Pressure balanced spool poppet valves with printed actuator coils
Pressure balanced spool poppet valves with printed actuator coils minimize valve leakage and facilitate efficient manufacturing and reliable operation. The spool poppet valves may be configured like a conventional spool valve, but further include a poppet valve at one end of the spool to proved much better sealing when the poppet valve is closed. Various features are disclosed, including pressure balancing for high pressure operation. The printed actuator coils for the spool poppet valves are formed by the interconnection of conductive coils on each of multiple layers of a multiple layer printed circuit board, which circuit board may have a hole there through for accommodation of mechanical and/or magnet requirements, and may include similar printed actuator coils for one or more additional spool poppet valves as well as electronic devices associated with the operation thereof. The spool poppet valves may be advantageously constructed without printed actuator coils, and the printed actuator coils may be advantageously used in actuators of other designs.
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This application claims the benefit of U.S. Provisional Patent Application No. 60/738,859 filed Nov. 21, 2005.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to the field of valves, and systems using a plurality of solenoid actuators.
2. Prior Art
Embodiments of the present invention provide improved devices for fluid control in various applications. Typical examples include the control of a high pressure fuel injector, and hydraulic engine valve actuation systems. Two-way poppet valves (open and closed) are often used due to their low leakage characteristics. In many applications, it is highly desirable to use a three-way valve for improved performance and control, but this is difficult due to a three-way valve's inability to pressure balance completely unless it is a spool valve, which leaks excessively. For purposes of this disclosure, a three-way valve will be described as a valve coupling a source (S) passage to a control (C) passage or coupling the control passage to a vent (V), though other port identifications may be more appropriate depending on the use of the three-way valve.
The choices for a three-way valve are:
Spool valve. A spool valve can create the required hydraulic paths, but while in either position (S-C or C-V) the valve has a very short leak (seal) path from a high-pressure area to a vented area, which can lead to high system parasitic losses. This valve can be designed to have a hydraulic short circuit (momentarily coupling of source and vent when transitioning from one position to the other) or not, depending on the application. The advantages are primarily in its pressure balance, thereby requiring very low actuation forces, and in the ability to be designed to avoid the short circuit.
Three-way hard-seat valve (Poppet). This type of valve can have no leakage in either position, but when the valve is transitioning from one position to the other, there necessarily exists a direct flow path between the source and the vent that could lead to large losses of energy and system noise. This type of valve cannot be completely pressure balanced, and therefore requires greater actuating forces than a typical pressure balanced spool valve.
Two two-way hard-seat valves (Poppet). This option has no leakage and can have a direct flow path between the source and the vent or not, depending on control of the system. The disadvantage of this system is that twice as many control valves are needed to achieve three-way control, adding system and control complexity, and further requiring more room to package.
Thus the current choices and their disadvantages are:
Spool Valve: High static leakage.
Three-way hard-seat valve: High actuating force requirements (due to pressure imbalance) and short circuit loss.
Two, two-way hard seat valves: Cost and complexity.
Solenoid actuators for valves of various types are also well known. Such actuators may be single coil spring return, with or without magnetic latching or double coil, with or without magnetic latching (see U.S. Pat. Nos. 3,743,898 and 5,640,987). However configured, solenoid actuators generally have a relatively simple mechanical configuration, with the solenoid coils being relatively inexpensive to wind. However, in certain applications, the number of solenoid actuated valves preferably used may be relatively large, giving rise to quite a substantial wiring problem. Superimposed on this in certain applications is a combination of heat and vibration that can cause premature wiring failure, and thus possibly giving rise to unsatisfactory reliability of the system. One such application to which preferred embodiments of the present invention are directed is in diesel engines, and more specifically, to hydraulic engine valve actuation systems as are currently in development, and diesel engine fuel injection systems, as well as fuel air cells incorporating both hydraulic engine valve actuation and fuel injection in a single assembly for each engine cylinder. Because most diesel engines are multiple cylinder engines, such as 6 and 8 cylinder engines, each having intake valves, exhaust valves and a fuel injector, all three of which must be independently controlled for each cylinder, and preferably for greater flexibility each engine valve actuator and each fuel injector will have more than one solenoid valve, the number of solenoid valves preferably used in a multi-cylinder engine can be quite substantial. Accordingly, wiring of the individual solenoid coils to a harness for connection to a control box would be complicated and expensive and may not have the reliability inherent in the rest of the diesel engine.
BRIEF DESCRIPTION OF THE DRAWINGS
First referring to
At the right end of spool 26 is a magnetic armature 28 urged against end 34 of the spool by a pressure balance piston 36, the right end of which is also subjected to the fluid pressure of the supply S. The diameter of the pressure balance piston 36 is the same as the outer diameter of the spool 26, thus substantially equal to the inner diameter of the housing 20 and cap 22. This, coupled with the fact that the angle of the valve seat 32 is slightly greater than the angle of the poppet valve 28 so that the poppet valve seals on the edge of the bore in the housing 20, means that the spool poppet valve is pressure balanced, the pressure of the supply S on the poppet valve 28 acting over the same area as the fluid in supply S acting on the end of pressure balance piston 36.
When a current is passed through coil 38, the armature 28 is attracted to the left, overcoming the force of spring 30 to move the spool to a left-most position when the armature 28 is attracted flat against the end of housing 20. In this position, a magnetic circuit is established through housing 20 and armature 28 that has a substantially zero air gap. Thus in this position, the armature 28 may be retained by residual magnetism in the housing 20 and armature 28, or alternatively, by a small holding current in coil 38, depending on the relative forces between spring 30 and the holding force of the residual magnetism. Obviously, when the spool moves to the left position, in this embodiment the coupling from the control C to the vent V is first discontinued as poppet valve opens, and then coupling from the control port C to the supply port S is opened by the spool. Alternatively, if one wanted, one could simultaneously close one port and open the other, or as a further alternative, open the coupling between the control port C and the supply port S before closing the coupling between the control port C and the vent, though usually this is undesirable because of the loss of energy by the momentary coupling of the supply port S directly to the vent port V.
An advantage of the spool poppet valve of
Another aspect of the present invention is a construction of the actuator coils 38 in the valve of
By way of specific example, an exploded view of a portion of a multi-layer printed circuit board can be seen in
The coils shown in
An exemplary application of this embodiment of the present invention is schematically shown in
The advantage of an embodiment of the general type shown in
The printed solenoid coil aspect of the present invention has been illustrated herein schematically. By way of example,
Thus the present invention has a number of aspects, which aspects may be practiced alone or in various combinations or sub-combinations, as desired. Also while certain preferred embodiments of the present invention have been disclosed and described herein for purposes of illustration and not for purposes of limitation, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
Claims
1. A valve comprising:
- a spool valve body having a poppet valve seat at one end thereof, the spool valve body having a source port for coupling to a source of fluid under pressure at one side of the poppet valve seat, and a control port and a vent port on the other side of the poppet valve seat;
- a spool within the spool valve body having a poppet valve at a first end thereof cooperatively disposed to engage the poppet valve seat when the spool is in a first position to seal;
- the spool and spool valve body coupling the control port to the vent port and blocking the source port from the control port when the spool is in the first position; and,
- the spool and spool valve body coupling the source port to the control port and blocking the control port from the vent port when the spool is in a second position;
- whereby fluid flow from the source port to the control port or vent port when the spool is in the first position is blocked by both the poppet valve resting on the poppet valve seat and by the spool and spool valve body.
2. The valve of claim 1 wherein the angle of the poppet valve seat is slightly greater than the angle of the poppet valve so that the poppet valve seals on the edge of a bore in the spool valve body.
3. The valve of claim 2 further comprised of a hydraulic surface adjacent a second end of the spool exposed to the source of fluid under pressure.
4. The valve of claim 3 wherein the hydraulic surface has an area equal to the area of the bore in the spool valve body, thereby pressure balancing the spool when in the first position.
5. The valve of claim 1 further comprised of an actuator to controllably move the spool to the second position, and a return to return the spool to the first position when the actuator is not active.
6. The valve of claim 5 wherein the return is a return spring.
7. The valve of claim 5 wherein the actuator is an electromagnetic actuator.
8. The valve of claim 7 wherein the actuator is a magnetic latching actuator.
9. The valve of claim 7 wherein the actuator moves the spool to the second position and retains the spool in the second position using a relatively high current pulse to move the spool to the second position followed by a relative low holding current to retain the spool in the second position.
10. The valve of claim 7 wherein the electromagnetic actuator includes at least one actuator coil formed by the interconnection of conductive coils on each of multiple layers of a multiple layer printed circuit board.
11. The valve of claim 10 wherein the multiple layer printed circuit board includes at least one additional actuator coil formed by the interconnection of additional conductive coils on each of multiple layers for another valve having an electromagnetic actuator.
12. The valve of claim 10 wherein the multiple layer printed circuit board has an opening through the center of the actuator coil.
13. A valve comprising:
- a spool valve body having a poppet valve seat at one end thereof, the spool valve body having a source port for coupling to a source of fluid under pressure at one side of the poppet valve seat, and a control port and a vent port on the other side of the poppet valve seat;
- a spool within the spool valve body having a poppet valve at a first end thereof cooperatively disposed to engage the poppet valve seat when the spool is in a first position to seal between the poppet valve and the poppet valve seat, a hydraulic surface adjacent a second end of the spool for coupling to the source of fluid under pressure;
- the spool and spool valve body coupling the control port to the vent port and blocking the source port from the control port when the spool is in the first position;
- the spool and spool valve body coupling the source port to the control port and blocking the control port from the vent port when the spool is in a second position; and,
- an actuator to controllably move the spool to the second position, and a return to return the spool to the first position when the actuator is not active;
- whereby fluid flow from the source of fluid under pressure to the control port or vent port when the spool is in the first position is blocked by both the poppet valve resting on the poppet valve seat and by the spool and spool valve body.
14. The valve of claim 13 wherein the angle of the poppet valve seat is slightly greater than the angle of the poppet valve so that the poppet valve seals on the edge of a bore in the spool valve body.
15. The valve of claim 14 wherein the hydraulic surface has an area equal to the area of the bore in the spool valve body, thereby pressure balancing the spool when in the first position.
16. The valve of claim 13 wherein the return is a return spring.
17. The valve of claim 13 wherein the actuator is an electromagnetic actuator.
18. The valve of claim 17 wherein the actuator is a magnetic latching actuator.
19. The valve of claim 17 wherein the actuator moves the spool to the second position and retains the spool in the second position using a relatively high current pulse to move the spool to the second position followed by a relative low holding current to retain the spool in the second position.
20. The valve of claim 17 wherein the electromagnetic actuator includes at least one actuator coil formed by the interconnection of conductive coils on each of multiple layers of a multiple layer printed circuit board.
21. The valve of claim 20 wherein the multiple layer printed circuit board includes at least one additional actuator coil formed by the interconnection of additional conductive coils on each of multiple layers for another valve having an electromagnetic actuator.
22. The valve of claim 21 wherein the multiplayer printed circuit board includes electronic devices associated with the operation of the valves.
23. An electromagnetic actuator comprising:
- a stationary magnetic member;
- a moveable magnetic member moveable from a first position to a second position in response to a magnetic field linking the stationary magnetic member and the moveable magnetic member;
- an actuator coil disposed to cause a magnetic field linking the stationary magnetic member and the moveable magnetic member as a result of a current in the actuator coil;
- the actuator coil being formed by the interconnection of conductive coils on each of multiple layers of a multiple layer printed circuit board.
24. The electromagnetic actuator of claim 23 wherein the multiple layer printed circuit board has an opening through the center of the actuator coil.
25. The electromagnetic actuator of claim 23 wherein the multiple layer printed circuit board includes at least one additional actuator coil formed by the interconnection of additional conductive coils on each of multiple layers for another valve having an electromagnetic actuator.
26. The electromagnetic actuator of claim 25 further comprised of at least one electronic device associated with operation of a electromagnetic actuator mounted on the printed circuit board.
27. The electromagnetic actuator of claim 23 further comprised of at least one electronic device associated with operation of the electromagnetic actuator mounted on the printed circuit board.
Type: Application
Filed: Nov 16, 2006
Publication Date: May 24, 2007
Applicant:
Inventors: Oded Sturman (Woodland Park, CO), Steven Massey (Woodland Park, CO)
Application Number: 11/601,476
International Classification: F15B 13/044 (20060101);