EP2724011A1

EP2724011A1 - Method and device for operating a fuel delivery device of an internal combustion engine

Info

Publication number: EP2724011A1
Application number: EP12718201.2A
Authority: EP
Inventors: Uwe Richter; Burkhard Hiller; Joerg Kuempel; Rainer Winkler; Heiko Roth
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2011-06-22
Filing date: 2012-05-02
Publication date: 2014-04-30
Anticipated expiration: 2032-05-02
Also published as: CN103635680A; KR101898880B1; EP2724011B1; KR20140035947A; DE102011077991A1; WO2012175247A1; JP2014517212A; US9777662B2; US20140311456A1; JP5959636B2; CN103635680B

Abstract

The invention relates to a method for operating a fuel delivery device (1) of an internal combustion engine, in which method an electromagnetic actuating device (9) of a volume control valve (10) is switched such as to set a delivery volume, wherein an intensity of an energy that is supplied to the electromagnetic actuating device (9) for switching purposes, in particular of a current (I) supplied to the electromagnetic actuating device (9) and/or a level of a voltage applied to the electromagnetic actuating device (9), depends at least intermittently on a rotational speed (72) of the internal combustion engine.

Description

description

title

METHOD AND DEVICE FOR OPERATING A FUEL CONVEYOR DEVICE OF AN INTERNAL COMBUSTION ENGINE

State of the art

The invention relates to a method according to the preamble of claim 1,

and a computer program and a control and / or regulating device

the independent claims.

Quantity control valves, for example, in a fuel delivery of a

Internal combustion engine, are known from the market. Quantity control valves are

generally electromagnetically operated and are often an integral

Part of a high-pressure pump of the fuel delivery device. The

Quantity control valve controls the pumped to a high-pressure accumulator ("Rail")

Fuel quantity from where fuel to the injectors of the

Internal combustion engine is passed. One with a valve body of

Quantity control valve coupled armature can be moved by magnetic force.

The valve body - usually an inlet valve of the high pressure pump - can against

strike a valve seat, or lifted off the valve seat

become. As a result, an amount of fuel of the internal combustion engine can be regulated

become. A patent publication in this field is, for example, EP 1

042 607 B1. Disclosure of the invention

The problem underlying the invention is achieved by a method according to claim 1 and by a computer program and a control and / or regulating device according to the independent claims. advantageous

Further developments are specified in subclaims. For the invention important features can be further found in the following description and in the drawings, the features both alone and in

different combinations may be important for the invention, without being explicitly referred to again.

The inventive method has the advantage that a quantity control valve (metering device) of a fuel delivery device - in particular while an internal combustion engine is operated at medium or low speeds - can be controlled with comparatively low electrical energy. The

Operating noise of the quantity control valve can be lowered and fatigue strength increased.

The invention relates to a method for operating a

Fuel delivery device of an internal combustion engine, in which an electromagnetic actuator of a arranged in an inlet to a delivery chamber of the fuel delivery device quantity control valve is switched to adjust a flow rate. For this purpose, the electromagnetic actuator for each switching operation in which an armature is to be moved in the direction of a stroke stop, by means of the drive

Energy supplied. For example, the switching of the quantity control valve occurs twice, three times or even four times during one revolution of one

Camshaft of the internal combustion engine. For safe switching of the

Quantity control valve and to achieve short switching times even at the highest possible speed of the camshaft or the internal combustion engine comparatively high energies are required.

The invention is based on the consideration that at speeds below the maximum speed, the requirement for a short shift time is correspondingly less critical. Thus, according to the invention, the strength of the electromagnetic

Actuating device for switching energy supplied, in particular one the current supplied to the electromagnetic actuator and / or a height of a voltage applied to the electromagnetic actuator, at least temporarily made dependent on a speed of the camshaft or the internal combustion engine, namely, that it is lower at low speeds than at large.

An embodiment of the method provides that the energy only during a suit phase during which the armature of the electromagnetic

Actuator is moved from a first to a second position, depends on the speed of the internal combustion engine. The tightening phase requires a lot of energy to achieve a required short switching time. Thus, the inventive dependence of the control of the speed of the internal combustion engine during the tightening phase is particularly efficient. The activation of the electromagnetic actuating device during a holding phase following the tightening phase can take place essentially independently of the rotational speed.

Furthermore, it is provided that the energy is increased with increasing speed, wherein the relationship is monotonous. This takes into account that the movement of the armature must generally be faster according to the speed. Preferably, this is done using a continuous and monotone characteristic.

In particular, it is provided that the energy is controlled such that the quantity control valve can be safely switched within a time interval provided for a respective speed. The time interval is generally greater for lower speeds than for higher speeds, and is sized so that the quantity control valve can operate correctly. The resulting temporal scope is used according to the invention to a

To extend the duration of the armature at low speeds within the respective time interval. This requires less energy.

An embodiment of the method provides that the current and / or the voltage for controlling the electromagnetic actuator are clocked. For example, the electromagnetic

Actuation device by means of an electronic switch several times during the Anzugsphase and / or the holding phase of the armature to an operating voltage and turned off again. A set duty cycle thus determines the average current during the control. The duty cycle is adjusted so that the average current in accordance with the invention depends on the speed of the internal combustion engine.

Preferably, an actuation of the electronic switch takes place depending on a respective lower and upper current threshold. When the current flowing through a coil of the electromagnetic actuator current is lower

Current threshold falls below, then the electronic switch is closed, and thus the coil is switched to the operating voltage. As a result, the current flowing through the coil - and thus caused magnetic force - increases continuously. If the current flowing through the coil exceeds the upper current threshold, then the electronic switch is opened, thus shutting off the coil from the operating voltage. This reduces the current flowing through the coil - and correspondingly the magnetic flux

Power - continuous. In general, the current thresholds used for the pull-in phase and the hold phase are different.

Alternatively to the use of current thresholds, it is also possible to control the electromagnetic actuating device by means of a "pre-controlled" pulse-width-modulated voltage, the determining parameters being set in advance for at least one control. According to the invention, these parameters are adjusted so that the strength of the energy supplied to the electromagnetic actuator for switching at least temporarily from the speed of the

Internal combustion engine depends.

The method is particularly easy to carry out if it by means of a computer program on a control and / or regulating device

("Control unit") of the internal combustion engine is performed. In a preferred

Design is the establishment of the controller by loading the computer program with the characteristics of the independent

Computer program claim from a storage medium. Under the

Storage medium is understood as far as any device that the

Computer program in stored form contains. Hereinafter, exemplary embodiments of the invention will be explained with reference to the drawings. In the drawing show:

Figure 1 is a simplified diagram of a fuel delivery of a

Internal combustion engine;

Figure 2 is a sectional view of a high-pressure pump of

A fuel delivery device together with a quantity control valve and an electromagnetic actuator;

Figure 3 is a timing diagram of a control of the electromagnetic

Actuating means;

FIG. 4 shows a diagram of a starting current and a starting time over a rotational speed of the internal combustion engine; and

Figure 5 is a simplified block diagram to supplement the method.

The same reference numerals are used for functionally equivalent elements and sizes in all figures, even in different embodiments.

FIG. 1 shows a fuel delivery device 1 of an internal combustion engine in a greatly simplified representation. From a fuel tank 3 is fuel via a suction line 4, by means of a pre-demand pump 5, via a low-pressure line 7, and one of an electromagnetic actuator. 9

("Electromagnet") actuated quantity control valve 10 of a (not further explained here) high-pressure pump 1 1 fed. Downstream is the

High-pressure pump 1 1 connected via a high-pressure line 12 to a high-pressure accumulator 13 ("common rail"). Other elements, such as valves of the high pressure pump 1 1, are not shown in the figure 1. The electromagnetic actuator 9 is controlled by a control and / or regulating device 16, on softer a computer program 18 is executable. It is understood that the quantity control valve 10 may be formed as a unit with the high pressure pump 1 1. For example, that can

Quantity control valve 10 a forced openable intake valve of

Be high-pressure pump 1 1. Alternatively, the quantity control valve 10 may also have an actuating device other than the electromagnet 9, for example a piezoactuator.

During operation of the fuel delivery device 1, the prefeed pump 5 promotes fuel from the fuel tank 3 into the low-pressure line 7. The quantity control valve 10 controls the quantity of fuel supplied to a working space of the high-pressure pump 11 by moving an armature of the electromagnet 9 from a first to a second position - and vice versa - is moved. The

Quantity control valve 10 can thus be closed and opened.

Figure 2 shows a partial sectional view (longitudinal section) of the high pressure pump 1 1 of the fuel conveyor 1 together with the quantity control valve 10 and the electromagnetic actuator 9. The illustrated arrangement comprises a housing 20 in which in the drawing in the upper area of the electromagnetic actuator 9, in the middle Area the quantity control valve 10, and in the lower part of a delivery chamber 22 are arranged together with a piston 24 of the high-pressure pump 1 1.

The electromagnetic actuator 9 is arranged in a valve housing 26, and comprises a coil 28, an armature 30, a pole core 32, an armature spring 34, a rest seat 36 and a stroke stop 38. The rest seat 36 represents the first position of the armature 30, and the stroke stop 38 represents the second position of the armature 30. The armature 30 acts by means of a coupling element 40 a valve body 42. In the drawing above the valve body 42, an associated sealing seat 44 is arranged. The sealing seat 44 is part of a pot-shaped housing element 46, which encloses inter alia the valve body 42 and a valve spring 48. Seal seat 44 and valve body 42 form the inlet valve of the high-pressure pump 1 1.

Shown in Figure 2 is the de-energized state of the electromagnetic actuator 9. In this case, the armature 30 by means of the armature spring 34 in the drawing pressed down against the retirement seat 36. About the

Coupling element 40 is thereby acted upon by the valve body 42 against the force of the valve spring 48, whereby the inlet valve or the

Quantity control valve 10 opens. As a result, a fluidic connection between the low-pressure line 7 and the delivery chamber 22 is produced.

In the energized state of the electromagnetic actuator 9, the armature 30 is magnetically attracted by the pole core 32, whereby the coupling element 40 connected to the armature 30 is moved upward in the drawing. This can - with appropriate fluidic pressure conditions - the

Valve body 42 are pressed by the force of the valve spring 48 against the sealing seat 44, and thus close the intake valve or the quantity control valve 10. This can be done, for example, when the piston 24 in the delivery chamber 22 performs a working movement (in the drawing above), wherein fuel via an open check valve 60 in the

High pressure line 12 can be promoted.

The opening or closing of the quantity control valve 10 takes place in

Dependency of several sizes: First, depending on the force exerted by the armature spring 34 and the valve spring 48 forces. Second, depending on which in the

Low pressure line 7 and the delivery chamber 22 prevailing fuel pressure. Third, depending on the force of the armature 30, which is essentially determined by a currently flowing through the coil 28 current I. In particular, the current I - again depending on the respective fuel press - affect the timing of opening or closing of the valve body 42 and thus substantially control the amount of fuel to be delivered.

Figure 3 shows a timing diagram of a control of the quantity control valve 10. In the coordinate system shown in the drawing are currents 11 (solid) and 12 (dashed), which via the coil 28 of

electromagnetic actuator 9 flow, applied over a time t. A double arrow 62 indicates the energization for a

Tightening phase and a double arrow 64 indicates the energization for a holding phase of the armature 30 of the electromagnetic actuator 9. During the tightening phase, the armature 30 by magnetic force of the

Retirement seat 36 is moved to the stroke stop 38. During the holding phase will the armature 30 is held in position by a generally smaller magnetic force on the stroke stop 38. The course of the flow 11 will first be described below, which at a comparatively high rotational speed 72 (cf. FIG. 4) of the internal combustion engine is used to control the electromagnetic actuating device 9.

At a time tO the tightening phase begins, wherein the current 11

increases relatively quickly and is clocked from a time t1 a to a mean value 66a. At a time t2, the energization begins for the

Holding phase, wherein the current 11 is clocked by an average value 68. The mean value 68 is smaller than the mean value 66a. At a time t3, the drive is stopped, whereby the current 11 is rapidly reduced to zero.

At a lower speed 72 of the internal combustion engine is the

Electromagnetic actuator 9 is driven by the current 12, that is, switching thresholds (not shown), which control the switching on and off of the current 12 during the tightening phase, are set lower with respect to switching thresholds of the current 11. This results in a correspondingly smaller mean value 66b for the course of the current 12 during the tightening phase. Thus, the required energy during the tightening phase is also smaller and an operating noise when striking the armature 30 at the stroke stop 38 is reduced. At the same time, a tightening duration of the armature 30 is at the same time lengthened, the time difference between t2 and t0 being increased and thus the tightening phase 62 extended, but without the correct one

Function of the quantity control valve 10 to affect.

The switching thresholds (not shown) determining the courses of the currents 11 and 12, or the resulting average values 66a and 66b, are each selected such that a secure abutment of the armature 30 on the stroke stop 38 and thus reliable switching of the quantity control valve 10 in all Operating cases is possible. Due to the during the tightening phase in the average smaller current 12 of the armature 30 is accelerated compared to the current 11 with a lower force and suggests a correspondingly delayed. This will be explained in more detail below with reference to FIG. FIG. 4 shows a coordinate system in which average values 66 of a current I flowing through the coil 28 during the starting phase and associated tightening durations 70 are plotted linearly over a rotational speed 72 of the internal combustion engine. The tightening duration 70 characterizes the period of time from the beginning of energizing the coil 28 at the time t0 until the first striking of the armature 30 on the stroke stop 38. The mean values 66 are determined in the present case by support points 74 which, for example, in a characteristic diagram of the control and / or regulating device 16 of the internal combustion engine can be stored. The average values 66 of the current I characterize-in particular when the coil 28 is switched to a constant source voltage during the starting phase-also an energy which is supplied to the electromagnetic actuating device 9 during the starting phase.

It can be seen that the mean values 66 of the current I monotonously increase as the rotational speed 72 increases. Because the piston 24 of the high pressure pump 1 1 is also moved in response to the speed 72, the possible period for movement of the valve body 42 and the armature 30 is correspondingly smaller, so critical. This circumstance is countered by the tightening durations 70 which decrease with greater energization, in a suitable manner. This is done as already described above such that a secure switching of the

Quantity control valve 10 at each speed 72 is enabled.

FIG. 5 shows a simplified flow chart for controlling the

electromagnetic actuator 9. The illustrated method is preferably by means of the computer program 18 in the control and / or

Regulating device 16 of the internal combustion engine performed. In a first block 76, the illustrated procedure begins, wherein the current speed 72 of the

Internal combustion engine is determined. In a second block 78, two interpolation points 74 are read from a characteristic field on the basis of the determined rotational speed 72.

Thereafter, interpolation is performed between these two interpolation points 74 to determine a respective mean value 66 exactly matching the speed 72. From the average 66 suitable switching thresholds (without reference numerals) for the switching on and off of the current I are determined. In a third block 80, the determined switching thresholds are used, the electromagnetic actuator 9 or the coil 28 to drive during the tightening phase of the armature 30. The method of FIG. 5 can be repeated cyclically.

Claims

claims

1 . Method for operating a fuel delivery device (1) of a

Internal combustion engine, in which an electromagnetic actuation device (9) of a quantity control valve (10) is switched to set a delivery rate, characterized in that a strength of one of the electromagnetic actuation device (9) for switching energy, in particular one of the electromagnetic

Actuator (9) supplied current (I) and / or a level of a voltage applied to the electromagnetic actuator (9) voltage, at least temporarily depends on a speed (72) of the internal combustion engine.

2. The method according to claim 1, characterized in that the energy only during a tightening phase (62), during which an armature (30) of the electromagnetic actuator (9) is moved from a first to a second position, of the rotational speed (72). the internal combustion engine depends.

3. The method according to claim 1 or 2, characterized in that the

Energy with increasing speed (72) is increased, the relationship is monotonous.

4. The method according to at least one of the preceding claims, characterized in that the energy is controlled such that the

Quantity control valve (10) can be switched within a time interval provided for a respective speed (72).

5. The method according to at least one of the preceding claims, characterized in that the current (I) and / or the voltage are clocked. Computer program (18), characterized in that it is programmed to carry out a method according to at least one of the preceding claims.

Control and / or regulating device (16) of an internal combustion engine, characterized in that it comprises a memory on which a

Computer program (18) according to claim 6 is stored.