WO2017060131A1

WO2017060131A1 - High-pressure fuel pump and method for reducing irregularities in the driving force of a high-pressure fuel pump

Info

Publication number: WO2017060131A1
Application number: PCT/EP2016/073019
Authority: WO
Inventors: Thomas Schmidbauer
Original assignee: Continental Automotive Gmbh
Priority date: 2015-10-05
Filing date: 2016-09-27
Publication date: 2017-04-13
Also published as: DE102015219153A1; DE102015219153B4; CN108138726A; KR20180059934A; CN108138726B

Abstract

The invention relates to a high-pressure fuel pump and to a method for reducing irregularities of the driving force of the high-pressure fuel pump having a pump unit. The high-pressure fuel pump comprises a pump unit, a drive unit which drives the pump unit by means of a driving force, a valve having an adjustable flow rate which is hydraulically coupled to the pump unit, and a control unit for determining the driving force and for controlling the flow rate through the valve in accordance with the driving force.

Description

description

High-pressure fuel pump and method for reducing nonuniformities in the driving force of a high-pressure fuel pump

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

Many modern vehicles use powerful fuel pumps. More recently, the classic fuel pumps have been replaced by improved high-pressure fuel pumps. The high-pressure fuel pumps deliver the fuel under increased pressure (up to 3000 bar in diesel engines) into the engine. This can improve the efficiency of modern engines. Due to the high pressures, however, there are more or less strong fluctuations and thus nonuniformities in the driving force of the high-pressure fuel pumps. These irregularities lead to vibrations that expand on surrounding components and place heavy mechanical loads on them. In the worst case, it may also come to a resonance in the high-pressure fuel pump or in one of the surrounding components and destroy them. The nonuniformities in the drive force are based on different resistance conditions in the interior of the high-pressure fuel pump. The driving force required by the pump can work back to the drive components of the high-pressure fuel pump, consequently, during the Pum ^¬ penbetriebes vary greatly (flow pulsation) and in the sequence. However, the high-pressure fuel pump is in

Normally driven with an approximately constant driving force. Consequently, during operation of the high-pressure fuel pump, there is a greater or lesser difference between the delivered driving force and the force actually required by the fuel pump. As a result, the above-described non-uniformities in the driving force. So far, the surrounding and adjacent components Therefore, a high-pressure fuel pump according to robust and thus designed heavy.

The object underlying the invention is to reduce the nonuniformities in the driving force of a high-pressure fuel pump.

The object is achieved by a high-pressure fuel pump having a pump unit, a drive unit that drives the pump unit via a driving force, a valve with adjustable flow rate, which is hyd ^¬ raulisch coupled to the pump unit, and a control unit for determining the driving force and Controlling the flow of the valve as a function of the driving force includes. The advantage is that a compensation of nonuniformities in the driving force can take place over a possibly already existing construction.

In one embodiment of the high-pressure fuel pump, the driving force can be determined from a currently required driving force of the pump unit. The use of the required driving force of the high-pressure fuel pump allows a genuine detection of the currently actually recorded driving force of the high-pressure fuel pump.

In one embodiment of the high-pressure fuel pump, the control unit can determine the driving force from a map of the pump unit. In this way, sensor units can be saved.

For example, the high-pressure fuel pump may be equipped with a first sensor unit for determining the driving force. This has the advantage that the non-uniformities can be detected near their place of origin.

According to a further exemplary embodiment of the high-pressure fuel pump, the pump unit can be driven via a shaft with at least one cam and the first sensor unit can determine the driving force directly or indirectly 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 determination of the driving force can be carried out by a second sensor unit. The driving force can alternatively be determined by the second sensor unit or the determination of the driving force redundant by the first and the second sensor ^¬ unit done.

In one exemplary embodiment of the high-pressure fuel pump, the second sensor unit can be arranged in a working space of the pump unit or can be hydraulically connected to the working space. Such an arrangement has the advantage that the sensor unit is not mounted in the vicinity of a movable component, for example the shaft. For example, the second sensor unit may be a pressure sensor. The technical advantage is that a pressure sensor can be inexpensively manufactured and used.

Further, the object is achieved by a method for reducing non-uniformities of a driving force of a high-pressure fuel pump, wherein the high-pressure fuel pump has a valve which is hydraulically coupled to a pump unit. The method comprises ascertaining information about the driving force of the pump unit, processing the ascertained information about the driving force, and controlling at least one valve as a function of the ascertained information about the driving force. The advantage is that a dynamic adaptation of the currently present irregularities in the driving force is made possible.

In one embodiment, the information about the driving force at least partially from a map or by Measurement can be determined. The information can thus be detected with high accuracy.

In a further embodiment, the information provided about the driving force can be compared with predefined threshold values. This has the advantage that the nonuniformities of the driving force can be classified and classified.

In a further example, the actuation of at least one valve may be performed only when a predefined threshold value is exceeded or undershot. The control of the valve is only carried out as soon as it makes sense technically.

For example, the driving force may be the momentarily required driving force of the pumping unit. The currently required driving force is particularly suitable for the unadulterated detection of the nonuniformity of the driving force.

Examples of the high-pressure fuel pump and method for reducing irregularities in a driving force of a pump unit below with reference to the Figures it ^¬ explained. The figures serve to illustrate fundamental aspects. The figures are not necessarily to scale, but wherein like reference characters designate the same or similar Kom ^¬ components each having the same or similar design or operation. 1 shows an exemplary force ^¬ high pressure fuel pump in a circuit diagram.

FIG. 2 shows in a circuit diagram the high-pressure fuel pump according to FIG. 1 in combination with a drive unit.

Figure 3 shows an exemplary force ^¬ high pressure fuel pump in a circuit diagram. FIG. 4 shows, in a circuit diagram, a further exemplary high-pressure fuel pump with a pumping unit and a sensor unit in the working space of the pumping unit. FIG. 5 shows in a diagram a progression of a drive force of the pump unit as a function of time and of predefined threshold values.

FIG. 6 shows a flow chart of an example

Method for reducing nonuniformities of

Driving force.

FIG. 1 shows a ^high- pressure fuel pump with a pump unit 10, which is designed to control a flow rate of a valve 11 and / or 12 via a controller 30. By flow may be understood to mean a flow rate per unit of time, a time duration for the flow or a time for the at least partial opening or closing of at least one valve 11 or 12. In the drive of the pumping unit 10, during operation, more or less strong fluctuations of the driving force F _A may occur. The

Fluctuations in the driving force F _A may be due, for example, to the changing internal resistances of the pump unit 10 during operation. Under the driving force F at ^¬ _A, for example, the currently required drive force of the pump unit 10 can (the force that can accommodate the pump unit 10 currently) be understood. The currently required driving force may be the driving force F _A , which is necessary so that the pumping unit 10 can promote a predefined flow rate.

When driving the pump unit 10, it may, depending on the type of power transmission, come to different high losses. In a drive via a belt transmission, for example, a part of the drive energy can be converted by the belt into heat. If the nonuniformities of the driving force F _{A are} detected on the drive unit 51, this can lead to only a part of the nonuniformities in the driving force F _A is detected, since possibly a proportion of the non-uniformities was compensated by the (cyclic) belt elongation. The control of the valves 11 and / or 12 by the controller 30 therefore depends considerably on which positions in the drive of the pump unit 10, the driving force F _{A is} determined. Therefore, for effective control of the valves 11 and / or 12 as the underlying drive force F _A, the currently required (or recorded) to ^¬ driving force of the pump unit can be used tenth For this purpose, the currently required driving force in the vicinity of the pump unit 10, in particular on the (drive) shaft 13 of the pump unit 51 can be determined. Disturbing influences by elasticities in the drive of the pumping unit 10 are thereby reliably reduced. In the description below the currently required (or recorded) to ^¬ driving force is called the driving force F _A.

The illustrated high-pressure fuel pump can mitigate the fluctuations in the driving force F _A by predefined activation of at least one valve 11 or 12, which is hydraulically connected to the pumping unit 10. A hydraulic connection can be understood to mean that the valves 11 and 12 are arranged in the circulation of the pumping unit 10 and can be flowed through by the same conveying medium which flows through the pumping unit 10. A controller 30 can process the information representing the drive force of the pump unit 10 and at least control the valve 11 and / or 12 in response to the information. As pumping unit 10, various pumps, such as positive displacement pumps or flow pumps can be used. Alternatively, the control of the described high-pressure fuel pump can also be used in blowers and compressors. Positive displacement pumps can be, for example, piston pumps, in particular reciprocating pumps,

Be diaphragm pumps or bellows pumps. For example, a high-pressure fuel pump can deliver diesel or gasoline at a pressure between 1500 bar and 3000 bar (diesel) and between 150 bar and 500 bar (gasoline). These pressure ranges may be referred to as high pressures in connection with a fuel pump.

For example, the drive force F _{A of} a pump unit 10, as shown in Figure 3 at regular intervals have a maximum 61 of the driving force F _A. Accordingly, a controller 30 can control at least the valve 11 and / or the valve 12 and adjust its flow in a suitable manner. For example, the flow rate of the valve 11 and / or the valve 12 can be increased to reduce the resistance in the pumping unit 10, which may arise through the valve 11 or the valve 12. As a result, the maximum 61 in the driving force F _{A of} the pumping unit 10 can be alleviated. Alternatively or additionally, the opening time of the valve 11 and / or the valve 12 can be adjusted. For example, the opening time may be shortened, lengthened, and / or the timing of closing and / or opening the valve 11 and / or the valve 12 may be varied. As a result, fluctuations in the driving force F _A can also be reduced. The same can also apply to a minimum 62 of the driving force F _A. Also in this case, the valve 11 and / or the valve 12 can be opened or closed by the controller 30 in a suitable manner. The flow rate can be controlled, for example, by a variable lift on the valve 11 and / or the valve 12. In addition, the controller 30 may be configured to control other valves in a suitable manner individually or in combination with the valves 11 and / or 12. As valves any type of valves can be used, such as check valves, check valves, pressure valves, pressure relief valves, throttle valves or directional control valves. The valves may also be controllable valves, such as solenoid valves. It can also be combined with different valves. The controller 30 may process the information representing the driving force F _A according to predefined algorithms. The information representing the driving force F _A will be described in the following description merely as information or Information about the driving force F _A denotes. It is irrelevant in what way the information about the driving force F _{A are} determined. The driving force F _A can be determined from a characteristic diagram of the pump unit 10. For example, the controller 30 may be constructed such that it is capable of determining the information about the driving force F _A from a previously stored map of the pumping unit 10. Alternatively, the driving force F _{A can} also be determined indirectly or directly via a measurement. For this purpose, for example, a first sensor unit 20 can be used which determines the driving force F _A during operation and forwards it to the controller 30. The first sensor unit 20 can determine the driving force F _A in various ways. It can be used, for example, capacitive, inductive or optical measuring method. In addition, any combinations of the aforementioned methods can be used. For example, it is also possible that the controller 30 activates a plurality of valves which are hydraulically connected to the pumping unit 10 and thus keeps the driving force F _A approximately constant. The control of the valves 11 and / or 12 can be effected, for example, hydraulically, electrically or pneumatically. In addition, a mechanical control is possible. A combination of different control methods is also conceivable.

Another example of a high-pressure fuel pump is shown in FIG. The drive unit 51 is used to drive the pump unit 10 and can be configured in various ways. The drive of the pumping unit 10 can be linear (for example by means of a linear drive) or via a rotary movement

(For example, via a camshaft) take place in conjunction with a rotary motor. In the example shown, the information about the driving force F _{A of} the pumping unit 10 can be determined via a first sensor unit 20, which is arranged here on the drive unit 51. The drive unit 51 can provide the driving force F _A for the pumping unit 10. The drive unit 51 can be connected directly or indirectly (via a transmission) to the pumping unit 10. FIG. 3 shows an example of a high-pressure fuel pump with a drive unit 51 acting via a rotational movement. In this example, the pump unit 10 is a piston pump. By means of a piston 15 moving linearly between two dead centers, a pumped medium can be conveyed through the pump unit 10 and subsequently to a destination for the pumped medium. A pump cycle may for example consist of a first and a second pump cycle. In the first pump cycle, the pumped medium can be sucked into the working space 16 of the pump unit 10 via a channel 52 in which a valve 11 can be located. Subsequently, the medium to be conveyed in the subsequent second pump cycle via a channel 53 in which a valve 12 may be located, promoted. This process can run cyclically and thus ensure a continuous flow. As conveying media, all types of fluids such as gases and liquids, for example

Fuel or oil can be used for an internal combustion engine. In the example shown, the piston of the piston pump is pressed by a spring-loaded plunger 17 against a cam 14. The plunger 17 is connected on a first side with a piston 15 and mounted on the second side opposite the first side rolling on the cam 14. The cam 14 is in turn fixedly connected to the shaft 13. The shaft 13 is mounted in a housing and can protrude out of the housing at least on one side. At the end of the shaft 13, which protrudes from the housing of the pump unit 10, for example, a pulley or a gear can be attached.

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, an inductive or an optical sensor unit. The first sensor unit 20 can in this example be composed of a transmitter unit 21 and a receiver unit 22. Both the transmitter unit 21 and the receiver unit 22 can be an active and / or a passive component. The driving force F _{A of} the pump unit 10 determined by the first sensor unit 20 can in this case also be derived from a torque, which can rest against the shaft 13. The torque is due to the fact that the piston of the pump unit 10 can not be moved linearly but via a rotational movement of the shaft 13. In the case of a linear drive, which drives the pump unit 10 directly (as briefly described above), a force instead of a torque can be determined. Depending on the type and arrangement of the drive unit 51, under the drive force F _{A, in} addition to a force or a torque, any other parameter suitable for determining the drive force F _A can also be understood.

The determination of the driving force F _{A will} be explained below with reference to an inductively operating first sensor unit 20. The transmitter unit 21, which in turn may consist of several individual transmitters, may be arranged radially on the shaft 13 and rotate during operation with the shaft 13. The receiver unit 22 may be arranged in the housing while maintaining a predefined distance to the transmitter unit 21. As soon as a transmitter of the transmitter unit 21, for example a magnet, runs past a receiver unit 22 during operation, a voltage pulse is induced in the receiver unit 22. This voltage pulse can be interpreted by the controller 30 and further processed. Unit in dependence on the number of transmitters in the transmitter unit 21 and the receivers in the receiver 22, the resolution accuracy of the required driving force F at ^¬ _A can be adjusted. In this case, an increase in the number of transmitters in the transmitter unit 21 and receivers in the receiver unit 22 can lead to a higher resolution accuracy. It is also possible to arrange the receiver unit 22 on the shaft 13 and, in turn, to arrange the transmitter unit 21 in the housing. It is also possible that the

High-pressure fuel pump further comprises sensor units, which are also adapted to at least partially ^¬ infor mation on the driving force F _A to be determined.

In another example of a high-pressure fuel pump, shown in FIG. 4, the high-pressure fuel pump has a second sensor unit 23, which is hydraulically connected to the working space the pump unit 10 may be connected. The second sensor unit 23 may in this example be a pressure sensor and be mounted in addition to or instead of the first sensor unit 20. As already described in connection with the first sensor unit 20, the second sensor unit 23 may be a sensor unit operating according to various methods and may comprise one or more receivers and transmitters. The pressure sensor passes signals on the currently prevailing pressure conditions in the working chamber 16 of the pump unit 10 to the controller 30. The pressure can be measured in predefined time intervals. In particular, the measurement intervals can be adapted to the drive force F _A and the rotational speed of the pump unit 10. In a pump cycle (a suction and an exhaust stroke), the pressure may be measured, for example, thirty times, in particular twenty times. FIG. 4 also shows that the controller 30 may be integrated in an engine control unit (ECU = Electronic Control Unit), for example for a motor vehicle.

In the controller 30, the determined driving force F _{A can be} compared with predefined threshold values 41 and / or 42. The controller 30 may be configured such that activation of the valve 11 and / or of the valve 12 takes place only when a predefined threshold value 41 and / or a predefined threshold value 42 are exceeded and / or exceeded. The control pulses can be reduced in this way to a necessary degree, wherein the threshold values 41 and 42 can be adapted to the load capacity of the surrounding parts in the drive unit 51. With correct interpretation of the

Thresholds 41 and 42, an overload of the components of the drive unit 51 is not expected. FIG. 5 shows a function 43 of the drive force F _A over the time with the threshold values 41 and 42. FIG. 5 shows that the function 43 of the drive force F _A slightly exceeds the threshold value 41 in this example at specific times. The same applies to the falling below the threshold 42.

FIG. 6 is a flow chart of a method for reducing non-uniformities of the driving force F _A of FIG Pump unit 10 shown. The exemplary flowchart comprises the determination (101) of information about the drive force F _{A of} the pumping unit 10. This can be understood to mean all conceivable ways which result in the controller 30 receiving information about the drive force F _A at the pumping unit 10. For example, the information about the at ^¬ driving force F _A can be taken from a characteristic field 10 of the pumping unit. Alternatively, the information may be obtained from any suitable function and measuring device. The information on the driving force F _{A of} the pump unit 10 can then be further processed (102). Further processing in this context means an interpretation of the information of the driving force F _A , as well as the output of the control signals for the valves 11 and / or 12. Such interpretation can for example take place in that the information obtained about the driving force F _A of the pumping unit are set with further inputs, such as user inputs ^¬, or other suitable parameters in the context of the tenth A suitable parameter may be, for example, a temperature signal, which are 10 information on the current operation ^¬ state of the pumping unit. Too high a pump temperature can thus be detected and processed by the controller 30 and the valves 11 and / or 12 are controlled in a suitable manner (103). As a result, for example, the driving force F _{A of} the pump unit 10 can be reduced in order to counteract overheating of the pump unit 10 and a concomitant destruction of the pump unit 10. The sequence of process steps shown is not mandatory. The Ver ^¬ method steps may be performed in a different order, or also parallel to one another.

By virtue of the above-described high-pressure fuel pump and the associated method, the functional degree of freedom of existing active valves 11 and / or 12 can be expanded by processing a driving force F _A on the pump unit 10. As a result, in certain critical operating ranges, the resistances in the pump unit 10 can be such be adapted that the resulting irregularities or fluctuations in the driving force F _A and / or for example in drive belts or drive chains can be changed or reduced to an acceptable level.

With the invention, critical operating conditions can be detected and appropriate countermeasures can be initiated as a result. Nonuniformities of the driving force are detected as far as possible at the area of origin, so that no complex signal amplifier or signal filters are necessary. By controlling at least the valve 11, the hydraulic load of the pump unit 10 can be adjusted so that the nonuniformities of the driving force F _A without zu ^¬ additional components can be mitigated. In this context, a hydraulic load is understood to mean the hydraulic load of the pump unit 10, which is generated by the pumped medium and its delivery and rests against the pump unit 10 during operation. This hydraulic load can be selectively influenced by controlling the valve 11 and / or other valves.

In addition, the resulting from the nonuniform dynamic vibrations in the surrounding components, such as drive belts or drive chains, recognized. By a phase shift of the hydraulic load, the excitation of the vibration can be selectively influenced and a generation of a resonant vibration can be prevented.

Furthermore, an average value of the drive force F _A can also be determined and monitored. If this mean value is above a predefined limit value, it is possible to conclude that damage has been caused, incorrect equipment or impurities in the pumping unit 10. By controlling at least one valve 11, without the use of additional components, damage to the pump unit 10 can be avoided or at least limited. The hydraulic load can be reduced to a minimum in the event of damage and the pump unit 10 are protected in this way from total destruction. An elevated one Average value of the driving force F _A can also indicate, for example, the use of an unspecified pumped medium.

Claims

claims

1. High-pressure fuel pump with:

a pumping unit (10);

a drive unit (51) which drives the pump unit (10) via a driving force (F _A );

an adjustable flow valve (11, 12) hydraulically coupled to the pumping unit (10) and a control unit (30) for determining the driving force (F _A ) and controlling the flow rate of the valve (11, 12) in response from the driving force (F _A ).

2. High-pressure fuel pump according to claim 1, wherein the driving force (F _A ) from a momentarily required driving force of the pump unit (10) is determined.

3. High-pressure fuel pump according to one of claims 1 or 2, wherein the control unit (30) for determining the driving force (F _A ) from a characteristic field of the pump unit (10) is formed.

4. High-pressure fuel pump according to one of the preceding claims, with a first sensor unit (20) for determining the driving force (F _A ).

5. high-pressure fuel pump according to one of the preceding

Claims in which the pump unit (10) via a shaft (13) with at least one cam (14) of the drive unit (51) is driven ^¬ and the first sensor unit (20) the driving force (F _A ) directly or indirectly on the Shaft (13) determined.

6. High-pressure fuel pump according to one of the preceding claims, for determining the driving force (F _A ) with a second sensor unit (23).

7. High-pressure fuel pump according to one of the preceding claims, wherein the second sensor unit (23) in a working space (16) of the pump unit (10) is arranged or with the working space (16) is hydraulically in communication.

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

9. A method for reducing non-uniformities of a driving force (F _A ) of a high-pressure fuel pump, wherein the

High-pressure fuel pump having a valve (11, 12) which is hydraulically coupled to a pump unit (10), comprising:

Determining (101) information about the driving force (F _A ) of the pump unit (10),

Processing (102) the information obtained for

Driving force (F _A ), and

Actuation (103) of at least one valve (11, 12) as a function of the ascertained information about the driving force (F _A )

10. The method of claim 9, wherein the information about the driving force (F _A ) are determined at least partially from a map or by measurement.

11. The method according to any one of claims 9 or 10, wherein the information provided about the driving force (F _A ) with predefined threshold values (41, 42) are compared.

12. The method of claim 11, wherein the driving of at least one valve (11, 12) only when exceeding or falling below a predefined threshold value (41, 42) is performed.

13. The method according to any one of claims 9 to 12, wherein the driving force (F _A ) is determined from a momentarily required driving force of the pump unit (10).