Valve train for an engine
10526929 ยท 2020-01-07
Assignee
Inventors
Cpc classification
F01L2800/06
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01L1/181
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01L1/182
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01L1/2411
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01L2001/2444
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01L1/2405
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01L1/26
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F01L1/18
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01L1/24
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A valvetrain for an engine includes a pair of valves that are disposed in a spaced apart relation to one another, and in which each of the valves has an elongated valve stem. The valvetrain further includes a valve bridge that is coupled to the pair of valves. The valve bridge is configured to define a pair of receptacles to at least partly receive the pair of valve stems therein. The valve bridge further defines a central recess that is located midway between the pair of receptacles and disposed in a co-planar relationship with the pair of receptacles.
Claims
1. A valvetrain for an engine, the valvetrain comprising: a pair of valves disposed in a spaced apart relation to one another, each of the valves having an elongated valve stem; a valve bridge coupled to the pair of valves, the valve bridge configured to define a pair of receptacles to at least partly receive the pair of valve stems therein, the valve bridge further defining a central recess located midway between the pair of receptacles and disposed in a co-planar relationship with the pair of receptacles; a rocker arm rotatably supported on a rocker shaft and disposed away from the central recess of the valve bridge, the rocker arm having a contact element depending downwardly from an end of the rocker arm, the contact element including an elephant foot button configured to be adjustably supported by the rocker arm, wherein the elephant foot button has a relatively large diameter foot portion and a smaller diameter leg portion disposed between the relatively large diameter foot portion and the rocker arm; and a hydraulic lash adjuster being slidably received in the central recess of the valve bridge, the hydraulic lash adjuster having a sleeve slidably received in the central recess and having a first end of the hydraulic lash adjuster abutting a counterbored face of the valve bridge located adjacent to the central recess, and a plunger slidably received in the sleeve and having a second end of the hydraulic lash adjuster being adapted to operatively abut with the elephant foot button of the contact element of the rocker arm.
2. The valvetrain of claim 1, wherein positioning the central recess midway between the pair of receptacles facilitates an axial abutment of the elephant foot button of the contact element with the second end of the hydraulic lash adjuster such that the valve bridge is configured to simultaneously transmit an equal amount of actuating force from the rocker arm to each of the valves via the axially aligned elephant foot button of the contact element and the hydraulic lash adjuster when the rocker arm operatively executes oscillatory motion about the rocker shaft.
3. The valvetrain of claim 2, wherein the co-planar relationship of the central recess with the pair of receptacles facilitates reciprocal movement of the valve bridge in a longitudinal plane included by the central recess and the pair of receptacles when the rocker arm operatively executes oscillatory motion about the rocker shaft.
4. The valvetrain of claim 3, wherein the co-planar relationship of the central recess with the pair of receptacles is further configured to operatively prevent the valve bridge from tilting and yawing out of the longitudinal plane.
5. The valvetrain of claim 1, wherein the elephant foot button of the contact element defines a first oil passage therethrough, the first oil passage having an outlet located at an end of the elephant foot button of the contact element that is disposed in abutment with the second end of the hydraulic lash adjuster.
6. The valvetrain of claim 5, wherein the plunger of the hydraulic lash adjuster includes a second oil passage having an inlet defined at the second end of the hydraulic lash adjuster.
7. The valvetrain of claim 6, wherein positioning the central recess midway between the pair of receptacles and the co-planar relationship of the central recess midway with the pair of receptacles together facilitate an axial alignment between the outlet of the first oil passage and the inlet of the second oil passage from respective ones of the elephant foot button of the contact element and the plunger of the hydraulic lash adjuster.
8. A valve bridge for a valvetrain having a pair of valves disposed in a spaced apart relation to one another and a rocker arm rotatably supported on a rocker shaft and disposed away from the valve bridge, the rocker arm configured to execute oscillatory motion about the rocker shaft for actuating the pair of valves via the valve bridge, the valve bridge defining: a pair of receptacles configured to at least partly receive a pair of valve stems therein, the pair of valve stems being associated with the pair of valves; and a central recess located midway between the pair of receptacles and disposed in a co-planar relationship with the pair of receptacles; wherein the central recess is configured to slidably receive a hydraulic lash adjuster of the valvetrain, the hydraulic lash adjuster being operatively actuated for movement of the valve bridge by the rocker arm via a contact element depending downwardly from an end of the rocker arm, the contact element including an elephant foot button configured to be adjustably supported by the rocker arm; and wherein positioning the central recess midway between the pair of receptacles facilitates the valve bridge to simultaneously transmit an equal amount of actuating force from the rocker arm to each of the valves via the elephant foot button of the contact element and the hydraulic lash adjuster when the rocker arm operatively executes oscillatory motion about the rocker shaft; and wherein the rocker arm includes an extension on the rocker arm selected so as to assist the rocker arm in advantageously maintaining the elephant foot button of the contact element in axial alignment with the hydraulic lash adjuster when the elephant foot button of the contact element abuts the hydraulic lash adjuster during operation of the valvetrain.
9. The valve bridge of claim 8, wherein the pair of receptacles are equidistantly located from the central recess.
10. The valve bridge of claim 8 further comprising a counterbored face located adjacent to the central recess, the counterbored face being configured to abut with a first end of the hydraulic lash adjuster.
11. The valve bridge of claim 8, wherein the co-planar relationship of the central recess with the pair of receptacles facilitates reciprocal movement of the valve bridge in a longitudinal plane included by the central recess and the pair of receptacles when the rocker arm operatively executes oscillatory motion about the rocker shaft.
12. The valve bridge of claim 11, wherein the co-planar relationship of the central recess with the pair of receptacles is further configured to operatively prevent the valve bridge from tilting and yawing out of the longitudinal plane.
13. An engine comprising: a valvetrain for the engine, the valvetrain comprising: a pair of valves disposed in a spaced apart relation to one another, each of the valves having an elongated valve stem; a valve bridge coupled to the pair of valves, the valve bridge configured to define a pair of receptacles to at least partly receive the pair of valve stems therein, the valve bridge further defining a central recess located midway between the pair of receptacles and disposed in a co-planar relationship with the pair of receptacles; a rocker arm rotatably supported on a rocker shaft and disposed away from the central recess of the valve bridge, the rocker arm having a contact element depending downwardly from an end of the rocker arm, the contact element including an elephant foot button configured to be adjustably supported by the rocker arm; and a hydraulic lash adjuster being slidably received in the central recess of the valve bridge, the hydraulic lash adjuster having a first end being adapted to abut with a counterbored face of the valve bridge located adjacent to the central recess, and a second end being adapted to operatively abut with the elephant foot button of the contact element of the rocker arm, respectively; wherein positioning the central recess midway between the pair of receptacles and the co-planar relationship of the central recess midway with the pair of receptacles together facilitate an axial alignment between an outlet of a first oil passage and an inlet of a second oil passage defined by respective ones of the elephant foot button of the contact element and the hydraulic lash adjuster, such that the hydraulic lash adjuster is provided with oil when the valves undergo a dwell phase to prevent oscillatory movement of the rocker arm about the rocker shaft and maintain the valves in their closed positions.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
(8) Referring to
(9) Moreover, in other embodiments of this disclosure, the engine 100 disclosed herein may be alternatively embodied as a two stroke engine in lieu of the four stroke engine disclosed herein. Further, the engine 100 may be embodied as one of a spark ignition engine or a compression ignition engine. It should be noted that a type of fuel used is merely exemplary and hence, non-limiting of this disclosure. Persons skilled in the art will acknowledge that any suitable type of fuel may be used depending upon the type of engine 100 used and other specific requirements of an application.
(10) In the illustrated embodiment of
(11) Referring to
(12) Referring to
(13) Referring to
(14) With reference to
(15) Additionally, referring to
(16) Although the present disclosure is explained in conjunction with the contact element 124 and the hydraulic lash adjuster 128, it may be noted that in another aspect of this disclosure, embodiments disclosed herein can be similarly realized without the presence of one or both of the contact element 124 and the hydraulic lash adjuster 128. In such embodiments, one or both of the rocker arm 120 and the valve bridge 110 may be designed such that the rocker arm 120 and the valve bridge 110 may mutually co-operate with one another vis--vis the central recess 118 of the valve bridge 110 and accomplish functions that are consistent with the present disclosure i.e., in lieu of the contact element 124 and the hydraulic lash adjuster 128 disclosed herein.
(17) In embodiments of this disclosure, the positioning of the central recess 118 midway between the pair of receptacles 114, 116 facilitates an axial abutment of the contact element 124 with the second end 132 of the hydraulic lash adjuster 128 such that the valve bridge 110 is configured to simultaneously transmit an equal amount of actuating force from the rocker arm 120 to each of the inboard and outboard valves 104, 106 via the axially aligned contact element 124 and the hydraulic lash adjuster 128 when the rocker arm 120 operatively executes oscillatory motion about the rocker shaft 122.
(18) Further, referring to
(19) Referring to
(20) Additionally, as shown in
(21) With reference to
(22) Moreover, it is also known in the art that during operation of the engine 100, one or more external forces may act on each of the inlet valves 104, 106 i.e., the inboard inlet valve 104 and the outboard inlet valve 106 from fuel air charge combustion and the resulting cylinder pressure in addition to the valve spring forces. It is hereby envisioned that the equidistant positioning of the inboard and outboard valves 104, 106 with respect to the contact element 124 may help to reduce a differential in the amount of forces transmitted to each of the valves 104, 106 for opening and closing respective ones of the valves 104, 106 against the external forces mentioned above. Consequently, the differential in valve lift associated with each of the valves 104, 106 with respect to one another is reduced when the rocker arm 120 transmits actuating force to the valve bridge 110 via the contact element 124 and the hydraulic lash adjuster 128 for opening and closing of the valves 104, 106. If the contact element 124 were not to be equidistantly positioned with respect to the inboard and outboard valves 104 and 106, forces may be distributed unequally to both the valves 104 and 106 and give rise to a moment balance. Consequently the differential in valve lift between respective ones of the valves 104 and 106 would be higher. In the case of exhaust valves 105 and 107, this condition could result in the exhaust valves 105, 107 encountering different cylinder pressures further worsening force distribution between the inboard and outboard exhaust valves 105 and 107 respectively and the subsequent opening of the valves 105 and 107.
(23) Moreover, with the equidistant positioning of the inboard and outboard valves 104, 106 with respect to the contact element 124, the differential in the lifting of each valve i.e., the inboard valve 104 and the outboard valve 106 with respect to one another is minimized. This means, there would be little or no delay between the opening and closing of the respective ones of the valves 104, 106 in relation to one another. Such equidistant positioning when implemented on the pair of inlet valves 104, 106 with the help of the corresponding valve bridge 110 can therefore assist in facilitating at least an almost equal and simultaneous valve lift to each of the inlet valves 104, 106. The almost equal and simultaneous valve lift associated with the pair of inlet valves 104, 106 can beneficially cause an improvement in various operating conditions of the engine 100 such as, but not limited to, an improved swirl pattern of fuel-air charge in the cylinder, a shorter inter-mixing time of the fuel-air charge in the cylinder, an improved ignitability of the fuel-air charge in the cylinder, and an improved control in the emissions e.g., nitrous oxide (NO.sub.x) of the engine 100.
(24) Similarly, embodiments of this disclosure when implemented on the pair of exhaust valves 105 and 107 can help distribute actuation forces equally to respective ones of the exhaust valves 105 and 107. Although each of the exhaust valves 105 and 107 may encounter different cylinder pressures and valve spring pressures during operation of the engine 100, the equidistant positioning of the pair of the exhaust valves 105 and 107 from its corresponding contact element could help distribute forces uniformly between the inboard and outboard exhaust valves 105 and 107 respectively and therefore, improve the subsequent opening of the valves 105 and 107.
(25) With continued reference to
(26) Referring to
(27) Each of the support blocks 150, 152 contain one or more dowel pins 160 that are disposed in mutual alignment with corresponding ones of receptacles 162 defined on a base 164 for e.g., a rocker box of the engine 100. Each of the dowel pins 160 and their corresponding receptacles 162 are machined to close tolerances so that there is little or no play in the movement of the individual rocker arms 120, 121 when each of the rocker arms 120, 121 executes an oscillatory motion about the rocker shaft 122.
(28) Also, as best shown in
(29) Similarly, a configuration i.e., size and shape of the extension 166 on the rocker arm 121 is also selected so as to assist the rocker arm 121 in maintaining its contact element in axial alignment with the corresponding hydraulic lash adjuster when the contact element abuts the hydraulic lash adjuster during operation of the valvetrain 102. As a result, the differential in valve lift associated with each of the valves 105, 107 with respect to one another is reduced when the rocker arm 121 transmits actuating force to the valve bridge 112 via its associated contact element and the corresponding hydraulic lash adjuster for opening and closing of the valves 105, 107.
(30) Various embodiments disclosed herein are to be taken in the illustrative and explanatory sense, and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, engaged, connected, and the like) are only used to aid the reader's understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the components and/or structures disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer that two elements are directly connected to each other.
(31) Additionally, all numerical terms, such as, but not limited to, first, second, third, or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader's understanding of the various elements of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element relative to, or over, another element.
INDUSTRIAL APPLICABILITY
(32) Embodiments of the present disclosure have applicability for use and implementation in facilitating an equal valve lift, and a simultaneous actuation for a pair of valves, for example, a pair of inlet valves or a pair of exhaust valves of an engine.
(33) Many previously known designs of valve bridges may be inadvertently configured to establish two or more degrees of freedom for a pair of valves that are on the same timing arrangement, for example, a pair of inboard and outboard inlet valves, or a pair of inboard and outboard exhaust valves. With implementation of embodiments disclosed herein, manufacturers of valvetrains can potentially minimize the risk of damage, deterioration in performance and/or failure of the valves, the valve bridge, and/or other components of the valvetrain during an operation of the engine. Also, costs, time, and effort previously incurred with repair and/or replacement of parts associated with conventionally known valvetrain arrangements can be mitigated. Further, a control in various performance metrics of the engine, for example, with delivery of fuel-air charge, combustion of fuel-air charge, and exhaust characteristics can be easily improved with use of embodiments disclosed herein.
(34) While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed components and structures without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.