DE3310497A1 - Reciprocating piston engine - Google Patents

Abstract

In the case of a reciprocating piston engine, a cylinder head gasket (30) is arranged between cylinder head (6) and cylinder liner collar (21), which gasket comprises an axially deformable metal washer (31) and a flanged plate (33) largely enveloping this. In order to achieve correct centring of the gasket (30) without the risk of destroying it, the gasket (30) has a plurality of lugs which bear on at least one of the surfaces (24 and 25), which define a gap (27) between cylinder liner collar (21) and the corresponding recess (22) in the crank casing (1). The lugs preferably bear on both surfaces (24, 25) whilst centring the cylinder liner (2) in the crank casing (1). <IMAGE>

Description

Reciprocating engine

The invention relates to a reciprocating engine according to the preamble of Claim 1.

In the case of reciprocating piston engines with wet cylinder liners, the seal is used between the crankcase and cylinder liner on the one hand and for sealing between The cylinder liner and cylinder head, on the other hand, are in many cases a surface seal intended. This must be a gas seal between the liner collar and the cylinder head as well as a seal for the coolant and lubricating oil transfers cause between crankcase and cylinder head.

For more heavily loaded reciprocating piston engines, especially diesel engines with higher ignition pressures, a seal is used instead of a simple surface seal provided, which consists of a single or multi-layer carrier plate that is attached to the liner collar, at liquid crossings and at openings for cylinder head bolts mounts the end having metallic or elastomeric materials. Such seals can like the above-mentioned surface gasket easily over the cylinder head screws or separately provided locating pins or

sleeves are centered.

In order to meet even higher requirements, larger or particularly highly stressed reciprocating piston engines separate seals for the Combustion chamber on the one hand and the liquid transfers on the other hand provided. Of the The combustion chamber is created by a metallic ring between the liner collar and Cylinder head sealed, while the liquid transfers through O-rings be sealed from elastomers.

In particular if the motor causes relative movements due to frequent load changes are to be expected on the combustion chamber seal, the seal in the generic Way executed. This seal is centered with a certain amount of play on the radially outer side of the fire protection collar of the cylinder liner at.

During assembly, such a seal inevitably comes with yours Inner edge for contact with the radially outer edge of the fire protection collar. At the Tightening the cylinder head bolts will reduce the inside diameter of the gasket due to their compression.

If the seal has already been in contact with the fire protection collar, it can no longer expand here, with the result that the inner edge deformed the seal. In the case of high loads, such as the high power output of the engine and the associated increase in ignition pressure occur, it can break the seal and thus lead to failure of the seal in the long term.

The invention is therefore based on the object of a reciprocating piston engine of the generic type to be designed so that failure of the seals is effective is avoided.

According to the invention, this object is achieved by the characterizing features of claim 1 solved. The seal is reliably centered by these tabs, these tabs on the outer surface of the liner collar and / or on the associated Make contact with the inner surface of the recess of the crankcase. This can be a sufficient radial distance between the seal and the fire protection collar must be maintained. The one-piece design of the seal and flap according to claim 4 leads to that no possibly disturbing weld seams or the like. Are present.

The. An embodiment according to claim 5 has the consequence that the tabs are precisely match the shape of the gap, so it can also be easily inserted during assembly are. On the other hand, the embodiment according to claim 6 leads to a production engineering Simplification and also so that the flaps tighten better. At the level Embodiment according to claim 6, it is useful if the supplementary measures according to claim 7 are provided.

Claim 8 indicates the optimal distribution of the flaps.

The further embodiment according to claim 9 is particularly flat formed flap according to claim 6 of advantage, so that the flap before assembly do not protrude too far from the shape of the gap.

In the embodiment according to claim lo, in particular with the tab can be realized according to claim 6, the tabs also take over the centering at the same time the Liner in the crankcase in the one adjacent to the cylinder head Area. This has the consequence that on the otherwise necessary centering of the cylinder liner on the side of the liner collar facing away from the cylinder head can be dispensed with can. This in turn has the consequence that the area through which the cooling water flows is still closer to the cylinder head, so that in the area of the largest Better cooling is possible in the event of heat. In addition, the top one can also Piston ring of the piston are arranged closer to the combustion chamber. This will make that Reduced gas volume due to the top land clearance between the top piston ring and piston crown is unavoidable.

The reduction of this gas volume leads to an improvement in the Performance, fuel consumption and pollutant emissions - a realization the lower top land height, which is desirable per se, has so far essentially failed because the top piston ring is not above the top dead center Cooling water jacket should be located in order to avoid impermissibly high temperatures at the critical Point of movement reversal to avoid. By moving the piston rings in the direction of the upper edge of the piston there is also an extension of the piston skirt and thus improved piston guidance in the cylinder. For a good mastery the gas passage and the oil consumption at the piston is in itself a larger (radial) Play at the top land is an advantage; however, its realization failed because of the negative Effects on the performance and emission data as a result of the enlarged dead space between the top piston ring, cylinder liner, top land wall and top edge of the piston. Thereby the top land height can be reduced by the measures according to claim can, the top land spar 1 can be enlarged without deterioration.

Further advantages and features of the invention emerge from the description of an embodiment based on the drawing. 1 shows a section by a reciprocating engine In the area of the cylinder in a plane of the cylinder axis transversely to the crankshaft, FIG. 2 shows a partial section from FIG. 1 corresponding to the section delimitation II in FIGS. 1 and 3 show an embodiment that is modified compared to FIGS. 1 and 2.

As can be seen from the illustration in FIG. 1, a reciprocating piston engine a crankcase 1 in which a cylinder liner 2 is arranged. These is on the side facing the crankcase 3 in a snug fit 4 of the crankcase 1 held centered and also sealed by means of seals 5. On her other the cylinder head 6 adjacent end it is by means of a radially projecting Centering collar 7 with slight play (of about 0.1 mm) in the corresponding hole of the crankcase 1 centered. Between the snug fit 4 and the centering collar 7 is a cooling jacket 8 surrounding the cylinder liner 2 is formed. This cooling jacket 8 is supplied above the snug fit 4 coolant on the opposite Page is discharged through a coolant channel 9 to the cylinder head 6. The transition of the coolant channel 9 between cylinder head 6 and crankcase 1 is by means of a Sealing ring made of elastomer or the like. Sealed.

A piston 11 is slidably arranged in the cylinder liner 2, who in the usual way via a Connecting rod 12 with a crankshaft 13 is connected.

In the piston head 14, a combustion bowl 15 is formed into which by means of an injection nozzle 16 fuel is injected. Otherwise is the combustion chamber 17 between the piston head 14, the cylinder head 6 and the respectively assigned Area of the inner wall 18 of the cylinder liner 2 is limited. The reciprocating piston 11 is in the usual way provided with piston rings, the area between the piston crown 14 and the uppermost piston ring 19 closest to it is referred to as the top land 20 will. The distance h between the piston bottom 14 and the adjacent piston ring 19 is the top land height. The radial distance between the inner wall 18 of the cylinder liner 2 and the top land 20 is the top land game.

The cylinder liner is on the side facing the cylinder head 6 2 is provided with a liner collar 21, which is connected to a corresponding recess 22 of the crankcase 1 and axially on a radial surface 23 of the recess 22 - in the tensioned state - rests watertight. Between the outer surface 24 of the Liner collar 21 and the corresponding inner surface 25 of the recess 22 is a gap 27 extending concentrically to the cylinder axis 26 is formed.

The liner collar 21 has in its interior, so the combustion chamber 17 adjacent, area has a fire protection collar 28 that has little play to the cylinder head 6. The area adjoining it radially outwards points an annular disk-shaped recess 29 open towards the gap 27. In this Recess 29 is a cylinder head gasket 30 is arranged against a gas outlet from the combustion chamber 17 seals. This seal 30 has a particular made of steel on a metal ring disk 31, which is connected to a cylinder head 6 protruding bead 32 is provided. This metal washer 31 is of a Flanged plate 33, also preferably made of steel, surrounded, which has approximately the shape of a lying U has. This flanged plate 33 wraps the washer 31 on the liner collar 21 and the cylinder head 6 and the fire protection collar 28 facing sides. As particularly evident from Fig. 2, the seal 30 can be based on the described Design are elastically deformed in the direction of the cylinder axis 26, so that always with corresponding tension between cylinder head 6 and crankcase 1 a proper seal between cylinder head 6 and cylinder liner 2 is guaranteed is.

Several tabs 34 are bent perpendicularly from the flanged plate 33, which protrude into the gap 27 and either - as shown in Fig. 2 - at the Outer surface 24 of liner collar 21 or else on inner surface 25 of the recess 22 are in contact. By this measure, the seal 30 is relative to Liner collar 21 centered so that between the fire protection collar 28 and the seal 30 a sufficient distance a can be maintained that a contact between the fire protection collar 28 and the seal 30 makes impossible. The tabs 34 can be adapted to the annular cylindrical shape of the gap 27; but they can also be trained be. In the latter case in particular, they are tapered downwards, in the form of a U or a triangle or a trapezoid.

In the modified embodiment of FIG. 3 are in the Usually three tabs 34 firmly attached to the inner surface 25 of the recess 22 and the outer surface 24 of the liner collar 21 with the result that this results in the centering of the Cylinder liner 2 is already effected in the area of the cylinder head 6. The at the embodiment according to FIGS. 1 and 2 provided the liner collar 21 adjacent Centering collar 7 can therefore be omitted, so that the cooling jacket 8 'is immediately up to the liner collar 21 can be brought up. The coolant channel 9 is accordingly also introduced immediately adjacent to this. As a result, the The top land height h can be reduced considerably compared to the top land height h.

Although the cylinder head gasket 30 is always made of a metal washer 31 and flange plate 33 is described consisting of, it can be used in simple applications also merely consist of a metal ring disk on which the tabs 34 are trained directly.

It is also possible that the crankcase 1 up to the radial Surface 23 is reduced so that the recess 22 is omitted. In this case it is of course, only a contact of the tabs 34 on the outer surface 24 of the liner collar 21 possible. A centering of the cylinder liner 2 by means of the tabs 34 and the resulting advantages explained in connection with FIG. 3 are naturally not possible here.

If the bead 32 is still shown in FIGS. 2 and 3, so-this is for illustrative purposes only.

When bracing the cylinder head 6 against the Crankcase 1 this bead 32 is naturally pressed flat, whereby the radially inner Area of the metal ring disk 31 or the flanged plate 33 with a reduction in size of the distance a comes closer to the fire protection collar 28.

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Claims (9)

Requirements reciprocating piston engine, especially diesel engine with high ignition pressure, with a crankcase, with at least one cylinder head and with at least one wet cylinder liner, with a reciprocating piston slidable in each cylinder liner is arranged, one from the cylinder head, from the cylinder liner and from the reciprocating piston delimited combustion chamber is provided, the cylinder liner by means of a Liner collar is axially fixed in the area of the top of the crankcase, and wherein the cylinder head-side surface of the liner collar in that of the combustion chamber adjacent area a fire protection collar and in the area adjacent to the gap has a radially outwardly open recess in which one on the cylinder head and The cylinder head gasket is arranged on the liner collar and consists of a axially deformable metal washer and, if necessary, a flanged plate that largely envelops it the end Consists of metal, characterized in that the seal (30) is provided with several tabs (34) which the outer surface (24) of the liner collar (21) reach over and fix the seal (30) radially. 2. Motor according to claim 1, wherein the Laufbüchsenbuiid under release an annular cylindrical gap arranged in a recess of the crankcase is, characterized in that the tabs (34) on at least one of the gap (27) delimiting surfaces (outer surface 24 of the liner collar 21 or inner surface 25 of the recess 22) is applied. 3. Engine according to claim 1 or 2, wherein the cylinder head gasket is a the metal ring disk has a largely enveloping flanged plate, characterized in that that the flange plate (33) is provided with the tabs (34). 4. Motor according to claim 1, characterized in that the tabs (34) are bent at right angles from the seal (30). 5. Motor according to one of claims 1 to 4, characterized in that that the tabs (34) according to the shape of the liner collar (21) in the shape of an annular cylinder section are trained. 6. Motor according to one of claims 1 to 4, characterized in that that the tabs (34) are flat. 7. Motor according to one of claims 1 to 6, in particular according to claim 6, characterized in that the lobes (34) to their free the ends of the seal (30) tapering away. 8. Motor according to one of claims 1 to 7, characterized in that that three tabs (34) are provided at an angular distance of about 120 ° from one another are. 9. Motor according to one of claims 1 to 8, in particular according to claim 6, characterized in that the tabs (34) each extend over an angular range range from about 5 to 70. lo. Motor according to one of claims 1 to 9, in particular according to Claims 2 and 6, characterized in that the tabs (34) each firmly two surfaces delimiting the gap (27) (inner surface 25 of the recess 22 and Outer surface 24 of the liner collar 21) rest.