Abstract:
A mechanically simplified electric and fluid (gas, vapor or liquid) control for a piston engine, including an engine valve actuator system that eliminates rotating cam shafts and heavy internal combustion engine valve closing springs by using an electromagnet and an armature which is attracted by the electromagnet to initiate movement of both a fluid control valve and the engine valve. When the control valve is moved only slightly off its seat by the armature, fluid pressure instantly drives the control valve a much greater distance closing the engine valve. Opening and closing time is regulated independently. Engine valves are opened by reversing the fluid pressure balance across the control valve at the time selected.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation-in-part of Ser. No. 13/532,853, filed Jun. 26, 2012, now U.S. Pat. No. 9,316,130, which is a continuation-in-part of application Ser. No. 12/959,025, filed Dec. 2, 2010, which in turn is a continuation-in-part of application Ser. No. 12/539,987, filed Aug. 12, 2009, which in turn is a continuation-in-part of application Ser. No. 12/492,773, filed Jun. 26, 2009 (now abandoned), a continuation-in-part of copending application Ser. No. 12/844,607, filed Jul. 27, 2010, a continuation-in-part of Ser. No. 12/387,113, filed Apr. 28, 2009 and Ser. No. 12/075,042, filed Mar. 7, 2008. 
     The applicants also claim the benefit of the following provisional applications: 61/309,640, filed Mar. 2, 2010; and 61/320,959, filed Apr. 5, 2010; and 60/905,732, filed Mar. 7, 2007, all of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to fluid-electric actuated valves for reciprocating piston engines such as internal combustion (I.C.) engine valves that are opened and closed by means of an electric current in combination with pressure applied by a fluid that may either be vapor such as steam a gas such as compressed air or a liquid such as hydraulic fluid. 
     BACKGROUND OF THE INVENTION 
     The electronic operation of reciprocating piston engine valves such as internal combustion engine valves offers the potential of advancing or retarding valve actuation (phase control) as well as the possibility of electronically tailoring the valve opening and closing time within each cycle of operation by means of the engine control unit computer to reach performance goals such as reduced fuel consumption that are unobtainable with variable camshaft phasing currently used for example in cars and trucks. 
     Several electrical and hydraulic systems have been proposed but none have been commercially successful with regard to cost and performance. Fully electric designs exemplified by U.S. Pat. Nos. 4,829,947; 6,220,210 and 6,237,550 have been proposed but have not been adapted for wide sale commercial use. The same is true of electrohydraulic internal combustion valve actuators such as those described in U.S. Pat. Nos. 5,509,637; 4,009,695; 6,604,497; 4,878,464; 4,974,495; 6,089,197; 7,063,054 or 7,347,171. Steam engine valves have been actuated by an electromagnet and by steam, e.g., U.S. Pat. No. 8,448,440 but steam is not available in cars or trucks and there is no internal combustion (I.C.) valve nor any recognition in the patent of applicability or benefit concerning internal combustion engines. 
     Existing I.C. valve actuator systems ordinarily require a heavy duty engine valve closing spring for applying a force of typically about 300 lb.-1000 lb. together with one or more solenoid operated hydraulic valves each connected by ducts to a hydraulic actuator piston which is, in turn, connected to the engine intake or exhaust valve. Besides being complicated in construction, the heavy valve seating springs can reduce valve cycling speed and contribute to valve actuator power requirements which are a function of the product of spring stiffness and the square of the valve lift. 
     In view of these and other deficiencies found in previous reciprocating engines such as internal combustion engine valves and actuators such as those proposed for use in vehicles, e.g., cars and trucks, it is a general object of the present invention to find a mechanically simplified yet more effective way to employ electric control of a fluid (gas such as air or a liquid) for regulating the opening and closing of internal combustion (I.C.) engine valves at different selected time intervals. 
     Another object is to be able to open and close I.C. valves at a significantly faster rate than is accomplished by the harmonic action of a camshaft. 
     Another object is to find a way to actuate I.C. valves using electronic triggering that is capable of operating the I.C. valves with variable phase control at a cycling rate of at least 60 Hz (7200 rpm for a four-stroke engine). 
     Still another object is to provide a fluid actuated I.C. valve in which fluid at supply pressure applies a selected I.C. opening force followed by a closing force great enough to achieve an abrupt closing action. 
     Still another object is to provide electromagnetic valve actuation with a significant valve lift, e.g., 10 mm or ⅜ inch, yet provide a magnetic traction force to initiate valve motion that is not significantly diminished by being applied in an area of reduced magnetic flux density. 
     Another object is to provide I.C. engine in which I.C. valve closing motion is initiated electrically and is continued in the same direction by the application of fluid pressure 
     Another object is to begin closure of the I.C. valve electrically and to open the valve by the application of fluid pressure at the end of a separately determined time period. 
     Another object of the invention is to operate I.C. engine valves using a single signal, e.g., an electrical current sufficient to initiate timed valve closure in which the timed opening step that follows continues automatically without a need to either engage further mechanical elements or provide added electronic input. 
     Yet another object of the invention is to close each I.C. valve entirely or almost entirely by fluid pressure rather than by using a heavy valve spring of the kind commonly found in I.C. engines thereby eliminating the resistance of a typical valve spring, reducing valve work and achieving higher cycling rates. 
     These and other more detailed and specific object and advantages of the present invention will be better understood by reference to the following figures and detailed description which illustrate by way of example but a few of the various forms of the invention within the scope of the appended claims 
     All citations listed herein are incorporated herein by reference as fully and completely as if reproduced herein in their entirety and specifically indicated to be incorporated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the invention installed on an engine; 
         FIG. 2  is a top view on a larger scale; 
         FIG. 3  is a semi-diagrammatic vertical sectional view of the invention taken on line  3 - 3  of  FIG. 2  with the internal combustion (I.C.) valve open; 
         FIG. 4  is a view similar to  FIG. 3  with the I.C. valve held closed by the control valve; 
         FIG. 5  is a side elevation of the valve train including I.C. valve, valve stem and control valve; 
         FIG. 6  is a vertical cross-section on line  6 - 6  of  FIG. 5 ; 
         FIG. 7  is a perspective view of the control valve stem and control valve spool; 
         FIG. 8  is a perspective view of the control valve sleeve; 
         FIG. 9  is a graph showing how the needle valve setting controls the time the I.C. engine valve closed and control valve is open; 
         FIG. 10  is a graph showing test results in timing a reciprocating control valve using a needle valve similar to that shown in  FIGS. 3 and 4 ; and 
         FIG. 11  is a diagram of a modified seat for the control valve spool 
     
    
    
     SUMMARY OF THE INVENTION 
     The present invention provides an actuator assembly for reciprocating piston engines such as internal combustion engines in which an electromagnet having an armature and a control valve having a valve piston or spool are all operatively associated with one another on a common valve stem that can transmit opening and closing motion to an internal combustion inlet or exhaust valve and yieldable biases the internal combustion valve to an open position. While having a simple mechanical construction the invention is able to eliminate the heavy closing spring commonly used on such inlet or exhaust valve while also eliminating cam shafts, push rods and rockers. In operation, the electromagnet armature when attracted by the electromagnet initiates movement of both the I.C. engine valve and fluid control valve by moving through a narrow air gap (typically less than 0.025 inch or 0.38 millimeter). After the control valve piston is thus moved slightly off its seat, pressurized fluid, e.g., air or hydraulic fluid is injected between the valve and its seat, instantly driving the spool the much greater distance required to seat the I.C. valve and continue to hold it closed for the rest of its cycle. An electronic control unit (ECU) controls the time the I.C. valve is allowed to remain closed. Fluid pressure is then balanced at both ends of the control valve piston (spool) which may have a different diameter at each end allowing an equal fluid pressure on the ends to drive the control valve spool in a reverse direction to open the I.C. valve. Both opening and closing events are controlled independently by the ECU thereby enabling the beginning, duration and end of the valve-open interval to each be changed separately as required to optimize engine operating conditions. Actuators according to the invention can also be used on other reciprocating piston engines such as steam engines. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows an internal combustion valve and actuator assembly  10  with an actuator casing  11  that is mounted on internal combustion (I.C.) engine  12 .  FIGS. 3 and 4  show how each I.C. engine valve  14  has a valve stem  14   a  and a securely connected control valve piston or spool  16 . Above valve spool  16  is an electromagnet  19  and armature  18 . The I.C. valve  14 , control valve spool  16  and armature  18  are all operatively connected to a common valve stem  14   a . An I.C. valve seat  12   a  is shown at the lower end of exhaust or intake passage  12   b . At its uppermost end the I.C. valve stem  14   a  has an enlarged stop  17  which can comprise a head element or threaded nut and lock nut  17   a , the lower or inward surface of which acts as an abutment that during operation is forced upwardly by contact with the upper surface of the electromagnet armature  18  as it raises the stem  14   a  and closes the I.C. valve  14 . The armature has a planar shape with a central hole  18   a  through which the I.C. engine stem  14   a  passes and is thus mounted loosely on stem  14   a . The armature is yieldably biased by springs  19   d  and  19   c  into a recess  24   a  within a cover  24  in a position that typically provides an air gap  18   b  which can be about 0.010 to 0.025 inch below a pole face on line A-B at bottom of electromagnet  19 . 
     The electromagnet  19  can be of various shapes such as rectangular or a donut-shape but preferably has a laminated E-shaped iron core as shown with poles as indicated and an electrical conductor winding  20 . The electromagnet  19  has a downwardly opening pocket  19   b  to provide space for the stop  17  when the valves  14 ,  16  and stem  14   a  are elevated. Both the electromagnet  19  and the springs  19   c  and  19   d  can be held inside a housing  19   e  which is bolted onto cover  24  at the top of the actuator casing  11  with a gasket G between them to hermetically seal the electromagnet to the top of the cover  24 . This prevents air leakage from the top of the actuator without the need for packing around the top of the stem  14   a . An O-ring  20   a  seals the cover  24  to the casing  11 . 
     Both the upper and lower sections of the control valve  16  are provided with compression rings R that seal the valve body and the surrounding bore. The lower edges of the bottom set of rings R can be chamfered to facilitate insertion. Alternatively, the casing  11  has a horizontal parting line (not shown) so that the rings can be more easily compressed as they are being inserted. The valve piston or spool  16  is sealingly and slidably mounted at its upper end within a sleeve  21  that is pressed into an upper bore  21   a  in the casing  11 . The lower end of valve body  16  is slidably and sealingly mounted in a coaxial lower bore  26  of a smaller diameter in the casing  11 . A partition P can be welded in place within the valve piston or spool  16  with a recess for spring  23 . The larger ID of the sleeve  21  makes it possible for the same fluid supply pressure at both ends of spool  16  to create a much greater downward force on the valve body so as to overcome the upward force from below thereby opening the I.C. valve. The ratios of the large and small diameter at the ends of the control spool  16  are arranged such that an initial increase in fluid pressure on the larger diameter in control cavity  27  the instant the spool is raised together with the force of the spring  23  as installed does not exceed the fluid force at the opposing lower end of the control valve  16 . In one prototype the large bore diameter was 2.25 inches and the lower bore was 2 inches. 
     Spool  16  is urged downwardly onto a tapered seat  16   b  by the compression spring  23  that can have a compressed force of about 20-30 lbs. The installed (minimum) force which can be in the range of 10-15 lbs. is arranged to exceed the efflux gas pressure on the head of the I.C. valve  14  during the exhaust stroke. 
     Inside the sleeve  21  within the casing  11  is a timing control cavity  27  above the valve spool  16  which when seated communicates via circumferentially distributed ports  21   c  in sleeve  21  through a counter bore  28  and an outlet duct  30  leading to a sump or sink at atmospheric pressure (not shown). 
     The lower bore  26  is surrounded by a counter bore  26   a  that communicates with a fluid supply or inlet duct  32  through which fluid either a gas such as air, steam or a hydraulic fluid is pumped at a selected pressure, e.g., 100-400 psi during operation. The air space within sleeve  21  below the top portion of the spool  16  is vented to atmosphere through duct  16   f . The valve spool  16  has a downwardly and centrally tapered poppet valve surface  16   a  at its lower end which is yieldably biased by spring  23  in sealing engagement with the seat  16   b  while the I.C. valve  14  is fully open as shown in  FIG. 3 . 
     In the last 0.030 inch downward movement of the spool  16  when the top ring R passes and then opens the ports  21   c , momentum and spring  23  carries the spool onto seat  16   b  thereby removing all upward force on the spool. In the embodiment of  FIG. 11  there is an annular lip  70  extending upwardly from the upper edge of the seat  16   b  with a close fit to the spool side wall which seals on the side of the spool before the spool contacts seat  16   b  and before the ports  21   c  open. 
     Just below the tapered poppet valve seat  16   b  is a valve chamber  40  within the casing  11  that communicates when valve spool  16  is off its seat  16   b  between the bore  26 , the supply duct  32  and a metering duct  42 . In the metering duct  42  is a metering needle valve  44  that is yieldably urged off of its seat  46  by a compression spring  48  to enable the flow rate of fluid from the supply duct  32  and valve chamber  40  to be regulated through duct  42  into the timing control cavity  27  above the valve body  16  for controlling the seating of spool  16  as will be described below. 
     The valve stem  14   a  is slidably mounted within a standard valve guide  14   b  which extends upwardly into a commercially available rubber valve seal  13 . Above the seal  13 , the valve stem  14   a  is sealed by means of a fiber reinforced compression packing  13   a  and two O-rings  13   b . A lower portion of the valve stem  14   a  can be secured to on upper portion by screw threads  14   d  that are secured in place by means of a set screw  14   c.    
       FIGS. 1-4  show how the position of each of several control valves  44  in a multi-cylinder engine can be set simultaneously by changing the position of several camming ramps  52  (one for each cylinder) affixed to control rod  54  that is slidably mounted in support brackets  54   a  to be moved axially to any selected position by a stepper motor  56  positioned by an electronic control unit (ECU)  58  through a worm gear  53  and rack  55  on the rod  54 . The camming ramp  52  for each engine cylinder rests on the outer end of a needle  44 . As the rod  54  is moved upwardly as seen in  FIG. 2  the metering needles  44  are moved by each ramp  52  closer to their seats  46  thereby reducing the flow rate of fluid past valve  44 . Movement of rod  54  in the opposite direction has the reverse effect. 
     It is preferred that the cross-sectional area of the upper end of the spool  16  is somewhat larger than the area at the lower end of the spool, in this case for example, 2.25 inches diameter at the top and 2 inch diameter at the lower end of the spool  16 . With this diameter ratio the force applied to the top of spool  16  due to compression at the moment the valve  16  is first raised to its uppermost will not exceed the force applied by supply pressure to the lower end of the spool  16 . The pressure will then be able to rise in the timing chamber  27  responsive to the controlled flow rate through the valve  44  until a much greater down force and spring  23  slams the valve  16  to its seated position of  FIG. 3  at the time selected. 
     To correctly time the I.C. valve  14 , the ECU  58  must have the time of its opening and closing.  FIGS. 3 and 4  show one example in this case how light from a source at  51  introduced through part of a fiber optic bundle  72  can be reflected or not reflected based on the position of a marker  51   a . If reflected light returns through a second portion of the fiber optic bundle  72  to a sensor at  51  it indicates the instant valve  14  opens and closes. 
     Operation with Compressed Air or Steam 
     The operation of the apparatus for controlling I.C. valve timing when using compressed air or other vapor, gas as a working fluid will now be described. Before starting, the spring  23  holds valve spool  16  closed and I.C. valve open. A current pulse from the ECU  58  at the time selected energizes the electromagnet  19  raising the armature  12 , first taking up tappet clearance to bring its upper surface into contact with the lower surface of the stop  17 . The armature then rises through the air gap, typically about 0.010 to 0.025 inch until the armature is seated on the pole face A-B of the electromagnet  19  while imparting upward movement to the valve stein and both valve  14  and spool  16 . Because the armature is little more than a microscopic distance from the electromagnet  19 , it can be seen that the force applied by the electromagnet  19  can approach the maximum that its magnetic force field is capable of achieving, i.e., a force that is not significantly diminished by having been produced in an area of reduced magnetic flux density. This helps maximize both the magnetic traction force and cycling rates. 
     While the piston  16  is seated, there is no axial thrust applied to it regardless of the pressure of the compressed air supply in duct  32 . However, as the valve spool  16  is lifted off its seat  16   b  slightly by the armature  18 , compressed air or other fluid is injected past the valve seat  16   b  below the valve spool forcing the spool upwardly closing the I.C. engine valve  14  as well as closing the outlet vent ports  21   c  that lead through duct  30  to the sump. In this way the upward fluid pressure applied to the valve spool  16  from below makes it possible to eliminate the heavy spring commonly used in I.C. engines. As the valve  16  rises off its seat the valve stem  14   a  slides upwardly through the opening  18   a  in the armature and the stop  17  moves up into the pocket  19   b.    
     With spool  16  off its seat, air flows past the control needle  44  through duct  42  into the control cavity  27 . When the pressure above valve spool  16  exceeds the force of spring  23  and the upward force from below the valve, the spool  16  is propelled onto its seat  16   b  at the time established by the setting of needle  44  thereby opening the I.C. valve at the time selected by ECU  58 . The larger ID on the top of the spool in the sleeve  21  makes it possible for the same fluid supply pressure at both ends of spool  16  to create a greater downward force on the valve body so as to greatly exceed the upward force from below thereby driving open the I.C. valve. The closer metering valve  44  is moved to its seat  46 , the longer is the time interval required for the pressure in cavity  27  to exceed upward fluid pressure on valve  16 . When metering valve  44  is opened more, the time interval is shortened. 
     Operation with Liquid Hydraulic Fluid 
     Operation is generally as described above. However, to prevent a relatively static fluid condition in the duet  42  past the control needle  44 , a commercial hydraulic accumulator  60  preferably of the gas pressurized type having a sealed chamber  60   a  can be coupled to duct  42  between needle valve  44  and control chamber  27  through a port  61 . During operation when magnet  19  raises the armature  18  causing pressurized hydraulic fluid to be injected below valve body, the I.C. valve  14  is almost instantly driven onto its seat  12   a  and the outlet ports  21   c  which lead to the sump at atmospheric pressure are closed. Pressurized hydraulic liquid then flowing past needle  44  in duct  24  charges the accumulator  60  to the supply pressure, at a rate regulated by setting of the control needle  44 . When the rising pressure in accumulator  60  and timing control chamber  27  overcomes the hydraulic lifting force on valve body, the spool  16  is forced down against its seat  16   b  moving the I.C. valve  14  to its fully open position at the selected time. If the ECU  58  and the control rod  54  move each valve  44  closer to its seat  46 , the timing of the opening of I.C. valve  14  is phased later in the cycle. When each valve  44  is raised further off its seat, each I.C. valve  14  is opened earlier in the cycle. 
     Refer now to  FIG. 9 . As explained above, the time interval for valve  16  to remain open is controlled by a needle valve  44  which regulates the flow of a fluid from a high pressure source, e.g., 100 psi to a control chamber  27  above valve  16 . The graph of  FIG. 9  shows how the time required for pressurized air in this case to reach 100 psi from 14.7 psig varies with the size of an adjustable metering opening. It will be seen that the opening of valve  44  can accurately control the time for chamber  27  to exceed the force produced by the supply pressure on the lower surface of valve  16  whereby the downward force caused by air pressure on the top of spool  16  and the spring  23  will then drive valve spool  16  closed onto its seat  16   b  opening I.C. valve  14  at a selected time. 
       FIG. 10  shows the results of several test runs carried out using compressed air at 130 psi with a control valve test article similar to spool  16  but having an OD of 2.5 inches throughout. The size of the timing needle and relative size of the control chamber  27  above the spool were proportioned to have the spool open and close during a fraction of a rotation of the crank. The graph demonstrates how the time in each cycle required for the control valve to be lowered to the closed position was accurately controlled during the test by a needle valve setting. 
     EXAMPLE 
     A test article comprising a laminated electromagnetic  19  and armature  18  measuring 2.5×3×1 inch with a stator winding of 40 turns and an armature air gap set at 0.010 inch when supplied with 12.4 amperes DC will develop an indicated traction force on the armature of about 150 lbs. When using a return spring  23  of 30 lbs., the net upward force on the armature therefore is 120 lbs. 
     When running at 7200 RPM, the duration of each cycle of two revolutions in a four-stroke engine would be 60 cycles per second or 16.7 ms. per cycle. A typical exhaust valve is open about 250/720 of each 16.7 ms. cycle or 5.8 ms. and closed for 10.9 ms. 
     A cycling test was conducted using a snubber type network circuit of known construction in which the test article having an air gap of 0.010 inch drew 12.4 amps at 60 hertz. Conditions were as follows during the test: Stator winding 0.049 ohms at an inductance of 0.003 heneries, sensing resistor 0.113 ohms at 1.4 volts and current measured at 12.4 amperes. An oscilloscope indicated the time period required to build up flux in the magnet was 3.5 ms. 
     The remaining time indicated to move the armature and the entire valve train weighing about 0.5 lb. up 0.375 inches by applying a pressure of 100 psi to control valve  16  having an OD at its lower end of 2 inches to a fully closed position is 1.7 ms. resulting in a total control valve opening time of 5.2 ms. (3.5+1.7 ms) out of the complete cycle lasting 16.7 ms. at 7200 RPM. During operation the closing of the I.C. valve can then be detected by the sensor  51  so that the ECU  58  has information to then advance or retard the actuation pulse to the electromagnet  19  such that closing of the I.C. valve occurs at the desired point in the cycle. When cycled at 120 Hz for over an hour, the total electromagnet energy loss was 15 watts which was within acceptable limits. 
     The terms “up”, “down”, “raise”, “lower” and the like are used relative to other parts of the device not to orientation relative to the earth. 
     Many variations of the invention within the scope of the foregoing specification will apparent to those skilled in the art once the principles described herein are read and understood.