Abstract:
An apparatus for converting or changing the operation of a charge valve of a combustion engine, which comprises a camshaft with at least one valve cam, a swing lever supported on a machine-mounted component, which comprises a contact element for maintaining a contact member in a disposition on the valve cam and which actuates the valve, a coupling member mounted on the swing lever, which, in a first position, translates a movement of the contact member via the valve cam to the swing lever and, in a second position, interrupts the movement translation, and a switch device for moving the coupling member between its first and second positions and retaining apparatus mounted on the swing lever for retaining the coupling member in its second position.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an apparatus for switching the operation of a charge valve of an internal combustion engine according to the main concept of the principal claim. 
     A reduction in the consumption of combustion fuel has, in recent times, assumed increasing importance. One possibility to thus reduce combustion fuel consumption, offered in connection with multiple cylinder motors, is the timed placement out of service of individual cylinders, whereby the remaining cylinders operate with a higher average pressure and, thereby, a reduced specific fuel consumption. To place a cylinder out of operation, not only an interruption of the combustion fuel delivery is required; as well, the charging flow to the corresponding cylinder must also be deliberately interrupted, in that the one or more charging valves, especially the inlet or intake valves, of the respective cylinder are placed out of operation. 
     A further, important development goal lies in the reduction or decrease of the pollutant content in the exhaust gasses. The starting points for such improvements are to be found in the valve opening functions which are accommodated to the respective operational ranges, whereby optimal combustion conditions can be achieved. 
     In view of the above-noted reasons, there is a strong need for an adjustable or, respectively, convertible valve operating apparatus. 
     DE 19 82 8945 A1 discloses an apparatus for the activation and complete de-activation of a charging valve. In connection with this apparatus, the retention of a coupling lever, whose position determines the activation or de-activation of the valve, is effected by means of an electro-magnet disposed in a motor housing or on the cylinder head. In total, this known apparatus requires modifications of the motor housing or the cylinder head, in order to be subsequently installed thereon at a post-engine manufacturing time. 
     EP 0 016 068 describes an apparatus for converting the operation of a charging valve of a combustion powered engine, which works with a swing lever and a contact lever disposed in contacting relation with the swing lever. A spring, which presses the contact lever into a following disposition on the camshaft, is supported between the swing lever and the contact lever, so that, in this regard, no modification of the cylinder head via a subsequent installation effort is required. The actuation and retaining apparatus for actuating the coupling member is, however, configured as a hydraulic cylinder mounted on the cylinder head or, respectively, the motor housing, the hydraulic cylinder having a tappet which engages a contact surface of a coupling lever which is secured in a non-rotating manner with the coupling member, so that a friction contact occurs between the tappet and the contact surface. The arrangement according to EP 0 016 068 requires, in total, considerable installation room and is, especially because of the hydraulic cylinder, not capable of being subsequently installed on the cylinder head without a necessary modification thereof. 
     EP 0 995 885 A2 describes a valve actuating mechanism with an outer swing lever for engagement with a cam during the high stroke thereof and an inner swing lever for engagement with a cam during a lower stroke thereof. The ends of the swing lever disposed adjacent the charge valve of a combustion engine are connected to one another via connecting taps. On the other ends of the swing lever, a locking mechanism is provided, which comprises a pin which is movable back and forth between a locking position and a release position. 
     DE 37 01 480 A1, which describes the state-of-the-art apparatus which is improved upon by the apparatus of the present invention describes a valve actuating system in which the spring which biases the contact lever in the direction of a disposition of the contact lever onto the cam is supported on the cylinder head. This means that an available cylinder head for the subsequent installation of the valve actuating system must be modified, which is expensive. Moreover, a hydraulic cylinder with a tappet is provided for the release, or respectively, the blocking, of the movement which is translated between the contact lever and the swing lever, with the hydraulic cylinder being provided with hydraulic fluid via a hydraulic element on which the swing lever is supported and the swing lever requiring bores, which are expensive to provide, for permitting passage therethrough of the hydraulic fluid. 
     The present invention inventively provides a solution which advances the state-of-the-art apparatus, in that it has a simple configuration for a conventional combustion engine and can be installed thereon with the least possible modification while providing a high measure of operational reliability. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, the spring which biases the contact lever in a direction into a disposition of the contact lever on the valve cam extends directly between the swing lever and the contact lever so that, in this regard, no modification of the cylinder head is required. 
     Furthermore, the respective movement of the coupling member of the apparatus into its first and second positions is deliberately and synchronously effected by the rotation of the camshaft, so that the coupling member need only be retained in its second position. This permits a simple configuration of the retaining apparatus. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in the following description in connection with the schematic drawings and is explained in further details therewith. 
     The Figures of the drawings show: 
     FIG. 1 is a first embodiment of the inventive apparatus in an exploded perspective view, 
     FIGS. 2 and 3 are two perspective views of the assembled apparatus shown in FIG. 1, 
     FIG. 4 shows the arrangement of FIG. 1 at a different view thereat of the exploded perspective illustration of the arrangement, 
     FIGS. 5 and 6 are two perspective views of the embodiment shown in FIG. 1 from different viewpoints, 
     FIGS. 7 and 8 show a modified embodiment of the apparatus in perspectives similar to those shown, respectively, in FIGS. 5 and 6, 
     FIGS. 9 and 10 are perspective views similar to those of FIGS. 2 and 3 of a modified embodiment of the inventive apparatus, 
     FIG. 11 shows the embodiment of the apparatus as shown in FIGS. 9 and 10 in an exploded perspective view, 
     FIGS. 12 and 13 show several functional components of the apparatus according to the two different positions of the coupling member shown in FIGS. 9-11, 
     FIG. 14 is a detailed view of the engagement between a blocking bolt and a coupling lever, and 
     FIG. 15 is an exploded view of a further embodiment of the inventive apparatus. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     In all of the hereinafter following figures, functionally similar building components are designated with the same reference characters. 
     As seen in FIGS. 1 to  3 , a swing lever, which is collectively designated with the reference character  10 , comprises two swing arms  12  extending parallel to one another which are rigidly connected to one another at their lower rear portions via a flange  14  (FIGS. 4 and 5) or are, respectively, unitarily connected with this flange. The swing lever arms, in their rear regions in the vicinity of the flange  14 , are provided with holes  16 , in which a coupling bolt  18  is rotatively mounted, the coupling bolt having a cut out  20 . A coupling lever  22  is secured in a non-rotating manner to the coupling bolt  18 , the coupling lever being biased, in the installed condition of the coupling bolt  18  in the swing lever  10 , in a counter clockwise direction by a rotation spring  24  connected to the coupling lever and the swing lever  10 . 
     A contact lever, which is collectively designated with the reference character  30  is, in a manner similar to the swing lever  10 , configured with two contact lever arms  32 , which are rigidly connected to one another by a flange  33  (FIG. 4) or, respectively, are unitarily rigidly connected with one another. 
     The contact lever  30  is dimensioned such that it is receivable between the arms of the swing lever  10 . By means of a bolt  34 , which extends through pivot openings  36  at the forward end of the arms  12  and  32  and, as desired, is rotatably disposed therein via bushings  38 , the contact lever  30  is rotatable relative to the swing lever  10 . In the assembled condition of the swing arm  10 , a spring  44  is arranged between an appendage  40  projecting from the swing arm  10  and a bracket  42  provided on the contact lever  30 , the spring  44  biasing the contact lever  30  for a swing movement in the counter-clockwise manner relative to the swing lever  10 . 
     The contact lever arms  32  are provided at spacings from the pivot openings  36  with each having a respective additional pivot opening  46 , the pivot openings  46  securing between the arms  32  a rotation bolt  49  (FIG. 4) on which a contact roll or roller  48  is mounted. 
     On the right-hand swing lever arm  12 , as seen in FIG. 1, an extension  50  is provided on which an electromagnet  52  is mounted between the two arms  12  by means of a screw  53 , the electro-magnet comprising an electro-magnetically actuable blocking bolt  54  which can be extended outwardly into a hole  55  formed in the extension  50  and which cooperates with an appendage  56  (FIG. 14) of the coupling lever  22 . The coupling lever  22  comprises a contact surface  58  whose function is explained in more detail hereinafter. 
     The assembly of the above-described apparatus is as follows: 
     The coupling bolt  18  is assembled together with the coupling lever  22  and, with the intermediate arrangement of the rotational spring  24 , is extended through the holes  16  and axially non-displaceably secured to the swing lever  10 . The contact roller  48  is disposed on the contact lever  30  and the contact lever  30  is, via the bolt  34 , disposed on the swing lever  10 . The electro-magnet  52  is mounted to the extension  50  and is connected via non-illustrated connectors with a control device. 
     The entire working assembly, with the flange  14  of its swing lever  10  having one or more corresponding cut outs  60 , is disposed on a hydraulic power compensating element  62  which itself is on the cylinder head of a non-illustrated combustion engine, whereby the bolt  34  comes into contact with the shaft of a valve  64  which is pressed in its closing direction by a return spring  66 . 
     Thereafter, a camshaft  68  is installed which comprises a valve cam  70  for contacting the contact roller  48  and a coupling cam  72 , which cooperates with the contact surface  58  of the coupling lever  22 . As can be seen, the coupling cam  72  is arranged relative to the valve cam  70  such that the radially raised portion of the coupling cam is angularly coincident with the region of the base circle of the valve cam  70 . The camshaft  68  includes circular cylindrical contact surfaces  74  disposed on both sides of the valve cam which cooperate with the outer surface regions  76  of the swing lever arms  12 . 
     The arrangement between the cut out  20  in the coupling bolt  18 , the rotational position of the coupling lever  22  or, respectively, the rotational position of the coupling bolt  18 , and the arms  32  of the contact lever  30  is such that the arms of the contact lever  30  can pass through the cut out  20  of the coupling bolt  18 , if the coupling lever  22  is disposed in the position into which it moves in a clockwise direction, as shown in FIG. 1, due to the engagement of the coupling lever by the radially raised portion of the coupling cam  72 . If the coupling lever  22 , in contrast, is disposed in the position it assumes as it follows the base circle of the coupling cam  72 , the cut out  20  will have been rotated such that the arm  32  of the contact lever  30  cannot move past the cut out  20  but is, instead, as a result of the seating engagement between the coupling bolt  18  and the cut out  78  formed in the arm  32 , disposed in a form locking or keyed manner with the coupling bolt  18  so that the contact lever  30  cannot swing away from the swing lever  10 . 
     The arrangement between the outer surface region  76  of the swing lever arm  12  and the contact surface  74  of the camshaft  68  is such that the bolt  34  is constantly in at least adjacent disposition to the valve shaft, even if the contour of the valve cam  70  is not translated by the contact lever  30  to the swing lever  10 . 
     The function of the above-described apparatus is as follows: 
     It is assumed that the electro-magnet  52  is not actuated, so that the blocking bolt  52  does not extend through the hole  55  formed in the extension  50 . If the valve cam  70  presses the contact roller  48  downwardly, as viewed with respect to FIG. 1, the movement of the contact roller  48  is translated to the swing lever  10  due to the seating engagement between the contact lever  30  and the coupling bolt  18 , whereby the bolt  34  actuates the valve  64 . 
     The entire arrangement is disposed such that, as a result of the biasing force of the tolerance compensating element  62 , the contact roller  48  is disposed on the base circle of the valve cam  70  or, respectively, the outer surface region  76  of the swing lever arm  12  is disposed on the contact surface  74  of the camshaft  68 . If, during the effective operation of the base circle of the valve cam  70 , the coupling cam  72  engages the contact surface  58 , the coupling bolt  18  is rotated such that the cut out  20  rotates toward the arms of the contact lever  30  without the arms initially passing through the cut out. If the coupling lever  22  is retained by the actuation of the electro-magnet  52  through the rotational position of the radially raised portion of the coupling cam  72  (the blocking bolt  54  of the electro-magnet  52  grips or contacts the appendage  56  of the coupling lever  22 ), the contact lever  30  can, during the thereafter-following actuation, be moved by the valve cam  70  through the cut out  20  and thereby swing into the swing lever  10 , so that the valve  64  is not actuated. 
     It is to be understood that the electro-magnet  52  is respectively actuated by a non-illustrated control device at least for capturing or, respectively, retaining, the coupling lever  22 , if the contact roller  48  has contacted the base circle of the valve cam  70  or, respectively, has contacted the base circle of the coupling cam  72  as the coupling lever  22  is rotated in the clockwise direction as shown in FIG.  1 . 
     As can be understood from the foregoing description, the entire described building components can be mounted in a simple manner on the cylinder head before the installation of the camshaft instead of the mounting of a conventional valve actuating lever, whereby the cut out  60  formed in the flange  14  provides for a secure and reliable securement of the building components on the tolerance compensating element  62  and a cut out  80  formed in the bolt  34  and opening toward the valve shaft provides for a flat disposition on the valve shaft. 
     The afore-described arrangement can be reconfigured or modified in many ways: for example, the coupling bolt  18  can be provided with two cut outs  20  each of which corresponds to one of its arms. Furthermore, the coupling bolt  18  and the contact lever  30  can be configured such that the contact lever in one of the rotational positions of the coupling bolt lies against the coupling bolt and, in another rotational position, moves past the coupling bolt. 
     As seen in FIG. 1, in individually depicted broken-line positions, the cylindrical contact surfaces  74  are provided with assistance cams  82 . In one configuration of the camshaft  68  with such assistance cams  82 , in the event of a “captured” coupling lever (interruption of the movement translation between the contact roller  48  and the swing lever  10 ), the swing lever  10  is immediately or directly actuated by the assistance cams, which are disposed on the cuter surface regions  76 . In this manner, the valve  64  can be actuated with two different opening functions corresponding to the valve cam  70  and the assistance cams  82 . 
     FIGS. 7 and 8 show an embodiment which, relative to the afore-described embodiment, is only slightly modified. The difference lies in that the electro-magnet  52  of the previously described embodiment is replaced by a hydraulic cylinder  84  so that the blocking bolt  54  for capturing, or respectively, fixedly retaining, the coupling lever  22  is hydraulically actuated. The hydraulic pressure can be directly absorbed by the tolerance compensating device  62 , whereby the hydraulic cylinder  84  can be configured such that it captures the coupling lever  82  at a high hydraulic pressure or at a low hydraulic pressure and fixedly retains the coupling lever, or respectively, releases the coupling lever. It is to be further understood that, as well in this embodiment as in the previously described embodiment, the coupling lever  22  can be configured with a ramp extending to the blocking bolt  54  on which the extended-out blocking bolt  54  is disposed and which thereby captures the coupling lever  22 , if the coupling lever has been moved by the coupling cam  72  in the clockwise direction into its respective position in which the movement translation between the contact roller  48  and the valve actuation bolt  34  has been interrupted. 
     A further embodiment of the inventive apparatus is shown in FIGS. 9-13. This embodiment is distinguished from the previous embodiments in that the coupling bolt  18  is not, as in the previous embodiments, rotatable, but, rather, is displaceably supported in the swing lever arms  12 , and the actuation or switch device  86 , which is configured as an electromagnet or a hydraulic cylinder and secured to the swing arm  10 , is displaced in the direction of the double arrows shown in FIG.  12 . As seen in particular in FIGS. 12 and 13, the coupling bolt  18 , which has two cut-outs  20 , is in its first position, as shown in FIG. 12, whereby, in this position, the coupling bolt is displaced axially such that the cut outs  20  are to the side relative to the contact lever arms  32  of the contact lever  30 , so that the contact lever  30  is in form locking or keyed engagement with the coupling bolt  18  and a swing movement of the contact lever  30  is translated to the swing lever  10 . 
     As seen in FIG. 13, the coupling bolt  18  can be displaced toward the left out of its position as shown in FIG. 12 so that the cut outs  20  are located in the region of the contact lever arms  32  and the contact lever  30  can pass through the coupling bolt  18 , such that a swing movement of the contact lever  30  via the valve cam  70  does not correspondingly take along the swing lever  10 , in which the coupling bolt  18  is supported, and the valve is correspondingly not actuated. 
     It is to be understood that the actuation of the switch unit  86  in accordance with the embodiment shown in FIGS. 9-13 is preferably synchronized with the camshaft rotation such that the switch unit  86 , if the valve is to be placed out of operation, is actuated while the contact roller  48  is in following contact with the base circle of the valve cam  70 . Similarly, the valve in this phase position is again turned off or de-activated. 
     In the embodiment shown in FIGS. 9-13, the camshaft  68  does not support any coupling cams so that this embodiment can be installed on conventional cylinder heads without any modification. 
     The invention can be altered or reconfigured in many ways. In this regard, individual ones of the afore-described features can be combined with one another and/or can additionally be reconfigured. For example, the coupling bolt  18  in the embodiment shown in FIGS. 9-13 can, as well, be rotatable. Furthermore, the bolt  34  need not necessarily or invariably directly actuate the valve; instead, the swing lever can be configured with an additional flange which actuates the valve. Additionally, the configuration of the swing lever can be such that the swing lever simultaneously actuates two valves such as, for example, two inlet valves. The retaining or, respectively, capture, device for the coupling lever  22  can be configured in the form of an electro-magnet which operates to immediately or directly capture the coupling lever  22 , which is configured as an anchor, and so forth. The coupling member can be configured integrally or unitarily with the coupling lever. The cut outs  20  can be replaced through any other embodiment by which a form locking can be achieved and which is releasable. 
     FIG. 14 shows an advantageous detail of the blocking bolt on the appendage on the coupling lever  22  as it is shown, for example, with regard to the embodiment shown in FIGS.  1 - 8 : the appendage  56  of the coupling lever is provided with ribs  88  which can seat in an annular groove  90  formed in the blocking bolt. If the coupling lever  22  is moved by the coupling cam in accordance with FIG. 14 to the rear to the widest possible extent, the blocking bolt  54  is moved toward the right and maintains the coupling lever in a retained position during its subsequently falling forward movement, whereby the blocking bolt is blocked by virtue of the engagement between the ribs  88  and annular groove  90  from making a movement toward the left as shown in FIG.  14 . Correspondingly, the electro-magnet need not be activated to engage the blocking bolt as long as this engagement exists. The engagement releases, in turn, if the coupling lever moves into contact with the apex or radially outermost portion of the coupling cam. An advantage which is achieved with the embodiment according to FIG. 14 is that the signal to the actuator the electro-magnets  52  to lock or release can be given in a wide range and is substantially independent of the angle position of the camshaft. The locking and releasing follows always through a predetermined angular range of the coupling cam. 
     FIG. 15 shows a changed or reconfigured construction of the swing lever, the coupling lever, and the camshaft. In this embodiment, the swing lever is arranged within the contact lever  30 . The rotational support bolt  49 , which rotatably supports the pair of contact rollers  48  each on a side of the contact lever  30 , extends through a large opening of the swing lever  10 . The outer surface region  76  of the swing lever  10 , which cooperates with a cylindrical contact surface  74  of the camshaft  68 , is centrally disposed on the swing lever. The camshaft  68  is correspondingly configured with a cylindrical contact surface  74  and two valve cams  70 . Also, in the embodiment according to FIG. 15, a coupling cam and a corresponding coupling lever can be provided, these components not being shown. The arrangement according to FIG. 15 can, for example, then be advantageous if the free access to the seat of the valve spring in the non-actuated position is very limited. 
     The specification incorporates by reference the disclosure of German priority document 100 60 890.6-13 filed on Dec. 7, 2000. 
     The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.