RO125407A2 - Electromagnetic device for valve actuation - Google Patents

Abstract

The invention relates to an electromagnetic device for the actuation of the valves of a heat engine. According to the invention, the device comprises a pre-polarized electromagnet consisting of two fixed magnetic cores (S1 and S2), namely an internal core and an external core, some axially and/or transversally divided permanent magnets (MP) being placed therebetween and having some coils (B1 and B2) located on both parts of the magnets (MP), so that, depending on the direction of the current through said coils (B1 and B2), the magnetic field is strengthened at one end and weakened at the other end and attracts one of the discs (D1 and D2) with an increased force, said disc being integral with a valve by means of a rod (T), thereby producing the displacement of the mobile equipment, which consists of the two discs (D1 and D2), the rod (T) and the valve, to one of the extreme positions; the supply of the coils (B1 and B2) with a current opposing to the direction of the current having generated the current position allows one of two springs (R1 and R2) to remove the mobile equipment from the current position and to move it to the opposite position or to the central balance point.

Description

STATE OFFICE FOR INVENTIONS AND TRADEMARKS [j Patent Application ^! K _ir <3I '· 1 · aouoi?> I «iiiiauicenoBnao: iaaoniiaaoa« a, aqsB' Date of deposit 2 8 IUL. 2008

Electromagnetic valve actuator

The invention relates to an electromagnetic device for actuating valves in heat engines.

In order to drive the valves to the heat engines, the camshaft actuators actuated by the crankshaft of the heat engine by means of belts or timing chains are known. This method has the disadvantage of a fixed connection between the position of the cams and that of the pistons regardless of speed and the required torque on the shaft. Therefore the operation of the heat engine is optimal only at a certain speed and a certain torque. At any time, half of the number of valves are closed, which causes high pressures in the cylinders to be created at start-up, which causes a substantial increase in starting torque. The wear and tear of the cams and the distribution system over time requires their permanent maintenance.

Also for the purpose of operating valves on heat engines are known camshaft actuators with longitudinally variable profile arranged on a shaft which can move axially by means of mechanically or electromechanically operated devices. The camshaft is also coupled to the crankshaft of the heat engine by means of belts or timing chains. This method has the disadvantage of a limited correlation of the opening and closing angle of the valve with the speed and load of the heat engine, high torque required to start the heat engine and permanent maintenance of the distribution system.

In order to drive the valves to the heat engines, actuators with rotary electric servomotor and mechanical system for transforming the rotational movement into a translational movement similar to the cam-tachet principle are known. The main disadvantage of the method is the use of the tangential electromagnetic force to produce the torque of the servomotor which leads to a high volume of the device and a high energy consumption.

Also for the purpose of actuating the valves to the thermal engines, the actuators with electromagnet and permanent pre-polarization magnet are known [1]. The disadvantage of these devices is the variation of the coil inductance with the position which makes it difficult to control the valve landing. When the ferromagnetic disk is at one end, the inductance reaches the maximum value and the time constant of the electrical circuit is high, increasing the release time of the valve.

In order to drive the valves to the heat engines, actuators with a linear servomotor [2] with permanent magnets are known. The disadvantage of this solution is that it requires several phases powered by power electronics, the dispersion of the permanent magnet field is high due to the use of a large number of poles and can not increase the magnetic induction in the air gap by concentrating the magnetic flux, permanent magnets can be demagnetized the magnetic field produced by the coils.

Also for the purpose of actuating the valves to the thermal motors, actuators with pre-polarized electromagnet with permanent magnet are known whose field is orthogonal to the magnetic field produced by the coils [3]. The disadvantage of these devices is the dependence of the thickness of the mobile magnetic disk on the length of the stroke, which increases its weight, which limits the acceleration of the mobile equipment and its response speed. The permanent magnet is directly exposed to the electromagnetic forces exerted between it and the mobile disk producing vibrations, noise and reduced reliability.

0-2008-00585

1 -07 * 2008

The technical problem solved by the invention consists in actuating the valves of the heat engines by means of a pre-polarized electromagnet with the help of a permanent magnet.

The solenoid valve actuator for heat engines eliminates the above disadvantages by using an electromagnet powered by a static converter, thus allowing the independent actuation of each valve after an optimal path corresponding to each operating point of the heat engine (any pair of doublets - mechanical torque of the heat engine) because the movement of the valve is done on the basis of a control program and not on the basis of a predetermined mechanical profile. The timing belt or timing chain is no longer required. When starting the heat engine, all valves will be opened until the crankshaft reaches a minimum speed. This reduces the torque required to start the heat engine, thus reducing the cost of the start-up installation. By using an electromagnet device, the normal magnetic force at the surface is used and not the tangential one, thus reducing the volume of the device and the amount of materials used.

The invention has the following advantages:

each valve can be closed and opened independently according to an optimal trajectory depending on the operating point of the heat engine;

- does not require a mechanical distribution system;

- at start-up all valves can be controlled in the open position by reducing the torque required to start the heat engine and thus the cost of the starting system;

- in the event of a low load, all valves for certain cylinders that will not be used can be opened for large thermal engines, thus reducing fuel consumption and emissions;

- uses the force of magnetic attraction thus reducing the size of the device and the amount of energy consumed;

- does not require energy to keep the valve in the fully open, fully closed or middle position;

- the permanent magnet is not demagnetized due to the current in the coil because the flow produced by it does not close through the permanent magnet; the inductance of the electrical circuit is relatively constant, so the time constant of the electrical circuit is small and does not vary significantly with position;

- only one static power converter is required for each valve;

- the principle of concentration of the flux created by the permanent magnet can be applied, thus increasing the force density and therefore the weight of the device will be reduced;

- the permanent magnet placed between the two magnetic cores of the stator contributes to the increase of the mechanical robustness of the device, the reduction of vibrations and noise;

the thickness of the magnetic disks of the moving part is independent of the maximum stroke, so the weight of the moving disks and the maximum force developed by the springs are reduced.

The following are two examples of embodiments of the invention in connection with FIG. 1 ... 3, which represent:

- fig. 1, longitudinal section through the electromagnetic drive, with the magnet divided;

ffv-1008-005851 1 -07- 2008 fig.2, cross section through the electromagnetic drive device, with the magnet divided;

fig.3, longitudinal section through the electromagnetic actuating device with the axially undivided magnet;

fig. 4, cross-section through the electromagnetic drive device with the permanent magnet undivided cross-section.

The device for actuating the heat engine valves according to the invention, in a first constructive variant, consists of two fixed magnetic cores, one internal Si and the other external S ₂ between which are placed the permanent magnets MP axially divided - fig. 1 or / and transversely - fig.2, having the coils Bl and B2 on either side of the permanent magnet so that depending on the direction of the current through the coils, the magnetic field is strengthened at one end and weakened at the other end attracting the disk more strongly Di or disc D ₂ , discs integral with the valve by means of the rod T, producing the displacement of the equipment formed by the two discs, rod and valve in one of the extreme positions; when supplying the coils with a signal current opposite to the current that produced the current position, the magnetic field produced by the permanent magnet is weakened by the disk near the core of the internal stator and the field produced by the permanent magnet between the central magnetic core and the remote disk is strengthened. from this, allowing the compressed spring R1 or R2 to detach the mobile equipment from the current position and then move it to the opposite position or to the central equilibrium point.

The device for actuating the heat engine valves according to the invention, in the second constructive variant, consists of two fixed magnetic cores, one internal Si and the other external S ₂ between which is placed a permanent magnet MP not axially divided - fig. 3 and transversely - fig.4, having the coils Bl and B2 on either side of the permanent magnet so that depending on the direction of the current through the coils the magnetic field is strengthened at one end and weakened at the other end attracting more strongly the disk Di or disk D ₂ , discs integral with the valve by means of the rod T, producing the movement of the equipment formed by the two discs, rod and valve in one of the extreme positions; when supplying the coils with a signal current opposite to the current that produced the current position, the magnetic field produced by the permanent magnet weakens through the disk near the core of the internal stator and the field produced by the permanent magnet between the central magnetic core and the disk at a distance from this, allowing the compressed spring R1 or R2 to detach the mobile equipment from the current position and then move it to the opposite position or to the central equilibrium point.

Claims (2)

^ - ‘1 008-005851 1 -07- 2008 demand 1. Electromagnetic device for actuating the valves of heat engines characterized in that, for the purpose of actuating the valves uses a prepolarized electromagnet consisting of two fixed magnetic cores, one internal Si and the other external S ₂ between which are placed the permanent magnets MP divided axially and / or transversely , having the coils Bl and B2 on either side of the permanent magnet so that depending on the direction of the current through the coils the magnetic field is strengthened at one end and weakened at the other end attracting more strongly the disk Di or disk D ₂ , solid disks with valve by means of the T-rod, producing the movement of the equipment consisting of the two discs, the rod and the valve in one of the extreme positions; when supplying the coils with a current of the opposite sign to the current that produced the current position, the magnetic field produced by the permanent magnet weakens through the disk near the core of the internal stator and the field produced by the permanent magnet between the central magnetic core and the disk at a distance from this, allowing the compressed spring R1 or R2 to detach the mobile equipment from the current position and then move it to the opposite position or to the central equilibrium point. 2. Electromagnetic device for actuating the valves of heat engines characterized in that, for the purpose of actuating the valves uses a pre-polarized electromagnet consisting of two fixed magnetic cores, one internal Si and the other external S ₂ between which is placed a permanent magnet MP not divided axially and transversely, having the coils Bl and B2 on either side of the permanent magnet so that depending on the direction of the current through the coils the magnetic field is strengthened at one end and weakened at the other end attracting more strongly the disk Di or disk D ₂ , disks the valve by means of the rod T, producing the displacement of the equipment formed by the two discs, rod and valve in one of the extreme positions; when supplying the coils with a signal current opposite to the current that produced the current position, the magnetic field produced by the permanent magnet is weakened by the disk near the core of the internal stator and the field produced by the permanent magnet between the central magnetic core and the disk at a distance from this, allowing the compressed spring R1 or R2 to detach the mobile equipment from the current position and then move it to the opposite position or to the central equilibrium point.