Cross-Reference to Related Applications:

[0001] This application claims the benefit of the filing date of U.S. Provisional App. Ser.

No. 63/224,714 filed on July 22, 2021, and U.S. Provisional App. Ser. No. 63/267,234 filed on January 28, 2022, each of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] This invention relates to internal combustion engines and, more particularly, to devices and systems that include an engine rocker lever and a biasing mechanism to maintain contact between the rocker lever and the camshaft.

BACKGROUND

[0003] Rocker levers are employed in the valve trains of internal combustion engines to transfer motion from a camshaft to intake and/or exhaust valves of an internal combustion engine. It is important for the rocker lever to be able to be rotated by the camshaft during engine operation. Current techniques for linking the camshaft to the rocker lever suffer deficiencies in performance and packaging on the engine, and in maintaining the link between the camshaft and the rocker lever. Therefore, further improvements in this technological area are desired.

SUMMARY

[0004] Systems and devices are disclosed herein relating to a rocker lever of an internal combustion engine that transfers motion from the camshaft to one or more intake or exhaust valves of an engine cylinder head. A biasing mechanism is provided to bias the rocker lever to maintain an operative association with the camshaft.

[0005] In an embodiment, the biasing mechanism is a spring-biased tappet that normally biases the rocker lever to maintain an operative association between the rocker lever and the camshaft. In an embodiment, the rocker lever is maintained in direct contact with the camshaft. [0006] In an embodiment, the biasing mechanism is provided on a component mounted to the engine block and/or cylinder head. In an embodiment, the component is a cam carrier. [0007] In an embodiment, the biasing mechanism contacts the cam shaft to bias the rocker lever in operative association with the camshaft. In an embodiment, the biasing mechanism in incorporated into the body of the rocker lever. In an embodiment, the biasing mechanism maintains the rocker lever in direct contact with the camshaft.

[0008] This summary is provided to introduce a selection of concepts that are further described below in the illustrative embodiments. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. l is a schematic diagram of a rocker lever and biasing mechanism according to one embodiment of the present disclosure.

[00010] FIG. 2 is a schematic diagram of a rocker lever, camshaft, biasing mechanism, and valve according to another embodiment of present disclosure.

[00011] FIG. 3 is a schematic diagram of an internal combustion engine embodiment with which embodiments of FIGs. 1 and 2 can be employed.

[00012] FIG. 4 is a section view of an embodiment of a rocker lever, camshaft, and biasing mechanism with the biasing mechanism housed in a component mounted to the engine block.

[00013] FIG. 5 is a schematic view of an embodiment of a rocker lever, camshaft, and biasing mechanism with the biasing mechanism housed in the rocker lever.

[00014] FIG. 6 is an elevation view of an embodiment of the rocker lever and biasing mechanism of FIG. 5.

[00015] FIG. 7 is a sectional view of the rocker lever and biasing mechanism of FIG. 6.

DETAILED DESCRIPTION

[00016] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, any alterations and further modifications in the illustrated embodiments, and any further applications of the principles of the invention as illustrated therein as would normally occur to one skilled in the art to which the invention relates are contemplated herein.

[00017] FIG. 1 shows a schematic of a rocker lever device 10 for an internal combustion engine that includes a camshaft and a rocker shaft. The rocker lever device 10 includes a rocker lever 12 with a body 14 rotatable about the rocker shaft. The body 14 includes a first end 16 that receives motion from the camshaft and a second end 18 that transfers the motion to at least one valve. A biasing mechanism 20 biases the rocker lever 12 to maintain operative association of the first end 16 of the rocker lever 12 with the camshaft.

[00018] As used herein, “operative association” means the rocker lever 12 can be in direct contact with or in indirect contact with the camshaft. For example, indirect contact of the rocker lever 12 with the camshaft can be provided through a linkage or other device, so long as one or more camshaft lobes of the camshaft is operative to rotate the rocker lever 12 to effect a valve opening event.

[00019] FIG. 2 shows a schematic of a system 50 for an internal combustion engine. System 50 includes a rocker shaft 52 and a rocker lever 54 rotatably mounted about the rocker shaft 52. The rocker lever 54 includes a first end 56 and a second end 58 opposite the first end 56. System 50 includes a camshaft 60 that rotates the rocker lever 54 about the rocker shaft 58. System 50 includes a biasing mechanism 62 that biases the first end 56 of the rocker lever 54 toward the camshaft 60. System 50 includes at least one valve 64 connected to the second end 58 of the rocker lever 54 that is opened and closed by rotation of the rocker lever 54 about the rocker shaft 52.

[00020] FIG. 3 shows an internal combustion engine 100 with which the device 10 or system 50 can be employed. Internal combustion engine 100 includes an engine block 102, a cylinder head 103, an intake system 104, and an exhaust system 106. Engine 100 can be any type of engine, and in one specific embodiment is a combustion engine that combusts any suitable fuel and includes a number of cylinders 108 each housing a piston. Cylinders 108 receive an intake flow 114 and combust a fuel provided thereto to produce an exhaust flow 116 from each of the cylinders 108. In the illustrated embodiment, engine 100 includes six cylinders connected with an intake manifold 110 and an exhaust manifold 112. Engine 100 can be an in line type engine with a single cylinder bank, although other embodiments include V-shaped cylinder arrangements, a W-type engine, or any engine arrangement with one or more cylinders. It is contemplated that engine 100 is provided as part of a powertrain for a vehicle (not shown), although other applications are also contemplated and not precluded, such as for gensets and marine applications.

[00021] Referring to FIG. 4, there is illustrated one embodiment of a portion of block 102 of engine 100 including a portion of the valvetrain 200 at a cylinder 108. The illustrated valvetrain portion 200 includes a valve opening mechanism 270 to open one or more intake and/or exhaust valves 142 at a cylinder 108 of engine 100. For example, each cylinder 108 includes at least one valve 142, such as an intake valve or exhaust valve, that is opened and closed by valve opening mechanism 270 via one or more cam lobe(s) 152 of camshaft 150. The opening of the valve(s) 142 allows a charge flow to be admitted into the combustion chamber 130 of, or exhaust flow to be discharged from, the respective cylinder 108 through an opening into the combustion chamber 130 that is selectively opened and closed by valve 142.

[00022] The valve(s) 142 is connected to a rocker lever device 201. Rocker lever device 201 includes a rocker lever 202 that is rotatable about a rocker shaft 204 in response to a valve opening cam lobe 152 of camshaft 150 pushing on the rocker lever 202. The rotation of the rocker lever 202 about the rocker shaft 204 causes the valve(s) 142 to open in response to the cam lobe 152 acting on rocker lever 202.

[00023] The rocker lever 202 includes a body 208 extending between a first end 210 on one side of rocker shaft 204 and a second end 212 on an opposite side of rocker shaft 204. Body 208 also includes an upper portion or side 214 above rocker shaft 204 and a lower portion or side 216 extending below rocker shaft 204. The upper and lower sides 214, 216 extend between first end 210 and second end 212.

[00024] In the illustrated embodiment, first end 210 includes a roller 220 rotatably mounted to body 208. Roller 220 is biased into contact with camshaft 150 by the biasing mechanism 230 housed in a component 218 mounted to engine block 102. In an embodiment, the component 218 is a cam carrier to which the camshaft 150 is mounted. Other embodiments contemplate other types of components 218 for housing the biasing mechanism 230, such as cylinder head 103 or other structure attached directly or indirectly to block 102.

[00025] The biasing mechanism 230 is biased outwardly away from component 218 to normally contact body 208 of rocker lever 202 on lower side 216 thereof. The biasing force supplied by biasing mechanism 230 rotates rocker lever 202 in the direction of arrow 206 about rocker shaft 204 so that roller 220 maintains contact with camshaft 150. As a result, the rocking motion in the direction opposite arrow 206 that is imparted by the non-circular cam lobes 152 of camshaft 150 acting on roller 220 are reliably transferred by rocker lever 202 to the valve(s) 142 connected to the second end 212 of rocker lever 202.

[00026] The rocker lever body 208 includes a passage 228 for receiving the rocker shaft 204. A bushing (not shown) may be provided in passage 228 around the rocker shaft 204. Passage 228 and rocker shaft 204 extend along a first axis 222, and the biasing mechanism 230 extends along a second axis 224. In the illustrated embodiment, the biasing mechanism 230 and therefore the second axis 224 is located between the rocker shaft 204 and second end 212 of body 208. The second axis 224 is transverse to the first axis 222 so the biasing mechanism 230 imparts a rotary moment to rocker lever 202 to rotate body 208 in the direction of arrow 206. In one embodiment, the second axis 224 is orthogonal to first axis 222 and extends vertically out of block 102 and/or cylinder head 103. Non-orthogonal orientations between axes 222, 224 may also be employed.

[00027] In the illustrated embodiment, the biasing mechanism 230 includes a bore 234 for receiving a spring 236 that normally biases the biasing mechanism 230 into contact with the rocker lever 202. In an embodiment, the biasing mechanism 230 includes a cylindrical tappet 232 housed in a receptacle 226 formed in component 218. The tappet 232 includes an inner bore 234 facing toward component 218. The spring 236 is located in receptacle 226 and bore 234, and contacts component 218 and tappet 232. Spring 236 outwardly biases the tappet 232 outwardly from component 218 so that the outer end 238 of tappet 232 maintains contact with body 208 of rocker lever 202 along lower side 216.

[00028] The outer end 238 of tappet 232 is convexly curved to facilitate rotation of rocker lever 202 against the outer end 238 in the illustrated embodiment. Embodiments with a flat outer end 238 or other shapes are also contemplated. Tappet 232 may be captured in bore 234 with a blocking mechanism 244, such as a retaining clip. The tappet 232 can reciprocally move in receptacle 226 to compress spring 236 in response to rocker lever 202 rotating in a direction opposite arrow 206. Spring 236 forces tappet 232 outwardly to maintain contact between tappet 232 and rocker lever 202 as rocker lever 202 rotates in the direction of arrow 206, and which maintains the first end of rocker lever 210 into operative association with the camshaft 150. [00029] Second end 212 of rocker lever 202 is connected to valve(s) 142 via a piston 250 in the illustrated embodiment. Other embodiments contemplate an e-foot, crosshead, or any suitable structure that connects the rocker lever 202 to one or more valve(s) 142. In an embodiment, piston 250 can be selectively locked and unlocked depending on whether or not rocking motion is to be transferred to valve(s) 142. In another embodiment, piston 250 is fixed so that rocking motion is always transferred to valve(s) 142.

[00030] Referring to FIG. 5, there is illustrated one embodiment of a portion of engine 100 including a portion of the valvetrain at a cylinder 108. The illustrated portion includes a piston 140 connected to a crankshaft (not shown), a camshaft 150, and a valve opening mechanism 170. Piston 140 is housed in a respective one of the cylinders 108, and is rotatably connected to crankshaft with a connecting rod so that reciprocating movement of piston 140 rotates the crankshaft, as is known in the art. The crankshaft may be connected to camshaft 150 via gears (not shown) or other suitable arrangement such as chains or belts so that rotation of crankshaft rotates camshaft 150 at, for example, half speed of crankshaft with the connection arrangement providing a gear reduction, as known in the art.

[00031] Each cylinder 108 also includes at least one valve 142, such as an intake valve or exhaust valve, that is opened and closed by valve opening mechanism 170 via cam lobes 152 of camshaft 150. The opening of the valve(s) 142 allows a charge flow to be admitted into the combustion chamber 130 of the respective cylinder 108 through one or more openings 132. In the illustrated embodiment, the valve 142 includes first and second valves 142 connected by a cross head 148 for controlling the respective openings 132 into combustion chamber 130.

[00032] The cross head 148 is connected to a rocker lever device 300. Rocker lever device 300 includes a rocker lever 302 that is rotatable about a rocker shaft 304 in response to a valve opening cam lobe 152 of camshaft 150 pushing on the rocker lever 302. The rotation of the rocker lever 302 about the rocker shaft 304 causes the valve(s) 142 to open in response to the cam lobe 152 acting directly or indirectly on rocker lever 302. [00033] Referring further to FIGs. 6-7, further details of the rocker lever device 300 are shown. The rocker lever 302 includes a body 308 extending between a first end 310 on one side of rocker shaft 304 and a second end 312 on an opposite side of rocker shaft 304. Body 308 also includes an upper portion or side 314 above rocker shaft 304 and a lower portion or side 316 projecting below rocker shaft 304. The upper and lower portions 314, 316 extend between first end 310 and second end 312.

[00034] In the illustrated embodiment, first end 310 includes a roller 320 rotatably mounted to body 308. Roller 320 is biased into operative association with camshaft 150 by the biasing mechanism 330 housed in lower portion 316 of body 308. The biasing mechanism 330 is biased to normally contact the camshaft 150. The biasing force supplied by biasing mechanism 330 rotates rocker lever 302 in the direction of arrow 306 about rocker shaft 304 so that roller 320 is maintained in operative association with camshaft 150, as shown in FIG. 5. As a result, the rocking motion in the direction opposite arrow 306 that is imparted by the non-circular cam lobes 152 of camshaft 150 acting on roller 320 are reliably transferred by rocker lever 302 to the valve(s) 142 connected to the second end 312 of rocker lever 302.

[00035] The rocker lever body 308 includes a passage 328 for receiving the rocker shaft 304. A bushing 360 may be provided in passage 328 around the rocker shaft 304. Passage 328 and rocker shaft 304 extend along a first axis 322, and the biasing mechanism 330 extends along a second axis 324. In the illustrated embodiment, the biasing mechanism 330 and therefore the second axis 324 is located below the rocker shaft 304. The second axis 324 is transverse to the first axis 322 so the biasing mechanism 330 imparts a rotary moment to rocker lever 302 to rotate body 308 in the direction of arrow 306. In one embodiment, the second axis 324 is orthogonal to and below the first axis 322. Non-orthogonal orientations may also be employed. [00036] In the illustrated embodiment, the biasing mechanism 330 includes a cylindrical tappet 332 housed in a receptacle 326 formed in lower portion 316 of body 308 of rocker lever 302. The tappet 332 includes an inner bore 334 facing toward body 308. A spring 336 is located in receptacle 326 and bore 334, and contacts body 308 and tappet 332. Spring 336 outwardly biases the tappet 332 so that the outer end 338 of tappet 332 maintains contact with camshaft 150. The outer end 338 of tappet 332 is convexly curved to facilitate rotation of camshaft 150 against the outer end 338 in the illustrated embodiment. Embodiments with a flat outer end 338 or other shapes are also contemplated. [00037] Tappet 332 may also include a sidewall 340 with a slot 342 extending therethrough. A pin 344 engaged to rocker lever 302 extends into slot 342 to secure tappet 332 to lower portion 316 of body 308. The tappet 332 can reciprocally move in receptacle 326 along pin 344 as spring 336 forces the tappet 332 outwardly into contact with the camshaft 150.

[00038] Second end 312 of rocker lever 302 is connected to valves 142 via a piston 350 in the illustrated embodiment. Other embodiments contemplate an e-foot or any suitable structure that connects the rocker lever 302 to crosshead 148. The piston 350 can be any suitable device for engagement to valve(s) 142 via a cross-head 148, tappet, shaft, etc. In an embodiment, piston 350 can be selectively locked and unlocked depending on whether or not rocking motion is to be transferred to valve(s) 142. In another embodiment, piston 350 is fixed so that rocking motion is always transferred to valve(s) 142. Upper portion 314 of body 308 may also include a fluid control valve 352, such as is shown in the illustrated embodiment of FIG. 7. However, a fluid control valve 352 is not required and may be omitted in other embodiments.

[00039] Many aspects of the present invention are envisioned. For example, one aspect is directed to a rocker lever device for an internal combustion engine including a camshaft. The rocker lever device includes a rocker lever including a body rotatable about a rocker shaft. The body includes a first end that receives motion from the camshaft and a second end that transfers the motion to at least one valve. The rocker lever device also includes a biasing mechanism that biases the rocker lever to maintain operative association of the first end of the rocker lever with the camshaft.

[00040] In an embodiment, the biasing mechanism includes a tappet in contact with the rocker lever that biases the rocker lever in a first rotational direction about the rocker shaft toward the camshaft. In a refinement of the embodiment, the biasing mechanism includes a spring that normally biases the tappet into contact with the rocker lever. In a refinement of the embodiment, the tappet includes a convexly curved outer end that contacts the rocker lever at a location between the rocker shaft and the second end of the rocker lever.

[00041] In an embodiment, the biasing mechanism includes a bore for receiving a spring therein that normally biases the biasing mechanism into contact with the rocker lever. In an embodiment, the biasing mechanism is housed in a carrier of the camshaft or in a cylinder head of the internal combustion engine. [00042] In an embodiment, the rocker lever includes a passage for receiving the rocker shaft. The passage extends along a first axis, and the biasing mechanism extends along a second axis that is transverse to the first axis. In a refinement of the embodiment, the second axis is located between the first axis and the second end of the rocker lever.

[00043] In an embodiment, the rocker lever includes a receptacle and the biasing mechanism is housed in the receptacle of the rocker lever. In a refinement of the embodiment, the biasing mechanism projects outwardly from the rocker lever in order to contact the camshaft. [00044] Another aspect is directed to a system for an internal combustion engine. The system includes a rocker shaft and a rocker lever rotatably mounted about the rocker shaft. The rocker lever includes a first end and a second end opposite the first end. The system also includes a camshaft that rotates the rocker lever about the rocker shaft and a biasing mechanism that biases the first end of the rocker lever toward the camshaft. The system also includes at least one valve connected to the second end of the rocker lever that is opened and closed by rotation of the rocker lever about the rocker shaft.

[00045] In an embodiment, the first end of the rocker lever includes a roller that is in direct contact with the camshaft. In an embodiment, the biasing mechanism includes a spring located in the cam carrier that is housed in a bore of the biasing mechanism.

[00046] In an embodiment, the system includes a cam carrier to which the camshaft is mounted, and wherein the biasing mechanism is housed in the cam carrier. In a refinement of this embodiment, the biasing mechanism includes an outwardly biased tappet that is movably received in a receptacle of the cam carrier. In a further refinement of this embodiment, the biasing mechanism includes a spring in the receptacle that extends between and contacts the cam carrier and the tappet. In another further refinement of this embodiment, the tappet contacts the rocker lever between the rocker shaft and the second end of the rocker lever. In another refinement of this embodiment, the biasing mechanism is located below the rocker lever and projects upwardly from the cam carried into direct contact with the rocker lever.

[00047] In an embodiment, the rocker lever includes an upper side extending between the first and second ends and an opposite lower side extending between the first and second ends, and the biasing mechanism contacts the lower side of the rocker lever between the rocker shaft and the second end of the rocker lever. [00048] In an embodiment, the rocker lever includes a receptacle, and the biasing mechanism is housed in the receptacle and projects outwardly from the receptacle into contact with the camshaft. In an embodiment, the system includes a cylinder head, and the biasing mechanism is housed in the cylinder head.

[00049] While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain exemplary embodiments have been shown and described. Those skilled in the art will appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.