Discrete lost motion device

Abstract

A discrete lost motion device for use in a valve train of an internal combustion engine includes a housing having a housing bore extending longitudinally into the housing and a second end having a housing contact surface configured to engage a corresponding contact surface of a first valve train component. A plunger slidably disposed in the housing bore is controllable between a first state in which the plunger rigidly extends out of the housing bore and a second state in which the plunger is permitted to reciprocate within the housing bore, the plunger further comprising an end having a plunger contact surface, the plunger contact surface is configured to engage a corresponding contact surface of a second valve mechanism component. The housing contact surface and the plunger contact surface are configured to support the discrete lost motion device between the first valve train component and the second valve train component.

Description

Background Art

[0001] Valve actuation in an internal combustion engine is necessary for engine operation. Generally, the valve actuation force for opening an engine valve (i.e., an intake valve, an exhaust valve, or an auxiliary engine valve) is transmitted by a valve train, where such valve actuation force can be provided by a primary motion source and / or an auxiliary motion source. As used herein, the descriptor "primary" refers to the so-called primary event engine valve motion, i.e., the valve motion used during positive power generation, where fuel is burned in an engine cylinder to provide a net output of engine power; however, the descriptor "auxiliary" refers to other engine valve motions used for purposes alternative to positive power generation (e.g., compression release braking, exhaust braking, cylinder deactivation, cylinder cut-off, brake gas recirculation (BGR), etc.) or as a supplement to positive power generation (e.g., internal exhaust gas recirculation (IEGR), variable valve actuation (VVA), early exhaust valve opening (EEVO), late intake valve closing (LIVC), swirl control, etc.).

[0002] In many internal combustion engines, the primary motion source and / or the auxiliary motion source can be provided by a cam with a fixed profile, and more specifically by one or more fixed lobes or protrusions (which can be an integral part of each cam in the cam). If the intake valve and / or exhaust valve timing and lift can be changed, benefits such as improved performance, better fuel economy, reduced emissions, and better vehicle drivability can be obtained. However, the use of a fixed profile cam may make it difficult to adjust the timing and / or amount of engine valve lift to optimize them for various engine operating conditions.

[0003] Given a fixed cam profile, one method of adjusting valve timing and lift is to provide a "lash" or variable length device in the valvetrain linkage between a given engine valve and its corresponding cam. Lash is a term applied to a class of technical solutions for varying the valve actuation motion defined by a cam profile having variable length mechanical, hydraulic, or other linkage components. In a lash system, the cam lobe can provide the "maximum" motion (longest dwell and maximum lift) required over the full range of engine operating conditions, including positive power generation operation and / or auxiliary operation as required in some cases. The variable length system can then be included in the valvetrain linkage between the valve to be opened and the cam providing the maximum motion to reduce or lose some or all of the motion imparted to the valve by the cam. Typically, such a lash device is capable of being controlled between a "locked" or motion transmitting state and an "unlocked" or motion absorbing state. During the locked state, the lash device remains in a substantially rigid configuration (allowing clearance adjustment) such that the valve actuation motion applied to it is transmitted to the corresponding engine valve. On the other hand, during the unlocked state, the lash device is allowed to absorb or avoid (i.e., "lose") any valve actuation motion applied to it, thereby preventing such valve actuation motion from being transmitted to the corresponding engine valve.

[0004] Figure 1 An embodiment of a conventional valve actuation system 100 including a lash member 130 is schematically shown. As shown, the valve actuation system 100 includes a valve actuation motion source 102 which, in this example, serves as the sole source of valve actuation motion (i.e., valve opening motion and valve closing motion) to one or more engine valves 104 via a valve actuation load path 106. The one or more engine valves 104 are associated with a cylinder 105 of an internal combustion engine. As is known in the art, each cylinder 105 typically has at least one valve actuation motion source 102 uniquely corresponding to it for actuating the corresponding engine valve 104. Additionally, while only a single cylinder 105 is shown in Figure 1 it should be understood that an internal combustion engine can include and often does include more than one cylinder, and the valve actuation system described herein is applicable to any number of cylinders of a given internal combustion engine.

[0005] The valve actuation motion source 102 can include any combination of known elements capable of providing valve actuation motion, such as a cam. The valve actuation motion source 110 can be dedicated to providing exhaust motion, intake motion, auxiliary motion, a combination of exhaust and intake motion, or a further combination of such a combination with auxiliary motion.

[0006] As shown, the valve actuation load path 106 can include one or more valve train components (in the example shown, a first valve train component 108 and a second valve train component 110), which are deployed between a valve actuation motion source 102 and at least one engine valve 104 and are configured to transfer the motion provided by the valve actuation motion source 102 to the at least one engine valve 104, such as a tappet, a push rod, a rocker arm, a valve bridge, an automatic lash adjuster, etc. Although Figure 1 two valve train components 108, 110 are shown, it should be understood that more or fewer valve train components may be used. Further, in this example, the valve actuation load path 106 includes a lost motion component 130 housed within the second valve train component 110. That is, although the lost motion component 130 may contact other components in the valve train 106, the lost motion component is fully supported within the valve train 106 due to being housed within the second valve train component 110. As used herein, the term "supported" means being held within the valve train or being in functional communication with the valve train. For example, the second valve train component 110 may be implemented by a rocker arm or a valve bridge that has a hole formed therein, and the components forming the lost motion component 130 are deployed within the hole such that the support for such a lost motion component 130 is provided only or primarily by the rocker arm.

[0007] As Figure 1 further shown, an engine controller 120 may be provided and is operably connected to the lost motion component 130. The engine controller 120 can include any electronic, mechanical, hydraulic, electro-hydraulic, or other type of control device for controlling the operation of the lost motion mechanism 130, i.e., switching between its respective locked and unlocked states as described above. For example, the engine controller 120 may be implemented by a microprocessor and a corresponding memory storing executable instructions for implementing the desired control functions, including those described below that are known in the art. It should be understood that other functionally equivalent specific implementations of the engine controller 130 (e.g., a suitably programmed application-specific integrated circuit (ASIC), etc.) may be equivalently employed. Further, the engine controller 120 may include peripherals that are intermediate the engine controller 120 and the lost motion device 130, which allow the engine controller 120 to implement control over the operating state of the lost motion device 130. For example, in the case where the lost motion device 130 is a hydraulically controlled mechanism (i.e., responsive to the absence or application of hydraulic fluid to an input), such peripherals may include suitable solenoids known in the art.

[0008] Figure 2Another embodiment of a conventional valve actuation system 100’ including a pneumatic member 230 is schematically shown, where, compared with Figure 1 the same reference numerals represent the same elements. In this second embodiment, the pneumatic member 230 is not received (and thus supported) within one of the valve mechanism members 108, 110, but is received within a fixed member 232, such as a cylinder head or engine block, while still contacting the second valve mechanism member 110. For example, where the second valve mechanism member 110 is an end pivoting rocker arm or finger follower, the pneumatic member 230 may be implemented by a collapsible pivot known in the prior art.

[0009] Cost, packaging, and size are often factors that determine the desirability of an engine valve actuation system. Typically, in cases where it is desired to incorporate one or more pneumatic members into the valve mechanism, the ability to include valve mechanism members that support such pneumatic members may be limited by a variety of factors, for example, lack of space due to their large size and / or high cost. Thus, providing pneumatic members that overcome these limitations would represent a welcome technological advance. SUMMARY OF THE INVENTION

[0010] The present disclosure describes various embodiments of a discrete pneumatic device for use in a valve mechanism of an internal combustion engine, the valve mechanism having at least a first valve mechanism member and a second valve mechanism member, and where the discrete pneumatic device includes a housing having a housing bore extending longitudinally into the housing from a first end of the housing, the housing further including a second end having a housing contact surface configured to engage a corresponding contact surface of the first valve mechanism member. The discrete pneumatic device further includes a plunger slidably disposed within the housing bore through the first end of the housing and capable of being controlled between a first state in which the plunger rigidly extends out of the housing bore and a second state in which the plunger is permitted to reciprocate within the housing bore, the plunger further including an end having a plunger contact surface configured to engage a corresponding contact surface of the second valve mechanism member. In the disclosed embodiments, the housing contact surface and the plunger contact surface are configured to support the discrete pneumatic device between the first valve mechanism member and the second valve mechanism member.

[0011] In one embodiment, the housing contact surface and the plunger contact surface are configured to permit the discrete pneumatic device to rotate relative to the first valve mechanism member or the second valve mechanism member or both. For example, either the housing contact surface or the plunger contact surface may include a convex contact surface or a concave contact surface, or more specifically, either the housing contact surface or the plunger contact surface may include a spherical contact surface.

[0012] In one embodiment, the second end of the housing or the end of the plunger includes a hydraulic passage configured to receive hydraulic fluid to control the plunger between a first state and a second state of the plunger. The discrete air actuated component may include a hydraulically controlled locking mechanism configured to lock the plunger relative to the housing in the first state and unlock the plunger relative to the housing in the second state, wherein the hydraulic passage is in fluid communication with the hydraulically controlled locking mechanism. In a specific implementation, the hydraulically controlled locking mechanism defaults to a locked state, and applying hydraulic fluid via the hydraulic passage results in an unlocked state of the hydraulically controlled locking mechanism; however, in another specific implementation, the hydraulically controlled locking mechanism defaults to an unlocked state, and applying hydraulic fluid via the hydraulic passage results in a locked state of the hydraulically controlled locking mechanism.

[0013] In addition, the hydraulically controlled locking mechanism may include an inner plunger slidably disposed in a longitudinal bore formed in the plunger and a radially extending locking element disposed in a radial opening formed in the plunger, and wherein the housing bore includes an annular recess engaged by the locking element when the locking element extends out of the radial opening. The longitudinal length of the annular recess may be greater than the thickness of the locking element, and the longitudinal length of the annular recess is at least large enough to accommodate the maximum spacing between the first valve mechanism component and the second valve mechanism component when the element extends out of the radial opening and engages the annular recess.

[0014] Alternatively, the discrete air actuated device may include a check valve in fluid communication with the hydraulic passage and configured to establish a certain amount of locking hydraulic fluid between the housing and the plunger. In this embodiment, the check valve may be deployed in a control valve upstream of the discrete air actuated device or may be deployed within the discrete air actuated device. Additionally, a biasing pin may be arranged to open the check valve when hydraulic fluid is not supplied via the hydraulic passage and allow the check valve to close when hydraulic fluid is supplied via the hydraulic passage.

[0015] In another embodiment, the discrete air actuated device may include a plunger spring that biases the plunger out of the plunger bore. In this case, the plunger spring may be disposed within the housing bore or outside the housing.

[0016] In another embodiment, the stroke of the plunger out of the housing bore is limited.

[0017] In yet another embodiment, the housing contact surface or the plunger contact surface may be configured to attach to a corresponding one of the first valve mechanism component or the second valve mechanism component. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of specific embodiments in conjunction with the accompanying drawings, in which:

[0019] Figure 1 and Figure 2 schematically shows a valve actuation system according to the prior art;

[0020] Figure 3 schematically shows a valve actuation system according to the present disclosure, the valve actuation system including a free floating member;

[0021] Figures 4 to 7 shows a first embodiment of the free floating member according to the present disclosure;

[0022] Figure 8 、 Figure 9 and Figure 9A shows a second embodiment of the free floating member according to the present disclosure;

[0023] Figure 10 and Figure 10A shows a third embodiment of the free floating member according to the present disclosure; and

[0024] Figures 11 to 16 shows various alternative embodiments for providing a travel limit within the free floating member according to the present disclosure. DETAILED DESCRIPTION

[0025] Figure 3 schematically shows an embodiment of a valve actuation system 300 according to the present disclosure, the valve actuation system including a discrete free floating member 330, wherein compared with Figure 1 and Figure 2 the same reference numerals represent the same elements. As used herein, "discrete" has its ordinary meaning of being a separate entity or part. Thus, in this second embodiment, the discrete free floating member 330 is not housed or supported within one of the valve train components 108, 110 as in the case of Figure 1 or housed or supported within a stationary member 232 as in the case of Figure 2 , but is formed as a discrete member that is supported within the valve train 106 by one or more adjacent valve train components 108, 110, as described in further detail below. Generally, the support of the discrete free floating member 330 is provided by one or more support joints. As used herein, a support joint is a combination of two elements that (i) are joined in the sense of being in close association or relationship with each other (from being separable in contact with each other to including being inseparably connected to each other), and (ii) are configured to carry or hold the discrete free floating member within the valve train. Additionally, the support joint can provide a degree of freedom of rotation for the discrete free floating member 330 relative to one or more adjacent valve train components.

[0026] In Figure 3In the example shown, such support joints 340, 341 are schematically shown as including a combination of contact surfaces 330a, 330b disposed on the discrete pneumatic member 330 and corresponding contact surfaces 108a, 110a disposed on the adjacent valve mechanism members 108, 110. As described in more detail below, the contact surfaces 330a, 330b of the discrete pneumatic member 330 and the corresponding contact surfaces 108a, 110a of the valve mechanism members 108, 110 are complementarily configured to facilitate the support of the discrete pneumatic member 330 by the valve mechanism members 108, 110 and to facilitate the operation of the discrete pneumatic member 330 despite the movement of the valve mechanism members 108, 110. Accordingly, it should be understood that the various complementary contact surfaces described herein are examples of support joints or portions thereof that can be used to implement the discrete pneumatic member 330 (and its various specific embodiments described below).

[0027] Accordingly, the valve actuation system 300 is considered to include the discrete pneumatic member 330 and the adjacent valve mechanism members 108, 110 that support the discrete pneumatic member 330.

[0028] As Figure 3 Further shown, the control of the discrete pneumatic member 330 by the engine controller 120 is provided via a path through at least one of the adjacent valve mechanism members 108, 110. For example, in the various embodiments described below, such control is provided by using hydraulic fluid supplied under the control of the engine controller 120. However, as will be understood by those skilled in the art, other types of control schemes can equally be used for this purpose. In the case where fluid is supplied under the control of the engine controller 120, the present disclosure features that such fluid supply passages pass through at least one of the contact surfaces 108a, 110a, 330a, 330b, various examples of which are further shown and described below.

[0029] Figures 4 to 7 A first embodiment of the discrete pneumatic member 400 is shown, which can be used as Figure 3 the discrete pneumatic member 330 shown in the embodiment shown. In particular, Figure 4 and Figure 5A perspective view of a discrete free floating component 400 is shown, which includes a housing 402 having a plunger 410 disposed therein through a first end 404 of the housing 402. As shown, both the housing 402 and the plunger 410 are centered about a longitudinal axis 420 of the discrete free floating component 400. As described above, the discrete free floating component 400 is configured to exist as an independent structure relative to other valve train components, but is not surrounded or fully supported by a single valve train component or a fixed structure, but still contacts other valve train components to be supported within the entire valve train. As Figure 7 best shown, the plunger 410 is slidably disposed in a housing bore 702 formed in the housing 402.

[0030] In addition, the housing 402 has a housing contact surface 408 formed at a second end 406 of the housing 402, and the plunger 410 has a plunger contact surface 414 formed at a first end 412 of the plunger 410 extending out of the housing 402. In a particular embodiment, each of the housing contact surface 408 and the plunger contact surface 414 (such as Figure 3 the contact surfaces 330a, 330b shown) is configured to cooperate with complementary contact surfaces (such as Figure 3 the contact surfaces 108a, 110a shown) formed in adjacent valve train components. In the example shown, both the housing contact surface 408 and the plunger contact surface 414 are formed as convex surfaces configured to engage corresponding and complementary concave surfaces as described below, but it should be understood that the housing contact surface 408 and the plunger contact surface 414 can also be formed as concave surfaces configured to engage corresponding and complementary convex surfaces as also described below. In yet another alternative, the housing contact surface 408 and the plunger contact surface 414 can be formed as corresponding concave and convex surfaces, and vice versa. In any case, in one embodiment, the convex and concave surfaces can be spherical contact surfaces. In addition, as Figure 4 best shown, the illustrated embodiment also includes a hydraulic passage 416 formed in the first end 412 of the plunger 410, and more specifically, an opening of the hydraulic passage 416 is formed within the plunger contact surface 414. Although the hydraulic passage 416 is shown as being formed within the plunger 410, it should be understood that such a passage can alternatively be formed in the second end 406 of the housing 402, and more specifically, an opening of the hydraulic passage 416 is formed within the housing contact surface 408.

[0031] Now referring to Figure 6, the discrete floating component 400 is shown in contact (shown in cross-section) with adjacent valve train components 602, 604. In this embodiment, the convex housing contact surface 408 and the plunger contact surface 414 are shown engaging corresponding concave contact surfaces 606, 608 formed in the adjacent valve train components 602, 604, respectively, such as Figure 3 the contact surfaces 108a, 110a shown in

[0032] As Figure 6 further shown, the first valve train component 602 is configured with a first hydraulic passage 610 that is registered with a hydraulic passage 416 formed in the plunger 410. In one embodiment, the diameters of the hydraulic passages 416, 610 are each large enough to ensure fluid communication between the hydraulic passages 416, 610, regardless of the rotational movement of the first valve train component 602 relative to the plunger 410. As referenced Figure 7 above, supplying or removing pressurized hydraulic fluid (e.g., from an engine oil pump) through the hydraulic passages 416, 610 can provide control of the locked and unlocked states of the operation of the discrete floating component 400.

[0033] Now referring to Figure 7 , the discrete floating component 400 is depicted in cross-section to better show the hydraulically controlled locking mechanism 704 deployed between the housing 402 and the plunger 410. A plunger spring 716 is provided to bias the plunger 410 out of the housing 402. Figure 7 The locking mechanism 704 shown is generally of the type described in U.S. Patent No. 9,790,824, the teachings of which are incorporated herein by reference and repeated in the relevant section below.

[0034] As Figure 7As shown, the locking mechanism 704 includes a plunger 410 disposed within a housing bore 702 formed in the first end 404 of the housing 402 and extending along a longitudinal axis 420. An inner plunger 710 is slidably disposed within a longitudinal bore 714 formed in the plunger 410. Locking elements in the form of wedges 706 are provided and are configured to engage an annular outer recess 708 formed in the surface defining the housing bore 702. The illustrated embodiment is a locking mechanism 704 in a normal locked state, i.e., in the absence of applying hydraulic control via (in this case) a hydraulic passage 416 to the inner plunger 710, an inner plunger spring 712 biases the inner plunger 710 into position such that the wedges 706 contact a full diameter portion of the inner plunger 710 and thus radially extend out of an opening formed in the plunger 410 to engage the outer recess 708 and effectively lock the plunger 410 in place relative to the housing 402.

[0035] In this locked state, any valve actuation movement applied to either end of the discrete floating member 400 (whether primary or secondary movement and affected by the clearance provided by the discrete floating member) is thereby transmitted. It should be noted that although in the locked state as Figure 7 shown, the longitudinal length of the outer recess 708 is greater than the thickness of the wedges 706 such that a small amount of movement is still permitted between the plunger 410 and the housing 403, as described in further detail below. As Figure 7 shown, for example, in the case where valve actuation movement has been applied to the discrete floating member 400 to overcome any outward biasing applied to the plunger 410 by the plunger spring 716, this additional space has been occupied.

[0036] Alternatively, when the discrete floating member 400 is unloaded while still in the locked state (e.g., during the cam base circle), the biasing applied by the plunger spring 716 causes the plunger 410 to translate within its bore 702 to the extent permitted by the longitudinal length of the outer recess 708, i.e., translate to the Figure 7 left side as shown until the wedges 706 abut the leftmost surface of the outer recess 708. In this way, the plunger spring 716 ensures that the housing contact surface 408 and the plunger contact surface 414 continue to be biased into contact with the corresponding contact surfaces 608, 606 of the adjacent valve train components 602, 604 (as Figure 6 shown) as long as this longitudinal length is greater than any clearance within the valve train in the unloaded state.

[0037] This biasing force applied by the plunger spring 716 can be selected to additionally ensure that the adjacent valve train components 602, 604 (or such additional upstream or downstream valve train components in the system, not shown) are biased into continuous contact with the respective end points of the valve train (i.e., the valve actuation motion source and the engine valve). Further, since the outward stroke of the plunger 410 from within its bore 702 is limited by the longitudinal length of the outer recess 708 (when in the locked state), the biasing force applied by the plunger spring 716 to the adjacent valve train components 602, 604 (and again, any additional upstream or downstream valve train components in the system) will not impose an excessive biasing force on the normal operation of any automatically adjustable flexible components (such as hydraulic lash adjusters, etc.) within the valve train. As described below with respect to further embodiments, for this purpose, other specific implementations providing such a stroke limitation of the plunger 410 relative to the housing 402 can be employed even during the unlocked state of the discrete lash component 400.

[0038] Referring again to Figure 7 , hydraulic fluid that is sufficiently pressurized to overcome the biasing force of the internal plunger spring 712 is provided to the top of the internal plunger 710 (the leftmost surface as shown Figure 7 ) via the hydraulic passage 416, causing the internal plunger 710 to translate within the bore 714 such that the wedge 706 is aligned with the reduced diameter portion of the internal plunger 710 and is allowed to retract from and disengage from the outer recess 708, thereby effectively unlocking the plunger 410 relative to the housing 402 and allowing the plunger 410 to freely slide within its bore 702 due to the biasing force provided by the plunger spring 716 in this case. In this unlocked state, any valve actuation motion applied to the discrete lash component 400 will cause the plunger 410 to reciprocate within its bore 702. In this manner, and assuming that the stroke of the plunger 410 into its bore 702 is greater than the maximum extent of any applied valve actuation motion (i.e., the plunger 410 cannot reach the lowest point within its bore 702), such valve actuation motion will not be transmitted by the discrete lash component 400 and will effectively be lost.

[0039] Figure 8 , Figure 9 and Figure 9A show a second embodiment of the discrete lash component 800, which can be used as Figure 3 the discrete lash component 330 shown in the embodiment shown in Figure 7 . As shown, this embodiment similarly includes a housing 802 and a plunger 911 disposed along a longitudinal axis 820. However, in this case, Figure 9As best shown, the plunger spring 830 is deployed between a flange 930 formed on or attached to the outer surface of the plunger 911 and a shoulder 932 formed in the housing 802, as shown. In the illustrated embodiment, the flange 930 is fixed to the plunger 911 via an annular notch 931 formed in the outer surface of the plunger 911. As Figure 9 Further shown, the discrete idle member 800 also includes a locking mechanism 904, which includes an inner plunger 910, a wedge 906, and an annular channel 908, and the locking mechanism operates in the same manner as the corresponding components described above under the control of hydraulic fluid supplied by a hydraulic channel 916 formed in the plunger 911. Still further, in this embodiment, the housing 802 is not formed as a single-piece component, but has an end cap 940 firmly attached to the housing 802, which is substantially implemented as a tube or cylinder in this embodiment, and the second end of the tube or cylinder is closed by the end cap 940. In this embodiment, a housing contact surface 808 is formed in the end cap 940. Figure 7

[0040] Figure 9 Also shown are adjacent valve mechanism components 920, 924, which have corresponding contact surfaces 922, 926 that are configured to engage corresponding housing contact surfaces 808 and plunger contact surfaces 814. However, in this case, while the housing contact surface 808 is formed as a convex surface (consistent with the Figures 4 to 7 embodiment), which is configured to cooperate with the corresponding concave contact surface 922 of the adjacent valve mechanism component 920, the plunger contact surface 814 is formed as a concave surface, which is configured to cooperate with the corresponding convex surface 926 of the adjacent valve mechanism component 924. By contrarily configuring the housing contact surface 808 and the plunger contact surface 814 in this way, the possibility of incorrectly installing the discrete idle member 800 (i.e., being inverted relative to the Figure 9 shown orientation) can be effectively avoided.

[0041] Figure 9A An example of a discrete idle member 800’ similar to the Figure 9 shown embodiment is shown, but it is in a normal unlocking operation. Elements having the same reference numerals in Figure 9 and Figure 9A are substantially similar in structure and function, while reference numerals including an apostrophe (’) in Figure 9A refer to elements whose structure and / or function are different from the corresponding counterparts shown in Figure 9 , as described below. In Figure 9A ​In the illustrated embodiment, the free moving member 800’ again includes a housing 802’ having a longitudinal bore formed therein and a plunger 911’ slidably disposed in the bore. Again, an inner plunger 910’ is disposed in the bore formed in the plunger 911’ and is biased out of the bore by an inner plunger spring disposed between the inner plunger 910’ and a plunger cap 950 that is threadedly (in this case) fixed to the plunger 911’.

[0042] However, in this case, the structure of the inner plunger 910’ is substantially opposite to that of the inner plunger 910 Figure 9 shown such that in the absence of hydraulic control being applied to the inner plunger 910’, the inner plunger spring biases the inner plunger 910’ into position such that the wedge 906 does not radially extend out of the opening formed in the plunger 911’ and thus does not engage the outer annular recess 908’, effectively unlocking the plunger 911’ relative to the housing 802’ and allowing the plunger 911’ to freely slide within its bore due to the biasing provided by the plunger spring 930. In this unlocked state, any valve actuation movement applied to the free moving member 800’ will cause the plunger 911’ to reciprocate within its bore. In the illustrated embodiment, the plunger 911’ is configured such that the travel of the plunger 911’ within its bore allows the plunger 911’ to reach a “bottom most point”, i.e., in this case, contact between the plunger cap 950 and the closed end of the bore. In this way, the free moving member 800’ is able to prevent overextension of any hydraulic lash adjuster disposed in the same valve mechanism as the free moving member 800’. Additionally, this travel limitation of the plunger 911’ allows for the application of a “fail-safe” auxiliary valve actuation movement, such as a high lift brake gas recirculation (BGR) movement, in the event of a locking mechanism failure.

[0043] On the other hand, providing the input receiving end of the inner plunger 910’ (such as the bottom most surface Figure 9A shown) with hydraulic fluid that is sufficiently pressurized to overcome the biasing of the inner piston spring causes the inner plunger 910’ to translate within the bore such that the wedge 906 is forced to radially extend out of the opening formed in the plunger 911’ and engage the outer recess 908’, effectively locking the plunger 911’ relative to the housing 802’. In this locked state, any valve actuation movement applied to the free moving member 800’ will cause the plunger 911’ to engage the housing 802’, thereby transmitting such valve actuation movement.

[0044] Figure 9AAnother feature of the housing 802’ shown in FIG. is that the annular outer recess 908’ has a longitudinal length such that even when the floating member 800’ is in its locked / motion transfer state, the plunger 911’ is allowed to slide within its bore. This configuration of the outer recess 908’ accommodates the spacing between the valve train components adjacent to the discrete floating member 800’, which otherwise might allow the discrete floating member 800’ to lose contact with one or both of its adjacent valve train components and thus potentially move out of the valve train. For example, it is foreseeable that in some valve actuation systems, due to valve actuation motion generated outside the valve train where the discrete floating member 800’ is located, the valve train components on the output side of the discrete floating member 800’ can translate away from the discrete floating member 800’ (as well as the valve train components on the input side of the discrete floating member 800’). In such a case, the ability of the discrete floating member 800’ to expand to the maximum possible spacing between adjacent valve train components without losing contact with the adjacent valve train components allows the associated contact surfaces (such as 108a, 110, 330a, 330b) to continue to support the discrete floating member 800’ within the valve train.

[0045] Figure 10 A third embodiment of a discrete floating member 1000 is shown, which can be used as Figure 3 the discrete floating member 330 shown in the embodiment shown. In Figures 4 to 9 and Figure 9A the embodiments shown, mechanical-based locking mechanisms 704, 904 are provided to effect the locked / unlocked states of the floating mechanisms 400, 800. Different from these embodiments, the floating mechanism 1000 is fully hydraulic in its specific implementation. In particular, the discrete floating member 1000 also includes a housing 1002 and a plunger 1004 that is disposed within a longitudinally extending bore 1005 formed in the housing 1002. In this specific implementation, a spring 1006 is provided to bias the plunger 1004 out of the bore 1005 and into continuous contact with an adjacent valve train component (not shown). However, it should be understood that the spring 1006 can also be configured to ensure biasing the plunger 1004 into the bore 1005. Additionally, although shown as being disposed within the housing 1002, the spring 1006 can equally be deployed on the exterior of the housing 1002.

[0046] In any case, a hydraulic passage 1008 is provided in a housing 1008 so as to provide fluid communication between a hole 1005 and a hydraulic supply source 1012 via an intermediate control valve 1010 of a type known in the art. When hydraulic fluid is supplied to the control valve 1010, the hydraulic fluid is allowed to flow into the hole 1005 until the pressures on either side of a check valve (not shown) provided in the control valve 1010 are equal. At this time, the control valve 1010 checks the fluid provided in the hole 1005 so as to establish a locked amount of fluid within the hole 1005 such that the plunger 1004 is rigidly held in its extended position extending out of the hole 1005, i.e., the idle mechanism 1000 is in a locked state. Conversely, when the fluid pressure from the fluid source 1012 to the control valve is removed, the control valve 1010 operates to allow the locked amount of fluid to be discharged from the hole 1005, which in turn allows the plunger 1004 to reciprocate within the hole 1005, i.e., the idle mechanism 1000 is in an unlocked state.

[0047] Figure 10A An alternative embodiment of the third embodiment is shown, in which a control valve 1010' is provided within a housing 1002' of a discrete idle component 1000', opposite to that shown Figure 10 externally. Similarly, elements having the same reference numerals in Figure 10 and Figure 10A are substantially similar in structure and function, while reference numerals including an apostrophe (') in Figure 10A refer to elements that are characterized by having different structures and / or functions relative to the corresponding counterparts shown in Figure 10 as described below.

[0048] In this embodiment, the discrete idle component 1000' includes a housing 1002' having a plunger hole 1005', in which a plunger 1004' is slidably provided. Although not shown in Figure 10A , a suitable spring (not shown) may be used to appropriately bias the plunger 1004' into or out of the plunger hole 1002'. The housing 1002' further includes a piston hole 1022, which is formed opposite to the plunger hole 1005' and is in fluid communication with the plunger hole 1005' via a connecting passage 1040. A piston 1020 is slidably provided in the piston hole 1022 and is biased by a piston spring 1030 towards the connecting passage 1040 and the plunger hole 1005'. It should be noted that contact surfaces 1050, 1052 (substantially similar to those discussed above) are respectively provided on an input cover 1014 and the plunger 1004' (in this case, as corresponding concave and convex surfaces).

[0049] The control valve assembly 1010’ includes a check ball 1024 and a check ball guide 1026, which is fixedly disposed between the connection passage 1040 and the plunger hole 1005’. A check ball spring 1028 is disposed between the check ball guide 1026 and the check ball 1024 to bias the check ball 1024 into a seat formed at one end of the connection passage 1040, thereby tending to close the fluid communication between the connection passage 1040 and the plunger hole 1005’. However, the piston 1020 also includes a pin 1032 that extends away from the main body portion of the piston, through the connection passage 1040 and toward the check ball 1024. Under the biasing of the piston spring 1030, which is stronger than the biasing force applied by the check ball spring 1028 to the check ball 1024 and without any hydraulic fluid applied to the discrete pilot component 1000’ (described below), the pin 1032 will move the check ball 1024 away from its position at the end of the connection passage 1040, thereby maintaining the fluid communication between the connection passage 1040 and the plunger hole 1005’.

[0050] As Figure 10A As further shown, the discrete pilot component 1000’ also includes an input cover 1014 fixedly disposed at the open end of the piston hole 1022. The input cover 1014 includes a hydraulic passage 1008‘ through which hydraulic fluid from a hydraulic fluid source 1012 can be received. Subsequently, the hydraulic passage 1008’ is in fluid communication with a radially extending passage 1042 also formed in the input cover 1014.

[0051] The housing 1002’ also includes a first hydraulic passage 1034, a second hydraulic passage 1036, and a third hydraulic passage 1038. The first hydraulic passage 1034 (which can be formed as one or more radial passages or annular notches) is configured to align with at least one of the radially extending passages in the radially extending passage 1042 to provide fluid communication therebetween. Subsequently, the second hydraulic passage 1036 is in fluid communication with the first hydraulic passage 1034. In the illustrated example, the second hydraulic passage 1036 is formed as two or more vertical or longitudinally extending passages that intersect the third hydraulic passage 1038 to establish fluid communication with the third hydraulic passage. As shown, the third hydraulic passage 1038 may include a laterally formed passage or additional annular notches. In any case, the third hydraulic passage 1038 establishes fluid communication with the piston hole 1022 such that the hydraulic fluid supplied through the third hydraulic passage 1038 will establish a hydraulic fluid pressure that resists the biasing of the piston spring 1030.

[0052] As described above, no hydraulic fluid is applied through the hydraulic passage 1008’ and thus to the first, second, and third hydraulic passages 1034 - 1038, which will cause the check ball 1024 to continue to move away from the check ball, as Figure 10AAs shown, any hydraulic fluid within the plunger bore 1005’ is allowed to drain through the connection passage 1040 and ultimately return through the hydraulic passage 1008’. This in turn allows the plunger 1004’ to reciprocate within its bore 1005’, thereby losing any valve actuation motion applied to the discrete floating member 1000’.

[0053] On the other hand, providing hydraulic fluid through the hydraulic passage 1008’ will cause the hydraulic fluid to flow through the first, second, and third passages 1034 - 1038 and the connection passage 1040 and ultimately into the plunger bore 1005’, causing the plunger 1004’ (when unloaded by any valve actuation motion) to extend out of the plunger bore 1005’. During this time, the check ball 1024 will remain off its seat until the hydraulic pressure within the plunger bore 1005’ exceeds the combined hydraulic pressure of the hydraulic fluid flowing through the connection passage 1040 and the biasing force provided by the piston spring 1030, causing the check ball 1024 to seat against an opening disposed between the plunger bore 1005’ and the connection passage 1040. In this way, a locked amount of hydraulic fluid will be established within the plunger bore 1005’ such that the plunger 1004’ remains in its extended position, whereby the valve actuation motion applied to the discrete floating member 1000’ is not lost but rather transmitted.

[0054] As described above, it is desirable to incorporate some form of travel limitation to prevent the plunger from extending too far out of its bore within the housing. In addition to preventing excessive biasing forces from being applied to the valve train components within the valve train (particularly hydraulic lash adjusters, where in this case the hydraulic lash adjuster would not operate properly), such travel limitations can be particularly beneficial during system manufacture and / or discrete floating member deployment, where such outward biasing forces can make installation difficult or cause the discrete floating member to disassemble itself prior to installation. Figures 11 to 16 Various embodiments for implementing such travel limitation features are shown.

[0055] Figure 11 A discrete floating member 1100 is shown that can be used as Figure 3The discrete air-operated component 330 shown in the illustrated embodiment. The discrete air-operated component 1100 shown is similar in that the housing 1102 has a plunger 1110 disposed therein. However, in this case, the adjustable portion 1140 of the adjacent valve mechanism component 1150 includes a threaded portion 1142 that engages a complementary threaded portion of the valve mechanism component 1150. During installation of the discrete air-operated component 1100, the adjustable portion 1140 is adjusted to provide a maximum opening or distance between the adjacent valve mechanism components 1150, 1152 such that the discrete air-operated component 1100 can be installed without having to compress the housing 1102 and the plunger 1110 together to fit the available clearance. Once the discrete air-operated component 1100 is correctly positioned between the adjacent valve mechanism components 1150, 1152, the adjustable portion 1140 is rotated in the same manner as a conventional clearance screw to reduce the clearance between the adjacent valve mechanism components 1150, 1152. In particular, it is desirable to set the adjustable portion 1140 such that a preload is applied to the plunger spring 1116 such that the wedges 1106 (which, when placed in the locked position, cause them to engage the outer recess 1108) are positioned at a desired location along the longitudinal length of the outer recess 1108.

[0056] Figure 12 The discrete air-operated component 1200 is shown and can be used as Figure 3 the discrete air-operated component 330 shown in the illustrated embodiment. In this embodiment, the housing 1202 and the plunger 1210 of the discrete air-operated component 1200 are modified to accommodate the deployment of an expansion ring or C-ring 1230 therebetween. In particular, a circumferential recess 1232 is formed on the inner surface of the housing bore that houses the plunger 1210; in effect, the circumferential recess 1232 is a larger diameter portion of the housing bore. On the other hand, the plunger 1210 has a channel 1234 formed on its outer surface at its second end that is disposed within the housing bore, and the channel is configured to receive the expansion ring 1230. During assembly of the discrete air-operated component 1200, the expansion ring 1230 is disposed on the channel 1234 and compressed such that the expansion ring 1230 and the plunger 1210 can be inserted into the housing bore. Once the expansion ring 1230 is aligned with the circumferential recess 1232, the expansion ring 1230 expands to extend out of the channel 1234 without becoming completely disengaged therefrom. The thickness of the expansion ring 1230 and the depth of the circumferential recess 1230 are configured such that the expansion ring 1230 can travel along the longitudinal length of the circumferential recess 1232 while engaging the channel 1234. In this manner, as the plunger 1210 moves out of the housing bore (under the biasing force applied by the plunger spring), the expansion ring 1230 will eventually abut the lower limit of the circumferential recess 1232 as Figure 12As shown. When this occurs, since the expansion ring 1230 remains engaged with the channel 1234, the plunger 1210 will be prevented from moving further out of the housing bore.

[0057] Figure 13 and Figure 14 illustrates a discrete floating member 1300 that can be used as Figure 3 the discrete floating member 330 shown in the illustrated embodiment. In this embodiment, the discrete floating member 1300 includes a pin 1330 that is used to prevent overtravel of the plunger 1310 relative to the housing 1302. In particular, Figure 13 shows a view of the pin 1330 parallel to the plane of the illustration, while Figure 14 shows a view of the pin 1330 perpendicular to the plane of the illustration, i.e., rotated 90 degrees relative to Figure 13 the plane of the illustration shown. In this embodiment, as Figure 13 best shown in, the pin 1330 is rigidly mounted transversely to the plunger 1310 (i.e., along the diameter of the plunger). At the same time, as Figure 14 best shown in, the end of the pin 1330 is aligned with and disposed within an external slot 1402 formed in the housing 1402. In this embodiment, the lower boundary of the slot 1402 is configured to engage with the pin 1330 when the plunger 1310 is biased out of the housing bore. Since the pin 1330 is rigidly mounted to the plunger 1310, this engagement between the pin 1330 and the lower boundary of the slot 1402 will prevent the plunger 1310 from moving further out of the housing bore.

[0058] In Figure 13 and Figure 14In an alternative embodiment of the illustrated embodiment, where the stroke limitation is only required during the manufacturing or assembly phase, the pin 1330 can be configured to be removably mounted in a lateral channel formed in the second end of the plunger 1310. For this alternative embodiment, the slot 1402 can be replaced by a hole having a diameter substantially similar to that of the pin 1330. In this case, during the assembly of the discrete floating member 1300, the housing 1302 and the plunger 1310 can be compressed until the lateral channel of the plunger 1310 is aligned with the hole formed in the housing 1302, such that the pin 1330 can be inserted through the hole into the lateral channel, thereby effectively locking the plunger 1310 to the housing 1302. In this embodiment, the longitudinal positions of the lateral channel in the plunger 1310 and the hole in the housing 1302 are selected such that when the pin 1330 is inserted into the hole and the lateral channel, the total longitudinal length of the discrete floating member 1300 is small enough to ensure that the discrete floating member 1300 can be easily installed in the valve mechanism. Once the discrete floating member 1300 is properly positioned in the valve mechanism, the pin 1300 (which can have a suitable gripping element, such as a ring in a "grenade pin") can be removed, thereby allowing the plunger 1310 to expand out of the housing hole (again, under the biasing of the plunger spring) until further travel is impeded by the contact of the respective housing 1302 and plunger 1310 with adjacent valve mechanism components (not shown), thus completing the installation.

[0059] Figure 15 A discrete floating member 1500 is shown, which can be used as Figure 3 the discrete floating member 330 shown in the illustrated embodiment. In this embodiment, the discrete floating member 1500 again includes a housing 1502 and a plunger 1510, which are biased apart from each other by a plunger spring 1516. However, as further shown, a sheath or outer housing 1560 (only partially shown) is provided with a radially inwardly extending lower flange 1564 and is configured to be confined between the plunger spring 1516 and the flange portion 1530 of the plunger 1510. In this embodiment, the outer housing 1560 includes a plurality of tabs or fingers 1562 at its upper end, which also extend radially inwardly and are configured to engage the upper surface of the end cap 1540 of the housing 1502. Contrary to the lower flange 1564 that is confined between the plunger spring 1516 and the plunger flange 1530, if the plunger 1510 is allowed to reciprocate in the housing hole, the fingers 1562 are not attached to the end cap 1540 but are free to separate from the end cap 1540. That is, when the plunger 1510 is in an unlocked state relative to the housing 1502, the plunger 1510 can retract into the housing hole, i.e., as Figure 15The upward translation shown. Since the outer housing 1560 is effectively attached to the plunger 1510, it will also translate upward because the fingers 1562 are not attached to the end cap 1540. However, when the plunger 1510 extends out of the housing bore, under the influence of the plunger spring 1516, the outer housing 1560 will similarly translate downward, as Figure 15 shown until the fingers 1562 engage the upper surface of the end cap 1540. At this time, the lower flange 1564 of the outer housing 1560 prevents further extension of the plunger spring 1516, thereby restricting further travel of the plunger 1510.

[0060] Figure 16 A discrete floating component 1600 is shown, which can be used as the discrete floating component 330 shown in the Figure 3 embodiment shown. Similarly, the discrete floating component 1600 includes a housing 1602 and a plunger 1610. However, the shown discrete floating component 1600 differs from the foregoing embodiments in that the shown locking mechanism 1604 is configured to be in a normal unlocked state, and the plunger spring 1616 is configured to bias the plunger 1610 into a housing bore formed in the housing 1602. In this case, the locking mechanism 1604 has an internal plunger 1611 biased by an internal plunger spring 1612 (and not resisted by any hydraulic pressure), such that the wedge 1686 is allowed to retract from the outer recess 1608 and disengage from the outer recess, thereby unlocking the plunger 1610 from the housing 1602. On the other hand, when hydraulic pressure (via the hydraulic passage 1680) is applied to the internal plunger 1611, the wedge 1686 extends outward and engages the outer recess 1608, thereby locking the plunger 1610 to the housing 1602.

[0061] Additionally, given the configuration of the plunger spring 1616, it prevents the plunger 1610 from extending excessively out of the housing bore. It should be understood that this inward biasing of the plunger 1610 will prevent the plunger spring 1616 from pushing the contact surfaces of the plunger 1610 and the housing 1602 against their respective adjacent valve train components. Thus, in this embodiment, it is expected that one or more adjacent valve train components (or another upstream or downstream valve train component) will need a biasing force applied thereto such that one or both of the adjacent valve train components are biased into contact with the discrete floating component 1600.

[0062] Although various embodiments in accordance with the present disclosure have been described in connection with specific embodiments of the present disclosure, it is apparent that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, where feasible, the features of the various embodiments described herein can be employed in any one of the other embodiments described herein. As a specific example, although Figure 9AThe longitudinally extending annular channel 908' is described in connection with a generally unlocked implementation, but it should be understood that the extending annular channel 908' can be equivalently used in any of the generally locked implementations described herein.

[0063] Accordingly, the preferred embodiments of the invention set forth herein are merely illustrative and not restrictive, provided that their variations fall within the scope of the appended claims and their equivalents.

Claims

1. A discrete air-actuated device for use in a valve mechanism of an internal combustion engine, the valve mechanism having at least a first valve mechanism component and a second valve mechanism component, the air-actuated device comprising: a housing having a housing bore extending longitudinally into the housing from a first end of the housing, the housing further including a second end having a housing contact surface configured to engage a corresponding contact surface of the first valve mechanism component; and a plunger slidably disposed in the housing bore through the first end of the housing and controllable between a first state in which the plunger rigidly extends out of the housing bore and a second state in which the plunger is permitted to reciprocate in the housing bore, the plunger further including an end having a plunger contact surface configured to engage a corresponding contact surface of the second valve mechanism component, wherein the housing contact surface and the plunger contact surface are configured to support the discrete air-actuated device between the first valve mechanism component and the second valve mechanism component.

2. The discrete air-actuated device according to claim 1, wherein, the housing contact surface and the plunger contact surface are configured to permit the discrete air-actuated device to rotate relative to the first valve mechanism component or the second valve mechanism component or both.

3. The discrete air-actuated device according to claim 2, wherein, either the housing contact surface or the plunger contact surface may include a convex contact surface or a concave contact surface.

4. The discrete air-actuated device according to claim 3, wherein, either the housing contact surface or the plunger contact surface may include a spherical contact surface.

5. The discrete air-actuated device according to claim 1, wherein, the second end of the housing or the end of the plunger includes a hydraulic passage configured to receive hydraulic fluid to control the plunger between the first state and the second state of the plunger.

6. The discrete air-actuated device according to claim 5, the discrete air-actuated device further comprising: a hydraulically controlled locking mechanism configured to lock the plunger relative to the housing in the first state and unlock the plunger relative to the housing in the second state, wherein the hydraulic passage is in fluid communication with the hydraulically controlled locking mechanism.

7. The discrete air-actuated device according to claim 6, wherein, the hydraulically controlled locking mechanism defaults to a locked state and application of hydraulic fluid via the hydraulic passage causes the hydraulically controlled locking mechanism to be in an unlocked state.

8. The discrete air-actuated device according to claim 6, wherein, the hydraulically controlled locking mechanism defaults to an unlocked state and application of hydraulic fluid via the hydraulic passage causes the hydraulically controlled locking mechanism to be in a locked state.

9. The discrete air-actuated device according to claim 6, wherein, The hydraulically controlled locking mechanism includes an inner plunger slidably disposed in a longitudinal hole formed in the plunger and a radially extending locking element disposed in a radial opening formed in the plunger, and wherein the housing hole includes an annular recess that is engaged by the locking element when the locking element extends out of the radial opening.

10. The discrete air-actuated device according to claim 9, wherein, the longitudinal length of the annular recess is greater than the thickness of the locking element.

11. The discrete air-actuated device according to claim 9, wherein, the longitudinal length of the annular recess is at least large enough to accommodate the maximum spacing between the first valve mechanism component and the second valve mechanism component when the element extends out of the radial opening and engages the annular recess.

12. The discrete air-actuated device according to claim 5, the discrete air-actuated device further comprises: a check valve that is in fluid communication with the hydraulic passage and is configured to establish a certain amount of locking hydraulic fluid between the housing and the plunger.

13. The discrete air-actuated device according to claim 12, wherein, the check valve is deployed in a control valve upstream of the discrete air-actuated device.

14. The discrete air-actuated device according to claim 12, wherein, the check valve is deployed within the discrete air-actuated device.

15. The discrete air-actuated device according to claim 14, the discrete air-actuated device further comprises: a biasing pin arranged to open the check valve when hydraulic fluid is not supplied via the hydraulic passage and to allow the check valve to close when hydraulic fluid is supplied via the hydraulic passage.

16. The discrete air-actuated device according to claim 1, the discrete air-actuated device further comprises: a plunger spring that biases the plunger out of the plunger hole.

17. The discrete air-actuated device according to claim 16, wherein, the plunger spring is disposed within the housing hole.

18. The discrete air-actuated device according to claim 16, wherein, the plunger spring is disposed outside the housing.

19. The discrete air-actuated device according to claim 1, wherein, the travel of the plunger out of the housing hole is restricted.

20. The discrete air-actuated device according to claim 1, wherein, the housing contact surface or the plunger contact surface is configured to be attached to a corresponding one of the first valve mechanism component or the second valve mechanism component.

Images