EP1199452A1 - Internal combustion engine with variable compression ratio and integrated setting actuator - Google Patents

Abstract

Pistons, each having an upper dead center position, are accommodated for reciprocating motion in respective cylinders. The upper dead center position of each piston is altered to vary engine compression ratio by setting drive for turning setting shaft (11) to adjust angular position of eccentric rings (3) to radially shift crankshaft axis (13). The cylinders are arranged in line in engine block. Ring bearings (4) support the eccentric rings in engine block to rotate along the ring axis. Crankshaft bearings (2) support and carry a crankshaft (1) in respective eccentric rings to rotate along the crankshaft axis radially spaced from the ring axis. Connecting rods couple each piston to the crankshaft. A setting arm (8) is secured to and projects from the eccentric rings A toothed component (9) is carried by the setting arm. The setting shaft is rotatably supported on engine block and oriented parallel to the crankshaft. A pinion component (10) has a first pinion, a second pinion, and a resilient connecting unit. The first pinion is secured to the setting shaft and meshes with the toothed component. The second pinion rotates relative to the first pinion, and meshes with the toothed component. The connecting unit couples the first and second pinions, and resists the relative rotation of the pinions. A resilient torque biases the pinions toward each other.

Description

In normal reciprocating piston engines, the position of the piston is in the cylinder only from the position of the crankshaft dependent. Depending on the operation, the compression ratio To be able to change, you have an opportunity to change created in that the connecting rod in two connecting rod parts that is divided by a central joint with each other are connected, and wherein a link arm is articulated on the connecting rod is, the other end of which is on the machine housing slidable articulation point is attached. such Constructions are known from, for example DE-A-29 35 073, DE-A-29 35 977, DE-A-30 30 615 and DE-A-37 15 391. In these constructions, the handlebar arm directly coupled to the middle joint, so that here considerable constructive and operational problems arise. The middle joint builds very wide and reaches in the process high weight, which is not given the available space can be compensated for by counterweights on the crankshaft can. Overall, there is the disadvantage of these designs in that the moving masses, namely pistons and connecting rods, get bigger and thus also master greater mass forces are.

In order to avoid these disadvantages, an attempt has been made to make a change the compression ratio to create that you have the crankshaft stored in eccentric rings, the in turn are rotatably mounted in the engine block and with connected to an actuator. By twisting of the eccentric rings it is possible to position the crankshaft in this way to shift that one in the top dead center position Piston this more or less distance to the cylinder ceiling comply. For this purpose it is provided in DE-A-30 04 402 that everyone Eccentric ring is connected to a gear, each in a pinion engages on a parallel to the crankshaft extending actuator shaft is arranged with an actuator communicates. In addition to a significant constructive and structural effort also results in an increased Space required to accommodate the eccentric rings and the adjacent gears.

An arrangement of this type is also known from DE-A-36 01 528, in which the eccentric rings bearing the crankshaft bearings with a concentric to the eccentric rings and extending the entire length of the engine block extending cylinder part shell are connected. The cylinder shell is on the outside with a tooth segment provided, in the one connected to an actuator, transversely engaging adjusting screw running to the crankshaft. This System has a favorable length for the crankshaft bearing the disadvantage that here a very compact component intended for the synchronous adjustment of the eccentric rings is and that due to the eccentricity of the crankshaft axis effective to the bearing axis of the eccentric rings during operation moments are only recorded via the adjustment screw can be. Because with such an adjustment screw always only a few teeth with a low degree of coverage are engaged stand, arises due to those occurring in operation pulsating loads a considerable material stress. Even a slight play between the tooth segment and Adjusting screw can become a rapidly progressing one here Wear.

From DE-A-36 44 721 a system is also known in which everyone Eccentric ring connected to a laterally protruding lever is that carries a sliding block at its free end. An actuating shaft is mounted on the side parallel to the crankshaft, which is provided with an actuator and which with fork-shaped Claws are provided, each of the sliding block of an eccentric ring. Since sliding blocks are practically not with this system there is also the Disadvantage that due to the operation of the eccentric rings acting pulsating moments to considerable stress of the system lead in this area, which with an increasing Locked in the area of the sliding block guide is.

DE-A-198 41 381 discloses further embodiments for such Adjustment devices known. All known embodiments however require special designs of the engine block.

The invention has for its object a piston internal combustion engine with adjustable compression ratio create that structurally simpler and cheaper to build is finished.

This object is achieved according to the invention by a piston internal combustion engine with the features specified in claim 1. A piston internal combustion engine of this type has the advantage that through the side next to the crankshaft and parallel for this purpose, the control shaft is mounted in an area of the engine block can be arranged by the between the cylinders effective on the one hand and the crankshaft on the other Forces are practically not burdened. This offers the big one Advantage that the structures designed for power transmission of the engine block are not disturbed and accordingly an existing engine block due to low and relatively easy change of shape by adding the Storage area for the adjusting shaft can be changed. The Arrangement can be made so that the outer Dimensions of the crankcase are practically not changed and therefore no enlargement of the engine compartment for the vehicle becomes necessary. It is particularly useful here if the control shaft with its bearings next to each side the main camps is arranged.

Since the running in the direction of the cylinder axis and force components acting on the crankshaft by a measure the eccentricity a corresponding torque in the eccentric rings initiate that via the actuating arms and the actuator must be included, the above mentioned Systems, as far as the transmission of the actuating forces via gears takes place, the disadvantage that the gears in the course operation due to the unavoidable backlash refuse. By using the pinion element according to the invention the possibility is given by bracing the two pinions of the pinion element against each other Exclude tooth play. This can be done in the simplest way by the fact that the tooth element each have an actuating arm such a pinion element acts in each case.

In an advantageous embodiment of the invention, that the tooth elements from neighboring control arms over a pinion element are interconnected. This is done from one end of the control shaft to the other end of the Control shaft a chain-like transmission of the control torque, because each one of the actuating arms is springy from one side braced pinion and from the other side engages with the control shaft firmly connected pinion. This In a further embodiment of the invention, arrangement allows that the two pinions of the pinion element via a torsion spring tube are interconnected. Such a pinion element is easy to manufacture and allows a cheap one Design of the tension between the two pinions required springs to use a torsion spring tube, since the length of the pinion element, i.e. H. the distance between the two pinions approximately the distance between two cylinder axes or between two main camps.

In an advantageous embodiment of the invention, that the control shaft is hollow and that the pinion elements each connected to it by local expansion are. The hollow shaft is expanded with the pinion element only in the area of the pinion that is fixed to the shaft to be connected. This gives you the opportunity to Inner diameter of the torsion spring tube on the one hand and the To dimension the outside diameter of the undeformed hollow shaft so that a plain bearing fit is given and accordingly the relatively rotatable pinion accordingly on the hollow shaft is stored, while the pinion to be fixed by the Widening of the hollow shaft is firmly connected to this.

In an expedient further embodiment of the invention, that the control shaft with bearing bodies for storage in Engine block is provided, whose outer diameter is larger than the outer diameter of the pinion. This eliminates the need the corresponding for the storage of the control shaft To divide the area of the engine block. Rather, it is possible corresponding through holes through the corresponding Work in areas of the engine block. Because the bearings for the Control shaft is always conveniently located next to a main crankshaft bearing are arranged, but there is also Possibility of the bottom of the engine block in full Length covering frame or lattice-shaped bearing component in the form of a so-called bed plate, correspondingly to provide the bearings for the control shaft.

The bearing body can also be expanded with the Control shaft are firmly connected. Because the control shaft is not is rotated continuously, the arrangement is special Plain bearing bushes or plain bearing shells are not required. The actuating shaft with its bearing bodies can be directly in the material the engine block, which is made of gray cast iron or light metal cast can be produced, stored. The oil supply can via so-called catch holes.

In a preferred embodiment of the invention, that the eccentric ring is composed of two sections is, the division plane through the axis of rotation the crankshaft runs and that at least a portion with an actuating arm is provided with a tooth element. In a variation for this it is possible that each section with an actuator arm is provided with a tooth element, the two actuating arms overlap the bearing housing assigned to the eccentric ring on the side. Because of the special design of the pinion element an existing backlash can be composed provided in a preferred embodiment of the invention, that in each case the sections of the eccentric rings with adjusting arm and Tooth element are integrally formed, in particular are designed as a sintered part. So it offers a significant reduction in costs because of the component "Eccentric ring with adjusting arm and tooth elements" a processing only for the outer circumference of the Eccentric ring and as a bearing surface for the crankshaft serving inner circumference of the eccentric ring. The accuracy of the toothing is in a manufacture as Sintered molded part is sufficient, especially for adjusting the compression ratio the actuating arm is only proportionate small adjustment angle must be pivoted back and forth.

A separate, Actuator controllable via a motor control device be provided with countershaft transmission.

In a preferred embodiment of the invention is a Actuator provided, which is formed by a with the Drive shaft connected drive wheel with large outer diameter, the two drive wheels with small diameter in constant engagement are assigned, each with a switchable Coupling are connected, the drive on the opposite side optionally drivable and with a drive with constant direction of rotation is connectable by switching, as well as by a switchable parking brake, each time the Clutch releases. A magnetic one is preferred Slip clutch, on the one hand, a smooth rotation of the Actuating shaft causes and on the other in addition to that by given the small drive wheels and the large driven wheel Translation allows a reduction in the adjustment speed. But this also gives you the opportunity to Actuator on the face of the piston internal combustion engine in to integrate one of the belt drives and so via the crankshaft drive. The driving parts then run during operation the clutch on the two small drive wheels freely with and only occurs when one of the two clutches is switched a torque introduction on the switched clutch. To the release by the parking brake then turns the control shaft and thus a change in the displacement.

Fig. 1

eine perspektivische Schemadarstellung eines Vierzylindermotors zur Erläuterung des Grundprinzips,

Fig. 2

einen Vertikalschnitt durch einen Motorblock im Bereich eines Kurbelwellenhauptlagers gem. der Linie II-II in Fig. 3,

Fig. 3

einen Horizontalschnitt gem. der Linie III-III in Fig. 2.

Fig. 4

ein Teilstück eines Exzenterringes in einer Stirnansicht,

Fig. 5

eine Aufsicht auf das Teilstück gem. Fig. 4,

fig. 6

ein zugeordnetes Teilstück eines Exzenterringes in einer Stirnansicht,

Fig. 7

eine Aufsicht auf das Teilstück gem. Fig. 6,

Fig. 8

schematisch als Stirnansicht auf eine Kolbenbrennkraftmaschine die Antriebsseite des Stellantriebs,

Fig. 9

einen Schnitt gem. der Linie IX-IX in Fig. 8.

The invention is explained in more detail with reference to schematic drawings of an embodiment. Show it:

Fig. 1

1 shows a perspective schematic representation of a four-cylinder engine to explain the basic principle,

Fig. 2

a vertical section through an engine block in the area of a main crankshaft bearing acc. the line II-II in Fig. 3,

Fig. 3

a horizontal section acc. the line III-III in Fig. 2nd

Fig. 4

a portion of an eccentric ring in an end view,

Fig. 5

a supervision of the section acc. Fig. 4,

fig. 6

an associated section of an eccentric ring in a front view,

Fig. 7

a supervision of the section acc. Fig. 6

Fig. 8

schematically as a front view of a piston internal combustion engine, the drive side of the actuator,

Fig. 9

a cut acc. the line IX-IX in FIG. 8.

As can be seen from the schematic illustration in FIG a crankshaft 1 with its crankshaft bearings 2 in eccentric rings 3 mounted, which in turn can be rotated in corresponding Support bearings 4 of an indicated engine block stored are. With the crankshaft 1 are the connecting rods 5 each connected here only schematically indicated piston 6. The Crankshaft 1 is shown in a position in which the pistons 6.1 and 6.4 are in the top dead center position, while the pistons 6.2 and 6.3 are in the bottom dead center are located.

Each eccentric ring 3 is rigidly connected to an actuating arm 8, which is provided with a tooth element 9 at its free end is. The tooth elements 9 each have a pinion element 10 engaged with one in the side of the engine block and connected to the crankshaft 1 mounted actuator shaft 11 are. The adjusting shaft 11 is only indicated here Actuator 12 connected.

By rotating the adjusting shaft 11 by a corresponding one Setting angle α in one of the directions shown Double arrow, the eccentric rings 3 each around their Fixed axis of rotation 14 in the engine block rotated accordingly and thereby the eccentrically mounted in the eccentric rings 3 Crankshaft 1 with their crankshaft bearings 2 accordingly raised or lowered up or down. This ensures that corresponding pivoting the eccentric rings 3 up or down the piston 6 with their Piston plate correspondingly closer or farther from Combustion chamber roof and thus the compression ratio can be changed in a targeted manner. In each settings specified by the operating conditions then the entire arrangement via one with the actuator 12 connected, not shown here parking brake held.

2 is an end view in a partial vertical section to a main bearing area of the crankshaft in the engine block shown according to Fig.1. A more detailed description it is not necessary because the individual components based on their Reference symbols can be identified in connection with FIG. 1.

The sectional view acc. Fig. 3 leaves the constructive assignment the control shaft 10 and a special embodiment recognize the pinion elements.

As can be seen in connection with FIGS. 4, 5 and 5, 6 is, the eccentric rings 3 are each with two parallel Arm 8.1 and 8.2 provided, each at their ends are provided with corresponding tooth elements 9. The tooth elements 9 of an eccentric ring 3 are each with axial Spaced from each other. Only the eccentric ring on the end 3.1 is 8.0 with only one control arm and corresponding provided only one tooth element.

In the embodiment shown here, the pinion element 10 formed by two pinions 10.1 and 10.2, the firmly connected to one another via a torsion spring tube 15 are. The arrangement is such that the pinion element 10 firmly in the area of its pinion 10.1 the control shaft 11 is connected, for example by a Widen the hollow shaft or by a corresponding connection procedure, during the subsequent Area of the torsion spring 15 and the pinion 10.2 on the Actuating shaft 11 with respect to the pinion firmly connected to this 10.1 is relatively rotatable.

The adjusting shaft 11 is connected to bearing bodies 16, the Outside diameter is larger than the outside diameter of the pinion elements 10, so that the control shaft 11 with attached pinion elements 10 in total through corresponding holes in Engine block can be pushed through.

As already mentioned above, the eccentric rings are each formed from two sections 3.1 (Fig. 4) and 3.2 (Fig. 6).

As the supervision acc. Fig. 5 and Fig. 7 reveals are the two sections 3.1 and 3.2 designed so that each Section each an actuating arm 8.1 or an actuating arm 8.2 exhibit. The two sections 3.1 and 3.2 can then order the associated main or base bearing of the crankshaft 1 screwed together be so that the two control arms 8.1 and 8.2 the bearing on both sides in the direction of the adjusting shaft 11 overlap. Both control arms 8.1 and 8.2 are on the end each provided with a tooth element 9, each with a Pinion of the pinion element is engaged.

3, the arrangement is made so that starting from the actuating arm 8.0, the one assigned to it Pinion 10.1 is firmly connected to the actuating shaft 11 and Via the torsion spring tube 15, the pinion 10.2 with the tooth element 9 on the actuating arm 8.2 of the adjacent eccentric ring 3 is engaged. The individual are correspondingly continuous successive eccentric rings 3 each via pinion elements 10 connected together. Because the gearing of the pinion 10.1 compared to the pinion 10.2 of a pinion element 10 offset by a small amount in the circumferential direction is arranged, there is the possibility of mounting each the tooth elements connected to one another via the pinion element to brace against each other and so the backlash excluded. This makes it possible to cut the sections for the To produce eccentric rings, for example, as sintered components then the toothing of the tooth elements 9 is no longer processed need to be. In the same way it is possible, at least the pinion 10.1 or 10.2 of the pinion elements 10 manufacture as sintered parts, which then on one in its Wall thickness and its suspension properties given by the material according to dimensioned pipe firmly attached are, for example by shrinking.

8 and 9 is an exemplary and advantageous Embodiment for the actuator 12 shown.

How the front view acc. Fig. 8 and the associated Section in Fig. 9 reveals the actuator 12 in essentially formed by an output gear 17, for example a gear that is fixedly connected to the actuating shaft 11. The driven wheel 17 has two drive wheels 18.1 and 18.2 small diameter associated with the permanent engagement with the Output wheel 17 stand.

As can be seen from the sectional view in FIG. 9, the two small drive wheels 18.1 and 18.2 each with one switchable coupling 19.1 and 19.2 connected as magnetic Slip clutches are formed. The driving part 20.1 and 20.2 of the slip clutches is in the unswitched state freely rotatable relative to the part to be driven 21.1 and 21.2, each connected to the drive wheel 18.1 or 18.2 is.

The driving part 20 of the two slip clutches is over a pulley 23 and connected to the crankshaft 1 a belt 22 driven, the belt 22 on the two driving parts 20.1 and 20.2 is passed so that with the belt 22 running in the same direction (arrow 24) by switching the clutches the drive wheels 18.1 or 18.2 are turned in opposite directions can. Which by the displacement of the axis of rotation 13 of the Crankshaft 1 resulting change in the height of the pulley 23 with respect to the pivot block 14 of the engine block Eccentric rings 3 is through a corresponding belt tensioning device compensated, which is not shown here.

The driven wheel 17 is, as indicated in FIG. 9, a switchable parking brake 25 assigned by the in operation via the driven wheel 17, the control shaft 11 in each their set position is held and so that each set compression ratio is fixed. Should the compression ratio will be changed depending on the adjustment direction specified by the control device one of the two clutches 20.1 or 20.2 activated and the Parking brake 25 released, so that to change the Compression ratio specified by the control device Pivoting can be performed. Once the end position the parking brake is applied and the clutch switched off, so that the driving part 20.1 or 20.2 is again free in the direction of flow of the belt 22 can rotate predetermined direction of rotation without that via the drive wheels 18.1 and 18.2 a force effect takes place on the driven wheel 17.

Claims (10)

Piston engine with in line in an engine block arranged cylinders and pistons (6) guided therein, the are connected to a crankshaft (1) via connecting rods (5) Bearing (2) in eccentric rings (3) are arranged, which in turn rotatably supported in support bearings (4) in the engine block are and of which at least a part each with one Adjusting arm (8) is connected, which is at its free end Has tooth element (9), each with a pinion element (10) is engaged with one in the side of the engine block and actuating shaft (11) mounted parallel to the crankshaft (1) is connected, which is connected to an actuator (12) stands, the scoring element (10) by two pinions (10.1, 10.2) is formed, of which the first pinion (10.1) is fixed is connected to the actuating shaft (11) and the second pinion (10.2) rotatable and resilient relative to the first pinion (10.1) is arranged braced. Piston-type internal combustion engine according to claim 1, characterized in that the tooth elements (9) of adjacent adjusting arms (8) are connected to one another via a pinion element (10). Piston-type internal combustion engine according to claim 1 or 2, characterized in that the two pinions (10.1, 10.2) of a pinion element (10) are connected to one another via a torsion spring tube (15). Piston-type internal combustion engine according to one of claims 1 to 3, characterized in that the adjusting shaft (11) is hollow and the pinion elements (10) are each firmly connected to it by local expansion. Piston-type internal combustion engine according to one of Claims 1 to 4, characterized in that the actuating shaft (11) is provided with bearing bodies (16) for bearing in the engine block, the outer diameter of which is larger than the outer diameter of the pinion elements (10). Piston-type internal combustion engine according to one of claims 1 to 5, characterized in that the eccentric ring (3) is each composed of two sections (3.1, 3.2), the plane of division passing through the axis of rotation (13) of the crankshaft (1) and that at least one section (3.1) is provided with an adjusting arm (8.1) with tooth element (9). Piston-type internal combustion engine according to one of claims 1 to 6, characterized in that each section (3.1, 3.2) of an eccentric ring is provided with an actuating arm (8.1, 8.2) with tooth element (9), the two actuating arms (8.1, 8.2) being the eccentric ring (3) grasp the associated bearing housing (4) laterally. Piston-type internal combustion engine according to one of claims 1 to 7, characterized in that the sections (3.1, 3.2) of the eccentric rings (3) with adjusting arms (8.1, 8.2) and tooth element (9) are integrally formed, in particular as a sintered part. Piston internal combustion engine according to one of claims 1 to 8, characterized in that the actuator (12) is formed by a driven wheel (17) with a large diameter connected to the adjusting shaft (11), the two drive wheels (18.1, 18.2) with a small diameter in continuous engagement are assigned, which are each connected to a switchable clutch (20), which can be connected on the drive side in the opposite direction, optionally with a drive with a constant direction of rotation by switching, and by a switchable parking brake, which releases when the clutches are switched on. Piston-type internal combustion engine according to one of claims 1 to 9, characterized in that the clutch (20) is designed as a magnetic slip clutch.

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