WO2009015726A1 - Reciprocating piston machine - Google Patents

Abstract

The invention relates to a reciprocating piston machine having at least one piston (1) cooperating with a valve arrangement (21), comprising a clearance volume (23) present between the piston (1) and the valve arrangement (21), and comprising a pivot element (13), preferably designed as a pivot ring, that has a variable pivot angle (a) relative to a plane (E) on which the rotational axis (D) of a shaft (7) stands upright, said pivot element being connected to a drive element (9) in a jointed fashion, by way of which the pivot element (13) cooperates with the shaft (7).

Description

 reciprocating engine

description

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

Reciprocating engines of the type discussed here are known. They are used, for example, as a CO ₂ refrigerant compressor, hereinafter referred to as KMV, for regulating the interior temperature in motor vehicles. Such reciprocating engines comprise a pivoting element which has a variable pivot angle with respect to a plane on which the axis of rotation of a shaft of the reciprocating engine is perpendicular. The pivoting element is pivotally connected to at least one driver element, via which the pivoting element also cooperates with the shaft, so that upon rotation of the shaft, the pivotal element also rotates. By regulating the pressure and mass ratios in a drive element receiving the pivot element, the pivot angle of the pivot element can be changed. Such machines also have at least one axially along the shaft arranged piston which is movably mounted in a cylinder bore of the reciprocating piston machine and which cooperates with at least one valve arrangement. The valve arrangement preferably comprises a valve plate and a plurality of inlet and outlet valves. Due to the design of such reciprocating engines remains between the valve assembly and the at least one piston, a so-called dead space, when the piston was far into the cylinder bore - caused by a pivoting movement of the pivoting element - hineinverlagert. The piston can not be moved directly to the valve assembly, so at this but remains at a distance to this. In a displacement of the piston in the cylinder bore remains a residual medium in the dead space, which acts as a kind of memory of the medium to be compressed of the reciprocating piston engine. However, this has a negative effect on the starting behavior and the efficiency of the reciprocating piston engine mentioned here. Due to the damping effect of a large dead space, which acts as a sort of gas storage, a reciprocating engine with a small dead space volume is desirable. However, known reciprocating engines with a small dead space volume have the disadvantage that they give loud noises at large swivel angles, due to vibrations and pulsations.

The object of the invention is therefore to provide a reciprocating engine, which on the one hand has a good starting behavior and good efficiency, on the other hand has acoustically optimized properties at large pivot angles of the pivot member.

To solve this problem, a reciprocating engine with the features of claim 1 is proposed. The reciprocating engine is characterized in that it has a variable dead space volume. This is changed so that on the one hand give good starting characteristics, on the other hand, the noise is minimal at large tilt angles.

A preferred embodiment of the reciprocating engine is characterized in that the dead space volume existing between the piston and the valve arrangement depends on the swivel angle of the swivel element. Due to this configuration of the reciprocating engine changes when a change in the pivoting winkeis the pivot element and the dead space volume, which can thus be optimized in terms of high demands on the reciprocating engine.

Particularly preferred is a reciprocating piston engine, which is distinguished by the fact that the dead space volume becomes larger with increasing pivoting angle of the pivoting element and becomes smaller as the pivoting angle decreases. This ensures that at large swivel angles a larger dead space volume is present, resulting in a reduction in noise of the reciprocating engine when operating with large swivel angles. On the other hand, the reciprocating engine at small pivoting angles on a small dead space volume, so that very good starting characteristics and a good efficiency of the reciprocating engine can be guaranteed.

Furthermore, a reciprocating engine is preferred, which is characterized in that the pivot member and the driver element are aligned relative to each other so that at large pivot angles of the pivot member, the distance between a point of the driver element and the intersection of the central axis of the piston with the working surface of the pivot member is smaller as with small swivel angles. The advantageous change in the distance between the point of engagement of the driver element and the intersection of the center axis of the piston with the working surface of the pivot element described here also changes the maximum penetration depth of the piston into the cylinder bore, so that the dead space volume can be regulated in dependence on the pivot angle , Also preferred is a reciprocating engine, in which the point of application of the driver element is arranged in such a distance from the shaft in the bore of the pivot member that it is located in the radial direction outside the central axis of the piston. In particular, it can be provided that, viewed in the radial direction, the point of engagement of the driver element protrudes beyond the center axis of the piston. By means of this particular configuration it is achieved that, when the pivot angle of the pivot element changes, the distance between the point of engagement of the driver element and the intersection of the center axis of the piston with the working surface of the pivot element and thus the maximum piston penetration depth into the cylinder bore can be varied.

Finally, a reciprocating engine is preferred, which is characterized in that a bore in the pivoting member has at least one portion which is arranged at an angle to a plane in which the pivoting element lies. The addressed here section is arranged in the region of the bore, in which the point of application of the driver element is arranged. Here, upon pivoting of the swivel element about the driver element, ie upon a change in the swivel angle, a change in the above-described distance between the point of engagement of the driver element and the intersection of the central axis of the piston with the working surface of the swivel element takes place. It can be provided in particular that the driver element has a first surface and the pivot member has a cooperating with the first surface second surface and these surfaces together form a wedge gear. The invention will be explained in more detail below with reference to the drawing. Show it:

Figure 1 is a sectional view of an assembly of a reciprocating piston engine according to the prior art;

Figure 2 is a sectional view of an assembly of a reciprocating engine according to a first embodiment of the present invention, and

3 is a simplified sectional view of an assembly of a reciprocating engine according to a second embodiment of the present invention.

Figure 1 shows a sectional view of an assembly of a reciprocating piston engine according to the prior art. The reciprocating engine has at least one piston 1, which is movably mounted in a cylinder bore 3 introduced into the reciprocating piston along a central axis M of the piston 1. The central axis M of the piston 1 extends concentrically to the central axis of the cylinder bore 3. On the piston 1, a piston bridge 5 is provided, which causes the oscillating movement of the piston 1. The assembly shown in FIG. 1 is arranged in a so-called drive chamber of the reciprocating piston engine (not shown here).

Also visible from Figure 1 is a shaft 7, for example, with a drive shaft of an internal combustion engine of a motor vehicle, not shown, cooperates, not shown here. On the shaft 7, a driver element 9 is provided which rotates together with the shaft 7 about a rotation axis D. The driver element 9 is mounted in a bore 11 of a pivoting element 13 and has a driver head 15, which is here exemplified spherical and around which the pivot member 13 is articulated. The pivoting element 13 is here exemplified as a pivot ring, but also conceivable is the design as a swivel or swash plate. The pivoting element 13 is arranged between the sliding shoes 17 and 17 'below the piston bridge 5, so that the pivoting element 13 can thus rotate underneath it and thereby causes a displacement of the piston 1 via the piston bridge 5, wherein the sliding shoes 17 and 17' pivot within the Enable piston bridge 5 and protect the pivot member 13 from wear.

The pivoting element 13 is, as can not be seen in FIG. 1, fastened by means of pins arranged in bearing sleeves, which extend perpendicular to the image plane of FIG. 1, to a guide body, which is preferably designed as a guide sleeve. The guide body is axially displaceably mounted on the shaft 7 and thus allows the pivoting of the pivot member 13 by a pivot angle α relative to a plane E ₁ on which the axis of rotation D of the shaft 7 is perpendicular. The pivoting angle α of the pivoting element 13 can be adjusted via pressure and mass forces in the drive chamber of the reciprocating engine. The greater the swivel angle α, the greater the maximum stroke of the piston 1 and thus the delivery mass flow of the reciprocating engine.

The start of the reciprocating engine takes place in a starting position of the pivoting element 13, not shown here, wherein this is pivoted α with respect to the plane E at a small pivot angle. Depending on the desired mass output of the Hubkol- benmaschine the pivot angle α of the pivot member 13 is set larger, so that the piston 1 further displaced out of the cylinder bore 3, the stroke of the piston 1 is thus increased to suck in more mass flow, compress and eject again.

The operation of a reciprocating engine is otherwise well known, so it will not be discussed further here.

If during a rotation of the pivoting element 13 the driving head 15 is located in the region of the piston bridge 5, in particular if a point of application 19 of the driving element 9 lies on the center axis M of the piston 1, the piston 1 assumes a position in which it reaches a maximum is pushed far to the right in the cylinder bore 3, so its stroke is minimal. This arrangement defines a certain distance of the piston 1 to the valve arrangement 21 and thus a certain dead space volume. FIG. 1 makes it clear that in this case there is a dead space of width b between the end of the piston 1 facing away from the piston bridge 5 and a valve arrangement 21 only indicated here, which defines a dead space volume 23. Ideally, the reciprocating engine is designed for this position of the piston 1, so that the smallest possible dead space results.

When starting the reciprocating engine, so if the pivot member 13 is arranged at a small pivot angle α to the plane E, a small dead space volume 23 is necessary to ensure optimum starting behavior of the reciprocating engine. In known from the prior art reciprocating engines that is Dead space volume 23 constant, so that a small dead space volume 23 at large swivel angles α, or at high piston stroke, to noise, in particular caused by vibration noise of the reciprocating engine leads. The dead space volume 23 there depends only on the dead space size specified by the manufacturer.

FIG. 1 makes it clear that with an increasing pivoting angle α of the pivoting element 13, the distance r of the radially outer end of the pivoting element 13 decreases towards the axis of rotation D of the shaft 7, so that pivoting and displacement of the pivoting element 13 about the driving head 15 of the driving element 9 takes place. In the known reciprocating piston engine shown in FIG. 1, the dead space volume 23 remains constant at all swivel angles α of the swivel element 13. This is due to the fact that the minimum stroke of the piston 1 is always the same, so that the piston can always be displaced equally far into the cylinder bore 3, independently of the swivel angle α, when the driver head 15 is in the region of the piston bridge 5.

Figure 2 shows a sectional view of an assembly of a Hubkol- benmaschine according to a first embodiment of the present invention. The same parts are provided with the same reference numerals, so that reference is made to the description of Figure 1.

Shown again in FIG. 2 are the driver head 15 arranged in the pivoting element 13 and that fastened to the shaft 7

Carrier element 9. In the embodiment shown here, the bore 11 in the pivot member 13 has a portion 25th on, in which the engagement point 19 of the driver element 9 is arranged and which is designed such that it is arranged at an angle ß to a plane B, in which the pivoting element 13 is located.

The driver element 9 or its driver head 15 has a first surface 27 and the pivot element 13 has a second surface 29 which interacts with the first surface 27 as a kind of sliding / rolling bearing.

From Figure 1 it can be seen that the two surfaces 27 and 29 form a wedge gear. When the pivot element 13 is pivoted about the driver head 15 or when the distance r changes, the wedge mechanism causes the distance between the point of application 19 of the driver element 9 and an intersection point S of the center axis M of the piston 1 with a working surface 31 of the pivot element 13 changed.

If the pivoting element 13, for example, pivoted from the position shown in Figure 2 to a smaller pivot angle α to the plane E counterclockwise, the distance r is larger, the wedge formed by the configuration of the bore 11 between the point of application 19 and pushes Working surface 31 so that the distance between the intersection S and the point 19 of the driver element 9 is larger.

The point of application 19, whose axial position is predetermined by the attachment of the driver element 9 on the shaft 7, does not change its axial position with a change in the pivot angle α, while the intersection S its axial position on the central axis M of the piston 1 in dependence on the pivot angle α changed. When the distance between the point of intersection S and the point of application 19 increases, the point of intersection S virtually moves on the central axis M to the right in the direction of the valve arrangement 21.

The larger distance between the intersection point S and the driver element 9 also reduces the dead space volume 23, since the piston 1 has a smaller minimum lift by the amount of the increased distance between the point of application 19 and the point of intersection S, that is, be displaced further into the cylinder bore 3 can.

Conversely, if the pressure conditions in the reciprocating piston engine cause the pivoting element 13 to have larger pivoting angles α, ie if the distance r becomes smaller, the portion 25 of the bore 11 also pivots about the driving head 15, with the surface 29 on the surface 27 of the driving head 15 slides along so that the thinner end of the wedge formed by the surfaces 27 and 29 between the intersection point S and the point of application 19 and the distance between them is thus smaller.

The intersection point S according to FIG. 2 thus assumes a further axial position displaced to the left on the central axis M in the direction of the

Attack point 19, as it is the case for smaller pivot angles α. Due to the smaller distance of the minimum stroke of the piston 1 is increased. Its minimum stroke position is assumed by the piston 1 when the driver element 9 is located in the region of the piston bridge 5 during a rotation of the shaft 7.

The maximum penetration depth of the piston 1 into the cylinder bore 3 is reduced by the amount by which the distance between the Intersection S and the point 19 is smaller. The dead space volume 23 is thus larger.

It thus turns out that the wedge gear mechanism causes the distance between the point of intersection S and the point of application 19 of the driver element 9 to diminish at larger pivoting angles α of the pivoting element 13 and the dead space volume 23 is thereby increased, or the width b of the dead space greater becomes.

In the case of smaller pivoting angles α, on the other hand, ie if the distance r increases and thus the wedge gear realized by the surfaces 27 and 29 increases the distance between the point of application 19 of the driver element 9 and the point of intersection S, the piston 1 can also move further into the cylinder bore 3 move in when the driver element 9 is in the region of the piston bridge 5, so that the dead space volume 23 is smaller.

The opposite the plane B inclined portion 25 of the bore of the pivot member 13 is not limited to the embodiment shown here. Rather, numerous other embodiments are conceivable which ensure a variable dead space volume 23, in particular as a function of the swivel angle α of the swivel element 13.

For example, the angle β can be varied in order to realize different changes of the dead space volume 23 with respect to a change in the swivel angle α. However, it is also conceivable to form a multi-stage wedge gear, so provide several sections ß with different angles. It is also conceivable, however, to design the driver head 15 in such a way that a wedge mechanism is realized with an ordinary cylindrical bore in the pivoting element 13, ie that the driver head 15 is not spherical but oval or provided with bevelled surfaces, in other words a wedge mechanism between the driver element 9 and the pivot member 13 to realize.

Figure 3 shows a simplified sectional view of an assembly of a reciprocating engine according to a second embodiment of the present invention. The same parts are provided with the same reference numerals, so that reference is made to the description of the preceding figures. For reasons of simplification, the piston bridge is not shown here, via which the piston 1 is coupled to the pivoting element 13. In this respect, reference is made to Figures 1 and 2.

The embodiment according to FIG. 3 of the present invention has, in contrast to the exemplary embodiment according to FIG. 2, no section which is inclined at an angle to the plane B. The bore in which the driver element 9 is mounted, so it is purely cylindrical.

FIG. 3 makes it clear that the point of application 19 of the driver element 9 is arranged at such a distance R from the axis of rotation D of the shaft 7, not shown here, in the bore 11 of the pivot element 13, that it is viewed in the radial direction outside the central axis M of the piston 1 lies.

Preferably, the engagement point 19 of the driver element 9, as shown in Figure 3, with such a distance R to the Drehach- D se the shaft 7 arranged that it extends in the radial direction seen over the central axis M of the piston 1. The distance R between the axis of rotation D and the point of application 19 of the driver element 9 is thus greater than the distance R ¹ between the axis of rotation D and the center axis M of the piston first

Swings the pivot member 13 in a clockwise direction, so that the pivot angle α increases so and the distance r is smaller, so increases in this embodiment, the distance between the point 19 of the driver head 15 and the intersection S, in which the center axis M of the piston 1 the Working surface 31 of the pivot member 13 intersects when the driver element 9 is located in the region of the piston bridge, not shown here. The minimum stroke of the piston 1, so its maximum depth of penetration into the cylinder 3, is thereby smaller and the dead space volume 23 larger.

If the swivel angle α is smaller due to the pressure conditions in the reciprocating piston, the distance r increases and the swiveling element 13 executes a swiveling movement about the swivel head 15, wherein surfaces 27 'and 29' of the driver head 15 and of the Swivel element 13 slide along each other and roll against each other, so there is a rolling / sliding movement instead.

By pivoting counterclockwise, ie in the direction of smaller pivot angle α of the pivot member 13, the distance between the engagement member 19 and the intersection S. increases the intersection point S moves quasi on the central axis M of the piston 1 to the right in the direction of the valve assembly 21st , By increasing the distance between the engagement element 19 and the point of intersection S, however, the maximum penetration depth of the piston 1 into the cylinder bore 3 increases, so that at smaller pivoting angles α the dead space volume 23 becomes smaller.

As has already been described above, the distance between the engagement element 19 and the intersection point S decreases at larger pivot angles α, thereby reducing the maximum penetration depth of the piston 1 into the cylinder bore 3 and thus increasing the dead space volume 23 or the width b of the dead space ,

Due to the advantageous embodiment of a reciprocating engine according to the present invention, it is thus possible in an advantageous manner to realize a variable dead space volume 23 and a variable width b of the dead space. In this case, the dead space volume 23 is dependent on the pivoting angle α of the pivoting element 13, so that α is a large dead space volume 23 is preferably present at large swivel angles and so vibrations, pulsations and airborne sound are attenuated during operation with large swivel angles α by the large dead space volume 23 in an advantageous manner. The acoustic behavior of a reciprocating engine at large swivel angles α is thus significantly improved.

The present invention also makes it possible that with small pivoting angles α of the pivoting element 13 a small dead space volume 23 is present, so that the starting behavior is not impaired. Due to the variable dead space volume 23, the present invention advantageously makes it possible to combine good starting behavior with a small dead space volume 23 and small swivel angles α with the acoustic advantages of a large dead space volume 23 at large swivel angles α.

A dead space volume 23 dependent on the swivel angle α can be realized in various ways. It is crucial that the pivoting element 13 and the driver element 9 are aligned with each other so that the distance between the point 19 of the driver element 9 and an intersection point S of the pivot member 13 changes in a change of the pivot angle α.

For realizing a dead space volume 23 that can be changed over the swivel angle α, it is also conceivable to combine the exemplary embodiments shown here, that is, to provide, for example, a wedge mechanism between the working surface 31 of the swivel element 13 and an offset of the point of application 19 with respect to the central axis M.

LIST OF REFERENCES

I piston

3 cylinder bore

5 piston bridge 7 shaft

9 driver element

I 1 hole

13 pivoting element

15 driving head 17 sliding shoe

17 'shoe

19 point of attack

21 valve arrangement

23 Dead space volume 25 Section

27 first area

27 'first surface 29 second area

29 'second surface

31 work surface

E plane M central axis

D rotation axis α angle ß angle

S intersection R distance

R 'distance b width

B level r distance

Claims

claims 1. Reciprocating piston engine having at least one piston (1) cooperating with a valve arrangement (21), having a dead space volume (23) present between the piston (1) and the valve arrangement (21) and having a pivoting element (13), preferably designed as a pivoting ring. which has a variable swivel angle (α) with respect to a plane (E) on which the axis of rotation (D) of a shaft (7) is perpendicular, and which is articulated to at least one driver element (9) via which the swivel element (13 ) cooperates with the shaft (7), characterized by a variable dead space volume (23). 2. Reciprocating piston engine according to claim 1, characterized in that the dead space volume (23) from the pivot angle (α) of the pivoting element (13) depends. 3. Reciprocating piston engine according to claim 1 or 2, characterized in that the dead space volume (23) with increasing pivot angle (α) of the pivoting element (13) becomes larger. 4. Reciprocating piston engine according to one of the preceding claims, characterized in that the pivoting element (13) and in a bore (11) mounted therein driving element (9) are aligned relative to each other so that at large pivoting angles (α) of the pivoting element (13) the distance between an engagement point (19) of the driver element (9) and the intersection (5) of the central axis (M) of the piston (1) with a working surface (31) of the pivoting element (13) is smaller than at small pivoting angles (α). 5. Reciprocating piston engine according to one of the preceding claims, characterized in that the engagement point (19) of the driver element (9) at such a distance (R) to the shaft (7) in the bore (11) of the pivoting element (13) is arranged, that it is located in the radial direction outside the central axis (M) of the piston (1). 6. Reciprocating piston engine according to claim 5, characterized in that the engagement point (19) of the driver element (9) at such a distance (R) to the shaft (7) in the bore (11) of the pivoting element (13) is arranged, that it extends in the radial direction beyond the central axis (M) of the piston (1). 7. A reciprocating piston engine according to one of the preceding claims, characterized in that a region of the bore (11) in the pivoting element (13), in which the engagement point (19) of the driver element (9) is arranged, at least one portion (25) has, which is arranged at an angle (ß) to a plane (B), in which the pivoting element (13) is located. 8. A reciprocating engine according to claim 7, characterized in that the driver element (9) has a first surface (27) and the pivot element (13) cooperating with the first surface (27) second surface (29), and in that these surfaces (27 , 29) form a wedge gear acting on the distance between the point (19) of the driver element (9) and the intersection (S) of the central axis (M) of the piston (1) with the working surface (31) of the pivot element (13) ,