US2168131A - Internal combustion engine - Google Patents

Description

Aug. 1, 1939. O MADER 2,168,131

INTERNAL coMBusTIbN ENGINE? Filed July 22, 1937 2 Sheets-Sheet].

g- 1, 1939- i o. MADER 2,168,131

INTERNAL COMBUSTION ENGINE I Filed July 22, 1957 2 Sheets-Sheet 2 Patented Aug. ,1, 1939 UNITED STATES PATENT OFFICE INTERNAL COMBUSTION ENGINE Application July 22, 1937, Serial No. 155,013 In Germany August 3, 1936 7 Claims.

My invention relates to internal combustion engines. It has' particular reference to liquidcooled engines having a cylinder barrel or liner mounted in the cooling jacket, the end of. the

liner being pressed onto its seat in the cylinder cover, as disclosed for instance in my copending application for Letters Patent of the United States, Serial No.- 16,415, filed April 15, 1935, now Patent No. 2,l27,825,.August 23, 1938. In the construction disclosed in my copending application the end of the liner contacts with the cover in a plane, annular surface. In the operation of these engines it has been found that, even if the contact surfaces were machined with great care, leakage at this point could not be avoided with absolute certainty. Investigations have shown that this is due to the fact that the jacket and the cover which, in order to save weight, are formed with comparatively thin walls subjected to highmechanicalstresses (gas pressure, sliding pressure of the piston, turning moment reactions transmitted by the engine casing) and heat stresses (arising from differences in the temperature of the wall of the combustion chamher, irregularities in heat elongation brought about by valve sockets etc.) suffer temporary and permanent irregular changes of shape. In consequence of these changes and eventually also of unavoidable inaccuracies in the production of. the parts it may happen that the plane packing surfaces of the liner and its seat on the cylinder body or cover do not extend in parallel, but en-.

close between them a small angle, so that at one side of the cylinder a gap will be formed between the end of the liner and the seat, or at least the force with which the parts are pressed against each other, may become so low as not to suillce for effecting a reliable packing.- The leak which may form under these circumstances cannot be rid of by pressing the liner onto its seat with great force.

I avoid this drawback according to this invention by forming the packing surface approximately as a spherical surface, the center point '45 of which lies on the cylinder axis below the joint between the liner and the cover, and preferably within the cylinder. Since, owing to the low wall thickness of the liner, the packing surface is only 0 very .narrow, its spherical form may also be replaced by a conical surface, the angle of the cone being so chosen that the surface contacts with the spherical surface in the packing line.

In the drawings ailixed to this speciflcationand forming part thereof several devices embodying (Cl. 123-173) I my invention are shown diagrammatically by way of example.

In the drawings Fig. 1 is an axial section of part of a cylinder jacket, liner and cover, as shown in my copending 5 application afore-menti oned,

Fig. 2 showing in detail, drawn to a larger scale, the packing formed at the liner seat in the cylinder cover.

Fig. 3 is a diagram of forces.

Fig. 4 is a view similar to Fig. 1, in which the action of a packing according to this invention is illustrated on an exaggerated scale.

Figs 5 and 6 are axial sections, drawn to a larger scale, illustrating two modified forms of 15 packlngs.

Referring to the drawings and first to Fig. 1, I is the cylinder packet, 2 is the cover mounted thereon, l is the liner and 5 is the inner wall of thecover offering a seat 6 for the end of the 20 liner. The contact surfaces of the seat and the liner are parts of parallel cone frusta. The apex 25 of the frustum 6 of the seat lies on the cylin- 'der axis on the side facing the packing. A straight line extending at right angles to the 25 surface 6 and through the middle point of its cross section (point 25) intersects the cylinder axis at a distance a from the surface 6 in the point 21 below the packing. The conical surface of the seat 6 corresponds approximately to a 30 spherical surface with a radius equal to a and the center point at 21. Between the end of the liner and the seat 6 is inserted a thin metal packing ring I. The elastic pressure effecting the packing is supplied, similarly as according to my Patent 35 No. 2,127,825, by longcomparatively thin screw bolts l2, one end of which is fixed in projections [3 formed on the liner 4 and spaced considerably from the packing, while their other end grips the cylinder cover 2 from the outside. The liner is 40 secured in position in the jacket, and the sliding pressure exerted by the piston (forces 11 in Fig.

' 3) is taken up at the inner end of the liner by an inwardly projecting flange ill of the cylinder jacket I, against which abuts an annular projection 9 on the liner, which is formed with a groove in which is inserted a packing ring 8. At the other end the cylinder liner is merely held in place by the conical surface 6, since here the liner must'be capable of a certain adjustment in radial direction. The side pressure acting on the liner has the tendency of displacing the liner along the inclined surface. This tendency is counteracted by the force acting in axial direction and permanently pressing the liner onto its created by the wedge 'action of the inclined packing surface, of the part D, taken up by the packing surface, of the sliding pressures d transmitted on to the liner 4 by the piston. Fig. 3 illustrates the side pressure D as subdivided into the component D2 acting at right angles to the inclined surface 6 and the axial component D1.

Around the surface 6 or at the end of the liner narrow axial projections .l'l (Figs. 1 and 2) may further be provided which, however, do not serve for laterally fixing the liner in position,

' but allow it some play in radial direction. They serve first of all the purpose of facilitating the mounting in place of the packing ring I when assembling the 'parts and of somewhat guiding the liner when mounting it in the cylinder. They go may further serve for preventing the packing from giving way laterally during operation.

Fig. 4 illustrates in an exaggerated manner the action of such packing. In order to more clearly bring out this efiect the surface I 8 on the cylinder 5 body is made wider than it is inreality and is shown as a spherical, surface, the correct position of which is indicated by the dash line ii. The center point of the spherical surface lies on the cylinder axis at 21'. In this correct position of the surface IS the liner assumes its normal position-4' shown in dash lines. Let us assume that the cylinder body has suflered during operation a deformation in consequence of which the spherical surface has changed over from its normal position I 6' to a position l6" extending at an angle thereto and having its center point at 21" so that the abutting surface I6" is shown at a higher level on the right hand side of the figure than on the left hand side. If the liner were to keep it normal position shown in dash lines then, similarly as in the modification shown in Fig. 1, a gap would form on the right hand side, which would give rise to leakage. However, when the liner thus abuts only on one side against the abutting surface, the permanently acting pressure, owing to the wedge action of the inclined abutting surface, generates a transversely directed force at this point, whereby the end of the liner is displaced relative to the abutting surface until it is applied again= onto the surface all over its circumference, so that in spite of the displacement the tight packing between the liner and its seat is maintained. The liner now assumes the position 4", drawn in full lines. In thus changing its position it turns about an axis extending for instance through the point 29. In reality this turning movement is so insignificant as to remain practically unnoticed and to not influence the operation of the engine in any 00 manner. Preferably the conditions are so chosen that the axis 29, about which the liner turns on being adjusted, is located in about the same zone extending transversely to the cylinder axis as the lateral abutment 9, l0 provided at the outer end of the liner, since in this case the abutting surface forms the least hindrance-to a free adjustment of the liner relative to the surface l6.

This is brought out in the drawings by the fact that a point of the liner axis located in the same zone, which in the normal position (4') lies at the point 30', when the liner turns about the axis 29, undergoes substantially only a displacement in the direction of the cylinder axis towards the new position 30/, while the point 29, at which 15 the liner axis intersects the spherical surface i6,

is imparted a lateral displacement towards the point 28" in the spherical surface l4".

This possibility of free adjustment of the liner is guaranteed in the best manner, if, as mentioned above, the center point 21' of the spherical pack- 5 ing surface It or the corresponding point of intersection 21 of the straight line 26-21 extending at right angles to the conical surface 6 with the liner axis lies between the packing I 6 and the abutment 9, I0. 10

The surfaces of the cylinder body and the liner facing each other at the packing place need not both be formed spherically or conically. If a packing ring of corresponding cross section is provided, only one of the two surfaces and the sur- 15 face of the packing ring abutting against it need be spherical or conical.

Fig. 5 illustrates a modified form, in which only the end face of the liner 4 and the abutting surface of the abutting ring 21 are shaped at least 20 approximately according to a spherical surface, while the abutting faces of the cylinder body 5 andthe packing ring 21 are plane surfaces.-

In the modification shown in Fig. 6 the abutting faces of the liner 4 and the packing ring 21 are 25 plane, while the abutting faces of the cylinder body 5 and the packing ring 21 are at least approximately spherical.

I wish it to be understood that I do not desire to be limited to the exact details of construction 39 shown and described for obvious modifications will occur to a person skilled n the art.

I claim:

1. In an internal combustion engine, a cylinder construction comprising an outer case, a cover 35 secured to said case, and a liner within said case, said case and liner forming therebetween a space for cooling fluid, means mounting said liner in said case for tilting movement with respect to the case, and engaging surfaces on said liner and 40 cover for forming a tight joint therebetween in all relative positions of said liner with respect to said cover and case.

2. In an internal combustion engine having a liquid cooled cylinder, a cover for said cylinder, 45 and a liner in said cylinder, means for holding an edge of said liner against said cover, means spaced from said liner edge for tiltingly supporting the side of said liner from the side of said cylinder, and surface means between the edge 0 of said liner and said cover for maintaining a tight joint therebetween throughout movement of the edge with respect to the cover upon tilting of said liner about said supporting means.

3. In an internal combustion engine having a liquid cooled cylinder, a cover for said cylinder, and a liner in said cylinder, means for tiltably holding the surface of an edge of said liner against a surface of said cover, at least one surface havgo ing a spherical contour with the center point thereof located within said liner and below said surface, and packing means between said liner surface and said cover surface.

4. In an internal combustion engine having a as liquid cooled cylinder, a cover, and a liner in said cylinder, said cover and liner having contact surface edges, at least one of said edges having a substantially spherical surface, the center point of which lies within said liner and on the axis 70 thereof, means engaging said surfaces, and means for holding said surfaces in contact with said packing means. 1

5. In an engine as in claim 4, each of said edges having a spherical surface parallel to the surface 1 of the other edge, and said packing means comprising a thin parallel sided metallic ring.

6. In an engine as in claim 4, abutment means for spacing the wall of said liner from the wall of said cylinder, and said holding means comprising bolts secured to said liner at points between said abutment means and said edges and secured to said cover.

'I. In an internal combustion engine having a liquid cooled cylinder, a cover for said cylinder, a liner in said cylinder and seated upon said cover, and bolts secured to said cover and to said liner at points spaced from the seat between said liner and cover, said seat comprising contact surfaces formed as frusta of a cone the apex of which lies above said seat, said surfaces bein thereby substantially spherical in form, the center point of the sphere lying on the longitudinal axis of the liner below said seat, and abutment means for tiltably supporting said liner from the side of said liner below said center point.

OTIOMADER.

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