Electronic valve actuator
Electromagnetic actuators are described for operating poppet valves in internal combustion engines.
This application claims the benefit under 35 U.S.C. §119(e) of:
- U.S. Provisional Application No. 60/551,199 filed Mar. 8, 2004,
- U.S. Provisional Application No. 60/566,112 filed Apr. 28, 2004,
- U.S. Provisional Application No. 60/574,414 filed May 24, 2004,
- U.S. Provisional Application No. 60/578,548 filed Jun. 10, 2004,
- U.S. Provisional Application No. 60/605,943 filed Aug. 31, 2004, and
- U.S. Provisional Application No. 641,225 filed Jan. 4, 2005, and
- this application claims the benefit under 35 U.S.C. §120 of:
an Patent Cooperation Treaty application filed on the same day (Mar. 7, 2005) as this application, entitled “Induction Sensor”, by the same inventors as this application, all of which applications are hereby incorporated by reference.
This invention has been created without the sponsorship or funding of any federally sponsored research or development program.
BACKGROUND OF THE INVENTIONSolenoid systems for electromagnetic actuation of engine valves are well known in the art. These systems are required to move a valve between open and closed positions that are far apart in a short time. Previous designs have relied on mechanical springs to store part of the energy in the system in order to lessen the power requirement of the solenoid and to improve control of valve's acceleration and deceleration. It would be desirable to develop a system that would make it practical to eliminate the mechanical spring used in an electromagnetic valve actuator.
Since the magnetic attractive force between two parallel surfaces decreases as the distance increases by the square of the distance and the force is proportional to the area of the surfaces, the magnetic interaction between conventional flat to parallel surfaces employed and prior art designs impose serious limitations. It would be desirable to develop geometric techniques that would increase the effective power of the solenoid system and improve energy efficiency.
Thus, existing actuators employ mechanical springs that complicate and increase the cost of the actuators and contribute to maintenance difficulties. Furthermore, existing actuators employ the solenoid systems that are not efficient producers of force and therefore also complicate increase the cost of the actuators and contribute to maintenance difficulties.
These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the present invention to provide an actuator which increases electromagnetic effectiveness over the range of movement.
Another object of this invention is to provide an actuator this simple in construction in design.
A further object of the present invention is to provide an actuator which is compacted in design and therefore allows a high degree of flexibility in integrating the actuator into mechanical systems.
It is another object of the invention is to provide an actuator that allows precise and reproducible motion.
It is a further object of the invention to provide an actuator that is capable of being manufactured of high quality and at a low cost, and which is capable of providing a long and useful life with a minimum of maintenance.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.
BRIEF SUMMARY OF THE INVENTIONThis invention is a valve actuator for controlling movement of poppet valves (inlet valve and exhaust valve) and internal combustion engines. The actuator includes an armature is mounted on the stem of the valve. The armature has a convex surface on its front and a convex on the rear. In one embodiment the surfaces would be tapered with a wedge shape. The taper would be approximately eighteen degrees from the axis of the valve stem. The actuator also includes electromagnets with concave surfaces that conformed to the convex surfaces of the armature. The electromagnets are arranged so that they can be selectively activated to cause movement of the valve. The complementary geometry of the armatures and magnets enhance the effectiveness of the magnetic field cost by the electromagnets on the armature.
BRIEF DESCRIPTION OF THE DRAWINGSThe character of the invention, however, may best be understood by reference to one of its structural forms, as illustrated by the accompanying drawings, in which:
In
Ft=Fa sin a
The result of this is that the solenoid system of
In one embodiment of this invention, the motion of the valve @@ from its open position to its closed position, is controlled through a the magnetic action of the coils by an electronic valve position controller @@. In one embodiment of this invention, the controller receives a signal from the valve position sensor @@. The signal is generated by the physical relationship between the tapered end 6 of the valve 15 and the valve position sensor coil 13. The signal is an accurate representation of the relative position of the valve in its range of movement. This signal allows the controller to recalibrate the position of the valve at its closed position during every valve opening cycle, and thereby more accurately control the movement of the valve. In this way, compensation for thermal expansion is determined and applied.
In one embodiment of the invention, the coupling 5 may be a rigid connection between the valve 15 and the armature shaft 4. This rigid connection is possible because the accuracy of the valve position sensor @@ allows a valve position controller @@ to recalibrate the position of the valve at its closed position during every valve opening cycle. In this way, compensation for thermal expansion is determined and applied, so the coupling 5 need not be expandable.
In some applications, it is possible to have the valve 15 extend through the armature and have no coupling 5 outside of the valve actuator. An example of this is when the valve material is titanium.
It is obvious that minor changes may be made in the form and construction of the invention without departing from the material spirit thereof. It is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.
Claims
1. A valve actuator with tapered armature as shown in FIG. 2.
2. A valve actuator with guides that absorb force normal to the valve motion.
3. A valve actuator with flux paths perpendicular to the direction of valve motion.
4. A valve actuator with integral valve stem and armature shaft.
5. An engine valve system for use in an engine, the system adapted for moving an engine valve between an open position and a closed position, comprising:
- a) an engine valve having a stem with an axis and a front end and a back end, the valve having a movement axis between the open position and closed position along the stem axis,
- b) an armature mounted on the stem of the valve, the armature having a front nonplanar surface directed to the front end of the valve stem up, and back nonplanar surface directed to the back end of the valve stem,
- c) a stator assembly mounted on the engine, the stator assembly being adapted to enclose the armature with the armature movable within the stator assembly, the stator assembly including a first magnetic field producing device including a first nonplanar surface of complementary shape to the front nonplanar surface of the armature, said first magnetic field producing device being adapted to selectively magnetically attracted the front nonplanar surface of the armature to the first nonplanar surface of the first magnetic field producing device, and the stator assembly also including a second magnetic field producing device including a second nonplanar surface of complementary shape to the back nonplanar surface of the armature, said second magnetic field producing device being adapted to selectively magnetically attract the back nonplanar surface of the armature to the second nonplanar surface of the second magnetic field producing device.
6. An actuator for use in an engine, the system adapted for moving an engine valve between an open position and a closed position, said engine valve having a stem with an axis and a front end and a back end, the valve having a movement axis between the open position and closed position along the stem axis, comprising:
- a) an armature mounted on the stem of the valve, the armature having a front nonplanar surface directed to the front end of the valve stem up, and back nonplanar surface directed to the back end of the valve stem, and
- b) a stator assembly mounted on the engine, the stator assembly being adapted to enclose the armature with the armature movable within the stator assembly, the stator assembly including a first magnetic field producing device including a first nonplanar surface of complementary shape to the front nonplanar surface of the armature, said first magnetic field producing device being adapted to selectively magnetically attracted the front nonplanar surface of the armature to the first nonplanar surface of the first magnetic field producing device, and the stator assembly also including a second magnetic field producing device including a second nonplanar surface of complementary shape to the back nonplanar surface of the armature, said second magnetic field producing device being adapted to selectively magnetically attract the back nonplanar surface of the armature to the second nonplanar surface of the second magnetic field producing device.
Type: Application
Filed: Mar 7, 2005
Publication Date: Oct 20, 2005
Inventors: G. Taylor (Berlin, MA), Steven Beard (Berlin, MA)
Application Number: 11/074,370