 times, in one pump cycle (intake cycle and discharge cycle). Furthermore, in fig. 4 is also shown: the controller 30 may be integrated into a motor controller (ECU = Electronic Control Unit) for a motor vehicle, for example.

In the controller 30, the acquired driving force F may be set_ACompared to predefined thresholds 41 and/or 42. The controller 30 can be configured in the following manner: the actuation of the valve 11 and/or the valve 12 takes place only when a predefined threshold value 41 and/or a predefined threshold value 42 is/are undershot and/or exceeded. The control pulses can be reduced in this way to the required magnitude, wherein the

thresholds

41 and 42 can be matched to the load capacities of the surrounding components in the drive unit 51. In the case of correctly configured

thresholds

41 and 42, no overloading of the structural components of drive unit 51 is expected. Fig. 5 shows the driving force F_AFunction 43 with

thresholds

41 and 42 with respect to time. From fig. 5, it can be seen that: in this example, the driving force F_AThe function 43 of (a) slightly exceeds the threshold 41 at a particular time. The corresponding applies for being below the threshold 42.

Fig. 6 shows the drive force F for reducing the pump unit 10_AA flow chart of a method of non-uniformity. An exemplary flow chart includes: acquiring (101) a driving force F with respect to the pump unit 10_AThe information of (1). This is to be understood as all conceivable ways of causing the controller 30 to obtain information about the driving force F on the pump unit 10_AThe information of (1). For example, the driving force F can be inferred from a characteristic curve of the pump unit 10_AThe information of (1). Instead of this, the information can be obtained from each suitable function and from each suitable measuring device. The driving force F for the pump unit 10 may then be further processed (102)_AThe information of (1). "advance toOne-step processing "is understood in this case to mean: driving force F_AAnd the output of control signals for valves 11 and/or 12. This interpretation can be made, for example, by: the obtained driving force F with respect to the pump unit 10_AIs contextually studied along with other inputs, such as user input or other suitable parameters. A suitable parameter may be, for example, a temperature signal which indicates a situation with respect to the current operating state of the pump unit 10. An excessively high pump temperature can thus be detected and processed by the controller 30 and the valves 11 and/or 12 can be actuated (103) in a suitable manner. Subsequently, the driving force F of the pump unit 10 may be reduced, for example_ATo cope with overheating of the pump unit 10 and the attendant damage to the pump unit 10. The order of the method steps shown is not mandatory. The method steps may be performed in a different order, but may alternatively be performed in parallel with each other.

By the high-pressure fuel pump and the associated method described above by the driving force F on the pump unit 10_ACan extend the functional freedom of the existing active valves 11 and/or 12. The resistance in the pump unit 10 can thus be adjusted within a specific critical operating range in the following manner: at a driving force F_AThe inhomogeneities or fluctuations in the neutralization and/or in the drive belt or drive train, for example, can be varied or reduced to permissible levels.

With the invention, critical operating states can be identified and appropriate countermeasures can then be initiated. The inhomogeneity of the drive force is detected at its generation region, if possible, so that no costly signal amplifiers or signal filters are required. By actuating at least the valve 11, the hydraulic load of the pump unit 10 can be adjusted in such a way that the drive force F can be reduced without additional components_AIs not uniform. A "hydraulic load" is understood in this case to be a hydraulic load of the pump unit 10, which hydraulic load is generated by the conveying medium and its conveyance and is applied to the pump unit 10 during operation. Can be specifically influenced by actuating the valve 11 and/or other valvesThe hydraulic load.

Furthermore, dynamic oscillations in surrounding structural components, such as, for example, drive belts or drive chains, which are caused by inhomogeneities, are also detected. By means of the phase shift of the hydraulic consumer, the excitation of the vibrations can be influenced in a targeted manner and the occurrence of resonant vibrations can be prevented.

Further, the driving force F may also be acquired and monitored_AAverage value of (a). If the average value is above a predefined limit value, the presence of damage, an incorrect operating method or contamination in the pump unit 10 can be inferred. By actuating the at least one valve 11, damage at the pump unit 10 can be avoided or at least limited without using additional components. In the event of damage, the hydraulic load can be reduced to a minimum and the pump unit 10 can in this way be protected against total damage. Driving force F_AThe increased average value of (a) may also indicate, for example, the use of unspecified transport media.

Claims

1. A high-pressure fuel pump having:

a pump unit (10);

a drive unit (51) driven by a driving force (F)_A) -driving the pump unit (10);

valves (11, 12) with settable flow rates, which are hydraulically connected to the pump unit (10); and

a control unit (30) for determining the driving force (F)_A) And for being dependent on said driving force (F)_A) To control the flow of the valves (11, 12),

wherein the control unit (30) is configured for acquiring the driving force (F)_A) Wherein the control unit (30) is configured for dynamically adjusting the driving force (F) by controlling the flow of the valve (11, 12)_A) To compensate for said driving force (F)_A) The acquired inhomogeneity in (a).

2. According to the rightThe high-pressure fuel pump as claimed in claim 1, wherein the driving force (F) is derived from a currently required driving force of the pump unit (10)_A）。

3. The high-pressure fuel pump according to any one of claims 1 or 2, wherein the control unit (30) is configured to derive the driving force (F) from a combined characteristic curve of the pump units (10)_A）。

4. The high-pressure fuel pump according to claim 1 or 2, having a drive motor for deriving said driving force (F)_A) The first sensor unit (20).

5. The high-pressure fuel pump as claimed in claim 4, wherein the pump unit (10) is driven by a drive unit (51) via a shaft (13) with at least one cam (14), and the first sensor unit (20) derives the driving force (F) on the shaft (13) directly or indirectly_A）。

6. The high-pressure fuel pump according to claim 1 or 2, for obtaining said driving force (F)_A) While a second sensor unit (23) is utilized.

7. The high-pressure fuel pump as claimed in claim 6, wherein the second sensor unit (23) is arranged in a working space (16) of the pump unit (10) or is hydraulically connected with the working space (16).

8. The high-pressure fuel pump according to claim 7, wherein said second sensor unit (23) is a pressure sensor.

9. Drive force (F) for reducing a high-pressure fuel pump according to any one of the preceding claims_A) Wherein the high-pressure fuel pump has valves (11, 12) hydraulically coupled to a pump unit (10)) The method comprises the following steps:

acquiring (101) a driving force (F) in relation to a pump unit (10)_A) Is determined by the information of (a) a,

processing (102) acquired information about driving force (F)_A) And is provided with

According to the acquired driving force (F)_A) To operate (103) at least one valve (11, 12).

10. Method according to claim 9, wherein the information about the driving force (F) is derived at least partly from a combined characteristic curve or by measurement_A) The information of (1).

11. Method according to any of claims 9 or 10, wherein the provided information is related to the driving force (F)_A) Is compared with a predefined threshold value (41, 42).

12. Method according to claim 11, wherein the actuation of the at least one valve (11, 12) is only performed if a predefined threshold value (41, 42) is exceeded or fallen below.

13. Method according to claim 9 or 10, wherein the driving force (F) is derived from a currently required driving force of a pump unit (10)_A）。