KR20230169369A - A valve actuating system comprising a prerocker arm valve train component and a series lost motion component disposed in a valve bridge. - Google Patents

Abstract

The valve actuation system includes a valve actuation motion source configured to provide a main valve actuation motion and an auxiliary valve actuation motion for actuating at least one engine valve through a valve actuation load path. The lost motion reduction mechanism is arranged in the prerocker arm valve train component and, in a first default operating state, is configured to transmit at least the main valve operating motion and, in the first activated state, transmit the main valve operating motion and the auxiliary valve operating motion. It is designed to be lost. Additionally, a lost motion adding mechanism is arranged in the valve bridge, and is configured, in a second default operating state, to disable the auxiliary valve actuating motion and, in a second activated state, to transmit the auxiliary valve actuating motion, wherein: The motion adding mechanism is in series with the lost motion subtracting mechanism in the valve operating load path.

Description

A valve actuating system comprising a prerocker arm valve train component and a series lost motion component disposed in a valve bridge.

The present disclosure relates generally to valve actuation systems, and more particularly to a valve actuation system comprising a lost motion component in series along a valve actuation load path, the valve actuation system comprising a cylinder deactivator and an auxiliary valve. It can also be used to implement both operations.

BACKGROUND OF THE INVENTION Valve actuation systems for use in internal combustion engines are well known in the art. During positive power operation of an internal combustion engine, such a valve actuation system applies a so-called main valve actuation motion to the engine valves, in conjunction with combustion of fuel, such that the engine outputs power that may be used, for example, to operate the vehicle. It is used to provide Alternatively, the valve actuation system may be operated to provide so-called auxiliary valve actuation motion in addition to or in addition to the main valve actuation motion. The valve actuation system may also operate in a manner that completely stops the operation of a given engine cylinder, i.e., does not operate in the main mode of operation or in the auxiliary mode of operation through the elimination of any engine valve actuation, often referred to as cylinder deactivation. It could be. As is further known in the art, these various modes of operation may be combined to provide desirable benefits. For example, future emissions standards for heavy duty diesel trucks will require technologies that improve fuel efficiency and reduce exhaust emissions. The leading technology that provides both simultaneously is cylinder deactivation. It is well documented that cylinder deactivation reduces fuel consumption and increases temperatures providing improved aftertreatment exhaust control.

A known system for cylinder deactivation is described in U.S. Patent No. 9,790,824, which describes a hydraulically controlled lost motion mechanism disposed in a valve bridge, an example of which is illustrated in Figure 11 of the '824 patent. Reproduced herein as Figure 1. As shown in FIG. 1 , the lost motion mechanism includes an external plunger 120 disposed with a bore 112 formed in the body 110 of the valve bridge 100 . A locking element in the form of a wedge 180 is provided, which wedge is configured to engage with an annular external recess 172 formed in the surface defining the bore 112 . In the absence of hydraulic control applied to the inner plunger 160 (in this case via a rocker arm, not shown), the inner piston spring 144 forces the wedge 180 out of the opening formed in the outer plunger 120. expands, thereby biasing the inner plunger 160 into a position that engages the outer recess 172 and effectively locks the outer plunger 120 in position relative to the valve bridge body 110 . In this state, any valve actuating motion (whether main or auxiliary motion) applied to the valve bridge via the external plunger 120 is directed to the valve bridge body 110 and ultimately to the engine valves (not shown). It is delivered. However, provision of sufficiently pressurized hydraulic fluid to the top of the inner plunger 160 causes the inner plunger 160 to slide downward, causing the wedge 180 to contract and separate from the outer recess 172. Thereby effectively unlocking the external plunger 120 relative to the valve bridge body 110 and subjecting the external plunger 120 to the bias provided by the external plunger spring 146 towards the rocker arm, thereby forcing the external plunger 120 into the bore 112. ) is allowed to slide freely within the In this state, any valve actuation motion applied to external plunger 120 will cause external plunger 120 to reciprocate within bore 112. In this way, and assuming that the movement of the external plunger 120 within the bore 112 is greater than the maximum extent of any applied valve actuation motion, such valve actuation motion is not transmitted to the engine valves and effectively is lost and the corresponding cylinder is deactivated.

However, one drawback of cylinder deactivation is that the flow of air mass through the engine is reduced, thus also reducing energy in the exhaust system. During vehicle warm-up from a cold start, it is important to have an elevated exhaust temperature to quickly raise the catalyst temperature to the efficient operating temperature. Although cylinder deactivation provides increased temperatures, the significant reduction in air mass flow makes it ineffective for rapid warm-up.

To overcome these disadvantages of cylinder deactivation and provide rapid warm-up, one proven technique is to advance the opening of the exhaust valves to dissipate the added heat energy into the exhaust system, known as early exhaust valve opening (EEVO). This is a specific type of auxiliary valve actuation motion other than the main valve event. In practice, such systems are based on the principle of adding valve actuation motion that would otherwise be lost during main valve actuation to provide for this early opening event. Systems that combine both early exhaust opening and cylinder deactivation performance can meet preheating requirements and provide reduced emissions and improved fuel consumption.

A valve actuation system for providing EEVO may be provided using a rocker arm with a hydraulically controlled lost motion component in the form of an actuator, for example as exemplified in U.S. Pat. No. 6,450,144, an example of which is shown in the figure in the '824 patent. 19 and reproduced herein as Figure 2. In this system, a rocker arm 200 is provided with an actuator piston 210 disposed at the motion transmitting end of the rocker arm 200. The actuator piston 210 is biased out of the bore by a spring 217 such that the actuator piston 210 is in continuous contact with the corresponding engine valve (or valve bridge). Hydraulic passages 231 and 236 are provided so that hydraulic fluid can be provided by the control passage 211 to fill the actuator piston bore. In these situations, hydraulic fluid is retained in the bore by virtue of the check valve 241 and unless the hydraulic passage 236 is aligned with the control passage 211, in which case the actuator piston 210 remains rigid in the extended position. It is maintained and cannot reciprocate within the bore. On the other hand, if the bore is not filled with hydraulic fluid (or if such fluid is evacuated upon alignment of the passages 236, 211), the actuator piston 210 is attached to the lash adjusting screw 204. It can freely reciprocate within the bore to the extent permitted by the bore. In such systems, the cam includes cam lobes to provide both main and auxiliary valve actuation motion. In the main valve actuation operation, no hydraulic fluid is provided to the actuator piston 210 to enable the actuator piston 210 to reciprocate within the bore. In this case, then, as long as the allowed movement of the actuator piston 210 into the bore is at least as great as the maximum motion provided by the EEVO lobe, but less than the maximum motion provided by the main event lobe, Any valve actuation motion provided by the actuating piston 210 will be lost through the reciprocating motion of the actuating piston 210, but the main event valve actuation will cause the actuating piston 210 to move within the bore (or through solid contact with some other surface). ) will touch the bottom, thereby delivering the main event motion. On the other hand, if the actuator piston is hydraulically locked in its extended position, the EEVO motion is not lost and is transmitted to the engine valves, but the exhaust based on the position of the actuator bore (i.e. the alignment of the mentioned passages 236, 211) (via reset) prevents over-extension of engine valves during main valve event motion.

It should be at least theoretically possible to combine a lost motion based cylinder deactivation and auxiliary valve actuation motion system of the type described above to provide the desired cylinder deactivation and EEVO operation. However, it is not a given that simply combining such systems directly will provide the desired results.

For example, as described above, EEVO lost motion combines normal main event lift with an early raised portion on the same camshaft. An example of this is illustrated in Figure 3. In Figure 3, the first curve 310 illustrates that the ideal version of the main event valve lift, in this example, has a maximum lift of approximately 14 millimeters. The second curve 311 illustrates a typical real-world key event as experienced by an engine valve, when any EEVO motion provided by the cam is lost, e.g. This will occur when the rocker arm actuator is allowed to reciprocate. The top dashed curve 312 illustrates the ideal valve lift given all of the valve actuation motion provided by the EEVO-capable cam, e.g., when the rocker arm actuator is fully extended. do. As shown, the ideal lift 312 includes an EEVO event 313 of approximately 3 mm of valve lift, which actually translates into a valve lift 314 of approximately 2 millimeters during valve opening. The example illustrated in FIG. 3 also illustrates the occurrence of a reset, whereby the actuator piston collapses, in this example, at approximately 10 mm of lift (i.e., the hydraulic fluid trapped within the actuator bore causes the engine valve to collapse). discharged during the cycle) is allowed, thereby causing the normal lift main event 311 to occur. The combination of these two lift events (as illustrated by ideal lift profile 312) results in a total stroke of approximately 17 mm, which when lost by the lost motion mechanism illustrated in FIG. Because it attempts to deflect the outer plunger 120 throughout its total 17 mm of movement, it will exert relatively high stresses on the outer plunger spring 146.

As a further example, during cylinder deactivation as described above, the normal force applied by the engine valve springs to bias the rocker arm into continuous contact with the valve actuating motion source (e.g., cam) is no longer provided. It is known that it does not. Although the outer piston plunger spring 146 provides some force back toward the rocker arm through the outer plunger 120, this force is relatively small and insufficient to control the rocker arm as required. Accordingly, a separate rocker arm biasing element is typically used to bias the rocker arm into contact with the cam, for example, by applying a biasing force to the motion receiving end of the rocker arm toward the cam via a spring positioned on the rocker arm. provided. Failure to properly control the inertia provided by the rocker arm (due to the valve actuating motion still being applied to the rocker arm despite its deactivation) can lead to separation between the rocker arm and the cam and, ultimately, between the two. It may lead to a damaging impact. Likewise, the EEVO valve actuation motion that would otherwise be lost when EEVO action is not needed still transfers inertia to the rocker arm, which must be similarly controlled. A complicating factor for such operations by rocker arm biasing elements is that each of these operations - cylinder deactivation and EEVO - typically occurs at significantly different speed ranges.

In general, cylinder deactivation typically occurs at engine speeds below approximately 1800 rpm and the rocker arm biasing element is configured to provide sufficient force at these speeds to ensure proper contact between the rocker arm and the cam. On the other hand, otherwise lost EEVO valve actuation motion will exist even up to high engine speeds (e.g., approximately 2600 rpm). Therefore, to obtain the benefits of combined cylinder deactivation and EEVO operation, the rocker arm biasing element will need to accommodate the higher velocities at which EEVO valve actuation motion may still be applied to the rocker arm. Due to the relatively high speeds at which they may still occur, rocker arm control of the lost EEVO valve actuation motion requires application of high forces by the rocker arm biasing elements. However, this occurs at small valve lifts where the rocker arm biasing spring has its lowest preload. On the other hand, cylinder deactivation generally occurs at lower speeds and throughout the higher lift portion (main valve actuation motion) where the rocker arm biasing elements are at increased preload. However, it is capable of both providing high forces at the lowest preload (as required by EEVO) and withstanding the stresses required during the entire travel (as required by cylinder deactivation). The challenge of providing rocker arm biasing elements is difficult to overcome.

The above-mentioned disadvantages of the prior art solutions are solved through the provision of a valve actuation system for actuating at least one engine valve according to the present disclosure. In particular, the valve actuation system includes a valve actuation motion source configured to provide a main valve actuation motion and an auxiliary valve actuation motion for actuating at least one engine valve through a valve actuation load path. A lost motion subtracting mechanism is arranged in the pre-rocker arm valve train component and is configured to, in a first default operating state, transmit at least the main valve actuation motion, the first In the activated state, it is configured to lose the main valve actuation motion and the auxiliary valve actuation motion. Additionally, a lost motion adding mechanism is arranged in the valve bridge, and is configured, in a second default operating state, to disable the auxiliary valve actuating motion and, in a second activated state, to transmit the auxiliary valve actuating motion, wherein: The motion adding mechanism is in series with the lost motion subtracting mechanism in the valve operating load path.

Examples of auxiliary valve actuation motions include early exhaust valve opening valve actuation motion, late intake valve closing valve actuation motion, or engine braking valve actuation motion. actuation motion).

In one embodiment, the valve actuation system further includes an engine controller configured to operate the internal combustion engine using a lost motion reduction mechanism and a lost motion addition mechanism. In the positive power mode, the engine controller controls the lost motion reduction mechanism to operate in a first default operating state and the lost motion adding mechanism to operate in a second default operating state. In the deactivated mode, the engine controller controls the lost motion reduction mechanism to operate in a first activated operating state and the lost motion adding mechanism to operate in a second default operating state. In the auxiliary mode, the engine controller controls the lost motion reduction mechanism to operate in a first default operating state and the lost motion adding mechanism to operate in a second activated operating state.

A corresponding method is also disclosed.

The features described in this disclosure are set forth in detail in the appended claims. These features and accompanying advantages will become apparent from consideration of the following detailed description, taken in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings, wherein like reference numerals indicate like elements, in which:
1 illustrates a lost motion mechanism suitable for providing cylinder deactivation according to the prior art;
Figure 2 illustrates a lost motion mechanism suitable for providing auxiliary valve actuation according to the prior art;
3 is a graph illustrating an example of EEVO valve actuation motion according to the present disclosure;
4 and 5 are schematic illustrations of embodiments of a valve actuation system according to the present disclosure;
Figure 6 illustrates a partial cross-sectional view of an embodiment of a valve actuation system according to the embodiment of Figure 4;
Figure 7 is an exploded view of a reset rocker arm according to the embodiment of Figure 6;
Figures 8-11 are partial top and cross-sectional side views, respectively, of a reset rocker arm according to the embodiment of Figures 6-8;
Figure 12 is a partial cross-sectional view of a first embodiment of a valve actuation system according to the embodiment of Figure 5;
Figure 13 is a partial cross-sectional view of a second embodiment of the valve actuation system according to the embodiment of Figure 5;
14 is a flow chart illustrating a method of operating an internal combustion engine according to the present disclosure;
Figure 15 is a schematic illustration of an embodiment of a valve actuation system according to a variant of the valve actuation system depicted in Figure 4 and according to the present disclosure;
Figure 16 is a side view of an embodiment of a valve actuation system according to the embodiment of Figure 15;
Figure 17 is a side cross-sectional view of the embodiment according to Figure 16; and
Figure 18 is a side cross-sectional view of the LM+ mechanism of Figure 17 illustrated in more detail.

4 schematically illustrates a valve actuation system 400 according to the present disclosure. In particular, valve actuation system 400 includes a valve actuation motion source (i.e., valve opening and closing motion) that functions as the sole source of valve actuation motion (i.e., valve opening and closing motion) for one or more engine valves 404 via valve actuation load path 406. 402). One or more engine valves 404 are associated with cylinders 405 of an internal combustion engine. As is known in the art, each cylinder 405 typically has at least one uniquely corresponding valve actuating motion source 402 for actuation of the corresponding engine valve(s) 404. . Moreover, although only a single cylinder 405 is illustrated in FIG. 4, an internal combustion engine may, and often does, include more than one cylinder, and the valve actuating system described herein can be configured to accommodate any number of cylinders for a given internal combustion engine. It is recognized that it is applicable to cylinders.

Valve actuation motion source 402 may include any combination of known elements capable of providing valve actuation motion, such as cams. Valve actuated motion source 110 may be dedicated to providing exhaust motion, intake motion, auxiliary motion, or a combination of exhaust or intake motion along with auxiliary motion. For example, in a presently preferred embodiment, valve actuation motion source 402 may include a single cam configured to provide a main valve actuation motion (exhaust or intake) and at least one auxiliary valve actuation motion. As a further example, if the main valve actuation motion includes a main exhaust valve actuation motion, the at least one auxiliary valve actuation motion may include an EEVO valve event and/or a compression release engine brake valve event. As still a further example, if the main valve actuation motion includes a main intake valve actuation motion, the at least one auxiliary valve actuation motion may include a late intake valve closing (LIVC) valve event. Still further types of auxiliary valve actuation motions that can be combined on a single cam with the main valve actuation motion may be known to those skilled in the art, and the present disclosure is not limited in this regard.

The valve actuation load path 406 is disposed between the valve actuation motion source 402 and at least one engine valve 404 and directs the motion provided by the valve actuation motion source 402 to the at least one engine valve 404. Includes any one or more components used for transmission, such as tappets, pushrods, rocker arms, valve bridges, automatic lash adjusters, etc. Additionally, as shown, the valve actuation load path 406 also includes a lost motion adding (LM+) mechanism 408 and a lost motion subtracting (LM-) mechanism 410. As used herein, an LM+ mechanism is a state in which the mechanism does not transmit any auxiliary valve actuation motion applied to it and may or may not transmit any main valve actuation motion applied to it (i.e., control input This is the mechanism that defaults to (if not declared) or is "normally" in that state. On the other hand, when the LM+ mechanism is in the activated state (i.e. when a control input is asserted), the mechanism transmits any auxiliary valve actuation motion applied to it and also any main valve actuation motion applied to it. Also conveys . Moreover, as used herein, LM-mechanism refers to a state in which the mechanism transmits any main valve actuation motion applied to it and may or may not transmit any auxiliary valve actuation motion applied to it (i.e. , if no control inputs are declared), or is a mechanism that is "normally" in that state. On the other hand, if the LM-mechanism is in the activated state (i.e. a control input is asserted), the mechanism will not perform any valve actuation motion applied to it, whether the main valve actuation motion or the auxiliary valve actuation motion. Doesn't deliver. Simply put, the LM+ mechanism, when activated, can add or include valve actuation motion relative to its default or normal operating state, while the LM- mechanism, when activated, can add or include valve actuation motion relative to its default or normal operating state. Valve actuation motion may be reduced or lost relative to normal operating conditions.

Various types of lost motion mechanisms that can function as LM+ or LM- mechanisms are well known in the art, including hydraulically or mechanically based lost motion mechanisms that may also be hydraulically, pneumatically, or electromagnetically actuated. For example, the lost motion mechanism depicted in FIG. 1 and taught in U.S. Pat. No. 9,790,824 (the teachings of which are incorporated herein by this reference) is an example of a hydraulically controlled mechanical locking LM-mechanism. As described above, in the absence of hydraulic fluid input to the internal plunger 160 (i.e., in the default state), the locking element 180 is received in the external recess 772, thereby causing the locking element 180 to be applied to itself. “Locking” the external plunger 120 to the body 120 so that actuation motion is transmitted. On the other hand, when hydraulic fluid input is provided to the internal plunger 160 (i.e. in an activated state), the locking element 180 is allowed to retract, thereby not transmitting the actuating motion applied to it. “Unlocking” the outer plunger 120 from the body 120 so that it is unlocked or lost. As another example, the lost motion mechanism depicted in FIG. 2 and taught in U.S. Pat. No. 6,450,144, the teachings of which are incorporated herein by this reference, is an example of a hydraulically controlled, hydraulically based LM+ mechanism. As described above, in the absence of hydraulic fluid input to passages 231 and 236 (i.e., in the default state), the actuator piston 210 has a maximum distance that the actuator piston 210 can be retracted into the bore ( within its bore so that any actuating motion applied to itself smaller than the stroke length of the actuator piston is not transmitted or is lost, while any actuating motion applied to itself larger than the stroke length of the actuator piston is transmitted. freely reciprocates in

As further depicted in FIG. 4 , an engine controller 420 may be provided and operably connected to the LM+ and LM- mechanisms 408 , 410 . The engine controller 420 may be configured with any electronic device for controlling the operation of the LM+ and LM- mechanisms 408, 410, i.e., for switching between their respective default and activated operating states as described above. , may include mechanical, hydraulic, electro-hydraulic, or other types of control devices. For example, engine controller 420 may be implemented by a microprocessor and corresponding memory storing executable instructions used to implement the necessary control functions, including those described below, as is known in the art. It can be implemented. It is recognized that other functionally equivalent implementations of engine controller 130, such as a suitable programmed application specific integrated circuit (ASIC) or otherwise, may equally be utilized. In addition, the engine controller 420 is configured to control the operating states of the LM+ and LM- mechanisms 408, 410, which allows the engine controller 420 to realize control over the operating states of the LM+ and LM- mechanisms 408, 410. , 410) may include a peripheral device in the middle. For example, if both LM+ and LM- mechanisms 408, 410 are hydraulically controlled mechanisms (i.e., respond to the absence or application of hydraulic fluid to input), such peripheral devices are known in the art. As shown, a suitable solenoid may be included.

In the system 400 illustrated in FIG. 4 , the LM+ mechanism 408 is arranged closer to the source of valve actuation motion along the valve actuation load path 406 than the LM- mechanism 410 . An example of such a system is described in more detail below with reference to FIGS. 6-12. However, this is not required. For example, FIGS. 5 and 15 illustrate valve actuation systems 400', 1500 with like reference numerals indicating similar elements compared to FIG. 4, where LM- mechanisms 410, 410' are referred to as LM+ mechanisms ( arranged closer to the valve actuating motion source 402 than 408, 408'). An example of the system of FIG. 5 is described in more detail below with reference to FIGS. 12 and 13, and one example of the system of FIG. 15 is described in more detail below with reference to FIGS. 16-18.

Referring back to Figure 4, LM+ mechanism 408 is in series with LM- mechanism 410 along valve actuation load path 406 in all operating states of LM+ mechanism 408. That is, whether the LM+ mechanism 408 is in its default state or its activated state as described above, any main valve actuation motion provided by the valve actuation motion source 402 is the LM+ mechanism. It is transmitted to the LM-mechanism 410 by 408. However, once again, this is not required, as illustrated in Figure 5 where LM+ mechanism 408 is illustrated in series or non-series with LM- mechanism 410 as a function of the operating state of LM+ mechanism 408. In this case, when the LM+ mechanism 408 is in its default operating state, i.e. when it is controlled to lose any auxiliary valve actuation motion applied to it, the LM+ mechanism 408 ) does not serve to transmit the main valve operating motion transmitted by ; This is illustrated by the solid arrow between the LM-mechanism 410 and the engine valve(s) 404. In fact, in this state, the LM+ mechanism 408 is removed from the valve actuation load path 406 as depicted in FIG. 5 . On the other hand, when the LM+ mechanism 408 is in its activated state of operation, i.e. when it is controlled to transmit any auxiliary valve actuation motion applied to it, the LM+ mechanism 408 participates in the transmission of both the main valve actuation motion and the auxiliary valve actuation motion received from 410), thereby effectively placing the LM+ mechanism 408 in series with them; This is illustrated by the dashed arrows between the LM- mechanism 410 and the LM+ mechanism 408, and the LM+ mechanism 408 and the engine valve(s) 404.

The valve actuation systems 400, 400' of FIGS. 4 and 5 include a positive power mode of the system with a single valve actuation motion source 402 providing all valve actuation motion to the engine valve(s) 404; In the deactivated mode or auxiliary mode, it facilitates the operation of the cylinder 405, and consequently the internal combustion engine. This is further explained with reference to the method illustrated in Figure 14. At block 1402, the LM+ and LM- mechanisms are arranged in the valve actuation load path, as described above. In particular, the LM-mechanism is configured to transmit, in a first default operating state, at least the main valve actuation motion applied to it and, in the first activated state, any main valve actuation motion and auxiliary valve actuation motion applied to it. It is configured to lose actuation motion. Additionally, the LM+ mechanism is configured to, in a second default operating state, lose any auxiliary valve actuation motion applied to it and, in a second activated state, to transmit auxiliary valve actuation motion, wherein LM+ The mechanism is in series with the LM-mechanism in the valve actuating load path at least during the second activated state.

After providing the valve actuation system at step 1402, processing proceeds to any of blocks 1406-1410, where the engine is placed in positive power mode, deactivated, or activated based on control of the operating states of the LM+ and LM- mechanisms. It operates in each mode or auxiliary mode. Accordingly, at block 1406, the LM- mechanism is placed in a first default operating state and the LM+ mechanism is placed in a second default operating state to operate the engine in positive power mode. Then, in this mode, the LM+ mechanism will not transmit any auxiliary valve actuation motion, but will, however, be transmitted by the LM- mechanism (whether the LM+ mechanism is arranged as in Fig. 4 or as in Fig. 5). Depending on whether or not) any main valve operating motion can be transmitted. The net effect of this configuration is that only the main valve actuation motion is transmitted to the engine valve(s), as required for positive power operation.

At block 1408, to operate the engine in a disabled mode, the LM-mechanism is placed in its first activated operating state and the Lost Motion Addition mechanism is placed in its second default operating state. Then, in this mode, the LM-mechanism will not transmit any valve actuating motion applied to it. As a result, the corresponding cylinder will be deactivated to the extent that no valve actuation motion will be transmitted to the engine valve(s). Considering this operation of the LM- mechanism, the operating state of the LM+ mechanism will not have any effect on the engine valve(s). However, in the presently preferred embodiment, during deactivated mode operation, the LM+ mechanism is placed in its second default operating state.

At block 1410, the LM- mechanism is placed in its first default operating state and the LM+ mechanism is placed in its second activated operating state to operate the engine in the secondary mode. Then, in this mode, the LM+ mechanism will transmit any auxiliary valve actuation motion and any main valve actuation motion transmitted by the LM- mechanism. The net effect of this configuration is that both the main valve actuation motion and the auxiliary valve actuation motion are transmitted to the engine valve(s), thereby causing certain auxiliary valve actuation motions, e.g. EEVO, LIVC, decompression engine braking, etc. It provides any auxiliary operation provided by .

Operation of the engine between any of the various modes provided in steps 1406-1410 may continue as long as the engine is running, as illustrated by block 1412.

FIG. 6 illustrates a partial cross-sectional view of a valve actuation system 600 according to the embodiment of FIG. 4 . In particular, system 600 includes a valve actuated motion source 602 in the form of a cam operably connected to rocker arm 604 at a motion-receiving end 606 of rocker arm 604. A rocker arm biasing element 620 (e.g., a spring) responsive to the fixed surface 622 may be provided to help bias the rocker arm 604 into contact with the valve actuating motion source 602. . As is known in the art, rocker arm 604 rotates and reciprocates about a rocker shaft (not shown), thereby, through motion transfer end 608 of rocker arm 604, actuating the valve. The valve actuation motion provided by the motion source is transmitted to the valve bridge 610. Ultimately, valve bridge 610 is operably connected to a pair of engine valves 612, 614. As further shown, the valve bridge 610 includes an LM-mechanism 616 (locking piston) of the type illustrated and described in Figure 1 above, while the rocker arm 604 is associated with Figure 2. thus comprising an LM+ mechanism 618 (actuator) of a type substantially similar to that illustrated and described above.

Details of the LM+ mechanism 618 are further illustrated in FIG. 7 along with other components arranged within the rocker arm 604. The LM+ mechanism 618 includes an actuator piston 702 attached to a retainer 703 such that the actuator piston 702 is slidably arranged on the lash adjustment screw 704. Additional details of the LM+ mechanism 618 are described with reference to Figure 9 below. As best shown in FIG. 9 , lash adjustment screw 704 is threadedly secured to actuator piston bore 710 such that LM+ mechanism 618 is arranged in the lower portion of actuator piston bore 710 . A locking nut 704 is provided to secure the lash adjustment screw 704 at the desired lash setting during its use.

7 also illustrates a reset assembly 712 arranged within a reset assembly bore 724 that includes openings on the top and bottom (not shown) of the rocker arm 604. Reset assembly 712 includes a reset piston 714 slidably arranged within a reset assembly bore 724. Reset piston spring 715 is arranged above reset piston 714 and the lower end of reset piston spring 716 is secured to reset piston 714 using a c clip 718 or other suitable component. A washer 720 is arranged at the upper end of the reset piston spring 716. Reset assembly 712 is retained within reset assembly bore 724 by a spring clip 722, as is known in the art. As explained in greater detail below in connection with FIGS. 10 and 11 , reset piston spring 716 is configured to provide a reset assembly so that reset piston 714 can contact a fixed surface (not shown in FIG. 7 ). Deflects reset piston 714 out of the lower opening of bore 724. As rocker arm 604 reciprocates, reset piston 714 slides within reset assembly bore 724 in a controllable manner influenced by the rotation of rocker arm 604. In particular, at the desired position of the rocker arm 604, the reset piston 714 has an annular channel 715 formed in the reset piston to effect reset of the LM+ mechanism 618, as explained in more detail below. This may be configured to align with reset passage 802 (FIG. 8).

7 further illustrates an upper hydraulic passage 730 formed in rocker arm 604 that houses check valve 732. As explained in more detail below, the upper hydraulic passage 730 provides hydraulic fluid (provided by a suitable supply passage formed in the rocker shaft) to the actuator piston bore 710 to control the operation of the LM+ mechanism 618. (not shown) is provided. A threaded plug 734 or similar device may be utilized to ensure a fluid-tight seal of the upper hydraulic passage 730 following installation of the check valve 732. Additionally, for completeness, FIG. 7 also illustrates a rocker arm bushing 740 that can be inserted within the rocker shaft opening 742 and over the rocker shaft, as is known in the art. Additionally, a cam follower 744 may be mounted on a cam follower axle 746 arranged within a suitable opening 748.

However, unlike the actuator piston 210 of FIG. 2, and as best illustrated in FIG. 9, the actuator piston 702 of the LM+ mechanism 618 allows hydraulic fluid to flow through the actuator piston 702 into the LM- Hydraulic passages 904 and 906 allow for supply to mechanism 616. As shown in FIG. 9 , the lower hydraulic passage 908 formed in the rocker arm 604 receives hydraulic fluid from a supply channel of the rocker shaft (not shown) and directs the hydraulic fluid to the lower portion of the actuator piston bore 710. Route into parts. The actuator piston 702 includes an annular channel 910 formed in its side wall surface, which is aligned with a hydraulic supply passage 908 throughout the entire stroke of the actuator piston 702. Ultimately, the annular channel 910 communicates with the horizontal passage 904 and the vertical passage 906 formed in the actuator piston 702. The vertical passage 906 guides the hydraulic fluid to the swivel 706, which has an opening formed therein for passage of the hydraulic fluid to the LM-mechanism 616. In this way, hydraulic fluid can be selectively supplied as a control input to the LM-mechanism 616.

As described above and further shown in FIG. 9 , the LM+ mechanism 618 includes a lash adjustment screw 704 that extends into the actuator piston bore 710 . The actuator piston spring 918 is disposed between the lash adjustment screw 704 and the actuator piston 702 and abuts the lower surface of the shoulder 920 formed by the lash adjustment screw 704, thereby adjusting the actuator piston 702 Deflects out of the actuator piston bore 710. In this embodiment, the actuator piston 702 is secured to a retainer 703 that engages the upper surface of the lash adjustment screw shoulder 920, through an appropriate screw engagement, thereby as described in more detail below. , limiting the outward stroke of the actuator piston 702.

8 and 9 show an upper section formed in the rocker arm 604 to selectively supply hydraulic fluid (e.g., via a high-speed solenoid, not shown) to the actuator piston bore 710 above the actuator piston 702. A hydraulic passage 730 is further illustrated (phantom line in FIG. 9 ). (Note that in FIG. 8 , the various components forming the LM+ mechanism 618 and reset assembly 712 are not shown, for ease of illustration.) The check valve 732 is connected to the actuator piston bore 710. To prevent reverse flow of hydraulic fluid back to the supply passage that supplies the upper hydraulic passage 730, an expanded portion 730' of the upper hydraulic passage 730 is provided. In this way, and without resetting of the LM+ mechanism 618 as described below, the confinement volume of hydraulic fluid is compressed into the actuator piston bore 710 such that the actuator piston 702 remains in the extended (enabled) state. ) A high pressure chamber may be formed between the check valve 732 and the actuator piston 702.

As described above with respect to FIG. 3 , a valve actuation system in which a single source of valve actuation motion provides both main and auxiliary valve actuation motion can be used to reduce excessive pressure on the engine valve(s) during the combined auxiliary and main valve actuation motion. May require the ability to reset to prevent expansion. In the context of the embodiment illustrated in FIGS. 6-11 , discharge of the trapped volume of hydraulic fluid and resetting of the actuator piston 702 is provided through operation of the resetting assembly 712 . As best shown in FIG. 8 , a portion of the actuating piston bore 710 forms a high pressure chamber with the actuator piston 702, and a reset passage 802 is in fluid communication with the reset piston bore 804. . Reset piston 714 is essentially a spool valve having an end that extends out of the bottom of rocker arm 604 under the bias of reset piston spring 716. 10 and 11 , reset piston 714 has sufficient length and reset piston spring 716 is such that reset piston 714 is in fixed contact throughout all positions of rocker arm 604. It has sufficient stroke to ensure continuous contact with surface 1002.

As shown in FIG. 10 , rocker arm 604 is in base circle relative to cam 602 (i.e., rotated to its full extent toward cam 602). In this condition, as well as at relatively low lifts (e.g., below the reset height shown in Figure 3), the outer diameter of the reset piston 714 seals communication with the reset passage 802, thereby allowing fluid (providing An annular channel 715 is located in reset passage 802 (hidden behind upper hydraulic passage 730 as shown in FIGS. 10 and 11 ) to retain the captured volume of the actuator piston bore 710 (if present) in the actuator piston bore 710. is not aligned with As shown in FIG. 11 , when the rocker arm 604 rotates at a higher valve lift (e.g., above the reset height shown in FIG. 3), the reset piston 714 contacts the stationary surface 1002. By pivoting about the point of contact and sliding relative to the reset piston bore 804, the annular channel 715 is aligned with the reset passage 802, thereby allowing captured hydraulic fluid to flow through the annular channel 715 into the reset piston. Allows flow into radial hole 1004 formed at 714 and exit through the top of axial passage 1006 (shown in phantom) formed at reset piston 714. 10 , as rocker arm 604 rotates back once again following a high lift event, reset piston 714 translates within its bore 804 and opens reset passageway 802 again. once sealed, thereby allowing refilling of the actuator piston bore 710.

As mentioned above, reset assembly 712 illustrated in FIGS. 6-11 is configured to maintain constant contact with fixed contact surface 1002. However, it is recognized that this is not required. For example, the reset assembly may instead include a poppet-type valve that contacts a fixed surface only when the required reset height is achieved.

As previously mentioned, a rocker arm biasing element 620 may be provided to help bias the rocker arm 604 into contact with the cam 602. A feature of the disclosed system 600 is that, individually, neither the rocker arm biasing element 620 nor the actuator piston spring 918 keeps the rocker arm 604 in contact with the cam 602 throughout substantially all operating conditions. They are not individually configured to provide sufficient force to deflect. However, rocker arm biasing element 620 and actuator piston spring 918 are, in this embodiment, selected to operate in combination for this purpose across substantially all operating conditions for rocker arm 604. For example, to help bias the rocker arm 604 toward the cam 602, the actuator piston spring 918 exerts high forces, resulting in relatively low lift valve actuation when it is most needed due to the potential high speed operation. Provided only during motion (e.g. EEVO, LIVC, etc.). If uncontrolled, the biasing force applied by the actuator piston spring 918 can cause the actuator piston 702 to push against the LM-mechanism 616 with significant force. If LM-mechanism 616 is a mechanical locking mechanism such as that described with reference to FIG. 1 , such force may be strong enough to interfere with the ability of locking element 180 to expand and retract, thereby locking the LM-mechanism. Locking and unlocking of (616) can be prevented. The travel restrictions imposed by the lash adjustment screw shoulder 920 on the actuator piston 702 prevent such excessive loading on the LM-mechanism 616, thereby allowing the locking element 180 to extend freely as required. /Preserves the normally provided lash space within the LM-mechanism 616 to allow for retraction.

Additionally, the expansion of the actuator piston 702 by the actuator piston spring 918, although relatively small, nonetheless reduces the range stress that the external plunger spring 146 must withstand. Ultimately, the actuator piston spring 918 may be a high force, low travel spring that provides the high force required specifically for low lift, potentially high speed valve actuation motions. This burden sharing by the actuator piston spring 918 and external plunger spring 146 can also relieve the need for the rocker arm biasing element 620 to provide a high preload, and the design of the rocker arm biasing element 620 can be This allows for a lower speed, higher lift portion of the main valve operating motion that occurs during deactivated operation to be concentrated, which is a less stringent design constraint.

FIG. 12 illustrates a partial cross-sectional view of valve actuation system 1200 according to the embodiment of FIG. 5 . In this system 600, the valve actuating motion source is a cam (not shown) operably coupled to the motion receiving end 1206 of the rocker arm 1204 via a push tube 1202 and a cam (not shown), as illustrated in FIG. 1 above. and an intervening LM-mechanism 1216 of the type described. As in the embodiment illustrated in FIGS. 6-11 , rocker arm 1204 rotates and reciprocates about a rocker shaft (not shown), thereby providing valve actuation motion provided by the valve actuation motion source. , through the motion transfer end 1208 of the rocker arm 1204, to the valve bridge 1210. Ultimately, valve bridge 1210 is operably connected to a pair of engine valves 1212 and 1214. As further shown, rocker arm 1204 includes an LM+ mechanism 1218 of a type substantially similar to that illustrated and described above with respect to FIG. 2 . In this case, hydraulic fluid is provided to the LM-mechanism 1216 through suitable passages formed in the ball joint 1220 and the rocker shaft and rocker arm 1204. Similarly, hydraulic fluid is provided to the LM+ mechanism 1218 through suitable passages formed in the rocker shaft and rocker arm 1204. However, in this embodiment, the check valve 732 of the previous embodiment is replaced by a control valve 1222 to establish the hydraulic lock necessary to maintain the actuator piston in the extended state. The embodiment of Figure 12 is further characterized by the arrangement of the LM+ mechanism 1218 interacting only with a single engine valve 1214 via an appropriate bridge pin 1224.

In this embodiment, the LM-mechanism 1216 locks relative to the pushrod 1202 such that the pushrod 1202 is biased into contact with the cam and the rocker arm is biased in the direction of the engine valves 1212, 1214. It contains a relatively strong spring to bias the outer plunger of the mechanism outward. In this implementation, the external plunger of the LM-mechanism 1216 is not restricted from movement during engine operation (in contrast to the engine assembly where imposing movement restrictions on the LM-mechanism 1216 facilitates assembly). ).

Considering the configuration of the LM+ mechanism 1218, particularly the inwardly sprung actuator piston, a gap is provided between the actuator piston and the bridge pin when the LM+ mechanism 1218 is in its default state. As a result, during this default state, the LM+ mechanism 1218 is not in series with the LM- mechanism 1216 along the motion load path, as described above with respect to FIG. 5. Furthermore, despite the presence of a gap during the default state, the actuator piston may not be fully extended considering the strength of the external plunger piston spring as explained above. In this case, the actuator piston is then unable to fully extend until the main motion valve event occurs, thereby creating a gap sufficient to allow full expansion between the actuator piston and bridge pin 1224. However, when in the extended (activated) state, the actuator piston will transmit not only the auxiliary valve actuation motion applied to it, but also the main valve actuation motion applied to it, to its corresponding engine valve 1214. . In this case, the LM+ mechanism 1218 is placed in series with the LM- mechanism 1216 during the activated state of the actuator piston as described above with respect to FIG. 5 .

FIG. 13 illustrates a partial cross-sectional view of valve actuation system 1300 according to the embodiment of FIG. 5 . In particular, the embodiment illustrated in FIG. 13 is substantially similar to the embodiment of FIG. 12 , except that the spherical joint 1220 is replaced by a sliding pin 1320 that is biased outward and has limited movement. same. In this case, the external plunger spring of the LM-mechanism 1216 is preferably designed with a low preload during zero or low valve lift (e.g. on the base circle) and is dependent on the main valve actuation motion during the deactivated mode of operation. It has a spring rate necessary to obtain a peak force to control the full range of motion of the rocker arm 1204.

On the other hand, the sliding pin spring 1322 used to bias the sliding pin 1320 outward is configured with a relatively high preload and short stroke (actuator piston spring 918 discussed above) (substantially similar to). Because the sliding piston 1320 is capable of sliding within the bore, the sliding piston 1320 is subject to the rocker arm ( To ensure continuous fluid communication between 1204) and LM-mechanism 1216, it includes an annular channel 1334 and a radial opening 1336 aligned therewith. Additionally, a stroke adjustment screw 1338 functions to limit movement of the sliding pin 1320 out of the bore towards the LM-mechanism 1216. As explained in relation to the travel limiting performance applied to the actuator piston 702 above, the stroke adjustment screw 1338 prevents the full force of the sliding pin spring 1322 from being applied to the LM-mechanism 1216. , otherwise it will overload and potentially hinder its operation. Lash provided to the locking element within the LM- mechanism 1216 by appropriately selecting a stroke provided by the stroke adjustment screw 1338, i.e., a stroke equal to the motion that must be lost by it during the default operating state of the LM+ mechanism. may be selected to ensure its proper operation, as explained above. In fact, the assembly of sliding pin 1320, sliding pin spring 1322 and stroke adjustment screw 1338 then forms part of the LM+ mechanism in this embodiment.

As described above, various specific combinations of outwardly sprung (expand) and inwardly sprung (retract) elements may be provided within the LM+ and LM- mechanisms, with movement limited as required. . More generally, in one implementation, an LM- mechanism (again, more specifically, an element or component thereof) may be biased toward an expanded position, and an LM+ mechanism (again, more specifically, an element or component thereof) may be biased toward a collapsed position. It can be biased by position. In this case, the extended position of the LM-mechanism may have limited movement. In another implementation of any given embodiment, the LM- mechanism may be biased to the extended position by a first force and the LM+ mechanism may also be biased to the extended position by a second force. In this case, it is preferable that the first deflection force is larger than the second deflection force. Additionally, once again, the extended position of the LM-mechanism may result in limited movement. In another implementation, the LM- mechanism may be biased toward the extended position, and the LM+ mechanism may also be biased toward the extended position. However, in this case, the extended position of the LM+ mechanism has limited movement. In this implementation, a possible benefit of limiting the movement of the LM+ mechanism is to allow zero load on the valvetrain while on the cam base circle, thereby reducing bushing wear.

As mentioned above in relation to FIG. 4 and as shown in relation to FIG. 15 where like reference numerals refer to similar elements in comparison to FIG. 4 , the LM-mechanism 410' is configured to actuate the valve actuation motion path 406. A system 1500 may be provided that is arranged closer to the valve actuating motion source 402 than to the LM-mechanism 408'. However, unlike the system 400' of Figure 5, the LM+ mechanism 408' shown in Figure 15 allows the LM+ mechanism 408' to control the main valve actuation motion transmitted by the LM- mechanism 410'. It is always in series with the LM- mechanism 410', regardless of the operating state (default or activated) of the LM+ mechanism 408', so that it always serves to transmit and is never removed from the valve actuating load path 406.

In particular, when the LM+ mechanism 408' is in its default operating state, the LM+ mechanism 408' loses any auxiliary valve actuation motion, but the valve actuation motion source 402 and the LM- mechanism 408 It is configured to transmit the main valve operating motion applied to itself by '). On the other hand, when the LM+ mechanism 408' is in the activated operating state, i.e., controlled to transmit any auxiliary valve actuation motion applied to it, the LM+ mechanism 408' is connected to the valve actuation source ( 402) and LM-mechanism 410'. The valve actuation system 1500 thus configured may be configured to operate in a positive power mode, deactivated mode, or auxiliary mode ( This facilitates the operation of the cylinder 405 (e.g., engine braking), and consequently of the internal combustion engine. That is, system 1500 may implement the method as illustrated with reference to FIG. 14 and described above. However, in this case, the provision of the LM- and LM+ mechanisms in block 1402 occurs in the pre-rocker valve train component and valve bridge, respectively, as explained in more detail below. .

Figures 16-18 illustrate a valve actuation system 1600 according to the embodiment of Figure 15. In this embodiment, the valve actuation system 1600 includes an LM- mechanism 1602 disposed within or on a prerocker arm valve train component and an LM+ mechanism 1604 disposed on the valve bridge. As used herein, a pre-rocker arm valve train component includes any valve train component disposed within the valve train between a source of valve actuation motion (e.g., a cam; not shown) and a rocker arm 1620. can do. For example, this may include devices known in the art such as pushrods, tappets, roller followers, etc. In the example illustrated in FIGS. 16 and 17 , the prerocker arm valve train component includes a pushrod 1610 which, in turn, establishes contact between the pushrod 1610 and a cam (not shown). It is operably connected to a roller follower 1612. In this embodiment, LM-mechanism 1602 is mounted on the upper end of pushrod 1610 such that LM-mechanism 1602 is operably connected to both pushrod 1610 and rocker arm 1620. do. Additionally in this example, rocker arm 1620 is mounted thereon for reciprocating movement on a rocker shaft (not shown). Ultimately, rocker arm 1620 is operably connected to valve bridge 1630 on which LM+ mechanism 1604 is deployed. Consistent with a conventional internal combustion engine, the valve bridge 1630 is connected to two or more engine valves 1642, 1644 (intake or exhaust valves) that are biased to the closed position by corresponding valve springs 1646, 1648. It works. 16 further illustrates a fixed reaction surface 1650 in contact with the upper end of the LM-mechanism 1602, as described in more detail below.

Referring now to Figures 17 and 18, additional details of the embodiment of Figure 16 are illustrated and described. As mentioned above, pushrod 1610 has an LM-mechanism 1602 mounted thereon. In this embodiment, the LM-mechanism 1602 has an interference fit between the inner diameter 1705 of the pushrod 1610 and a stud 1704 extending away from the base wall 1703 of the housing 1702. It includes a housing 1702 that is mounted on the push rod 1610 through a fit or screw connection. Alternatively, housing 1702 may be integrally formed as part of pushrod 1610 or pushrod 1610 may be incorporated into a receptacle formed on the exterior of base wall 1703 of housing 1702. It may also be inserted. A closed housing bore 1706 is formed in housing 1702 and includes an outer plunger 1708, an inner plunger 1712, an inner plunger spring retainer 1714, an inner plunger spring 1716, an outer plunger spring 1709, and In this embodiment it is configured to receive one or more locking elements 1718, illustrated as wedges. An external plunger spring 1709 disposed within the housing bore 1706 and between the base wall 1703 and the external plunger 1708 pushes the external plunger 1708 into the housing bore 1706 (as illustrated in FIG. 17 ). It deflects upward from within. The inner plunger 1712 is disposed within an inner bore 1710 formed in the outer plunger 1708. Internal plunger spring 1716, disposed between internal plunger 1712 and internal plunger spring retainer 1714 (which is attached to and closes the lower end of internal bore 1710), causes internal plunger 1712 to close internal bore 1710. ) is biased upward. The upward movement of the internal plunger 1712 is limited by a stop surface 1726 formed at the upper end of the internal bore 1710. The outer plunger 1708 includes an opening extending through a side wall of the outer plunger 1708 into which a wedge 1718 is disposed, the wedge 1718 having an annular outer rib formed at a surface defining the housing bore 1706. It is constructed to mesh with Seth (1720).

In the absence of hydraulic control applied to the internal plunger 1712 through the opening at the upper end of the internal bore 1710, i.e., in the default state of the LM-mechanism 1602 as illustrated in FIG. 17, the internal piston spring 1716 allows a wedge 1718 to extend out of the opening formed in the outer plunger 1708, thereby engaging the outer recess 1720 and holding the outer plunger 1708 in place relative to the housing 1702. Deflects the internal plunger 1712, effectively in the locked position. In this default state, any valve actuation motion (whether main or auxiliary motion) applied to push tube 1610 will result in the outer plunger 1708 being effectively locked in a position relative to housing 1702. Thanks to this, it is transmitted by the LM-mechanism 1602. However, provision of sufficiently pressurized hydraulic fluid to the top of the inner plunger 1712 causes the wedge 1718 to contract and separate from the outer recess 1720, thereby causing the outer plunger (1718) to compress against the housing 1720. effectively unlocks 1708 and allows inner plunger 1712 to allow outer plunger 1708 to slide freely within housing bore 1706, subject to the bias provided by outer plunger spring 1709. Make it slide downward. In this activated state, any valve actuating motion applied to housing 1702 by pushrod 1610 causes pushrod 1610 and housing 1702 to move while external plunger 1708 remains stationary. will cause it to reciprocate according to the applied operating motion. In this manner, and assuming that the movement of the external plunger 1708 within the housing bore 1706 is greater than the maximum extent of any applied valve actuation motion, such valve actuation motion will not be transmitted to the engine valves and the corresponding valve actuation motion will not be transmitted to the engine valves. The cylinder is effectively lost so that it becomes inactive.

In a further illustrated embodiment, the biasing spring 1722 is positioned between and with the fixed contact surface 1650 and the flange 1724 formed on the outer surface of the housing 1702 and extending radially away from it. placed in contact with each other. As shown, the fixed contact surface 1650, while still engaging the upper end of the biasing spring 1722, provides a passageway to the outer plunger 1708 through a lash adjustment screw disposed on the rocker arm 1620. 1730). The biasing spring 1722 manages the inertia of the pushrod 1610 and the LM-mechanism 1602 as they reciprocate according to the valve actuation motion applied to the pushrod 1610. is provided to ensure that the valve maintains contact with the source of actuating motion (in this example via roller follower 1612). The use of a fixed contact surface 1650 for this purpose ensures that the relatively large bias applied by the biasing spring 1722 is also applied (via the rocker arm 1620) to the LM+ mechanism 1604 and its This can prevent interference with movement. In contrast, the outer plunger spring 1709 is a relatively light spring sufficient to bias the outer plunger 1708 into contact with the rocker arm 1620/lash adjustment screw 1730 but, once again, the LM+ mechanism 1604. It is not strong enough to interfere with the movement of

As is known in the art, the rocker shaft (not shown) may have channels for supplying pressurized hydraulic fluid to hydraulic passages 1736 and 1738 formed in rocker arm 1620. As is further known in the art, such supply of hydraulic fluid may be controlled through the use of appropriate solenoids (not shown) under the supervision of controller 420. Hydraulic passages 1736 and 1738 route hydraulic fluid to each of the LM- mechanism 1602 and LM+ mechanisms 1604. By selectively controlling the flow of hydraulic fluid through each passage 1736, 1738, the respective default/activated states of the LM- and LM- mechanisms 1602, 1604 may likewise be controlled.

For this purpose, the rocker arm 1620 is equipped with a lash adjustment screw 1730, as known in the art, in which a first fluid passage 1734 is formed and terminates in a ball joint 1732. Ball joint 1732 is configured complementary to outer plunger 1708 such that fluid communication between first fluid passageway 1734 and inner bore 1710 is provided throughout all operations of valve actuation system 1600. It is formed to engage with the upper surface. First hydraulic passage 1736 is in fluid communication with first fluid passage 1734 such that hydraulic fluid may optionally be provided as a control input to LM-mechanism 1602 as described above.

Similarly, rocker arm 1620, in this example, has a ball joint 1742 with a second fluid passage 1740 formed therein and in communication with a second hydraulic passage 1738. The ball joint 1742 is attached to a swivel or e-foot 1744 with an opening 1746 formed therein to provide continuous fluid communication between the first fluid passageway 1740 and the LM+ mechanism 1604. are combined. Once again, this continuous fluid communication allows hydraulic fluid to be selectively provided as a control input to the LM+ mechanism 1604, as described above.

Additional details of the LM+ mechanism 1604 are further illustrated with respect to FIG. 18 . In particular, the LM+ mechanism 1604 includes a lost motion piston 1802 disposed in a closed centrally formed bore 1804 of the valve bridge 1630. Lost motion piston 1802 includes a piston opening 1803 that provides fluid communication between a first fluid passageway 1740/opening 1746 and an internal bore 1813 formed in lost motion piston 1802. The lost motion piston 1802 further includes a check valve assembly including a check disk (or ball) 1802, a check spring 1808, a check spring retainer 1810, and a retainer clip 1812 disposed within the bore 1813. Includes. The retainer clip 1812 allows the check spring 1808 to continuously bias the check disk 1806 into contact with the upper wall of the lost motion piston 1802, thereby causing sufficient pressure provided from the first fluid passageway 1740. A check spring retainer 1810 is maintained in a fixed position within the bore 1813 to seal the first fluid passage 1740 from the bore 1813 in the absence of hydraulic fluid. The lost motion piston 1802 is biased out of the bore 1804 and into contact with the swivel 1744 by a piston spring 1814 disposed within the bore 1804, thereby forming the lost motion piston 1802 and the swivel 1744. ), thereby ensuring continuous fluid communication.

As is known in the art, lost motion piston 1802 is configured to travel a distance (lost motion lash) at least as large as any auxiliary valve actuation motion applied to it by rocker arm 1620. Accordingly, when hydraulic fluid is not provided to the lost motion piston 1802 and its check valve assembly, the lost motion piston 1802 is coupled to the rocker arm 1620 by the external plunger spring 1709 through the external plunger 1708. Under the influence of the applied deflection it will retract into the bore 1804 and bottom out therein, and will remain bottomed out within the bore 1804 when valve actuation motion is applied to the lost motion piston 1802. . Since the amount of movement of the lost motion piston 1802 is at least as large as any auxiliary valve actuation motion applied to it, such auxiliary valve actuation motion will be lost in this situation, while larger valve actuation motions, such as the main event Valve actuation will be transmitted to valve bridge 1630 via lost motion piston 1802.

However, if sufficiently pressurized hydraulic fluid is provided to the lost motion piston 1802 through the check valve assembly, hydraulic fluid will flow past the check disk 1806 and into the bore 1804 beneath the lost motion piston 1802. As is known in the art, this will establish a confined volume of relatively incompressible hydraulic fluid behind the lost motion piston 1802, thereby causing the lost motion piston 1802 to expand out of the bore 1804. and will maintain its expanded state while the valve operating motion is applied to it. As a result, any valve actuation motion (both main and secondary valve actuation motion) applied to the lost motion piston 1802 will be transmitted to the valve bridge 1630.

As mentioned above, the embodiment illustrated in Figures 16-18 is based on the use of a pushrod as a pre-rocker arm valve train component configured to include an LM-mechanism. However, as further noted above, the prerocker arm valve train component may be implemented using other valve train components. For example, in one embodiment, the LM-mechanism, such as the locking mechanism described above, may be implemented in a cam follower, lifter or similar component. In this case, the hydraulic fluid required to control the locking mechanism can be provided through suitable passages formed in the pushrod or using other hydraulic fluid supply techniques known to those skilled in the art.

Claims (11)

a valve bridge operably connected to a cylinder, at least one engine valve and a rocker arm associated with the cylinder, and a pre-rocker arm valve train component operably connected to the rocker arm. A valve actuation system for use in an internal combustion engine comprising a valve actuation load path that:
a single cam configured to provide a main valve actuation motion and an auxiliary valve actuation motion to actuate the at least one engine valve through the valve actuation load path;
arranged in the pre-rocker arm valve train component, and configured to, in a first default operating state, transmit at least the main valve actuating motion, and in a first activated state, lose the main valve actuating motion and the auxiliary valve actuating motion. a lost motion subtracting mechanism configured to; and
a lost motion adding mechanism arranged in the valve bridge, configured to, in a second default operating state, lose the auxiliary valve actuating motion and, in a second activated state, to transmit the auxiliary valve actuating motion - the lost A valve actuating system for use in an internal combustion engine, comprising: a motion adding mechanism arranged in series with the lost motion reducing mechanism in the valve actuating load path. According to paragraph 1,
Using the lost motion reduction mechanism and the lost motion addition mechanism, the internal combustion engine:
a positive power mode in which the lost motion reduction mechanism is in the first default operating state and the lost motion adding mechanism is in the second default operating state; or
a deactivated mode in which the lost motion reduction mechanism is in the first activated operating state and the lost motion adding mechanism is in the second default operating state; or
A secondary mode in which the lost motion reduction mechanism is in the first default operating state and the lost motion adding mechanism is in the second activated operating state.
A valve actuation system for use in an internal combustion engine, further comprising an engine controller configured to operate in. According to paragraph 1,
The auxiliary valve actuation motion may be an early exhaust valve opening valve actuation motion, a late intake valve closing valve actuation motion, or an engine braking valve actuation. A valve actuating system for use in an internal combustion engine, which is at least one of: According to paragraph 1,
A valve actuation system for use in an internal combustion engine, wherein the lost motion reduction mechanism is a hydraulically controlled mechanical locking mechanism. According to paragraph 1,
A valve actuating system for use in an internal combustion engine, wherein the lost motion adding mechanism is a hydraulically controlled actuator. According to clause 5,
wherein the lost motion addition mechanism further comprises a hydraulically controlled check valve providing hydraulic fluid to the hydraulically controlled actuator. According to paragraph 1,
A valve actuation system for use in an internal combustion engine, further comprising a first spring configured to bias the free rocker arm component toward the single cam. In clause 7,
A valve actuation system for use in an internal combustion engine, wherein the free rocker arm component includes a pushrod and the first spring is operably connected to the pushrod. According to paragraph 1,
A valve actuation system for use in an internal combustion engine, further comprising a second spring configured to bias the rocker arm toward the single cam. In clause 7,
The valve actuating system for use in an internal combustion engine, wherein the second spring is disposed in the lost motion addition mechanism. a valve actuation load path comprising a cylinder and at least one engine valve associated with the cylinder, the valve bridge operably connected to a rocker arm and a pre-rocker arm valve train component operably connected to the rocker arm. A method of operating an internal combustion engine further comprising a single cam configured to provide a main valve actuating motion and an auxiliary valve actuating motion for actuating the at least one engine valve, comprising:
arranged in the pre-rocker arm valve train component, and configured to, in a first default operating state, transmit at least the main valve actuating motion, and in a first activated state, lose the main valve actuating motion and the auxiliary valve actuating motion. providing a lost motion reduction mechanism configured to:
a lost motion adding mechanism arranged in the valve bridge, configured to, in a second default operating state, lose the auxiliary valve actuating motion and, in a second activated state, to transmit the auxiliary valve actuating motion - the lost providing a motion adding mechanism arranged in series with the lost motion reducing mechanism in the valve actuating load path; and
The above internal combustion engine:
a positive power mode in which the lost motion reduction mechanism is in the first default operating state and the lost motion adding mechanism is in the second default operating state; or
a deactivated mode in which the lost motion reduction mechanism is in the first activated operating state and the lost motion adding mechanism is in the second default operating state; or
A secondary mode in which the lost motion reduction mechanism is in the first default operating state and the lost motion adding mechanism is in the second activated operating state.
A method of operating an internal combustion engine, comprising the step of operating in .

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