CDA tappet with hydraulic control feed from outside of engine block

Abstract

In one embodiment, a tappet assembly includes a tappet having a latch mechanism, a slot disposed on an outer wall of the tappet and including an entrance providing access to the latch mechanism, and a pin including a fluid passage. The latch mechanism is switchable between a locked position and an unlocked position. The pin is configured to engage with the slot so as to prevent rotation of the tappet about a tappet axis. The fluid passage is configured to be fluidly coupled to the entrance of the slot.

Description

[0001] Citations of relevant applications

[0002] This disclosure is based on and claims the benefit of U.S. Provisional Application No. 63 / 348,632, filed June 3, 2022, entitled "CDA lifter with hydraulic controlfeed from the engine block", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to a system for controlling cylinder deactivation (CDA), and more specifically to a CDA lifter having hydraulically controlled feed from outside the engine block. Background Technology

[0004] Various tappet designs for valve mechanism systems in internal combustion engines have been produced in the past. Typically, such tappets are connected to the camshaft on one side and the engine cylinder on the other to transmit actuation motion from the camshaft to the downstream valves located in the cylinder. Especially for multi-cylinder engines, independent cylinder control for cylinder deactivation is highly desirable, for example, to better regulate engine and / or fuel efficiency as needed; that is, the ability to disable selected cylinder combinations by deactivating the valves in those cylinders. Typically, tappets configured to achieve this CDA function use hydraulic switching components (e.g., latching mechanisms) that can rapidly switch the system from an active mode (i.e., allowing valve actuation motion provided by the camshaft to be transmitted to the cylinder) to a deactivated mode (e.g., motion generated by the camshaft is absorbed by the hydraulic switching component, thus the corresponding valve is not actuated), or vice versa, as needed during operation. However, this usually requires additional fluid passages extending inside the engine block to feed control pressure to the selected tappets, significantly increasing the overall system complexity. Extensive machining is also required to recast the engine block to accommodate the complex channel design, making the construction process expensive and time-consuming.

[0005] Therefore, there is a need to design a simplified system that allows for hydraulic control of CDA operation without significantly increasing engine complexity. Summary of the Invention

[0006] This disclosure proposes a simplified tappet assembly for controlling CDA operation. Specifically, the tappet assembly according to this disclosure utilizes a pin-groove combination to prevent undesirable rotational movement of the roller tappets, while simultaneously enabling hydraulic control for CDA operation. Furthermore, this disclosure proposes an engine block assembly that houses these configured tappets and is adapted to receive hydraulically controlled feed from an external source.

[0007] By controlling the fluid flow through the anti-rotation groove and pin, the need for an additional fluid circuit inside the engine block can be eliminated. Furthermore, since the pin can be mounted externally to the engine block, a hydraulic feed source can be supplied externally to the pin for controlling CDA switching. In this way, it allows for simple modifications to existing engine conditions to accommodate CDA requirements, thereby reducing construction costs and procedural time.

[0008] An embodiment of the tappet assembly according to this disclosure includes: a tappet having a latching mechanism; a groove disposed on the outer wall of the tappet and including an inlet providing access to the latching mechanism; and a pin including a fluid passage. Specifically, the latching mechanism is switchable between a locked position and an unlocked position. In the same embodiment, the pin is configured to engage with the groove to prevent rotation of the tappet about its axis. Furthermore, the fluid passage is configured to be fluidly connected to the inlet of the groove.

[0009] In one embodiment, the groove is elongated. In another embodiment, the length of the groove is configured to maintain engagement with the pin as the tappet travels vertically. In another embodiment, the groove is configured to receive the end of the pin. In yet another embodiment, the width of the groove is slightly larger than the outer diameter of the end of the pin.

[0010] In a specific embodiment, when the pin engages the groove, a gap is formed between the end of the pin and the bottom surface of the groove to allow fluid communication. In a specific embodiment, the inlet is located at the bottom surface of the groove. In a specific embodiment, when the tappet is in the base circle position, the fluid passage is adjacent to the inlet. In a specific embodiment, the latching mechanism is configured to switch to the unlocked position by means of fluid pressure supplied via the fluid passage through the pin.

[0011] In one embodiment, the tappet assembly is configured to be housed within the engine block. In another embodiment, the pin is configured to be externally mounted into the engine block. In yet another embodiment, the fluid passage is configured to be fluidly connected to a fluid supply device external to the engine block.

[0012] An embodiment of the engine block assembly according to this disclosure includes: an engine block; a tappet assembly housed within the engine block; and a pin mounted externally to the engine block and including a fluid passage. Specifically, the tappet assembly may include a tappet having a latching mechanism. The latching mechanism is switchable between a locked position and an unlocked position. Furthermore, the pin is configured to engage a slot to prevent rotation of the tappet about its axis. The fluid passage is configured to fluidly connect to the inlet of the slot.

[0013] In a specific embodiment, the fluid passage is configured to be fluidly connected to a fluid supply device outside the engine block. In a specific embodiment, the pin includes a head configured to mount against the outer wall of the engine block. In a specific embodiment, the pin includes a body portion configured to extend through the outer wall of the engine block. In a specific embodiment, the pin includes an end portion configured to fit into a groove. In a specific embodiment, the groove is elongated. In a specific embodiment, the length of the groove is configured to remain engaged with the pin as the tappet travels vertically. In a specific embodiment, when the pin engages the groove, a gap is formed between the end of the pin and the bottom surface of the groove to allow fluid communication. Attached Figure Description

[0014] Embodiments according to this disclosure will now be described with reference to the accompanying drawings, in which:

[0015] Figure 1 A tappet assembly according to this disclosure is shown;

[0016] Figure 2 It shows Figure 1 A cross-sectional view of the tappet assembly;

[0017] Figure 3 A roller tappet according to this disclosure is shown;

[0018] Figure 4 and Figure 5 The corresponding isometric and cross-sectional views of the pin according to this disclosure are shown; and

[0019] Figure 6 The tappet assembly is shown in its corresponding base circle position and maximum lift position. Detailed Implementation

[0020] Reference will now be made in detail to the examples shown in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. Directional references such as “up,” “down,” “right,” and “left” are for ease of reference to the drawings and are not intended to limit the scope of this disclosure.

[0021] Figure 1An exemplary tappet assembly 100 according to one embodiment of the present disclosure is shown, which is typically housed within an engine block (not shown). In practice, a pair of tappet assemblies may be provided for each engine cylinder to perform intake and exhaust functions, respectively. However, for the sake of simplicity in this disclosure, only one tappet assembly 100 will be described below, which... Figure 1 The front part is shown.

[0022] In the illustrated embodiment, the tappet assembly 100 includes a roller tappet 110 that travels on a camshaft 114 at its roller bearing 116 and is configured to reciprocate in a controllable manner along the tappet axis 118 when actuated by rotation of the camshaft. As shown, the upper portion of the roller tappet 110 can be coupled to the lower end of a push rod 112, the upper end of which can in turn engage a rocker arm (not shown). With this configuration, the vertical displacement of the roller tappet 110 (i.e., via rotation of the camshaft 114) can be transmitted to the rocker arm via the push rod 112, thereby rotating the rocker arm to activate the associated cylinder as needed.

[0023] In a specific embodiment, the tappet assembly 100 can be configured to provide a so-called CDA function, which systematically disables selected cylinder combinations, for example, for better fuel economy or overall engine efficiency, allowing the system to operate on fewer cylinders when less power output is required. For this purpose, the roller tappets 110 can be provided with various switching components to selectively enable and / or disable motion transmission from the camshaft 114 to the rocker arm. For example, these switching components can mechanically switch the roller tappets 110 between a locked mode for cylinder activation and an unlocked mode for cylinder deactivation. Reference will be made below. Figure 2 Describe the details of the switching components.

[0024] Figure 2 A cross-sectional view of the tappet assembly 100 taken along tappet axis 118 is shown. In a specific embodiment, the roller tappet 110 may include an outer body 212 and an inner body 214 located inside the outer body 212 and configured to travel vertically relative to the outer body 212 as needed. For example, the inner body 214 may include a foldable latching mechanism 216 housed in a chamber 224 and designed to mechanically switch between a locked position and an unlocked position. By way of example and not limitation, the latching mechanism 216 may include two locking pins 220, 222 and a spring 218 connected therebetween. In operation, the inner body 214 may be fixed relative to the outer body 212 in a default locked position, in which a biasing force applied by the spring 218 may push the two locking pins 220, 222 outward to engage with an annular recess 226 of the outer body 212. Figure 2This locking configuration is depicted. When this occurs, the inner body 214 is tightly locked to the outer body 212 by means of the extended latching mechanism 216, thereby enabling motion transmission via the roller tappet 110 to activate the associated engine cylinder. In other words, the system is in lift mode. Conversely, for example, when cylinder deactivation is required, hydraulic pressure can be transmitted to chamber 224 to compress locking pins 220, 222, causing them to retract from the annular recess 226 and disengage. In this case, the inner body 214 is released and freely translates vertically within the outer body 212, such that any actuating motion applied via the camshaft 114 can be absorbed by the vertical displacement between the inner body 214 and the outer body 212. In some embodiments, a lostmotion spring 228 may be arranged inside the roller tappet 110 to suppress relative movement between the inner body 214 and the outer body 212. When switching back to lift mode, the hydraulic supply to chamber 224 can be cut off, and spring 218 can again bias the two locking pins 220, 222 outward to return to the locked position.

[0025] It will be understood that the switching components described herein are merely exemplary and are not intended to limit the scope of this disclosure. While the switching of roller tappets has been illustrated above with reference to specific components, these components are provided for illustrative purposes only and are not necessarily essential. In some embodiments, one or more components may be omitted from or added to the roller tappet. Other suitable configurations of roller tappets will be apparent to those skilled in the art and are not described exhaustively in this disclosure.

[0026] Continue to refer to Figure 1 and Figure 2The roller tappet 110 according to this disclosure also includes a groove 120, which can be configured to receive a pin 122. For example, the pin 122 can act as an anti-rotation pin, engaging with the groove 120 to prevent any rotational movement of the roller tappet 110 about the tappet axis 118. Thus, the roller tappet 110 can maintain proper orientation within the tappet bore (not shown), thereby ensuring alignment of the roller bearing 116 with the camshaft 114 and minimizing undesirable wear. Furthermore, the groove 120 can advantageously include an inlet 230 leading to the interior of the roller tappet 110. For example, the inlet 230 can be located near the annular recess 226 such that when the latching mechanism 216 engages the annular recess 226 in a locked configuration, the inlet 230 provides passage to the latching mechanism 216. Correspondingly, in a specific embodiment, a fluid passage 232 can be arranged in the pin 122. Fluid passage 232 can be configured to be fluidly connected to inlet 230 for feeding fluid into inlet 230. For example, in operation, to control cylinder deactivation, hydraulic pressure can be transmitted, for example, via an external fluid supply source to pin 122, through fluid passage 232 to slot 120, and ultimately to inlet 230. Therefore, the internal latching mechanism 216 can be folded under hydraulic pressure, thereby switching roller tappet 110 to a deactivated mode.

[0027] In a configuration where the tappet assembly 100 is housed in an engine block, pin 122 can be mounted from outside the engine block. For example, a through-hole can be formed in the outer wall of the engine block by drilling, boring, or other suitable methods known to those skilled in the art. Pin 122 can be fitted into the through-hole and further extended inward to engage with roller tappet 110. In a specific embodiment, a fluid supply device, such as a hydraulic valve or other suitable fluid source known to those skilled in the art, can be connected to pin 122 to feed fluid to roller tappet 110. As a non-limiting example, the fluid supply device can be constructed outside the engine block and may optionally include a mounting structure that is positioned above pin 122 and fluidly connected to pin 122. It will be understood, however, that this disclosure is not limited thereto. Other suitable configurations of the fluid supply device are also contemplated. For example, a conduit or manifold can be directed to pin 122 to provide hydraulic feed.

[0028] Conventional systems for controlling cylinder deactivation typically require a separate fluid circuit that routes within the engine block to the roller tappets for hydraulically controlled switching. However, this results in a complex channel design for the engine architecture and necessitates recasting and / or redesigning the engine block, significantly increasing cost and process time. The tappet assembly 100 of this disclosure contrasts with prior art designs because it combines fluid feed and anti-rotation capabilities into a single pin-groove configuration, significantly reducing overall system design complexity and simplifying and cost-effectively machining the process. Furthermore, by supplying hydraulically controlled feed externally to the engine block, the system disclosed herein eliminates the need for engine recasting and allows for simple modifications to existing engine conditions, enabling easy adaptation of the engine block to specific customer requirements.

[0029] Figure 3 A separate view of the roller tappet 110 is shown, specifically illustrating the groove 120. In this embodiment, the groove 120 may be located on the outer wall of the roller tappet 110, for example, on the outer surface of the outer body 212. The groove 120 is adapted to engage with the pin 122. By way of example, and not limitation, the groove 120 may be generally elongated and oriented parallel to the tappet axis. For example, the length of the groove 120 may be configured to accommodate tappet travel such that the groove 120 remains engaged with the pin 122 during vertical reciprocating motion of the roller tappet 110. As another example, the width of the groove 120 may be slightly greater than or substantially equal to the end of the pin 122 (e.g., as shown in the image). Figure 4 and Figure 5 The outer diameter of end 410 shown. This arrangement allows groove 120 to receive pin 122 to prevent the roller tappet 110 from rotating about its axis, while still allowing pin 122 to travel vertically relative to the roller tappet 110. As another example, groove 120 can be designed to have a depth such that when pin 122 is properly inserted, there is a gap between the end of pin 122 and the bottom surface of groove 120. In this way, when fluid is fed to roller tappet 110, the hydraulic connection between roller tappet 110 and pin 122 can be maintained to keep the fluid pressure at a desired level, thereby compressing latching mechanism 216 as needed.

[0030] In a specific embodiment, the groove 120 may include an inlet 230. For example, the inlet 230 may be disposed on the bottom surface of the groove 120 and provide access to the internal structure of the roller tappet 110. In one embodiment, the inlet 230 may be located in a vertical position generally aligned with the latching mechanism 216 in a locking configuration. In this way, fluid can be passed through the inlet 230 into the roller tappet 110 to act on the latching mechanism 216, thereby controlling the switching event.

[0031] Figure 4 and Figure 5 A pin 122 according to this disclosure is shown. As already illustrated, pin 122 may be adapted to engage with a groove 120 of roller tappet 110. In a specific embodiment, pin 122 may be configured to have a through passage 232, which may serve as a fluid channel for supplying fluid to the inlet 230 of roller tappet 110. The through passage 232 may extend horizontally through the entire body of pin 122. In a specific embodiment, pin 122 may include an end portion 410, which may be adapted to be received in the groove 120 of roller tappet 110. For example, end portion 410 may be generally cylindrical and have a reduced diameter compared to other portions of pin 122. When received, end portion 410 may guide pin 122 to move vertically along groove 120 while resisting rotation of roller tappet 110 about tappet axis. In a specific embodiment, pin 122 may also include a head 412. For example, when pin 122 is mounted to the engine block from the outside (e.g., by means of a mounting hole), head 412 can press against the outer wall of the engine block, and the body portion 414 of pin 122 can extend through the outer wall. In some exemplary embodiments, although not shown, to facilitate the installation of pin 122, the outer surface of pin 122 may be threaded, allowing pin 122 to be screwed into the engine block. Additionally or alternatively, other suitable mounting features (e.g., fasteners, clamps, etc.) may be provided to help secure pin 122 in place. In specific embodiments, head 412 may be connected to a fluid supply device. For example, head 412 may be configured to facilitate such fluid connection. In the illustrated embodiment, head 412 may include a cavity 416 adapted to receive supplied fluid and guide it to through passage 232. As further shown, head 412 may take a form similar to a bolt with a hexagonal structure for fitting into a fluid supply device. Although described in this manner, those skilled in the art will understand that pin 122 may be formed differently to perform the desired functions of this disclosure.

[0032] Figure 6The tappet assembly 100 is schematically shown in its corresponding base circle and maximum lift positions. As shown, the tappet assembly 100 is housed within the engine block 610. A pin 122 is inserted through the outer wall of the engine block 610 and extends further inward to engage a groove 120 of a roller tappet 110 located within the engine block 610. Although not shown, a fluid circuit can be coupled from outside the engine block 610 to the pin 122 to provide hydraulic feed to the roller tappet 110, thereby controlling the CDA function as needed. During operation, when the roller tappet 110 is on the base circle (i.e., the lowest position receiving zero lift from the camshaft as shown on the left), the pin 122 can be positioned relative to the roller tappet 110 in a position where the pin 122 is directly aligned with the latching mechanism 216. In some embodiments, it may be desirable to switch in this configuration where fluid can flow through the pin 122 and push the latching mechanism 216 to the unlocked position. When the roller tappet 110 is on the base circle... Figure 6 When in the maximum lift position shown on the right, pin 122 can be located in the lower position in slot 120. If cylinder deactivation is still required, fluid can still be supplied from pin 122 through the gap between the end of pin 122 and the bottom surface of slot 120 to inlet 230 to keep latching mechanism 216 retracted.

[0033] In this document, unless otherwise explicitly indicated or indicated by context, "or" is inclusive rather than exclusive. Therefore, in this document, unless otherwise explicitly indicated or indicated by context, "A or B" means "A, B, or both". Furthermore, unless otherwise explicitly indicated or indicated by context, "and" is both joint and separate. Therefore, in this document, unless otherwise explicitly indicated or indicated by context, "A and B" means "A and B, jointly or separately".

[0034] The scope of this disclosure covers all changes, substitutions, variations, alterations, and modifications to the exemplary embodiments described or illustrated herein, as will be understood by those skilled in the art. The scope of this disclosure is not limited to the exemplary embodiments described or illustrated herein. Furthermore, although this disclosure describes and illustrates corresponding embodiments herein as including specific components, elements, features, functions, operations, or steps, those skilled in the art will understand that any of these embodiments may include any combination or arrangement of any component, element, feature, function, operation, or step described or illustrated anywhere herein. Moreover, in the appended claims, references to means or systems adapted to, arranged to, capable of, configured to, enabled, operable to, or operated to perform a particular function cover any means, whether the means, system, or component, or the particular function, is activated, turned on, or unlocked, provided that the means, system, or component is adapted, arranged, capable of, configured to, enabled, operable, or operated. Furthermore, although this disclosure describes or illustrates specific embodiments to provide particular advantages, the specific embodiments may not provide these advantages, or may provide some or all of these advantages.

Claims

1. A tappet assembly, comprising: The tappet includes a latching mechanism that can switch between a locked position and an unlocked position. A groove, disposed on the outer wall of the tappet, includes an inlet that provides passage to the latching mechanism, and Pins, including fluid channels, The pin is configured to engage with the groove to prevent the tappet from rotating about its axis, and the fluid passage is configured to be fluidly connected to the inlet of the groove. The groove has a length configured to remain engaged with the pin as the tappet travels in a vertical direction; The latching mechanism is configured to switch to the unlocked position by means of fluid pressure supplied via the fluid passage of the pin.

2. The tappet assembly according to claim 1, wherein, The groove is elongated.

3. The tappet assembly according to claim 1, wherein, The slot is configured to receive the end of the pin.

4. The tappet assembly according to claim 3, wherein, The groove has a width slightly larger than the outer diameter of the end of the pin.

5. The tappet assembly according to claim 1, wherein, When the pin engages with the groove, a gap is formed between the end of the pin and the bottom surface of the groove to allow fluid communication.

6. The tappet assembly according to claim 1, wherein, The inlet is located on the bottom surface of the groove.

7. The tappet assembly according to claim 1, wherein, When the tappet is in the base circle position, the fluid channel is adjacent to the inlet.

8. The tappet assembly according to claim 1, wherein, The tappet assembly is configured to be housed inside the engine block.

9. The tappet assembly according to claim 8, wherein, The pin is configured to be installed externally into the engine block.

10. The tappet assembly according to claim 8, wherein, The fluid passage is configured to be fluidly connected to a fluid supply device outside the engine block.

11. An engine cylinder block assembly, comprising: Engine block; A tappet assembly, housed within the engine block, and comprising: The tappet includes a latching mechanism that can switch between a locked position and an unlocked position. A groove, disposed on the outer wall of the tappet, and including an inlet providing passage to the latching mechanism; and A pin, mounted from outside the engine block, and including a fluid passage; The pin is configured to engage with the groove to prevent the tappet from rotating about its axis, and the fluid passage is configured to be fluidly connected to the inlet of the groove. The groove has a length configured to remain engaged with the pin as the tappet travels in a vertical direction; The latching mechanism is configured to switch to the unlocked position by means of fluid pressure supplied via the fluid passage of the pin.

12. The engine cylinder block assembly according to claim 11, wherein, The fluid passage is configured to be fluidly connected to a fluid supply device outside the engine block.

13. The engine block assembly according to claim 11, wherein, The pin includes a head configured to be mounted against the outer wall of the engine block.

14. The engine cylinder block assembly according to claim 11, wherein, The pin includes a body portion configured to extend through the outer wall of the engine block.

15. The engine block assembly according to claim 11, wherein, The pin includes an end configured to be fitted into the slot.

16. The engine cylinder block assembly according to claim 11, wherein, The groove is elongated.

17. The engine cylinder block assembly according to claim 11, wherein, When the pin engages with the groove, a gap is formed between the end of the pin and the bottom surface of the groove to allow fluid communication.

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