JP2740965B2 - Electromagnetic exhaust valve drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electromagnetic force exhaust that opens and closes an exhaust valve by an electromagnet that is excited by a charge stored in a capacitor to resist a pressure in a combustion chamber when the valve is opened. The present invention relates to a valve driving device.

(Prior Art) The intake and exhaust valves of a conventional engine are driven to open and close by a camshaft. Since the camshaft is interlocked with the crankshaft, the opening / closing timing of the intake / exhaust valve with respect to the crank angle cannot be changed according to the change in the engine speed. Therefore, since the opening / closing timing of the intake / exhaust valve is adjusted so that the efficiency becomes high at a specific rotational speed, there is a problem that the efficiency is reduced when the engine is operated at a rotational speed other than the specific rotational speed.

Therefore, by opening and closing the intake and exhaust valves with electromagnetic force by an electromagnet, the opening and closing timings of the intake and exhaust valves can be changed according to changes in the engine speed, and high efficiency operation can be performed at each engine speed. An intake and exhaust valve driving device capable of realizing an engine is disclosed in Japanese Patent Application Laid-Open No. 58-1838.
No. 05 and JP-A-61-76713.

(Problems to be Solved by the Invention) In such a conventional valve driving apparatus that opens and closes an intake and exhaust valve by an electromagnet, the drive force required for opening and closing the intake and exhaust valves is relatively small. When the valve is opened, the exhaust valve must be driven against the pressure in the combustion chamber, requiring a large driving force. Therefore, there is a problem that the electromagnet for driving the exhaust valve becomes large or cannot be opened due to insufficient driving force.

The present invention has been made in view of the above problems, and has an electromagnetic exhaust valve capable of generating a driving force against the pressure in a combustion chamber when the valve is opened, and reliably driving the exhaust valve to discharge the exhaust. It is intended to provide a driving device.

(Means for Solving the Problems) According to the present invention, a disk-shaped movable magnetic pole made of a magnetic material, which is connected to an intake / exhaust valve of an engine and is stacked in multiple stages in a reciprocating reciprocating direction, A fixed magnetic pole facing one end of the movable magnetic pole in a reciprocating direction; and a first magnetic pole excited by electric charge from a capacitor to generate a magnetic flux in the first movable magnetic pole.
And a second coil for generating a magnetic flux excited by the electric charge from the capacitor on the fixed magnetic pole, and a second coil facing the side surfaces of the plurality of movable magnetic poles and arranged in parallel in the reciprocating direction. There can be provided an electromagnetic force exhaust valve driving device, characterized by comprising an energization control means for controlling an energization state of an electrode formed with a magnetic path and an electromagnet composed of a coil to drive the valve.

(Function) In the electromagnetic exhaust valve driving device of the present invention, the electromagnet for driving the exhaust valve in the opening direction is excited by the electric charge charged in the capacitor, so that a large current can be supplied to the electromagnet. A driving force against the pressure in the combustion chamber when the valve is opened can be generated.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall configuration diagram of an exhaust valve driving device according to the present invention.

Reference numeral 1 denotes an exhaust valve formed of a lightweight and high-strength material such as ceramics. The shaft of the exhaust valve 1 passes through a valve guide 11 provided on a cylinder head 9 of the engine and is slidable in the axial direction. It is bearing. Reference numeral 91 denotes an exhaust passage, and reference numeral 92 denotes a valve seat on which the exhaust valve 1 is seated when the valve is closed. A magnetic passage 2 made of a magnetic material is fitted to a shaft end of the exhaust valve 1. A first movable magnetic pole 21 and a second movable magnetic pole 22 are provided around the shaft end of the magnetic path body 2. The first movable magnetic pole 21 is located at a position surrounding the first movable magnetic pole 21 when the exhaust valve 1 is in the closed state.
A coil 23 is provided. Also, a spring for preventing the exhaust valve 1 from falling when the engine is stopped.
24 is provided between the valve guide 11 and the magnetic path body 2.

An upper fixed magnetic pole 31 facing the upper end surface of the first movable magnetic pole 21 and a second coil 32 wound around the upper fixed magnetic pole 31 are disposed above the magnetic path body 2. The upper fixed magnetic pole 31
The yoke member 3 extends along the side surface of the magnetic path body 2 to a lower end portion in contact with the side surface of the magnetic path body 2, and forms a lower magnetic pole 33 facing the lower end portion of the side surface. The lower magnetic pole
33 is provided with a lower coil 34 surrounding the magnetic path body 2. Between the upper fixed magnetic pole 31 and the lower magnetic pole 33, the intermediate magnetic poles 41, 42, and 43 facing the first movable magnetic pole 21 and the second movable magnetic pole 22 project during the movement of the magnetic path body 2,
Coils 44, 45 and 46 are wound around the respective intermediate magnetic poles 41, 42 and 43.

The lower coil 34 is connected to the power supply device 5 and is always energized in a direction that generates an upward magnetic flux in the magnetic path 2. The coils 44, 45, and 46 are also connected to the power supply device 5, and are supplied with three-layer alternating current in a direction in which an upward traveling magnetic field is formed.

One terminal of the second coil 32 is connected to the power supply 5 via a variable resistor 51 and a capacitor 52, and the other terminal is connected to the power supply 5 via a normally closed switch 53. The terminal on the second coil 32 side of the normally closed switch 53 is connected via a normally open switch 54. The first coil
23 is connected to the power supply device 5 via a variable resistor 55, a capacitor 56, a normally closed switch 57, and a normally open switch 58 through a circuit configuration similar to that of the second coil 32.

Normally closed switch 53, normally open switch 54, normally closed switch
The normally open switch 57 is connected to an input / output interface 64 of the control unit 6, and is opened and closed by a signal from the input / output interface 64. The control unit 6 includes, in addition to the input / output interface 64, a ROM 62 for storing programs and various relation maps in advance,
CPU61 which performs an operation under the program stored in 62,
It comprises a RAM 63 for temporarily storing the calculation results and data, a control memory for controlling the flow of signals in the control unit, and the like. The input / output interface 64 is connected to the rotation sensor 7 for detecting the number of revolutions of the engine and the crank angle θ in addition to the above switches.

Next, the operation of the exhaust valve driving device according to the present invention will be described with reference to FIG.

FIG. 2 is a valve characteristic diagram showing the relationship between the displacement of the exhaust valve and the valve driving force F with respect to the crank angle θ.

In the figure, the upper curve shows the amount of movement of the exhaust valve 1 with respect to the crank angle θ, and the lower curve shows the valve driving force F with respect to the crank angle θ. In the valve driving force F, the direction in which the exhaust valve 1 is driven in the opening direction is indicated by +, and the direction in which the exhaust valve 1 is driven in the closing direction is indicated by-.

By the way, at the end of the expansion stroke, the exhaust valve 1 must be opened to exhaust the exhaust inside the combustion chamber. If the pressure inside the combustion chamber at the end of the expansion stroke is 5 kg / cm ² , the area of the exhaust valve 1 on the combustion chamber side is assumed. Is 8 cm ² , the electromagnetic force required for the exhaust valve 1 to open against the internal pressure is 40 kgf
(392N). Considering the driving force required for accelerating the exhaust valve 1 at the time of opening, a driving force of about 80 kgf (784 N) must be generated.

The lower coil 34 is always energized from the power supply 5 in a direction to generate an upward magnetic flux in the figure with respect to the magnetic path body 2, and the magnetic flux flows from the upper end surface of the magnetic path body 2 through the upper fixed magnetic pole 31 A closed circuit is formed again from the magnetic pole 33 to the side surface of the magnetic path member 2, and N appears on the upper end surface of the magnetic path member 2.
The exhaust valve 1 is maintained in a closed state by an attractive force acting between the pole and the S pole appearing on the upper fixed magnetic pole 31.

When the crank angle θ detected by the rotation sensor 7 reaches a preset opening timing of the exhaust valve 1, the normally-closed switch 53 and the normally-open switch
An opening / closing signal is output to a normally closed switch 57 and a normally open switch 58, and the capacitor 52 that is in a charged state by a circuit constituted by the variable resistor 51, the capacitor 52, the second coil 32, and the normally closed switch 53 is supplied to the power supply device. 5 and the second
Since a closed circuit is formed by the coil 32 and the normally open switch 54, the electric charge charged in the capacitor 52 is
Supplied to Since the internal resistance of the capacitor 52 is very small, a large current flows through the second coil 32, and a high-density magnetic flux in the downward direction in the figure is generated in the upper fixed magnetic pole 31.

Similarly, a large current is supplied from the capacitor 56 to the first coil 23 in the direction in which an upward magnetic flux is generated in the magnetic path 2. An upward magnetic flux has already been generated in the magnetic path 2 by the lower coil 34, and a magnetic flux having a high density is generated in the magnetic path 2.

As described above, since the directions of the magnetic flux generated in the upper fixed magnetic pole 31 and the magnetic path body 2 are opposite directions, a strong repulsive force acts between the upper end surface of the magnetic path body 2 and the upper fixed magnetic pole 31,
The magnetic passage body 2 and the exhaust valve 1 move rapidly downward, that is, in the opening direction.

By the way, a pulsed current is supplied to the coils 44, 45, and 46 in accordance with a command from the control unit 6, so that the magnetic field formed by the magnetic flux from the magnetic poles 41, 42, and 43 becomes an upward traveling magnetic field. ing. Therefore, the first movable magnetic pole 21 and the second movable magnetic pole 22 moving in the traveling magnetic field are magnetized by the lower coil 34, and the coils 44 and 45 are controlled by the control unit 6. That is, if the first movable magnetic pole 21 and the second movable magnetic pole 22 are the N pole, the magnetic pole 41 becomes the S pole immediately after the valve is opened to promote the valve opening operation, and then the magnetic pole 42 becomes the S pole. In the opening direction. Then, after the opening, the operation opposite to the above opening operation is performed, and after the maximum lift point has elapsed, the exhaust valve 1 is moved upward, that is, in the closing direction.

Next, immediately before the exhaust valve 1 is seated, the open / close signal from the input / output interface 64 to the normally closed switch 53, the normally open switch 54, the normally closed switch 57, and the normally open switch 58 is stopped. Then, since the capacitor 52 and the capacitor 56 are charged via the second coil 32 and the first coil 23, a strong current is again applied between the upper end surface of the magnetic path body 2 and the upper fixed magnetic pole 31 by the charging current. The repulsive force acts, the speed in the closing direction of the exhaust valve 1 is reduced, and the impact when the exhaust valve 1 is seated is reduced. When the charging of the condenser 52 and the condenser 56 is completed, the repulsive force also disappears, and the magnetic flux generated by the lower coil 34 keeps the exhaust valve 1 closed until the next opening timing.

Since the above-described excitation circuit for the first coil 23 and the second coil 32 includes a capacitor and a coil, the current flowing through the circuit oscillates at a predetermined cycle. Therefore, in the above embodiment, the time constant of the first coil 23 and the capacitor 56
Even if the current flowing through the circuit is reversed by vibration by making the time constants of the second coil 32 and the capacitor 52 the same, the electromagnetic force acting between the magnetic path body 2 and the upper fixed magnetic pole 31 is constantly repelled. Help.

Further, the excitation circuit of the first coil 23 and the second coil 32 may have the configuration shown in FIG.

FIG. 3 is a diagram showing another excitation circuit of the first coil 23 and the second coil 32.

As shown in the drawing, the first coil 23 and the second coil 32 connected in series are excited by the one excitation circuit, and the currents flowing through the first coil 23 and the second coil 32 are the same. Therefore, the repulsion does not decrease even when the time constant changes.

In addition, the use of a plurality of capacitors can improve the instantaneous excitation.

 FIG. 4 is a diagram showing another circuit of the capacitor.

At the time of charging, the charging current is increased by the parallel circuit of the capacitor 52 and the capacitor 81, and the amount of current flowing through the first coil 23 and the second coil 32 is increased. Then, at the time of discharging, the charged capacitor 52 and the
And double the voltage by connecting in series with the changeover switch 83,
The amount of current flowing through the first coil 23 and the second coil 32 is increased.

Although the embodiments have been described in detail, various different embodiments can be easily configured without departing from the spirit of the present invention, and therefore, the present invention is not limited to the specific embodiments described in the claims. It is not restricted to.

(Effect of the Invention) As described above, according to the present invention, the electromagnet for driving the exhaust valve in the opening direction is excited by the electric charge charged in the capacitor, so that a large current can be supplied to the electromagnet. Therefore, it is possible to provide an electromagnetically driven exhaust valve driving device capable of generating a driving force against the pressure in the combustion chamber when the exhaust valve is opened.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, FIG. 2 is a valve characteristic diagram showing a relationship between a movement amount of an exhaust valve and a valve driving force F with respect to a crank angle θ, and FIG. FIG. 4 is a diagram showing another excitation circuit of the first coil and the second coil,
The figure shows another circuit of the capacitor. DESCRIPTION OF SYMBOLS 1 ... Exhaust valve, 2 ... Magnetic path body, 5 ... Power supply device, 6 ... Control unit, 7 ... Rotation sensor,
23: First coil, 32: Second coil, 52, 56: Capacitor.

Claims (1)

(57) [Claims] A movable magnetic pole made of a magnetic material, which is connected to an intake / exhaust valve of an engine and is reciprocally movable in a plurality of stages in a reciprocating motion direction, and faces one end of the first movable magnetic pole in a reciprocating direction. A first coil that is excited by the electric charge from the capacitor to generate a magnetic flux in the first movable magnetic pole, and a second coil that generates the magnetic flux excited by the electric charge from the capacitor to the fixed magnetic pole; Energization control for controlling the energization state of an electromagnet composed of an electrode and a coil, which are arranged side by side in the reciprocating direction opposite to the side surfaces of the plurality of movable magnetic poles and form a magnetic path of the fixed magnetic pole and the movable magnetic pole, and drive the valve; Means for driving an electromagnetically driven exhaust valve.