Abstract:
The present invention provides a variable valve timing device for an internal combustion engine having a double camshaft. A gas exchange valve control shaft is provided which has first and second concentrically arranged cam shafts that are adjustable in a rotatable manner with respect to each other, by which a cam of the first cam shaft is adjusted in terms of its angle towards a cam of the second cam shaft. A cam phasing device is provided which operates by rotatable vanes provoking a swivelling relative movement between a driven member and an output member. The cam phasing device comprises at least two pivotable vane adjusters. Each pivotable vane adjuster is assigned to one of the two cam shafts. The pivotable vane adjusters are arranged axially one after the other in a direction of a valve control shaft. Each pivotable vane adjuster may be designed as a rotor-type vane adjuster.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention refers to a variable valve timing device usable with and for in internal combustion engine. 
       BACKGROUND OF THE INVENTION 
       [0002]    EP 1 347 154 A2 shows a swivel-type adjuster that is designated to be used with a control shaft of a variable valve train. A first hydraulic rotatable mechanism is connected to a second hydraulic rotatable mechanism so that by choosing a raw adjustment and by choosing a fine tuning adjustment an exact position for an eccenter of the variable valve train can be picked. Accordingly, it can be said that the angular position of the eccenter is depicted by a two-stage system. 
         [0003]    U.S. Pat. No. 2,911,956 describes a plate-like shaft positioner by which a swivel movement of a first plate influences the swivel range of a second plate and so forth. 
         [0004]    WO 01/12996 shows in FIG. 5a a two stator vane cam phasing system in which a rotor is limited in its swivel movements by rotating first and second stator. 
         [0005]    Further, by studying U.S. Pat. No. 5,233,948 a person skilled in the art would realize that many advantages can be found by a camshaft with cams that can be superposed. Consequently, for many years there has been a need to design some kind of phase adjuster that can operate such a camshaft. However, practical solutions that actually work in an engine environment can rarely be found. As in U.S. Pat. No. 5,233,948, many basics are only laid open on a theoretical level but there is no teaching how to make them work in practice. 
         [0006]    Attempts how to make such camshafts work can be derived from FIGS. 4a, 4b, 4c of U.S. Pat. No. 5,235. In this document, the figures show a coaxially arranged double camshaft with at least two sets of cams which are offset by an angle. The cams are mounted by fastening pins and fastening clips onto the bearing camshaft. A similar embodiment can be found in WO 2005/040 562 A1. The documents teach a type of hydraulic linear cylinder to select certain positions for the cam. Further, a similar design is shown in FIG. 1 of DE 43 32 868 A1. A further linear adjustable device for camshafts is shown in EP 0 397 540 A1. A different system can be seen in FIGS. 5 and 6 of U.S. Pat. No. 4,332,222 in which a contour bearing pin determines the angle of two cams and by that the position of the camshaft. A document that teaches a very simple and light hollow camshaft is DE 36 24 827. The hollow camshaft taught in that document is, however, outdated in the meantime because nowadays both camshafts have to offer a phase adjustment option. Further reasoning for creating a special contour of a cam can be found in DE 199 14 909 A1, which shows an auxiliary cam for adjusting the contour of the main cam with the purpose to control the gas exchange valves a second time. For reasons of completeness, the two documents JP 11 17 31 20 and WO 1992 012 333 are named. 
         [0007]    From the foregoing prior art, it can be concluded that for years and years the industry has been looking for a workable design which enables the adjusting of the phasing of occurrences in a gas exchange valve train. 
         [0008]    The further graphical representation of a double camshaft can be seen in DE 10 2005 014 680 A1 wherein the graphics stop at the oil distribution bearing. It may be assumed that the Applicant stopped at the point because further components were still needed. The document WO 2005/040562 describes a camshaft with at least two cams. The cams are axially arranged and displaceable. However, the document falls short in teaching how to operate the camshaft in a combustion engine. 
         [0009]    A first sprocket and a second sprocket for a cam phaser attached to a hollow camshaft can be seen in U.S. Pat. No. 6,253,719 B1. Instead of arranging both sprockets in parallel, a different design is shown in U.S. Pat. No. 6,725,817 B2. A first cam phaser that is the inner cam phaser is surrounded by a second cam phaser that is the outer cam phaser. In the meantime, it is known from many different car manufacturers that both types of systems do not work as expected. There is a need to enhance the possible angle of adjustment. 
         [0010]    U.S. Pat. No. 6,076,492 shows that it is widely known that the alignment of a cam phaser, a cylinder head, and a control valve together with a camshaft in a stationary manner is quite difficult. For example, one difficulty can be found by the canting of the components one to the other. 
         [0011]    The described embodiments in the prior art of two offsetable and adjustable gas exchange valve actuation means on one single control shaft have been discussed above to include and incorporate them in the specification in order to enhance the specification and to lead the reader to the more challenging aspects of the present invention. 
         [0012]    A gas exchange valve control shaft comprising two camshafts encroaching each other preferably coaxially arranged with the outer camshaft surrounding the inner camshaft, is also referred to as a double camshaft. A double camshaft is a camshaft which is assembled from two pieces. Persons skilled in the art often associate only one single shaft when hearing a camshaft of which all cams are placed in stationary relationship one to the other. A camshaft within the scope of the present invention is a camshaft of one, two or even more camshafts, especially camshafts having the same axle. 
       SUMMARY OF THE INVENTION 
       [0013]    It is desirable to offer a cam phasing device as part of a variable valve timing device that is applicable to internal combustion engines. Especially with camshafts that comprise adjustable cams for intake and exhaust gas exchange valves on the same camshaft, a cam phaser device may be needed. Advantageously, any kind of camshaft can be operated that has two different sets of cams on the very same camshaft. The device shall be applicable in an automotive environment as an automotive component. 
         [0014]    A variable valve timing device of an internal combustion engine is a device that changes or adapts the relative position of a gas exchange valve actuating component like a cam in respect to a further shaft like a crankshaft. It is widely known to use camshafts for transmitting the actuating impulse. The impulse is applicable on at least one—normally several—gas exchange valves via a control shaft. The control shaft is of a kind that the shaft has at least two concentrically arranged camshafts. The camshafts are adjustable in a rotatable manner with respect to each other. The adjustment is achieved by adjusting a cam of the first camshaft in terms of its angle towards a cam of the second camshaft. To select the position, a cam phasing device is needed. The cam phasing device operates by rotatable vanes provoking a swivelling relative movement between a driven member and an output member. In one embodiment the vanes are profiled. In a further embodiment, the vanes are flat, three-dimensional blocks extending out of a central rotor which can be referred to as rotor cores. Central rotor and vanes are part of a vane adjuster. The cam phasing device comprises at least two pivotable vane adjusters. Each pivotable vane adjuster is assigned to one of the two camshafts. In particular, a first vane adjuster is fixed to a first camshaft and a second vane adjuster is fixed to a second camshaft. The first vane adjuster operates the first camshaft whereas the second vane adjuster operates the second camshaft. The pivotable vane adjusters are arranged axially one after the other in a direction of a valve control shaft. Both vane adjusters are on a common axis. The vane adjusters do not influence each other in their maximum swivel range. The first vane adjuster may still cover its full range while the second vane adjuster has picked any position between its maximum advanced and its maximum retarded position. With this design, the position of a first a camshaft does not influence the selectability of a position for the second camshaft still occupying the same elongated space. 
         [0015]    The variable valve timing device further comprises rotor type vane adjusters in that each pivotable vane adjuster is designed in a rotor-type manner. Each rotor type vane adjuster can be changed in respect of its phase by hydraulic pressure in two sets of hydraulic chambers. The phase is measured in respect of a further shaft like the camshaft. The two sets of hydraulic chambers form counter moving chambers to each other. The pivotable vane adjusters each constitute an output member of one of the cam-shafts. Each output member comprises a vane rim. The vane rims are attached to rotor cores being movable between a first position and a second position limited by division bars of a surrounding stator housing. By using the design of vane type cam phasers—which are known to a certain extent by themselves—a very fast and very responsive adjuster can be created. 
         [0016]    The variable valve timing device has a double camshaft. The gas exchange valve control shaft is a coaxially arranged double camshaft. Of that double camshaft the first camshaft is formed as an hollow body and in the hollow body the second camshaft is aligned and placed in a manner so that through at least one recess a cam of the second camshaft pokes out to an outside of the first camshaft. The double camshaft is very efficient in terms of space. It occupies very little additional space outside of the camshaft as is necessary and advantageous in internal combustion engines. 
         [0017]    The variable valve timing device has only one drive pulley. The drive pulley is exposed to a driving means like a chain or a belt. The cam phasing device has only one drive pulley such as a sprocket adapted to be driven by a chain which can surround a crankshaft of the internal combustion engine. The variable valve timing device has a side which is a near side of the camshaft, and the variable valve timing device has a side which is a far side from the camshaft. The variable valve timing device is planar. The variable valve timing device has a communication collar on the near side. The near side bears conduits for intake and piping of a hydraulic fluid to each of the sets of chambers of the first and said second pivotable vane adjuster. The communication collar moves synchronously along with the drive pulley. The integration of hydraulic conduits for the first and second vane adjuster contributes to the compactness of the variable valve timing device. The same applies to using only one drive pulley. 
         [0018]    The variable valve timing device has at least four conduits. Two of the four conduits are located in the vicinity of an axis of the camshaft which channel fluid from the communication collar to the pivotable vane adjuster. They conduct hydraulic fluid like engine oil to the vane adjuster which is located farther away from the communication collar than the second pivotable vane adjuster. The two of the four conduits are located remotely to the axis of the camshaft channel from the communication collar to the second pivotable vane adjuster. The second vane adjuster is located nearer to the communication collar. In a very dense circular cross section all conduits necessary for operation can be placed in the rotor core and the core of the variable valve timing device. 
         [0019]    In a further advantageous embodiment, the variable valve timing device bears an oil distribution adapter. The oil distribution adapter is centered in the cam phasing device. The cam phasing device is penetrated by at least four longitudinal fluid passages. In one embodiment, each one of the fluid passages is of a different length. The fluid passages open out into one of the sets of hydraulic chambers. This alternative design in respect of oil distribution can be easily manufactured while being still very reliable. 
         [0020]    The variable valve timing device has at least two output members. One of the output members is located farther away from the gas exchange valve control shaft and operates the camshaft which is an inner camshaft in comparison to the second camshaft. One of the output members is located nearer to the gas exchange valve control shaft and operates the camshaft which is an outer camshaft and encloses the inner camshaft. The output member which is farther away is screwed to the inner camshaft whereas the output member which is located nearer to the gas exchange valve control shaft is shrink fitted on the outer camshaft. The type of fixation is a fast and reliable method for fixing the vane adjusters to the camshafts. 
         [0021]    The variable valve timing device has four hydraulic ports. The four hydraulic ports are placed in the communication collar. The ports form channels from a stationary part such as a cylinder head of the internal combustion engine to each set of hydraulic chambers of each pivotable vane adjuster so that the communication collar forms part of a bearing ring. By this means, the hydraulic fluid is tuneable in each channel. Each vane adjuster can take up a desirable position independent from the other vane adjuster. 
         [0022]    The variable valve timing device has a spring. The spring can be a coil spring. The spring can be designed as an inlay in the driven member. The spring props on one side against the pulley and pushes one of the pivotable vane adjusters in a pre-selected state. Preferably, the intake valves take on a pre-selected position in case of emergency or uncontrolled hydraulic pressure. As a result, the internal combustion engine may be operated even when the hydraulic circuit does not work as anticipated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The present invention will hereinafter be described in conjunction with the appended drawing figures, wherein like reference numerals denote like elements, and: 
           [0024]      FIG. 1  shows an opened cam phasing device in accordance with a first example embodiment of the present invention, 
           [0025]      FIG. 2  shows an example cam phasing device along the line A-A of  FIG. 1 , 
           [0026]      FIG. 3  shows an example cam phasing device of  FIG. 1  along the line B-B of  FIG. 2 , 
           [0027]      FIG. 4  shows an example cam phasing device of  FIG. 1  along the line C-C of  FIG. 2 , 
           [0028]      FIG. 5  shows an example cam phasing device of  FIG. 1  along the line D-D of  FIG. 2 , 
           [0029]      FIG. 6  shows an example cam phasing device of  FIG. 1  along the line E-E of  FIG. 2 , 
           [0030]      FIG. 7  shows an example cam phasing device of  FIG. 1  along a further line F-F of  FIG. 1  around a locking pin, 
           [0031]      FIG. 8  shows a further example embodiment of the present invention in schematic view, and 
           [0032]      FIG. 9  shows a further example embodiment of the present invention in schematic view. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    The ensuing detailed description provides exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the ensuing detailed description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing an embodiment of the invention. It should be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth in the appended claims. 
         [0034]      FIG. 1  shows a cam phasing device  1  which operates as a rotatable vane phasing device. The rotatable vane phasing device can swivel within a certain range of angle φ freely from one side to a second side. The rotation is caused and provoked by oil out of fluid passages  20 ,  21 ,  22 ,  23  by which counter-acting chambers  67 ,  68  (refer to  FIG. 4 ) are loaded. The cam phasing device  1  can be designed as a double-cam phasing device if driven by one single drive wheel  43 . In the example shown, the drive wheel  43  is a sprocket  44 . Sprockets  44  stand out by a reduced slipping. The outer cover of the cam phasing device  1  serves as one consistent drive torso  46 . In its center, the cam phasing device  1  is arranged with at least two output members  62 ,  63  (refer to  FIGS. 4 and 6 ) setup on the same axis. Centrally, a vane rim  64  which is underneath the shown signal plate  37  is placed two times exactly identically adjacent one next to the other in the cam phasing device  1 . 
         [0035]      FIG. 2  shows the inner construction of a cam phasing device  1  in a sectional view along the line A-A of  FIG. 1 . It can be seen that the cam phasing device  1  is a layered phasing device whereas in its inner part two rotors  4 ,  5  are located. The inner rotor  5  is placed closer to the camshafts  16 ,  18  which form one unified camshaft. The camshafts  16 ,  18  pass through the exact same camshaft bearing  17  which bears the inner centrally placed camshaft  18  by the outer camshaft  16 . The rotors  4 ,  5  are separated by a center plate  7 . Components  4 ,  5 ,  7  of the cam phasing device  1  are arranged in layers and span between the front plate  2  and the back plate  9 . The center plate  7  separates as one piece the rotors  4 ,  5 . Center plate  7  and the stators  6 ,  8  are arranged stationarily in a rototable manner. The front plate  2  is centered by a spindle  3  for the camshafts  16 ,  18  to be attached to. An oil distribution adapter  19  with numerous channels ensures the oil distribution towards the chambers of the cam phasing device  1 . The oil distribution adapter  19  has at least four supply channels  20 ,  21 ,  22 ,  23 . As it can be seen in  FIGS. 3 to 6 , the fluid passages lead into at least four passages  24 ,  25 ,  26 ,  27 . The camshafts  16 ,  18  are guided by at least one common retainer  14 . The camshafts  16 ,  18  are circumscribed by at least one journal  15 . The cam phasing device  1  is attached to the camshaft by an adapter  11 . All the components  2 ,  6 ,  7 ,  8 ,  9  of the cam phasing device  1  can be braced by at least one screw  10  such as a countersunk screw  12  and can be screwed in a stationary manner. Both rotors  4 ,  5  can rotate relatively to the braced components from a first bar  65  to a second bar  66  (refer to  FIG. 3 ). At least one of rotors  4 ,  5 , very often the rotor that is attached to the intake camshaft, is pushed by a spring  13  which can be a spiral spring, into a predetermined position, especially if the chambers  67 ,  68  are without oil or without pressure. The camshafts  16 ,  18  are part of the valve train  100 . Facing the camshaft device  1  is an inflow  33  for a hydraulic fluid so that parallel to the camshaft axis  38  a hydraulic fluid can be provided to each rotor  4 ,  5 . 
         [0036]    In  FIG. 2 , four lines B-B, C-C, D-D, E-E are marked which can be seen in further details in  FIGS. 3 to 6 , respectively. The lines B-B and C-C pass through the first rotor  4  and the lines D-D and E-E pass through the second rotor  5 . In the drawings  3  to  6 , the oil supply is realized by at least four parallelly extended fluid passages  20 ,  21 ,  22 ,  23  following the valve train axis whereas each channel opens out into a passage annulus  24 ,  25 ,  26 ,  27 . Both rotors  4 ,  5  have a similar swivel range. The swivel range is determined by the angle of the bars  65 ,  66 . Each rotor  4 ,  5  has at least a first chamber  67  and a second chamber  68 . Several chambers of the same type—if existing several times—form one set  69  of first chambers and a second set  70  of second chambers in each area of the cam phasing device. The oil supply is delivered in this respect for all four systems of chambers via the center  71  of the cam phasing device  1 . Each rotor  4 ,  5  (refer to  FIG. 2 ) forms an output member  62 ,  63  (refer to  FIGS. 4 ,  6 ) for a camshaft  16 ,  18 . The output members  62 ,  63  are beaded along one common axis  38  of the camshaft. In at least one of the rotors  4 ,  5  a locking pin  34  for locking the rotor  4  to the stator  6  while being in a special state of operation can be inserted. In this respect, in one drive torso  46  there are a first and a second rotor  4 ,  5 . On the vane rim  64  which is located centrally, rotor vanes extend outwardly. 
         [0037]    One example embodiment of a locking mechanism comprising the components locking pin  34 , lock spring  35 , and spring plate  36  is shown in  FIG. 7 . Of course, several locking pins can be placed in one rotor  4 ,  5 . 
         [0038]    The cam phasing device  1  in accordance with  FIG. 2  receives the hydraulic media like oil via one face. The input place, the inflow  33  for the oil, is located in the oil distribution adapter  19 . 
         [0039]    A further example embodiment in accordance with the invention can be seen in  FIG. 8 , which shows a cam phasing device  1  designed as a double cam phasing device of the swivel type. For better presentability the individual components like stator housing  45 , camshafts  16 ,  18  and rotors  4 ,  5  are drawn with a certain distance in between whereas the components can be produced by casting, embossing or rolling. Each rotor can reach within its swivel range every position independently from the other rotor. Both rotors  4 ,  5  are uncoupled. They are placed in the same stator housing  45 . The stator housing  45  is one single piece—as graphically shown—which is coherent and comprises several chambers. The housing  45  can be produced, as an example only, as a casting component. Certain areas of the stator housing  45  can be designated by front plate  2 , first stator  6 , center plate  7  and second stator  8 . The areas  2 ,  6 ,  7  and  8  are cohesive. In a further alternative embodiment certain areas like the first stator  6  and the second stator  8  can be separated one from the other while being joinable. In this respect, the same component can be reproduced and joined two times. In the spaces between the first rotor  4  and the first stator  6  chambers  67  are formed. Likewise chambers  68  are shaped between the second stator  8  and the second rotor  5 . In each rotor  4 ,  5  at least two passages  24 ,  25 ,  26 ,  27  are drilled. Along the oil distribution adapter  19 , which can be comprised of several components and with multiple channels, the hydraulic media flows in at least four hydraulic pressure systems towards chambers which are placed at the end of the channels. The hydraulic media is under pressure P when provided to one of the chambers  67 ,  68  for provoking a swivel movement. The hydraulic pressure system is symbolized by the letters A 1 , B 1 , A 2 , B 2 . The hydraulic separation of the hydraulic systems is secured by sealings  49  which are in-line adjacent one after the other represented schematically. The outer rotor  4  extends through its middle towards the camshaft  18  while being circumscribed by the inner rotor  5 . The inner camshaft  18  is circumscribed by the outer camshaft  16 . The rearward outer rotor  4  can be mounted in one advantageous embodiment by a retainer  14  to the camshaft  18  (as shown in  FIG. 8 ). To protect the stator housing  45 , a lid  47  of the cam phasing device  1  can be mantled to cover the inner part of the cam phasing device  1 . The lid  47  opens out into the drive wheel  43  which is formed to meet with the driving belt surface to surface. The drive wheel  43  is part of the back plate  9 . A spring  13  is inlaid in the back plate  9  which presses at least one of the rotors  4 ,  5  in an advantageous position. The receiving space for the spring  13  is located between the rear plate  9  and the adapter  11 . The rear adapter  11  takes care of an easy mounting of the rotor  5  onto the outer camshaft  16 . The rotor  5  is screwed to the first journal  15  by a countersunk screw  12 . The rotor  5  has a smaller volume than the second rotor  4  arranged in parallel. For the mounting, normally several countersunk screws  12  are placed in a through-hole drilling from one of the rotors  4 ,  5 . The screwing keeps the components tensioned. Pass-throughs of the screws  12  can be sealed by sealing sleeves  48 . In  FIG. 8  the cam phasing device  1  is only shown by its upper part in a schematic representation. A capable designer will be able to use the given instructions to create a double cam phasing device in accordance with the present invention which can be produced in industries. 
         [0040]    A further advantageous example embodiment of a cam phasing device  1  with two camshafts  16 ,  18  in accordance with the invention can be seen in  FIG. 9 . In  FIG. 9 , one can see in a schematic representation the mounting or arrangement of the (double) cam phasing device  1  with (double) camshaft  101  having at least two different sets of cams  103 ,  104 . The double camshaft  101  comprises both camshafts  16 ,  18  which are placed coaxially. One of the sets of the cams  103  is fastened to the outer camshaft  16  while the second set of cams  104  is mounted to the inner camshaft  18  in a relative stationary position. By a swivel movement of one camshaft  16  to the second camshaft  18  the central control shaft  102  varies the opening and closing times of the gas exchange valves. The cam phasing device  1  has a near side  41  and a far side  42  to the camshaft. On the near side  41  is the drive torso  46  especially in the form of a sprocket  44 . The cam phasing device  1  has an axial arrangement  40  of the individual layers  60 ,  61 . A connection collar  32  encloses the double designed camshaft  101  at the end for offering an inflow of the hydraulic fluid for adjusting a phasing of the layers  60 ,  61 . The connection collar  32  has several ports  28 ,  29 ,  30 ,  31  (e.g., at least four different ports  28 ,  29 ,  30 ,  31 ), all of which can be used as oil hand-over places. The first camshaft  16  has at least one recess  105  through which a cam  104  reaches to the outside of the double camshaft  101 . The swivel movement of each layer  60 ,  61  will be transmitted directly and without conversion to one of the camshafts  16 ,  18  and by this the same swivel angle can be seen on the cams  103 ,  104 . For this, all components are arranged along one single axis  38  of the camshaft  101 . The rotors extend in a normal direction  39  from the camshaft axis  38 . 
         [0041]    Although only three example embodiments of the present invention have been described in detail, it should be apparent to someone skilled in the art that the described embodiments can only be understood as examples that do not impose any limitation on the scope of the invention and how to realize the invention. 
         [0042]    Consequently, the scope of the invention also includes the usage of more than just two individual rotors. The scope of the invention also covers a cam phasing device with and without additional adapters between camshafts and cam phasing device. The drive torso can be actuated by a crank shaft, by a belt, by meshing gears, and by an electric motor. 
         [0043]    The present invention has many advantages. Only one single device is needed to operate and actuate two shafts. This contributes to the reduction in size and package. One component can be handled more easily and can be attached to the concentric camshaft easier than all devices known up to now. 
         [0044]    In addition, by using two parallel plans for the rotors, the dual camshaft phaser, also called cam phasing device  1 , is able to drive the dual concentric camshaft. The dual phaser consists of two individual phasers stacked at the end of the concentric camshafts  16 ,  18 . The individual phasers drive the separate camshafts in the dual concentric camshafts. The two phasers are using common designed stators  6 ,  8  and rotors  4 ,  5  with a shared center plate  7 . The stacked stators  6 ,  8  and rotors  4 ,  5  are sandwiched inside the sprocket with back plate  9  and the front plate  2 . Screws  10  pass through the sprocket with back plate  9 , back stator  8 , center plate  7 , front stator  6 , and front plate  2 , holding them together as a single stacked assembly. 
         [0045]    A spindle  3  is attached to the front rotor  4  and reaches through the back rotor  5  to drive the center shaft  18  of the dual concentric camshaft  101 . The spindle  3  has fluid passages  20 ,  21 ,  22 ,  23  to feed hydraulic fluid (oil) through. These passages can also feed from the rear of the phaser through the camshaft  101 . The oil is supplied from the engine oil system by two control valves (not shown in the figures). One of the control valves controls the oil feed  20 ,  21  to the front rotor  4 . This oil moves through the passages  24 ,  25  of the rotor  4  to either side of the vanes to rotate the center shaft  18  to the desired position. The position is infinite within a set value between 30 to 70 degrees (usually around 50 degrees) of the crankshaft rotational position. 
         [0046]    The rear rotor  5  is attached to the rear adapter  11 , which drives the outside shaft  16  of the dual concentric camshaft, which is attached through first journal  15 . A second control valve controls oil feed through passages  22 ,  23  in the area of the spindle  3  that reaches through the rear rotor  5 . The oil moves through passages  26 ,  27  to either side of the vanes of the rear rotor  5  to rotate the outer shaft  16  to a desired position. The position is infinite within a set value between 30 to 70 degrees (usually around 50 degrees) of the crankshaft rotational position. 
         [0047]    At engine startup both rotors  4 ,  5  can be locked (in an alternative example embodiment) in a determined position when the rotors  4 ,  5  are in the locked position with the lock pins  34 . The lock pins are held in place by the lock spring  35  and spring plate  36 . As the engine starts and the control valves feed the oil pressure to disengage the lock pins  34  the rotors are free to move. 
         [0048]    Although the invention has been described in connection with various illustrated embodiments, numerous modifications and adaptations may be made thereto without departing from the spirit and scope of the invention as set forth in the claims. 
       REFERENCE LIST 
       [0049]      
         [0000]    
       
         
               
               
               
             
           
               
                   
               
               
                 Reference 
                   
                   
               
               
                 Numeral 
                 Significance 
                 Drawing 
               
               
                   
               
             
             
               
                  1 
                 Cam phasing device 
                 FIG. 1, FIG. 2, FIG. 8, 
               
               
                   
                   
                 FIG. 9 
               
               
                  2 
                 Front plate 
                 FIG. 2, FIG. 8 
               
               
                  3 
                 Spindle 
                 FIG. 2 
               
               
                  4 
                 First rotor or front rotor 
                 FIG. 2, FIG. 7, FIG. 8, 
               
               
                   
                   
                 FIG. 9 
               
               
                  5 
                 Second rotor or back rotor 
                 FIG. 2, FIG. 8, FIG. 9 
               
               
                  6 
                 First stator or front stator 
                 FIG. 2, FIG. 8 
               
               
                  7 
                 Center plate, especially as shared 
                 FIG. 2, FIG. 8 
               
               
                   
                 center plate 
               
               
                  8 
                 Second stator or back stator 
                 FIG. 2, FIG. 8 
               
               
                  9 
                 Back plate 
                 FIG. 2, FIG. 8 
               
               
                 10 
                 Screw 
                 FIG. 2 
               
               
                 11 
                 Rear adapter 
                 FIG. 2, FIG. 8 
               
               
                 12 
                 Countersunk screw 
                 FIG. 2, FIG. 8 
               
               
                 13 
                 Recoil spring 
                 FIG. 2, FIG. 8 
               
               
                 14 
                 Retainer 
                 FIG. 2, FIG. 8 
               
               
                 15 
                 First journal 
                 FIG. 2, FIG. 8 
               
               
                 16 
                 Outside shaft 
                 FIG. 2, FIG. 8, FIG. 9 
               
               
                 17 
                 Camshaft bearing 
                 FIG. 2 
               
               
                 18 
                 Second camshaft as a center shaft 
                 FIG. 2, FIG. 8, FIG. 9 
               
               
                 19 
                 Oil distribution adapter 
                 FIG. 2, FIG. 8 
               
               
                 20 
                 First fluid passage 
                 FIG. 1, FIG. 2, FIG. 3 
               
               
                 21 
                 Second fluid passage 
                 FIG. 1, FIG. 2, FIG. 4 
               
               
                 22 
                 Third fluid passage 
                 FIG. 1, FIG. 2, FIG. 5 
               
               
                 23 
                 Fourth fluid passage 
                 FIG. 1, FIG. 2, FIG. 6 
               
               
                 24 
                 First passage 
                 FIG. 3, FIG. 8 
               
               
                 25 
                 Second passage 
                 FIG. 4, FIG. 8 
               
               
                 26 
                 Third passage 
                 FIG. 5, FIG. 8 
               
               
                 27 
                 Fourth passage 
                 FIG. 6, FIG. 8 
               
               
                 28 
                 First port 
                 FIG. 9 
               
               
                 29 
                 Second port 
                 FIG. 9 
               
               
                 30 
                 Third port 
                 FIG. 9 
               
               
                 31 
                 Fourth port 
                 FIG. 9 
               
               
                 32 
                 Communication collar 
                 FIG. 9 
               
               
                 33 
                 Inflow for the hydraulic medium 
                 FIG. 2 
               
               
                 34 
                 Lock pin 
                 FIG. 4, FIG. 7 
               
               
                 35 
                 Lock spring 
                 FIG. 7 
               
               
                 36 
                 Spring plate 
                 FIG. 7 
               
               
                 37 
                 Signal plate 
                 FIG. 1 
               
               
                 38 
                 Axis of the camshaft 
                 FIG. 2, FIG. 9 
               
               
                 39 
                 Perpendicular on the axis of the 
                 FIG. 9 
               
               
                   
                 camshaft 
               
               
                 40 
                 Axial arrangement, especially in 
                 FIG. 8, FIG. 9 
               
               
                   
                 respect of the camshaft 
               
               
                 41 
                 Near side to the camshaft 
                 FIG. 9 
               
               
                 42 
                 Far side from the camshaft 
                 FIG. 9 
               
               
                 43 
                 Drive wheel 
                 FIG. 1, FIG. 8 
               
               
                 44 
                 Sprocket 
                 FIG. 1, FIG. 9 
               
               
                 45 
                 Stator housing 
                 FIG. 8, FIG. 9 
               
               
                 46 
                 Drive torso 
                 FIG. 1, FIG. 4, FIG. 8, 
               
               
                   
                   
                 FIG. 9 
               
               
                 47 
                 Lid of the cam phasing device 
                 FIG. 8 
               
               
                 48 
                 Sealing sleeve 
                 FIG. 8 
               
               
                 49 
                 Sealing 
                 FIG. 8 
               
               
                 60 
                 First layer of a cam phasing device 
                 FIG. 9 
               
               
                 61 
                 Second layer of a cam phasing device 
                 FIG. 9 
               
               
                 62 
                 First output member 
                 FIG. 4 
               
               
                 63 
                 Second output member 
                 FIG. 6 
               
               
                 64 
                 Vane rim 
                 FIG. 1, FIG. 3 
               
               
                 65 
                 First bar 
                 FIG. 3 
               
               
                 66 
                 Second bar 
                 FIG. 3 
               
               
                 67 
                 First chamber 
                 FIG. 4, FIG. 8 
               
               
                 68 
                 Second chamber 
                 FIG. 4, FIG. 8 
               
               
                 69 
                 First set of chambers 
                 FIG. 3 
               
               
                 70 
                 Second set of chambers 
                 FIG. 3 
               
               
                 71 
                 Center of the cam phasing device 
                 FIG. 5 
               
               
                 100  
                 Valve train 
                 FIG. 2 
               
               
                 101  
                 Camshaft, especially double camshaft 
                 FIG. 9 
               
               
                 102  
                 Gas exchange valve control shaft 
                 FIG. 9 
               
               
                 103  
                 Cam of the first type 
                 FIG. 9 
               
               
                 104  
                 Cam of the second type 
                 FIG. 9 
               
               
                 105  
                 Clearance of the first camshaft, 
                 FIG. 9 
               
               
                   
                 especially for reach-through of a cam 
               
               
                 A-A 
                 Section 
                 FIG. 1 
               
               
                 B-B 
                 Section 
                 FIG. 2, FIG. 3 
               
               
                 C-C 
                 Section 
                 FIG. 2, FIG. 4 
               
               
                 D-D 
                 Section 
                 FIG. 2, FIG. 5 
               
               
                 E-E 
                 Section 
                 FIG. 2, FIG. 6 
               
               
                 F-F 
                 Section 
                 FIG. 7 
               
               
                 A1 
                 Oil channel system for the first set of 
                 FIG. 8 
               
               
                   
                 chambers 
               
               
                 B1 
                 Oil channel system for the first set of 
                 FIG. 8 
               
               
                   
                 chambers 
               
               
                 A2 
                 Oil channel system for the first set of 
                 FIG. 8 
               
               
                   
                 chambers 
               
               
                 B2 
                 Oil channel system for the first set of 
                 FIG. 8 
               
               
                   
                 chambers 
               
               
                 P 
                 Hydraulic media under pressure 
                 FIG. 8 
               
               
                 φ 
                 Angle of rotation 
                 FIG. 1