US3534715A - Opposed piston engine having improved cylinder liner cooling - Google Patents

Description

United States Patent Anker K. Antonsen Merritt Island, Florida; Matthew L. Foreman, Beloit, Wisconsin [72] Inventors [21] Appl. No. 788,151

[22] Filed Dec. 31, 1968 [45] Patented Oct. 20, 1970 [73] Assignee Fairbanks Morse Inc. New York, New York a corporation of Delaware [54] OPPOSED PISTON ENGINE HAVING IMPROVED Primary Examiner-Mark M. Newman Att0meyGeorge A. Woodruff ABSTRACT: In an opposed piston engine having one opposed piston of greater diameter than the other and having the combustion zone of the cylinder assembly located in the cylinder liner receiving the lesser diameter piston, being in its end section communicating with the cylinder receiving the other piston, wherein said cylinder liner has its wall portion in said end section of materially reduced thickness relative to the remainder of the liner wall, and provides a plurality of ribs externally on the wall portion; a liner support frame affording a coolant fluid jacket about the liner and having an internal wall structure engaging the ribs for effecting adequate support of said liner wall portion against the axial and radial forces imposed thereon in engine operation, wherein the wall structure cooperates with the linear wall portion and said ribs to form passages opening to said jacket, for coolant fluid flow in direct heat absorbing relation to the liner wall portion, and the ribs being formed and arranged on the liner wall portion for cooperation with said wall structure such as to divide said passages into a plurality of separate pairs.

Patented Oct. 20, 1970 3,534,715

Sheet L of 3 INVE TORS l/vriefl firm/say 4447734514 1. Fave-MIN ATTORNEY Patented Oct. 2o, 1910 3,534,715

Sheet 2 Z1 of 3 ATTORNEY Patented Oct. 20, 1970 3,534,715

Sheet of s BY I M OPPOSED PISTON ENGINE HAVING IMPROVED CYLINDER LINER COOLING This invention relates to internal combustion engines of opposed piston type having one opposed piston of greater diameter than the other and wherein the cylinder combustion zone is defined by the cylinder liner receiving the lesser diameter piston, in its end section communicating with the cylinder portion receiving the greater diameter piston. More particularly, the invention concerns improvements providing for more effective and efficient cooling of the cylinder liner in the region thereof affording the cylinder combustion zone.

In an engine of the character indicated providing for power output in the order of 1000 horsepower per cylinder, effective cylinder cooling in the combustion zone region presents a major problem, and particularly so in an engine of this character which is of compact construction. It is found that known and heretofore employed means for cylinder cooling in engines of lesser horsepower per cylinder, are inadequate for an engine of the high horsepower output here indicated.

It is, therefore, an object of the present invention to provide means for attaining effective cooling in the cylinder com bustion zone of an engine of the type and high horsepower per cylinder character hereinabove indicated.

Another object is to provide improvements in the com-' bustion zone defining cylinder liner and its supporting frame, for an opposed piston engine of high horsepower per cylinder character as aforesaid, affording reduced thickness of the liner wall portion in the combustion zone and a plurality of passages arranged for coolant fluid flow in direct, controlled heat ab sorbing contact with such liner wall portion, whereby to attain an effective degree of liner cooling over the combustion zone region thereof.

These and other objects and advantages of the present invention will be apparent as the description proceeds with reference to the accompanying drawings.

FIG. 1 is a generally diagrammatic view in section, as taken from line II in FIG. 2, of an opposed piston engine of the character hercinbefore indicated, embodying the present improvements;

FIG. 2 is an enlarged view of the combustion zone forming cylinder liner, appearing in transverse section as taken from line 2-2 in FIG. I; and

FIG. 3 is an enlarged, fragmentary detail view in sectional elevation through the cylinder liner and support frame, as taken along line 3-3 in FIG. 2.

FIG. 1 illustrates a stepped cylinder opposed piston arrange ment for single or multicylinder engines of the type and high horsepower per cylinder character as hereinbefore indicated, provided for operation on liquid fuel (as oil) or on gaseous fuel wiih ei'ihf's fia rk ignitionor piliit liquidfueli' nifion, or on both such fuels. As shown, the cylinder is comprised of cylinder liner members and 11, liner 10 being ofa given internal diameter and supported in main frame or engine block 12. Liner II coaxial with liner 10 and extending thereabove, has an internal diameter less than that of liner 10 to a predetermined extent, and is carried in an upper frame 13. The lower end section 14 of liner 11 presents an outwardly flaring portion 15 terminating in an annular mounting flange l6 seating on the top flange 17 of lower liner l0. Liner portion 15 has its internal surface 18 smoothly curved as shown, and such surface defines the combustion zone of the cylinder assembly (in cooperation with the pistons at inner positions).

Operating in liner 10 is a piston 19 of correspondingly large diameter, having connecting rod 20 extending to a lower crankshaft indicated at 22. A small or lesser diameter piston 23 opposed to piston 19, operates in liner 11 and as indicated schemmatically has its connecting rod 24 in operative connection to an upper crankshaft 26 through suitable linkage as rod 27 and rocker arm 28. The two crankshafts are interconnected by suitable gearing or other means (not shown), while the rocker arm linkage to piston 23 is such as to determine the full travel of that piston at one-half the full travel of piston 19.

The engine air ports 30 are in the liner 10 under control of the piston 19, and receive air from the supply manifold 31 in the main frame 12. In liner II are the exhaust ports 32 under control of the piston 23, and these ports open to an exhaust collector passage 34 provided in frame 13, passage 34 terminating in exhaust outlet 35. In the present example the engine is turbocharged, having the exhaust gases delivered over line 36 to the intake of turbine section 38 ofa suitable exhaust driven turbocharger 39 having an air compressor section 40. Pressure air is supplied from section 40 via line 42 to the engine air manifold 31.

In accordance with the present invention, the cylinder liner II is constructed such that its wall section 14 including the combustion zone defining wall portion 15 thereof. is of materially reduced thickness relative to the remaining wall portion, as 43, of the liner. Preferably and as indicated in FIG. 3. wall section I4 has a thickness appreciably less than onehalf the thickness of liner wall portion 43, whereby to provide for and assure a desirable high rate of heat conduction through the wall section to the liner exterior, for rapid heat removal with resultant cooling of the liner section by means presently to appear. Because of its relative thinness the liner wall section 14 is not self-supporting against the axial and radial forces imposed thereon consequent to fuel combustion and expansion, these forces being very considerable in an engine of high horsepower per cylinder character to which the present improvements have particular application. It is necessary therefore, to provide means fully adequate to support the liner wall section 14 and absorb the indicated forces, and such support is here afforded in an improved manner now to be described.

The liner 1] is formed to provide a plurality of integral ribs externally on the thin wall section 14, the ribs being generally equally spaced about the liner section and projecting substantially radially therefrom. The ribs which follow the contour of wall section 14 (FIG. 3), are arranged in two sets, one set comprising the ribs and the other the ribs 51 in an alternate relation to the ribs 50, as appears in FIG. 2. Ribs 50 are oflike form, each presenting a stepped outer face or margin as shown in FIG. 3. Such margin comprises the marginal portion 52 extending parallel with the liner axis and in line with the outer face 54 of the liner wall portion 43; marginal portion 55 extending parallel with the liner axis and radially outward of marginal portion 52; marginal portion 56 preferably linear in extent, inclined outwardly from the portion 55, and marginal portion 58 normal to the liner axis. Each rib 50 terminates in a smoothly rounded end wall 59 spaced inwardly from the inner side 60 of the liner flange l6, and has its marginal portion 58 substantially in the plane of the top surface 62 of the flange.

The ribs SI have outer stepped margins 52a, 55a and 56a (FIG. 2) identical with the corresponding stepped margins of ribs 50. However each rib 51 extends to integraljunction with the liner flange 16, as indicated at 63 in FIG. 2, and has its step margin 64 (FIG. 2) extending to mergence with the top face 62 of the liner flange.

As indicated in FIG. 2 the cylinder liner 11 having the cylinder combustion zone defined by the thin liner wall section 14 over portion 15 thereof, is formed to provide in that portion diametrically opposite apertured bosses 66 to receive fuel admission means as injection nozzles (not shown), and an apertured boss 67 for an air start valve (not shown), and an apertured boss 68 as for a pressure relief valve (not shown). Consequently, ribs 50 and 51 in the immediate region of each such boss are constructed to accommodate the associated boss. Thus in respect to each boss 66, ribs 50a and 5111 have portions thereof merging with the boss; at boss 67 the rib 50b is cut-away at 70 and the adjacent ribs 51b merge at one side into the boss, and at boss 68 portions of ribs 500 and 510 merge into the boss.

While the ribs 50 and SI materially strengthen the thin liner wall section 14, full support of that section against the heretofore noted radial and axial forces acting thereon, is here afforded by the liner receiving frame 13 through an internal frame structure 71 engaging the liner ribs. Frame 13 includes an outer wall 72 extending in spaced relation about the liner 11 and forming with the latter a coolant fluid jacket space 74,

wall 72 including an annular mounting flange 75 for seating on the main frame 12. Frame structure 71 formed integrally with the wall 72 at its end region adjacent flange 75, provides an annular wall portion 76 embracing the ribs 50 and 51 over the respective marginal portions 55 and 55a thereof, an intermediate inclined annular wall portion 78 embracing the ribs 50 and 51 over the respective marginal portions 56 and 56a thereof, and an annular wall portion 79 seating against the ribs 50 and 51 on the respective marginal portions 58 and 64 thereof, and extending to seating on the top surface 62 of the liner flange 16. Moreover, wall structure 71 is desirably braced against the outer frame wall 72 by a plurality of strengthening ribs or webs extending therebetween, one such rib being here shown as at 80 in FIG. 3. In the present exemplary embodiment there are as many ribs 80 as there are liner ribs 51, and the ribs 80 are desirably located such that each is in radial alignment with one of the ribs 51 (See FIG. 2) in the assembled condition of the liner and frame.

It will be apparent now from the foregoing that the frame 13 through its internal frame structure 71 engaging the liner ribs 50 and 51, affords with the ribs full support of the thin wall liner section 14 to maintain it against both axial and radial forces imposed thereon in engine operation. Referring to the sectional view of FIG. 3, it will be observed that in the present improved liner backing arrangement, wall portion 76 of the frame structure counteracts radial forces, while wall portion 78 counteracts components of radial and axial forces, and wall portion 79 counteracts axial forces.

Importantly in the present invention, the ribs 50 and 51, frame wall structure 71 and the liner flange l6 cooperate to provide a plurality of passages about the liner section 14 for flow therethrough of coolant fluid, as water for example, in direct heat absorbing contact with the thin wall liner section 14 and the ribs. According to the invention, these passages are related in pairs separate from one another, and coolant fluid is supplied thereto by admission means individual to the passage pairs. Referring to FIGS. 2 and 3, each passage pair comprises the passages 84 and 85 on opposite sides of a liner rib 50, so that the number of such paired passages corresponds to the number of ribs 50. In each pair, the inlet ends 86 and 88 of passages 84 and 85, respectively, are adjacent the inner wall 60 of the liner flange l6, and these inlet ends are in relative communication through the space 89 between the flange wall and the terminal end wall 59 of the rib 50. Passage 84 has its outlet end 90 (FIG. 3) in open communication with the adjacent region of the jacket space 74 in frame 13, and passage 85 likewise has its outlet end (not shown) open to the same jacket space region.

Provided in the liner flange 16 are a plurality of radial, coolant fluid admission passages 92, one for each pair of linear passages 84, 85. Each passage 92 is disposed to have its delivery port 93 opening to 89 in radial alignment with the terminal end wall 59 of the associated rib 50, whereby coolant fluid issuing through port 93 will be divided by the rounded end wall 59 for flow in separate substantially equal streams through the passages 84 and 85.

In the present embodiment, coolant fluid is supplied to the admission passages from the jacket system 94 (FIG. 1) of main frame or engine block 12, such system having fluid under pressure flow therein received from a suitable coolant fluid source (not shown). As exemplified in FIG. 3, the mounting flange 75 of frame 13 provides for each admission passage 92, a radial bore 96 for communication with passage 92 and an intersecting bore 97 open at the mounting face of the flange to receive a connecting duct 98, the latter being carried in the upper flange 100 (FIG. 1) of main frame 12 and open to the jacket system 94.

The illustrated and now described coolant flow arrangement affords highly effective cooling of the thin wall liner section 14, the effectiveness thereof being due in particular to the separation of the passages into independent pairs and the delivery of coolant fluid to the passage pairs by supply duct means individual to the pairs. Thus flow in each passage pair is removed from influence by the flow in the other pairs, which if otherwise permitted would tend to create flow turbulence or other disturbances productive of decreased heat absorbing and removal effectiveness of the coolant streams. Importantly herein, such separation of the passages into independent pairs permits attainment of both a desirable laminal flow and a high rate of flow in each passage of each pair, which in cooperation with rapid heat conduction through the thin liner section, results in a desired rapid rate of heat removal from the combustion zone defining liner section 14. Contributing to the result is the additional area of heat transfer in each passage afforded by the associated passage defining ribs.

Having now described and illustrated a presently preferred embodiment of the invention, it is to be understood that modifications may be made thereto without departing from the scope of the invention as hereinafter claimed.

I claim:

I. In an opposed piston engine wherein the opposed pistons are of different diameters, having a cylinder assembly including a cylinder structure for the larger diameter piston, a cylinder liner for the smaller diameter piston having an end section including an outwardly flared portion terminating in an annular mounting flange adjoining one end of the cylinder structure, said portion defining the combustion zone of the cylinder assembly, and a frame mounted on the cylinder structure for support of the cylinder liner, the improvement therein which comprises:

a. providing said cylinder liner to have the liner wall in said end section of reduced thickness extending to said mounting flange and to have a plurality of relatively spaced, integral ribs externally on said liner wall;

b. providing said frame to have an outer wall surrounding the cylinder liner and cooperating with the latter to form a coolant fluid jacket space, and to have an interior annular wall portion engaging said ribs, forming therewith coolant fluid flow passages along said reduced thickness liner wall and opening to said jacket space; said ribs being adapted and arranged for cooperation with said annular mounting flange to relate said passages in distinct passage groups separate from each other;

d. and means for supplying coolant fluid to said passage groups, said means including conduit means individual to said passage groups.

2. In an opposed piston engine as set forth in claim 1, characterized further in that the said cylinder structure includes a coolant fluid jacket, and the said conduit means individual to said passage groups extend to fluid supply connection with said jacket of the cylinder structure.

3. In an opposed piston engine wherein the opposed pistons are of different diameters, having a cylinder assembly including a cylinder structure for the larger diameter piston, a cylinder liner for the smaller diameter piston having an end section including an outwardly flared portion terminating in an annular mounting flange adjoining one end of the cylinder structure, said portion defining the combustion zone of the cylinder assembly, and a frame mounted on the cylinder structure for support of the cylinder liner, the improvement therein which comprises:

a. providing said cylinder liner to have the liner wall in said end section of reduced thickness extending to said mounting flange; to have a first set of equally spaced,

parallel ribs externally about said reduced thickness liner wall and extending therealong to junction with said mounting flange, and to have a second set of ribs paralleling the first set wherein each thereof is equally laterally spaced from an adjacent pair of ribs in the first set and terminated in an end wall spaced from said mounting flange;

b. providing said frame to have an outer wall surrounding the cylinder liner and cooperating with the latter to form a coolant fluid jacket space, and to have an interior annular wall engaging said first and second sets of ribs and cooperating therewith to form coolant fluid flow passages along said reduced thickness liner wall and opening to saidjacket space; and coolant fluid supply means including supply passages in said mounting flange wherein each such supply passage has an outlet port opposed to the end wall of one of said second set of ribs.

4. ln an opposed piston engine as set forth in claim 3, characterized further in that the said cylinder structure includes a coolant fluid jacket, and the said frame includes passageways communicating the said supply passages with said jacket of the cylinder structure.

5. In an opposed piston engine as set forth in claim 3. characterized further in that the said frame includes a plurality of rib elements extending between the said outer wall and interior annular wall of the frame, wherein each rib element is substantially in radial alignment with one of the ribs in the said first set of ribs.

6. in an opposed piston engine wherein the opposed pistons are of different diameters, having a cylinder assembly including a cylinder structure for the larger diameter piston, a cylinder liner for the smaller diameter piston having an end section including an outwardly flared portion terminating in an annular mounting flange adjoining one end of the cylinder structure, said portion defining the combustion zone of the cylinder assembly, and a frame mounted on the cylinder structure for support ofthe cylinder liner, the improvement therein which comprises:

a. providing said cylinder liner to have the liner wall in said end section of reduced thickness extending to said mounting flange; to have a first set of equally spaced, parallel ribs externally about said reduced thickness liner wall and extending therealong to junction with said mounting flange, and to have a second set of ribs paralleling the first set wherein each thereof is equally laterally spaced from an adjacent pair of ribs in the first set and terminates in an end wall spaced from said mounting flange;

b. providing said frame to have an outer wall surrounding the cylinder liner and cooperating with the latter to form a coolant fluid jacket space, and to have an interior annu lar wall engaging said first and second sets of ribs and seating on said mounting flange;

. said interior annular wall cooperating with said liner wall. the first and second sets of ribs and said mounting flange to form separate pairs of coolant fluid flow passages along said liner wall and opening to said jacket space. each pair of said passages comprising the passages on opposite sides of one of said second set of ribs, and the passagesof each pair being in communication between said mounting flange and the end wall of the associated one of said second set of ribs; and

d. coolant fluid supply means including supply passages in said mounting flange. said supply passages being individual to said pairs of coolant fluid flow passages, and each having an outlet port substantially opposite the end wall of the associated one of said second set of ribs.

7. In an opposed piston engine asset forth in claim 6, characterized further in that the said cylinder structure includes a coolant fluid jacket, and the said frame includes passageways communicating the said supply passages with said jacket of the cylinder structure.

8. in an opposed piston engine as set forth in claim 6, characterized further in that the said frame includes a plurality of rib elements extending between the said outer wall and interior annular wall of the frame, wherein each rib element is substantially in radial alignment with one of the ribs in the said first set of ribs.

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