Information
-
Patent Grant
-
6526932
-
Patent Number
6,526,932
-
Date Filed
Wednesday, June 6, 200123 years ago
-
Date Issued
Tuesday, March 4, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Eschweiler & Associates, LLC
-
CPC
-
US Classifications
Field of Search
-
International Classifications
-
Abstract
An internal combustion engine includes a combination intake and exhaust valve assembly. The combination intake and exhaust valve assembly includes an intake valve and an exhaust valve which are disposed in a coaxial relationship. The intake valve has an annular rim portion which is movable into and out of engagement with an intake valve seat. The exhaust valve has a head end portion with an annular rim which is movable into and out of engagement with a valve seat disposed on the intake valve. When the intake valve is operated from a closed position to an open position, the intake and exhaust valves move together. A pair of rocker arms may be used to move the intake valve from its closed position to its open position. A single rocker arm may be used to move the exhaust valve from its closed position to its open position.
Description
BACKGROUND OF THE INVENTION
The present invention relates to intake and exhaust valves for an internal combustion engine.
Known internal combustion engines of either the diesel or the spark ignition type include one or more intake valves which control the flow of an air fuel mixture to a combustion chamber of the engine. One or more exhaust valves are utilized to control the flow of exhaust gases from the combustion chamber of the engine. The power of the engine has previously been limited by the amount of the air which can be drawn into the engine during an intake stroke. If the size of the intake valve is increased, the amount of the air which can be drawn into the combustion chamber is increased. Because exhaust gases are pumped out of the engine by the movement of the piston in the cylinder, the size of the exhaust valve is usually not a limiting factor in the power which can be created by an engine.
In order to increase the amount of the air which is drawn into the engine during an intake stroke, internal combustion engines have been designed with two intake valves for each cylinder chamber. Although the use of two intake valves increases the amount of the air which can be drawn into the combustion chamber, the overall size of the two intake valves is limited by the cylinder head space required for the two intake valve openings and by the cylinder head space required for one or more exhaust valve openings. Of course, the use of two intake valves increases the number of components required in an engine and the cost of the engine.
SUMMARY OF THE INVENTION
The present invention relates to a new and improved is combination intake and exhaust valve assembly which is used in an internal combustion engine. The combination intake and exhaust valve assembly includes an intake valve and an exhaust valve which are disposed in a coaxial relationship. A valve seat for a head end portion of the intake valve is disposed on the cylinder head. A valve seat for the exhaust valve is disposed on the intake valve.
When the intake valve is operated from a closed condition to an open condition, the intake and exhaust valves may be moved together. However, the exhaust valve remains in a closed condition. If desired, the exhaust valve could be moved toward the closed condition as the intake valve moves toward the open condition. The intake valve is subsequently moved from the open condition to the closed condition while the exhaust valve remains in a closed condition and moves with the intake valve. If desired, the exhaust valve could be moved toward the open condition as the intake valve moves toward the closed condition.
After an air fuel mixture has been burned in the combustion chamber, the exhaust valve is moved to the open condition. As the exhaust valve begins to move toward the open condition, a head end portion of the exhaust valve moves away from a valve seat disposed on the intake valve. Guides for movement of the exhaust valve relative to the intake valve may be mounted on the intake valve.
The present invention includes a plurality of features which may be used separately or in combination with each other. Combinations of features which are different than the combinations described herein may be used.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other features of the present invention will become more apparent upon a consideration of the following description taken in connection with the accompanying drawings wherein:
FIG. 1
is a fragmentary sectional view schematically illustrating the relationship of a combination intake and exhaust valve assembly to a cylinder head of an engine;
FIG. 2
is an enlarged fragmentary view of a portion of FIG.
1
and schematically illustrating the relationship of a head end portion of an open intake valve to a valve seat disposed on the cylinder head of the engine and the relationship of a head end portion of a closed exhaust valve to a valve seat disposed on the intake valve;
FIG. 3
is an enlarged fragmentary sectional view of a portion of FIG.
1
and illustrating the relationship of return springs to stem portions of the intake and exhaust valves;
FIG. 4
is a schematic top plan view illustrating the relationship of a camshaft to rocker arms in the engine of
FIG. 1
;
FIG. 5
is a top plan view, generally similar to
FIG. 4
, illustrating the relationship of a second embodiment of the camshaft and rocker arms in an engine, similar to the engine of
FIG. 1
; and
FIG. 6
is schematic diagram illustrating a side view of an alternative arrangement for a valve operating assembly according to an aspect of the present invention.
DESCRIPTION OF SPECIFIC PREFERRED EMBODIMENTS OF THE INVENTION
An engine
10
is illustrated schematically in FIG.
1
. The engine
10
is of the spark ignition type and therefore has a spark plug
12
to ignite an air fuel mixture. However, the engine
10
could be of the diesel type if desired. If the engine
10
was of the diesel type, the spark plug
12
would be omitted.
The engine
10
includes a cylinder block
14
and a cylinder head
16
which is fixedly secured to the cylinder block. The cylinder block
14
defines a cylinder
20
in which a cylindrical piston
22
reciprocates during operation of the engine. The cylinder head
16
is provided with intake ports
24
through which an air fuel mixture, indicated schematically as
26
in
FIG. 1
, enters the cylinder head
16
. Of course, if fuel is injected directly into the cylinder
20
, only air would be drawn in through the intake ports
24
. In addition, the cylinder head
16
includes an exhaust port
30
through which exhaust gases, indicated schematically by arrows
32
in
FIG. 1
, are discharged from the cylinder head
16
.
In accordance with one of the features of the present invention, a combination intake and exhaust valve assembly
40
is provided in the cylinder head
16
. The combination intake and exhaust valve assembly
40
includes an intake valve
44
and an exhaust valve
46
. The intake valve
44
controls a flow of fluid which may be the air fuel mixture
26
or, in some engines, may be just air, through the intake port
24
into a combustion chamber
50
formed between the piston
22
, cylinder head
16
and the upper end portion of the cylinder block
14
. The exhaust valve
46
controls the flow of fluid, which is exhaust gases
32
, from the combustion chamber
50
through the exhaust port
30
.
The intake valve
44
and exhaust valve
46
are disposed in a coaxial relationship. Thus, the intake valve
44
and exhaust valve
46
have a common central axis
54
(FIGS.
1
and
2
). The intake valve
44
is axially movable along the axis
54
between a closed condition blocking the flow of gas through an inlet port
58
and an open condition, illustrated in
FIG. 2
, enabling the air fuel mixture
26
to flow through the inlet port. Similarly, the exhaust valve
46
is operable between a closed condition blocking the flow of gas through an outlet port
62
in the manner illustrated in FIG.
2
and an open condition enabling exhaust gases to flow through the outlet port
62
.
The intake valve
44
includes a circular head end portion
66
and a cylindrical stem portion
68
(FIG.
2
). The head end portion
66
and stem portion
68
have a common central axis
54
and are fixedly connected with each other. However, if desired, the central axis of the stem potion
68
could be offset from the central axis of the head end portion
66
.
The head end portion
66
(
FIG. 2
) of the intake valve
44
includes an annular rim portion
70
which is engagable with an annular valve seat
72
. In the illustrated embodiment of the invention, the valve seat
72
is integrally formed as one piece with the cylinder head
16
. However, if desired, the valve seat
72
could be formed by an annular ring which is mounted on the cylinder head
16
.
When the intake valve
44
is in the closed condition, the rim portion
70
on the head end portion
66
of the intake valve is disposed in sealing engagement with the valve seat
72
disposed on the cylinder head
66
. When the intake valve
44
is in the open condition, illustrated in
FIG. 2
, the rim portion
70
on the head end portion
66
of the intake valve is spaced from the valve seat
72
. The intake valve
44
reciprocates between the open and closed conditions along the axis
54
.
In accordance with one of the features of the invention, the annular rim portion
70
(
FIG. 2
) of the intake valve
44
has a relatively large diameter. This results in a relatively large annular opening
78
being formed between the rim portion
70
of the intake valve
44
and the valve seat
72
. The relatively large area of the opening
78
is achieved even though the intake valve
44
moves through a relatively small distance along the axis
54
.
The large area of the annular opening
78
facilitates flow of the air fuel mixture
26
into the combustion chamber
50
when the intake valve
44
is in the open condition of FIG.
2
. Thus, even though the annular opening
78
has a relatively short vertical (as viewed in
FIG. 2
) extent, the large diameter of the opening results in the opening having a relatively large area. The relatively large area of the opening
78
promotes efficient operation of the engine
10
since air or an air fuel mixture
26
can easily be drawn into the combustion chamber
50
by suction created during downward (as viewed in
FIG. 2
) movement of the piston
22
with the intake valve
44
in the open condition.
The exhaust valve
46
(
FIG. 2
) has a circular head end portion
84
and a cylindrical stem portion
86
. The cylindrical stem portion
86
extends along the center of the stem portion
68
of the intake valve
44
. In the illustrated embodiment of the invention, the exhaust valve stem portion
86
has a central axis which is coincident with the central axis
54
of the combination intake and exhaust valve assembly
40
. However, it is contemplated that the coincident central axes of the intake valve stem portion
68
and exhaust valve stem portion
86
could be offset from the central axis of the head end portion
66
of the intake valve
44
if desired.
During movement of the intake valve
44
between the open and closed conditions, the exhaust valve
46
remains in the closed condition illustrated in FIG.
2
. The closed exhaust valve
46
moves with the intake valve
44
as the intake valve moves between the open and closed conditions.
When the intake valve
44
is in the closed condition, the exhaust valve
46
is axially moved relative to the intake valve between open and closed conditions. Thus, the exhaust valve
46
moves with the intake valve
44
during operation of the intake valve between the open and closed conditions while the exhaust valve remains in the closed condition illustrated in FIG.
2
. However, during movement of the exhaust valve
46
between its open and closed conditions, the intake valve
44
remains stationary in the closed condition. It should be understood that there may be some overlapping of operation of the intake valve
44
and exhaust valve
46
between their open and closed conditions so that, as the intake valve
44
is opening, the exhaust valve
46
may not be completely closed.
The head end portion
84
of the exhaust valve
46
includes an annular rim portion
92
which is coaxial with the annular rim portion
70
of the intake valve
44
. The rim portion
92
of the exhaust valve
46
is engagable with an annular valve seat
96
formed on the head end portion
66
of the intake valve
44
. Although the intake valve rim portion
70
, intake valve seat
72
, exhaust valve rim portion
92
and exhaust valve seat
96
are all disposed in a coaxial relationship, it is contemplated that they could be disposed in a different relationship if desired.
When the exhaust valve
46
is in the closed condition of
FIG. 2
, the annular rim portion
92
on the circular head end portion
84
of the exhaust valve
46
sealingly engages the annular valve seat
96
on the intake valve
44
to block the flow of gas from the combustion chamber
50
. When the exhaust valve
46
is in the open condition, the rim portion
92
of the exhaust valve is spaced from the valve seat
96
. When the exhaust valve
46
is in the open condition, exhaust gases can flow from the combustion chamber
50
through an annular opening formed between the head end portion
84
of the exhaust valve
46
and the head end portion
66
of the intake valve
44
.
In accordance with another feature of the present invention, the exhaust gases are conducted through cavities and/or passages formed in the intake valve
44
. The intake valve
44
includes a cylindrical recess
102
formed in the head end portion
66
and the stem portion
68
of the intake valve
44
. The recess
102
is open to the combustion chamber
50
through the annular space between the exhaust valve seat
96
and the rim portion
92
of the exhaust valve
46
when the exhaust valve is in the open condition. The recess
102
has a central axis which is coincident with the axis
54
.
When the exhaust valve
46
is in the open condition, exhaust gases
32
flow from the recess
102
through a plurality of cylindrical passages
104
(
FIG. 2
) formed in the stem portion
68
of the intake valve
44
. The passages
104
extend parallel to the axis
54
and are disposed in a circular array about the axis
54
. Although only two passages
104
are shown in
FIG. 2
, it should be understood that there may be any suitable number of passages. For example, there may be six passages
104
formed in the stem portion
68
of the intake valve
44
.
The exhaust gases flow from the passages
104
into a relatively large cylindrical recess
108
formed in the stem portion
68
of the intake valve
44
. The cylindrical recess
108
has a central axis which is coincident with the axis
54
. The cylindrical recess
108
has an inside diameter which is greater than the outside diameter of the circular array of passages
104
. The inside diameter of the cylindrical recess
108
is approximately the same as the inside diameter of the recess
102
. The cylindrical recess
108
has an axial extent which is substantially greater than the axial extent of the recess
102
.
The exhaust gases flow from the recess
108
through a, plurality of circular openings
110
into a cylindrical head exhaust chamber
112
through which the stem portion
68
of the intake valve
44
extends. The circular openings
110
have coincident central axes extending perpendicular to the axis
54
. The combined cross sectional area of the openings
110
can be greater than the cross sectional area of the recess
108
. The exhaust gases flow from the exhaust chamber
112
through an exhaust port
30
.
The exhaust valve stem portion
86
extends through the recesses
102
and
108
formed in the stem portion
68
of
1
the intake valve
44
. Cylindrical valve guides
122
and
124
(
FIG. 2
) guide movement of the exhaust valve
46
between the open and closed conditions. The exhaust valve guides
122
and
124
are mounted on and are coaxial with the stem portion
68
of the intake valve
44
. The valve guides
122
and
124
engage the cylindrical stem portion
86
of the exhaust valve
46
to guide movement of the exhaust valve.
Similarly, cylindrical valve guides
128
and
130
are mounted on the cylinder head
16
to guide movement of intake valve
44
. The intake valve guides
128
and
130
are coaxial with the exhaust valve guides
122
and
124
and the exhaust valve stem portion
68
. If desired, the exhaust valve guides
128
and
130
could be omitted and surfaces on the cylinder head
16
could be utilized to guide movement of the intake valve
44
. Similarly, the exhaust valve guides
122
and
124
could be omitted and surfaces on the stem portion
68
of the intake valve
44
could be utilized to guide movement of the exhaust valve
46
.
Valve Actuation Apparatus
A valve actuation apparatus
140
(
FIGS. 3 and 4
) effects operation of the intake valve
44
and exhaust valve
46
between their open and closed conditions. The valve actuation apparatus
140
includes a valve closing spring system
144
(
FIG. 3
) which is effective to urge the intake valve
44
and the exhaust valve
46
to their closed conditions. In addition, the valve actuation apparatus
140
includes a valve operating assembly
148
(
FIG. 4
) which effects operation of the intake valve
44
and exhaust valve
46
from their closed conditions to their open conditions against the influence of the valve closing spring system
144
(FIG.
3
).
The valve closing spring system
144
includes a helical coil intake valve spring
152
which engages a cylindrical spring retainer
154
(FIG.
3
). The spring retainer
154
is connected with an upper end portion of the intake valve
44
. Thus, the spring retainer
154
is connected to the stem portion
68
of the intake valve
44
by circular clips
158
and
160
. The clips
158
and
160
extend into annular grooves which extend around the stem portion
68
of the intake valve
44
. The spring
152
and spring retainer-
154
are disposed in a coaxial relationship with the stem portion
68
of the intake valve
44
.
The spring
152
is maintained in a compressed condition by the spring retainer
154
. Therefore, there is always a biasing force applied against the spring retainer
154
urging the intake valve
44
toward is closed condition. The spring retainer
154
slidably engages a cylindrical guide surface
164
formed on the cylinder head
16
.
When the intake valve
44
is operated to the open condition, the spring retainer
154
is forced downward along the guide surface
164
to the position illustrated in FIG.
3
. Downward movement of the spring retainer
154
, to the position illustrated in
FIG. 3
, compresses the spring
152
as the intake valve
44
is operated from its closed condition to its open condition. When the intake valve
44
is to be operated from the open condition back to the closed condition, the intake valve is released and the spring
152
moves the spring retainer
154
and valve stem
68
upward (as viewed in
FIG. 3
) to close the intake valve. The spring
152
and spring retainer
154
are effective to apply force against the closed intake valve
44
to firmly seal the intake valve against the valve seat
72
(FIG.
2
).
The valve closing spring system
144
also includes a helical coil exhaust valve spring
170
(FIG.
3
). The exhaust valve spring
170
is constantly maintained in a compressed condition by engagement with a spring retainer
172
. The spring retainer
172
has a generally rectangular configuration and extends through generally rectangular openings
174
and
176
formed in the stem portion
68
of the intake valve
44
. The spring retainer
172
is connected with the stem portion
86
of the exhaust valve
46
by circular clips
180
and
182
.
The exhaust valve spring
170
is effective to constantly urge the exhaust valve
46
toward the closed condition of FIG.
2
. The exhaust valve spring
170
is circumscribed by and is coaxial with the intake valve spring
152
and the stem portion
86
of the exhaust valve
46
.
When the exhaust valve
46
is to be operated from the closed condition to the open condition, the exhaust valve stem portion
86
is moved downward (as viewed in
FIG. 3
) relative to the intake valve stem portion
68
. A cylindrical guide wall
186
is slidably engaged by the spring retainer
172
to guide movement of the spring retainer. As the spring retainer
172
moves downward (as viewed in
FIG. 3
) the exhaust valve spring
170
is further compressed.
When the exhaust
46
is to be operated from the open condition to the closed condition, the exhaust valve is released. The spring retainer
172
is then moved upward along the cylindrical guide wall
186
by the spring
170
. This moves the exhaust valve
46
upward to close the exhaust valve. The spring
170
and spring retainer
172
are effective to apply force against the closed exhaust valve
46
to firmly seal the exhaust valve against the valve seat
96
on the intake valve
44
(FIG.
2
).
The valve operating assembly
148
(
FIG. 4
) is effective to move the intake valve
44
and exhaust valve
46
against the influence of the intake valve spring
152
and the exhaust valve spring
170
(FIG.
3
). The valve operating assembly
148
(
FIG. 4
) includes a rotatable camshaft
190
. The camshaft
190
extends perpendicular to and is offset to one side of the central axis
54
of the intake and exhaust valves
44
and
46
(FIGS.
1
and
4
). The camshaft
190
has a pair of intake valve actuation control lobes
194
and
196
(
FIG. 4
) which are fixedly connected with the camshaft. In addition, the camshaft
190
includes an exhaust valve actuation control lobe
198
which is also fixedly connected with the camshaft.
A single, generally U-shaped intake valve actuator
202
(
FIG. 4
) has a pair of generally parallel rocker arms
206
and
208
(FIGS.
3
and
4
). The rocker arm
206
is disposed in engagement with the lobe
194
on the camshaft
190
and with an upstanding (as viewed in
FIG. 3
) end section
210
of the stem portion
68
of the intake valve
44
. The rocker arm
208
engages the lobe
196
on the camshaft
190
and an upstanding end section
212
of the stem portion
68
of the intake valve
44
.
The two parallel rocker arms
206
and
208
of the intake valve actuator
202
(
FIG. 4
) have coaxial mounting sections
216
and
218
which are rotatably supported on a rocker shaft
220
. The rocker shaft
220
extends parallel to the camshaft
190
. The rocker arms
206
and
208
are interconnected by an arcuate connector portion
222
of the intake valve actuator
202
.
The connector portion
222
of the valve actuator is urged toward the camshaft
190
by a strong helical coil actuator biasing spring (not shown). The actuator biasing spring extends between the cylinder head
16
and the connector portion
222
of the intake valve actuator
202
. The actuator biasing spring engages an underneath side of the valve actuator
202
opposite from the camshaft
190
. A fastener
224
on the connector section
222
of the intake valve actuator
202
engages an actuator spring retainer.
The spring force applied against the connector section
222
of the intake valve actuator
202
by the actuator biasing spring firmly presses the arms
206
and
208
of the intake valve actuator against the valve actuation control lobes
194
and
196
on the camshaft
190
. The actuator biasing spring is substantially stronger than and easily overcomes the combined effect of the intake valve spring
152
and exhaust valve spring
170
. Therefore, whenever relatively small radius dwell portions of the lobes
194
and
196
on the camshaft
190
are in engagement with the rocker arms
206
and
208
, the actuator biasing spring is effective to pivot the connector portion
222
about the rocker shaft
220
to open the intake valve
44
.
An exhaust valve actuator
230
(
FIG. 4
) cooperates with the camshaft
190
to operate the exhaust valve
46
from the closed condition to the open condition against the influence of the exhaust valve spring
170
(FIG.
3
). The exhaust valve actuator
230
includes a single rocker arm
232
which is disposed between and extends parallel to the rocker arms
206
and
208
of the intake valve actuator
202
. The arm
232
of the exhaust valve actuator
230
has a mounting section
236
which is rotatably mounted on the rocker shaft
220
.
The exhaust valve rocker arm
232
is rotatable about the rocker shaft
220
independently of rotation of the rocker arms
206
and
208
on the intake valve actuator
202
about the rocker shaft
220
. Thus, the intake valve rocker arms
206
and
208
may be rotating in one direction about the rocker shaft
220
while the exhaust valve rocker arm
232
is rotating in the opposite direction about the rocker shaft.
A relatively strong, helical coil, actuator biasing spring (not shown) is provided at one end, that is the left end as viewed in
FIG. 4
, of the rocker arm
232
to bias the rocker arm
232
into engagement with the exhaust valve control lobe
198
on the camshaft
190
. A suitable spring retainer (not shown) is connected with a fastener
240
to position the exhaust valve actuator biasing spring between the cylinder head
16
and the rocker arm
232
. The exhaust valve actuator biasing spring is substantially stronger than and easily overcomes the exhaust valve spring
170
.
Although one specific valve operating assembly
148
has been illustrated in
FIG. 4
, it is contemplated that a different valve operating assembly could be utilized if desired.
Operation
During operation of the engine
10
, the camshaft
190
(
FIG. 4
) is continuously rotated to enable movement of the intake valve actuator
202
and exhaust valve actuator
230
. The intake and exhaust valves
44
and
46
(
FIG. 3
) move between their open and closed conditions in a timed relationship with movement of the piston
22
(
FIG. 1
) in the cylinder block
14
. When the intake valve
44
is in a closed condition, the rim portion
70
(
FIG. 2
) of the intake valve
44
is disposed in sealing engagement with the valve seat
72
. When the exhaust valve
46
is closed, the rim portion
92
of the exhaust valve is disposed in sealing engagement with the valve seat
96
.
When the intake valve
44
is to be operated from the closed condition to an open condition, the camshaft
190
(
FIG. 4
) rotates so as to engage the relatively small radius dwell portions of the intake valve actuation control lobes
194
and
196
with the intake valve rocker arms
206
and
208
. This enables the actuator biasing spring for the intake valve actuator
202
to pivot the intake valve actuator about the rockshaft
220
. As this occurs, the right (as viewed in
FIG. 4
) end portions of the intake valve rocker arms
206
and
208
move downward (as viewed in FIG.
3
). Since the actuator biasing spring for the intake valve actuator
202
is substantially stronger than the combined intake valve spring
152
and exhaust valve spring
170
, the intake valve
44
and exhaust valve
46
are easily moved downward (as viewed in
FIG. 3
) by the intake valve rocker arms
206
and
208
. The exhaust valve
46
remains in the closed condition as it moves downward with the intake valve
44
.
Downward movement of the intake valve rocker arms
206
and
208
applies force to the end sections
210
and
212
of stem portion
68
of the intake valve
44
. This force moves the head end portion
66
(
FIG. 2
) of the intake valve
44
from its closed condition to its open condition against the influence of the intake valve spring
152
(FIG.
3
). As the intake valve
44
moves from the closed condition to the open condition, the exhaust valve
46
moves with the intake valve against the influence of the exhaust valve spring
170
.
When the intake valve
44
is in the open condition illustrated in
FIG. 2
, there is a relatively large annular opening
78
formed between the head end portion
66
of the intake valve
44
and the valve seat
72
. Although the opening
78
has a relatively small vertical (as viewed in
FIG. 2
) extent, the annular opening
78
has a relatively large circumference. The large circumference of the annular opening
78
enables the air fuel mixture
26
to freely move into the combustion chamber
50
as the piston
22
moves downward (as viewed in FIG.
2
).
The exhaust valve
46
moves with the intake valve
44
as the intake valve moves from its closed condition to its open condition. The exhaust valve
46
may be continuously maintained in its closed condition by the exhaust valve spring
170
(
FIG. 3
) during movement of the intake valve
44
from the closed condition to the open condition. This results in the exhaust valve
46
being stationary relative to the intake valve
44
. Therefore, the stem portion
86
of the exhaust valve
46
moves away from the arm.
232
(
FIG. 4
) of the exhaust valve actuator
230
, in the manner illustrated schematically in FIG.
3
. Alternatively, the exhaust valve
46
may move toward its closed condition as the intake valve
44
is moving toward its open condition. This would result in the exhaust valve
46
moving upward (as viewed in
FIG. 2
) relative to the intake valve
44
, as the intake valve moves downward.
When the intake valve
44
is to be returned to its closed position, rotation of the camshaft
190
moves the small radius dwell portions of the intake valve actuator control lobes
194
and
196
out of engagement with the intake valve rocker arms
206
and
208
. The large radius nose portions of the intake valve actuator control lobes
194
and
196
move into engagement with the intake valve rocker arms
206
and
208
. As this occurs, the rocker arms
206
and
208
move upward (as viewed in FIG.
3
). The intake valve
44
then moves upward (as viewed in
FIG. 3
) under the influence of the intake valve spring
152
to again move the rim portion
70
(
FIG. 2
) of the intake valve
44
into sealing engagement with the valve seat
72
.
The exhaust valve
46
is subsequently operated from the closed condition illustrated in
FIG. 2
to its open condition. As the exhaust valve
46
moves from the closed condition to the open condition, the intake valve
44
remains stationary in sealing engagement with the valve seat
72
. As the exhaust valve
46
moves to its open condition, it moves downward (as viewed in
FIG. 2
) relative to the intake valve
44
and cylinder head
16
. This downward movement occurs against the influence of the exhaust valve spring
170
(FIG.
3
).
To effect downward movement (as viewed in
FIGS. 2 and 3
) of the exhaust valve
46
against the influence of the exhaust valve spring
170
(FIG.
3
), the exhaust valve actuator control lobe
198
(
FIG. 4
) on the camshaft
190
releases the exhaust valve rocker arm
232
for pivotal movement under the influence of the relatively strong actuator biasing spring connected with the fastener
240
. This results in the exhaust valve rocker arm
232
being pivoted about the rockshaft
220
by the actuator biasing spring to move the exhaust valve rocker arm
230
downward (as viewed in FIG.
3
). This applies force against the stem portion
86
of the exhaust valve
46
to move the exhaust valve relative to the intake valve
44
.
As the exhaust valve
46
moves relative to the intake valve
44
, the rim portion
92
(
FIG. 2
) on the head end portion
84
of the exhaust valve
46
moves away from the valve seat
96
on the intake valve
44
. This results in the formation of an annular opening through which exhaust gases
32
move from the combustion chamber
50
into the recess
102
in the intake valve stem
68
. The exhaust gases flow from the recess
102
through the passages
104
into the recess
108
in the valve stem portion
68
of the intake valve
44
. The exhaust gases then flow through the openings
110
in the intake valve
44
and from the cylinder head
16
through the exhaust port
30
.
When the exhaust valve
46
is to be closed, rotation of the camshaft
190
results in the exhaust valve actuator cam lobe
198
pivoting the exhaust valve rocker arm
232
to release the exhaust valve
46
for upward movement under the influence of the exhaust valve spring
170
(FIG.
3
). As this occurs, the exhaust valve
46
moves from its open condition to its closed condition.
During operation of the engine
10
, the intake valve stem portion
68
(
FIGS. 2 and 3
) and the exhaust valve stem portion
86
function as force application portions to which force is applied by the valve operating assembly
148
(FIG.
4
). The intake valve seat
96
(
FIG. 2
) on the intake valve
44
functions as a force transmitting portion to transmit force to the exhaust valve
46
. The rim portion
92
on the head end portion
84
of the exhaust valve
46
functions as a force application surface to which force is applied to the exhaust valve
46
by the intake valve
44
.
In the embodiment of the combination intake and exhaust valve assembly
40
illustrated in
FIG. 2
, the exhaust valve seat
96
on the intake valve
44
and the rim portion
92
of the intake valve
40
cooperate to perform the dual functions of blocking gas flow from the combustion chamber
50
through the intake valve stem portion
68
and transmitting force from the intake valve
44
to the exhaust valve
46
. However, if desired, surfaces separate from the exhaust valve seat
96
and rim portion
92
of the exhaust valve
46
could be utilized to transmit force to the exhaust valve
46
.
Valve Operating Assembly—Second Embodiment
In the embodiment of the invention illustrated in
FIG. 4
, the intake valve
44
and exhaust valve
46
are operated between their open and closed conditions under the influence of spring force applied against the intake valve rocker arms
206
and
208
and the exhaust valve rocker arm
232
by relatively strong actuator springs. In the embodiment of the invention illustrated in
FIG. 5
, force for operating the intake and exhaust valves between their open and closed conditions is transmitted directly from the camshaft lobes to the intake and exhaust valve rocker arms. Since the embodiment of the invention illustrated in
FIG. 5
is generally similar to the embodiment of the invention illustrated in
FIG. 4
, similar numerals will be utilized to designate similar components, the suffix letter “a” being associated with the numerals of
FIG. 5
to avoid confusion.
A valve operating assembly
148
a
(
FIG. 5
) is utilized to operate a combination intake and exhaust valve assembly
40
a
having the same construction and mode of operation as the combination intake and exhaust valve assembly
40
of
FIGS. 1-3
. The combination intake and exhaust valve assembly
40
a
includes an intake valve
44
a
and an exhaust valve
46
a
. A camshaft
190
a
has an intake valve actuation control lobe
194
a
which actuates an intake valve actuator
202
a
. In addition, the camshaft
190
a
has an exhaust valve actuation control lobe
198
a
which actuates an exhaust valve actuator
230
a.
The intake valve actuator
202
a
is pivotally mounted on a pair of supports
250
and
252
connected with a cylinder head
16
a
. The intake valve actuator
202
a
includes a pair of parallel rocker arms
206
a
and
208
a
which engage upper end portions
210
a
and
212
a
of a stem portion
68
a
of the intake valve
44
a
. A rocker arm
254
of the intake valve actuator
202
a
is moved by the cam lobe
194
a
during rotation of the camshaft
190
a.
The exhaust valve actuator
230
a
includes a support shaft
258
which is rotatably mounted at opposite ends on the intake valve actuator
202
a
. The support shaft
258
is fixedly connected with a rocker arm
232
a
and a rocker arm
262
. The rocker arm
262
is moved by the exhaust valve actuator lobe
198
a
on the camshaft
190
a
during rotation of the camshaft.
Valve Operating Assembly—Third Embodiment
A side view of an alternative arrangement of an operating assembly
148
b
is shown in FIG.
6
. As in
FIG. 5
, similar numerals are utilized to designate similar components, the suffix letter “b” being associated with the reference numerals in FIG.
6
. The assembly
148
b
is utilized to operate a combination intake and exhaust valve assembly
40
b
having the same construction and mode of operation as the combination intake and exhaust valve assembly
40
depicted in
FIGS. 1-3
.
An exhaust valve rocker arm
232
b
is shown in operative association with an exhaust valve
46
b
. The exhaust valve
46
b
is coaxially arranged within an intake valve
44
b
. Rocker arm(s) for the intake valve
44
b
are not shown. The exhaust valve rocker arm
232
b
is operatively connected to a mounting shaft
300
. In particular, the mounting shaft
300
passes through an oval shaped aperture
304
formed within the exhaust valve rocker arm
232
b
. The mounting shaft
300
is fixedly associated with a member
310
connected to the engine head
314
. The oval shaped aperture
304
inhibits-horizontal, but allows vertical movement of the exhaust valve rocker arm
232
b
in a direction parallel to a central axis
54
b
of the exhaust
46
b
and intake
44
b
valves.
A portion of the exhaust valve rocker arm
232
b
situated opposite the valves
44
b
,
46
b
is supported by a spacer
320
. The spacer
320
is juxtaposed between the exhaust valve rocker arm
232
b
and the engine head
314
. One end
322
of the spacer
320
is connected to the engine head
314
while the other end
324
of the spacer
320
is secured to the exhaust valve rocker arm
232
b
by an adjustable fastener
330
. The adjustable fastener
330
can be utilized to regulate the degree of contact between a surface
340
of the exhaust valve rocker arm
232
b
and a lobe
194
b
of a camshaft
190
b
. Also opposite the valves
44
b
,
46
b
, a spring
360
is interposed between the engine head
314
and the exhaust valve rocker arm
232
b
. The spring
360
is maintained in a compressed condition by the exhaust valve rocker arm
232
b
and, therefore, continually applies an upward biasing force against the exhaust valve rocker arm
232
b
. This biasing force serves to keep the surface
340
of the exhaust valve rocker arm
232
b
in contact with the lobe
194
b
of the camshaft
190
b.
The spring
360
is designed such that its upward biasing force can be overcome by a downward force applied to the exhaust valve rocker arm
232
b
by a large radius dwell portion
354
of the lobe
194
b
on the camshaft
190
b
. In this manner, when the camshaft
190
b
rotates and the large radius dwell portion
354
of the lobe
194
b
contacts the surface
340
of the exhaust valve rocker arm
232
b
, the exhaust valve rocker arm is forced downward in a direction parallel to the central axis
54
b
of the valves
44
b
,
46
b
. As the camshaft
190
b
rotates further and a small radius dwell portion of the lobe
194
b
comes into contact with the surface
340
of the exhaust valve rocker arm
232
b
, the biasing force of the spring
360
forces the exhaust valve rocker arm
232
b
back up.
Depending upon the arrangement of the exhaust valve
46
b
within the intake valve
44
b
and more particularly the timed relationship between the opened and closed conditions of the valves, when the exhaust valve rocker arm
232
b
is forced downward, it may come into contact with and act upon the exhaust valve
46
b
causing the exhaust valve
46
b
to move to its open condition. Similarly, when the exhaust valve rocker arm
232
b
is forced back up, the exhaust valve
46
b
may return to its closed condition, again depending upon the orientation of the exhaust
46
b
and intake
44
b
valves.
It is to be appreciated, however, that depending upon factors, such as the timed relationships between the opened or closed conditions of the valves
44
b
,
46
b
, movement of the exhaust valve rocker arm
232
b
may or may not affect the condition of the exhaust valve
46
b
. If, for instance, the exhaust
46
b
and intake
44
b
valves move together and the valves are moved downward by an intake valve rocker arm (not shown), the exhaust valve rocker arm
232
b
may or may not come into contact with and have any affect upon the condition of the exhaust valve
46
b
when the exhaust valve rocker arm
232
b
is forced downward by a large radius dwell portion
354
of lobe
194
b
. In this manner, the movement and condition of the exhaust valve
46
b
is somewhat independent of the exhaust valve rocker arm
232
b
. As such, depending upon what is desired, the arrangement can be configured to move the valves
44
b
,
46
b
between their opened and closed conditions in any suitable timed relationships.
While this arrangement has been discussed with respect to an exhaust valve
46
b
and an exhaust valve rocker arm
232
b
, it is to be appreciated that the same arrangement may be applied to other valves and valve rocker arms, such as an intake valve and intake valve rocker arms.
CONCLUSION
The present invention relates to a new and improved combination intake and exhaust valve assembly
40
which is used in an internal combustion engine
10
. The combination intake and exhaust valve assembly
40
includes an intake valve
44
and an exhaust valve
46
which are disposed in a coaxial relationship. A valve seat
72
for a head end portion of the intake valve
44
is disposed on the cylinder head
16
. A valve seat
96
for the exhaust valve
46
is disposed on the intake valve
44
.
When the intake valve
44
is operated from a closed condition to an open condition, the intake and exhaust valves
44
and
46
may be moved together. However, the exhaust valve
46
remains in a closed condition. If desired, the exhaust valve
46
could be moved toward the closed condition as the intake valve
44
moves toward the open condition. The intake valve is subsequently moved from the open condition to the closed condition while the exhaust valve
46
remains in a closed condition and moves with the intake valve. If desired, the exhaust valve
46
could be moved toward the open condition as the intake valve
44
moves toward the closed condition.
After an air fuel mixture has been burned in the combustion chamber
50
, the exhaust valve
46
is moved to the open condition. As the exhaust valve
46
begins to move away from the closed condition, a head end portion
84
of the exhaust valve moves away from a valve seat
96
disposed on the intake valve. Guides for movement of the exhaust valve relative to the intake valve may be mounted on the intake valve.
The present invention includes a plurality of features which may be used separately or in combination with each other. Combinations of features which are different than the combinations described herein may be used. For example, the combination intake and exhaust valve assembly
40
may be actuated by valve operating assemblies having constructions which are different than the constructions of the valve operating assemblies
148
,
148
a
and
148
b
. As another example, the valve
44
could be used to control gas flow from the combustion chamber
50
and the valve
46
could be used to control gas flow to the combustion chamber.
Claims
- 1. A combination intake and exhaust valve assembly for use in controlling flow to and from a combustion chamber of an internal combustion engine, said valve assembly comprising an intake valve having a head portion that includes an annular rim portion movable into and out of engagement with an annular intake valve seat defined by a portion of a cylinder head of the internal combustion engine that at least partially overlaps said annular rim portion of said intake valve to control flow into the combustion chamber of the internal combustion engine during operation of the internal combustion engine and an annular exhaust valve seat circumscribed by said annular rim portion and at least partially defining an exhaust valve seat, and an exhaust valve having an annular rim portion movable into and out of engagement with said exhaust valve seat in said intake valve to control flow from the combustion chamber of the internal combustion engine during operation of the internal combustion engine.
- 2. A valve assembly as set forth in claim 1 wherein said intake valve includes a head portion and a stem portion which is connected with said head portion, said annular rim portion of said intake valve and said annular exhaust valve seat being disposed on said head portion of said intake valve, said exhaust valve includes a head portion and a stem portion which is connected with said head portion of said exhaust valve, said annular rim portion of said exhaust valve being disposed on said head portion of said exhaust valve.
- 3. A valve assembly as set forth in claim 2 wherein said stem portions of said intake and exhaust valves are disposed in a coaxial relationship.
- 4. A valve assembly as set forth in claim 3 wherein said stem portion of said exhaust valve is at least partially enclosed by said stem portion of said intake valve.
- 5. A valve assembly as set forth in claim 3 wherein said intake valve includes an exhaust valve guide disposed in said stem portion of said intake valve, said stem portion of said exhaust valve extends through said exhaust valve guide, said exhaust valve guide has a guide surface which engages said stem portion of said exhaust valve to guide movement of said exhaust valve relative to said intake valve during operation of the internal combustion engine.
- 6. A valve assembly as set forth in claim 2 wherein said stem portion of said intake valve includes a passage through which flow is conducted from said exhaust valve seat during operation of the internal combustion engine.
- 7. A valve assembly as set forth in claim 6 further including an exhaust valve guide disposed in the passage through which flow is conducted from said exhaust valve seat during operation of the internal combustion engine, said exhaust valve guide having surface means for guiding movement of said exhaust valve relative to said intake valve.
- 8. A valve assembly as set forth in claim 2 further including an intake valve spring extending around said stem portion of said intake valve and connected with said stem portion of said intake valve to urge said rim portion of said intake valve toward the intake valve seat in the internal combustion engine, and an exhaust valve spring extending around said stem portion of said exhaust valve and connected with said stem portion of said exhaust valve to urge said rim portion of said exhaust valve toward said exhaust valve seat in said intake valve.
- 9. A valve assembly as set forth in claim 8 wherein said intake valve spring and said exhaust valve spring have coincident central axes which are coincident with central axes of said stem portions of said intake and exhaust valves.
- 10. A valve assembly as set forth in claim 8 wherein said intake valve spring extends around at least a portion of said exhaust valve spring.
- 11. A valve assembly as set forth in claim 2 wherein said stem portion of said intake valve includes a plurality of ports through which flow from said exhaust valve seat is conducted during operation of the internal combustion engine.
- 12. A valve assembly as set forth in claim 2 wherein said stem portion of said intake valve includes a force application surface to which force is transmitted during operation the internal combustion engine to move said intake valve during operation of the internal combustion engine, said exhaust valve seat in said intake valve being effective to transmit force applied to said force application surface to move said exhaust valve during operation of the internal combustion engine.
- 13. A combination intake and exhaust valve assembly for use in an internal combustion engine, said valve assembly comprising an intake valve having an intake valve force application portion to which force is applied to effect movement of said intake valve from a closed position blocking flow to a combustion chamber of the internal combustion engine through engagement of an annular rim portion of a head portion of said intake valve with an intake valve seat defined by a portion of a cylinder head of the internal combustion engine that at least partially overlaps said annular rim portion of said intake valve to an open position enabling flow to the combustion chamber of the internal combustion engine during operation of the internal combustion engine, and an exhaust valve having a first force application portion to which force is applied to effect movement of said exhaust valve from a closed position blocking flow from the combustion chamber of the internal combustion engine to an open position enabling flow from the combustion engine during operation of the internal combustion engine, said intake valve including a force transmitting portion which engages a second force application portion on said exhaust valve to transmit force from said intake valve to said exhaust valve and move said exhaust valve with said intake valve during movement of said intake valve from the closed position to the open position with said exhaust valve in the closed position.
- 14. A valve assembly as set forth in claim 13 wherein said force transmitting portion of said intake valve is engage by said second force application portion on said exhaust valve when said exhaust valve is in the closed position, said second force application portion on said exhaust valve being movable away from said force transmitting portion on said intake valve under the influence of force applied to said first force application portion on said exhaust valve during movement of said exhaust valve from the closed position to the open position.
- 15. A valve assembly as set forth in claim 13 further including an intake valve spring connected with said intake valve to effect movement of said intake valve from the open position to the closed position during operation of the internal combustion engine, and an exhaust valve spring connected with said exhaust valve to effect movement of said exhaust valve from the open position to the closed position during operation of the internal combustion engine, said intake and exhaust valve springs being disposed in a coaxial relationship with said intake valve spring extending around at least a portion of said exhaust valve spring.
- 16. A valve assembly as set forth in claim 13 wherein said intake valve includes a passage which is blocked when said exhaust valve is in the closed position and is open when said exhaust valve is in the open position to enable flow to be conducted from the combustion chamber through said passage when said exhaust valve is in the open position.
- 17. A valve assembly as set forth in claim 13 further including an exhaust valve guide mounted on said intake valve, said exhaust valve guide engages said exhaust valve to guide movement of said exhaust valve between the open and closed positions.
- 18. A valve assembly as set forth in claim 17 wherein said exhaust valve guide moves with said intake valve during movement of said intake valve between the open and closed positions.
- 19. A valve assembly as set forth in claim 13 wherein said intake valve includes a tubular valve stem, said exhaust valve includes a valve stem which is disposed in a passage in said tubular intake valve stem, said force application portion on said intake valve being disposed on said tubular intake valve stem, said first force application portion on said exhaust valve being disposed on said exhaust valve stem.
- 20. An internal combustion engine comprising:an engine block defining a cylinder; a cylinder head connected with said block; said cylinder head having an intake passage communicating with the cylinder for directing intake air into the cylinder, and an intake valve seat; an intake valve supported by said cylinder head for reciprocating movement, said intake valve having a head including an annular rim portion; said intake valve being movable relative to said cylinder head between a closed condition in which said annular rim portion of said intake valve head is in sealing engagement with said intake valve seat defined by a portion of said cylinder head that at least partially overlaps said annular rim portion to block fluid flow through said intake passage, and an open condition in which said intake valve head is spaced from said intake valve seat to enable fluid flow through said intake passage into said cylinder; said cylinder head having an exhaust passage communicating with the cylinder for directing exhaust fluid out of the cylinder; an exhaust valve having a head; said intake valve having an exhaust valve seat; said exhaust valve being movable relative to said cylinder head between a closed condition in which said exhaust valve head is in sealing engagement with said exhaust valve seat on said intake valve to block fluid flow through said exhaust passage, and an open condition in which said exhaust valve head is spaced apart from said exhaust valve seat on said intake valve to enable fluid flow out of said cylinder through said exhaust passage.
- 21. An engine as set forth in claim 20 wherein said intake valve is coaxial with said exhaust valve.
- 22. An engine as set forth in claim 20 wherein said exhaust valve head is disposed radially within said intake valve head.
- 23. An engine as set forth in claim 22 wherein said intake valve head has an annular configuration extending around said exhaust valve head.
- 24. An internal combustion engine comprising:an engine block defining a cylinder; a cylinder head connected with said block; said cylinder head having an intake passage communicating with the cylinder for directing intake air into the cylinder and an exhaust passage communicating with the cylinder for directing exhaust fluid out of the cylinder; an intake valve movable relative to said cylinder head between a closed condition in which an annular rim portion of a head of said intake valve engages a portion of said cylinder head that at least partially overlaps said annular rim portion and blocks fluid flow through said intake passage and an open condition to enable fluid flow through said intake passage into said cylinder; an exhaust valve movable relative to said cylinder head between a closed condition in which said exhaust valve blocks fluid flow through said exhaust passage and an open condition to enable fluid flow out of said cylinder through said exhaust passage; said intake valve and said exhaust valve being supported on said cylinder head for reciprocating movement along a common axis, said intake valve and said exhaust valve being coaxial with each other.
US Referenced Citations (14)
Foreign Referenced Citations (1)
Number |
Date |
Country |
3725049 |
Aug 1988 |
DE |