US2148505A

US2148505A - Engine

Info

Publication number: US2148505A
Application number: US723056A
Authority: US
Inventors: Carl G A Rosen
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1934-04-30
Filing date: 1934-04-30
Publication date: 1939-02-28
Anticipated expiration: 1956-02-28

Description

Feb. 28, 1939. c. G. A. ROSEN 2,148,505

` ENGINE I Filed April 30, 1954 2 Sheets-Sheet l EIE.'.E EEEJQ- l/ lll/lll INVENTOR. (arl 61H. Rosen ATTORN Feb- 28, 1939.

cl G. A. ROSEN i 2,148,505

ENGINE Filed April 30, 1934 2 Sheets-Sheet 2 INVENTOR. 6dr/ R059 ATTORNEY.

Patented Feb. 28, 1939 ENGINE Carl G. A. Rosen, Oakland, Calif., assigner to Caterpillar Tractor Co., San Leandro, Calif., a corporation of California Application April 30, 1934, Serial No. 723,056

11 'Claimm 'I'he present invention relates to compression ignition and the like engines, and more particularly to the provision of improved fuel combustion and injection means for such engines.

It is an object of the invention to provide a precombustion chamber construction for engines of the character described, which is economical to manufacture and assemble.

Another object of the invention is to provide a cylinder head for compression ignition and the like engines in the form of a casting, which provides a mounting for a removable precombustion chamber unit, and which can be produced with a large measure of security against defects caused by gas pockets and shrinkage.

Another object of the invention is to provide a simple mounting for a fuel injection nozzle.

Another object of the invention is to provide, in an engine of the character described, a fuel injection nozzle which is mounted to promote desirable heat conditions atV the discharge end thereof.

1 Another object of the invention is to provide, in an engine of the character described, an improved method of maintaining the discharge end of a fuel injection nozzle at emcient operating temperatures.

Another object of the invention is to provide a mounting for fuel injection nozzles which promotes quick and facile replacement of one nozzle by another.

Another object of the invention is to provide a precombustion chamber construction for engines of the character described, in which proper heat conditions in the chamber are promoted by virtue of the method of assembly and mounting therefor.

precombustion chamber construction for engines of the character described in which the fuel spray is received on a heated surface, and is met by an incoming current of vair which'is heated by the portion' of the precombustionchamber through E Vwhich it passes'.

= Another object of the invention is to provide an improved method of fuel combustion in precombustin chambers for engines of the character described.v l Other objects will progresses.

appear as the description (Cl. 12S-33)' Description of figures Figs. 1 through 4 illustrate one form of the invention.

Fig. 1 is a fragmentary transverse vertical section through the axis of the cylinder.

Fig. 2 is a fragmentary sectional view taken in the plane of line 2--2 in Fig. 1.

Fig. 3 is a sectional view taken in the plane of the line 3--3 in Fig. 1.

Fig. 4 is a. sectional view taken in the plane of the line 4 4 in Fig. l. v

Fig. 5 is a schematic view of the precombustion chamber. Fig. 6 is a fragmentary sectional View similar to Fig. l and illustrates the preferred form of the invention.

Fig. 'l is a view similar to Fig. 6 illustrating a third form of the invention. Fig. 8 is a fragmentary section similar to Fig. 6 illustrating a fourth form oi the invention.

Fig. 9 is a fragmentary sectional view similar to Fig. 6 illustrating a fifth form of the invention.V

Description of mechanism The compression ignition and the like engine disclosed herein is of the precombustion chamber type, which comprises generally a main combustion chamber, and a precombustion chamber in restricted communication therewith. Measured amounts of fuel are injected into the precombustion chamber of each cylinder by means of a. fuel injection nozzle, which'is preferably provided with a single hole discharge orice and is preferably operated by differential pressure from an associated fuel injection pump. For a complete disclosure of this type .of engine, reference is made to my copending application, Serial No. 684,179, filed August 8, 1933. Only that portion of the l engine necessary for an understanding of the present invention will now be described.

Engine block i0 (Fig. l) has head Il suitably secured thereon. Each cylinder is formed by a cylinder liner i2, suitably mountedin block l0 and having piston I3 mounted therein to form main combustion chamber I4 between bottom wall I5 of cylinder head Il and the dished top of piston I3. The cylinder head is a metal casting which is formed to provide amounting for a unit assembly in which the precombustion chamber is formed.

Cylinder head Il` is provided with internal cylindrical wall IB (Fig. 1) surrounded by water jacket or space I1; wall I6 having inner cylindrical surfaces I8, I9, of differing diameters to provide annular seat or shoulder 2| therebetween. A removably positioned precombustion chamber unit 26, the construction of which is described more specifically hereinafter, is provided with external

cylindrical surfaces

21, 28 of different diameters to provide annular seat or shoulder 29 therebetween for support on wall seat 2|. Sealing washer 3I, of any suitable metal having high heat conductivity such as copper for example, is placed between seats 2| and 29. Surface 21 of precombustion chamber unit 26, and wall surface I8 are, machined to iit closely, while unit surface 28 is of less diameter than wall surface I9 to provide annular space 32 (Figs. 1 and 4) therebetween for a purpose later described. The size of space 32 in the drawings is exaggerated for the purpose of clear illustration; the clearance between surfaces I9, 28 in the actual engine construction being in the order of .003-.005 of an inch. At the top, cylinder head II (Fig. 1) is provided with annular shoulder or seat 36 axially aligned with wall I6 to support annular flange 31 of unit 26; gasket 38, of rubber composition or other suitable. compressible material, being interposed between seat 36 and flange 31.

Because of the provision of the separate precombustion chamber unit 26 within the space or passage enclosed by wall I6, the internal diameters of such space must necessarily be larger for a precombustion chamber of a predetermined size than would be the case if the separate unit 26 were not employed. Hence, the cores used in casting wall I6 as part of the cylinder head will be larger than would obtain without employing separate unit 26. This enables a large measure of security against casting defects caused by gas pockets and shrinkage, because, in casting, the larger the cores the less chance for such defects.

Precombustion chamber unit 26 is formed of two molecularly united members, which can be readily machined to the desired form and dimensions before being welded together. Unit 26 includes lower member 4I and upper member 42 molecularly united at 43 by welding. Lower member 4I is formed to provide the precombustion chamber proper, while theupper member 42 provides mounting means for the fuel injection nozzle having its single hole discharge orifice axially aligned with the precombustion chamber axis. Upper member 42 is provided with a central bore forming small cylindrical wall surface 44 at the bottom, and seat 46 located between surface 44 and cylindrical wall surface 41 of larger diameter than surface 44. Fuel injection nozzle 5|, provided with differential pressure operated discharge needle 52, seats, with just enough clearance to provide a free fit, within surface 44 and, with minimum clearance to provide a close t, within surface 41; seat 53 of the nozzle being spaced from seat 46 of unit 26 by metallic gasket 54. Nozzle 5| is rigidly clamped in place by fitting 56 (Figs. 1 and 2) engaging the top thereof, and by studs 51 threaded in cylinder head I I and -passing through fitting 56. Suitable nuts are threaded orsi the upper ends of studs 51 to engage fitting 5 Means are provided for cooling the fuel injection nozzle, and for this purpose cylinder head wall I6 (Figs. 1 and 3) is provided with a plurality of vertically'elongated apertures 6I leading from water space |1 to water space 62 formed by recessed Wall portion 63 of upper member 42 that the wall of upper member 42 covers or shields the apertures 6|, and is in sealed contact with the solid walled portion I6 of the passage in the cylinder head. Since wall member 42 provides a mounting for the injection nozzle, the nozzle may be readily removed for replacement or repair without the water in water space I1 entering the auxiliary or precombustion chamber proper. Hence, the head need not be drained freel of water when any of the `nozzles are removed. As clearly seen in Fig. 1, a metallic path of heat flow is provided through the nozzle, from the discharge end thereof to upper member or unit part 42, via seats 53, 46 and metal gasket 54, and via wall surface 41 having the close fit with member 42; and from said member 42 heat is readily conducted to cooling chamber or water space 62. Cooling of the nozzle reduces to a minimum formation of carbon around the discharge orifice of discharge needle 52', caused by excessive heating of fuel which clings to the nozzle after injection terminates. Thus, clogging of the nozzle discharge orifice is substantially obvlated. Also, sticking or binding of the nozzle needle is prevented, which might otherwise occur by expansion of the metal caused by heat of combustion.

The precombustion chamber proper includes three different portions of differing size; one'of which provides a relatively large combustion space at the top and which is adjacent the discharge end of the fuel injection nozzle and is relatively cool, heat being transmitted from the walls thereof by conduction directly to Water spaces. The second of these portions is a funnel-shaped passage having a relatively hot wall which receives the injected fuel, and by virtue of the heated condition thereof aids in combustion of the fuel. The third portion is a small passage, to provide for ingress of air from the combustion chamber which is heated ln passing therethrough, and for discharge of the combustible mixture into the main combustion chamber. The second and third portions of the precombustion chamber are cooled only by radiation and convection as no direct metallic path of heat conduction to water spaces is provided. Lower member part 4| of unit 26 is provided with relatively large diameter inner/'cylindrical wall surface 66 to form the air supply or combustion chamber which is joined by comparatively short frusto-conical wall surface 61 to comparatively long frusto-conical wall surface 68, forming a funnel shaped fuel receiving chamber. The small diameter end of wall surface 68 merges with cylindrical wall surface 69. Wall surface 69 provides a cylindrical passage which communicates with main combustion chamber I4 through a plurality of restricted orifices 1I. Oriiices 1I, having .139"-.141" diameters, are inclined at an angle of substantially 45 with respect to the axis of the precombustion chamber and are formed in a wall section whose thickness should be from one and one-half to two times the diameter of the orifices, to obtain efficient results in controlling the flow of air and gasied fuel therethrough, as described later.

To promote efficient combustion, the total volume of the precombustion chamber, namely that portion enclosed 'by

wall surfaces

66, 61, 68 and 69, should be from 25% to 32% of the total clearance volume; the total clearance volume being defined as the total volume of the precombustion chamber together with the total volume of main of unit 26. In this connection, it will be uOted combustion chamber I4 when pStOn I3 iS at the end of its compression stroke or, in other words,

surface 69 is not critical; it being only necessary to have the chamber formed by surface 66 of a volume sumciently large to enable thorough intermixing of vaporized fuel with the air forced into the chamber during the compression stroke of the piston. Also, the chamber formed by surface 66 should be sufficiently deep to allow substantial conical spreading of the fuel jet or cone indicated by dotted lines in Fig. 5; and the funnel-shaped chamber formed by surface 68 should be wide enough at the top to have the fuel cone strike directly against the upper half of surface 68 for a reason to be subsequently explained.

Although the ratio of the volumes of the chambersA formed by

surfaces

66, 68 and 69 is not critical for efficient combustion, I have made the important discovery that certain cross sectional areas of the precombustion chamber should reduce in size in a denite ratio, from the tip of nozzle 5I to main combustion chamber I4, for most elcient combustion. I have found the following ratios preferable. (See Fig. 5.) A (the cross sectional area within wall surface 66): B (the cross sectional area. at the upper end of wall surface 68): C (the cross sectional area within wall surface 69)::25:5:1. Tho'ugh the foregoing ratios Vare preferable, I have found that satisfactory results can be obtained within the following limits: A:B:C::(30 to 22) :(5.5 to 5) :1. The value of A is such that a suicient oxygen carrying envelope is provided around the fuel spray jet or cone, indicated in dotted lines in Fig. 5, to insure combustion of the proper quantity of fuel in the precombustion chamber. The

values of B and C are selected, so that the center of the fuel spray cone, which is the hardest part to burn because it is shielded by the outer portion of the cone, is met by the incoming current` of heated air which is forced by the ascending piston, from the main combustion chamber I4 through the passage dened by wall surface 69. As was stated previously, the funnel-shaped portion of the precombustion chamber, that is, the portion defined by frusto-conical surface 68, is so positioned with respect to the nozzle that .the spray cone impinges on the upper half thereof at all times, irrespective of variations of pressureor amount of fuel injected. As a result, the center of the fuel spray cone is always thoroughly mingled with the inrushng heated air which, before encountering the fuel, -is subjected to heating from the hottest part of the precombustion chamber wall surface, i. e., surface 69 because of thev heat insulation which space 32 (Fig. 1) provides.

The `outside dimensions of the precombustion chamber unit 26 are selected to insure the most advantageous thermal conditions, by providing ceives the conical spray of fuel discharged from nozzle 5I, is maintained at a sufficiently high temperature to insure ready vaporization and combustion of the fuel. As wall portion 12 is cooled only by radiation and convention,- it affords an efficient means for heating the air forced into the precombustion chamber, to overcome the cooling effect caused by expansion of the air after passing through orices 1I. Wall I6 of the cylinder head has surface to surface contact at 21 with the upper part of the precombustion chamber defined by surface 66, to promote the dissipation of excess heat from the portion of the chamber adjacent nozzle 5I, whereby nozzle 5I is maintained at efcient operating temperatures.

It will be noted that the insulated wall portion of the auxiliary or precombustion chamber includes both the funnel-shaped passage or chamber defined by surface 68 and the axially extending cylindrical or tubular passage dened by wall "1 surface 69, and that the thickest part of wall 12 is at the main combustion chamber end about tubular passage 69. Such tubular passage, which is in restricted communication with the main combustion chamber, is the channel of least diameter in the precombustion chamber, and is much longer than its width. Furthermore,` the total cross sectional thickness of metal about such channel is greater than the width of the channel. 'This arrangement provides for mimimum expansion of the air entering the auxiliary combustion chamber, which would cause cooling thereof, and for maintaining such air hot in its flow through passage 69, so as to have no adverse effect on the vaporization of fuel striking the hot funnel-shaped passage 68. At the same time, as previously expained, the fuel becomes readily vaporized upon striking the funnelshaped passage. Furthermore, when gases of combustion leave the precombustion chamber, they are not cooled in their passage through tubular passage 69, and this avoids undesirable condensation of ignited fuel which might otherwise occur in such constructions having a comparatively wide thin walled` passage leading to the main combustion chamber.

From the preceding, it is seen that the portion of the precombustion chamber adjacent nozzle 5I, is not unduly overheated by virtue of the direct heat transfer to the solid wall within water jacket I1 to preclude damage to the nozzle which might be caused by excessive heat. Also,v by virtue of insulating space 32 and the wall thicknesses of the precombustion chamber surrounded by such space, the incoming air through the passage at surface 69 and the portion of the fuel cone which strikes surface 68, are maintained sufficiently hot for efficient combustion and vaporization of fuel. However, because of the presence of insulating space 32 about wall portion 12 and because the first direct transference of heat from insulated wall portion `12 to the cooling jacket is at gasket 3| some distance from the main combustion 4chamber end of the precombustion chamber, the thickness of wall porp tion 12 per se must also be so designed, as to provide for properl temperature conditions in wall portion 12 and to provide for sufficiently rapid transference of heat from location V (Fig. 5) adjacent orifices 1I; it being apparent that the wall portion adjacent orifices 1I is subjected to the direct heat of the main combustion flame in main combustion chamber Il. Therefore, heat must be' rapidly conducted away from location V to prevent burning out of the metal adjacent orifices 1l.

I have found that the temperature at V should not rise above 1100 F. Therefore, the thickest portion K of wall i2 ls made suiiiciently thick, so as to provide for a rapid transference and large path of heat flow from adjacent point V, and also for a temperature of about '150-8001 F. at portion K. Furthermore, the thick construction of wall portion 12 provides a sufficient amount of metal which forms a heat reservoir to cooperate with the insulating space 32, in maintaining the combustion chamber end of the auxiliary com-y bustion chamber hot. During flow of heat from point K to point S, (namely that portion of the precombustion chamber adjacent the widest part of funnel-shaped chamber 88 just before the point where direct transference of heat is made to the water jacket i1) the temperature necessarily drops. However,\it is not desirable for maximum combustion efficiency under full load and full speed operating conditions of the engine, to have the temperature at portion S fall below 400450 F. Consequently, portion S is made sufficiently thin to form a restricted neckand thereby provide a restriction to the flow of heat and to maintain the desired temperature at location S.

Thus, the restricted neck at S, throttles the dropping too low at funnel-shaped part 88, which would prevent proper vaporization of the fuel striking the funnel-shaped part. It will be noted that the wall thickness of the restricted neck is generally less than that of the wall thickness of funnel-shaped part 88, and that the restricted neck tapers or becomes narrower as it approaches the point at shoulder 2l where direct transference of heat is made to the water jacket I1to facilitate the heat throttllng effect.

The temperatures given above are those occurring in the particular engine in which' the precombustion chamber is employed. Such temperatures may vary in dinerent types of engines. However, depending upon the type of engine, one skilled in the art can readily employ the principles of construction described to obtain the results ofthe present invention; such principles lying severally or collectively in the insulating space 82 about wall portion 12, the direct transfer of heat to the water jacket in the widest portion of the precombustion chamber, namely, the portion adjacent the nozzle, the relatively thickwall portio'n 1! adjacent orifices 1I, the restricted neck portion S adjacent the widest portion of fuiel-shaped part. "fand the area and volume relationships ofsurfaces 88, 8l and 8l and the fuel cone, as was explained with reference to Fig. 5. In this connection, Fig. 5 is a full scale drawing of the precombustion chamber described, and, consequently, illustrates the preferred relationship of all surfaces and walls.

The combustion process .will now be described brieny. Upward movement of piston |8-(Fig. 1) compresses air in main combustion chamber il which has access to the precombustion chamber through holes or 'orifices 1I. About 15 before top dead center of the compression stroke, pressure is applied to the fuel in the fuel supply line by a fuel injection pump to cause nozzle Ii to begin introducing the fuel charge into the precombustion chamber. Fuel is introduced in the form of a conical spray which strikes the upper half of frusta-conical wall Il, which is mainls tained at a high temperature by virtue of the flow of heat to preclude the temperature from varying thickness of `wall 12 and annular space 32 insulating wall 12 from wall I6. The interior of the conical spray is met by a stream of air forced up through restricted orifices 1|. Expansion of the air passing through orifices 1| occurs as it enters the cylindrical passage defined by wallv surface 89. Cooling of the air would, therefore, normally obtain. However, by virtue of the insulated space 32 which maintains wall portion 12 hot, the expanded air is heated by hot ywall portion 12 to enhance efficient combustion.

The fuel spray cone impinges on the upper half of wall 68 so as to meet the full incoming air stream, and thereby provide maximum contact of the interior portion of the fuel cone with the air stream. Y

At about 8 before top center, ignition takes place in the precombustion chamber solely due to the vaporized condition of the fuel injected therein and the temperature existing therein. Inasmuch as the total volume of the precombustion chamber is only a small proportion of thetotal com-l bustion chamber space, preferably between 27% to 30%, only a limited amount of fuel can be consumed in the precombustion chamber space, such amount being substantially 20% of the fuel introduced for the full load charge.

'Remaining fuel introduced is shattered by the explosion of the preliminary portion of introduced fuel, whereby the remaining fuel charge is gasified. The increased pressure existing in the precombustion chamber space, due to the explosion therein, causes a flow of gasifled fuel down through the channel defined by frusto-conical' wall surface 68 and cylindrical wall surface 69, and out through openings 1I into the main combustion space. Fuel which emerges from openings 1i is of a gaseous nature, moving at a high velocity with cons iderable turbulan'ce. 'I'he charge of fuel is introduced into a swirling current of air in the main combustion chamber Il repair thereof is necessary. Further, the nozzle y construction and mounting, and the precombustion chamber construction provide for more efiicient cooling of the discharge end of the nozzle than is the case with respect to the construction of Fig. 1.A Precombustion chamber unit 8| is generally similar to unit 26 described above, and is similarly mounted in head i I. Unit 8i includes lower member 82 and upper member 83 which are mol'ecularly united at 84 by welding; upper member 83 having annular flange 86 vextending within and closely fitting wall 81 of member 82. Lower member 82 has respective cylindrical wall surfaces 88, 88 and frusto-conical wall surfaces '80, 8i, similar to respective wall surfaces 68, 89, 81 and 88 of the construction shown in Fig. 1. At the top of the cylindrical wall surface 88, upper member 88 has frusto-conical surface 92- forming a part of the top wall of the precombustion chamber; and immediately adjacent thereto and facing in the opposite direction, s'ecy In this connection, member 83 serves the same as member 42 in Fig. 1, t`o shield the apertures through which water from the water jacket passes to cool the nozzle.

The nozzle assembly, which is mounted as a unit in the precombustion chamber unit, comprises a nozzle and an adapter therefor, which are preadjusted with respect to each other before assembly on the engine, to prevent any undue stresses at the discharge end of the nozzle which would interfere with proper fuel spray characteristics, or prevent proper seating of the spray needle. Nozzle 94 (Fig. 6) fits freely within adapter 96, and hasthreaded engagement therewith at 95; lower end 91 of nozzle 94 engaging inwardly projecting annular lip 98 of adapter 96. Thus, theadapter member also serves as a nut to secure separate parts of the nozzle structure together, by virtue of the threaded connection 95. Pin 99 inserted through a suitable aperture ln adapter 96 engages a vertical slot in nozzle 94 to m-aintain accurately nozzle 94 in its preadjusted position in adapter 96. Adapter nut 96 is provided at the bottom as an integral part thereof with frusto-conical seat which rests on seat 93 of the precombustion chamber unit. The angular position of adapter 96 with respect to unit 8| is xedly maintained by engagement of splined portions |02, |03 of adapter 96 and upper member 83. Frusto-conical surface |04 on adapter 96 adjacent frusto-conical seat |0| provides a continuation of frusto-conical surface 92 of upper member 83, 'to form the top wall of the precombustion chamber. Shield |05 on nozzle 94 extends outwardly over the joint between adapter 96, and unit 8| to prevent the entry of deleterious matter between the parts.

From the foregoing description, it is seen that adapter 96 also has an integral lip or shield portion 98 in overlapping annular engagement with discharge end 91 of nozzle 94, providing a direct metallic path of heat flow which diverges outwardly and downwardly therefrom, through upper member 83 at |06, and to water space |01 positioned below discharge end 91 of nozzle 94.

Such positioning of water space |01 in cooperation with the metallic path of heat 4flow provided, enables ecacious coolingof the nozzle. The area of the nozzle discharge end exposed to the llame of combustion is materially less than the annular area of the discharge end contacted by seat 91, being less than half as can be seen from Fig. 6. The cross section of the path of heat ow increases as it diverges outwardly and downwardly; the area of seat |0| being several times greater than the area of -the seat at 91, the ratio of the areas being about 7 to 1. The metallic path of heat vflow is preferably proportioned so that the temperature of the discharge end of the nozzle is maintained below 400 F.

By virtue of the downwardly extending and increasing metallic path of heat flow, heat is readily conducted away from the discharge end of the nozzle without passing up through the nozzle body, thereby maintaining said discharge end at a sufficiently low temperature to decrease substantially formation of carbon deposits by the action of the heat of combustion of dribbled fuel. Nozzle 94'is clamped in position by means inf cluding clamp bar 56', similar in construction to the arrangement disclosed in Figs. 1 and 2 vfor clamping nozzle 5| in position. The provision of the described adapter nut 96, which is pre-lassembled and pre-adjusted with respect to the associated nozzle, provides a quick and simple method of installing or removing the nozzle in relation to the precombustion chamber. Also, the preadjusted nozzle assembly provides for ready interchangeability of the nozzle by another nozzle, which can be accomplished by unskilled operators at places remote from expert service facilities inasmuch as the preadjustment of the adapter and nozzle can be made at the factory.

The modification shown in Fig. 7 is generally similar to that described in connection with Fig. 6, particularly as to the construction and mounting of the precombustion chamber unit in relation to the cylinder head. In Fig 7, upper mem`- ber and lower member ||2 of the precombustion chamber unit are integrally joined by welding ||3. Upper member has annular projection 4 at the bottom, fitting closely within lower member ||2, and has frusta-conical seat formed therein for receiving the fuel nozzle assembly. Such fuel nozzle assembly includes adapter I1 having frustro-conical seat ||8 adjacent the bottom thereof and engaged with seat I6; while at the top adapter ||1 has a press t at ||9 within upper member At its lower end, adapter ||1 has flange or wall 22| having a central aperture. Wall |2| overlaps the lower end of the nozzle to form a shield therefor; and annular seat |22 is provided on the top of wall |1| for engagement by the discharge end of nozzle |23. Nozzle |23 has threaded engagement at |24 with adapter ||1. From the foregoing description, it is seen that in the modification shown in Fig. 7, many of the advantages noted in connection with the structure shown in Fig. 6 are obtained. However, the Fig. '7 modification does not provide the same degree of cooling eiciency at the discharge end of the nozzle as that in the Fig. 6 arrangement.

Fig. 8 illustrates a fourth modification which is primarily the same as that illustrated in Fig. 6, differing only in the adapter construction for mounting the nozzle. In Fig. 8, nozzle |3l is provided at the bottom with frusto-oonical seat |32 which is engaged with corresponding frustoconical seat |33 in adapter |34.

Fig. 9 illustrates a type of construction in which the precombustion chamber proper is formed directly in a Wall of the cylinder head. With such construction, the advantageous nozzle mounting referred to in connection with Figs. 618 is obtained by-adapter means similar to those described in the preceding portions of the specication. Head |4| (Fig. 9) is generally similar to the head construction illustrated in Figs. 1 through 4, and includes internal cylindrical wall |42 which has cylindrical internal wall surfaces |43, |44, |45 and |46 of decreasing diameter. Burner tube |41 is seated against shoulder |48 between wall surfaces |45 and |46, and at the top engages wall surface |45. At its lower end, tube |41 is threaded Within wall surface |46, and is provided adjacent its end with a plurality of orices or openings |49 providing for egress of gasiiied fuel from the precombustion chamber to the combustion chamber and for ingress of air into the precombustion chamber. Slots |50 at the top of tube |41 provide means for engagement with a suitable tool for effecting screwing of tube |41 in wall surface |46. The inner Wall surfaces of burner tube |41 converge conically from the top `to a cylindrical portion closed at its lower end, except for openings |49. y

A removable assembly is provided for closing the top of the precombustion chamber, and for mounting the discharge orice of the fuel injection nozzle in axial alignment therewith. Wall surfaces |43 and |44 (Fig. 9) have seat |52 formed therebetween, to receive corresponding seat |53 of fitting member |54, a suitable metallic gasket being interposed. N'Iember |54 ts closely within wall surface |43 atthe top, and gasket |55, of rubber or other suitable material, is provided to seal the engagement therebetween. Intermediate its end portions, member |54 is recessed at |51, to provide water jacketing inside of wall surface |43 and closely adjacent the discharge end of the nozzle. Adapter 95 and nozzle 94 are identical with those shown in Fig. 6 and are similarly mounted. However, the same cooling effect of the nozzle is not obtained as in the Fig. 6 modiy ilcation, by virtue of the absence of the metallic path of heat flow which diverges outwardly and downwardly to cooling iluid below the discharge end of the nozzle. .l

The above-described construction of Fig. 9 provides for cooling of the discharge end of the nozzle by means of an assembly which can be readily assembled in engines already manufactured which do not employ precombustion4 chamber units of the character disclosed in Figs. 1 through 8. It is to -be noted that respective adapters 96 and nozzles 94 which make up the fuel injection assemblies in Figs. 6 and 9 are identical, clearly demonstrating the'interchangeability of such assemblies provided by the consaid jacket; and an auxiliary combustion chamber in the substantially solid walled portion of said passage, an end portion of said auxiliary combustion chamber adjacent said main' combustion chamber being out of contact with said wall to provide a substantially annular insulating space between said end portion and said wall and which is in communication with said main combustion chamber whereby a suitable amount of heat is maintained in said end portion for combustion of fuel and heating of air, said insulated end portion of said auxiliary combustion chamber including a tubular passage of greater length than width extending axially of the auxiliary combustion chamber and in communication with said main combustion chamber, and also a funnelshaped part adapted to receive sprayed fuel thereon and which is in communication with said tubular passage, the side wall of said insulated portion being relatively thick at the end thereof adjacent said main combustion chamber and the total cross sectional thickness of the metal about said tubular passage being greater than the width of the passage to cooperate in maintenance of heat and to conduct heat away rapidly from the hot main combustion chamber end, the metal leading fromadjacent the wide portion of said funnelshaped part being arranged to provide a restriction to the flow of heat from such funnel-shaped part and thereby maintain the funnel-shaped part at a temperature enhancing vaporization of the fuel sprayed thereon.

2. In a compression ignition and the like engine,l a main combustion` chamber; a cooling fluid jacket having a walled passage therethrough communicating with said main combustion chamber, the end portion of the wall adjacent said main combustion chamber being substantially solid and the opposite end portion of said wall being apertured to admit cooling fluid from said jacket; and an auxiliary combustion chamber in the substantially solid walled portion of said passage, an end portion of said auxiliary combustion chamber adjacent said main combustion chamber being out of contact with said wall to provide a substantially annular insulating space between said end portion and said wall and which is in communication with said main combustion chamber whereby a suitable amount of heat is maintained in said end portion for combustion of fuel and heating of air, said insulated end portion of said auxiliary combustion chamber including a tubular passage of greater length than width extending axially of the auxiliary combustion chamber and in communication with said main combustion chamber, and also a funnelshaped part adapted to receive sprayed fuel thereon and which is in communication with said tubular passage, the side wall of said insulated end portion about said tubular passage being the thickest part of the entire auxiliary combustion chamber wall and the total cross sectional thickness of the metal about said tubular passage being greater than the width of the passage to cooperate in maintenance of heat and to conduct heat away rapidly from the hot main combustion chamber and, the metal portion leading from adjacent the wide portion of said funnelauxiliary combustion chamber leading from said metal portion being in heat conducting contact with the wall of said passage.

3. In a compression ignition and the like engine, a mainI combustion chamber; a cooling uid jacket having a walled passage therethrough communicating with said main combustion chamber, the end portion of the wall adjacent said main combustion chamber being substantially solid and the opposite end portion of said wall being apertured to admit cooling fluid from said jacket; an auxiliary combustion chamber in the substantially solid walled portion of said passage, an end portion of said auxiliary combustion chamber adjacent said main combustion chamber being out of contact with said wall to provide a substantially annular insulating space between said end portion and said wall and which is in communication with said main combustion chamber whereby a suitable amount of heat is maintained in said 'end portion for combustion of fuel and heating of air, said insulating end por- ,tion of said auxiliary combustion chamber inand thereby maintain the funnel-shaped part at a temperature enhancing vaporization of the fuel sprayed thereon, another portion of said auxiliary combustion chamber leading from said metal portion being in heat conducting contact with the wall of said passage; a fuel injection nozzle assembly in said passage adjacent the apertured wall portion thereof; and means shielding the discharge end surface of the nozzle from heat of combustion and providing a path for conducting heat away from said surface to the cooling fluid admittedthrough the apertured Wall portion.

4. In a compression ignition and the like engine, a main combustion chamber; a cooling fluid jacket having a walled passage therethrough communicating with said main combustion chamber, the end portion of the wall adjacent said main combustion chamber being substantially solid and the opposite end portion of said wall being apertured to admit cooling fluid from said jacket; an auxiliary combustion chamber in the substantially solid' walled portion of said passage, an end portion of said auxiliary combustion chamber adjacent said main combustion chamber being out of contact with said wall to provide a substantially annular insulating space be# tween said end portion and said wall and which is in communication with said main combustion chamber whereby a suitable amount of heat is maintained in said end portion for combustion of fuel and heating of air, said insulated end portion of said auxiliary combustion chamber including a funnel-shaped part adapted to receive sprayed fuel thereon, the side wall of said insulated end portion being relatively thick at the end thereof adjacent said main combustion chamber to cooperate in maintenance ofheat'and to conduct heat away rapidly from the hot main combustion chamber end, the metal portion leading from the wide portion of said funnel-shaped part being arranged to provide a restriction to the flow of heat from such funnel-shaped part and thereby maintain the funnelshaped part at a temperature enhancing vaporization of the fuel sprayed thereon, another portion of said auxiliary combustion chamber leading from said metal portion being in heat conducting contact with the wall of said passage; a fuel injection nozzle assembly in said passage adjacent the apertured wall portion thereof; and means shielding the discharge end surface of the nozzle from heat of combustion and providing a metallic heat conducting path converging downwardly and outwardly from said surface to the cooling fluid admitted through the apertured wall portion.

5. Auxiliary` combustion chamber means adapted to be positioned in a walled passage through the fooling fluid jacket of a compression ignition and the like engine in communication with the main combustii chamber of said engine, comprising a walled member adapted for positioning adjacent said main combustion chamber out of contact with the wall of said passage to provide a substantially annular insulating space between said member and the Wall of said passage which is adapted to communicate with said main combustion chamber, the insulatable portion oi' said walled member including a tubular passageof greater length than width extending axially of the auxiliary combustion chamber and adapted to have communication with the main combustion chamber, and also a funnel-shaped part adapted to receive sprayed fuel thereon and which is in communication with said tubular passage, the side wall of said member about said tubular passage vbeing relatively thick adjacent the main combustion chamber end thereof to provide a total 'cross sectional thickness of the metal about said tubular passage greater than the width of such passage, the metal leading from the wide portion of said funnel-shaped part being arranged to throttle flow of heat from such funnel shaped part.

6. In a compression ignition and the like engine, a main combustion chamber; a cooling fluid jacket having a walled passage therethrough communicating with said main combustion chamber, the end portion of the wall adjacent said main combustion chamber being substantially solid; an auxiliary combustion chamber in the substantially solid walled portion of said passage including a tubular passage of greater length than width extending axially of the auxiliary combustion chamber and in communication with said main combustion chamber, and-a funnel-shaped part adapted to receive sprayed fuel thereon and which is in communication with said tubular passage, the side wall of said auxiliary combustion chamber about said tubular passage being relatively thick to provide a total cross sectional thickness of the metal about said tubular passage greater than the width of the passage to cooperate in the maintenance of heat and to conduct heat away 'rapidly from the hot main combustion chamber end of said auxiliary combustion chamber; sleeve means above said auxiliary combustion chamber providing a shield for the cooling fluid to prevent access of cooling fluid to said auxiliary combustion chamber; an inwardly projecting seat in said Walled passage for fuel injection means adapted to be positioned in said sleeve means whereby the fuel injection means may be readily removed without leakage of fluid into said auxiliary combustion chamber and said seat may be cooled by said cooling fluid to conduct heat away from said seat; and fuel injection means removably mounted on said seat comprising a fuel inje'ction nozzle assembly held together by an adapter nut, said adapter nut having a lip portion integral therewith engageable with said seat and in overlapping engagement with the discharge end surface of the nozzle for shielding and providing a path for ilow of heat from such surface. l

7. In a compression ignition and the like engine, a main combustion chamber; a cooling fluid jacket having a Walled passage therethrough communicating with said main combustion chamber, the end portion of the wall adjacent said main combustion chamber being substantially solid; an auxiliary combustion chamber in the substantially solid walled portion of said passage including a tubular passage of greater length than width extending axially of the auxiliary combustion chamber and in communication with said main combustion chamber, a funnel-shaped part adapted to receive sprayed fuel thereon and which is in communication with said tubular passage, and another tubular part in communication with said funnel-shaped part and of greater width than the wide portion of said funnel-shaped part, said tubular passage and said funnel-shaped part being insulated from the wall of the jacket passage and said another tubular part being in heat conducting contact with the wall of the jacket passage-the side wall of said auxiliary combustion chamber about said tubular passage being relatively thick to provide a total cross sectional thickness of the metal about said tubular passage greater than the width of the passage to cooperate in the maintenance of heat and to conduct heat away rapidly from the hot main combustion chamber end of said auxiliary combustion chamber; sleeye means above the wall about said another tubular part to prevent access of cooling iiuid to said auxiliary combustion chamber; an inwardly projecting seat in said walled passage for fuel injection means adapted to be positioned in said sleeve means whereby the fuel injection means may be readily removed without leakage of uid into said auxiliary combustion chamber and said seat may be cooled by said cooling iiuid to conduct heat away from said seat; and fuel injection means removably mounted on said seat comprising a fuel injection nozzle assembly held together by an adapter nut, said adapter nut having a lip portion integral therewith engageable with said seat and in overlapping engagement with the discharge end surface of the nozzle for shielding and providing a path for flow of heat from such surface.

8. Auxiliary combustion chamber means comprising a walled portion including a tubular passage extending axially lof such chamber and adapted for communication with a main combustion chamber of a compression ignition and the like engine, a funnel-shaped part adapted to receive sprayed fuel thereon and which is in communication .with said tubular passage, and a relatively large combustion space in communication with said funnel-shaped ,part and having a width greater than the wide portion of said funnel-shaped part, the tubular passage having a length along the axis of such .chamber which is greater than the width thereof, and the side wall about said tubular passage being relatively thick to provide a total cross sectional thickness of the metal about said tubular passage greater than the width of the tubular passage.

9. ,Auxiliary combustion chamber means comprising a walled member including a tubular passage extending 'axially of such chamber and adapted for communication with a main combustion chamber of a compression ignition and the like engine, a funnel-shaped part adapted to receive sprayed fuel thereon and which is in communication with said tubular passage, and another tubular part in communication with said funnel-shaped part'and of greater width than the wide portion of said funnel-shaped part, said funnel-shaped part and said another tubular part being joined by a section of metal which provides a' restriction for throttling flow of heat from said funnel-shaped part to said another tubular part, said tubular passage having a length along the axis of such chamber which is greater than the width thereof, and the side wall about said tubular passage being relatively thick to provide a total cross sectional thickness of the metal about said tubular. passage greater than the width of the tubular passage.

h 10. A precombustion chamber unit adapted to receive in its upper portion fuel injection means and provided at an intermediate point with an internal annular shoulder for seating said fuel injection means; a precombustion chamber below said annular shoulder including a passage extending axially of said chamber and adapted for communication with a main combustion chamber of a compression ignition or the like engine, a funnel-shaped part having the narrow end thereof in communication with such axial passage so as to taper outwardly therefrom and adapted to receive sprayed fuel thereon from fuel injection means supported in the upper portion of said unit, and a' relatively wide combustion space in communication with the wide end of said funnel-shaped part and having a Width greater than the wide end of said funnel-shaped part; the wall about said axial passage being relatively thick and of a cross sectional thickness greater than the width of the axial passage to cooperate in the maintenance of heat and to conduct heat away rapidly from the hot main combustion chamber end of said precombustion chamber, and the wall joined to the Wide end of said funnelshaped part being constricted to a relatively thin portion adjacent said relatively wide combustion space to provide a restriction for throttling ow of heat between said funnel-shaped part and said relatively wide combustion space.

11. A precombustion chamber unit adapted to receive in its inner portion fuel injection means and provided at an intermediate point with an internal annular shoulder for seating said fuel injection means; fuel injection means supported in the upper portion of said precombustion cham ber unit on said shoulder and comprising a fuel injection nozzle assembly held together by an adapter element, said adapter element having a lip portion integral therewith and in overlapping engagement with the discharge end surface of the nozzle for shielding and providing a path for flow of heat from such end surface; a precombustion chamber below said annular shoulder including a passage extending axially of said chamber and adapted for communication with a main com bustion chamber of a compression ignition or the like engine, a funnel-shaped part having the narrow end thereof in communication with such axial passage so as to taper outwardly therefrom and adapted to receive sprayed fuel thereon from said fuel injection means supported in the upper portion of said unit, and a relatively wide combustion space in communication with the wide end of said funnel-shaped part and having a width greater than the wide end of said funnelshaped part; the wall about said axial passage being relatively thick to cooperate in the maintenance of heat and to conduct heat away rapidly from the hot main combustion chamber end of said precombustion chamber, and the wall joined to the Wide end of said funnel-shaped part being j constricted to a relatively thin portion adjacent said relatively wide combustion space to provide a restriction for throttling flow of heat between said funnel-shaped part and said relatively wide' combustion space.

i CARL G. A. RosN.

Patent No. 2-,1,u8,'505.

CERTIFICATE CE CORRECTION.

.February 28, 1959- CARL G. A. ROSEN. v

It is hereby certified that error appear-erin the printedspecification of the above numbered patent requiring correction as'follows: Page 5, second column, line 5, for the word "convention" read convection; 1111657, for "expained" read explained; page h, first column, line 5, for "wall 12" read wall 72; page 5,'first column, line 68, for "of" before "dribbled" read on; and second coluxnn, line 25, for "wall 221" read wall 121; 'page -6`,second column, line 52, claim 2, for "and" read end; iine 60, vclaim 5t, for "insulating'" read insulated; page? first column, line 56, claim 5, for "fooling" read cooling; page 8,V second column, line 26, claimll, for "inner" read'upper; andthat the said Letters Patent should be read with this correction therein that the same may Conform to the record ofthe casein thev Patent Office.

signed and lsealed 'this 25th day of April, A.D. 1959.

Henry Van Arsdale (Seal) y Acting Commissioner of Patents.