CN111441839A

CN111441839A - Sliding camshaft assembly

Info

Publication number: CN111441839A
Application number: CN202010046046.2A
Authority: CN
Inventors: H.W.阮; D.切尔托; B.R.卡安; J.J.穆恩
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2019-01-17
Filing date: 2020-01-16
Publication date: 2020-07-24
Also published as: DE102019133661A1; US20200232348A1

Abstract

A camshaft assembly includes an actuator and an axially movable structure mounted to a base shaft, wherein the axially movable structure includes a plurality of lobe sets and a cam barrel. The axially movable structure moves along the base shaft in an axial direction along the longitudinal axis of the base shaft, but is rotationally fixed to the base shaft. The cam barrel includes an inner wall and an outer wall defining a control groove therebetween. The control groove defines a first region comprising a fixed narrow control groove width and a second region comprising a gradually decreasing control groove width. An actuator displaces the axially movable structure relative to the base shaft between a first position and a second position. A recess is defined in the outer wall such that the recess is disposed adjacent the first region.

Description

Sliding camshaft assembly

Technical Field

The present disclosure relates to a sliding camshaft for a vehicle engine.

Background

In modern internal combustion engines, variable valve actuators can be used to set different valve strokes at the gas exchange valves of the internal combustion engine in order to optimize the charge movement in the combustion chamber. The axial displacement of the cams results in different valve strokes being set at the respective gas exchange valves. A conventional valve drive comprises a sliding cam which is mounted on a camshaft in a rotationally fixed but axially displaceable manner, wherein the sliding cam can also comprise a cam cylinder with a plurality of grooves, and wherein, in order to bring about an axial displacement of the sliding cam, an actuator with a plurality of pins which can be activated is provided. The cam barrel may have a first right-hand groove and a second left-hand groove which are arranged side by side with each other on the circumference of the cam barrel and merge with a common run-out groove. The pins of the actuator interact with the grooves of the cam barrel.

Further, a valve actuator is known in which grooves of a cam cylinder are provided one after another on the circumference of the cam cylinder, specifically, a first groove for axial displacement of a slide cam in a first direction and a second groove for axial displacement of the slide cam in an opposite second direction. In the valve drive, the actuator further has a plurality of actuatable pins to cause axial displacement of the sliding cam, specifically a first pin for axially displacing the sliding cam in both directions about the first axial segment, and a second pin for axially displacing the sliding cam in both directions about the second axial segment.

In order to carry out engine control of an internal combustion engine having such a valve drive with at least one displaceable sliding cam, the relative position of the sliding cam on the camshaft and thus the relative position of the cam lobe with respect to the gas exchange valves of the internal combustion engine to be activated must be known. Hitherto, it has been difficult to detect the relative position of the sliding cam on the camshaft in a reliable manner, and therefore the relative position of the cam track with respect to the gas exchange valves to be activated has not been detected.

Disclosure of Invention

In one embodiment of the present disclosure, a camshaft assembly is provided, wherein the camshaft assembly includes an actuator and an axially moveable structure mounted to a base shaft, wherein the axially moveable structure includes a plurality of lobe sets and a cam barrel. The axially movable structure moves along the base shaft in an axial direction along the longitudinal axis of the base shaft, but is rotationally fixed to the base shaft. The cam barrel includes an inner wall and an outer wall defining a control groove therebetween. The control groove further includes a first region and a second region, wherein the second region defines a fixed narrow control groove width and the first region defines a gradually changing control groove width. An actuator displaces the axially movable structure relative to the base shaft between a first position and a second position. A recess is defined in the outer wall of the cartridge such that the recess is disposed adjacent the second region of the control groove.

The camshaft assembly may also include a sensor configured to align with the axially moveable structure along the first sensor path when the axially moveable structure is moved to the first position. The aforementioned sensor may also be configured to align with the axially moveable structure along the second sensor path when the axially moveable structure is moved to the second position. The first sensor path covers the outer wall and a recess defined in the outer wall. The second sensor path covers the control recess and the outer wall. However, it is understood that the recess is disposed outside of the second sensor path. Accordingly, the aforementioned camshaft assembly of the present disclosure may also include an engine control module in communication with the actuator and the sensor.

The recess and the outer wall may be configured to communicate with an engine control module via a sensor to detect/confirm a first position of the axially moveable structure when the recess and the outer wall are aligned with the sensor in the first sensor path. The sensor is configured to send a feedback signal (in the form of a first data set) to the engine control module based on a configuration of the cam barrel along the first sensor path. More specifically, the recess and the outer wall are configured to communicate with an engine control module via a sensor to detect/confirm a first position of the axially moveable structure when the recess and the outer wall are aligned with the sensor in a first sensor path.

Similarly, the control recess and outer wall may also be configured to communicate with the engine control module via the sensor to detect/confirm the second position of the axially moveable structure when the control recess and outer wall are aligned with the sensor in the second sensor path. The sensor is configured to send a feedback signal (in the form of a second data set) to the engine control module based on a configuration of the cam barrel along the second sensor path.

Each of the plurality of lobe sets includes a first cam lobe adjacent to a second cam lobe in the axial direction. The first cam lobe is configured to engage an engine valve when the axially moveable structure is in the first position. Similarly, the second cam lobe is configured to engage the engine valve when the axially moveable structure is in the second position.

In yet another embodiment of the present disclosure, an engine assembly includes an engine control module, an internal combustion engine, a camshaft assembly, an actuator, and a sensor. An internal combustion engine includes a first cylinder, a second cylinder, a first valve operatively coupled to the first cylinder, and a second valve operatively coupled to the second cylinder. The camshaft assembly may be coupled to first and second valves of an internal combustion engine. The camshaft assembly also includes a base shaft and an axially movable structure mounted on the base shaft. The base shaft may extend along a longitudinal axis and be configured to rotate about the longitudinal axis. The axially movable structure is configured to move between a first position and a second position on the base shaft, but the axially movable structure is rotationally fixed to the base shaft. The aforementioned axially movable structure includes a cam barrel having a control groove defined between an inner wall and an outer wall of the cam barrel. The control groove may define a fixed narrow groove width throughout the second region and a gradually changing enlarged groove width in at least a portion of the first region of the cam barrel.

The actuator is configured to move the axially movable structure between the first position and the second position via a pin of the actuator engaging a control groove in the cam barrel in accordance with an output signal from an engine control module. The sensor is configured to send a first data set (feedback signal) to the engine control module when the axially moveable structure is in the first position. The sensor is further configured to send a second data set (feedback signal) to the engine control module when the axially moveable structure is in the second position. It will be appreciated that a recess is defined in the outer wall of the cam barrel and is aligned with the sensor when the axially moveable structure is in the first position.

With respect to the aforementioned engine assembly, the enlarged groove width of the first region may be greater than the fixed narrow groove width of the second region. As noted, the actuator may include at least one pin configured to move between a retracted position and an extended position (where the pin engages the control recess) in response to an output signal from the engine control module. Further, the axially moveable structure may also include a plurality of lobe sets configured to rotate synchronously with the cam barrel as the axially moveable structure rotates with the base shaft. Each of the plurality of lobe sets includes a first cam lobe adjacent to a second cam lobe. The first cam lobe has a first maximum lobe height, the second cam lobe has a second maximum lobe height, and the first maximum lobe height is different than the second maximum lobe height.

The present disclosure and certain features and advantages thereof will become more apparent from the following detailed description considered with reference to the accompanying drawings.

Drawings

These and other features and advantages of the present disclosure will become apparent from the following detailed description, the best mode, the claims, and the accompanying drawings, in which:

FIG. 1A is a schematic illustration of a vehicle including an engine assembly.

Fig. 1B is a perspective view illustrating a sliding camshaft cover having a position deviation actuator and a position detection sensor according to an exemplary embodiment.

FIG. 2A is a perspective view of the cam barrel of the first embodiment camshaft assembly in the first position.

FIG. 2B is a perspective view of the cam barrel of FIG. 2A of the first embodiment camshaft assembly in a second position.

FIG. 2C is a schematic illustration of a camshaft assembly of the engine assembly of FIGS. 2A-2B (the camshaft assembly rotating relative to an actuator pin), according to an exemplary non-limiting embodiment of the invention.

Fig. 2D is a schematic illustration of a cam barrel of a camshaft assembly according to yet another example of the present disclosure.

FIG. 3 is a schematic view of the example non-limiting camshaft assembly of FIGS. 2A-2C, with the camshaft assembly in a first position.

FIG. 4 is a schematic view of the example non-limiting camshaft assembly of FIGS. 2A-2C with the camshaft assembly in a second position.

Like reference numerals refer to like parts throughout the description of the several views of the drawings.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

Reference will now be made in detail to presently preferred compositions, embodiments and methods of the present invention, which constitute the best modes of practicing the invention presently known to the inventors. The drawings are not necessarily to scale. However, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure that may be embodied in various and alternative forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for any aspect of the disclosure and/or as a representative basis for teaching one skilled in the art to variously employ the present disclosure.

Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction and/or use are to be understood as modified by the word "about" in describing the broadest scope of the disclosure. Practice within the numerical ranges specified is generally preferred. Furthermore, unless expressly stated to the contrary: percent, "parts of," and ratio values are by weight; the description of a group or class of materials as suitable or preferred for a given purpose in connection with the present disclosure implies that mixtures of any two or more members of the group or class are equally suitable or preferred; the first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and compares favorably with conventional grammatical variations applied to the initially defined abbreviation; unless expressly stated to the contrary, measurement of an attribute is determined by the same techniques as previously or later referenced for the same attribute.

It is also to be understood that this disclosure is not limited to the particular embodiments and methods described below, as specific components and/or conditions may, of course, vary. Furthermore, the terminology used herein is for the purpose of describing particular embodiments of the disclosure only and is not intended to be limiting in any way.

It must also be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, reference to a component in the singular is intended to comprise a plurality of components.

The term "comprising" is synonymous with "including," having, "or" characterized by. These terms are inclusive and open-ended and do not exclude additional unrecited elements or method steps.

The phrase "consisting of does not include any elements, steps or ingredients not specified in the claims. The phrase "consisting essentially of" limits the scope of the claims to the specified materials or steps, as well as materials or steps that do not materially affect the basic and novel characteristics of the claimed subject matter.

The terms "comprising," "consisting of," and "consisting essentially of" may be used instead. Where one of these three terms is used, the presently disclosed and claimed subject matter can include the use of either of the other two terms.

Throughout this application, where publications are referenced, the disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this disclosure pertains.

The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses of the disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

Referring to the drawings, wherein like reference numbers correspond to like or similar components throughout the several figures, FIG. 1A schematically illustrates a vehicle 10, such as an automobile, truck, or motorcycle. The vehicle 10 includes an engine assembly 12. The engine assembly 12 includes an internal combustion engine 14 and a control module 16, such as an engine control module (ECU), in electronic communication with the internal combustion engine 14. The terms "control module," "control," "controller," "control unit," "processor," and similar terms mean any one or various combinations of one or more of the following: an Application Specific Integrated Circuit (ASIC), an electronic circuit, a central processing unit (preferably a microprocessor) and associated memory and storage (read only, programmable read only, random access, hard drive, etc.) that execute one or more software or firmware programs or routines, a combinational logic circuit, sequential logic circuit, input/output circuits and devices, appropriate signal conditioning and buffer circuits, and other components that provide the described functionality. "software," "firmware," "programs," "instructions," "routines," "code," "algorithms," and similar terms refer to any set of controller-executable instructions that include calibration and look-up tables. The control module 16 may have a set of control routines that are executed to provide the desired functionality. The routines are executed, such as by a central processing unit, and are operable to monitor inputs from sensing devices and other networked control modules, and execute control and diagnostic routines to control operation of actuators. The routine may be executed on an event basis or at fixed intervals.

The internal combustion engine 14 includes an engine block 18 that defines a plurality of

cylinders

20A, 20B, 20C, and 20D. In other words, the engine block 18 includes a first cylinder 20A, a second cylinder 20B, a third cylinder 20C, and a fourth cylinder 20D. Although FIG. 1A schematically illustrates four cylinders, internal combustion engine 14 may include more or fewer cylinders. The

cylinders

20A, 20B, 20C, and 20D are spaced apart from one another, but may be substantially aligned along the engine axis E. Each

cylinder

20A, 20B, 20C, and 20D is configured, shaped, and dimensioned to receive a piston (not shown). The pistons are configured to reciprocate within the

cylinders

20A, 20B, 20C, and 20D. Each

cylinder

20A, 20B, 20C, 20D defines a respective combustion chamber 22A, 22B, 22C, 22D. During operation of the internal combustion engine 14, an air/fuel mixture is combusted within the combustion chambers 22A, 22B, 22C and 22D to drive the pistons in a reciprocating manner. The reciprocating motion of the pistons drives a crankshaft (not shown) that is operably connected to wheels (not shown) of the vehicle 10. Rotation of the crankshaft causes the wheels to rotate, thereby propelling the vehicle 10.

To propel the vehicle 10, an air/fuel mixture should be introduced into the combustion chambers 22A, 22B, 22C, and 22D. To this end, internal combustion engine 14 includes a plurality of intake ports 24 fluidly coupled to an intake manifold (not shown). In the illustrated embodiment, the internal combustion engine 14 includes two intake ports 24 in fluid communication with each of the combustion chambers 22A, 22B, 22C, and 22D. However, the internal combustion engine 14 may include more or fewer intake ports 24 per combustion chamber 22A, 22B, 22C, and 22D. The internal combustion engine 14 includes at least one intake port 24 for each

cylinder

20A, 20B, 20C, 20D.

The internal combustion engine 14 also includes a plurality of intake valves 26 configured to control the flow of an intake charge through the intake ports 24. The number of intake valves 26 corresponds to the number of intake ports 24. Each intake valve 26 is at least partially disposed within a corresponding intake port 24. In particular, each intake valve 26 is configured to move between an open position and a closed position along the corresponding intake port 24. In the open position, the intake valve 26 allows an intake charge to enter the corresponding combustion chamber 22A, 22B, 22C, or 22D via the corresponding intake port 24. Conversely, in the closed position, intake valve 26 prevents intake charge from entering the corresponding combustion chamber 22A, 22B, 22C, or 22D via intake port 24.

As described above, internal combustion engine 14 may combust the air/fuel mixture once it enters combustion chamber 22A, 22B, 22C, or 22D. For example, the internal combustion engine 14 may combust an air/fuel mixture in the combustion chambers 22A, 22B, 22C, or 22D using an ignition system (not shown). This combustion produces exhaust gases. To exhaust these exhaust gases, the internal combustion engine 14 defines a plurality of exhaust ports 28. The exhaust port 28 is in fluid communication with the combustion chamber 22A, 22B, 22C or 22D. In the illustrated embodiment, two exhaust ports 28 are in fluid communication with each combustion chamber 22A, 22B, 22C, or 22D. However, more or fewer exhaust ports 28 may be fluidly coupled to each combustion chamber 22A, 22B, 22C, or 22D. The internal combustion engine 14 includes at least one exhaust port 28 for each

cylinder

20A, 20B, 20C, or 20D.

The internal combustion engine 14 also includes a plurality of exhaust valves 30 in fluid communication with the combustion chambers 22A, 22B, 22C, or 22D. Each exhaust valve 30 is at least partially disposed within a corresponding exhaust port 28. In particular, each intake valve 30 is configured to move between an open position and a closed position along the corresponding exhaust port 28. In the open position, the exhaust valve 30 allows exhaust gas to escape the corresponding combustion chamber 22A, 22B, 22C, or 22D via the corresponding exhaust port 28. The vehicle 10 may include an exhaust system (not shown) configured to receive and treat exhaust gas from the internal combustion engine 14. In the closed position, the exhaust valve 30 blocks exhaust gas from exiting the corresponding combustion chamber 22A, 22B, 22C, or 22D via the corresponding exhaust port 28.

As discussed in detail below, the intake and exhaust valves 26, 30 (fig. 1) are also commonly referred to as engine valves 66 (fig. 3-4) or simply valves. Each valve 66 (fig. 3-4) is operatively coupled or associated with a

cylinder

20A, 20B, 20C, or 20D. Thus, the valve 66 (fig. 3-4) is configured to control the flow of fluid (i.e., air/fuel mixture for the intake valve 26 and exhaust gas for the exhaust valve 30) to the

respective cylinder

20A, 20B, 20C, or 20D.

With further reference to FIG. 1A, the engine assembly 12 also includes a valvetrain system 32 configured to control operation of the intake and

exhaust valves

26, 30. Specifically, the valvetrain system 32 may move the intake and

exhaust valves

26, 30 between the open and closed positions based at least in part on an operating condition of the internal combustion engine 14 (e.g., engine speed). The valvetrain system 32 includes one or more camshaft assemblies 33 (see fig. 3-4) that are substantially parallel to the engine axis E. In the illustrated embodiment, the valvetrain system 32 includes two camshaft assemblies 33. One camshaft assembly 33 is configured to control operation of the intake valves 26 and the other camshaft assembly 33 may control operation of the exhaust valves 30.

Referring now to FIG. 1B, an illustration of a sliding camshaft cover 40 having position offset actuators (34A-34D) and a position detection sensor 52 according to an exemplary embodiment is provided. The sliding camshaft cover 40 shields the intake camshaft 82 and the exhaust camshaft 84 as protection against the external environment and keeps oil splash generated by the engine operation. The position detection sensor 52 is disposed in the sliding camshaft cover 40 adjacent to the at least one position displacement slot such that the position of the at least one cam barrel 56 (e.g., the camshaft barrel (56)) may be detected by the position detection sensor(s) 52 described herein. The position detection sensor 52 may be of the type used for position detection suitable for the engine environment, including but not limited to a Hall effect sensor.

Referring back to FIG. 1A, in addition to the camshaft assembly 33, the valvetrain assembly 32 includes a plurality of

actuators

34A, 34B, such as solenoids, in communication with the control module 16. The

actuators

34A, 34B may be electrically connected to the control module 16, and thus may be in electronic communication with the control module 16. The control module 16 may be part of a valvetrain system 32. In the illustrated embodiment, the valvetrain system 32 includes a first actuator 34A, a second actuator 34B.

Actuators

34A and 34B are operatively associated with the first cylinder 20A and the second cylinder 20B, wherein the actuator 34A displaces the lobe in a forward direction and the actuator 34B displaces the lobe back in a rearward direction. Similarly,

actuators

34C and 34D are operatively associated with the third cylinder 20C and the fourth cylinder 20D, wherein the actuator 34C displaces the lobes in the forward direction in two steps, while the actuator 34D displaces the lobes back in the rearward direction.

Referring now to fig. 3-4, the camshaft assembly 33 includes

actuators

34A, 34B (fig. 3-4) and an axially movable structure 44 mounted on the base shaft 35, wherein the axially movable structure 44 includes a plurality of lobe sets 46 and a cam barrel 56. The axially movable structure 44 moves along the base shaft 35 in an axial direction along the longitudinal axis X, 37 of the base shaft 35, but is rotationally fixed to the base shaft 35. The cam barrel 56 includes an inner wall 94 and an outer wall 90 defining the control groove 60 therebetween. The control groove 60 further includes a first region and a second region, wherein the second region 69 defines a fixed narrow control groove width 72 and the first region 67 defines a gradually changing control groove width 70. The

actuators

34A, 34B (fig. 3-4) displace the axially movable structure 44 relative to the base shaft 35 between a first position 75 and a second position 77. A recess 92 is defined in the outer wall 90 of the cam barrel 56 such that the recess 92 is disposed adjacent the second region 69 of the control groove 60 (fig. 2A-2C).

The camshaft assembly 33 may also include a sensor 52 configured to align with the axially moveable structure 44 along a first sensor path 88 (fig. 2A) when the axially moveable structure 44 is moved to the first position 75 (fig. 3). The aforementioned sensor 52 may also be configured to align with the axially moveable structure 44 along a second sensor path 86 (fig. 2B) when the axially moveable structure 44 is moved to the second position 77 (fig. 4). As shown in fig. 2A, the first sensor path 88 covers an outer wall 90 and a recess 92 defined in the outer wall 90. As shown in fig. 2B, the second sensor path 86 covers the control recess 60 and the outer wall 90. However, it is understood that the recess 92 is disposed outside of the second sensor path.

The engine control module 16 of fig. 1A communicates with the

actuators

34A, 34B (fig. 3-4) and the sensors 52. However, the engine control module 16 also communicates with the recess 92 and the outer wall 90 via the sensor 52 to detect/confirm the first position 75 of the axially movable structure when the axially movable structure is in the first position 75 (fig. 3). In the arrangement shown in fig. 3, the recess 92 and the outer wall 90 are aligned with the sensor 52 in the first sensor path 88 (see fig. 2A). The sensor 52 is configured to send a feedback signal 79 (in the form of a first data set 81) to the engine control module 16 depending on the configuration of the cam barrel 56 along a first sensor path 88. More specifically, the recess 92 and the outer wall 90 are configured to communicate with the engine control module 16 via the sensor 52 to detect/confirm the first position 75 of the axially movable structure 44 when the recess 92 and the outer wall 90 are aligned with the sensor 52 in the first sensor path 88.

Similarly, the control recess 60 and the outer wall 90 may also be configured to communicate with the engine control module 16 via the sensor 52 to detect/confirm the second position 77 of the axially moveable structure 44 when the control recess 60 and the outer wall 90 are aligned with the sensor 52 in the second sensor path 86. (see fig. 2B, fig. 4). The sensor 52 is configured to send a feedback signal 79 (in the form of a second data set 83) to the engine control module 16 depending on the configuration of the cam barrel 56 along a second sensor path 86.

As shown in fig. 3-4, each of the plurality of lobe sets 46 includes a first cam lobe 54B adjacent a second cam lobe 54A in the axial directions X, 37. The first cam lobe 54B is configured such that when the axially moveable structure 44 is in the first position 75, the first cam lobe 54B is engaged with the engine valve 66. Similarly, the second cam lobe 54A is configured such that when the axially movable structure 44 is in the second position 77, the second cam lobe 54A is engaged with the engine valve 66. The first cam lobe 54B has a first maximum lobe height 78 (see fig. 4) and the second cam lobe 54A has a second maximum lobe height 76 (see fig. 4), wherein the first maximum lobe height 78 is different than the second maximum lobe height 76.

In yet another embodiment of the present disclosure shown in FIG. 1A, engine assembly 12 includes engine control module 16, internal combustion engine 14, camshaft assembly 33,

actuators

34A, 34B, and sensor 52. The internal combustion engine 14 includes a first cylinder 20A, a second cylinder 20B, a first valve 66 operatively coupled to the first cylinder 20A, and a second valve 66 operatively coupled to the second cylinder 20B. The camshaft assembly 33 may be coupled to first and second valves 66 of the internal combustion engine 14. The camshaft assembly 33 further includes a base shaft 35 and an axially movable structure 44 mounted on the base shaft 35. The base shaft 35 may extend along the longitudinal axis x, 37 and be configured to rotate about the longitudinal axis x, 37. The axially moveable structure 44 is configured to move between a first position 75 and a second position 77 on the base shaft 35, while the axially moveable structure 44 is rotationally fixed to the base shaft 35. The aforementioned axially movable structure 44 includes the cam barrel 56 having the control groove 60 defined between the inner wall 94 and the outer wall 90 of the cam barrel 56. The control groove 60 may define a fixed narrow groove width 72 throughout the second region 69 and a gradually changing enlarged groove width 70 in at least a portion of the first region 67 of the cam barrel 56.

Referring to fig. 3-4, the

actuators

34A, 34B are configured to move the axially movable structure 44 between a first position 75 and a second position 77 via the actuator pins 64A, 64B engaging the control groove 60 in the cam barrel 56 in accordance with an output signal 74 received from the engine control module 16. The sensor 56 is configured to send a first data set 81 (feedback signal(s) 79) to the engine control module 16 (see fig. 3) when the axially moveable structure is in the first position 75. The sensor 52 is further configured to send a second data set 83 ((plurality of feedback signals 79) to the engine control module 16 when the axially moveable structure 44 is in the second position 77. (see FIG. 4). It will be appreciated that the recess 92 is defined in the outer wall 90 of the cam barrel 56 and is aligned with the sensor 52 when the axially moveable structure 44 is in the first position 75, regardless of the stack-up tolerance 42.

With respect to the example cam barrel 56 shown in fig. 2A-2C and 3-4, the enlarged groove width 70 of the first region 67 may be greater than the fixed narrow groove width 72 of the second region 69. Regardless of the configuration of the control recesses, the plurality of lobe sets 46 are configured to rotate synchronously with the cam barrel 56 as the axially moveable structure 44 rotates with the base shaft 35. As shown in FIG. 2D, another example control groove 60 is shown having an outer wall 90 and a recess 92.

With particular reference to the example shown in fig. 3-4, the camshaft assembly 33 includes one or more (two in fig. 3-4) axially movable structures 44 mounted on the base shaft 35. The base shaft 35 extends along longitudinal axes X, 37. The base shaft 35 may include a first shaft end 36 and a second shaft end 38 opposite the first shaft end 36. In the non-limiting example of fig. 3-4, each axially movable structure 44 includes a lobe set 46A-46D and a cam barrel 56, the cam barrel 56 being integral with the lobe set 46A-46D or secured to the lobe set 46A-46D. The axially movable structure 44 is configured to move axially along the longitudinal axes X, 37 relative to the base shaft 35. However, the axially movable structure 44 is rotationally fixed to the base shaft 35. Thus, the axially movable structure 44 rotates synchronously with the base shaft 35. The base shaft 35 may include spline features 48, the spline features 48 for maintaining the angular alignment of the axially movable structure 44 with the base shaft 35, and also for transmitting drive torque between the base shaft 35 and the axially movable structure 44.

In the example shown in fig. 3-4, the axially movable structures 44 are axially spaced from each other along the longitudinal axes X, 37. However, as described herein, when the axially movable structure 44 and optional journal are axially mounted on the base shaft 35, tolerance stacks 41, 42 (see fig. 2A-2B) may occur in the camshaft assembly. Regardless of the tolerance stack-up (or configuration variations) that may occur, the sensor 52 of the camshaft assembly of the present disclosure will be able to accurately detect the axial position of the axially movable structure 44 on the camshaft assembly, as well as the rotational position of the axially movable structure on the camshaft assembly.

As shown in fig. 3, the axially moveable structure 44 is shown in a first position 75. In the first position 75, the sensor 52 may be in communication with the cam barrel 56 of the present disclosure, wherein when the axially moveable structure has been moved to the first position 75 as shown in fig. 3, the sensor 52 may be substantially aligned with the cam barrel 56 along a first sensor path 88 (as shown in fig. 2A), wherein the first sensor path 88 covers an outer wall 90 of the cam barrel 56 and a recess in the outer wall 90. In this position, the sensor 52 is configured to provide a feedback signal 79 (see fig. 1, 3) to the control module 16 to identify the axial and rotational position of the camshaft assembly. Specifically, the algorithm in the control module 16 may require data (via the feedback signal 79 from the sensor 52) that identifies whether the axially moveable structure 44 is in the first position 75 (shown in fig. 3). To do so, the feedback signal 79 is compared to a model in the control module to determine whether the recess 92 and outer wall 90 are aligned with the sensor 52. When the axially moveable structure 44 is in the first position 75 (as shown in fig. 3), the cam barrel 56 should be substantially aligned with the sensor 52 along the first sensor path 88 such that the recess 92 and the outer wall 90 are aligned with the sensor 52 (and the feedback signal 79 reflects that the recess 92 and the outer wall 90 are in communication with and aligned with the sensor 52). When the feedback signal 79 matches the desired pattern of first positions, the control module can accurately confirm or determine that the axially movable structure 44 is in the first position 75 (fig. 3), because (as shown in fig. 2A) the sensor 52 will be able to obtain consistent and reliable readings, given that the structure of the cam barrel 56 (the outer wall 90 and the recess 92) is consistent (invariant) at the first sensor path 88 in the area around the first sensor path 88, regardless of whether the first sensor path 88 varies in the positive or negative direction with the first stack tolerance 42 along the longitudinal axis X, 37.

In addition to determining or confirming axial movement of the axially moveable structure 44 when the structure 44 is in the first position 75, the algorithm 25 in the control module 16 also requires data (via a feedback signal 79 from the sensor) to determine/confirm the rotational position of the axially moveable structure 44 and its corresponding set of lobes (the rotational position of the lobes engaged with the valve). Assuming that the recess 92 and the outer wall 90 are in a fixed angular position relative to the cam lobe, the control module 16 (and its associated algorithm) is also able to determine or confirm the exact rotational position of the lobe 54B engaged with the valve 66 when the axially moveable structure 44 is in the first position.

Each axially movable structure 44 may be a unitary structure. Thus, the lobe sets 46A, 46B, 46C, 46D and the cam barrel 56 of the same axially movable structure 44 may be simultaneously moved/rotated relative to the base shaft 35. Although the figures illustrate each axially moveable structure 44 as including four lobe sets 46A, 46B, 46C, 46D, it should be understood that each axially moveable structure 44 may include more or fewer lobe sets.

With particular reference to fig. 4, the axially moveable structure is shown in a second position 77. When the structure 44 is in the second position 77, the control recess 60 and the outer wall 90 are configured to communicate with the sensor 52 at the second sensor path 86 (fig. 2B). The example control groove 60 of fig. 3-4 may optionally include a central peninsula (shown in phantom as element 47) in the first region 67 that creates two paths 61 in the control groove 60 in the cam barrel 56. Accordingly, when the axially moveable structure 44 is in the second position 77 as shown in fig. 4, the sensor 52 may be in communication with the cam barrel 56 of the present disclosure, wherein the sensor 52 may be substantially aligned with the cam barrel 56 along the cam barrel 56 (as shown in fig. 2B), wherein the second sensor path 86 covers the control groove 60 and the outer wall 90 of the cam barrel 56. In this position, the sensor 52 is configured to also provide a feedback signal 79 or a second data set (see fig. 1A, 4) to the control module 16 to identify the axial and rotational position of the camshaft assembly. Specifically, the algorithm 25 in the control module 16 may require data (via the feedback signal 79 from the sensor 52) that identifies whether the axially moveable structure 44 is in the second position 77 (shown in fig. 4). To do so, the feedback signal 79 (second data set 83) is compared to the model 27 in the control module 16 to detect/confirm whether the control groove 60 and the outer wall 90 are aligned with the sensor 52 (at the second sensor path 86 in fig. 2B).

When the feedback signal 79 (second data set 83) matches the desired pattern of the second position 77, the control module 16 can accurately confirm or determine that the axially moveable structure 44 is actually in the second position 77 (fig. 4). It should be appreciated that the second data set 83 is distinct from the first data set 81 obtained along the first sensor path 88. Because of this significant difference between the data readings at the first sensor path 88 and the second sensor path 86, ambiguity regarding the position of the axially moveable structure in the camshaft assembly is eliminated and a more accurate system is provided regardless of stack-up tolerances 41, 42 or manufacturing variations 41, 42.

The algorithm in the control module 16 may also require data (via a feedback signal 79 from the sensor) to determine/confirm the rotational position of the axially moveable structure and its corresponding lobe set (the rotational position of the lobes engaged with the valve) when the axially moveable structure is in the second position 77. The control module 16 (and its associated algorithm) can also determine or confirm the exact rotational position of the lobe 54B engaged with the valve 66 when the axially movable structure 44 is in the second position, given the control module's knowledge: (1) in the second position, a fixed angular position of control groove 60 and outer wall 90 relative to cam lobe 54A (which engages valve 66); and (2) control the exact rotational position of the groove 60 and the outer wall 90 (via the feedback signal 79 from the sensor 52).

Accordingly, in all embodiments of the present disclosure, the cam barrel 56 includes an outer wall 90, wherein the outer wall 90 includes a groove wall surface 98 (forming a portion of the control groove 60), an upper surface 100, and a side surface 102 (see fig. 2A-2C). As shown in fig. 2A-2C, an outer wall 90 is defined on the cam barrel 56 and defines one-half of the control groove 60. As shown, the outer wall 90 further defines a recess 92, wherein the recess 92 may optionally be disposed adjacent or proximate to the second region 69 of the control groove 60, the second region 69 defining a fixed, narrower groove width 72 (see fig. 2A-2C). It should be appreciated that the model 27 and algorithm 25 in the control module 16 are calibrated according to the uniquely selected configuration of the outer wall 90 and the recess 92 relative to the first region 69 of the control groove 60.

It will be appreciated that the second sensor path 86 may vary along the axes X, 37 by tolerance stack-up (element 42) as shown in fig. 2B, and the first sensor path 88 may vary along the axes X, 37 by tolerance stack-up (element 41) as shown in fig. 2A. Furthermore, sensor 52 will detect the absence of material (recess 92 in fig. 2A) in second region 69 only when sensor 52 is aligned in first sensor path 88 (in first position 75). Conversely, sensor 52 will detect material (outer wall 90) in second region 69 only when sensor 52 is aligned in second sensor path 86 (at second location 77). Again, due to the significant difference between the feedback signals 79 of the first and

second sensor paths

86, 88 in the example second region, the camshaft assembly 33 of the present disclosure is significantly disambiguated in determining the axial position of the structure 44 relative to the base shaft 35, regardless of the stack-up tolerances 41, 42.

The control module 16 and/or the sensor are configured to detect the absence of material (in the form of an enlarged control groove width 70) along a second sensor path 86 (see fig. 2B) as the sensor 52 passes over the second region 69. The signal 79 (see FIG. 1A) from the sensor 52 is continuously sent from the sensor 52 to the control module 16 (see FIG. 1A) so that the algorithm 25 in the control module 16 can accurately determine the axial and/or rotational position of the camshaft assembly regardless of the tolerance stack-ups 41, 42.

With respect to the example actuator of fig. 3-4, the

actuators

34A, 34B are configured to move an axially movable structure between a first position (shown in fig. 2A and 3) and a second position (shown in fig. 2B and 4). Each

actuator

34A, 34B includes an actuator body 62A, 62B, with a first pin 64A and a second pin 64B movably coupled to each actuator body 62A, 62B. The first and

second pins

64A, 64B of each

actuator

34A, 34B are axially spaced from one another and are movable independently of one another. Specifically, each of the first and

second pins

64A, 64B may be movable between a retracted position 71 and an extended position 73 relative to the corresponding actuator body 62A, 62B in response to an input or command from the control module 16 (fig. 1). In the retracted position 71, the first pin 64A or the second pin 64B is not disposed in the control recess 60. Conversely, in the extended position 73, the first pin 64A or the second pin 64B may be at least partially disposed in the control recess 60. Thus, the first and

second pins

64A, 64B may move toward and away from the control groove 60 of the cam barrel 56 in response to an input or command from the control module 16 (fig. 1). Thus, the first and

second pins

64A, 64B of each

actuator

34A, 34B may move relative to the corresponding cam barrel 56 in a direction substantially perpendicular to the longitudinal axes X, 37. Thus, as shown in fig. 4, when the axially moveable structure 44 is in the second position 77, the sensor 52 is aligned with the second sensor path 86 shown in fig. 2B. Similarly, as shown in FIG. 3, when the axially moveable structure is in the first position 75, the sensor 52 is aligned with the first sensor path 88 shown in FIG. 2A.

It will be appreciated that when the second pin 64B is in the extended position 73, the axially moveable structure 44 may be axially moved relative to the base shaft 35 from a first position 75 (fig. 3) to a second position 77 (fig. 4) as the base shaft 35 is rotated about the longitudinal axis 37. The second pin 64B is at least partially disposed in the control recess 60, and the second pin 64B is configured to travel along at least a portion 85 of the second side 80B of the first region 67 in the control recess 60 and then into the second region 69 of the control recess 60. Further, it can also be appreciated that the axially movable structure 44 can be axially moved from the second position 77 (FIG. 4) to the first position 75 (FIG. 3) when the base shaft 35 is rotated about the longitudinal axis 37, the first pin 64A is in the extended position 73, and when the first pin 64A is at least partially disposed in the control recess 60, the first pin 64A travels along at least a portion 85 of the first side 80A of the first region 67 in the control recess 60 and then into the second region 69 of the control recess 60. The enlarged width 70 (gradual width 70) gradually changes within the first region 67. Regardless of the varying expanded width 70 (gradual width 70) of the control groove 60 in the first region 67, any expanded width 70 or gradual width 70 defined in the first region 67 is greater than the narrow fixed width 72 that remains constant in the second region 69. .

As described above, each of the plurality of lobe sets 46A, 46B, 46C, 46D in the axially movable structure 44 includes a plurality of

cam lobes

54A, 54B. The cam barrel 56 in the axially movable structure 44 defines a control groove 60, the control groove 60 being defined by at least one path 61 around a circumference 63 of the cam barrel 56 such that the at least one path 61 is defined by a first region 67 and a second region 69. The

actuators

34A, 34B include actuator bodies 62A, 62B and first and

second pins

64A, 64B that are each movably coupled to the actuator bodies 62A, 62B such that each of the first and

second pins

64A, 64B is movable relative to the actuator bodies 62A, 62B between a retracted position 71 and an extended position 73. The first pin 64A and the second pin 64B are configured to travel along at least one path 61 defined by the control groove 60. However, when the base shaft 35 is rotated about the longitudinal axis 37 and the second pin 64B is in the extended position 73 (with the second pin 64B at least partially disposed in the control recess 60), the axially moveable structure 44 may be axially moveable relative to the base shaft 35 from a first position (fig. 3)75 to a second position 77 (fig. 4). In this configuration, the second pin 64B is configured to travel along at least a portion 85 of the second side 80B of the first region 67 in the control recess 60 and then into the second region 69 of the control recess 60. Similarly, the axially moveable structure 44 may be axially moveable relative to the base shaft 35 from a second position (fig. 4)77 to a first position 75 (fig. 3) when the base shaft 35 is rotated about the longitudinal axis 37 and the first pin 64A is in the extended position 73 (such that the first pin 64A is at least partially disposed in the control recess 60). In this configuration, the first pin 64B is configured to travel along at least a portion 85 of the first side 80A of the first region 67 in the control recess 60 and then into the second region 69 of the control recess 60. As shown in fig. 2A, it will be appreciated that the first region 67 of the control groove 60 defines an enlarged width 70 in the control groove 60, and the second region 69 of the control groove 60 defines a narrow width 72 in the control groove 60, wherein the narrow width 72 is less than the enlarged width 70. The enlarged width 70 gradually changes within the first region 67.

While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and the legal equivalents thereof.

Claims

1. A camshaft assembly, comprising:

a base shaft extending along a longitudinal axis;

an axially movable structure mounted on the base shaft and axially movable via an actuator relative to the base shaft between a first position and a second position while also rotationally fixed to the base shaft, the axially movable structure comprising:

a plurality of lobe sets, each of the lobe sets including a plurality of cam lobes; and

a cam barrel having a control groove defined between an inner wall and an outer wall of the cam barrel, the control groove including a first region having a fixed narrow groove width between the inner wall and the outer wall and a second region having an enlarged groove width between the inner wall and the outer wall; and

a recess defined in an outer wall of the cam barrel such that the recess is disposed adjacent to the first region;

wherein the recess is defined in a first region of the cam barrel.

2. The camshaft assembly of claim 1, further comprising a sensor configured to align with the axially moveable structure along a first sensor path when the axially moveable structure is moved to the first position, and the sensor configured to align with the axially moveable structure along a second sensor path when the axially moveable structure is moved to the second position.

3. The camshaft assembly of claim 2, wherein the first sensor path covers the outer wall and a recess defined in the outer wall.

4. A camshaft assembly as claimed in claim 3, wherein the second sensor path covers the control recess and the outer wall.

5. The camshaft assembly of claim 4, further comprising a control module in communication with the actuator and the sensor.

6. The camshaft assembly of claim 5, wherein each of the plurality of lobe sets includes a first cam lobe adjacent a second cam lobe.

7. The camshaft assembly of claim 6, wherein the first cam lobe is configured to engage an engine valve when the axially movable structure is in the first position.

8. The camshaft assembly of claim 7, wherein the recess and the outer wall are configured to communicate with an engine control module via a sensor to detect a first position of the axially moveable structure when the recess and the outer wall are aligned with the sensor in a first sensor path.

9. The camshaft assembly of claim 8, wherein the control recess and the outer wall are configured to communicate with an engine control module via the sensor to detect a second position of the axially moveable structure when the control recess and the outer wall are aligned with the sensor in a second sensor path.

10. An engine assembly, comprising:

an internal combustion engine including a first cylinder, a second cylinder, a first valve operably coupled to the first cylinder, and a second valve operably coupled to the second cylinder;

an engine control module;

a camshaft assembly operably coupled to the first valve and the second valve, wherein the camshaft assembly comprises:

a base shaft extending along a longitudinal axis, the base shaft configured to rotate about the longitudinal axis;

an axially movable structure axially movable between a first position and a second position on the base shaft and rotationally fixed to the base shaft,

wherein the axially movable structure further comprises;

a cam barrel having a control groove defined between an inner wall and an outer wall of the cam barrel, the control groove defining a fixed narrow groove width throughout a first region and a gradually changing enlarged groove width in at least a portion of a second region of the cam barrel; and

an actuator configured to move the axially movable structure between the first position and the second position via a control groove in the cam barrel in accordance with an output signal from the engine control module; and

a sensor configured to send a first data set to the engine control module when the axially moveable structure is in a first position and configured to send a second data set to the engine control module when the axially moveable structure is in the second position;

wherein a recess is defined in an outer wall of the cam barrel and the recess is aligned with the sensor when the axially moveable structure is in the first position.