Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2001-08-31
2004-05-11
Denion, Thomas (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090390, C123S321000
Reexamination Certificate
active
06732686
ABSTRACT:
TECHNICAL FIELD
This invention relates to a valve opening mechanism which is distinct from conventional valve opening mechanisms in that it is constituted so as to be capable of opening an engine valve with suitable timing by the means of a rocker arm.
BACKGROUND ART
The compression pressure release type of engine braking, which is constituted so that it releases pressure within a combustion chamber that has been raised by the movement of pistons through the opening of an exhaust valve in the proximity of top dead center compression, and magnifies engine braking power by diminishing the energy that drives the pistons downward in an expansion stroke, is generally known.
FIGS. 1 through 3
represent examples of the conventional compression pressure release type of engine braking. In
FIG. 1
, the number
1
identifies the cylinder,
2
the combustion chamber,
3
the piston,
4
the exhaust valve, and
5
the exhaust port, respectively, and they are configured so that the base extremity is thrown upward by a push rod
6
and both exhaust values
4
are pushed downward and opened through the use of the cross head by the tip of an inclining exhaust rocker arm
7
, and exhaust gas is scavenged from the combustion chamber
2
toward the exhaust port
5
.
Then, when both exhaust values
4
are pushed downward and opened through the use of the cross head
8
by the tip of the above-mentioned exhaust rocker arm
7
, the tip of the above-mentioned exhaust rocker arm
7
pushes downward on the master piston
12
provided in the upper portion of the housing
11
, a separate slave piston
14
in the upper part of the housing
11
is driven downward by the generation of pressure in the oil line
13
which protrudes into the interior of the above-mentioned housing
11
and, through the use of an actuator pin
15
installed on one side of the cross head
8
, an exhaust valve
4
on one side is positioned so that it can be pushed downward independently by the said slave piston
14
.
Namely, through the action of the master piston
12
in a separate cylinder
1
that constitutes an exhaust stroke, a cross linkage coinciding with the stroke timing is established by the oil line
13
between the slave piston
14
of the cylinder
1
and the master piston
12
such that the slave piston
14
in the cylinder
1
which is in proximity to top dead center compression is driven, and it is designed in such a way that operating oil
18
(engine oil) is supplied through the use of a solenoid valve
16
and a control valve
17
, which constitutes a means of supplying operating oil that switches back and forth between the sustaining and release of oil pressure in the said oil line
13
.
At this point, the solenoid valve
16
effects the supply of operating oil
18
by means of a control signal
20
from a control device
19
, and the control valve
17
functions as a check valve so that oil pressure in the above-mentioned oil line
13
is sustained when the solenoid valve
16
is in a open state, and also serves to release oil pressure in the above-mentioned oil line
13
when the solenoid valve
16
is in a closed state.
Namely, it is constituted so that, with the solenoid valve
16
, the supply of operating oil
18
is effected by the plate
22
and pin
23
pushing downward on the ball
24
when the coil
21
is in energized state, and the supply of operating oil
18
is blocked by the ball
24
being pushed upward by the spring
25
when the coil is in an unenergized state, and also so that, through the use of the control valve
17
, the spool
26
is pushed upward by oil pressure when the solenoid valve
16
is in an open state and the transport of operating oil
18
is effected only in the direction of the above-mentioned oil line
13
due to a ball
27
provided inside the said spool
26
, and oil pressure is released toward the relief outlet
29
by the spool
26
being pushed downward by the spring
28
when the solenoid valve
16
is in a closed state.
FIG. 2
illustrates a design configuration for multiple cylinders exemplified in the case of a tandem 6-cylinder engine. Only Cylinder #
1
(
1
), Cylinder #
2
(
1
), and Cylinder #
3
(
1
) are depicted, and they are constituted such that the opening action of the exhaust valve
4
in proximity to top dead center compression in Cylinder #
1
(
1
) is taken by the exhaust push rod
6
of Cylinder #
3
(
1
), the opening action of the exhaust valve
4
in proximity to top dead center compression in Cylinder #
2
(
1
) is taken by the exhaust push rod
6
of Cylinder #
1
(
1
), the opening action of the exhaust valve
4
in proximity to top dead center compression in Cylinder #
3
(
1
) is taken by the exhaust push rod
6
of Cylinder #
2
(
1
). More specifically, they are arranged so that the exhaust valve
4
on one side can be opened in proximity to top dead center compression by driving the slave piston
14
of each cylinder with the use of the oil line
13
by means of the action of the master piston
12
using the exhaust rocker arm
7
(not shown in
FIG. 2
) on the basis of the exhaust push rod
6
of each cylinder.
Furthermore, as
9
in the diagram is an inlet push rod and
10
is an intake valve, it is needless to say that the said intake valve
10
is opened by means of an intake rocker arm (not shown) which is moved at an angle by the inlet push rod
9
during an intake stroke.
Therefore, as the control valve
17
functions as a check valve and closes the oil line
13
if the solenoid valve
16
is opened by a control signal
20
from the control device
19
, in the event that Cylinder #
1
(
1
), Cylinder #
2
(
1
), and Cylinder #
3
(
1
), respectively, reach proximity to the pressure top dead center with a different timing, as is indicated in Diagram
3
, the master piston
12
is pushed downward by the exhaust rocker arm
7
with an upward thrust of the exhaust push rod
6
for the purpose of opening an exhaust valve
4
in a separate cylinder during an exhaust stroke, thus creating pressure in the oil line
13
. Since the slave piston
14
of the cylinder
1
in proximity to the pressure top dead center is driven and an exhaust valve
4
on one side is opened, compressed air from the combustion chamber
2
escapes into the exhaust port
5
and the creation of capacity to push the piston
3
downward during the next expansion stroke is lost, thus making it possible to take effective advantage of the braking capacity achieved in the compression stroke.
Moreover, in
FIG. 3
(identical for FIG.
9
and
FIG. 11
, to be referenced later), the vertical axis represents lift (lifting range) and the horizontal axis represents the angle of rotation of the camshaft in Cylinder #
1
, while the “&Dgr;” figures in the diagram indicate top dead center compression in each cylinder, the curves in the solid lines indicate lift in the exhaust valve
4
in each cylinder, and the curves in the dotted lines indicate the lift in the intake valve
10
(in Cylinder #
1
, for example, a 0°~180° angle of rotation of the camshaft constitutes a explosive stroke,180°~360° an exhaust stroke, 360°~540° an intake stroke, and 540°~720° a compression stroke, while the phases are shifted with top dead center compression as the origin.)
If the solenoid valve
16
is closed by a control signal
20
from the control device
19
, oil pressure in the oil line
13
is released by the control valve
17
, and as pressure is not generated inside the oil line
13
, the slave piston
14
ceases to be driven and the exhaust valve
4
is opened by normal valve opening operation only during an exhaust stroke and no longer is opened in proximity to top dead center compression.
In implementing the use of this compression pressure release form of engine braking, especially in the case of an OHV type engine as illustrated in
FIG. 1
, the actuator pin
15
is through mounted on the side of the cross head
8
, facing in a vertical direction, and is configured in such a way that only an exhaust valve
4
on one side is opened b
Maeda Yoshihide
Meistrick Zdenek
Torisaka Hisaki
Collier Shannon Scott PLLC
Corrigan Jaime
Denion Thomas
Diesel Engine Retarders, Inc.
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