US2346525A - Internal combustion engine - Google Patents

Description

April 11, 1944- H. E. VOORHIES INTERNAL COMBUSTION ENGINE Filed July 20, 1942 IN V EN TOR.

W v 9 I w BY HHRRY E. VOORH/ES fiTfiaRNEY Patented A r. 11,1944

g 2.346.525 INTERNAL COMBUSTION ENGINE.

Harry E. Voorhies, Grosse Pointe Woods,Mich.,

assignor to Eaton Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application July 20, 1942, Serial N 451,546

14 Claims.

This invention relates generally to an improvement of the parts of the valve gear mechanism of an internal combustion engine, and, more particularly, concerns a combination self-compensating hydraulic tappet and automatic valve rotator for use in the valve gear of internal combustion engines.

The objects and advantages of an automatic self-compensating tappet of the hydraulic type is disclosed in the patent to C. Voorhies #2,074,034, issued March 16, 1937, and other patents directed to the same general subject matter, assigned to the same assignee as that of the present invention; and for a further detailed description thereof reference may be had to said prior patent, only so much of the operation thereof as is necessary to a complete understanding of the present invention will be undertaken.

Likewise, the objects and advantages of a valve rotating means has been well explored in the prior art. Some of the most important functions of which are to remove seat and stem deposits before the accumulation thereof becomes objectionable, and in event of engine block distortion continuous rotation of the valve prevents local overheating and guttering of the valve seating surface at any one point of the valve face. Accordingly, the present invention has integrated these two units into a novel combination selfcompensating hydraulic lifter and intimately associated valve rotator hydraulically operated thereby.

Amongthe objects of the present invention is the provision of a combination self-compensating hydraulic valve lifter and valve rotating means associated therewith and hydraulically operated thereby; the provision in a combination hydraulic valve lifter and rotator, as described, of a predetermined fiuid escapernent or leak down rate.

chamber below a 'second 'reciprocable plunger arranged to'contact the valve spring retainer and be supported on I an incompressible hydraulic cushion; the provision in a combination hydraulic valve lifter and rotator, as described, in which said second hydraulically cushioned plunger is received in the valve lifter body. concentrically surrounding the upper portion of vsaid first plunger means, and is arranged to have a predeteri'nined fluid escapement therefrom bya selective fit with its associated parts;' and the provision of substantially positive sealing means in a combination self-compensating hydraulic valve lifter and rotating means, as described, operated thereby which directs the predetermined fluid escapement or leak down rate along a selected path of travel. g

A further object of the invention is the provision of a materially simplified and improved combination of self-compensating hydraulic valve lifter and rotator operated thereby, which may be readily manufactured with conventional production equipment in an economical manner in large quantities.

Further, and other objects and advantages of the invention reside in the novel combination and arrangement of parts about to be described, when considered in conjunction with the attached drawing forming a part of this specification, and are more particularly pointed out in the appended claims.

In the drawing, like numerals refer to corresponding parts in the various views, and in which: Fig.-I isa vertical sectional view through a ortion of an internal combustion engine block adjacent the valve and tappet chamber thereof and illustrating a representative embodiment of .the present invention; and

Fig. 2 is a longitudinal sectional view through a combination hydraulic tappet and valve rotator operated thereby, according to the teaching of this invention. I v

Reference will now be made to Figs. 1 and2 of the drawing for a complete description'of the operation and function of the combination selfcompensating hydraulic valve tappet and rotator operated thereby, generally designated 6. A vertical sectional view'through a portion of an internal combustion engine I reveals a poppet valve 2 and a :valve spring 3, normally urging the valve with engine block The hydraulically operated tappet and rotator, generally designated 6, is comprised in part of a tappet body I, having a cam-contacting end 8 arranged to be actuated by a camshaft with a cam lobe thereon (not shown). Inthis instance, while a mushroom type tappet body is disclosed for purposes of illustration, the invention is equally susceptible for-adaption in a so-called barrel type tappet body without alteration in any respect. I

' i The tappet body 1 comprises a hollow cylindrical member open at one end and closed atthe other end to form an oil reservoirp An opening through a wall of the tappetbodyhas a.

chamber beyond the valve means.

rooved entrance thereto providing continuous registration withthe oil supply. Within the bore of the tappet body a separate cylindrical sleeveor cylinder I2 is supported intermediate the ends thereof and has at one end. a fluid inlet opening l3 in communication with theoil reservoir 9 in the closed end of the tappetbody. At the opposite side of the fluid inlet opening 13 is a. check valve means 14 for regulating flow of. hydraulic fluid from the reservoir to a high compression While a valve ing side of the cam ramp thevalve 2 will be lifted throughits opening event by the portion 18 of the plunger l1. In theevent the unit is not full of oil at the time of starting the tappet will still operate, but with reduced lift for the valve 2,'by bottoming in the separate cylinder l2 on the top of the check valve means. During the closing event of the valve, when the cam contacting end of the tappet body is onthe 'descending side of the cam ramp, the load of the valve gear willbe removed from the tappet during a seat, ball checkvalve, and cage member afford- I ing limited travel thereto are shown, for purposes of illustration, it will be apparent other valve means such as a flat disc or plate valve could be used equally well, but since the valve means forms are nowshownt Within the separate cylindricalsleeve member I2 is aplunger I'l reciprocable therein and fitted portion of the travel around the base circle of the cam lobe, and, movement of plunger l1 outward, will cause a reduced pressure or suction in back of the check valve mean H which will then rise on its seat and permit flow of hydraulic I fluid from the oil reservoir to fill the space below the plunger-in the end ot-the separate cylper se forms. no part of this invention alternative with a clearance with respect to its cylinder so as to provide a predetermined fluid escapement therebetween.

called leak downratedetermines the rate of This fluid escapement or socompensation of the tappet, as will be more fully explained hereinafter, while the reduced outer end portion l8 of the plungeris extended to con tact the lower stem end or foot of the valve 2 tolift the valve in its normal opening and closing function without affording any clearance in. the

inder; continues until any lash is removed from the valve gear and zero clearance -iseffected therein.

In the next portion of the valve cycle the valve isagain raised off its seat by the cam and the ridingupon a. substantially incompressible col umn of hydraulic fluid. I

valve train which produces noisy operation and. lash in the valve gear. A sealing ring 20 of fiow- I able but substantially incompressiblematerial which may be of a rubber 'likematerial or soft metallic packing serves to substantially seal the. outer periphery Ofthe separate. cylindrical member l2 above its intermediate supporting seatso as to prevent by-passing of operating fluid from the oil reservoir except along a predetermined path of travel, i. e. throughthe inlet opening ill plunger 22 which is extended to contact a portion of the valve spring retainer 4 to remove the load of the valve spring 3 from the valve 2 to effect rotation thereof during a portion of it operating cycle, as will be more fully explained hereinafter.

A second annular sealing ring 24, similar to ring 20, surrounds the outer periphery of plunger 22 to substantially prevent any fluid escapement thereby, while' the inner opening in the plunger 22 is fitted with respect to the reduced end portion l8 of the plunger I! to provide a predetermined fluid escapement or leak down rate therebetween. A snap ring 26 sprung into a recess in the outer end of the bore of the tappet body I prevents disassembly of the component parts of the device housed in the tapped body, and, in the event of a stuck valve, provides limited travel of the plungers in attempting to compensate the clearance in the valve gear by following up the valve. A spring member 28 seated in an outer counterbored end of the separate cylinder l2 and bearing against a recessed inner portion of he annular plunger 22 is arranged to constantly bias the same outward with respect to the tappet body.

In operation of the hydraulic self-compensat ing tappet: The cam-shaft and cam lobe thereon (not shown) during the time the cam-contacting end 8 of the tappet body is on the ascend- Provisionhas been made to accommodate expansion in the valve gear train, through elongation of the parts due to heat upon reaching normal operating temperature, by the aforementioned fit between the plunger l1 and its .cylin der l2 whereby a predetermined fluid escapement or leak down ratemay occur. during the valve cycle. The foregoing cycle of operation is then repeated indefinitely and represents the usualoperation of the self-compensating hydraulic tappet .per se, asdisclo'sedin the priorpatent' above identified.

Now having reference to the hydraulically actuated valve rotating mean in the tappet body it will be apparent that fluid escapement by the plunger I! will fill the chamber between it and the inner counterbored end of the second annular plunger 22, which upon outward movement thereof, under the action of spring 28, will induce more fluid into the chamber to cause the outer end of the plunger 22 to independently act against a portion of the valve spring retainer 4 keyed to the valve to relieve the load of the spring 3 thereof and free the valve to rotate. It is to be noted that a feature of this device is that during acceleration of the valve, 1. e. in the opening portion of the cycle, the'total inertia load of the valve is on the smaller plunger I1 and this fact tends to induce rotation during acceleration and to discourage rotation during deceleration. It has been determined by experimentation that it-is a decided disadvantage to have the valve turning at the time contact is made withlt seat since this causes the valve to sink into the seat.

The relative distribution between the load 01 the valve and its spring gear in this instance is approximately in the order of 20% for the valve load on the smaller plunger l1, and of the total load of the valve spring assembly being supported by the large annular plunger 22. The desired pressure on the valve or the proportion 01 the load carried by the small and large plunger:

This outward-movement of the plunger equal to the area of the plunger times the oil pressure in the upper pressure chamber adjacent the spring 28. The normal load on the larger plunger 22 is equal to the area of the annular portion of the plunger times the oil pressure in the upper chamber. Therefore, the oil pressure being the same in each instance, the proportion of the total load carried by each plunger remains the same regardless of thevalue of the total load, and, thus, a hydraulic equalization is eirected between the two. This is true, of course, only if the load of the light spring 28 is disregarded. The inner portion of the plunger I! is operable under a dashpot action, which,

2 while it is arranged to permit slow escapement of oil to fill the upper compression chamber, will not move quickly, and, therefore supports the valve I during acceleration. From the foregoing it will be evident that this device has two separate automatic adjustments, first, the larger annular plunger 22 is maintained in contact with, or at zero clearance against, a portion of the valve spring retainer 6, and therefore supports the load of the valve spring during the valve open event; the reduced outer end portion H! of the smaller plunger H then adjusts itself independently to contact'the foot end of the stem of the valve 2, and accordingly, the distance from the valve spring retainer key to the end of the valve stem is adjusted to zero clearance independently of the other adjustment movement.

In the practical application of this device it has been found that the sealing ring 2t may be omitted provided the plunger 22 is fit to the proper clearance in the bore of the tappet body '1 so as not to allow excessive leakage around the outside of the plunger., However, by use of the sealing ring 24, costly manufacturing operations are obviated and the fluid escapement is caused to follow a selected path of travel to effect hydraulic actuation of the plunger 22 which relieves the load of the valve spring, normally tending to hold the valve down, and frees the valve to rotate when being lifted. Likewise, by a controlled rate and path of fluid escapement through the annular plunger 22 the rate of compensation is affected and valve rotating speed regulated.

From the foregoing disclosures it will be apparent there has been revealed a novel combination self-compensating valve tappet and. rotating means hydraulically actuated thereby, which, among other things, embodies the objects and advantages of the invention as first enumerated. It is notintended to be limited to the specific embodiment of the invention described and shown, which is merely for purposes 01 illustration, as many formal modification in actual practice will now be suggested to those skilled in the art to which it is related, and the spirit of the invention is considered commensuate with the scopev and substance of the following claims.

WhatiI claim is:

f1. Thefmethod of producing valve rotation in the poppet valves of an internal combustion en- 'gine having hydraulic self-compensatin tappets interposed in the valve train thereof which com prises, eifecting a predetermined escapement of hydraulic operating fluid from said tappets, and utilizing the escaped fluid as a hydraulic cushion to relieve the normal Jperating load of the valve gear train on the valve to thereby free thevalve fonrotation,

2. Ina" valve gear train, a self-compensating hydraulic valve tappet and rotator operated thereby comprising in combination, a tappet body having a longitudinal bore adapted to receive. an hydraulic compensating mechanism therein, a liquid reservoir in the tappehbore, and means disposed in the tappet bore hydraulically actuated by-said compensating mechanism arranged to contact a portion of the valve gear train and efiect rotation of the valve thereof.

3. In a valve gear train, a self-compensating hydraulic valve tappet and rotator operated thereby comprising in combination, a tappet body having a longitudinal bore adapted to receive an hydraulic compensating mechanism therein, a liquid reservoir in the tappet bore, a plunger reciprocable in said hydraulic mechanism fltted for a predetermined escapement of hydraulic fluid and arranged to contact the foot end of said valve, and means disposed in the tappet bore hydraulically actuated by fluid escapement from I said compensating meehanism arranged to contact another portion of said valve train and free the valve thereof for rotation.

4. In a valve gear train, a self-compensating hydraulic valve tappet and rotator operated thereby comprising in combination, a. tappet-body havinga longitudinal bore adapted to receive an hydraulic compensating mechanism therein, a liquid.reservoir in the tappet bore, a. plunger reciprocable in said hydraulic mechanism fitted for a predetermined escapement of hydraulic fluid and arranged to contact the foot end of said valve, and means comprising a second plunger disposed in the tappet bore hydraulical y actuated by fluid escapement from said compensating mechanism arranged to contact a valve spring retainer of said valve gear train to relieve the load thereof and free the valve for rotation.

5. Ina valve gear train, a self-compensatin hydraulic valve tappet and rotator operated thereby comprising in combination, a tappet body having a longitudinal bore adapted to ,receive an hydraulic compensating mechanism therein, a liquid reservoir in the tappet bore, a plunger reciprocable in said hydraulic mechanism fitted for a predetermined escapement of hydraulic fluid and arranged to contact the foot end of said valve, means comprising a second plunger disposed in the tappet bore hydraulically actuated by fluid escapement from said compensating mechanism arranged to contact a valve spring retainer of said valve gear train to relieve the load thereofand free thevalve for rotation, and said second plunger having an area proportional to the area of the first named plunger to control the rate of valve rotation.

,6. Ina valve gear train, a self-compensating hydraulic valve tappet and rotator operated thereby comprising in combination, a tappet body having a longitudinal bore adapted to receive an hydraulic compensating mechanism therein, a liquid reservoir in the tappet bore, a plunger reciprocable in said hydraulic mechanism arranged to'contact the foot end of said valveand effect a predetermined escapement of hydraulic fluid, means comprising a second plunger disposed in the tappet bore hydraulically actuated by fluid escapement from said compensating mechanism arranged to contact a valve spring retainer of said valve gear train to relieve the load thereof and free the valve for rotationland said second plunger arranged to provides. predetermined escapement of, hydraulic fluid therefrom to effect a selected rate, of compensation of the tappet and rotator operated thereby.

7. In a valve gear train, a self-compensating hydraulic valve tappet and rotator operated thereby comprising in combination, a tappet body having a longitudinal bore adapted to receive an hydraulic compensating mechanism therein, a liquid reservoir in the tappet bore, a plunger reciprocable in said hydraulic mechanism arranged to contact the foot end of said valve and eilfect a predetermined escapement of hydraulic fluid, means comprising a second plunger disposed in the tappet bore hydraulically actuated by fluid escapement from said compensating mechanism arranged to contact a valve spring retainer of said valve gear train to relieve the load thereof and .free the valve for rotation, and said second plunger arranged to provide a predetermined escapement of hydraulic fluid therefrom less than the fluid escapement by said firs plunger to effect a selected rate of compensation of the tappet and rotator operated thereby.

8. In a spring loaded valve gear train having variable inertia loads developed during normal.

operation thereof, a self-compensating hydraulic valve tappet and rotator operated thereby comprising in combination, means normally supporting a main part of the load on a keeper of said valve spring, other means normally supporting a smaller part of the load on the foot end of said valve, hydraulic equalization means between said two load supporting means, and dashpot means on said means supporting the load on the foot end of said valve to carry an instantaneous load greater than its normal portion of the load.

'9. In a spring loaded valve gear train having variable inertia loads developed during normal operation thereof, a self-compensating hydraulic valve tappet and rotator operated thereby comprising in combination, means normally supporting a part of the load on a keeper of said valve spring, other means normally supporting a smaller part of the load on the foot end of said valve, and hydraulic equalization means between said two load supporting means including independent self-adjustment of each.

10. In a spring loaded valve gear train, a selfcompensating hydraulic valve tappet and rotator operated thereby comprising in combination, a tappet body having a longitudinal bore adapted to receive an hydraulic compensating mechanism therein, a liquid reservoir in the tappet bore, a first plunger reciprocable in said hydraulic mechanism arranged to contact the foot end of said valve, means comprising a second plunger disposed in the tappet bore hydraulically actuated by fluid escapement from said compensating mechanism arranged to contact a valve spring retainer of said valve gear train to relieve the means hydraulically actuated thereby to regulate escapement of hydraulic fluid along a predetermined path of travel.

12. In a valve gear train, a self-compensating hydraulic valve tappet and rotator operated thereby comprising in combination, a tappet body having a longitudinal bore adapted to receive an hydraulic compensating mechanism therein, a liquid reservoir in the tappet bore, means disposed in the tapppet bore hydraulicallyactuated by said compensating mechanism arranged to contact a portion of the valve gear train and effect rotation. of the valve thereof, substantially positive sealing means associated with said hydraulic compensating mechanism and the said means hydraulically actuated thereby to regulate escapement of hydraulic fluid along a predeter-- mined path of travel, and said predetermined path of fluid escapement arranged to provide control over the rate of tappet compensation and the valve rotated thereby.

13. In a spring loaded valve gear train, a self compensating hydraulic valve tappet androtator operated thereby comprising in combination, a tappet body having a longitudinal bore adapted to receive an hydraulic compensating mechanism therein, a liquid reservoir in the tappet bore, a first plunger reciprocable in said hydraulic mechanism arranged to contact the foot end of said valve, means comprising a second plunger disposed in the tappet bore hydraulically actuated by fluid escapement from said compensating mechanism arranged to contact a valve spring retainer of said valve gear train to relieve the load thereof and free the valve for rotation, spring means normally biasing said second plunger outward with respect to said first plunger, and retaining means preventing disassembly of the tappet and rotator and limited travel thereof with respect to the tappet body in event of a stuck valve and the tappet compensator and rotator attempting to follow-up the same.

14. In a spring loaded valve gear train, a selfcompensating hydraulic valve tappet and rotator contact a portion of the valve gear train and operated thereby comprising in combination, a tappet body having a longitudinal bore closed at one end and open at the other end and adapted to receive hydraulic fluid, a fluid reservoir in the closed end of said bore, a hydraulic compensating mechanism received in the open end of said bore, check valve means in the hydraulic mechanism regulating liquid movement thereinto, a first plunger reciprocable-in said hydraulic mechanism having a reduced outer end arranged to contact the foot end of the valve in said valve gear train, said first plunger fitted in said mechanism for a predetermined escapement of hydraulic fluid thereby to control the rate of tappet compensation, a second annular plunger means concentrically disposed around the reduced outer end portion of the first plunger reciprocable mounted in the open end of said tappet body and having an outer and arranged to contact a valve spring retainer of said valve gear train to relieve the load thereof and free the valve for rotation, said second plunger normally biased outward with respect to said first plunger by spring means and provided with a predetermined rate of fluid escapement'thereby, and said second plunger hydraulically actuated by the fluid escapement from said first plunger means and having an effective area proportional to the area of the first plunger to control the rate of valve rotation.

HARRY E. VOORHIES.

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