High flow solenoid control valve

An engine oil solenoid actuated control valve includes a molded one-piece member that defines a check valve-receiving region and a coil bobbin region of the solenoid. The check valve-receiving region includes an integral check valve-receiving receptacle associated with an exhaust port of the control valve. A check valve is received in the receptacle. A solenoid armature is received in the coil bobbin region on which a solenoid coil is wound. The molded one-piece member receives a fluid port-forming sleeve member that provides a supply port and control port. A spool valve is received in the port-forming sleeve member and includes a spool valve end connected to the armature of the solenoid. The spool valve includes first and second lands that are moved relative to the respective fluid supply port and control port to control fluid flow at the control port. A fast response, high flow rate is provided by a preselected gap provided between the end of the armature and a pole piece in the bobbin region together with an annular control port configuration.

FIELD OF THE INVENTION
 The present invention relates to an engine oil solenoid control valve for
 controlling oil pressure for valve lifter activation/deactivation.
 BACKGROUND OF THE INVENTION
 Internal combustion engines for motor vehicles are known which include a
 hydraulic system for performing work in addition to lubrication. This work
 can be used to activate/deactivate cylinders of an internal combustion
 engine to conserve fuel. Such a hydraulic valve lifter
 activation/deactivation system can include a hydraulic control valve in a
 valve housing mechanically connected to a separate solenoid. The solenoid
 includes a solenoid coil bobbin on which a wire coil is wound and an
 armature that moves the control valve in response to an input signal (coil
 electrical current signal) to the wire coil to control hydraulic pressure
 in the valve lifter oil control gallery. A separate check valve assembly
 is mounted in a fluid exhaust passage (vent-to-sump) in the engine block
 or cylinder head and functions to maintain oil pressure in the oil control
 gallery at a preselected minimum value. Such engine oil control solenoids
 comprise numerous components which must be assembled together and are
 known to suffer from hydraulic fluid (oil) leakage through various paths
 around the solenoid housing. An object of the present invention is to
 provide an improved engine oil solenoid control valve.
 SUMMARY OF THE INVENTION
 The present invention provides a hydraulic fluid solenoid control valve,
 such as in one embodiment, an engine oil solenoid control valve including
 a molded one-piece member that defines a check valve-receiving region and
 a coil bobbin region of the solenoid. The check valve-receiving region
 includes an integral check valve-receiving receptacle associated with an
 exhaust port of the control valve. A check valve is received in the
 receptacle. A solenoid armature is received in the coil bobbin region on
 which region a solenoid coil is wound.
 In a particular embodiment of the invention, the molded one-piece member
 includes an end proximate the check valve-receiving region that receives a
 fluid port-forming sleeve member that provides a supply port and control
 port. A spool valve is received in the port-forming sleeve member and
 includes a spool valve end connected to the armature of the solenoid. The
 spool valve moves in response to movement of the solenoid armature in
 response to electrical current signals supplied to the solenoid coil. The
 spool valve includes first and second lands that are moved relative to the
 respective fluid supply port and control port to control fluid flow at the
 control port.
 In a preferred embodiment of the invention, a fast response, high flow rate
 is provided by a preselected gap provided between the end of the armature
 and a pole piece in the coil bobbin region together with an annular
 control port configuration and cylindrical spool lands. The preselected
 gap in turn defines a spool valve open position relative to the control
 port where, at the valve open position, a flow area is provided to the
 control port equal to the circumference of the annular control port
 configuration multiplied times the gap distance by which the spool land
 opens at the control port.
 The foregoing and other objects, features, and advantages of the invention
 will become apparent from the following more detailed description taken
 with the accompanying following drawings.

DESCRIPTION OF THE INVENTION
 Referring to FIGS. 1-2, an engine oil solenoid control valve 10 pursuant to
 an illustrative embodiment of the invention is shown including a molded
 one-piece check valve nozzle and bobbin member 12 forming a check
 valve-receiving region 13 and a coil bobbin region 15. The member 12 can
 be injection or otherwise molded of a moldable thermoplastic material,
 such as the high temperature rated, glass fiber reinforced thermoplastic
 material (e.g. Amodel A1133HS material available from Amoco Polymers,
 Inc.), or other suitable moldable material.
 The molded one-piece member 12 includes an open end 12a proximate the check
 valve-receiving region 13 that receives a tubular fluid port-forming metal
 (e.g. aluminum) sleeve member 17 that provides a pair of diametrically
 opposite supply ports SP and diametrically opposite control ports CP on
 the sleeve member 17. A fluid seal S is provided between the sleeve member
 17 and the inner wall 12w of the open end 12a. The outermost end of the
 sleeve member 17 is sealed closed by a plug or plate 21. A spool valve 19
 is received in a cylindrical axial bore of port-forming sleeve member 17
 and includes a spool valve end 19a connected to a solenoid armature 52.
 The spool valve 19 moves in response to movement of the solenoid armature
 52 in response to electrical current signals supplied to the solenoid coil
 50. The spool valve 19 includes first and second cylindrical sealing
 surfaces or lands 19b, 19c that are moved relative to the respective fluid
 supply ports SP and control ports CP to control fluid flow at the control
 ports. The spool valve 19 may include additional lands (not shown) to
 prevent binding of the spool valve 19 in the axial bore of sleeve member
 17. Annular fluid filters F can be provided in annular grooves on the
 sleeve member 17 for the supply ports SP and control ports CP. The control
 ports CP are communicated to one another by an annular recessed control
 port chamber or region R extending circumferentially about the inner wall
 W of the sleeve member 17 and relative to which the spool land 19c moves
 to open or close the control port chamber or region R as described below.
 The supply ports SP are communicated to a source of hydraulic fluid
 pressure, such as a main engine oil pressure port shown schematically as
 P, in an internal combustion engine block or cylinder head. The control
 ports CP are communicated to a control passage 32 that supplies hydraulic
 fluid to an oil control gallery (not shown) of a hydraulic valve lifter
 activation/deactivation circuit provided in the engine block or engine
 cylinder head (not shown).
 A longitudinal armature bore or passage 26 is defined in part in the region
 13 and communicates to a check valve 30 residing in a receptacle 28 formed
 in boss 29 that is molded integrally on the member 12. The receptacle 28
 defines an exhaust port EP. Passage 26 communicates to the axial bore of
 sleeve member 17. The check valve 30 includes annular cap 30a that is held
 in the receptacle 28 by heat stacking or ultrasonic welding and a ball
 check valve 30b made of steel (e.g. type 440C steel) and located between a
 biasing spring 30c and ball valve seat 30d. Ball valve seat 30d can be
 formed integral to member 12 by molding or comprise a separate insert in
 the nozzle region. The check valve 30 communicates to an exhaust passage
 31 of the hydraulic valve lifter activation/deactivation circuit. The
 check valve 30 is provided at the exhaust port EP to prevent oil pressure
 in the oil control gallery (not shown) of the hydraulic valve lifter
 activation/deactivation circuit from falling below a preselected minimum
 oil pressure value such as, for example only, 3 psi, when the hydraulic
 valve lifter activation/deactivation system is deactivated.
 The spool valve 19 includes a longitudinal bore or passage 19d that
 communicates at one end to a radial bore 19e that in turn communicates to
 the axial bore of sleeve member 17 and armature bore 26. At the other
 opposite end 19f of the spool valve, the passage 19d communicates to any
 hydraulic fluid that leaks from the supply port SP past land 19b so as to
 fluid pressure balance the spool valve 19.
 The region 13 and sleeve member 17 include respective first and second
 O-ring seals 44, 42 that are disposed in a circumferential groove molded
 integrally in the member 12 and a circumferential groove formed in sleeve
 member 17. Seals 44, 42 mate with walls W2, W1 of a fluid control passage
 32 of a hydraulic valve lifter activation/deactivation circuit provided in
 the engine block or engine cylinder head (not shown) with the control
 passage 32 supplying hydraulic fluid to the oil control gallery. A third
 O-ring seal 46 is provided in a circumferential groove molded integrally
 on larger diameter region 13 of member 12 and together with O-ring 44 mate
 with walls W3, W2 of a fluid exhaust passage 31 of a hydraulic valve
 lifter activation/deactivation circuit provided in the engine block or
 engine cylinder head (not shown) with fluid exhaust passage 31 providing
 for return of hydraulic fluid to a low pressure sump. As mentioned above,
 check valve 30 is provided at the exhaust port EP to prevent oil pressure
 in the oil control gallery of the hydraulic valve lifter
 activation/deactivation circuit from falling below a preselected minimum
 oil pressure value such as, for example only, 3 psi, when the valve lifter
 activation/deactivation system is deactivated.
 In particular, at the closed spool valve position of FIG. 1, the control
 land 19c does not completely close off the region R of control ports CP
 such that there is a preselected underlap (gap) L of the land 19c at
 region R of control ports CP (e.g. 0.003 inch gap) controlled by bias of
 armature spring 72 and effective to provide a 3 psi hydraulic pressure at
 control ports CP and at check valve 30 in armature bore 26 in the closed
 spool valve position when the valve lifter activation/deactivation system
 is deactivated. The underlap L communicates the control ports CP and
 armature bore 26 to supply port SP enough to provide the 3 psi fluid (oil)
 pressure at control ports CP and check valve 30. The underlap L is
 controlled by bias of armature spring 72. As an example of the 3 psi
 underlap, if there is 20 psi hydraulic pressure at the supply port SP, a 3
 psi hydraulic pressure can be provided by underlap L at the control ports
 CP and check valve 30, which opens, as necessary, to allow fluid flow
 through exhaust port EP to maintain 3 psi in the oil control gallery that
 is communicated to control ports CP. The check valve 30 thus opens against
 bias of spring 30c as necessary to maintain a 3 psi (or other) oil
 pressure at the control ports and the oil control gallery when the valve
 lifter activation/deactivation system is deactivated.
 The coil bobbin region 15 includes an electromagnetic wire coil 50
 (partially shown) wound on bobbin sleeve 15a along the length thereof
 between annular bobbin end walls 15b. The coil 50 is connected to a source
 of input signals, such as an engine electronic control (EEC) module (not
 shown), that provides electrical current signals to the coil 50 to control
 movement of an armature 52 that, in turn, controls the position of a spool
 valve 19 between the closed/open valve positions (on/off) to control
 hydraulic pressure in the valve lifter oil control gallery. The solenoid
 coil 50 receives the current signals via electrical connectors 54a, 54b
 that reside in a molded connector housing 57 disposed on member 12 and
 that are connected to the coil. The connectors 54a, 54b are connected to
 the signal source (EEC module).
 The spool valve 19 is moved between the valve closed position, FIG. 1, and
 valve open position, FIG. 2, in response to electrical current signals
 supplied to solenoid coil 50 from the EEC module (not shown). The spool
 valve 19 is moved to the open position to activate the hydraulic valve
 lifter activation/deactivation system (not shown) and to the valve closed
 position to deactivate the hydraulic valve lifter activation/deactivation
 system.
 A simple generally cylindrical armature rod 53 can be used as the armature
 52 in an embodiment of the present invention that further includes molded
 integral arcuate recesses 56 in bore 26. The recesses 56 extend radially
 into the armature bore 26 on diametrically opposite sides of the bore 26
 and along the axis of bore 26 to provide axial paths for hydraulic fluid
 on opposite lateral ends of the armature 52 to eliminate any imbalanced
 hydraulic pressures acting thereon (hydraulic lock condition where the
 armature would remain in open or closed positions) as further described in
 U.S. application entitled "SOLENOID CONTROL VALVE" (Ser. No. 09/479,415,
 now U.S. Pat. No. 6,209,563) of common inventorship herewith, the
 teachings of which are incorporated herein by reference. The armature rod
 53 typically is made of ferrous material such as steel. A simple, low cost
 armature rod 53 can be used without the need for a complex geometry
 armature.
 The armature 52 includes an axial end bore 52b in which the end 19a of the
 spool valve 19 is pressed in interference fit to a preselected axial
 dimension dictated by the depth of bore 52b. This controlled dimension of
 the spool valve end in the armature bore 52b permits close control of the
 axial gap G provided between ferromagnetic armature 52 and a ferromagnetic
 (e.g. steel) pole piece 62 without the need for a calibration of the axial
 gap. The pole piece 62 is disposed in an end bore of the coil bobbin
 region 15 by radially compressive forces of O-ring 74 disposed on the pole
 piece.
 In a preferred embodiment of the invention, a fast response, high flow rate
 control valve is provided by preselected gap G provided between the end of
 the armature 52 and pole piece 62 in the bobbin region 15 together with
 annular circumferentially recessed control port chamber or region R. The
 preselected gap G in turn defines a spool valve open position, FIG. 2,
 relative to the control port chamber or region R where, at the open valve
 position, a flow area is provided to control ports CP equal to the
 circumference of the annular recessed control port chamber or region R
 multiplied times the gap axial distance G' by which the spool land 19c
 opens at the control port chamber or region R as a result of the armature
 end closing the gap G, FIG. 2, when the appropriate electrical current
 signals are supplied to the solenoid coil 50.
 The solenoid can or housing 64 typically is made of steel or other
 magnetically permeable material and includes an axial end flange 64b to
 axially retain the pole piece 62. The solenoid housing 64 is joined to the
 member 12 by circumferential or radial tabs 64a crimped to overlie the end
 wall 15w of the coil bobbin region 15 and the flux washer 80. Tabs 64a are
 shown prior to crimping in FIGS. 1-2.
 A steel flux washer 80 is disposed on the member 12 in a position to
 concentrate magnetic flux at the armature 52 residing in the armature bore
 26. The washer 80 extends about approximately 85% of the periphery of the
 armature 52.
 The pole piece 62 is provided with a controlled axial dimension blind bore
 62a that receives the end of the spring 72 to avoid the need to calibrate
 the spring preload using a set screw.
 The engine oil solenoid control valve of the invention can be used to
 control oil pressure in the oil control gallery of an internal combustion
 engine as part of a hydraulic valve lifter activation/deactivation system.
 The engine oil solenoid control valve can be made pursuant to a method of
 the invention by assembling the various solenoid components described
 above in the molded one-piece check valve nozzle and coil bobbin member.
 Although certain preferred embodiments of the invention have been shown and
 described in detail, it should be understood that variations or
 modifications may be made without departing from the spirit or scope of
 the present invention.