Internal-combustion engines – Poppet valve operating mechanism – Electrical system
Reexamination Certificate
2000-05-05
2001-10-23
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Electrical system
C123S090600, C123S090650, C251S129010, C251S129160
Reexamination Certificate
active
06305336
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an electromagnetic driving device that operates an engine valve for an internal combustion engine of an automobile. This type of the electromagnetic driving devices have been proposed, for example the prior art disclosed in Japan unexamined publication (Koukai) No.8-21220, in which an intake valve slidably disposed on a cylinder head is operated by a magnetic force. Referring now to
FIG. 12
, there is an electromagnetic driving device that includes a driving mechanism
103
that controls the opening and closing status of an intake valve
102
. The intake valve
102
includes a valve portion
1002
a
that opens and closes an opening of an intake port
104
and a valve stem
102
b
that is integrated with an upper end of the valve portion
102
a.
The electromagnetic driving mechanism
103
comprises an armature
106
that is encased in a casing
105
fixed on the cylinder head
100
, is shaped like a plate, and is couple with the upper end of the valve stem
102
b
, and a pair of electromagnets. In particular, a closing-electromagnetic
107
and an opening-electromagnetic
108
are housed in the respective upper and lower portion of the casing
105
and are placed opposite side of the armature
106
for attracting the armature
106
so as to open and close the intake port
104
. An armature spring
109
is installed between an upper wall of the casing
105
and an upper surface of the armature
106
and urges the valve
102
to close the opening of the intake port
104
. Similarly, a valve spring
110
is interposed between a concave portion
101
of the cylinder head
100
and a lower surface of the armature
106
, and urges the valve
102
to close the opening of the intake port
104
. Further, each coil of the closing and opening-electromagnets
107
,
108
is energized through an amplifier
111
according to a control signal produced by an electronic control unit
112
. The electronic control unit
112
produces the control signal that controls a power-supply to the closing and opening-electromagnets
107
,
108
based on any of plural detected signals, such as an engine revolution detected by an engine revolution sensor
113
and a temperature of coolant detected by the thermometer
114
. Also, a power source designated
115
supplies a power to each coil of the closing and opening-electromagnets
107
,
108
. Thereby, the spring forces of the valve and armature spring
109
,
110
and the attracting forces of the electromagnetic
107
,
108
are retained in respective springs
109
,
110
as a potential energy. With this, the valve
102
is alternatively attracted and released by one of the closing and opening electromagnets
107
,
108
to open or close the opening of the intake port
104
using that potential energy.
In the prior art, however, the attracting force of the closing and opening-electromagnets
107
,
108
is larger than the spring forces of the armature and valve spring
109
,
110
urging the armature
106
against respective attracting forces, so that the end of the valve portion
102
a
might collide with a valve seat
104
a
of the cylinder head when the valve
102
closes the opening of the intake port, and the armature
106
might collide with the opening-electromagnetic
108
when the valve
102
opens the opening of the intake port. Referring to
FIG. 13A
,
13
B, there is shown the principle of the attracting force for the closing and opening-electromagnets
107
,
108
. First,
FIG. 13B
shows the characteristics of the spring force between the attracting force of the electromagnets
107
,
108
and the spring forces of the armature and valve spring
109
,
110
when the valve
102
closes the opening of the intake port, the armature
106
is attracted to the closing-electromagnetic
107
. Thereby, the valve spring
110
is extended and the armature spring
109
is compressed, so that a spring force of the armature spring
109
is accumulated therein. Next when the valve
102
opens the opening of the intake port, the closing electromagnet is de-energized, and alternatively the opening-electromagnet
108
is energized, thereby the armature
106
is attracted to the opening-electromagnetic
108
. Therefore, the armature spring
109
is extended and the valve spring
110
is compressed, so that a spring force of the valve spring
110
is accumulated therein. Namely, respective accumulated forces of the armature and valve spring
109
,
110
affects the armature
106
to reduce the speed of the armature
106
approaching the electromagnets
107
,
108
. On the other hand, because the attracting force of the electromagnet is increased indirectly by the second power of a distance between the core of the electromagnets
107
a
,
108
a
, the attracting forces of the electromagnets are suddenly increased when the armature
106
is close to the electromagnets. Therefore, since the accumulated spring forces are not large enough to reduce the increased attracting force of the electromagnetic, the armature
106
is suddenly urged toward the one of the electromagnets
107
,
108
when the armature
106
approaches close to one of the electromagnets
107
,
108
. As seen in
FIG. 13A
, due to a sudden increased attracting force of the electromagnets
107
,
108
, the valve
102
collides with the valve seat
104
a
, when the valve closes the opening of the intake port, and the armature
106
collides with the opening-electromagnet
108
, when the valve
102
opens it. Thereby, such a collision causes not only noise but also might cause wear and a fracture of the armature
106
and the valve seat
104
a.
Moreover, the prior art requires an arrangement that balances the force between the attracting force of the closing-electromagnet
107
and the armature spring
109
, in order to make the valve portion
102
a
urged toward the valve seat
104
a
with an appropriate force. However, since a gap between the armature
106
and the core of the electromagnet
107
a
is varied because of wear of the armature
106
, the valve springs
109
,
110
and the valve seat
104
a
and a heat expansion of the valve stem
102
b,
thereby the attracting force is also varied from the required value. Thus, the gap will occur between the valve portion
102
a
and the valve seat
104
a,
so that the valve portion
102
a
might not be capable of closing the opening of the intake port
104
tightly and might be covered with foreign matter. If so, the valve also might be melted since the foreign matter prevents dissipating heat therefrom.
Also, method of assembly of the prior art structure of
FIG. 12
will be described. At first the valve
102
is inserted in the cylinder head
101
from the opening of the intake port
104
a.
Then, the opening-electromagnet
108
is disposed on the cylinder head
101
. Finally, the armature
106
is coupled with the end of the valve stem
102
b
with installing the armature and valve springs
109
,
110
. Therefore, the prior art requires that assembly has to be performed using on the cylinder head
101
, and an accurate arrangement of upper and lower position of the armature
106
with respect to the electromagnets
107
,
108
. Accordingly, the prior art increases the cost of the manufacturing and manufacturability.
SUMMARY OF THE INVENTION
It is, therefore, an object to the present invention is to provide an improved electromagnetic driving device for a engine valve which is capable of preventing a collision between a valve and a valve seat of a cylinder head, and a collision between an armature and an electromagnet. Another object of the invention is to provide an improved electromagnetic driving device for an engine valve that can be assemble easily and be installed to the cylinder head.
In order to achieve these and other objects, there is provided an electromagnetic driving device for an engine that comprises an electromagnetic driving mechanism having first and second electromagnets that are placed on opposite sides of an armature, a controller that controls magnetic forces of the electromagnets in
Hara Seinosuke
Hibi Tsutomu
Todoroki Katsuhisa
Yamada Yoshihiko
Lo Weilun
Sughrue Mion Zinn Macpeak & Seas, PLLC
Unisia Jecs Corporation
LandOfFree
Electromagnetic driving device of engine valve for internal... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electromagnetic driving device of engine valve for internal..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electromagnetic driving device of engine valve for internal... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2601526