US2446841A - Cylinder liner for opposed-piston engines - Google Patents

Description

ug. H0 1948. H UEBERHERR 2,446,841

CYLINDER LINER FOR OPPOSED-PISTON ENGINES Filed May 5, 1945 INVENTOR. b5; Z/ee/fie/r Patented Aug. 10, 1948 CYLINDER LINER FOR OPPOSED-PISTON ENGINES Hans Lieberherr, Winterthur, Switzerland, assignor to Sulzer Freres, Societe Anonyme, Winterthur, Switzerland Application May 5, 1945, Serial No. 592,232 In Switzerland May 8, 1944 7 Claims.

The invention relates to a cylinder liner for opposed-piston engines and consists in that the middle part, in so far as it is not swept by the piston rings, is provided with a heat protective ring and the parts of the liner situated on both sides of this middle part are subjected to intensive cooling by means of cooling passages.

An arrangement of the cylinder liner of an opposed-piston engine is known in which the cooling of the middle part is efiectedby means of holes bored obliquely to the axis, which lie nearest to the surface of the liner in the middle plane of the liner and on both sides of this plane again retreat from the surface. A solution of this kind is inexpedient in so far as the cooling is particularly desired at the point where the piston rings lie in the upper dead centre. Further, the openings for the threads. In other words, these valves may be fuel injection valves and the starting valves are in the middle plane. Special measures must therefore be taken so that the cooling medium can flow round these valves. A very broken-up cylinder liner is thus obtained, with uncontrollable concentrations of stress. The object of the invention is on the one hand to obviate these stress concentrations and on the other to obtain better cooling of the piston rings.

One embodiment of the invention is shown diagrammatically in the drawing.

Fig. 1 is a longitudinal sectional view through a cylinder liner of a two-stroke opposed-piston internal combustion engine;

Fig. 2 is an exterior side view of a cylinder liner similar to that of Fig. 1 but including a modification;

Fig. 3 is a sectional 'view taken on the line III-I11 of Fig 1, and

Fig. 4 is an enlarged fragmentary view of a modification.

As shown in Figs. 1, 2 and 3, the cylinder liner 1 which is mounted in the jacket I has an enlarged middle part 2 located at a position midway between the inner dead centers of the pistons 3 and 4. An annular groove 5 is formed in the middle 'part and the heat protective ring 5 is mounted in the groove. The fuel valve 8 is mounted in an appropriate opening in the middle part and is inserted to extend into and through the protective ring, thereby serving to secure the ring in position especially preventing it from moving circumferentially. A starting valve 9 may also be mounted in an appropriate opening in the middle part and inserted through the protective ring. Advantage may also be taken of the starting valve to secure the protective ring in position in a manner similar to that of the fuel valve.- These threaded through the middle part and also into threaded engagement with the protective ring.

As best shown in Figs. 1 and 2, the cylinder liner has annular enlargements I Z and I 3 longitudinally spaced from the middle part and exterior to that position which is swept by the rings of the pistons 3 and 4, and especially when those pistons are at the ends of their strokes, as when they are at inner dead center. In each of the rings I2 and I3, a plurality of relatively small passageways It and iii are formed for the circulation therethrough of a suitable cooling fluid such as water,

for instance flowing from the cooling space 30 to the passageways I4 to the space 3|, to the transi tion ducts I 6 into the space 32 and to the passageways I5 to the cooling space 33. 'I'hese passageways l4 and I5 may be formed by boring holes through the rings and especially at an angle oblique to the longitudinal axis of the liner as shown in Fig. 2, to the end that they maybe 7 brought very close to the inner bearing surface of the cylinder and thereby effect arapid dissipation of heat.

The liner is preferably so formed that the exteriors of the annular rings I2 and I3 may be covered with a close fitting jacket I, and in order to efiect a circulation of the cooling fluid through the passageways I4 and I5, the enlarged middle part 2 is provided with a number of longitudinal exterior transition ducts I8.

As shown in the modification illustrated in Fig. 2, the cooling passages I 4 and I5 may be formed at one angle oblique to the longitudinal axis of the cylinder liner I and an additional set of cooling passages Il may be formed, in either or both rings I2 and I3 at a different angle oblique to the longitudinal axis.

In the modified form of the invention illustrated in Fig. 4, the protective ring 20 is flexible and ,resilient and is held in position in the annular the following analysis, about 18% chromium, 8%

nickel, and 0.5% molybdenum; or a chromiumsteel having about 20% chromium.

Other metals, such as Nichrome, an alloy of nickel and chromium, may he used. j

The improvements oi the invention give the advantages that, in the middle part, which isfnot swept by or contacted with the piston rings, high -tion 01 heat to eflect an intensive cooling.

I claim: 7

1. In a cylinder liner for a two-stroke opposedpiston internal combustion engine fitted in a jacket having a middle part or said liner which is not swept by the rings on the pistons, the improvement which comprises a heat-protective ring mounted in the interior the middle part, and means for cooling a part or the liner on each side oi!- the middle part which is swept by the piston rings.

2. In a cylinder liner for a two-stroke opposedpiston internal combustion engine fitted in a jacket having a, middle part of said liner which is not swept by the rings on the pistons, the improvement which comprises an annular interior groove in the middle part, an annular heat-protective ring mounted in the groove, means for secm'ing the ring in position, and passage means in the cylinder zones at each side of the middle part and exterior oi the part swept by the piston rings oi. each piston tor the circulation therethrough of a cooling fluid to effect a rapid cooling in those parts of the liner.

3. A cylinder liner according to claim 1 which comprises a heat-protective ring formed of a heat resisting alloy.

4. A cylinder liner according to claim 1 which tudinal axis ofv the liner.

comprises a fuel valve mounted in the liner, and

means connected to the fuel valve to secure the heat-protective ring in position.

5. A cylinder liner according to claim 1 which 6. In a cylinder liner fora two-stroke opposedpiston internal .combustion engine having a middle part which is not swept by the rings on the pistons, the improvement which cmnprises a relatively thick part or the liner which is not swept by the rings on the pistons and which is midway between the inner dead centers of the pistons, an annular groove in the middle part, a heat-protective ring formed or heat resistant metal mounted in the annular groove, means for securing the ring in position, a separate annular enlargement on the liner on each side of and longitudinally spaced from the middle part, said enlargements being exterior or that part or the liner swept by the rings on the pistons when at inner dead center, and a plurality of passageways in each annular enlargement for the circulation therein oi a cooling fluid. 7. A cylinder liner according to claim 6 which comprises passageways bored through said enlargement at such angles that they approach very closely to the inner bearing surface or the cylinder liner which is swept by the piston rings.

- HANS LIEBERHERR.

REFERENCES CITED The following references are of record in the tile of this patent;

UNITED STATES PATENTS Number Name Date 958,905 Bryen May 24, 1910 1,819,759 Valetta Aug. 18, 1931 1,930,186 Witkiewicz et a1. Oct. 17, 1933 FOREIGN PATENTS Number Country Date 177,885 England Apr. 10, 1922 409,579 England May 3, 1934 193,724

Switzerland Jan. 17, 1938

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