HYDRAULIC CAPSULE FOR HYDRAULIC PLAY COMPENSATION

Abstract

A rocker arm assembly includes an engine brake capsule assembly. The engine brake capsule assembly is movable between a retracted position and an extended position. The engine brake capsule assembly comprises a body that includes a lower chamber and an upper chamber. The engine brake capsule assembly further includes a plunger that is partially located in the lower chamber, the plunger comprising an outer shoulder located on one side of the plunger and a locking pin configured to extend into the lower chamber and engage with the outer shoulder of the plunger.The motor brake capsule assembly further comprises an actuating pin located in the upper chamber and extending downwards into an inner housing located in the lower chamber, and a check ball valve assembly located in the plunger and configured to selectively release hydraulic fluid into an inner chamber of the plunger.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Prov. App. No. 63 / 342,519, filed May 16, 2022, which is hereby incorporated by reference as if reproduced in its entirety BACKGROUND

[0002] The present disclosure relates generally to variable valve actuation and, more particularly, to an improved hydraulic lash adjustment capsule.

[0003] Internal combustion engines typically use either a mechanical, electrical, or hydromechanical valve actuation system to operate the engine valves. These systems may include a combination of camshafts, rocker arms, and pushrods driven by the rotation of the engine's crankshaft. In a typical valvetrain assembly used with a compression engine brake, the exhaust valve is actuated by a rocker arm that engages the exhaust valve via a valve bridge. The rocker arm moves in response to a cam on a rotating camshaft, pushing on the valve bridge, which in turn pushes on the exhaust valve to open it. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The following figures serve to illustrate certain aspects of the present disclosure and should not be considered exclusive embodiments. The disclosed subject matter may be significantly modified, altered, combined, and equivalently configured in form and function without departing from the scope of this disclosure. Fig. 1 shows a perspective view of a valvetrain assembly having a rocker arm assembly including an intake rocker arm assembly, an exhaust rocker arm assembly, and an engine brake rocker arm assembly, according to one or more aspects of the present disclosure. Fig. 2 is a second perspective view of the valve train assembly of Fig. 1, with the intake rocker arm and associated intake valves removed for illustration, in accordance with one or more aspects of the present disclosure. Fig. 3 shows a cross-sectional view of an engine brake capsule assembly of the engine brake rocker arm assembly of Fig. 1 according to one or more aspects of the present disclosure. DETAILED DESCRIPTION

[0005] Illustrative embodiments of the present invention are described in detail herein. For clarity, not all features of a specific embodiment are described in this description. It should be understood that in developing such a specific embodiment, numerous implementation-specific decisions may be made to achieve the specific implementation goals, which may vary from one implementation to another. Furthermore, it should be noted that such a development effort may be complex and time-consuming, but is nevertheless a routine effort for those of ordinary skill in the art and having the benefit of the present disclosure.

[0006] Throughout the disclosure, a reference number followed by an alphabetic character refers to a specific instance of an element, and the reference number alone refers to the element generally or as a whole. For example, widget "1a" (not shown in the drawings) refers to an instance of a widget class that may collectively be referred to as widgets "1," each of which may be referred to generically as widget "1." Throughout the figures and the description, like numerals are intended to represent like elements.

[0007] As used herein, the terms "couple" or "couples" are intended to mean either an indirect or a direct connection. Thus, when a first device is coupled to a second device, this connection may be through a direct connection or through an indirect electrical connection or shaft coupling via other devices and connections.

[0008] To facilitate understanding of the present disclosure, examples of specific embodiments are set forth below. The following examples are not intended to limit or define the scope of the disclosure in any way. The embodiments described below with respect to one implementation are not intended to be limiting.

[0009] The present disclosure provides a special rocker arm for engine braking acting on an exhaust valve. With reference to Fig. 1-2, a partial view of a valvetrain assembly constructed in accordance with an example of the present disclosure is shown, generally designated by reference numeral 10. The partial valvetrain assembly 10 may utilize engine braking and is configured for use in a three-cylinder bank portion of a six-cylinder engine. However, it will be appreciated that the present teachings are not so limited. In this regard, the present disclosure may be used in any valvetrain assembly utilizing engine braking or in other suitable valvetrains. The partial valvetrain assembly 10 may be supported within a valvetrain carrier 12 and may include three rocker arms per cylinder.

[0010] Specifically, each cylinder may include an intake valve rocker arm assembly 14, an exhaust valve rocker arm assembly 16, and an engine braking rocker arm assembly 18. The exhaust valve rocker arm assembly 16 and the engine braking rocker arm assembly 18 work together to control the opening of the exhaust valves and are collectively referred to as a dual exhaust valve rocker arm assembly 20, although each is a separate rocker arm acting on a single valve. The intake valve rocker arm assembly 14 is configured to control the movement of the intake valves 22, 24. The exhaust valve rocker arm assembly 16 is configured to control the movement of the exhaust valves in a drive mode. The engine braking rocker arm assembly 18 is configured to act on one of the two exhaust arms in an engine braking mode, as described herein.A rocker arm shaft 26 is received by the valve carrier 12 and assists in the rotation of the exhaust valve rocker arm assembly 16 and the engine brake rocker arm assembly 18.

[0011] With further reference to the Fig. 1-2, the exhaust valve rocker arm assembly 16 may generally include an exhaust rocker arm 28, a valve bridge 30, and a pintle assembly 32. A lever 34 may be pivotally coupled to the valve bridge 30 so that during a braking event, an engine braking rocker arm 36 does not transmit movement to the valve bridge 30. In alternative embodiments, the valve bridge 30 may function without the lever 34. The engine braking rocker arm assembly 18 may connect the engine braking rocker arm 36 to an engagement portion (such as the tappet 102, as shown in Fig. 3). The valve bridge 30 engages first and second exhaust valves 38 and 40 associated with a cylinder of an engine. The engine brake rocker arm 36 may include an engine brake capsule assembly (described further below) configured to switch between a drive mode and an engine brake mode. Generally, the engine brake capsule assembly has a tappet movably disposed within a cylinder. In embodiments, the tappet may have an engagement portion (e.g., an E-foot) engageable with the valve bridge 30. The rocker arm shaft 26 may define an oil supply passage 41, wherein the cylinder of the engine brake capsule assembly may be supplied with pressurized fluid from the oil supply passage 41, thereby extending or retracting the tappet.

[0012] A camshaft 42 includes an exhaust main lift cam lobe 44 and an engine retarding cam lobe 46. The exhaust rocker arm 28 has a first roller 48. The engine retarding rocker arm 36 has a second roller 50. The first roller 48 rotatably engages the exhaust main lift cam lobe 44. As described in more detail herein, the second roller 50 is configured to selectively rotatably engage the engine retarding cam lobe 46. The exhaust rocker arm 28 rotates about the rocker arm shaft 26 based on a lift profile of the exhaust main lift cam lobe 44. The engine retarding rocker arm 36 rotates about the rocker arm shaft 26 based on a lift profile of the engine retarding cam lobe 46.

[0013] Fig. 3 shows a cross-sectional view of an engine brake capsule assembly 100 and the engine brake rocker arm 36 according to one or more aspects of the present disclosure. The present disclosure discusses the use of a combined dual exhaust valve rocker arm assembly 20 (see Fig. 1) or only a special engine brake rocker arm assembly 18 (see Fig. 1-2) with the engine brake capsule assembly 100. The engine brake capsule assembly 100 may be configured to transition between a retracted position and an extended position, wherein the engine brake capsule assembly 100 in the retracted position does not engage a valve bridge (such as the one shown in Fig. 1-2) and wherein the engine brake capsule assembly 100 in the extended position can selectively engage the valve bridge to open the second exhaust valve 40 (see Fig. 2). In one or more embodiments, the exhaust valve rocker arm assembly 16 (see Fig. 1-2) must be deactivated before initiating activation of the engine brake capsule assembly 100 in the engine brake rocker arm 36. The engine brake capsule assembly 100 may have any suitable size, height, shape, and any combination thereof. Furthermore, the engine brake capsule assembly 100 may comprise any suitable materials, e.g., metals, non-metals, polymers, composites, and any combination thereof. As illustrated, the engine brake capsule assembly 100 may be disposed at a valve end of the engine brake rocker arm 36 engageable with the second exhaust valve 40.

[0014] In previous embodiments, the engine brake capsule assembly 100 may require active, mechanical adjustment of the clearance between a tappet 102 of the engine brake capsule assembly 100 and the second exhaust valve 40. The present embodiments of the engine brake capsule assembly 100 may eliminate this problem by providing automatic clearance adjustment via the fluid connection between the engine brake capsule assembly 100 and the rocker arm shaft 26 (see Fig. 1-2).

[0015] The engine brake capsule assembly 100 may include a body 104, the plunger 102, a check ball valve assembly 106, an actuating pin 108, and a locking pin 110. In embodiments, the body 104 may be disposed within a bore at a valve end of the engine brake rocker arm 36. The body 104 may function as a bore / housing within the body of the rocker arm 36. The body 104 may be configured to receive and / or contain the components of the engine brake capsule assembly 100. As illustrated, the body 104 may include a lower chamber 112 and an upper chamber 114. In embodiments, the upper chamber 114 may be disposed above the lower chamber 112. The body 104 may be configured to receive hydraulic fluid supplied from the rocker arm shaft 26, wherein the rocker arm shaft 26 is disposed through a central bore 116 of the engine brake rocker arm 36.In embodiments, the hydraulic fluid may enter both the upper chamber 114 and the lower chamber 112.

[0016] As illustrated, the plunger 102 may be disposed within the body 104 and in at least a portion of the lower chamber 112. The plunger 102 may be configured to translate along the length of the lower chamber 112 and extend partially outward beyond the lower chamber 112. The plunger 102 may be disposed at least partially around an inner housing 118 configured to provide a seat for the check ball valve assembly 106 within the plunger 102. The inner housing 118 may include one or more openings 120 configured to allow fluid communication between the lower chamber 112 and an inner chamber 122 of the plunger 102. For example, an inner chamber 122 may be disposed within the plunger 102 to house the check ball valve assembly 106.

[0017] The check ball valve assembly 106 may be configured to selectively release hydraulic fluid into the inner chamber 122 to cause displacement of the plunger 102 from the retracted position to the extended position. As illustrated, the check ball valve assembly 106 may be configured to abut an inner shoulder 124 provided by a lower end of the inner housing 118. Hydraulic fluid may be introduced into the inner housing 118, flow past the check ball valve assembly 106, and flow into the inner chamber 122. As illustrated, the actuating pin 108 may extend downwardly and press against the ball of the check ball valve assembly 106, thereby disengaging the ball from the inner shoulder 124. This may allow free flow of fluid into and out of the inner chamber 122 when the check ball valve assembly 106 is in the abutted state.During operation, the actuating pin 108 may be actuated to move upward and release the force exerted on the check ball valve assembly 106. As a result, the check ball valve assembly 106 may abut the inner shoulder 124 and prevent fluid communication.

[0018] The engine brake capsule assembly 100 may further include a first spring 126 disposed within the inner chamber 122 and configured to bias the plunger 102 downwardly into the extended position. In embodiments, both the first spring 126 and the introduction of hydraulic fluid into the inner chamber 122 may move the plunger 102 to the extended position.

[0019] The plunger 102 may include a cutout along one side of the plunger 102 that defines an outer shoulder 128. The outer shoulder 128 may be configured to receive the locking pin 110. In embodiments, the locking pin 110 may be disposed within the body 104 and configured to extend into the lower chamber 112 to engage the outer shoulder 128 of the plunger 102. The locking pin 110 may be configured to prevent translation of the plunger 102 and lock the plunger 102 relative to the lower chamber 112. The locking pin 110 may utilize a second spring 130 to bias the locking pin 110 toward the lower chamber 112.

[0020] In embodiments, the engine brake rocker arm 36 may include a first oil passage 132, a second oil passage 134, and a third oil passage 136. Each of the first, second, and third oil passages 132, 134, 136 may fluidly connect the central bore 116 to the engine brake capsule assembly 100. The first oil passage 132 may be configured to provide fluid communication between the upper chamber 114 and the central bore 116. The second oil passage 134 may be configured to provide fluid communication between a space in the lower chamber 112 and the central bore, the space defined by the tappet 102 and the locking pin 110. Both the first and second oil passages 132, 134 may be actuated by a further upstream oil control valve to provide a flow of hydraulic fluid. The oil control valve may, for example, be arranged inside or upstream of the rocker arm shaft 26.The third oil passage 136 may be configured to provide fluid communication between the lower chamber 112 and the central bore 116.

[0021] When hydraulic fluid is introduced into the upper chamber 114 via the first oil passage 132, pressure may be applied to the actuating pin 108, causing the actuating pin 108 to move upward, thereby relieving the force exerted on the check ball valve assembly 106. A third spring 138 may be disposed within the upper chamber 114 and configured to bias the actuating pin 108 downward to release the check ball valve assembly 106. As pressure increases, upward displacement of the actuating pin 108 may compress the third spring 138 and cause the check ball valve assembly 106 to close or abut. Because the check ball valve 106 abuts the inner shoulder 124, any hydraulic fluid within the inner chamber 122 may be trapped therein and prevented from flowing outward.

[0022] When hydraulic fluid is introduced into the space in the lower chamber 112 via the second oil passage 134, pressure may be applied to the locking pin 110, causing the locking pin 110 to translate and retract from the plunger 102, thereby disengaging it from the outer shoulder 128. Removing the locking pin 110 from the plunger 102 may allow the plunger to translate and extend outward along the lower chamber 112.

[0023] In embodiments, hydraulic fluid may flow via the third oil passage 136 into the lower chamber 112 and subsequently into the tappet 102 through one or more openings 120 of the inner housing 118. This flow may be controlled independently from that of the first and second oil passages 132, 134, with an oil control valve controlling the flow. When the check ball valve assembly 106 is released, the hydraulic fluid may freely enter and exit the inner chamber 122. In this state, actuation of the engine brake rocker arm 36 may provide a change in the clearance between the tappet 102 and the second exhaust valve 40 (see FIG. Fig.1-2). For example, when an upward force is applied to the plunger 102 as it engages the second exhaust valve 40, the force is transmitted to the hydraulic fluid in the inner chamber 122. The plunger 102 can retract a certain distance depending on the amount of hydraulic fluid that exits the inner chamber 122 due to the applied force. When the check ball valve assembly 106 is in the applied state, the volume of hydraulic fluid in the inner chamber 122 does not change. In this state, the engine brake rocker arm 36 can provide comparatively stiffer operation because the upward force cannot cause the plunger 102 to displace.

[0024] Therefore, the disclosed systems and methods are well suited to achieving the stated and inherent goals and advantages. The specific embodiments disclosed above are illustrative only, as the teachings of the present disclosure may be modified and implemented in different but equivalent ways, as will be apparent to those skilled in the art having the benefit of the teachings described herein. Furthermore, no limitations on the design or construction details shown herein are intended, except as described in the following claims. It is therefore to be understood that the specific embodiments disclosed above may be altered, combined, or modified, and all such variations are within the scope of the present disclosure.The systems and methods illustratively disclosed herein may be conveniently implemented without any element not specifically disclosed herein and without any optional element disclosed herein. While compositions and methods are described with the terms "comprising," "containing," or "including" various components or steps, the compositions and methods may also "consist essentially of" or "consist of" the various components and steps. All of the numbers and ranges disclosed above may vary by some amount. Whenever a range of numbers with a lower limit and an upper limit is disclosed, each number and included range falling within that range is expressly disclosed.In particular, any range of values ​​disclosed herein (in the form "from about a to about b" or equivalently "from about a to b" or equivalently "from about ab") is to be understood to include any number and range falling within the broader range of values. Furthermore, unless expressly and unambiguously defined otherwise by the patentee, the terms in the claims have their plain, ordinary meaning. Furthermore, the indefinite articles "a" or "an" as used in the claims are defined herein to mean one or more than one element of the element they introduce. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 342,519

[0001]

Claims

[1] Rocker arm assembly comprising: a rocker arm with a valve end; and an engine brake capsule assembly disposed at the valve end, the engine brake capsule assembly being movable between a retracted position and an extended position, the engine brake capsule assembly not engaging a valve bridge in the retracted position, and the engine brake capsule assembly selectively engaging the valve bridge in the extended position to open a first exhaust valve, the engine brake capsule assembly comprising: a body comprising a lower chamber and an upper chamber; a plunger partially disposed within the lower chamber, the plunger including an outer shoulder disposed on one side of the plunger; a locking pin configured to extend into the lower chamber and engage the outer shoulder of the plunger; an actuating pin disposed within the upper chamber and extending downwardly into an inner housing disposed within the lower chamber, the plunger disposed around the inner housing and configured to translate with respect to the inner housing; and a check ball valve assembly disposed within the tappet and configured to selectively release hydraulic fluid into an interior chamber of the tappet, the check ball valve assembly further configured to abut a lower end of the inner housing. [2] The rocker arm assembly of claim 1, wherein the rocker arm further includes a central bore configured to receive a rocker arm shaft, the rocker arm shaft being disposed through the central bore of the rocker arm. [3] Rocker arm assembly according to claim 2, wherein the rocker arm further comprises: a first oil passage configured to provide fluid communication between the upper chamber and the central bore; and a second oil passage configured to provide fluid communication between a space and the central bore, the space being defined by the tappet and the locking pin. [4] The rocker arm assembly of claim 3, further comprising an oil control valve configured to provide a flow of hydraulic fluid through the first oil passage and through the second oil passage. [5] The rocker arm assembly of claim 3, wherein the rocker arm further comprises a third oil passage configured to provide fluid communication between the lower chamber and the central bore. [6] The rocker arm assembly of claim 1, wherein the engine brake capsule assembly further comprises a first spring disposed in the inner chamber and configured to bias the plunger downward in the extended position. [7] The rocker arm assembly of claim 6, wherein the engine brake capsule assembly further comprises a second spring disposed in the upper chamber and configured to bias the actuating pin downward to release the check ball valve assembly. [8] The rocker arm assembly of claim 1, wherein the inner housing includes one or more openings configured to provide fluid communication between the lower chamber and the inner chamber of the tappet. [9] The rocker arm assembly of claim 1, wherein the rocker arm further comprises a cam end opposite the valve end, the cam end comprising a roller configured to engage an engine brake cam lobe of a camshaft. [10] Valve train assembly comprising: a first exhaust valve; a second exhaust valve; and a dual exhaust valve rocker arm assembly configured to selectively open the first engine valve and the second engine valve, the dual exhaust valve rocker arm assembly comprising: a first rocker arm comprising a valve end; and an engine brake capsule assembly disposed at the valve end, the engine brake capsule assembly being movable between a retracted position and an extended position, the engine brake capsule assembly not engaging a valve bridge in the retracted position and selectively engaging the valve bridge in the extended position to open the first exhaust valve, the engine brake capsule assembly comprising: a body comprising a lower chamber and an upper chamber; a plunger partially disposed within the lower chamber, the plunger including an outer shoulder disposed on one side of the plunger; a locking pin configured to extend into the lower chamber and engage the outer shoulder of the plunger; an actuating pin disposed in the upper chamber and extending downwardly into an inner housing disposed in the lower chamber, the plunger disposed around the inner housing and configured to translate with respect to the inner housing; and a check ball valve assembly disposed within the tappet and configured to selectively release hydraulic fluid into an interior chamber of the tappet, the check ball valve assembly further configured to abut a lower end of the inner housing. [11] The valve train assembly of claim 10, wherein the first rocker arm further comprises a central bore configured to receive a rocker arm shaft, the rocker arm shaft being disposed through the central bore of the first rocker arm. [12] The valve train assembly of claim 11, wherein the first rocker arm further comprises: a first oil passage configured to provide fluid communication between the upper chamber and the central bore; and a second oil passage configured to provide fluid communication between a space and the central bore, the space being defined by the tappet and the locking pin. [13] The valve train assembly of claim 12, further comprising an oil control valve configured to provide a flow of hydraulic fluid through the first oil passage and through the second oil passage. [14] The valvetrain assembly of claim 12, wherein the first rocker arm further comprises a third oil passage configured to provide fluid communication between the lower chamber and the central bore. [15] The valve train assembly of claim 10, wherein the engine brake capsule assembly further comprises a first spring disposed in the inner chamber and configured to bias the tappet downward in the extended position. [16] The valve train assembly of claim 15, wherein the engine brake capsule assembly further comprises a second spring disposed in the upper chamber and configured to bias the actuating pin downward to release the check ball valve assembly. [17] The valve train assembly of claim 10, wherein the inner housing includes one or more openings configured to provide fluid communication between the lower chamber and the inner chamber of the tappet. [18] The valve train assembly of claim 10, wherein the first rocker arm further comprises a cam end opposite the valve end, the cam end comprising a roller configured to engage an engine brake cam lobe of a camshaft. [19] The valve train assembly of claim 10, further comprising a second rocker arm configured to engage both the first exhaust valve and the second valve via the valve bridge. [20] The valve train assembly of claim 10, further comprising the valve bridge operatively connected to the first exhaust valve and the second exhaust valve.

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