Abstract:
Mechanical controls for continuously varying the length of the stroke of the valves in an internal-combustion engine and for maintaining the valves constantly closed while the engine is in operation while simultaneously varying how long the valve or valves remain open, whereby the valves are actuated by rocker levers that are in turn actuated by an angled lever, whereby the positions of the levers are varied in order to vary the length and duration of the stroke. 
     The valves are actuated at low engine speeds by assigning a specific narrow angle of rotation to each abbreviated stroke to be established. 
     FIG.  1  illustrates valve stroke controls with an angled lever ( 2 ) actuated by a cam ( 17 ) mounted on a lateral roller ( 3 ). In the event of a misalignment, a planetary gear comes into play, wherein a roller ( 9 ), mounted on the rocker lever ( 8 ) that actuates the valve ( 1 ) acts a sun wheel, the angled lever ( 2 ) acts as a planet wheel, and a setting lever ( 5 ) acts as a planet bearing.

Description:
BACKGROUND OF THE INVENTION 
   The present invention concerns mechanical controls that, during the operation of an internal combustion engine continuously vary the strokes of individual valves and groups of valves from maximally open to constantly closed, while simultaneously varying how long the valve or valves remain open. The valves are actuated by rocker levers that are in turn driven by subsidiary rocker levers, or by tilting or angled levers. The particular positioning of the subsidiary rocker. tilting, or angled levers dictates the length and duration of the stroke. With the exception of one set, the valve-stroke controls allow actuation of the valves in the lower engine speed ranges. In accordance with manufacturers&#39; specifications, once a shorter stroke has been selected, a considerably more acute angle of rotation for the open range of the valves and an angle even more acute in relation to the angle of rotation associated with valve opening will be available for the procedure of opening and closing the valves. 
   SUMMARY OF THE INVENTION 
   With the exception of further valve-stroke controls, only a little shift in the valve actuation phasing, if any, occurs. 
   These controls cam be employed for controlling valves without throttling and for valve-and-cylinder turnoff. 
   Furthermore, valves can be alternately actuated with these controls by using different cams, the shift resulting from the adjustment of control levers and without using switchover coupling bolts. Accessories can be employed to extend maintenance intervals. 
   These controls feature characteristics of the controls disclosed in patent application Ser. No. 100 36 373.3-13, the priority of which is hereby claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a sectional view of one embodiment of valve-stroke controls with an angled lever, according to the present invention; 
       FIG. 2  is a sectional view of another embodiment of valve-stroke controls with an angled lever; 
       FIG. 3  is a sectional view of a further embodiment of valve-stroke controls with an angled lever; 
       FIG. 4  is a sectional view of one embodiment of valve-stroke controls with two rocker levers; 
       FIG. 5  is a sectional view of another embodiment of valve-stroke controls; 
       FIG. 6  is a sectional view of another embodiment of FIG.  4 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  illustrates valve-stroke controls with an angled lever, actuated by a lateral roller, whereby adjustment involves the action of a planetary gear with rollers on the rocker lever that actuates the valves acting on a sun wheel, the angled lever acting as a planet wheel, and the setting lever acting as a planet carrier. 
     FIG. 2  illustrates valve-stroke controls with an angled lever laterally actuated by a cam that, by way of rollers fastened to an adjustable articulated rod, drives rocker levers that actuate valves. 
     FIG. 3  illustrates valve-stroke controls with an angled lever driven by a lateral cam that is articulated to a setting lever such that the lever will execute the motion of a tilting lever, deiving a rocker lever that actuates a valve. 
     FIG. 4  illustrates valve-stroke controls with two rocker levers, one on each side of a setting lever and each being driven by a cam and driving a rocker lever that actuates a valve. 
     FIG. 5  illustrates valve-stroke controls wherein the cammed roller is fastened to a horizontal steering lever, preventing a phase shift in valve actuation while the controls are being adjusted. 
     FIG. 1  illustrates valve-stroke controls accommodated in a cylinder head for the purpose of actuating a valve  1 . A more or less upright angled lever  2  driven by a revolving cam  3  mounted at one edge. One angled-lever setting lever  5  is mounted on each side of angled lever  2  and acts as an accommodation for the swivel  4  that angled lever is mounted in. Angled lever  2  is provided with two structures  6  and  7  that project downward at more or less of a right angle to the longitudinal axis of angled lever  2 . Structure  6  actuates a rocker lever that actuates valve  1  by way of a roller  9 . Structure  7  on the other hand maintains the valve constantly closed. 
   These valve-stroke controls continuously vary the stroke of the valve from maximally open to constantly closed, while the engine is in operation, but the duration decreases with the length of the stroke. Only a slight phase shift of the valve actuation is possible. 
   The valve-stroke controls in accordance with the present invention operate on the same principle as a planetary gear, a roller  9  on the swiveling gear representing the sun wheel ad angled lever  3  exercising the function of planet wheel. 
   Structure  7  has a positively circular curvature and constitutes the roll-over surface of a planet wheel. Angled-levers setting levers  5  act as planet mounts and are provided with a swivel  11  that swivels on cylinder head  10  around the same axis as the “sun” roller  9  on rocker lever  8  as long as valve  1  remains closed. When angled-lever setting levers  5  pivot, accordingly, angled-lever  2  pivots along the circumference of a circle around swivel  11  and hence around the shaft of rollers  9 . When, on the other hand, angled lever  2  pivots, valve  1  is not actuated and its “play” is unaffected as long as the circular structure  7  engages the circumference of roller  9 . In this situation, the distance L between the common axis of rotation of lower swivel  4  on levers  5  and rollers  9  and the one and the axis of rotation of the upper common swivel  4  on levers  5  and angled lever  2  on the other will be the total of radius R 1  of curvature of structure  7  and the radius R 2  of roller  9 : L=R 1 +R 2  when, subsequent to an adjustment on the part of setting levers  5 , negative structure  6  engages the circumference of roller  9 , rocker lever  8  will initially be actuated with only a brief rocking motion around an acute angle of rotation, whereby, as the structure continues to engage the circumference of the roller, the rocking motion and angle of the rocking lever will increase. 
   For purposes of adjustment, setting lever or setting levers  5  are provided with a contour in the form of an arc of a circle provided with cogs and extending around the axis of rotation of swivel  11 , which is engaged by a driveshaft  13  with matching cogs. The two setting levers, however, can also be driven by an articulated rod subject to an eccentric shaft or crankshaft. 
   In State A, the controls are set for maximal valve stroke and, in State B, to maintain valves  1  closed. Two valves can be actuated simultaneously, and two angled levers  2  can be employed, one on each side of a setting lever  5 , every angled lever driving a rocker lever that actuates a valve  1 . 
   The end of the rocker lever  8  that actuates a valve  1  is provided with a valve-play compensator  14 , its upward motion limited by an appropriately positioned adjustable counterbearing  15 . Counterbearing  15  is fastened to the cylinder head and provided with a dashpot. The position of counterbearing  15  allows the controls to function normally even when the upper surface of valve  1  is hit by a valve head and raised. In this event, counterbearing  15  will maintain the engagement between angled lever  4  and the roller  9  on rocker lever  8  unaffected, whereby any displacement of valve  1  will be compensated by compensator  14 . 
   Since cams  17  can drive angled lever  2  in only one direction, it must be driven in the opposite direction by a resetting component  18  that forces roller  3  against cams  17 . 
     FIG. 2  illustrates valve-stroke controls accommodated in a cylinder head and intended for the simultaneous actuation of two valves  19 . Each of the two rocker levers  20  is driven by a single roller  21  at the top. Rollers  21  are mounted on the same axis  17 . Axis  22  is secured to the fork uprights of a longitudinally variable articulated rod  23 . Another roller  21  rotates between the others and between the fork uprights. 
   A more or less upright angled lever  24  is positioned above middle roller  21  and laterally driven by a cam  28  mounted on a roller  29 . The upper end of angled lever rotates on a swivel  25  integrated into the cylinder head. The lower end of the lever is provided with structures  26  and  27  that extend at more or less a right angle to its longitudinal axis and engage middle roller  21 . Structure  26  is responsible for maintaining valve  19  constantly closed and its contour is in the form of a positive circular arc. 
   The radius R of the arc exhibits a center located in the axis of rotation of swivel  25 . Adjacent to structure  26 , structure  27 , in the form of a negative curve, is responsible for generating a valve stroke. Articulated rod  23  is accommodated in a swivel  30  in a setting lever  31  driven by a driveshaft  32 , and the controls are adjusted by displacing articulated rod  23  over structures  26  and  27 . 
   These controls make it possible to continuously vary the length of the valve stroke while the engine is in operation from a maximum to constantly closed, whereby the time during which the valve remains open decreases with the length of the stroke. 
   There is no phase shift. 
   At angular State A, the valve-stroke controls are set for maximal stroke and, at State B, for maintaining valves  19  constantly closed. 
   When only one valve  19  is to be actuated, angled lever  24  drives middle roller  21 , while rocker lever  20  is simultaneously driven by the outer rollers  21 . The middle roller has a shorter diameter, preventing torque on articulated rod  23 . It is alternatively possible for the two outer rollers  21  to be driven by angled levers  24 , with the middle roller driven by angled lever  24  (sic). 
   Cams  28  can drive angled lever  24  in one direction, and it is driven in the other direction by a resetting mechanism  33  that forces the lever and its roller  29  against cam  28 . Resetting mechanism  33  is fastened to angled lever  24  by a swivel  34  and at a swivel  35  to a lever  36  connected to setting lever  31  such that, when the controls are adjusted for a shorter stroke, the restoring force of resetting mechanism  33  will simultaneously increase. 
     FIG. 3  illustrates valve-stroke controls accommodated in a cylinder head and intended for actuating a valve  37 . A more or less upright angled lever  38  is driven at the top by a cam  40  mounted on a lateral roller  34 . There is a setting lever  41  on each side of angled lever  38 , acting as an accommodation for a swivel  42  in angled lever  38 . Swivel  42  is located at the bottom of lever  38 . Setting lever  41  rotates along with a driveshaft  43  in the cylinder head. 
   The angled lever  38  in accordance with the present invention operates on the principle of a tilting lever, whereby, however, the lever, in order to actuate a valve  37 , is provided with structures  42  and  45  that extend down at more or less a right angle to its longitudinal axis, with structure  44  driving a rocker lever  46  by way of its roller  47 . Engagement on the part of structure  45  with roller  47  on the other hand maintains valve  37  constantly closed. Structure  47  is in the form of a positively circular arc, its radius R being provided with a center along the axis of rotation of angled lever  38 . 
   These valve-stroke controls can continuously vary the length of a stroke from maximum to constantly closed while the engine is in operation, whereby the length of time the valve remains open decreases with the length of the stroke. 
   The phase shift is only slight. 
   In State A, the controls are adjusted for maximal stroke length and, in State B, for maintaining valve  31  constantly closed. 
   Cam  40  can drive angled lever  38  in only one direction, and it must be driven in the other direction by a resetting mechanism  48  that forces angled lever  38  and its roller  38  against cam  40 . Resetting mechanism  38  is connected on the one hand to angled lever  38  by a swivel and on the other accommodated in the swivel  49  common to the two setting levers  41 . 
     FIG. 4  illustrates valve-stroke controls accommodated in a cylinder head and intended for actuating two valves  51  simultaneously. The controls in accordance with the present invention are provided with a setting disk  52  that rotates in a bearing block  54  fastened to a cylinder head  53 . Bearing block  54  also acts on a bearing for accommodating a camshaft  55  and a driveshaft  56  and as a holder for recuperating springs  51 . Setting disk  52  has an axis  58  at one side. On each side of the setting disk is a rocker lever  59 . Each rocker lever  59  is driven by a separate cam  61  mounted on a roller at the top. Rocker levers  59  are provided with downward directed structures  62  and  63  that more or less parallel the longitudinal axis of rocker lever  59 . Each structure  62  drives a rocker lever  64  by way of its roller  65 , whereas structures  63  maintain valves  61  constantly closed. 
   These valve-stroke controls can continuously vary the length of a stroke between a maximum and constant closure. The duration that a valve is open decreases with the valve stroke. The valve actuation is subject to phase shift, the replacement of one camshaft adjustment mechanism if the camshaft is rotating in the right sense. 
   These controls operate on the principle of a planetary gear, the rollers  65  associated with the two valves executing the function of a sun wheel, rocker lever  64  that of a planetary wheel, and the positively circular arc the rollover edge of a planet wheel. Setting disk  52  acts as a planet carrier, its axis of rotation simultaneously being the axis of rotation of the rollers that act as a sun wheel when valves  51  are closed. Thus, as setting disk  52  turns, rocker lever  59 , mounted on axis  58 , will move in a circle around the axis common roller  65  and setting disk  52 , whereby during the rocking motion of rocker lever  59 , valves  51  will not be actuated, and the valve play will remain unaffected as long as positively circular structure  63  engages the circumference of roller  65 . Structures  63 , which maintain valves  51  constantly closed, are in the form of positive circular arcs with a radius R 1 . The center of the circle is along the axis of rocker lever  59 . Radius R 1  plus the Radius R 2  of rollers  65  are as long as the distance L between the common axis of setting disk  52  and rollers  65  on the one hand and the axis  58  of setting disk  52 . Once setting disk  52  has turned and negative structures  62  have come into engagement with the circumference of rollers  65 , rocker lever will be driven, initially around an acute angle, whereas, on the other hand, as the structures continue to engage the rollers, the rocking motion will increase along the angle. 
   The circumference of setting disk  52  is provided with cogs  66  that extend along it in a circle. These cogs are engaged by the cogs around the driveshaft that rotate in bearing block  54 . 
   In State A, the controls are set for maximal stroke and, in State B for constantly closed valves  52 . 
   One valve  51  or three valves  52  simultaneously can be actuated by two setting disks  52 . A rocker lever  59  driven by a cam  61  is mounted between the setting disks  52  on an axis  58  that extends between the setting disks. To actuate three valves  51  simultaneously, another rocker lever  59  driven by a cam  61  is mounted outside setting disks  52  on an axis  58  extending out of the disks. All rocker levers  59  actuate their valves  51  by way of their associated rocker levers  64 . 
   Since cams  61  drive rocker levers  59  in only one direction, they must be shifted in the other direction by recuperators in the form of rotary springs  57  that force rocker levers  59  and its associated roller  60  against cams  61 . 
   The shanks of the springs, to simplify their installation and assembly, are inserted into and clamped in the impact range of the divided bearing for camshaft  55  in bearing block  54 . 
   Due to rocker levers  58 , adjacent and oppositely oriented on various axes  58  of setting disks  52 , valves  51  can be actuated by different cams  61 . Rocker levers  59  are mounted on setting disk  52  on at least two axes  58  such that a rotation on the part of the setting disk group of rocker lever  59  pointing in one sense of rotation will move into the range of engagement with the cams, whereas another group, pointing in the other direction, will simultaneously move out of the range. 
     FIG. 5  illustrates valve-stroke controls accommodated in a cylinder head and intended for actuating a valve  67 . Resetting of the controls does not result in any valve-actuation phase shift. The controls in accordance with the present invention are provided with a cammed roller  69  mounted on a more or less horizontal driving rod  68 . Driving rod  68  rotates sround a control shaft  70 . Below and paralleling driving rod  68  is a rocker lever  71 . Rocker lever  71  is mounted at one end in a swivel  72  that is part of a setting lever  73  that rotates along with control shaft  70 . At its other end, rocker lever  71  is mounted in a swivel  74  in a predominantly perpendicular articulated rod  75  connected to the axis of cammed roller  69 . Below rocker lever  71  is another rocker lever  78  that is provided with a roller  77 . Upwards, roller  77  engages a structure  78  in the form of a negative circular arc on rocker lever  71 . The distance L between the axis of rotation of roller  69  and that of swivel  74  equals the distance between the axis of rotation of control shaft  70  and that of swivel  72 . The radius R 1  of the downward facing structure  78  on rocker lever  71  equals the distance L plus the radius R 2  of the roller  77  on rocker lever  76 —R 1 =L*R 2 . 
   Since cam  79  can be driven in only one direction, driving rod  68  and rocker lever  71  plus articulated rod  75  must be driven in the opposite direction by a resetting component  80 . Resetting component  80  is connected to the cylinder head at one end and, at the other, by way of a swivel  81  that is part of a lever  82  connected to driving rod  68 , forcing roller  69  against cam  79 . 
   The controls illustrated in  FIG. 4  also make it possible to employ as a setting component a setting lever  83  as represented in  FIG. 6  instead of the setting disk  52  hereintofore specified. The axis of rotation of setting lever  83  must, as with setting disk  52 , align with the axis of rotation of roller  65  when its associated valve  51  is closed. Setting lever  83  can be in the form of an angled lever, in which case it will be provided with, remote from its axis of rotation, an axially parallel pivoting accommodation with an axis  58  for a rocker lever  59 . In this event, setting lever  83  will perform the function of setting disk  52 . 
   Either setting disk  52  or setting lever  83  can be mounted on one side, or, overlapping the controls, on both sides. Setting lever  83  can be turned indirectly by way of a control shaft  56  as depicted in  FIG. 6  or directly.