Intake valve structure and method of manufacture

Abstract

an intake vallve for an internal combustion engine is disclosed. The method comprises providing a valve base comprising an elongated stem and an enlarged portion. A floating peripheral ring is provided and is positioned on the valve base. The floating peripheral ring is locked into place with an annular locking component. The locking component defines a range of motion of the floating peripheral ring with respect to the valve base.

Description

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]The present invention relates to intake valves for internal combustion engines. More particularly, this invention pertains to an intake valve that includes a floating valve seat, methods of manufacture of the intake valve and structure of the intake valve resulting from the method of manufacture.

[0003]2. Description of the Prior Art

[0004]Among the most critical elements of an internal combustion engine is the valves that regulate the gas flow into and out of the combustion chambers. Each chamber houses one reciprocating piston. Thus, for example, an eight cylinder engine has eight pistons requiring the careful regulation of sixteen valves (assuming two valves per cylinder). Some engines may include more valves per chamber.

[0005]The output of the engine consists of rotation of a crankshaft. This motion is distributed to the wheels by means of a differential engaged to an axle. Rotation of the crankshaft is produced through successive, phased inputs of angular motion via connecting rods pivotally engaged at one end to pistons, and at the other, to rod journals which are often offset from the main journals that lie along the axis of rotation of the crankshaft. The application of successive, phased forces to the offset journals results in crankshaft rotation.

[0006]The axis of rotation of the crankshaft is aligned with that of a drive shaft that can be engaged and disengaged from the crankshaft by means of a clutch. The output of the drive shaft is, in turn, employed to drive the wheels of the vehicle through the differential.

[0007]Thus, an internal combustion engine translates the reciprocating motions of the pistons into rotation of a shaft. The generation of the reciprocating movements of the pistons is accomplished through the well-understood four-stroke process of internal combustion known as the Otto cycle. The four elements of this process include an "intake stroke" during which a mixture of air and fuel is received at the top of the combustion chamber (i.e. above the piston) from a carburetor or fuel injectors. The piston travels downwardly (pulled by the rotating crankshaft via the connecting rod), creating a vacuum that draws in the air-fuel mixture. After the intake stroke, the portion of the combustion chamber above the piston is sealed by the closure of an intake valve and a "compression stroke" is commenced during which the connecting rod pushes the piston upwardly, compressing the air-fuel mixture. Once the compression stroke has been completed, a high-voltage spark is emitted by a spark plug, igniting the air-fuel mixture within the sealed combustion chamber in an Otto cycle. Other cycles exist such as a diesel cycle that does not include the step of ignition with a spark. The resulting combustion of the mixture causes a sudden, yet controlled expansion of gaseous volume, generating a force that acts downwardly upon the top of the piston during a "power stroke". This drives the piston down to impart rotation to the crankshaft. The amount of angular motion imparted is, in part, dependent upon the number of engine cylinders. Once this motion has been completed, the gases within the combustion chamber are vented during an "exhaust stroke" as the piston is again driven upwardly within the cylinder by the rotation of the crankshaft and the exhaust valve that regulates the passage of gases through an exhaust port is opened. Another four-stroke cycle then begins with another intake stroke in which air-fuel mixture is admitted through a reopened intake valve as the exhaust valve is closing. At a typical freeway engine speed of 2200 r.p.m., the entire four-stroke process is completed at a rate of eighteen times per second in each cylinder.

[0008]Intake and exhaust ports communicate with the portion of the cylinder that lies above top dead center of the piston (i.e., the combustion chamber). The intake and exhaust valves seal the head ports. The motions of the valves are derived from the crankshaft of the engine through a valve train linkage that includes the valve itself.

[0009]The valves include elongated stems and terminate in generally-circular broadened heads that include an angled seat cut to mate with a seat formed in the cylinder head. The cylinder head seats and poppet-type valves interact whereby the combustion chamber is opened to communicate with the intake and/or exhaust ports by the action of the valve train pushing down on the valves and then closed by a spring, or by other methods which are side components of the valve train. The spring returns the valve (stem protruding from the port of the cylinder head to the rocker assembly side of the head) until its enlarged circular head abuts the circular head seat adjacent the top of the combustion chamber. A seal is formed between the circumferential seat of the valve and the circular seat of the cylinder head. Both faces are frustoconical. Conversely, an intake valve admits a gaseous mixture when driven downwardly (into the combustion chamber) to disengage the valve face from the head seat located in the combustion chamber of the engine head.

[0010]The cam of the valve linkage that defines the relationship between rotation of the crankshaft (and, thus travel of the piston within the cylinder) and the opening and closing of the intake and exhaust valves is of static design. Since the cam possesses a static, fixed shape, the relative timing of the opening and closing of the valves with respect to the travel of the piston within its cylinder is correspondingly limited or static.

[0011]The mass and resulting momentum and inertia, of the valve train constrains the ability of the engine to operate in an idealized manner insofar as the coordination of valve operation and piston movements within the combustion chamber. For example, a typical profile of the intake stroke might consist of the cam gear gradually opening the inlet valve by one-eighth inch upon the piston having traveled downwardly by two inches, then increasing to one quarter inch when piston travel has increased to three inches, then continuing to be held open by one-quarter inch during the fourth inch of travel of the piston. The valve might then begin to close during the interval between the fourth and fifth or final inches of downward travel of the piston. This would occur in anticipation of its imminent closure for the subsequent compression stroke.

[0012]Such "preparation" of the valve for closure during the transition from the intake to the compression stroke, built into the shape of the cam, is an acknowledgment of the inability of the valve train to reverse direction instantaneously in view of its mass. The non-idealized operation of the valve with respect to the movement of the piston within the combustion chamber has the effect of either forcing some amount of the fresh air-fuel mixture out of the chamber through the intake port (in the event that the point of closure of the intake valve occurs after the direction of the piston has reversed) or the admission of a less-than-maximum amount of air-fuel mixture into the chamber (in the event that the point of closure occurs somewhat prior to completion of downward travel of the piston). In either event, the torque generated by the engine is reduced below that theoretically possible with a valve linkage of zero mass.

[0013]An additional practical limitation upon valve operation is crankshaft rotation rate (in r.p.m.). Practical cam design requires more gradual transitions between valve openings and closings at a high r.p.m. engine output to prevent risk of valve train element disengagements. The resultant gradual reversals of valve direction further reduce the torque that may be generated by an internal combustion engine through reduction and/or contamination of intake of fresh air-fuel mixture and loss of compression.

[0014]Like issues pertain to the transition from the exhaust to the intake strokes. The exhaust valve, also located at the top of the combustion chamber with respect to the intake valve, undergoes closure during this transition. In the event that the intake valve, making a transition from a closed to an open attitude as the piston rises to the top of its travel, opens "early" (before the exhaust valve has closed and the piston has reached the top of the chamber, a condition known as "overlap"), exhaust gases can escape from the chamber through the slightly open intake valve and into the intake port (a condition known as "reversion"). This will contaminate the fresh air-fuel mixture admitted during the intake stroke. Conversely, should the intake valve open "late" (after the exhaust valve has closed and the piston has already begun downward travel), less than the theoretically-possible maximum amount of air-fuel mixture will enter the cylinder during the intake stroke. In either case, the torque generated during the following power stroke is ultimately reduced.

[0015]One approach to mitigating the problem of static valve timing is embodied in a device marketed under the trademark SMART VALVE by Acro-Tech, Inc. which is described in an article entitled "Variable Valve Timing", American Iron Magazine (September 2000) at page 135. Such device comprises an intake valve, suitable for retrofitting to a four cycle engine that is characterized by a two-part valve head structure. Such structure consists of a valve head base and a surrounding peripheral ring. The valve head base comprises an otherwise-conventional valve head machined to accommodate the peripheral ring in slidable, locking relationship. The precise vertical position of the peripheral ring is responsive to gas pressure within the combustion chamber. When actuated by gas pressure to travel upwardly either at the beginning of the compression stroke or at the transition from exhaust stroke to intake stroke, the peripheral ring, in combination with the valve head base, seals the intake port prior to the time otherwise dictated by the fixed shape of the cam. This results in a type of variable valve timing in which loss or contamination of air-fuel mixture and/or compression loss is minimized and engine torque is thereby increased.

[0016]Another approach is described in U.S. Pat. No. 6,659,059 (Huff). That patent describes a variable displacement valve seat assembly effective for prevention of opposite directional flow of gases to or from the combustion chamber through the intake and exhaust ports of an internal combustion engine, said valve seat assembly comprising: a) a base seat means designed to releasably seal an annular ring seat, said base seat means including a base seat mating surface, b) an annular ring seat means, including both an inboard and outboard seat mating surface, said inboard seat mating surface designed to correspond with said base seat mating surface, said outboard mating surface designed to releasably seal an intake or exhaust port within the combustion chamber of an internal combustion engine, c) a locked engagement means designed to lock the said annular ring seat means into releasably sealable engagement with said base seat means, said locked engagement means designed to allow controlled linear coaxial displacement of said annular ring seat means to a predetermined limit.

[0017]While offering a useful concept, the precise design of the device described above is subject to a number of weaknesses. The design permits a continuous escape of gases through actuation port holes when the ring is in the lifted position due to the location of the lock mechanism. In addition, the location of the locking mechanism for slidably securing the peripheral ring to the valve head base (in the region of the margin of the valve head) limits the ability of a designer to increase the vertical travel of the peripheral ring without increasing the mass of the valve head and ring. Finally, the positioning of the locking mechanism subjects potential areas of weakness to maximum stressing and permits the cocking of the peripheral ring with respect to the axis of the valve, permitting the peripheral ring's locking lip to drag against the valve head margin area, increasing wear and failure rates. The mating areas will allow excessive use to hammer the peripheral ring below its desired seating position. The design also incorporates knife edges on the ring that are susceptible to abuse. In addition, sharp inner corners become fracture points, causing failure.

[0018]U.S. Pat. No. 6,598,577 (Marino, the present inventor) addresses many of these structural problems. In this design, an intake valve includes a floating seat for attaining variable valve timing. A valve base is provided. The valve base includes an elongated stem, an enlarged portion. In one embodiment, a connecting radius is positioned between the valve stem and the enlarged portion. The enlarged portion includes a region for accommodating a peripheral ring in vertically-actuatable relationship. The region of the enlarged portion for accommodating the peripheral ring includes a vertical locking portion and a frustoconical outer seat that mates with an inner frustoconical seat of the peripheral ring. A port may be arranged to vent gases at an upwardly-sloping portion of the bottom of the interior of the peripheral ring, thereby preventing instantaneous gas seepage while the peripheral ring is elevated. The vertical locking portion is positioned at the inner circumference of the peripheral ring to permit adjustment of peripheral ring travel without adding to the mass of the valve head.

[0019]The manufacture of the device in U.S. Pat. No. 6,598,577, although enabled by the teachings, proved to be complex in commercial quantities. It has therefore become necessary to develop a manufacturing process that can be used for larger volume and more precise manufacture of the valve head of U.S. Pat. No. 6,598,577.

SUMMARY OF THE INVENTION

[0020]The invention comprises an intake valve for an internal combustion engine and a method of manufacturing that intake valve. The valve comprises a valve base, a peripheral ring and an annular locking component. The valve base includes an elongated valve stem and an integrally formed enlarged portion. A connecting radius in one embodiment joins the valve stem and the enlarged portion. The enlarged portion of the valve base is circular in shape at its base and decreases in outer diameter until the outer surface intersects the outer surface of the elongated valve stem. A floating peripheral ring is provided with an inner frustoconical seat that mates to an exterior frustoconical seat on the valve base. Both the enlarged portion and the floating peripheral ring define the valve head. The peripheral ring has a central axis that is co-axial with a central axis of the valve stem. This ring reciprocates in a direction parallel to the central axis of the valve stem and the central axis of the ring.

[0021]The peripheral ring also includes an outer seat that in a preferred embodiment is frustoconical in shape. The outer seat mates to the cylinder head seat.

[0022]The peripheral ring also includes an inner cylindrical wall.

[0023]The cylindrical wall is parallel to a central axis of the valve stem. The region of the valve base for receiving the peripheral ring includes an outer cylindrical wall substantially parallel to the inner cylindrical wall of the peripheral ring and in opposed relationship to the inner cylindrical wall of the peripheral ring. The inner cylindrical wall of the peripheral ring has an inwardly-directed flange. An annular locking component is provided with an outwardly directed flange. This locking component is affixed either directly or indirectly to the valve base and locks the peripheral ring onto the valve base. The locking component may be permanently affixed such as by means of welding or removably affixed such as by means of a threaded connection. In another embodiment, the locking component is affixed to the valve stem. The peripheral ring may travel in a direction parallel to a central axis of the valve stem until coming into contact with an outwardly directed flange of the locking component. The total amount of travel of the peripheral ring is limited by contact of the outwardly directed flange of the locking component and the inwardly directed flange of the peripheral ring. The locking component together with the inwardly-directed flange of the peripheral ring defines a locking system for the overall valve.

[0024]According to a first embodiment of the invention, the section of the valve that includes the outwardly directed flange is fabricated separately from the remainder of the valve base. After the peripheral ring is installed on the valve base, the annular locking component comprising this outwardly directed flange is installed and affixed to the valve base, such that the ring cannot be removed after fabrication. In another embodiment, the annular locking component is removably attached. When the locking component is removably attached, it is important that the component is affixed in a manner that will not permit disengagement during operation. In one embodiment, the locking component is ring-shaped and is welded to the valve base. In another embodiment, the locking component is a ring with a threaded female connection that threads to male threads located on an exterior surface of the enlarged portion. In other embodiments, the locking mechanism is located on the connecting radius or on the valve stem. A preferred location for installing the annular locking element is on the enlarged portion of the valve base. One preferred component part comprises a continuous annular locking component and one method of fabrication comprises welding the locking component to the valve base to prevent the peripheral ring from disengaging from the valve base.

[0025]Another embodiment of the invention includes a locking component having an outwardly directed flange that is integrally formed with the valve base. After the peripheral ring is positioned over the valve base, excess material (such as a bead of metal on an upper surface of the enlarged portion is pressed outwardly away from a central axis of the valve stem to form the outwardly directed flange as part of the fabrication process.

[0026]The invention provides an internal combustion engine that includes an intake valve in accordance with the embodiment described above. In operation, the outer seat of the floating peripheral ring comes into contact with the cylinder head seat in a first position and the inner seat of the floating peripheral ring comes into contact with the seat of the valve base in a second position.

[0027]The process may also be described as providing a valve base, comprising an elongated valve stem and an enlarged portion located at one end and integrally formed with the elongated valve stem. The valve base may also include a connecting radius between the valve stem and the enlarged portion. The enlarged portion has an inner seating surface that mates with an inner seat of a peripheral ring;

[0028]providing a floating peripheral ring with an outer valve seat for seating with a cylinder head seat, an inner seat for seating with the inner seating surface of the enlarged portion, and having an inwardly directed locking flange;

[0029]providing an annular locking component having an outwardly directed flange for locking the floating peripheral ring to the valve base;

[0030]positioning the floating peripheral ring onto the enlarged portion so that the floating peripheral ring is movable with respect to the valve base;

[0031]positioning the annular locking component over the stem and floating peripheral ring;

[0032]affixing the annular locking component to the valve base to define a range of motion for the floating peripheral ring with respect to the valve base; and

[0033]thereby slidably locking said peripheral ring to said enlarged portion by the outwardly directed flange of the locking component.

[0034]The preceding and other features of this invention will become further apparent from the detailed description that follows. Such description is accompanied by a set of drawing figures. Numerals of the drawing figures, corresponding to those of the written description, point out the features of the invention with like numerals referring to like features throughout both the written description and the drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035]FIG. 1 is an idealized partial side-sectional view in elevation of the upper portion (above the piston) of a combustion chamber of an internal combustion engine in accordance with the prior art;

[0036]FIGS. 2(a) and 2(b) are side elevational views of an intake valve of the floating valve seat type in accordance with the prior art for illustrating the principle of variable valve timing;

[0037]FIG. 3 is a detailed partial sectional view of an intake valve taken at line 3 of FIG. 2(a);

[0038]FIG. 4 is a detailed partial sectional view of an intake valve in accordance with the invention corresponding to the view of the prior art valve of the previous figure.

[0039]FIG. 5 shows a cross sectional view of one embodiment of an intake valve of the present invention.

[0040]FIG. 6 shows an alternative embodiment of an intake valve according to technology of the invention described herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0041]FIG. 1 is a schematic partial cross-sectional view in elevation of the upper portion (above the piston 12) of a combustion chamber 10 of an internal combustion engine in accordance with the prior art single-piece valve structures. The chamber includes conventional intake 14 and exhaust valves 16 of the poppet type mounted for regulating flow of gases into and out of the combustion chamber in accordance with the operational principles of the well-known four stroke Otto cycle, or diesel cycle, described above. The operation of the engine involves the coordination of gas flow through the intake and exhaust ports 18 and 20 by means of opening and closing of the intake and exhaust valves 14 and 16 respectively and timed with the up-and-down movements of the piston 12 within the combustion chamber or cylinder.

[0042]As illustrated, the structures of the prior art intake and exhaust valves 14 and 16 are similar in overall shape. However, intake and exhaust valves need not be of the same size or present in the same numbers in a combustion chamber. For example, a combustion chamber may have more intake valves than exhaust valves or more exhaust valves than intake valves. For purposes of illustration, one intake and one exhaust valve are shown, and both valves are of the same size. Referring to the intake valve 14, it includes an elongated stem 22 that is integral with and terminates in an enlarged head portion 26. The head portion 26 is shaped with an inclined valve seat 28 and a cylindrical peripheral margin 30.

[0043]The inclined valve seat 28 is designed to mate with a similarly-inclined cylinder head seat 32 positioned at the transition of the intake port 18 to the combustion chamber 10. (Similarly, the exhaust valve 16 includes an inclined valve seat 36 that mates with a cylinder head seat 38 at the transition between the combustion chamber and the exhaust port 20.

[0044]FIG. 1 illustrates the intake stroke of the combustion chamber in which the intake valve 14 has been forced downwardly to disengage from the head seat 32, thereby opening the intake port 18, by the action of a valve linkage (not illustrated, discussed above) to which it is coupled. When the exhaust valve 16 has been seated, the exhaust port 20 is closed by the action of a spring (not illustrated).

[0045]The action of the valve linkage that opens the intake valve 14 to admit air-fuel mixture for the intake stroke is mechanically coupled to the mechanism that drives the piston 12. Upon release of downward force from the valve linkage, the intake valve 14 will be drawn into the closed position by the action of a valve spring or alternative mechanism (not illustrated) just as the exhaust valve 16 has been closed.

[0046]The problems relating to static valve timing deriving from a cam of fixed shape have been discussed above and are addressed to some extent by the two-part floating seat valve apparatus of Acro-Tech, Inc. described in the previously-referenced article. The principle of operation of the prior art floating seat valve for achieving variable valve timing is illustrated in FIGS. 2(a) and 2(b), showing side elevation views of an intake valve of the floating seat type in accordance with the prior art. In contrast to the design of a conventional one-piece intake valve 14 of the poppet type as illustrated in FIG. 1, the intake valve 42 of FIGS. 2(a) and 2(b) includes a two-part valve 42. The valve 42 includes a valve base including an elongated stem 48 and an enlarged portion 46 that is integrally formed with an elongated stem 48. The valve 44 also includes a moveable peripheral ring 50 that is slidably engaged to the enlarged portion 46. The means for slidably coupling the enlarged portion 46 to the peripheral ring 50 will be disclosed and discussed in detail below.

[0047]Various portions of the enlarged portion 46 and the peripheral ring 50 correspond generally to regions of the conventional intake valve of FIG. 1 when fully mated in the closed position shown in FIG. 2(a). Thus an outer seat 54 is formed on the peripheral ring 50 and that outer seat mates with one of the cylinder head seats 32, 38.

[0048]As shown in FIG. 3, the peripheral ring 50 has an interior seat 70 that mates with an inner seat 72 of the enlarged portion 46 of the valve base.

[0049]FIG. 2(b) shows valve 42 in an open position. That is, the interior seat 70 of the ring 50 is spaced apart from the inner seat 72 of the enlarged portion 46. When the ring 50 is in this open position, a portion of an outer cylindrical surface 58, as shown in FIG. 3 is exposed.

[0050]Referring back to FIG. 1 and inserting the floating seat design, it will be appreciated that the ability of the peripheral ring 50 that carries the outer valve seat 54 to elevate above a portion of the enlarged portion 46, which is integral with the valve stem 48, enables the valve 42 to seal the intake port 18 by mating the outer valve seat 54 with the head seat 32 prior to the mating of the inner seat 72 of the enlarged portion 46 to the inner seat 70 of the ring 50 (shown in FIG. 3). It is this ability of the relatively-low mass peripheral ring to seal the intake port 18 prior to the time that the elements of the valve linkage (of much greater mass) are capable of, or timed to accomplish such sealing relationship that provides the variable valve timing that overcomes the delays inherent in static valve timing described above.

[0051]As mentioned earlier, such momentum and inertia-mandated delays cause, for example, the opening of the intake valve prior to the complete closure of the exhaust valve on the exhaust stroke (resulting in the contamination of the air-fuel mixture with some exhaust gas content, referred to as "overlapping"). The ability of the peripheral ring 50 to seal an intake port while the intake valve 42 is moving off of its seat and before the exhaust stroke has ended enables the period of overlap to be minimized and/or eliminated. The elevated position of the peripheral ring 50 is achieved in response to the generation of gas pressure within the combustion chamber 10 at the ending of the exhaust stroke during the period of overlap and at the beginning of the compression stroke. The mechanism for slidably securing the peripheral ring 50 to the enlarged portion 46 so that the peripheral-ring 50 will react to gas pressure within the combustion chamber 10 and the ports 18 and 20 will become apparent from a more detailed discussion of FIG. 3.

[0052]FIG. 3 shows a detailed partial cross-sectional view of an intake valve with variable valve timing in accordance with the prior art taken along line 2-2 of FIG. 2(a).

[0053]As can be seen in FIG. 3, the prior art two-piece peripheral ring 50 is slidably secured to the enlarged portion 46 of the valve base by means of a locking flange 60. The locking flange 60 protrudes inwardly from the lower edge 62 of the peripheral ring 50. An outwardly extending annular flange 64 on an outer surface of the enlarged portion 46 is of a size and shape sufficient to permit installation of the peripheral ring 50 over the enlarged portion 46 by means of a press fit.

[0054]A port 66 (one of an array that is preferably symmetrically extending from a dished portion 68 of the combustion valve face of the enlarged portion 46 to the inner seat 72 of the enlarged portion 46) is provided for venting gases under high pressure from within the combustion chamber 10 during the compression stroke or valve overlap to thereby lift the peripheral ring 50 to the position or attitude illustrated in FIG. 2(b) whereby the valve seat 54 is elevated to be seated against the head seat 32. The ring 50 closes the intake port 18 prior to the time that the valve base arrives. The valve base is then moved into position by means of the valve linkage connected to the valve stem, including a cam of fixed shape to seal this port. The rapid sealing of the intake port 18 provides additional flexibility in the design of the intake valve linkage, the exhaust valve timing and the coordination of the travel of the piston 12 within the combustion chamber with the valve timing. As a result, horsepower is increased (as air-fuel mixture can be admitted during a greater portion of the intake stroke and will suffer less contamination and reversion due to the decrease or elimination of overlap) and greater r.p.m. is possible for a given output due to lowered stressing of the valve linkage.

[0055]While the prior art intake valve with a floating valve seat 54 is machined onto a peripheral ring 50 as shown in FIG. 3 offers significant advantages of variable valve timing over the conventional integral intake valve, the prior art design is subject to a number of weaknesses. These result, in large measure from a two-part structure that lacks the durability needed to operate with great precision both repetitively and at high speeds and loads within a very hostile environment. Furthermore, the prior art valve design has operational disadvantages. For example, the upward thrust of high pressure gases through the port 66 allows some seepage of exhaust gases or intake charge upward and into the intake port 18 during the time the peripheral ring 50 is in its lifted position to seal the port 18 but before the inner seat 72 of the enlarged portion 46 seats against inner seat 70 of peripheral ring 50. Such seepage occurs within a flow path momentarily existing between the upper inner surface 70 of the peripheral ring 50 and the outer surface 72 of the region of the enlarged portion 46 for accommodating the peripheral ring 50.

[0056]Additionally, the design of the prior art valve of FIG. 3 offers limited flexibility with regard to the possible length of vertical travel of the peripheral ring 50. Such vertical travel is defined and limited by the vertical distance between the inwardly-directed flange 60 and the outwardly-directed flange 64. To increase this length, both the outer margin 56 of the ring 50 and the inner margin 58, must be lengthened. This may result in significantly increasing the mass of the intake valve. As a result, the valve train becomes more difficult to control. The clearances between intake and exhaust valves, intake valve and the piston and the momentum from the extra weight are all difficult to control. In addition, increased valve mass limits engine r.p.m. and reduces engine life. Finally, the prior art design of FIG. 3 allows flexion of the outer ring 50 whereby the inner flange 60 of the ring 50 can drag against the inner margin 58 of the valve head base, causing the ring 50 to become cocked. Such cocking of the peripheral ring 50 may lead to the rapid failure of ring 50 by causing stress fractures in the corner 71a. The loss of effective functioning of the ring 50 can negate the increased power advantages that follow from variable valve timing and ruin the motor.

[0057]FIG. 4 is a detailed partial sectional view, corresponding to the preceding view of the prior art valve, capable of being fabricated according to one of the methods of the present invention. The valve of FIG. 4 operates generally in accordance with the principles of operation of the valve of FIGS. 2(a), 2(b) and 3. However, it offers a number of design features that address shortcomings of an intake valve with a floating valve seat in accordance with the prior art.

[0058]As in the case of the above-described intake valve with floating valve seat, the intake valve fabricated according to methods of the present invention relies upon the principle of a cooperative enlarged portion 74 and peripheral ring 76, forming valve head 71. The peripheral ring 76 is arranged within a region of the enlarged portion 74 to be slidable along a central axis (not shown) of the enlarged portion 74, which is co-axial with a central axis of the valve stem (not shown) in response to pressure within the combustion chamber upon initiation of the compression stroke and completion of the exhaust stroke to provide the advantages of variable valve timing. As before, ports, such as the port 78 extend from the combustion face dish 81a of the combustion face 81 through to an angled surface 84 of the enlarged portion 74 to admit the pressurized gases that thrusts the peripheral ring 76 upwardly to sealing relationship with a cylinder head seat to seal the intake port in a way that cannot be achieved by static valve timing as discussed with reference to FIG. 1. As an aside, it is both theoretically and actually possible to design a valve with a floating valve seat without employing the ports 66 and 78 of the device of the prior and present figures. In such cases, actuation of the peripheral rings 50 and 76 will be dependent upon the force of pressurized gases against the annular lower edges 62, 79 of the peripheral rings 50 and 76 respectively.

[0059]The peripheral ring 76 of the intake valve of the present invention differs significantly from that of the prior figure. The ring 76 is slidably locked to the enlarged portion 74 of the valve head 71 by the interaction of an inwardly-directed annular flange 80 of the ring 76 with an outwardly-directed flange 82 of the enlarged portion 74. However, in contrast to the prior art device, such locking mechanism does not coincide the margins 56 and 58 of the prior art intake valve. Instead, the locking mechanism is spaced apart from the margins 56 and 58 and located closer to a central valve stem axis. That is, the locking mechanism it is not located at the outer periphery of the enlarged portion 74. As a result, it is possible to lengthen the travel of the peripheral ring 76 by increasing distance "d" as shown in FIG. 4 without increasing the mass of the valve or elongating the margins. The depth "d" of the region of the enlarged portion 74 of the valve head 71 for receiving the ring 76 might be increased (along with a corresponding increase in the length "h" of the peripheral ring 76). By providing this capability, the design of the valve timing can be varied without incurring the complications that arise when the mass of the valve is increased.

[0060]In addition, the improved positioning of the locking mechanism above the opening of the port(s)78 assures a positive seal preventing the escape of gases through the port holes 78 into an intake port when the ring 76 is in the lifted position. That is, both the inwardly-directed annular flange 80 and the outwardly-directed flange 82, which comprise the locking mechanism of the valve of the invention, project into the path of pressurized gases escaping from the combustion chamber to lift the peripheral ring 76, and form a seal. This blocks the possible leakage of such gases into the intake port once the peripheral ring 76 has sealed the port. In contrast, the locking mechanism of the device of FIG. 3 lies below the upper end of the port 66, leaving no like structures to project into the leakage path for escaping pressurized gases once the peripheral ring 50 has been lifted to seal an intake port. By eliminating the possibility of such leakage, the intake valve of the invention permits an internal combustion engine to attain greater torque and horsepower than one equipped with intake-valves with a floating valve seat in accordance with the prior art.

[0061]The outer valve seat 90 of the peripheral ring 76 in accordance with the invention is opposed by the inner seat 92. This inner seat 92 in one embodiment is frustoconical and mates with an inner seat 94 of the enlarged portion 74 of the valve head 71. This assures that the substantial force of impact between the inner seat 92 of seated peripheral ring 76 and the inner seat 94 of the enlarged portion 74 of valve head 71 for receiving the peripheral ring 76 upon contact does not occur at a stress point of the design. This is to be contrasted with the prior art design of the preceding figures in which a vertical margin 56 of the peripheral ring 50 is joined to an upper portion of the peripheral ring 50 defined in part by the valve seat 70 in region 71a adjacent the outwardly-directed annular flange 64 of the enlarged portion 46. The peripheral ring 50 can fail in area 71a, or the outwardly projecting flange 64 can fail, or both. Such a combination risks the imposition of substantial force within a weak area. With each valve closure, valve and seat life is limited through cocking or breakage of the peripheral ring 50. The mating surfaces of the peripheral ring 76 and the enlarged portion 74, discussed above, assure that the peripheral ring 76 will always return to an uncocked attitude and a proper seated height as illustrated in FIG. 4, and completely avoids the problems associated with cocking. Cocking does not always result in failure. Cocking of the ring can self re-align. But it can also cause stress due to binding in critical areas that result in breakage or wear.

[0062]The invention allows further weight reductions and various valve head shapes to be employed for clearance and gas flow designs in the area otherwise occupied by the inner and outer margins 58 and 56 in FIG. 3.

[0063]Thus it is seen that the present invention provides an intake valve of the floating valve seat type that provides the advantages of variable valve timing. By employing intake valves in accordance with the invention in an internal combustion engine, one can realize the improved performance offered with variable valve timing without loss of horsepower due to instantaneous seepage of gases, without substantial limitations upon peripheral ring travel and attendant engine design and without the degradation of life and engine performance that follow unintended cocking of the peripheral ring relative to the enlarged portion of the valve base.

[0064]The valve as shown in FIG. 4 may be assembled by means of heating the ring 76, cooling the enlarged portion 74 and press fitting the ring 76 to the enlarged portion 74. Other fabrication techniques as described below eliminate the need for press fitting, improving the sealing ability of the locking ring and avoids the problem of breakage during press fitting. Methods of the present invention also allow the use of larger and thicker flanges. The use of larger and/or thicker flanges increases the durability of the valve.

[0065]The preferred method of the present invention for the manufacture of the intake valve comprises a method of manufacturing an intake valve for an internal combustion engine. The method is performed by first providing a valve base which is comprised of an elongated valve stem with an enlarged portion located at one end and integrally formed with the elongated valve stem. In one embodiment, a connecting radius connects the stem to the enlarged portion and is tapered. In other embodiments, the enlarged portion is connected to the elongated valve stem without a tapered radius joining the two components. The valve base has an inner seating surface.

[0066]The method includes providing a peripheral ring with an outer valve seat for seating with a cylinder head seat, an inner seat for seating with the inner seating surface of the valve base, and having an inwardly directed locking flange. The method further includes providing an annular locking component having an outwardly directed flange for locking the floating peripheral ring to the valve base.

[0067]The method includes positioning the floating peripheral ring onto the valve base so that the floating peripheral ring is movable with respect to the valve base in a direction parallel to a central axis of the ring and a central longitudinal axis of the valve base. Both central axes are co-axial. The annular locking component is positioned over the valve base and at least a portion of the floating peripheral ring. The annular locking component is locked to the valve base to define a range of motion for the floating peripheral ring with respect to the valve base, thereby retaining said peripheral ring to said valve base by the outwardly directed flange of the locking component. In a preferred embodiment, the annular locking component is positioned on the enlarged portion of the valve base. In other embodiments, the annular locking component is positioned on the connecting radius, the stem or is positioned on two or more components simultaneously.

[0068]The valve base, peripheral ring and annular locking elements may be cast, molded, machined or formed by a combination of these manufacturing processes. One or more elements may be fabricated by a different process than one or more other elements. The annular locking element is secured to an exterior surface of the enlarged portion in one embodiment. In one form of the invention, the enlarged portion includes an exterior area adapted to receive the annular locking element. The valve base may be fabricated to include this adapted exterior portion, or this exterior portion may be constructed after the initial fabrication of the valve base. One exemplary manufacturing technique to provide this area is to machine a groove or ledge defined by surfaces 120, 122 as shown in FIG. 5 into an exterior surface of the enlarged portion.

[0069]The peripheral ring has a central axis that is co-axial with a central axis of the valve base. The peripheral ring is actuatable in a direction 108 parallel to the central axis and is in a sliding contact relationship along a length 110 of the enlarged portion 102. The peripheral ring 104 is slidably locked to said enlarged portion 102 by an inwardly-directed annular flange 112 that abutts to the lock flange 114 of the annular lock element 106 when it's in an actuated state. In the illustrated embodiment, the annular locking component 106 is an annular ring with a continuous outwardly-directed flange 114.

[0070]The method thus allows for locking the floating peripheral ring to the enlarged portion after the peripheral ring is positioned over the valve base. The dimensions of the valve base are variable in accordance to engine size and design. The size, shape and location of the peripheral ring 104 and the lock element 106 and there flanges 112 and 114 are variable to fit the dimensions of the valve base.

[0071]The various components of the valve, including the valve base, the peripheral ring and the annular locking component are constructed of like materials, or unlike materials, Suitable materials of construction include metals, metal alloys, ceramics, composites, plastics, polymers and materials with various coatings. The components may or may not be coated or heat treated. Suitable coatings may provide heat resistance (ceramic coatings), reduced friction (silicon polymer, fluorinated polymer, etc.), insulating properties (ceramic or polymeric) or corrosion-resistant properties (polymeric, ceramic or titanium or non-corrosive metals). In one embodiment, the valve components are constructed of a metal alloy and are shaped by machining. One or more of the valve components may alternatively be forged, molded or extruded.

[0072]The annular locking component 106 may be adhered, fused, threaded, wedged, force fitted, welded pinned or clipped onto the valve base 100 shown in FIG. 5. In other embodiments, the locking component 106 may be fastened to the elongated valve stem or to a connecting radius located between the enlarged portion 102 and the elongated valve stem. Materials may be selected to reduce the weight of the valve, improving valve performance. In one form of the invention, the annular locking component 106 is of a lighter weight material than the materials used to construct the valve base and peripheral ring. An internal combustion engine may comprise a valve manufactured according to the method described above.

[0073]The method may be most simply described in the following generic terms, which are not intended to be limited by specific examples and figures, although FIGS. 5 and 6 are used to assist in an appreciation of the description of the present technology.

[0074]FIG. 5 shows a sectioned, cutaway view of the entire valve assembly 100 manufactured in accordance with one embodiment of the present invention. The valve assembly 100 is comprised of a stem 125, connecting radius 126, enlarged portion 102, annular lock 106, (shown fused to the enlarged portion 107) and peripheral ring 104. In other embodiments, the locking element is affixed to the radius or to the stem. The general movement of the valve base and the floating ring are in forward and aft directions. as indicated by arrow 108 which is parallel with a central axis (not shown) of each other. The annular locking component 106 in the illustrated embodiment is a continuous ring structure. In other embodiments, the locking element is discontinuous. For example, a plurality of spaced apart pins embedded partially in the enlarged portion 102 may be provided, defining a discontinuous outwardly extending flange (not shown). According to the invention, the annular locking component 106 has an outwardly directed flange 114 that is either continuous or discontinuous. In a preferred embodiment, the flange 114 is continuous and circular in shape.

[0075]Inwardly directed flange 112 of the floating ring 104 engages the flange 114 on the annular locking element 106 so that there is a maximum path of travel for the floating ring 104 of distance 100.

[0076]One concept of the technology described herein is to provide a separate annular locking component 106 as opposed to the previous disclosures of Huff and Marino that provide a continuous floating ring (such as 104) that must be snapped over a locking extension on the valve head, using force or force and heat to snap the extension of the floating ring over the lip extension of the valve head. One significant problem with this prior art methodology is the fact that the extent of the overlap (shown as distance "y" in FIG. 3) is highly limited and tends to be a very weak structural feature of the assembly. Because the overlap is limited by the ability to be able to `snap` the floating ring over the annular flange 64, the overlap distance is very limited, even when using heat expansion to increase a central diameter of the floating ring 50. Additionally, to enable the snap to occur, the thickness or length of the lips or flanges 64 and 60 are highly restricted, so that those areas of the structure can wear quickly during the stress and friction of use or even break when being applied in the prior art process.

[0077]As can be seen in FIG. 5, by applying the annular locking element 106 after overlaying the floating peripheral ring 104 on the enlarged portion 102, the thickness or height of the outwardly directed flange 114 and the inwardly directed flange 112 is not structurally limited, although it would be minimized as desired to optimize the weight/mass of the moving parts to conserve weight, energy efficiency and travel.

[0078]Therefore, one concept in the practice of the present technology includes positioning a floating ring over the enlarged portion of the valve base, the floating ring having an inwardly directed flange 112 that extends towards a side wall 118 on the enlarged portion 102, and then fixing an annular locking component 106 onto the enlarged portion 102 to provide an outwardly directed flange 114 or extension that engages the flange 112 as the floating ring moves in a direction 108 parallel with a longitudinal axis of the valve stem.

[0079]The term "fix" refers to the fact that the annular locking component 106 will not itself unintentionally disengage and will remain attached to the enlarged portion 102, as by fusion, soldering, adherence, physical engagement, heat pressing, force fitting, welding, bolts, screws, clips, threads or any other physical or chemical method of securing the locking component 106 to the enlarged portion 102. In a preferred embodiment, the annular locking component is immovable after installation. In another embodiment, the annular locking element is removable.

[0080]The present technology allows the overlap between the inwardly directed flange 112 and the outwardly directed flange 114 that is greater than that of known valve structures. In addition, the flanges 114 and 112 have thickness that are thicker than the prior art flange thicknesses. The diameter of the valve heads may be varied according to the size of the cylinder and the characteristics of the engine. The annular locking components are generally a smaller diameter than the enlarged portion of the valve base.

[0081]The valve, when removed from the cylinder, can be described as a valve having a valve base, a floating peripheral ring and an annular locking component. The valve base includes an enlarged portion integrally formed with the valve stem. In some embodiments, the valve base includes a tapered connecting radius that joins the valve stem to the enlarged portion. The floating peripheral ring floats on the enlarged portion and has a range of motion parallel to a longitudinal axis of the valve stem (which is generally positioned at an angle with respect to the vertical in a typical engine). The floating peripheral ring is locked within a range of motion defined by the annular locking component or element, which is fixed and secured to the valve base. The range of motion within which the floating peripheral ring is restrained and extends from a lowest position flush against the inner seat of the enlarged portion to an extended position (once it is seated against the cylinder head seat). The actual design of the parameters of the range of movement structured into the combination of the valve base, floating peripheral ring and the annular locking component or device will vary because of the engine sizes and the design effects desired. It is possible for the full extension of the range of motion to fall slightly short of the cylinder head seat, but this would reduce the benefits of the system. The range of motion should therefore preferably extend to a precise contact with the cylinder head seat at full extension, or still allow some additional movement that would aid in unfortunate events such as lofting a valve.

[0082]When the valve is installed in a cylinder head, the floating peripheral ring will be centrally aligned within the cylinder head structure so that essentially all top seating surfaces of the floating peripheral ring will align evenly and concentrically against the cylinder head seat at the same time.

[0083]Alternative methods of manufacture for the system of the present invention would have various separation distances between the flange 112 and the exterior side wall 118 of the enlarged portion, instead of a sliding contact 116 as shown in FIG. 5. The ring locking element 106 is shown and preferred as a continuous annular element that encircles a portion of the enlarged portion 102, but, because it is fixed to this region, the locking element may be discontinuous, such as two or more segments each fixed to the enlarged portion 102 with a separation between segments (not shown). In this respect, the term "annular" relates to the location of the locking element, not that the locking element completely surrounds an exterior surface of the valve stem, the enlarged portion or a transition area between the two. As described above, the annular locking element may also be located on the stem or connecting radius.

[0084]Seating surfaces 120, 122 in the enlarged portion 102 are preferably formed by grinding, machining or casting. The depth of the seating surfaces 120, 122 may be greater than 0.01 cm greater than 0.015 cm, and preferably greater than 0.02 cm.

[0085]The annular locking component 106 may be composed of any structurally sound material that can withstand the heat of the motor, the stress of the motor and the chemical emissions and materials (e.g., lubricants, fuel, etc.) it comes into contact with. Most preferred materials would be metals, alloys, ceramics, composites, reinforced materials, high temperature resistant polymers and composites, layered materials, and coated materials (e.g., ceramic coated metal, polymer coated metal, metal coated ceramics, metal coated reinforced high temperature polymers, etc.), with an objective to make the valve assembly light weight and cost effective.

[0086]FIG. 6 shows an alternative embodiment of a valve head 200 according to technology of the invention described herein. In this embodiment, peripheral ring 202 is slidably mounted to an enlarged portion 204. Ring 202 includes a wider, thicker flange 214 and outwardly directed flange 216 of annular locking component 215 is similarly wider and thicker. Such a structure will not wear out as quickly as the extensions used in the prior art such as Huff and Marine, where very small dimensions were tolerated. The flange 216 of the locking element 215 may be integrally formed as part of the valve base 100, or may be formed separately.

[0087]While this invention has been disclosed with reference to its presently-preferred embodiment, it is not limited thereto. For example, the outwardly directed flange 216 may be formed by first providing an extra amount of material on the enlarged portion 204, and after placement of the peripheral ring, pressing the extra material outwardly (away from a central valve stem axis), forming the outwardly directed flange that locks the ring to the enlarged portion. This extra material could be provided in the form of lip that extends in a direction parallel to the central axis of the valve stem, rather than radically outwardly from the stem prior to pressing. Rather this invention is limited only insofar as it is defined by the following set of patent claims and includes within its scope all equivalents thereof.

Claims

1. A method of manufacturing an intake valve for an internal combustion engine comprising:providing a valve base comprising an elongated valve stem and an enlarged portion, the valve base having an inner seating surface;providing a floating peripheral ring with an outer valve seat for seating with a cylinder head seat, an inner seat for seating with the inner seating surface of the valve base, and having an inwardly directed locking flange;providing an annular locking component having an outwardly directed flange for locking the floating peripheral ring to the valve base;positioning the floating peripheral ring onto the valve base so that the floating peripheral ring is movable with respect to the valve base;positioning the annular locking component over the valve base and floating peripheral ring;affixing the annular locking component to the valve base to define a range of motion for the floating peripheral ring with respect to the valve base; ande) thereby slidably locking said peripheral ring to said valve base by the outwardly directed flange of the locking component.

2. The method of claim 1, wherein the annular locking component comprises an annular locking ring and wherein the outwardly directed flange of the annular locking ring is continuous.

3. The method of claim 2 and further comprising providing the floating peripheral ring prior to positioning the annular locking element over the valve base and floating peripheral ring.

4. The method of claim 2 wherein the annular locking ring is locked by means of welding.

5. The method of claim 1, wherein the annular locking component is attached to the valve base by means of threading.

6. The method of claim 1 wherein the locking component is combined with the enlarged portion to form a single unitary structure.

7. The method of claim 1 wherein the enlarged portion includes at least one machined surface for receiving the annular locking component, and wherein the annular locking component is affixed to the enlarged portion to form a single unitary structure.

8. The method of claim 1, wherein the annular locking component is formed of a plurality of elements that are each permanently or removably affixed to a portion of at least one of the valve stem, the enlarged portion and a connecting radius there between.

9. The method of claim 2 wherein a diameter of the annular locking component is smaller than a diameter of the enlarged portion.

10. The method of claim 1 wherein the valve is formed from metal, composite, alloy, ceramic or plastic.

11. The method of claim 1 wherein a coating is applied to at least a portion of the valve and the coating comprises a low friction coating composition, insulating composition or corrosion-resistant composition.

12. The method of claim 1 wherein the annular locking component is permanently or removably affixed to the valve base.

13. The method of claim 1 wherein the composition of the valve base comprises a first metal or first metal alloy and the composition of the floating peripheral ring comprises a second metal or second alloy different from the first metal or metal alloy.

14. An internal combustion engine comprising an intake valve manufactured according to the method of claim 1.

15. A method of manufacturing an intake valve for an internal combustion engine comprising:a) providing a valve base with a valve stem and an enlarged portion and having an internal seat area thereon;b) positioning both a floating peripheral ring and an annular locking component on a region of the enlarged portion, the locking component including an outwardly directed flange that engages an inwardly directed flange of the floating peripheral ring;c) after step b), securing the locking component to the valve base in a manner that provides a sliding relationship between the floating peripheral ring and the valve base thereby limiting a length of movement of the peripheral ring with respect to the valve base.

16. The method of claim 15 wherein before step c), the valve base has a recess formed therein sized to receive the locking component.

17. The method of claim 16 wherein the recess is formed by machining.

18. A method of manufacturing an intake valve for an internal combustion engine, comprising:a) providing a valve base with an elongated valve stem, the valve stem having a central longitudinal axis, and having an enlarged portion, the enlarged portion having an inner seat for receiving a floating peripheral ring,b) providing a floating peripheral ring, the ring having a central ring axis, an exterior seat for mating to a cylinder head seat and an internal seat for mating to the inner seat of the enlarged portion;b) positioning the floating peripheral ring onto the enlarged portion of the valve base so that the floating peripheral ring is movable along the central longitudinal axis, wherein the central ring-axis is coaxial with the central stem axis;c) positioning a locking ring for locking the floating peripheral ring to the valve base, wherein the locking ring includes an outwardly directed locking element;d) locking the locking ring to the valve base to allow the peripheral ring to move in a direction defined by the central ring axis defining a range of motion for the floating peripheral ring; ande) thereby slidably locking said peripheral ring to said valve base by the outwardly directed locking ring.

19. The method of claim 11 wherein the lock element comprises a third metal or composite different from the first metal and the second metal.

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