Cross-Reference to Related Applications

[001] This application claims the benefit of priority of U.S. Provisional Patent Application No. 63/209,265, filed June 10, 2021, which is incorporated herein by reference in its entirety.

Field

[002] This application relates to rocker arms with hydraulic circuits for enabling more than one valve lift event.

Background

[003] Prior hydraulic designs require, for example, complex, angled passages along with numerous bores. The complexity of these designs make implementation difficult.

SUMMARY

[004] The methods and devices disclosed herein overcome the above disadvantages and improves the art by way of improved oil control for a rocker arm.

[005] An oil control assembly can comprise: a capsule comprising: a first piston; a second piston; and a capsule biasing mechanism biasing the first piston from the second piston; wherein the first piston and the second piston define a chamber for receiving fluid.

[006] An oil control assembly can include a second piston coupled to a pushrod.

[007] An oil control assembly can include a rocker arm and a first piston connected to the rocker arm through a coupling mechanism.

[008] An oil control assembly can comprise a coupling mechanism wherein the coupling mechanism is a lash adjuster.

[009] An oil control assembly can comprise a first piston and a second piston connected to an oil supply path configured for actuation or de-actuation by fluid from the oil supply path. [010] An oil control assembly can comprise an oil supply path comprising a one-way valve.

[011] An oil control assembly can comprise an accumulator flow path fluidly connected to an oil supply path, the accumulator flow path comprising a spool valve and an accumulator assembly.

[012] An oil control assembly can comprise an accumulator assembly comprising a receiver and an accumulator biasing mechanism located in an accumulator chamber.

[013] An oil control assembly can comprise a spool valve coupled to an oil control path.

[014] An oil control assembly can comprise a first piston and a second piston actuated in opposite directions.

[015] An oil control assembly can comprise a capsule comprising: a first piston; a second piston facing the first piston to form a chamber; and a capsule biasing mechanism in the chamber; an accumulator assembly connected to an accumulator flow path on a first side of the capsule; a one-way valve coupled to an oil supply path, the oil supply path connected on a second side of the capsule; and a spool valve positioned to intersect the accumulator flow path, wherein the first piston and the second piston are selectively actuated or deactuated by controlling fluid to the chamber, the accumulator assembly, the one-way valve, and the spool valve.

[016] A valvetrain can comprise: an oil control assembly; a rocker arm configured to seat against a first piston; and a pushrod configured to seat against a second piston.

[017] A valvetrain can comprise a pushrod coupled to a roller lifter.

[018] A valvetrain can comprise a cylinder head, wherein an oil control assembly is installed in the cylinder head

[019] A valvetrain can comprise a cylinder head and a carrier seated on the cylinder head, and wherein an oil control assembly is installed in the carrier.

[020] Additional objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. The objects and advantages will also be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

[021] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[022] Figure 1 (a) is a cross-section view of an oil control assembly.

[023] Figure 1 (b) is a cross-section view of an oil control assembly with a partial flow diagram.

[024] Figure 2 is a graph illustrating the behavior of an oil control assembly.

[025] Figure 3(a) - 3(e) are cross-section view of an oil control assembly with

DETAILED DESCRIPTION

[026] FIG. 1 (a) illustrates a cut-away view of an oil control assembly. Oil control assembly 101 can form a standalone component or can constitute a portion of a greater valvetrain carrier or assembly. For example, oil control assembly 101 can be mounted in numerous locations, including as a tower installation, a carrier installation, or in a cylinder head. Oil control assembly 101 can comprise a high- pressure capsule 102, an oil supply path 103, a one-way valve 104, an accumulator flow path 130 with a discharge orifice 105, a spool valve 106, an oil control path 107, and an accumulator assembly 108. One-way valve 104 can be a “no-return” valve or check valve or controllable valve subject to controller 129.

[027] Capsule 102 comprises at least a first piston 109, second piston 110, and biasing mechanism 111. As shown in FIG. 1 (a), first piston 109 and second piston 110 can be cup-shaped, or have a U-shaped profile, though other configurations are possible. First piston 109 and second piston 110 can also have similar or differing dimensions. Biasing mechanism 111 can comprise a spring such as a coil spring, wave spring, leaf spring or other device configured to assist in pushing the first piston 109 away from the second piston 110. Biasing mechanism 111 can be configured to oppose forces conveyed from one or both of a pivot end of the rocker arm 115 or a pushrod 122. First piston 109 and second piston 110 can form a chamber 112 for receiving oil or other fluid. As shown, oil supply path 103 connects to one side of capsule 102 while accumulator flow path 130 connects to another side of capsule 102. While shown directly opposite in the drawings, other configurations are possible. But, what can be seen in the figures is the ease of manufacturing of the pathways and bores (oil supply path 103, one-way valve 104 seating, oil control path 107, accumulator flow path 130, piston bore 132, etc.). The pathways and bores are straightforward to cast or drill into a body of material, and so the arrangement is easily created in a carrier, tower or the engine block and the design facilitates drop-in assembly techniques. Many complex and angled pathways are eliminated over the prior art.

[028] Accumulator assembly 108 can comprise an accumulator chamber 131 with a receiver 113 and an accumulator biasing mechanism 114. Accumulator assembly 108 can be configured to store a predetermined amount of fluid when receiver 113 is moved to a first position by biasing mechanism 114, then accumulator assembly 108 can discharge the fluid when receiver 113 is moved to a second position by biasing mechanism 114. Accumulator assembly 108 is useful to store pressurized fluid and to dispense it according to a control strategy. For example, since spool valve 106 intersects the accumulator flow path 130, spool valve 106 can be controlled, whether by its default bias position or by fluid control to oil control path 107, to permit fluid to accumulate in or release from the accumulator assembly 108. Likewise, spool valve 106 can be moved to block accumulator flow path 130 to trap fluid in the accumulator assembly 108 or to block fluid from accumulating in the accumulator assembly 108.

[029] A rocker arm 115 rotates about a rocker shaft 116. First piston 109 of oil control assembly 101 can be coupled to rocker arm 115 via a coupling mechanism 117. Coupling mechanism 117 can, as illustrated, be a mechanical lash adjuster and e-foot combination though other linkages can be implemented. For example, coupling mechanism 117 can instead be a hydraulic lash adjuster or another coupling device. For example, a ball and socket arrangement can be made, where the first piston 109 includes a socket portion and the rocker arm 115 comprises a ball portion. Other mechanisms to form a pivot location between the rocker arm 115 and the first piston 109 can be devised.

[030] Rocker arm 115 can also be seated against first piston 109. Seating can be achieved by coupling mechanism 117 being positioned in contact with first piston 109 in which a pivot end of rocker arm 115 can press against first piston 109 directly through a pivot location or indirectly through a lash adjuster that is itself connected to rocker arm 115, among other options. Rocker arm 115 can be coupled directly to one or more valves 118 or, as shown in FIG. 1 , rocker arm 115 can be coupled to valves 118 via valve bridge 119 or other intermediary device or devices. Therefore, rocker arm 115 can be coupled to a single valve 118 or multiple valves 118.

[031] Second piston 110 of oil control assembly 1 can be coupled to a cam 120 via roller lifter 121 and pushrod 122. Pushrod 122 is illustrated as having a socket portion and second piston 110 is shown with a ball portion, though other linkages can be implemented. As shown, cam 120 can include cam lobe 123. Cam lobe 123 can comprise a base circle portion and one or more lift portions. As illustrated, two lift lobes are shown, though other cam lobe configurations can be implemented.

[032] Fig. 1 (b) illustrates one possible hydraulic flow diagram for oil control assembly 101. As one example, controller 129 can be connected to run an engine pump that can be powered to pressurize fluid. Using this example, pump 126 draws fluid from sump 125 which fluid can then be conveyed to one-way valve 104 as well as oil control valve 127. Pump 126 can be connected to an electric motor subject to controller 129, or pump 126 can be connected to the oil pump for the engine, as examples. In the second example, sump 125 can be the same as that used for engine oil. This simplifies the oil circuit, eliminating some control complexity from Figure 1(b). For example, one-way valve 104 can receive engine oil from the engine (pump 126), control valve 127 can be controlled by controller 129 and can receive engine oil directly from the engine, and then a single return path can be formed to sump 125. Alternatively, control valve 127 can be opened or closed depending on fluid pressure and controller 129 can be eliminated altogether.

[033] One-way valve 104 can then supply fluid to oil supply path 103. Similarly, oil control valve 127 can be controlled via controller 129 to supply fluid to oil control path 107. Optionally, pressurized fluid from accumulator assembly 108 can be directed to an optional controllable return flow valve 128 for supply to oil control valve 127 or to return fluid to sump 125. Optionally, oil control valve 127 can be configured such that it prevents flow along oil control path 107 when oil control valve 127 is de-actuated and allows flow along oil control path 107 when oil control valve 127 is actuated.

[034] Oil control valve 127 can be controlled via controller 129 to supply pressurized control fluid to oil control path 107 to actuate or deactuate spool valve 106 which spool valve 106, in turn, regulates accumulator flow path 130, directing fluid flow between chamber 112 and accumulator assembly 108 through discharge orifice 105. Spool valve 106 can be positioned to intersect accumulator flow path 130. A spool bore 160 can be cross-drilled or cast or otherwise made so that the spool valve 106 can be controlled to impact fluid flow in accumulator flow path 130.

[035] Spool valve 106, as one option, can be a slidable member with a blocking portion 163 and a flow portion 164. A plug 161 can seal the spool bore 160. Spool valve 106, as a design option, can be biased to either block the accumulator flow path 130 with blocking portion 163 or can be biased to permit flow through flow portion 164. A spool bias mechanism 162, such as a leaf or coil spring, can be placed either against the plug 161 or against the bottom of spool bore 160, as the design choice dictates. Oil control path 107 can be positioned above or below the spool valve 106 to oppose the spool bias mechanism 162. Then, when fluid is supplied to oil control path 107, it can slide the spool valve 106. As drawn, spool bias mechanism 162 is seated against plug 161 to push the blocking portion 163 to block the accumulator flow path 130. Then, fluid supplied to oil control path 107 can actuate the spool valve 106 to move the flow portion 164 to align with the accumulator flow path 130. A cross-drill, a gland, a neck, or the like options can be used to form the flow portion 164 in the spool valve 106. Plug 161 can include many options such as a threaded member, press-fit, or the like. Spool bias mechanism 162 could also be placed to slide the plug 161 in spool bore 160 and have its bias position in the cylinder head, tower, or carrier, as the case may be. Fluid pressure to actuate spool 106 can be supplied via the pump 126

[036] Return flow valve 128 is optionally included to regulate the return of fluid from accumulator assembly 108. While a fluid connection to accumulator assembly 108 is schematically shown, it is alternatively possible to include a controlled orifice in accumulator flow path 130 and to connect the controlled orifice to return fluid from the accumulator to the sump 125. Return flow can also originate from other areas of oil control assembly 101 , such as chamber 112 in addition to, or in lieu of, return flow from accumulator assembly 108. Fluid from optional return flow valve 128 can be received by sump 125.

[037] Pump 126, one-way valve 104, oil control valve 127, and optional return flow valve 128 can be managed by controller 130. Optionally, one-way valve 104 can be a one-way valve or no return valve that is regulated by fluid pressure, then no physical controller or actuator needs to be connected to one-way valve 104. Controller 129 can comprise a processor, memory device, and stored algorithms for executing a control strategy for pump126 and the valves. While controller 129 is illustrated as a single controller, it can manifest as multiple controllers.

[038] Fig. 2 is a graph illustrating the behavior of oil assembly 1.

[039] Curve 201 describes the movement of valve 118 during the operation of oil assembly 1 in a short event. For curve 201 , the y-axis represents the magnitude of valve motion over cam lobe 123 rotation which runs along the x-axis. The curve 201 can correspond to the shape of cam lobe 123.

[040] Curve 202 represents the motion of valve 118 during operation of oil assembly 1 during a long event. For curve 202, the y-axis represents the magnitude of valve motion over cam rotation which runs along the x-axis. As will be described below, curve 202 more roughly corresponds to the profile of cam 120 and its cam lobe 123. By controlling the fluid pressure in chamber 112, an extended boot shape valve lift profile can be accomplished and thereby can extend the lift from position 206 to position 207. So, the operation of oil assembly 1 can be controlled to convey a valve lift profile to valve 118 that augments the profile of the cam lobe 123.

[041 ] Curve 203 describes the motion of valves 118 with a less complicated cam profile conveyed. Capsule 102 is collapsed, such that much of the lift generated by cam lobe 123 is lost.

[042] Curve 204 describes a reference-point standard lift of the valves 118 under a less complex cam lobe profile and control strategy, the y-axis representing the magnitude of lift of the valves 118 over time along the x-axis.

[043] Position 205 can represent the point where valves 118 open during a regular or long lift event. Position 209 can represent a point where valves 118 open during a short event. Position 206 can represent the point where valves 118 close during a short event. Position 207 can represent the point where valves 118 close during a long event. Position 208 can represent a reset point, where curve 202 can transition into curve 201. Such reset point can correspond to the operation of oil assembly 1 to expand the chamber 112 by feeding fluid through one-way valve 104 to push the first piston 109 and the second piston 110 apart.

[044] FIG. 3(a) illustrates the relative motion of components, and the flow of fluids, in oil control assembly 101.

[045] During a short event, cam 120 rotates such that cam lobe 123 pushes against roller lift 121. This force is transmitted via pushrod 122 to second piston 110. One-way valve 104 is opened by controller 129. Fluid flowing through one-way valve 104 through oil supply path 103 fills chamber 112, pressurizing capsule 102 and separating first piston 109 from second piston 110, such that first piston 109 moves towards coupling mechanism 117 and second piston 110 moves towards pushrod 112. The upward motion exerted on second piston 110 by pushrod 122 is transmitted to first piston 109 via the pressurized fluid. In turn, first piston 109 drives coupling mechanism 117 upwards and rocker arm 115 rotates about rocker shaft 116. Valves 118 are moved directly by rocker arm 115, or via valve bridge 119, according to curve 202 wherein the profile of cam 120, including cam lobe 123, is transmitted to valves 118.

[046] As seen in FIG. 3(b), once valves 118 reach maximum valve lift, first piston 109 moves past discharge orifice 105 and pressurized oil from chamber 112 of capsule 102 leaks out via discharge orifice 105 and spool valve 106 into accumulator assembly 108 via accumulator flow path 130. This occurs if, as drawn, flow portion 164 of spool valve 106 is aligned with accumulator flow path 130. But if blocking position 163 of spool valve 106 is aligned with accumulator flow path 130, the fluid pressure in chamber 112 can be locked for additional rotations of cam 120.

[047] As shown in FIG. 3(c), with the flow portion 164 aligned with the accumulator assembly 108, the loss of pressurized fluid in chamber 112 collapses capsule 102 such that first piston 109 and second piston 110 compress biasing mechanism 111. As one option, first piston 109 can contact second piston 110, or the spring force of biasing mechanism 111 can hold first piston 109 and second piston 110 apart. As a working example, the capsule 102 can collapse with a timing configured so that curve 202 transitions to curve 201 at reset point 208.

[048] As seen in FIG. 3(d), once cam 120 rotates past cam lobe 123 into a cam base circle position, biasing mechanism 114 in accumulator assembly 108 and receiver 113 will push fluid in the accumulator assembly 108 back into chamber 112 of capsule 102 via the accumulator flow path 130, through discharge orifice 105 and spool valve 106. In combination with biasing mechanism 111 of capsule 102, this pressurized oil drives first piston 109 and second piston 110 apart again. The one- way valve 104, being a one-way valve or valve controlled to a closed position, prevents the pushed fluid from exiting out oil supply path 103.

[049] For the long event of curve 202 and shown in FIG. 3(e), oil control valve 127 will release oil along oil control path 107, closing spool valve 106. This prevents oil in accumulator assembly 108 from leaving and entering the pressurized capsule 102. This prevents valves 118, moving along curve 202, from transitioning into curve 201 at the reset point 208, and therefore valves 118 will convey their full lift along curve 202, opening at point 205 and closing later at point 207.

[050] Other implementations will be apparent to those skilled in the art from consideration of the specification and practice of the examples disclosed herein.

[051] In view of the foregoing, it can be said that an oil control assembly can comprise:

[052] An oil control assembly can comprise: a capsule comprising: a first piston; a second piston; and a capsule biasing mechanism biasing the first piston from the second piston; wherein the first piston and the second piston define a chamber for receiving fluid.

[053] An oil control assembly can include a second piston coupled to a pushrod.

[054] An oil control assembly can include a rocker arm and a first piston connected to the rocker arm through a coupling mechanism.

[055] An oil control assembly can comprise a coupling mechanism wherein the coupling mechanism is a lash adjuster.

[056] An oil control assembly can comprise a first piston and a second piston connected to an oil supply path configured for actuation or de-actuation by fluid from the oil supply path. [057] An oil control assembly can comprise an oil supply path comprising a one-way valve.

[058] An oil control assembly can comprise an accumulator flow path fluidly connected to an oil supply path, the accumulator flow path comprising a spool valve and an accumulator assembly.

[059] An oil control assembly can comprise an accumulator assembly comprising a receiver and an accumulator biasing mechanism located in an accumulator chamber.

[060] An oil control assembly can comprise a spool valve coupled to an oil control path.

[061] An oil control assembly can comprise a first piston and a second piston actuated in opposite directions.

[062] An oil control assembly can comprise a capsule comprising: a first piston; a second piston facing the first piston to form a chamber; and a capsule biasing mechanism in the chamber; an accumulator assembly connected to an accumulator flow path on a first side of the capsule; a one-way valve coupled to an oil supply path, the oil supply path connected on a second side of the capsule; and a spool valve positioned to intersect the accumulator flow path, wherein the first piston and the second piston are selectively actuated or deactuated by controlling fluid to the chamber, the accumulator assembly, the one-way valve, and the spool valve.

[063] A valvetrain can comprise: an oil control assembly; a rocker arm configured to seat against a first piston; and a pushrod configured to seat against a second piston.

[064] A valvetrain can comprise a pushrod coupled to a roller lifter. [065] A valvetrain can comprise a cylinder head, wherein an oil control assembly is installed in the cylinder head

[066] A valvetrain can comprise a cylinder head and a carrier seated on the cylinder head, and wherein an oil control assembly is installed in the carrier.