US2374250A - Engine - Google Patents

Description

April 1945' A. E. WALDEN 2,374,250

- ENGINE Q Filed Nov. 23, 1942 3 Sheets-Sheet l INVEN TOR Hz/r662 z, 14/4218 April 1945- A. E. WALDEN 2,374,250

ENGINE Filed Nov. 23, 1942 3 Sheets-Sheet 3 INVENTOR ATTORNEKE Patented Apr. 24-, 1945 ENGINE Alfred E. Walden, Detroit, Mich., asaignor to Briggs Manufacturing Company, Detroit, Micln, a corporation of Michigan Application November 23, 1942, Serial No. 466,555

17 Claims.

This invention relates to internal combustion engines and especially to engines of the type in which the combustion chamber of each cylinder is principally or preferably to a large extent located within a rotatable valve in the cylinder head and driven from the engine crank or drive shaft in properly timed relation to the engine cyc e.

An object of the present invention is to provide anengine of the foregoing type having improved means for mounting the rotatable valve within the cylinder head thereby reducing power losses by reducing friction, eliminating hot spots, and reducing leakage of gases consequent to operation of the engine.

A further object of the invention is to provide an internal combustion engine having a rotatable valve of the generally'frusto-conical type provided with a portion of the combustion chamber and in which the wider end of the valve nular recess or channel to receive 9. correspond-- ingly shaped portion of the bottom of the valve, the construction preferably being such as to permit more adequate cooling of the valve adjacent portions thereof subject to high bearing pressures, also reducing friction between the partswhile rendering more devious the passage be-' tween the surfaces of the valve and mask plate tending to permit escape of gases and consequentloss of power. l

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming apart of this specification wherein like reference characters designate corresponding parts in the several views.

Fig. 1 is a fragmentary sectional elevation illustrating a portion of a multi-cylinder engine is positioned adjacent to and masked from the cylinder by a'plate having a central orifice leading into the combustion chamber, the plate being annularly recessed toreceive the end of the valve and the relation between these parts being such as to minimize gas leakage, overheating 0f the valve and frictional losses.

Still a further object of the invention is to 7 provide an improved engine in which the frustoconical valve has its inner end adjacent the cylinder largely confined within an annular recess in the mask plate and in such manner as to free the side wall of the valve along its bottom or inner edge, as well as freeing the bottom corner of the valve, from undesirable frictional engagement with the mask plate, the improved construction also permitting more eflicient cooling of portions of the side walls of the valve near the bottom thereof which are subject to high bearing pressures.

Another object of the invention is to provide an improved internal combustion engine of the type having a generally frusto-conical valve containing a portion, and preferably most, of the combustion chamber, the bottom of the valve including the bottom outer corner of the valve being confined for rotation within a recessed portion of a mask plate interposed between the outer end of the cylinder and the valve.

A further object is to provide a structure as last above mentioned in which the bottom outer corner of the valve is freed from excessive frictional engagement with themask plate.

Still a further object of the invention is to embodying the present invention.

Fig. 2 is an enlarged fragmentary sectional elevation illustrating particularly the associated cylinder head and rotary valve structure shown in Fig. 1.

Fig. 3 is a transverse section taken substantially through lines 3-3 of Fig. 1 looking in the direction of the arrows. I

Fig. 4 is an enlarged fragmentary sectional elevation illustrating a somewhat modified construction. I

Fig. 5 is a view similar to Fig. 4 illustrating a further modification.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be'understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

In the drawings there are illustrated, by way of example, several embodiments of the invention as applied to an internal combustion engine of the spark ignition type designed particularly for the power plant of an aircraft. The invention may obviously be embodied in engines for other purposes, such as automotive, marine and industrial engines. For most uses the engine is of the multi-cylinder type, although any number of cylinder units may be employed in any given engine. In the present embodiment, for the purpose of simplicity, a single cylinder unit of the engine is illustrated, it being understood that the remaining cylinders of the engine are identical to the structure herein shown and described.

Referring to Fig. l, the present engine comprises a suitable crankcase 20 within which is mounted a crankshaft 2! supported in bearings according to conventional practice. A cylinder 22 is secured rigidly'to the crankcase and has its lower or inner end projecting thereinto. Mounted to reciprocate within the cylinder is a piston 23 adapted to be connected in the usual manner by a connecting rod 24! to the crankshaft 2 I.

In the present engine the combustion chamber of the cylinded is formed principally within a rdtor or rotary member 25, this member comprising a frusto-conical body arranged immediately above the piston when at the top of its stroke and also having a cylindrical stem 26 projecting from the outer end of the rotor body. The rotor 25 fits within a correspondingly shaped substantially frusto-conical cavity 27 in an upper cylinder head member 28. The cylinder head of the engine may be said to comprise two portions or members secured together and to the upper end of the cylinder 22. In addition to the outer member 28 the cylinder head comprises an intermediate member 28 which may herein be termed the rotor mask or shield and forming the pressure control member for the rotor and head and also the throat. opening from the cylinder into the combustion chamher.

The upper or outer end of the cylinder is formed with external threads which are engaged by internal threads on the cylindrical skirt portion of the head member 29 as indicated at 3|. The member 29 in turn is provided with external threads which are engaged by internal threads on the cylindrical skirt portion of the outer cylinder head member 28, as indicated at 30. From this construction it will be seen that the cylinder head or mask member 28 may be screwed down tightlyover the outer end of the cylinder 22 until the annular shoulder 29a of the member 29 substan-.

tially abuts against or engages the upper or outer edge of the cylinder, as shown in Figs. 1 and 2'. Also it will be seen that the outer cylinder head ,member 28 is screwed down tightly over the mem ber 29 until the bottom shoulder 28a.- of the head 28 substantially engages or abuts against the upper flat ledge or face of the mask member or fire plate 29.

The horizontal mask or shield plate 29 terminates centrally in a projecting annular flange 32 which forms the throat opening 83 int the combustion chamber 34 of the rotor member or rotary valve 25. The bottom or inner end of the valve 25 is provided with an annular right angled recess 25a to receive the throat flange 32 of the mask plate, there being a predetermined clearance 29b between the adjacent vertical faces-of the portions 250 and 32 and also a similar clearance between the top face of the throat flange 32 and the adjacent portion of the valve 25, see

a rounded edge, and a predetermined clearance is provided between this valve portion and the wall 29d of the recess in the mask plate. The amount of the clearances between the bottom of the valve 25 and the adjacent portions of the mask plate at 2912, 29c and 2511 will vary in accordance with varying conditions. In the present instance these clearances over and above what is customarily required for 9, running fit may be from five to ten thousandths oi an inch.

The present engine is illustrated as being air cooled and, accordingly, the cylinder 22 is provided with projecting fins 35. Cooling fins 36 and 3'! are also provided on the cylinder head members 28 and 29, respectively. It will be understood that the present engine is not limited to an air cooled engine as it will be apparent that any effective cooling system may be utilized.

The rotor 25 is driven through the medium of the stem 26 which is positively connected to a driving gear in such manner as to permit slight relative axial and radial movement between the driving gear and the rotor. The stem 26 of the rotor is provided with external longitudinal splines 38 and is also provided with internal threads within the cylindrical bore thereof. The rotor is driven by a gear 39 having suitable gear teeth ill, this gear being formed with a depending cylindrical hub or sleeve li having a clearance over the stem 25. The gear ii aLso has internal tooth-like splines 52. A coupling member 43 fits within the annular space formed between the teeth d2 of the driving gear. 39, this coupling member having exterior teeth or splines dd fitting into the spaces between the splines 62 of the driving gear and also having internal splines l5 fitting within the spaces formed by the splines 38 of the stem 25. The coupling member 43 has an annular tapered surface engageable with a correspondingly shaped tapered surface 39a of the gear 39. at is a clamping nut having external threads engageable with the threads of the valve stem 2B and having an outwardly projecting hex Fig. 2. The valve 25 has an angular extension formed flange d'i. Interposedbetween this flange and the end of the stem 26 is a spring washer 48 having a central aperture through which the clamping nut projects, the washer being of a suflicient diameter to engage the upper face of the gear 88, as shown in Fig. 2.

The rotor body 25 is cored entirely around the combustion chamber 34 to provide a cavity 48 which is closed at the upper end of the valve by means of a screw plug 50 screwed tightly into the threaded portion of the valve stem 26 below the clamping nut 46. Any suitable heat transfer or conducting medium, such as metallic sodium. is introduced into the cavity 49 through the hollow stem 26, and sealed therein by the screw plug ll.

Referring to Fig. 1, the gear 39, which is attached to the projecting stem of the rotor 25, is driven through the medium of a gear 5! attached to a top horizontal shaft 52. This shaft is of the desired length to permit simultaneous driving of the rotors of a plurality of cylinders arranged in line. Attached to the end of the shaft 82 is a gear 53 which is driven by a gear 54 secured to the upper end of a tower shaft 55. This shaft is suitably housed at 51 and has secured t the lower end thereof a gear 58 which is driven through the medium of I. gear 88 attached to the crankshaft 2 I.

The rotor or valve 28 has a single port II in its side communicating with the combustion chamber 34 and adapted to register in succession with an intake port 80, a. spark plug at locg tion 60, and an exhaust port 8|. In this embodiment, therefore, the valve or rotor 28 is driven at one-half engine or crankshaft speed. As illustrated in Fig. 3, the upright side edges of the port. 59 of the vlave 25 are relieved or ground oiT at 59a. The amount of this relief will vary depending upon the metal employed in the construction of the valve and cylinder head. The relief may be several thousandths of an inch and its purpose is to permit expansion of the metal of the valve at points 59a without excessive binding against the wall of the cavity 21. During operation the edges of the valve opening 59 at 59a will expand suillciently to bring these edges out into running engagement with the cavity 21 to provide a seal at the opposite edges of the valve port 59. This construction with the edges of the port relieved at 59a. reduces wear at these points and, consequently, eliminates considerable friction.

Interposed between the upper end of the tapered wall of the valve or rotor 25 and the correspondingly tapered wall of the cylinder head cavity 27 is a rotatable thrust bearing ring 6| formed of a suitable material such a bronze or lead bronze alloy. The rotor is formed with an annularly extending recess to receive the frustoconical ring 6! which is a free floating bearing between the rotor and cylinder head. In like manner, there is interposed between the lower end of the tapered wall of the valve or rotor 25 and the tapered wall of the cylinder head cavity 21 a second rotatable thrust bearing ring 62 constructed similarly to the ring 8! and formed of the same metal alloy. This lower ring 62 is also housed within a similarly shaped annularly extending recess in the outer surface of the valve or rotor 25. It will be noted that the recesses in the rotor are somewhat wider than the bearing rings 55 and 62 so as to permit slight relative axial movement of the valve and rings during operation. The rotor 25 is relieved in the area 63 between the rings 6i and 52 thereby providing a clearance throughout the entire area between the bearing rings, which is normally somewhat greater thanthe clearance ordinarily provided for a running fit. This clearance at 53 in the present instance is about one to one and one-half thousandths of an inch and is preferably substantially equal to the combined running clearance at opposite faces of each of the bearing rings ti and $2. In other words, the clearance at 63 is preferably twice the clearance at one face of each of the bearing rings 68 and 62. Hence, it will be seen that the surface 53 will be sealed as a result of the explosion pressure on the valve 25, thus avoiding any leakage of gas through the exhaust port 8| during the power stroke.

In the embodiment of Fig. 4, wherein the compression ratio is somewhat less than in the previous embodiment, the depth of the mask plate 54 is increased so as to provide a throat opening 65 of considerably greater depth than the throat opening 33. The valve 66, with the exception of its lower end, is constructed substantially the same as the valve 25, having a cavity 51 entirely surrounding the combustion chamber 34 and containing a suitable cooling medium such as metallic sodium. The lower orinner end of the valve 66 has an extension 56a extending within a correspondingly shaped annular recess in the mask plate 64. In this instance the side walls of the extension 66a are substantially parallel and the angle between each or these side walls an inch as in the previous embodiment. It will be seen that the entire inner end of the valve 66 below the bearing ring 62 is-housed within the annular recess in the mask plate Bl. This corresponds to the construction in the embodiments of Figs. 1 and 2 in which the entire inner or lower end of the valve below the bearing 62 is housed within the recess in the mask plate.

In the embodiment of Fig. 5 the compression ratio of the engine is also less than in connection with the embodiment of Fig. 2, the depth of the mask plate being increased thereby providing a deeper throat opening 69. The valve in this embodiment is illustrated at It and is substantially the same in costruction as the valve with the exception of the shape of the lower end of the valve 70 which is housed within a recess in the mask plate 68. As illustrated in Fig. 5, the valve 10 has an extension 10a lying within a correspondingly shapedannular recess in the mask plate 68. In this instance the walls 68a and 68b of the mask plate recess extend substantially at a right angle to each other whereas the wall 680 of the recess is inclined upwardly and outwardly. The opposed faces of the valve extension 10a and the walls of the recess in the mask plate are spaced to provide a predetermined clearance which may be from five to ten thousandths of an inch as in the previous embodiments. Also, it

In the operation of the present engine the.

principal bearing loads during the explosion period are taken at the localities of the bearing rings SI and 52. Consequently, it is important that suflicient cooling of these localities be provided. Furthermore, there is a considerable tendency of the valve to expand outwardly at its lower or inner end where the valve becomes quite hot. In each of the embodiments it will be seen that the cooling cavity extends well below the lower bearing ring 62. Thus, the cavity d9 in Fig. 2 extends at tile below the ring 62 andopposite to the corner 25c. In Fig. 4 the cavity 67 extends at 67c below the bearing ring 62 and opposite the wall Me. In Fig. 5 the cavity H extends at Ha below the bearing ring 62 and opposite the wall 680.

Thus, in accordance with the present invention it is possible to reduce the temperature or better control the temperature of the bearing rings 62 since the entire area of the valve at the locality of this lower bearing ring is cooled by the cooling' medium within the cavity 49, 81 or H, the cooling medium being very close to these areas. Furthermore, by providing the clearances between the lower end of the valve and the adjacent walls of the recess in the mask plate and by extending the cooling cavity well down into this annular recess in the mask plate it is possible to reduce the temperature or better control the temperature of the lower or inner end 01' the valve. In particular there is less tendency of the corner 25c of the valve 25 or the lower outer corners of the valve extensions 86a and Illa in the embodiments of Figs. 4 and 5 expanding outwardly to an excessive amount which would otherwise cause binding of the valve, frictional losses and excessive wear.

I claim:

1. In an internal combustion engine having a cylinder with a reciprocable piston therein, a cylinder head provided with a generally frustoconical cavity-a rotatable valve having a combustion chamber and a bearing on the .wall of said cavity, and a mask plate interposed between the valve and piston and having a port communicating with said chamber, said valve having a portion extending within a recess in said mask plate beyond said bearing, there being a clearance between said portion and recess to permit expansion of said portion during operation of the engine.

2. In an internal combustion engine having a cylinder with a reciprocable piston therein, a cylinder head provided with ,a generally frustoconical cavity, a rotatable valve having a combustion chamber and a bearing on the wall of said cavity, and a mask plate interposed between the valve and piston and having a port communicating with said chamber, said valve having a portion enclosed at three sides within a recess in said mask plate.

3. In an internal combustion engine having a cylinder with a reciprocable piston therein, a cylinder head provided with a generally frusto-' conical cavity, a rotatable valve having a combustion chamber and a bearing on' the wall of said cavity, and a cylinder head portion interposed between the valve and piston and having a port communicating with said chamber, said valve having a portion beyond said bearing con fined at three sides in a recess intthe outer face of said cylinder head portion.

4. In an internal combustion engine having a cylinder with a reciprocable piston therein, a

cylinder head provided-with a generally frustoconical cavity, a rotatable valve having a combustion chamber and a bearing on the wall of said cavity, and a cylinder head portion interposed between the valve and piston and having a port communicating with said chamber, said valve having the outer portion thereof at its inner conical cavity, a rotatable valve having a combustion chamber and a bearing on the wall of said cavity, and a cylinder head member interposed between the valve and piston and having a port communicating with said chamber, said valve having the outer portion thereof at its inner end confined within a recess in said memher, the clearance between said outer portion and member being greater than the clearance between the bearing and the wall of the cavity to permit relative expansion of said outer portion and bearing,

6. In an internal combustion engine having a cylinder with a. reciprocable piston therein, a cylinder head provided with a generally frustoconical cavity, a rotatable valve having a combustion chamber and a bearing on the wall of said cavity, and a cylinder head portion interposed between the valve and piston and havin a port communicating with said chamber, said aavaasc valve having a portion extending within a recess in said cylinder head portion beyond said bearing and also having a cooling chamber extendin into said recess.

7. In an internal combustion engine having a cylinder with a reciprocable piston therein, a cylinder head provided with a generally frustoconical cavity, a rotatable valve having a combustion chamber and a bearing on the wall of said cavity, and a mask plate interposed between the valve and piston and having a port communicating with said chamber, said valve having the outer portion thereof at its inner end confined within a recess in said mask plate and also having a cooling chamber extending into said recess.

8. In an internal combustion engine having a cylinder and a cylinder head, a rotatable valve operable within a bearing cavity in said head and having a combustion chamber, and a cylinder hand portion interposed between the outer end of the cylinder and the bottom of the valve and having a port providing communication between the cylinder and said chamber, said valve having the outer portion thereof at its inner end confined within a recess in said cylinder head portion.

9. In an internal combustion engine having a cylinder and a cylinder head, a rotatable valve operable within a bearing cavity in said head and having a, combustion chamber, and a cylinder head portion interposed between the outer end of the cylinder and the bottom of the valve and having a port providing communication between the cylinder and said chamber, said valve having the outer portion thereof at its inner end confined within a recess in said cylinder head portion and also having a cooling chamber extending into said recess.

- 10. In an internal combustion engine having a cylinder and a. cylinder head, a rotatable valve operable within a bearing cavity in said head and having a combustion chamber, and a mask plate interposed between the outer end of the cylinder and the bottom of the valve and having a port providing communication between the cylinder and said chamber, said valve having the outer portion thereof at its inner end confined within a recess in said mask plate beyond said cavity. the bottom wall of said cavity tapering away from said port.

11. In an internal combustion engine having a cylinder and a cylinder head, a rotatable valve operable within a bearing cavity in said head and having a combustion chamber. and a mask plate interposed between the outer end of the cylinder and the bottom of the valve and having a port providing communication between the cylinder and said chamber, said valve having the outer portion thereof at its inner end confined at three sides within a recess in said mask plate.

. 12. In an internal combustion engine having a cylinder and a cylinder head. a rotatable ,valve operable within a bearing cavity in said head and having a combustion chamber, and a mask plate interposed between the outer end of the cylinder and the bottom of thevalve and having a port providing communication between the cylinder and said chamber, said valve having the outer portion thereof at its inner end confined at three sides within a recess in said mask plate, the outer of said sides tapering inwardly in the direction of said port.

13. In an internal combustion engine having a cylinder and a cylinder head. a rotatable valve ae vaaeo interposed between the outer end of the cylinder and the bottom of the valve and having a mrt providing communication between the cylinder and said chamber, said valve and cylinder head cavity having cooperating tapered bearing surfaces and the valve being extended inwardly beyond said surfaces for cooperation with the mesh plate.

it. In an internal combustion engine having a cylinder and a cylinder head, a rotatable valve operable within a bearing cavity in said head and having a combustion chamber, and a mask plate interposed between the outer end of the cylinder and the bottom of the valve and having a port providing communication between the cylinder 1 and said chamber, said valve and cylinder head tended inwardly beyond the bearing portion of i said cavity into juxtaposition to surfaces of the 80 I mask plate.

16. In an internal combustion engine having a cylinder and a cylinder head, a rotatable valve operable within a bearing cavity in said head and having a combustion chamber, and a member interposed between the outer end of the cylinder and the bottom of the valve and havin a port providing communication between the cylinder and said chamber, said valve being extended inwardly beyond the bearing portion of said cavity I to provide upright side wall portions into juxtaposition to surfaces of said member, there being greater clearance for expansion of the valve bevtween said surfaces and side wall portion than between bearing portions of the valve and said cavity.

17. In an intemalcombustion engine having a cylinder and a cylinder vhead, a. rotatable valve operable'within a bearing cavity insaid head and having a combustion chamber, and amask plate interposed between the outer end oi the cylinder and the bottom of the valve and having a port providing communication between the cylinder and said chamber, said valve and cylinder head cavity having cooperating tapered bearing surfaces and the valve being extended inwardly beyond said surfaces for cooperation with the mask platerand said valve having a cooling chamberextending inwardly beyond said surfaces.

ALFRED E. WALDEN.

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