This application relates to engine system and component designs to enable variable valve actuation and cylinder control comprising cylinder deactivation and cylinder deactivation with early exhaust valve opening.
It is desired to offer variable valve actuation comprising two or more modes, such as a nominal engine operation mode and a second engine operation mode. The control circuits can be complex and can require multiple engine cycles to switch between the nominal and the second engine operation modes. When oil controlled, the valvetrain can comprise a large number of oil control valves (“OCVs”) such as one per each valve per engine operation mode. This number of OCVs increases size, weight, and complexity of the engine system. Such dual mode operation can also have complexities from overlapping or overlaying one valvetrain component over another.
The methods and devices disclosed herein overcome the above disadvantages and improve the art by way of a rocker shaft that reduces the complexity of the oil control circuit, blocks for mounting oil control valves to the rocker shaft to enable multiple engine operation modes, hydraulic capsules that are configured for hydraulic and mechanical lash adjustment, a rocker arm configuration that is sequenced on the rocker shaft to avoid overlapping the arms of the rocker arms, and an engine system comprising combinations of some or all of the rocker shaft, blocks, capsules, and rocker arms.
Engine systems consistent with the disclosure can comprise a rocker shaft comprising a first cylinder deactivation oil infeed for supplying hydraulic pressure to a first cylinder deactivation oil control valve and a second cylinder deactivation oil control valve in a block. The rocker shaft can comprise first and second cylinder deactivation oil outfeeds, the first cylinder deactivation oil outfeed for connection to the first cylinder deactivation oil control valve and the second cylinder deactivation outfeed for connection to the second cylinder deactivation oil control valve.
The rocker shaft can further comprise a second cylinder deactivation oil infeed for supplying hydraulic pressure to a third cylinder deactivation oil control valve and to an early exhaust valve opening oil control valve in a block. A third oil outfeed can be for connection to the third cylinder deactivation oil control valve. A fourth oil outfeed can be for connection to the early exhaust valve opening oil control valve.
A valvetrain in an engine system can comprise a first, a second, and a third cylinder for combustion. A first, a second, and a third set of intake valves can be respectively paired with the first, second, and third cylinders, each of the first, second, and third sets of intake valves comprising a respective intake rocker arm over a respective intake bridge. Each of the intake rocker arms comprises a hydraulic capsule, and each respective intake bridge is configured to act on its respective set of intake valves. A first, a second, and a third set of exhaust valves can be respectively paired with the first, second, and third cylinders. Each of the first, second, and third sets of exhaust valves can comprise a respective exhaust rocker arm over a respective exhaust bridge. Each of the exhaust rocker arms can comprise a hydraulic capsule. Each respective exhaust bridge can be configured to act on its respective set of exhaust valves. A first, a second, and a third early exhaust valve opening (“EEVO”) rocker arm can be respectively paired with the first, second, and third sets of exhaust bridges, wherein each EEVO rocker arm comprises an EEVO hydraulic capsule.
The engine system and valvetrain can comprise, and the rocker shaft can be combined with, a first block, a first cylinder deactivation oil control valve in the first block, a second cylinder deactivation oil control valve in the first block.
The engine system and valvetrain can comprise, and the rocker shaft can be combined with, a second block, a third cylinder deactivation oil control valve in the second block, and an early exhaust valve opening oil control valve in the second block. A second cylinder deactivation oil infeed can be for supplying hydraulic pressure to the third cylinder deactivation oil control valve and to the early exhaust valve opening oil control valve in a block. A third oil outfeed can be connected to the third cylinder deactivation oil control valve. A fourth oil outfeed can be connected to the early exhaust valve opening oil control valve.
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.
Reference will now be made in detail to the examples which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Directional references such as “left” and “right” are for ease of reference to the figures.
An engine system 10 such as on a Cummins ISX15 engine, can comprise six cylinders 20 and a valvetrain 34 configured for normal operation mode, cylinder deactivation operation mode (“CDA”), and early exhaust valve opening (“EEVO”) to provide variability and controllability at each cylinder. The engine system 10 can operate variably in a combination of cylinder deactivation operation mode and early exhaust valve opening operation mode. With appropriate oil control in combination with a rocker shaft 500, half-engine, full engine, and individual cylinder operation modes can be configured and selected. For example, the engine can be configured for full engine CDA, half engine CDA, or individual cylinder CDA so that any number of the engine cylinders can operate in CDA. Using the disclosed engine system 10, the rockers arms 600, 900 can be arranged line-to-line with no overlap during motion while enabling selective implementation of EEVO on some valves.
Variable valve actuation (VVA) can be accomplished by using combinations of hydraulic capsules, such as a cylinder deactivation capsule 700 and an early exhaust valve opening capsule 800. The hydraulic capsules can have combinations of hydraulic and mechanical lash setting functionality, or one or the other of lash adjustment functionalities. By using other hydraulic capsules, other VVA functionality can be achieved. For example, it is possible to exchange an early exhaust valve closing capsule for the EEVO capsule, or arrange the second hydraulic capsule on the intake valve bridge instead of the exhaust valve bridge so that early intake valve opening or closing is the functioning hydraulic capsule instead of the EEVO capsule.
Such an engine system 10 comprises modifications to enable CDA on all of the intake valves I111-I162 and on all of the exhaust valves E111-E162. Further complementary modifications are needed to enable EEVO on a subset of exhaust valves E111, E121, E131, E141, E151, & E161. A goal is to limit the total amount of hardware while maximizing the functionality. Serviceability and synchronous valve operation are additional goals. Through novel optimizations of the rocker shaft 500, and through new oil control valve mounting blocks 80, 90, the first and third goals can be achieved. The location and orientation of new OCV mounting blocks 80, 90 permit serviceability, as do additional modifications discussed below on the cylinder deactivation capsules (“CDA capsules”) 700 and early exhaust valve opening capsules (“EEVO capsules”) 800.
The engine system 10 is an in-line, 6-cylinder, type III engine. A cam rail 60 spins under the rocker arms 600 & 900. Eccentric cam lobes 61 & 62 are respectively paired with the rocker arms 600 & 900 to press on respective rollers 661, 962. The eccentricities of the respective cam lobes 61 & 62 are selected to time the motion of the rocker arms so that they pivot about the rocker shaft 500 to lift and lower respective intake valves I111-I162 and exhaust valves E111-E162. Intake rocker arms 611, 612, 613, 614, 615, 616 in this example provide only normal operation mode or cylinder deactivation operation mode. However, additional modifications are not excluded to enable additional functionality such as early or late intake valve opening or closing (EIVO, EIVC, LIVO, LIVC). A pair of intake valves 13 is shown in
Two exhaust valves 14 are shown in
It is possible to provide a single oil control valve for enabling CDA for all valves of a cylinder. A single oil control valve can control both intake and exhaust valve CDA functionality. So, in
Advantages of using the single CDA capsule as described can be explained by looking to
The signals in volts and the time in seconds are exemplary only and provided to lend relative relationships to
The need for failsafe and the benefit of predictable synchronous valve operation can be seen in
To implement the novel OCV layout, new CDA OCV block 90 (“first block”) and new EEVO OCV block 80 (“second block”) are shown in
The design of CDA OCV block 90 of
Rocker shaft 500 comprises a CDA outfeed duct 520 parallel to the supply oil feed duct 510. The CDA oil outfeed duct 520 distributes the supply oil from the CDA OCVs to respective intake rocker arms 611, 612, 613. A single CDA outfeed duct 520 can span the length of the rocker shaft 500, leading to simplicity of manufacture. End plugs can seal the ends of the CDA outfeed duct 520. Then, CDA channel dividers 581, 582 can intersect the CDA outfeed duct 520 and additional plugs can divide the CDA outfeed duct 520 into the three CDA hydraulic lines 5201, 5202, 5203. Deactivation and reactivation of all valves of each cylinder can be discretely controlled independent of the other cylinders using this divided CDA outfeed technique.
As shown in the schematic, CDA OCV 1, if seated in opening 91, would receive the supply oil split from CDA oil port 9221 and direct it to CDA output oil port 9271 and CDA oil outfeed 526. Traversing CDA hydraulic line 5201, the supply oil would then exit intake rocker arm port 571 to enter intake rocker arm 611 and act on intake CDA capsule I1 and also exit exhaust rocker arm port 561 to enter exhaust rocker arm 621 and act on exhaust CDA capsule E1.
CDA OCV 2, if seated in opening 92, would receive the supply oil split from CDA oil port 9221 and direct it to CDA output oil port 9261 and CDA oil outfeed 527. Traversing CDA hydraulic line 5202, the supply oil would then exit intake rocker arm port 572 to enter intake rocker arm 612 and act on intake CDA capsule I2 and also exit exhaust rocker arm port 562 to enter exhaust rocker arm 622 and act on exhaust CDA capsule E2.
The EEVO OCV block 80 of
Drop-in openings 84, 85 in upper surface 82 permit ease of assembly & ease of serviceability and receive EEVO OCV in opening 84 and CDA OCV in opening 85. Fastener holes 41, 42 in ledge 83 can accept fasteners 6542, 6541 such as bolts, rivets, screws, or the like to anchor the EEVO OCV block 80 to fastener receiving holes 543, 544 in rocker shaft 500. A coupling rocker face 81 abuts the rocker shaft 500. A gland 86 can be formed in coupling rocker face 81 to receive a seal or sealant to give fluid-tight contact. Also, a fluid notch 87 can be formed with or without the gland 86.
A single inlet oil port 8241 is configured to receive supply oil from rocker shaft supply oil feed duct 510 by way of inlet oil infeed 524. As shown schematically in
Rocker shaft 500 comprises an EEVO outfeed duct 530 parallel to the supply oil feed duct 510 and parallel to the CDA outfeed duct 520. The EEVO outfeed, supply oil feed, and CDA outfeed can each span the rocker shaft with capping or other plugging at end 504. The EEVO oil outfeed duct 530 distributes the supply oil from the EVO OCV to respective exhaust valves via rocker arms 900 and EEVO capsules 801, 802, 803. A single EEVO outfeed duct 530 can span the length of the rocker shaft 500, leading to simplicity of manufacture. End plugs can seal the ends of the EEVO outfeed duct 530. Implementation of early exhaust valve opening operation mode can be implemented on half the cylinders of the engine with the same response time and valve timing using this EEVO outfeed technique.
As shown in the schematic, EEVO OCV A, if seated in opening 84, would receive the supply oil split from inlet oil port 8241 and direct it to EEVO output oil port 8311 and EEVO oil outfeed 531. Traversing EEVO hydraulic line 5301 (part of EEVO outfeed duct 530), the supply oil would then exit the rocker shaft at EEVO rocker arm ports 591, 592, 593 to traverse respective rocker arms 911, 912, 913 and actuate respective EEVO capsules 801, 802, 803.
CDA OCV 3, if seated in opening 85, would receive the supply oil split from inlet oil port 8241 and direct it to CDA output oil port 8281 and CDA oil outfeed 528. Traversing CDA hydraulic line 5203, the supply oil would then exit intake rocker arm port 573 to enter intake rocker arm 613 and act on intake CDA capsule I3 and also exit exhaust rocker arm port 563 to enter exhaust rocker arm 623 and act on exhaust CDA capsule E3.
Each of the OCVs can be of the same internal structure as shown in the schematic OCV circuit of
Alternatively, simple on/off OCVs can be used instead of the dual pressure OCVs. Electromagnetic switching is discussed, but alternatives such as electromechanical switching, among others, can be used.
The rocker shaft 500 is shown for three cylinders of six cylinders, so two rocker shafts can be used in mirror image to one another, as shown in
What can be seen in
Supply oil fed to capsule cup 631 can be contained by interfacing surface of the capsule cup 631 and upper outer body 701 of the CDA capsule. Additional measures can comprise a sealing cap 770, an o-ring in a seat around capsule bottom 757, among other measures. Supply oil traverses leak down paths in middle outer body 756 and capsule cup 631. Supply oil reaches latch groove 755. When low pressure P1 is supplied, the CDA capsule is primed and passively in a latched condition, thereby transferring the full motion of the rocker arm down to stroke the valves open and closed.
When high pressure P2 is supplied, it collapses the latches 722 of the latch assembly 750 and compresses the latch spring 752. The CDA capsule 700 now provides “lost motion” via lost motion springs 740. The capsule collapses, the latch assembly 750 slides up and pushes lash cup 730 up in to upper lash chamber 741 when the rocker arm rocks. The rocker arm motion is not transferred to the valves during this cylinder deactivation mode (CDA). Upon reactivation of the valves, the high pressure P2 is removed as the corresponding CDA OCV valve is returned to a passive state SP. The lost motion springs 740 overcome low fluid pressure P1 and push the lash cup 730 back toward the valves, and the latch assembly re-engages with latches 722 pushed by latch spring 752 back to latch groove 755. Excess oil can traverse bleeds like bleed 732 and bleeds in the lower outer body 733 and e-foot attachment 711 and e-foot 712.
The CDA capsule 700 in the CDA rocker arm 600 can be mechanically set for lash while including a hydraulic lash aspect. The CDA capsule lash can be set mechanically, as by screwing the capsule in place as when interfacing threading on upper outer body 701 and upper capsule cup 630. Threading and mechanical lash setting aspects can alternatively be included in the interface of sealing cap 770 and the upper outer body 701. A shim 760, a snap ring 780, and a lid 790 can contain the lost motion springs 740 within the upper lash chamber 741. A hex or other feature 791 can be included in the lid 790 to effectuate rotation of the CDA capsule within the capsule cup 630. Adjusting the height of the CDA capsule by screwing it in or out sets mechanical lash. Then, a hydraulic internal set-up can provide hydraulic lash to the rocker arm. The low pressure P1 can be selected to provide a baseline pressure in the upper lash chamber for hydraulic lash provisions. The CDA capsule 700 is serviceable. A baseline hydraulic pressure to the capsule can provide for lash while a change in pressure can actuate the spring-loaded latch for facilitating lost motion during CDA. The CDA rocker arm 600 can be used to press on the valve bridge 71 over the intake valves 13 or to press on the valve bridge 72 over the exhaust valves 14.
An EEVO capsule 800 representative of EEVO capsules 801-806 is set in the EEVO rocker arm 900. The EEVO capsule can comprise one or both of a mechanical lash setting aspect and a hydraulic lash setting aspect. A mechanical lash setting aspect can be achieved by manipulating a hex or other coupling 851 in a lid 852. Lid 852 can fit against top cup 821 with a snap ring 860 and a shim 850. Like above, screwing the EEVO capsule up or down can mechanically set lash. A cap 870 can surround top cup 821 and can abut capsule cup 981.
Capsule body can comprise top cup 821, bottom cup 823, shoulder 822, and through-hole 824. Supply oil from pathway 912 reaches through-hole 824. At low pressure P1, the inner cup 830 is spaced from shim 850 and biased by a capsule lost motion spring 840. A frit 831 can extend from the inner cup to space the inner cup 830 with respect to the check 815, push the check down, and restrict the travel of the inner cup. Low pressure oil P1 can enter a lash hat 814 and lash chamber 813. Lash spring 816 can bias lash body 810 and cleat seat 812, and biasing members 74 can oppose. With low pressure oil P1 trapped in lash chamber 813, hydraulic lash can apply, with the check 815 rising to shoulder 822 during rocker arm motion and valve actuation. With high pressure oil P2 supplied to through-hole 824, the capsule lost motion spring force is overcome and the inner cup 830 rises to seat against shim 850 and trap fluid in top cup 821. High pressure expands the compartment 817 formed in bottom cup 823 and pushes lash body 810 out. Early exhaust valve opening can occur with the adjusted size of compartment 817. Using the arrangement, a baseline hydraulic pressure provides lash adjustment. A change in pressure from low pressure P1 to high pressure P2 causes the EEVO rocker arm 900 to open the corresponding exhaust valve earlier than the bridge 72 connected to the CDA rocker arm 600 would open that valve.
Other implementations will be apparent to those skilled in the art from consideration of the specification and practice of the examples disclosed herein.
This is a § 371 National Stage entry of Patent Cooperation Treaty Application No. PCT/EP2019/025043, filed Feb. 14, 2019, which claims the benefit of U.S. provisional application No. 62/631,491, filed Feb. 15, 2018, all of which are incorporated herein by reference and relied upon for the benefit of priority.
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PCT/EP2019/025043 | 2/14/2019 | WO | 00 |
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WO2019/158268 | 8/22/2019 | WO | A |
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