U.S. patent application number 09/901023 was filed with the patent office on 2001-11-08 for valve driving apparatus provided in an internal combustion engine.
This patent application is currently assigned to Toyota Jidosha Kabushiki Kaisha. Invention is credited to Asano, Masahiko, Hattori, Hiroyuki, Iida, Tatsuo, Izuo, Takashi.
Application Number | 20010037779 09/901023 |
Document ID | / |
Family ID | 17988343 |
Filed Date | 2001-11-08 |
United States Patent
Application |
20010037779 |
Kind Code |
A1 |
Iida, Tatsuo ; et
al. |
November 8, 2001 |
Valve driving apparatus provided in an internal combustion
engine
Abstract
The present invention offers a valve driving apparatus provided
in an internal combustion engine. The valve driving apparatus
drives an exhaust valve by using electromagnetic force. The exhaust
valve is movable between an open position and a closed position.
The valve driving apparatus includes an armature coupled with the
exhaust valve, an electromagnetic coil for generating an
electromagnetic force exerted on the exhaust valve, and a control
means for controlling the electromagnetic force applied to the
armature in the direction of the closed position of the exhaust
valve when the exhaust valve is moving to the open position, in the
fuel injection cut control, that is, combustion is suspended in the
internal combustion engine. The present invention also offers a
method for driving the exhaust valve, which comprises the steps of
driving the electric current through the electromagnetic coil,
biasing the armature and controlling the electromagnetic force
applied to the armature.
Inventors: |
Iida, Tatsuo; (Toyota-shi,
JP) ; Izuo, Takashi; (Toyota-shi, JP) ; Asano,
Masahiko; (Toyota-shi, JP) ; Hattori, Hiroyuki;
(Toyota-shi, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW,
GARRETT and DUNNER, L.L.P.
1300 I Street, N.W.
Washington
DC
20005-3315
US
|
Assignee: |
Toyota Jidosha Kabushiki
Kaisha
|
Family ID: |
17988343 |
Appl. No.: |
09/901023 |
Filed: |
July 9, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09901023 |
Jul 9, 2001 |
|
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|
09428494 |
Oct 28, 1999 |
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6279523 |
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Current U.S.
Class: |
123/90.11 ;
251/129.01 |
Current CPC
Class: |
F02D 13/0203 20130101;
F02D 13/0215 20130101; Y02T 10/12 20130101; F02D 13/0249 20130101;
F02D 13/0253 20130101; F01L 9/20 20210101 |
Class at
Publication: |
123/90.11 ;
251/129.01 |
International
Class: |
F01L 009/04; F16K
031/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 29, 1998 |
JP |
HEI. 10-309055 |
Claims
What is claimed is:
1. A valve driving apparatus for driving an exhaust valve, using
electromagnetic force, provided in an internal combustion engine,
said exhaust valve being movable between an open position and a
closed position, said valve driving apparatus comprising: an
armature coupled with said exhaust valve; an electromagnetic coil
for generating an electromagnetic force exerted on said armature; a
valve spring for generating a force exerted on said exhaust valve;
and a control means for controlling the electromagnetic force
applied to said armature in the direction of the closed position of
said exhaust valve when said exhaust valve is moving to the open
position, in the case that combustion is suspended in the internal
combustion engine.
2. The valve driving apparatus according to claim 1, wherein said
control means supplies a canceling electric current for canceling
an electromagnetic force exerted on said armature, for a longer
interval when combustion is suspended in the internal combustion
engine than when combustion is underway in the internal combustion
engine.
3. The valve driving apparatus according to claim 1, wherein said
control means gradually increases a canceling electric current for
canceling the electromagnetic force exerted on said armature after
gradually reducing an electric current for controlling the
electromagnetic force exerted on said armature, when combustion is
suspended in the internal combustion engine.
4. The valve driving apparatus according to claim 1, wherein said
control means controls an electromagnetic force applied to said
armature in the direction of the closed position when said exhaust
valve is moving to the open position after supplying a canceling
electric current for canceling the electromagnetic force exerted on
said armature for an interval, in the case that combustion is
suspended in the internal combustion engine.
5. A valve driving apparatus for driving an exhaust valve, using
electromagnetic force, provided in an internal combustion engine,
said exhaust valve being movable between an open position and a
closed position, said valve driving apparatus comprising: an
armature coupled with said exhaust valve; an electromagnetic coil
for generating an electromagnetic force exerted on said armature; a
valve spring for generating a force exerted on said exhaust valve;
and a valve timing changing means for changing an opening timing of
said exhaust valve, in the case that combustion is suspended in the
internal combustion engine.
6. The valve driving apparatus according to claim 5, wherein the
valve timing changing means changes an opening timing of said
exhaust valve to the advanced timing side.
7. The valve driving apparatus according to claim 5, wherein the
valve timing changing means changes an opening timing of said
exhaust valve to the delayed timing side.
8. A valve driving apparatus for driving an exhaust valve, using
electromagnetic force, provided in an internal combustion engine,
said exhaust valve being movable between an open position and a
closed position, said valve driving apparatus comprising: an
armature coupled with said exhaust valve; an electromagnetic coil
for generating an electromagnetic force exerted on said armature; a
valve spring for generating a force exerted on said exhaust valve;
and a reducing control means for controlling the electromagnetic
force applied to said armature in the direction of the open
position of said exhaust valve when combustion is suspended in the
internal combustion engine less than when combustion is underway in
the internal combustion engine.
9. The valve driving apparatus according to claim 8, wherein said
reducing control means controls the electromagnetic force by
reducing an exciting electric current applied to said
electromagnetic coil.
10. The valve driving apparatus according to claim 8, wherein said
reducing control means reduces the electromagnetic force by
reducing the time of applying an exciting electric current to said
electromagnetic coil.
11. The valve driving apparatus according to claim 8, wherein said
reducing control means reduces the electromagnetic force by
reducing an exciting electric current applied to said
electromagnetic coil and reducing the time of applying an exciting
electric current to said electromagnetic coil.
12. A valve driving apparatus for driving an exhaust valve, using
electromagnetic force, provided in an internal combustion engine,
said exhaust valve being movable between an open position and a
closed position, said valve driving apparatus comprising: an
armature coupled with said exhaust valve; an electromagnetic coil
for generating an electromagnetic force exerted on said armature; a
valve spring for generating a force exerted on said exhaust valve;
and a suspending means for suspending a moving of said exhaust
valve when combustion is suspended in the internal combustion
engine.
13. A method for driving an exhaust valve having an open position
and a closed position, the exhaust valve being associated with an
internal combustion engine, and the exhaust valve being coupled to
an armature, the method comprising the steps of: driving an
electric current through a coil, the coil generating an
electromagnetic force exerted on the armature; biasing the armature
against the electromagnetic force; and controlling the
electromagnetic force applied to the armature in the direction of
the closed position of the exhaust valve when the exhaust valve
moves toward the opening position in the case that combustion is
suspended in the internal combustion engine.
14. The method according to claim 13, further comprising the step
of: supplying a canceling electric current for canceling the
electromagnetic force applied to the armature, for a longer
interval when combustion is suspended in the internal combustion
engine than when combustion is underway in the internal combustion
engine.
15. The method according to claim 13, further comprising the step
of: gradually reducing the electric current for reducing the
electromagnetic force applied to said armature and after that
gradually increasing a canceling electric current for canceling the
electromagnetic force applied to said armature, when combustion is
suspended in the internal combustion engine.
16. The method according to claim 13, further comprising the step
of: increasing an electromagnetic force applied to the armature in
the direction to the closed position when the exhaust valve is
moving to the open position after supplying a canceling electric
current for canceling the electromagnetic force applied to the
armature for an interval, in the case that combustion is suspended
in the internal combustion engine.
17. A method for driving an exhaust valve having an open position
and a closed position, the exhaust valve being associated with an
internal combustion engine, and the exhaust valve being coupled to
an armature, the method comprising the steps of: driving an
electric current through a coil, the coil generating an
electromagnetic force exerted on the armature; biasing the armature
against the electromagnetic force; and changing an opening timing
of the exhaust valve in the case that combustion is suspended in
the internal combustion engine.
18. A method for driving an exhaust valve having an open position
and a closed position, the exhaust valve being associated with an
internal combustion engine, and the exhaust valve being coupled to
an armature, the method comprising the steps of: driving an
electric current through a coil, the coil generating an
electromagnetic force exerted on the armature; biasing the armature
against the electromagnetic force; and reducing the electromagnetic
force applied to the armature in the direction of the open position
of the exhaust valve when the exhaust valve is opening more when
combustion is suspended in the internal combustion engine than when
combustion is underway in the internal combustion engine.
19. A method for driving an exhaust valve having an open position
and a closed position, the exhaust valve being associated with an
internal combustion engine, and the exhaust valve being coupled to
an armature, the method comprising the steps of: driving an
electric current through a coil, the coil generating an
electromagnetic force exerted on the armature; biasing the armature
against the electromagnetic force; and suspending a moving of the
exhaust valve when combustion is suspended in the internal
combustion engine.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a valve driving apparatus
provided in an internal combustion engine. Especially, the valve
driving apparatus drives an exhaust valve by using an
electromagnetic force, and it is appropriate for the exhaust valve
to function to be movable between an open and a closed
position.
BACKGROUND OF THE INVENTION
[0002] A valve driving apparatus which drives an exhaust valve by
using electromagnetic force is already known, as disclosed in
Japanese Laid-Open Patent Application No. 10-18819 or No. 10-18820.
An armature is coupled with an electromagnetic valve (or called
exhaust valve) which is provided in this valve driving apparatus.
On the upper side of the armature, the first electromagnet and an
upper spring are deposited, and on the lower side of the armature,
the second electromagnet and a lower spring are deposited. The
armature is held at the neutral position in the middle between the
first and second electromagnets by the forces of the upper and
lower springs. The electromagnetic valve is full closed when the
armature touches the first electromagnet, and the electromagnetic
valve is full open when the armature touches the second
electromagnet. In the above-mentioned valve driving apparatus, the
exhaust valve is held at the full closed position by the fact that
a predetermined exciting current is supplied to the first
electromagnet and the armature is attracted by the first
electromagnet. When the supply of the exciting current to the first
electromagnet is cut, the armature is pushed by the upper spring
and the exhaust valve begins to move in the opening direction. If a
predetermined exciting current is supplied to the second
electromagnet when the exhaust valve is positioned at a
predetermined position, a damping of displacement amplitude by
friction of the exhaust valve or remaining pressure of combustion
is supplemented and the exhaust valve reaches the full open
position by the fact that the electromagnetic force is supplied to
the armature in the opening direction.
[0003] If the exhaust valve is moving at a high speed when the
exhaust valve arrives at the full open position, that is, the
armature touches the second electromagnet, such problems as
increasing of activating noise of the exhaust valve or bouncing
back of the exhaust valve occur. Therefore, in the aforementioned
valve driving apparatus, the speed of the exhaust valve is
restrained when the exhaust valve approaches to the full open
position, by reducing the exciting current to the second
electromagnet when the exhaust valve reaches near the full open
position.
[0004] Incidentally, in the internal combustion engine installed on
a vehicle, when an accelerator pedal is disengaged during the high
speed driving, for example, a fuel injection cut control for
stopping a fuel injection to a combustion chamber of the engine is
executed. Because combustion does not occur in the process of the
fuel injection cut control, the pressure in the combustion chamber
of the engine is negative (or called vacuum) when the exhaust valve
is at the opening timing, that is, a piston of the engine is near
bottom dead center. This negative pressure forces the exhaust valve
in the opening direction. Consequently, if the same value of the
exciting current is supplied to the second electromagnet in the
execution of the fuel injection cut control, the armature touches
the second electromagnet at the higher speed. Consumed electric
energy increases, because it is necessary to supply the exciting
current again to pull the armature back to the second electromagnet
in order to prevent the armature from bouncing back. Furthermore, a
large noise occurs by the high speed collision between the armature
and the second electromagnet.
SUMMARY OF THE INVENTION
[0005] It is thus one object of the present invention to solve the
aforementioned problems. The present invention provides a valve
driving apparatus for driving an exhaust valve, using
electromagnetic force, provided in an internal combustion engine.
The exhaust valve is movable between an open position and a closed
position. The valve driving apparatus has an armature coupled with
the exhaust valve, an electromagnetic coil for generating an
electromagnetic force exerted on the armature, a valve spring for
generating a force exerted on the exhaust valve, and a control
means. The control means controls the electromagnetic force applied
to the armature in the direction of the closed position of the
exhaust valve when the exhaust valve is moving to open, in the case
that combustion is suspended because of a fuel injection cut
control in the internal combustion engine.
[0006] This control means supplies the electromagnetic force to the
armature coupled with the exhaust valve in the direction of the
closed position, when the exhaust valve is moving to the open
position, in the case that combustion does not occur in the engine.
When combustion is suspended in the engine, negative pressure is
generated in the combustion chamber of the engine at the timing
near the bottom dead center which is the opening timing of the
exhaust valve. The force applied to the exhaust valve by the
negative pressure is canceled by the electromagnetic force in the
direction of the closed position applied to the armature by the
control means. Consequently, the armature is prevented from
colliding with the electromagnet at high speed. Therefore, the
armature does not bounce back from the electromagnet, and the
activating noise of the exhaust valve can be restrained. When
combustion is suspended in the fuel injection cut control, an
engine brake occurs on the basis of the negative pressure of the
combustion chamber. Then, the engine brake is obtained securely by
the present invention.
[0007] The above-mentioned object is achieved by another embodiment
of the present invention. That embodiment is also a valve driving
apparatus for driving an exhaust valve, using electromagnetic
force, provided in an internal combustion engine. The exhaust valve
is movable between an open position and a closed position, in the
same way as depicted in the first embodiment. The valve driving
apparatus has an armature coupled with the exhaust valve, an
electromagnetic coil for generating an electromagnetic force
exerted on the armature, a valve spring for generating a force
exerted on the exhaust valve, and a valve timing changing means.
The valve timing changing means changes an opening timing of the
exhaust valve, in the case that combustion is suspended in the
internal combustion engine.
[0008] Generally speaking, the combustion chamber pressure is
negative near the bottom dead center which is the opening timing of
the exhaust valve, when combustion is suspended in the engine.
However, since the valve timing changing means in this embodiment
changes an opening timing (advanced or delayed) of the exhaust
valve, when combustion is suspended in the engine, the pressure in
the combustion chamber is restrained low negative (that is, near
zero), or becomes positive. Consequently, the armature does not
collide with the electromagnet at high speed. Therefore, it
prevents the armature from bouncing back from the electromagnet,
and the activating noise of the exhaust valve can be restrained.
Since extra electromagnetic force to the armature is not necessary,
electric power can be saved.
[0009] The above-mentioned object is also achieved by another
embodiment of the present invention. That embodiment is also a
valve driving apparatus for driving an exhaust valve, using
electromagnetic force, provided in an internal combustion engine.
The exhaust valve is also movable between an open position and a
closed position. The valve driving apparatus has an armature
coupled with the exhaust valve, an electromagnetic coil for
generating an electromagnetic force exerted on the armature, a
valve spring for generating a force exerted on the exhaust valve,
and a reducing control means. The reducing control means controls
the electromagnetic force applied to the armature in the direction
of the open position of the exhaust valve when combustion is
suspended in the engine less than when combustion is underway in
the engine.
[0010] Since the electromagnetic reducing means controls the
electromagnetic force on the armature in the direction of the open
position of the exhaust valve when combustion is suspended in the
engine less than when combustion is underway in the engine, the
electromagnetic force in the direction of the open position of the
exhaust valve is reduced. Consequently, the armature does not
collide against the electromagnet at high speed. Therefore, the
armature does not bounce back from the electromagnet, and the
activating noise of the exhaust valve can be restrained. Since
extra electromagnetic force to the armature is not necessary,
electric power can be saved. Furthermore, since the combustion
chamber pressure in the engine is negative, therefore the engine
brake can be secured.
[0011] Furthermore, the above-mentioned object is also achieved by
another embodiment of the present invention. That embodiment is
also a valve driving apparatus for driving an exhaust valve, using
electromagnetic force, provided in an internal combustion engine.
The exhaust valve is also movable between an open position and a
closed position. The valve driving apparatus has an armature
coupled with the exhaust valve, an electromagnetic coil for
generating an electromagnetic force exerted on the armature, a
valve spring for generating a force exerted on the exhaust valve,
and a suspending means. The suspending means suspends a moving of
the exhaust valve when combustion is suspended in the engine.
[0012] Since the suspending means suspends a moving of the exhaust
valve when combustion is suspended in the engine, the armature
coupled with the exhaust valve does not collide against a magnet at
high speed. Moreover, an exciting current to the electromagnetic
coil for attracting the armature can be reduced, therefore saving
of an electric power can be attained.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above and other objects, features, advantages and
technical and industrial significance of this invention will be
better understood by reading the following detailed description of
a presently preferred embodiment of the invention, when considered
in connection with the accompanying drawing, in which:
[0014] FIG. 1 is a part of a cross-sectional view of an internal
combustion engine operated by the valve driving apparatus according
to the present invention;
[0015] FIG. 2 is a magnified cross-sectional view of an exhaust
electromagnetic actuator operated by the valve driving
apparatus;
[0016] FIG. 3 is a graph showing characteristics of exciting
current to an upper coil and a lower coil, and showing the position
of the exhaust electromagnetic valve according to the first
embodiment of the present invention;
[0017] FIG. 4 is a graph showing a combustion chamber pressure and
the valve position versus a crank angle of the internal combustion
engine;
[0018] FIG. 5 is a graph showing a characteristic of exciting
current to an upper coil, according to the first embodiment;
[0019] FIG. 6 is a graph showing a characteristic of exciting
current to an upper coil, according to a modified embodiment of the
first embodiment;
[0020] FIG. 7 is a graph showing a characteristic of exciting
current to an upper coil, according to the other modified
embodiment of the first embodiment;
[0021] FIG. 8 is a graph showing a pressure of a combustion
chamber, an exciting current to an upper coil and an exciting
current of a lower coil, and showing a position of an
electromagnetic valve according to the second embodiment of the
present invention;
[0022] FIG. 9 is a graph showing an exciting current to an upper
coil and an exciting current to a lower coil, and showing a
position of an electromagnetic valve according to the third
embodiment of the present invention; and
[0023] FIG. 10 is a graph showing an exciting current to an upper
coil and an exciting current to a lower coil, and showing a
position of an electromagnetic valve according to a modified
embodiment of the third embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] In the following and the accompanying drawings, the present
invention will be described in more detail in terms of the
embodiments. Initially, the basic structure of a control device
concerning this invention is explained. This valve driving
apparatus of the present invention is controlled by an ECU 10, as
shown in FIG. 1. An cylinder block 12 is provided in an internal
combustion engine (hereinafter called only engine), and a cylinder
14 and a water jacket 16 are deposited in the cylinder block 12.
The engine of this embodiment is multi-cylinder internal combustion
engine which includes a plurality of cylinders, however, only one
cylinder 14 is illustrated in FIG. 1.
[0025] A piston 18 is inside the cylinder 14. The piston 18 can
slide and move up-and-down as shown in FIG. 1. A cylinder head 20
is fixed to the cylinder block 12 on the upper side. In each
cylinder head 20, an intake port 22 and an exhaust port 24 are
respectively shaped.
[0026] A combustion chamber 26 is shaped by the lower surface of
the cylinder head 20, the upper surface of the piston 18, and the
side wall of the cylinder 14. The above-mentioned intake port 22
and exhaust port 24 respectively connect to the combustion chamber
26. A valve seat 28 is shaped at the opening edge of the intake
port 22 toward the combustion chamber 26. A valve seat 30 is also
shaped at the opening edge of the exhaust port 24 toward the
combustion chamber 26. The tip of an ignition plug 32 extrudes into
the combustion chamber 26.
[0027] Electromagnetic actuators 38, 40 included in the valve
driving apparatus are deposited in the cylinder head 20. More
specifically, the electromagnetic actuator 38 functions for intake
of fuel and air to the combustion chamber 26, and the actuator 40
functions for exhaust of fuel and air from the combustion chamber
26. As shown in FIG. 1, the intake electromagnetic actuator 38 has
an intake electromagnetic valve 41 and the intake electromagnetic
valve 41 has an intake valve body 42. When the intake valve body 42
touches to and is seated on the valve seat 28, the intake port 22
is closed to the combustion chamber 26. When the intake valve body
42 is apart from the valve seat 28, the intake port 22 connects to
the combustion chamber 26.
[0028] Similarly, as shown in FIG. 1, the exhaust electromagnetic
actuator 40 has an exhaust electromagnetic valve 43 and the exhaust
electromagnetic valve 43 has an exhaust valve body 44. When the
exhaust valve body 44 touches to and is seated on the valve seat
30, the exhaust port 24 is closed to the combustion chamber 26.
When the exhaust valve body 44 is apart from the valve seat 30, the
exhaust port 24 connects to the combustion chamber 26.
[0029] FIG. 2 shows a magnified view of the exhaust electromagnetic
actuator 40. Referring to FIG. 2, the exhaust electromagnetic
actuator 40 has an exhaust electromagnetic valve 43. A lower part
of the exhaust electromagnetic valve 43 is an exhaust valve body
44, and has a shape like a dish placed upside-down. An upper part
of the exhaust electromagnetic valve 43 is a valve stem 62, and has
a shape like a long and slender bar.
[0030] The engine has an intake manifold 46, as shown in FIG. 1.
The intake manifold 46 includes a plurality of pipes connecting a
surge tank 48 to each intake port 22. In each pipe a fuel injection
valve 50 is provided. The fuel injection valve 50 injects fuel into
the pipe on the basis of command signal from the ECU 10.
[0031] An intake pipe 52 connects upstream to the surge tank 48. A
throttle valve 54 is deposited in the intake pipe 52. An air
cleaner 56 connects upstream to the intake pipe 52. Consequently,
outside air filtered by the air cleaner 56 flows into the intake
pipe 52. An exhaust manifold 58 connects to each exhaust port
24.
[0032] A crank angle sensor 60 is provided in the engine. An output
signal from the crank angle sensor 60 is supplied to the ECU 10.The
ECU 10 detects a crank angle CA and an engine revolution speed NE
according to the output signal of the crank angle sensor 60.
[0033] In this embodiment of the present invention, the fuel
injection from the fuel injection valve 50 is controlled to be cut
in the case that an accelerator pedal is disengaged when the
revolution speed NE is higher than a predetermined value. When the
accelerator pedal is disengaged, that is the throttle valve 54 is
closed, a high negative pressure occurs in the surge tank 48, the
intake manifold 46, and the intake port 22 (hereinafter called the
intake system as a whole) downstream from the throttle valve 54.
Incidentally, a high negative pressure means that the difference
from the atmospheric pressure is high and it is low as the absolute
pressure. When the fuel injection is cut under the condition where
an absolute value of negative pressure is high in the intake
system, the pressure in the combustion chamber 26 is negative near
the bottom dead center of the crank angle CA, because combustion
does not occur in the combustion chamber 26. When the negative
pressure occurs in the combustion chamber 26, an engine brake is
generated by a pumping loss of the piston 18 in response to the
negative pressure. In these ways, when the fuel injection cut
control is executed, a negative pressure is generated in the
combustion chamber 26 near the bottom dead center, then the engine
brake is generated in response to the absolute value of the
negative pressure.
[0034] Next, the structure and acting movement of the
electromagnetic actuators 38, 40 is explained as follows. Since the
electromagnetic actuators 38 and 40 have the same structure, only
the electromagnetic actuator 40 is explained as a
representative.
[0035] Referring to FIG. 2, the exhaust valve body 44 connects to
the exhaust valve stem 62. The valve stem 62 is supported movable
up-and-down in the direction of its axis by a valve guide 64 which
is fixed to the cylinder head 20. An armature shaft 66 is coupled
to the valve stem 62 at the upper part. The armature shaft 66 is
shaped as a rod and made of non magnetic materials. At the upper
end of the valve stem 62, a lower retainer 68 is fixed to the valve
stem 62. Beneath the lower retainer 68, a lower spring 70 is
deposited. The lower end of the lower spring 70 touches the
cylinder head 20. The lower spring 70 applies an upward pushing
force to the armature shaft 66 by way of the lower retainer 68 and
the valve stem 62.
[0036] At the end of the armature shaft 66, an upper retainer 72 is
fixed to the armature shaft 66. Above the upper retainer 72, an
upper spring 76 is deposited. In the circumference of the upper
spring 76, a cylindrical upper cap 77 is deposited surrounding the
upper spring 76. An adjust bolt 78, which is coupled to the upper
cap 77 by a screw, touches the upper end of the upper spring 76.
The upper spring 76 applies a downward pushing force to the upper
retainer 72, and the armature shaft 66, as shown in FIG. 2.
[0037] An armature 74 is coupled to the armature shaft 66 in the
middle of the armature shaft 66. The armature 74 is ring-shaped and
made of soft magnetic materials. Above the armature 74, an upper
coil 80 and an upper core 82 are provided. Furthermore, under the
armature 74, a lower coil 84 and a lower core 86 are provided. The
upper coil 84 and the upper core 86 are made of magnetic materials.
The armature shaft 66 is supported in the center part of the upper
core 82 and the lower core 86, being movable up-and-down. The upper
coil 80 and the lower coil 84 connect to a drive circuit which is
not shown. The drive circuit supplies an exciting current to the
upper coil 80 and the lower coil 84 in response to the control
signal from the ECU 10.
[0038] In the outer circumference of the upper core 82 and the
lower core 86, an outer cylinder 88 is provided. The outer cylinder
88 holds the upper core 82 and the lower core 86 a predetermined
distance apart. The aforementioned upper cap 77 is fixed to the
upper surface of the upper core 82. The adjust bolt 78 adjusts the
armature 74 so that the armature 74 is positioned in the middle
between the upper core 82 and the lower core 86.
[0039] In the exhaust electromagnetic actuator 40, the exhaust
valve 43 seats on the valve seat 30, when the armature 74 reaches
and touches the upper core 82. This condition is maintained by
supplying a predetermined exciting current to the upper coil 80.
Hereinafter, the condition where the exhaust valve 43 seats on the
valve seat 30, is called `full closed`, and the position of the
exhaust valve 43 is called `full closed position`.
[0040] When the exciting current is cut to the upper coil 80 in the
condition where the exhaust valve 43 is full closed, the
electromagnetic force applied to the armature 74 vanishes. When the
electromagnetic force 74 applied to the armature 74 vanishes, the
armature 74 moves downward by the spring force of the upper spring
76. If an appropriate exciting current is supplied to the lower
coil 84 when the armature 74 arrives at a predetermined position,
the armature 74 is attracted to the lower core 86 by the
electromagnetic force of the lower coil 84, then the exhaust valve
43 moves downward in FIG. 2.
[0041] When the above-mentioned attractive force is applied to the
armature 74, energy loss by sliding resistance and/or remaining
pressure of combustion is compensated by the attractive force, and
the armature 74 moves downward with the armature shaft 66, the
exhaust valve stem 62, and the exhaust valve body 44. The exhaust
valve 43 continues to move until the armature 74 touches the lower
core 86. Hereinafter, the condition where the armature 74 touches
the lower core 86, is called `full open`, and the position of the
exhaust valve 43 is called `full open position`. This full open
condition is maintained by supplying a predetermined exciting
current to the lower coil 84.
[0042] When the exciting current applied to the lower coil 84 is
cut off, in the condition where the exhaust valve 43 is kept at the
full open position, the electromagnetic force applied to the
armature 74 vanishes. When the electromagnetic force to the
armature 74 is extinguished, the armature 74 moves upward in FIG.
2, by the spring force of the lower spring 70. If an appropriate
exciting current is supplied to the upper coil 80 when the armature
74 reaches a predetermined position, the armature 74 is in this
case attracted to the upper core 82 by the electromagnetic force of
the upper coil 80. Then, the exhaust valve 43 moves upward in FIG.
2.
[0043] When the above-mentioned attractive force is applied to the
armature 74, energy loss by sliding resistance and/or other is
compensated by the attractive force, and the armature 74 moves
upward with the exhaust valve 43. The exhaust valve 43 moves until
the armature 74 touches the upper core 82, that is the full closed
position.
[0044] Concerning the exhaust electromagnetic actuator 40 as
mentioned above, not only can the exhaust valve 43 be moved toward
the full closed position by supplying a predetermined exciting
current to the upper coil 80, but the exhaust valve 43 can also be
moved toward the full open position by supplying a predetermined
exciting current to the lower coil 84. Therefore, the exhaust valve
43 can be moved reciprocally between the full open and full closed
positions, by supplying the exciting current alternately to the
lower and upper coils 84, 80.
[0045] The intake electromagnetic actuator 38 including the intake
valve 41 also behaves in the same manner as the aforementioned
exhaust electromagnetic actuator 40. Consequently, according to
this embodiment of the present invention, the intake valve 41 and
exhaust valve 43 can be driven toward the full open and full closed
position at any predetermined timing by supplying the control
signal to the drive circuit from the ECU 10 so that the exciting
current to the upper coil 80 and the lower coil 84 is alternately
applied at the appropriate timing in the electromagnetic actuators
38, 40. (cf. The intake electromagnetic actuator 38 has the same
number for the including parts as the actuator 40, except 41,
42.)
[0046] A rather big activating noise, however, occurs when the
armature 74 collides with the lower core 86 or the upper core 82,
in the case that the intake valve 41 and/or the exhaust valve 43
move at a high speed when the armature 74 touches the lower core 86
or the upper core 82. Furthermore, the armature 74 bounces back
from the lower core 86 or the upper core 82, when the armature 74
collides the lower core 86 or the upper core 82 at the high speed.
In this case, the extra exciting current must be supplied in order
to attract the armature 74 again to the lower core 86 or the upper
core 82. Consumed energy of the electromagnetic actuators 38, 40,
then, increases inevitably. Consequently, it is desirable that the
exciting current applied to the lower and upper coils 84, 80 is
controlled so that the intake and exhaust valves 41, 43 move at a
slow speed when they reach the full open and full closed
positions.
[0047] From the above-mentioned viewpoint, the exciting current
supplied to the upper coil 80 in order to drive the valves 41, 43
open-closed is shown, responding to elapsed time, in the upper
graph of FIG. 3. The exciting current supplied to the lower coil 84
is also shown in the middle graph in FIG. 3. Furthermore, the valve
position of the intake valve 41 or exhaust valve 43 corresponding
to the exciting currents of the upper and lower coils is shown in
the bottom graph of FIG. 3.
[0048] As shown in the top figure of FIG. 3, the exciting current
applied to the upper coil 80 is kept constant at the value of
I.sub.MAX (called attracting current) during a predetermined
interval A, when the valve 41 or 43 moves from the full open
position to the full closed position. After the interval A, the
attracting current I.sub.H begins to decrease, when the valve 41 or
43 nearly reaches the full closed position, and becomes the value
of I.sub.H (called holding current) during a changing interval B.
After the changing interval B, the holding current I.sub.H which is
lower than the attracting current I.sub.MAX is maintained during a
predetermined interval C. When the valve 41 or 43 is indicated to
be open, a negative value of the exciting current I.sub.R (called
canceling current), which is opposite against the attracting
current I.sub.MAX and the holding current I.sub.H, is kept in a
predetermined interval D. Incidentally, the interval D, in which
the canceling current is I.sub.R is supplied, is set so that the
remaining electromagnetic field applying the armature 74 can be
canceled.
[0049] Similarly, as shown in the middle graph of FIG. 3, the
exciting current applied to the lower coil 84 is kept constant
value I.sub.MAX (also called attracting current) during a
predetermined interval A, when the valve 41 or 43 moves from the
full closed position to the full open position. After the interval
A, the attracting current I.sub.MAX begins to decrease toward a
holding current I.sub.H during a changing interval B. After the
changing interval B, the holding current I.sub.H is maintained
during a predetermined interval C. When the valve 41 or 43 is
indicated to be closed, the canceling current I.sub.R is kept in a
predetermined interval D.
[0050] The ECU 10 supplies the above-mentioned current to the upper
coil 80 and the lower coil 84 at the synchronizing timing to the
crank angle CA, on the basis of the output signal of the crank
angle sensor 60. Consequently, the intake valve 41 and exhaust
valve 43 can be driven open or closed at the appropriate timing,
synchronizing the operation of the engine.
[0051] As mentioned above, when the accelerator pedal is disengaged
at a high revolution speed of the engine, the fuel injection cut
control is executed. The negative pressure, then, occurs in the
combustion chamber 26 near the bottom dead center of the crank
angle CA. The upper graph in FIG. 4 shows pressure in the
combustion chamber versus the crank angle CA. The solid line shows
the pressure in the case that the fuel injection cut control is not
executed, that is in the normal operation, and the dotted line
shows the pressure in the case that the fuel injection cut control
is executed. In the lower graph in FIG. 4, the solid line shows the
position of the exhaust valve 43 when it moves from the full closed
position toward the full open position in the normal operation of
the engine, and the dotted line shows the position of the exhaust
valve 43 in the case that the same value of the exciting current as
in the normal driving condition (where the fuel is injected into
the combustion chamber 26) is applied.
[0052] As shown by the solid line in the upper graph of FIG. 4, the
combustion chamber pressure becomes very high by the ignition near
the top dead center when the operation of the engine is normal.
Even at the bottom dead center, the combustion chamber pressure is
maintained positive because the positive pressure remains in the
combustion chamber 26. As shown by the dotted line in the upper
graph of FIG. 4, the combustion chamber pressure only changes by
expansion and compression in the combustion chamber 26, the
combustion chamber pressure decreases to the negative pressure near
the bottom dead center.
[0053] Referring to the lower graph in FIG. 4, the exhaust valve 43
begins to open near the bottom dead center. Corresponding to this,
the combustion chamber pressure is positive Pa at the opening
timing of the exhaust valve 43, as shown by the solid line in the
upper graph in FIG. 4, in the normal driving condition, therefore
the attracting force is not applied to the exhaust valve 43 caused
by the combustion chamber pressure. Therefore, the moving speed of
the exhaust valve 43 is restrained low when it reaches the full
open position, as shown in the lower graph of FIG. 4, and problems
of the bouncing back or activating noise of the armature 74 can be
avoided.
[0054] On the other hand, during the fuel injection cut control,
the combustion chamber pressure is negative Pb when the exhaust
valve 43 is the opening timing, as shown by the dotted line in the
upper graph of the FIG. 4. Consequently, if the exhaust valve 43 is
driven to open at the same timing as the normal operation of the
engine when the fuel injection cut control is executed, the force
in the direction to open the exhaust valve 43 is applied by the
negative pressure of the combustion chamber 26. Therefore, the
force caused by the negative pressure of the combustion chamber 26
becomes surplus, when the same value of the exciting current as in
the normal driving condition is applied to the lower coil 84 in the
middle graph of FIG. 3.
[0055] Thus, the armature 74 moves and touches the lower core 86 at
high speed, when the exhaust valve 43 reaches the full open
position and the exhaust valve 43 bounces back from the full open
position as shown in the lower graph of FIG. 4. In this case, it is
necessary that the excess exciting current is supplied to the lower
coil 84 in order to attract again the armature 74 to the lower core
86, therefore, the consumed energy increases and the noise problem
occurs because the armature 74 collides with the lower core 86 at
high speed, as mentioned above. Furthermore, when the armature 74
collides with the lower core 86 at high speed, a friction wear of
both parts and/or other parts might occur, because impact force is
applied to parts of the exhaust electromagnetic actuator 40.
[0056] In this embodiment, however, the above-mentioned trouble can
be avoided, because the electromagnetic force in the closing
direction of the closed position is added to the armature 74 when
the exhaust valve 43 is opening, during the fuel injection cut
control.
[0057] FIG. 5 shows the magnified view of the wave of the interval
D in the top graph of FIG. 3, that is, canceling current I.sub.R
which is supplied to the upper coil 80 of the exhaust
electromagnetic actuator 40 when the exhaust valve 43 begins to
open from the full closed position in the fuel injection cut
control. The canceling current I.sub.R in the normal driving
condition is shown as the chain line in FIG. 5.
[0058] As shown in FIG. 5, the interval T1 during which the
canceling current I.sub.R is supplied in the fuel injection cut
control, is longer than the interval T0 in the normal driving
condition. As mentioned above, the interval D=T0 in the normal
driving condition is set so that the remaining magnetism on the
armature 74 can be erased just during the interval T0. Since the
interval D is set T1 which is longer than T0 in this embodiment,
the canceling current I.sub.R continues to be supplied to the upper
core 82, even after the remaining magnetism on the armature 74 is
erased. The electromagnetic force is furthermore applied between
the armature 74 and upper core 82 by this exciting current I.sub.R
during the time between (T1-T0). Therefore, the opening force of
the exhaust valve 43 caused by the negative pressure in the
combustion chamber 26 can be canceled. Accordingly, in the fuel
injection cut control the armature 74 can be prevented from
colliding with the lower core 86 at high speed, and the colliding
noise which occurs when the armature 74 runs against the lower core
86 can be restrained. Moreover, the consumed energy of the exhaust
electromagnetic actuator 40 can be saved, because it is not
necessary that the armature 74 is again attracted to the lower core
86 after the armature 74 bounces back from the lower core 86.
[0059] Incidentally, the negative pressure in the combustion
chamber 26 is certainly obtained in the fuel injection cut control,
because the opening timing of the exhaust valve 43 in the fuel
injection cut control is the same as one in the normal driving
condition, in this embodiment. As mentioned above, the engine brake
of the vehicle occurs on the basis of the negative pressure of the
combustion chamber 26, when the fuel injection cut control is
executed. Consequently, the aforementioned advantages can be
attained while still securing the engine brake in the fuel
injection cut control.
[0060] In the fuel injection cut control, the greater the absolute
value of the negative pressure in the combustion chamber 26 is, the
greater the opening force applied to the exhaust valve 43 is.
Furthermore, the higher the revolution speed NE of the engine is,
the greater the absolute value of the negative pressure, in the
fuel injection cut control. Consequently, by estimating the
negative pressure of the combustion chamber 26 on the basis of the
revolution speed NE and making the interval D (during D the
exciting current I.sub.R is supplied) longer according to the
increase of the absolute value of the negative pressure, the
collision noise of the armature 74 can be prevented from increasing
and the consuming electric power caused by the bouncing of the
armature 74 can be restrained. For example, even when the
revolution speed NE is high and the absolute value of the negative
pressure is large, the above-mentioned merits can be obtained by
setting the longer interval D according to the condition of the
revolution speed NE and the negative pressure.
[0061] Incidentally, in this embodiment the force to the exhaust
valve 43 in the direction of the closed position is applied by
elongating the interval D so that the force to the exhaust valve 43
in the direction of the open position responding to the negative
pressure is canceled.
[0062] The exciting current shown in the graph FIG. 6 or FIG. 7 can
also be adopted. FIG. 6 shows the exciting current which is
controlled to decrease gradually. In this case, the electromagnetic
attracting force between the armature 74 and the upper core 82 is
greater than the force in the case where the exciting current
decreases step-wise, because the electromagnetic force between the
armature 74 and the upper core 82 gradually reduces. Therefore, the
opening force applied to the exhaust valve 43 caused by the
negative pressure in the combustion chamber 26 can be canceled by
the increase of the closing force applied to the exhaust valve
43.
[0063] FIG. 7 shows the wave of the exciting current which is
supplied the upper coil 80 by the positive current I.sub.p after
being supplied by the negative current I.sub.R. In this case, the
electromagnetic attracting force is applied between the armature 74
and the upper core 82 by the positive current I.sub.p. The closing
force applied to the armature 74 increases by the value of the
above-mentioned electromagnetic force. Accordingly, the opening
force applied to the exhaust valve 43 caused by the negative
pressure in the combustion chamber 26 can be canceled.
[0064] In this embodiment, the ECU 10 supplies the canceling
current I.sub.R which is shown in FIG. 5, 6 or 7 to the upper coil
80. This means that a control means for controlling the
electromagnetic force applied to the armature is realized.
[0065] Incidentally, in this embodiment the current direction of
the canceling current I.sub.R is opposite to the direction of the
attracting current I.sub.MAX, however, it is not necessarily
limited to this case, and the canceling current I.sub.R can also be
zero. In this case, in the fuel injection cut control the wave of
the exciting current I.sub.R=0 in FIG. 6 or 7 is given, when the
armature 74 is taking apart from the upper core 82.
[0066] Next, the second embodiment is explained. In the second
embodiment, the opening valve timing of the exhaust valve 43 in the
fuel injection cut control is changed from the condition in the
normal driving control, in the same system as shown in FIGS. 1 and
2.
[0067] The upper graph in FIG. 8 shows the pressure in the
combustion chamber 26 vs. the crank angle CA of the engine in the
fuel injection cut control, in the same manner as the
above-mentioned upper graph in FIG. 4. The characteristics is,
however, illustrated in the upper graph in FIG. 8 in the hypothesis
that the exhaust valve 43 is kept at the full closed position.
[0068] The second and third graphs from the top in FIG. 8 show the
exciting current to the upper coil 80 and to the lower coil 84 of
the exhaust electromagnetic actuator 40. In these two graphs the
exciting current patterns X and Y are shown respectively by the
solid line and the chained line, and the exciting current supplied
to the upper and lower coils 80, 84 in the normal driving condition
is shown by the dotted line.
[0069] In the lower graph of FIG. 8, the solid line shows the
position of the exhaust valve 43 given by the exciting current of
the pattern X, the chained line shows the position given by the
pattern Y, and the dotted line shows the position in the normal
driving condition.
[0070] In the fuel injection cut control, as shown in FIG. 8, the
opening timing of the exhaust valve 43 is more advanced (the
pattern X) or more delayed (the pattern Y) than in the normal
driving control. Consequently, the exhaust valve 43 is prevented
from opening in the condition where the negative pressure occurs in
the combustion chamber 26. Referring to the upper graph of FIG. 8,
in the fuel injection cut control, the combustion chamber pressure
is negative near the bottom dead center, and on other hand the
pressure is positive in the other range. In this embodiment, the
exciting current I.sub.R is supplied to the upper coil 80 to open
the exhaust valve 43 (shown in the second graph of FIG. 8) in the
condition, where the combustion chamber pressure is positive or is
slightly negative such as the armature 74 can not bounce back
against the lower core 86. Accordingly, the exhaust valve can be
prevented from being forced to open by the negative pressure of the
combustion chamber 26. Therefore, it can be avoided that the
actuating noise of the exhaust electromagnetic valve 40 increases
and the armature 74 bounces back from the lower core 86.
[0071] Incidentally, in this embodiment the aforementioned
advantages are obtained by changing the opening timing of the
exhaust valve 43. That is, this does not require the armature 74 to
be given the electromagnetic force in order to cancel the force
caused by the negative pressure of the combustion chamber 26.
Therefore, the consumed electric power of the exhaust
electromagnetic actuator 40 can be restrained.
[0072] In the second embodiment, the ECU 10 supplies the exciting
current shown pattern X or Y in FIG. 8 to the upper coil 80 and the
lower coil 84 in the fuel injection cut control, thus, a valve
timing changing means is realized.
[0073] Next, the third embodiment is explained. In the third
embodiment, in the fuel injection cut control, the force to the
exhaust valve 43 in the opening direction caused by the negative
pressure in the combustion chamber 26 is canceled by means of
restraining or nullifying the electromagnetic force in the opening
direction to the armature 74, when the exhaust valve 43 begins to
open, in the same system as shown in FIG.1 and 2.
[0074] The exciting current supplied to the upper coil 80 of the
exhaust electromagnetic actuator 40 is shown in the upper graph in
FIG. 9,. The exciting current to the lower coil 84 is shown in the
middle graph, and the position of the exhaust valve 43 is shown in
the lower graph. The solid line shows the fuel injection cut
control, and the dotted line shows the normal driving control.
[0075] With reference to the middle graph of FIG. 9, in the fuel
injection cut control, the supplying timing of the attracting
current I.sub.MAX to the lower coil 84 in the opening process of
the exhaust valve 43 is delayed comparing with the timing in the
normal driving control. Furthermore, the attracting current
I.sub.MAX is restrained to be lower. In this embodiment, the
canceling current I.sub.R is immediately supplied without supplying
the holding current I.sub.H, and by advancing the beginning timing
of supplying the attracting current I.sub.MAX to the upper coil 80,
the exhaust valve 43 is forced to move toward the closed position
without being kept at the full open position.
[0076] Since the timing of supplying the attracting current
I.sub.MAX to the lower coil 84 is delayed and the value I.sub.MAX
is limited to be lower, the kinetic energy of the exhaust valve 43
is decreased. By the decrease of the kinetic energy, the high speed
colliding noise between the armature 74 and the lower core 86 can
be reduced and it can be avoided that the armature 74 bounces back
from the lower core 86.
[0077] Next, the modified example of the third embodiment is
explained. The upper graph of FIG. 10 shows the exciting current
supplied to the upper coil 80 of the exhaust electromagnetic
actuator 40 when the exhaust valve 43 begins to open in the fuel
injection cut control. The middle graph depicts the exciting
current supplied to the lower coil 84, and the lower graph shows
the position of the exhaust valve 43. In these graphs the solid
lines indicate the waves in the fuel injection cut control, and the
dotted lines indicate the waves in the normal driving control.
[0078] In this case, since the timing of supplying the attracting
current I.sub.MAX to the lower coil 84 is delayed and the value of
the attracting current I.sub.MAX is restrained to be low in the
same manner as in the aforementioned third embodiment, the force
applied to the exhaust valve 43 in the opening direction caused by
the negative pressure in the combustion chamber 26 is canceled.
Furthermore, since the holding exciting current I.sub.H to the
lower coil 84 is supplied following the supply of the attracting
current I.sub.MAX, the exhaust valve 43 can be kept at the full
open position.
[0079] In these third and modified embodiments, in the fuel
injection cut control, the beginning timing of supplying the
attracting current I.sub.MAX to the lower coil 84 is delayed and
the attracting current I.sub.MAX is restrained low, and
consequently the kinetic energy given to the armature 74 is
reduced. The invention, however, is not limited to the
above-mentioned embodiments. For example, the method of only
delaying the supplying timing of the attracting current I.sub.MAX
or the method of only restraining the attracting current I.sub.MAX
to be low, can be adopted. Moreover, if the absolute value of the
negative pressure of the combustion chamber 26 is large, the method
that the exciting current supplied to the lower coil 84 is zero can
be available, in this case the exhaust valve 43 is opened by the
force caused by the negative pressure of the combustion chamber
26.
[0080] Incidentally, when the absolute value of the negative
pressure in the combustion chamber 26 is large and the armature 74
moves toward the lower core 86 at the high speed, even if the
attracting current I.sub.MAX is not supplied to the lower coil 84,
the problems of the colliding noise between the armature 74 and the
lower core 86 or the bounce back of the armature 74 can not be
avoided completely. From this point of view, the methods explained
in the third and modified embodiments are effective when the
absolute value of the negative pressure in the combustion chamber
26 is rather low.
[0081] In the above-mentioned third and its modified embodiments,
since the exciting current shown in the middle graph of FIG. 9, or
in the middle graph of FIG. 10 is supplied to the lower coil 84 in
the fuel injection cut control, a reducing control means for
controlling the electromagnetic force applied to the armature 74 is
realized.
[0082] Next, the fourth embodiment is explained. In this
embodiment, the ECU maintains the supply of the holding current
I.sub.H to the upper coil 80 of the exhaust electromagnetic
actuator 40 in the fuel injection cut control, so that the exhaust
valve 43 is kept at the full closed position. Accordingly, the
exhaust valve 43 does not move toward the opening side in the fuel
injection cut condition. Therefore, the aforementioned problems
caused by the collision between the armature 74 and the lower core
86 are avoided. Furthermore, it is not necessary to supply the
attracting exciting current I.sub.MAX to the lower coil 84, because
it is enough to supply the holding current I.sub.H to the upper
coil 80 of the exhaust electromagnetic actuator 40 in order to hold
the exhaust valve 43 at the full closed position. Incidentally, in
this case, the engine brake becomes rather low by the fact that the
exhaust valve 43 is kept at the full closed position. Consequently,
in this embodiment more saving of electric power for the exhaust
electromagnetic actuator 40 can be achieved than in the third or
its modified embodiment.
[0083] The exhaust valve 43 is kept at the full closed position in
the fourth embodiment, however, it is not limited to this method.
That is, it is also available that the exhaust valve 43 is kept at
the full open position by supplying the holding current I.sub.H to
the lower coil 84. Moreover, it is also available that the exhaust
valve 43 is held at the neutral position by supplying the exciting
current neither to the upper coil 80 nor the lower coil 84 when the
fuel injection cut control is executed. In this case, more electric
power saving can be attained.
[0084] A suspending means for suspending a moving of the exhaust
valve 43 is realized by the fact that the ECU 10 maintains the
supply of the holding current I.sub.H to the upper coil 80 or the
lower coil 84 or suspends the supply of the exciting current to
both coils 80 and 84, in the fuel injection cut control.
[0085] Other embodiments of the invention will be apparent to those
skilled in the art from consideration of the specification and
practice of the invention disclosed herein. It is intended that the
specification and examples be considered as exemplary only, with
the true scope and spirit of the invention being indicated by the
following claims.
* * * * *