WO2019228671A1

WO2019228671A1 - Primary and auxiliary variable valve actuation valvetrain

Info

Publication number: WO2019228671A1
Application number: PCT/EP2019/025163
Authority: WO
Inventors: Matthew A. Vance; Mark VANWINGERDEN; Andrew Lee
Original assignee: Eaton Intelligent Power Limited
Priority date: 2018-05-31
Filing date: 2019-05-30
Publication date: 2019-12-05

Abstract

A valvetrain system for primary mode and auxiliary mode variable valve actuation, comprising a primary rocker arm, a rotatable cam shaft, a valve bridge, and a switchable capsule. The rotatable cam shaft is configured for variably transferring forces directly or indirectly to the primary rocker arm to rock the primary rocker arm according to a primary mode valve actuation profile. The valve bridge comprises a primary arm comprising a primary valve mounting area and a pass- through. An auxiliary valve mount is configured to transfer an auxiliary mode valve actuation profile through the pass-through. A switchable capsule comprises a movable element. The movable element is switchable between an extended position and a collapsed position. The switchable capsule is configured to actuate on the auxiliary valve mount to impart the auxiliary mode valve actuation profile to the auxiliary valve when the movable element is in the extended position.

Description

PRIMARY AND AUXILIARY VARIABLE VALVE ACTUATION VALVETRAIN

Field

[001] This application provides variable valve actuation in a valvetrain for a primary mode valve actuation profile and for an auxiliary mode valve actuation profile. Techniques such as bleeder braking, two stroke braking, intake valve braking, early exhaust valve opening, and late intake valve closing can be

accomplished via the auxiliary mode valve actuation profile. The valvetrain can further provide deactivation options and hydraulic lash adjustment in a compact footprint.

Background

[002] It is desirable to offer better fuel economy and auxiliary or emergency engine braking techniques. However, it is difficult to arrange a valvetrain within the customer packaging requirements and offer a variety of fuel economy options and braking techniques.

SUMMARY

[003] The methods, devices, and systems disclosed herein overcome the above disadvantages and improves the art by way of a valvetrain system for primary mode and auxiliary mode variable valve actuation, comprising a primary rocker arm, a rotatable cam shaft, a valve bridge, and a switchable capsule. The primary rocker arm comprises a primary receiving end, a primary transfer end, and a primary pivot therebetween. The rotatable cam shaft comprises a cam configured for variably transferring forces directly or indirectly to the primary receiving end of the primary rocker arm to rock the primary rocker arm about the primary pivot according to a primary mode valve actuation profile. The valve bridge is coupled to the primary transfer end of the primary rocker arm and is configured to receive transferred forces and to couple the transferred forces to a primary valve and to an auxiliary valve. The primary valve and the auxiliary valve are configured to lift and to lower over an engine cylinder. The valve bridge comprises a primary arm comprising a primary valve mounting area on a primary end of the primary arm, and a pass- through on an auxiliary end of the primary arm. An auxiliary valve mount is configured to transfer an auxiliary mode valve actuation profile through the pass- through. A switchable capsule comprises a movable element. The movable element is switchable between an extended position and a collapsed position. The switchable capsule is configured to actuate on the auxiliary valve mount to impart the auxiliary mode valve actuation profile to the auxiliary valve when the movable element is in the extended position.

[004] Methods of actuating the valvetrain system can comprise extending the movable element to impart to the auxiliary valve a two stroke braking profile as the auxiliary mode valve actuation profile, and actuating the second switchable capsule to impart on the auxiliary intake valve a two stroke braking profile as the auxiliary mode intake valve actuation profile.

[005] Another method of actuating the valvetrain system can comprise extending the movable element to impart to the auxiliary valve one of a bleeder brake profile, a compression release brake profile, an early exhaust valve opening profile, or a late intake valve closing profile as the auxiliary mode valve actuation profile, and rotating the cam shaft to impart a primary mode valve actuation profile to the primary valve.

[006] Additional methods can comprise actuating a variable geometry turbocharger connected to an exhaust system, the exhaust system fluidly connected to the auxiliary valve, to thereby adjust the back pressure in the valvetrain system and adjust the braking power provided by the auxiliary valve. Using a variable geometry turbocharger (VGT) capable of variable restriction of the exhaust flow from the exhaust manifold with the disclosed valvetrain system alternatives provides a mechanism to further modulate the power of the engine braking systems disclosed herein.

[007] The systems and methods can be combined with cylinder deactivation devices and techniques.

[008] 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. BRIEF DESCRIPTION OF THE DRAWINGS

[009] Figure 1 is a simplified view of a valvetrain system comprising a primary exhaust rocker arm, a primary intake rocker arm, an auxiliary exhaust rocker arm, and an auxiliary intake rocker arm.

[010] Figure 2 is a view of a type V primary rocker arm and an auxiliary mode cam-actuated auxiliary switchable capsule.

[011] Figure 3 is a view of a type III primary rocker arm and an auxiliary mode cam-actuated auxiliary switchable capsule.

[012] Figure 4 is a view of a type V primary rocker arm and a type III auxiliary rocker arm.

[013] Figure 5 is a view of a type III primary rocker arm and a type III auxiliary rocker arm.

[014] Figures 6A and 6B provide examples of a collapsed position and an extended position for a switchable capsule.

[015] Figure 7 provides an example of a valve bridge.

[016] Figure 8 provides an example of a decompression engine braking valve lift profile as an auxiliary mode valve actuation profile.

[017] Figure 9 provides an example of a 2-stroke engine braking valve lift profile.

[018] Figures 10 & 11 are views type V primary rocker arms and direct- acting switchable capsules.

[019] Figure 12 is an example of hydraulically lashed valvetrain system for bleeder braking, cylinder deactivation, and intake duplication.

[020] Figures 13A-13C are alternative valve lift profiles.

[021] Figure 14 provides exemplary combinations of primary and auxiliary intake valves and exhaust valves.

DETAILED DESCRIPTION

[022] Reference will now be made in detail to the examples which are illustrated in the accompanying drawings. Directional references such as“left” and “right” are for ease of reference to the figures. Some examples apply a primary mode valve actuation profile and an auxiliary mode valve actuation profile to exhaust valves of a valvetrain, and other examples apply a primary mode valve actuation profile and an auxiliary mode valve actuation profile to intake valves of a valvetrain. The lift profiles are exemplary and explanatory. Nothing precludes using a valve actuation technique on and exhaust valve that was taught on an intake valve and vice versa when applying the principles of primary and auxiliary modes of valve actuation. While some examples comprise lift heights or rotation angles, it is to be understood that these are examples and other lift heights and rotation angles can be used without departing from the teachings of the disclosure.

[023] A valvetrain system using an auxiliary cam for added motion actuation (Variable Valve Actuation, or WA) is disclosed. Included is engine braking, 2-stroke engine braking, Early Exhaust Valve Opening (EEVO), & Late Intake Valve Closing (LIVC). Additionally, deactivation and lost motion devices can be added to enable deactivation of a valve for techniques such as cylinder deactivation or for techniques that complement the auxiliary can added motion actuation. Hydraulic lash

adjustment can be packaged as well. The disclosure provides a way to add WA function to an existing engine with limited changes to existing valvetrain.

[024] The figures show various valvetrain systems for primary mode and auxiliary mode variable valve actuation. In a first example in Figure 1 , a simplified view of a valvetrain system comprises a type III primary exhaust rocker arm 350, a type III primary intake rocker arm 300, an type III auxiliary exhaust rocker arm 150, and a type III auxiliary intake rocker arm 100. The valvetrain system actuates exhaust valves E1 , E2 and intake valves 11 , I2 to open and close fluid flow access points to a cylinder C1. A fuel injector FI is shown schematically.

[025] The primary intake and exhaust rocker arms 300, 350 are similar in functionality in this example, but differ in shape to accommodate their position with respect to the primary intake valve 11 and primary exhaust valve E1. Likewise, the auxiliary intake and exhaust rocker arms 100, 150 are similar in functionality, but differ in shape to accommodate their position with respect to auxiliary intake valve I2 and auxiliary exhaust valve E2.

[026] The valvetrain system of Figure 1 is explained in more detail in Figure 5 with respect to the exhaust valves E1 , E2. A primary cam shaft 30 is rotatable to impart a profile from a cam lobe. Cam lobe is typically an eccentrically shaped formation on the primary cam shaft 30. The figures simplify the cam shaft and integrated cam lobes as circles, but cam lobes can have a variety of shapes to impart a lift profile to the valves to which they are coupled. It is possible to have more than one lift profile on a cam, such as when imparting more than one valve lift profile to a particular valve, such as 2-stroke engine braking or such as brake gas recirculation or a combination thereof. Cam shaft 30 rotates to transfer forces directly to the primary exhaust rocker arm 350.

[027] The primary exhaust rocker arm 350 comprises rocker arm body 351 comprising a primary receiving end 358, a primary transfer end 356, and a primary pivot about a rocker shaft 40 therebetween. Primary receiving end comprises a roller 353 for rotating against the cam of camshaft 30. The rotatable cam shaft and cam variably transfer forces directly to the primary receiving end 358 of the primary exhaust rocker arm 350 to rock the primary exhaust rocker arm about the primary pivot according to a primary mode valve actuation profile imparted by the shape of the cam. When the primary exhaust rocker arm 350 rocks, it pivots the primary transfer end 356 towards a valve bridge 700. A capsule 352 such as a mechanical lash device, a hydraulic lash device, a deactivating capsule, among others, can be included in the primary transfer end 356. An elephant foot (e-foot) 354 is shown schematically and can comprise any number of coupling structures so that primary transfer end 356 can transfer forces for the primary mode valve actuation profile to the valve bridge, so long as the primary rocker arm or one of its subcomponents is not deactivated in a lost motion mode that would prevent transfer of forces to the valve bridge 700.

[028] The valve bridge 700 is coupled to the primary transfer end 356 of the primary exhaust rocker arm 350 and is configured to receive the transferred forces from the cam and to couple the transferred forces to a primary exhaust valve E1 and to an auxiliary exhaust valve E2. An auxiliary mode valve actuation profile can be added to the forces applied to the auxiliary exhaust valve E2. Or, the auxiliary mode valve actuation profile can be the only force applied to the auxiliary exhaust valve E2 when the primary exhaust rocker arm 350 or one of its subcomponents, such as capsule 352, is in a deactivation mode.

[029] The primary exhaust valve E1 and the auxiliary exhaust valve E2 are configured to lift and to lower over an engine cylinder C1. The valve bridge 700 can comprise a primary arm 701 comprising a primary valve mounting area 705 on a primary end of the primary arm, and a pass-through 725 on an auxiliary end of the primary arm. The primary arm can be forked 710, 711 at the auxiliary end to flank the auxiliary valve mount 720. The auxiliary valve mount 720 can comprise a cavity 751 for housing a swiveling elephant-foot 760. Cavity 751 can be formed by walls 721 configured with mounting places 724 for receiving an e-foot axle 740. The e- foot axle 740 can abut forks 710, 711 as stop-motion features. A main surface of auxiliary valve mount 720 can be acted on by a switchable capsule 152 to pivot the auxiliary valve mount 720 about a pivot axle 730 spanning mounting points 723, 730 in the forked primary arm. Auxiliary valve mount 720 is configured to transfer an auxiliary mode valve actuation profile through the pass-through 725. Numerous valve bridge alternatives are known in the art for actuating multiple valves from a single bridge, including non-pivoting auxiliary valve mount types, guided valve bridges, non-guided valve bridges, among others. Example alternative valve bridges include those described in US design patent D839,310 and US pregran publication US2017/0276034.

[030] A switchable capsule 102, 152 comprises a movable element 625 that can reciprocate in a cylinder 602. The movable element 625 is switchable between an extended position in Figure 6B and a collapsed position in Figure 6A as by controlled hydraulic pressure HP and thus the switchable capsule constitutes a deactivatable hydraulic device. No hydraulic pressure HP is applied in Figure 6A, as indicated by the X, so the movable element 625 can be a plunger collapsed in a cylinder 602 within body 600. Plunger can be stepped and secured within cylinder 602 by a snap ring 626 or the like. A fluid control device comprising a ball 623 in a cage 621 can be seated in a plunger cup 620 in the cylinder 602. An upper cylinder 601 can house a cup 616 of a pintle 615. Pintle 615 can be biased by a pintle spring 618 biased against a disc 611. Disc can be secured by such as another snap ring 612 and cap 613. Disc 611 can be adjustable. Without hydraulic pressure HP, the pin 617 of pintle 615 pushes ball 623 away from a shoulder in the body 600. But when hydraulic pressure is applied, the pintle 615 rises in the upper cylinder 601 , the ball 623 can be pushed by spring 622 against shoulder, and hydraulic fluid can be captured in plunger cup 620. The hydraulic fluid can be supplied through cross drilled ports 630, 640 into chamber 650, and then the hydraulic fluid can fill plunger cup 620 and extend the plunger (movable element 625) until the ball 623 reaches the shoulder. The trapped hydraulic pressure permits auxiliary valve actuation while the hydraulic pressure HP is applied. The hydraulic pressure HP can be supplied through a tower or the cylinder block in the case of direct-acting switchable capsules of Figures 2, 3, & 10-12 or through the rocker arm in the case of Figures 4 & 5. The switchable capsule is configured to actuate on the auxiliary valve mount 720 to impart the auxiliary mode valve actuation profile to the auxiliary exhaust valve E2 when the movable element 625 is in the extended position (Figure 6B).

[031] Alternative switchable capsules comprise alternative hydraulic devices 800, 810, 820, among others, and can alternatively comprise castellation devices, magnetic devices, electromagnetic devices, and piezoelectric devices.

[032] Switchable capsules can be mounted in a tower or the cylinder block in the case of the switchable capsules of Figures 2, 3, & 10-12. An auxiliary mode valve actuation profile can be imparted by extending a collapsing the movable element 625. But, it is also possible to provide additional transfer forces through a rotatable overhead cam 70 configured act on the switchable capsule. The overhead cam 70 can impart, for example, brake motion or another VVA valve lift profile.

[033] Returning to Figures 1 & 5, the valvetrain system can further comprise an auxiliary exhaust rocker arm 150 on an opposite side of the engine cylinder C1 from the primary exhaust rocker arm 350. The auxiliary exhaust rocker arm comprises a rocker arm body 151 comprising an auxiliary receiving end seating an auxiliary roller 156, an auxiliary transfer end for seating the switchable capsule 152, and an auxiliary pivot about a rocker shaft 50 therebetween. An auxiliary rotatable cam shaft 60 comprises an auxiliary cam configured for variably transferring forces directly to the roller 156 on the auxiliary receiving end of the auxiliary exhaust rocker arm 150 to rock the auxiliary exhaust rocker arm 150 about the auxiliary pivot according to the auxiliary mode valve actuation profile. The switchable capsule 152 mounted to the auxiliary transfer end can receive hydraulic fluid through the rocker arm body 151 and through the rocker shaft 50, of the switchable capsule 152 can receive hydraulic fluid from a source external to the rocker arm body 151 , or as above, the switchable capsule 152 can be an alternative hydraulic device or one of the enumerated non-hydraulic devices.

[034] The switchable capsule 152 can convey a force F1 from the transfer end of the auxiliary exhaust rocker arm to the auxiliary valve mount. Auxiliary valve mount 720 can move and transfer force F2 to the auxiliary exhaust valve E2. The valve bridge can pivot and supply a return force F3 to the primary exhaust rocker arm 350 that is beneficial for maintaining hydraulic lash when a hydraulic lash adjuster is used in the valvetrain system. Valve stem spring seats EE1 , EE2 are shown seating valve stem springs ES1 , ES2 so that the exhaust valves can lift and lower as is known in the art. Depending on the timing of the application of the force F1 , the auxiliary exhaust valve E2 can move a different amount than the primary exhaust valve E1. A gap G1 between the tops of the valve stem spring seats EE1 , EE2 is illustrated in the Figures and signifies the lift height difference between the primary exhaust valve E1 and the auxiliary exhaust valve E2. The gap G1 can correspond to the extension of the plunger (movable element 620).

[035] Figure 1 shows a second primary rocker arm in the form of an primary intake rocker arm 300. A second primary cam can be mounted to the rotatable cam shaft 30 to impart a primary mode intake valve actuation profile a primary intake valve 11 and an auxiliary intake valve I2. A capsule 302 like capsule 352 can be mounted to a transfer end of the primary intake rocker arm 300 and a roller 303 can be mounted to a receiving end to receive transfer forces from the cam on the cam shaft 30. Primary intake rocker arm 300 can share rocker shaft 40 with the primary exhaust rocker arm 350. A second valve bridge can receive transfer forces from an e-foot affiliated with capsule 302 among other options. A second switchable capsule 102 can be arranged on an intake side of the engine cylinder C1 for actuating for selectively imparting a second auxiliary mode intake valve actuation profile.

[036] A second auxiliary rocker arm in the form of an auxiliary intake rocker arm 100 can be opposite the primary intake rocker arm 300 on an opposite side of the engine cylinder from the second primary rocker arm. The cylinder C1 can be divided thereby into a primary rocker arm side 10 and an auxiliary rocker arm side 20 (or auxiliary switchable device side as per the non-auxiliary rocker arm

alternatives). The second auxiliary rocker arm can comprise a second auxiliary receiving end, a second auxiliary transfer end, and a second auxiliary pivot on the auxiliary rocker shaft 50. A second auxiliary cam can be mounted to the auxiliary cam shaft 60. The second auxiliary cam can be configured for variably transferring second forces directly to the second auxiliary receiving end and roller 106 of the second auxiliary rocker arm 100 to rock the second auxiliary rocker arm 100 about the second auxiliary pivot on the rocker shaft 50 according to the second auxiliary mode valve actuation profile. The second switchable capsule 102 can be mounted to the second auxiliary transfer end.

[037] Figure 3 is a view of a type III primary rocker arm 350 and an auxiliary mode cam-actuated auxiliary switchable capsule 152, aspects of which were explained above.

[038] Figure 4 is a view of a type V primary rocker arm 500 and a type III auxiliary rocker arm 151 , aspects of which were explained above.

[039] Numerous direct-acting and rocker arm combinations can be achieved. Figure 2 is a view of a type V primary rocker arm 500 and an auxiliary mode cam-actuated auxiliary switchable capsule 152. The rotatable cam shaft 80 indirectly acts of the primary rocker arm 500. The rotatable cam shaft 80 is intervened by a primary lifter 900 and a primary push tube 90. Primary lifter 900 can comprise a roller lifter, a tappet, a combination device, among others. The primary push tube 90 couples to the primary receiving end 508 to transfer forces from the primary lifter 90 and the primary cam on the cam shaft 80. A push tube mount 590 can be included in the primary receiving end 508. The transfer forces cause the primary rocker arm to pivot about rocker shaft 70 and the primary transfer end 506 can transfer forces to the e-foot 504, to the valve bridge 700. Switchable capsule 152 can act as above and with overhead cam 70 as above.

[040] Figures 10 & 11 are views of type V primary rocker arms and direct- acting switchable capsules. Figure 10 shows an alternative primary lifter 901 as an example of a combination device comprising a hydraulic lash adjuster 910 and a deactivating lost motion capsule 920 over a roller 930.

[041] Figure 11 shows the primary rocker arm is configured to switch between a primary lost motion configuration and a primary full motion configuration. If the cam side arm 511 is latched against the valve side arm 512, transfer forces from the cam 80, lifter 900, push tube 90, and receiving end 518 reach transfer end 516. E-foot 514 and valve bridge 700 move and so too the primary and auxiliary exhaust valves E1 , E2 can move according to the primary mode valve actuation profile. If the cam side arm 511 is not latched against the valve side arm 512, there can be pivoting about the rocker shaft 70, but the transfer forces act on lost motion spring 513 and the e-foot does not move the valve bridge 700 against the primary and auxiliary exhaust valves E1 , E2. [042] Figure 12 is an example of a hydraulically lashed valvetrain system for bleeder braking, cylinder deactivation, and intake duplication. Figure 12 combines aspects of Figure 11 , including the type V lost motion primary rocker arm 510 and direct acting switchable capsule 152, with a hydraulic control network on the intake valve side. In a primary mode, the cam on camshaft 80 can supply transfer forces to the primary and auxiliary exhaust valves so that they follow the normal lift primary mode valve actuation profile of Figure 13A. The normal lift primary mode valve actuation profile can also be seen in the solid exhaust (drive) line in Figure 9. The deactivating type V lost motion primary rocker arm 510 can also be controlled to deactivate transfer of forces from the cam on camshaft 80 to the primary exhaust valve E1 and auxiliary exhaust valve E2. So, primary exhaust valve E1 can be closed, thus supplying the deactivated auxiliary mode valve actuation profile of Figure 13C. This would eliminate the normal lift primary exhaust mode valve actuation profile seen on the solid exhaust (drive) line in Figure 9. The switchable capsule 152 can be actuated to provide bleeder braking on the auxiliary exhaust valve E2. Auxiliary exhaust valve can be held open by the movable element 625, thus supplying the bleeder braking auxiliary mode valve actuation profile shown by the dashed line of Figure 13B. Such a bleeder brake device is capable of holding the auxiliary exhaust valve open during an entire stroke (i.e. intake, compression, expansion, exhaust).

[043] Or, the movable element 625 can be controlled to collapse and extend in correlation to a lift and lowering pattern of a piston within the cylinder C1. Now, with control of the switchable element, a sophisticated auxiliary mode valve actuation profile can be applied to the auxiliary exhaust valve E2 according to the dashed exhaust (brake) line in Figure 9.

[044] Figure 9 shows degrees of crankshaft revolutions along the X-axis.

The piston that compresses gasses in the combustion chamber lifts and lowers in synchrony with the crankshaft. Portions of six strokes of the piston are shown as it drops from bottom dead center to top dead center in Figure 9. Exemplary valve lift heights are shown on the Y-axis, though the numbers are non-limiting examples. Two compression release engine braking events can occur near the piston top dead center at around 250 and 430 degrees of crankshaft revolution. To give these compression release engine braking events more braking power, the switchable capsule is actuated to cause auxiliary exhaust valve lift at approximately 170 and 330 degrees of crankshaft revolution. These auxiliary exhaust valve lifts provide brake gas recirculation. The braking power can be further tailored by opening and closing a variable geometry turbocharger (VGT) downstream from the exhaust valves. Closing the VGT increases the brake power by created a restricted opening against the exhaust stream. Opening the VGT lessens the restriction to exhaust stream flow. The switchable capsule arrangements disclosed herein improve over other bleeder braking and auxiliary exhaust valve control techniques by providing an active, controllable duration mechanism for when to open and close the auxiliary exhaust valve. The braking power and braking event is more predictable and can be more powerful for stopping the vehicle due to the increased number of times that braking can be imparted per crankshaft revolution.

[045] Even more sophisticated, the intake valves also comprise a primary intake rocker arm, a valve bridge, and a hydraulic device over the valve bridge. The primary intake rocker arm can provide the normal lift primary mode valve actuation profile can also be seen in the dotted intake (drive) line in Figure 9. This, too, can be deactivated as by using a deactivating type V lost motion primary intake rocker arm 520.

[046] Primary intake rocker arm 520 is configured to switch between a primary lost motion configuration and a primary full motion configuration. If the cam side arm 515 is latched against the valve side arm 522, transfer forces from the intake cam 90, intake lifter 900, intake push tube 90, and receiving end 528 reach transfer end 526. E-foot 514 and valve bridge 700 move and so too the primary and auxiliary intake valves 11 , I2 can move according to the primary mode valve actuation profile. If the cam side arm 525 is not latched against the valve side arm 522, there can be pivoting about the rocker shaft 72, but the transfer forces act on lost motion spring 523 and the e-foot 524 does not move the valve bridge 700 against the primary and auxiliary intake valves 11 , I2.

[047] Alternative to the lost motion configuration of the deactivating type V lost motion primary intake rocker arm 520, the auxiliary lifter can comprise a deactivating lost motion capsule and, if desired, a hydraulic lash adjuster.

[048] The primary intake valve 11 can be deactivated so that it does not follow the primary mode valve actuation profile. But, the auxiliary intake valve I2 can be controlled by a hydraulic device to open and close to contribute to the braking events. This can be seen in Figure 9 around 130 and 290 degrees of crankshaft revolution when the intake (brake) lift profiles appear. Double braking power can be provided at cruising speeds using the technique of Figure 9.

[049] The valvetrain system of Figure 12 can be used to implement the technique of Figure 9. When the intake primary cam shaft 90 rotates, it lifts the receiving end 528 to press mounting 592 upon a primary piston 802 in a cylinder 801 of a primary hydraulic device. Hyd raulic fluid is squeezed out of cylinder 801 and along path 1 to control valve 1000. When the control valve 1000 permits, the squeeze hydraulic fluid can enter and return from accumulator 890 along path 5. Accumulator 890 can comprise, for example, a biasing member 893 acting on a pressure plate 892 to collect or expel hydraulic fluid in cylinder 891. Control valve 1000 can be controlled to permit squeezed fluid to traverse paths 2, 3, & 4. Then hydraulic device 810 can extend a plunger 812 from a cylinder 811 to actuate auxiliary valve mount 720 and auxiliary intake valve I2. The intake valve control technique can be extended to other auxiliary intake valves on other cylinders as by duplicating the hydraulic device 810 to the hydraulic device 820 with plunger 822 and cylinder 821. Hyd raulic device 820 can be connected by path 3, 2, & 4. The intake valve braking can be implemented thereby. The valvetrain system is capable of duplicating intake lift on one or more intake valves and the valvetrain can provide lift during the usual expansion portion of the stroke.

[050] Figure 8 provides an example of a decompression engine braking valve lift profile as an auxiliary mode valve actuation profile. The technique in Figure 8 is less complicated than that of Figure 9, but does comprise brake gas

recirculation around 160 degrees of crankshaft revolution. An additional opening of one of the exhaust valves, in this case a preliminary opening of the auxiliary exhaust valve E2, permits ingress of air while the piston is at or near bottom dead center.

The additional air is compressed during the compression stroke (braking stroke) of the piston to increase the pressure in the cylinder. A compression release braking event near when the piston is at or near top dead center provides increased braking power due to the increased pressure on the fluid within the cylinder. The added motion of the compression release event and the braking event can be on a dedicated cam such as on cam shaft 60 or 70 or on a separate control line to the switchable capsule 102, 152 or alternative device.

[051] In Figure 8, it is possible to use the primary exhaust mode valve actuation profile on the primary exhaust valve E1 as shown by the solid exhaust (drive) line. Both primary and auxiliary intake valves can follow the primary intake mode valve actuation profile as shown by the dash-dot line Intake in Figure 8.

[052] By way of examples, Figure 14 provides additional combinations of primary and auxiliary exhaust mode valve actuation profiles and primary and auxiliary intake mode valve actuation profiles. Additional combinations can be implemented using the teachings herein.

[053] The disclosure provides mechanisms used for compression release braking, 2 stroke braking, or other WA functions. The mechanisms can comprise a primary rocker arm side 10 and an auxiliary rocker arm side 20. Methods for imparting additional valve motion (added motion) using an auxiliary cam shaft 60, 70 can be achieved. An auxiliary cam shaft 60, 70 can impart motion to one or more of the intake and exhaust valves through a deactivating aspect of the auxiliary rocker arm side 20. This could alternatively be cam shifting. This auxiliary input can be normally deactivated. The auxiliary rocker arm side 20 can be combined with a deactivating system on the primary rocker arm side 10. The auxiliary rocker arm side 20 can be compatible with hydraulic lash adjusting through the use of a balanced bridge.

[054] The auxiliary rocker arm side 20 can be Type I (direct acting) or type III. The primary rocker arm side 10 can be Type III with a single overhead cam over the engine block, or the primary rocker arm side 10 can be Type V.

[055] The auxiliary rocker arm side 20 can be integrated into the cylinder head, or can be a self-contained“bolt on” system installed after the primary rocker arm side 10.

[056] Primary and auxiliary mode valve actuation profiles can be deactivated to switch between VVA modes.

[057] Alternative deactivation methods for switching the primary rocker arm side 10 can comprise:

• For Type III rocker arms: a deactivating capsule combined with, for example, one of the e-foot 354 or capsule 352; Cam shifting; Capsule mounted to the primary rocker arm; Deactivating rocker arm; or Deactivating bridge.

• For Type V rocker arms: a deactivating lifter; a deactivating push tube; a deactivating pivot; a capsule mounted to the primary rocker arm; a deactivating bridge.

[058] Alternative deactivation methods for the auxiliary rocker arm side 20 can comprise: cam deactivation methods; Type I cam actuation; cam shifting; direct acting capsule.

[059] Alternative rocker arms can comprise a Type II rocker arm, and alternative deactivation methods can comprise cam shifting; switching roller finger follower (SRFF) techniques; and use of a deactivating pivot.

[060] Methods of actuating the valvetrain system can comprise extending the movable element to impart to the auxiliary valve a two stroke braking profile as the auxiliary mode valve actuation profile, and actuating the second switchable capsule to impart on the auxiliary intake valve a two stroke braking profile as the auxiliary mode intake valve actuation profile.

[061] Another method of actuating the valvetrain system can comprise extending the movable element to impart to the auxiliary valve one of a bleeder brake profile, a compression release brake profile, an early exhaust valve opening profile, or a late intake valve closing profile as the auxiliary mode valve actuation profile, and rotating the cam shaft to impart a primary mode valve actuation profile to the primary valve.

[062] Additional methods can comprise actuating a variable geometry turbocharger connected to an exhaust system, the exhaust system fluidly connected to the auxiliary valve, to thereby adjust the back pressure in the valvetrain system and adjust the braking power provided by the auxiliary valve.

[063] The systems and methods can be combined with cylinder deactivation devices and techniques.

[064] In an alternative aspect, cylinder deactivation (CDA) can be performed with a Bleeder Brake and variable geometry turbocharger. A method for engine braking using various combinations of cylinder deactivation (CDA), a bleeder brake, and a variable geometry turbocharger (VGT) can be implemented. This provides engine braking retarding function for a diesel engine. [065] Table 1 shows examples of which primary rocker arm side 10 rocker arms can be combined with which auxiliary rocker arm side 20 rocker arms to accomplish example auxiliary mode valve actuation profiles. Table 1

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

Claims

WHAT IS CLAIMED IS:

1. A valvetrain system for primary mode and auxiliary mode valve actuation, comprising:

a primary rocker arm comprising a primary receiving end, a primary transfer end, and a primary pivot therebetween;

a rotatable cam shaft comprising a cam configured for variably transferring forces directly or indirectly to the primary receiving end of the primary rocker arm to rock the primary rocker arm about the primary pivot according to a primary mode valve actuation profile;

a valve bridge coupled to the primary transfer end of the primary rocker arm and configured to receive transferred forces and to couple the transferred forces to a primary valve and to an auxiliary valve, the primary valve and the auxiliary valve configured to lift and to lower over an engine cylinder, the valve bridge comprising:

a primary arm comprising a primary valve mounting area on a primary end of the primary arm, and a pass-through on an auxiliary end of the primary arm; and

an auxiliary valve mount configured to transfer an auxiliary mode valve actuation profile through the pass-through; and

a switchable capsule comprising a movable element, the movable element switchable between an extended position and a collapsed position, the switchable capsule configured to actuate on the auxiliary valve mount to impart the auxiliary mode valve actuation profile to the auxiliary valve when the movable element is in the extended position.

2. The valvetrain system of claim 1 , wherein the switchable capsule is a deactivatable hydraulic device comprising:

a cylinder; and

a reciprocating plunger as the movable element.

3. The valvetrain system of claim 1 , wherein the switchable capsule is one of a castellation device, a magnetic device, an electromagnetic device, and a

piezoelectric device.

4. The valvetrain system of one of claims 1 -3, further comprising a rotatable overhead cam configured to act on the switchable capsule.

5. The valvetrain system of claim 1 , further comprising an auxiliary rocker arm on an opposite side of the engine cylinder from the primary rocker arm, wherein the auxiliary rocker arm comprises:

an auxiliary receiving end, an auxiliary transfer end, and an auxiliary pivot therebetween;

an auxiliary rotatable cam shaft comprising an auxiliary cam configured for variably transferring forces directly or indirectly to the auxiliary receiving end of the auxiliary rocker arm to rock the auxiliary rocker arm about the auxiliary pivot according to the auxiliary mode valve actuation profile; and the switchable capsule mounted to the auxiliary transfer end.

6. The valvetrain system of claim 5, further comprising an auxiliary lifter and an auxiliary push tube, wherein the auxiliary push tube couples to the auxiliary receiving end to transfer forces from the auxiliary lifter and the auxiliary cam.

7. The valvetrain system of claim 6, wherein the auxiliary lifter comprises one or both of a hydraulic lash adjuster and a deactivating lost motion capsule.

8. The valvetrain system of one of claims 5-7, wherein the auxiliary rocker arm is configured to switch between an auxiliary lost motion configuration and an auxiliary full motion configuration.

9. The valvetrain system of claim 1 , further comprising a primary lifter and a primary push tube, wherein the primary push tube couples to the primary receiving end to transfer forces from the primary lifter and the primary cam.

10. The valvetrain system of claim 9, wherein the primary lifter comprises one or both of a hydraulic lash adjuster and a deactivating lost motion capsule.

11. The valvetrain system of one of claims 1 , 9, or 10, wherein the primary rocker arm is configured to switch between a primary lost motion configuration and a primary full motion configuration.

12. The valvetrain system of claim 1 , further comprising:

the primary rocker arm, the rotatable cam shaft, the valve bridge, and the switchable capsule arranged on an exhaust side of the engine cylinder, wherein the primary valve and the auxiliary valve are a primary exhaust valve and an auxiliary exhaust valve, respectively;

a second primary rocker arm, a second primary cam mounted to the rotatable cam shaft, a second valve bridge, and a second switchable capsule arranged on an intake side of the engine cylinder for actuating a primary intake valve and an auxiliary intake valve according to a primary mode intake valve actuation profile and for actuating the second switchable capsule for selectively imparting a second auxiliary mode intake valve actuation profile.

13. The valvetrain system of claim 12, further comprising a second auxiliary rocker arm on an opposite side of the engine cylinder from the second primary rocker arm, wherein the second auxiliary rocker arm comprises:

a second auxiliary receiving end, a second auxiliary transfer end, and a

second auxiliary pivot therebetween;

a second auxiliary cam mounted to the auxiliary cam shaft, the second

auxiliary cam configured for variably transferring second forces directly or indirectly to the second auxiliary receiving end of the second auxiliary rocker arm to rock the second auxiliary rocker arm about the second auxiliary pivot according to the second auxiliary mode valve actuation profile; and

the second switchable capsule mounted to the second auxiliary transfer end.

14. A method of actuating the valvetrain system of claim 12, comprising:

extending the movable element to impart to the auxiliary valve a two stroke braking profile as the auxiliary mode valve actuation profile; and actuating the second switchable capsule to impart on the auxiliary intake valve a two stroke braking profile as the auxiliary mode intake valve actuation profile.

15. A method of actuating the valvetrain system of claim 1 , comprising:

extending the movable element to impart to the auxiliary valve one of a

bleeder brake profile, a compression release brake profile, an early exhaust valve opening profile, or a late intake valve closing profile as the auxiliary mode valve actuation profile; and

rotating the cam shaft to impart a primary mode valve actuation profile to the primary valve.

16. The method of claim 14 or 15, further comprising actuating a variable geometry turbocharger connected to an exhaust system, the exhaust system fluidly connected to the auxiliary valve, to thereby adjust the back pressure in the valvetrain system and adjust the braking power provided by the auxiliary valve.