(12) INTERNATIONALAPPLICATIONPUBLISHEDUNDER THE PATENT COOPERATIONTREATY (PCT)

Iâ€ž't.-,t...~B'....".' llIIlIIlllIlIlllIlIllIllIllIIlllIIlIllIllllllIlllIIIlllllIIlIIllllllIIllIlIlIIIIIIIIII(43) InternationalPublicationDate(10) InternationalPublicationNumber

30 October 2008 (30.10.2008)~P(51) International Patent Classification:
FOLL 9/02 (2006.01)(21) International Application Number:
PCT/US2007/021339(22) International Filing Date: 4 October 2007 (04.10.2007)(25) Filing Language:

English(26) Publication Language:

English(30) Priority Data:
11/787,295

16 April 2007 (16.04.2007)

US(71) Applicant (for all designated States except US): LGD
TECHNOLOGY, LLC [US/US]; 11200 Fellows Creek
Drive, Plymouth, MI 48170 (US).
(72) Inventor; and(75) Inventor/Applicant (for US only): LOU, Zheng [US/US];
11200 Fellows Creek Drive, Plymouth, MI 48170 (US).
(74) Common Representative: LOU, Zheng; 11200 Fellows
Creek Drive, Plymouth, MI 48170 (US).

Qoog/$30374(81) Designated States (unless otherwise indicated, for every
kind of national protection available): AE, AG, AL, AM,
AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY BZ, CA, CH,
CN, CO, CR, CU, CZ, DE, DK, DM, DO, DZ, EC, EE, EG,
ES, FI, GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL,
IN, IS, JP, KE, KG, KM, KN, KP, KR, KZ, LA, LC, LK,
LR, LS, LT, LU, LY, MA, MD, ME, MG, MK, MN, MW,
MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PG, PH, PL,
PT, RO, RS, RU, SC, SD, SE, SG, SK, SL, SM, SV, SY,
TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA,
ZM, ZW.
(84) Designated States (unless otherwise indicated, for every
kind of regional protection available): ARIPO (BW, GH,
GM, KE, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, ZM,
ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM),
European (AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI,
FR, GB, GR, HU, IE, IS, IT, LT, LU, LV, MC, MT, NL, PL,
PT, RO, SE, SI, SK, TR), OAPI (BF, B J, CF, CG, CI, CM,
GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG).
Published:without international search report and to be republishedupon receipt of that report(54) Title: VARIABLE VALVE ACTUATOR WITH A PNEUMATIC BOOSTER(57) Abstract:Actuators,andcorrespondingmethodsand

116
~i

30

90

L1
8

2
00

FIGURE1systems for controlling such actuators, provide independent
valve control with a large initial or opening force. In an exemplary embodiment, an actuator includes a driver further
including a housing defining a longitudinal axis and firstand second directions, an actuation mechanism capable ofgenerating actuation force at least in the first direction, anda rod with one end operably connected with at least one partof the actuation mechanism and with the other end available for an operable connection with a load such as an engine valve; at least one return spring operably connectedwith the rod through a spring retainer assembly and biasing
the rod in the second direction; and.a pneumatic booster
further including a pneumatic cylinder, a pneumatic piston operably connected with the rod through the spring retainer assembly and biasing the rod in the first direction, acharge mechanism providing a controlled fluid communication between the pneumatic cylinder and a high- pressure
gas source, and a bleed mechanism providing a controlled
fluid communication between the pneumatic cylinder to a
low-pressure gas sink.

WO 2008/130374

LOU-AH3

PC T/US2007/021339

005 2

VARIABLE VALVE ACTUATOR WITH A PNEUMATIC BOOSTER

REFERENCETO RELATEDAPPLICATIONThis application
claimspriority to U.S.PatentApplicationNo. 11/787,295,
flled on April 16, 2007,the entirecontentof which are incorporated
hereinbyreference.

FIELD

OF THEINVENTION

This inventionrelatesgenerallyto actuatorsand corresponding
methodsand

10

systemsfor controllingsuch actuators,and in particular,to actuatorsoffering
efficient, fast, flexible control with large openingforces.

BACKGROUND

OF THE INVENTION

A split four-strokecycle internal combustionengineis described.in U.S.
PatentNo. 6,543,225.It includesat leastonepowerpistonand a corresponding
Grst
15

or powercylinder,andat leastonecompression
pistonanda corresponding
secondorcompressioncylinder.The powerpistonreciprocatesthrougha powerstrokeand an
exhaust stroke of a four-stroke cycle, while the compression piston reciprocatesthrough an intake stroke and a compressionstroke. A pressurechamberor cross-over20

passageinterconnects
the compression
andpowercylinders,with an inlet checkvalve
providing substantiallyone-waygasflow f'romthe compression
cylinderto the crossover passage,and an outlet or cross-overvalve providinggasflow communication
betweenthe cross-overpassageandthe powercylinder.The enginefurther includes
an intake and an exhaustvalve on the compressionand power cylinders, respectively.

The split-cycle engine according to the referencedpatent and other related
developments
potentiallyoffersmany advantages
in fuel efficiency,especiallywhen
integrated with an additional air storage tank interconnected with the cross-overpassage,which makesit possibleto operatethe engineas an air hybrid engine.
Relative to an electrical hybrid engine, an air hybrid engine can potentially offer as.much, if not more, fuel economy benefits at much lower manufacturing and waste30

dispo'sal costs.

WO 2008/130374

PC T/US2007/021339

LOU-AH30052

To achievethe potentialbenefits,the air or air-fuel mixture in the cross-overpassagehas to be maintainedat a predeterminedfiring condition pressure,e.g.

approximately
270psi or 18.6bargage-pressure,for theentirefour strokecycle.The
pressuremay go muchhigherto achievebettercombustion
efficiency.Also, the5 opening windowof the cross-overvalvehasto be extremelynarrow,especiallyat
mediumandhighenginespeeds.
Thecross-overvalveopenswhenthepowerpistonisat or nearthe top deadcenter(TDC) andclosesshortly after that. Thetotal opening
windowin a split cycleenginemaybe as shortas oneto two milliseconds,comparedwith a minimumperiodof six to eightmillisecondsin a conventional
engine.To seal
10

againsta persistentlyhigh pressurein the cross-overpassage,a practicalcross-overvalve is most likely a poppetor disk valve with an outward (i.e. away from the powercylinder,insteadof into it) openingmotion.When closed,the valve disk or headispressuredagainstthe valve seatunderthe cross-overpassagepressure.To openthe
valve, an actuator has to provide an extremely large initial opening force to overcome

15

the pressureforce on the head as well as the inertia. The pressureforce drops
dramatically once the cross-over valve is open because of a substantial pressure-equalizationbetweenthe cross-overpassageand the power cylinder. Once the
combustion is. initiated, the valve should be closed as soon as desiredto prevent the
spread of the combustion into the cross-overpassage,which also entails, during a
20

certain period of combustion,a needto keep the valve seatedagainsta powercylinderpressurethat is potentially somewhathigher than the cross-overpassagepressure.In
addition, the cross-over valve needsto be d'eactivatedwhen the power stroke is not
active in certain phasesof the air hybrid operation. Like conventional engine valves,the seating velocity of the cross-overvalve has to be kept under a.certain limit toreducenoise and maintain adequatedurability.
In summary, a cross-over valve actuator has to offer a large initial opening
force, a substantial seating force, a reasonablylow seatingvelocity, a high actuation
speed,and timing flexibility while consumingminimum energy by itself. Most, if notall, conventions engine valve actuationsystemsare not able to meet thesedemands.

WO 2008/130374

LOU-AH300

PC T/US2007/021339

-3-

52

SUMMARY

OF THE 1NVENTION

Brieflystated,in oneaspectof theinvention,onepreferredembodimentof anactuatorincludesa driverfurtherincludinga housingdefininga longitudinalaxis andfirst and seconddirections, an actuation mechanismcapable of generatingactuation
5 force

at least in the first direction, and a rod with one end operably connectedwith atleastone part of the actuationmechanismand with the other end availablefor an

operableconnection
with a loadsuchasan enginevalve;at leastonereturnspring
operablyconnectedwith the rod througha springretainerassembly
andbiasingthe
rod in the second direction; and a pneumatic booster further including a pneumatic

10cylinder, a pneumaticpiston operablyconnectedwith the rod through the spring
retainerassemblyand biasing the rod in the first direction, a chargemechanism
providing a controlledfluid communicationbetween the pneumaticcylinderand ahigh-pressuregas source, and a bleed mechanismproviding a controlled fluid
communicationbetweenthe pneumaticcylinder to a low-pressuregassink.

In operation,the actuatorholds the load to a second-directionend position
with the force from the at-least-onereturn spring biasing in the seconddirection andovercomingthe sum of the rest of the forcesincluding those from the pneumatic
boosterand the load, without generatingthe actuationforce in the first direction fromthe actuation mechanism,and with the pneumatic booster being chargedthrough the20

charge mechanism to yield a substantial force in the first direction to oppose asubstantial load force in the second direction.

The actuator initiates the travel of the load in the first direction by generating
the actuation

force in the first

directionfrom the actuation

mechanism,

with

the

combination of the actuation force and the force from the pneumatic booster being
25

able to overcomethe sum of the rest of the forces including those from the at-leastone return spring and the load and accelerate the load in the first direction.

The actuator keeps the travel in the first direction with the actuation force inthe first direction until reaching the target stroke, and keeping the actuation force inthe first direction if the load needsto be held at the target stroke. The actuatorinitiates30

the return travel of the load in the seconddirection at least by turning off the actuation
force in the first direction

by the return spring.

so that the load is accelerated in the second direction at leastWO 2008/130374

PC T/US2007/021339

LOU-AH30052

The actuator bleeds off excess air in the booster cylinder through the bleed

mechanismduringat leastpart of the time perioddescribedin the aboveparagraphto
reducethe force from the pneumaticbooster,which is otherwisetoo excessively
resistant to the return travel of the load. It completes the return travel with a

5 decreasing forcefromthereturnspringandan increasing
forcefrom the pneumatic
booster, which help slow down the load
In another embodiment, the driver is a fluid driver; the actuation

10

mechanismcomprisinganactuationpiston,anactuationcylinder,first andsecond
fluid spacesin fluid communication
with first andsecondports,respectively;
andtherod beinga pistonrod operablyconnectedwith theactuationpistonandtheload.

In another embodiment, the driver is an electromagneticdriver; the actuation

mechanismcomprisingan armaturedisposedin an armaturechamber,and at leasta
first electromagnet
on the first directionsideof the armaturechamber,wherebybeing

15

ableto pull the armaturein thefirst directionwhenenergized;
andthe rod beingan
armaturerod operablyconnectedwith thearmatureandthe load.
In another embodiment, the charge mechanisin includes a charge orifice,wherebysubstantially.
restrictingthechargeflow rate.It mayalsoincludesa control
mechanismthat substantiallycloses off charge flow at least when the bleed
20

mechanismis actively bleeding off excessair.

The presentinventionprovidessignificantadvantages
over the prevailing
fluid actuators and their control, especially those neededfor the cross-over passage

engine valve that needsa largeinitial openingforce, a substantialseatingforce, a25

reasonably
low seatingvelocity,a highactuationspeed,andtimingflexibilitywhile
consuming
minimumenergyby itself. Thepneumatic
boosteris ableto providethat
largeinitial force,withoutaddingtoo muchconstruction
complexityor demanding
too muchenergyconsumption
or stretchingthe capacityandfunctionallimits ofthe fluid or electromagneticactuators,by tapping directly into the cross-overpassageor theair storagetank.With thechargemechanism,
theboostforcecanbe
30

directly adjusted to the varying operating pressurein the cross-over passage,

without sophisticatedactivecontrol.With the bleedmechanism,
the enginevalve

WO 2008/130374

LOU-AH3

PC T/US2007/021339

0052

returnforcecanbegreatlyreducedby makingtheboostforceto besubstantiallylower during the return stroke.

Withthepneumatic
booster,thedriver,beit a fluidor electromagnetic
one,
is able to concentrateon more or less conventionalvalve actuation,without the

5 design, functionandcostburdenassociatedwith the largeinitial openingforce,
whichconventionallyentailslargeflowrateandpackage
sizefor fluid driversand
high,if not impossible,
magnetic
forceandelectricalpowerfor electromagnetic
drivers.

Thepresent
invention,
together
withfurtherobjectsandadvantages,
will be10 best understoodby referenceto the following detaileddescriptiontaken in
conjunctionwith the accompanying
drawings.
BRIEF DESCRIPTION

OF THE DRAWINGSFIGURE 1 is a schematic illustration of one preferred embodiment of theengine valve actuator,which is at a closedstate;
FIGURE 2 is a schematicillustration of anotherpreferred embodiment,which

includesdesignvariationsin the fluid driver,the springretainerassembly,
andthepneumatic booster;

FIGURE 3 is a schematicillustration of anotherpreferred embodiment,which
includes a 3-way proportional valve and a chargevalve;
FIGURE 4 is a schematicillustration of anotherpreferred embodiment,which

includesa 4-way proportionalvalve, a fluid driver with a double-ended
piston rod,and a pneumaticboosterwithout a bleedmechanism;and
FIGURE 5 is a schematicillustration of anotherpreferred embodiment,which
includes an electromagnetic driver.

DETAILEDDESCRIPTION

OF THE INVENTION

Referringnow to Figure 1, a preferredembodimentof the inventionprovides
an actuatorincluding a fluid driver 30, an actuation3-wayvalve 90, an returnspring
72, anda pneumaticbooster85.The loador controltargetof the actuatoris an engine
valve

20.

WO 2008/130374

LOU-AH30052

PC T/US2007/021339-6-

Theactuation
3-wayvalve90 supplies
thefluid driver30througha second

port62ofthefluiddriver30.The3-way
valve90hastwoof itsthree
waysconnectedwitha low-pressure
P L fluid lineanda high-pressure
P H fluid line,andthethird
wayconnected
withthesecond
port62.A firstport60of thefluiddriver30is in fluid
5 communication directly with the low-pressure
P L fluid line.

Theactuation
3-wayvalve90is switchedeitherto a leftposition92or a rightposition
94.At theleftandrightpositions
92and94,thesecond
port62is in fluid
communication with the P H and P L lines, respectively.

10

The pressureP H can be eitherconstantor continuouslyvariable.Whenvariable,it is to accommodate
variabilityin systemfriction,enginevalveopening,airpressure,
theengine
valveseating
velocityrequirement,
etc.,and/orto saveoperatingenergywhenpossible.
Thepressure
P L canbesimplythefluid tankpressure,theatmospherepressure,or a fluidsystem
backuppressure.Thefluid system
backuppressurecanbesimplysupported
orcontrolled,forexample,
bya spring-loaded
check
15

valve, with or without an accumulator.The P L value is preferredto be as low as

possibleto increase
thesystem
efficiency,
andyethighenoughto helpprevent
fluid
cavitation.Whennecessary,The P L can be more tightly controlledas well. Whennecessary
and/orallowed,thetwo P L linesconnectedwith thetwo ports60 and62
maymaintaintwo pressure
values.Forexample,
thefirst port 60maybesimplyused20

to dump someleakageflow to the fluid tank (not shownin Figure 1). In this case,much of the first fluid spacemay be simply filled with air, insteadof the working
fluid (assumingthe working fluid is not air).

The enginevalve 20 includesan enginevalve head22 and an enginevalve
stem24. Theengine-valvehead22 includesa firstsurface28 anda secondsurface29,

25

whichin thecaseof a split-cycle
engine,areexposed
to a cross-overpassage
110andtheenginecylinder102,respectively.
Theenginevalve20 is operablyconnectedwiththe fluid driver 30 along a longitudinalaxis 116throughthe enginevalve stem24,
which is slideablydisposedin an enginevalve guide120.For easeof description,theassemblyandthe longitudinalaxis 116havefirst andseconddirections,whicharethe30

sameas the top and bottom directionsin Figure 1. The enginevalve guide 120 as
illustratedin Figure 1 does not look like a traditional enginevalve gqide, which
normallyis a sleevewith a muchlimited wall thickness.The guide120is designedto

WO 2008/130374

PC T/US2007/021339-7-

LOU-AH30052

besituatedin thecylinder
head82,overa valveassembly
opening
83,whichis large

enoughto slidethroughtheengine
valvehead
22during
assembly.
Thisisjustoneof
manypotential
assembly
options.
Thisdoesnotexclude
thepossibilityof addinga
traditional-looking
sleeveinsidetheguide120.Theguide120maycontainnecessary

5 engine coolant
andlubricant
passages(notshownin Figure1).
Whentheenginevalve20 is fully closed,the enginevalvehead22 is incontact
withanengine
valveseat26,sealing
off thefluidcommunication
betweenthecross-overpassage110 and the engine cylinder 102.

The fluid driver 30 comprisesan actuatorhousing70, an actuationpiston

10 40,andanactuation
cylinder50.Theactuation
piston40 is slideablydisposedintheactuation
cylinder50.Theactuation
piston40 is fixedonto a pistonrod46
betweena fasteningelement45 and a shoulder49. The actuationpiston 40
includesa first surface42 and a secondsurface44, and longitudinally dividesthe

actuationcylinder50intoa firstQuidspace
52(between
anactuation-cylinder
first
15

end 56 and an actuation-piston
first surface42) and a secondfluid space54(between
theactuation-piston
secondsurface44and.theactuation-cylinder
secondend58).Theradialclearances
aroundtheactuation
piston40andthepistonrod46
are substantiallytight, provide substantialfluid seal, and yet offer tolerable
resistance to relative20

motions.

The secondfluid space54 is in fluid communication
with the secondport

62througha second
flow passage
64'arounda neckfeature48 onthepistonrod.
The secondflow passage64 becomessubstantiallymore restrictivewhen theactuationpiston40 is closeto the actuation-cylinder
secondend58, with theshoulder49 longitudinallyapproachingand/or overlappingthe secondflow

25

passage
64.If a second
flow mechanism
is definedto includethe secondflow
passage
64,theneck48, andthe shoulder
49,thenthe secondflow mechanism
providessubstantiallyopenfluid communication
betweenthe secondfluid spaceandthe secondport.It providesa snubbing
functionwhenthe actuationpiston40
is close to the actuation-cylindersecondend 58. When desired,the second.Qow

30mechanism
may alsoincludea one-wayor checkvalve(not shownin Figure1),

WO 2008/130374

LOU-AH3

PC T/US2007/021339

005 2

providinga parallel,
substantially-open
fluidcommunication
fromthesecond
port
62 to the second Quid space54.

The first fluid space52 is in fluid communication
with thefirst port 60
withoutmuch flow restriction.

Thepistonrod46isoperablyconnected
withtheengine
valvestem24,andin this embodiment(as illustratedin. Figure 1) the rod 46 and stem 24 are
structurallythe samepart,which is not the only designoption.

A springretainer
assembly
74is designed'
to helpholdthereturnspring72
and transfer its force on to the engine valve stem 24. The return spring 72 as

10

illustratedin Figure1 is a singlemechanicalcompression
spring.This doesnot
excludeother designoptions,suchas a pair of compression
springsin parallel.
Thespring72 mayalsobein theform of theBellevilletypeor pneumatic
nature.
Thespringretainerassembly
74 includesa firstandsecondspringretainers
78 and 80 and a setof valve keepers76. The first springretainer78 also functions

15

or doublesasa pneumatic
piston,which is slideablydisposedinsidea pneumatic
cylinder 84, a cavity at the top of the enginevalve guide 120,to form thepneumaticbooster85.Theside,slidingwallsof thefirst springretainer78 andthe
pneumaticcylinder 84 maintainan air-tight seal and yet reasonablelevel of&iction with necessarylubricationand sealingmechanism(detailsnot in Figure 1).

20

The return spring 72 andthe pneumaticbooster85 apply forcesto the first retainer
78, and thus the engine valve stem 24, in the second and first directions,
respectively.The springretainerassembly74 is thus designedto sustainforcesin
both directions. The force &om the return spring 72 is applied to the first spring
retainer 78, and is transferred, through the valve keepers 76, to the engine valve25

stem24. The pneumaticforce &om the pneumaticcylinder 84 is primarily applied
to the first spring retainer 78, and is transferredto the valve stem 24 throughspring-retainerfasteningmeans81 (details of which are not illustrated in Figure1), the second spring retainer 80, and the valve keepers 76.

The pneumaticcylinder 84 is chargedor suppliedwith the pressurizedgas
30

or air &om the cross-overpassage110, a high-pressuregas source,through achargemechanismincluding a chargepassage112 and a chargeorifice 86. The

WO 2008/130374

I,OU-AH3

PC T/US2007/021339

005 2

chargeorifice86is designed
to bemorerestrictive
thanthecharge
passage
112
Thepassage
112andorifice86maybecombined
intoa single
restrictive
longorifice(notshownin Figure1).Thcseparate
construction
or existenceof thechargeorifice86mayeasethemanufacturing
process.
Thepneumatic
cylinder84
5 is alsointentionallydesigned
to haveanexpansion
118in its topportionsothata

substantially
air-tightsealbetween
thefirstretainer
78andthepneumatic
cylinder84 is keptonlywhentheenginevalve20 is seatedandwithina.predefined
distanceI.l of the enginevalvetravelin thefirst direction,beyondwhichthereis asubstantial
clearanceor bleedpassage
betweenthe pneumaticcylinder84 andthe
10 first retainer 78, and the pneumaticcylinder 84 is in substantialfluid
communication
with the atmosphereor a low-pressure
gas sink andyet is in a
restrictive fluid communication with the cross-over passage110.

Theactuationcylinder50offerssubstantial
roomlongitudinallysuchthatthe

actuation
piston40doesnottouchthefirstandsecond
ends56and58of thecylinder
1550whentheloador enginevalve20 is at its first-directionandsecond-direction
end

positions,
respectively;
Whentheengine
valve20is seatedor atits second-direction
cnd positionas shownin Figurc1, thereis still a distancebetweenthe actuationpistonsecondsurface44 and.the actuation-cylinder
secondend58 to accommodate
the enginevalvelashadjustment.
Whenthe enginevalve20 is fully openor at its
20

first-directionend position,thereis enoughforce Born the return spring72 and/or

enoughlongitudinalspacein thecylinder50to preventa.directcontactbetween
theactuation-piston
first surface42 andthe actuation-cylinder
first end56.
Alternatively,onemaydesignfor the enginevalve openingtravelto be limited

or definedby the physicalcontactbetween
the actuation-piston
first surface42 andthe actuation cylinder first end 56, or betweentheir equivalentsurfaces,withnecessary
snubbingor controlmeasures,
like thoseshownlaterin Figures2 and5.
The enginevalve head22 is generallyexposedto the pressureof the cross-overpassage
110onthefirst surface
28andthepressureof theenginecylinder102on
the second
30

surface

29.

The cross-section
areaof the first springretaineror the pneumaticpiston78 is

to be substantiallyequalto that of the engine-valve
headso that the pneumaticWO 2008/130374

LOU-AH30052

PC T/US2007/021339- 10-pressure
force
onthepneumatic
piston78substantiallycancels
thepressure
force
ontheengine-valve
6rstsurface
28whenthepressurein thepneumatic
cylinder84issubstantiallyequalto thatin thecross-overpassage,dueto fluidcommunication

throughthecharge
oriTice86.Alternatively,
thecross-section
area
ofthepneumatic
5 piston78istobeappreciably,
butnotnecessarily
substantially,
different
from,either
largeror smallerthan,thatof theengine
valvehead22.A larger
pneumatic
pistoncross-section
area,for example,offersanextraenginevalveopeningforcesothata
relativelymorecompactfluid driver30 is sufficient.

Thesystem
alsoexperiences
various&ictionforces,steady-state
flowforces,
10transientflow forces,andotherinertiaforces.Steady-state
Qowforcesarecausedbythehydrostaticpressure
redistributionduetofiow-induced
velocity
variation,
i.e.theBernoulli effect.Transientflow forcesare fluid inertial forces.Otherinertial forces
resultRomthe accelerationof objects,excludingQuidhere,with inertia,andtheyare

substantial
in an enginevalveassembly
becauseof the largemagnitudeof the15

acceleration or the fast timing.
POWER-OFFSTATE

At power-offstate,all fluid supplysources
P H andP L areat low or zero

gagepressure.
Thetotalfluidforceontheactuation
piston40is substantiallyequalto20

zero.Theenginevalvecanbe seatedor closedby the returnspring72 alone.The

seating
is evenmoresecure
if thepneumatic
piston78hasa smaller
diameterthantheenginevalvehead22,andthecross-overpassage
110is still suf6ciently
pressurized,
especiallyfor anair-hybridapplicationwith anair storagetank.

At the power-off,the defaultpositionof the actuation3-wayvalve90 ispreferably,
but not necessarily,
to bein its rightposition94 asshownin Figure1 sothat the secondQuid space54 is in fluid communicationwith the low pressureP L
fluid line andis surelyat a low or zerogagepressureif a secureenginevalve seating

is importantor critical.Immediately
afterengineoff, thehighpressure
P H fluid line
maybe still pressurized.
At the enginestart,the enginevalve20 canbe keptat the30

closedpositionwithout activelyswitchingthevalve90.
START-UP

WO 2008/130374

LOU-AH3

PC T/US2007/021339

-11-

005 2

To start-up
thesystem
fromthepower-offstate,all fluid supplysourcesarepressurized,
andtheactuation
3-wayvalve90is secured,eitherbydefault
or active
control,atitsrightposition
94asshownin.Figure1.Theengine
valve20is secured,atleastbythereturnspring72,attheclosed
orseated
positionasshown
in Figure1.
VALVE

OPENINGAND CLOSING

To opentheengine
valve20,theactuation
3-wayvalve90is switched
to itsleft position92.Thesecond
fluid space
54is opento thehigh.pressure
P H supply
throughthesecond
flow mechanism,
whilethe 6rst fluid space52 remains
to beexposedto thelowpressure
P L supply.Theresulting
differential
pressure
forceon10

the actuationpiston40 is in the 6rst direction(or upwardin Figure I) to overcome

primarilythespringforce,drivingopentheenginevalve20.At thesametime,thedownward differential air pressureforce on the enginevalve 20 is substantially15balancedby the upw'arddifferentialair pressure
forceon the pneumatic
piston78,
considering
thatthepneumatic
cylinder84 is underthe samepressure
asthe crossoverpassage
110.In a split-cycle
engine,thedominant
forceonanenginevalveis the
air pressureforce f'rom the cross-overpassage110. The incorporationof thepneumatic
piston78helpsbalance
outandcounter
thislargeforce,whichotherwise
demandsan extremelylarge and energy-intensiveactuator.

As soonasthe enginevalve 20 cracksopen,the enginecylinder 102is filled
20

rapidly,andits pressure
reaches
thecross-overpassagepressure
withina shortperiodof time, well beforetheenginevalve20 passesthe middlepoint of the openingstroke,
resulting in a rapid disappearanceof the differential pressureon the enginevalve
surfaces 28 and 29. During the same short period of time, the pressure in thepneumatic
cylinder84 andthedifferentialpressure
on thepneumatic
piston78 drop
rapidly as well becauseof its limited, predefinedinitial volume,its rapid volume
expansionassociatedwith the enginevalvemovement,a limitedamountof air inflow
throughthe chargeorifice 86, andthe bleedingoff of the air asthe pneumaticpiston
78 movesup a predefineddistanceLl, as shownin Figure 1, to the expandedtop
portion 118 of the pneumatic cylinder 84.
30

For the rest of the opening stroke or beyond the distanceLl, the airpressureforceson the pneumaticpiston 78 and the enginevalve 20 are minimum,

WO 2008/130374

LOU-AH30052

PC T/US2007/021339- 12-

andtheactuation
piston40 continues
to drivetheenginevalve20 in thefirst
direction(orupwardin Figure1)against
anincreasing
springforcefromthereturn

spring72untiltheengine
valvereaches
its full openposition,
whenthespringforceandthe fluid differentialforceacrossthe actuationpiston40 arebalanced,

5 which is expected
to bedynamic
withcertainovershootanddamped
oscillation,
considering
the spring-mass
natureof the construction.
Thereare however
measures,asshownin otherpreferred
embodiments(Figures2 and4), to havea
more definitive lift or full open position.

The enginevalve20 remainsopenas long asthe actuation3-wayvalve90
10 remainsat its left position92.Duringthis period,thepneumatic
cylinder84 keeps
receivinga smallstreamof air flow &omthechargeorifice86andkeeps'bleedingtheair out throughthe substantial
gapbetweenthe pneumaticpiston78 andits top,

expandedcylinderwall118.Thisenergy
losswill continue
untilthepneumatic
piston15

78is backatthelowerportionof thepneumatic
cylinder84.However,theenergyloss
is minimizedby therestrictivenatureof thechargeorifice86 andthelimitedengine
valveopeningperiodrelativeto theentirethermalcycle.

To startclosingtheenginevalve,theactuation3-wayvalve90is switchedto20

its right position 94, andthe secondfluid space54 is openbackto the low pressure
P L fluid. supply, resultingin a substantiallyzero pressuredifferential acrosstheactuationpiston 40. The return spring 72 is able to drive the enginevalve 20
downward.When the pneumaticpiston 78 passesthe expandedpart 118'of thepneumatic
cylinder84,a substantially
air-tightsealis establishedagainbetween
thepneumatic
piston18andthewallof thepneumatic
cylinder84,andthepressurein the25

pneumaticcylinder startsbuilding up primarily becauseof a shrinking cylinder
volumeasthe enginevalve20 andthusthepneumaticpiston18movedownward.The' pressurebuild-up is also assistedby the flow &om the chargeorifice 86. The
pneumatic cylinder 84 functions like a pneumatic spring, slowing down theadvancementof the enginevalve 20 and eventuallyhelping achievea soft-seatingwhen the engine valve 20 reachesthe engine-valveseat26.
Around the engine valve seatingor landing and shortly aAerthat, the pressurein the engine cylinder momentarily exceedsthe cross-overpassagepressurebecauseof the effect of the combustion,resulting in a transient differential pressureforce inWO 2008/130374

LOU-AH30052

PC T/US2007/021339-13-

thefirst directionor upward.Thepreload.
of thereturnspring72 shouldbedesigned
to beableto holdtheenginevalve20in seatedpositionagainstthistransient
upwarddifferentialforce on the enginevalve and also againstthe pressureforce from thepneumatic
cylinder84. Thepneumatic
cylinderpressure,at thismoment,is however

5 not equalto thefull cross-overpressure.
It is purposely
soby earlierbleeding
offthroughthe expanded
portion118of the pneumatic
cylinder84 andthe restrictive'
natureof the chargeorifice 86.
Thereafter, the engine cylinder pressuredrops below the cross-overpassage

10

pressureas the volumeexpandsfurther.Thepneumaticcylinderpressure
risesupfurtherthroughthe restrictedflow fromthe chargeorifice 86 duringthe restof theenginethermalcycle,whichis slowbut sureenoughto be readyfor thenextengine
valve opening event.

Figure2 depictsan alternativeembodimentof the inventionthatfeaturessome
variationsin the designof the fluid driver 30. The first Qow mechanism,which is15

the means of the fluid communication between the first port 60 and the first fluid

space52, includesa first undercut32 andat leastone first snubbinggroove33.
When the actuation-piston first surface 42 passes the first undercut 32
longitudinally in the first direction during an openingstroke,the working Quid issubstantiallytrappedin the first fluid space52, with only a limited outlet through20

the at-least-one first snubbing groove 33, resulting in a snubbing action to help

slow down the travel speedand reducepotential oscillation. When so desired,theactuation-cylinderGrst end can be longitudinally arrangedto provide a solid stop
. to the actuation-piston first surface 42, thus a well defined engine valve lift. If sodesired, a check valve (not shown in Figure 2) can be arranged to allow one-way
25

flow from the first port 60 into the end of the first fluid space 52 during thestarting phase of the engine valve closing stroke to avoid cavitation.
Similarly, the second flow mechanism, which is the means of fluid
communication between the second port 62 and the second fluid space 58,
includes a second undercut 34 and at least one second snubbing groove 35. When30

the actuation-piston second surface 44 passes the second undercut 34
longitudinally in the second direction during an closing stroke, the working fluid isWO 2008/130374

LOU-AH30052

PC T/US2007/021339- 14-

substantiallytrappedin the secondfluid space58, with only a limitedoutlet
throughtheat-least-one
secondsnubbing
groove35,resulting
in a snubbing
actionto helpslowdownthetravelspeedandachieve
soft-seating
for theenginevalve
20. It is desiredto leavea predefined
longitudinaldistancebetweenthe actuation-

5 cylinder second
endandtheactuation-piston
secondsurface44 to ensurea solid
contactandtight sealbetweenthe enginevalve head22 andthe valve seat26
whenthe enginevalve20 is seated,whichhasto be accommodated
at all engine
operating conditionsand throughoutthe engine's service life. When necessary,

additionalenginevalve lashadjustmentdevice(not shownin Figure2) is to be10

integrated in this and other embodiments.

The embodimentin Figure 2 further featuresvariationsin the designof thespringretainerassembly74. The secondspringretainer80, insteadof the firstspringretainer78,functionsor doublesasthepneumatic
piston80.It alsoincludes
two setsof valve keepers76b and 76c. This embodimentallows the enginevalve15

stem24 andthe pistonrod 46 to be physicallytwo separatepieces,unitedoperably
by the spring retainer assembly74 with necessaryfasteningmeans 106 or theequivalent.
This embodiment also shows variations in the charging and bleedingmechanisms for the pneumatic booster 85. It adopts at least one bleed hole 87 as20

the bleedpassage,insteadof an expandedwall 118 in Figure 1, for the pneumatic
cylinder 84 to dischargeits extra gaswhen the pneumaticpiston 80b travelsup apredefineddistance1.1 as shown in Figure 2. The bleed holes 87 may be fittedwith porous materials or filters (not shown) to reduce noise associatedthe bleeding
process. To save the effort and cost of drilling or casting the bleed holes 87, one

25

may also simply design the engine valve guide 120, and thus the pneumatic
cylinder 84, up to that height, causing the pneumatic piston 80b to be disengaged
Rom the pneumatic cylinder 84 once it travels up to that point, resulting in a wide
open bleeding process.

Onecan also use somepredefinedvariation (not shownin Figure 2) in the30

radial clearancebetweenthe pneumaticpiston 80b and the pneumaticcylinder 84.
Adopting an oppositeapproach,somediaphragm(not shownin Figure 2) may be

WO 2008/130374

LOU-AH30052

PC T/US2007/021339-15-

usedto completelysealoff leakagethroughthe radialclearance,
totallydependingon the at-least-onebleedhole 87 or its equivalentfor the control of the air or gas

massdischarge.Also, whendesired,onemay usea controlvalve(not shownin
Figure 2) to control its on/off state.

The chargeorifice 86b in Figure2 is regulatedby a controlmechanism
includingan orificegate89 anda stemundercut104,whicharenot opento eachotherwhenthe enginevalve20 travelsup a predefined
distanceL2 (as shownin
Figure2). Thedistance
L2 is preferablyto be equalor shorterthanthedistanceL1
so that the flow through the charge orifice 86b and thus the charging process are

10

substantiallyblockedwhen the dischargingprocess,throughthe bleedhole 87 orits equivalent,is active.This variationin the chargemechanism
will helpreduce
unnecessary,however small, energy loss.
Refer now to Figure 3, which is a drawing of yet another alternative
embodiment of the invention. In this fluid driver 30, a proportional or servo 3-way

15

valve 90c is used to control the fluid supply to the secondfiuid space54. The engine
valve or actuator position signal can be collected via a position sensor(not shown in
Figure 3). The feedback control will help achieve more precise control over theengine valve lift and seatingvelocity. The.proportional or servo valve 90c itself canbe actuateddirectly via various means(not shown in Figure 3), including solenoidsor

20

other electromagnetic means, electrohydraulic pilot valves, and piezoelectric
actuators.

This embodiment further features a charge valve 108, as a control mechanism,
along the charge passage 112 to help achieve better control over the charging process

for the pneumatic cylinder 84. The charge valve 108 has at least one of two major
functions: (1) to open the chargepassage112, allowing the pneumaticcylinder 84 tobe charged,before the enginevalve opening stroke, and close the charge,passage112
especially if the restrictive chargeorifice 86 is not used,eliminating or reducing leakflow when the pneumaticcylinder 84 is being bled; (2) to completely close off thechargepassage112 when the engine or that particular engine cylinder is power-off, as
30

in an air hybrid vehicle, minimizing leakageand preservingthe pressurizedair in the
cross-overpassageand/orthe air storagetank. For the first function, one chargevalve
108 is needed for each power cylinder of the split four-stroke cycle engine because

WO 2008/130374

LOU-AH30052

PC T/US2007/021339- 16-

eachpowercylinderhasitsuniquetiming.If onlythesecond
functionis needed,one
mayoptionallyuseonlyonecharge
valve108for anentireengine,
withthevalve108
controllinga commonchargepassage(not shownin Figure3) that eventuallybranchesinto tributarychargepassages(not shownin Figure3) for individualpower

5 cylinders (notshownin Figure3). Furtherfor thefirst function,thechargevalve108
may be optionallya proportionalvalve,insteadof an on/off valve.By beinga

proportional
valve,thecharge
valve108is ableto activelycontrol,for example,
theair pressurein thepneumatic
cylinder84 for variousfunctional,durabilityandNVH
needs.

10

At this andotherfigures,thechargepassage112is connectedto thecross-overpassage
110.Optionally,it canbeconriectedto theair storagetank(in thecaseof an
air hybrid vehicle) or a separatereservoir(not shownin the figures).The separate
reservoir may have its own pressure,which may be regulatedto help achieve
optimumchargingprocessfor theyneumaticcylinder84.
Refer now to Figure 4, which is a drawing of yet anotheralternative
embodimentof the invention. In this case,a proportional or servo 4-way valve 90d isused to control the fiuid supply both to the first and secondfluid spaces52 and 54.
This embodiment is able to provide actively-controlled actuation forces both in thefirst and second directions. Optionally, the piston rod 46 extends longitudinally20

through the Grst fluid space 52, becoming a double-ended piston rod. To have abiased or asymmetric differential fluid force, the two ends of the piston rod may
possesstwo different diameters,with the side with a smaller rod' diameterhaving alarger effective fluid pressuresurfacearea.
Still anothervariation or option is its lack of a bleedmechanism.The actuation
force in the second direction will easily help overcome the high air pressureforce&om the pneumaticbooster85 during the engine valve closing. The elimination of the
bleed mechanism will help simplify the construction of the pneumatic booster 85.
Without a bleed'mechanismor substantialleakage,the chargemechanism,including

the chargeorifice 86, is still neededto compensate
for potentialminor leakages,and30

adjust the pressureand air masslevel in the pneumaticbooster85 to accommodatethepressurelevel variation in the cross-overpassageor air storagetank. The actuatorneeds a lower boost force, for example, when the cross-over passagepressure isWO 2008/130374

LOU-AH30052

PC T/US2007/021339

â€” 17-lower.In this sense,the chargemechanismalsohasa balancefunction,which is eventruefor thepneumaticboosterswith a bleedmechanism.

Dependingontheapplication,
therestof theembodimentin Figure4 maystill
be integratedwith one of the bleedmechanisms
featuredin earlierembodiments
5 (illustrated in Figures1-3)if a lowerair pressure
forceis idealfor theenginevalve
seating process.

Refer now to Figure 5, which is a drawing of yet another alternative
embodiment of the invention. In this embodiment, an electromagnetic driver 130

replacesthefluid drivers30 in Figures1-4. Theelectromagnetic
driver130includes
10

a housing132,within which &om the top to thebottomarea first electromagnet
134,
an armature chamber 146, and a second electromagnet 136. The first and second

electromagnets
134and 136 further includetheir electricalwindingsand lamination
stacks,detailsof which arenot shownin Figure5. An armature138is disposedinside
the armature chamber 46 and between the first and second electromagnets 34 and 36

15

and is rigidly connectedto an armaturerod 140.The armaturerod 140 is slideably
disposedthroughthe secondelectromagnet
136andthe housing132,andis operablyconnected with the engine valve stem 24.

Whenpowered,the first and secondelectromagnets
134 and 136 atlxactthearmature 138 in the first (top) and second(bottom) directions, respectively.The first20

electromagnet134 is able to catchthe armature'138and keepthe enginevalve 20
openat the full lift. To crack openthe enginevalve 20 whenthe air pressureforceson the enginevalve 20 and the pneumaticpiston 80 are substantiallybalanced,thefirst electromagnet134 only needsto overcomethe preload from the return spring 72,

which is achievabledespitethe highly nonlinearnatureof the electromagnetic
force
because the overall lift for the cross-over engine valve and thus the air gap between

the armature 134 and the electromagnet134 are small. This can be further assisted,if

necessary,by designingthe pneumaticpiston 80 to be appreciablylargerthan theenginevalvehead22 andthus introducinga differentialair pressureforcein the first
direction.
30

To close the engine valve 20 &om the full open position, the firstelectromagnet
134 is de-energized,
and the enginevalve 20 is pusheddown by the
returningforceof the returnspring72, with the pulling assistance,
if necessary,&omWO 2008/130374

LOU-AH30052

PC T/US2007/021339- 18-

an energized
secondelectromagnet
136.Duringthelaterphaseof theclosing,thepneumatic
cylinder86is pressurized
by volumetriccontraction
andoptionalcharging
actionthroughthechargeorifice86b,andit helpsslowdowntheenginevalve20 toachievest-seating. A further retardingactioncan be achievedby re-energizingthe
5 first electromagnet
134in a controlledway, resultingin a desiredpulling force in thefirst directiondependingon theoperationalneedsor feedbacksignal.

Thepullingforcein the seconddirectionfromthesecondelectromagnet
136
mayalsoassistthereturnspring72, if a low springpreloadis desiredotherwise,inkeepingthe enginevalve20 seatedduringat leastpart of combustion,
whenthe10pressurein the power cylinder 102 appreciably exceedsthat in the cross-overpassage
110.

If the pneumaticbooster85 includesa bleedmechanismlike the bleedholes
87 in Figure5, the secondelectromagnet
136is an optionalcomponent,,
which canbe
eliminatedif the return spring 72 and other relatedcomponentsare sufhcient for
15

variousfunctions.

The secondelectromagnet136 is indispensable,however, if one is to adopt apneumaticboosterdesignwithout, as shownin Figure4â€ža
bleedmechanism.In thiscase,the secondelectromagnet
136needsto generatean actuationforcein the second
direction to help overcome a high air pressure force from the pneumatic booster

20

during the enginevalve closing,whenthereis no high differentialair pressureforce
on the enginevalve to balancethe force Rom the pneumaticbooster.

In Figures1-5,variousembodimentsof the pneumaticbooster85 arespeciallydevelopedto overcomethe initial pressureforce on the engine-valvefirst surface28
to crack open the engine valve. Yet, through its bleed mechanism,the pneumatic
booster 85 is able to scale down its pressure force for the valve closing when the

differentialpressureforceacrossthe enginevalve headis substantiallysmaller.With
this pneumatic booster 85, the fluid drivers 30 in Figures 1 â€”4 and theelectromagneticdriver 130 in Figure 5 are able to handle the less forceful part of theengine valve opening and closing. The effective integration of the various
30

embodiments of the pneumatic booster 85 is not limited to those fluid andelectromagneticdrivers 30 and 130 discussedabove.In fact, any driver with sufficient
force and control for the engine valve acceleration,deceleration,and seating control

WO 2008/130374

PC T/US2007/021339

LOU-AH30052

will do, with the largeinitial openingforcebeingtakencareof by the pneumatic
booster85.

In all the abovedescriptions,eachof the switchand/orcontrolvalvesmay beeithera single-stage
typeor a multiple-stage
type.Eachvalvecanbeeithera linear
5 type (suchasa spoolvalve)or a rotarytype.Eachvalvecanbedrivenor pilotedby anelectric, electro'magnetic,mechanic,piezoelectric, or fluid means.
In some illustrations and descriptions,the fluid medium may be assumedor

impliedto bein hydraulicor in liquidform. In mostcases,
thesameconcepts
canbe
applied,with properscaling,to pneumaticboostersand systems.As'such,the term
I'0

"fluid" as used herein is meant to include both liquids and gases. Also, in many

illustrationsanddescriptionsso far, the applicationof the inventionis defaultedto be
in split four-strokecycle internal combustionengine valve control, and it is not
limited so. The invention can.be applied to other situations where a fast and/or highinitial-force

control of the motion is needed.

Although the presentinvention has been describedwith referenceto thepreferredembodiments,thoseskilled in the art will recognizethat changesmay bemadein form and detail without departing &om the spirit and scopeof the invention.
As such, it is intended that the foregoing detailed description be regarded as
illustrative rather than limiting and that it is the appended claims, including all20

equivalentsthereof, which are intendedto define the scopeof this invention.

I claim:WO 2008/130374

LOU-AH3

0052

1.
3
4

PC T/US2007/021339-20-

An actuator, comprisinga driverincludinga housing
de6ninga longitudinal
axisandfirst andsecond
directions,andanactuationmechanism
generating
actuationforceat leastin thefirst
direction~

at leastone return spring operablyconnectedwith the actuationmechanism
andbiasingthe actuationmechanismin the seconddirection;andboosteroperablyconnectedwith the actuationmechanism
and8 9biasingathepneumatic
actuationmechanismin the 6rst direction,wherebygivingthe drivera
10

boost force in the first direction.

12

2. The actuatorof claim 1, wherein the pneumaticboosterincluding

13

a pneumaticcylinder;

14

a pneumaticpiston, slideablydisposedin the pneumaticcylinderfor at least

15
16

part of its travel range;anda chargeinechanism,wherebychargingthe pneumaticcylinderandbalancing

17

its pressure
withpressurized
air Boma high-pressure
gassourceduringat leastpartof

18

an enginethermal cycle.

19
20

3. The actuatorof claim 2, wherein the pneumaticboosterfurther including
a bleed mechanism, whereby bleeding off excess air from the pneumatic
cylinder to a low-pressuregas sink during at leastpart of an engine thermal cycle.

24

4. The actuator of claim 2, wherein25

the charge mechanism including a charge ori6ce, whereby substantially26

restricting the chargeQow rate.

27

5. The actuator of claim 2, wherein

the charge mechanismincluding a control mechanism,whereby substantially30

closing off the charge Qow during a substantial portion of a period when the31

pneumaticcylinder is not at its minimum volume.

WO 2008/130374

LOU-AH3

PC T/US2007/021339

0052

6. The actuator of claim 5, wherein:

the actuationmechanismbeingoperablyconnectedwith a loadof the actuator
through a stem;

the controlmechanismof the chargemechanismincludingan ori6ce gateandan undercut on the stem; andthe chargeflow beingopenandclosedwhenthe ori6ce gateandthe undercut
longitudinally overlap and underlap respectively.
7. The actuator of claim 3, wherein".
10

the bleed mechanismbeing at least one bleed passageon the wall of the11

pneumatic
cylinder,whichbecomes
exposedto thepressurized
air in the pneumatic

12

Cylinderwhenthe pneumaticpistontravelsto andbeyonda.prede6neddistancefrom

13

an initial position, wherebybleeding off excessair.

1415

8. The actuator of claim 2, further including

16

a springretaineroperablyconnectingthe at leastone return spring and the17

actuation mechanism, and also functioning as the pneumatic piston.

18

19

9. The actuator of claim 1, wherein20

the driver being a fluid driver;the actuationmechanismcomprising an actuation cylinder, an actuation piston

slideably disposedin the actuationcylinder and dividing the inner volume of theactuationcylinderinto first andsecondfluid spaces,a pistonrod operablyconnectedwith the actuationpiston, and first and secondp'ortsin fluid communication with the25

first and second fluid spaces, respectively.

26

10. The actuator of claim 9, wherein
28
29

the secondport being alternately supplied with high-pressureand low-pressure
fluid lines, through an actuation 3-way valve.

30
31

11. The actuator of claim 9, wherein

the secondport being supplied through a proportional3-way va1ve.

WO 2008/130374

LOU-AH300

PC T/US2007/021339

52

12. The actuator of claim 9, wherein

the first andsecondportsbeingsuppliedthrougha 4-wayvalve.
13. The actuator of claim 9, further including at least one snubber,whereby

substantiallyretardingthevelocityneartheendof thetravelin thesecond
direction.
14. The actuator of claim 1, wherein

the driver being an electromagneticdriver;the actuation mechanism comprising an armature chamber, an armature

10

disposedin the armaturechamber,an armaturerod operablyconnectedwith thearmature, and at least a first electromagneton the first direction side of the armature
13

chamber,whereby being able to pull the armaturein the first direction whenenergized.

15. The actuatorof claim 14, further including a secondelectromagneton thesecond direction side of the armature chamber, whereby being able to pull thearmature in the second direction when energized.
19

16.

20

An engine valve actuator, comprisinga driver including a housing defining a longitudinal axis and first and second
directions, an actuation mechanism generating actuation force at least in the Grst
direction, and a rod operably connected with at least one part of the actuation
mechanismand being moveablealong the longitudinal axis;
an engine valve operably connected with the rod through an engine valve
stem;

at least one return spring operably connectedwith the enginevalve stem andbiasing the engine valve in the seconddirection; anda pneumatic boosteroperablyconnectedwith the enginevalve stem and30

biasing the engine valve in the Qrst direction, whereby giving the enginevalve a boost

31

in the first32

direction.

WO 2008/130374

LOU-AH3

PC T/US2007/021339

0052

17. The engine valve actuatorof claim 16, whereinthe pneumaticbooster
includinga pneumaticcylinder;a pneumatic
piston,slideablydisposedin thepneumatic
cylinderfor at least
part of its travel range; anda chargemechanism,
wherebychargingthepneumatic
cylinderandbalancing
its pressurewith pressurized
air from a high-pressuresource.
18. Theenginevalve actuatorof claim 17,furtherincluding
10

a bleed mechanism, whereby bleeding off excess air from the. pneumatic

cylinderto a low-pressure
gassink duringat leastpartof an enginethermalcycle.
13

19. The engine valve actuator of claim 16, wherein
the driver being a fluid driver;the actuation mechanismcomprising an actuationcylinder, an actuationpiston

17

slideablydisposedin the actuationcylinder and dividing the inner volume of theactuationcylinderinto first and secondfluid spaces,a pistonrod operablyconnectedwith the actuationpiston,and first and secondportsin fluid communication
with thefirst and second fluid spaces, respectively.
J

20. The engine valve actuator of claim 16, wherein
the driver being an electromagnetic driver; and23

the actuation mechanism comprising an armature chamber, an armature24

disposed in the armature chamber, an armature rod operably connected with thearmature,and at least a first electromagneton the first direction side of the armature

26

chamber, whereby being able to pull the armature in the first direction when27

energized.

28

21.
30

The engine valve actuator of claim 20, further including a second

electromagneton the second direction side of the armature chamber,whereby being
able to pull the armaturein the seconddirection when energized.

WO 2008/130374

PC T/US2007/021339-24-

LOU-AH30052

22. A method of controlling an actuatorcomprising(a) providingan actuatorincludingthe following components:a driver further including

a housingdefininga longitudinal
axisandfirst andsecond
directions,an actuationmechanismcapableof geneiatingactuationforceat leastin the first direction, and78

a rodwith oneendoperablyconnectedwith at leastonepart of theactuation mechanism and with the other end available for an

operableconnectionwith a loadof the actuator;
10

at leastonereturnspringoperablyconnectedwith therod andbiasingthe rod
in the second direction;

and

12

a pneumaticbooster further including

13

a pneumatic cylinder,a pneumatic
pistonoperablyconnected
withtherodandbiasingtherod
in the first direction, anda chargemechanism,whereby providing a controlled fluid
communication between the pneumaticcylinder and a highpressure

gas source;19(b) holding the load of the actuatorto a second-directionend position

20

with the force from the at-least-onereturn spring biasing in the second
direction and overcoming the sum of the rest of the forces including those from thepneumaticboosterand the load,
without generatingthe actuation force in the first direction from the actuation
mechanism, and25

with the pneumaticboosterbeing chargedthrough the chargemechanismto
yield a substantialforce in the first direction to opposea substantialload force in thesecond direction;(c) initiating the travel of the load of the actuatorin the first directionby
generatingthe actuationforce in the first directionfrom the actuationmechanism,
30

with the combination of the actuation force and the force from the pneumatic

31

booster being able to overcome the sum of the rest of the forces including thoseWO 2008/130374

LOU-AH30052

PC T/US2007/021339-25-&omthe at-least-one
returnspringandtheloadandaccelerate
theloadin thefirst
direction;(d) continuingthetravelin thefirst directionwith theactuationforcein thefirst direction at least until reaching the target stroke;(e) initiatingthereturntravelof the loadof theactuatorin thesecond
directionat leastby turningoff theactuationforcein thefirst directionsothattheload is accelerated in the second direction at least by the return spring;(f) completingthereturntravelwith a decreasing
forcefrom thereturnspring
andan increasingforcefrom thepneumaticbooster,wherebyslowingdownthe load.
10

23. The method of claim 22, wherein:

13

thepneumaticboosterfurtherincludinga bleedmechanism,
wherebyprovidinga controlledfluid communication
betweenthepneumaticcylinderto a low-14

pressure gas sink.

12

15

24. The method of claim 23, further comprising

bleedingoff excessair in the boostercylinderthroughthe bleed
18

mechanism,during at leastpart of the time period after the initial travel in the first
direction and before near the close of the travel in the second direction, to reduce theforce &om the pneumatic booster.

25. The method of claim 22, wherein:23

the charge mechanisin including a charge orifice, whereby substantiallyrestricting the charge flow rate.

25
26

26. The method of claim 22, wherein:27

the chargemechanismincluding a control mechanism,whereby substantiallyclosing off the charge flow during a substantial portion of a period when the29

pneumaticcylinder is not at its minimum volume.

30
31

27. The method of claim 23, wherein:

WO 2008/130374

PC T/US2007/021339

LOU-AH30052

1 thebleedmechanismbeingat leastonepassageon the wall of the pneumatic

2 cylinder, which becomes
exposedto the pressurized.air
in the pneumatic
cylinder3 when thepneumatic
pistontravelsto andbeyonda predefined
distance
fromaninitial
4 position,

whereby bleeding off excessair.

6 28.

The method of claim 22, wherein

7 thedriver being a fluid driver;

8 theactuation mechanismcomprising an actuation cylinder, an actuationpiston

9 slideably disposedin the actuationcylinder and dividing the inner volume of the
10 actuationcylinderinto first andsecondfluid spaces,andfirst andsecondportsin fluid
11

communicationwith the first and secondfluid spaces,respectively;andthe rod being a pistonrod operablyconnectedwith the actuationpiston.

14

29. The method of claim 22, wherein

15

the driver being an electromagneticdriver;16

the actuation mechanism comprising an armature chamber, an armature

17

disposedin the armaturechamber,and at least a first electromagnet
on the first18

direction side of the armaturechamber,whereby being able to pull the armaturein the

19

first direction when energized; and20

the rod being an armaturerod operably connectedwith the armature.
30. The method of claim 29, further including a secondelectromagneton thesecond direction side of the armature chamber, whereby being able to pull thearmature in the second direction when energized.

WO 2008/130374

PC T/US2007/021339

WO 2008/130374

PC T/US2007/021339

2/5

116~,

L1
102
FlGURE2

WO 2008/130374

PC T/US2007/021339

116

30

90c

FIGURE3

WO 2008/130374

42
4

PC T/US2007/021339

WO 2008/130374

PC T/US2007/021339

5/5
116

86b

FlGU.RE

5