WO2013160501A1 - Kinematic chain for positioning eccentric bearings which rotate on the crankpins of the crankshaft of an engine with a variable compression ratio - Google Patents

Description

 Kinematic chain to position eccentric bearings that rotate on the crankshaft wrists of a variable compression ratio motor.

FIELD OF THE INVENTION

The present invention concerns a kinematic chain used to change the angular position of eccentric bearings that rotate on the wrists, axles of the connecting rods, in order to vary the piston stroke and, consequently, the compression ratio. It is intended to achieve a reliable and easily realizable set that allows this technique to be carried out. There are currently experimental variable compression engines, mounted on pre-series vehicles, which demonstrate the effectiveness of this technology. In traditional engines, when the volumetric compression ratio is fixed, it is designed to favor, to a large extent, maximum power, making the engine run improperly at medium or low load, a situation that occurs in more than 95% of the Life time of a vehicle. (An average car uses only 30 kw to maintain 130 km / h, and in city traffic the average power required is usually less than 20 kw): with a variable compression system, the absolute pressure is maintained near the car. detonation in all circumstances, thus achieving optimum efficiency.

 In addition, providing it with an important power supply (2/1 or 3/1) high specific powers can be achieved (a current embodiment yields 220 Cv. With a 1600cc engine)

 This fact allows to use small motors (downsizing) whose optimum point of operation adapts much better to the most frequent circumstances of circulation.

 The current figures obtained by vehicles equipped with this system are extremely interesting: driving in the city, comparing engines of the same maximum power, a reduction of the consumption of the order of 30% is achieved.

The present invention that achieves exactly the same results (since these only depend on the range of variation of the compression ratio) has the advantage of being manufactured maintaining the same general structure of the engine, modifying only the crankshaft. Another favorable point is that to vary the compression, contrary to the existing embodiments, no fluid power is needed, an expensive technique that forces the oil pump to be sized and uses expensive valves. Nor does it use auxiliary motors, since this variation is achieved, using electric brakes by eddy currents.

 The low inertia of the system allows to travel the entire range of compression ratios (1/6 to 1/15) in less than a tenth of a second.

 Due to its technical characteristics, its field of application is very wide because it allows fuel savings, similar to that of hybrid technology cars, getting less expensive, lighter and wider vehicles, without sacrificing useful space.

The new regulations, which limit pollution, and the incessant price increase of fuel, will make variable compression ratio engines soon a real option.

DESCRIPTION OF THE RELATED TECHNIQUE

In order to vary the compression ratio, a large number of configurations have been devised throughout history that achieve a displacement of the upper dead center of the piston by modifying the volume of the combustion chamber. This restlessness begins in distant times giving rise to patents that are now in the public domain.

 The technique chosen in this project consists of eccentrics located between the foot of the cranks and the crankshaft that, depending on their relative position, increase or decrease, by a few millimeters the effective radius of the crank.

 This concept appears in old and some relatively recent patents such as the one listed below: GB 2258271 A and has been reproduced in the ANNEX of the drawings.

The present invention, takes up from these patents the idea of an eccentric bushing rotating around the mufflequilla, replacing the rest of the known kinematic chains with an original, the essential idea being to communicate the movement outside the crankshaft by means of an endless screw that it passes through it, and use some discs that, when slowed down, produce a relative movement that modifies the position of the eccentric bearing, the crank shaft.

EXPLANATION

In order to vary the compression, the volume of the combustion chamber is varied by making the position of the dead-top point variable. This is achieved by modifying the effective measurement of the crankshaft crank, by rotating an eccentric Fig. 1 (1) around the wrist where the connecting rod rests. To move said eccentric movement is used that comes from a coaxial axis Fig. 2 (2) that rotates in the center of the crankshaft. This axis can be connected to the eccentric in several ways:

 - By means of a pinion (3) that meshes with another pinion (4), integral with the eccentric bearing (1), represented in Fig. L and 2. This solution that appears in various patents is problematic because the teeth of the gears are subjected to strong efforts and, to oversize them you can only increase their width, reducing the space of the doll.

 - By means of a "simple articulated quadrilateral" formed by a connecting rod Fig. 3 (11) that joins the eccentric to the crank integral with the coaxial axis.

 -By a double articulated quadrilateral Fig. 4; which prevents the bars (12) that connect with the cranks to work to extension, thus allowing to dispense with the axes of their joints.

 - By means of a pinion Fig. 5 (13) integral to the coaxial axis (2), and a plate (14), integral to the eccentric bearing of the wrist, in which a groove has been made and provided with internal gear teeth (fifteen). This choice allows transmitting, approximately 4 times more torque, due to the increase in the actuation lever and due to the improvement in the degree of coating of the crown and pinion teeth.

 In the event that a removable crankshaft is not used, the eccentric wrists can be made of two pieces. Fig. 6 and 7.

The other end of the coaxial axis, reaches a cavity Fig. 1 (5) and ends in a toothed crown Fig. 2 (6) that meshes, irreversibly, with an endless screw (7). Said screw communicates the movement by means of pinions to a conical pinion (8). This conical pinion meshes with a crown (9) integral with a disc (10). The conical pinion meshes with another crown integral to another disk (16) shown in Figs. 1 and 9. When the crankshaft rotates and the compression is not intended to vary, the entire assembly moves as one piece, without relative movement. The efforts produced by the connecting rods cannot rotate the eccentric because, the crown worm assembly is irreversible in this regard.

 By slowing one of the discs, by means of a brake Fig. 23 (20), a relative movement is created with respect to the crankshaft that rotates the eccentric bearing, and consequently, modifies the position of the piston and the compression ratio. Depending on the braked disc, a different direction of rotation of the eccentric is obtained.

 The cavity where the endless screws and their crown are housed can be manufactured as a separate piece Fig. 8, adjustable to the crankshaft; or it can be integrated into the crankshaft itself Fig. 10 (5) by constructing the whole assembly in one piece. Figs.11,12 and 13 (5) The crown Fig.2 (6) that meshes with the two endless screws (7), does not need any axle in its vicinity, ensuring that the screws share the force in a balanced way.

The movement is transmitted to the successive eccentric bearings of the various cylinders, repeating the connection by means of sections of coaxial inner shafts and the elements described above Fig. 1 (17).

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 and 2 represent half of a crankshaft, with eccentric bearings (1), and the kinematic chain to rotate them, consisting of:

 gears (4) and (3), coaxial shaft with the crankshaft (2), crown (6) and its worm (7), conical pinion (8) and crown (9) and brake disc (10)

Fig. 3 represents an alternative to guide the eccentric bearing (1) from the coaxial axis, by means of an articulated quadrilateral thanks to the rod (11)

 Fig. 4 represents an alternative to guide the eccentric bearing (1) from the coaxial axis, by means of a double articulated quadrilateral that uses pushers that work only on compression (12)

 Fig. 5 represents an alternative solution to guide the eccentric bearing (1) from the coaxial axis, by means of a pinion that meshes with an internal toothed crown, managing to reduce the stresses and with improving the degree of coating.

Figs. 6 and 7 represent eccentric bearings manufactured in two parts to be assembled in the case of using a crankshaft manufactured in one piece, not removable.

 Figs. 8 and 9 represent the block that houses the crown and the endless screws. This block can be built separately, and then attached to the crankshaft. In Fig. 9; the two brake discs (10) and (16) are shown, meshing with the conical pinion (8). Fig. 10 represents the crankshaft made in one piece.

 Figs. 11, 12 and 13 represent the housing, of the worm and crown screws, practiced in the crankshaft.

 Fig. 14 depicts the crown and split discs.

 Fig. 15 represents part of the crankshaft with a groove (19) where the toothed crown of Figs. 16,17,18 and 19 circulates.

 Fig. 20 represents the direct transmission of crown screws using hypoid gears.

 Figs. 21 and 22 represents the screw crown transmission using a spiral screw.

Fig. 23 represents the system with part of the crankshaft and the right disk sectioned. The block where the screws and their crown are housed is not drawn. The electric brakes act independently on each disc. DESCRIPTION OF THE REFERRED EMBODIMENT

In order to vary the compression, Fig. 1 and 2, the effective measurement of the crankshaft crank is modified by rotating an eccentric bearing (1) around the wrist where the connecting rod is supported. This is achieved by rotating a coaxial shaft (2) that rotates in the center of the crankshaft. In this embodiment, this shaft is connected to the eccentric bearing thanks to a pinion (3) that meshes with another, integral with the eccentric (4) The other end of the coaxial axis, reaches a cavity fig.1, (5) and ends in a toothed crown (6) that meshes, irreversibly, with an endless screw (7). Said screw communicates the movement by means of pinions to a conical pinion (8). This conical pinion meshes with a crown (9) integral with a disc (10). The conical pinion meshes with another crown integral to another disc that is NOT shown in Fig. 2 for clarity, but in Fig. (1)

 When the crankshaft rotates, and the compression is not intended to vary, the entire assembly moves as one piece, without relative movement. The efforts produced by the connecting rods cannot rotate the eccentric, because the worm screw assembly is irreversible in this direction.

 By slowing down, by means of a brake Fig. 23 (20), one of the discs, a relative movement is created that rotates the eccentric wrist, and consequently, modifies the position of the piston and the compression ratio.

Claims

1) Kinematic chain to position eccentric bearings that rotate on the crankshaft wrists of a variable compression ratio motor, consisting of a mechanical assembly that communicates the movement of brake discs or drums, to the eccentric bearings, on which they support the connecting rods, using a coaxial inner shaft with the crankshaft shaft, characterized in that it comprises:  - two mechanical brakes Fig. 23 (20) or electric whose discs Fig. 1 (10) and (16), or brake drums, rotate coaxial to the crankshaft, and each gear, by means of a toothed crown (9), with the same, or same, pinions (8), having this, or these, pinions an axis of rotation perpendicular to the crankshaft axis;  - one, or ones, endless screws fig. 2 (7), with rotation axes perpendicular to the crankshaft axis, which are connected with said pinions and that engage in its central part with a crown (6) integral with the inner axis (2);  - a transmission mechanism that connects the movement of the inner shaft with the eccentric bearing (1), connecting rod shaft. 2) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrists of a variable compression ratio motor according to claim 1 characterized in that a crank is incorporated in the end of the inner shaft that reaches the plane of the wrist, by means of a bar fig. 3 (11), transmits the movement to an eccentric bearing extension. 3) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrists of a variable compression ratio motor according to claim 1 characterized in that two opposite cranks are incorporated in the end of the inner shaft that reaches the plane of the wrist. , using two bars fig. 4 (12), transmit the movement to two cranks in solidarity with the eccentric bearing, these cranks being parallel to the previous ones and of the same measures, the assembly forming a double articulated quadrilateral, keeping the bars that connect the cranks, always parallel and working only to compression, avoiding the need to use through axes in their joints. 4) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft muffles of a variable compression motor according to claim 1 characterized in that a pinion is engaged in the end of the inner shaft that reaches the plane of the wrist inner teeth (15) made in a groove contained in a plate fig. 5 (14) in solidarity with the eccentric bearing. 5) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrists of a variable compression motor according to claim 4 characterized in that in the internal faces of the crankshaft cranks there are grooves fig. 15 (19) and one central hole (18), which does not pass through, which allows the teeth of the pinion of the internal shaft (13) and the teeth of the plate integral to the eccentric fig. 17. 6) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrenches of a variable compression motor according to claim 5 characterized in that the eccentric joint plate is made without groove, projecting a part, of internal toothed crown, transversely fig. 16 (21). 7) Kinematic chain for positioning eccentric bearings that rotate on the wrists of a variable compression motor according to claim 1 characterized in that the housing of the worm and crown screw assembly is manufactured integrated in the crankshaft fig. 10 (5), machining, in the same block of its material, the necessary cavities. 8) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrists of a variable compression motor according to claim 1 characterized in that it comprises eccentric bearings fig. 6, matches, which allow to mount on a crankshaft that has been manufactured in one piece. 9) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrists of a variable compression motor according to claim 1 characterized in that the brake discs, or drums, have uneven moment of inertia, causing a rotation when a engine speed change. 10) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrists of a variable compression motor according to claim 1 characterized in that the inner shaft is mounted floating, with a single support at the end near the wrist, the other end positioned exclusively by the crown gear fig. 2 (6) that supports symmetrically in the two endless screws. 11) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrists of a variable compression motor according to claim 1 characterized in that the actuation of the brakes is controlled through a system that receives information of the start of auto detonation. 12) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrists of a variable compression motor according to claim 1 characterized in that a position transducer is used that measures the position of one of the connecting rods corresponding to the lower dead center of your piston 13) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrists of a variable compression motor according to claim 1 characterized in that hypoid pinions fig. 20 (22) integral to the endless screws, which engage directly with the crown integral to the brake disc. 14) Kinematic chain for positioning eccentric bearings that rotate on the crankshaft wrists of a variable compression motor according to claim 1 characterized in that an oil-driven or electric-controlled brake device is incorporated that acts at a point in the chain kinematic and blocks the relative motion of eccentric bearings.  15) Kinematic chain for positioning the crankshaft eccentric wrists of a variable compression motor according to claim 8, characterized in that the split eccentric bearings are joined together by means of FIG screws. 25 with double reverse propeller, turning them with a wrench that passes through one of the pieces, and the screws being initially located between the two pieces and beginning to be screwed simultaneously on the two.  16) Kinematic chain for positioning the crankshaft eccentric wrists of a variable compression motor according to claim 1 characterized in that the discs are braked by permanent magnets, FIG: 26 fixed to cranks and said cranks moving by means of a mechanical, electrical or fluid power, in such a way that the magnetic flux of the magnets crosses the discs and slows their movement by means of eddy currents.  17) Kinematic chain for positioning the crankshaft eccentric wrists of a variable compression motor according to claim 1 characterized in that the discs or drums are braked by implanting permanent magnets that rotate jointly with them FIG. 27 such that they become the rotors of an electric machine, said rotors rotate within fixed stators, which convert the set into two electric generators, increasing the braking torque by requesting more current from said generators.  18) Kinematic chain for positioning the crankshaft eccentric wrists of a variable compression motor according to claim 1 characterized in that a single disc or drum is used by implanting permanent magnets that rotate in solidarity FIG. 28 in such a way that they become the rotor of a electric machine, said rotor rotates inside a fixed stator, which converts the assembly into a reversible electric machine that brakes the disc when it works as a generator and accelerates it when it works as a motor.