US1872180A

US1872180A - Internal combustion engine

Info

Publication number: US1872180A
Application number: US303223A
Authority: US
Inventors: Julius C Peterson
Original assignee: Individual
Current assignee: Individual
Priority date: 1928-08-31
Filing date: 1928-08-31
Publication date: 1932-08-16
Anticipated expiration: 1949-08-16

Description

Aug. 16, 1932. c PETERSON 1,872,180

INTERNAL COMBUSTION ENGINE Filed Aug. 31, 1928 2 Sheets-Sheet 1 Fig.1

[n z/erzzor Aug. 16, 1932. c TER 1,872,180

INTERNAL COMBUSTI ON ENGINE Filed Aug. 51, 1928 2 Sheets-Sheet 2 [nvenlor Patented Aug. 16, 1932 UNITED T JULIUS .rnrnaspm or CHICAGO, 'ILLINQ INTERNAL mumm anoint:

Application filed Au ust 31,1928. Serial No. 303,223.

My invention relates to internal combustion engines of the tour stroke cycle type and particularly to those engines in which a t-uel mixture, formed outside the cylinder,

enters the cylinder through a valve and in which the products of combustion leave the cylinder through another valve. My invention relates particularly to-the valves, to the valve actuating mechanism, and to a cylinder it block and cylinder head adapted *to'the 11558 of the valves. The principal objeetsotmy invention are: first, to provide a valve which ofi'el's very little resistance to the =fiow of vapor or gas through its-second, to provide a valve which, vsfihen used .as an exhaust valve, requires less force tor-its opening than is required for the opening ot'the usualpoppet valve; third, to provide a valve-which, when used as an exhaust valve, does not over-heat; 2D fourth, to provide a valve and compression chamber such that the greater part of the volume of the compression chamber is contained within the cylinder proper; fifth, "to provide a valve actuating mechanism that is positive in action asto the closing of the valve; sixth, to provide a valve which automatically opens fart-her at higher engine speeds than ,it opens at lower engine speeds; seventh, to provide a valve which remains 59 open tor a relatively longer period at higher engine speeds than at lower engine speeds; and eighth, to provide adequate lubrication torthe bearings .ofthe-valve;

Another object oi my invention is to provide such positioning of the valves as will permit of their being of'maximum diameter tor an engine having cylinders of a given diameter and a crankshaft of a given length. Further objects of my invention are to accomplish "the foregoing objects in such a waythat no dihiculties of manufacture shall be encountered, that the mechanism sha l be durable, that it shall be easy of adjustment, and that it -shall require a minimum of care and attention to :keep it at maximum eiiiciency. v

Having stated in a general avayrthe principal features of my {invention and the advan tages to'be o'btained iii-omits use, 1 will now describe theapreferred QfOI'IIl'EtIlQl lIQ-Wit operates.

My invention is particularlyapplicable, to engines of thetype in most commonuse, that is, with a water cooling system and vertical cylinders. However, it is adaptable to engines having other cooling systems, such as Q air cooling, and to engines having inclined cylinders or with cylinders arranged radii-all-y. The limitation of my description to a single type of engine is not to be understood as limitingthe scope of my invention. Q The drawings are in the main illustrative, and other forms, coming within the scope of my invention, are practical and I do not limit my'invention to what is shown in the drawings. Figure 1 a vertical section through the engine on a plane containing the longitudinal axes of the cylinder and of the'exhaust. valve, the plane being normal to the axes of the camshaft and crankshaft, the piston and W connecting rod not being in section; the piston ascending on the exhaust stroke, the .exha-ust valve being open at its maximum and the intake valve being closed, the various parts being in the positions they take when the engine is running at its highest speed. Figure 2 is a top view of part of the cylinder head, the portion at the right being out awayto show ahor'izontal section on the pl ne 2 2 of Figure 1. Figure 3 is a top viewof part of the cylinder block with the cylinder head removed, the portion near the center-being cut away to show a horizontal section on the plane 3 301: Figure 1, andithe portion i at the right being cut away to show .a horizontal section on the plane 3 8 of Figure the valves not being-shown. Figure 411s aside view of part of the cam shaft. Figurefi is a top viewof the upper end of the valvestemi Figure 6 is a top view of the cupped washer which closes the upper part of the interior of the valve piston;

The cylinder head is substantially in the form of a rectangular block except for the Q5 reinforcement 1, which surrounds the openings-ofthe-exhaust passages 52 and the intake passages 3. The Walls 4 of the exhaust pas.- sages and the walls 5 of the intake passages, are formed integral with the rest of the-cylr 1 I plugs.

Theflower surface of the cylinder head is a plane, andthe lower ends of the spark plugs lie in, or substantially in, this plane, so that when the head 9 of the piston 10 ascends to its highest point on the exhaust stroke, the

clearance between the piston head and the cylinder head may be a minimum without any chance for the spark plug to be touched by the piston head. 7

Between adjacent gas passages, and also near the ends of the cylinder head, are holes 11 for bolts to hold the cylinder head in position. 7 The holes 11 accurately register with thethreaded holes 12 in the top of the cylinder block, the threaded holes 12 receiving the threaded ends of the bolts which hold the cylinder head in position. Other holes 13, positioned in the ends of the cylinder head and along the side of the head opposite that containing the holes 11, are provided to receive other bolts for holding the cylinder head in position. The holes 13 accurately register with the threaded holes 14 in the top of the cylinder block, the threaded holes 14: receiving the threaded ends of bolts which hold the cylinder head in position. The hole 15 is an outlet for water of the cooling system, the threaded holes 16 being for bolts to hold the water manifold (not shown) in position. Holes 17 in the bottom of the cylinder head register with corresponding holes in the top of the cylinder block, providing passages for the cooling water from the cylinder block to the cylinder head.

This form of cylinder head is very simple to cast and to handle during machine operations, which are very few, keeping down the cost of manufacture. The gas passages are short and unobstructed. The spark plug wells act as reinforcements to strengthen the lead to withstand the pressure in the cyliners.

The upper part of the cylinder block is also substantially in the form of a rectangular block, andthe upper surface is a plane of the same over all dimensions as the lower surface of the cylinder head. The holes 18. register with corresponding holes in the bottom of the cylinder head, providing passages for the cooling water to flow from the cylinder block to the cylinder head. The usualgasket 19 is used to make a gas tight and water tight joint between the cylinder block and the cylinder head. i

The bore of the cylinders, formed by the cylinder walls 20, is of uniform diameter throughout its length, permitting the piston 10 to ascend to within mechanical clearance distance of the cylinder head, on the exhaust stroke, when the piston is of the type described in my application for Letters Patent, towhich the Patent Oiiice has given the fierial Number 288,150, series of 1925, and which was filed June 25, 1928.

A valve recess 21, connected with the bore of the cylinder, is formed in the top of the cylinder block. The depth of the recess is uniform and such that when the valve is open to its maximum, the top of the valve head 22 will be substantially-in the same plane as the bottom of the recess. The walls of the valve recess are formed to give smooth surfaces which will cause very little interference with the exhaust gas leaving the cylinder, and which will cause part of the fuel mixture entering the cylinder to flow around the exhaust valve piston, helping to cool it, and which will cause suflicient turbulence of the fuel mixture to insure the residual burned gas being thoroughly mixed with'it, so that combustion on the power stroke will be uniform. That part of the fuel mixture which flows around the exhaust valve piston, receives therefrom a certain amount of heat, which helps to vaporize any unvaporized fuel in the fuel mixture.

When the valves are closed, the valve pistons occupy a large part of the volume of the recess, and only the remaining part of the volume contains residual burned gas at the completion of the exhaust stroke. This remaining volume may be as small as three percent (3%) of the total volume of the cylinder. The bore of the cylinder is of uniform diameter throughout its length, and the closure of the upper end of the cylinder is parallel to the piston head when the latter is at the end of the exhaust stroke. This construction, in connection with a piston, such as referred to above, in which the head of the piston may be constructed with a two percent (2%) clearance volume, permits ninety-five percent (95%) of the products of combustion to be expelled from the cylinder on the exhaust stroke.

A shallow circular depression 23 is formed in the bottom of .the recess 21, the diameter of the depression being slightly larger than the over all diameter of the exhaust valve head 22, and the depth of the depression being such that suitable clearance will be left between the bottom of the depression and the lower exterior surface of the valve head, when the valve is open at its maximum. Another similar depression 24; is formed in the recess 21 for the intake valve. Concentric with the depression 23, the cylindrical exhaust valve well 25 is formed in the cylinder block, the walls 26 of the well being an integral part of the cylinder block. The exhaust valve piston is positioned in this well, and intake valve piston is positioned in the similar intake valve well 27, which has the walls 28, also formed integral with the cylind-er :block The bottom .OfE each valve-well is cl-osed bya removable screw plug 29', which isiscrewedjnto. a: threaded hole formed in the bottom of the well. In the center nfthe plug ran sli ding iitwiththe valve stem 30,.

i'llhe exhaust waive; wellx is surroundedhy the water. of the cooling system. 'Jlhe intake valvewell .is similarlys-urrminded by water except zfor. a short distance where the well twalland the cylinder wall unite IliElOHdQlfililltth thejintake v'alveanay "be positioned :as'closelv as possible to the cylinder. A slight reducan fatlle tdiam'etercf (either one :or: both -0fi13lf1'0SEEDlVES will .perinitiithc intakeval-ve well-to bepositioned' so thatrit mayibe entirely -'surronnded lay-water, whenthislisdesired;

Elie-positioning of thevalve wells in pairs, eachwpair on a iineidiagonal to theiplane containing thelong'itudinalaxes of the cylinder permits the'valvesllto he of-largediameter without interfering with :the adequate cooling of the valve wells and with the distancebetween cylinder centers :kept at: a minimum.

.filhe threaded hole 31 is provided tormaking .a:connecti;on' with. the oiling system wso that lubricating oil willrbessupplied to the wezxhaust ".valver'welltbyithe oil passage 32a-nd .to' tlrelintakevalve wel lz'by'itheoi-l passage l'lhe outlet-oil passage 34 provides for the escape of surplus oil "fromLth-e exhaust valve- Well .to the-space 'centairnng the push rod-'85. The outletrdilmpassage, 36 performs thesamei function for: the intake valve well. iTihe oilithat passes throughitheroiitlet oil pas sages :collectsiin thezdepression tormed on top ofthe crankcasegwhere the bearings :87 zof the push rodszare formed, providing-lubri icationtor these ibeanings. VThe ,oil'lcaves [the depression throng-lithe holew3'8 in the top of the crank case, lubricatingtheparts: of :the valve actuating :mechanism "which areepositioned within the crank-case. The cover 739 skeepsthecil from splashing out and prevents rgetting int-oithe oil. An adequate supply of oil is thus pnevided forzthe en tire' system :of valves and actuating mechanism.

Thecranlr caseis formed integral with the rest of the cylinder :hlock,- with the walls 40,

the tra-nsoms 41 in-which the shaft 42 is pos'iti'oned, and the projectingblocks l?) in which the bearings for the camshaft 4a are positioned. This construction provides a "casting which '"be readily "manufactured, "and the machine work required on it is simple and not of large amount.

.fIhe exhaust valve proper consists of two .main parts. One of these is the. valve .piston, cons isting of the circular valverheadQQ which has: the conical suriace 45 adapted -=.to. fit the :conica-lival-ve seat 16. termed in the cylinder head: at. the entrance to 'theezahaust passage 72, and the cyli-ndrica l skint .47., which has piston ring grooves formed its exterior surssdfaaceto accommodate the piston rings 4C8 of e the usual form. I

vct the conicalvalve seat, so that when'the valve is closed, thepressure in the cylinder on the compression and power strokes will act on the-lower surface of the valve head and ten-d to keep it closed. However, thee-it'- fectivc area against which the pressure acts isre-la-tively small, so that on the exhaust stroke, when the valve must be opened against the pressure in the cylinder, the pressure does notinterfere with the opening of the valve. s

The distance of the upper piston ring below the valve head is such that the ring will not-quite reach the top of the valve well in which the piston has a sliding t, with the necessary clearance allowance for expansion, when the valve is closed. The piston rings, in connection with the oil-supplied for lubricating the valve, form a gas tightseal ?between the valve piston skirt and the 'borepf the valvewell. i The lower inner surface of the valve piston skirt has a female screw thread 49 to re-' ceive a corresponding male screw thread on the outer cylindrical surface of the retaining,- ring 50. The retainingring has an ill-{Q .ncr cylindrical surfaceto form a slidingiit I with the corresponding cylindrical suriace of .the head 51 of the valve stem 30, which is the other main part of the exhaust valve proper. The retaining ring has an annular 3W groove 52, the bottom of the groove being substantially of semicircular cross section, and .the inner wall of the groove being slight- 1y inclined to form a substantially conical surface, making the groove somewhat-wider at the top than at the bottom. Thelowrer portion of the valve stem head 51 is formed into anannular ring53, adapted to enter the groove 52, with a variable clearance between the ring and groove, provided by the "incl nation ofythe inner wall of the groove; i

The groove 52 and the ring 53, together with the oil which enters the groove from the supply in the bottom of thevalve well, form a dashpot -to-absorb the momentum of the valve piston when the latter is about to reach the limit of its upward motion as the valve closes. I

54 is a compression spring whichhas one end bearing against the valve stem head 51, and the'other end bearing against the cupped washer 55, which is seated against the shoulder 56 formed on the inner surface of the valve piston skirt. [is the valve piston is capable of a limitedmotion relative to the valve stem head, in the direction of the axis of the valve, the valve spring, which is at all times under compression, tends to move the valve piston upward relative to the valve stem vhead; s

The cupped Washer fits closely against the shoulder 56, forming therewith, when supplied with oil from the supply in the valve well, an air tight seal. The notches 57, in the outer circumference of the cupped washer, permit the escape of air from the closed chamber thus formed in the upper end of the valve piston, when the rise in temperature of the air therein, due to the heating of the valve, causes the pressure in the chamber to reach a point where it is greater than the pressure of the valve spring. The holes 58 in the valve stem head ermit the assa 'e 'of air through them, so that the air pressure is always the same on both the top and bottom of the head and the movement of the valve stem is not affected by the air pressure 34, are just below the lower edge of the valve piston skirt When the valve is closed. As the valve opens and the valve piston descends, both openings are closed. hen the valve is closed, then, since the oil outlet passage 3% is open to a chamber where the air pressure is that of the atmosphere, the level of the oil in the bottom'of the valve well will be approximately even with the openings of the oil passages, and the pressure of the air'in the chamber will be that of the atmosphere. When the valve is open to its maximum, the volume of the chamber available for containing air may be as small as one third the volume available when the valve is closed. The corresponding increase in air pressure not only absorbs the momentum of the valve piston, bringing it quietly to rest, but greatly assists the valve spring in starting the valve piston upward on the closing part of the valve cycle. This relieves the rest of the actuating mechanism from much of the hardest part of its work, that is, stopping the downward motion of the valve piston and starting its upward motion.

This feature of my invention makes it practical to use a much lighter valve spring than Would otherwise be required. As the inertia of the air is very small compared to that of springs, the response is much quicker and the lag of the motion'of the valve piston behind the motion of the valve stem, on the closing stroke, can be varied by varying the capacity of the air chamber, so that the valve timing at high speed will be just that required for the best results, at the same time that the valve timing for lower speeds also remains correct. The rest of the actuating mechanism may also be made lighter, and as it does less work and therefor gets less wear, its durability is increased.

The retaining ring 50 permits the various 5 ,parts contained in the valve piston to be that ring to form the connection between the valve piston and valve stem, necessary to cause the valve to open when the valve stem descends;

The lower end of the valve stem has a male H screw thread 59 adapted to fit a corresponding female screw thread on the interior of the upper end of the hollow push rod 35. The lock nut 60 prevents any change in the adjustment of the distance between the bottom which in turn bears against the shoulder Get on the push rod. The upper end of the spring ears against the plate 65, which is held in fixed position by bolts (not shown) which press it down against the top of the cylindrical spring housing 66. The push rod spring is always under compression and causes the bottom 61 of the push rod to maintain constant contact with the end (37 of the 61 of the push rod and the lower surface of the annular rings 53, without loosening this cam lever 68. The other end of the cam lever V is hinged to the crank case by the shaft 42. The cam roller 69 is positioned in a slot in the cam lever, and rotates on the hollow pin 70 which is seated in the sides of the slot in the cam lever. The downward pressure on the end 67 of the cam lever causes the cam roller 69 to maintain constant contact with the surface of the cam 71 which is formed on the cam shaft 44, revolving at half the speed of the crank shaft, through the means of gears or a chain, in the usual manner.

The cam lever for the intake valve is similar to the one for the exhaust valve except that it is longer so as to reach the bottom of the push rod 73 for the intake valve. for the intake valve will have less eccentricity than the cam 71 for the exhaust valve, due to this difierence in length of the respective cam levers. Both cams, however, are circular for the greater part of their contour, with the centers of their circles lying in the axis of the cam shaft. The portions of the contours hav ing reduced radii govern the opening and closing of the valves, while the circular por- The cam Tet tions maintain the valves in their closed positions. The cam shaft has the cylindrical bearings '15-, otslightly greater radius than thema ximum radiusofi thecams. c The f intake valve is similarin, construction tetheexhaust valve. I The other necessary parts, of theengine, not particularly designated, and whether shown. inthe draw. or not, are assumed to be present and may beof any usual construction,

In the operation of an engine equipped with my invention, the exhaust valve, from the time it closes at the end of an exhaust stroke until it opens again at the of other exhaust stroke, is kept closed byv the high part of the exhaust cam being in contact with the cam roller, causin the, cam lever, push rod and valvestem all to take their highest positions, with. the push rod spring compressed to its maximum, and the valve piston held in its highest position by the pressure of the valve spring, so that the conical surface on the valve head fits closely intothe conical valve seat in the'cylinder head. The upper part of the valve piston occupies apart of the volume of the valve recess, The valve spring is more than strong enough to keep the valve closed during the intake stroke while the pressure in the cylinder' is less than atmospheric pressure.

.lQuag'ing the compression and power strokes the pressure in the cylinder presses equally on every point in the cylindrical surface of the valve piston exposed in the valve recess,

so that there is no tendency for one side of the valve piston to press against the bore of the. valve well more than any other side. Nor is there any tendency to push the valve head out of the valve seat. The lower surface of the valve head, between the outer surface of the valve piston skirt and a circle of the same diameter as the larger circumference of the valve seat, is theeiiective area acted onby the pressure of the contents of the cylinder, tending to press the valve head upward into its seat. This area is about of the eiiece tive area acted on by the pressure in the case of an ordinary poppet valve of equal diameter, so that the effective pressure is'about 30% of that acting on an ordinary-poppet valve.

As the ordinary poppet valve used as an exhaust valve gets very hot, particularly if the engine is run continuously toria long period, and the pressure is high, there is a tendency for it to stick in its seat. This sticking, to

- gether with the fact that the pressure on the valve head must be overcome in order to open the valve, requiresthe use of considerable power to open the valve. it is, therefore, not practical to open the valve byspring pressure, as the spring'w'ould have to be too strong in order to insure opening. Consequently the valve must be opened by the cam and the spring'must bevelled-upon to close the valve. This results in inaccurate closing at high. speeds,d.ue to the inertia ofthe moving. parts. In my invention the valve is opened by a spring, so that the closing is accomplished by the cam action and is thereforepositive, nomatter what the speed, of the engine may be. The pressure. on my valve being about less than that on the ordinary poppet valve, permits the use of a spring foropening the valve, particularly since my valve does not stick in its seat. a The area of thevalvepiston exposed to the heatof the contents of the. cylinder during power stroke. is approximately equal to the area of the valve head of. an ordinary poppet valve of equal diameter. The latter has the valve seat and valve guide to carry off the heat, and the mass of the heated metal is probably somewhat greater than in my valve, which has, a similar valve, seat and the relatively great area of water cooled valve well to carry off the heat. Moreover, the average distance which the heat niust travelto reach. a. cooling surface in the ordinary poppet valve. is much greater than the average dis tance the heat must travel in my valve. Dur ing the power stroke, therefore, my valve will remain much cooler.

As the piston nears the lower end ofthe power stroke, the lower part of the exhaust valve cam comes into contact with the cam roller and the push rod spring causes the push rod and valve stem to start to descend. Thedashpot, which is slightly open while the valve is closed, closes and the valve piston starts downward, opening the valve. head of the valve becomes exposed to theexhaust gas, but on only the upper side, while the area of the valve piston skirt exposed to the exhaust gas is decreased as the valve piston descends, this area being brough into contact with the cooling walls of well. When. the ordinary poppet exhaust valve is open, both sides of the valve head and a considerable portion of the valve stem are not only exposed to the exhaust gas, but are in the very center of the flow of the gas, the exposed area being more than double the exposed area in my valve. No part of myvalve is 'n the direct path of the gas leaving the cylinder, and the gas leaves with a lower 7- velocity, as it has a larger opening, with no obstructions in it, throughwh ch to pass.

I The part-of my valve which is exposed to the'heat of the cylinder contents during the power stroke is being cooled during the exhaust stroke,-while in the case of the ordinary poppet valve, lb is not only not being cooled at any point except the valve stem, and very poorly there, but it is much'more exposed to the heat of the exhaust gas. On

tlze exhaust stroke, therefore, my valve will remain very much cooler; This is particularly so, also, because the head of myvalve, having to withstand only the relativelylow pressure of the exhaust gas, can bemade very 9 the valve 1 i much lighter than the head of an ordinary poppet valve which must withstand the'relatively high explosion pressure. Consequently the heat will be carried away from the the oil inlet passage.

smaller mass of metal much more quickly.

The ordinary poppet valve cannot be cooled to any considerable extent by the incoming fuel mixture. On the contrary, it is very simple with my valve, to direct part of the fuel mixture entering'through the intake valve, in such away that it will flow around the exhaust valve piston, both cooling the valve and warming the fuel mixture.

WVhen the engine is running at low speed, the dashpot remains closed and the valve piston and valve stem move as a unit, the pressure of the valve spring and the pressure of the air in the chamber at the bottom of the valve well being sufiicient to overcome the momentum of the valve piston before the dashpot can open. The valve therefor opens a distance corresponding to the eccentricity of the cam. As the cam rotates farther, it forces the cam roller up and the valve closes, the dashpot opening sli htly and the valve spring being compressed slightly more. At low speed, then, the valve is firmly seated and is firmly held in position in its seat.

When the valve is closed, the openings of the oil inlet passage and of the oil outlet passage are open. Oil from the oiling system enters the bottom of thevalve well through If the level of the oil in the valve well is below the opening of the oil outlet passage, no oil passes out and the incoming oil continues to raise the level of the oil. WVhen the level of the oil reaches the opening ofthe oil outlet passage, enough oil passes out through that passage to keep the oil level at approximately the level of the oil passage openings.

As the valve opens and the valve piston descends,.the openings of both oil passages are closed by the lower part of the valve piston skirt. The entrance of the lower part of the valve piston skirt and retaining ring into the oil, raises the oil level. At the same time the cupped washer is descending, so that the volume in the chamber available for the air is reduced. and the pressure of the air is increased. This air pressure forces some of the oil up between the valve piston skirt and the bore of the valve well, lubricating the valve piston and piston rings and making a gas tight and air tight seal between the valve piston and the bore of the valve well. A little of the oil is forced out through the oil passages and a little through the bearing of the valve stem in the bottom of the valve well, but the total amount is small and the effect on the air pressure in the bottom of the valve well is negligible. The lubrication of the valve is very positive and thorough.-

As the speed of the engine increases, the

. velocity of the valve piston increases and the momentum of the valve piston increases as the square of its velocity. Above a certain engine speed, then, the momentum of the valve piston. will overcome the pressure of the valve spring and the pressure of the air in the bottom of the valve well.

Consequentlythe distance which the valve piston descends will be greater than the distance the head of the valve stem descends, the valve will open wider and the dashpot will be opened. The higher the engine speed and the greater the momentum of the valve piston, the farther the/latter will descend, although, as the valve piston descends farther, the space available for the air in the bottom of the valve well is further decreased and the air pressure increased, and the valve spring is further compressed, Hence, the increased momentum and increased movementof the valve piston is met by increased resistance.

The strength of the valve spring and the volume available for the air in the bottom of the valve well may be so adjusted that, at the maximum speed of the engine, the valve piston will descend to a certain maximum distance which will leave proper clearance between the various parts, so that the bottom of the valve piston skirt will not strike the bottom of the valve well and the bottom the cupped washer will not strike the head of the valve stem.

The movement of the valve piston down ward, due to its momentum, occupies a short space of time during which the cam will have passed the position where its lowest point is in contact with the cam roller, and the latter will have started upward by the time the valve piston has been brought to rest. The approximate positions occupied by the various parts at this instant are shown in Figure 1.

Since the pressure of the air in the bottom of the valve well increases as the valve piston descends farther, and as the inertia of the air is very small, the valve piston is given a very strong upward push by this pressure, so that it starts upward much more quickly than it would were its initial impulse to come only from a spring.

Consequently, while the valve piston travels farther in less time at high engine speeds, it does so without any pounding and without any unduly high pressure on any bearing.

The design of the cam is such that the valve stem gradually comes to rest, while the air pressure, valve spring pressure and the momentum of the valve piston cause it to move faster, near the end of the closing stroke, than the'valve stem does. The groove in the retaining ring is filled with oil whenever the dashpot is open, and this oil is forced out of the groove by the ring on the valve stem head as the dashpot closes, bringing the valve piston to rest without shock, with the valve tween the valve stem and "push rod. Ti

1,172, ran

head seated inthe valve But it takes an appreciable time for the oil to escape from the groove through the narrow clearance between the inner wall ofthe groove and the ring the valve stem head, as the dashpot closes, so that the valve clos s a little la 1' would ii it were not for i than i the action of the da, pot. r

ice the action of a spring. 7

Provision has been made so that the valve may be adjusted. This is accomplished by means the screw thread connection b proper adjustment requires that the dashpot be slightly open when the valve is-closed, so that unequal expansion of the parts of the engine, as it gets bot, will not inter with the functioning o the valve. As cylinder lengthens, the .ive seat moves ward. The expansion of the valve ac 7 i sting mechanism is not likely to exactlycome pensate this c acement.

By unscrewing the screw plug in the botthe valve well a auge may be insert tom oi ed to ascertai: the position of the valvepliston at any pointofthe valve cycle. By ,7 in a bent \vire,rfcr instance, on the inner edge of the r raining ring, so that the mov ment of the .v

ind ate the mo'veme'ntofthe valve piston, the

combined length of the push rod and valve 1 stem ca be adjustedso that tl e valve stem v ll start downward slightly before the valve on. downwardas the valve opens, or so that the valve steinhas a slight motion upward after the valve piston stops, as the valve c oses. The valve is then in adjustment.

lock nut setting the adjustment is tightened, the "removed and the plug screwed cl; into its seat in the bottom of the valve well. i a

Since the valve is thoroughly lubricated anc since it stays cool and'will need to be ground in irequently, it will greqi ire very lll'ixile att tron, upkeep, and adjustment.

The u Qeration of the intake valve and its adjustment are sin lar to those'of the exhaustvalve. The intake valve cam is so formed as to cause the intake valve to open the exhaust valve has closed point, that is, when the engine is operated at highest speed. The time of opening of the valves is not cnanged by the speed of the engine, whilethe time of closing the valves is changed. The head of the intake valve is exposed to the'iuel mire ible part oi the wire will ture, but not to the v exhaust gas, so that the i 2.. En internal combustion engine,

valve comprising two main parts, said parts being connectedtogether-in such manner a to be capable of motion relative to eachother in the direction of the axis of said valve, and a spring adapted to limit said motion in one direct-ion, andto cause said motion in the op, pos-ite direction;

In an internal combustion engine, a

cylinder block, a cylinder formed in said cylinder block, a valve for said cylinder and an air chamber formed in said cylinder block, with air in saidchambeiythe construction of said valve and said air chamber being; such that theopeningwof said valve decreases the volume of said air chamber, increasing the air pressure opposing the motion of said valvegand the closing of said valve increases the volume or" said air chamber, decreasing the air pressure assisting themotion of said valve.

I 4-. In an, internal combustion engine, a 1 ve comprising two main parts, said parts ezng connected together in such manner as o be capable of a limited motion relative to aci other in the direction of the axis of said-valve, one or" said parts, comprising a circular head and aihollo-w cylindrical body,

and the other 01"- said parts comprising a valve stem witn a cylindrical head, said cylindrical respect to each other in the direction of the axis oi said; valve,-on e of said parts comprising acircularhead and a hollow cylindrical body, and the other of said parts comprising a valve stem with a cylindrical head, and dashpot'for limiting said relative motion and for transmitting motion from one of said parts tot-he other of said parts, said dashpot comprising an annular ring formed on said head of said valve stem, and an annular groove formed in a, retaining ring, said retaining ringbeing positioned within said cylindrical body. of the first mentioned of said parts, said groove being adapted to receive oil, and said ring adapted to enter said groove withavariable clearance bet-ween theside of said groove and said ring, all substantially as shown in the drawings and as described in the specification.

6. In an internal combustion engine, a valve comprising two main parts, said parts being connected together in such manner as to be capable of a limited motion relative to each other in the direction 01 the axis of said valve, one of said parts comprising a circular head and a hollow cylindrical body, and the other of said parts comprising a valve stem with a cylindrical head, and a dashpot for limiting said relative motion and for transmitting motion from one of said parts to the other of said parts, and a spring, said spring adapted to limit the relative motion of said parts and to transmit motion from one of said parts to the other of said parts, said spring being positioned within said cylindrical body of the first mentioned of said parts, all substantially as shown in the drawings and as described in the specification.

7. In an internal combustion engine, a cylinder block, a cylinder formed in said cylinder block, a cylindrical valve Well formed in said cylinder block, and a valve for said cylinder, said valve comprising two main parts capable of a limited motion relative to each other in the direction of the axis of said valve, one of said parts comprising a circular head and a hollow cylindrical body, said cylindrical body being positioned in said cylindrical valve well, and the other of said parts comprising a valve stem with a cylindrical head, said valve stem being positioned in a bearing in the bottom of said valve well, the bottom of said valve well forming an air chamber, one of said parts of said valve closing said air chamber in such manner that the.

opening of said valve decreases the volume of said air chamber, increasing the air pres sure opposing the motion of said valve, and

the closing of said valve increases the volume of said air chamber,decreasing the air pressure assisting the. motion of said valve, substantially as shown in the drawings and as described inthe specification.

8. In an internal combustion engine, a lubricating system for a valve and valve actuating system, comprising an oil inlet passage to a valve well, said oil inlet passage adapted for connection to an oil supply system, an oil outlet passage from said valve well, said oil prising a cylinder, a piston within said cylinder, and a. passage in communication with said cylinder, the combination therewith of a valve for opening and closing said passage, means including a cam for positively carrying the valve to a point adjacent closed position after which the momentum of the valve causes it to fully close, means for cushioning the seating of the valve, and means including a spring for opening said passage.

10. In an internal combustion engine, valve mechanism including a positive acting cam and a cushioning device for closing the valve, and means including a spring for opening said valve.

11. In an internal combustion engine of the type including a cylinder, a piston within the cylinder and a passageway in communication with said cylinder, the combination therewith of a valve seat in said passage, a valve having a head to cooperate with said valve seat for opening and closing said passage, said valve having a stem portion of slightly less diameter than the valve head and forming an annular surface parallel to the plane of the valve seat upon which the combustion gases may exert a pressure for maintaining said valve in a closed position during the power stroke of the engine, positive means for closing said valve and resilient means for opening it.

12. A valve mechanism for internal combustion engines comprising in combination a valve piston, a valve stem, means for actuating said valve stem, and resilient means for making a driving connection between said valve piston and said valve stem.

13. A valve mechanism for internal combustion engines comprising in combination a valve seat, a valve piston, a valve-stem, means for actuating said valve stem, means for driving said valve piston by said valve stem, and means for cushioning the seating of the valve in the valve seat.

14. A valve mechanism for internal combustion engines comprising in combination a" valve seat, and a valve cooperating with said valve seat, means for positively moving said valve into its seated position, spring means for moving said valve from its seated position, and means for cushioning the seating of the valve.

15. A valve mechanism for internal combustion engines comprising in combination a valve seat, a valve piston adapted to cooperate with said seat to close a passageway, a valve stem, means for actuating said valve stem in synchronism with the motor, and means including a spring positioned between the valve piston and the valve stem for automatically attaining a wider opening of the valve at high motor speeds.

16. A valve mechanism for internal combustion engines comprising in combination a valve seat, a valve piston adapted to cooperate with said valve seat for closing a passage- Way, a valve stem, means for actuating said valve stem in synchronism with the motor, a spring positioned between the valve piston and the valve stem for urging said valve piston into seated position, and means including a dash pot arrangement for unseating the valve.

17. A valve mechanism for internal combustion engines comprising in combination a valve seat, a valve for cooperating with said seat to close a passageway, said valve including a valve head and a valve stem, means for actuating said valve stem, and means intermediate said valve head and valve stem for cushioning the seating of the valve.

18. An internal combustion engine comprising in combination a cylinder, a piston within the cylinder, and a passage in communication with said cylinder, a valve seat in said passage, a valve having a head shaped to cooperate with said valve seat, said valve having a stem, said valve being arranged with respect to said cylinder so as to expose a portion of the valve stem to the gaseous mixture within the cylinder when the valve is in seated position, the exposed portion of said valve stem being of such diameter relative to the valve head so as to provide a relatively small area upon which the products of combustion may act to resist the opening of the valve, positive means for closing said valve and resilient means for opening it.

19. A valve mechanism for internal combustion engines comprising in combination a valve seat, a valve piston adapted to cooperate with said seat to close a passageway, a

valve stem, means for actuating said valve stem in synchronism with the motor, means including a spring positioned between the valve piston and the valve stem for automatically attaining a wider opening of the valve at high motor speeds, and means including a closed air chamber for increasingly cushioning the downward movement of the valve and for assisting the spring for starting the valve on its upward stroke at the said higher speeds of the motor.

20. In an internal combustion engine comprising a valve well, the combination therewith of a valve piston adapted to reciprocate therein and having an elongated skirt portion, a valve stem extending upwardly within the said skirt portion, a spring positioned within the piston and forming a driving connection between the valve stem and the valve piston, said valve stem having an annular depending rim for cooperating with an ihterior annular groove carriedby said skirt portion for forming a dash pot, and a plug closing the interior of said valve piston against the admittance of air.

21. An internal combustion engine comprising in combination a cylinder block, a valve well within the block, a valve piston adapted to reciprocate therein and having an elongated skirt portion, means for actuating said valve piston including a valve stem, extending within said piston and having, a driving connection therewith, means 'for lubricating said piston including a lubricating port adapted to admit a lubricant when the valve is in seated position but not be,- ing in communication with the interior of the piston when the valve is in unseated or closing the interior of said valve piston against the admittance oI air, and means for lubricating said valve including a lubrieating port adapted tocommunicate with the interior of the valve piston when the valve is in closed position; 23. In an internal combustion engine com- .prising a valve well, the combination therewith or a valve piston adapted to reciprocate therein andhaving an elongated skirt portion, a valve stem extending upwardly within the said skirt portion, a spring positioned within the piston and forming a driving connection between the valve stem and the valve piston, said valve stem having an annular depending rim for cooperating with an interior annular groove carried by said skirt portion for forming a dash pot, a plug closing the interior of said valve piston against the admittance of air, and means for admitting oil for forming an air seal between said piston and the valve well.

24. in an internal combustion engine comprising a valve well, the combination therewith of a valve piston adapted to reciprocate therein and having an elongated skirt portion, a valve stem extending upwardly within the said skirt portion, a spring positioned within the piston and forming a driving connection between the valve stem and the valve piston, a cup-shaped member arranged to form an air chamber in the upper portion of said piston, means for relieving the pressure in said air chamber, said valve stem having an annular depending rim ilor cooperating with an interior annular groove carried by said skirt portion for forming a dash pot, and a plug closing the interior of said valve piston against the admittance of air.

25. An internal combustion engine comrisin in combination a valve well a valve p b 7 piston within the well, a valve stem extending upwardly through the base of the valve well into the said piston, said valve stem having a driving connection including a spring with said valve piston, a closed air chamber formed between the base of the valve well and the valve piston, and means for creating a pressure within said chamber for assisting the action of the spring in driving said piston.

26. A valve mechanism for internal combustion engines comprising in combination a valve head and a valve stem, means for actuating said valve stem in synchronism with the motor, a spring positioned between the valve head and the valve stem for urging sa-id'valve into a closed position upon a given movement of the stem and for cushioning the movement of the head when the stem is moved in the opposite direction.

27. In an internal combustion engine of the type including a cylinder block, a cylinder within the block, a piston adapted to reciprocate within the cylinder, a cylinder head having a passage communicating with the cylinder, a valve seat in the head, a valve Well in the block in axial alignment with the valve seat, a valve in the well adapted to open and close said passageway, positive means for moving the valve to seated position and resilient means for withdrawing the valve, said valve being arranged to provide a clear and unobstructed passageway when said. valve is in open position.

JULIUS C. PETERSON.