阅读说明：本技术 滑动凸轮轴组件 (Sliding camshaft assembly ) 是由 B·R·卡恩 H·W·阮 D·切托尔 于 2019-05-29 设计创作，主要内容包括：本公开涉及一种凸轮轴组件,该凸轮轴组件包括基轴、具有圆柱凸轮和多个凸角组的可轴向移动结构以及致动器。圆柱凸轮限定具有扩大区和收敛区的单个控制槽。致动器包括具有第一和第二销的致动器本体。第一和第二销中的每个销均可相对于致动器本体在内缩位置与外伸位置之间移动。当第二销沿扩大区的第二侧的至少一部分行进然后进入收敛区时,可轴向移动结构可从第一位置移动到第二位置。当第一销沿扩大区的第一侧的至少一部分行进时,在进入收敛区之前,可轴向移动结构也可从第二位置移动到第一位置。(The present disclosure relates to a camshaft assembly including a base shaft, an axially moveable structure having a cylindrical cam and a plurality of lobe sets, and an actuator. The cylindrical cam defines a single control slot having an enlarged region and a converging region. The actuator includes an actuator body having first and second pins. Each of the first and second pins is movable relative to the actuator body between a retracted position and an extended position. The axially moveable structure may be moveable from the first position to the second position as the second pin travels along at least a portion of the second side of the enlarged region and then enters the converging region. The axially moveable structure may also be moveable from the second position to the first position prior to entering the converging region as the first pin travels along at least a portion of the first side of the enlarged region.)

1. A camshaft assembly, comprising:

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

an axially moveable structure mounted on the base shaft, the axially moveable structure being axially moveable relative to the base shaft, the axially moveable structure being rotationally fixed with the base shaft, wherein the axially moveable structure comprises:

a plurality of lobe sets, each of the lobe sets comprising a plurality of cam lobes, wherein the axially moveable structure comprises a cylindrical cam defining a control slot and the control slot defines a single path around a circumference of the cylindrical cam, wherein the single path is defined by an expansion region and a convergence region;

an actuator comprising an actuator body and first and second pins, each pin movably coupled with the actuator body such that each of the first and second pins is movable relative to the actuator body between a retracted position and an extended position, wherein the first and second pins are configured to travel along a single path defined by the control slot;

wherein the axially moveable structure is axially moveable relative to the base shaft from a first position to a second position when the base shaft is rotated about the longitudinal axis, the second pin is in an extended position, the second pin is at least partially located in a control slot, and the second pin is configured to travel along at least a portion of a second side of an enlarged region in the control slot before entering a converging region of the control slot; and is

Wherein the axially moveable structure is axially moveable relative to the base shaft from a second position to a first position when the base shaft is rotated about the longitudinal axis, the first pin is in an extended position, the first pin is at least partially disposed in a control slot, and the first pin is configured to travel along at least a portion of a first side of an enlarged region in the control slot before entering a converging region of the control slot.

2. The camshaft assembly of claim 1, wherein the enlarged region of the control slot defines an enlarged width and the converging region of the control slot defines a narrow width that is less than the enlarged width.

3. The camshaft assembly of claim 2, further comprising a control module in communication with the actuator, wherein at least one of the first and second pins is configured to move between a retracted position and an extended position in response to an input from the control module.

4. The camshaft assembly of claim 2, wherein the plurality of cam lobes includes first and second cam lobes axially spaced relative to each other.

5. The camshaft assembly of claim 4, wherein the plurality of cam lobes are defined on an axially moveable structure.

6. The camshaft assembly of claim 5, wherein 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.

7. An engine assembly, comprising:

an internal combustion engine comprising a first cylinder, a second cylinder, a first valve operably coupled with the first cylinder, and a second valve operably coupled with the second cylinder, wherein the first valve is configured to control fluid flow in the first cylinder and the second valve is configured to control fluid flow in the second cylinder; and

a camshaft assembly operably coupled to the first and second valves, 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 moveable structure mounted on the base shaft, the axially moveable structure being axially moveable relative to the base shaft, the axially moveable structure being rotationally fixed with the base shaft, wherein the axially moveable structure comprises:

a plurality of lobe sets, each of the lobe sets comprising a plurality of cam lobes, wherein the axially moveable structure comprises a cylindrical cam and the cylindrical cam defines a control slot, wherein the control slot defines a single path around a circumference of the cylindrical cam and the single path is defined by an expansion region and a convergence region;

an actuator comprising an actuator body and first and second pins, each pin movably coupled with the actuator body such that each of the first and second pins is movable relative to the actuator body between a retracted position and an extended position, wherein the first and second pins are configured to travel along a single path defined by the control slot;

wherein the axially moveable structure is axially moveable relative to the base shaft from a first position to a second position when the base shaft is rotated about the longitudinal axis, the second pin is in an extended position, the second pin is at least partially located in a control slot, and the second pin is configured to travel along at least a portion of a second side of an enlarged region in the control slot before entering a converging region of the control slot; and is

Wherein, when the base shaft is rotated about the longitudinal axis, an axially moveable structure is axially moveable relative to the base shaft from a second position to a first position, the first pin is in an extended position, the first pin is at least partially located in a control slot, and the first pin is configured to travel along at least a portion of a first side of an enlarged region in the control slot before entering a converging region of the control slot.

8. The engine assembly of claim 7, wherein the enlarged region of the control slot defines an enlarged width and the converging region of the control slot defines a narrow width that is less than the enlarged width.

9. The engine assembly of claim 8, wherein the lobe set is configured to rotate synchronously as the axially moveable structure rotates with the base shaft.

10. The engine assembly of claim 8, further comprising a control module in communication with the actuator, wherein at least one of the first and second pins is configured to move between a retracted position and an extended position in response to an input from the control module.

Technical Field

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

Background

Motor vehicles currently in production, such as modern automobiles, are initially equipped with a power system (powertrain) that functions to propel the vehicle and power the onboard vehicle electronics. The powertrain system comprises a driveline (drivetrain), but is often misclassified as a driveline, which is typically comprised of a prime mover (e.g., an engine) that delivers driving power through a multi-speed transmission to the final driveline of the vehicle (e.g., rear differential, axles, and wheels). Past automobiles were typically powered by reciprocating piston Internal Combustion Engines (ICEs) because of their ready availability, relatively low cost, light weight, and overall efficiency. Such engines include, as some examples, two-stroke and four-stroke compression ignition diesel engines, four-stroke spark ignition gasoline engines, six-stroke engine configurations, and rotary cylinder engines. Hybrid vehicles, on the other hand, employ an alternative power source (e.g., a motor-generator) to propel the vehicle, thereby minimizing reliance on engine power and improving overall fuel economy.

A typical overhead valve internal combustion engine includes an engine block with cylinder bores each having a piston reciprocally movable therein. Coupled to the upper surface of the engine block is a cylinder head that, in conjunction with the piston and cylinder bore, forms a variable volume combustion chamber. These reciprocating pistons serve to convert pressure generated by igniting a fuel and air mixture in the combustion chamber into rotational force to drive the crankshaft. The cylinder head defines intake ports through which air provided by an intake manifold is selectively introduced into each combustion chamber. Also defined in the cylinder head are exhaust ports through which exhaust gases and byproducts of combustion are selectively exhausted from the combustion chamber to an exhaust manifold. The exhaust manifold collects exhaust gases and mixes them accordingly for recirculation into the intake manifold, delivery to a turbine-driven turbocharger, or exhaust from the ICE via the exhaust system.

The cylinder head (or heads if the engine has multiple banks of cylinders) may house the valvetrain of the ICE: intake valves, exhaust valves, rocker arms, pushrods, and (in some cases) camshafts. The valvetrain is part of the power train subsystem responsible for controlling the amount of fuel-laden air and exhaust gases entering and exiting the engine combustion chambers at any given point in time. Engine torque and power output are varied by adjusting valve lift and timing, either directly or indirectly, using cam lobes on a rotating camshaft, which is accomplished by actuating intake and exhaust valves. Different engine speeds typically require different valve timing and lift to achieve optimal performance. In general, low engine speeds require the valve to be opened a relatively small amount over a short period of time, while high engine speeds require the valve to be opened a relatively large amount over a longer period of time for optimum performance. By adding the ability to select between different cam profiles to drive the valve differently at different speeds and loads, the engine is able to better optimize performance over a greater range of engine operating conditions.

Disclosure of Invention

The present disclosure provides a sliding camshaft assembly that includes a base shaft, an axially moveable structure having a cylindrical cam and a plurality of lobe sets, and an actuator. The cylindrical cam defines a single control slot having an enlarged region and a converging region. The actuator includes an actuator body having first and second pins. The first and second pins each move relative to the actuator body between a retracted position and an extended position. The axially moveable structure may be moveable from the first position to the second position as the second pin travels along at least a portion of the second side of the enlarged region and then enters the converging region. The axially moveable structure may also be moveable from the second position to the first position as the first pin travels along at least a portion of the first side of the enlarged region prior to entering the converging region.

Accordingly, in one embodiment, an exemplary sliding camshaft assembly according to the present disclosure includes: a base shaft, an axially moveable structure having a cylindrical cam and a plurality of lobe sets, and an actuator. The base shaft extends along a longitudinal axis, and the base shaft may be configured to rotate about the longitudinal axis. The axially movable structure is configured to move along the longitudinal axis relative to the base shaft. However, the axially movable structure is rotationally fixed to the base shaft. Each of the plurality of lobe sets in the axially moveable structure includes a plurality of cam lobes. The cylindrical cam in the axially moveable structure defines a control slot that is defined by a single path around a circumference of the cylindrical cam such that the single path is defined by an enlarged region and a converging region. The actuator includes an actuator body and first and second pins each movably coupled to the actuator body such that the first and second pins are each movable relative to the actuator body between a retracted position and an extended position. The first and second pins are configured to travel along a single path defined by the control slot. However, when the base shaft is rotated about the longitudinal axis, the axially moveable structure may be axially moved relative to the base shaft from a first position to a second position, and the second pin is in the extended position, wherein the second pin is at least partially located in the control slot. In this arrangement, the second pin is configured to travel along at least a portion of the second side of the enlarged region in the check slot before entering the converging region of the check slot. Similarly, the axially moveable structure may be axially moveable relative to the base shaft from the second position to the first position when the base shaft is rotated about the longitudinal axis, and the first pin is in the extended position, thereby disposing the first pin at least partially within the control slot. In this arrangement, the first pin is configured to travel along at least a portion of the first side of the enlarged region in the check slot before entering the converging region of the check slot. It should be understood that the enlarged region of the control slot defines an enlarged width in the control slot and the converging region of the control slot defines a narrow width in the control slot, wherein the narrow width is less than the enlarged width.

The control module may be in communication with the actuator to actuate the first and/or second pins in response to an input from the control module such that the first and/or second pins are movable between the retracted and extended positions. Further, with respect to the plurality of cam lobes defined on the axially moveable structure (within each lobe set), such cam lobes may include at least a first cam lobe and a second cam lobe axially spaced relative to one another. The first cam lobe has a first maximum lobe height and the second cam lobe has a second maximum lobe height. The first maximum lobe height may be different than the second maximum lobe height in order to vary the displacement of the valve.

In yet another embodiment of the present disclosure, an engine assembly is provided that includes an internal combustion engine, a camshaft assembly, and an actuator. The internal combustion engine may include: the system 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 first valve may be configured to control fluid flow in the first cylinder, while the second valve is configured to control fluid flow in the second cylinder. The camshaft assembly includes a base shaft and an axially movable structure. The base shaft rotates about (and extends along) a longitudinal axis. The axially moveable structure may be mounted on the base shaft such that the axially moveable structure is axially moveable relative to the base shaft along the longitudinal axis. However, the axially movable structure is rotationally fixed to the base shaft. The axially movable structure includes a plurality of lobe sets and a cylindrical cam. Each lobe set includes a plurality of cam lobes. Each lobe set (plurality of cam lobes) includes first and second cam lobes axially spaced relative to each other. Each of the first cam lobes has a first maximum lobe height and each of the second cam lobes has a second maximum lobe height. The first maximum lobe height may be different than the second maximum lobe height.

The cylindrical cam of the axially movable structure defines a control slot that is a single path around a circumference of the cylindrical cam. The aforementioned single path is defined by an expansion region and a convergence region. In the case of an actuator, the actuator includes an actuator body and first and second pins, each movably coupled to the actuator body. The first and second pins are each movable relative to the actuator body between a retracted position and an extended position, and thus the first and second pins are each configured to travel along a single path defined by the control slot.

However, when the second pin is in the extended position such that the second pin is at least partially disposed in the control slot, the axially moveable structure may be axially moveable relative to the base shaft from the first position to the second position as the base shaft is rotated about the longitudinal axis. In this arrangement, the second pin is configured to travel along at least a portion of the second side of the enlarged region in the check slot before entering the converging region of the check slot. Similarly, the axially moveable structure may be axially moveable relative to the base shaft from the second position to the first position as the base shaft rotates about the longitudinal axis when the first pin is in the extended position to at least partially dispose the first pin in the control slot. In this arrangement, the first pin is configured to travel along at least a portion of the first side of the enlarged region in the check slot before entering the converging region of the check slot. It should be understood that the enlarged region of the control slot defines an enlarged width in the control slot and the converging region of the control slot defines a narrow width in the control slot, wherein the narrow width is less than the enlarged width. The aforementioned lobe sets are configured to rotate synchronously as the axially moveable structure rotates with the base shaft. With respect to the control module, the control module is in communication with the actuator to actuate at least one of the first and/or second pins to move between the retracted and extended positions in response to an input from the control module.

In yet another embodiment of the present disclosure, an engine assembly is provided that includes an internal combustion engine, and a camshaft assembly operatively coupled to a plurality of engine valves. The camshaft assembly includes a base shaft, an axially movable structure, a plurality of lobe sets, and a single actuator for each two cylinders. The base shaft extends along a longitudinal axis and rotates about the axis. The axially movable structure includes a cylindrical cam and a plurality of lobe sets. The axially movable structure is axially movable relative to the base shaft, but is still rotationally fixed to the base shaft. The cylindrical cam defines a control slot, wherein the control slot defines a single path around a circumference of the cylindrical cam. Optionally, the camshaft assembly may include only one cylindrical cam for each actuator. In the case of a single actuator, the actuator includes an actuator body and first and second pins, each movably coupled to the actuator body. The first and second pins are each movable relative to the actuator body between a retracted position and an extended position.

It will be appreciated that the aforementioned axially moveable structure may be axially moveable relative to the base shaft from a first position to a second position as the base shaft is rotated about the longitudinal axis when the second pin is in the extended position to at least partially dispose the second pin in the control slot. In this arrangement, the second pin is configured to travel along at least a portion of the second side of the enlarged region in the check slot before entering the converging region of the check slot. Similarly, the axially moveable structure may be axially moveable relative to the base shaft from the second position to the first position as the base shaft rotates about the longitudinal axis when the first pin is in the extended position to at least partially dispose the first pin in the control slot. In this arrangement, the first pin is configured to travel along at least a portion of the first side of the enlarged region in the check slot before entering the converging region of the check slot.

It should also be understood that the enlarged region of the control slot defines an enlarged width in the control slot and the converging region of the control slot defines a narrow width in the control slot, wherein the narrow width is less than the enlarged width. The aforementioned lobe sets are configured to rotate synchronously as the axially moveable structure rotates with the base shaft. With respect to the control module, the control module is in communication with the actuator to actuate at least one of the first and/or second pins to move between the retracted and extended positions in response to an input from the control module. The internal combustion engine of the foregoing embodiment includes a plurality of cylinders and a plurality of valves operatively coupled to the cylinders, wherein the valves are configured to control fluid flow in the cylinders.

The present disclosure and the specific features and advantages thereof will become more apparent based on the following detailed description and with reference to the accompanying drawings.

Drawings

These and other features and advantages of the present disclosure will become apparent based on the following detailed description, claims, and drawings, in which:

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

FIG. 2A is a schematic front view of a camshaft assembly of the engine assembly of FIG. 1, according to an exemplary, non-limiting embodiment of the present disclosure;

FIG. 2B is a schematic side view of the cylindrical cam of FIG. 2A;

FIG. 3 is a schematic view of an exemplary non-limiting camshaft assembly according to the present disclosure, wherein the camshaft assembly is in a first position; and

FIG. 4 is a schematic illustration of the exemplary non-limiting camshaft assembly of FIG. 3, 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

Reference will now be made in detail to presently preferred compositions, embodiments and methods of the present disclosure, which constitute the best modes of practicing the disclosure presently known to the inventors. The figures 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 how to variously employ the present disclosure.

Except in the examples, or where otherwise explicitly indicated, all numerical quantities in this description indicating amounts of material or states 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 limits specified is generally preferred. Additionally, unless expressly stated to the contrary: percentages, "parts," and ratios are by weight; the description of a group or class of substances as being suitable or preferred for a given purpose in connection with the present disclosure means that combinations of one or more members of the group or class are likewise suitable or preferred; the first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and applies mutatis mutandis to normal grammatical variations of the initially defined abbreviation; also, unless expressly stated to the contrary, a measure of a characteristic is determined by the same technique as previously or later recited for the same feature.

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 of the disclosure in any way.

It must also be noted that, as used in this 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 an element in the singular is intended to comprise a plurality of elements.

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

The phrase "consisting of" excludes any elements, steps, or components not specifically recited in the claims. The phrase "consisting essentially of" limits the scope of the claims to the specifically recited materials or steps, plus 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 alternatively. If one of these three terms is used, the presently disclosed and claimed subject matter may include the use of either of the other two terms.

Throughout this application, if publications are referenced, the entire 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.

Reference is made to the drawings, wherein like reference numerals correspond to like or similar parts throughout the several views; fig. 1 schematically illustrates a vehicle 10, such as a car, 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 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 Application Specific Integrated Circuits (ASICs), electronic circuits, central processing units (preferably microprocessors) and associated memory and storage devices (read-only, programmable read-only, random access, hard disk drive, etc.), combinational logic circuits, sequential logic circuits, input/output circuits and devices, suitable signal conditioning and buffer circuits, and other components that provide the described functionality. "software," "firmware," "programs," "instructions," "routines," "code," "algorithms," and similar terms mean any set of controller-executable instructions (including calibrations and look-up tables). The control module 16 may have a set of control routines that execute to provide desired functionality. The routines are executed by, for example, 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 regular intervals.

The internal combustion engine 14 includes an engine block 18 defining 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. 1 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 generally aligned along the engine axis E. Each cylinder 20A, 20B, 20C, and 20D is configured, shaped, and dimensioned to receive a piston (not shown). These pistons are configured to reciprocate inside 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, the air/fuel mixture is combusted in the combustion chambers 22A, 22B, 22C, and 22D, thereby driving the pistons in a reciprocating manner. By reciprocating the pistons, a crankshaft (not shown) operatively connected to wheels (not shown) of vehicle 10 may be driven. Rotation of the crankshaft may cause 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 for each combustion chamber 22A, 22B, 22C, and 22D. The internal combustion engine 14 includes intake ports 24, with at least one intake port 24 per cylinder 20A, 20B, 20C, 20D.

The internal combustion engine 14 further includes a plurality of intake valves 26 configured to control an inlet charge flow through the intake port 24. The number of intake valves 26 corresponds to the number of intake ports 24. Each intake valve 26 is at least partially positioned within a respective intake port 24. Specifically, each intake valve 26 is configured to move between an open state and a closed state along the corresponding intake port 24. In the open state, the intake valve 26 allows an inlet charge to enter the respective combustion chamber 22A, 22B, 22C, or 22D via the respective intake port 24. Conversely, in the closed state, the intake valve 26 prevents intake charge from entering the respective combustion chamber 22A, 22B, 22C, or 22D via the 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 utilize an ignition system (not shown) to combust an air/fuel mixture in the combustion chamber 22A, 22B, 22C, or 22D. This combustion produces exhaust gases. To exhaust these exhaust gases, the internal combustion engine 14 defines a plurality of exhaust ports 28. These exhaust ports 28 are in fluid communication with the combustion chambers 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 exhaust ports 28, with at least one exhaust port 28 per cylinder 20A, 20B, 20C, or 20D.

The internal combustion engine 14 further 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 positioned within a respective exhaust port 28. Specifically, each exhaust valve 30 is configured to move along the respective exhaust port 28 between an open state and a closed state. In the open state, the exhaust valves 30 allow exhaust gas to flow from the respective combustion chamber 22A, 22B, 22C, or 22D via the respective exhaust port 28. The vehicle 10 may include an exhaust system (not shown) configured to receive and process exhaust gases from the internal combustion engine 14. In the closed state, the exhaust valves 30 prevent exhaust gases from exiting the respective combustion chamber 22A, 22B, 22C, or 22D via the respective exhaust port 28.

As discussed in detail below, the intake valve 26 and the exhaust valve 30 (FIG. 1) may also be generally referred to as engine valves 66 (FIGS. 3-4) or simply "valves". Each valve 66 (fig. 3-4) is operatively coupled to or associated with a cylinder 20A, 20B, 20C, or 20D. Thus, the valve 66 (fig. 3-4) is configured to control the fluid flow to the respective cylinder 20A, 20B, 20C, or 20D (i.e., air/fuel mixture for the intake valve 26, exhaust for the exhaust valve 30). The valve 66 operatively coupled to the first cylinder 20A may be referred to as a first valve. The valve 66 operatively coupled to the second cylinder 20B may be referred to as a second valve. The valve 66 operatively coupled to the third cylinder 20C may be referred to as a third valve.

Referring to FIG. 1, the engine assembly 12 further includes a valve train 32 configured to control operation of the intake valve 26 and the exhaust valve 30. Specifically, the valve actuation system 32 may move the intake and exhaust valves 26, 30 between the open and closed states based at least in part on an operating condition of the internal combustion engine 14 (e.g., engine speed). The valve train 32 includes one or more camshaft assemblies 33 (see fig. 3-4) that are generally parallel to the engine axis E. In the illustrated embodiment, the valve train 32 includes two camshaft assemblies 33. One camshaft assembly 33 is configured to control operation of the intake valves 26, while the other camshaft assembly 33 may control operation of the exhaust valves 30. However, it is contemplated that the valve train 32 may include more or fewer camshaft assemblies 33.

Referring to fig. 3-4, in addition to the camshaft assembly 33, the valve train assembly 32 further includes a plurality of actuators 34A, 34B (e.g., solenoids) in communication with the control module 16. The actuators 34A, 34B may be electronically 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 the air distribution system 32. In the illustrated embodiment, the air distribution system 32 includes first and second actuators 34A, 34B. A first actuator 34A is operatively associated with the first and second cylinders 20A, 20B and is actuatable to control operation of the intake valves 26 of the first and second cylinders 20A, 20B. A second actuator 34B is operatively associated with the third and fourth cylinders 20C and 20D and is actuatable to control operation of the intake valves 26 of the third and fourth cylinders 20C and 20D. A third actuator 34C is operatively associated with the first and second cylinders 20A and 20B and is actuatable to control operation of the exhaust valves 30 of the first and second cylinders 20A and 20B. A fourth actuator 34C is operatively associated with the second and third cylinders 20C and 20D and is actuatable to control operation of the exhaust valves 30 of the second and third cylinders 20C and 20D. The actuators 34A, 34B and the control module 16 may be considered part of the camshaft assembly 33.

Referring to FIG. 2, the valve train 32 includes the camshaft assembly 33 and the actuators 34A, 34B as described above. The camshaft assembly 33 includes a base shaft 35 extending along a longitudinal axis X37. Thus, the base shaft 35 extends along the longitudinal axis X37. The base shaft 35 may also be referred to as a support shaft and includes a first shaft end 36 and a second shaft end 38 opposite the first shaft end 36.

Further, the camshaft assembly 33 includes a coupler (not shown) connected to the first shaft end 36 of the base shaft 35. The coupler may be used to operatively couple the base shaft 35 to a crankshaft (not shown) of the engine 14. The crankshaft of the engine 14 may drive a base shaft 35. Thus, the base shaft 35 may rotate about the longitudinal axis X37 when driven by, for example, a crankshaft of the engine 14. Rotation of the base shaft 35 causes the entire camshaft assembly 33 to rotate about the longitudinal axis X37, assuming the base shaft extends along the longitudinal axis X37. Thus, the base shaft 35 is operatively coupled to the internal combustion engine 14. The camshaft assembly 33 may additionally include one or more bearings (not shown), such as journal bearings, coupled to a stationary structure, such as the engine block 18. The bearings (not shown) may be spaced from each other along the longitudinal axis X.

The camshaft assembly 33 further includes one or more axially movable structures 44 mounted on the base shaft 35. The axially moveable structure 44 may also be referred to as a lobe pack assembly. The axially movable structure 44 is configured to move axially along a longitudinal axis X37 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 for maintaining angular alignment of the axially moveable structure 44 with the base shaft 35 and for transferring drive torque between the base shaft 35 and the axially moveable structure 44.

In the illustrated embodiment, the camshaft assembly 33 includes two axially moveable structures 44. It is contemplated that the camshaft assembly 33 may include more or fewer axially movable structures 44. The axially movable structures 44 are axially spaced from each other along the longitudinal axis X37, regardless of the amount. The axially movable structure 44 may also be referred to as "sliding members" because these members may slide along the base shaft 35.

With particular reference to fig. 3, each axially-movable structure 44 includes first, second, third, and fourth lobe sets 46A, 46B, 46C, 46D and a cylindrical cam coupled to one another. The first, second, third and fourth lobe sets 46A, 46B, 46C, 46D may also be referred to as cam sets. As mentioned above, in addition, each axially movable structure 44 includes only a single cylindrical cam 56. Each cylindrical cam 56 defines a control slot 60. Each axially moveable structure 44 may be a unitary structure. Thus, the first, second, third and fourth lobe sets 46A, 46B, 46C, 46D of the same axially movable structure 44 may be simultaneously movable relative to the base shaft 35. Nonetheless, the lobe sets 46A, 46B, 46C, 46D are rotationally fixed to the base shaft 35. Thus, the lobe sets 46A, 46B, 46C, 46D may rotate synchronously with the base shaft 35. Although the figures show each axially-movable structure 44 including four lobe sets 46A, 46B, 46C, 46D, it should be understood that each axially-movable structure 44 may include more or fewer lobe sets. Thus, each axially moveable structure may be mounted on the base shaft such that the axially moveable structure is axially moveable relative to the base shaft while the axially moveable structure is also rotationally fixed to the base shaft.

The first, second, third and fourth lobe sets 46A, 46B, 46C, 46D each include only one set of cam lobes 50. In each axially moveable structure 44, a cylindrical cam 56 may be disposed between the second and third lobe sets 46B, 46C. Each axially movable member 44 includes only one cylindrical cam 56. The cylindrical cam 56 is axially disposed between the third and fourth lobe sets 46C and 46D. The two sets of lobes 50 of the second and third sets of lobes 46B, 46C are axially spaced from one another. The first cam lobe has a first maximum lobe height and the second cam lobe has a second maximum lobe height. It should be appreciated that the first maximum lobe height is different than the second maximum lobe height.

As shown, the axially moveable structure includes a cylindrical cam and a plurality of lobe sets, wherein each lobe set further includes a plurality of cam lobes. The cylindrical cam defines a control slot defined by a single path 61 around a circumference 63 of the cylindrical cam, wherein the single path 61 is defined by an enlarged region 67 and a converging region 69. In contrast to conventional multi-path control slots, the control slot of the single path 61 is more reliable and durable in the operating state. It should be noted that a conventional multi-path slot may include a central protrusion that divides the path of the two control slots in the cylindrical cam, such that the protrusion is prone to cracking because the control pin transfers load to the central protrusion when it is guided into one of the two control slots.

Each set of cam lobes 50 includes a first cam lobe 54A and a second cam lobe 54B. The first and second cam lobes 54A, 54B are axially spaced relative to one another. The cam lobes 54A, 54B have a typical cam lobe type with profiles that define different valve lifts in two separate steps. The first and second cam lobes (54A and 54B, respectively) may have different lobe heights, as discussed in detail below. The cylindrical cam 56 in each axially moveable structure 44 includes a cylindrical cam body 58 and defines a control slot 60 extending into the cylindrical cam body 58.

Referring to fig. 3 and 4, each actuator 34A, 34B includes an actuator body 62A, 62B, and first and second pins 64A, 64B are movably coupled to the actuator bodies 62A, 62B. The first and second pins 64A, 64B of each actuator 34A, 34B are axially spaced from each other and are movable independently of each other. Specifically, each of the first and second pins 64A, 64B is movable between a retracted position 71 and an extended position 73 (fig. 1) relative to the respective actuator body 62A, 62B in response to an input or command from the control module 16. In the retracted position 71, the first or second pin 64A or 64B is not located in the control slot 60. Conversely, in the extended position 73, the first or second pin 64A or 64B may be at least partially disposed in the control slot 60. Thus, the first and second pins 64A, 64B may move toward the control slot 60 of the cylindrical cam 56 and away from the control slot 60 of the cylindrical cam 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 respective cylindrical cam 56 in a direction substantially perpendicular to the longitudinal axis X37.

Referring again to fig. 3-4, the actuator 34A, 34B includes an actuator body 62A, 62B, and the first and second pins 64A, 64B are each movably coupled to the actuator body 62A, 62B such that each of the first and second pins 64A, 64B is movable relative to the actuator body 62A, 62B between a retracted position 71 and an extended position 73, wherein the first and second pins 64A, 64B are configured to travel along a single path 61 defined by the control slot 60. The control module 16 is in communication with the actuators 34A, 34B such that each of the first and second pins 64A, 64B is configured to move between a retracted position 71 and an extended position 73 in response to an input 74 from the control module 16.

It should be appreciated that as the base shaft 35 rotates about the longitudinal axis 37, the axially moveable structure 44 may be axially moved relative to the base shaft 35 from a first position 75 (fig. 4) to a second position 77 (fig. 3), the second pin 64B is in the extended position 73, the second pin 64B is at least partially positioned in the control slot 60, and the second pin 64B is configured to travel along at least a portion 85 of the second side 80B of the enlarged region 67 in the control slot 60 prior to entering the converging region 69 of the control slot 60. Further, it should also be appreciated that as the base shaft 35 rotates about the longitudinal axis 37, the axially moveable structure 44 may be axially moveable relative to the base shaft 35 from a second position 77 (fig. 3) to a first position 75 (fig. 4), the first pin 64A is in an extended position 73, the first pin 64A is at least partially located in the control slot 60, and the first pin 64A is configured to travel along at least a portion 85 of the first side 80A of the enlarged region 67 in the control slot 60 before entering the converging region 69 of the control slot 60. Referring again to fig. 2-4, the enlarged region 67 of the control slot 60 defines an enlarged width 70 and the converging region 69 of the control slot 60 defines a narrow width 72 that is less than the enlarged width 70. The expanded width 70 gradually changes within the expanded region 67.

Thus, referring to fig. 3-4, an exemplary sliding camshaft assembly 33 according to the present disclosure includes: a base shaft 35, an axially moveable structure 44 having a cylindrical cam 56 and a plurality of lobe sets 46A, 46B, 46C, 46D, and actuators 34A, 34B. The base shaft 35 extends along a longitudinal axis 37, and the base shaft 35 may be configured to rotate about the longitudinal axis 37. The axially movable structure 44 is configured to move along the longitudinal axis 37 relative to the base shaft 35. However, the axially movable structure 44 is rotationally fixed to the base shaft 35. Each of the plurality of lobe sets 46A, 46B, 46C, 46D of the axially moveable structure 44 includes a plurality of cam lobes 54A, 54B. The cylindrical cam 56 in the axially moveable structure 44 defines a control slot 60 defined by a single path 61 around a circumference 63 of the cylindrical cam 56, whereby the single path 61 is defined by an enlarged region 67 and a converging region 69. The actuator 34A, 34B includes an actuator body 62A, 62B along with first and second pins 64A, 64B that are each movably coupled to the actuator body 62A, 62B such that each of the first and second pins 64A, 64B is movable relative to the actuator body 62A, 62B between a retracted position 71 and an extended position 73. The first and second pins 64A, 64B are configured to travel along a single path 61 defined by the control slot 60. However, the axially moveable structure 44 may be axially moveable relative to the base shaft 35 from a first position 75 (fig. 4) to a second position 77 (fig. 3) when the base shaft 35 is rotated about the longitudinal axis 37, and the second pin 64B is in the extended position 73, wherein the second pin 64B is at least partially disposed in the control slot 60. In this arrangement, the second pin 64B is configured to travel along at least a portion 85 of the second side 80B of the enlarged region 67 in the check slot 60 before entering the converging region 69 of the check slot 60. Similarly, when the base shaft 35 is rotated about the longitudinal axis 37, the axially moveable structure 44 may be moved axially relative to the base shaft 35 from the second position 77 (fig. 3) to the first position 75 (fig. 4) with the first pin 64A in the extended position 73 such that the first pin 64A is at least partially positioned in the control slot 60. In this arrangement, the first pin 64A is configured to travel along at least a portion 85 of the first side 80A of the enlarged region 67 in the check slot 60 before entering the converging region 69 of the check slot 60. As shown in fig. 2A, it should be appreciated that the enlarged region 67 of the control slot 60 defines an enlarged width 70 in the control slot 60, and the converging region 69 of the control slot 60 defines a narrow width 72 in the control slot 60, wherein the narrow width 72 is less than the enlarged width 70. The expanded width 70 gradually changes within the expanded region 67.

Referring to fig. 1, 3, and 4, the control module 16 may be in communication with the actuators 34A, 34B to actuate the first and/or second pins 64A, 64B such that the first and/or second pins 64A, 64B may move between the retracted position 71 and the extended position 73 in response to an input 74 from the control module 16. Further, with respect to the plurality of cam lobes 54A, 54B defined on the axially moveable structure 44 (within each of the lobe sets 46A-46D), such cam lobes 54A, 54B may include at least a first cam lobe 54A and a second cam lobe 54B axially spaced relative to each other. First cam lobe 54A has a first maximum lobe height 76 and second cam lobe 54B has a second maximum lobe height 78. The first maximum lobe height 76 may be different than the second maximum lobe height 78 in order to vary the displacement of the valve.

In yet another embodiment of the present disclosure, an engine assembly 12 (fig. 1) is provided that includes an internal combustion engine 14, a camshaft assembly 33, and actuators 34A, 34B, see fig. 3-4. As shown in fig. 1, 3, and 4, internal combustion engine 14 may include: a first cylinder 20A, a second cylinder 20B, a first valve 66A operatively coupled to the first cylinder 20A, and a second valve 66B operatively coupled to the second cylinder 20B. The first valve 66A may be configured to control fluid flow in the first cylinder 20A while the second valve 66B is configured to control fluid flow in the second cylinder 20B. The camshaft assembly 33 includes a base shaft 35 and an axially movable structure 44. The base shaft 35 rotates about a longitudinal axis 37 (and extends along the longitudinal axis 37). The axially moveable structure 44 may be mounted on the base shaft 35 such that the axially moveable structure 44 is axially moveable relative to the base shaft 35 along the longitudinal axis 37. However, the axially movable structure 44 is rotationally fixed to the base shaft 35. The axially movable structure 44 includes a plurality of lobe sets 46A, 46B, 46C, 46D and a cylindrical cam 56. Each of lobe sets 46A-46D includes a plurality of cam lobes 54A, 54B. Each of the lobe sets 46A-46D (a plurality of cam lobes 54A, 54B) includes first and second cam lobes 54A, 54B that are axially spaced relative to one another. Each first cam lobe 54A has a first maximum lobe height 76 and each second cam lobe 54B has a second maximum lobe height 78. The first maximum lobe height 76 may be different than the second maximum lobe height 78.

As shown in fig. 2A, the cylindrical cam 56 of the axially moveable structure 44 defines a control slot 60, the control slot 60 being a single path 61 around a circumference 63 (fig. 2B) of the cylindrical cam 56. The aforementioned single path 61 is defined by an expansion region 67 and a convergence region 69. With respect to the actuators 34A, 34B, 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. Each of the first and second pins 64A, 64B moves relative to the actuator body 62A, 62B between a retracted position 71 and an extended position 73 such that each of the first and second pins 64A, 64B is configured to travel along the single path 61 defined by the control slot 60.

However, when the second pin 64B is in the extended position 73 such that the second pin 64B is at least partially located in the control slot 60, the axially moveable structure 44 may be axially moved relative to the base shaft 35 from a first position 75 (fig. 4) to a second position 77 (fig. 3) as the base shaft 35 is rotated about the longitudinal axis 37. In this arrangement, the second pin 64B is configured to travel along at least a portion 85 of the second side 80B of the enlarged region 67 in the check slot 60 before entering the converging region 69 of the check slot 60. Similarly, when the first pin 64A is in the extended position 73 such that the first pin 64A is at least partially disposed in the control slot 60, the axially moveable structure 44 may be axially moveable relative to the base shaft 35 from the second position 77 to the first position 75 as the base shaft 35 is rotated about the longitudinal axis 37. In this arrangement, the first pin 64A is configured to travel along at least a portion 85 of the first side 80A of the enlarged region 67 in the check slot 60 before entering the converging region 69 of the check slot 60. Referring again to fig. 2A, it should be appreciated that the enlarged region 67 of the control slot 60 defines an enlarged width 70 in the control slot 60, and the converging region 69 of the control slot 60 defines a narrow width 72 in the control slot 60, wherein the narrow width 72 is less than the enlarged width 70. The expanded width 70 gradually changes within the expanded region 67. The aforementioned lobe sets 46A, 46B, 46C, 46D are configured to rotate synchronously when the axial moving structure 44 rotates together with the base shaft 35, see fig. 3 to 4. With respect to the control module 16 (fig. 1), the control module 16 communicates with the actuators 34A, 34B (fig. 3-4) to actuate movement of at least one of the first and/or second pins 64A, 64B between the retracted position 71 and the extended position 73 in response to an input 74 from the control module 16.

In yet another embodiment of the present disclosure, an engine assembly 12 (fig. 1) is provided that includes an internal combustion engine 14 and a camshaft assembly 33 operatively coupled to a plurality of engine valves 66. As shown in fig. 3 to 4, the camshaft assembly 33 includes: a base shaft 35, an axially movable structure 44, a plurality of lobe sets 46A, 46B, 46C, 46D, and a single actuator 34A, 34B for each two cylinders 20A, 20B, 20C, 20D. The base shaft 35 extends along and rotates about a longitudinal axis 37. The axially movable structure 44 includes a cylindrical cam 56 and a plurality of lobe sets 46A, 46B, 46C, 46D. The axially movable structure 44 is axially movable relative to the base shaft 35 but is still rotationally fixed to the base shaft 35. As shown in fig. 2A, the cylindrical cam 56 defines a control slot 60, wherein the control slot 60 defines a single path 61 (fig. 2B) around a circumference 63 of the cylindrical cam 56. Optionally, the camshaft assembly 33 may include only one cylindrical cam 56 per actuator 34A, 34B. With respect to a single actuator 34A, 34B, the actuator 34A, 34B includes an actuator body 62A, 62B and first and second pins 64A, 64B that are each movably coupled to the actuator body 62A, 62B. Each of the first and second pins 64A, 64B is movable relative to the actuator body 62A, 62B between a retracted position 71 and an extended position 73.

It should be appreciated that when the second pin 64B is in the extended position 73 such that the second pin 64B is at least partially disposed in the control slot 60, the aforementioned axially moveable structure 44 may be axially moved relative to the base shaft 35 from a first position 75 (fig. 4) to a second position 77 (fig. 3) as the base shaft 35 is rotated about the longitudinal axis 37. In this arrangement, the second pin 64B is configured to travel along at least a portion 85 of the second side 80B of the enlarged region 67 in the check slot 60 before entering the converging region 69 of the check slot 60. Similarly, when the first pin 64A is in the extended position 73 such that the first pin 64A is at least partially disposed in the control slot 60, the axially moveable structure 44 may be axially moved relative to the base shaft 35 from the second position 77 (fig. 3) to the first position 75 (fig. 4) as the base shaft 35 is rotated about the longitudinal axis 37. In this arrangement, the first pin 64A is configured to travel along at least a portion 85 of the first side 80A of the enlarged region 67 in the check slot 60 before entering the converging region 69 of the check slot 60.

Referring again to fig. 2A, it should also be appreciated that the enlarged region 67 of the control slot 60 defines an enlarged width 70 in the control slot 60 and the converging region 69 of the control slot 60 defines a narrow width 72 in the control slot 60, wherein the narrow width 72 is less than the enlarged width 70. The expanded width 70 gradually changes within the expanded region 67. The aforementioned lobe sets 46A, 46B, 46C, 46D are configured to rotate synchronously as the axially moveable structure 44 rotates with the base shaft 35. With respect to the control module 16 (fig. 1), the control module 16 communicates with the actuators 34A, 34B to actuate movement of at least one of the first and/or second pins 64B between the retracted position 71 and the extended position 73 in response to an input 74 from the control module 16. The internal combustion engine 14 (FIG. 1) of the foregoing embodiment includes a plurality of cylinders 20A-20D and a plurality of valves 66 operatively coupled to the cylinders 20A-20D, wherein the valves 66 are configured to control fluid flow in the cylinders 20A-20D.

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.