Title of Invention

AN APPARATUS FOR AN ENGINE ASSEMBLY FOR HYDRAULICALLY CONTROLLING ENGINE VALVE LIFT AT MULTIPLE CYLINDERS

Abstract A single hydraulic circuit module is provided for controlling valve lift at multiple cylinders in an engine. The single module includes a housing that at least partially forms a supply passage and a control passage. The supply passage is in fluid communication with the fluid supply and the control passage is in fluid communication with the feed passage. At least one solenoid valve is provided and supported by the housing positioned between the supply passage and the control passage. The solenoid valve is controllable to vary fluid flow from the supply passage to the control passage to permit adjustment of hydraulic lift assemblies to vary lift of engine valves in response to control of the solenoid valve.
Full Text GP-307652
1
SINGLE HYDRAULIC CIRCUIT MODULE FOR DUAL LIFT
OF MULTIPLE ENGINE VALVES
TECHNICAL FIELD
[0001] The present invention relates to a single hydraulic circuit module
attachable to a cylinder head of an engine for hydraulically controlling engine valve
lift at multiple cylinders.
BACKGROUND OF THE INVENTION
[0002] Engine valve actuator assemblies for engines such as an internal
combustion engine on a motor vehicle typically have a roller finger follower that
contacts an engine valve and is pivotable in response to cam motion to lift the valve.
A typical roller finger follower can be replaced by a hydraulically controlled
switchable roller finger follower ("SRFF"). A hydraulically controlled SRFF, which
is also referred to herein as a hydraulic lift assembly, can provide two distinct engine
valve lifts. Hydraulic control of the SRFF may be designed to achieve a low lift and a
high lift of the engine valve or may be designed such that a low lift is zero lift, or
results in valve deactivation. An alternative hydraulic lift assembly can include
hydraulically controlled switchable hydraulic lifter valves that provide two levels of
engine valve lift through a push rod, as is known by those skilled in the art.
[0003] . Traditionally, such variations in engine valve lift have been achieved
by using a cylinder head that has a complex system of fluid supply passages that
enable pressurized fluid to communicate with the hydraulic lift assemblies, which are
supported in the cylinder head. Cylinder heads with such an integrated hydraulic
system are necessarily specific to each engine family and entail numerous production
steps such as casting, boring, and finishing the network of channels provided in the
cylinder head.
[0004] U.S. Patent Number 6,584,951 issued July 1, 2003 to Patel, et. al and
commonly assigned to General Motors Corporation, discloses an engine assembly that
requires a separate individual hydraulic circuit module for each engine cylinder which
achieves selective deactivation of each cylinder in accordance with the hydraulic
controls provided within the cylinder module associated with the cylinder. The
cylinder modules of the '951 patent utilize a solenoid valve to selectively block oil

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flow from a flow channel to an exit port of the module and thereby build oil pressure
in the flow channel and in lifter openings of each collapsible hydraulic lifter valve
associated with each cylinder. The oil pressure actuates the collapsible lifters to
enable cylinder deactivation. The solenoid valve can also be controlled to permit the
flow, thus causing the hydraulic lift assembly to cause reciprocal lifting and lowering
(i.e., opening and closing) of the engine valve (i.e., actuating the cylinder). Thus,
each solenoid valve acts as a two-way on/off valve.
SUMMARY OF THE INVENTION
[0005] It is desirable to reduce hydraulic control system complexity and allow
packaging flexibility while providing dual valve lift and/or engine valve deactivation
capability for a specific engine. An apparatus is provided which functions as a single
hydraulic circuit module that permits valve lift control of multiple engine valves in
response to hydraulic controls within the hydraulic circuit module. The single
hydraulic circuit module may be applied to an overhead cam-type engine or a
pushrod-type valve gear train. The single hydraulic circuit module controls valve lift
of multiple cylinders, and preferably of multiple sets of cylinders, thereby reducing
the number of components required to enable variable valve lift and minimizing
packaging concerns in comparison with systems requiring a separate hydraulic circuit
module and/or separate hydraulic circuit integrated within the cylinder head for each
individual cylinder.
[0006] Specifically, the single hydraulic circuit module is for an engine
assembly having a cylinder head that at least partially forms a plurality of cylinders
and supports at least one hydraulic lift assembly for each of the cylinders. The
cylinder head is in fluid communication with a hydraulic fluid supply such as the
supply gallery of an engine block attached below the cylinder head. The single
hydraulic circuit module includes a solenoid valve and a housing that supports the
solenoid valve. The housing at least partially forms a fluid supply passage and a
control passage. The solenoid valve is positioned between the passages and is
controllable to vary the volume (and therefore the pressure) of fluid flow from the
fluid supply passage to the control passage. The housing is configured for attachment
to the cylinder head so that the fluid supply passage is in fluid communication with
the fluid supply gallery and the control passage is in fluid communication with

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hydraulic lift assemblies for a first set of the cylinders. Control of the solenoid valve
thereby allows the hydraulic lift assemblies for the first set of cylinders to be
controlled to a low lift or a high lift position, corresponding with the volume of fluid
flow permitted by the solenoid valve. The low lift position may be a zero-lift position
resulting in cylinder deactivation.
[0007] Preferably, the apparatus includes a second solenoid valve supported
by the housing, in which case the housing at least partially forms a second control
passage and the second solenoid valve is positioned between a supply passage and the
second control passage. The second solenoid valve is controllable to vary fluid flow
and pressure from the fluid supply passage to the second control passage. The second
control passage is in fluid communication with hydraulic lift assemblies of the second
set of cylinders when the housing is attached to the cylinder head. Thus, different sets
of cylinders may be controlled to achieve variable lifts independently from one
another. The ability to control different sets of engine valves independently solves
issues caused by engine timing. The engine valves are timed such that the various
cylinders are at different points in the combustion cycle. It is not advantageous to
switch from a higher valve lift to a lower valve lift, or from a lower valve lift to a
higher valve lift, during certain points of the combustion cycle. For instance, the
switch may more highly stress the engine valve train components or cause
unacceptable audible noise during some points of the cycle. The single hydraulic
circuit module can control engine valve lift through hydraulic control of sets of
hydraulic lift assemblies at different sets of the cylinders independently of one
another, thus allowing the switch in valve lift to be accomplished at an optimal point
in the combustion cycle for each cylinder set.
[0008] In one aspect of the invention, the housing of the single hydraulic
circuit module forms separate chambers each configured to receive one of the
solenoid valves. The supply passage and the control passages may each include a
channel formed on an outer surface of the housing and an aperture extending through
the channel that is in fluid communication with a fluid supply (in the case of the
supply passage) and the chamber (in the case of each respective control passage).
[0009] Various features may be provided within the apparatus including a
filter positioned in the supply passage upstream of the solenoid valve to filter debris
that may otherwise affect valve performance. Additionally, a gasket may be provided

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that circumscribes the fluid supply channel and the control passage(s) for sealing the
apparatus when it is attached to the cylinder head. Furthermore, a weep channel may
be formed on the surface of the housing to circumscribe the fluid supply passage and
the control passage(s). The weep channel is circumscribed by the gasket. Thus, any
tluid seeping out of the fluid communication between the module and the cylinder
head will be collected in the weep channel. Preferably, a drain passage is provided in
the cylinder head opposite the weep channel to allow drain back to the fluid supply.
[0010] The single hydraulic circuit module can provide hydraulic control for
dual valve lift of intake valves and/or exhaust valves associated with the respective
cylinders. Separate feed passages are provided in the cylinder head that are in fluid
communication with the first and second control passages when the module is
attached to the cylinder head. The first feed passage provides control fluid to
hydraulic lift assemblies at the first set of cylinders and the second feed passage
provides control fluid to hydraulic lift assemblies at the second set of cylinders. The
first and second sets of cylinders may be associated with a single overhead camshaft.
For instance, the first set and the second set may all be intake valves operatively
connected with an intake camshaft or may all be exhaust valves operatively connected
with an exhaust camshaft. Alternatively, the first and second sets of cylinders may be
associated with two overhead camshafts, such as an intake camshaft and an exhaust
camshaft. In this instance, the single hydraulic circuit module may control hydraulic
lift at intake and exhaust valves of the first set of cylinders, or at intake and exhaust
valves at the second set of cylinders.
[0011] Flexible packaging is possible due to the minimal packaging space
required by a single hydraulic circuit module. For instance, the single hydraulic
circuit module may be attached to the cylinder head between adjacent ones of the
cylinders, such as between adjacent spark plug towers and the intake and exhaust
camshafts. For other engine families, the module may be mounted on the rear of the
cylinder head, i.e., on the rear side thereof.
[0012] The above features and advantages and other features and advantages
of the present invention are readily apparent from the following detailed description
of the best modes for carrying out the invention when taken in connection with the
accompanying drawings.

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BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIGURE 1 is a schematic perspective illustration of a portion of an
engine assembly having a first embodiment of a single hydraulic circuit module
attached at an outer surface of the cylinder head;
[0014] FIGURE! 2 is a schematic perspective illustration of the single
hydraulic circuit module of Figure 1;
[0015] FIGURE 3 is a schematic side illustration of a hydraulic lift assembly
having a hydraulic lash adjuster and an engine valve and hydraulically controllable by
the single hydraulic circuit module of either Figures 1 or 4;
[0016] FIGURE 4 is a schematic perspective illustration of a second
embodiment of a single hydraulic circuit module for controlling lift of an engine valve
such as that of Figure 3;
[0017] FIGURE 5 is a schematic illustration in elevational view of the single
hydraulic circuit module of Figure 4; and
[0018] FIGURE 6 is a schematic perspective illustration of a portion of an
engine assembly having the single hydraulic circuit module of Figures 4 and 5 (shown
partially in phantom and in cross-section at the arrows shown in Figure 4) attached at
a side surface of a cylinder head.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Referring to Figure 1, a single hydraulic circuit module 10 is attached
to a cylinder head 12 of a cylinder head assembly 14 which represents a portion of
an engine assembly 16. The single hydraulic circuit module 10 is attached with
three bolts 18 received through three respective fastener openings 20 (two shown in
Figure 2) and through corresponding mating engine openings 22 to secure the
module 10 to an outer surface 23 of the cylinder head 12.
[0020J The engine assembly 16 is an overhead cam-type with a separate inlet
camshaft and exhaust camshaft (not shown in Figure 1 but inlet camshaft shown in
Figure 3) for lifting and lowering of inlet valves and exhaust valves, respectively.
The inlet camshaft rotates about inlet camshaft axis 24 and the exhaust camshaft
rotates about exhaust camshaft axis 26. The single hydraulic circuit module 10 is

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configured to control inlet valves at multiple cylinders. As will be explained herein,
module 10 controls a first set of inlet valves separately from a second set of inlet
valves. Although in the embodiment shown, the module 10 controls inlet valves, it
may alternatively control exhaust valves by providing a cylinder head with fastener
openings 20 and mating engine openings 22 repositioned so that the module 10 is
rotated 180 degrees with respect to its position in Figure 1 and can operatively
connect to exhaust valves aligned with the exhaust camshaft axis 26.
[0021] Referring to Figure 3, control of an engine valve to provide dual lift
will be briefly described. Figure 3 illustrates a hydraulic lift assembly 30, also
referred to as an SRFF assembly supported by the cylinder head 12. The SRFF
assembly 30 is pivotally mounted on a hydraulic lash adjuster 32, and contacts the
valve stem 34 of an engine inlet valve 36 that selectively opens and closes an inlet
passage 38 to a cylinder 40 partially formed by the cylinder head 12. The engine
inlet valve 36 is selectively lifted and lowered in response to rotation of an inlet
camshaft 42 on which multiple cam lobes are mounted. The inlet camshaft 42
rotates about inlet camshaft axis 24.
[0022] The SRFF assembly 30 includes an inner rocker arm 44 which
rotatably supports a roller element 46. The inner rocker arm 44 is positioned
between outer rocker arms 48, one of which is visible. The other outer rocker arm
48 is positioned on the opposite side of the inner rocker arm 44 and is configured
exactly like the rocker arm 48 visible in Figure 3. A first low lift cam lobe 50
rotates with the camshaft 42 and is in operative contact with the roller element 46
mounted on the inner rocker arm 44. The inner rocker arm 44 is in contact with the
valve stem 34. The inner and outer rocker arms 44, 48 are both pivotable about an
axis through pivot point 53. The arms 44, 48 may selectively be pivotable relative
to one another or connected together for common pivoting about pivot point 53.
High lift is provided by selectively pinning the inner arm 44 and the outer arm 48
together for common pivoting about pivot point 53. When the inner rocker arm 44
pivots freely with respect to the outer rocker arm 48, action of the high lift cam lobe
52 on the outer rocker arm 48 does not affect lift of the engine inlet valve 36.
Instead, the high lift cam lobe 52 simply causes the outer rocker arm 48 to move

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relative to the inner rocker arm 44 about the pivot point 53 in "lost motion" without
any impact on the lift event of the engine inlet valve 36. Rather, lift of the engine
inlet valve 36 is affected only by action of the low lift cam lobe 50 on the roller
element 46 as transferred to the engine inlet valve 36 via the inner rocker arm 44,
which contacts the valve stem 34.
[0023] When high valve lift is desired, the outer rocker arm 48 may be
connected for common pivoting with the inner rocker arm 44. When this occurs,
the effect of the high lift cam lobe 52 on the outer rocker arm 48 is transferred to
the inner rocker arm 44 and to the engine inlet valve 36. Switching between the low
lift and high lift event is affected by controlling the hydraulic pressure fed through
the hydraulic lash adjuster 32. The hydraulic lash adjuster 32 is in fluid
communication with a pin 54 transversely mounted with respect to the arms 44 and
46 at an axis through pivot point 53. During a low lift event, a relatively low
pressure of hydraulic fluid is fed through feed passage 60 to a chamber 62 formed
within the hydraulic lash adjuster 32. The feed passage 60 is formed or machined
within cylinder head 12. The chamber 62 is in fluid communication with a channel
64 which acts upon an inner transverse surface of the pin 54. The relatively low
pressure is insufficient to actuate the pin 54 outward to be received within a pin bore
56 formed in the outer rocker arm 48. When high valve lift is desired, an electronic
control unit (not shown) controls the single hydraulic circuit module 10 of Figure 1
and 2 to increase hydraulic fluid pressure provided in feed passage 60 thereby
increasing pressure on the pin 54 sufficiently to actuate it outward to lock the inner
rocker arm 44 to the outer rocker arm 48. A hydraulic lift assembly such as
assembly 30 is discussed in further detail in United States Patent Number
6,769,387, issued August 3, 2004 to Hayman et al., commonly assigned to General
Motors Corporation, which is hereby incorporated by reference in its entirety.
[0024] Operation of the single hydraulic circuit module 10 to vary the
hydraulic fluid pressure within the feed passage 60 is described below. It should be
noted, that the lift control provided by the control module 10 as described with
respect to the engine inlet valve 36 may also be applied to an exhaust valve such as
the exhaust valve 66 shown in Figure 3. It should also be appreciated that the

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second embodiment of a single hydraulic circuit module shown and described with
respect to Figures 4 through 6 herein also operates to control fluid pressure in a
similar feed passage in fluid communication with engine valves as described with
respect to the SRFF assembly 30, hydraulic lash adjuster 32 and engine inlet valve
36 of Figure 3. Although a SRFF assembly 30 having inner and outer rocker arms
44, 48 selectively connectable for common pivoting is described in Figure 3, other
types of hydraulic lift assemblies which are hydraulically controlled to allow
variable valve lift may also be employed within the scope of the invention. For
instance, the single hydraulic circuit module described herein may also be utilized
with respect to a push rod-type engine in which a pin within a hydraulic lash
adjuster is selectively engaged to control valve lift. The dual valve lift, i.e., the
low lift and the high lift events, may be such that the low lift event is zero lift,
resulting in cylinder deactivation. For instance, a controllable hydraulic lash
adjuster to provide cylinder deactivation is described with respect to a push rod-type
engine in U.S. Patent Number 6,584,951, issued July 1, 2003 to Patel et. al and
commonly assigned to General Motors Corporation, which is hereby incorporated
by reference in its entirety.
[0025] Referring now to Figure 2, the single hydraulic circuit module 10
will be described in greater detail. Module 10 includes a housing 68 which is
preferably cast and includes a plurality of fluid passages described herein. The fluid
passages are formed or machined in the housing 68. The housing 68 supports a first
solenoid valve 70 as well as a second solenoid valve 72. The housing 68 is formed
with a first chamber 74 in which a valve body 76 of the first solenoid valve 70 is
selectively translatable in response to hydraulic fluid pressure within the chamber
74. The housing 68 also forms a second chamber 78 which houses a second valve
body 80 of the second solenoid valve 72. The second valve body 80 is translatable
in response to hydraulic fluid pressure within the chamber 78.
[0026] The housing 68 is formed with flanges 82, two of which are visible in
Figure 2 and all three of which are visible in Figure 1. The two flanges 82 visible
in Figure 2 are formed with the fastener openings 20 that, when aligned with mating
engine openings 22, will allow the single hydraulic circuit module 10 to be attached

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to the cylinder head 12. Two of the flanges 82 visible in Figure 2 also partially
house a first control passage 84 and a second control passage 86. When the module
10 is attached to the cylinder head 12, the first control passage 84 aligns with a first
feed passage 60A formed in the cylinder head 12. The first feed passage 60A
allows hydraulic fluid at a controlled pressure to be supplied to a first set of engine
valves, as will be described herein. The second control passage 86 is in fluid
communication with a second feed passage 60B also formed in the cylinder head 12
which is in fluid communication with the second set of engine valves as will be
described herein. An additional flange 82 (which does not house a fastener opening
20), is also formed on the housing 68 and partially houses a supply passage 92
which, when the module 10 is attached to the cylinder head 12, aligns with a fluid
supply passage 94 formed in the cylinder head 12 which, in turn, is in fluid
communication with a fluid supply gallery 96 formed in the engine, and shown in
phantom in Figure 2. Those skilled in the art will readily understand the fluid
supply gallery 96 formed in the engine to be a portion of the cast engine to which
hydraulic fluid flows. Fluid may be supplied to the fluid supply passage 92 from
the supply passage 94 and gallery 96 via a pump (not shown). A filter 93 is
schematically shown positioned in the supply passage 92 to filter debris that might
otherwise be carried from the supply gallery 96 downstream to the chambers 74 and
78.
[0027] The fluid supply passage 92 has a worm-like configuration that is in
fluid communication with a portion of the first chamber 74 beneath the valve body
76. The first control passage 84 is also formed within the housing 68 and includes a
transverse portion positioned opposite the first and second solenoid valves 70, 72
with respect to the supply passage 92 and the second control passage 86. The
transverse portion of the first control passage 84 is positioned to be in fluid
communication with the chamber 74 opposite the supply passage 92. The valve
body 76 is sized to selectively partially interfere with the first control passage 84.
Specifically, when fluid is supplied through the supply passage 92 at a first,
relatively low pressure, the valve body 76 is pushed upward to only partially
obscure an opening 100 of the first control passage 84 at the chamber 74. Thus,

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fluid is able to flow to the first control passage 84 at a first flow volume. The fluid
then flows to the first feed passage 60A in the cylinder head 12 to be directed to a
first set of hydraulic lift assemblies as will be described below.
[0028] The supply passage 92 includes an intermediate portion 102 formed
between the first chamber 74 and the second chamber 78 and in fluid
communication therewith. Thus, fluid in the supply passage 92 is supplied to the
second chamber 78 via the first chamber 74 and the intermediate portion of the
supply passage 102. The fluid that collects in the second chamber 78 is of sufficient
pressure to lift the second valve body 80 such that it only partially interferes with an
opening 104 of second control passage at the chamber 78. Thus, a first fluid flow is
provided through the second control passage 86 to the second feed passage 60B of
the cylinder head 12 to be directed to a second set of hydraulic lift assemblies as
will be described below.
[0029] The solenoids 70, 72 are preferably electronically controlled by an
electronic control unit (not shown) to translate the valve bodies 76, 80 within the
respective chambers 74, 78.
[0030] First supply passage opening 106, second supply passage opening 108
and opening 115 of first control passage 84 are plugged after the supply passages
92, 102 are drilled in the module 10. Exhaust passages (not shown) are also
provided in fluid communication with each of the chambers 74, 78 to drain excess
fluid back to the engine fluid supply.
[0031] When the solenoid valves 70, 72 are controlled to position the valve
bodies 76, 80 such that the control passages 84, 86 are accessible to provide a first
amount of fluid flow, the first and second sets of hydraulic lift assemblies
respectively controlled via passages 84 and 86 and feed passages 60A and 60B lift
engine valves a first predetermined amount, that is a relatively low lift level. When
a higher level of valve lift is desired, the first and second solenoid valves 70, 72 are
controlled by the electronic control unit (not shown) to lift respective valve bodies
76, 80 to allow unobstructed flow through the openings 100, 104 of the respective
control passages 84, 86. Thus, fluid is provided at a second, higher pressure level
through the first and second control passages 84, 86 and respective feed channels

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60A, 60B to the first and second sets of hydraulic lift assemblies to cause a second,
higher predetermined amount of engine valve lift.
[0032] Referring again to Figure 1, the single hydraulic circuit module 10 is
attached between spark plug towers 110 of adjacent engine cylinders. Specifically,
the cylinder head 12 partially forms six separate cylinders 112A, 112B, 112C,
112D, 112E and 112F, which may be referred to as the first through sixth cylinders,
or cylinders 1-6 respectively. The single hydraulic circuit module 10 is positioned
between the spark plug towers 110 of the third and fourth cylinders, 112C and
112D. When the intake and exhaust camshafts are installed to rotate about the axes
24 and 26, respectively, the module 10 is positioned below the camshafts.
Electrical connector portions of the solenoid valves 70, 72 are positioned near the
upper ends of the valves 70, 72 to be easily accessible for connection to a wiring
harness and/or electronic control unit. When the module 10 is attached to the
cylinder head 12, the supply passage 92 is aligned with a fluid supply gallery
positioned therebelow, as shown by gallery 96 in Figure 2. The first control
passage 84 aligns with the first feed passage 60A. The first feed passage 60A is in
fluid communication with a hydraulic lash adjuster identical to hydraulic lash
adjuster 32 of Figure 3 at each of the first, second and third cylinders, 112A, 112B
and 112(1 Similarly, the second control passage 86 is aligned with a second feed
passage 60B which is placed in fluid communication with hydraulic lash adjusters
such as those described with respect to Figure 3 for cylinders 4, 5 and 6 (112D,
112E and 112F), with the second feed passage 60B being operatively connected with
respect to the hydraulic lash adjuster similar to the operative connection of hydraulic
lash adjuster 32 with feed passage 60A as shown in Figure 3.
[0033] Thus, the single hydraulic circuit module 10 allows lift control of
multiple engine valves. In fact two sets of multiple engine valves are controlled by
module 10, the first set being engine valves located at cylinders 1 through 3 (112A,
112B and 112C), and the second set being engine valves located at cylinders 4
through 6 (112D, 112E and 112F). By removing the supply passage 92 and control
passages 84 and 86 from the cylinder head 12 and instead packaging them in control
module 10, control of multiple valves is afforded while reducing the complexity of

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the cylinder head 12. Additionally, the module 10 may be preassembled and tested
prior to attachment to the cylinder head.
[0034] Referring to Figure 4, a second embodiment of a single hydraulic
circuit module 210 will now be described. The module 210 includes a housing 268
which supports first and second solenoid valves 270, 272, respectively. As shown
in Figure 5, the solenoid valves 270, 272 are supported on first and second flanges
271, 273 of housing 268, which secure the valves 270, 272 via valve bolts 275.
The housing 268 also forms first and second chambers 274, 278 respectively. The
first chamber 274 houses the first solenoid valve body 276 which is visible in Figure
6. The second chamber 278 houses the second solenoid valve body 280, also visible
in Figure 6. Referring again to Figure 5, the housing 268 has bolt openings 220
which allow the housing 268 to be connected to a cylinder head 212 as illustrated in
Figure 6 via bolts 218. When assembled, electrical connector portions 277, 279 of
the respective solenoid valves 270, 272 are accessible above the housing 268.
[0035] Referring now to Figure 4, the housing 268 is preferably a cast
member that forms a supply passage 292. Supply passage 292 includes a fluid
supply channel 225 as well as a first supply aperture 227 and a second supply
aperture 229. The supply apertures 227 and 229 extend through the housing 268.
Referring to Figure 6, which shows the housing 268 taken in partial cross-sectional
view at the arrows shown in Figure 4, when the supply module 210 is mounted to
the cylinder head 212, the fluid supply passage 292 is in fluid communication with a
supply channel 294 in the cylinder head 212 that communicates with a fluid supply
gallery 296 in the engine block (not shown) to which the cylinder head 212 is
designed to be attached to form a completed engine assembly 216. Thus, fluid is
provided through the fluid supply channel 294 to the fluid supply passage 292 and
through the respective fluid supply apertures 227 and 229 to the solenoid valve
bodies 276 and 280.
[0036] Referring again to Figure 4, the housing 268 also forms a first
control passage 284 that includes a first control channel 285 as well as a first control
aperture 287. The first control aperture 287 extends through the housing 268 and is
in fluid communication with the first chamber 274.

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[0037] The housing 268 also is formed with a second control passage 286
which includes a second control channel 288 as well as a second control aperture
289. The second control aperture 289 extends through the housing 268 in fluid
communication with the second control chamber 278 (shown in Figure 5).
[0038] Referring to Figure 6, the first control passage 284 is in fluid
communication with the first valve body 276 through the first control aperture 287,
and with the first intake valve feed passage 260A formed in the cylinder head 212,
which is aligned with the first control passage 284 when the housing 268 is bolted to
the cylinder head 212. The first control passage 284 also aligns with a first exhaust
valve feed passage 260B provided in the cylinder head 212. The second control
passage 286 is in fluid communication with the second valve body 280 through the
second control aperture 289 and is in fluid communication with the second intake
valve feed passage 261A and a second exhaust valve feed passage 261B, both of
which are provided in the cylinder head 212.
[0039] The cylinder assembly 214 is an overhead cam-type with an intake
camshaft (not shown) that rotates about an intake camshaft axis 224 and an exhaust
camshaft that rotates about an exhaust camshaft axis 226. The cylinder head 212
partially forms four cylinders indicated schematically by upper ends thereof. The
cylinders include a first cylinder 212A, a second cylinder 212B, a third cylinder
212C and a fourth cylinder 212D. The first intake feed passage 260A routes
through the cylinder head 212 to the vicinity of the first and second cylinders 212A,
212B to provide hydraulic fluid to hydraulic lift assemblies located adjacent
cylinders to cause lift of engine inlet valves as described with respect to the valve
train, including hydraulic lash adjuster 32, SRFF assembly 30 and engine inlet valve
36, of Figure 3.
[0040] The second intake valve feed passage 261A is routed through the
cylinder head 212 to allow fluid communication with hydraulic lift assemblies
positioned to cause lift of engine inlet valves for cylinders 3 and 4, 212C and 212D,
respectively.
[0041] Similarly, the first exhaust feed passage 260B routes through the
cylinder head 212 to provide hydraulic fluid pressure to hydraulic lift assemblies

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positioned to cause lift of engine exhaust valves located at cylinders 1 and 2, 212A,
212B, respectively. The second exhaust feed passage 261B routes through the
cylinder head 212 to allow fluid communication with hydraulic lift assemblies
positioned to cause lift of engine exhaust valves at cylinders 212C and 212D.
Cylinders 1 and 2 are a first set of cylinders having a first set of hydraulic lift
assemblies (either for engine intake valves or engine exhaust valves) associated
therewith. Cylinders 3 and 4 are a second set of cylinders having a second set of
hydraulic lifters valves (either for engine intake valves or engine exhaust valves)
operatively associated therewith and connected thereto.
As shown in Figure 6, the first and second solenoid valve bodies 276, 280
are positioned between the fluid supply passage 292 and the respective first and
second control passages 284, 286 to partially block fluid flow to the respective
chambers 274, 278 (shown in Figure 5), thus permitting only a first, relatively low
level of hydraulic fluid flow and associated pressure to the respective control
passages 284, 286. Accordingly, when controlled to be in such a position, the valve
bodies 276 and 280 allow only a first level of fluid flow to the respective hydraulic
lift assemblies of the first and second cylinders sets 212A - 212B, 212C - 212D,
respectively. However, an electronic control unit (not shown) controls the solenoid
valves 270, 272 to allow the valve bodies 276, 280 to translate within the chambers
274, 278 so that a greater level of fluid flow, and thus fluid pressure, is provided
from the supply passage 292 to the respective first and second control passages 284,
286. Those skilled in the art will readily understand the use of an electronic control
unit to shift the position of a solenoid valve body to change fluid flow permitted past
the valve body. It should be appreciated that the solenoid valves 270, 272 may be
controlled separately from one another to allow a low pressure or high pressure flow
situation independently of the other valve. Alternatively, the solenoid valves 270,
272 may be controlled to simultaneously switch from low flow to high flow, or vice
versa. Thus, by controlling the solenoid valves 270, 272 fluid flow and associated
pressure to the respective cylinder sets 212A-212B, 212C-212D is controlled to
allow a low lift or high lift of associated engine inlet valves or exhaust valves of

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each respective set. A single hydraulic circuit module 210 thus controls inlet and
exhaust valves on four cylinders.
[0042] The housing 268 is bolted to an outer surface 223 which in this case
is a side of the cylinder head 212. As used herein "side" means an outer surface of
the cylinder head 212 that is generally parallel with the cylinders 212A, 212D. The
side 223 in Figure 6 is positioned rearward when the engine assembly 216 is
packaged in a vehicle. When the housing 268 is connected to the cylinder head 212,
the electrical connected portions 277 and 279 of the respective solenoid valves 270,
272 are easily accessible for testing, repair, and connection to an electronic control
unit, as can be seen in Figure 6.
[0043] Referring again to Figure 4, other features of the single hydraulic
circuit module 212 will now be described. A filter 293 may be positioned in fluid
communication with the supply channel 294 to prevent debris from entering the
module 210. Housing 268 incorporates means for exhausting each of the solenoid
valves 270, 272. An exhaust passage 201 extends through the housing 268 in
communication with an upper region of the first chamber 274 shown in Figure 5.
Thus, fluid exhaust from the first solenoid valve 270 is provided through the exhaust
passage 201. As illustrated in Figure 6, the exhaust passage 201 is in fluid
communication with a drain passage 202 formed in the cylinder head 212 for
draining the first solenoid 270. Similarly, an exhaust passage 203 is formed in the
housing 268 (see Figure 4) and includes an aperture 205 extending through the
housing 268 to an upper region of the second chamber 278 of the second solenoid
valve 272. As illustrated in Figure 6, when the housing 268 is secured to the
cylinder head 212, the exhaust passage 203 is in fluid communication with a drain
passage 207 formed in the cylinder head 212 for draining the second solenoid valve
272. Drain passages 202 and 207 formed in the cylinder head 212 are routed to a
drain portion of an engine block when the cylinder 212 is connected to the engine
block.
[0044] Referring again to Figure 4, the housing 268 is formed with a weep
channel 209 which circumscribes and is shallower depth than the fluid supply
channel 225 and the first and second control passages 284 and 286. The weep

GP-307652
16
channel 209 collects any fluid that may seep between the housing 268 and the outer
surface 223 (see Figure 6) of the cylinder head 212. The collected fluid is directed
through a weep channel drain 211 to the inside of the cylinder head 212 for drainage
back to an engine block when the engine block is connected to the cylinder head
212.
[0045] A gasket 213 circumscribes the weep channel 211, the supply channel
225, the first and second control passage 284, 286 and the exhaust passages 201 and
203. The gasket 213 ensures an adequate seal between the module 210 and the
cylinder head 212.
[0046] While the best modes for carrying out the invention have been
described in detail, those familiar with the art to which this invention relates will
recognize various alternative designs and embodiments for practicing the invention
within the scope of the appended claims.

GP-307652
17
CLAIMS
1. An apparatus for an engine assembly having a cylinder head,
wherein the cylinder head at least partially forms a plurality of cylinders and supports
at least one hydraulic lift assembly for each of said cylinders and is in fluid
communication with a hydraulic fluid supply gallery, the apparatus comprising:
a solenoid valve;
a housing supporting said solenoid valve and at least partially forming
a fluid supply passage and a control passage, wherein said solenoid valve is
positioned between said passages and is controllable to vary fluid flow from said fluid
supply passage to said control passage; and
wherein said housing is configured for attachment to said cylinder head
such that said fluid supply passage is in fluid communication with said fluid supply
gallery and said control passage is in fluid communication with the hydraulic lift
assemblies for a first set of said cylinders.
2. The apparatus of claim 1, further comprising:
a filter positioned in said supply passage upstream of said at least one
solenoid valve.
3. The apparatus of claim 1, further comprising;
a gasket circumscribing said fluid supply channel and said control
passage for sealing said apparatus when said apparatus is attached to said cylinder
head.
4. The apparatus of claim 3, further comprising:
a weep channel formed on a surface of said housing and
circumscribing said fluid supply passage and said control passage and being
circumscribed by said gasket.

GP-307652
18
5. The apparatus of claim 1, wherein said housing forms a
chamber configured to receive said solenoid valve; and wherein said supply passage
and said control passage each include a channel formed on an outer surface of said
housing and an aperture extending through said channel in fluid communication with
said chamber.
6. The apparatus of claim 1, wherein said solenoid valve is a first
solenoid valve, said control passage is a first control passage, and further comprising:
a second solenoid valve; wherein said housing supports said second
solenoid valve and at least partially forms a second control passage; wherein said
second solenoid valve is positioned between said fluid supply passage and said second
control passage and is controllable to vary fluid flow from said fluid supply passage to
said second control passage; and
wherein said second control passage is in fluid communication with the
hydraulic lift assemblies for a second set of the cylinders when said housing is
attached to said cylinder head, said second set not including any cylinders in said first
set of cylinders.
7. An engine assembly comprising:
a cylinder head in fluid communication with a hydraulic fluid supply
and at least partially forming a plurality of cylinders;
first and second sets of hydraulic lift assemblies operatively connected
to first and second sets of said cylinders, respectively, and responsive to a variation in
hydraulic fluid flow to cause a variation in lift of first and second sets of engine
valves respectively operatively connected thereto;
wherein said cylinder head has a feed passage in fluid communication
with said first set of hydraulic lift assemblies; and
a single hydraulic circuit module connected to an outer surface of said
cylinder head and having:

GP-307652
19
a housing that at least partially forms a supply passage and a
control passage, wherein said supply passage is in fluid communication with said
fluid supply and said control passage is in fluid communication with said feed
passage; and
a solenoid valve supported by said housing and positioned
between said supply passage and said control passage and controllable to vary flow
from said fluid supply passage to said control passage;
said single hydraulic circuit module thereby permitting variable lift of
said engine valves operatively connected to said first set of hydraulic lift assemblies
in response to control of said solenoid valve.
8. The engine assembly of claim 7, further comprising:
a rotatable overhead camshaft operatively connected with said first set
of hydraulic lift assemblies to cause reciprocal lifting and lowering of said first set of
engine valves in response to rotation of said camshaft.
9. The internal combustion engine of claim 7, wherein said feed
passage is a first feed passage, said control passage is a first control passage and said
solenoid is a first solenoid; wherein said cylinder head has a second feed passage in
fluid communication with said second set of hydraulic lift assemblies; wherein said
housing at least partially forms a second control passage; and further comprising:
a second solenoid valve supported by said housing and positioned
between said supply passage and said second control passage and controllable to vary
fluid flow from said fluid supply passage to said second control passage;
said single hydraulic circuit module thereby permitting variable lift of
said second set of engine valves operatively connected to said second set of hydraulic
lift assemblies in response to control of said second solenoid valve and independently
of said first set of said engine valves operatively connected to said first set of
hydraulic lift assemblies.
10. The engine assembly of claim 9, further comprising:

GP-307652
20
a rotatable overhead camshaft operatively connected with at least one
of said first set and said second set of hydraulic lift assemblies to cause reciprocal
lifting and lowering of said respective one of said first and said second set of engine
valves in response to rotation of said camshaft.
11. The engine assembly of claim 10, wherein said rotatable
overhead camshaft is operatively connected with both said first set and said second set
of hydraulic lift assemblies to cause reciprocal lifting and lowering of both said first
and said second set of engine valves in response to rotation of said camshaft.
12. The engine assembly of claim 10, wherein said rotatable
overhead camshaft is a first overhead camshaft operatively connected with said first
set of hydraulic lift assemblies, and further comprising:
a second overhead camshaft operatively connected with said second set
of hydraulic lift assemblies, wherein said first set of engine valves are intake valves
and said second set of engine valves are exhaust valves.
13. The engine assembly of claim 7, wherein said single hydraulic
circuit module is attached to said cylinder head between adjacent ones of said
cylinders.
14. The engine assembly of claim 7, wherein said single hydraulic
circuit module is attached to said cylinder head on a side thereof.
15. A cylinder head assembly for an engine comprising:
a cylinder head in fluid communication with a fluid supply gallery and
at least partially forming a plurality of cylinders;
first and second sets of engine valves operatively connected to first and
second sets of said cylinders, respectively, and responsive to a variation in hydraulic

GP-307652
21
pressure within first and second sets of hydraulic lift assemblies to cause a variation in
engine valve lift;
a rotatable overhead camshaft operatively connected with at least one
of said first set and said second set of engine valves to cause reciprocal lifting and
lowering thereof in response to rotation of said camshaft;
wherein said cylinder head has a first feed passage in fluid
communication with said first set of hydraulic lift assemblies and a second feed
passage in fluid communication with said second set of hydraulic lift assemblies; and
a single hydraulic circuit module connected to an outer surface of said
cylinder head and having:
a housing that at least partially forms a supply passage, a first
control passage and a second control passage, wherein said supply passage is in fluid
communication with said fluid supply gallery, said first control passage is in fluid
communication with said first feed passage, and said second control passage is in
fluid communication with said second feed passage;
a first solenoid valve supported by said housing, positioned
between said supply passage and said first control passage and controllable to vary
fluid flow from said fluid supply passage to said first control passage; and
a second solenoid valve supported by said housing, positioned
between said supply passage and said second control passage and controllable to vary
fluid flow from said fluid supply passage to said second control passage;
said single hydraulic circuit module thereby permitting variable lift of
said first and second sets of engine valves in response to control of said first and
second solenoid valves, respectively.

A single hydraulic circuit module is provided for controlling valve lift
at multiple cylinders in an engine. The single module includes a housing that at least
partially forms a supply passage and a control passage. The supply passage is in fluid
communication with the fluid supply and the control passage is in fluid
communication with the feed passage. At least one solenoid valve is provided and
supported by the housing positioned between the supply passage and the control
passage. The solenoid valve is controllable to vary fluid flow from the supply
passage to the control passage to permit adjustment of hydraulic lift assemblies to
vary lift of engine valves in response to control of the solenoid valve.

Documents:

00083-kol-2008-abstract.pdf

00083-kol-2008-claims.pdf

00083-kol-2008-correspondence others.pdf

00083-kol-2008-description complete.pdf

00083-kol-2008-drawings.pdf

00083-kol-2008-form 1.pdf

00083-kol-2008-form 2.pdf

00083-kol-2008-form 3.pdf

00083-kol-2008-form 5.pdf

83-KOL-2008-(17-08-2012)-ABSTRACT.pdf

83-KOL-2008-(17-08-2012)-AMANDED CLAIMS.pdf

83-KOL-2008-(17-08-2012)-DESCRIPTION (COMPLETE).pdf

83-KOL-2008-(17-08-2012)-EXAMINATION REPORT REPLY RECEIVED.pdf

83-KOL-2008-(17-08-2012)-FORM-1.pdf

83-KOL-2008-(17-08-2012)-FORM-2.pdf

83-KOL-2008-(17-08-2012)-FORM-3.pdf

83-KOL-2008-(17-08-2012)-OTHERS.pdf

83-KOL-2008-(17-08-2012)-PA-CERTIFIED COPIES.pdf

83-KOL-2008-(17-08-2012)-PETITION UNDER RULE 137.pdf

83-KOL-2008-ASSIGNMENT.pdf

83-KOL-2008-CORRESPONDENCE OTHERS 1.1.pdf

83-KOL-2008-CORRESPONDENCE OTHERS 1.2.pdf

83-kol-2008-form 18.pdf

83-KOL-2008-OTHERS.pdf

83-KOL-2008-PRIORITY DOCUMENT.pdf

abstract-00083-kol-2008.jpg


Patent Number 256199
Indian Patent Application Number 83/KOL/2008
PG Journal Number 20/2013
Publication Date 17-May-2013
Grant Date 15-May-2013
Date of Filing 10-Jan-2008
Name of Patentee GM GLOBAL TECHNOLOGY OPERATIONS, INC.
Applicant Address 300 GM RENAISSANCE CENTER DETROIT, MICHIGAN
Inventors:
# Inventor's Name Inventor's Address
1 VIMESH M. PATEL 24129 ELIZABETH LANE NOVI, MICHIGAN 48374
2 TIMOTHY L. NEAL 589 LAURA LANE ORTONVILLE, MICHIGAN 48462
PCT International Classification Number F01B 29/00; F01B 31/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 11/669,619 2007-01-31 U.S.A.