US2178732A - Internal combustion engine - Google Patents

Description

No v.'7,'1939 c, ooRHlE 2 ,113,732

INTERNAL COMBUSTION. ENGINE Filed April 14, 1938 2 Sheets-She at 1 'lNVENiOR Carl V0077]: {as

B Y I W 9/54, A TTORNE Y5 Nov. 7, 1939, c; VQORHIES 2,178,732

' INTERNAL coMBUsTmN ENGINE Filed April 14, 1938 2 sheets-sheet 2 ll A IN VENT'OR CarZ War/1 ie:

T T ORNE Y3 Patented Nov. 7, 1939 INTERNAL COMBUSTION ENGINE Carl voorhies, Detroit, Micln, assignor to Eaton Manufacturing Company, Cleveland, Ohio, a

corporation of Ohio ApIfliuflMLADl-il 14, 1938, Serial No. 202,022

7 Claims. (01.123-90) This invention relates to internal combustion engines and more especially to hydraulic, self compensating tappets for the valves of such engines, as well as to the initial and operating 5 supply of liquid medium for such tappets.

The principal object of the invention is to improve the art of internal combustion engines.

Another object of the invention is to provide an improved liquid supply system for hydraulic,

l self compensating tappets of an internal combustion engine.

A further object is to provide a liquid supply system for filling tappets with liquids. and expelling air from such tappets when the engine i is conditioned for operation.

Another object is to provide a novel type of hydraulic, self compensating tappet for internal combustion engines.

A further object is to provide a novel method of sealing a separate cylinder of a tappet plunger with reference to the tappet body to prevent leakage of liquid between such elements.

A still further object is to provide a self compensating type of hydraulic tappet of such a design and with parts so proportioned that the tappet will not elongate and follow an engine valve to such an extent as to cause breakage of the engine cylinder head, the engine valve, the tappet, or similar parts, in the event that a sticking condition of an engine valve occurs or an engine valve spring becomes broken or disabled.

Other objects, features and advantages will become apparent from the following description and appended claims taken in conjunction with the accompanying drawings, in which:

Figure 1 is a central longitudinal section of an internal combustion engine with portions broken away to show parts in elevation and depicting the arrangement of tappets for the engine valves and the arrangement of a liquid supply system for such tappets;

Fig. 2 is an enlarged transverse and vertical section taken through a portion of the engine shown in Fig. 1, such section being taken centrally through an engine valve and its tappets and showing certain parts in elevation;

Fig. 3 is a further enlarged section of the, tappet such as shown in Figs. 1 and 2, the section being taken on the line 3-3 of Fig. 2; and

Fig. 4 is a section taken onthe line 4-4 of F18. 3.

According to one aspect, the. invention involves v a liquid supply system for the valve tappets of an internal combustion engine, which system insures a supply of liquid to all of the tappets during operation of the engine and insures filling of the tappets with liquid medium and purging the tappets of air when the engine is initially conditioned for operation, or conditioned for operation 5 after a long idle period.

According to another aspect, the invention involves a novel construction of tappet which in conjunction with the above indicated liquid supply system insures an effective seal between the 10 separate cylinder of a tappet and a tappet body without requiring extremely close fit and polishing surfaces of such elements. The design of the tappet also insures purging the same of air or gas during engine operation, or while conditioning 16 the engine for operation, and at the. same time prevents tappets from following a stuck engine valve, or from following an engine valve in the event that its valve spring becomes broken or disabled. 1

For the purpose of illustrating the genus of the invention, a typical concrete embodiment of an, internal combustion engine is illustrated in Fig. 1 and comprises an engine block it having a crank case pan Ii and a cylinder head I! bolted there- 25 to. The flywheel housing l4, and the gear housing l5 are also bolted to the engine block Illand crank case pan II. The crank shaft I6 is jour- -naled for rotation in a front main line bearing ll andarearmainlinebearing l8aswellasin 30 an intermediate main line bearing 20, the latter being indicative of any desired number of intermediate bearings, th e number employed being mainly dependent upon the number of cylinders provided in the internal combustion engine. A 35 cam shaft 2| provided with valve lifting cams 22 is journaled for rotation in a front bearing 23' and a rear bearing 24. Connecting rods -25'operatively join the crank shaft [6 with pistons 26, which are disposed in the cylinders 21. A pair 0 of intake and exhaust .valves 28 are provided for each cylinder 21 and such valvesare normally biased into contact with their valve seats 3| by the engine valve springs 32, except when such 'engine valves are raised from their valve seats 3| 5 by the cams 22.

The engine block I0 is provided with a longitudinally extending'portion 33 which in the illustrated embodiment is provided with a. plurality of borings 34 disposed vertically and in a so common plane as illustrated in 1', for the reception of the engine tappets 3i. The-lon itudinally extending portion 33 of the en ine block II is also provided with a longitudinally extending boring I8 interconnecting all of-the vertical- 5 ing flbeing clwed by a plate 31 bolted to engine block ll along with the gear housing I! andtherearendoftheborlng being closedby the flywheel and clutch housing II. An oil pump it draws oil through the suction pipe II from thecrankcaseoilpan llandexhaustsoilthrough an outlet II which leads into the front main line hearing I! for the crank shaft l6. The'pump llisdrivenbyagearfl whichmesheswithsgear flflxedtothecrankshaftllandthelatteralso drivesagearllkeyedtothecamshaftfl. A

' passage 45 connects the front main line bearing 1 longitudinal boring it which several tappets II.

ll to the front bearing '23 of the cam shaft-2| and a H e 46 connects the bearing 23 to the supplies oil to the Adjacent its rear end, the longitudinal .ttisconnectedbyael'ltotherearbearing' 24 and it forthecamshaft lnected by means of a .a;

II forthecrank shaftil andthis'bearingiscone 48 to' the rear main linebearing ltforcrankshaft ,theoildumiiing from hearing l8 back into the crank case pan ll. Themovementofoiliromthecrankcase pan ll tothepurap38,throughthefrontbear'- ings l'l andflfor'ihecrankshaftandcam shaft, t rouehthetappets 35 throueh h plyinsage 3t therefor, and through the rear bearings and crank shaft, is indicatedbythearrowsil.

At some point adjacent the forward end of the longitudinal e 38 or within some passage commlmicating therewith. provision is made for injecting from a point exteriorly of the engine, oil under a pressure of eigh pounds per square inch, ormore, for the purpose of fllling the tappets 35 with oil and expelling air therefrom. Any suitable connection may be employed for this purpose However,inthepresentinstancethisis preferably eifected by means of a conduit and one-way valve I provided at the outlet side of the pump 38 adiacent the ll, the conduit extending to apoint on the exteriorof the engine for ty. Adjacent the rear end of the Jlongitudinally extending SI .a pressure relief valve 52 is provided.

'lhisvalvepreferablyconsistsofaflttlngfl threfldedtothe ensinemock ll-andprovided with aninteriorcylinderllinwhichaslidablyreceivedpistonii'isnormallyurgedbyaspring elI'ex.--

I. into a position to close a vent w: tendingthroughlawallofthefitting l3. Acap memberflisthreadedontheiittingltandmay be employed for the tension of spring It. 'f'hepurposeof this pressure relief valve I2 willbedescribed at alaterpoint,.andaccessmay behadtothisvalveuponremovalofthe inspection plate indicated at CI in Fig. 2.

Referencemaynowbeh'adto1='igs.2,3 and! which depict the construction of the preferred form-of tappet employed. The tappet 3 comprisesabodyportion II whichincludesatubular element of medium tappet steel or steel alloy machined t'o'the form indicated in Fig. 3 and a hardmetalcam 1:. :discflweldedthereto. The tubularbodyfl, priortothe welding of the discfltheretoisdrilledfromtheiowerendto providethe enlargedbore t3, the tapered bore-8i, andasmallercentralbore i l. flhetubularporticnllisalsoboredfromtheoppositeendto provide a-la'rge bore 1 of essentiallythesame diameteras the enlarged bore i3. tely midwaycfitslength, the tubular portion of bgdyll is'providedwlthaperipheral groove "to w l iilyoilorsimilarliquidmedimrifromthelongitudinal e 38 to the interior of the tappet through-a boring II, In drilling the boring I, a square cut shoulder 12 is provided in the tubular portion 62 of tappet body-ti and a recess I3 is countersunk outside the shoulder 12.

Referring more especially to gigs. 3 and 4, the

arrangement of a self compensating unit I4 ispensating unit to bedropped into the tappet body.

The separate cylinder unit I! is'provided with a cylindrical bore 'l'l in which the plunger "It makes a close but sliding fit so that there will be the proper leakdown rate between the periphery of the plunger and the bore ll in which it is received. A plunger spring 80 frictionally contracts-and engages at its upper end with the,

head portion of the plunger I8 and expands at its lowerendinto a notch 8| provided'at the upper end of the separate cylinder 15. The head portion of the plunger I8 is cut away as indi cated at If to prevent interferencewith the spring I, and to provide s. shoulder 83 engage- .able with the lower coil of spring 80 which frictionally engages the notch 8| to prevent excessive extension of the plunger 18 outwardly. from the separate cylinder 15. The lower end of the separate cylinder element 15 is of reduced diameter as indicated at 84, and in a reduced diametered bore thereof are press fitted a valve seat insert and suction tube 86 and a-valve retaining cage 81. A ,ball check valve 88 is assembled within the cage 81 and restricted there--v by to -limited mov'ement relative to-the valve seat insert '6. The valve retainer or cage I1 'is perforated as indicated at 80 to'permit upward movement-of liquid therethrough.

' The enlarged boring 63 at the lower end of the tappet body I and the beveled passage 65 constitutes a reservoir or oil supply chamber from the lower end of which oil may be drawn upwardly through the valve seat insert and suction tube 86, past the check valve 88 and through the valve retainer cage 81 into a hydraulic compression chamber ll as the'plunger II is extended outwardly relative to the separate cylinder It under' the influence of spring... This permits 7 the self compensating unit to maintain a no clearance relation between the engine valve 28 and the upper end of the plunger." under decreasing temperature conditions of the engine and as the valve 28 and engine block ll contract.

During increasing temperature conditions of the engine block and engine valves l0 and 28, pressure on the upper end of the plunger causes a slight leakage between the plunger I8 and the bore Tl permitting the tappet to contract to compensate for elongation of engine valve and engine block. As the engine valve 2. is lifted by the cam 2|,'-pressure on the upper end of the plunger It increases the pressure upon the oil within the hydrauliccompression chamber and forces the check'valve. ll against the valve seat insert It to maintain the plunger II in the desired adjusted position. The check valve 88 normally seats under the influence of gravity against the valve seat insert it except as it is lifted from its seat because of vacuum conditions created within the hydraulic compression chamber I as the spring 80 causes outward movement of the plunger I8 relative to the separate cylinder I5. Asqireviously indicated, no attempt is made to efiect a close fit between the outer periphery of the separate cylinder 15 and the boring 66 so that oil could leak freely therebetween except as checked and sealed by engagement of the supporting and sealing flange I6 on the square cut shoulder 12 of the tappet body 6|. The flange I6 and square cut shoulder 12 provide an upper end suspension means for the self compensating unit 14. The provision of the ffange I6 and square cut shoulder I2 provides a far more effective seal than would be possible if attempt were made to effect a close flt and polished cooperating surfaces between the periphery of the separate cylinder 15 and the bore 66.

Referring to Figs. 2 and 3, it will be noted that the flange 16 is spaced from the wall of the bore 61 so that no oil sealcan be effected between the periphery of flange I6- and the wall of bore 61. This spacing of the flange I6 relative to the wall of the boring 61 prevents the liquid supplied from the normal lubricating system of the engine. from lifting the self compensating unit by force applied to an effective area greater than that of the central portion of the separate cylinder unit I5. If the flange I6 were large enough to make a close fit with the wall of bore 61, it would increase the effective cross-sectional area of the self compensating unit to an area approximately equal to that of the bore 61. This would make itmuch easier for the lubricant of the conventional lubricating system of an automobile to lift the self compensating unit. If, for example, it is assumed that a {6"- diameter plunger I8 is employed, and that the oil pressure of the engine-lubricating system does not reach a maximum of over fifty pounds per square inch, during normal operation of an engine, then the area acted upon by the oil pressure tending to force the plunger outwardly of the cylinder.- would be approximately of one square inch, and the plunger would tend to be forced outwardly by a force of approximately seven and one-half pounds. The lubricant under pressure would also tend to lift the self .compensating 1mit and would act upon a cross-sectional area approximately that of the bore 66 which would be about 0.277 square inches, but

since the pressure tending to force the plunger outwardly relative to the separate cylinder reacts to hold the separate cylinder in the bore of the tappet body, the maximum force tending to lift the tappet cylinder relative to the tappet body would be the product of the maximum oil pressure, for example, about flfty pounds per square inch, times the difference inarea of the separate cylinder and plunger which is approximately 0.127 or approximately a force of 6.35 pounds tending to push the self compensating unit out of the bore of the tappet body. Thus within the operating range, a. seven-to ten pound plunger spring 88 would hold the self compensating unit in the bore 66 against the pressure of the oil in the lubricating systemof the engine. However, in the event of a stuck engine valve or broken or disabled valve spring, when the plunger 18 moves upwardly approximately of an inch from operating position, the bottom coil of the spring 80, which is frictionally engaged with the wall of the groove 8|, engages the shoulder 83 of plunger 18 which eliminates the effect of the plunger spring 88 so far as holding the unit in its cylinder is concerned and leaves the pressure of about 6.35 pounds tending to lift the unit out of the tappet body. Inas much as oil supplied to the tappet does not pass through any nonreturn valve except the check valve 88 and the plunger is prevented from moving outwardly by means of the plunger spring 80 and cooperable shoulder 83, the self compensating unit can be moved back rapidly into the tappet body with a.

. valve or broken or disabled engine valve spring.

The beveled passage 65 facilitates escape of air from the reserve chamber provided by this beveled passage and the enlarged bore 63. The air can flow upwardly through the beveled passage 65 and the clearance between the periphery of the separate cylinder I5, and the wall of bore 66, and escape between the supporting shoulder I2 and flange 16 particularly during the period when the cam 22 is not elevating an engine valve When initiating operation of a new engine or conditioning an engine for operation after a long idle period, it is desirable to expel all air from the tappet-and fill the reserve chamber provided by the enlarged bore 63 and beveled passages 65 as well as the compression chambers 9| of the tappets with'oil which is free from air.

Referring also to-Fig. 1, oil under a pressure ofabove eighty pounds per square inch for tappets equipped with a seven to ten pound plunger spring may be injected into the lubricating system ofthe engine by means of the conduit and check valve 5| provided in conjunction with the pump 38 as indicated in Fig. 1. Injection of oil at a pressure above eighty pounds per-square inch would lift the self compensating unit relative to the tappet body to break the seal between the shoulder I2 andflange 16 permit-ting the with oil from the conventional lubricating system of the engine. During the injection of such oil under high pressure into the lubricating system for the purpose of filling the tappet, it is noted that the inspection plate 68 would be removed and that either the vent 51 of pressure relief valve 52 could be closed or a solid piece or heavier spring substituted for the spring 56 thereof. This would insure, delivery of oil under high pressure to all of the tappets of the system. Once the tappets have been supplied with oil, the

pressure relief valve 52 is conditioned to act under the influence of its spring 56 which may be so adjusted as to such tension that it will relieve at a predetermined pressure and insure flow of lubricant to all of th'e tappets 86 and throughout the longitudinally extending passage 36. The bearings 24 and I8 will be supplied with oil under pressure, the maximum pressure of which will be approximately that predetermined pressure at which the pressure relief valve 52 is set to open. As-previously indicated, the cap I8 of the pressurerelief valve 52 may be employed for adjusting the pressure at which this valve will aflord relief. It is noted that the flow of oil through the cam shaft bearing 23 and passage 36 is ordinarily suilicient to supply drawings shall be interpreted as illustrative and not in a limiting sense.

- What is claimed is:

1. In an internal combustion engine, the 'combination with a plurality of hydraulic valve tappets, of an engine block provided with a like number of cylindrical tappet guide bores through a wall of said block and receiving said tappets,

said tappet guide bores having their axes extending in substantially the same direction and lying in a common plane, a straight line passage extending through all of said bores, a source of I liquid supply, a pump arranged between and communicating with said source of liquid supply and one end of said straight line passage for furnishing liquid to said tappets, and a pressure relief valve communicating with the other end of said straight line passage. V 2. In an internal-combustion engine, the combination with a plurality or; hydraulic valve tappets, of an engine block provided with a like number of cylindrical tappet guide bores through a wall of said block and receiving said tappets, said tappet guide bores "having their axes extending in substantially the-same direction and lying in a common plane, a straight line passage extending through all'of said bores, a source of liquid supplina pump arranged between and communieating with said source of liquid supp y and one end of said straight line passage for furnishing liquid to said tappets, and an adjustable pressure relief valvecommunicating with the,

in substantially the same direction and lying ,in 1

a common plane, a straight line passage extending through all of said bores, a source of liquid supply. a pump arranged between and communieating with said source of liquid supply and one end of said straight line passage for furnishing liquid to said tappets, 'a pressure relief valve communicating with the other end of said straight amass:

line passage, and an admission means adjacent said pump for supplying liquid at a higher pressure to said straight line passage than the pressure at which liquid is normally delivered to said p sa e by said ru p.

4. In a valve tappet of the hydraulic type comprising a tappet body having a bore closed at its lower end, a selfcompensating unit including a separate cylinder, plunger, and plunger spring, said unit being insertable into said bore, the boreofsaidtappetbodybeingenlargedatits upper end to provide a shoulder adjacent the upper end of said separate cylinder, and an-out-. wardly extending portion of the upper end of said separate cylinder adapted to engage the shoulder for supporting the self compensating unit. I

5. In a valve tappet of the hydraulic'type comprising a tappet body having a bore'ciosed at its lower end, a self compensating unit including a separate cylinder, plunger, and plunger spring, said unit being insertable into said bore, the bore of said body being enlarged at its upper end to. provide a shoulder adjacent the upper end of said separate cylinder, and an outwardly extending portion of the upper end of said separate g5 bore of saidtappet body being enlarged at its 3- upper endlto provide a shoulder adjacent the upper end of said separate cylinder, and an outwardly extending annular flange on the upper end of said separate cylinder engageable with the shoulder of said tappet body for supporting the self compensating unit, said flange being spaced fromthe wall of the enlarged portion of the bore at the upper end of said tappet body.

7. In a valve tappet of the hydraulic type comprising a tappet body having a bore closed at its lower end, a self compensating unit including a separate cylinder, plunger, and plunger spring,

said unit being insertable into said bore and terlminating in a reduced tubular portion at its lower end, the bore of said tappet being enlarged 50 at its upper end to provide a shoulder adjacent the upper end of said separate cylinder, an annular flange portion on the upper endof said *1 cylinder engageable with the shoulder of said tap t body for supporting the self compensating unit, said flange having its outer peripheral surface spaced from the wall of the enlarged portion of the bore and the upper end of said tappet body to prevent a sealing eiiect therebetween,

and the "bore of said tappet body being enlarged so .at its lower end to provide a liquid reservoir within the tappet body. r e V cam. voortmss.

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