Internal-combustion engines – Poppet valve operating mechanism – Electrical system
Reexamination Certificate
2000-06-07
2001-08-21
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Electrical system
C251S129010
Reexamination Certificate
active
06276318
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a solenoid valve actuating apparatus, and more particularly, to a solenoid valve actuating apparatus suitable for actuating a plurality of valves operating in synchronism with each other such as, for example, a plurality of intake valves or exhaust valves provided for each cylinder of an internal combustion engine, or the like.
BACKGROUND ART
Conventionally, for example as disclosed in Japanese Laid-Open Patent Application 8-284626, a solenoid valve for use as an intake or exhaust valve of an internal combustion engine is known. This solenoid valve is provided with an armature moving with an engine valve as a unity, a pair of solenoid coils disposed above and below the armature, and springs pushing the engine valve toward a neutral position.
When neither of the solenoid coils is supplied with an exciting current, the engine valve and the armature are held in the neutral position. Further, when an upper solenoid coil is supplied with the exciting current, the engine valve and the armature are attracted to the upper solenoid coil, while the engine valve and the armature are attracted to a lower solenoid coil when the lower solenoid coil is supplied with the exciting current. Therefore, according to the above described conventional solenoid valve, the engine valve can be operated so as to be opened and closed by alternately supplying the solenoid coils with proper exciting currents. In this case, ends of movement on closing and opening sides of the engine valve are controlled by the adhesion of the armature to the solenoid coils. Therefore, if electromagnetic forces generated by the solenoid coils can be made to promptly vanish in positions near the ends of movement of the engine valve, an excellent operational responsiveness of the solenoid valve can be realized, and the control of an impact sound and the improvement in durability are made possible because impact forces exerted between the armature and the solenoid coils are reduced.
For this purpose, the exciting currents supplied to the solenoid coils are controlled by a bridged-H-type circuit in the above described conventional solenoid valve. This bridged-H-type circuit includes a total of four switching means disposed respectively between terminals of the solenoid coil, and cathode and anode sides of a power supply. According to the bridged-H circuit, the solenoid coil can be energized in a predetermined direction by setting one pair of the switching means which are disposed diagonally across the solenoid coil to an ON state and the other pair to an OFF state. Further, the solenoid coil can be energized in the reverse direction by reversing the above described ON and OFF states. Therefore, the electromagnetic force generated by the solenoid coil can be made to promptly vanish by energizing the solenoid coil in the reverse direction to the exciting current by switching the ON and OFF states of the switching means of the bridged-H-type circuit when the engine valve approaches the end of movement.
However, as described above, the above described conventional solenoid valve requires four switching means for each of the solenoid coils. That is, eight switching means will be required for one solenoid valve as one solenoid valve is provided with two solenoid coils. Therefore, when the above described conventional solenoid valve is applied to an engine of a four-cylinder-four-valve type, for example, one hundred and twenty-eight switching means will be required, thus causing the cost of an actuating apparatus for actuating the solenoid valves to rise.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to reduce a number of switching means required to control an exciting current to a solenoid coil to actuate an engine valve.
The above object is achieved by a solenoid valve actuating apparatus for actuating a plurality of engine valves, for each of which provided are a first electromagnet to actuate the engine valve in a first predetermined direction and a second electromagnet to actuate the engine valve in a second predetermined direction, by means of the first and the second electromagnets so that a plurality of the engine valves will be opened and closed, the solenoid valve actuating apparatus wherein:
two of the engine valves form one engine valve group and an actuating circuit is provided for each of the engine valve groups;
the actuating circuit includes three series circuits each having three switching means connected in series between a first line terminal on a high voltage side and a second line terminal on a low voltage side; and
four of the electromagnets corresponding to each of the engine valve groups connect connecting-in-series portions between the switching means between different series circuits.
In the present invention, each of the engine valves is actuated by the first and the second electromagnets in the first and the second predetermined directions, respectively. Two of the engine valves form one engine valve group and the actuating circuit is provided for each of the engine valve groups. The actuating circuit includes the three series circuits each having the three switching means connected in series. Therefore, the exciting currents to the four electromagnets corresponding to the two engine valves can be controlled by nine of the switching means. The four electromagnets are connected between the different series circuits. Therefore, each of the electromagnets can be supplied with the exciting currents in both directions by the combinations of ON and OFF states of the switching means of each of the series circuits, and electromagnetic forces exerted on the engine valve can be made to promptly vanish by enabling currents flowing through the electromagnets to flow into the first line terminal.
In this case, the actuating circuit may include a first through third series circuits having a first through third switching means connected in series in order from the first line terminal side between the first line terminal and the second line terminal, and the four electromagnets may be connected between a connecting portion of the first and the second switching means of the first series circuit and a connecting portion of the first and the second switching means of the second series circuit, between a connecting portion of the second and the third switching means of the first series circuit and a connecting portion of the second and the third switching means of the second series circuit, between the connecting portion of the first and the second switching means of the second series circuit and a connecting portion of the first and the second switching means of the third series circuit, and between the connecting portion of the second and the third switching means of the second series circuit and a connecting portion of the second and the third switching means of the third series circuit, respectively.
In the present invention, the actuating circuit includes the first through third series circuits wherein the first through third switching means are connected in series between the first line terminal and the second line terminal. The four electromagnets are connected between the series circuits. For example, a state wherein the exciting current is supplied from the second series circuit side in a direction toward the first series circuit side (hereinafter referred to as a first direction) is formed of the electromagnet connected between the connecting portion of the first and the second switching means of the first series circuit and the connecting portion of the first and the second switching means of the second series circuit by setting to the ON state the first switching means of the second series circuit, and the second and the third switching means of the first series circuit. Further, a state wherein the exciting current flowing in the first direction flows into the first line terminal or the exciting current is supplied in the reverse direction to the first direction is formed by setting to the ON state the first switching means of the first series
Fuwa Toshio
Kadowaki Yoshinori
Yanai Akihiro
Kenyon & Kenyon
Lo Weilun
Toyota Jidosha & Kabushiki Kaisha
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