EP1197640B1 - Multi-configuration valve drive - Google Patents

Abstract

The valve timing control comprises three sets of equipment (11,12,13) each of which comprises a stop (31,32,33), a rocker (41,42,43) and a cam (51,52,53). Two sets of equipment (11,12) are specifically dedicated to the control of two valves (21,22) and the third set simultaneously controls the two valves and comprises an adjustable stop (33) allowing it to be active or inactive. At least one of the two sets of equipment specifically dedicated to the control of the two valves is also provided with an adjustable stop enabling it to be active or inactive.

Description

The present invention relates, in general, a valve distribution control device for thermal motor.

More specifically, the invention relates to a valve distribution control device for engine, of the type that includes at minus a first, a second, and a third crew, and a first and a second valve to which the first and second crews are respectively dedicated, each crew including a stop, a rocker and a cam associated with each other and relating to this crew, each rocker having one end of support taking support, at least under conditions determined, on the associated stop, and one end actuation remote from the support end, each cam being rotated at an angular speed identical for the three crews and moving, at least under determined conditions and according to an angle of rotation of this cam, the associated rocker, each valve being resiliently biased toward a position of rest, which she adopts by default, and being moved towards a maximum actuation position, at least in conditions determined, by the end actuation of the rocker of the crew assigned to it dedicated, the third stop selectively adopting a state rest, for which the third rocker remains inactive, and an active state, for which the third cam moves simultaneously, via the third rocker, the first and second valves to a corresponding maximum actuation position, the rest position and the first actuation position maximum adopted by the first valve controlled by the first rocker being separated from each other by a first distance, the rest position and the second maximum actuation position adopted by the second valve controlled by the second rocker being separated from each other by a second distance, and the position rest and third maximum actuation position that each of the first and second valves adopt controlled by the third rocker being separated from each other by a third, different distance first and second distances.

A device of this type is for example described in patent documents FR-2 674 287 and EP 0 462 853 A and makes it possible to vary the amplitude of the lift by one or two valves and / or the opening law of this or these valves.

The efforts made in recent years to increase engine performance have shown the importance of the influence of the command of fuel distribution on reducing the consumption of these engines and their speed, in particular.

Nevertheless, the increased control of the position of valves introduces a priori a greater complexity of structure, and can therefore only be considered if the resulting structure remains simple enough to be practically implemented with negligible additional cost.

In this context, the object of the invention is specifically to propose a device for controlling distribution easy to implement and yet very versatile, i.e. able to take a number of relatively high configurations.

To this end, the control device for distribution of the invention, moreover in accordance with the generic definition given in the preamble above, is essentially characterized in that the first stop selectively adopts a rest state, for which the first rocker remains inactive, and an active state, for which the first cam moves, via from the first rocker, the first valve to its first maximum actuation position when the third stop is in its rest state.

Preferably, the second stop adopts itself selectively a state of rest, for which the second rocker remains inactive, and an active state, for which the second cam moves, through the second rocker, the second valve to the second position maximum actuation when the third stop is in its resting state.

In this case, it is advantageous to provide that the first and second distances are different one of the other.

Furthermore, in the preferred embodiment of the invention, the third distance is made greater at the first and second distances.

• La figure 1 est une vue en perspective d'un dispositif conforme à un premier mode de réalisation de l'invention;
• Les figures 2a à 2e sont des vues de face du dispositif illustré à la figure1, représenté dans différentes configurations; et
• La figure 3 est une vue en perspective d'un dispositif conforme à un second mode de réalisation de l'invention.

Other characteristics and advantages of the invention will emerge clearly from the description given below, by way of indication and in no way limitative, with reference to the appended drawings, in which:

• Figure 1 is a perspective view of a device according to a first embodiment of the invention;
• Figures 2a to 2e are front views of the device illustrated in Figure 1, shown in different configurations; and
• Figure 3 is a perspective view of a device according to a second embodiment of the invention.

As previously announced, the invention relates to a valve distribution control device which is intended to equip a heat engine, and which comprises essentially three crews 11 to 13, and two valves 21 and 22 to which the two extreme crews 11 and 12 are respectively dedicated.

Each crew includes a stopper such as 31 to 33, a rocker such as 41 to 43, and a cam such as 51 to 53, these elements being associated with each other at the interior of each crew 11, 12, and 13, and each of them being assigned to one of the crews.

Each rocker, such as 41 to 43, has a support end, such as 410, 420 and 430, and a actuation end such as 415, 425, and 435, away from the support end.

The bearing end of each rocker takes support, under conditions to be specified subsequently, on the stop, such as 31 to 33, which is associated with this rocker.

The three cams 51 to 53 are rotated at the same angular speed, each of them moving the rocker associated with it, such as 41 to 43, in conditions which will themselves be specified later, and according to a function of the angle of rotation of this cam.

Each valve 21 and 22 is resiliently biased, by a spring not shown, towards a rest position which it adopts by default.

The first valve 21 can however be moved towards a first position of maximum actuation, in conditions which will be specified later, by the actuating end 415 of the rocker 41 moved by the cam 51, the rest position and the first position maximum actuation being separated from each other by a distance denoted D1.

Similarly, the second valve 22 can be moved to a second actuation position maximum, under conditions to be specified subsequently, by the actuating end 425 of the rocker 42 driven by cam 52, the rest position and the second maximum actuation position being separated from each other by a distance denoted D2.

The third stop 33 is controlled by means known or accessible to those skilled in the art to adopt will a state of rest, for which the rocker associated 43 remains inactive, or an active state, for which the associated cam 53 moves simultaneously, by through the rocker 43, the two valves 21 and 22 towards a third maximum actuation position, separated from the rest position of these valves by a third distance D3 different from distances D1 and D2.

To this end, as shown in Figures 1 and 2, the third crew 13 is arranged between the crews extremes 11 and 12, and the actuating end 435 of the rocker 43 takes the form of a shaped pallet of so that you can wear both valves 21 and 22.

In the embodiment illustrated in FIG. 1, each of the rockers 41 to 43 constitutes a lever of the third type, that is to say that the associated cam, 51 to 53, press this rocker between the support end and the actuating end of this rocker.

In the embodiment illustrated in FIG. 3, each of the rockers 41 to 43 constitutes a lever of the first type, articulated around a tilt axis X disposed between its support end and its end actuation, the support end being selectively moved by the associated cam, 51 to 53, and through of the associated stop 31 to 33.

In the first case, the stop 33 is for example hydraulically controlled to be locked in translation or incompressible in length when it must adopt its active state, and to be on the contrary easily movable in translation or compressible when it must adopt its state of rest, this stop then being unable to provide stable support to the rocker.

In the second case, the stop 33 is for example hydraulically controlled to be incompressible in length when it must adopt its active state, and for on the contrary be easily compressible when it must adopt its state of rest, this stop being then unable to transmit the movement of the associated cam.

According to the invention, the first stop 31 is itself ordered by means known or accessible to the skilled person to adopt at will a state of rest, for which the associated rocker 41 remains inactive, and an active state, for which the associated cam 51 moves, by means of rocker 41, the first valve 21 to its first actuation position maximum, when the third stop 33 is in its state rest.

Similarly, the second stop 32 is preferably it also controlled by means known or accessible to the skilled person to adopt at will a state of rest, for which the second rocker 42 remains inactive, and an active state, for which the second cam 52 moves, via the second rocker 42, the second valve 22 to the second actuation position maximum, when the third stop 33 is in its state rest.

Finally, the first and second distances D1 and D2 are advantageously different from each other and both less than the third distance D3.

The operation of the device of the invention will be better understood with reference to Figures 2a to 2e which represent different configurations of the mode of realization illustrated in figure 1.

In FIG. 2a, the three stops 31 to 33 are in their resting state.

Cams 51 to 53 are then unable actuate rockers 41 to 43.

As a result, valves 21 and 22 remain stationary at their closing level N0, and the cylinder of the motor to which access is controlled by the device is disabled.

In FIG. 2b, the stops 31 and 33 are in their rest state, while the stop 32 is in its active state.

Cams 51 and 53 are impossible actuate rockers 41 and 43, but cam 52 on the other hand actuates the rocker 42.

Consequently, the valve 21 remains stationary, but the valve 22 moves, as a function of the rotation of the cam 52, between its rest position, which is located at the closing level N0, and its actuation position maximum, which is the position shown and which is located a level N1, separated from level N0 by the distance D2.

In FIG. 2c, the stops 32 and 33 are in their rest state, while the stop 31 is in its active state.

Cams 52 and 53 are impossible actuate rockers 42 and 43, but cam 51 on the other hand actuates the rocker 41.

As a result, the valve 22 remains stationary, but the valve 21 moves, as a function of the rotation of the cam 51, between its rest position, which is located at the closing level N0, and its actuation position maximum, which is the position shown and which is located a level N2, separated from level N0 by the distance D1 in the occurrence assumed to be greater than the distance D2.

In FIG. 2d, the stops 31 and 32 are in their active state, the stop 33 being alone in its state of rest.

Cam 53 is unable to activate the rocker 43, but the cams 51 and 52 operate in however the rockers 41 and 42, respectively.

Consequently, the valve 21 moves, in function of the rotation of the cam 51, between its position of rest at level N0 and its actuation position maximum at level N2.

Likewise, the valve 22 moves, depending on the rotation of the cam 52, between its rest position at level N0 and its maximum actuation position at level N1.

Finally in FIG. 2e, the stops 31 to 33 are shown in their active state.

Cam 53 actuates rocker 43, which in turn moves valves 21 and 22 simultaneously.

Each of these valves moves, depending on the rotation of the cam 53, between its rest position at level N0 and the maximum actuation position at level N3 imposed by cam 53, this actuating position being separated from the rest level N0 by a distance D3 in this case assumed to be greater than distances D1 and D2.

As one skilled in the art will readily understand reading of the above, the extreme positions N0 and N3 adopted by valves 21 and 22 would not modified, in the case illustrated in Figure 5e, if the stops 31 and 32 were placed in their position rest.

Assuming that the profiles of cams 51 and 52 locally cover the profile of cam 53 to distance from the highest point thereof, the laws of variation of the valve liftings 21 and 22 depending on the time, i.e. again as a function of the angle of rotation of the cams, would nevertheless be changed.

The stops can be ordered according to a technique known in itself, by solenoid valves (not shown) upstream of the engine oil circuit, these solenoid valves being themselves controlled by the engine control unit.

As will be understood by those skilled in the art, the device of the invention is not limited to the order of engine intake valves but is also applicable to the control of exhaust valves.

Claims (4)

1. Valve drive for thermal engine, comprising at least a first, a second and a third element (11, 12, 13) and a first and second valve (21, 22) to which the first and second elements (11, 12) are respectively assigned, each element incorporating a stop (31 to 33), a rocker switch (41 to 43) and a cam (51 to 53), which are interconnected and relate to this element (11, 12, 13), wherein each rocker switch (41 to 43) exhibits a support end (410, 420, 430) resting, at least under certain conditions, on the associated stop (31 to 33), and a driving end (415, 425, 435) at a certain distance from the support end, wherein each cam (51 to 53) is driven rotatorily at the same angular velocity for the three elements and displaces, at least under certain conditions and as a function of the angle of rotation of this cam, the associated rocker switch (41 to 43), wherein this valve (21, 22) is elastically loaded toward a position of rest, which it adopts by default, and is displaced toward a maximum drive position, at least under certain conditions, by the driving end (415, 425) of the rocker switch (41, 42) of the element assigned to it, wherein the third stop (33) selectively adopts a state of rest for which the third rocker switch (43) remains inactive, and an active state for which the third cam (53) simultaneously displaces, by means of the third rocker switch (43), the first and second valves (21, 22) toward a corresponding maximum driving position, wherein the position of rest and the first maximum driving position adopted by the first valve (21) controlled by the first rocker switch (41) are separated by a first distance (D1), wherein the position of rest and the second maximum driving position adopted by the second valve (22) controlled by the second rocker switch (42) are separated by a second distance (D2), and wherein the position of rest and third maximum driving position adopted by each of the first and second valves (21, 22) controlled by the third rocker switch (43) are separated by a third distance (D3), different from the first and second distances (D1, D2), characterised in that the first stop (31) selectively adopts a state of rest for which the first rocker switch (41) remains inactive, and an active state for which the first cam (51) displaces, by means of the first rocker switch (41), the first valve (21) toward its first maximum driving position when the third stop (33) is in its state of rest.
2. Valve drive according to Claim 1, characterised in the second stop (32) selectively adopts a state of reset for which the second rocker switch (42) remains inactive, and an active state for which the second cam (52) displaces, by means of the second rocker switch (42), the second valve (22) toward a second maximum driving position when the third stop (33) is in its state of rest.
3. Valve drive according to either of the preceding claims, characterised in that the first and second distances (D1, D2) differ from each other.
4. Valve drive according to any of the preceding claims, characterised in that the third distance (D3) is greater than the first and second distances (D1, D2).

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