FLUID-BIASED HYDRAULIC CONTROL VALVE
TECHNICAL FIELD
[0001] The present invention relates to an electrically operated hydraulic
control mechanism such as a solenoid valve.
BACKGROUND OF THE INVENTION
[0002] Solenoid control valves for hydraulic control systems are used to control
oil under pressure that may be used to switch latch pins in switching lifters and lash
adjusters in engine valve systems. Valve lifters are engine components that control the
opening and closing of exhaust and intake valves in an engine. Lash adjusters may also
be used to deactivate exhaust and intake valves in an engine. Engine valves may be
selectively deactivated or locked out to disable operation of some cylinders in an engine
when power demands on an engine are reduced. By deactivating cylinders, fuel
efficiency of an engine may be improved.
[0003] Engine deactivating solenoid control valves must operate with minimum
response times to maximize engine efficiency. Valve response times include valve
activation response times and deactivation response times. Solenoid control valves
apply a magnetic force to an armature that moves a control valve stem by activating a
coil to move the armature against a biasing force that is typically provided by a spring.
The magnetic force applied by the solenoid to the armature and in turn to the control
valve stem should be maximized to reduce response time. The magnetic force applied
by the coil can be increased by increasing the size of the coil. However, cost and
weight reduction considerations tend to limit the size of the coil. Deactivation response
times are adversely impacted by valve closure biasing springs, the force of which must
be overcome before the valve is opened. While this delay in response times in most
applications is minimal, in variable valve actuation systems, the limited time window
for valve activation and deactivation is critical and must be minimized.

SUMMARY OF THE INVENTION
[0004] A hydraulic control valve is provided having a solenoid body, an
energizable coil, and an armature positioned adjacent the coil. A valve stem extends
from the armature. The coil is energizable to move the armature and the valve stem
from a first position to a second position. The first position may be a deenergized,
closed position, and the second position may be an energized, open position. The valve
body, the armature and the valve stem are configured so that the armature and the valve
stem are biased to the first position by pressurized fluid, allowing the armature to
operate without a biasing spring. Thus, the armature is configured so that the net fluid
forces contribute to closing the valve, providing a relatively quick valve actuation
response time. If no biasing spring is used, cost and assembly time, as well as response
time, are minimized. Additionally, the solenoid may be weaker, and therefore less
expensive, as no spring biasing force needs to be overcome.
[0005] In one embodiment, the armature and the valve stem include a first
poppet and a second poppet, and the valve body defines a supply chamber with a first
seat, a second seat, and a control chamber between the first and second seats. The
first poppet is configured to sit at the first seat and the second poppet is configured to
be spaced from the second seat in the first position to prevent pressurized fluid flow
past the first seat and to exhaust fluid from the control chamber past the second seat.
The first poppet is configured to be spaced from the first seat and the second poppet is
configured to sit at the second seat in the second position to permit flow of pressurized
fluid from the supply chamber to the control chamber and prevent flow from the control
chamber to the exhaust chamber.
[0006] The hydraulic control valve may be mounted to an engine such that the
armature falls to the second position when the engine is off and the coil is not
energized, thereby moving the first poppet off of the seat to open the supply chamber to
the control chamber. Thus, due to gravity, the armature is in the same position as the
energized, engine -on position when the engine is off and the coil is not energized.

When the engine is subsequently restarted, with the coil still deenergized, air can
thereby expel from the supply chamber to the control chamber, and further to the
exhaust when the armature and valve stem move to the first position due to pressurized
oil acting on the second poppet. Expelling any air in the system enables a quicker,
more controlled response of the valve.
[0007] A hydraulic control circuit is provided with an electromagnetic actuator
selectively actuatable to create a flux path, a valve body having a seat past which a fluid
under pressure is selectively permitted to flow, and an armature that is selectively
moved in a first direction by electromagnetic flux. The armature defines a poppet that
is moved in the first direction relative to the seat from a closed position in which fluid
flow past the seat is prevented to an open position in which fluid flow past the seat is
permitted, the armature being biased to the closed position by operation of the fluid
under pressure.
[0008] The above features and advantages and other features and advantages of
the present invention are readily apparent from the following detailed description of the
best modes for carrying out the invention when taken in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIGURE 1 is a perspective view of a solenoid valve;
[0010] FIGURE 2 is an exploded perspective view of the solenoid valve shown
in Fig. 1;
[0011] FIGURE 3 is a cross-sectional view taken along the plane of section line
3-3 in Fig. 1 showing the valve in a first, closed and deenergized position; and
[0012] FIGURE 4 is a partial cross-sectional view similar to Figure 3 of the
valve in a second, open and energized position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Referring to Fig. 1, a solenoid valve 10, for example, such as that used
to deactivate lifters or operate a dual lift system in an internal combustion engine or
diesel engine is illustrated. The solenoid valve 10 may also be referred to as an
electromagnetic actuator. The solenoid valve 10 is installed in an engine 12. The
solenoid valve 10 includes a solenoid portion 16 and a valve body 18.
[0014] Referring to Figs. 2 and 3, the solenoid valve 10 is shown to include a
solenoid can 20 that houses a coil 22 that powers the solenoid valve 10. A pole piece
24 is assembled within the solenoid can 20. The pole piece 24 defines part of the flux
path for the coil 22. A flux collector insert 26 is disposed within the solenoid can 20
and also forms part of the flux path for the coil 22.
[0015] An armature 28 is acted upon by the flux created by energizing the coil
22 to shift the solenoid valve 10 from a normally closed position as shown in Fig. 3 to
the open position as shown in Fig. 4. An air gap 30 is provided between a radially-
extending face 31 of the pole piece 24 and a radially-extending face 33 of the armature
28. The air gap 30 may be adjusted by adjusting the pole piece 24 relative to the
armature 28. A relief groove 34, shown in Fig. 2, is provided in the armature 28 that
facilitates flow of oil under pressure axially across the armature 28. The relief groove
34 is also referred to as a conduit. Alternatively, a conduit may be formed in the valve
body 18 adjacent the armature 28 to provide flow of pressurized oil across the armature
28. The flux collector insert 26 may be inserted adjacent to the coil 22 and the valve
body 18 in a molded one-piece or multiple-piece body 40.
[0016] The valve body 18 defines an oil intake chamber 41, also referred to as a
supply chamber, in which the armature 28 is disposed and that initially receives oil
under pressure. The valve body also defines an intermediate chamber 42, also referred
to as a control chamber. A plurality of O-ring grooves 43 are provided on the exterior
of the valve body 18 that each receives one of a plurality of seals 44. The seals 44
establish a seal between the valve portion 18 and die engine 12. The molded body 40
defines an internal coil receptacle 46, or bobbin, that extends into the solenoid portion
16. The coil 22 is shown only in part, but it is understood that the coil 22 fills the coil

receptacle 46. The body 40 may be formed as a one-piece integral plastic molded part,
as illustrated, or could be formed in pieces and assembled together. The coil 22 is
wrapped around the coil receptacle 46.
[0017] A valve stem 48 has a portion 50 that is received within an opening 52 in
the armature 28. The position of the control valve stem 48 may be adjusted relative to
the armature 28 by a threaded connection or by a press-fit between the stem 48 and the
armature 28. The armature 28 includes a poppet 54 that is moved relative to the valve
seat 56 in response to pressure changes, as will be more fully described below. An
exhaust poppet 60 is provided on one end of the control valve stem 48 to move relative
to a valve seat 62 to open and close an exhaust port 70.
[0018] A supply gallery 64 is provided in the engine 12 to provide pressure P1
to the oil intake chamber 41 that is defined in the valve body 18. A control gallery 68
is provided in the engine 12 that is normally maintained at control pressure P2. An
exhaust gallery 71, also provided in the engine, is in communication with the exhaust
port 70 and is ported to ambient pressure and may be referred to as "Po". The
intermediate chamber 42 goes to Pressure Po when the exhaust port 70 is opened.
[0019] Referring to Fig. 4, the solenoid valve 10 is shown in the open position.
The coil 22 is energized to retract the armature 28 toward the coil 22. The poppet 54
opens the valve seat 56 to provide pressure P1 from the oil intake chamber 41 to the
intermediate chamber 42, and the exhaust poppet 60 sits at seat 62 to close the exhaust
port 70.
[0020] Referring to Figs. 2-4, the valve body 18 includes a supply opening 63
that receives oil under pressure from a supply gallery 64 that is in communication with
the oil intake chamber 41 and the valve seat 56. When the valve seat 56 is open, the
intake chamber 41 is in communication with the intermediate chamber 42. Oil under
pressure is provided through an oudet opening 66, also referred to as a control port,
and to a control gallery 68. An exhaust port 70 is provided at the inboard end of the
valve body 40. Exhaust port 70 is in communication with exhaust gallery 71.

[0021] In operation, the valve 10 is normally closed as shown in Fig. 3 and is
shifted to its open position as shown in Fig. 4 by energizing the coil 22. The coil 22,
when energized, reduces the air gap 30 formed between the pole piece 24 and the
armature 28. The armature 28 is shifted toward the pole piece 24 by electromagnetic
flux created by the coil 22. Oil in chamber 41 is in communication with the gap 30
through the relief groove 34.
[0022] When in the normally closed position shown in Fig. 3, the poppet 54
closes the valve seat 56, isolating the oil intake chamber 41, which is at P1, from the
intermediate chamber 42, which is at P2. The oil under pressure in the oil intake
chamber 41 biases the poppet 54 against the valve seat 56. The area of the armature 28
affected by P1 biases the armature to the closed position as P1 acts on the larger surface
area of face 33 of the armature 28 at the gap 30 to provide biasing force in one
direction (i.e., in a direction to seat the poppet 54 at the seat 56, while pressurized fluid
at P1 acts on a smaller surface area 73 of the armature in the chamber 41 in an opposing
direction. The biasing force applied to the poppet 54 is intended to eliminate the need
for a spring. Alternatively, a spring (not shown) may be incorporated to increase the
biasing force applied to the poppet 54.
[0023] When the coil 22 is energized, flux through the pole piece 24 and flux
collector insert 26 pulls the armature 28 toward the pole piece 24, as shown in Fig. 4.
The face-to-face orientation of the armature 28 relative to the pole piece 24 subjects the
armature 28 to exponentially greater magnetic force. Shifting the armature 28 causes
the poppet 54 to open relative to the valve seat 56, thereby providing pressure P1 from
the oil intake chamber 41 to the intermediate chamber 42. The intermediate chamber
42 is normally maintained at pressure P2but is increased to P1 when the poppet 54
opens the valve seat 56 and the poppet 60 closes valve seat 62 to close off the exhaust
port 70. Thus, P1 acts on the surface area of face 33 of the armature 28 and the surface
area 72 of the poppet 54 in one direction and on annular surface area 73 and surface
area 74 of poppet 54 in an opposing direction. Because the affected surface area 33 is
equal to the combined surface areas 73 and 74, me net force is that on surface area 72.

This change in pressure increases the hydraulic pressure supplied to the engine valve
system to P1. When the pressure provided to the engine valve system changes to P1,
selected engine valves may be deactivated by latch pins, lash adjusters or another
controlled device (not shown) to thereby deactivate selected cylinders of the engine.
[0024] When the coil 22 is subsequently deenergized, with the forces due to the flux
removed (i.e., the net force pulling the armature 28 toward the pole piece 24), the net
fluid pressure on surface area 33 drives the armature 28 to the normally closed,
deenergized position of Fig. 3. Thus, the armature 28 is configured so that the net
fluid forces (i.e., net downward force acting on face 72) contributes to closing the valve
10, with the chamber 42 exhausting to exhaust port 70, thereby providing relatively
quick valve actuation response time from the energized to the deenergized position.
[0025] The valve 10 is provided with an air purging and self-cleaning feature.
Specifically, the armature 28 is formed with a bypass slot 53, also referred to as a
bypass channel, to permit a limited amount of oil to move from chamber 41 to chamber
42 when me valve 10 is closed, bypassing the seat 54. Alternatively, the bypass slot
may be provided in the body 18 adjacent the seat 54. The slot 53 also allows particles
of dirt to be expelled from chamber 41 with the oil, and thus functions as a "self-
cleaning" feature of the valve. Additionally, air is purged from the chamber 41
through slot 53, thus preventing an air cushion acting against valve 10 moving to the
energized position of Figure 4 when the coil 22 is subsequently energized. This allows
quick transitioning from the deenergized to the energized position.
[0026] When the engine 12 is off so that no fluid pressure is provided in the
valve 10 and the coil 22 is deenergized, assuming that the valve 10 is installed in the
engine 12 with the armature 28 above the pole piece plug 24 (i.e., upside down with
respect to the view shown in Figs. 3 and 4), gravity will cause the armature 28 to fall to
the energized position of Fig. 4 (almough the coil is not energized). Thus, when the
engine 12 is started, pressurized oil will come up the supply gallery 64 and force any
air ahead of it out of the supply chamber 41 to the control chamber 42, past the open
seat 56 as me oil proceeds into chamber 41 and gap 30, biasing the armature 28 to the

closed, deenergized position of Fig. 3. The air is expelled from chamber 42 to exhaust
port 70 as the poppet 62 unseats.
[0027] While the best modes for carrying out the invention have been described
in detail, those familiar with the art to which this invention relates will recognize various
alternative designs and embodiments for practicing the invention within the scope of the
appended claims.

We Claim:
1. A hydraulic control valve (10) comprising:
a solenoid body (18);
a selectively energizable coil (22);
an armature (28) positioned adjacent the coil and having a valve stem
(48) extending therefrom; the coil being energizable to move the armature and the valve
stem from a first position to a second position;
wherein the valve body, the armature and the valve stem are configured
so that the armature and the valve stem are biased to the first position by pressurized
fluid.
2. The hydraulic control valve of claim 1, wherein the hydraulic
control valve is characterized by the absence of a spring biasing the armature and valve
stem to the first position.
3. The hydraulic control valve of claim 1, wherein the armature and
the valve stem include a first poppet (54) and a second poppet (60); wherein the valve
body defines a supply chamber (41) with a first seat (56), a second seat (62), and a
control chamber (42) between the first and second seats; wherein the first poppet is
configured to sit at the first seat and the second poppet is configured to be spaced from
the second seat in the first position to substantially prevent pressurized fluid flow past
the first seat and to exhaust fluid from the control chamber past the second seat;
wherein the first poppet is configured to be spaced from the first seat and the second
poppet is configured to sit at the second seat in the second position to permit flow of
pressurized fluid from the supply chamber to the control chamber and prevent flow
from the control chamber to an exhaust port.

4. The hydraulic control valve of claim 3, in combination with an
engine; wherein the hydraulic control valve is mounted to the engine such that the
armature falls to the second position when the engine is off and the coil is not
energized, thereby moving the first poppet off of the seat to open the supply chamber to
the control chamber, air thereby expelling from the supply chamber to the control
chamber and further expelling to the exhaust port when the armature and valve stem
move to the first position when the engine is restarted.
5. The hydraulic control valve of claim 4, wherein the armature is
configured so that an additional area of the second poppet is exposed to pressurized
fluid when the armature transitions from the second position to the first position,
thereby biasing the armature to the first position.
6. The hydraulic control valve of claim 4, wherein one of the valve
body and the first poppet form a bypass channel (53) at the first seat, allowing air to
bleed from the supply chamber to the control chamber through the bypass channel when
the valve is in the first position.
7. The hydraulic control valve of claim 1, further comprising:
a pole piece (24) positioned to establish a gap (30) between the pole
piece and the armature; wherein the armature is configured to route pressurized fluid
between the gap and a side of the armature opposite the pole piece and the gap; wherein
a first area of the armature exposed to pressurized fluid in the gap is greater than a
second area of the armature exposed to pressurized fluid at the side of the armature
opposite the gap, the armature thereby being biased away from the pole piece by the
fluid.

8. The hydraulic control valve of claim 7, wherein the area exposed
to fluid force biasing the valve to the first position increases as the valve transitions
from the second position to the first position and the gap between the armature and the
pole piece increases.
9. A hydraulic control circuit comprising:
an electromagnetic actuator (10) selectively actuatable to create a flux
path, the actuator including;
a valve body (18) having a seat (56) past which fluid under
pressure is selectively permitted to flow; and
an armature (28) that is selectively moved in a first direction by
electromagnetic flux, the armature defining a poppet (54) that is moved in the first
direction relative to the seat from a closed position in which fluid flow past the seat is
substantially prevented to an open position in which fluid flow past the seat is
permitted, the armature being biased to the closed position by operation of the fluid
under pressure.
10. The hydraulic control circuit of claim 9, wherein the poppet is a
first poppet; wherein the valve body defines a second seat (62); wherein the armature is
connected to a valve stem (48) that defines a second poppet (60) that is moved with the
armature in the first direction relative to the second seat from a first position in which
fluid flow past the second seat is permitted to a second position in which fluid flow past
the second seat is prevented; and wherein the second poppet is biased toward the first
position when the armature is biased toward the closed position by the fluid under
pressure.
11. The hydraulic control circuit of claim 10, wherein the first poppet
and the second poppet are held in a fixed spatial relationship by the valve stem.

12. The hydraulic control circuit of claim 9, wherein the
electromagnetic actuator is a solenoid valve that includes a coil (22) that is energizable
to create the flux.
13. The hydraulic control circuit of claim 9, wherein the valve body
defines a first chamber (41) to which pressurized fluid is provided through a supply
port (63); wherein the valve body further defines a second chamber (42) from which
fluid exhausts to an exhaust port (70); and wherein the second chamber is in fluid flow
communication with the first chamber when fluid is permitted to flow past the seat.
14. The hydraulic control circuit of claim 13, wherein the armature is
connected to a valve stem (48) that defines a second poppet (60) that is moved with the
armature relative to the exhaust port between a closed position and an open position in
the first direction, wherein the first poppet is open when the second poppet closes the
exhaust port and the first poppet is closed when the second poppet opens the exhaust
port.
15. A hydraulic control valve comprising:
an energizable coil (22) and an armature (28);
a valve body (18) defining a valve seat (56), an exhaust seat (62), a
supply port (63), a control port (66), and an exhaust port (70);
wherein the armature includes a first poppet (54) seated at the valve seat
when the coil is not energized and substantially preventing pressurized fluid flow from
the supply port past the valve seat to the control port; wherein the armature is shifted
within the valve body by a magnetic force generated by the energized coil to move the
first poppet away from the valve seat to allow fluid flow from the supply port to the
control port;

a valve stem (48) assembled to the armature and having an exhaust
poppet (60) that is spaced from the exhaust seat when the coil is not energized to allow
fluid flow from the control port to the exhaust port, and is seated at the exhaust seat to
prevent fluid flow from the control port to the exhaust port when the coil is energized.
16. The hydraulic control valve of claim 15, wherein the armature is
configured so that an additional area of the second poppet is exposed to pressurized
fluid when the armature transitions from a second position in which the coil is
energized to a first position in which the coil is not energized, thereby biasing the
armature to the first position.
17. The hydraulic control valve of claim 15, wherein one of the valve
body and the first poppet form a bypass channel (53) at the first seat, allowing air to
bleed from the supply port to the control port through the bypass channel when the
valve is in a first position in which the coil is not energized.
18. The hydraulic control valve of claim 17, wherein an area of the
exhaust poppet exposed to fluid force biasing the valve to the first position increases as
the valve transitions from a second position in which the coil is energized to the first
position and a gap (30) between the armature and the pole piece increases.

ABSTRACT

A hydraulic control valve (10) is provided having a solenoid body (18),
an energizable coil (22), and an armature (28) positioned adjacent the coil. A valve
stem (48) extends from the armature. The coil is energizable to move the armature and
the valve stem from a first position to a second position. The valve body, the armature
and the valve stem are configured so that the armature and the valve stem are biased to
the first position by pressurized fluid, allowing the armature to operate without a
biasing spring.