US2787985A - Compression ignition internal combustion engine construction, including recessed pistons - Google Patents

Description

April 1957 M. c. KUEPFER ETAL 2,787,985

COMPRESSION IGNITION INTERNAL COMBUSTION ENGINE CONSTRUCTION, INCLUDING RECESSED PISTONS Filed April 22, 1954 5 Sheets-Sheet 1 1N VEN TORS Mwfilyew C.Kwepfer 'ErwuvAJ/IHonak 023130 H0 bskey ATTORNEYS Aprll 9, 1957 M. c. KUEPFER EI'AL 2,737,985

COMPRESSION IGNITION INTERNAL COMBUSTION ENGINE CONSTRUCTION, INCLUDING RECESSED PISTONS Filed April 22. 1954 3 Sheets-Sheet 2 IN VEN TORS Matthew aKwepfer ErwizoAJ Illorvwk a BY 0M0 Hoskey 03 9 %e4@&

ATTORNEYS April 9, 1957 M. c. KUEPFER ET AL 2,787,985

COMPRESSION IGNITION INTERNAL COMBUSTION ENGINE CONSTRUCTION, INCLUDING RECESSEID PISTONS Filed April 22, 1954 3 Sheets-Sheet 3 I I M zahe c g a/ w wgn er F ErwinAJ IHorv'a/k y 8 BY 0M0 Hal/sissy QwmQ ATTORNEYS United States Patent- COMPRESSION IGNITION INTERNAL COMBUS- TION ENGINE CONSTRUCTION, INCLUDING RECESSED PISTONS Matthew C. Kuepfer, Erwin A. V. Horiak, and Otto Holskey, Canton, Ohio, assignors to Hercules Motors Corporation, Canton, Ohio, a corporation of Ohio Application April 22, 1954, Serial No. 424,926

13 Claims. (Cl. 123-32) The invention or discovery relates in general to internal combustion engines of the compression ignition type and having preferably spherical injection, mixing, and combustion chambers of relatively small volume, one for, each cylinder of the engine, the minimum cylinder volume being relatively large, and each cylinder and the associated preferably spherical chamber being communicatingly connected with each other by a passageway.

The present invention or discovery relates more particularly to compression ignition engines of the foregoing general type and which include broadly the improvements set forth in the prior U. S. Letters Patent No. Re. 19,742, reissued October 22, 1935, to Otis D. Treiber, for his original U. S. Letters Patent No. 1,960,- 093, issued May 22, 1934. The present invention or discovery also relates more particularly to compression ignition engines of the type broadly set forth in said U. S. Letters Patent No. Re. 19,742, and to the type of such engines specifically set forth in the prior U. S. Letters Patent No. 2,062,951, issued December 1, 1936 to Otis D. Treiber.

In each of said U. S. patents, No. Re. 19,742, and No. 2,062,951, there is set forth a high speed, high compression, high power, compression ignition internal combustion engine in which the spherical chambers are located entirely at the sides of the cylinders, and in which the passageways open into the cylinders through the sides thereof, and in which the normally upper surfaces of the passageways are flat laterally continuous extensions of preferably fiat lower faces of the cylinder head and are tangential with the spherical inner surfaces of the spherical or constant volume chambers, and which engine is further characterized by a sideward and upward injection of the liquid hydrocarbon fuel into the spherical chambers, each fuel spray having an origin preferably at the crank shaft side of the associated passageway, and being directed sidewards and upwards towards the passageway and flat cylinder head inner face.

Engines including the improvements set forth in said U. S. Patents No. Re. 19,742 and No. 2,062,951 are characterized by operating at relatively high speeds which may be from 2000 to 3000 R. P. M., and at relatively high mean indicated pressures which may be as high as 160 pounds per square inch at 2000 R. P. M., and with a consequent relatively high power output, which is accomplished at an economical rate of fuel consumption.

In the engines set forth in U. S. Patent No. 2,062,951, the constant volume chambers are formed by parts adapted for relatively easy commercial production, and which form constant volume chambers having a maximum internal spherical surface area, and the parts of each constant volume chamber fitting with one another and forming the constant volume chamber end of the connecting passageway with a height less than the radius of the spherical inner surface.

The engines set forth in U. S. Patent No. 2,062,951 are furthermore constructed and arranged so as to substantially eliminate knock or detonation in the operation of the engine, without any substantial loss of power, by the provision of deflector means preferably a tongue or lip extending into the passageway opening from the lower face of the constant volume chamber end of the connecting passageway. The inner surface of the tongue or lip is a continuation of the spherical inner surface of the constant volume chamber, and the tongue or lip is adapted to intercept the conical fuel spray injected thereagainst toward the passageway.

Compression ignition internal combustion engines combining the improvements of said U. S. Patents No. Re. 19,742 and No. 2,062,951 have come into widespread use.

In certain instances in the operation of compression ignition internal combustion engines including improvements set forth in one or more of said U. S. Patents No. Re. 19,742 and No. 2,062,951, the diesel oil fuel used has been compounded with a sulphur compound, with the result that the piston or pistons of such a compression ignition internal combustion engine charged with such sulphur compounded fuel has or have had built up thereon an accumulation or deposit of carbonaceous matter which for any such carbonaceous matter deposited piston grooves the inner cylindrical surface of the cylinder or cylinder liner in which such carbonaceous matter deposited piston operates.

Such a carbonaceous matter deposited piston may be more broadly temed an oxidizable foreign matter deposited piston.

The accumulation or deposit of such oxidizable foreign matter on a piston in such an engine is believed to result from the incomplete combustion of fuel in such engine, such as the above described sulphur compounded fuel.

The objects of the present invention or discovery include broadly the provision of an improved compression ignition internal combustion engine capable of being operated by sulphur compounded fuel or other fuel ordinarily resulting in the accumulation or deposit of partially oxidized hydrocarbons on the piston or pistons of the engine, and in which parts of the engine are constructed and arranged with each other so as to minimize or completely prevent such accumulation or deposit of oxidize.- ble foreign matter on the piston or pistons of the engine. Such an improved compression ignition internal combus tion engine may be otherwise termed a clean piston operating compression ignition internal combustion engine.

The objects of the present invention or discovery more particularly include the provision of such a clean piston operating compression ignition internal combustion engine, and which may include improvements of one or more of said U. S. Patents No. Re. 19,742 and No. 2,062,951, and/or improvements of one or more of the applications for U. S. Letters Patent of Matthew C. Kuepfer, Serial No. 259,365, filed December 1, 1951, now Patent 2,735,412, issued February 21, 1956, and Serial No. 327,239, filed December 22, 1952, now Patent 2,690,742, issued October 5, 1954.

The foregoing and other objects are attained by the improved clean piston operating compression ignition inter nal combustion engine construction, apparatus, parts, combinations, and sub-combinations, which comprise the present invention or discovery, and the nature of which tion or discovery maybe described in general terms a8 including in an internal combustion engine-preferably combining the improvements-of said U. S. Patents No. Re.

19,742 and No. 2,062,951, 'and said Patents 2,735,412 and 2,690,742, and having in addition toother usual compression ignition internal combustion engine parts and/ or parts as set forth in said patents and applications, a construction and arrangement of each piston in which the piston includes a preferably circular top wall and a tubular side wall or skirt extending from the top wall towards the engine crankshaft, the tubular side wall or skirt including a larger section extending preferably for more than a half portion of the girth of the side wall or skirt, and a smaller section constituting a recessed section extending for the remaining portion of the girth of the side Wall or skirt, the recessedsection in the operation of the engine traversing the opening of the passageway into the cylinder bore or varying volume chamber in which the piston is operating, and said passageway extending between said cylinder and a side constant volume chamber into which the fuel is injected.

By way of example embodiments of the improved clean piston operating compression ignition internal combustion engine construction of the present invention or discovery ad parts thereof are illustrated in the accompanying drawings forming part hereof, in which Fig. 1 is a fragmentary transverse sectional view of a clean piston operating compression ignition internal combustion engine including one embodiment of the improved construction hereof, portions being broken away to illus trate details of construction and arrangement, and in which the piston is shown displaced from the cylinder head and from the passageway connecting the varying volume cylinder with the constant volume chamber, and in which the piston may be considered to be traveling towards the cylinder head on the compression stroke, and before commencing to traverse the end of the passageway terminating in the cylinder bore;

Fig. 2 is a fragmentary plan sectional view as on line 2-2, Fig. 1, looking in the direction of the arrows;

Fig. 3 is a detached top plan view of the improved piston shown in the engine of Figs. 1 and 2;

Fig. 4 isa side elevational view thereof, looking in the direction of the arrows 44, Fig. 3;

Fig. 5 is a fragmentary plan sectional view thereof, as on line 5-5, Fig. 4, looking in the direction of the arrows;

Fig. .6 is an enlarged fragmentary vertical sectional view thereof, as on line .6-6, Fig. 3, looking in the dircction of the arrows;

Fig. 7 is an enlarged fragmentary view similar to Fig. 1 and showing the piston in its maximum advanced posittion nearest the cylinder head on the compression stroke; an

Fig. 8 is a vertical sectional view thereof, as on line 8-3, looking in the direction ofthe arrows.

S1rnilar numerals refer to similar parts throughout the several views of the drawing.

The illustrated compression ignition internal combust1on engine is indicated generally at 10, and includes combined improvements of said U. S. Patents No. Re. 19,742. and No. 2,062,951, and said Patents 2,735,412 and 2,690,742, and the present improvements thereof.

The engine 10 is a six cylinder, four stroke cycle, single action, high speed, compression ignition internal combustion engine, in which the air for combustion is obtained normally directly from the atmosphere, and in which separate quantities of charges of the preferred liquid hydrocarbon fuel, such as diesel oil, are successively injected into the combustion chambers of the engine at successive timed intervals, one charge being injected into the combustion chambers of each cylinder during each four stroke cycle of the piston operatively mounted in the cylinder.

The engine 10, includes in combination with other parts of a high speed internal combustion engine, a unitary casting 1 1 including a lower crank case portion, not shown, and an upper cylinder block portion 12, and front and back cylinder heads 13 are secured at the upper end of the cylinder block portion 12, each cylinder head accommodating three cylinders, and one cylinder head 13 being shown in the drawings.

The cylinder block portion 12 includes therein walls forming the cylinders, one of which is shown in the drawings and is indicated at 14, and is preferably an integral part of the preferably cast iron cylinder block portion. As shown the cylinder block cylinder 14 is provided with a cylindrical liner 14-1.

Each cylinder liner 141 has a bore 20, and in each cylinder bore 20, a piston 21 is operatively mounted for reciprocation in the usual manner for high speed engmes.

Each cylinder head 13 includes a normally lower wall 28 which is provided for each cylinder covered thereby with 21 preferably flat normally lowersurface 29 extending transversely across the upper end of the bore 20 of the particular cylinder.

A usual gasket 30 as shown may be interposed in a usual manner between the normally lower wall 28 of each of the cylinder heads 13, and the normally upper wall 15 of the cylinder block portion 12.

As illustrated, the engine 10 is a valve-in-head engine, and accordingly each normally lower wall 28 of the cylinder heads 13 has formed therein above the normally upper end of the bore 20 of each cylinder-covered thereby, an air intake valve seat orifice 33 and an exhaust valve seat orifice 34, and each of the valve seat orifices has a valve seat formed therein.

A valve 35 is operatively associated with each valve seat orifice 33, and a valve 35 is operatively associated with each valve seat orifice 34, and each of the valves includes a valve head 36 fitting in its respective seat, and a valve stem 37 extending upwardly from the head.

The cylinder heads 13 have mounted therein valve stem guide tubes 38, one for each valve stem 37, and each valve head 36 is normally maintained in its seat by usual means such as a set of compression springs 39, one end of which reacts against a spring seat 40 formed about each valve stem guide tube 38 in the cylinder heads 13, and the other end of which reacts against a flanged washer, not shown, secured in a usual manner at the upper end of the particular valve stem 37.

Each air intake valve seat orifice 33 communicatingly connects with one end of an air intake port or passageway 53, the intake ports 53 being formed in the walls of the cylinder heads 13, and the intake ports of each cylinder head connecting at their outer ends with an intake manifold 54, and each intake manifold 54 communicatingly connecting as by means of an elbow, not shown, preferably with an air cleaner, not shown.

Each exhaust valve seat orifice 34- communicatingly connects with one end of an exhaust port or passageway 57, the exhaust ports 57 being formed in the walls of the cylinder heads 13 and the exhaust ports of each cylinder head terminating at their outer ends in a connector flange, not shown, whereby the exhaust ports may be communicatingly connected with an exhaust manifold, not shown.

In the engine 10, a chamber Cv is formed within the bore 20 of each cylinder liner i i-4i and between a normally top or end fiat circular face 62 of the piston 21 operating within the particular bore 2G and the opposite flat circular normally lower surface or face 29 of the normally lower cylinder head wall 28 covering the particular bore 20.

Each of the chambers Cv by reason of the reciprocation of the piston forming one wall of the samc may be termed a varying volume chamber, and in the engine 10, at top dead center, that is, when the end face 62 of each piston 21 has reached its position of maximum travel away from the crank shaft, there is only mechanical clearance between the end face 62 of the piston and the opposite fiat cylinder head inner face 29.

Walls of the engine form constant volume chambers, one for each cylinder. Each constant volume chamber Cc is located closely adjacent to and entirely at the side of the corresponding varying volume chamber Cv; and between each constant volume chamber Co and its cylinder, Walls of the engine form a passageway P communicatingly connecting at one end with the particular constant volume chamber Cu and at the other end with the cylinder bore of the adjacent varying volume chamber Cv.

Each constant volume chamber Cc is formed with a curved inner surface 70 which is partially symmetrical about an axis extending through the center 71 of the chamber Co and at right angles or normal to the plane passing through the center '71 of the constant volume chamber and the longitudinal axis 72 of the bore of the adjacent cylinder.

As illustrated, the curved inner face 70 of each constant volume chamber Co is preferably spherical.

Each passageway P connecting a particular constant volume chamber Cc with the adjacent varying volume chamber Cv is provided with an inner face 73 which is laterally and slopingly continuous with the preferably fiat inner cylinder head face 29 of the adjacent varying volume chamber Cv, and each laterally continuous passageway face 73 is tangential with the curved inner surface 70 of the constant volume chamber Cc connected with the adjacent varying volume chamber Cv by the particular passageway P.

The width w of each passageway P is preferably as illustrated somewhat greater than the diameter of the spherical inner surface 70 of each constant volume chamber Cc, and the minimum height h of each passageway P is preferably somewhat less than the radius of the spherical inner surface 70.

As illustrated, each constant volume chamber Co is formed by members located in a socket 74 formed in the upper end wall 15 of the cylinder block portion 12. The bottom surface 74-1 of each socket 74 is hemispherical. The upper surface 74-2 of each socket 74 is cylindrical and has a vertical axis passing through the center of the hemispherical surface 74-1, the radius of the cylinder surface 74-2 being the same as the radius of the hemispherical surface 74-1.

The members forming each constant volume chamber Cc and portions of its communicating passageway P as shown, include a bottom member 75 and a top member 76 which are separable from each other and which to gether fit in and mate with one of the sockets 74.

Each bottom member 75 includes a lower externally and internally hemispherical shell portion 75-1, an upper externally cylindrical portion 75-2 extending from the upper end of the hemispherical shell portion 75-1, and an upper flat end surface 75-5.

The external hemispherical surface of the lower shell portion 75-1 of each bottom member 75 mates with the internal hemispherical bottom surface 74-1 of its socket 74.

The top member 76 forming each constant volume chamber Co is externally cylindrical and its upper end extends upwardly beyond the top wall 15 of the cylinder block portion 12 and into a downwardly opening cylindrical recess 77 formed in the adjacent cylinder head lower wall 28. In the normally lower face of each top member 76, there is formed a cavity 78 which includes a curved inner surface portion 78-1 connecting with the spherical inner portions of the lower member 75.

Each cavity 78 also includes a fiat surface portion 79-1 extending tangentially from the curved inner surface portion 78-1, and opposite side surfaces 79-2 and 79-3 converging with the sides of the fiat tangential surface portion 79-1 and with the curved inner surface portion 78-1. The flat tangential surface portion 79-1 *curved surfaceportion 78-1, and forms-with the opposite side surfaces 79-2 and 79-3 and with a portion of the upper flat end surface '75-5 of the lower member 75 opposite the fiat tangential surface 79-1, the constant volume chamber end of the particular connecting passageway P.

The flat surface 79-1 of each top member 76 is thus the constant volume chamber end of the flat inner face 73 of the passageway P taken as a whole.

The remaining portions of each passageway P are formed by an extension of the inner face 29 of the adjacent and connected varying volume chamber Cv, by the side faces of a notch 81 formed in the top wall 15 of the cylinder block portion 12 betwen the constant volume chamber Cv and the adjacent socket 74, and by a cylinder end portion of the upper fiat end surface 75-5 of the lower member 75.

The air intake valve means heretofore described in general, comprise means operated in a usual manner for introducing preferably atmospheric air including gaseous oxygen, or in other words a combustion supporting medium, into each varying volume chamber Cv on the air intake stroke of the piston thereof; and the exhaust valve means heretofore described in general, provide means forexhausting each varying volume chamber Cv during the exhaust stroke of the piston thereof.

Means are also provided for injecting preferably liquid hydrocarbon fuel into each constant volume chamber Cc preferably during the compression stroke of the associated piston, and as illustrated the fuel injecting means includes for each constant volume chamber Co a pintle nozzle 82 each of which is operatively mounted in the cylinder block portion 12, and the discharge end 83 of each of which extends into and terminates in the constant volume chamber Cc, with which the particular nozzle is associated.

Each nozzle 82 is of usual construction, and is adapted to introduce into the constant volume chamber Co with which it is associated, an atomized conical spray of fuel particles, the conical spray having its origin 0 located between the plane of the inner face of the cylinder head and a plane of displacement of the piston from the inner face of the cylinder head, that is, at the crank shaft side of the passageway P; and the origin 0 of the spray is preferably located in the side of the internally spherical constant volume chamber Cc opposite the passageway P and the spray is preferably directed as illustrated sidewards and upwards towards the passageway P and towards the plane of the inner face 29 of the cylinder head, all as best shown in Fig. l.

The longitudinal axis 91 of each conical spray is preferably located in the plane, which is the plane of the drawing sheet of Fig. 1, passing through the center 71 of the associated preferably internally spherical constant volume chamber Co and the longitudinal axis 72 of the bore 20 of the associated cylinder.

For attaining the control of the flow of hot gases emerging from each constant volume chamber through its associated passageway, each bottom member 75 is provided with improved combined fuel spray and deflector means and gas flow directing means which as shown and preferably are constituted by a tongue or lip 76-7 which extends upwardly above the upper fiat end surface 75-5 of the bottom member 75 into the constant volume chamber opening of its associated passageway P, and the inner surface'of each lip 76-7 is a continuation of the spherical inner surface of the shell 75-1.

A passageway forming tongue 75-7 having parallel side faces 75-8 and 75-9 extends at opposite sides of a parallel plane indicated by the dot-dash line 91-1 in Fig. 2, and which passes through the center of the internal spherical surface of the bottom member 75. The outer end face 75-10 of the tongue 75-7 has a concave cylindrical curvature conforming to the curvature of the 7 cylinder bore. The tongue 75-7 fits in the notch 81 and thus properly positions the constant volume chamber forming bottom member 75. The top face of the tongue 75-7 is an extension of the upper fiat end face 75-5, of the bottom member 75.

Referring particularly to Fig. 2, the lip 76-7 extends upwardly from the inner end of the tongue 75-7 and symmetrically with respect to the plane 91-1. The upper end of the lip 76-7 has a convex curvature 76-8, and at one side of the lower base portion of the tongue 76-7 has a faired and concave curvature 76-9 merging at its upper end with the lower end of the convex curvature 76-8 and merging at its outer end with the spherical inner surface of the bottom member 75.

At the other side, the lower base. portion of the tongue 76-7 has a faired and convex curvature 76-10 merging at its upper end with the lowerend of the convex curvature 76-8 and merging at its outer end with the spherical inner surface of the bottom member 75.

Each of the concave curvatures 76-9 and 76-10 are also faired downwardly from a junction with the upper end face of the tongue 76-7 in a slope towards the bottom of the inner spherical surface of the bottom member 75.

As in said U. S. Patent No. 2,062,951, the area of each tongue or lip 76-7 is such as to intercept such part of the conical fuel spray injected into the particular constant volume chamber Cc as may reach the tongue or lip 76-7, and thus prevent the injection of any solid unmixed fuel through the passageway P into the varying volume chamber Cv.

The area of each tongue or lip 76-7 is preferably as illustrated relatively small as compared with the total area of the associated passageway P, the passageway opening above and about the sides of the lip or tongue.

As aforesaid mechanical clearance only is preferably provided between each fiat piston end face 62 and the opposite fiat inner cylinder head face 29 at the dead center position of the piston, and the total volume of each constant volume chamber Co and the associated passageway l, which constitute the clearance volume of the particular cylinder, is small relative to the maximum volume of the associated varying volume chamber Cv, so that the compression ratio of the engine may be high, for example 14 to l.

Parts of the engine it), not specifically described herein may be as set forth in said U. S. Patent No. 2,062,951, or may be other usual and similar engine parts.

The external surface of the constant volume chamber forming .vottom member '75 is provided with a cylindrical section 75-11 below the tongue 75-7 as best shown in Fig. 7. This cylindrical section 75-11 is formed as a recess partly in the upper externally cylindrical portion 75-2 and the lower hemispherical portion 75-1 of the constant volume chamber forming lower member 75, the radius of the cylindrical section 75-11 being less than the radius of the externally cylindrical portion 75-2 of the member 75.

In the engine construction 10, the section of the wall of the constant volume chamber forming lower member including the cylindrical section is thinner than the other wall portions of the constant volume chamber forming lower member, and this thinner wall section is below the passageway forming tongue of the constant volume chamber forming lower member.

The cylindrical section 75-11 is spaced from the cylindrical upper surface 74-2 of the mounting socket for the lower member 75.

In the operation of the engine including the present improvements, the suction stroke of each piston draws intake air into the varying volume chamber Cv thereof, and the succeeding compression stroke of the piston compresses the charge of air and forces it with very rapidly increasing pressure and velocity from the varying volume chamber Cv through the associated passageway P and into the associated constant volume chamber Cc. As the piston moves across and substantially traverses the passageway P on its compression stroke, the opening of the passageway P into the varying volume chamber Cv is rapidly reduced in area, which still further increases the pressure and velocity of the air being forced through the passage way I into the associated constant volume chamber Co.

The fact that as aforesaid the passageway face 73 is an extension of the inner flat face 29 of the varying volume chamber Cl. and is tangential to the symmetrical and preferably spherical inner surface of the constant volume chamber Cc, causes an unusually effective whirling of the air forced into the chamber Cc, the velocity of the whirl increasing as the piston moves across the pasay P and approaches top dead center. i no fuel is sprayed in the manner above set forth across and towards the whirling or revolving air in the combuslion chamber Co, and the resulting combustion is of the desired character, whereby the engine operates at relatively high speeds and with relatively high mean indicated pressure.

It is to be noted that when the conical fuel spray 90 for any particular constant volume chamber Cc strikes the limited area of the associated lip 76-7 in the as sociated passageway P, towards which the spray is directed from the side of the constant volume chamber and at an angle to the tangential face of the passageway, there will be a deflection of a portion of the fuel spray above and about the sides of the lip 76-7 so that a portion of the fuel spray is impinged directly by the incoming air charge in and at the constant volume chamber end of the passageway P.

This combined effect is such that the mixing of the fuel charge with the incoming air charge commences virtually at the constant volume chamber end of the passageway and continues through the entire motion of the air charge in and through the constant volume chamber.

There is a very short period of time during which the complete cycle of mixing and combustion must take place, and the initiation of the mixing action of each unit volume of air charge as it enters its spherical side chamber, and the consequent attainment of a mixing action through a maximum period or portion of the complete cycle of mixing and combustion is of great benefit.

The operation of the improved engine 10 as thus far described is substantially the same as the operation of the engine set forth in said U. S. Patent No. 2,062,951. An engine including only the construction of said U. S. Patent No. 2,062,951, has the disadvantages previously set forth, and which may be summarized as including: (1) insuflicient heat transfer from each cylinder wall and constant volume or mixing and combustion chamber Cc to the cooling water; (2) expansion or bulging of portions of the separate walls of each mixing and combustion chamber such as to distort adjacent portions of the associated cylinder wall; and (3) unsatisfactory flow of hot gases emerging from each mixing and combustion chamber Cc.

These disadvantages are overcome by improvements set forth in said Patents 2,735,412 and 2,690,742, and which are incorporated in the present improved engine 10, as follows:

In the present improved engine 19, as above set forth, each mixing and combustion chamber Cc is constructed by a unit including a bottom member 75 and a top member 76 which are separable from each other and which together fit in and mate with one of the sockets 7 4. The relatively thin lower hemispherical shell 75-1 of the bottom member 75 is topped by the upper externally cylindrical portion 75-2 having thicker walls, and by the externally cylindrical top member 76 having thicker walls, and these differential wall thicknesses provide heat collecting and transfer means for each mixing and combustion chamber Ce, whereby transmission of heat from the chamber Cc through the cylinder blocl-c walls of the socket 74 to the cooling water is promoted, and transmission of heat is resisted from the chamber Cc to the cylinder wall of the associated cylinder and other parts of the cylinder block not in direct contact with members 75 and 76.

Also, as above set forth, the thinner externally cylindrical section 75-11, of the constant volume chamber forming bottom members 75 is spaced from opposite sections of the internal cylindrical upper surface 74-2 and upper portions of the lower internal hemispherical bottom surface 74-1 of its mounting socket 74 in the cylinder block.

This spacing of the thinner externally cylindrical section 75-11 from opposite sections of its mounting socket 74, forms an expansion chamber between the bottom member 75, and the cylinder block in which it is mounted. Such exapnsion chamber as shown and preferably is located below the passageway forming tongue 75-7 of the bottom member 75. Thus, expansion or bulging of the bottom member 75 by temperature rise during operating of the engine of which it is a part, is localized in its thinner externally cylindrical section 75-11, and such expansion takes place in the expansion chamber, Without pushing of the expanding section against the opposite section of the associated cylinder wall. Consequently there is substantially no distortion of the associated cylinder wall.

Accordingly in the improved engine 10, cylinders having a maximum bore may be included in an otherwise standard cast cylinder block, without encountering cracking of the cylinders or cylinder liner portions in the operation of the engine.

From the standpoint of the flow of hot gases from each chamber Cc through its associated passagaway P and into its associated chamer Cv, the provision of the lower faired concave curvatures 76-9 and 76-10 at each side of the upper central convex curvature of the lip 76-7, directs the hot gases upwardly as they emerge from the chamber Cc, so as to strike the lower face 29 of the cylinder head 13 and not the end face 62 of the piston, thereby avoiding damage of the piston and face and cylinder walls. Moreover the faired or rounded surfaces 76-8, 76-9, and 76-10, merging with each other and with the spherical inner surface of the chamber Cc, minimizes the tendency to burn-off of such bounding surfaces when sharp corners are present therein.

The convex curvatures 76-9 and 76-10 may be otherwise termed upwardly sloping channels at each side of the base of the deflector lip 76-7.

In the engine 10, each mixing and combustion chamber forming top member 76 is prevented from turning in the upper end of its socket 74, by the provision of a vertical groove 74-4 in the upper cylindrical surface 74-2 of the socket 74. A pin 76-11 extends from a side opening socket in each member 76 into the associated groove 74-4.

When desired each top member 76 may be welded to its associated bottom member 75.

The mixing and combustion chamber forming members 75 and 76 are preferably each made of heat resisting steel, which in itself serves to protect the cast iron cylinder block from damage by the hot gases in the mixing and combustion chambers.

In the foregoing description, certain surfaces and curvatures of the improved mixing and combustion chambers have been defined as being faired, by which it is meant that these faired faces'and curvatures have smooth junctions with adjacent surfaces without sudden or angular deviations.

A compression ignition internal combustion engine including only the improvements thus far set forth, is very satisfactory in operation when charged with usual diesel oil.

However, as above stated, when the diesel oil fuel or other fuel .used is compounded with a sulphur compound,

the pistons have had built up thereon an accumulation or deposit of partially oxidized hydrocarbons or carbonaceous matter which grooves the inner cylindrical surfaces of the cylinders or cylinderliners in which such carbonaceous matter deposited pistons operate.

Such a carbonaceous matter deposited piston may be more broadly termed an oxidizable foreign matter deposited piston.

In addition to the above described details of construction, the present improved engine 10, includes novel details of construction, whereby the improved engine 10 may be defined as a clean piston operating compression ignition internal combustion engine.

These additional novel details of construction are incorporated in each improved piston 21, and provide a novel coacting relationship between each improved piston 21 and its immediately associated parts forming the varying volume chamber Cv, the constant volume chamber Co, and the connecting passageway P, and between all of these parts and other parts of the engine.

Referring first to Figs. 3 to 6 inclusive, each improved piston 21 has an end face 62, as previously stated, which is the outer face of a generally circular piston top wall 21-1 from which there extends a tubular side Wall or skirt 21-2 having formed thereon and therein, a top land 21-3, upper taper ring grooves 21-4, and lower square ring grooves 21-5, there being a land between each two adjacent ring grooves.

For the purposes of the present improvements, the top land 21-3 includes a larger arcuate section 21-6 extending for more than a semi-perimeter portion of the top land 21-3, and a smaller section 21-7 extending for the remaining perimeter portion of the top land 21-3.

The smaller top land section 21-7 of the piston 21 has formed therein a stepped recess 21-8 including a lower arcuate recess portion 21-9, and an upper arcuate recess portion 21-10. The lower arcuate recess portion 21-? of the stepped recess 21-8 is deeper than the upper recess portion 21-10, and may be otherwise termed a piston top land pocket, and is formed entirely in the top land 21-3, the periphery of the piston pocket 21-9 being entirely displaced from the piston end face 62.

On the other hand, the upper recess portion 21-10 of the stepped recess 21-8 cuts across portions of the top corner 21-11 of the pocket 21-9 and portions of the top corner 21-12 of the piston 21, which is the junction of the piston top wall 21-1 and side wall 21-2, thereby producing a recessed circular formation for the top corner 21-12 of the piston 21.

The upper recess portion 21-10 of the top land 21-3 of the piston 21, may be otherwise termed a piston top land passageway, and extends between and across the piston end face 62 and the piston top land pocket 21-9.

The arcuate length of the upper arcuate recess portion 21-10 of the stepped recess 21-8 is preferably, as shown (Fig. 8), not greater than the width w of the engine passageway P; and the arcuate length of the lower arcuate recess portion 21-9 of the stepped recess 21-3 is preferably, as shown, greater than the arcuate length of the upper arcuate recess portion 21-10.

Referring now to Figs. 1,2, 7 and 8, in Fig. 1, as above stated, the piston 21 may be considered to be traveling towards the cylinder headv on the compression stroke,

and before commencing to traverse the end of the passageway P terminating in the cylinder bore 20.

As the piston approaches the cylinder head 13, the air in the varying volume chamber Cv is forced with increasing velocity and pressure into the constant volume chamber Cc into which a charge of fuel is being introduced, and the combustion of the fuel commences before the piston 21 reaches its position of top dead center nearest the cylinder head, as shown in Figs. 7 and 8.

At the position of the piston on the compression stroke at top dead center as shown in Figs. 7 and 8, the piston,

1 1 top land passageway 21-.-1 is located opposite the cylinder liner end of the passageway P and provides an up and down passageway communicating between the passageway P and the piston top land pocket 2i-9.

The gaseous mixture thus introduced into the piston top land pocket 21-9, if the charged fuel is a sulphur compounded diesel oil fuel, is believed to burn in the pocket 21-9, and as the piston moves away fromthe cylinder head 13 on the power stroke, the pressure in the varying volume chamber Cv becomes less than the pressure in the pocket 219, whereby a thin arcuate jet of burning fuel goes upwardly through the passageway 21-10, with the result that no carbonaceous deposit or accumulation is permitted to build up on the piston 21 as is the case if the pocket 219 and the passageway 21-10 are not present. The piston 21. is thus a clean operating piston, even though the fuel used is compounded with sulphur.

In the foregoing description, certain terms have been used for brevity, clearness, and understanding but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved constructions illustrated and described herein are by way of example, and the scope of the present invention or discovery is not limited to the exact details of construction set forth.

Having now described the invention or discovery, the construction, the operation, and use of preferred embodiments thereof, and the advantageous new and useful results obtained thereby; the new and useful constructions, and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

We claim:

1. In an internal combustion engine, a cylinder having a bore extending therethrough, a cylinder head having an inner face extending across one end of the cylinder bore, a piston operative for reciprocation in the cylinder bore and forming with the cylinder bore and the cylinder head inner face a cylinder chamber, walls forming a mixing and combustion chamber entirely at one side of and spaced from the cylinder chamber and a passageway extending between the cylinder chamber and the mixing and combustion chamber and providing a communication between the cylinder head end of the cylinder chamber and the mixing and combustion chamber, means for introducing a charge of combustion supporting medium into the cylinder chamber, and means for injecting fuel particles into the mixing and combustion chamber, and the piston including a top wall and a side wall making junction with each. other at a top corner and the side wall of the piston having an annular recess formed therein provided with cylindrical recess surface means of smaller diameter than the piston diameter and the recess including a portion extending up to the piston top corner.

2. In an internal combustion engine, a cylinder having a bore extending therethrough, a cylinder head having an inner face extending across one end of the cylinder bore, a piston operative for reciprocation in the cylinder bore and forming with the cylinder bore and the cylinder head inner face a cylinder chamber, walls forming a mixing and combustion chamber entirely at one side of and spaced from the cylinder chamber and a passageway extending between the cylinder chamber and the mixing and combustion chamber and providing a communication between the cylinder head end of the cylinder chamber and the mixing and combustion chamber, means for introducing a charge of combustion supporting medium into the cylinder chamber, and means for injecting fuel particles into the mixing and combustion chamber, and the piston including a top wall and a side wall making junction with each other at atop corner and the side.

wall of the piston having a stepped recess formed therein,

the stepped recessincludinga first arcuate recess portion entirelydisplacedfrom the piston top wall and a second arcuate recess portion, the second arcuate recess portion constituting a portion extending into the piston topcorner, and the piston reciprocating between a top dead center position and a bottom dead center position, and the recess being aligned with the passageway at the top dead center position of the piston.

3. In an internal combustion engine as set forth in claim 2, and in which the second arcuate recess portion has a depth less than the depth of the first arcuate recess portion.

4. In an internal combustion engine as set forth in claim 3, and in which the passageway has a cylinder chamber end opening, and the cylinder chamber end cpening of the passageway has a width substantially equal to the arcuate length ofthe second arcuate recess portion.

5. In an internal combustion engine as set forth in claim 2, and in which the, passageway has a cylinder chamber end opening, and the cylinder chamber end opening of the passageway has a width substantially equal to the arcuate length of the second arcuate recess portion.

6. In an internal combustion engine, a cylinder having a bore extending therethrough, a cylinder head having an inner face extending across one end of the cylinder bore, a piston operative for reciprocation in the cylinder bore and forming with the cylinder bore and the cylinder head inner face a cylinder chamber, walls forming a mixing and combustion chamber entirely at one side of and spaced from the cylinder chamber and a passageway extending between the cylinder chamber and the mixing and combustion chamber and providing a communication between the cylinder head end of the cylinder chamber and the mixing and combustion chamber, means for introducing a charge of combustion supporting medium into the cylinder chamber, and means for injecting fuel particles into the mixing and combustion chamber, and the piston including a top wall and a side wall making junction with each other at a top corner and the side wall of the piston having a recess formed therein, the recess including a portion extending into the piston top corner, the piston reciprocating between a top dead center position and a bottom dead center position, and the recess being aligned with the passageway at the top dead center position of the piston, the recess in the piston being a stepped recess including a first arcuate recess portion entirely displaced from the piston top wall and a second arcuate recess portion constituting the portion extending into the piston top corner, the second arcuate recess portion having a depth less than the depth of the first arcuate recess portion, and the arcuate length of the second arcuate recess portion being less than the arcuate length of the first arcuate recess portion.

7. In an internal combustion engine as set forth in claim 6, and in which the passageway has a cylinder chamber end opening, and in which the arcuate length of the second arcuate recess portion is not greater than the width of the cylinder chamber end of the passageway.

8. A piston adapted for reciprocation in a cylinder bore of an internal combustion engine cylinder, the piston including a top wall and a side wall making junction with each other at a top corner and the side wall of the piston having an annular recess formed therein provided with cylindrical recess surface means of smaller diameter than the piston diameter, and the recess including a portion extending up to the piston top corner.

9. A piston adapted for reciprocation in a cylinder bore of an internal combustion engine cylinder, the piston including a top wall and a side wall making junction with each other at a top corner and the side wall of the piston having a stepped recess formed therein, the recess in: cluding a first arcuate recess portion entirely displaced from the piston top wall and a second arcuate recess portion, and the second arcuaterecess portion constituting a portion extending into the piston top corner.

10. A piston as set forth in claim 9, and in which the avera es 13 second arcuate recess portion has a depth less than the depth of the first arcuate recess portion.

11. A piston as set forth in claim 10, and in which the arcuate length of the second arcuate recess portion is less than the arcuate length of the first arcuate recess portion.

12. In an internal combustion engine, a cylinder having a bore extending therethrough, cylinder head means having an inner face extending across one end of the cylinder bore, a piston operative for reciprocation in the cylinder bore and forming with the cylinder bore and. the cylinder head means inner face a cylinder chamber, walls forming a mixing and combustion chamber entirely at one side of and spaced from the cylinder chamber and a passageway extending between the cylinder chamber and the mixing and combustion chamber and providing a communication between the cylinder head end of the cylinder chamber and the mixing and combustion chamber, means for introducing a charge of combustion supporting medium into the cylinder chamber, a deflector lip located in the mixing and combustion chamber end of the passageway, the deflector lip extending into the passageway and having sides and the passageway opening around the sides of the deflector lip, and means for injecting fuel particles into the mixing and combustion chamber and against the deflector lip, and the piston including a top wall and a side wallmaking junction with each other at a top corner and the side wall of the piston having a recess formed therein, the recess including a portion extending into the piston top corner.

13. In an internal combustion engine, a cylinder having a bore extending therethrough, cylinder head means having an inner face extending across one end of the cylinder bore, a piston operative for reciprocation in the cylinder bore and forming with the cylinder bore and the cylinder head means inner face a cylinder chamber, Walls forming a mixing and combustion chamber entirely at one side of and spaced from the cylinder chamber and a passageway extending between the cylinder chamber and the mixing and combustion chamber and providing a communication between the cylinder head end of the cylinder chamber and the mixing and combustion chamber, means tor introducing a charge of combustion supporting medium into the cylinder chamber, a deflector lip located in the mixing and combustion chamber end of the passageway, the deflector lip extending into the passageway and having sides and the passageway opening around the sides of the deflector lip, and means for injecting fuel particles into the mixing and combustion chamber and against the deflector lip, and the piston including a top wall and a side wall making junction with each other at a top corner and the side wall of the piston having a recess formed therein, the recess including a portion extending into the piston top corner, the piston reciprocating between a top dead center position and a bottom dead center position, and the recess being aligned with the passageway at the top dead center position of the piston.

References Cited in the file of this patent UNITED STATES PATENTS

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