Internal-combustion engines – Poppet valve operating mechanism – Electrical system
Reexamination Certificate
2001-11-15
2004-04-27
Denion, Thomas (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Electrical system
C251S129100, C123S090150
Reexamination Certificate
active
06725816
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for and a method of controlling a solenoid-operated valve device for use as an intake or exhaust valve device in an internal combustion engine.
2. Description of the Related Art
There have heretofore been known solenoid-operated valve devices for use as intake or exhaust valves device in internal combustion engines. The basic structure of a conventional solenoid-operated valve device of the type described is shown in
FIG. 1
of the accompanying drawings.
FIG. 1
illustrates a solenoid-operated valve device for use as an intake or exhaust valve device in an internal combustion engine. As shown in
FIG. 1
, the solenoid-operated valve device has a valve head
3
mounted on one end of a shank
3
a
and a plate-like armature
4
made of a magnetic material such as iron or the like which is mounted on the other end of the shank
3
a
. The valve head
3
serves to selectively open and close a port
2
as an intake port or an exhaust port (hereinafter referred to as “intake/exhaust port
2
”) of a combustion chamber
1
of each of the cylinders of an internal combustion engine. The valve head
3
is vertically reciprocally movable, together with the armature
4
along the axis of the shank
3
a
, between a closed position in which it closes the intake/exhaust port
2
and an open position in which it fully opens the intake/exhaust port
2
.
Another solenoid-operated valve device also has a drive rod (not shown) held in concentric contact with the upper end of a valve stem and movable in unison with the valve stem, with an armature being mounted on the drive rod. In this solenoid-operated valve device, the valve stem and the drive rod jointly correspond to the shank
3
a
shown in FIG.
1
.
Electromagnets
5
,
6
having respective solenoids
5
a
,
6
a
housed therein are disposed above and below the armature
4
in confronting relation to each other. When the solenoid
5
a
is energized, the electromagnet
5
serves as a valve closing electromagnet which moves the armature
4
upwardly together with the valve head
3
and attracts the armature
4
under electromagnetic forces, thereby moving the valve head
3
into the closed position. When the solenoid
6
a
is energized, the electromagnet
6
serves as a valve opening electromagnet which moves the armature
4
downwardly together with the valve head
3
and attracts the armature
4
under electromagnetic forces, thereby moving the valve head
3
into the open position.
A spring
7
for urging the armature
4
and the valve head
3
in the direction to open the valve head
3
, i.e., in the downward direction, is disposed above the armature
4
, and a spring
8
for urging the armature
4
and the valve head
3
in the direction to close the valve head
3
, i.e., in the upward direction, is disposed beneath the armature
4
. When the electromagnets
5
,
6
are de-energized, the valve head
3
is kept in a neutral position shown as the solid-line position in
FIG. 1
between the closed position and the open position under the biasing forces of the springs
7
,
8
which are held in equilibrium. Thus, the springs
7
,
8
jointly function as a biasing means for urging the valve head
3
in the neutral position.
With the above solenoid-operated valve device, it is necessary to determine a position to which the valve head
3
is to move before the solenoid-operated valve device starts operating with the internal combustion engine. To meet such a requirement, before the internal combustion engine starts operating, the valve head
3
is moved to an initial position, which is either the open position or the closed position, from the neutral position in which the valve head
3
is kept when the electromagnets
5
,
6
are de-energized. Such a moving process is hereinafter referred to as “initial actuating process”).
The solenoid-operated valve device is controlled in the initial actuating process as disclosed in Japanese laid-open patent publication No. 59-213913 and Japanese laid-open patent publication No. 10-288014, for example.
According to the disclosed control processes, the electromagnets
5
,
6
are alternately periodically energized to generate alternate electromagnetic forces which vibrate the valve head
3
and the armature
4
. The electromagnets
5
,
6
are energized for a period of time which is half the period of the natural frequency (resonant frequency) of the spring-mass system comprising the valve head
3
, the shank
3
a
, the armature
4
, and the springs
7
,
8
, or which becomes closer stepwise from a period of time somewhat longer than half the period to half the period, thus progressively increasing the amplitude of the vibrations of the valve head
3
, etc. based on the resonance of the spring-mass system. When the amplitude of the vibrations of the valve head
3
, etc. becomes sufficiently large, the alternate energization of the electromagnets
5
,
6
is finished, and only the electromagnet
5
or
6
corresponding to the initial position (the open or closed position) of the valve head
3
is continuously energized. The electromagnetic forces generated by the electromagnet
5
or
6
corresponding to the initial position attract the armature
4
, seating the valve head
3
in the initial position.
According to Japanese laid-open patent publication No. 59-213913, the arrival of the valve head
3
at the open or closed position due to the alternate energization of the electromagnets
5
,
6
is recognized based on a reduction in the current passing through the electromagnet
5
or
6
, and the alternate energization of the electromagnets
5
,
6
is finished when the arrival of the valve head
3
at the open or closed position is recognized. According to Japanese laid-open patent publication No. 10-288014, when the electromagnets
5
,
6
are alternately energized a predetermined number of times, the amplitude of the vibrations of the valve head
3
, etc. is regarded as being sufficiently large, and the alternate energization of the electromagnets
5
,
6
is finished.
According to the disclosed arrangements, since the resonance of the spring-mass system is utilized, the initial actuating process may be performed with a smaller current supplied to the electromagnets
5
,
6
than if only the electromagnet
5
or
6
corresponding to the initial position were continuously energized to move the valve head
3
to the initial position under electromagnetic forces generated by the electromagnet
5
or
6
.
However, the disclosed processes have suffered the following drawbacks:
When the electromagnets
5
,
6
are alternately energized in the initial actuating process, one of the electromagnets is de-energized and at the same time the other electromagnet is energized, and hence either one of the electromagnets is energized at all times (see
FIGS. 2 and 3
of Japanese laid-open patent publication No. 59-213913 and
FIG. 2
of Japanese laid-open patent publication No. 10-288014).
When the valve opening electromagnet
6
, for example, is de-energized and the valve closing electromagnet
5
starts being energized, the armature
4
is spaced relatively widely from the valve closing electromagnet
5
, and the electromagnetic forces of the valve closing electromagnet
5
do not well act on the armature
4
. In this state, the armature
4
can move toward the valve closing electromagnet
5
under the bias of the springs
7
,
8
. This also holds when valve closing electromagnet
5
is de-energized and the valve opening electromagnet
6
starts being energized.
Therefore, when the electromagnets
5
,
6
are alternately energized, supplied currents are often wasted in certain intervals as they do not contribute to the vibration of the valve head
3
, etc., resulting in an excessive consumption of electric energy in the initial actuating process.
According to Japanese laid-open patent publication No. 10-288014, the alternate energization of the electromagnets
5
,
6
is finished when they have been alternately energized a c
Abe Kenji
Nakamura Minoru
Yamaki Toshihiro
Corrigan Jaime
Denion Thomas
Lahive & Cockfield LLP
Laurentano Anthony A.
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