Having Means To Produce Proportional Flow Patents (Class 251/129.08)
  • Publication number: 20030201414
    Abstract: An extended range proportional valve which can control rates of mass flow over continuous low, intermediate and high ranges has a pilot member mounted on an armature of a solenoid which can be dithered onto and off of a pilot opening in a main valve member which seals a main valve opening to control mass flow rates over the low range by varying the duty cycle and/or frequency of a pulse width modulated current in the solenoid coil. Intermediate and high flow rates are achieved by dithering the pilot valve member with a duty cycle and/or frequency sufficient to raise the main valve member relatively short and relatively long respective distances from the main valve seat.
    Type: Application
    Filed: May 19, 2003
    Publication date: October 30, 2003
    Applicant: ASCO Controls, L.P.
    Inventors: Paul W. Freisinger, John J. Haller, Peter A. Holborow
  • Patent number: 6619615
    Abstract: A proportional pressure control valve is described capable of serving as a pilot, servo or direct control valve and having a pressure reducing function and a pressure maintaining function. The valve is comprised essentially of a valve housing (2) with inlet and outlet ports (4, 5, 6), a control element (7), an armature rod (8) and a proportional magnet (3). The proportional magnet (3) is an assembly of a magnet core (10), a magnet armature (11) and a magnet coil (12), whereby the proportional magnet (3) when in its range of operation possesses a nearly constant magnetic strength. In accord with the invention, when in a holding position of the magnetic armature (11) the smallest possible gap (13) exists between the magnet armature (11) and the magnet core (10).
    Type: Grant
    Filed: July 26, 2001
    Date of Patent: September 16, 2003
    Assignee: ZF Friedrichshafen AG
    Inventors: Karlheinz Mayr, Markus Eisele, Thilo Schmidt, Walter Kill, Hubert Remmlinger, Jochen Fischer, Robert Ingenbleek
  • Patent number: 6607176
    Abstract: A proportional pressure control valve serves as a direct control valve with a pressure reducing function and a pressure holding function. The valve, includes a valve housing (2) with inlet and outlet . ports (4, 5, 6), a control element (7) which has a feedback facility, an armature rod (15) and a proportional magnet (3). The proportional magnet is comprised of a magnet core (17), a magnet armature (16) and a magnet coil (18), wherein this proportional magnet (3) in its operational range possesses a nearly constant magnetic force. In accordance with the invention, in a holding position of the magnet armature (16), the smallest axial space (21) between the magnet armature (16) and the magnet core (17) is so dimensioned, first, that the magnetic force between these two components (16, 17) when in the holding position is greater than the magnetic force in the operational zone of the proportional magnets (3), and second, that the magnet armature (16) can be fixed in the holding position by this magnetic force.
    Type: Grant
    Filed: June 20, 2001
    Date of Patent: August 19, 2003
    Assignee: ZF Friedrichshafen AG
    Inventors: Karlheinz Mayr, Markus Eisele, Walter Kill, Michael Weber, Hubert Remmlinger, Jochen Fischer
  • Publication number: 20030146402
    Abstract: To provide a small-sized and low-cost proportional solenoid valve which is capable of controlling a bidirectional fluid flow. A core is fixed in a pipe, and a hollow shaft having an extreme end thereof closed by a valve seat and a portion adjacent thereto formed with valve holes is fixed in the core. Within the pipe, there are arranged a hollow cylindrical valve element axially movable using the shaft as a guide and urged in a direction away from the core by a spring, for opening and closing the valve holes, and a plunger, while outside the pipe, there is arranged a solenoid coil. The proportional solenoid valve has a body formed by the pipe, and the component parts for opening and closing the valve are arranged within the pipe, so that it is possible to reduce the size of the proportional solenoid valve, the number of component parts, and machining costs and material costs, which contributes to reduction of costs of the valve.
    Type: Application
    Filed: December 2, 2002
    Publication date: August 7, 2003
    Applicant: TGK Co., Ltd.
    Inventors: Hisatoshi Hirota, Tokumi Tsugawa, Katsumi Koyama, Toshiyuki Shiota, Yuusuke Inoue
  • Patent number: 6543744
    Abstract: A solenoid valve includes an outlet tube and a plunger stop. A plunger is slidably disposed within the solenoid valve between the outlet tube and the plunger stop. The plunger is movable between a closed position wherein the plunger engages the outlet tube to block fluid flow through an outlet passage formed in the outlet tube and an open position wherein the plunger is distanced from the outlet tube to permit fluid flow through the outlet passage. The solenoid valve also includes a coil that is energizable to bias the plunger between the closed position and the open position. The plunger stop is configured so that the magnitude of the force of attraction between the plunger and the plunger stop is linearly proportional to the magnitude of the current applied to the coil. Moreover, the magnitude of the force of attraction between the plunger and the plunger stop is independent of the position of the plunger.
    Type: Grant
    Filed: June 15, 2001
    Date of Patent: April 8, 2003
    Assignee: Delphi Technologies, Inc.
    Inventors: Conrado Carrillo, Lorenzo Guadalupe Rodriquez, Yingjie Lin, Jean-Francois Pelka, Amiyo K. Basu
  • Publication number: 20020190234
    Abstract: A solenoid valve includes an outlet tube and a plunger stop. A plunger is slidably disposed within the solenoid valve between the outlet tube and the plunger stop. The plunger is movable between a closed position wherein the plunger engages the outlet tube to block fluid flow through an outlet passage formed in the outlet tube and an open position wherein the plunger is distanced from the outlet tube to permit fluid flow through the outlet passage. The solenoid valve also includes a coil that is energizable to bias the plunger between the closed position and the open position. The plunger stop is configured so that the magnitude of the force of attraction between the plunger and the plunger stop is linearly proportional to the magnitude of the current applied to the coil. Moreover, the magnitude of the force of attraction between the plunger and the plunger stop is independent of the position of the plunger.
    Type: Application
    Filed: June 15, 2001
    Publication date: December 19, 2002
    Inventors: Conrado Carrillo, Lorenzo Guadalupe Rodriguez, Yingjie Lin, Jean-Francois Pelka, Amiyo K. Basu
  • Patent number: 6481332
    Abstract: In a solenoid-controlled valve assembly a biasing means (21) is adapted to apply a resisting force to a spool (22) in a direction opposite to the direction substantially of a force applied by an armature (14), and engagement between at least one of the spool and the biasing means and the spool and the armature is through an engagement means defining a single point of contact. The spool (22) may be provided with at least one land adapted to connect and disconnect two flow passages (6, 8), and the first ends of the two passages are spaced apart in a direction parallel to the axis of the bore by a smaller distance than the spacing between the second ends of the passages.
    Type: Grant
    Filed: March 23, 2001
    Date of Patent: November 19, 2002
    Assignee: Lucas Industries Limited
    Inventor: Robert Alan Anderson
  • Publication number: 20020117644
    Abstract: A solenoid valve includes a plunger that includes a conical plunger tip and an outlet tube that is formed with an outlet passage. The outlet passage includes a first frusto-conical portion into which the plunger tip fits. The plunger is movable between a closed configuration wherein the plunger engages the outlet tube to block fluid flow through the outlet passage and an open configuration wherein the plunger is distanced from the outlet tube to permit fluid flow through the outlet passage. As the plunger moves, there is only one restriction of flow between the plunger and the outlet tube for each position of the plunger. As such, the flow through the valve is linear with respect to the motion of the plunger and the solenoid valve can be used to easily and accurately control the flow rate of fluid therethrough.
    Type: Application
    Filed: February 26, 2001
    Publication date: August 29, 2002
    Inventors: Conrado Carrillo, Lorenzo Guadalupe Rodriguez, Jean-Francois Pelka
  • Patent number: 6435472
    Abstract: Proportional variable force solenoid valve for controlling the pressure of a fluid in a fluid control system comprises a solenoid housing having therein a solenoid coil, an armature movable in response to electrical current applied to the solenoid coil, and a biasing spring for biasing the armature in a direction to establish a valve fluid pressure response to solenoid coil current. An inner armature end cooperates with or engages a damping member residing in a fluid damping chamber to reduce non-linear valve responses resulting from pressure oscillations in the fluid control system.
    Type: Grant
    Filed: April 25, 2001
    Date of Patent: August 20, 2002
    Assignee: Saturn Electronics & Engineering, Inc.
    Inventors: Hamid Najmolhoda, David L. Seid, David A. Nezwek, John A. Cruden, Jr.
  • Patent number: 6435213
    Abstract: A pressure control valve with a hydraulic system of an automatic transmission for a motor vehicle includes a valve body defining a control chamber, fluid ports communicating with the control chamber, and a valve spool having spaced pressure control lands located in the control chamber, the valve spool urged by a compression spring in an opposite direction from an electromagnetic force developed on the spool when a solenoid is energized. In one embodiment a control land is formed with a pressure feedback orifice that communicates a control port with a feedback chamber. The valve spool can be formed with different sized control lands. The feedback orifice is substantially insensitive to fluid temperature variation.
    Type: Grant
    Filed: April 23, 1999
    Date of Patent: August 20, 2002
    Assignee: Visteon Global Technologies, Inc.
    Inventor: Zheng David Lou
  • Patent number: 6419478
    Abstract: An apparatus for and method for controlling the gas supply of a gas appliance. The gas appliance has a main burner with a main valve controlled by a linear actuator. A stepper motor positions the linear actuator under control of a microprocessor. The stepper motor and microprocessor are powered from a thermopile having its output converted to the appropriate voltages by a DC-to-DC converter. Changes in valve position permit changes of fuel type and flame intensity.
    Type: Grant
    Filed: November 23, 1999
    Date of Patent: July 16, 2002
    Assignee: Honeywell International Inc.
    Inventor: Stephen J. Kemp
  • Patent number: 6397891
    Abstract: A hydraulic control valve has a solenoid with a coil having an interior. The solenoid also has a pole shoe inserted partially into the interior of the coil, wherein the interior of the coil defines an armature chamber and wherein the pole shoe delimits the armature chamber axially. The solenoid also has an armature arranged in the armature chamber and moveable in the armature chamber relative to the coil. The solenoid further has an armature plunger connected to the armature, wherein the pole shoe has a central bore and wherein the armature plunger is received in the central bore and penetrates the pole shoe. A hydraulic part with a valve housing formed as a mounting bushing and resting against the pole shoe is provided. The valve housing has an axial valve bore. The hydraulic part also has a low pressure area surrounding the valve housing, wherein the valve housing has at least one radial bore connecting the axial valve bore with the low pressure area.
    Type: Grant
    Filed: August 11, 2000
    Date of Patent: June 4, 2002
    Assignee: Hydraulik Ring GmbH
    Inventors: Rolf Neuhaus, Bernd Urlaub, Friedrich Zapf, Liebhart Zaiser
  • Patent number: 6390129
    Abstract: A device for metering pressurized fluid in proportion to a supplied input signal to a solenoid provides non-proportional magnetic flux rectified by a piece-wise non-linear spring assembly. The non-linear spring assembly includes a pair of flexure springs each with four independent spring fingers. The spring fingers supply a plurality of piece-wise forces opposing movement of the armature caused by magnetic flux generated by an electromatic coil to provide a non-proportional opposing force the non-proportional force of the magnetic flux. This allows the metering valve to be moved, and thereby fluid metered, in proportion to the input signal supplied to the coil. A position transducer can be coupled the armature to provide valve position feedback to an electronic control unit for correcting deviations in the actual position of the valve.
    Type: Grant
    Filed: December 14, 2000
    Date of Patent: May 21, 2002
    Assignee: Jansen's Aircraft Systems Controls, Inc.
    Inventors: Harvey B. Jansen, Craig S. Jansen
  • Patent number: 6386220
    Abstract: A solenoid operated pressure control valve of the type using a spool valve member for controlling flow from a source inlet to a control outlet port and to an exhaust port. The solenoid has a reduced area portion of the flux collector in magnetic loop forming an annular air gap remote from the working air gap. The reduced flux across the annular air gap compensates for the rapid flux increase as the working air gap closes.
    Type: Grant
    Filed: May 22, 2000
    Date of Patent: May 14, 2002
    Assignee: Eaton Corporation
    Inventor: Anthony G. Koenings
  • Publication number: 20020053652
    Abstract: An extended range proportional valve which can control rates of mass flow over continuous low, intermediate and high ranges has a pilot member mounted on an armature of a solenoid which can be dithered onto and off of a pilot opening in a main valve member which seals a main valve opening to control mass flow rates over the low range by varying the duty cycle and/or frequency of a pulse width modulated current in the solenoid coil. Intermediate and high flow rates are achieved by dithering the pilot valve member with a duty cycle and/or frequency sufficient to raise the main valve member relatively short and relatively long respective distances from the main valve seat.
    Type: Application
    Filed: February 18, 2000
    Publication date: May 9, 2002
    Inventors: Paul W. Freisinger, John J. Haller, Peter A. Holborow
  • Patent number: 6378545
    Abstract: An electromagnetically actuable proportional hydraulic valve (10) is described, which is distinguished in particular by a constant, low-wear operating performance. This is attained by means of a closing member (60) having an approximately conical sealing body (60c, 70) with a curved dome-like face end oriented toward the valve seat (58). The sealing body (60c, 70) together with the valve seat (58) forms a conical seat valve. The sealing body of the closing member (60) is provided with a flow separation edge (60d), which improves the temperature sensitivity of the proportional valve (10).
    Type: Grant
    Filed: July 7, 2000
    Date of Patent: April 30, 2002
    Assignee: Robert Bosch GmbH
    Inventors: Aytekin Bozkan, Tilo Hofmann, Christof Ott
  • Patent number: 6371441
    Abstract: A fuel injection valve, including a valve member which can control the opening and closing of a fuel outlet opening, an actuating mechanism which can move the valve member, and a compensation device which can exert compensation forces on the valve member that counteract an opening stroke of the valve member, wherein the compensation device has a piston which is supported so that it can move in an associated cylinder, wherein at one end, the piston defines a hydraulic chamber in the cylinder, which is acted on with a reference pressure, and in a starting position, the piston is supported at the other end against a stop that is stationary in relation to the cylinder, and via a force transmission mechanism, the valve member can drive the piston out of its starting position away from the stop. In this manner valve operation should be improved with regard to its controllability.
    Type: Grant
    Filed: December 7, 2000
    Date of Patent: April 16, 2002
    Assignee: Robert Bosch GmbH
    Inventor: Patrick Mattes
  • Patent number: 6367766
    Abstract: A proportional flow valve wherein a solenoid assembly moves an armature assembly towards a valve seat in proportion to the flow of current through the solenoid assembly. The armature assembly abuttingly engages a seal to hold the seal away from the valve seat at a distance correspondingly proportionally related to the applied current. In this manner, the seal is movable towards and away from the valve seat among a fully open position, a closed position, and partially open positions therebetween. A spring assembly biases the seal towards the valve seat and, when the solenoid assembly is energized, the armature assembly allows the spring assembly to seat the seal against the valve seat to place it in the closed position.
    Type: Grant
    Filed: May 3, 2000
    Date of Patent: April 9, 2002
    Inventors: Robert Briant, Wayne Pascoal, James A. Burns
  • Patent number: 6364281
    Abstract: A solenoid operated valve is controlled upon increasing energization for greater flow by incrementing by a small fraction of the maximum current a target current level for the desired flow for a short duration followed by energization at the target level. Upon decreasing energization for lesser flow, the valve is energized at a target current decremented by a small fraction of the maximum current for a short duration. The result is a nearly negligible hysteresis.
    Type: Grant
    Filed: March 22, 2000
    Date of Patent: April 2, 2002
    Assignee: Eaton Corporation
    Inventors: Daniel L. DeLand, Andrew W. Westergaard, Kenneth J. Parker, Roger L. Kennedy, Jr.
  • Publication number: 20020027213
    Abstract: A method for operating a proportional flow valve with a pilot valve member over an extended range and at a low flow rate. The pilot valve member may be operated, by varying the frequency or duty cycle or both of the pulse width modulated current applied to the solenoid, without thereby causing the main valve member to open.
    Type: Application
    Filed: July 12, 2001
    Publication date: March 7, 2002
    Inventor: Davis K. Jensen
  • Publication number: 20020017624
    Abstract: A method for controlling a solenoid using a single coil solenoid for both course and fine adjustment. A resistor or series of resistors may be used in parallel/for current controlled solenoids or in series for voltage controlled solenoids for allowing course or finite control of the solenoids.
    Type: Application
    Filed: June 19, 2001
    Publication date: February 14, 2002
    Inventors: Bradley C. Erickson, Garrett R. Holmes, Steven J. Roskowski
  • Publication number: 20010032947
    Abstract: An extended range proportional valve which can control rates of mass flow over continuous low, intermediate and high ranges has a pilot member mounted on an armature of a solenoid which can be dithered onto and off of a pilot opening in a main valve member which seals a main valve opening to control mass flow rates over the low range by varying the duty cycle and/or frequency of a pulse width modulated current in the solenoid coil. Intermediate and high flow rates are achieved by dithering the pilot valve member with a duty cycle and/or frequency sufficient to raise the main valve member relatively short and relatively long respective distances from the main valve seat.
    Type: Application
    Filed: May 17, 2001
    Publication date: October 25, 2001
    Inventors: Paul W. Freisinger, John J. Haller, Peter A. Holborow
  • Patent number: 6293514
    Abstract: A valve including a cylindrical bore having a circular seat at one end thereof, a valve member that is movable in the axial direction of the seat, and control means connected to the valve member, the valve member including a first portion which serves as a closure element, and a second portion which is engaged in the bore and which is shaped to regulate the flow of the fluid at a desired rate depending on the axial position of the valve member, the second portion of the valve member is detached from the first portion and has a cylindrical outside surface of diameter such that it is in sliding contact with the cylindrical surface of the bore; at least one recess is formed in the cylindrical outside surface of the second portion of the valve member so as to define a passage having a predefined shape, and means is provided for permanently holding the two portions of the valve member in mutual contact so that they are displaced axially simultaneously under the action of the control means.
    Type: Grant
    Filed: July 20, 2000
    Date of Patent: September 25, 2001
    Assignee: A. Theobald SA
    Inventors: Christophe Pechoux, Claude Villermaux
  • Patent number: 6269827
    Abstract: A variable force solenoid operated pressure control valve for controlling an hydraulically operated actuator in a fluid pressure circuit. The valve has a spool in a straight spool bore with fluid pressure chambers at opposite ends. One spool end has a rod press fitted therein with the rod extending through the fluid pressure chamber and operatively contacting the solenoid armature. The rod creates an area differential on the spool ends for providing an axial spool force proportional to the pressure in the fluid chambers which are each connected by a metering passage in the spool to a recess on the spool which is continuously connected to a control pressure port. A supply port is connected to the recess by a first valving land on the spool and an exhaust port is connected to the recess by a second valving land on the spool. The metering passages serve to attenuate transients.
    Type: Grant
    Filed: October 7, 1999
    Date of Patent: August 7, 2001
    Assignee: Eaton Corporation
    Inventor: James C. Potter
  • Patent number: 6247765
    Abstract: In controlling the fluid pressure applied to a load using a proportional fluid pressure control valve or a flow control valve, responsiveness of control is improved in a pressure region where the consumption of fluid is larger than in other regions. In this method, if there is a pressure region where the consumption of fluid is greater than in other regions, overshoot control is carried out to increase fluid pressure in such a pressure region by adding a predetermined pressure to a target pressure for a predetermined time, or undershoot control is carried out to reduce fluid pressure in such a pressure region by subtracting a predetermined pressure from a target pressure for a predetermined time. It is thus possible to increase and reduce fluid pressure quickly to a target pressure even in a pressure region where the consumption of fluid is large.
    Type: Grant
    Filed: September 15, 1998
    Date of Patent: June 19, 2001
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Hitoshi Oyama
  • Patent number: 6223761
    Abstract: Proportional variable force solenoid valve for controlling pressure of a fluid in a fluid control system comprises a solenoid housing having therein a solenoid coil, an armature movable in response to electrical current applied to the solenoid coil, and a biasing spring for biasing the armature in a direction to establish a valve fluid pressure response to solenoid coil current. An inner armature end cooperates with or engages a damping member residing in a fluid damping chamber to reduce non-linear valve responses resulting from pressure oscillations in the fluid control system.
    Type: Grant
    Filed: November 1, 1999
    Date of Patent: May 1, 2001
    Assignee: Saturn Electronics & Engineering, Inc.
    Inventors: Hamid Najmolhoda, David L. Seid, David A. Nezwek, John A. Cruden, Jr.
  • Patent number: 6220569
    Abstract: An electrically controlled proportional valve provides for precise control of fluid flow using an armature which is positioned at the center of a spider. The armature is supported and biased axially by a plurality of springs that radiate outwardly from it. The springs support the armature for elastic movement in the axial direction, and hold it biased against a first port, so that the armature functions as a valve element, which normally closes that port. A magnet coil is positioned so that when energized it applies force to the armature, overcoming the bias of the springs and drawing the armature away from the first port. During armature movement the plurality of springs are deflected at their outer diameter against an angled surface on the valve case. The increased spring surface area that rests against the valve case causes a proportional relationship between the movement of the armature and the magnetic field created by the magnet coil.
    Type: Grant
    Filed: January 7, 2000
    Date of Patent: April 24, 2001
    Assignee: Clippard Instrument Laboratory, Inc.
    Inventor: Edmund F. Kelly
  • Patent number: 6220275
    Abstract: The solenoid valve (10) has an armature chamber (38) communicated with the outlets (86) of the valve to receive feed of fluid. The fluid in the chamber (38) is drained through drain passages (96) which are arranged to open into the chamber (38) at a location radially outwardly offset from the axis of the valve. The flow of fluid flowing into the chamber (38) is directly transferred to the drain passages (96) to thereby wash ferrous particles away from the magnetic gap to self-clean the gap each time the valve is opened. A spacer (62) made of a non-magnetizable material covers the upper end face of the armature (36) to prevent accumulation of ferrous particles.
    Type: Grant
    Filed: May 25, 1999
    Date of Patent: April 24, 2001
    Assignee: NOK Corporation
    Inventors: Hiroyuki Nishinosono, Norio Uemura, Nobuyuki Oka
  • Patent number: 6202697
    Abstract: A proportional pressure control valve of the type in which a spool is driven by an electromagnet to control the load pressure to a value corresponding to the electromagnet energizing current is provided to simplify and reduce the cost of such valve. The number of springs has been reduced to one by biasing the spool with a spring through an actuating element of the electromagnet. Also, by providing a reaction force piston near a low-pressure pressure chamber, the need to form a hole in the actuator at a functionally important portion has been eliminated. Furthermore, arrangement is such that the load pressure acts on the spool in the same direction with the force of the electromagnet to supplement it. Further, the actuating element is formed integrally with the spool to eliminate any sliding portions from the actuating element, and a gap is formed between the actuation element and the member surrounding the actuating element to reduce the sliding resistance thereof.
    Type: Grant
    Filed: November 9, 1999
    Date of Patent: March 20, 2001
    Assignee: Sumitomo Electric Industries, Inc.
    Inventors: Hitoshi Oyama, Koichi Hashida
  • Patent number: 6179005
    Abstract: A spool valve type electromagnetic valve constructed to facilitate production at reduced cost includes a linear solenoid having a spool and a plunger that are coaxially aligned. The linear solenoid also has a rear yoke which is configured by a resin-made bobbin around which a coil is wound and a plunger movably fitted in the resin made bobbin. The linear solenoid also includes a front yoke positioned in the bobbin in coaxial alignment with both the rear yoke and a connecting end of a valve body of the valve. The front yoke, the rear yoke and the resin-made bobbin form an integrated structure produced through insert molding. An alignment facilitating portion is provided between the front yoke and the valve body.
    Type: Grant
    Filed: October 22, 1999
    Date of Patent: January 30, 2001
    Assignee: Aisin Seiki Kabushiki Kaisha
    Inventor: Madoka Inami
  • Patent number: 6179268
    Abstract: A proportional variable force solenoid fluid control valve for controlling the pressure of a pressurized fluid in a fluid control system in proportion to the current level of an electrical input signal includes an armature in engagement with a fluid pressure control valve and movable in response to electrical current applied to a solenoid disposed on a coil bobbin in a solenoid housing and a coil spring for biasing the armature in a direction to establish a valve fluid pressure response to current level supplied to the solenoid. A plurality of axially magnetized permanent magnet segments each having an inner arcuate magnet surface facing the armature are provided to collectively provide a permanent magnetic field that cooperates with the electromagnetic field of the energized coil to move the armature.
    Type: Grant
    Filed: April 21, 1998
    Date of Patent: January 30, 2001
    Assignee: Saturn Electronics & Engineering, Inc.
    Inventor: David L. Seid
  • Patent number: 6170506
    Abstract: A method for cleaning a solenoid-operated regulator valve wherein command current applied to a solenoid actuator establishes a defined response of a valve. Cleaning current pulses applied to the solenoid establish a response that does not interfere with the effectiveness of the valve function. The pulse width, pulse amplitude, pulse direction and pulse period are determined by the degree of contamination of the valve environment.
    Type: Grant
    Filed: February 8, 1999
    Date of Patent: January 9, 2001
    Assignee: Ford Global Technologies, Inc.
    Inventors: John Butwin, Michael J. Monaghan, Maria Eugenia Protopapas, Robert Cary Haase, Stephen Michael Cicala, Wolfgang Wickler