FIELD OF INVENTION
[0001] The present invention relates to a purge valve, and more particularly the
present invention relates to the solenoid purge valve for evaporative emission
control in vehicles.
BACKGROUND OF THE INVENTION
[0002] An emission of air pollutants such as hydrocarbons, carbon monoxide,
nitrogen oxide, sulphur oxide etc. in atmosphere have shown severe effects on
10 health of living organism and environment. Escape of fuel vapours from the fuel
tank of a vehicle is a major source of evaporative emission. In past few decades the
evaporative emission standards have been introduced throughout the globe. The
emission standards define the acceptable limit of release of air pollutants into
atmosphere. To follow the emission standards set by the governments of respective
15 countries the use of evaporative emission control device has become mandatory.
[0003] Such kind of device used to control the evaporative emission from a
vehicle is a solenoid purge valve. In evaporative emission control system fuel
vapours inside the fuel tanks are allowed to be accumulated in the closed chamber
called as canister. The solenoid purge valve is a device that allows fuel vapours that
20 are stored in canister to transmit into engine through throttle body or carburettor. A
solenoid purge valve is a one-way valve having normally closed condition. An
electromechanical type solenoid purge valve operates on specific frequency range
along with Duty ratio. It consists of an electromechanical arrangement for the
actuation with ON-OFF mode or PWM operated proportional discharge mode. The
25 electrical input is received from the ECU.
[0004] Referring to Fig. I, the conventional solenoid purge valve (I 00) is
shown. Conventionally the solenoid purge valve includes a housing (I 1 0), a
connector (I lOa), a cover (120) having an inlet port (120a) and an outlet port
(120b), a coil assembly (130), a fixed core (140), a yoke assembly (150), a movable
30 core (160), a sealing rubber (170), a spring (180) etc. When said solenoid purge
2
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valve (1 00) gets energized, the electromagnetic field get generated inside the
housing (11 0). Due to effect of said magnetic field the movable core (160) gets
attracted towards the fixed core (140). As the movable core (160) gets attracted
towards the fixed core (140), it opens the outlet (120b ), that enables fuel vapours
5 from canister to travel to engine due to vacuum creation in suction stroke.
[0005] Conventionally the movable core (160) is coaxially aligned with the
inlet port (120a).The movable core (160) remains abutted against the inlet port
(120a) during the normally closed condition of the solenoid purge valve (100) and
restricts the entry of fuel vapours inside the valve. The sealing means (170) is used
10 to enhance sealing effect. When the solenoid purge valve gets energised the
movable core (160) gets attracted towards the fixed core ( 140) so as to open the
solenoid purge valve (I 00). As a result vapours accumulated in the canister enters
the valve (100) through inlet port (120a) and travels towards the outlet port (120b)
due to vacuum generated during suction stroke of engine.
15 [0006] During its movement towards fixed core magnetic force experienced by
M.C. (Moving Core) is not constant, magnetic force is minimum at valve closed
condition due to maximum air gap between M.C. (Moving Core) & F.C. (Fix Core)
and magnetic force is maximum at valve open condition due to minimum air gap
between M.C. & F.C. This phenomena results in non-conformance of valve
20 parameters such as minimum operating voltage, release voltage and valve operating
at variable frequencies to overcome this issue we need to increase air gap between
M.C. & F.C. which in turn requires more copper wire to overcome the increased air
gap. Thus more copper wire increase the cost.
[0007] To overcome aforementioned drawbacks present in the conventional
25 solenoid purge valve, there is a need of the solenoid purge valve having constant
magnetic force.
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OBJECTS OF THE INVENTION
[0008] The main object of a present invention is to provide a solenoid purge
valve having constant magnetic force.
[0009] The another object of the present invention is to provide the solenoid
5 purge valve that improves overall efficiency.
[00010] The another object of the present invention is to provide the solenoid
purge valve that is cost effective.
[00011] The another ol:>ject of the present invention is to provide the solenoid
purge valve with compact design.
10 SUMMARY OF THE INVENTION
[00012] The present invention relates to a purge valve, and more particularly the
present invention relates to the solenoid purge valve for evaporative emission
control in vehicles.
[00013] Tn embodiment of present invention a solenoid purge valve (200)
15 including a housing (21 0), a cover (220) having at least an inlet port (220a), a
central port (220b) and outlet port (220c), a coil assembly (230) configured to be
magnetized when power is supplied from a power source; a fixed core (240)
configured to generate a magnetic field when the coil (230) is magnetized, a
movable core (250) configured to get attracted towards the fixed core (240) when
20 the coil (230) is magnetized and configured for opening and closing an inlet port
(220a), a spring (260) configured to tightly move the movable core (250) towards
the cover (220), a sealing means (270) configured to act as seal between the central
port (220b) and outlet port (220c), a yoke assembly (280) and a 0-ring (290).
[00014] Tn another embodiment of present invention the fixed core (240) having
25 blind hole at top surface of the fixed core (240).
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[00015] In another embodiment of present invention the solenoid purge valve
(200) configured to provide constant magnetic force.
[00016] In another embodiment of present invention lower part of movable core
(250) fit inside the blind hole (h) affixed core (240).
5 [00017] In another embodiment of present invention the blind hole (h) of fixed
core (240) configured to provide constant air gap.
[00018] In another embodiment of present invention the ratio affixed core (240)
and number of Ampere turns is less than or equal to 0.0015 mm/Ampere turn.
[00019] In another embodiment of present invention inner diameter of fixed
10 core (240) is greater than outer diameter of movable core (250) by at least 0.1 mm
to 0.25mm.
[00020] In another embodiment of present invention ratio of fixed core (240)
counter to movable core (250) step 1.2 to 1.3.
[00021] In another embodiment of present invention said arrangement
15 configured for applying constant magnetic force.
BRIEF DESCRIPTION OF THE DRAWINGS
[00022] The accompanying drawings constitute a part of the description and are
used to provide further understanding of the present invention. Such accompanying
drawings illustrate the embodiments of the present invention which are used to
20 describe the principles of the present invention together with the description.
[00023] Fig. 1 shows a cross sectional view of a conventional solenoid purge
valve disclosed in the prior art;
[00024] Fig. 2 shows an exploded view of a solenoid purge valve in accordance
with the preferred embodiment of a present invention.
5
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10
[00025] Fig. 3 shows a cross sectional view of a solenoid purge valve 111
accordance with the preferred embodiment of a present invention.
[00026] Fig. 4a shows comparison of copper mass(%) between prior art design
and present design.
[00027] Fig. 4b shows comparison of operating frequency vs voltage between
prior art design and present design.
[00028] Fig. 4c shows comparison of force vs air gap voltage between prior art
design and present design.
[00029] Fig. 5a shows a cross sectional view of fixed core.
[00030] Fig. 5b shows an enlarged view oftop surface of fixed core.
DETAILED DESCRIPTION OF THE INVENTION
[00031] As used in the description herein and throughout the claims that follow,
the meaning of "a," "an," and "the" includes plural reference unless the context
clearly dictates otherwise. Also, as used in the description herein, the meaning of
15 "in" includes "in" and "on" unless the context clearly dictates otherwise.
[00032] If the specification states a component or feature "may", "can", "could",
or "might" be included or have a characteristic, that particular component or feature
is not required to be included or have the characteristic.
[00033] Exemplary embodiments will now be described more fully hereinafter
20 with reference to the accompanying drawings, in which exemplary embodiments
are shown. This disclosure may however, be embodied in many different forms and
should not be construed as limited to the embodiments set forth herein.
[00034] Fig. 2 and Fig. 3 show a exploded view and a cross sectional view of a
solenoid purge valve (200) in accordance with the preferred embodiment of a
25 present invention is shown. The solenoid purge valve (200) includes a housing
6
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(21 0) and a cover (220). The housing (21 0) includes a coil assembly (230), a fixed
core (240), a movable core (250), a spring (260), a sealing means (270), a yoke
assembly (280) and a 0-ring (290). The cover (220) is having an inlet port (220a),
a central port (220b) and outlet port (220c ).
5 [00035] Again referring Fig. 3, the movable core (250) and the spring (260) are
coaxially aligned with the central port (220b ). The movable core (250) is abutted
against the central port (220b) during the normally closed condition so as to restrict
entry of fuel vapours inside the valve. When the solenoid purge valve (200) gets
energised the movable core (250) gets attracted towards the fixed core (240) so as
10 to open the solenoid purge valve (200) by saturating some part of fixed core (240).
This is achieved by adding blind hole to top surface of fixed core. Such that lower
part of movable core (250) fit inside the blind hole (h) of fixed core (240).
[00036] In embodiment of present invention a solenoid purge valve (200)
including a housing (21 0), a cover (220) having at least an inlet port (220a), a
15 central port (220b) and outlet port (220c ), a coil assembly (230) configured to be
magnetized when power is supplied from a power source; a fixed core (240)
configured to generate a magnetic field when the coil (230) is magnetized, a
movable core (250) configured to get attracted towards the fixed core (240) when
the coil (230) is magnetized and configured for opening and closing an inlet port
20 (220a), a spring (260) configured to tightly move the movable core (250) towards
the cover (220), a sealing means (270) configured to act as seal between the central
port (220b) and outlet port (220c ), a yoke assembly (280) and a 0-ring (290).
[00037] In another embodiment of present invention the fixed core (240) having
blind hole at top surface of the fixed core (240).
25 [00038] In another embodiment of present invention the solenoid purge valve
(200) configured to provide constant magnetic force.
[00039] In another embodiment of present invention lower part of movable core
(250) fit inside the blind hole (h) affixed core (240).
7
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..1.... i ·-o -~ ·;· .... _ ~ ·;· ·;· 'L;"' ;..--·; .2.. ..1.... _::· .1.-. "'·-=' - -· ,'
[00040] In another embodiment of present invention the blind hole (h) of fixed
wn: (240) configurt:J to prov iut: constant air gap.
[00041] In another embodiment of present invention the ratio of fixed core (240)
and number of Ampere turns is less than or equal to 0.0015 mm/Ampere turn.
5 [00042] In another embodiment of present invention inner diameter of fixed
core (240) is greater than outer diameter of movable core (250) by at least 0.1 mm
to 0.25mm.
[00043] In another embodiment of present invention ratio of fixed core (240)
counter to movable core (250) step 1.2 to 1.3.
10 [00044] In another embodiment of present invention said arrangement
configured for applying constant magnetic force.
[00045] The non-limiting operating characteristics explained here, as movable
core (250) and fixed core (240) comes closer to each other, then the flux density in
the some portion of movable core (250) and fixed core (240) gets high & saturated,
15 and after saturation that portion's reluctance becomes equivalent to air reluctance.
Hence movable core (250) and fixed core (240) are at maximum distance (high air
gap), no portion of movable cure (250) anJ fixt:J cure (240) saturated, therefore
magnetic force is maximum, & similarly for low air gap the maximum portion of
movable core (250) and fixed core (240) get saturated hence magnetic force is
20 minimum.
[00046] During operation due to blind hole (h) of fixed core (240), the air gap
of movable core (250) and fixed core (240) maintained which is responsible for
applying constant magnetic force.
[00047] The said arrangement is configured for applying constant magnetic
25 force.
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[00048]
results;
[00049]
The invention may having following parameters for achieving best
1. The ratio of fixed core and number of Ampere turns should be less
than 0.0015 mm/Ampere turn.
2. Inner Diameter of Fixed Core> Outer Diameter ofMoving Core by
at least O.lmm~0.25mm max.
3. Ratio of Fixed Core counter to Moving Core step 1.2~ 1.3.
Referring Fig 4a, provides the reduced copper mass percentage (25%
saved over prior art).
10 [00050] Referring Fig 4b provides improved operating frequency and voltage
over prior art.
[00051] Referring Fig 4c provides sample results giving constant magnetic force
over operating air gap (changing air gap).
[00052] Referring Fig Sa provides fixed core (240) according to embodiment of
15 present invention. The fixed core (240) (h) at top surface.
[00053] Referring Fig 5b provides enlarged view of top surface.
[00054] In the above detailed description, reference is made to the
accompanying drawings that form a part thereof, however, such description should
not be considered as any limitation of scope of the present invention. The structure
20 thus conceived in the present description is susceptible of numerous modifications
and variations, all the details may furthermore be replaced with elements having
technical equivalence.
[00055] ADVANTAGES
I. Achieved constant magnetic force in valve.
25 2. Noise reduced due to addition of rubber to lower surface of the moving core.
9
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3. Minimum operating voltage, release voltage and valve operating at variable
frequencies parameters are achieved.
4. Overall performance ofvalve is improved.
5 [00056] List of reference numerals:
1. A solenoid purge valve (200)
2. A housing (21 0)
3. A cover (220)
4. An inlet port (220a)
10 5. A central port (220b)
6. An outlet port (220c)
7. A coil assembly (230)
8. A fixed core (240)
9. A movable core (250)
15 1 0. A spring (260)
11. A sealing means (270)
12. A yoke assembly (280)
13. 0-ring (290)
14. Blind hole (h)
20
10
CLAIMS
We Claim,
1. A solenoid purge valve (200) comprising:
a housing (21 0);
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a cover (220) having at least an inlet port (220a), a central port (220b) and
outlet port (220c);
a coil assembly (230) configured to be magnetized when power is supplied
from a power source;
a fixed core (240) configured to generate a magnetic field when the coil
(230) is magnetized;
a movable core (250) configured to get attracted towards the fixed core
(240) when the coil (230) is magnetized and configured for opening and
closing an inlet port (220a);
a spring (260) configured to tightly move the movable core (250) towards
the cover (220);
a sealing means (270) configured to act as seal between the central port
(220b) and outlet port (220c );
a yoke assembly (280) and
a 0-ring (290);
wherein the fixed core (240) having blind hole at top surface of the fixed
core (240);
20 wherein the solenoid purge valve (200) configured to provide constant
magnetic force.
2. The solenoid purge valve (200) as claimed in claim I, wherein lower part of
movable core (250) fit inside the blind hole (h) of fixed core (240).
25 3. The solenoid purge valve (200) as claimed in claim I, wherein the blind hole (h)
of fixed core (240) configured to provide constant air gap.
11
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2. . ··-· ·;· ;· -... _~· ' ' '·-· .2.
4. The solenoid purge valve (200) as claimed in claim I, wherein the ratio of fixed
core (240) and number of Ampere turns is less than or equal to 0.0015 mm/ Ampere
turn.
5. The solenoid purge valve (200) as claimed in claim 1, wherein inner diameter of
s fixed core (240) is greater than outer diameter of movable core (250) by at least
0.1 mm to 0.25mm.
6. The solenoid purge valve (200) as claimed in claim I, wherein ratio of fixed core
(240) counter to movable core (250) step 1.2 to 1.3.