Патент USA US2112045код для вставки
l March 22, 1938. g 2,112,045 s. R. PUFFER SEAL-FOR COMBUSTION ENGINES Filed April 3„ 1955 Figi 50 36 49 ' » zo \ 50a ’ . l5 ï `l7 55 | »a u '4 v «5 invento@ `Sammel RPuffeF, , b5 His Attow?eg. Patented Mar. 22, 1938 y 2,112,045 'UNITED' STATES PATENT OFFICE 2,112,045 VSEAL FOR. COMBUSTION ENGINES Samuel VIt. Puiïer, Saugus, Mass., assignor to General Electric Company, a corporation of New York Application April 3, 1935, Serial No. 14,433 1 Claim. (Cl. 286-27) The present invention relates to combustion engines, more specifically to the arrangement of The arrangement shown by 'way of example in valve means for controlling the flow of exhaustA the drawing comprises al combustion engine hav or combustion gases from a combustion chamber 5 or cylinder to an exhaust conduit or manifold. The usual arrangement includes a valve casing, a valve with a stem slidably disposed in a channel of the valve casing and a disk secured to the stem and in cooperative relation with an opening of the. 10 cylinder. The valve is operated by means includ ing a rocker arm disposed in a rocker arm box. In general practice mosphere or into a conduit or exhaust manifold, 15 the pressure in which> is substantially equal to that of the surrounding atmosphere. At times, however, itbecomes desirable to utilize available mosphere. Under such conditions’of increased back pressure it has been observed that the ex with an inlet or suction conduit I3 and an outlet or a discharge conduit I4. The latter fprms‘an air duct to an inlet I5 of a second stage. Inter posed in the air duct is a carbureter I6 in which the exhaust gases, after leaving this valve, are discharged directly to at energy in these exhaust gases in a turbine wheel, a waste heat boiler, or by other means. The 20 mostveiîìcient utilization of this energy requires that the pressure in the exhaust manifold be ap preciably higher than that of the surrounding at ing a casing I0 to which is ñanged a casing II of a supercharger. The supercharger in this par ticular instance has two stages, a ñrst stage I2 fuel is mixed with the air discharged from the 10 ñrst stage and forced into the inlet I5 of the second stage. 'I'he second stage has an outlet Il which forms an intake for an engine cylinder I8. The engine cylinder I8 is connected to an exhaust conduit or manifold I9 in which the pressure is 15 maintained higher than that of the surrounding atmosphere. 'I'he ñow of combustion gases from the engine cylinder I8 to the exhaust conduit I9 `is. controlled by means including a valve mecha- ` nism 20. The mechanism, as shown in Fig. 2, comprises a valve stem 2I slidably disposed in a 20 sleeve 22 formed in a valve casing 23. The valve casing 23 in the present instance is integrally united with a portion of the cylinder I8. The 25 haust valves become overheated, the valve stems become pitted and scored and the life of the en ' lower end of the valve stem is secured to a valve tire valve structure and other parts cooperating disk 24, which latter is in cooperative relation 25 therewith is materially shortened. The principal with a seat 25 on the cylinder I8. 'I'he upper end of the valve stem 2I is engaged by a rocker arm 26 held on a fulcrum 21 and connected to cause of this difficulty is that with the constant 30 back pressure in the exhaust manifold higher than the surrounding atmospheric pressure, hot exhaust gases flow through the clearance space between the valve stem and the surrounding channel into the rocker arm box. This ñow -of 35 gases overheats the valve stem, prevents lubri cant from entering the space between the valve stem and the channel, and further tends to build up a pressure inside _the rocker arm box which causes expelling of lubricant from this box 40 through any opening, however minute. The object of- my invention is to provide an improved construction and arrangement of the type of combustion engi nes above specified to re duce the injurious elîects of exhausting into -a 45 manifold or other chamber wherein a relatively high pressure exists. For a consideration of what I believe to be novel and my_invention, attention is directed to the fol lowing description and the claim appended there 50 to in connection with In the drawing, Fig.the accompanying‘drawing. 55 1 is a somewhat diagram matic view of an internal combustion engine em bodying my invention; Fig. 2 is an enlarged detailA view of a part of Fig. 1, and Figs. 3 and 4 are modifications according to my invention. a push rod 28. The valve is normally biased towards closing position and held in contact with 30 the right-hand end of the rocker arm 26 by means of a coiled spring 29 surrounding the upper end of the valve stem 2l. The .latter and the rocker arm 26 are enclosed by a rocker arm box or cas ing 30. 'I'he push rod is enclosed by a tube 38°. 35 The fulcrum 21 and other movable parts of the valve mechanism are lubricated to reduce friction and wear thereof. During operation the push rod 28 is periodically reciprocated to cause opening and closing of the 40 valve. When the valve is opened or unseated, gases are discharged from the cylinder I8 into the exhaust conduit I9, in which as 'described above there may be a pressure higher than the sur rounding atmospheric pressure. Due to this dif 45 ference in pressure, the hot exhaust gases nor mally have a tendency to flow upward into thc small clearance existing between the valve stem 2| and the wall of the surrounding channel 22. This flow of hot gases forces out and burns away 50A all lubricant in the clearance space, causes over- ' heating of the valve stem, and ‘by creating a pres sure above atmosphere in the rocker arm box, expels the lubricant therefrom. This upward 55 2,112,045 2 The modiñcation of my invention shown in Fig. 4 comprises a valve casing 5|) having a channel effects is reduced or eliminated in accordance 5| for accommodating a valve stem 52. Two with my invention by the provision of auxiliaryT . spaced apart annular recesses 53 and 54 sur means which cause an artiñcial draft or blast rounding the valve stem 52 are formed in the along the valve stem 2|. Preferably I provide channel 5|. The recess 53 in this arrangement is means for causing a counter-flow of iluid such as connected by a conduit 55 to a space subject to air with respect to the flow of combustion gases. pressure equal to or less than that of the atmos In the present instance I have shown two spaced phere, for instance the intake chamber of a com apart recesses 3| and 32 formed in the channel 22 pressor. The recess 53 is disposed near the lower and surrounding the valve stem 2| near its lower end of the valve stem, that is, adjacent the valve 10 end. The recess 3| which is formed nearest the disk, whereas the recess 54 is disposed on the valve disk 24 is connected to a conduit 33 for con side of the recess 53 remote from the valve disk. ducting air (or other fluid) under pressure to the i The recess 54 communicates by a conduit 56 with recess. rI‘he other end of the conduit 33 is con the atmosphere. The provision of the recess 56 iiow of hot combustion gases with its injurious 15 nected to a source of air or other fluid having an vented to atmosphere is important whenever the stance it is shown connected to the air duct or 20 outlet conduit I4 (Fig. 1) of the ñrst supercharger other recess 53 is connected to a point of subat mospheric pressure because in this case the ex istence of low pressure in the recess 53 would cause the lubricant in the upper end of the valve stem and the rocker arm, not indicated, to flow absolute pressure higher than the (maximum, average) absolute pressure within the exhaust manifold or chamber I9. In this particular in stage, the connection being made ahead of the carbureter I6 whereby air from the first stage of the supercharger is forced through the conduit 33 into the recess 3| surrounding the valve stem 25 2|. The portion of the channel 22 in the valve casing intermediate the recess 3| and the lower end of the channel is made slightly wider to form a clearance 34 of a width suflìcient to permit a iicw of air at high velocity from the recess 3| 30 towards the disk or lower portion of the valve stem. This counterflow of air prevents or re downward along the valve stem. This downward flow of the lubricant is reduced byy the provision of means creating a pressure equal to the atmos 25 phere at a point above the recess 53, in the pres ent instance within the recess 54. During oper ation, exhaust gases are permitted to flow upward along the lower end of the valve stem 52 until they reach the recess 53, whence they are dis 30 charged through the conduit 55. Thus, whereas in the arrangement of Figs. l and 2 means are duces the flow of combustion gases in the opposite provided for creating an artificial flow in down that is, towards the valve stem, direction. Since the pressure established in the warddirection, in the arrangement of Fig. 4 means are provided 35 recess 3| is higher than that within the rocker for creating an artificial flow upward along the 35 arm box, this higher pressure might cause a iiow valve stem, and other means are provided for of air through the clearance space between the valve stem and the channel into the rocker arm reducing the iiow of air and lubricant from the box, thereby effecting ejecting of lubricant from upper part of the valve stem into the recess 53. this box. To prevent this I provide intermediate Furthermore, whereas in the arrangement of Fig. the >iirst recess 3| and the rocker armbox a second 2 the lower end portion 34 ofthe channel is some recess 32 which is vented to atmosphere through what wider to deñne an annular space with the valve stem, in the arrangement of Fig. 4 the lower a conduit 36. The channel portion 35 intermedi ate the two recess 3| and 32 has a good sliding or end of the channel 5| has a sliding fit with the packing iit with the valve stem. The cross sec tional area of the conduit 36 and the recess 32 ist. appreciably larger than that of the clearance be tween the valve stem and the channel so that any iiuid or gases passíngthrough the channel portion 35 will escape to atmosphere without creating in the recess 32 a pressure above atmosphere. The modification> of Fig. 3 comprises a valve casing 40 forming a channel 4| for a valve stem 42. A recess 43 corresponding to the recess 3| ~ci' Fig. 2 is formed in the channel 4| and con nected to a source 44 of high air or ñuid pressure. In accordance with my invention a lower por tion 45 of the channel 4| intermediate the recess valve stem, similar to the sliding ñt intermediate the two recesses 53 and 54 and corresponding to the sliding ñt intermediate the recesses 3| and 32 of Fig. 2. - Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment 5o, thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means. l What I claim as new and desire to secure by 55 Letters Patent in the United States is: A stumng box for an exhaust valve having a stem and a disk for controlling the ñow of exhaust gases from a source to an exhaust, means having and made wide enough to permit the iiow of ' spaced upper and lower annular recesses sur 60 compressed air from the recess 43 towards the rounding the end of said stem near the disk, lower portion of the stem 42. The arrangement means for maintaining in the lower recess a pres is such that the air is discharged from the recess sure greater than that existing in such exhaust, 43 at high velocity, the velocity being gradually and means for venting the upper recess to at converted into pressure as the air leaves the mosphere, the channel between the lower recess and the disk forming a clearance to permit air lower end of the- flared or Venturi-shaped chan 43 and the end of the channel 4| is Venturi-shaped nel portion 45, thereby preventing or reducing ' contained in the lower recess to iiow at high ve the ñow of combustion gases along the stem in locity along the stem towards the disk. the opposite direction. " SAMUEL R. PUFFER.