Electromagnetically actuated intake or exhaust valve for an internal combustion engine

An intake or exhaust valve for an internal combustion engine includes a valve member having a head and a stem extending from the head, the head of the valve member being capable of forming a seal with a valve seat of the internal combustion engine, an electromagnetic actuator for moving the valve member axially from a closed position wherein the head forms a seal with the valve seat and an open position wherein the head is spaced from the valve seat to permit flow between the head and the valve seat, and an actuator controller for selectively activating the electromagnetic actuator to control movement of the valve member. The intake or exhaust valve includes a dampener for limiting closing speed of the valve member.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an intake or exhaust valve for an internal 
combustion engine. More particularly, the present invention relates to an 
intake or exhaust valve opening and closing apparatus having an 
electromagnetic coil to close or open the valve in response to a signal 
from a controller. 
2. Description of Related Art 
Generally, an internal combustion engine of an automobile has intake and 
exhaust valves for controlling intake of an air fuel mixture and exhaust 
of combustion byproducts, respectively, by opening and closing the intake 
and exhaust valves. 
As shown in FIG. 4, a cylinder head 1' of a conventional engine is provided 
with an intake or exhaust valve member 2' (hereinafter, simply referred to 
as "valve member") for closing or opening an intake or exhaust port 3' 
(hereinafter, simply referred to as "port"), a valve stem guide 4' 
attached to the cylinder head 1', a valve spring 6' between the cylinder 
head 1' and a spring supporting plate 5' attached to an upper portion of 
the valve member 2', a lash adjuster 7' disposed at an upper portion of 
the valve member 2', and a cam 8' disposed above the lash adjuster 7'. 
When the cam 8' rotates, the cam 8' contacts the lash adjuster 7' and 
reciprocates the valve member 2' between a closed position and open 
position. The valve stem guide 4' guides movement of the valve member 2' 
and the valve spring 6' biases the valve member 2' toward the cam 8' into 
the closed position. The lash adjuster 7' automatically adjusts valve 
clearance. 
As the cam 8' rotates to perform an intake or exhaust stroke, the valve 
member 2' moves to the open position and intake of the air fuel mixture or 
exhaust of the combustion byproducts takes place through the port 3', 
while the valve spring 6' is resiliently compressed. 
After completing either the intake or exhaust stroke, the cam 8' continues 
to rotate and performs a compression or ignition stroke, where the cam 8' 
releases pressure applied to the lash adjuster 7' and allows the valve 
spring 6' to expand. The valve member 2' ascends, thereby closing the port 
3', and at the same time, lifting the lash adjuster 7' to return to an 
initial position. 
Various parts, such as the valve stem guide 4', spring supporting plate 5', 
valve spring 6', lash adjuster 7', cam 8', and so forth, are required to 
open or close the valve member 2'. This mechanism reduces efficiency and 
is complicated. In addition, this conventional structure adds weight to a 
vehicle and requires a large cylinder head 1'. 
FIG. 5 shows valve lift taking place while the cam 8' rotates through 
different crank angles. In the above-mentioned conventional structure, the 
outer profile and rotation of the cam 8' determine the timing and duration 
for the opening and closing of the valve member 2'. Therefore, the valve 
timing and duration are designed for high engine power at fast rotational 
speeds. However, at slower rotational speeds of the engine this causes 
poor fuel economy, reduced performance, increased exhaust gas, and reduced 
stability at idling. 
In light of the foregoing, there is a need in the art for an improved 
valve. 
SUMMARY OF THE INVENTION 
Accordingly, the present invention is directed to a valve that 
substantially obviates one or more of the limitations of the related art. 
In particular, the present invention is directed to an intake or exhaust 
valve having an electromagnetic actuator to close or open the intake or 
exhaust valve in response to a signal from a controller. Preferably, the 
invention facilitates control of the valve operating timing based on 
conditions of the engine, thereby providing reduced fuel consumption, 
improved performance and idling stability, reduction of exhaust gas, and 
structural simplicity allowing for a smaller cylinder head. 
To achieve these and other advantages and in accordance with the purposes 
of the invention, as embodied and broadly described herein, the invention 
includes an intake or exhaust valve for an internal combustion engine, 
comprising a valve member having a head and a stem extending from the 
head, the head of the valve member being capable of forming a seal with a 
valve seat of the internal combustion engine, an electromagnetic actuator 
for moving the valve member axially from a closed position wherein the 
head forms a seal with the valve seat and an open position wherein the 
head is spaced from the valve seat to permit flow between the head and the 
valve seat, and an actuator controller for selectively activating the 
electromagnetic actuator to control movement of the valve member. 
In another aspect, an electronic controller is provided for controlling the 
actuator controller in response to conditions of the engine. 
In a further aspect, a dampener is provided for limiting closing speed of 
the valve member. 
It is to be understood that both the foregoing general description and the 
following detailed description are exemplary, and are intended to provide 
further explanation of the invention as claimed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Reference will now be made in detail to the present preferred embodiment of 
the invention, an example of which is illustrated in the accompanying 
drawings. Wherever possible, the same reference numbers are used in the 
drawings and the description to refer to the same or like parts. 
As shown in FIG. 1 and FIG. 2, an intake or exhaust valve for an internal 
combustion engine includes a valve member 20 for opening or closing an 
intake or exhaust port 11 (referred to as valve port) of a cylinder head 
10, an electromagnetic actuator 30 attached to an upper portion of the 
cylinder head 10, a dampener 40 attached to the electromagnetic actuator 
30, an electronic controller 50 for determining the operational conditions 
of an engine and controlling the timing of valve closing or opening, and 
an actuator controller 60 for activating the electromagnetic actuator 30 
at proper intervals based on signals from the electronic controller 50. 
The electromagnetic actuator 30 electromagnetically moves the valve member 
20 in response to electric signals from the actuator controller 60. As 
described in more detail below, the dampener 40 hydraulically reduces 
closing speed of the valve member 20 to prevent damage to the valve member 
20, which may occur due to impact against the cylinder head 10 during 
closing of the valve member 20. 
As shown in FIG. 2, the valve member 20 includes a head 22 and a stem 24 
extending from the head 22. An entrance of the valve port 11 in the 
cylinder head 10 has a valve seat 12 which comes in contact with the head 
22 of the valve member 20 to form a seal when the valve member 20 is 
closed. 
The electromagnetic actuator 30 includes a housing 31 on the cylinder head 
10, upper and lower electromagnetic coils 32 and 33 in upper and lower 
portions of the housing 31, an armature 34 positioned in a middle portion 
of the housing 31, and upper and lower elastic members 35 and 36 on 
opposite sides of the armature 34. 
The upper and lower electromagnetic coils 32 and 33 each generate magnetic 
fields in response to signals from the actuator controller 60. The 
armature 34 is connected to the stem 24 and magnetically attached by the 
magnetic fields generated by the electromagnetic coils 32 and 33 to open 
and close the valve member 20. The elastic members 35 and 36 return the 
armature 34 to a neutral position and create a biasing force for returning 
the valve member 20 from the open position to the closed position. 
The valve stem guide 70 is attached to both the housing 31 and the cylinder 
head 10. The valve stem guide 70 guides the stem 24 of valve member 20 
when the valve member 20 moves upward and downward during valve opening 
and closing. 
An upper spring seat 37 is formed in an upper portion of the housing 31 to 
support the upper elastic member 35 between the upper spring seat 37 and 
the armature 34. A lower spring seat 38 is formed in a lower portion of 
the housing 31 and attached to the valve stem guide 70. The lower spring 
seat 38 supports the lower elastic member 36 between the lower spring seat 
38 and the armature 34. The upper and lower spring seats 37 and 38 prevent 
fluctuation of the elastic members 35 and 36. 
The upper and lower elastic members 35 and 36 are designed so that a 
biasing force of the lower elastic member 36 is greater than a biasing 
force of the upper elastic member 35. This biases the valve member 20 
toward the closed position and ensures that the head 22 forms a seal with 
the valve seat 12 in the closed position. 
Preferably, the upper and lower elastic members 35 and 36 are springs. 
However, any component capable of applying a biasing force may be used. 
The dampener 40 has a chamber body 41 and a piston 42 slidable in a sealed 
manner along an inner wall surface of the chamber body 41. The chamber 
body 41 is attached to an upper surface of the housing 31 of the 
electromagnetic actuator 30 and includes an interior 411 for containing 
oil supplied to the chamber body 41 via an opening at a lower portion of 
the dampener 40 communicating with an oil tube 43 connected to an oil pump 
(not shown). 
The chamber body 41 includes a return oil flow passage 413 extending 
between upper and lower portions of the chamber body 41 so that the oil in 
the interior 411 can be circulated. The piston 42 is attached to an upper 
portion of the stem 24 of valve member 20 and adjusts speed of the valve 
member 20 during the opening or closing of the valve member 20. As shown 
in FIG. 2, the piston 42 has wall 421 isolating an upper compartment of 
the dampener 40 from a lower compartment of the dampener 40. An orifice 
422 formed at a central portion of the wall 421 allows restricted flow of 
the oil between the compartments. 
The chamber body 41 also has an air exhausting hole 414 formed in an upper 
portion thereof, for exhausting air which may be contained in the oil. 
An upper portion of the housing 31 includes an oil seal 39 surrounding a 
portion of the stem 24, for preventing leakage of the oil from the 
dampener 40 when the stem 24 slides in the seal 39. 
The electronic controller 50 determines operating conditions of an internal 
combustion engine, such as the engine speed, load, etc., and then 
calculates the proper timing for the closing or opening of the valve 
member 20. 
The actuator controller 60 opens or closes the valve member 20 by supplying 
electric power to the upper and lower electromagnetic coils 32 and 33 of 
the electromagnetic actuator 30, respectively, at determined times. 
After an engine is started, the actuator controller 60 supplies power from 
a power source (not shown) to the magnetic actuator 30 in response to 
valve opening or closing control signals from the electronic controller 
50. 
If the actuator controller 60 receives an opening signal from the 
electronic controller 50, electric current is applied to the lower 
electromagnetic coil 33 of the electromagnetic actuator 30, thus causing 
the lower electromagnetic coil 33 to produce a magnetic field attracting 
the armature 34. This lowers the armature 34 toward the lower 
electromagnetic coil 33 and lowers the valve member 20 to open the valve 
port 11. 
When the armature 34 is moved downward in response to the magnetic field, 
the lower elastic member 36 resiliently compresses, while the upper 
elastic member 35 resiliently elongates. 
When the valve member 20 descends, the piston 42 in the dampener 40 also 
descends. The oil contained in the interior 411 of the chamber body 41 is 
compressed in the lower area of the interior 411 as the piston 42 moves. 
This oil flows toward the upper side of the chamber body 41 through the 
oil flow passage 413 and through the orifice 422 in the wall 421. 
Therefore, the piston 42 quickly descends to allow for rapid opening of the 
valve member 20. 
When the actuator controller 60 receives a closing signal from the 
electronic controller 50, electric current is applied to the upper 
electromagnetic coil 32 of the electromagnetic actuator 30. This causes 
the upper electromagnetic coil 32 to produce a magnetic field attracting 
the armature 34, while the lower electromagnetic coil 33 is deactivated. 
The armature 34 moves toward the upper magnetic coil 32 from the lower 
magnetic coil 33 so that the valve member 20 rises to close the valve port 
11. 
When the armature 34 moves upwards due to the magnetic field, the upper 
elastic member 35 resiliently compresses and the lower elastic member 36 
resiliently elongates. 
When the valve member 20 rises to the closed position, the piston 42 in the 
dampener 40 slides upwards. Oil in an upper portion of the interior 411 of 
the chamber body 41 is compressed and flows toward the lower end of the 
interior 411 through the oil flow passage 413. The shape of orifice 422 
formed in the wall 421 restricts flow through the orifice 422 to dampen 
upward movement of the piston 42. This dampened movement of the piston 42 
allows the valve member 20 to be closed gently, preventing abrupt impact 
between the head 22 and the valve seat 12 of the cylinder head 10. 
The electronic controller 50 determines whether the engine is starting, 
idling, or operating at a particular speed and load to facilitate timing 
of the opening and closing of the valve member 20, and send the 
appropriate control signal to the actuator controller 60 so that the 
electromagnetic actuator 30 properly opens or closes the valve member 20. 
As shown in FIG. 3(A), when the engine is at low speed, the time duration 
necessary for opening the valve member 20 and an overlapped time duration 
can be reduced. As shown in FIG. 3(B), when the engine is at high speed, 
the time duration necessary for opening the valve member 20 can be 
maintained satisfactorily, such that performance and power of the engine 
are improved. In addition, this guarantees stability during idling and 
reduces both fuel consumption and exhaust gas. 
The present invention allows for the elimination of some conventional parts 
employed for closing or opening of conventional valves. This structural 
simplicity allows for ease of assembly and the use of a small-sized 
cylinder head 10, reducing weight of a vehicle significantly, and thereby 
decreasing fuel consumption. 
Since the invention has electromagnetic coils for closing or opening the 
intake or exhaust valve in response to the signal from the controller, it 
facilitates control of the timing based upon conditions of the engine, 
thereby providing reduced fuel consumption, improved performance and 
idling stability, reduced exhaust gas, and structural simplicity of a 
smaller cylinder head. 
It will be apparent to those skilled in the art that various modifications 
and variations can be made to the structure of the present invention 
without departing from the scope or spirit of the invention. In view of 
the foregoing, it is intended that the present invention cover 
modifications and variations of this invention provided they fall within 
the scope of the following claims and their equivalents.