Valve actuation system including lost motion and high-lift transfer components in the primary motion load path

Abstract

A valve actuation system includes a valve actuation motion source configured to provide a primary event valve actuation motion to at least one engine valve via a primary motion load path including at least one valve train component. The valve actuation system also includes a lost motion component disposed within the first valve train component in the primary motion load path, the lost motion component being controllable to operate in either a motion transmitting state or a motion absorbing state. The valve actuation system also includes a high-lift transmitting component disposed in the primary motion load path, wherein the high-lift transmitting component is configured to allow the primary motion load path to transmit at least a high-lift portion of the primary event valve actuation motion when the lost motion component is in the motion absorbing state.

Description

Technical Field

[0001] This disclosure relates in general to valve actuation systems in internal combustion engines, and more particularly to valve actuation systems that include aerodynamic and high-lift transmission components in the main motion load path. Background Technology

[0002] Valve actuation systems for internal combustion engines are known in the art. During positive power operation of an internal combustion engine, a valve actuation system is used to combine fuel combustion with providing valve actuation motion from a valve actuation motion source to one or more engine valves (intake or exhaust valves) via a motion load path or valve mechanism, so that the engine output can be used, for example, to operate the vehicle. As used herein, a motion source is any component that indicates the motion to be applied to the engine valve, such as a cam, while a motion load path or valve mechanism includes one or more components deployed between the motion source and the engine valve and used to transmit the motion provided by the motion source to the engine valve, such as tappets, rocker arms, pushrods, valve crossarms, automatic clearance adjusters, etc. Furthermore, as used herein, the descriptive terms “primary” or “main” refer to the characteristics of the engine valve motion of the so-called primary event, i.e., the valve motion used during positive power generation and the motion load path used to transmit such valve motion.

[0003] Valve actuation systems can also operate by completely stopping the operation of a given engine cylinder by eliminating any engine valve actuation (and stopping fuel supply), commonly referred to as cylinder deactivation (CDA). Such CDA systems typically operate independently on the intake and exhaust valves, allowing each valve to be deactivated independently. The benefits of CDA include reduced fuel consumption and increased exhaust temperature, which provides improved aftertreatment emission control. In some systems, CDA is achieved by using folding or aerodynamic components deployed in a motion load path capable of switching between a rigid / extended (or motion-transmitting) state and a folded / retracted (or motion-absorbing) state. In the former state, valve actuation motion from the valve actuation motion source is transmitted to the engine valve via the aerodynamic component. In the latter state, valve actuation motion is dissipated by the aerodynamic component, such that no valve actuation motion is applied to the engine valve, i.e., the engine valve remains closed. Such aerodynamic components are known in the art and typically include mechanical devices capable of locking / unlocking or hydraulic devices capable of capturing / releasing trapped volumes of hydraulic fluid.

[0004] In systems where CDA is achieved via aerodynamic components, numerous factors can lead to failure modes of these components. These failure modes include mechanical component failure, component fatigue failure, system control errors leading to unintended activation, debris preventing the folding element from relocking, vibration, incorrect clearance settings, excessive heat growth, and excessive wear of critical components such as valve seats.

[0005] Furthermore, there are specific operating conditions, such as those for four-stroke engines, where engine overload and potentially catastrophic engine damage can occur during the main event shutdown. Specifically, if the main motion load path for the exhaust valves is shut down (whether intentionally or unintentionally), but the main motion load path for the corresponding intake valves is not shut down, the intake main motion load path can see significant load on the intake main event because the pressure in the cylinders is not exhausted. Even under driving conditions, this load may exceed the design of the valve mechanism and worsen with fuel injection. This failure mode can also expose the intake system to excessively high pressures and temperatures. For example, if there is an unexhausted combustion event during the power stroke due to a CDA mechanism failure, the combustion pressure and gases will travel into the intake system during subsequent intake events, leading to damage to the intake system. Even worse, such very high intake load events can lead to excessive loads on the entire engine, including the gear train and crankshaft.

[0006] To mitigate the possibility of unintentional or accidental CDA (Discharge Damage) operation, it is feasible to design the engine system to be extremely robust, preventing significant damage to the engine. This is easier to achieve in smaller displacement engines, where the loads applied to the engine in fault mode are within the design limits of normal materials. However, such a design is difficult to implement in heavy-duty engines, where cylinder pressures are typically much higher.

[0007] Furthermore, in automotive applications, it is known in the art to measure certain engine parameters to detect whether a cylinder deactivation element has been successfully locked or unlocked. In the event of a detected problem (e.g., accidental locking or unlocking), the engine controller will activate a protection mode (sometimes called "limp home" mode), in which the cylinder is completely deactivated (i.e., both intake and exhaust valve actuation movements are interrupted) to prevent any further engine damage.

[0008] In the field of heavy-duty engines, the "HPD" system developed by Jacobs Vehicle Systems, Inc. (as described, for example, in U.S. Patent No. 8,936,006) features a fail-safe lift provided by a motion source, ensuring reduced cylinder pressure to protect valve train loads in the event of a CDA component failure. This fail-safe lift is designed to originate from a separate valve train component, specifically the engine brake rocker arm. Additionally, U.S. Patent No. 6,854,433 describes an auxiliary motion load path that allows at least some valve actuation even in the event of an aerodynamic system failure in the main motion load path. This system... Figure 1The diagram schematically illustrates an internal combustion engine 100 having a valve actuation system 102, which includes a main motion load path 104 and a main valve actuation motion source 106 providing main event valve actuation motion to a rocker arm 108. The main event valve actuation motion is then transmitted via an aerodynamic system 110 and a valve crossarm 112 to one or more engine valves 114. As described above, the aerodynamic system 110, including an independent hydraulic actuation system, can operate in either a motion transmission or motion absorption state. Further as shown in the '433 patent, the rocker arm 108 includes an "auxiliary system" 122 in the form of a protrusion or bulge exiting the rocker arm 108 and aligned with one of the engine valves of the valve crossarm 112 and / or the engine valve 114. During operation when the aerodynamic system is in a motion-absorbing state (whether intentional or due to a malfunction), the auxiliary system 122 is configured such that at least some of the primary event valve actuation movements transmitted by the rocker arm 108 are also applied to the valve crossarm 112 / valve 114, thereby ensuring the opening of valve 114 regardless of the inoperability / malfunction of the aerodynamic system 110. In this way, the auxiliary system 122 generates an auxiliary motion load path 120 that bypasses the primary motion load path 104.

[0009] While the solutions described above have proven beneficial, further development in this area would be welcome. Summary of the Invention

[0010] This disclosure relates to a valve actuation system including a valve actuation motion source configured to provide a primary event valve actuation motion to at least one engine valve via a primary motion load path including at least one valve mechanism component. The valve actuation system also includes a vacant member disposed within a first valve mechanism component in the primary motion load path, the vacant member being controllable to operate in a motion transmission state where the vacant member transmits the primary event valve actuation motion, or in a motion absorption state where the vacant member does not transmit at least a portion of the primary event valve actuation motion. Furthermore, the valve actuation system includes a high-lift transmission member disposed in the primary motion load path, wherein the high-lift transmission member is configured to allow the primary motion load path to transmit at least a high-lift portion of the primary event valve actuation motion when the vacant member is in a motion absorption state. In various embodiments, the first valve mechanism component may include a valve crossarm, rocker arm, or pushrod.

[0011] In one embodiment, a high-lift transmission component is integrated into the pneumatic component, and in certain embodiments, it may be implemented as a stroke-limiting feature within the pneumatic component. In these embodiments, the pneumatic component may include a mechanical locking subsystem or a hydraulic locking subsystem. Alternatively, the high-lift transmission component integrated into the pneumatic component may be implemented as an auxiliary locking subsystem.

[0012] In other embodiments, the high-lift transmission component is integrated into at least one valve mechanism component (such as a valve crossarm, rocker arm, or pushrod) in the main motion load path, and in certain embodiments, it may be implemented as a stroke-limiting feature in at least one valve mechanism component. In these embodiments, the stroke-limiting feature may include at least one contact surface disposed on at least one valve mechanism component. Alternatively, the at least one contact surface may be implemented as a retractable piston, such as a hydraulically actuated piston. Attached Figure Description

[0013] The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of a particular embodiment, in conjunction with the accompanying drawings, wherein:

[0014] Figure 1 This is a schematic diagram of a valve actuation system based on existing technology;

[0015] Figure 2 and Figure 3 These are schematic diagrams of various embodiments of the valve actuation system according to this disclosure;

[0016] Figure 4 It is a graph showing the main exhaust and intake events according to this disclosure, as well as the high-lift portion of the exhaust event transmitted by the high-lift transmission component;

[0017] Figures 5 to 10 It shows the basis Figure 2 Cross-sectional views of various specific embodiments of the high-lift transmission component in the implementation scheme; and

[0018] Figures 11 to 15 It shows that according to Figure 3 Various specific implementations of the high-lift transmission components of the implementation plan. Detailed Implementation

[0019] As used herein, any reference to direction (e.g., top, bottom, up, down, left, right, etc.) is defined relative to the orientation shown in the corresponding figures.

[0020] See now Figure 2The document describes an internal combustion engine 200 including a valve actuation system 202 according to the present disclosure. The valve actuation system 202 includes a primary motion source 204 that provides primary event valve actuation motion to a first valve mechanism component 206. In this embodiment, the first valve mechanism component 206 includes an aerodynamic component 208 disposed therein, the aerodynamic component 208 further including a high-lift transmission component 210 disposed therein. As described above, the aerodynamic component 208 is generally operable in a motion transmission state or a motion absorption state. Subsequently, and as further described below, the aerodynamic component 206, alone or through the operation of the high-lift transmission component 210, provides at least a portion of the primary event valve actuation motion to a second valve mechanism component 212, which in turn provides the received valve actuation motion to one or more engine valves 214. As those skilled in the art will understand, the valve actuation system described herein can be applied to exhaust engine valves or intake engine valves, or both. The valve mechanism components 206 and 212 depicted can be any of a variety of well-known valve mechanisms, such as valve crossarm, rocker arm (end pivot or center pivot type), pushrod, tappet, etc.

[0021] In short, Figure 2 The first and second valve mechanism components shown constitute the main motion load path, which necessitates that the aerodynamic component 208 and the high-lift transmission component 210 operate entirely within the main motion load path when integrated into the first valve mechanism component 206. Furthermore, although... Figure 2 The main motion load path depicted constitutes two valve mechanism components, but those skilled in the art will further understand that more or fewer valve mechanism components can be used for this purpose. Furthermore, although the aerodynamic component 208 and the high-lift transmission component 210 are depicted as being integrated into the first valve mechanism component 206 closest to the valve actuation motion source, this is not a necessary condition, and the aerodynamic component 208 and its corresponding high-lift transmission component 210 can be equivalently arranged in some other valve mechanism component such as the second valve mechanism component 212; this is a matter of design choice.

[0022] As used herein, the descriptive term "high lift" generally refers to various aspects of this disclosure relating to providing any portion of the primary event valve actuation motion that is greater than a lower lift threshold, which is greater than zero and less than the maximum lift typically provided by the primary event valve actuation motion. For example, for a primary event valve actuation motion with a maximum valve lift of 15 mm, the lower lift threshold may be selected to be arbitrarily close to, but not equal to, zero, such that the high lift portion will encompass almost all of the primary event valve actuation motion. On the other hand, the lower lift threshold may be selected to be arbitrarily close to, but not equal to, the 15 mm maximum lift value, such that the high lift portion will encompass almost all of the primary event valve actuation motion except for the valve lift value closest to the 15 mm maximum value. As this example clearly demonstrates, the lower lift threshold defining the high lift portion can be set to be close to any limit of the primary event valve actuation motion. However, in practice, it is generally acceptable to set the lower lift threshold to a value that provides a sufficient amount of valve lift (e.g., 2 mm or more) to ensure at least a certain level of cylinder decompression required to avoid potential damage to the engine, especially in the case of exhaust master event valve actuation, but preferably not high enough to significantly affect the air springs generated in the CDA and known to reduce friction and pumping losses. In this way, the high lift portion operates as a fail-safe lift in the event of unintended or other erroneous CDA operation to prevent engine damage.

[0023] Figure 4 A specific example of the high-lift portion of the main event valve actuation motion is depicted, illustrating a well-known example of the valve actuation motion of the main exhaust 402 and main intake 404. In this example, a maximum lift of approximately 12 mm is provided, and a high-lift portion 406 of approximately 2 mm is provided using any of the various valve actuation motion systems disclosed herein. That is, a lower lift threshold is set to 10 mm, such that any portion 408 of the exhaust main event 402 is consumed by the aerodynamic component 208.

[0024] See you again Figure 2The high-lift transmission member 210, incorporated into the aerodynamic component 208, is configured to ensure the transmission of at least the high-lift portion of the primary event valve actuation motion by the aerodynamic component 208 when operating in the motion absorption state. In various embodiments described below, the high-lift transmission member 210 may be implemented as a stroke limiting feature or auxiliary locking feature incorporated into the aerodynamic component 208. When operating in the motion transmission state, the aerodynamic component 208 is used to transmit the primary event valve actuation motion received by the first valve mechanism component 206 to the second valve mechanism component 212, as indicated by the solid arrow between the aerodynamic component 206 and the second valve mechanism component 212. On the other hand, when operating in motion absorption state (whether through such intentional control or due to the occurrence of a fault mode), the function of the high-lift transmission component 210 still allows the aerodynamic component 206 to transmit at least a portion of the main event valve actuation motion received by the first valve mechanism component 206 to the second valve mechanism component 212, as indicated by the dashed arrow between the high-lift transmission component 206 and the second valve mechanism component 212.

[0025] See now Figure 3 It depicts an internal combustion engine 300 including a valve actuation system 302 according to the present disclosure. Specifically, the valve actuation system 302 is substantially similar to... Figure 2 The system 202 depicted, apart from the structures of the aerodynamic component 304 and the high-lift transmission component 306 mentioned below, specifically, in this embodiment, the aerodynamic component 304 is again integrated into the first valve mechanism component 206; however, the high-lift transmission component 306 is not... Figure 2 Instead of being integrated into the aerodynamic component 304 as in the previous configuration, it is also integrated into the first valve mechanism component 206. In other words, the high-lift transmission component 306 is actually connected in parallel with the aerodynamic component 304, which is consistent with... Figure 2 The depicted inline or tandem arrangements are the opposite. Although shown as a feature in the first valve mechanism component 206, it should be understood that the high-lift transfer component 306 can be implemented in different valve mechanism components such as the second valve mechanism component 212. Furthermore, it should be understood that the high-lift transfer component 306 can be implemented across more than one valve mechanism component. In the various specific embodiments described below, the high-lift transfer component 306 can be implemented as a stroke-limiting feature, for example, in the form of a contact surface deployed on at least one valve mechanism component. Moreover, such a contact surface can be implemented as a retractable piston.

[0026] Figures 5 to 10 It shows that according to Figure 2 Various examples of specific implementations of the high-lift transmission component in the implementation scheme. Figure 5A valve lifter 500 of the type described in U.S. Patent No. 9,790,824 is shown. Specifically, the valve lifter 500 includes a pneumatic member 505 disposed in a central bore 512 formed in a body 510 of the valve lifter 500. The pneumatic member 505 includes an outer plunger 520 slidably disposed in the central bore 512. A locking element in the form of a wedge 580 is provided, configured to engage an annular recess 572 formed in the surface defining the bore 512. In the absence of hydraulic control applied to the inner plunger 560 (in this case, via a rocker arm, not shown), an inner piston spring 544 biases the inner plunger 560 into place such that the wedge 580 extends out of an opening formed in the outer plunger 520, thereby engaging the recess 572 and effectively locking the outer plunger 520 in place relative to the valve lifter body 510. In this locked or motion-transmitting state, any valve actuation motion applied to the valve crossarm 500 via the outer plunger 520 is transmitted to the valve crossarm body 510 and ultimately to the engine valve (not shown). However, supplying sufficiently pressurized hydraulic fluid to the top of the inner plunger 560 via the hydraulic passage 590 causes the inner plunger 160 to slide downward, thereby allowing the wedge 580 to retract and disengage from the outer recess 572. This effectively unlocks the outer plunger 520 relative to the valve crossarm body 510 and allows the outer plunger 520 to slide freely within its bore 512, thus experiencing an upward bias provided by the outer plunger spring 546. In this unlocked or motion-absorbing state, any valve actuation motion applied to the outer plunger 520 will cause the outer plunger 520 to reciprocate within its bore 112.

[0027] However, in this embodiment, the high-lift transfer component is provided in the form of a stroke limiter having a stroke length 591 (defined by the downward-facing surface 593 of the outer plunger 520 and the upward-facing surface 595 defined by the bottom of the bore 512), which is designed to be equal to the lower lift limit described above. That is, the stroke length 591 of the outer plunger 520 is selected such that a valve lift greater than the lower lift limit will cause the outer plunger 520 to descend to its lowest point in the bore 512, thereby providing a firm contact between the outer plunger 520 and the valve crossarm body 510, and causing such valve lift to be transferred to the engine valves via the valve crossarm body 520. In this way, the aerodynamic component 505 can provide fail-safe lift as long as it operates in the motion-absorbing state.

[0028] Figure 6 A central pivot (or type III) rocker arm 600 of the type described in U.S. Patent Application Publication No. 2020 / 0182097 is shown. As shown, the rocker arm 600 includes two half-rocker arms 604, 606 having a prying member 605, which is substantially similar to Figure 5The aerodynamic component 505 shown is disposed within a bore 601 formed in a housing 610, which in turn is disposed in a first rocker arm 604. The aerodynamic component 605 makes contact with a contact surface 607 formed on a second half-rocker arm 606. In this embodiment, an outer plunger 612 is slidably disposed with the bore 601, and the outer plunger 612 also has a bore 613 in which an inner plunger 614 is slidably disposed. In the illustrated embodiment, a locking spring 620 biases the inner plunger 614 into the outer plunger bore 613. As long as the biasing force provided by the locking spring 620 is not countered, the inner plunger 614 will be biased into the outer plunger bore 413, thereby causing the wedge 616 to extend through an opening formed in the sidewall of the outer plunger 612 and into an outer recess 618 formed in the inner wall of the housing 610. When the locking element 616 extends and aligns with the outer recess 618, it mechanically prevents the outer plunger 612 from sliding within the housing bore 601. That is, the outer plunger is locked relative to the housing 610, such that any valve actuation motion applied to the first rocker arm 604 is transmitted via the pneumatic member 605 to the contact surface 607 and the second half-rocker arm 206; that is, the pneumatic member 605 operates in motion transmission mode. Conversely, when hydraulic fluid pressure is applied to the outer plunger bore 613, it resists the bias provided by the locking spring 620 and further causes the inner plunger 614 to slide out of the outer plunger bore 613. In doing so, the reduced diameter portion of the inner plunger 614 aligns with the wedge 616, thereby allowing the wedge 616 to retract and disengage from the outer recess 618. In this state, the outer plunger 612 is allowed to slide further into the housing bore 411, i.e., it is unlocked relative to the housing 610, such that any valve actuation motion applied to the first rocker arm 604 is absorbed by the actuation component 605 and not transmitted to the contact surface 607 and the second rocker arm 206, i.e., the actuation component 605 operates in the motion absorption state.

[0029] However, also in this embodiment, the high-lift transmission component is provided in the form of a stroke limiter having a stroke length 691 (defined by the left-facing surface 693 of the outer plunger 612 and the right-facing surface 695 defined by the bottom of the bore 601), which is designed to be equal to the lower lift limit described above. That is, the stroke length 691 of the outer plunger 612 is selected such that a valve lift greater than the lower lift limit will cause the outer plunger 612 to descend to its lowest point in the bore 601, thereby providing a firm contact between the outer plunger 612 and the first half-rocker arm 604, and causing such valve lift to be transmitted to the engine valve by the first half-rocker arm 604, the pneumatic component 605, and the second half-rocker arm 606. In this way, the pneumatic component 605 can provide fail-safe lift as long as it operates in a motion-absorbing state.

[0030] Figure 7An end-pivot (or type II) rocker arm 700 of the type described in U.S. Patent Application Publication No. 2020 / 0291826 is shown. As shown, the rocker arm 700 includes a lever arm 704 rotatably mounted (at its first end 706) to a rocker arm body 702. The lever arm 704 includes a curved end face 716 opposite its first end 706. A prying member 705 includes a latch 712 slidably disposed in a hole 722 defined in a latch protrusion 720 of the rocker arm body 702. The latch 712 includes a lever engagement surface 714 configured to engage the curved end face 716 of the lever arm 704. The position of the latch 712 within the hole 722 can be controlled by operation of an actuating piston 710 of a different diameter such that when the latch 712 is controlled by the actuating piston 710 to its rightmost position, the lever engagement surface 714 will contact the curved end face 716 at its relatively low point. This shifts to a relatively raised position of lever arm 704, such that the valve actuation motion received at the top of roller 708 is transmitted by lever arm 704 to rocker arm body 702 and then to engine valve (not shown). Operated in this manner, pneumatic component 705 is in a motion-transmitting state. Conversely, actuating piston 710 can be operated such that the position of latch 712 within bore 722 is controlled to its leftmost position, causing lever engagement surface 714 to contact curved end face 716 at its relatively high point. This shifts to a relatively lowered position of lever arm 704, such that the valve actuation motion cannot reach roller 708 and is therefore not transmitted by lever arm 704 to rocker arm body 702 and then to engine valve (not shown). Operated in this manner, pneumatic component 705 is in a motion-absorbing state.

[0031] In this embodiment, the high-lift transmission component is provided in the form of a stroke limiter having a stroke length 791 (defined by the downward-facing surface of the lever arm stroke limiter 730 and the upward-facing surface defined by the top surface of the latch protrusion 720), which is designed to be equal to the lower lift limit described above. That is, the stroke length 791 of the lever arm 704 is selected such that a valve lift exceeding the lower lift limit will cause the downward-facing surface of the lever arm stroke limiter 730 to contact the upward-facing surface of the latch protrusion 720, thereby providing a firm contact between the lever arm 704 and the rocker arm body 702, and causing such valve lift to be transmitted from the rocker arm body 702 to the engine valve. In this way, the aerodynamic component 705 can provide fail-safe lift as long as it operates in a motion-absorbing state.

[0032] Figure 8A push tube 800 of the type described in U.S. Patent Application No. 17 / 247,481, assigned to the same assignee as this application, is shown. As shown, the push tube 800 includes a push tube body 802 having a pneumatic member 805, which is substantially similar to Figure 5 The pneumatic component 805 shown is mounted on the push tube body. The pneumatic component 805 includes an outer plunger 820, an inner plunger 860, and a wedge 880, which are designed to interact with… Figure 5 The components with the same names shown operate in the same manner, wherein the outer plunger 820 is slidably disposed within a bore in the housing 804, which is rigidly connected to the push tube body 802. Therefore, when the wedge 880 is controlled to lock the outer plunger 820 relative to the housing 804, the valve actuation motion received via the push tube body 802 is transmitted to the engine valve (not shown) by the actuation component 805. In this manner, the actuation component 805 is in a motion transmission state. Conversely, when the wedge 880 is controlled to unlock the outer plunger 820 relative to the housing 804, the valve actuation motion received via the push tube body 802 is not transmitted to the engine valve by the actuation component 805. In this manner, the actuation component 805 is in a motion absorption state.

[0033] In this embodiment, the high-lift transmission component is provided in the form of a stroke limiter having a stroke length 891 (defined by the downward-facing surface 893 of the outer plunger 820 and the upward-facing surface 895 defined by the bottom of the housing 804), which is designed to be equal to the lower lift limit described above. That is, the stroke length 891 of the outer plunger 820 is selected such that a valve lift greater than the lower lift limit will cause the downward-facing surface 893 to contact the upward-facing surface 895, thereby providing a firm contact between the outer plunger 820 and the housing 804, and causing such valve lift to be transmitted to the engine valves by the aerodynamic component 805. In this way, the aerodynamic component 805 can provide fail-safe lift as long as it operates in a motion-absorbing state.

[0034] Figure 9 and Figure 10 It shows the relationship with Figure 5 The valve lift 500 shown is substantially the same as the valve lift 900. However, in this embodiment, the high-lift transmission component is not implemented as a stroke-limiting feature, but is instead provided by an auxiliary locking subsystem 930. In this embodiment, the auxiliary locking subsystem 930 is provided by a combination of an auxiliary locking piston 932 disposed in an auxiliary locking hole 934 and a locking groove 936 formed in an annular band on the outer surface of the outer plunger 920. Figure 9In this configuration, the inner plunger 960 of the pneumatic component 905 is positioned such that the wedge 980 engages the annular outer groove 972 and locks the outer plunger 920 to the valve crossarm body 910. Operated in this manner, the pneumatic component 905 is in a motion-transmission state, as during positive power generation. During the motion-transmission state of the pneumatic component 905, the auxiliary locking subsystem 930 remains in an unlocked state due to a lack of alignment between the auxiliary locking piston 932 and the locking groove 936; that is, the auxiliary locking subsystem 930 does not prevent any movement of the outer plunger 920 during the motion-transmission state. However, if the wedge 980 fails during the motion-transmission state of the pneumatic component 905, translation of the outer plunger 920 relative to the valve crossarm body 910 is permitted. In this case, the auxiliary locking subsystem 930 performs a fail-safe function when subsequent downward translation of the outer plunger 920 (i.e., after the wedge 980 fails) allows the auxiliary locking piston 932 to align and engage with the locking groove 936. In this configuration, the engagement of the auxiliary locking piston 932 with the locking channel 936 prevents further downward translation of the outer plunger 920, thereby effectively locking it to the valve stem body 910. A fail-safe function is achieved by selectively positioning the locking channel 936 along the longitudinal length of the outer plunger 920, which reflects the lower lift limit.

[0035] When hydraulic fluid is supplied to hydraulic channel 990 to control aerodynamic component 905 to operate in motion absorption state (thus allowing CDA), such as Figure 9 As shown, the presence of a radial channel 940, which is in fluid communication with the proximal end of the hydraulic passage 990 and the locking hole 934, allows pressurized hydraulic fluid to impinge on the auxiliary locking piston 932, thereby causing the auxiliary locking piston to translate to the left and preventing it from engaging with the locking groove 936. Furthermore, see also... Figure 10 The annular outer groove 972 is also in fluid communication with the locking hole 934, such that when the outer plunger 920 has been translated downwards sufficiently to align the auxiliary locking piston 932 with the locking groove 936, the radial passage 940 is also aligned with the annular outer groove 972, thereby continuing to allow pressurized hydraulic fluid to impinge on the surface of the auxiliary locking piston 932 and preventing its locking engagement. Figure 10 (Not shown in the image). In this way, the aerodynamic component 905 is allowed to operate unimpeded in the motion-absorbing state (i.e., not unintentionally), thus also allowing the completion of CDA operations. In the event of an unexpected loss of hydraulic pressure, the auxiliary locking piston 932 and the locking channel 936 will be allowed to engage with each other again, as described above, and provide a fail-safe function.

[0036] Figures 11 to 15 It shows that according to Figure 3 Various examples of specific implementations of the high-lift transmission component in the implementation scheme. Figure 11and Figure 12 A valve actuation system 1100 is shown, including a rocker arm 1102 that receives valve actuation motion from a push tube 1104. Figure 8 Similar to the implementation scheme, the push tube 1104 includes an aerodynamic component 1105. However, with Figure 8 In a different implementation, the aerodynamic component 1105 does not include a stroke-limiting feature that operates as a high-lift transmission component. In this implementation, the high-lift transmission component is provided by a stroke-limiting feature integrated into two valve mechanism components, namely the rocker arm 1102 and the push tube 1104. In this specific implementation, the stroke-limiting feature is provided by a combination of the rocker arm extension 1110 and the push tube guard 1112 surrounding the aerodynamic component 1105, and the stroke length is defined by the interval between the upper surfaces of the rocker arm extension 1110 and the push tube guard 1112. Figure 11 As best shown, the rocker arm extension 1110 includes a C-ring attached to the rocker arm 1102 and configured such that the arm 1111 of the C-ring is aligned with the guard 1112, which is attached to the push tube body 1114 of the push tube 1104. With these arrangements, when the aerodynamic component 1105 operates in motion-absorbing mode, the stroke length defined by the gap between the upper surfaces of the rocker arm extension 1110 and the guard 1112 is designed to be equal to the lower lift limit described above. That is, the stroke length is selected such that a valve lift greater than the lower lift limit will cause the guard to establish a firm contact with the rocker arm extension 1110, thereby causing such valve lift to be transmitted to the rocker arm 1102 and continuing to be transmitted to the engine valves (not shown). In this way, as long as the aerodynamic component 1105 operates in the motion absorption state, the valve mechanism components in the main motion load path (i.e., rocker arm 1102 and push tube 1104) can provide fail-safe lift.

[0037] Figure 13 It shows Figure 3 Two other specific embodiments of the implementation scheme. In this case, the main motion load path includes rocker arm 1302 and valve crossarm 1304. In this case, the valve crossarm is essentially... Figure 5Similar to the valve crossarm in the previous embodiment, but again differing in that the high-lift transfer mechanism is not implemented by a stroke-limiting feature integrated into the aerodynamic component 505. In a first embodiment of these embodiments, the high-lift transfer mechanism is provided by stroke-limiting features integrated into both valve mechanism components (i.e., rocker arm 1302 and valve crossarm 1304). Specifically, the stroke-limiting feature is provided by a combination of a rocker arm guard 1306 deployed on the nose of the rocker arm 1302 and an upper contact surface 1308 of the valve crossarm 1304, such that the stroke length is defined by the gap between the rocker arm guard 1306 and the upper contact surface 1308. With these arrangements, when the aerodynamic component in the valve crossarm 1304 operates in a motion-absorbing state, the stroke length defined by the gap between the rocker arm guard 1306 and the upper contact surface 1308 is designed to be equal to the aforementioned lower lift limit. That is, the stroke length is selected such that a valve lift greater than the lower lift limit will cause the rocker arm guard 1306 to establish firm contact with the upper contact surface 1308, thereby causing such valve lift to be transmitted from the rocker arm 1302 to the valve crossarm 1304 and continue to the engine valves. In this way, as long as the aerodynamic components in the valve crossarm operate in a motion-absorbing state, the valve mechanism components in the main motion load path (i.e., the rocker arm 1302 and the valve crossarm 1304) can provide fail-safe lift.

[0038] In a second embodiment of these implementations, the high-lift transmission component is again provided by an alternative stroke-limiting feature integrated into both valve mechanism components (i.e., rocker arm 1302 and valve crossarm 1304). (In practice, it is not necessary to achieve this simultaneously.) Figure 13 The two travel-limiting features shown; implementing one or the other travel-limiting feature would be sufficient. For ease of explanation, Figure 13Two stroke limiting features are shown. Specifically, the stroke limiting features are provided by a combination of a laterally extending rocker arm extension 1310 disposed in the valve-side portion of the rocker arm 1302 and a laterally extending valve crossarm contact surface 1312 disposed in the valve crossarm 1304 and aligned with the rocker arm extension 1310, such that the stroke length is defined by the gap between the rocker arm extension 1306 and the valve crossarm extension. With these arrangements, when the aerodynamic components in the valve crossarm 1304 operate in a motion-absorbing state, the stroke length defined by the gap between the rocker arm extension 1310 and the valve crossarm extension 1312 is designed to be equal to the aforementioned lower lift limit. That is, the stroke length is selected such that a valve lift greater than the lower lift limit will cause the rocker arm extension 1310 to establish firm contact with the valve crossarm extension 1312, thereby causing such valve lift to be transmitted from the rocker arm 1302 to the valve crossarm 1304 and continue to the engine valves. In this way, similarly, as long as the aerodynamic components in the valve crossarm operate in the motion-absorbing state, the valve mechanism components in the main motion load path (i.e., the rocker arm 1302 and the valve crossarm 1304) can provide fail-safe lift.

[0039] See now Figure 14 and Figure 15 It shows Figure 13 An alternative embodiment of the second embodiment shown is a laterally extending rocker arm extension. In this embodiment, the laterally extending rocker arm extension 1310 is replaced by a hydraulically actuated retractable piston 1406, and the function provided by the valve crossarm extension 1312 is provided by the upper surface 1408 of the valve crossarm 1404. Figure 15 As best shown, piston 1406 is slidably disposed in piston bore 1502 formed in rocker arm 1402. A biasing spring 1504 is provided to bias piston 1406 out of piston bore 1502 such that piston 1406 is aligned with upper surface 1408 of valve crossarm 1404. In this position, piston 1406 and upper surface 1408 are aligned with... Figure 13 The rocker arm extension 1310 and valve crossarm extension 1312 operate in essentially the same manner. However, unlike the rocker arm extension 1310 and valve crossarm extension 1312, the piston 1406 can be retracted by supplying hydraulic fluid to the piston 1406 via a hydraulic passage 1506 formed in the rocker arm 1402. The pressurization of the hydraulic fluid on the piston 1406 is sufficient to overcome the bias of the bias spring 1504, causing the piston 1406 to retract into the bore 1502, thereby eliminating any interaction between the piston 1406 and the upper surface 1408.

[0040] Although hydraulically actuated pistons have been used to demonstrate Figure 14 and Figure 15The implementation scheme described herein is provided, but it should be understood that the retractable piston described herein can be actuated using other means known to those skilled in the art.

[0041] Although specific preferred embodiments have been shown and described, those skilled in the art will understand that changes and modifications can be made without departing from this teaching. For example, while the specific implementations of the aerodynamic components described herein are primarily of the mechanical locking type, it should be understood that the aerodynamic components can be modified to be based on hydraulic locking systems, such as hydraulic clearance adjusters (HLA) or control valves as known in the art. In this case, similar to Figure 2 In some implementation schemes, the stroke limiting feature can be integrated into the hydraulic locking component. For example, when the hydraulic locking component is implemented as an HLA, a check ball actuation feature can be provided, which allows the HLA to fold (or unlock) as needed, thereby eliminating venting events. In this case, the stroke limiting feature can be designed into the HLA between the body and the plunger component. Additionally, according to the above description relative to... Figure 3 In the alternative embodiment described, the travel limiting feature may be located on the outside of the HLA folding element.

[0042] Furthermore, while the above description focuses on providing high-lift transfer components for the purpose of providing fail-safe lift, those skilled in the art will understand that the teachings described herein also offer other advantages. For example, with CDA systems, it is known that under certain operating conditions, the pressure in the combustion chamber in deactivated mode can become negative, causing oil to be drawn through these rings and consumed in the combustion chamber. The teachings described herein can be used to rebalance the pressure in the cylinders in each cycle by allowing the high-lift transfer components to open valves to allow intake or exhaust pressure to enter, thereby maintaining positive pressure and minimizing fuel consumption, while still allowing the engine to operate in CDA mode to achieve the other mentioned benefits.

[0043] Furthermore, although the aerodynamic components and high-lift transmission components have been discussed in the context of CDA operation in the above description, those skilled in the art should understand that this disclosure need not be limited in this respect. For example, such components can also be used in engine braking systems that require interruption of main valve events, such as the "HPD" engine braking technology developed by Jacobs Vehicle Systems, Inc.

[0044] Therefore, it can be expected that any and all modifications, variations or equivalents of the above teachings fall within the scope of the basic principles disclosed above and the protections claimed herein.

Claims

1. A valve actuation system comprising a valve actuation motion source configured to provide a primary event valve actuation motion to at least one engine valve via a primary motion load path comprising at least one valve train component, the valve actuation system further comprising: a lost motion component disposed within the at least one valve train component, the lost motion component being controllable to operate in a motion transfer state in which the lost motion component transfers the primary event valve actuation motion to the at least one engine valve, and to operate in a motion absorption state in which the lost motion component does not transfer at least a portion of the primary event valve actuation motion to the at least one engine valve during an engine braking operation of the valve actuation system; and a high-lift transfer component disposed to operate entirely within the primary motion load path, the high-lift transfer component being configured to transfer at least a high-lift portion of the primary event valve actuation motion to the at least one engine valve when the lost motion component is in the motion absorption state.

2. The valve actuation system of claim 1, wherein the high-lift transfer component is incorporated into the lost motion component.

3. The valve actuation system of claim 2, wherein the high-lift transfer component comprises a stroke limiter.

4. The valve actuation system of claim 3, wherein the lost motion component comprises a mechanical lock subsystem.

5. The valve actuation system of claim 3, wherein the lost motion component comprises a hydraulic lock subsystem.

6. The valve actuation system of claim 2, wherein the high-lift transfer component comprises an auxiliary lock subsystem.

7. The valve actuation system of claim 1, wherein the at least one valve train component comprises a valve bridge.

8. The valve actuation system of claim 1, wherein the at least one valve train component comprises a rocker arm.

9. The valve actuation system of claim 1, wherein the at least one valve train component comprises a push rod.

10. The valve actuation system of claim 1, wherein the high-lift transfer component is incorporated into the at least one valve train component.

11. The valve actuation system of claim 10, wherein the high-lift transfer component comprises a stroke limiter.

12. The valve actuation system of claim 11, wherein the stroke limiter comprises at least one contact surface disposed on the at least one valve train component.

13. The valve actuation system of claim 12, wherein the at least one contact surface comprises a retractable piston.

14. The valve actuation system of claim 10, wherein the at least one valve train component comprises a valve bridge.

15. The valve actuation system of claim 10, wherein the at least one valve train component comprises a rocker arm.

16. The valve actuation system of claim 10, wherein the at least one valve train component comprises a push rod. ​

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