EP1387927A1

EP1387927A1 - Electromagnetic control device

Info

Publication number: EP1387927A1
Application number: EP02735357A
Authority: EP
Inventors: Heinz Leiber
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-05-14
Filing date: 2002-05-14
Publication date: 2004-02-11
Also published as: US20040169988A1; WO2002092971A1

Abstract

The invention relates to an electromagnetic control device for actuating a valve of an internal combustion engine. A locking system is provided in order to maintain the valve in at least one of its end positions and in at least one intermediate position.

Description

Electromagnetic actuator

The invention relates to an electromagnetic actuating device with the features of the preamble of claim 1.

Such an actuator is known from DE 197 12 062 AI.

It is known that in internal combustion engines at low speeds or low load, combustion can be improved and thus consumption reduced if the valves are not opened completely but the valves are operated in the partial stroke. Controlling the control devices so that the associated valves are operated in the partial stroke means stopping of the valve with a relatively large air gap, which is only possible with relatively large electrical currents, thereby reducing the consumption savings.

The invention has for its object to design the actuating device so that this additional energy consumption does not occur.

This object is solved by the features of claim 1.

The holding system can act directly on the armature and hold it in place, but can also act on the valve, in particular its stem or an actuating part present between the armature and valve, and thereby hold the armature indirectly.

The holding system can be a locking system, as is known in principle from DE 197 12 062A1, or a clamping system, as will be described in more detail later.

The invention is applicable to actuators in which the armature performs a linear movement, such as. B. from DE 195 21 078 AI known, as well as those in which the armature performs a pivoting movement.

As will be shown later, the invention can be used particularly advantageously with a twin arrangement of two or more valves. In the twin application, the valves are arranged in a row. The actuators, which actuate the valves and have pivotable armatures, are arranged alternately to the left and right of the valves. Here the active part of the locking system, namely at least one electromagnet and possibly. also a force directed against the force of this electromagnet, e.g. B. a spring force or a permanent magnet system for the two valves of a twin can be used. This arrangement can also be used without partial stroke training.

The partial stroke, e.g. B. 1mm can be achieved with the invention with very low power. The locking system can be designed in such a way that it works almost wear-free in connection with the control of the main magnet.

Electromagnetic actuators in the magnetic circuit are optimized for low holding power. Small air gaps and low iron losses are therefore necessary. Therefore avoiding saturation of the iron circle. The power of the magnet required to catch the armature is not very demanding on the iron circuit, since even with a relatively large air gap the magnet coil is switched from larger currents to less (= flooding) in order to prevent the magnet from having too much excess force (= speed) crashes into its end position.

To start the system, a conventional system must be moved from the middle position to the end position by periodic oscillation and / or large current intensities, which places a great strain on the vehicle electrical system. This is critical when starting the engine, since the starter's electrical system load is already high. When using the holding system according to the invention, the anchor can be held in an end position or in the intermediate position, so that it goes into operation immediately when starting. You can e.g. B. to achieve different partial strokes of z. B. 0.5 and 1mm provide two corresponding intermediate positions of the actuating device. With appropriate training, the retention system works almost wear-free. The electrical energy consumption of the retention system is very low.

The invention is explained in more detail using the exemplary embodiments of the drawing.

Show it:

Fig. 1 shows an embodiment in which the

Armature swiveled and the valve is held in place by locking

Fig. 2 shows the same embodiment with the detent lever raised

Figure 3 is a diagram in which the valve is temporarily placed in a partial stroke position.

Fig. 4 shows an embodiment in which the valve is held by a clamp.

1 shows two actuating devices 1 and 2 which act on valve stems 9a and 10a arranged one behind the other. They are arranged on different sides of the valves and also offset from one another in the direction of the paper planes. The actuating device 1 and accordingly also the actuating device 2 have a lever 3 which is pivotably mounted at 4 and in which the armature of the actuating device is integrated. Two electromagnets 5 and 6, each with a winding 5a or 6a, are provided in each actuating device. Two opposing spring forces act on the lever 3, namely a valve spring 7 and a torsion bar 8 which acts on the bearing. Due to the action of these springs 7 and 8 and the electromagnets 5 and 6, the lever 3 is between the two on the two adjusting devices 1 and 2 end positions shown pivoted back and forth and thereby brought the valve 9 into the two end positions shown with I and III, namely valve fully open (III) and valve closed (I).

In the end position I, the lever 3 and thus the valve 9 are held in place by a locking system. This is the case in the actuating device 1 shown on the left.

Each locking system has a locking lever 11 and 11 ^λ which is pivotably mounted at 11a and which is pressed to the left or right by a spring 12. The lever 3 is somewhat narrower at its free end and there it has counter-detents 3a into which the end of the detent lever 11 snaps. In the drawing, the locking lever 11 is drawn into the lowest counter-locking, which corresponds to the closed valve. A second counter-latching mechanism 3a is shown right next to it. When the locking lever 11 is locked in this counter locking, the lever 3 is held in an intermediate position and the valve 9 is in the partial stroke position II. To unlock the locking lever 11 is a

Rast (electro) magnet 13 provided. If its winding 13a is energized, the latching lever is pulled out of the latching mechanism to the right and the lever 3 is moved downward by the force of the spring 8. With the help of

Catch magnet 6 (shown on the actuating device 2), the second end position III is reached, in which the valve is kept open.

Here, the lever 3 formed on the nose 3a ^Λ locked in an opening 11b on the locking lever 11 and holds the lever in this second end position (as shown for the adjusting device 2) without further energization of the trapping magnet fixed. The prerequisite is, of course, that the energization of the locking magnet has been ended beforehand, so that the nose 3a ^{λ of} the lever 3 rests against the free end of the locking lever 11 and can finally snap into place.

In FIG. 2, which otherwise corresponds to FIG. 1, the unlatched state is shown for the latching lever 11. By corresponding energization of the locking magnet, this unlocking position of the locking lever can be maintained until the desired locking position is approximately reached, thus largely avoiding the grinding of the nose 3a ^λ on the locking lever 11, which results in a substantial freedom from wear.

It is for wear and tear and limited

Magnetic force of the detent magnet necessary to briefly energize the corresponding electromagnet 5 or 6 to unlock the detent lever, that is, for. B. to unlock the locking lever 11 from the position shown on the left in FIG. 1, the electromagnet 5. The drawing shows the peculiarity that the locking magnet 13 and the spring 12 are responsible for the locking levers 11 and 11 ^{λ of} the two actuating devices 1 and 2 shown, which form a so-called twin. The two actuators can work in parallel or separately. Should z. B. only one valve work, the locking magnet is switched as described. The closing magnet 5, or the corresponding magnet of the actuating device 2, is not energized in the case of the valve, which is not working, ie is to remain closed.

The pressing force of the spring 8 transmitted from the armature lever 3 to the lever 11 is so great that the magnetic force of the locking magnet 13 is not sufficient to unlatch it, ie. H. Trigger movement of lever 1.

3, the sequence of the

Anchor movement described once in the two end positions I and III and once from position I in the partial stroke position II and back. In FIG. 3a the stroke of the armature or the valve S _v , in FIG. 3b the stroke of the locking lever S _R , in FIG. 3c the current profile i _{R of} the locking magnet, in FIG. 3d the current i _Mi in the closing magnet 5 and FIG. 3e shows the current i _{M2 of} the opening magnet 6 over time.

Up to T ₀ , the valve is "closed" in position I and is held in this position by the latching lever 11. In order to unlatch the valve 9, the latching current i _{R is} switched on at Ti and the magnet 5 is energized a little later at T ₂ . The latter in order to facilitate the unlatching and to make it wear-resistant. From T ₃ the locking lever 11 moves and unlatching occurs at T _Ö . The force of the torsion spring 8 makes this Valve accelerates. At T ₄ the current of the

Opening magnet 6 turned on, with the help of that

Valve is brought into the other end position III.

The procedure described with full stroke is typical for high speeds with short opening times, so that a detent is not very effective in order to save electrical power.

The current of the closing magnet is then reduced to a value that is sufficient for holding. At T ₅ , the holding current i _{M2 is} switched off and the valve 9 is now accelerated in the opposite direction by the valve spring 7. At T _ß the catching current i _M ι of the magnet 5 is switched on, which brings the valve into the other end position I and holds it with a holding current until the latching lever 11 is engaged.

During the movement of the valve from position I to the open position III and while the valve 9 remains there and also over part of the jerking movement, namely up to T ₆ , the detent magnet 13 is acted upon with a small current clocked in the drawing, which current The end of the locking lever 11 lifts off the lever 3 and prevents the parts from rubbing against one another. At T ₆ , the current of the locking magnet is reduced in such a way that the locking lever 11 now abuts the armature 3. T ₇ the Latch begins. The movement of the

Locking lever when snapping has a reaction on the current ι _R (at T ₇ ). Since the locking position is a fixed position, this current change (because of the mutual induction initiated by the armature movement) can at least be used as an auxiliary signal for determining the position, e.g. B. can be used to calibrate a position sensor.

After a longer closing time of the valve 9, in which there is no current consumption in any of the magnets, the unlatching is initiated at T _x ^λ or T ₂ ^λ . In contrast to the course described above, when the partial stroke is initiated, the current of the magnet 5 is only switched off briefly in order to enable the valve movement. The current of the magnet is regulated in such a way that the armature lever moves slightly beyond the locking position II. The latching current i _{R is} switched off at the time Tβ, so that the latching lever 11 can reach the counter latching 3a and holds the valve in the partial stroke position II. Then the current i _M ι of the magnet 5 is regulated so that the lever 3 at T ₉ with less

Impact speed touches the locking lever 11.

Shortly before the valve closing time T _s , the closing magnet is switched on again at T ₀ , which leads to a movement of the armature lever 3 and the valve 9 until the valve closes and then until the armature lever 3 strikes the yoke 5. This movement is also regulated so that there are low landing speeds for the valve 9 and the armature lever 3. The locking magnet does not have to be energized during this process. As a result of the spring force, the locking lever moves into the locking position I. Subsequently, in (11), the closing magnet is subjected to a controlled current reduction in order to achieve a soft placement of the armature lever on the locking lever. This partial stroke sequence is advantageous at low speeds or low loads and is used in these situations.

Fig. 4 shows an embodiment in which the valve stem is held in place of locking by clamping, which is possible in any position of the valve.

The drawing shows the structure of a clamping element. A piezo actuator 21 is embedded in a housing 22 which has cutouts for the connections 23 and 23a. The force of the piezo actuator acts on this housing 22 and a transmission part 24, which is supported on a clamping part 25. This is set off accordingly in the clamping zone and consists of a hard material, e.g. B. carbide. The clamping is shown in the upper half of the picture and the freewheel is shown below. On the side opposite the part 25, the second clamping area is designed as an extension 22a of the housing 22. Here too, the clamping zone 22b has hard material. The clamping force is generated via two opposing springs 26 and 26a, which act on the housing 22 and the transmission part 24. The elongated stem 27 of a valve is clamped here. This is also hard in the clamping zone 27a. Acts on the valve stem

Actuating element 28 of an electromagnetic actuator, which is not shown. The valve is coupled to a valve spring 30 via a spring plate 29.

In the idle state, that is to say without actuation of the piezo actuator 21, the clamping parts 22, 22a and 22b or 24, 25, 25a are due to the action of the springs 26 and 26a in the clamping position shown above. If the clamping is now to be released, the piezo actuator 21 is energized and expands in accordance with its physical effect. The expansion acts on the housing 22 as an action force and at the same time via the transmission part 24 on the clamping part 25 and 25a as a reaction force. Thus, the clamping element is spread and an air gap is created between the valve stem 27 and the clamping zones 22a and 25a. The spring 30 and the second spring force (not shown) of the electromagnetic valve drive then move the valve in one of the two directions depending on the position of the valve. The clamping is therefore independent of the direction. This condition is shown in the drawing below.

The clamping element must be supported on both sides.

The electromagnetic actuator is suitable for this.

The support 31 is shown hatched in principle above. Since the clamping element has to take up tolerances, a floating bearing is advantageous with a small clearance S. So that there is only a small amount of friction

Tolerance adjustment arises are the housing 22 and that

Clamping part 25 provided with sliding elements 32. In the

A valve stem can also be clamped

Angular tolerances occur. To avoid this, a kalottenfor ige bearing 33 on the clamping part 25 axially

Valve axis are used. This is outlined below and dashed above.

Claims

claims

1) Electromagnetic actuating device (1) for driving a valve (9) of an internal combustion engine, with at least one electromagnet (5, 6) and a displaceably mounted armature which, without actuation of the at least one electromagnet (5, 6), by two oppositely directed spring forces ( 4, 7) is held in an intermediate position and which is moved back and forth between the poles of the at least one electromagnet (5, 6) by the interaction of the at least one electromagnet (5, 6) and the spring forces (4, 7), wherein the armature movement is transmitted to the valve (9) and which is temporarily or indirectly retained at least after reaching end positions at least in the vicinity of the pole faces, this retention at least in the end position (I) associated with the closed valve by a retention system (11 to 13), characterized in that preferably in the vicinity of the end position assigned to the closed valve (position I) at least one intermediate position (II) is provided and that in this at least one intermediate position (II) the same retaining system (11 to 13) holds the anchor.

2) Electromagnetic actuator according to claim 1, characterized in that the holding system is a locking system (11 to 13). 3) Electromagnetic actuating device according to claim 2, characterized in that a latching lever (11) is provided for latching per armature, which is movable by the force of an electromagnet (latching magnet 13) against a second force (12) acting on it and which, provided on the anchor or a part (3) connected to it, counter-catches (3a, 3a ^Λ ) can be snapped into place.

4) Electromagnetic actuator according to claim 3, characterized in that the second force

Spring (12) is.

5) Electromagnetic actuator according to claim 3, characterized in that the second force is formed by permanent magnets.

6) Electromagnetic actuating device according to one of claims 3 to 5, characterized in that the locking lever (11) and the second force acting on it (12) are such that the locking lever (11) on the armature or a part connected to it (3rd ) and that the locking lever can be lifted off the armature or part (3) by the force of the locking magnet (13).

7) Electromagnetic actuating device according to claim 6, characterized in that during the armature movement of the locking lever (11) is lifted up to near the desired locking position of the armature or part (3).

8) Electromagnetic actuator according to one of claims 2 to 7, characterized in that for Unlatching each of the at least one electromagnet (5) is also controlled.

9) Electromagnetic actuating device according to one of claims 2 to 8, characterized in that the energization of the at least one electromagnet (5,

6) is regulated in such a way that the counter detents (3a, 3a ^λ ) touch the detent lever at a low speed.

10) Electromagnetic actuator according to one of claims 2 to 9, characterized in that the

Latching movement for detecting the position of the armature is at least also used.

11) Electromagnetic actuating device, in particular according to one of claims 2 to 10, characterized in that when the valves (9) are arranged in a row, alternating electromagnetic actuators (1 and 2) arranged to the left and right thereof, which the valves (9) by a Actuate pivoting movement, two adjacent actuating devices (1 and 2) is assigned a locking magnet (13).

12) Electromagnetic actuator according to claim 1, characterized in that the retaining system is a clamping system (21 to 26).

13) Electromagnetic actuating device according to claim 12, characterized in that the clamping system includes clamping means (22, 22a, 22b; 24, 25, 25a) and an electrically controllable actuator (2) which actuates the clamping means and which actuates a Undergoes a change in length, which is transmitted to the clamping means, the clamping means consisting of two displaceably mounted clamping parts (22, 22a, 22b; 24, 25, 25a) acting on the part (7) from opposite directions, to which in

Spring forces (26, 26a) directed towards the part (27) act and that the change in length of the actuator (21) is transmitted to the two clamping parts (22, 22a, 22b; 24, 25, 25a) in the sense of removing the clamping parts from one another.

14) Electromagnetic actuating device according to claim 13, characterized in that the actuator is a piezo actuator (21).

15) Electromagnetic actuating device according to claim 13 or 14, characterized in that the clamping means are made of hard material at least at the zones (22a, 25a) which directly effect the clamping.

16) Electromagnetic actuator according to one of claims 13 to 15, characterized in that at least the zone (27a) of the part (27) on which the clamping acts consists of hard material.

17) Electromagnetic actuator according to one of claims 13 to 16, characterized in that the clamping parts (22, 22a, 22b; 24, 25, 26) are floating.

18) Electromagnetic actuating device according to one of claims 13 to 17, characterized in that the clamping parts (22, 22a, 22b; 24, 25, 26) are at least partially mounted in spherical caps (33). 19) Electromagnetic actuator according to one of the

Claims 12 to 18, characterized in that sliding elements (32) are provided for the mounting of the clamping parts (22, 22a, 22b; 24, 25, 26).

20) Electromagnetic actuator according to one of the

Claims 1 to 19, characterized in that the holding system (11 to 13) acts on the valve or on an actuating part arranged between armature or valve (9).