US1405887A - Piston for internal-combustion engines - Google Patents

Description

0. ALT.

PISTON FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED NOV. 25, 1921.

1 ,405,8 87 Patented Feb. 7, 1922.

jvemian UNITED STATES PATENT OFFICE.

OTTO ALT, OF KIEL, GERMANY, ASSIGNOR TO FRIED. KRUI'P AITIENGESELLSOHAFT, GERMANIAWERFT, OF KIEL-GAARDEN, GERMANY.

PISTON FOR INTERNAL-COMBUSTION ENGINES.

Application filed November 25, 1921.

To all whom it may concern:

Be it known that I, Or'ro ALT, residing at Kiel, Germany, a citizen of the German Republic, have invented a certain new and useful Improvement in Pistons for Internal-Combustion Engines, (for which I have filed application for patent in German Nov. 22, 1920, under Serial No. K 25,304, 46 C.) of which the following is a specification.

This invention relates to istons for internal combustion engines of the kind in which there is inserted in the piston bottom a mushroom-shaped protecting body intended to protect the bottom surface facing the combustion chamber of the cylinder, against the destructive action of the thin flames arising at the nozzles of the fuel-injecting valves.

The object of the present invention is to produce a piston of the kind described which, even if made with large dimensions, has a high durability and works satisfactorily even without being cooled by water and which can be repaired in an easy and convenient way if damaged.

According to the invention, this object is chiefly attained by the fact that the surface, facing the combustion chamber, of the mushroom-shaped protecting body, is entirely or partially covered by aspecial discshaped protecting plate consisting of a material which offers a particularly great resistance against high temperatures, said protecting plate being connected to the protecting body merely on its centre or in the vicinity thereof, and the outer edge of which has lateral clearance so that the plate can freely expand in all directions and, after removing the cylinder cover, may be easily replaced from the piston bottom side.

An embodiment of the subject-matter of the invention is shown by way of'example in the accompanying drawing which shows, in section, a piston of a single-acting internal combustion engine with oscillating piston rod.

The piston body A is constructed so as to form, at its end facing the combustion chamber of the cylinder, an annular hollow body a the interior a, of which is intended to receive in the known manner, a cooling liquid. In a central recess of the hollow body a there is inserted a mushroom-shaped protecting body B which covers the greater portion of the front surface of the body a Specification of Letters Patent.

Patented Feb. 7,1922.

Serial No. 517,758.

and the extension 6' of which is connected, in the manner illustrated, to the piston body A by screw bolts. Between the outer edge 6 of the protecting body B and the piston body as well as between the latter and the extension 6 there is provided lateral clearance so that the body B is capable of expanding freely relatively to the piston body A, even with very high temperatures.

In order to prevent erosions at the points where the thin flames ejected at the fuel nozzles strike the projecting body B which is usually made of the same or similar material as the piston A, the body B is covered by a special disc-shaped protecting plate C which consists of a material offering a particularly strong resistance against being destroyed by high temperatures. This protecting plate has on its lower side a tap-shaped screwthreaded projection c by means of which it is screwed into the protecting body B from above. As the rotecting body B and the protecting plate 8 are thus rigidly con,- nected to each other in their centres only and, moreover, -a lateral clearance exists between the edge of the plate C and the body B, the plate C is capable of expanding freely in all directions. Any unintentional unscrewingofthe plate C out of the body B during the working of the engine is pre vented by a safety screw D.

In place of the tap-shaped screw-threaded projection 0, which is made in one piece with the protecting plate C, a separate screw bolt may obviously be provided havin .a sunk-in head covered by material resistlng to high temperatures. Further, instead of a single screw bolt a plurality of bolts may be'used which must, however, be located in the immediate vicinity of the centre of the projecting plate in order to allow the latter to freely expand.

Preferably the radius of curvature 1" of the upper cavity of the protecting plate C is smaller than the radius of curvature R of the cavity of the body B surrounding the plate C. This arrangement offers the advantage that the thin flames striking the protecting plateC flow away in lateral direction without directly contacting the protecting body B, as indicated by the arrows in the drawlngs, so that the durability of the body B is extraordinarily increased.

Whereas the protecting plate constructed in accordance with the invention is able to of a heat-protecting body freely expand in all directions so that no warping of the plate and destroying of the same, resulting therefrom, can take place, and whereas the described construction makes it possible to easil replace the protecting plate if damage owing to unforseen circumstances, the invention forms a means for producing larger pistons than hitherto could be made, without a watercooling arrangement. It is to be noted, however, that the invention can be employed both in water-cooled pistons and in pistons not cooled by water.

Claims.

1. In a piston for internal combustion engines the combination with the piston body, connected to said piston body at the combustion chamber side, and a second protecting body consisting of highly heat-resisting material and covering the portion of said first-named protecting body which is most exposed to heat.

2. In a piston for internal combustion engines the combination with the piston body, of a heat-protecting body connected to said piston-body at the combustion chamber side, and a disc-shaped second protecting body consisting of highly heat-resisting material and covering the portion of said first-named protecting body which is most exposed to heat, clearance being provided between said first-named protecting body and said second protecting body to enable free expansion of the latter.

3. In a piston for internal combustion engines the combination with the piston body, of a heat-protecting body connected to said piston body at the combustion chamber side, and a disc-shaped second protecting body consisting of highly heat-resisting material and covering the portion of said first-named protecting body which is most exposed to heat, and connected to the first-named protecting body near to its centre, clearance being provided between said first-named protecting body and said second protecting body to enable free expansion of the latter.

4. In a piston for internal combustion engines the combination with the piston body, of a heat-protecting body connected to said piston body at the combustion chamber side and having a concave protecting surface, a disc-shaped second protecting body consisting of highly heat-resisting material and covering the portion of said first-named protecting body which is most exposed to heat, and having likewise a concave protecting surface the radius of curvature of which is smaller than that of the protecting surface of the first-named protecting body.

5. In a piston for internal combustion engines the combination with a piston body, of a heat-protecting body connected to said piston body at the combustion chamber side, and having a concave protecting surface, a disc-shaped second protecting body consisting of highly heat-resisting material and coverin the portion of said first-named protecting ody which is most exposed to heat, and having a' concave protecting surface, the radius of curvature of which is smaller than that of the protecting surface of said first-named protecting body, these two protecting bodies being connected to each other in the vicinity of their centres, clearance bein provided between said two bodies to enab e free expansion of said second bod The foregoing specification signed at iel,

Germany, this 19th day of October, 1921.

I o'r'ro ALT.

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