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

Definitions

• the present invention relates to a method of controlling an electromagnetic actuator of a thermal engine valve such as a motor vehicle engine.
• electromagnetic valve actuators which conventionally comprise elastic means and electromagnetic means for actuating the movable member between two extreme positions respectively corresponding to the open position of the valve and to the closed position of the valve.
• the elastic means generally comprise a spring associated with the movable member to bias the latter resiliently in its extreme open position and a spring associated with the valve stem to resiliently bias the latter in its closed position and to bias elastically the movable member towards its extreme closing position.
• the electromagnetic means generally comprise an electromagnet supplying and / or holding the movable member in the extreme open position and an electromagnet for supplying and / or holding the movable member in the extreme closed position .
• the electromagnet is often associated with a permanent magnet in order to limit the consumption of one electromagnet. The arrival of the movable member in its extreme closed position in which it is in contact with the armature of one corresponding electromagnet generates noise.
• the movable member and the valve are not connected to each other and there is a game commonly called “distribution game" between the movable member and the valve when the movable member is in the extreme closed position and the valve is correctly pressed against its seat by the spring associated with it.
• the distribution clearance varies during operation of the engine, in particular as a function of temperature, and also during the life of the engine, in particular as a function of the wear of the valve and the various components of the actuator. valve.
• the distribution clearance may vary from one actuator to another depending on the manufacturing tolerances thereof.
• Stopping the movable member in the range of the distribution set is difficult and there is a risk that the movable member is stopped while the movable member is still in contact with the tail of the valve preventing the latter to be properly applied against his seat.
• An object of the invention is to provide a means for optimizing the operation of the actuator.
• a control method of a thermal engine valve actuator comprising a movable member for cooperating with a tail of the valve, permanent magnet electromagnetic means associated with resilient means for moving the movable member between an extreme closed position and an extreme open position of the valve, the method comprising the steps of:
• the position control of the electromagnetic means from a setpoint position in the previously determined play range makes it possible to stop the movable member precisely in the desired position and allows an adaptation of the operation of the actuator for example to operating conditions of the engine.
• the setpoint position is the intermediate position for which the electrical control parameter has a minimum value.
• Maintaining the movable member in position is then provided at least in part by the permanent magnet, which allows to limit the consumption of electromagnetic means.
• the set position is the intermediate position corresponding to a minimum distance between the movable member and the valve stem.
• the invention is here described in application to the actuation of a valve 1 of a heat engine bearing the general reference 2.
• the valve 1 has a shank 3 and is mounted on a cylinder head 4 of the engine 2 to slide between a closed position in which the valve is applied against a seat 5 of the cylinder head 4 and an open position in which the valve is detached from the seat 5 of the cylinder head 4.
• the valve is actuated between these two positions via an actuator generally designated 6 mounted on the cylinder head 4 of the heat engine 2.
• the actuator comprises a body 7 in which is mounted to slide a movable member generally designated 8 comprising a rod 9 having a first end 10 arranged to bear on a free end of the tail 3 of the valve 1 and a second end 11 secured to a pallet 12 received in a housing 13 of the body 7 to slide parallel to the rod 9.
• the body 7 incorporates, in a manner known per se, electromagnetic means 14, 15 for moving the movable member 8.
• the electromagnetic means 14 comprise, in a manner known per se, an electromagnet of attraction of the pallet 12 towards a position called the extreme position of closing the valve and an electromagnet of attrac- the pallet 12 to a position called the extreme open position of the valve which open on two opposite faces of the housing 13 of the body 7.
• Each electromagnet comprises a coil wound on a frame to which is associated in known manner a magnet permanent.
• the permanent magnet ensures all or part of the maintenance of the pallet in the corresponding position.
• the pallet 12 is here in contact with the armature of the electromagnetic means 14, 15 when it is in the corresponding extreme position.
• the electromagnetic means 14, 15 are controlled in a manner known per se by non-represented servocontrol means from a setpoint current and a moving speed of the movable member 8. This servo mode is known in itself.
• the servo means are also arranged to allow servo-control as a function of a position command. This slaving can be ensured by the engine control unit which also operates a speed signal of the pallet 12 obtained by derivation of a position signal provided by a position sensor 16 of the rod 9.
• the position sensor 16 is for example a Hall effect sensor known in itself.
• the actuator also comprises, in a manner known per se, elastic displacement means.
• the elastic displacement means comprise in a known manner in itself a spring 17 interposed between a face 18 of the body 7 and a shoulder 19 of the rod 9 to recall the pallet 12 in the extreme open position and a spring 20 interposed between a face 21 of the yoke 4 and a shoulder 22 of the valve stem 3 to return the valve 1 in the closed position.
• the actuator, the cylinder head 4 and the valve 1 are arranged in such a way that when the pallet 12 is in the extreme closed position and the valve 1 is applied against its seat 5, there is a clearance j or clearance between the first end 10 of the rod 9 and the free end of the valve stem 3.
• the method according to the invention starts with the phase of determining the game j during operation of the engine.
• the method according to the invention comprises the step of controlling the electromagnetic means 14, 15 to move with a substantially constant speed the movable member 8 from its extreme closed position to its extreme open position.
• the speed of movement of the movable member can be kept constant up to the extreme opening position or over a distance greater than a maximum possible clearance taking into account the geometric characteristics of the actuator, the valve and the cylinder head.
• the method comprises the step of obtaining values of the target current for intermediate positions of the movable member during the displacement of the movable member 8 from the extreme closed position to the extreme open position and the step of detecting an intermediate position of the movable member 8 for which the setpoint current undergoes a sudden change.
• the setpoint current is supplied by the servo-control means (but it could be measured or detected) and the intermediate positions of the movable member 8 are provided by the position sensor 16.
• the setpoint current is then related to the intermediate positions of the movable member 8.
• the detection of the intermediate position for which the setpoint current undergoes a sudden change is preferably made from the derivative of the reference current with respect to the position of the parameter. 12.
• this derivative is shaped into a curve, the curve has peaks at the intermediate position corresponding to the meeting point of the movable member 8 and the valve stem 3.
• the method then comprises the step of selecting as setpoint one of the intermediate positions in the game j as a function of desired performance of the actuator.
• the selected target position is the intermediate position in which the supply current of the electromagnetic means 14 is zero (the attraction force of the corresponding permanent magnet compensates for the effort of the spring 17) or as low as possible (maximum attraction force of the permanent magnet).
• the selected target position is the intermediate position corresponding to a minimum distance separating the rod 9 of the tail 3.
• the set position becomes the closed position of the pallet in which the rod 9 is detached from the tail 3 of the valve 1 held in abutment against its seat 5 by the spring 20.
• the electromagnetic means can be controlled to first bring the movable member 8 gently to the intermediate position determined above to bring the movable member 8 into contact with the valve stem 3, then accelerate the movable member 8 once it bears against the tail of valve.
• the electromagnetic means can be controlled to first bring the movable member 8 quickly to the intermediate position corresponding to the beginning of the clearance j to have a quick closing of the valve, then gently move the movable member 8 in the closed position to limit the noise of the contact of the pallet 12 with the electromagnet 14.
• the determination of the game j and intermediate positions is preferably renewed periodically, for example every second.
• the clearance j can be determined with different modes of operation depending on the engine operating mode and the engine speed.
• the determination of the play can be carried out for a displacement of the movable member towards the extreme open position as described above or towards the extreme position of closure.
• the moving speed of the movable member will be kept substantially constant, for example from a median intermediate position of the pallet.
• the electromagnetic means can be controlled from another electrical characteristic such as a set voltage.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Valve Device For Special Equipments (AREA)
• Magnetically Actuated Valves (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=36694297

Family Applications (1)

Country Status (6)

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Family Cites Families (7)

• 2005
  • 2005-11-25 FR FR0511938A patent/FR2893975B1/fr not_active Expired - Fee Related
• 2006
  • 2006-11-14 WO PCT/FR2006/002514 patent/WO2007060309A1/fr active Application Filing
  • 2006-11-14 US US12/091,612 patent/US20090178631A1/en not_active Abandoned
  • 2006-11-14 JP JP2008541782A patent/JP5421592B2/ja not_active Expired - Fee Related
  • 2006-11-14 EP EP06831113A patent/EP1951994A1/de not_active Withdrawn
  • 2006-11-14 KR KR1020087003416A patent/KR101337778B1/ko not_active IP Right Cessation
• 2011
  • 2011-11-18 US US13/299,867 patent/US8443771B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

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