Internal-combustion engines – Poppet valve operating mechanism – Electrical system
Reexamination Certificate
1999-11-23
2001-05-29
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Electrical system
C123S090490, C251S129100, C251S129150
Reexamination Certificate
active
06237550
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a solenoid-operated valve for opening and closing an intake or exhaust port of an internal combustion engine.
2. Description of the Related Art
There have heretofore been known solenoid-operated valves having a valve body that is operated by solenoids to open and close an intake or exhaust port of an internal combustion engine. Such a solenoid-operated valve has a movable plate connected to the valve body by a transmission valve stem, and first and second solenoids disposed in confronting relation to each other with the movable plate interposed therebetween. The movable plate is attracted by electromagnetic forces that are alternately generated by the first and second solenoids so as to move between the first and second solenoids. When the movable plate is attracted to the first solenoid, the valve body closes the intake or exhaust valve, and when the movable plate is attracted to the second solenoid, the valve body opens the intake or exhaust valve.
If the electric energy alternately supplied to the first and second solenoids is of a constant level, then the electromagnetic force applied to the movable plate by the first solenoid and the electromagnetic force applied to the movable plate by the second solenoid are small when the movable plate is spaced from the first solenoid or the second solenoid, and becomes progressively greater when the movable plate moves closer to the first solenoid or the second solenoid. Therefore, the speed at which the movable plate is displaced increases as the movable plate moves closer to the first solenoid or the second solenoid. When the movable plate is attracted to the first solenoid, since the valve body is displaced at an increased speed, the valve body abruptly closes the intake or exhaust port, tending to produce noise and vibrations when the valve body hits the intake or exhaust port. The movable plate also tends to produce noise and vibrations as it is abruptly attracted to the first solenoid and the second solenoid.
To avoid the above drawbacks, it is customary to supply an increased amount of the electric energy, e.g., a current, to the first and second solenoids when the movable plate is far from the first solenoid or the second solenoid, and supply a reduced amount of the electric energy, e.g., a current, to the first and second solenoids when the movable plate is positioned closely to the first solenoid or the second solenoid. In this manner, when the movable plate is far from the first solenoid or the second solenoid, the speed at which the movable plate is displaced is high, and after the movable plate is positioned closely to the first solenoid or the second solenoid, the speed at which the movable plate is displaced is lowered.
However, controlling only the electric energy supplied to the first and second solenoids is not enough to quickly reduce the speed at which the movable plate is displaced after the movable plate is positioned closely to the first solenoid or the second solenoid.
According to one known solution, a slider is provided to slidingly contact the movable plate or the transmission valve stem when the movable plate is positioned closely to the first solenoid or the second solenoid, thereby exerting an increased sliding resistance to the movable plate or the transmission valve stem. In this fashion, when the movable plate is attracted to the first solenoid or the second solenoid, the movable plate is quickly decelerated to reduce the noise or vibrations produced when the movable plate is attracted to the solenoid. Since the slider is disposed for sliding contact with the movable plate or the transmission valve stem when the movable plate is positioned closely to the first solenoid or the second solenoid, when the movable plate is positioned out of sliding contact with the slider, i.e., positioned away from the solenoid, the movement of the movable plate under the magnetic attractive forces from the solenoid is not impaired by the slider. Consequently, the movable plate can move at sufficient speeds between the first and second solenoids, and can quickly be decelerated after it is positioned closely to the solenoid until attracted thereto.
However, increasing the sliding resistance to the movable plate or the transmission valve stem thereby to reduce the speed at which the movable plate is displaced results in undue wear on the movable plate or the transmission valve stem. After use of the solenoid-operated valve over a long period of time, consequently, the movable plate may not be sufficiently be decelerated.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a solenoid-operated valve for use in an internal combustion engine, which has a movable plate and a transmission valve stem that are highly durable without being subject to undue wear, and that are capable of reliably reducing noise and vibrations.
To achieve the above object, there is provided in accordance with the present invention a solenoid-operated valve for use in an internal combustion engine, comprising a valve body movable into and out of abutment of an intake/exhaust port in the internal combustion engine to close and open an intake/exhaust passage in communication therewith, a movable plate connected to the valve body by a transmission valve stem, a first solenoid for magnetically attracting the movable plate to cause the valve body to close the intake/exhaust port, a second solenoid disposed in confronting relation to the first solenoid with the movable plate interposed therebetween, for magnetically attracting the movable plate to cause the valve body to open the intake/exhaust port, a piston movable in unison with the transmission valve stem until the valve body closes the intake/exhaust port when the first solenoid magnetically attracts the movable plate to position the valve body closely to the intake/exhaust port, and a cylinder for gradually discharging a fluid filled therein in response to movement of the piston, for thereby causing the transmission valve stem to reduce a speed at which the valve body closes the intake/exhaust port.
With the above arrangement, the first solenoid magnetically attracts the movable plate to cause the valve body to close the intake/exhaust port through the transmission valve stem connected to the movable plate. At this time, the piston moves in the cylinder in unison with the transmission valve stem after the valve body is positioned closely to the intake/exhaust port until it closes the intake/exhaust port. Since the cylinder gradually discharges the fluid filled therein upon movement of the piston, the resistance to the discharging of the fluid from the cylinder suppresses quick movement of the piston. With quick movement of the piston being suppressed, the speed at which the transmission valve stem moves is reduced, sufficiently decelerating the valve body when it closes the intake/exhaust port. Accordingly, the valve body is prevented from abruptly closing the intake/exhaust port, for thereby reliably reducing noise and vibrations produced when the valve body closes the intake/exhaust port.
When the cylinder suppresses quick movement of the piston, the transmission valve stem reduces the speed at which the movable plate is displaced. Therefore, noise and vibrations produced when the movable plate is attracted to the first solenoid are reliably lowered.
Furthermore, inasmuch as the fluid is gradually discharged from the cylinder upon movement of the piston, lowering the speed at which the valve body is displaced and the speed at which the movable plate is displaced, the movable plate and the transmission valve stem are subject to much less wear and are much more durable than the conventional solenoid-operated valves in which the speeds of the movable plate and the transmission valve stem are reduced by increasing the resistance to their sliding movement.
The piston moves in unison with the transmission valve stem when the movable plate is positioned closely to the first solenoid. The
Hatano Harumi
Ikoma Kouichi
Onohara Yoshinori
Sugimoto Chihaya
Arent Fox Kintner Plotkin & Kahn
Honda Giken Kogyo Kabushiki Kaisha
Lo Weilun
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