US2511823A - Klotsch - Google Patents

Description

June 13, 1950 P. KLOTSCH 2,511,823

INTERNAL-COMBUSTION ENGINE Filed April 15, 1946 4 Sheets-Sheet 1 f INVEN TOR. &9 We

wmzm fimwaw Patented June 13, 1950 INTERNAL-COMBUSTION ENGINE Paul Klotsch, Cincinnati, Ohio, assignor to Crosley Motors, Inc., Cincinnati, Ohio, a corporation of Ohio Application April 15, 1946, Serial No. 662,323

18 Claims. (Cl. 123-195) 1 This invention relates to an internal combustion engine and to a method of fabricating it. The invention is described particularly in relation to a four cylinder, four cycle, watercooled gasoline engine suitable for use in a light automobile, but is suitable for many other uses such as for propelling motor boats, for driving dynamos and the like. Also, the structure of the engine and the principles involved in its fabrication are readily susceptible to use in engines of greater size and horse-power and in air-cooled engines, and in compressor machines.

The principal objective of this invention has been to provide an engine in which the strength and rigidity characteristic of a. structure fabricated from castings or forglngs are combined with the light weight, high efficiency, and low cost of manufacture of an engine fabricated from sheet metal stampings and thin wall members, without the disadvantages usually attending either type of construction.

Two main concepts of fabrication or production have been utilized to obtain this result. In the first place, the engine as a whole comprises a cylinder block which is constructed of stamped or formed thin wall elements or members, and a cast, or die-cast light weight crankcase which furnishes the foundation for the engine block. These two primary structural members are made separately and independently of one another and are fastened together by bolts and nuts. Together these static parts withstand all of the forces generated in the operation of the engine. 1 Their functional cooperation in as-.

vention is based upon the concept of associating the stamped or formed thin wall elements which form the engine block assembly by frictional or press fits, and then uniting the various elements one with another into permanent assembly by brazing. This principle of fabrication is employed throughout the engine block even including the assembly of those parts which are subjected to the most severe strains, and temperature, such as the cylinders and heads, the manifolds and valve seats, and the bottoms of the cylinders, one to another. In this manner threading and tapping operations are eliminated, no gaskets whatsoever are needed or used, and thin wall smooth surface sections are presented at critical areas subjected to high heat and high stress to contribute their high cooling efllciency to best advantage;

In more detail, the engine block consists essentially of a simple fiat base plate having cylinder tubes press fitted and brazed to bores therein. Each cylinder barrel, constituted by a thin-walled tube of alloy steel, has a thin-walled pressed steel cap or head at its upper end, the critical joint between the two being constituted b a brazed press fit. The upper or head ends of the cylinder barrels are cross braced, one to another, through truss-like bridges constituting manifold members which are press-fitted and brazed to the cylinder caps and, on top of this manifolding, a valve box is utilized comprising sheet metal elements which also are fastened together by brazing. By virtue of the strength and rigidity of the union of the cylinders with the base plate at their lower ends, and the union of the cylinder heads to the manifolds at their upper ends, the valve box is relieved of the duty of furnishing additional strength and, therefore, is fabricated primarily with regard to cooling and to lubrication functions.

This assembly is contained within a sheet metal shell, the space between the shell and the cylinder tubes forming a water Jacket encasing the circumference of each cylinder barrel, the cylinder head, the manifolds and the valves contained within the manifold. From top to bottom of the block, the assembly is devoid of gaskets at pressure areas. This construction is of utmost importance in relation to the problem of corrosion, for, if exhaustgases are permitted,

through faulty gaskets, to escape into the water of the cooling system and water becomes acid and soon the metal becomes pitted and corroded. In a cast engine block having thick walls such corrosion is of no great importance but, where the metal parts are constructed of light gauge sheet steel it is apparent that the metal soon would be perforated by pitting of an otherwise minor nature, and the engine would be rendered useless. However, even uncontaminated water is corrosive to sheet steel more than to cast metal and it has been discovered that the corrosion from this source may be eliminated entirely by applying a thin continuous moisture and corrosion resistant film of resin over all of the interior water jacket surfaces by pumping resinous finishing material, in liquid form, through the water jacket, then draining the water jacket and baking the finish. The high heat transfer efficiency of the thin wall structural elements of the engine block permits this coating to remain unimpaired throughout engine life despite the high combustion temperatures which exist within the cylinders and within the manifolds at the opposite sides of the metal members to which the coating is applied.

Except for the cylinder barrels and valve seats. the engine block members are formed of sheet steel; the barrels and valve seats are made of high carbon alloy steel capable of being hardened by quenching in air. For erection of an engine block constructed in this manner, the various parts are dimensioned together in self-sustaining frictional or press-fit engagement, brazing material is applied at the joint areas in suitable manner, and the assembly is then passed through a brazing furnace or brazing oven which has the double function of heating all of the parts to brazing temperature and of heating the cylinder barrels "and valve seats to hardening temperature. Subsequently the assembly is air quenched to set the brazing material and, simultaneously, to lower the temperature of the cylinder barrels and valve seats below critical or hardening temperature. after which the assembly is allowed to cool slowly for relieving any strains that may have been set up in the brazing operation. This single operation therefore unites the parts and hardens those surfaces of the engine which are subjected to mechanical wear during operation.

The crankcase is a heat treated aluminum casting, except for heavy steel bolts which are set in it. These bolts are disposed in transverse webs, two bolts per web, the webs being located one on each side of each cylinder so that the base of each cylinder is nested among four heavy bolts. Each bolt protrudes above and below the web in .which it is set and held against axial displacement.

The protrusion of the base bolts above the webs is utilized for attaching the flat base plate of the cylinder block to the crankcase upon which it bears. The protrusion of the bolts below their supporting webs is utilized to secure the lower half of each crank shaft bearing to the upper crankcase and, therefore, to the engine block. Consequently each crank bearing is sustained from the engine block just as though it were an integral part thereof. The crankcase therefore has only the primary structural duty of furnishing pads upon which the motor may be mounted to a chassis or frame, aside from its function as a housing for lubricant. As a result. it is very light in weight.

While the salient features of the present engine and the mode of fabrication have been discussed in the foregoing portion of the specification, other improvements of a somewhat more detailed nature also are disclosed in the following detailed description of the drawings in which a typical embodiment of the apparatus is illustrated.

In the drawings:

Figure 1 is a longitudinal vertical sectional view taken centrally through the cylinder block and crankcase assembly.

Figure 2 is a top plan view of the assembled cylinder block and crankcase.

Figure 3 is a longitudinal sectional view taken on line 3-3, Figure 1, illustrating the arrangement of the several intake and exhaust conduits and valve ports with respect to the cylinder heads.

Figure 4 is a longitudinal sectional view taken on line 4-4, Figure 1. showing the cylinders, base plate, crankcase, and the arrangement of studs securing the base plate to the crankcase.

Figure 5 is a view of the assembly of Figure 4 as seen from the bottom or crankcase side thereof, showing the crankcase construction and its relationship to the cylinder block assembly.

Figure 6 is an enlarged longitudinal cross sectional view taken on line 6-6, Figure 1.

Figure '7 is a cross sectional view taken on line 1-1, Figure 6, illustrating the construction of one of the struts in the upper portion of the cylinder block assembly.

Figure 8 is a vertical sectional view taken on line 8-8, Figure 6, illustrating one of the fastening studs with respect to the cylinder block base plate, crankcase and lower bearing cap.

Figure 9 is a horizontal cross sectional view taken on line 9-9, Figure 6, showing one of the stiffening webs of the crankcase with the studs located therein.

Figure 10 is a sectional view similar to Figure 6, showing the crankcase and cylinder assembly with the crank shaft, the connecting rod and piston being shown in phantom lines to illustrate the application of the explosive forces to the crank shaft with respect to the static parts of the engine.

The assembly shown in the drawings, in general, comprises a sheet metal cylinder'block unit indicated at II, and a crankcase indicated at l2. The cylinder block, as an integral assembly, includes a base plate 13 to which the lower ends of the cylinders are brazed. This base plate is seated upon the crankcase l2 and is secured in place by studs H and the nuts l5 thereon. The studs, which are preferably of alloy steel for high tensile strength, pass through the crankcase and are anchored at their lower ends in the lower bearing caps of the crank shaft bearings by means of the nuts I8 screwthreaded thereon. The pressure of combustion generated in the cylinders to force the pistons downwardly is of considerable magnitude, tending to force the cylinder block upwardly and the crankshaft downwardly. Since the crank shaft is carried by the lower bearing caps and the bearing caps are tied directly to the cylinder block by the studs N in tension, the disruptive stresses are substantially absorbed by the studs with little or no direct stresses in tension exerted on the crankcase.

Engine block II, as shown in Figure 1, is, in effect, subdivided and consists essentially of an upper section, generally indicated at IT, providing support and housing means for the valve actuating mechanism, and a lower section, generally indicated at l8, including the base plate I3, cylinders, cylinder heads and valve bonnets or conduits.

The upper block section l1, in cross section, consists of a closed rectangular box-like casing with internal cross ribs and sleeves to resist the compression forces developed between the cam shaft and the lower ends of the valve springs. The compression pressure of the valve springs is imposed upon the bottom wall of the section II and the cam shaft is secured upon the top wall, thus setting up compression forces between the top and bottom walls tending to disrupt or force them apart. The structure is appropriately reinforced at the stressed areas to resist these forces substantially without deformation, and being an integral unit, absorbs the stresses and substantially isolates them from the lower section l8.

At the lower section of the block the cylinder barrels are received within bores in the base plate It, in press-fitted relationship thereto, whereby a joint is provided, after brazing. which is very strong, both laterally and longitudinally. It will be understood that the structure of the present invention is intended for use in the fabrication of multi-cylinder engines, the particular number of cylinders being optional. In the present disclosure a four-cylinder engine is illustrated but the identical construction is applicable to engines having a number of cylinders greater or less than four.

The upper ends of the cylinders include heads or closures 26 provided with valve ports, valve bonnets and spark plug bores. The upper portions of the cylinders, cylinder heads, and valve bonnets or conduits all are enclosed by a sheet metal water jacket 2| which is substantially rectangular in cross section; and the jacket includes a top wall upon which the upper section II is mounted. Water jacket 2| extends downwardly to cover the cylinder for the approximate area of piston travel and includes a lower wall through which the lower ends of the cylinders project to join the base plate It.

Described in detail with particular reference to Figure 1 of the drawings, showing the complete assembly, the cylinder block unit I l constituting a brazed assembly, is shown mounted upon the crankcase. The cylinders [9 of the cylinder block and the valve seats, are formed of seamless drawn steel or steel alloy tubing, having an appropriate wall thickness, for example, from 1*," to 3%", while the remainder of the elements are stamped from sheet steel.

The base plate I3 is formed from relatively heavy gauge steel, for instance, V steel plate, having its bottom surface machined to provide a sealed joint with the upper surface of the crankcase. The plate includes a series of apertures 22 into which are fitted the lower ends of the cylinders iii. For the purpose of providing a stop to regulate the position of the cylinders in the plate, the cylinders are counterturned to provide shoulders, as at 23. With the cylinders located within the plate, a copper brazing ring is applied to the lower portion at the juncture of the cylinder with the base plate I3. This wire completely encircles the cylinder and when the assembly is heated in the brazing furnace, the wire fuses and flows into the crevice between the aperture and the base of the cylinder, completely filling the crevice and securely uniting the cylinder to the base plate. Similar brazed joints uniting various other parts of the assembly all are indicated by the numeral 28 throughout this description. Brazing paste may be used in place of copper or brazing wire when more convenient to apply.

The upper ends of the cylinders are provided with closures or cylinder heads ill preferably formed of thin wall cold drawn steel stampings to facilitate rapid heat dissipation. 'The top of the cylinder heads are domed upwardly and the interior diameter of the flange of each cylinder head includes a counterbored portion 26 into which the upper end of the cylinder is is pressfitted. A brazing wire applied at this point encircling the cylinder, enables the brazing material to flow by capillarity into the crevice thereby providing a gas-tight seal and securely uniting the cylinder head to the cylinder.

The internal diameter of the cylinder at the upper portion may include a chamfer or outwardly tapered portion 21 merging generally with the inside wall of the cylinder head. The chamfered portion, starting at the lower line of juncture with the cylinder wail M including the cylinder head. forms the combustion chamber for the engine, the line of the chamfer coinciding approximately with the upp r limit of. the piston travel. This arrangement avoids an excessive wall thickness at the joint and permits rapid cooling, the combustion chamber being substantially surrounded by the water in the jacket.

A further advantage, in relation to engine periormance, is believed to be contributed by this detailed construction. Machining of the cylinder head by counterboring and machining oi the cyllnder barrel by counterturning to mating diameters providing a press fit, insures such continuity of contact between the two parts that, after brazing, an assembly is provided having the characteristics of an integral structure. This arrangement, therefore, enables attachment of the head to the cylinder through a bond which is suiilciently strong to sustain the high disruptive forces attending each explosion in the cylinder. On the other hand, this thinwall structure, coupled with the inward chamfer on the end of the cylinder barrel and the thin wall construction of the head, is believed tov provide sufilcient momentary yieldability or expansibility to prevent preignition of the fuel and knocking. While the exact force reactions occurring at the moment of explosion are not known, still it is believed that either the cylinder or head, or both. may expand outwardly enough to relieve the exceptionally high compression values which commonly are considered to attend the development of engine knock. At any rate, the engine does not knock, even under adverse load and adverse fuel conditions.

Each cylinder head 20 is provided with a pair of ports or openings 28-28 into which are fitted the valve bonnets, or conduits, 3B and ill respectively, the bonnets 30 being for intake bonnet and the bonnets 3| being for exhaust. Fabrication of the valve inserts and valve bonnets and the assembly and joining of these parts to the cylinder heads is the subject matter of the co-pending application of Herbert P. Junkin for Metallic structures and method of fabricating same, filed September 13, 1945, hearing Serial No. 616,004, now Patent No. 2,486,654, to which attention is invited. A brief description of this construction is as follows:

Ports 28-28 include bushings or valve seat inserts 32, each bushing including a head or an nular base 33 disposed at the inside of the cylinder, and a shank portion 84 extending upwardly above the top of the cylinder head. The head 33 seats against the inner side, serving as an abutment for the bushing. This head later is machined to form a valve seat.

The lower ends of. the valve bonnets are provided with an external peripheral head 35, the bead defining a rim designed to fit snugly within the ports 2B-2ii, and also serving as a stop or abutment, bearing against the top surface of the cylinder head. At the interior, the rim telescopically receives the shank portion 34 of the bushing, the shank being pressed snugly within the rim portion of the conduit. The shank is then deformed by radially expanding a circumferential portion of it outwardly into the area of the bead 35, by means of suitable dies. Shani;

AsshowninFigureslsnd3,theintakevalve bonnets II connect the cylinder heads in pairs and are in the form of U-shaped conduits having lateral nipples It at their upper central portions. The nipples 86 extend through the water jacket II. Conduits it are arranged to be connected to an intake manifold, which is not shown since it may be of conventional construction.

The lateral conduit SI of each intake bonnet II is secured at its inner end by brazing as indicated at 28 (Figure 3), the conduit being provided with an annular flange ll telescopically to receive the inner end of the conduit in press-fit connection. The conduit flares outwardly from this point and includes an annular inturned lip or flange 39 which lies against the inside surface oi the water jacket II as shown in Figures 3 and B.

A stiffener plate 40, formed of relatively heavy gauge sheet metal is brazed as at to the outside of the water jacket 2! and extends for the full length thereof. This plate reinforces the jacket to permit it to support the weight of the exhaust and intake manifolds and faciliates attachment of the manifold outlets.

The flanges 19 of the lateral conduits 3B are engaged respectively by short thimbles or collars 4| having annular outwardly turned flanges, 2-42 at the opposite ends thereof. These collars are formed from seamless light gauge tubes, the flanges being formed by deforming or upsetting the ends. Ferrules or rings 43 are disposed at the outside of the plate 40 and include grooves 44 to receive the exterior flanges 42 of the collars 4i. Thus, each collar 4! extends through its ring and through the openings in the water jacket and stifiener plate and the ends are upset to form the flanges 42-42, thus clinching the assembly securely together.

It will be apparent that the collars 4|, in effect, form a liner sealing off the joints between the water jacket and stiffener plate, thus eliminating several joints, and additionally strengthening the assembly. After assembly, the joints are brazed as indicated at 25 to provide a gas and fluid tight seal.

As shown, an exhaust valve bonnet If is provided individually for each cylinder. These bonnets or conduits are in the form oi right angle elbows, being respectively connected at opposite ends to the cylinder heads and outlet openings in the water jacket and stiffener plate to communicate with an exhaust manifold. These conduits are joined to the cylinder heads and to the stillener plate, as shown in Figure 6, in the same manner as the intake bonnets ll previously described.

From this detailed description, it will be seen that the upper ends of the cylinder barrels are joined together by the U -shaped rigid intake bonnets which are interconnected with the heads thereof. This holds the upper ends oi the cylinders against longitudinal displacement with respect to one another. However, the upper ends of the cylinders also are connected by the right angle exhaust bonnets to the stiffener plate 4| and in view of the close spacing of the cylinders and bonnets the cylinders are thus prevented from lateral movement with respect to one an-,

other. This is of particular importance in view of the lateral thrusts to which the cylinders are subjected during successive power and compression strokes when the engine is in operation.

As previously indicated, the intake and exhaust manifolds may be of conventional construction and they are adapted to be fastened to the stiffener plate 40 by means of screws which engage a series of thlmbles 45 extending into the interior (5 of the water jacket. These thimbles are screw machine parts provided with shoulders 40 which abut the interior wall of the stiflener plate, the projecting portions of the thimbles being appropriately. crimped and brazed in position so that they do not turn when the manifold screws are tightened. The screw threaded bores in the thimbles are blind and the escape of water at these points thereby is prevented. To facilitate gas-tight connection of the manifolds to the engine the faces of the ferrules 4! are machined to present a finished plane surface which preferably does carry a gasket. It is to be noted, however. that this gasket is beyond the confines of the water chamber and any leak might impair operating efliciency but will not cause corrosion problems.

In the preferred structure, the valve bonnets II and il are formed of light gauge sheet metal stamplngs, for example, metal approximately thick. Since the bonnets are not exposed to the direct combustion pressure in the cylinders, serving only as passageways for the vapor and burned gases when the valves are open, they are formed of light gauge sheet metal which facilitates rapid dissipation of heat to the cooling water by which the bonnets are surrounded.

At the top of each of the bonnets Ill and 3!, an upwardly projecting sleeve 41 is formed integrally with the bonnet to contact the top wall of the water jacket at the underside thereof. The end of the sleeve includes a lateral flange 49 having facial engagement with the wall to strengthen the joint mechanically and to provide an increased sealing area with respect to the adjoining surfaces of the sleeve and water jacket wall. If desired, the flange 48 may be in the form of a flange formed integrally with the upper edge of the sleeve 41. The assembled joint is brazed, as at 25, to produce a strong and rigid water-tight joint between the wall and the top of the valve, bonnet sleeve. Both the intake and exhaust valve bonnets are provided with identical sleeves 41, and the joint in each instance is formed as above described.

For a four cylinder engine fabricated in accordance with the present invention, each cylinder head includes respective exhaust and intake ports 2B28. The exhaust ports are provided with individual bonnets 3| and the intake ports are connected in pairs to the respective intake bonnets 30 each bonnet thus serving two'cylinders. The valve inserts or bushings 32 are common to both sets of intake and exhaust ports and are identical in construction with the exception that the intake bushing is made slightly larger in diameter than the exhaust bushing for more efficient engine performance.

llevelled valve seats 5|! are provided on the inner edges of the inserts 30 by machining after the engine block has been assembled and brazed. Thus, in Figure l, the inserts are shown before machining, and in Figure 6, the inserts are shown after machining. These seats are engaged by poppet type valves 5| which are indicated by the broken lines on Figure 6. Both the valve inserts and cylinder bonnets, as previously indicated, preferably are made of a high carbon, air hardening alloy steel, such as Athenu." and the seats and walls may be finished by grinding or lapping to form smooth true surfaces.

The stems of the valves 5| project upwardly and slide within valve stem guides (not shown) which are pressed into guide bushings 52 inserted and brazed in place within the sleeves 41 of the respective valve bonnets It and II. The upper ends of the valves are provided with suitable springs, cam followers and guide mechanism (not shown) and are actuated by an overhead cam shaft 53 as shown in broken lines on Figure l.

The upper valve housing unit I'l essentially comprises a rectangular casing having a bottom wall 54 and side and end walls 55. It ls formed preferably of a light gauge sheet metal stamping, open at the top and subsequently closed by a cover plate 51 which is brazed in place after the interior parts of the casing have been assembled. For this purpose, the cover plate includes an upstanding marginal flange 58 which is adapted to fit within the side and end walls 55 of the casing to form a flanged joint, the surfaces being joined by brazing as indicated at 25. This arrangement further provides a trough or recess 59, approximately square in cross section, formed by depressing a marginal area adjacent the flange 58 and extending around the four sides of the cover plate. The recess 59 serves to retain a gasket (not shown) upon which is seated the lower edges of a top closure or cover 50, shown in broken lines on Figure 1.

Casing I! as shown in Figures 1 and 2, includes a plurality of cylindrical drawn sheet metal receptacles or cups 6| disposed interiorly thereof, the bottoms of which rest upon the bottom wall 54 while the upper ends abut the underside of the cover plate 57 to which the upper ends of the cups are brazed. Each of the cups (ii is further provided with a prefabricated cylindrical sleeve or liner 62, which includes a head or flange 53 at the top providing a shoulder seated upon the top cover plate 51. The sleeves are telescopically fitted within the cups BI and brazed thereto. These sleeves serve to house and guide the cam followers, the followers being of cylindrical form and making a sliding fit therein. The valve springs are under compression between the follower and the bottom of the cups 6!. These parts form no part of the present invention and therefore are not shown in the drawings.

The valve guide bushings 52 are disposed in axial alignment centrally within the cups 6!, extending downwardly through openings in the cups and through openings in the bottom of the casing and water jacket. The lower portion of each bushing fits telescopically within the sleeve 67 of the valve bonnets 30 and 3i, as previously described. Each valve bushing 52 includes a head 64 at its upper end providing a shoulder which is seated upon the bottomsurface of the cup M where it is brazed in place as at 25. In practice the valve inserts 32, guide bushings 52 and the cups and sleeves 6i and B2 are pressed into assembly as closely in axial alignment as is practicable. However, due to allowable tolerances and other variations incident to stampings of this nature and to production methods of manufacture and assembly, minor variations in the parts are likely to be present. In order to compensate for these variations, the valve inserts 32, guide bushings 52, and the cups and sleeves 5i and 52 are arranged to be machined in assembly and line reamed or ground and lapped to provide the necessary finish and clearance for efficient operation of the valve stems and associated parts.

In order to strengthen and rigldify the casing l1 and additionally to provide supports for the cam shaft bearings, a series of transverse struts or webs 66 i Figure 7) are disposed interiorly of the casing, each preferably being disposed immediately beneath a cam shaft bearing mounting pad 61 respectively. a number of these pads being provided to support the cam shaft appropriately. The webs comprise relatively light sheet metal stampings, and each web is made up of two symmetrical stampings, preferably brazed together, providing oppositely extending right angle flanges 68 (see Figures 6 and 7). Each web is further provided with a pair of vertical semi-circular corrugations 69'59 which form cylindrical sleeves Ill when the opposite halves of the webs are placed face to face. The upper ends of the sleeves ID are arranged telescopically to receiv' a threaded bushing II, which extends through an opening in the top cover plate 51 and bearing block 61. The lower shank portion of each bushing includes a peripheral flange I2 engaged by a bead 13 formed in the upper portion of its cooperating sleeve 1|). The threaded bushings H are arranged to receive the screws (not shown) for mounting the cam shaft bearings. This structure provides a rigid support for the bearings, there being provided one assembled web for each bearing respectively.

At the forward end of the casing I! a main cam shaft bearing pad 55 is located. The mounting for this hearing is reenforced by means of a pair of cylindrical sleeves preferably of light gauge sheet metal, brazed as at 25 to the upper and lower wall of the casing II.

In assembly the webs 56 and flanges 12 of the sleeves are positioned within the beads 13, the two halves being secured together with the threaded bushings being disposed within the sleeves. The assembled webs are placed within the casing H, the cups BI and valve guide bushlngs likewise being in assembled relationship within the casing. After this, the cover plate 51 is placed in position and the bearing pads 61 located upon the top surface of the plate in engagement with the projecting upper ends of the threaded bushings H. The casing is now completely assembled in place upon the top of the water jacket and the various joints indicated at 25 are ready for brazing when the assembly is placed in the brazing furnace. The joint 25 between the water jacket and casing is formed preferably by a sheet of brazing material placed between the parts.

At the forward end of the engine, a vertical tube H is provided to communicate with an opening in the base plate l3 at its lower end. Th s tube passes through the lower and upper walls of the casing i1 and at its lower end includes a flatwasher I5 seated within a groove formed in the tube. The washer provides a shoulder which rests upon the upper surface of the base plate l3. This serves to position the tube properly with respect to the base plate and the tube is securely joined to the base plate by means of the brazed joint indicated at 25, providing a fluid tight seal at the base of the tube. The upper end of the tube is also joined to the casing by brazing, flanges 1516 formed in the upper and lower walls 51 and 54 of the casing being used for this purpose.

Tube 14 houses a vertical drive shaft shown in broken lines shown in Figure 1. This shaft includes bevel gears at its upper and lower end respectively which mesh with bevel gears keyed to the crank shaft and cam shaft. The drive from the crank shaft is transmitted to the cam shaft in this manner.

The rearward end of the cylinder block assembly is likewise provided with a vertical tube IT, communicating with the interior of the casing I1 at its upper end and extending through the base plate I! at its lower end to communicate with the crankcase. Tube I1 serves as an oil return conduit. The engine is provided in any suitable manner with an oil pump for maintaining a flow of oil from the crankcase to the cam shaft and the cam actuated mechanism which is associated therewith.

For lubrication, cups GI are provided with openings I8 which permit the excess of oil to drain from the interior of the receptacle. This oil ultimately flows back to the crankcase through the return conduit H. To permit the return of excess oil, the lower portions of the webs 66 are curved as shown in Figure 6 thus providing openings 19 permitting free passage of the oil.

The water jacket 2I, shown in the drawings, consists essentially of sheet metal stampings generally rectangular in cross section comprising a top wall SI and side and end walls 82, the side and end walls being overlapped and brazed at the corners as at 25 (Figure 3). The jacket extends downwardly of the cylinders approximately to the lower limit of piston travel and the bottom is formed by a panel 83 which is joined to the lower edges of the side and end walls 82 by means of the lapped, brazed seam 00. A series of openings defined by the vertical circular flanges 05 in the bottom panel encircle the cylinders I9. These joints are likewise secured by brazing 25.

Intake and outlet nipples G and 8'! respectively communicate with the interior of the water Jacket serving to supply water or other coolant to the engine, the intake nipple being located at a low point for increased cooling efficiency. These nipples are connected to the cooling system of the engine in the usual manner by suitable lengths of hose. Each nipple includes a bead 88 serving as an abutment or stop, the inner end of the nipple being crimped and clinched in place as at 80 after which the parts are brazed together. In order to aid in distibuting the coolant uniformly, the water jacket includes a, longitudinal outwardly expanded corrugation 90 preferably semi-circular in cross section communicating centrally of its length with the intake nipple 0B. The corrugation flares outwardly from its opposite ends, thus providing an enlarged passageway relative to the cylinders to facilitate the flow of coolant.

In respect to the distribution of water through the jacket, to insure uniformity of cooling, attention is invited to my co-pending patent application, Serial Number 666,455, filed May 1, 1946,

entitled Cooling system for internal combustion engines, now Patent No. 2,456,951, in which a baffle plate is disclosed containing metering apertures for regulating the amount of water delivered from the inlet to each cylinder area.

As shown in Figures 3 and 6, one side wall of the water Jacket is provided with a, series of recesses or depressions 9|, each accommodating a. spark plug 92. as shown in broken lines on Figure 6. The spark plug is in screw threaded engagement within a screw threaded bushing 93 secured in an opening in the cylinder head. The spark plugs preferably are disposed at an angle with respect to the side wall of the water jacket. Therefore, bushings 93 are mounted in an angular boss 94 formed in the top of the cylinder head 20. The bushings are secured to the respective cylinder heads by upsetting or crimping the inner ends thereof, thereby forming shoulders engaging the interior surface of the cylinder head. The recessed portions SI of the water jacket include flange portions 06 integral therewith encircling the exteriors of the bushings 93. Each bushing is further provided with an exterior flange 01 providing a shoulder with which the sheet metal flange of the water jacket is engaged. Thus, the flange 06 serves to space the interior surface of the water Jacket from the cylinder head. At the same time, the flange 96 and the head are in compressed encas ment with one another between the flanges 08 and of the spark plug bushing. After the parts are brazed together a. very strong Joint is provided between these thin walled metal pieces. The arrangement permits cooling water to flow freely around the entire spark plug bushing thereby providing an effective cooling system for the tip of the plug at which the heat is most pronounced. The assembled parts are thereafter joined by brazing 25 to provide a gas pressure-tight seal with respect to the cylinder head and bushing and a fluid-tight seal between the bushing and water jacket.

The crankcase generally indicated at I2 upon which the cylinder block assembly is mounted, comprises in cross-section a semi-circular die casting, preferably of aluminum alloy. Longitudinal and transverse ribs stiffen and rigidity the structure. The casting also includes a rectangular flanged opening 00 communicating with the lower open ends of the cylinders. The upper surface Hill of this flange is faced or machined to receive a, gasket IOI disposed between the flange and the base plate IS, the base plate likewise being preferably faced or machined, thereby effecting a fluid tight seal between the two surfaces.

The crankcase includes a series of transverse webs or ribs I02 disposed between the cylinders of the cylinder block. These webs are preferably four in number, one for each cylinder, and include semi-circular flanged bearing recesses I03 formed therein. These flanged recesses provide receptacles for suitable bearing liners indicated at I04, Figure 6. A lower bearing cap I05 is provided, one for each of the ribs, the caps being secured in place by the nuts It in screw threaded engagement in the studs I4.

Transverse webs I02 include thickened sections I06 which preferably are circular in cross section disposed in pairs straddling the bearing bosses I03. The portions I06 provide sumcient metal thickness to accommodate holes tapped and drilled therethrough to receive the studs ll. These studs further include integral hexagonal nuts I01 formed thereon which are disposed below the surface of the base plate I3 in cut-out portions I00 of the webs.

In assembly of the engine, the studs Il may be screw-threaded and tightened in place through the webs I02. The fabricated and machined cylinder block then is positioned upon the crankcase by projection of the studs through the aligned holes of the base plate I3, after which the nuts I5 are applied to the studs and are tightened. After assembly of the crank shaft. the nuts I B are threaded on the lower end of the studs to fasten the lower bearing caps III! in position. This arrangement permits the removal of the bearing caps without disturbing the cylinder block since the studs I4 are in screw threaded engagement in the crankcase and the nuts II hold the parts in assembly.

Although the studs are screw threaded in the webs I02, the forces in tension set up in engine operation are not transmitted to the block, but are transmitted through the studs to the bearing cap III! as previously described. The shanks of the studs are engaged in the webs for assembly purposes and convenience in removing the crank shalt and the bearings, or for repairs, without dismantling the cylinder block from the crankcase.

It will be noted in Figures 6 and 10 that the upper edge of the webs I2 which are located between adjacent cylinders, serves as a support for the base plate in this area. Thus, each cylinder is individually supported upon a rigid integral box-like structure formed by the transverse webs and the longitudinal sides of the crankcase.

The crankcase is provided with a pair of longitudinal ribs Ill one on each side thereof. These ribs strengthen the crankcase longitudinally inasmuch as the crankcase serves as a mounting base for the entire assembly and is subjected to longitudinal forces due to the engine weight and to shocks which may occur when the engine is installed in an automobile.

The engine is mounted preferably by means of mounting lugs H2, cast integrally with the crankcase and located at the forward end of the casting. As installed in an automobile the engine mounting and drive arrangement may follow that disclosed in the patent to Powell Cros -y, Jr., No. 2,253,479. This arrangement csseniially consists of a rigid connection between the rear wheels and the engine, universal joints being eliminated, by permitting the engine to pivot slightly. The thrust is transmitted throu h a rigid tube secured at its forward end to the engine and transmission assembly and at its rearward end to the differential housing, the propeller shaft being enclosed in this tube.

The crankcase is rigidly trussed by means of the transverse ribs "I! which reenforce it against torsional forces developed in the operation of the engine and against the thrust of the rear wheels by means of the longitudinal ribs Ill. Since the engine assembly is mounted upon the crankcase and the crankcase in turn is mounted upon the frame of a vehicle or other foundation, the resistance to the torque force of the crank shaft will react in an equal torque transmitted to the crankcase through the base plate l3. This force is resisted by the lugs H2 which are anchored securely and is thus absorbed by the crankcase.

The present design and organization of parts results in very substantial advantages with reference to engine performance and likewise with reference to fabrication and assembly of the parts. In connection with the latter, it will be noted that all of the parts fit snugly one within another and that steps or abutments are provided for all such parts to position them correctly with respect to each other upon being pressed home. The advantage of this arrangement is two-fold. First, it eliminates the need for jigs and fixtures to hold the parts properly located in assembly for brazing and thus effects a savings in time and expense. With the exception of the assembly of the cylinder barrels. cylinder heads and base plate which may be joined by a heavy pressure fit, the design of the remaining parts makes them capable of bein": pressed together by hand, preferably by the use of a simple arbor press. Those parts which are clinched together are assembled preferably by means of a hand operated tool designed for 14 this purpose. The parts automatically locate themselves correctly upon being pressed home, due to the stops or shoulders provided for this purpose. To expedite assembly, the various parts are preferably dimensioned to make a light press fit for hand assembly and the simplicity of design permits this work to be done by relatively unskilled operators. The parts fit together with sufllcient tightness to hold together by friction prior to being braced. Second, a strong mechanical bond between the parts is insured when they are brazed because the arrangement provides contacting surfaces, with only narrow crevices within which brazing material is free to flow by capillarity. This results in an exceptionally strong union between the parts and likewise produces pressure-tight seals.

In preparing the assembly for brazing, brazing material, either in wire or paste form, is applied at the various joints required to be brazed. Since most of the parts are of cylindrical form, a wire is simply wound about the part at the joint and upon reaching the fusing temperature in the furnace the material flows into the joint by the combined action of gravity and capillary attraction. In instances where the brazing wire is necessarily applied beneath the joint, it may be secured in place by the application of a copper paste. In such instances the material jflriwg upwardly by capillary attraction into the In order to expedite the mechanical assembly of the parts the lower and upper sections, l1 and i8 respectively, may be assembled separately, the assembled units being joined together at the time of firing in the brazing furnace. Whether or not the units are assembled independently, it is preferable that the entire cylinder block assembly be brazed simultaneously, thus achieving a relatively uniform braze throughout the assembly.

Although the valve bonnets are formed of relatively light gauge sheet metal stampings, a high degree of strength and rigidity is imparted to them as a result of their formation. This is particularly true with respect to the intake bonnets which form arches as viewed in Figure 1, the combined effect of the intake and exhaust bonnets providing a truss-like structure spanning the tops of the cylinder heads and the top of the water jacket and securing the tops oi the cylinders together. This also rigidifies and strengthens the water jacket which derives its primary support at the top and also provides a solid support for the upper valve casing I! mounted on the top of the Jacket.

Following the fabrication and brazing of the engine block assembly, it is preferable first to machine the bottom face of the base plate, by surface grinding or the like, in order that this face may be used as a reference plane from which dimensions may be established in later machining operations. If the cylinder heads are not spaced uniformly from the lower surface of the base plate, the pistons will travel to different levels within the cylinders and the gases within the cylinders will not be compressed uniformly, from cylinder to cylinder; this may cause uneven power delivery, and also cause vibration. In the present construction the individual cylinder tubes may be cut substantially to finish length from tube stock without regard to precise dimensions in the cut-off operation. However, the desired exact spacing of the cylinder heads from the base plate surface is obtained by providing shoulders through counterturning or counter- ,boring to limit the engagement of the cylinder tubes with the base plate, and the engagement of the cylinder heads with the cylinder tubes. These shoulders, as shown in the drawings, may readily be spaced apart from one another precisely and uniformly. in this manner the need for great care in assembling operations is eliminated inasmuch as it is convenient to bring the parts together until the shoulders are engaged.

The cylinders, valve seats, valve stem guides and upper valve guide sleeves are formed of machine steel. After being brazed. these parts are rigidly integrated in the assembly and their relationship with each other is fixed. The rigidity of the structure compares very favorably with a cast cylinder block of similar proportions. Therefore, these parts which require to be finished accurately as to diameter and which require proper aligmnent with each other, are machine finished in assembly, the valve guides and seats being line reamed and ground according to standard practices. The cylinders likewise are machine finished to close dimensional tolerances according to the standard commercial practice such as by grinding and lapping. The cylinder block therefore is accurately finished to provide the required running fits for the moving parts of the machine. An advantage over cast engine block construction lies in the fact that the cylinders and guides are formed from selected alloy steels best adapted to the particular usage and free of impurities and imperfections frequently encountered in castings, and present hardened wear resistant surfaces.

The thin-walled steel cylinder barrel, having its lower end pressure fitted into the base plate and its upper end closed by a thin wall stamped steel cylinder head, pressure fitted thereon, constitutes a primary structural element of the engine upon which is directly imposed the maximum combustion pressures developed in engine operation.

Attempts in the past to directly and permanently braze the heads to the cylinders and eliminate the use of gaskets have resulted in failures due to weakness in the joint, at time permitting the head to blow off under maximum cylinder pressures.

To remedy this situation, designers have resorted to the expedient of attaching the heads by spot-welding or screw threading them on the cylinders, then sealing the joint by brazing. This proved to be unsatisfactory because the seal tends to be interrupted circumferentially due to the spot welds, and in the instance of the threaded engagement, by the irregular brazing surface presented by the screw threads. Furthermore, the screw threaded construction results in a relatively heavy metal section where the screw threaded flange of the head overlies the top of the cylinder, thus impeding the flow of heat from the combustion chamber.

In the present instance the head and base plate are directly joined to the cylinder barrel either by a shrinkage fit or by a heavy press fit. If by shrinkage fit a temperature differential is employed either by lowering the temperature of the barrel to contract it, or by raising the temperature of the head and base plate to expand them. An appropriate differential between the dimensions of the mating parts develops a relatively high pressure between them upon assembly, binding the parts firmly together when permitted to reach normal temperatures.

Whenthepartsareioinedbyapressfita metal-to-metal interference is created. the shouldered opposite end portions of the barrel being approximately .001" larger than the mating inside diameters of the head and base plate openings. The parts are pressed together under high pressure to join the head and base plate firmly to the cylinder barrel.

After pressure fitting of the parts, the cylinder assembly is brazed by the application of a brazing wire about the barrel respectively at the juncture of the head and base plate. Although the'joints are pressure fitted, the brazing material, upon fusing, penetrates between the ad- Joining pressure gripped surfaces of the joint in the form of a minutely thin film. It has been observed upon examination that this film extends for the full length and circumference of the joints, permanently uniting the parts, sealing the Joints and integrating the structure. It will be apparent the use of gaskets between the cylinder head is eliminated.

As shown in broken lines on Figure 6, the upper limit of piston travel, which defines the combustion chamber. is in the area of the pressure fitted flange of the cylinder head, at the top of the cylinder. It will be apparent, therefore, that during operation, the flow of heat from the combustion chamber will tend to raise the temperature of the cylinder above that of the head flange, the cylinder being exposed to the burning gases in the combustion chamber while the flange of the head is exposed exteriorly to the coolant in the water jacket. This temperature differential therefore tends to expand the cylinder with respect to the head tending to increase the gripping pressure of the brazed joint.

After having been brazed, the interior surface of the cylinder barrel is machined truly circular and finished to receive the piston and provide a seal with the piston rings. The wall thickness of the cylinder barrel, after machining, is at least 3%" at all points but need not be in excess of The exterior surface of the upper portion of the cylinder barrel and cylinder head, in which the maximum combustion temperatures are developed, are directly exposed to the coolant in the water jacket. These parts, being of thin walled construction, cause an exceedingly rapid dissipation of heat in this critical area, whereby the emclency and potential output of the engine is materially increased.

Having described my invention, I claim:

1. A cylinder block for an internal combustion engine comprising a series of seamless metal tubes, the axes of which are disposed parallel to one another and in the same plane, a metal plate adapted to be attached to a crankcase, said metal plate being apertured so that the lower end of each cylinder tube is disposed in an aperture in said plate, closures for the tops of said tubes, and intake and exhaust manifolds fabricated from sheet metal, said manifolds connecting and cross bracing each cylinder and a sheet metal member connecting said manifolds at their tops to form a truss-like structure which secures said tubular cylinders together at their upper ends.

2. In an internal combustion engine, the combination of a cylinder block and a, crankcase, the cylinder block comprising a plurality of hardenable alloy steel tubes constituting the cylinders. the tubes held together at their upper ends by sheet metal intake and exhaust manifolds, their lower ends held together by a thin sheet metal plate having apertures into which the respective ends of the cylinders are press-fitted and brazed, the crankcase consisting of an aluminum casting having transverse webs extending from side to side: one web on each side of each cylinder with bearings disposed in the webs and a series of bolts, two passing from the lower halves of each crankshaft bearing through the webs and through the plate which holds the tubular cylinder in assembly at their lower ends, thus, connecting the cylinder block and crankcase and providing four bolts about the periphery of each cylinder, directly attaching the bearings on each side of the cylinder directly to it, to contain the explosive pressure of each cylinder individually as it fires.

3. In an internal combustion engine, a cylinder block unit providing cylinders, a rigid plate supporting the lower ends of the cylinders and having for this purpose apertures therein in which the lower ends of the cylinders are secured, said block unit further including gas intake and discharge conduits fixed to the tops of the cylinders, a water Jacket surrounding the cylinders and conduits and including a top wall, and a valve guide unit secured along and upon said wail, said valve guide unit being of rectangular casing form and including valve guide sleeves and cross ribs.

4. In an internal combustion engine, a cylinder block unit including cylinders, a web of metal thickness greater than that of the cylinder walls, including apertures in which the lower ends of the cylinders are engaged, a reeniorcing structure disposed along the top or the row of cylinders, said structure being rigid and incorporating valve guides and manifolds in cross-arched relationship with the respective cylinders, the upper structure constituting a structural beam stiffening the cylinder block and maintaining the cylinders against displacement.

5. A cylinder block and crank case assembly for an internal combustion engine comprising: a plurality of cylinder tubes, a base plate the lower end of each of said tubes respectively secured to the base plate, and the upper ends of the tubes respectively having individual cylinder heads secured thereon, a longitudinally trussed, box like unit disposed at the tops of the cylinder tubes, said unit providing a valve casing for housing the valve actuating mechanism, the cylinder heads being united to said valve casing by a plurality of valve bonnets extending between the cylinder heads and the valve easing; an independent, longitudinally trussed box-like unit disposed at the bottoms of the cylinders beneath said base plate and forming a crankcase including longitudinal reinforcing ribs formed on the top portion thereof and transverse reinforcing ribs, the base plate being mounted upon and secured to the crankcase.

6. A cylinder block and crankcase assembly for an internal combustion engine comprising: a, pair of upper and lower spaced parallel trussed units and a plurality of individual cylinder tubes disposed laterally therebetween, each of said cylinder tubes having an individual cylinder head secured upon its upper end a base plate common to the lower ends of the cylinder. tubes the upper of said trussed units providing a valve casing for housing valve actuating mechanism, said cylinder heads being united to said valve casing, the lower of said trussed units providing a crankcase for the engine and having longitudinal reinforcing ribs formed on the top portion thereof and transverse reinforcing ribs, the crankcase being 18 secured to said cylinder block base plate by means of bolts engaged in said transverse ribs.

'1. A cylinder block assembly comprising: a series of drawn cylinder tubes, a sheet metal base plate, said base plate being apertured and having the lower end of each cylinder tube pressed in respective aperture, thereof, a plurality of sheet metal closures for the tops of said tubes, said closures being pressed on the respective tubes and including respective intake and exhaust ports, and sheet metal intake and exhaust bonnets, said bonnets being pressed into said ports respectively, said cylinder tubes, base plate, closures, and bonnets being brazed together.

8. In an internal combustion engine, a plate in the form of a sheet like member having a plurality of bores in a line, a plurality of thinwalled seamless metal cylinder tubes having the respective endwise portions thereof press fitted int the bores of the plate and brazed thereto, the areas in brazed contact between the cylinders and the plate bores being of such extent that the brazing material is capable of resisting the shearing actions exerted thereon during engine operation.

9. A cylinder block construction comprising, a flat sheet oi metal of substantial thickness forming a base plate having a series of aligned apertures therein, seamless thin wall metal tubes, forming cylinders, having endwise portions thereof press-fitted and brazed in said apertures so as to project laterally from said base plate in substantial parallel relationship to one another, cylinder heads press-fitted and brazed to the opposite ends of said cylinder tubes, and sheet metal conduit members in the form of arches rigidly connecting the heads of adjacent cylinders one to another, whereby each cylinder supports each adjacent cylinder against independent movement.

10. A block for an internal combustion engine, comprising a plurality of thin wall, seamless metal tubes constituting cylinders, heads attached to the tops of said cylinders, intake conduits in the form of arches spanning adjacent cylinders and connected to the heads thereof, and exhaust conduits in the form of right angle elements disposed laterally with respect to said arches, one for each cylinder and extending from the head thereof, the said arched intake conduits having lateral nipples extending substantially parallel with said exhaust manifolds, the free ends of said exhaust manifolds and nipples being connected in common to a rigid plate, and a base plate which is common to the lower ends of said cylinder tubes and which is rigidly fastened thereto.

11. In an engine block for an internal combustion engine, at least a pair of cylinder tubes of seamless thin wall metal, a plate interconnecting the exterior peripheries of said tubes at one end thereof, said tubes having heads at the opposite ends thereof, an arch shaped conduit having its endwise portions respectively connected to said heads, and conduits in the form of elbows extending from said heads adjacent said arch conduit in directions lateral to said arch conduit.

12. In an engine block for internal combustion engines, at least a pair of cylinder tubes of seamless thin wall metal, a plate interconnecting the exterior peripheries of said tubes at one end thereof, said tubes having heads at the opposite ends thereof, an arch shaped conduit having its endwise portions respectively connected to said heads, and conduits in the form of elbows ex- 19 i tending from said heads adjacent said arch conduit in directions lateral to said arch conduit, said elbows and said arch conduit having projections respectively aligned with said cylinders forming valve guide seats.

13. An engine block for internal combustion engines, comprising at least a. pair of cylinder tubes of seamless thin wall metal, a plate interconnecting the exterior peripheries of said tubes at one end thereof, said tubes having heads at the opposite ends thereof, an arch shaped conduit having its endwise portions respectively connected to said heads, conduits in the form of elbows extending from said heads, adjacent said arch conduit, in directions lateral to said arch conduit, said elbows and said arch conduit having projections respectively aligned with said cylinders and forming valve guide seats, and a box above said cylinder heads adapted to contain valve actuating mechanism, said box having a bottom wall fastened to said projections.

14. A construction for an engine block fabricated from sheet metal, which comprises a plate of substantial thickness having an aperture therein, a cylinder having a counterturned portion defining a shoulder at one end thereof, the said counterturned portion being adapted to form a press fit with said aperture, and the said shoulder being spaced from the end of said cylinder a distance corresponding substantially to the thickness of said plate for engagement with the surface of said plate, and a cylinder head for the opposite end of said cylinder, the said cylinder end and head being configurated relative to one another to present a second shoulder spaced from the first shoulder a predetermined distance whereby the combustion space within the cylinder, by spacing of said shoulders, is fixed at a predetermined distance from the lower face of said plate.

15. A cylinder block for an internal combustion engine, comprising an assembly of thin wall metal elements, including seamless tubes, constituting cylinders, stamped sheet metal heads and a sheet metal base plate having apertures therein in spaced alignment for receiving endwise portions of the cylinder tubes in press-fitted relationship, the cylinder heads and the cylinder tubes having respective machined surfaces forming press fits one with another, arch-shaped conduits constituting intake passageways rigidly joining the heads of adjacent cylinders, and elbow-shaped conduits forming exhaust passageways extending laterally in respect to said arch-shaped intake conduits, said intake conduits having sidewise openings, a rigid manifold plate to which the free ends of said elbow-shaped conduits are connected, and means for connecting the sidewise openings in said arch conduits to said manifold intermediate the elbow-shaped conduits.

16. The combination, in an internal combustion engine. of a cylinder tube, a cylinder head having a spark plug aperture, a water jacket surrounding the cylinder tube, projecting above the cylinder head and having an inwardly flanged aperture aligned with said spark plug aperture in the head, and a thin wall bushing, threaded internally to receive a spark plug, said bushing being disposed withi Bald aligned apertures tiving lateral flanges at its jendwise portions. respectively engagingtbe interior surface of said head and the exterior surface of said water jacket, said water Jacket being spaced from said head by means of said inturned flange.

17. The combination of a cylinder head hav- 8 p rk plu aperture. a water jacket surrounding the head in spaced relationship thereto, said water'iacket having an aperture aligned with the aperture in said head, and a bushing disposed within said aligned apertures, said bushing being a thin wall member threaded internally to receive a spark plug and having latera1 flanges at its opposite ends respectively engaging the interior surface of said head and the exterior surface of said water jacket, said water jacket, bushing and head being brazed together in fluid and pressure-tight connection with one another.

18. In an internal combustion engine, a plate in the form of a sheet like member having a plurality of bores in a line, a plurality of thin-walled seamless metal cylinder tubes having the respective endwise portions thereof press fitted into the bores of the plate and brazed thereto, the areas in brazed contact between the cylinders and the plate bores being of such extent that the brazing material is capable of resisting the shearing actions exerted thereon during engine operation, the bottom face of the plate of smooth planar reference surface and the inner surfaces of the cylinders being true and at right angles thereto, and means including a truss-like upper structure for holding said cylinders to said plate as they are fired.

PAUL KLOTSCH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 853,288 Weidely May 14, 1907 1,113,124 Jacobs et al. Oct. 6, 1914 1,260,859 Bie Mar. 26, 1918 1,270,044 Murray June 18, 1918 1,286,667 Leipert Dec. 3, 1918 1,287,359 Leipert Dec. 10, 1918 1,299,709 Hall Apr. 8, 1919 1,467,251 Roos Sept. 4, 1923 1,529,812 Reineke Mar. 17, 1925 1,635,023 Angle July 5, 1925 1,639,648 Carrey Aug. 23, 1927 1,652,333 Vincent Dec. 13, 1927 1,775,852 Fisher Sept. 16, 1930 1,972,752 Balough Sept. 4, 1934 2,001,854 Shoemaker May 21, 1935 2,054,926 Caminez Sept. 22, 1936 2,064,461 Chilton Dec. 15, 1936 2,089,277 Loefiier Aug. 10, 1937 2,147,186 Alfaro Feb. 14, 1939 2,199,423 Taylor May 7, 1940 2,275,478 Taylor Mar. 10, 1942 2,287,399 Ware et al June 23, 1942 2,337,577 Taylor Dec. 28, 1943 2,444,963 Taylor July 13, 1948

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