Engine valve system with rocker arm assembly having roller lock for selective deactivation of engine valve

Abstract

A rocker arm assembly for an engine valve system includes a rocker arm for actuating an engine valve, a stop, a biasing member, and a swing lock attached to one of a valve end or a cam end of the rocker arm and defining a pivot axis and including an actuation surface. The actuation surface is rotatable between a stop orientation and an idle orientation, and the biasing member biases the swing lock toward the stop orientation in which the swing lock is in contact with the stop and is constrained between the rocker arm and one of the engine valve and cam. The swing lock is movable in an opposite direction from the biasing member bias to disable the engine valve.

Description

Technical Field

[0001] The present invention generally relates to a rocker arm assembly for an engine valve system, and more specifically to a rocker arm assembly having a swing lock that is rotatable between a stop orientation for actuating a relevant engine valve and an idle orientation for deactivating an engine valve. Background Technology

[0002] Various valve actuation systems are known in the field of internal combustion engines. In a common design, the camshaft rotates via a camshaft gear in the engine gear train. The rotation of the camshaft causes a non-circular cam lobe on the cam to rotate and contact the components that open and close the engine valves (e.g., exhaust and intake valves). Some designs employ valve tappets that include a pushrod extending between the camshaft and a rocker arm, which is supported for reciprocating motion in or on the engine head. Other designs position the camshaft such that the cam lobe directly contacts the rocker arm. The rocker arm typically reciprocates against a valve return spring to actuate and open the engine valve.

[0003] In some situations, it may be necessary to deactivate engine valves. Deactivating engine valves has been widely used for so-called engine braking for many years. In a typical example, the engine valves close so that the pistons, reciprocating in the engine, compress and burn the fluid in the cylinders, rather than expelling that fluid from the cylinders. Deactivating a single cylinder requires additional work to reduce or otherwise control engine speed, thus increasing rotational resistance to the engine crankshaft.

[0004] Existing engine braking systems can be relatively complex and expensive, requiring multiple moving parts within the engine valve train that can disconnect mechanical connections when needed and then re-establish those connections as required. Cotton's U.S. Patent No. 6,644,271 relates to an engine braking system for a multi-cylinder engine. In Cotton's disclosure, valve actuators are apparently configured to be alternately fluidically connected to a low-pressure fluid source or an engine fluid reservoir. A brake control valve is operatively connected to some of the valve actuators and is movable between a first position, in which the valve actuator is connected to the reservoir and blocked from the low-pressure fluid, and in a second position, in which the valve actuator is connected to the low-pressure fluid and blocked from the reservoir. Cotton's patent may have various applications, but there is always room for improvement and development of alternative strategies in this field. Summary of the Invention

[0005] In one aspect, a rocker arm assembly for an engine valve system includes a rocker arm for actuating an engine valve and includes a valve end, a cam end, and a shaft bore. The shaft bore defines a bore center axis and is formed between the valve end and the cam end to receive a rocker arm shaft supporting reciprocating motion of the rocker arm. The rocker arm assembly also includes a stop and a swing lock attached to one of the valve end or the cam end of the rocker arm and including a retainer and an actuating surface. The retainer defines a pivot axis oriented parallel to the bore center axis. The rocker arm assembly also includes a biasing member. The actuating surface is supported by the retainer at a location spaced apart from the pivot axis and is rotatable with the retainer between a stop orientation and a free-spinning orientation about the pivot axis. The biasing member biases the swing lock toward the stop orientation such that the swing lock contacts the stop to confine the swing lock between the rocker arm and one of the engine valve or the cam, and the swing lock is movable in the opposite direction to the biasing member toward the free-spinning orientation.

[0006] In another aspect, an engine valve system includes a cam rotatable about a cam axis, an engine valve, and a rocker arm. The rocker arm includes a valve end, a cam end, and a shaft bore formed between the valve end and the cam end. The rocker arm shaft is located in the shaft bore and supports the rocker arm to reciprocate in response to cam rotation. The engine valve system also includes a swing lock that defines a pivot axis and includes an actuating surface. The swing lock is rotatable relative to the rocker arm about the pivot axis between a stop orientation and a free-spinning orientation. In the stop orientation, the swing lock is confined between the rocker arm and either the engine valve or the cam, such that the actuating surface transmits reciprocating motion between the rocker arm and the respective engine valve or cam, thereby actuating the engine valve. In the free-spinning orientation, the swing lock is not confined between the rocker arm and the respective engine valve or cam, such that the actuating surface does not transmit reciprocating motion, thereby disengaging the engine valve.

[0007] In another aspect, a method for operating an engine valve system includes reciprocating a rocker arm based on rotation of a cam in the engine valve system, and opening and closing engine valves in the engine valve system based on the reciprocating motion of the rocker arm. The method also includes rotating a swing lock about a pivot axis from a stop orientation to a freewheeling orientation, in which an actuating surface in the swing lock transmits the reciprocating motion between the rocker arm and either the engine valve or the cam. The method further includes deactivating the engine valve based on rotation of the swing lock to the freewheeling orientation. Attached Figure Description

[0008] Figure 1 This is a side cross-sectional view of an engine system including an engine valve system according to one embodiment;

[0009] Figure 2 This is a perspective view of a rocker arm assembly according to one embodiment;

[0010] Figure 3 This is a schematic view of an engine valve system in an actuated configuration according to one embodiment;

[0011] Figure 4 This is a schematic view of an engine valve system in a decommissioned configuration according to one embodiment;

[0012] Figure 5 This is a schematic view of an engine valve system in an actuated configuration according to another embodiment; and

[0013] Figure 6 This is a schematic view of an actuation system for a rocker arm assembly in an engine valve system according to one embodiment. Detailed Implementation

[0014] See Figure 1 The diagram illustrates an internal combustion engine system 10 according to one embodiment, including a cylinder block 12 in which a combustion cylinder 16 is formed. Typically, in a four-stroke engine cycle, a piston 18 is movable within the cylinder 16 between a bottom dead center (BDC) position and a top dead center (TDC) position. An engine cylinder head 14 is coupled to the cylinder block 12 and has an intake manifold 24 and an exhaust manifold 26 formed therein to deliver air, or air possibly mixed with fuel and / or exhaust gases, to the cylinder 16 and to deliver exhaust gases out of the cylinder 16, respectively. A plurality of engine valves 20 are shown supported in the engine cylinder head 14 and may include an exhaust valve or an intake valve for controlling fluid communication between the cylinder 16 and one of the intake manifold 24 or the exhaust manifold 26. In the illustrated embodiment, the engine valve 20 includes an exhaust valve coupled to a valve cross arm 22 and configured to open against the biasing force of a return spring 21, allowing the piston 18 to expel combustion exhaust gases into the exhaust manifold 26. When engine valve 20 is closed, and one or more intake valves are also closed, piston 18 can compress the fluid in cylinder 16 to an auto-ignition threshold known in the art. As will further become apparent from the following description, one practical application of the invention is envisioned as engine braking, where engine valve 20 is sometimes kept closed, forcing piston 18 to compress the fluid in cylinder 16 during engine cycles without combustion, thereby slowing the engine system 10 based on well-known principles and the work required to compress the fluid in cylinder 16.

[0015] Engine system 10 also includes engine valve system 30, of which engine valve 20 is a part. Valve system 30 also includes camshaft 32, which includes one or more cams 34 and is rotatable about camshaft axis 36. Engine valve system 30 also includes rocker arm assembly 38, which includes rocker arm 40 for actuating one or more engine valves (including engine valve 20 in the illustrated embodiment). Rocker arm assembly 38 may be one of a plurality of similarly constructed rocker arm assemblies, and each rocker arm assembly is associated with one or more engine valves for a cylinder in engine system 10. Rocker arm 40 includes a valve end 42, a cam end 44, and a bore 46 defining a bore center axis 48. Bore 46 is formed between valve end 42 and cam end 44 and receives a rocker arm shaft located in bore 46 and supports rocker arm 40 in reciprocating motion in response to rotation of cam 34. In the illustrated embodiment, the rocker arm assembly 38 includes a cam follower 70 that rotates in contact with a cam 34, the cam 34 having a non-cylindrical shape for inducing reciprocating motion of the rocker arm 40 according to known principles. As described above, the rocker arm assembly 38 may be one of a plurality of rocker arm assemblies, wherein each cylinder 16 in the engine system 10 is associated with an intake valve rocker arm, an exhaust valve rocker arm, and possibly a fuel injector rocker arm. The engine system 10 may include a compression ignition engine as described above; however, the invention is not limited thereto, and spark ignition engines or pre-combustion chamber ignition engines are also included within the scope of the invention. The engine system 10 may include any number of combustion cylinders in any suitable arrangement.

[0016] See now Figure 2 The rocker arm 40 includes an upper surface 66 and a lower surface 68, each extending between the valve end 42 and the cam end 44. The swing lock 52 is attached to either the valve end 42 or the cam end 44. Figure 1 and Figure 2In the illustrated embodiment, the valve is attached to valve end 42. In some embodiments, clearance adjustment mechanism 72 may be coupled to valve end 52. The swing lock 52 includes a roller retainer or retainer 54 supported in rocker arm 40 and defining a pivot axis 56 oriented parallel to bore center axis 48. In the illustrated embodiment, pivot axis 56 extends through rocker arm 40. The swing lock 52 also includes an actuating surface 57. Actuating surface 57 may include an arcuate surface and is shaped and positioned to contact the upper surface 37 of valve crossarm 22, or to contact an intermediate surface located between valve crossarm 22 and rocker arm 40. Actuating surface 57 may also be shaped and positioned to contact tappets, valve stems, or other structures thereof, or other structures associated therewith, of one or more engine valves. Actuating surface 57 is supported by retainer 54 at a location spaced apart from pivot axis 56. The swing lock 52 (and including actuating surface 57 and retainer 54) is capable of... Figure 1 and Figure 2 The illustrated rotation occurs between a stop orientation and an idle orientation about the pivot axis 56. In the stop orientation, the swing lock 52 contacts the stop member 58, and the swing lock 52 is confined between the rocker arm 40 and one of the engine valves 20 or the cam 34. In the illustrated embodiment, in the stop orientation, the swing lock 52 is confined between the rocker arm 40 and both engine valves 20. Confining it therein does not require the swing lock 52 to physically contact the engine valves; rather, the swing lock 52 is held in place within the interconnecting components of the engine valve system 30, such that the actuating surface 57 transmits reciprocating motion between the rocker arm 40 and the respective engine valve 20 or the cam 34. In the illustrated configuration, the engine valve 20 is actuated. As discussed further herein, in the idle orientation, the swing lock 52 is not confined between the rocker arm 40 and the respective engine valve 20 or the cam 34, such that the actuating surface 57 does not transmit reciprocating motion, thereby deactivating the engine valve 20.

[0017] Also in the illustrated embodiment, the retainer 54 includes a fork-shaped member, and the swing lock 52 includes a roller 62 that defines a roller axis 64 and has an actuating surface 57 formed thereon. The rocker arm assembly 38 also includes a biasing member 60 that biases the swing lock 52 toward a stop orientation. Therefore, the swing lock 52 is capable of moving toward a free-spinning orientation against the biasing or biasing force of the biasing member 60. The biasing member 60 may include a biasing spring residing in the rocker arm 40. The rocker arm assembly 38 also includes a fluid actuator 76 configured to rotate the swing lock 52 about a pivot axis 56 from the stop orientation toward a free-spinning orientation against the biasing force generated by the biasing member 60. When the actuator 76 is reversed or deactivated, the biasing member 60 may push the swing lock 52 back to the stop orientation.

[0018] See also Figure 3The diagram illustrates an engine valve system 30 and a rocker arm assembly 38 with the shown additional functions and structural features. A retainer 54 may include a pivot end 82 generally positioned within the rocker arm 40, and a roller end 84. A biasing member 60 may be operably coupled to the pivot end 82 of the retainer 54. A pivoting path defined by the roller axis 64 between a stop orientation and a freewheeling orientation extends between the rocker arm 40 and the engine valve 20, or in other embodiments between the rocker arm and the cam. Figure 3 It can also be seen that the actuator 76 is coupled to the roller end 84. The actuator 76 may contact the retainer 54 or the roller 62. The actuator 76 includes an actuator pin 80, and therefore in some embodiments and as further discussed herein, the actuator 76 may include a fluid-actuated pin actuator. Figure 1 In this context, for this purpose, the hydraulic actuation system 78 is shown as being connected to the actuator 76.

[0019] For example Figure 3 As shown, the fixed plane 90 is defined by the hole center axis 36 and the pivot axis 56, and includes each of the hole center axis 36 and the pivot axis 56. The movable plane 92 is defined by the roller axis 64 and the pivot axis 56, and includes each of the roller axis 64 and the pivot axis 56. Figure 3 The diagram also shows the valve reciprocating axis 23 and the vertical plane 96. During operation, the rocker arm 40 reciprocates approximately up and down, while the vertical plane 96 remains approximately parallel to the valve reciprocating axis 23. The moving plane 92 will change its orientation relative to the fixed plane 90, as well as relative to the vertical plane 96 and the valve reciprocating axis 23. Figure 3 In this configuration, the moving plane 92 extends upward and outward on the rocker arm 40, and the swing lock 52 tilts downward and inward in a direction approximately toward the center of the rocker arm 40. The closing bias of the valve return spring 21, in conjunction with the bias member 60, tends to keep the roller 62 firmly held on the stop member 58. Figure 2 As shown, the stop 58 can be formed by the downward protrusion 74 of the rocker arm 40, such that the stop 58 forms part of the lower surface 68 of the rocker arm, and the roller 62 and the actuating surface 57 contact the lower surface 68 of the rocker arm in a stop orientation. Figure 3 As shown, in the stop orientation, an angle 98 is formed between the vertical plane 96 and the moving plane 92. Another angle 94, defined by the moving plane 92 and the fixed plane 90, is formed between the moving plane 92 and the fixed plane 90. In the stop orientation, angle 94 is the acute angle between planes 90 and 92. Angle 98 is also an acute angle, opening upwards relative to the rocker arm 40, and in some embodiments may be in the range of 1° to 5°, more specifically in the range of 1° to 3°.

[0020] See also Figure 4 The image shows the engine valve system 30 and rocker arm assembly 38, which may appear when the swing lock 52 has been adjusted to idle orientation. The actuator 76 can be operated to push the pin 80, contacting the retainer 54 or roller 62, for example, causing the moving plane 92 relative to the rocker arm 40 from... Figure 2 The orientation rotation is shown. Angle 98 can be an acute angle relative to the idle orientation, opposite to the sign of the stop orientation, and roller 62 now moves away from stop 58 and is no longer restricted between rocker arm 40 and engine valve 20. Figure 4 The swing lock 52 shown does not transmit the reciprocating motion between the rocker arm 40 and the engine valve 20. Instead, the rocker arm 40 continues to reciprocate based on the rotation of the cam 34, but the swing lock 52 will idle or passively reciprocate within an angle range of 100 while the engine valve 20 remains closed. A pivot pin hole 86 formed in the valve end 42 of the rocker arm 40 is also shown. The pivot pin 88 of the swing lock 52 is within the pivot pin hole 86 and attached to the retainer 54, thereby defining the pivot axis 56. It should be remembered that the bias member 60 may reside in the rocker arm 40, and the actuator 76 may reside in the rocker arm 40 or be attached separately to the rocker arm 40. In an alternative configuration, the positions of the bias member 60 and the actuator 76 may be interchanged relative to the positions shown. Either or both of the bias member 60 and the actuator 76 may be located within the rocker arm 40 or attached to the outside of the rocker arm 40.

[0021] See now Figure 5 The diagram illustrates an engine valve system 130 according to another embodiment, including a rocker arm assembly 138. The rocker arm assembly 138 includes a rocker arm 140 having a valve end 142 and a cam end 144. The rocker arm 140 can be configured similarly to the embodiment described above, but instead of a rocker lock attached to the valve end, a rocker lock 152 is attached to the cam end 144 of the rocker arm 140. The rocker lock 152 includes a retainer 154 that supports a roller 162 in a manner substantially similar to the retainer 52 described above. Figure 5As shown, biasing member 160 biases the swing lock 152 toward the stop orientation, and actuator 176 is provided to rotate the swing lock 152 toward the idle orientation against the biasing force generated by biasing member 160. In the stop orientation, the swing lock 152 is confined between rocker arm 140 and cam 134, such that reciprocating motion is transmitted between rocker arm 140 and cam 134. Therefore, when the swing lock 152 is in the stop orientation, rotation of cam 134 causes rocker arm 140 to reciprocate to open and close engine valve 120. A vertical plane defined similarly to the above embodiment is shown at 196. A plane of movement defined similarly to the above embodiment is shown at 192. Angle 198 is defined by plane 196 and plane 192. Actuator 176 can be operated to rotate the swing lock 152 to the idle orientation, such that rocker arm 140 stops reciprocating motion in response to rotation of cam 134, thereby deactivating engine valve 120. Actuator 176 can be reversed or deactivated to enable bias member 160 to push swing lock 152 from free-spinning orientation back to stop orientation, as is the case in rocker arm assembly 38. Features and functions of rocker arm assembly 138, not specifically described, are to be understood as similar to those of other embodiments described herein.

[0022] See now Figure 6 The actuation system 78, shown in further detail, is illustrated. Pin 80 is shown in contact with the swing lock 52 and supported in the rocker arm 40. A fluid chamber is shown at 77 and receives fluid flow from the hydraulic tank 73 via a pump 81 and a check valve 83. A solenoid-operated shut-off valve 85 is shown, which may be normally open. During normal operation, pump 81 can pump hydraulic fluid into chamber 77, which is returned to tank 73 via solenoid valve 85. When it is desired to adjust the swing lock 52 from the stop orientation to the idle orientation to deactivate the engine valves, shut-off valve 85 can be actuated to prevent fluid from flowing out of chamber 77, thus creating pressure to drive pin 80 to linearly adjust the swing lock 52, as described herein. When it is desired to return the swing lock 52 to the stop orientation to reactivate the engine valves, shut-off valve 85 can be opened, and pin 80 will move linearly, for example with the aid of a return spring 87, allowing the swing lock 52 to return to the stop orientation.

[0023] Industrial applicability

[0024] Usually refer to the accompanying drawings, but especially refer to... Figures 1 to 4 In one embodiment, operating the engine valve system 30 may include reciprocating a rocker arm 40 based on rotation of a cam 34 in the engine valve system 30. One or more engine valves 20 may be opened and closed in the engine valve system 30 based on the reciprocating motion of the rocker arm 40. This typically occurs when the rocker lock 52 is in the stop orientation, transmitting the reciprocating motion between the rocker arm 40 and the engine valve 20. Figure 5In the embodiment where the rocker arm 140 is in the stop orientation, the actuating surface of the roller 162 transmits reciprocating motion between the rocker arm 140 and the cam 134, thereby causing the rocker arm 140 to reciprocate. To deactivate the engine valve 20, as discussed herein, the swing lock 52 rotates about the pivot axis 57 from the stop orientation to the idle orientation. With the swing lock 52 in place, the idle rocker arm 40 can continue to reciprocate, but will not transmit reciprocating motion to the engine valve 20. Figure 5 In the case of the embodiment, rocker arm 140 will not reciprocate in response to rotation of cam 134. In either case, the relevant engine valve remains closed, thereby allowing the engine system, and in particular the relevant cylinder in the engine system, to be braked based on the deactivation of the main engine valve.

[0025] This specification is for illustrative purposes only and should not be construed as limiting the scope of the invention in any way. Therefore, those skilled in the art will understand that various modifications can be made to the currently disclosed embodiments without departing from the full and reasonable scope and spirit of the invention. Other aspects, features, and advantages will become apparent from a study of the accompanying drawings and appended claims. As used herein, the articles “a” and “an” are intended to include one or more items and are used interchangeably with “one or more.” The term “an” or similar language is used where only one item is desired. Furthermore, as used herein, the terms “have,” “possess,” “with,” etc., are intended to be open-ended terms. Additionally, the phrase “based on” is intended to mean “at least partially based on” unless otherwise explicitly stated.

Claims

1. A rocker arm assembly for an engine valve system, comprising: A rocker arm for actuating an engine valve and including a valve end, a cam end, and a shaft hole, the shaft hole defining a bore center axis and formed between the valve end and the cam end to receive a rocker arm shaft that supports the rocker arm in reciprocating motion. Stopping components; A rocker lock is attached to one of the valve end or the cam end of the rocker arm and includes a retainer and an actuating surface. The retainer defines a pivot axis oriented parallel to the central axis of the bore and includes a fork-shaped member. The rocker lock includes a roller that defines a roller axis and has the actuating surface formed thereon. The rocker arm includes a pivot pin hole formed in one of the valve end or the cam end and includes a pivot pin located within the pivot pin hole and attached to the retainer. Offset component; The actuating surface is supported by the retainer at a position spaced apart from the pivot axis, and is able to rotate together with the retainer between a stop orientation and an idle orientation about the pivot axis; and The biasing member biases the swing lock toward the stop orientation such that the swing lock contacts the stop member to restrict the swing lock between the rocker arm and one of the engine valve or the cam via the biasing force of the biasing member, and the swing lock is movable in the opposite direction to the biasing force of the biasing member toward the idling orientation.

2. The component according to claim 1, wherein: The component also includes an actuator configured to rotate the swing lock about the pivot axis from the stop orientation toward the idle orientation against the bias force.

3. The component according to claim 2, wherein: A fixed plane is defined by the central axis of the hole and the pivot axis, and the fixed plane includes each of the central axis of the hole and the pivot axis; A plane of movement is defined by the roller axis and the pivot axis, and the plane of movement includes each of the roller axis and the pivot axis; The fixed plane and the moving plane define an acute angle between them in the stop orientation of the swing lock; The retainer includes a pivot end and a roller end, and the biasing member is operably coupled to the pivot end of the retainer. and The biasing element includes a biasing spring residing in the rocker arm.

4. An engine valve system, comprising: A cam, which is rotatable about a cam axis; Engine valves; A rocker arm, the rocker arm including a valve end, a cam end, and a shaft hole formed between the valve end and the cam end; A rocker arm shaft, which is positioned in the shaft hole and supports the rocker arm to reciprocate in response to the rotation of the cam; A swing lock that defines a pivot axis and includes an actuating surface, and the swing lock is rotatable about the pivot axis relative to the rocker arm between a stop orientation and an idle orientation; In terms of stopping orientation, the swing lock is restricted between the rocker arm and one of the engine valve or the cam, such that the actuating surface transmits reciprocating motion between the rocker arm and the corresponding one of the engine valve or the cam, thereby actuating the engine valve; and In the idling orientation, the swing lock is not restricted between the rocker arm and either the engine valve or the cam, so that the actuating surface does not transmit the reciprocating motion, thereby disabling the engine valve. The swing lock also includes a roller retainer defining the pivot axis, and a roller supported in the roller retainer to rotate about the pivot axis, the roller defining a roller axis and having the actuating surface formed thereon; The engine valve system also includes a biasing member that biases the swing lock toward the stop orientation, and the rocker arm also includes a stop member that contacts the swing lock in the stop orientation; The idling orientation is one of a plurality of idling orientations that define an angular range around the pivot axis, and the swing lock is capable of rotating around the pivot axis within the angular range.

5. The system according to claim 4, wherein: The roller axis is defined as a pivoting path between the stop orientation and the idle orientation, the pivoting path extending between the rocker arm and a corresponding one of the engine valves or cams.

6. The system according to claim 4 or 5, wherein: The swing lock is attached to the cam end of the rocker arm and is restricted in the stop orientation between the rocker arm and the cam.

7. The system according to claim 4 or 5, wherein: The swing lock is attached to the valve end of the rocker arm and is restricted in the stop orientation between the rocker arm and the engine valve.

8. The system of claim 4 or 5, further comprising an actuator configured to counteract the biasing force of the biasing member, causing the oscillating lock to rotate about the pivot axis from the stop orientation toward the idle orientation; and The actuator includes a fluid-actuated pin actuator.

9. A method for operating an engine valve system according to any one of claims 4-8, comprising: The rocker arm reciprocates based on the rotation of the cam in the engine valve system. The reciprocating motion of the rocker arm opens and closes the engine valves in the engine valve system. The swing lock is rotated about a pivot axis from a stop orientation to an idle orientation, in which the actuating surface in the swing lock transmits reciprocating motion between the rocker arm and one of the engine valve or the cam. as well as The engine valves are deactivated based on the rotation of the swing lock to the idling orientation.

10. The method of claim 9, further comprising deactivating the engine based on the engine valves, wherein: In the stop orientation, the swing lock is restricted between the rocker arm and a corresponding one of the engine valve or the cam, and rotation of the swing lock includes rotating the swing lock against the biasing force of the biasing member from the stop orientation; and The rotation of the swing lock includes rotating the swing lock based on the application of an actuating force, which is applied to the swing lock via a fluid actuator.

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