AND RELATED METHOD

FIELD

[0001] The present disclosure relates to a timing system for operating an engine valve system and a related method.

BACKGROUND

[0002] This section provides background information related to the present disclosure which is not necessarily prior art.

[0003] PCT Publication No. WO/2018/013464 discloses an engine valve system having cams with multiple profiles that can be selectively positioned along the rotational axis of a shaft so that a desired one of the profiles on the cams is used to operate the valves of the engine. One drawback associated with such engine valve systems is the timing system that coordinates movement of the cams. Such timing systems typically require two or more solenoid-controlled plungers that interact with that helical tracks to initiate movement of the cams and possibly to maintain the cams in a desired location along the rotational axis of the shaft. Coordination of the movement of the plungers is controlled electronically and must occur at relatively high speeds to ensure intended operation of the engine valve system.

[0004] Accordingly, there remains a need in the art for a less complex timing system for coordinating the movement of cams along the rotational axis of a shaft.

SUMMARY

[0005] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0006] In one form, the present disclosure provides a timing system for operating an engine valve train. The timing system includes a shaft, a first cam member, and an actuator assembly. The shaft is rotatable about a shaft axis. The first cam member is non-rotatably but axially slidably coupled to the shaft and has a first cam configuration and a second cam configuration. The first cam configuration has a first predetermined lift profile, while the second cam configuration has a second predetermined lift profile that is different from the first predetermined lift profile. The first cam member is slidable along the shaft axis between a first cam member position, in which the first cam configuration is positioned in an activated location along the shaft and the second cam configuration is displaced along the shaft from the activated location, and a second cam member position in which the second cam configuration is positioned in the activated location along the shaft and the first cam configuration is displaced along the shaft from the activated location. The actuator assembly has a first actuator cam, a first linkage, a first follower, and a second follower. The first actuator cam is non-rotatably but axially slidably coupled to the shaft. The first linkage couples the first actuator cam to the first cam member for common movement along the shaft axis. Placement of the first actuator cam along the shaft in a first actuator cam position correspondingly positions the first cam member in the first cam member position. Placement of the first actuator cam along the shaft in a second actuator cam position correspondingly positions the first cam member in the second cam member position. The first actuator cam defines a first shift cam and a second shift cam. Each of the first and second followers is rotatable about a rotary follower axis that is disposed parallel to the shaft axis between at least one inactive position and an active position. The first follower does not interact with the first shift cam or the second shift cam to affect a position of the first actuator cam along the shaft when the first follower is disposed in the at least one inactive position. The second follower does not interact with the first shift cam or the second shift cam to affect a position of the first actuator cam along the shaft when the second follower is disposed in the at least one inactive position. The first follower is configured to interact with the first shift cam to shift the first actuator cam along the shaft from the second actuator cam position to the first actuator cam position when the first follower is in the active position. The second follower is configured to interact with the second shift cam to shift the first actuator cam along the shaft from the first actuator cam position to the second actuator cam position when the second follower is in the active position.

[0007] In another form, the present disclosure provides a method for operating a timing system that is configured to operate an engine valve train. The timing system has a shaft, which is rotatable about a shaft axis, a first cam member and an actuator assembly. The first cam member is non-rotatably but axially slidably coupled to the shaft. The first cam member has a first cam configuration and a second cam configuration. The first cam configuration has a first predetermined lift profile, while the second cam configuration having a second predetermined lift profile that is different from the first predetermined lift profile. The first cam member is slidable along the shaft axis between a first cam member position, in which the first cam configuration is positioned in an activated location along the shaft and the second cam configuration is displaced along the shaft from the activated location, and a second cam member position in which the second cam configuration is positioned in the activated location along the shaft and the first cam configuration is displaced along the shaft from the activated location. The actuator assembly has a first actuator cam, a first linkage, a first follower, and a second follower. The first actuator cam is non-rotatably but axially slidably coupled to the shaft. The first linkage couples the first actuator cam to the first cam member for common movement along the shaft axis. Placement of the first actuator cam along the shaft in a first actuator cam position correspondingly positions the first cam member in the first cam member position. Placement of the first actuator cam along the shaft in a second actuator cam position correspondingly positions the first cam member in the second cam member position. The first actuator cam defines a first shift cam and a second shift cam. The method includes: mounting the first and second followers so that they are rotatable about a rotary follower axis that is disposed parallel to the shaft axis; rotating the second follower into an inactive position where it does not interact with the first shift cam or the second shift cam to effect a position of the first actuator cam along the shaft; rotating the first follower into an active position to cause the first follower to interact with the first shift cam to drive the first actuator cam from the second actuator cam position to the first actuator cam position to thereby move the first cam member from the second cam member position to the first cam member position; rotating the first follower into an inactive position where it does not interact with the first shift cam or the second shift cam to effect a position of the first actuator cam along the shaft; and rotating the second follower into an active position to cause the second follower to interact with the second shift cam to drive the first actuator cam from the first actuator cam position to the second actuator cam position to thereby move the first cam member from the first cam member position to the second cam member position.

[0008] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. DRAWINGS

[0009] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0010] Figure 1 is a perspective view of an exemplary timing system constructed in accordance with the teachings of the present disclosure, the timing system being illustrated in operative association with a cylinder head and a set of valves;

[0011] Figure 2 is an exploded perspective view of the timing system of Figure 1 ;

[0012] Figure 3 is a longitudinal cross-sectional view of a portion of the timing system of Figure 1 illustrating a shaft, a plurality of cam structures and a portion of an actuator assembly in more detail;

[0013] Figure 4 is a portion of a longitudinal cross-section of a portion of the timing system of Figure 1 illustrating the shaft, one of the cam structures and a portion of the actuator assembly in more detail;

[0014] Figure 5 is a perspective view of a portion of the timing system of Figure

1 ;

[0015] Figure 6 is an enlarged portion of Figure 2;

[0016] Figure 7 is a side elevation view of a portion of the timing system of Figure 1 illustrating portions of the actuator assembly in more detail;

[0017] Figure 8 is a perspective view of a portion of the timing system of Figure 1 illustrating the shaft, a pair of cam actuators, first and second followers, and first through fourth timing members in more detail, the second follower having a follower member in an active position that interacts with the cam actuators;

[0018] Figure 9 is front elevation view of the portion of the timing system depicted in Figure 8, with the follower member of the second follower in the active position;

[0019] Figure 10 is a side elevation view similar to that of Figure 7 but depicting the follower members of the first and second followers in inactive positions and one of the first timing members in a change-over position;

[0020] Figure 11 is a perspective view similar to Figure 8 but depicting the follower members of the first and second followers in inactive positions and one of the first timing members in a change-over position;

[0021] Figures 12, 13 and 14 are views similar to Figure 10 but depicting the first timing member causing rotation of the second timing members and the first and second followers so that one of the follower members of the first follower is rotated into an active position; and

[0022] Figures 15 through 19 are perspective views of the portion of the timing system depicted in Figure 8, but illustrating the follower member of the second follower that is in the active position coordinate the movement of the actuator cams from a second cam member position to a first cam member position.

[0023] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

[0024] Although the terms first, second, third, etc. may be used herein to describe various elements, components and/or positions, these elements, components and/or positions should not be limited by these terms. These terms may be only used to distinguish one element, component or position from another element, component or position. Terms such as“first,”“second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a“first” element, component or position discussed below could be termed a“second” element, component or position without departing from the teachings of the example embodiments.

[0025] With reference to Figures 1 and 2 of the drawings, a timing system constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 10. The timing system 10 can include a shaft 12, one or more cam structures 14, and an actuator assembly 16.

[0026] The shaft 12 can be mounted to a suitable structure, such as a cylinder head 20 or a cylinder block of an internal combustion engine, for rotation about a shaft axis 26. The shaft 12 can be a hollow, tubular structure having a longitudinally extending shaft aperture 30, one or more toothed or male splined segments 32, a plurality of link grooves 34, and an actuator mount 36. In the example provided, the male splined segments 32 are disposed about the exterior circumference of the shaft 12 and are spaced apart along the shaft axis 26. Each of the link grooves 34 can be formed through a wall of the shaft 12 and can extend parallel to the shaft axis 26. In the example provided, each of the link grooves 34 is disposed between a pair of the male splined segments 32. The actuator mount 36 can comprise one or more slots 40 that are formed through the wall of the shaft 12. In the particular example shown, the actuator mount 36 comprises two slots 40 that are disposed diametrically opposite one another.

[0027] Each of the cam structures 14 can have a female toothed or splined aperture 50, one or more cam members, which have a plurality of cam configurations, and a link aperture 52. In the example provided, each of the cam structures 14 has first and second cam members 54 and 56, respectively, that are fixedly coupled to one another. Each of the first cam members 54 can have first and second cam configurations 60 and 62, respectively, that are spaced apart from one another along the longitudinal axis (which is coincident with the shaft axis 26) of the female splined aperture 50. The first cam configuration 60 can have a first predefined lift profile, while the second cam configurations 62 can have a second predefined lift profile that is different from the first predefined lift profile. The first and second lift profiles can differ from one another in their magnitude of maximum lift, the relative angular positioning of their maximum lift, the duration of their maximum lift, and/or the rate or manner at which the lift profile varies between base circle and the point at which maximum lift is attained, for example.

[0028] Similarly, the second cam members 56 can have third and fourth cam configurations 64 and 66, respectively, that are spaced apart from one another along the longitudinal axis of the female splined aperture 50. The third cam configuration 64 can have a third predefined lift profile, while the fourth cam configuration 66 can have a fourth predefined lift profile that is different from the third predefined lift profile. The third and fourth lift profiles can differ from one another in their magnitude of maximum lift, the relative angular positioning of their maximum lift, the duration of their maximum lift, and/or the rate or manner at which the lift profile varies between base circle and the point at which maximum lift is attained, for example. Each of the link apertures 52 can be formed through the wall of an associated one of the cam structures 14. The cam structures 14 can be received onto the shaft 12 such that the teeth of the female splined aperture 50 axially slidably but non-rotatably engage the teeth of the male splined segments 32 and the link apertures 52 are aligned to the link slots 40.

[0029] With reference to Figure 3, the cam structures 14 are movable along the shaft axis 26 between a first cam member position (shown below the shaft axis 26) and a second cam member position (shown above the shaft axis 26). Placement of the cam structures 14 in the first cam member position locates the first and second cam members 54 and 56 along the shaft axis 26 so that the first and third cam configurations 60 and 64, respectively, are in activated locations A in which the first and third cam configurations 60 and 64 are employed to operate respective sets of engine valves (not shown) and the second and fourth cam configurations 62 and 66 are displaced from the activate location and do not affect the operation of the respective sets of engine valves. Placement of the cam structures 14 in the second cam member position locates the first and second cam members 54 and 56 along the shaft axis 26 so that the second and fourth cam configurations 62 and 66, respectively, are in the activated location so that the second and fourth cam configurations 62 and 66 are employed to operate the respective sets of engine valves, while the first and third cam configurations 60 and 64 are displaced from the activate location and do not affect the operation of the respective sets of engine valves.

[0030] Returning to Figures 2 and 4, the actuator assembly 16 can include one or more links 80, one or more actuator cams 82, a first follower 84, a second follower 86, a first timing member 88, a second timing member 90, a third timing member 92, a fourth timing member 94 and an activation motor 98.

[0031] In the example provided, four cam structures 14 are provided, with two of the cam structures 14 being mounted to each of the links 80. It will be appreciated, however, that the number of links 80 and the number of cam structures 14 could be different from that which is specifically described herein and shown in the drawings. Each of the links 80 can have a link member 100 and one or more connecting members 102 that can be fixedly coupled to the link member 100.

[0032] The link members 100 can be received in the shaft aperture 30 in the shaft 12 and can be coupled (e.g., fixedly coupled) to an associated one of the actuator cams 82 for movement therewith along the shaft axis 26. The link members 100 extend radially outwardly from their associated link member 100 through a corresponding one of the link slots 40 and into a corresponding one of the link apertures 52 to thereby couple the cam structures 14 to the links 80 for movement therewith along the shaft axis 26. In this regard, sliding movement of the links 80 along the shaft axis 26 will cause corresponding sliding motion of the cam structures 14 on the shaft 12 along the shaft axis 26. The connecting members 102 can be non-removably coupled to their respective link members 100 (e.g., unitarily and integrally formed therewith, or welded thereto), or assembled to their respective link members 100 in a permanent manner (e.g., riveted) or a removable manner (e.g., threaded fastener). [0033] With reference to Figures 5 and 6, two actuator cams 82 are employed in the example illustrated, with each of the actuator cams 82 and each of the actuator cams 82 can have a generally C-shaped body structure 120, a guide member 122, a first shift cam 124 and a second shift cam 126. The body structure 120 can define a shaft recess 130 that is configured to fit about the shaft 12 in the vicinity of the actuator mount 36. The guide member 122 can extend in a radially inward direction from the body structure 120 and can be configured to be received into an associated one of the slots 40 in the actuator mount 36. It will be appreciated that the configuration of the actuator cams 82, including the shaft recess 130 and the guide member 122, and the actuator mount 36, including the slots 40, permits the actuator cams 82 to be axially slidably but non-rotatably mounted to the shaft 12 between a first actuator cam position (shown below the shaft axis 26 in Figure 3) and a second actuator cam position (shown above the shaft axis 26 in Figure 3).

[0034] The first and second shift cams 124 and 126 can extend about the exterior circumference of the body structure 120 and can be opposite sidewalls of a common groove 140. It will be appreciated, however, that each of the first and second shift cams 124 and 126 could be formed by discrete grooves. The first shift cam 124 can define a first cam portion 150, which extends circumferentially (i.e. , such that the first cam portion 150 lies in a first plane that is perpendicular to the shaft axis 26), a second cam portion 152, which extends circumferentially (i.e., such that the second cam portion 152 lies in a second plane that is perpendicular to the shaft axis 26), and a first transition portion 154 that spirals about the shaft axis 26 to connect the first and second cam portions 150 and 152. The first and second cam portions 150 and 152 (i.e., the first and second planes) are spaced axially apart along the shaft axis 26 by an amount that is required to shift the cam structures 14 to change between the different pairs of cam configurations.

[0035] Similarly, the second shift cam 126 can define a third cam portion 170, which extends circumferentially (i.e., such that the third cam portion 170 lies in a third plane that is perpendicular to the shaft axis 26), a fourth cam portion 172, which extends circumferentially (i.e., such that the fourth cam portion 172 lies in a fourth plane that is perpendicular to the shaft axis 26), and a second transition portion 174 that spirals about the shaft axis 26 to connect the third and fourth cam portions 170 and 172. The third and fourth cam portions 170 and 172 (i.e., the third and fourth planes) are spaced axially apart along the shaft axis 26 by an amount that is required to shift the cam structures 14 to change between the different pairs of cam configurations.

[0036] The first and second followers 84 and 86 can be non-rotatably coupled to a follower shaft 200. The follower shaft 200 can be supported (e.g., via the cylinder head) for rotation about a follower axis 202 that is parallel to the shaft axis 26. Each of the first and second followers 84 and 86 can have a follower body 210 and a pair of diametrically opposed follower members 212 that extend radially outwardly from the follower body 210. Each of the first and second followers 84 and 86 can be rotated about the follower axis 202 between inactive positions, in which the follower members 212 do not interact with the actuator cams 82, and active positions in which the follower members 212 interact with the actuator cams 82. The follower members 212 of the first follower 84 are positioned along the follower axis 202 so that when either one of them is positioned in an active position, the follower member 212 cooperates with the first shift cams 124 to cause sliding movement of the actuator cams 82 along the shaft axis 26 from the second actuator cam position to the first actuator cam position. The follower members 212 of the second follower 86 are rotated ninety degrees about the follower axis 202 from the follower members 212 of the first follower 84. The follower members 212 of the second follower 86 are positioned along the follower axis 202 so that when either one of them is positioned in an active position, the follower member 212 cooperates with the second shift cams 126 to cause sliding movement of the actuator cams 82 along the shaft axis 26 from the first actuator cam position to the second actuator cam position. While the first and second followers 84 and 86 are shown and described herein as being separate structures, it will be appreciated that the first and second followers 84 and 86 could be integrally and unitarily formed.

[0037] The first and second timing members 88 and 90 are configured to coordinate the rotation of the first follower 84 about the follower axis 202 from one of the inactive positions to one of the active positions. The first timing member 88 can be rotatably coupled to an associated one of the actuator cams 82, while the second timing member(s) 90 can be rotatably coupled to the first follower 84. In the particular example provided, the first timing member 88 is unitarily and integrally formed with one of the actuator cams 82, while two of the second timing members 90 are unitarily and integrally formed into a washer-like structure that is coupled to the follower shaft 200 for common rotation. It will be appreciated that the first timing member 88 could be formed as a discrete component that could be coupled to the one of the actuator cams 82 for common rotation, and/or that the second timing member(s) 90 could be unitarily and integrally formed with the first follower 84.

[0038] In Figures 6 and 7, the first timing member 88 can be a tooth-like structure that is formed on an associated one of the actuator cams 82. More specifically, the tooth-like structure can be formed at the intersection of a radially extending surface and a circumferentially extending surface on the associated one of the actuator cams 82. The second timing members 90 can be teeth that can extend radially from an annular timing member body 250. The timing member body 250 can be formed with relief portions 252 that are configured to prevent contact between the timing member body 250 and the actuator cams 82 as the actuator cams 82 rotate about the shaft axis 26. For example, the relief portions 252 can be aligned about the follower axis 202 to the angular orientations of the follower members 212 of the first and second followers 84 and 86. The second timing members 90 can be positioned about the follower axis 202 into a change-over position in which one of the second timing members 90 is disposed in a rotational path of the first follower member 212. Contact between the first follower member 212 and one of the second timing members 90 as the shaft 12 rotates in a predetermined rotational direction will cause rotation of the second timing members 90 about the follower axis 202 in a rotational direction that positions one of the relief portions 252 about the actuator cams 82 so that neither the actuator cams 82 nor the first follower member 212 interact with the second timing members 90 or the timing member body 250. Because the second timing members 90 are rotationally coupled to the first follower 84, this rotation of the second timing member 90 (caused by meshing engagement of the first timing member 88 with one of the second timing members 90) also drives one of the follower members 212 of the first follower into an active position where it can interact with the first shift cam 124.

[0039] The third timing member 92 can be a tooth-like structure that is formed on an associated one of the actuator cams 82. More specifically, the tooth-like structure can be formed at the intersection of a radially extending surface and a circumferentially extending surface on the associated one of the actuator cams 82. The fourth timing members 94 can be teeth that can extend radially from an annular timing member body 270. The timing member body 270 can be formed with relief portions 272 that are configured to prevent contact between the timing member body 270 and the actuator cams 82 as the actuator cams 82 rotate about the shaft axis 26. The fourth timing members 94 can be positioned about the follower axis 202 into a change-over position in which one of the fourth timing members 94 is disposed in a rotational path of the third follower member 212. Contact between the third follower member 212 and one of the fourth timing members 94 as the shaft 12 rotates in a predetermined rotational direction will cause rotation of the fourth timing members 94 about the follower axis 202 in a rotational direction that positions one of the relief portions 272 about the actuator cams 82 so that neither the actuator cams 82 nor the third follower member 212 interact with the fourth timing members 94 or the timing member body 270. Because the fourth timing members 94 are rotationally coupled to the second follower 86, this rotation of the fourth timing member 94 (caused by meshing engagement of the third timing member 92 with one of the fourth timing members 94) also drives one of the follower members 212 of the second follower 86 into an active position where it can interact with the second shift cam 126.

[0040] Returning to Figure 1 , the activation motor 98 can be any type of motor for rotating the first and second followers 84 and 86 and the second and fourth timing members 90 and 94 about the follower axis 202. For example, the activation motor 98 could be a rotary motor having an output shaft (not shown) that is drivingly coupled to the follower shaft 200, either directly or through a transmission, and with or without a mechanism that provides intermittent rotary output motion, such as a Geneva mechanism. Alternatively, the activation motor 98 can comprise a linear motor, such as a solenoid or fluid-powered cylinder, and a mechanism that converts the reciprocating motion of the output member of the linear motor into a rotating motion, such as a Scotch yoke mechanism, a crank slider mechanism.

[0041] With reference to Figures 3, 8 and 9, the cam structures 14 can be disposed in the second cam member position during the operation of the internal combustion engine such that one of the follower members 212 of the second follower 86 is received in the grooves 140 in the actuator cams 82 and the first and second cam members 54 and 56 are positioned along the shaft axis 26 such that the second and fourth cam configurations 62 and 66 are disposed in their activated locations A (and are thus positioned to operate their respective sets of engine valves). In this condition, the follower members 212 of the first follower 84 are disposed outside the grooves 140 in the actuator cams 82 and the timing member bodies 250 and 270 of the second and fourth timing members 90 and 94 are disposed about the follower axis 202 such that the relief portions 252 and 272 are aligned to the actuator cams 82 so that neither the first follower 84 nor any of the first and second timing members 88 and 90 or the timing member bodies 250 and 270 have any effect on the positioning of the actuator cams 82 along the shaft axis 26.

[0042] With reference to Figures 10 and 11 , the activation motor 98 (Fig. 1 ) can be operated to rotate the second timing members 90 about the follower axis 202 to position one of the second timing members 90 in the rotational path of the first timing member 88 (i.e. , in a change-over position). Rotation of the second timing members 90 into this position also causes corresponding rotation of the first and second followers 84 and 86 and the fourth timing members 94 about the follower axis 202. This places one of the follower members 212a of the first follower 84 in a still inactive but transitional position, both of the follower members 212 of the second follower 86 in inactive positions, the third timing member 92 and the timing member body 270 in positions where they have no effect on the positioning of the actuator cams 82 along the shaft axis 26.

[0043] With reference to Figures 12 through 15, contact between the first timing member 88 and the one of the second timing members 90 as the first timing member 88 rotates in the predetermined direction causes cogging or rotation of the second timing members 90 about the follower axis 202 through a predetermined angle of rotation that is sufficient to position the one of the follower members 212a of the first follower 84 (i.e., the one of the follower members 212 previously in the transition position) in an active position and within the groove 140 in the actuator cams 82, as well as to disengage the one of the second timing members 90 from the first timing member 88. At this point, neither of the second timing members 90 will be in the rotational path of the first timing member 88, neither of the fourth timing members 94 (Fig. 11 ) will be in the rotational path of the third timing member 92 (Fig. 10), relief portions 252 and 272 (Fig. 11 ) on the timing member bodies 250 and 270 (Fig. 11 ) will be aligned to the actuator cams 82, and the follower members 212 of the second follower 86 will be in inactive positions.

[0044] With reference to Figures 3 and 15 through 19, continued rotation of the shaft 12 and the actuator cams 82 will cause contact between the first slide cam 124 and the follower member 212 of the first follower 84 that is disposed in the active position. The contact between the first slide cam 124 and the follower member 212 of the first follower 84 will drive the actuator cams 82 along the shaft axis 26 to cause corresponding movement of the cam structures 14 to position the first and third cam configurations 60 and 64 in their activated locations so that they are positioned to operate their respective sets of engine valves. The one of the follower members 212 of the first follower 84 can be maintained in its activated position if desired to ensure that the cam structures 14 do not move along the shaft axis 26 and the first and third cam configurations 60 and 64 remain in their activated positions.

[0045] Returning to Figures 8 through 11 , the activation motor 98 (Fig. 1 ) can be operated to rotate the fourth timing members 94 about the follower axis 202 to position one of the fourth timing members 94 in the rotational path of the third timing member 92 (i.e, a change-over position). Rotation of the fourth timing members 94 into this position also causes corresponding rotation of the first and second followers 84 and 86 and the second timing members 90 about the follower axis 202. This places one of the follower members 212 of the second follower 86 in a still inactive but transitional position, both of the follower members 212 of the first follower 84 in inactive positions, and the first timing member 88 (and the timing member body 250) in positions where they have no effect on the positioning of the actuator cams 82 along the shaft axis 26.

[0046] Contact between the third timing member 92 and the one of the fourth timing members 94 as the third timing member 92 rotates in the predetermined direction causes cogging or rotation of the fourth timing members 94 about the follower axis 202 through a predetermined angle of rotation that is sufficient to position the one of the follower members 212 of the second follower 86 (i.e., the one of the follower members 212 previously in the transition position) in an active position and within the groove 140 in the actuator cams 82, as well as to disengage the one of the fourth timing members 94 from the third timing member 92. At this point, neither of the second timing members 90 will be in the rotational path of the first timing member 88, neither of the fourth timing members 94 will be in the rotational path of the third timing member 92, relief portions 252 and 272 on the timing member bodies 250 and 270 will be aligned to the actuator cams 82, and the follower members 212 of the first follower 84 will be in inactive positions.

[0047] Continued rotation of the shaft 12 and the actuator cams 82 will cause contact between the second slide cam 126 and the follower member 212 of the second follower 86 that is disposed in the active position. The contact between the second slide cam 126 and the follower member 212 of the second follower 86 will drive the actuator cams 82 along the shaft axis 26 to cause corresponding movement of the cam structures 14 to position the second and fourth cam configurations 62 and 66 in their activated locations so that they are positioned to operate their respective sets of engine valves. The one of the follower members 212 of the second follower 86 can be maintained in its activated position if desired to ensure that the cam structures 14 do not move along the shaft axis 26 and the second and fourth cam configurations 62 and 66 remain in their activated positions.

[0048] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.