US3518976A - Means for controlling valve-open time of internal combustion engines - Google Patents

Description

July 7, 1970 N. c. THUESEN MEANS FOR CONTROLLING VALVE-OPEN TIME OF INTERNAL COMBUSTION ENGINES Filed Nov. 29. 1968 s 7 &4 M wa I\\\\\\\\ Q 55 N arms: I l I g 15 :l 51 49 53 N I N 25 46 TU/A/ZETMA/V/FUZD HYDRAULIC V4]. V5 L/F7ER Z5 as 10 l ENVENTOR. I 26 v 27 Ma c. Z'Hl/EJEN United States Patent Office 3,518,976 MEANS FOR CONTROLLING VALVE-OPEN TIME OF INTERNAL COMBUSTION ENGINES Niel C. Thuesen, 6021 Compton Ave., Los Angeles, Calif. 90001 Filed Nov. 29, 1968, Ser. No. 780,112 Int. Cl. F011 1/24, 1/34, 3/10 US. Cl. 123-9016 5 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention The invention relates to engine performance wherein the poppet valves of internal combustion engines are retained open for the maximum degrees of rotation of the camshaft at highest engine speed and lowest inlet manifold vacuum (open throttle), and said valves are retained open for minimum degrees of camshaft rotation at lowest engine speed and highest inlet manifold vacuum (idling throttle). The duration of valve opening in degrees of camshaft rotation will vary between the above high and low extremes and correspond with changes in engine speed and/or inlet manifold vacuum. This results in a cleaner, more efiicient and better running engine, particularly in the environment in which modern automobiles perform.

SUMMARY OF THE INVENTION This invention has general basis on the means for controlling the movement of a poppet valve as disclosed in the patent to the applicant herein, No. 3,404,666, dated Oct. 8, 1968. The present combination comprises, generaly, a poppet valve 5 for controlling flow, in either direction, through an engine port 6, poppet-controlling means 7 on the end of the stem 8 of said valve, a tappet 9 operatively engaged with said poppet-controlling means 7, resilient means 10 incorporated in the poppet-controlling means biasing the poppet valve in a port-closing direction, a camshaft 11, an hydraulic valve lifter 12 operatively engaged with the camshaft, an operative connection 13 between the litter and the mentioned tappet and including resilient means 14 in opposed balancing relation to the first-mentioned resilient means 10, means 15 to vary the pressure of oil in the valve lifter to change the balanced condition of the two normally-balanced resilient means, and means 16 controlled by variations of vacuum in the inlet manifold of said engine for operating the oil-pressure-varying means to increase the pressure of oil flowing to the lifter when the vacuum in said manifold is decreased, and to decrease such oil pressure when the vacuum in the manifold is increased.

It is an object of this invention to provide means, as above exemplified, for controlling valve-open time of an internal combustion engine so that the duration of such time varies from a minimum at lowest engine speed to a maximum at highest engine speed.

Another object of the invention is to provide means, as above characterized, in which the respective lowest and highest engine speeds, as well as speeds therebetween, create corresponding degrees of vacuum in the inlet marlifold of the engine, which correspondingly alter the normal operative movement of the valve.

Patented July 7, 1970 This 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, one embodiment of the present invention, which is given by way of illustration or example only.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, like reference characters designate similar parts in the several views.

FIG. 1, in broken semi-diagrammatic form, shows the present valve-controlling means in cross-section.

FIG. 2 is an enlarged partly elevational and partly sectional view of the poppet-controlling means of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The valve 5 that is shown is of the poppet type for controlling flow of fuel from the port 6 of an engine block 20 into a cylinder in said block, or discharge of.

the gases of combustion from said cylinder through a similar port to exhaust. The following description will more particularly deal with a mechanism for controlling the movement of a valve associated with the seat 21 of an intake port.

The poppet-controlling means 7 is shown as disposed in a space 22 in the tappet 9 between an upper face or wall 23 and transversely spaced ledges 24, said wall and ledges constituting opposed abutments. Said means 7 comprises a body 25 having support engagement with the tappet ledges and having a lower frustoconical portion 26, the wall of which, as viewed from above, being convex. The same has an axial opening 27 that has clearance around the stem 8, which extends therethrough.

The means 7 further comprises an enlarged member 28 fixedly mounted on the end of the valve stem 8 and having an abutment face 29 directed toward the face 23 of the tappet and adapted for operative engagement therewith, and a member 30 on the stem 8 below the enlarged member 28, provided with a concave face 31 in opposed relation to the convex wall 26 on the body 25. A cover member 32 interconnects the body 25 and the member 30 in a manner to permit relative longitudinal movement therebetween to vary the space between the wall 26 and the face 31, as can be seen from a comparison between FIGS. 1 and 2.

The resilient means 10 may comprise a circumferentially arranged complement of flexible elements, as in FIG. 1, or a plurality of complements of similarly arranged flexible elements, as in FIG. 2, the same, by their outer peripheral portions, being clamped between the body 25 and the cover member 32 and extending radially between the mentioned convex portion 26 and concave face 31. Relative longitudinal movement of the stem 8 and tappet 9 thereby increases or decreases the bias of said resilient means 10, being least when the valve 5 is unseated and the abutment faces 23 and 29 are engaged, and being greatest when the valve 5 is engaged with the seat 21 and the tappet 9 is subject to a force moving the same and the body 25 of the means 7 in a direction away from the seated valve.

The camshaft 11, in the usual Way, has a lobe 33 in operative engagement with the hydraulic valve lifter 12. Said lifter is shown in semi-diagrammatic form and is tended to be typical or conventional of such devices. In the usual way, by a pipe or passage 34, pressure oil 35 from the pump that provides lubricating oil to the engine is conducted to the valve lifter, the same being proportional to or varying in accordance with the pressure generated by said pump and having the effect of varying the force which the lifter applies to the operative connection 13 between said lifter and the tappet 9.

Said connection 13 is shown as a rod 36 with an end 37 thereof operatively engaged with the valve lifter 12, a link 38 connected to the tappet 9, and a rocker arm 39 on a rocker shaft 40 connecting said link and the end 41 of the rod 36 that is .opposite to the lifter end 37.

The resilient means 14 comprises a compression spring 42 around the rod 36 between an abutment 43 on said rod and a fixed abutment 44 on the engine block 20, which also carries the valve lifter.

According to the invention, the maximum spring-biases of the rates of the resilient means and 14 are prechosen to be in balance or equilibrium when there is no force being exerted on the push rod 36 by the valve lifter. Said state of equilibrium is reached preferably when the clearance between the abutment faces 23 and 29 is between the two limit positions of the resilient means 10, as in FIGS. 1 and 2.

Upon an application of force on the stem 36 applied by a valve lifter, the state of equilibrium will be reached when there is less clearance between the stem 8 and tappet 9, i.e., between the abutments 29 and 23. Thus, the greater the force on the rod 36, the smaller will such clearance become.

Since the normal force applied by a hydraulic valve lifter on the rod 36 is proportional to the oil pressure of the engine, as generated by its pump, changing said pressure will effect a corresponding change in said clearance between the abutments 23 and 29. Hence, when the clearance between the abutments is increased, the valve 5 is off its seat 21 for fewer degrees of camshaft rotation than normal, and if the clearance is decreased, the valve is off its seat for a greater number of degrees of camshaft rotation.

This operation, in the present invention, is effected by the means and 16. As the engine speed increases, the inlet vacuum in the inlet manifold increases, such negative pressure or suction being manifested in the tube of passage 45 leading to a cylinder 46 in the means 16 and being effective on a piston 47 in said cylinder to pull the same in a direction counter to the bias of an expansion spring 48. The latter encircles a stem 49 that extends upwardly from said piston 47. The greater the suction in cylinder 46, the greater the downward movement of the piston.

The means 15 is shown as a cylinder 50', preferably smaller than the cylinder 46, and a plunger 51 in said cylinder 50 and fitted on the upper end of the stem 49. Said means 15 and 16, in this case, are provided in a housing 52 in which the cylinders 46 and 50 are formed with a passage 53 connecting said cylinder and housing the spring 48, the latter having abutment, at one end, with the bottom of the plunger 51 and, at the other end, with an abutment plate 54. A lateral oil bypass 55 is provided in said housing 52 in position to be closed by the plunger 51 when the suction in cylinder 46 is low, thereby shutting off oil flow from line 34 to said bypass. The latter is so located as to be opened to bypass oil from line 34, a lesser amount at a low increase of suction in the inlet manifold, and an increasingly greater amount as the suction in the engine increases. FIG. 1 shows the means 15 and 16 positioned to provide a small connection between the cylinder 50 and the bypass 55. It will be clear that said connection will increase in size as the suction in the cylinder 46 increases, and will close completely when the suction lowers or the engine is stopped.

It will be clear that the full pressure of pump oil on the lifter 12 will cause corresponding movement of the rod 36 and compression of the spring 42. The valve 5 will remain closed under bias of the resilient means 10 as the tappet 9 moves downwardly, causing a contraction of the space between the abutments 23 and 29. Therefore, the cam lob 33, acting through the lifter 12 on the operative connection 13 with its spring compressed as above, will cause the valve 5 to open earlier. Conversely, the less the compression of the spring 42, the later will the valve open. The passage, below the plunger 51, is vented as at 56.

It will be understood that either or both of the spring means 10 and 14 may be pre-stressed and chosen to achieve a state of equilibrium that, ordinarily, holds the tappet abutment 23 spaced from the valve abutment 29 a distance smaller than maximum, as in FIG. 1, but not in contact, as in FIG. 2.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying out the invention, the construction is, of course, subject to modification without departing from the spirit and scope of the invention.

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

1. Mechanism to control the duration of time that a poppet valve of an internal combustion engine having an inlet manifold is open, and which is moved to open position by a lobe on the camshaft of the engine, and an hydraulic lifter supplied by a flow of oil under enginegenerated pressure and which is operatively engaged with said cam lobe, said poppet valve being movable between open and closed positions by a tappet, there being a lost-motion connection between the valve and tappet limited by engagement of abutment faces, one on the valve and the other on the tappet, said means comprising.

(a) means constituting an operative interconnection between the valve lifter and the tappet, including first spring means interposed therebetween and biasing the valve in a direction to engage the abutment faces, and second spring means biasing the interconnection in a direction opposing the first spring means and in equilibrium therewith when the valve is closed and a predetermined clearance between the abutment faces is achieved, the rates of said spring means being chosen accordingly,

(b) bypass means to vary the pressure in a line conducting operating oil to the valve lifter, thereby to change the mentioned equilibrium of the spring means to increase or decrease the space between the mentioned abutment faces according to whether the oil pressure is increased or decreased, and

(0) means operated by variations of vacuum in the inlet manifold of said engine and controlling the bypass means.

2. Valve control mechanism as claimed in claim 1 in which the bypass means comprises:

(a) a cylinder provided with an inlet line extending from the mentioned oil-conducting line and With a lateral bypass outlet, and

(b) a plunger in said cylinder movable by the vacuumoperated means from a bypass outlet-closing position to a position opening said bypass outlet to a degree conforming to the degree of movement of the vacuum-operated means.

3. Valve control mechanism as defined in claim 2 comprising a spring engaged with the plunger to bias the same in a direction counter to the vacuum-operated means to move the same to bypass outlet-closing position.

4. Valve control mechanism as defined in claim 3 in which the vacuum-operated means comprises a cylinder provided with a vacuum-conducting line, and a piston in said cylinder and connected to the mentioned plunger, operative in said cylinder and movable under vacuum in a direction to move the plunger to bypass-opening position.

5. Valve control mechanism as defined in claim 4 com- 5 prising a housing, said oil and vacuum cylinders being 2,780,912 provided in opposite ends of said housing, and the plunger 2,804,061 and piston being connected by a stern extending from one 2,931,347 cylinder into the other. ,066, 9 1 3,361,122 References Cited 5 3,382,854 UNITED STATES PATENTS figs??? 2,305,787 12/1942 Kales. 2,484,109 10/ 1949 Meinecke. 2,494,183 1/ 1950 Lincoln.

6 Miller. Gamble. Williams. Colton. Wagner. Steiner 123-90 Thuesen 12390 Weiler.

10 AL LAWRENCE SMITH, Primary Examiner

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