US3404666A

US3404666A - Means for controlling the movement of poppet valves

Info

Publication number: US3404666A
Application number: US691366A
Authority: US
Inventors: Niel C Thuesen
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-12-18
Filing date: 1967-12-18
Publication date: 1968-10-08
Anticipated expiration: 1985-10-08

Description

N. C. THUESEN Oct. 8, 1968 MEANS FOR CONTROLLING THE MOVEMENT OF POPPET VALVES Filed Dec. 18. 1967 INVENTOR IV/EL C THUESE/V ATTOF/Vf) United States Patent 3,404,666 MEANS FOR CONTROLLING THE MOVEMENT OF POPPET VALVES Niel C. Thuesen, 6021 Compton Ave., Los Angeles, Calif. 90001 Filed Dec. 18,1967, Ser. No. 691,366 7 Claims. (Cl. 123-90 ABSTRACT OF THE DISCLOSURE Compens ator means interposed between a poppet valve and the cam-controlled mechanism that reciprocates the same, said means including flexible means which, due to acceleration of the action of said mechanism, flex so the poppet moves with increased velocity over that of the tappet that carries it in the direction away from its seat toward open position, said poppet thereby moving greater distance than the tappet and being held open for a longer period of time due to the additional movement of the poppet relative to the tappet.

Background of the invention In four-stroke cycle internal combustion engines, especially for automotive and aircraft use, the intake and ex haust valves are normally controlled, in their opening and closing movements, by cam-controlled mechanisms having preset timed relation. The more accurately the open positions of the valve are timed, the greater the general efiiciency' of operation of the engine as regards fuel economy, and the cleaner the engine will run. Therefore, the exhaust of the gases of combustion will be less noxious, due to improved combustion, and engine performance will be materially improved. If such pinpoint control of move ments of the valves is coupled with prolonged time periods during which the valves remain open, further improvement in combustion efiiciency and general performance, as above, will result.

An object of the present invention is to provide improved compensator means by which the poppet valves of an internal combustion engine of the type referred to are so controlled that theimprovements in performance of such engines, as above enumerated, result.

Another object of the invention is to provide means of the' character referred to which, independently of the cam-controlled movements of the valve-mounting tappet, allows for an additional further movement of the valve poppets at the valve-open positions thereof.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description, which is based on the accompanying drawing. However, said drawing merely shows, and the following description merely describes, preferred embodiments of the present invention, which are given by way of illustration or example only. I

The most pertinent art that may be cited comprises patents issued to the applicant, as listed below: 3,183,901, May 1965; 3,185,139, May 1965; 3,220,391, November 1965; 3,211,138, October '1965 (with C. H. Collins).

The above show various forms of compensators which are devised for allowing the poppet valves to seat properly. The same do not have any teachings respecting the provision of means to provide the mentioned added opening movement of the valves nor the pinpoint control of the valve movement.

Summary of the invention The present improvements are incorporated in a cylinder back 10 which is semidiagrammatically shown and has a cylinder 11 and a flow port passage 12 leading to said cylinder with a valve seat 13 where said passage 12 joins said cylinder 11. Since, in four-stroke cycle engines, each cylinder is provided with at least one inlet and one outlet port, said passage 12 is representative of each such port. In an exemplary manner, a camshaft 14 reciprocates a tappet 15 that is guided for movement in aligned guides 16 mounted on the cylinder block, through the medium of a mechanism 17. A poppet valve 18, in the usual manner, is mounted in said cylinder block 10 to reciprocate and move between a position engaged with the seat 13 to close the port passage 12, and a position spaced therebelow to open said passage. According to the invention, the present poppet-controlling means 19 is carried by the upper end of the poppet stem 20 and is engaged by the tappet 15.

Brief description of the drawing In the drawing, like reference characters designate similar parts in the several views.

FIGS. 1, 2 and 3, in semidiagram-matic form, show three successive positions of the poppet valve and the means controlling the movement thereof.

FIGS. 4, 5 and 6, to an increased scale, show the compensator means and the respective operative positions thereof according to FIGS. 1, 2 and 3.

FIG. 7, to the same scale, is a plan view of the compensator means, partly in section to show detail.

FIG. 8, to a further increased scale, shows a modification of the compensator means.

Description of the preferred embodiments The camshaft 14 is shown with a cam lobe that operates the mechanism 17. The latter is shown as having a lifter 26 which may be a hydraulic lifter for obtaining uniform operation during all engine speeds, a rod 27 connected by a pivot 28 to the upper end of said lifter, a spring abutment 29 on said rod, a compression spring 30 around said rod with one end engaged with said abutment 29 and the opposite end engaged with a fixed abutment 31 on the cylinder block, a rocker arm 32 on a rocker shaft 33 having one arm thereof pivotally connected to the upper end of the rod 27, and a link 34 pivotally connected by one end to an oppositely extending arm of the rocker arm 32, the other end of said link being shown as pivotally connected to the tappet 15.

While FIGS. 1, 2 and 3 show the rod .27 and the axis of the poppet valve 18 parallel, these parts may be arranged so there is an inclined angle therebetween. Irrespective of the chosen arrangement of the parts constituting the mechanism 17, the cam lobe 25, on its rising movement, moves the tappet 15 from its raised position of FIG. 1 to its lowermost position of FIG. 3, when it is at top dead center. This movement is effected against the light bias of the spring 30 and causes the tappet to move a distance represented by the dimension 35 (FIG. 3). In the absence of means on the camshaft 14 to reverse this movement of 3 the means 17, the spring 30 performs this function upon continued rotation of said camshaft.

The present poppet movement-controlling means 19 is shown as disposed in a space 36 in the tappet between an upper wall 37 and transversely spaced ledges 38, the same constituting opposed abutments. Said means 19 is shown as comprising a body 39 preferably having a polygonal formin this case, eight-sided and a lower frusto-conical portion 40, the wall of which is convex as viewed from above. A central or axial opening 41 in said portion has clearance around the stem of the valve 18 which extends upwardly therethrough.

A complement of flexible elements 42 is disposed within the body 39, the number thereof preferably conforming to and fitting against the side faces of said body, said elements 42, as seen in FIG. 7, being clear of each other so each may flex independently of its adjacent elements. Said elements may be flat, or may have some degree of initial flexure imparted thereto. Also, as shown in FIG. 8, instead of a single layer of elements as in FIGS. 4, 5 and 6, two or more layers 42a may be used. The top layer may be flat and the others therebelow may be initially curved or bent to varying degrees so the spring rate of the elements may be interchanged for obtaining the rate of operative movement of the valve as desired.

A member 43 having a central hole for the valve stem 20 is disposed upon said flexible elements 42 and has a lower conical portion having a concave face 44 that cooperates with the convex conical wall 40 to cause flexure of said elements when said body 39 and member 43 are moved toward each other during operation. As shown in FIG. 6, the face 44 is preferably formed to have polygonal sides that have transversely coextensive engagement with the elements 42.

A cover member 45 has a peripheral portion 46 that rests upon the outer portions of said

elements

42 or 42a and is clamped thereagainst by a spunover rim 47 of the body. Said cover member 45 circumscribes member 43 so as to allow relative longitudinal movement of the latter member and the cover-provided body 39. An inturned flange 48 on the upper end of the cover member 45 limits such relative movement.

A nut 49 is threadedly engaged with the upper end of the valve stem 20 and forms retainer means preventing the member 43 from becoming separated from the valve. An abutment end 50 is provided on said nut.

Operation When the cam lobe is in the low position of FIG. 1, the return spring holds the tappet 15 raised to its maximum high position, as indicated by the arrow 51. From FIGS. 1 and 4, it will be seen that in this position, the valve 18 is retained against its seat 13 and that the tappet wall 37 is spaced from the abutment extension 50. Since the upward resilient bias on the tappet 15 causes the body 39 of the means 19 to seat firmly on the ledges 38, and the valve 18 is held fixedly against its seat, the normally unflexed elements 42 will flex to the condition of FIG. 4.

Now, when the cam lobe 25 rises, as in the position of FIG. 2, the initial downward movement of the tappet 15 will move its wall 36 toward the abutment extension 50, thus releasing the flexure imposed by the member 43 on the elements 42, and permitting the latter to flatten out as in FIG. 5. For the initial part of this movement, the tappet moves downwardly but the poppet valve 18 remains seated. Thus, in effect the poppet valve has become shorted by such straightening of the elements 42.

Then, because there now is a direct contact between the tappet wall 37 and the poppet valve 18, the rapidly accelerated movement of the former, as the cam lobe 25 moves from its relatively low angular position of FIG. 2 toward its top dead center position of FIG. 3, causes the valve 18, under this impact, to accelerate, according to the arrow 52, and have increased velocity, causing the valve to move back to its initial relationship with the parts of the means 19 as in FIG. 1, and again flex the elements 42. As a consequence, the opening between the valve and the valve seat, shown by the dimension 53, is greater than the dimension 35, which represents the full tappet movement, less the initial movement of the tappet from its fully raised position of FIG. 1 to the position of FIG. 2 where the encounter of the tappet wall 37 and the abutment extension 50 occurs.

Such controlled acceleration of the poppet movement, causing the valve to remain open longer than if directly moved by the mechanism 17, enables pinpoint opening of the valve, induces eflicient and cleaner engine performance, improved timing of fuel inlet and exhausting of burnt gases, and generally increases efliciency of engine operation.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying out the invention, the constructions are, or course, subject to modification without departing from the spirit and scope of the invention. Therefore, it is not desired to restrict the invention to the particular forms of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In means for controlling the reciprocative movement of a poppet valve and in which a tappet for said valve is reciprocated at a velocity that is greatest when approaching valve-opening position, said valve controlling flow between a cylinder and a flow port with a valve seat provided where said port and cylinder join, the tappet being provided with opposed abutments, means disposed in the space in said tappet between said opposed abutments to control axial movement of the poppet valve, said means comprising:

(a) a member mounted adjacent the upper end of the stem of the poppet valve and provided with a frustoconical portion having a concave face,

(b) a housing around said member and having a convex frusto-conical portion generally conforming to the corresponding portion of the mentioned member, said housing being engaged with one of the mentioned abutments on the tappet and disposed in the mentioned space in the tappet,

(c) a complement of flexible elements within said housing with their outer portions fixedly held therein and the portions directed toward the axis of the valve stem free to flex when engaged from opposite sidesby said frusto-conical portions of the member and the housing, and

(d) an abutment on the end of the valve stem beyond the member having the frusto-conical portion with the concave face,

(e) said end abutment on the valve stem being retained in resilient contact with the tappet abutment that is opposite to the one engaged with the housing,

(f) said poppet valve, while in contact with the lastmentioned tappet abutment, under the mentioned increased acceleration of the tappet, being propelled at an increased velocity which causes flexure of the flexible elements and a movement of the poppet valve that is greater than that of the tappet, thereby increasing the opening to flow between the cylinder and the port passage.

2. In valve movement-controlling means according to claim 1, the mentioned flexible elements being arranged in a single layer thereof.

3. In valve movement-controlling means according to claim 1, the mentioned flexible elements being arranged in plural layers with the layer engaged with the frustoconical portion of the housing being initially curved more than are the elements in the other layers.

4. In a valve movement-controlling means according to claim 3, the intermediate layers of flexible elements being curved to lesser degrees as the least curved layer is approached.

5. In a valve movement-controlling means according to claim 1, the housing having a polygonal outer form and the flexible elements having portions fitting against and extending radially from the outer wall of the housing.

6. In a valve movement-controlling means according to claim 5, a clamp member cooperating with the polygonal wall of the housing to clamp the adjacent outer portions of the flexible elements so the ports of the latter adjacent the axis may flex.

7. In a valve movement-controlling means according to claim 1, the mentioned abutment end being threadedly connected to the end of the tappet stem and constituting a retainer member to hold the member with the concave face in assembly on the valve stem.

References Cited UNITED STATES PATENTS 3,183,901 5/1965 Thuesen 123-90 3,135,139 5/1965 Thuesen 123 90 3,211,138 10/1965 Collins et al 123 90 10 3,220,391 11/1965 Thuesen 123-90 AL LAWRENCE SMITH, Primary Examiner.