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WO1999015774A1 - Systeme de detection de fuite de vapeur a bobine electromagnetique commune pour la commande d'une pompe et d'une valve d'evacuation - Google Patents

Systeme de detection de fuite de vapeur a bobine electromagnetique commune pour la commande d'une pompe et d'une valve d'evacuation Download PDF

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Publication number
WO1999015774A1
WO1999015774A1 PCT/CA1998/000894 CA9800894W WO9915774A1 WO 1999015774 A1 WO1999015774 A1 WO 1999015774A1 CA 9800894 W CA9800894 W CA 9800894W WO 9915774 A1 WO9915774 A1 WO 9915774A1
Authority
WO
WIPO (PCT)
Prior art keywords
armature
pump
set forth
distal end
electromagnet
Prior art date
Application number
PCT/CA1998/000894
Other languages
English (en)
Inventor
John E. Cook
Paul D. Perry
Original Assignee
Siemens Canada Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/065,964 external-priority patent/US5967124A/en
Application filed by Siemens Canada Limited filed Critical Siemens Canada Limited
Publication of WO1999015774A1 publication Critical patent/WO1999015774A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
    • F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir
    • F02M25/0809—Judging failure of purge control system
    • F02M25/0818—Judging failure of purge control system having means for pressurising the evaporative emission space

Definitions

  • This invention relates generally to an on-board leak detection system for detecting fuel vapor leakage from an evaporative emission space of an automotive vehicle fuel system, and more especially to a leak detection system that contains both an electric-operated pump and an electric-operated vent valve
  • a known on-board evaporative emission control system for an automotive vehicle comprises a vapor collection canister that collects volatile fuel vapors generated in the headspace of the fuel tank by the volatilization of liquid fuel in the tank and a purge valve for periodically purging fuel vapors to an intake manifold of the engine
  • a purge valve for periodically purging fuel vapors to an intake manifold of the engine
  • a known type of purge valve sometimes called a canister purge solenoid (or
  • CPS CPS valve
  • a solenoid actuator that is under the control of a microprocessor-based engine management system, sometimes referred to by various names, such as an engine management computer or an engine electronic control unit
  • evaporative emission space that is cooperatively defined primarily by the tank headspace and the canister is purged to the engine intake manifold through the canister purge valve
  • a CPS-type valve is opened by a signal from the engine management computer in an amount that allows intake manifold vacuum to draw fuel vapors that are present in the tank headspace and/or stored in the canister for entrainment with combustible mixture passing into the engine's combustion chamber space at a rate consistent with engine operation so as to provide both acceptable vehicle d ⁇ veability and an acceptable level of exhaust emissions
  • Certain governmental regulations require that certain automotive vehicles powered by internal combustion engines which operate on volatile fuels such as gasoline have evaporative emission control systems equipped with an on-board diagnostic capability for determining if a leak is present in the evaporative emission space It has heretofore been proposed to make such a determination by temporarily creating a pressure condition in the evaporative emission space which is substantially different from the ambient atmospheric pressure, and then watching for a change in
  • a general aspect of the invention relates to an on-board evaporative emission leak detection system for detecting leakage from an evaporative emission space of a fuel system of an automotive vehicle comprising a pump for pumping gaseous fluid with respect to an evaporative emission space, a vent valve that is selectively ) operable to a first state that vents the evaporative emission space to atmosphere and to a second state that does not vent the evaporative emission space to atmosphere, and an electromechanical actuator for operating both the pump and the vent valve comprising, an electric device for receiving an electric control signal having a first component for controlling operation of the pump and a second component for controlling operation of the vent valve a first electromechanical coupling operatively coupling the device with the pump such that the pump operation is controlled by the first component of the electric control signal and a second electromechanical coupling operatively coupling the device with the vent valve such that the vent valve operation is controlled by the second component of the electric control signal
  • the invention is further characterized by a number of more specific aspects including the device being an electromagnet comprising a pair of electric terminals via which the control signal is conducted to the electromagnet to create an associated magnetic flux field, the electromagnet comprising a single solenoid coil through which electric current flow representing the control signal is conducted to create the magnetic flux field, the electromagnet comprising an E-shaped stator comprising outer legs and a middle leg, the single solenoid coil being disposed on the middle leg of the stator, the magnetic flux field comprising a first magnetic circuit that includes a first of the outer legs and a first portion of the middle leg, and the second magnetic circuit including a second of the outer legs and a second portion of the middle leg, the first electromechanical coupling comprising a first armature having a distal end that is disposed proximate a distal end of the stator middle leg and a distal end of the first outer leg of the stator, and the second electromechanical coupling comprising a second armature having a distal end that is
  • Another general aspect of the invention relates to a leak detection system comprising an electromagnet coil, an electromechanically operated pump, and an electromechanically operated valve, wherein the pump and the valve share a common portion of the electromagnet coil for their respective operation
  • More specific aspects include the pump and the valve sharing the entire electromagnet coil, and the coil comprising a winding having two terminations via which respective electric current components for operating the pump and the valve respectively can flow through the winding
  • Still another general aspect of the invention relates to a method of operating a pump and a valve during detection of leakage from an evaporative emission space of a fuel system of an automotive vehicle, the method comprising conducting through a common portion of an electromagnet coil, electric current that has a first component for operating the pump and a second component for operating the valve
  • the method may further comprise conducting the electric current through the entire electromagnet
  • Still another general aspect of the invention relates to a method of detecting leakage from an evaporative emission space of a fuel system of an automotive vehicle the method comprising operating a pump and a valve from a commonly shared portion of an electromagnet coil, and monitoring an operating parameter than conveys information representative of pressure in the evaporative emission space
  • the method may further comprise the pump and valve sharing the entire electromagnet coil, and the monitoring step comprising monitoring evaporative emission space pressure by an electric pressure sensor
  • an on-board evaporative emission leak detection system for detecting leakage from an evaporative emission space of a fuel system of an automotive vehicle, the system comprising a pump for pumping gas to create pressure in the evaporative emission space suitable for performance of a leak test, a vent valve that is selectively operable to a first state for venting the evaporative emission space to atmosphere and to a second state that does not vent the evaporative emission space to atmosphere and an electromechanical actuator comprising an electromechanical mechanism for operating one of the pump and the vent valve comprising an electric device for receiving an electric control signal, an electromechanical coupling operatively coupling the device with the one of the pump and vent valve comprising an armature having a proximal end mounting the armature for operation and a free distal end disposed to be acted upon by the electric device to operate the armature in accordance with the control signal
  • FIG. 1 is a general schematic diagram of an exemplary automotive vehicle evaporative emission control system embodying principles of the invention and comprising a leak detection module (LDM) and a fuel vapor collection canister
  • LDM leak detection module
  • FIG. 1 is a general schematic diagram of an exemplary automotive vehicle evaporative emission control system embodying principles of the invention and comprising a leak detection module (LDM) and a fuel vapor collection canister
  • LDM leak detection module
  • FIG. 1 is a general schematic diagram of an exemplary automotive vehicle evaporative emission control system embodying principles of the invention and comprising a leak detection module (LDM) and a fuel vapor collection canister
  • LDM leak detection module
  • Figure 2 is schematic diagram of the integrated assembly of Figure 1
  • Figure 3 is a top plan view showing the interior of an exemplary embodiment of LDM
  • Figure 4 is a vertical cross section view in the direction of arrows 4-4 in Figure
  • Figure 5 is a full bottom view in the direction of arrows 5-5 in Figure 4
  • Figure 6 is a full left side view in the direction of arrows 6-6 in Figure 4
  • Figure 7 is a full top view in the direction of arrows 7-7 in Figure 4
  • Figure 8 is a graph plot useful in explaining operation
  • Figure 9 is another graph plot useful in explaining operation
  • Figure 10 is a view similar to Figure 3 showing a second embodiment
  • Figure 1 1 is a view similar to Figure 4 showing the second embodiment
  • FIG 1 shows an automotive vehicle evaporative emission control (EEC) system 10 in association with an internal combustion engine 12 that powers the vehicle a fuel tank 14 that holds a supply of volatile liquid fuel for the engine, and an engine management computer (EMC) 16 that exercises certain controls over operation of engine 12
  • EEC system 10 comprises a vapor collection canister (charcoal canister) 18, a proportional purge solenoid (PPS) valve 20, a leak detection module (LDM) 22 and a particuiate filter 24
  • LDM 22 and canister 18 are portrayed as an integrated assembly, but alternatively they could be two discrete components that are operatively associated by external conduits
  • the interior of canister 18 comprises a vapor adsorptive medium 18A that separates a clean air side 18B of the canister's interior from a dirty air side 18C to prevent transpassing of fuel vapor from the latter to the former
  • An inlet port 20A of PPS valve 20 and a tank headspace port 14A that provides communicates with headspace of fuel tank 14 are placed in common fluid communication with a port 22A of LDM 22 by a fluid passage 26
  • port 22A is communicated with canister dirty air side 18C via a fluid passage 27
  • Another fluid passage 28 communicates an outlet port 20B of PPS valve 20 with an intake manifold 29 of engine 12
  • Another fluid passage 30 communicates a port 22B of LDM 22 to atmosphere via filter 24
  • Another fluid passage 32 that exists interiorly of the integrated assembly of canister 18 and LDM 22 communicates LDM 22 with canister clean air side 18B Headspace of tank 14, dirty air side 18C of canister 18, and fluid conduit 26 thereby collectively define an evaporative emission space within
  • EMC 16 receives a number of inputs, collectively designated 34, (engine- related parameters for example) relevant to control of certain operations of engine 12 and its associated systems, including EEC system 10
  • One electrical output port of EMC 16 controls PPS valve 20 via an electrical connection 36
  • other ports of EMC 16 are coupled with LDM 22 via electrical connections, depicted generally by the reference numeral 38
  • EMC 16 commands LDM 22 to an active state as part of an occasional leak detection test procedure for ascertaining the integrity of EEC system 10, particularly the evaporative emission space that contains volatile fuel vapors, against leakage
  • EMC 16 commands PPS valve 20 to close
  • LDM 22 reposes in an inactive state, and in doing so provides an open vent path from the evaporative emission space, through itself and filter 24 to atmosphere This allows the evaporative emission space to breathe, but without allowing escape of fuel vapors to atmosphere due to the presence of vapor collection medium 18A in the vent path to
  • One-way valves 56, 58 are arranged to allow pump 50 to draw atmospheric air through its inlet and to deliver pumped air through its outlet Vent valve 52 is normally open meaning that when not being electrically actuated, it allows the passage of air through itself without significant restriction, and when electrically actuated it disallows air passage through itself
  • Switch 54 assumes a first condition closed for example, so long as the pressure at measuring port 54B is less than or equal to a certain positive pressure relative to the pressure at reference port 54A When the pressure at measuring port 54B is greater than that certain positive pressure, switch 54 assumes a condition, open for example, different from the first condition
  • Figures 3-7 show further detail of an exemplary LDM 22 A walled enclosure
  • Container 102A and cover 102B are preferably injection molded plastic parts that fit together in a sealed manner along mating edges 105A 105B Pump 50 and valve 52 are disposed within space 103 while switch 54 is disposed on the exterior of cover 102B Each is suitably secured on enclosure 102
  • An electromagnet assembly 104 that serves as a common electric actuator for both pump 50 and vent valve 52 comprises a number of identical E-shaped ferromagnetic laminations stacked together to form a stator 109 As viewed in plan in Figure 3, stator 109 includes three parallel legs, namely two outer legs 122, 124 of identical width and a somewhat wider middle leg 126, projecting perpendicularly away from a side 127 Electromagnet assembly 104 further comprises an electromagnet 112 that comprises a plastic bobbin 114 containing an electromagnet coil 116 Bobbin 114 fits onto stator middle leg 126 with its axis 119 coincident with that of middle leg 126
  • Electromagnet 116 comprises a length of magnet wire wound in convolutions around the core of bobbin 114 between axial end flanges of the bobbin The respective ends of the magnet wire are joined to respective ones of a pair of electric terminals 112A that mount on an end flange of bobbin 114 Each terminal projects transversely away from bobbin 114 through cover 102B
  • Electromagnet assembly 104 is securely held on container 102A by several posts 120 that are part of the injection molded enclosure 102
  • Each post 120 comprises a shoulder 121 spaced a certain distance from the container's bottom wall and a catch 123 spaced still farther away
  • the thickness of stator 109 is such that its outer margin along legs 122, 124 and side 127 can be snugly lodged between shoulders 121 and catches 123
  • Pump 50 comprises a housing 144 that includes apertured tabs at several locations on its exterior so that it can be mounted on enclosure 102 by passing threaded fasteners 141 through those tabs and tightening them in holes in the enclosure
  • a pumping mechanism 140 is disposed at one side of housing 144
  • Housing 144 comprises a circular flange 146 and a tubular wall 148 extending from flange 146 to an
  • Pumping mechanism 140 comprises a movable wall 150 having a circular perimeter margin disposed against a ⁇ m 152 of flange 146
  • Wall 150 is shown to comprise a flexible, but fluid-impermeable, part 154 and a rigid part 156
  • Part 154 is a fuel-tolerant elastome ⁇ c material that is united with part 156 such as by known insert- molding methods thereby intimately associating the two parts 154 156 in assembly
  • the outer perimeter margin of movable wall 150 comprises a circular bead 158 in part 154
  • Rim 152 comprises a circular groove within which bead 158 is disposed Bead 158 is held in that groove by a circular clinch ring 162 which is fitted over the abutted perimeter margins of wall 150 and flange 146 and which has an outer perimeter that is deformed and crimped onto the abutted perimeter margins of wall 150 and flange 146 in the manner shown
  • This serves to seal the two perimeter margins together so that a pump
  • Pumping chamber 164 may be considered to have an axis 166 that is concentric with flange 146 and wall 150 Axis 166 is offset from an axis 168 of tubular wall 148
  • Tubular wall 148 comprises a passage 170 extending along axis 168 from pumping chamber 164 and opening to the interior space 103 of enclosure 102 at the side of housing 144 opposite pumping chamber 164
  • Housing 144 still further comprises a branch passage 172 that tees into passage 170
  • One-way valve 58 is disposed between pumping chamber 164 and passage
  • Valve 58 comprises an elastome ⁇ c umbrella valve element 178 mounted on an appropriately apertured internal wall of housing 144 that separates pumping chamber 164 from passage 170
  • Spaced from valve 58 circumferentially about axis 166 is one-way valve 56, which comprises an umbrella valve element 181
  • Valve 56 has a construction like that of valve 58, with element 181 being mounted on a wall of housing 144 to allow fluid flow in a direction from the interior space 103 of enclosure 102 into pumping chamber 164 but not in an opposite direction
  • Ports 22A, 22B are shown in Figures 3-7 as respective nipples of the injection molding forming container 102A
  • the nipple forming port 22B is open to the interior space 103 of enclosure 102 proximately adjacent electromagnet 104 to provide continuous venting of interior space 103 to atmosphere through filter 24
  • the nipple forming port 22A is open to a passage 180
  • ⁇ passage 172 is defined by a short tubular wall 186 depending from housing 144
  • An O-r ⁇ ng seal 188 is disposed around the exterior of wall 186 for securing fluid-tight sealing of wall 188 to that of a hole 190 extending through the bottom wall of container 102A to port 184
  • Measuring port 54B of pressure switch 54 is tapped into passage 180 by a tap passage 191 in enclosure 102 that is separate from interior space 103
  • a o nipple formation 195 molded integrally into container 102A tees into passage 180 to form a portion of tap passage 191
  • Another portion of tap passage 191 extends from switch 54 to a tube 193 that depends from the interior of cover 102B to telescopically engage the free end of nipple formation 195 in a fluid-tight joint when cover 102B and container 102A are assembled together
  • An armature 302 operatively couples electromagnet 104 with vent valve 52
  • Valve 52 comprises a closure 142 that is operated by electromagnet 104 to selectively seat on and unseat from a surface 143 of housing 144 that circumscribes passage 170 at the side of housing 144 opposite pumping chamber 164
  • Figure 3 shows closure 142 in unseated position, opening passage 170 to interior space 103, this is 0 the open position of valve 52 that is assumed when armature 302 is not being actuated by energization of electromagnet 104
  • FIG. 300 shows the position assumed when armature 300 is not being actuated by energization of electromagnet 104 to operate pumping mechanism 5 140
  • the illustrated embodiment shows armatures 300 302 sharing several common parts These parts include a formed metal spring strip 304 and a mount 305 for mounting the spring strip on a portion of pump housing 144
  • Spring strip 304 comprises a metal band that is formed to a U-shape comprising a base 306 and two
  • Armature 302 comprises a ferromagnetic slug 312, preferably magnetically soft iron, affixed to the distal end of side 310, and armature 300, a permanent magnet 314 affixed to the distal end of side 308.
  • Closure 142 mounts on side 310 proximal to slug 312.
  • Closure 142 comprises a rigid disk 206, stamped metal for example, onto which elastomeric material 208 has been insert molded so that the two are intimately united to form an assembly.
  • the elastomeric material forms a grommet-like post 210 that projects perpendicularly away, and to one axial side of, the center of disk 206.
  • Post 210 comprises a shape, including an axially central groove 212, providing for the attachment of closure 142 to side 310 by inserting the free end of post 210 through a hole in side 310 to seat the hole's margin in groove 212.
  • the elastomeric material is formed to provide a lip seal 214 that is generally frustoconically shaped and canted inward and away from disk 206 on the axial side of the disk opposite post 210.
  • Slug 312 is disposed proximate, but spaced from, the free ends of legs 124, 126, and magnet 314, proximate, but spaced from, the free ends of legs 122, 126.
  • the combination of slug 312, leg 124. a portion of leg 126, and the portion of side 127 joining the proximal ends of legs 124, 126 form a magnetic circuit 315 for operating valve 52.
  • the combination of magnet 314, leg 122, a portion of leg 126, and the portion of side 127 joining the proximal ends of legs 122, 126 form a magnetic circuit 313 for operating pumping mechanism 140.
  • Figure 3 discloses that in the inactive state of LDM 22, slug 312 is disposed asymmetric to the free ends of legs 124, 126, and consequently, vent valve 52 is open. This causes the evaporative emission space to be vented to atmosphere through a vent path comprising port 184, an adjoining portion of hole 190, branch passage 172, a portion of passage 170, interior space 103, port 22B, fluid passage 30, and filter 24.
  • magnet 314 is disposed asymmetric to the free ends of legs 122, 126.
  • a joint 316 operatively connects strip 304 to movable wall 150 of pumping mechanism 140. This joint comprises a dimple in side 308 that seats the tip end of a complementary shaped post projecting from part 156 along axis 166, and a clip 319 maintaining the seated relationship
  • spring strip 304 In the inactive state of LDM 22, spring strip 304 assumes a relaxed condition in which sides 308, 310 are unflexed In the LDM's active state however, electromagnet assembly 104 is effective to resiliently flex side 310 to close vent valve 52, and to resiliently oscillate side 308 to operate pumping mechanism 140
  • Spring strip 304 has a thickness oriented in the plane of Figure 3 and a width oriented in the plane of Figure 4
  • Mounting 305 comprises an elastomeric grip 307 engaging base 306
  • Grip 307 is in covering relation to at least opposite faces of the width of strip 304, and as viewed in Figure 3, has a generally uniform thickness
  • An end of housing 144 opposite wall 148 comprises a curved trough 309 whose curvature matches that of grip 307 and whose width is related to that of grip 307 to allow the latter to be securely held therein, as shown
  • Opposite ends of trough 309 confine grip 307, but comprise slits that allow strip 304 to pass through Mount 305 therefore serves to cantilever-mount each side 308, 310 of spring strip 304 From the relaxed position shown by Figure 3, side 308 can flex in the direction indicated by the arrow 320, and side 310, in the direction indicated by the arrow 322 Flexing of side 308 is caused by the energization of magnetic circuit
  • Slug 312 is preferably a magnetically soft material
  • Energization of coil 116 which causes the distal end of leg 124 to become a magnetic pole of one polarity and the portion of the distal end of leg 126 proximate the distal end of leg 124 to become a magnetic pole of opposite polarity, will create a force on slug 312 in the general direction of arrow 322
  • a sufficiently large force will flex side 310 in the manner described, causing an amplified force to operate valve 52 from open to closed because the cantilever mounting of side 310 acts similar to a second class lever
  • Closure 142 is thereby forced to seal the open end of passage 170 closed due to the action of lip seal 214 with the surface of housing 144 around the open end of passage 170 Consequently, the evaporative emission space ceases to be vented to atmosphere because the vent path through vent valve 52 has now been closed
  • a circuit board assembly 350 is disposed on the exterior of cover 102B adjacent switch 54, and the two are laterally bounded by a raised perimeter wall 354 that is a part of the cover Terminals of switch 54 connect with certain circuits on circuit board assembly 350, as do terminals 112A of electromagnet 112 A surround 356 protrudes from the outside of wall 354 at one side of enclosure 102 External end portions of electric terminals that may provide for connection of switch 54 and coil 116 directly with EMC 16 protrude from circuit board assembly 350 where they are bounded by surround 356 to form an electric connector 357 A complementary connector (not shown) that forms one termination of the connection represented by the reference numeral 38 in Figure 1 mates with connector 357 When a leak detection test is to be performed, EMC 16 operates LDM 22 to the active state and operates PPS valve 20 closed Circuit board assembly 350 may however contain electric circuits associated with coil 116 and switch 54 for performing tests and diagnostic procedures independent of commands from EMC 16, storing test data, and conveying stored test data to EMC 16 Both circuit board assembly 350
  • electromagnet assembly 104 is energized by an electric driver circuit (not shown) that delivers to coil 116 an electric signal input that may be considered to comprise two components namely, a first signal component that closes vent valve 52 by energizing magnetic circuit 315 such that a force is exerted on slug 312, which force, in conjunction with the force vs deflection characteristic of side 310, the inertial mass of armature 302 disposed about mount 305, and any pressure differential acting on closure 142, is effective to seal closure 142 closed against the open end of passage 170 and to maintain that relationship while LDM 22 continues to be in its active state during the test, and a second signal component that energizes magnetic circuit 313 such that a force is exerted on magnet 314, which force is effective to oscillate side 308, and thereby stroke pumping mechanism 140, while the evaporative emission space under test ceases to be vented to atmosphere through LDM 22 due to valve 52 having been closed Electromagnet assembly 104 therefore comprises a single sole
  • a test comprises monitoring an operating parameter representative of evaporative emission space pressure
  • One method of monitoring comprises utilizing pressure switch 54 to sense pressure Reference port 54A is communicated to interior space 103 by a nipple that extends through the wall of cover 102B in a sealed manner
  • Switch 54 comprises a set of contacts that are normally in a first state closed for example The switch contacts will remain in that state until the evaporative emission space pressure as sensed by measuring port 54B, exceeds the switch setting, approximately 4 inches of water as one example whereupon the contacts will switch to a second state, open for example If leakage from the evaporative emission space is present, the pressure will then begin to decay The switch contacts will revert to their first state after a certain amount of the test pressure has been lost
  • Graph plot 400 depicts the second component of an electric signal input to coil 116 as a function of time
  • Graph plot 402 depicts the corresponding pressure differential sensed by switch 54
  • the second component of the electric signal input comprises a continuously repeating pulse that continuously operates pump mechanism 140 to progressively increases the pressure in the evaporative emission space under test
  • the switch contacts change state, interrupting the second component of the electric signal input and stopping pump mechanism 140 Leakage will be evidenced by ensuing pressure decay
  • EMC 16 pulses coil 116 with a fixed number of pulses, once again operating pumping mechanism 140 This will increase the evaporative emission space test pressure sufficiently to exceed the pressure setting of switch 54
  • An exemplary LDM 22 may operate pump mechanism 140 with 50 hertz, 50% duty cycle pulses
  • the volume of pumping chamber 164 relative to the hysteresis of switch 54 may allow for a pulse group G to comprise a relatively small number of pulses say one to five pulses for example
  • pump mechanism 140 is a positive displacement mechanism that is charged to a given volume of atmospheric pressure air at the beginning of each stroke a full pump downstroke delivers a known quantity of air Because the described process for obtaining a leak size measurement is based on flowing known amounts of air, it is unnecessary for the measurement to be corrected for either volume of the evaporative emission space under test or any particular pressure therein
  • LDM 22' of Figures 10 and 11 is like LDM 22 of Figures 3-7, and the same reference numerals are used in all such Figures to designate similar parts LDM 22' possesses some differences however
  • the axis of post 210 is made non- perpendicular to the length of side 310 such that when closure 142 is closing the open end of passage 170, the post's axis is substantially perpendicular to surface 143 of housing 144 against which lip 214 seals Rather than employing a single grip 307
  • LDM 22' comprises three discrete grips 307' disposed in discrete slots that are spaced apart along the curvature of the mounting trough 309
  • enclosure 102 comprises apertured tabs 404 on its exterior for fastening to canister 18, and the opposite side walls of the enclosure comprise small alcoves 406 to allow
  • LDM 22 relates to the sharing of a common portion of electromagnet 112 by both armatures 300, 302, the illustrated embodiment sharing the entire electromagnet coil winding
  • the invention offers potential for economies in LDM fabrication cost and packaging size
  • the electric signal input for operating both armatures comprising a first electric current for operating the pump and a second for operating the vent valve, is conducted through the entire coil winding via only two electric terminals, namely terminals 112A

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Supplying Secondary Fuel Or The Like To Fuel, Air Or Fuel-Air Mixtures (AREA)

Abstract

L'invention porte sur un système incorporé de détection de fuite d'émissions de vapeur, ce système comportant un module détectant les fuites à partir d'un espace d'émission de vapeur d'un véhicule automobile. L'espace interne du module communique avec l'atmosphère. Une pompe est placée dans cet espace et comporte un orifice d'admission en relation avec l'espace interne et une voie d'écoulement au niveau de son orifice d'évacuation de sorte que la pompe crée une pression dans l'espace d'émission de vapeur approprié pour effectuer un test de fuite. Une valve d'évacuation est également placée dans l'espace et est actionnée sélectivement pour purger la voie d'écoulement communiquant avec l'espace. Un actionneur électromagnétique comporte une bobine électromagnétique unique qui actionne à la fois la pompe et la valve d'évacuation au moyen d'induits montés en porte-à-faux réagissant au courant de commande électrique circulant dans la bobine, une première composante du courant permettant de commander la pompe et une seconde composante de commander la valve d'évacuation.
PCT/CA1998/000894 1997-09-22 1998-09-22 Systeme de detection de fuite de vapeur a bobine electromagnetique commune pour la commande d'une pompe et d'une valve d'evacuation WO1999015774A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US5971697P 1997-09-22 1997-09-22
US60/059,716 1997-09-22
US6379997P 1997-10-31 1997-10-31
US60/063,799 1997-10-31
US09/065,964 US5967124A (en) 1997-10-31 1998-04-24 Vapor leak detection system having a shared electromagnet coil for operating both pump and vent valve
US09/065,964 1998-04-24

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WO1999015774A1 true WO1999015774A1 (fr) 1999-04-01

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5146902A (en) 1991-12-02 1992-09-15 Siemens Automotive Limited Positive pressure canister purge system integrity confirmation
WO1994018447A1 (fr) * 1993-02-03 1994-08-18 Siemens Electric Limited Confirmation d'integrite du systeme de purge de collecteur a pression positive
US5383437A (en) 1992-12-23 1995-01-24 Siemens Automotive Limited Integrity confirmation of evaporative emission control system against leakage
US5474050A (en) 1995-01-13 1995-12-12 Siemens Electric Limited Leak detection pump with integral vent seal
DE19644610A1 (de) * 1996-10-26 1998-04-30 Bosch Gmbh Robert Tankentlüftungseinrichtung für Kraftfahrzeuge

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5146902A (en) 1991-12-02 1992-09-15 Siemens Automotive Limited Positive pressure canister purge system integrity confirmation
US5383437A (en) 1992-12-23 1995-01-24 Siemens Automotive Limited Integrity confirmation of evaporative emission control system against leakage
WO1994018447A1 (fr) * 1993-02-03 1994-08-18 Siemens Electric Limited Confirmation d'integrite du systeme de purge de collecteur a pression positive
US5474050A (en) 1995-01-13 1995-12-12 Siemens Electric Limited Leak detection pump with integral vent seal
DE19644610A1 (de) * 1996-10-26 1998-04-30 Bosch Gmbh Robert Tankentlüftungseinrichtung für Kraftfahrzeuge

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