Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
  • F01L9/20—Valve-gear or valve arrangements actuated non-mechanically by electric means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
  • F01L9/40—Methods of operation thereof; Control of valve actuation, e.g. duration or lift
  • F01L2009/4086—Soft landing, e.g. applying braking current; Levitation of armature close to core surface
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
  • F01L9/40—Methods of operation thereof; Control of valve actuation, e.g. duration or lift
  • F01L2009/4098—Methods of operation thereof; Control of valve actuation, e.g. duration or lift relating to gap between armature shaft and valve stem end

Definitions

• An electromagnetic actuator for actuating a gas exchange valve on a piston internal combustion engine essentially consists of two spaced apart
• Electromagnets the pole faces of which face each other and between which an armature acting on the gas exchange valve to be actuated is guided back and forth against the force of at least one return spring between an open position and a closed position for the gas exchange valve.
• One of the electromagnets serves as a closing magnet, by means of which the gas exchange valve is held in the closed position against the force of the opening spring, while the other electromagnet serves as an opening magnet, by means of which the gas exchange valve is held in the open position against the force of the associated closing spring via the armature.
• the arrangement is such that the armature is in a central position between the two pole faces in the rest position.
• the armature When the two electromagnets are energized alternately, the armature then comes to bear against the force of a return spring on the pole face of the electromagnet that is energized and thus trapped. If the holding current is switched off at the respective holding electromagnet, the armature is accelerated by the force of the return spring in the direction of the other electromagnet, which is subjected to a correspondingly high capture current during the armature movement, so that after the overshoot over the The center position of the armature comes into contact with the magnetic force against the force of the return spring associated with the electromagnet now catching.
• the electromagnetic actuator is controlled as a function of the operating data of the piston internal combustion engine available to the engine control, essentially the load requirement and the speed. If, for example, the gas exchange valve is in its closed position, ie the armature is in contact with the closing magnet, the control is essentially time-dependent, ie via the engine control system taking into account the crankshaft position and the parameters from the load specification, which each indicate the opening and closing times for the gas exchange valve. Switching off the relatively low holding current initiates the start of the armature movement, so that the catching current on the catching electromagnet can be switched on at a predeterminable time interval after switching off the holding current. The time interval can be determined using previous empirical data or theoretical data.
• the magnetic force increases progressively as the armature approaches the pole face of the capturing electromagnet with constant current, while the force of the return spring acting in the opposite direction only increases linearly.
• the armature moves in the final phase shortly before hitting the pole face of the capturing electromagnet with increasing acceleration, so that there is a hard impact of the armature on the pole face, which is disadvantageous in many respects, for example due to the body - and airborne sound excitation and the resulting noise.
• an attempt is made to reduce the capture current shortly before the armature strikes the pole face of the respective capturing electromagnet by means of a corresponding control, the approach of the armature being detected by means of a sensor system.
• the invention is based on the object of creating a method which enables a much more precise control of an electromagnetic actuator and avoids noise.
• a method for actuating an electromagnetic actuator for actuating a gas exchange valve on a piston internal combustion engine which has two electromagnets arranged at a distance from one another, between which an armature acting on the gas exchange valve against the force of at least one Return spring is movably guided back and forth between the pole faces of the two electromagnets with a predetermined stroke between the open position and the closed position of the gas exchange valve, wherein a control current is applied alternately to the electromagnets and the stroke of the armature during its movement by a sensor system one pole face to the other pole face is detected, so that, depending on the detected actual values of the stroke of the armature, the capturing electromagnet is controlled via the control with regard to the current supply so that the armature is at a predeterminable distance area to the pole face of the electromagnet that is catching each other with a speed moves and that at the end of the stroke the energization of the capturing electromagnet is guided so that the armature
• actual values of the armature stroke includes at least the detection of the respective end position of the armature and, if applicable, the detection of its speed and its acceleration.
• the speed can either be recorded directly or derived from the derivation of the path over time resulting from the position detection, as well as the acceleration.
• armature stroke in the sense of the method according to the invention is defined by the path of the gas exchange valve between its closed position and its open position, without the armature being released from its support on the shaft of the gas exchange valve due to valve play.
• the distance between the two pole faces is greater than the armature stroke by approximately the amount of valve clearance.
• the physical peculiarities of the actuator namely both its individual mechanical peculiarities and the peculiarities that change due to the operation of the piston internal combustion engine, are taken into account.
• the first phase there is only an "observation" of the armature movement, by means of which the energetic starting position of the armature movement is detected, which is essentially predetermined by the actual time of detachment from the pole face and by the force of the return spring accelerating the armature, on the one hand, and that counteracting frictional forces and gas pressure forces.
• the armature occur during detachment necessarily add nor the energy losses in the mechanical system by acting in the opposite direction, residual field.
• These negative electromagnetic forces can be reduced by using a vortex low current armature and / or by applying a current of different polarity, which generates a repulsive magnetic field acting on the armature.
• the anchor has its highest speed when passing through the middle layer. In this area, external influences such as cylinder pressure, friction influences or actuator parameters can affect the armature movement.
• the actual values of the armature stroke are detected at least in the respective end position via the sensor system, then there is the possibility, towards the end of the armature stroke, of actuating the capturing electromagnet with respect to the current supply in such a way that the armature is in a predeterminable distance range , a so-called “target window”, moves with a speed going towards “zero” and a speed going towards “zero” and at the end of the armature stroke the holding current is guided so that the armature is kept floating without contact with the pole face.
• a so-called “target window” moves with a speed going towards "zero” and a speed going towards “zero” and at the end of the armature stroke the holding current is guided so that the armature is kept floating without contact with the pole face.
• the movement phase that begins when the target window is reached is characterized by a low anchor speed and a high force effect of the catching magnet.
• a controlled guidance of the armature against the force of the return spring up to the end of the armature stroke is possible via the energization of the capturing magnet, so that it is ensured that the armature is held at a preferably small distance from the pole face.
• the electromagnets can be energized by regulating the voltage applied to the capturing magnet.
• a voltage control instead of a current control, the necessary control interventions can be effected much more precisely and quickly, since even after the voltage is switched off, the current drops relatively slowly and, accordingly, the current increases relatively slowly when a voltage is switched on.
• the voltage and power supply is expediently taken from the electrical system of the piston internal combustion engine.
• Fig. 7 the stroke when stopping the actuator from the closed position.
• FIG. 1 shows an electromagnetic actuator 1 for actuating a gas exchange valve 2, which essentially consists of a closing magnet 3 and an opening magnet 4, which are arranged at a distance from one another and between which an armature 5 counteracts the force of return springs, namely an opening spring 7 and a closing spring 8 is guided to move back and forth.
• a gas exchange valve 2 which essentially consists of a closing magnet 3 and an opening magnet 4, which are arranged at a distance from one another and between which an armature 5 counteracts the force of return springs, namely an opening spring 7 and a closing spring 8 is guided to move back and forth.
• the arrangement is shown in the closed position, specifically in the "classic" arrangement of the opening spring and the closing spring.
• the closing spring 8 acts directly via a spring plate 2.2 connected to the shaft 2.1 of the gas exchange valve 2.
• the guide rod 11 of the armature 5, which can be divided into itself, is separated from the shaft 2.1.
• a so-called valve clearance VS is present.
• the opening spring 7 is in turn supported on a spring plate 11.1 on the guide rod 11, so that under the action of the opening spring 7 in the position shown, the guide rod 11 is pressed onto the stem 2.1 of the gas exchange valve 2. If there is valve lash compensation, the distance VS corresponds to the intended levitation range. It is also possible to provide only a single restoring spring at the location of the opening spring 7, which is designed such that it builds up a corresponding restoring force each time the armature 5 swings over the central position. A separate closing spring 8 is therefore not required. In such an arrangement, however, the guide rod 11 must be connected to the shaft 2.1 of the gas exchange valve via a corresponding coupling element, which transmits the reciprocating movement of the armature to the gas exchange valve 2 in the same way.
• the closing spring 8 and the opening spring 7 are usually designed so that in the rest position, d. H. when the electromagnet is not energized, the armature 5 is in the middle position. From this middle position, armature 5 with its gas exchange valve 2 must then be swung at start.
• the electromagnets 3 and 4 of the actuator 1 are energized via a current controller 9.1 assigned to them, which is controlled by an electronic motor controller 9 in accordance with the specified control programs and as a function of the operating data supplied to the motor controller, such as speed, temperature, etc. While it is fundamentally possible to provide a central current regulator for all actuators on a piston internal combustion engine, it is expedient for the method according to the invention if each actuator is assigned its own current regulator which is connected to a central voltage supply 9.2 and which is controlled by the engine control. tion 9 is controlled.
• a sensor 10 is assigned to the actuator 1, which enables the detection of the armature functions.
• the sensor 10 is shown schematically here.
• the stroke of the armature 5 is detected, so that the respective armature position can be transmitted to the motor controller 9 and / or the current regulator 9.1.
• appropriate computing operations can then be used.
• the armature speed and / or the acceleration can be determined so that depending on the armature position and / or in dependence on the armature speed and / or the acceleration, the energization of the two electromagnets 3, 4 is controlled in the catching phase and in the holding phase can be.
• the senor 10 does not necessarily have to be assigned to a probe rod 11.1 connected to the armature 5. It is also possible to laterally assign a correspondingly designed sensor to the armature 5 or also to arrange corresponding sensors in the region of the pole face of the respective electromagnet.
• the current regulator 9.1 also has corresponding means for detecting current and voltage for the respective electromagnet 3 and 4 and for changing the current profile and the voltage profile.
• the actuator 1 of the motor controller 9 can then be used as a function of predefinable operating programs, possibly based on corresponding characteristic diagrams
• Gas exchange valve 2 can be controlled fully variably, for example with regard to the start and end of the opening hours. Control with regard to the height of the opening stroke or the number of opening strokes during the closing time can also be controlled. Small opening strokes from the closed state due to "slowly floating" detachment and "slowly floating" fitting of the valve are also possible.
• the flow of the closing magnet 3 is guided via the current regulator 9.1 in such a way that the armature is held at a short distance from the pole face of the closing magnet 3 with ideal current supply so that the armature 5 is still in contact with its guide rod 11 stands with the stem 2.1 of the gas exchange valve.
• the magnetic force generated by the holding current of the closing magnet 3 is ideally guided so that the force in the contact surface between the guide rod 11 and the valve stem 2.1 goes to "zero" and thus the gas exchange valve 2 is pressed onto its valve seat with the full force of the closing spring 8.
• the remaining gap between the pole surface of the closing magnet 3 and the facing surface of the armature 5 corresponds approximately to the valve clearance VS.
• Fig. 2 in relation to the embodiment.
• Fig. 1 shows schematically with the line 12 the course of the armature movement over a full movement cycle.
• curve 12 shows the course of the stroke of the armature 5 as a function of the time for a full valve clearance, starting from the closed position shown in FIG. 1 through the open position back to the complete closed position.
• the line 13 indicates the position of the pole face of the closing magnet 3 and the line 14 indicates the position of the pole face of the opening magnet 4.
• the holding current of the two electromagnets 3 and 4 is guided so that the armature 5 is floating in front the respective pole face is held.
• FIG. 3 shows the area marked I in FIG. 2 on a larger scale.
• Line 13 again shows the position of the pole face of the closing magnet.
• the curve branch 12 shows the course of the movement from the floating stop position of the armature after the stop current has been switched off. From the course it can be seen that when the holding current is switched off, the armature movement begins without adhesive time and without superimposed vibrations.
• the curve branch 15 shows the course of the stroke of the armature 5 in comparison when the closing magnet 4 is so energized that the armature comes to rest on the pole face.
• the armature After switching off the Haltestrro ung, which takes place at the same time as for the curve 12, the armature is still held by the closing magnet 4 during a so-called gluing time until the force of the decelerating magnetic field is so low that the restoring force of the opening spring 7 is sufficient to move the anchor 5.
• the armature with its guide rod 11 strikes the end of the valve stem 2.1 after overcoming the valve clearance VS, the total mass of armature and gas exchange valve then being further accelerated after an initial bouncing process, depending on the spring mass A vibration remains superimposed on this path of movement.
• the area II in FIG. 2 is then shown on a larger scale, namely the movement of the floating armature in the open position.
• the gas exchange valve By means of a current supply between a lower and an upper holding current level with a variable frequency and a variable clock ratio according to the specification of the floating regulator 9.1, the gas exchange valve also vibrates to a small extent as a result of the holding magnet force thereby acting pulsatingly on the armature 5, whereby the spring force causes the Guide rod 11 rests firmly on the free end of the valve stem 2.1. This slight back and forth movement of the valve in its open position is irrelevant to the flow processes.
• the armature 5 first moves under the force of the closing spring 8 again in the direction of the pole face of the closing magnet 3.
• the catching closing magnet 3 is then energized accordingly to the after exceeding the middle position by a corresponding magnetic force, the now overcome more opposing force of the opening spring 7.
• the movement is guided so that after an initial acceleration via a corresponding energization of the catching closing magnet 3, the speed and also the acceleration depending on the armature position detected by the sensor 10 become "zero", so that the armature 5 is again floating in the Distance is kept in front of the pole face of the closing magnet 3.
• Line 16 in FIG. 5 shows the course of the armature stroke until the gas exchange valve 2 is placed on its valve seat (point 17).
• the method described above also offers the possibility of moving the gas exchange valves out of the respective end position, be it the closed position or the open position, in a “guided” stroke course into the central position when the piston internal combustion engine is stopped. This is shown in FIG. 7.
• Line 19 in FIG. 7 shows the course of the stroke when the holding current is switched off, which applies both to an armature resting on the pole face of the holding electromagnet and to an armature which is suspended at a distance from the pole face of the holding electromagnet. Since, after the holding current has been switched off, the armature 5 is only exposed to the acceleration force of the associated return spring, the armature is moved at high speed in the direction of the central position, which it initially overshoots due to the kinetic energy against the force of the other return spring, so that the Armature and thus the gas exchange valve comes to rest only after the central position has been overswound several times due to the lack of magnetic force of the other electromagnet. This multiple overshoot of the middle position leads to a considerable noise development both in the air inlet tract and in the gas outlet tract.
• the signal from sensor 10 can be recalibrated by a one-time absolute assignment of the valve clearance measurement, for example as a function of temperature. This value is then used to put the relative detection of the stroke in relation to the contact point between valve and armature in an absolute frame.
• a sensor calibration can be carried out by the resulting holding current level in the floating state, since this current height is essentially a function of the distance between the armature and the pole face in the floating position.
• Fluctuations in the maximum speed and thus the flight time due to the "location blur of the end position" can over the known system parameters, such as a corresponding control vibration characteristic in the end positions are compensated.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Valve Device For Special Equipments (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Magnetically Actuated Valves (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)

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• 2000
  • 2000-05-25 EP EP00945689A patent/EP1101016B1/fr not_active Expired - Lifetime
  • 2000-05-25 US US09/744,694 patent/US6427651B1/en not_active Expired - Fee Related
  • 2000-05-25 JP JP2001500104A patent/JP2003500601A/ja active Pending
  • 2000-05-25 AT AT00945689T patent/ATE224505T1/de not_active IP Right Cessation
  • 2000-05-25 WO PCT/EP2000/004772 patent/WO2000073635A1/fr active IP Right Grant

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