U.S. patent application number 11/257079 was filed with the patent office on 2006-05-18 for canister.
This patent application is currently assigned to AISAN KOGYO KABUSHIKI KAISHA. Invention is credited to Masamitsu Hayakawa, Yojiro Iriyama, Yukihiko Kaneda, Takashi Nagai, Tokio Yamauchi.
Application Number | 20060102156 11/257079 |
Document ID | / |
Family ID | 36384870 |
Filed Date | 2006-05-18 |
United States Patent
Application |
20060102156 |
Kind Code |
A1 |
Yamauchi; Tokio ; et
al. |
May 18, 2006 |
CANISTER
Abstract
A canister comprises a tank port communicated with an upper air
chamber in a closed fuel tank, a purge port communicated with an
intake passage of an engine, an atmospheric port opened to the
atmosphere, and a main adsorbent chamber containing activated
carbon, and the canister is further provided with a partition plate
between the tank port and the purge port for preventing both ports
from being directly communicated with each other, so as to form a
first chamber between the main adsorbent chamber and the tank port,
and a second chamber between the main adsorbent chamber and the
purge port, and a purge buffer plate is further provided in the
main adsorbent chamber between the tank port and the purge port,
for communicating between the first and second chambers with each
other, the first chamber serves as an air chamber containing no
activated carbon while the second chamber contains activated
carbon. With this configuration, the canister has no external pipe
line, the time change in fuel concentration of purged gas during
treatment of evaporated fuel from the fuel tank is moderated in
order to restrain an engine air-fuel ratio from being abruptly
changed, and the operation ability of the engine can be
satisfied.
Inventors: |
Yamauchi; Tokio; (Obu,
JP) ; Nagai; Takashi; (Obu, JP) ; Hayakawa;
Masamitsu; (Obu, JP) ; Kaneda; Yukihiko; (Obu,
JP) ; Iriyama; Yojiro; (Toyota, JP) |
Correspondence
Address: |
STEVENS DAVIS MILLER & MOSHER, LLP
1615 L STREET, NW
SUITE 850
WASHINGTON
DC
20036
US
|
Assignee: |
AISAN KOGYO KABUSHIKI
KAISHA
Aichi-ken
JP
TOYOTA JIDOSHA KABUSHIKI KAISHA
Aichi
JP
|
Family ID: |
36384870 |
Appl. No.: |
11/257079 |
Filed: |
October 25, 2005 |
Current U.S.
Class: |
123/519 ;
96/121 |
Current CPC
Class: |
F02M 2025/0881 20130101;
F02M 2025/0863 20130101; B01D 2259/4566 20130101; B01D 53/0454
20130101; F02M 25/089 20130101; B01D 53/0415 20130101; B01D
2253/102 20130101; B01D 2259/40086 20130101; B01D 2259/4516
20130101; B01D 2258/012 20130101; F02M 25/0854 20130101; B01D
53/0446 20130101; B01D 2257/702 20130101 |
Class at
Publication: |
123/519 ;
096/121 |
International
Class: |
F02M 33/04 20060101
F02M033/04; B01D 53/02 20060101 B01D053/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 15, 2004 |
JP |
2004-330610 |
Claims
1. A canister comprising a tank port communicated with an upper air
chamber in a fuel tank, a purge port communicated with an intake
passage of an engine, an atmospheric port opened to atmosphere, and
a main adsorbent chamber containing activated carbon for adsorbing
evaporated fuel flowing from said tank port to said atmospheric
port, wherein a partition plate is provided between said tank port
and said purge port for preventing both ports from being directly
communicated with each other, a first chamber is provided between
said main adsorbent chamber and said tank port, a second chamber is
provided between said main adsorbent chamber and said purge port,
and a purge buffer plate is provided in said main adsorbent chamber
on a side of said tank port/purge port, for communicating said
first and second chambers with each other, and wherein said first
chamber serves as an air chamber containing no activated carbon and
said second chamber contains activated carbon.
2. A canister as set forth in claim 1, wherein an air-flow
resistance between said first chamber and said main adsorbent
chamber is set to be higher than that of said purge buffer plate
between said fist and second chambers.
3. A canister as set forth in claim 1, wherein pulverized coal is
used as the activated carbon contained in said second chamber, and
granulated coal is used as the activated carbon contained in other
adsorbent chambers.
4. A canister as set forth in claim 1, wherein an air-flow
resistance of a filter provided in said main adsorbent chamber on a
side of said tank port/purge ports is set per unit area to be
higher than that of a filter provided in the second chamber on a
side of said purge port and of a filter provided in said second
chamber on a side of said main adsorbent chamber.
5. A canister as set forth in claim 1, wherein an adsorbent
retaining plate is superposed on one side of a filter provided in
said main adsorbent chamber on a side of the tank port/purge ports,
and said adsorbent retaining plate is provided with at least one
constriction hole, and a total air-flow resistance of said filter
and said adsorbent retaining plate superposed with each other is
set per unit area to be higher than that of a filter provided in
said second chamber on a side of said purge port and of a filter
provided in said second chamber on a side of said main adsorbent
chamber.
6. A canister as set forth in claim 1, wherein said activated
carbon contained in said second chamber is packed by a filter
member wrapping it, but said activated carbon in other adsorbent
chambers is not packed.
7. A canister as set forth in claim 1, wherein said second chamber
containing the activated carbon has a capacity which is in a range
of 1/1,400 to 10/1,400 with respect to a capacity of the fuel
tank.
8. A canister as set forth in claim 1, wherein a vapor passage
formed in said purge buffer plate is located on an upper side in
said buffer plate in such a posture that said canister is installed
in a vehicle.
9. A canister as set forth in claim 2, wherein pulverized coal is
used as the activated carbon contained in said second chamber, and
granulated coal is used as the activated carbon contained in other
adsorbent chambers.
10. A canister as set forth in claim 9, wherein an air-flow
resistance of a filter provided in said main adsorbent chamber on a
side of said tank port/purge ports is set per unit area to be
higher than that of a filter provided in the second chamber on a
side of said purge port and of a filter provided in said second
chamber on a side of said main adsorbent chamber.
11. A canister as set forth in claim 10, wherein an adsorbent
retaining plate is superposed on one side of a filter provided in
said main adsorbent chamber on a side of the tank port/purge ports,
and said adsorbent retaining plate is provided with at least one
constriction hole, and a total air-flow resistance of said filter
and said adsorbent retaining plate superposed with each other is
set per unit area to be higher than that of a filter provided in
said second chamber on a side of said purge port and of a filter
provided in said second chamber on a side of said main adsorbent
chamber.
12. A canister as set forth in claim 11, wherein said activated
carbon contained in said second chamber is packed by a filter
member wrapping it, but said activated carbon in other adsorbent
chambers is not packed.
13. A canister as set forth in claim 12, wherein said second
chamber containing the activated carbon has a capacity which is in
a range of 1/1,400 to 10/1,400 with respect to a capacity of the
fuel tank.
14. A canister as set forth in claim 13, wherein a vapor passage
formed in said purge buffer plate is located on an upper side in
said buffer plate in such a posture that said canister is installed
in a vehicle.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a canister used in an
evaporated fuel treating equipment for an internal combustion
engine.
RELATED ART
[0002] There has been well-known such an evaporated fuel treating
equipment for an internal combustion engine, comprising a first
canister and a second canister for adsorbing evaporated fuel
generated from a fuel tank, the canisters being connected in series
with each other between an atmospheric port of the first canister
and an intake passage of an internal combustion chamber so as to
cause air flowing from the atmospheric port to flow through the
first canister and the second canister, successively, in order to
purge evaporated fuel adsorbed in these canisters, the evaporated
fuel and the air being then fed into the intake passage, a first
evaporated fuel passage for guiding evaporated fuel generated from
the fuel tank during fueling the fuel tank, and a second evaporated
fuel passage for guiding evaporated fuel generated from the fuel
tank during operation of the engine, directly into an evaporated
fuel adsorbent within the second canister so that an adsorbing
condition of the evaporated fuel adsorbent in the second canister
in the vicinity of a passage through which the evaporated fuel and
the air are fed from the second canister into the intake passage is
substantially constant from a last purge completion time to a next
purge start time (Refer to FIGS. 1 to 3 in JP-A-8-218922).
[0003] Further, there has been also well-known an evaporated fuel
processing treating equipment incorporated therein with an
adsorbent cartridge composed of a plurality of segments of
evaporated fuel adsorbent which are wrapped with a filter member
(Refer to page 2 and FIG. 1 in JP-A-2002-147297).
[0004] The evaporated fuel treating equipment disclosed in
JP-A-8-218922 has a complicated configuration and many parts since
it requires not only two canisters, that is, the first canister and
the second canister, but also a separate pipe line as the second
evaporated fuel passage, and accordingly, it is expensive in costs
and as well causes a difficulty in installation thereof in a
vehicle. Further, there has been a problem caused a risk of leakage
of evaporated fuel to the atmosphere due to break-away of a pipe
line.
[0005] The evaporated fuel treating equipment disclosed in the
JP-A-2002-147297 incorporates a plural kinds of activated carbon
which can hardly be distinguished from one another, and has caused
a problem of erroneous intermingling of activated carbon.
BRIEF SUMMARY OF THE INVENTION
[0006] Thus, an object of the present invention is to provide a
canister in an evaporated fuel treating equipment for an internal
combustion engine, which can solve the above-mentioned problems
inherent to the prior art.
[0007] The essential feature of the present invention is the
provision of a buffering activated carbon chamber which is located
adjacent to a purge port of a canister in order to add a flow of
purged gas from a space chamber adjacent to a tank port into an
intake passage of an engine by way of the buffering activated
carbon chamber during operation of the engine.
[0008] According to a first aspect of the present invention, there
is provided a canister comprising a tank port communicated with an
upper gas chamber of a fuel tank, a purge port communicated with an
intake passage of an engine, an atmospheric port opened to the
atmosphere and a main adsorbent chamber containing activated carbon
for adsorbing evaporated fuel flowing from the tank port to the
atmospheric port, wherein a partition plate is provided between the
tank port and the purge port, for preventing both ports from being
directly communicated with each other, so as to form a first
chamber between the main adsorbent chamber and the tank port and a
second chamber between the main adsorbent chamber and the purge
port, and a purge buffer plate is provided in the main adsorbent
chamber on the tank port/purge port side for communicating between
the first and second chambers, the first chamber serving an air
chamber without containing activated carbon, and the second chamber
containing activated carbon.
[0009] According to a second aspect of the present invention, it is
characterized in the canister of the first aspect that an air-flow
resistance between the first chamber and the main adsorbent chamber
is set to be higher than that of the purge buffer plate between the
first and second chambers.
[0010] According to third and ninth aspects of the present
invention, it is characterized in the canister of the first and
second aspects that pulverized coal may be used as the activated
carbon contained in the second chamber, and granulated coal be used
as the activated carbon contained in the other adsorbent
chambers.
[0011] Further, according to fourth and tenth aspects of the
invention, it is characterized in the canister of the first and
ninth aspects that the air-flow resistance of a filter provided in
the main adsorbent chamber on the tank port/purge port side is set
per unit area to be higher than that of a filter provided in the
second chamber on the purge port side and of a filter provided in
the second chamber on the main adsorbent chamber side.
[0012] Further, according to fifth and eleventh aspects of the
invention, it is characterized in the canister of the first and
tenth aspects that a adsorbent retaining plate is superposed on one
side of the filter provided in the main adsorbent chamber on the
tank port/purge port side, at least one constriction hole being
formed in the adsorbent retaining plate, and further, the total
air-flow resistance of the filter and the adsorbent retaining plate
superposed with each other is set per unit area to be higher than
that of the filter provided in the second chamber on the purge port
side and of the filter provided in the second chamber on the main
adsorbent chamber side.
[0013] Further, according to sixth and twelfth aspects of the
invention, it is characterized in the canister of the first and
eleventh aspects that the activated carbon contained in the second
chamber is packed by a filter member wrapping it, but the activated
carbon contained in the other adsorbent chamber is not packed.
[0014] Further, according to seventh and thirteenth aspects of the
invention, it is characterized in the canister of the first and
twelfth aspects that the volume of the second chamber containing
activated carbon is set to a value in a range of 1/1,400 to
10/1,400 with respect to that of the capacity of the fuel tank.
[0015] Further, according to eighth and fourteenth aspects of the
invention, it is characterized in the canister of the first and
thirteenth aspects that the position of a vapor passage in the
purge buffer plate is set to be on the upper side in the purge
buffer plate in such a posture that the canister is installed in a
vehicle.
[0016] In the first aspect of the present invention, since the
necessity of a pipe line constituting the second evaporated fuel
passage as disclosed in JP-A-8-218922 is not required, and further,
since the second chamber and the main adsorbent chamber are
communicated with each other within the casing of the canister, the
configuration of the canister becomes simple. Evaporated gas
(vapor) from a closed fuel tank of which fuel concentration greatly
varies is turned into purged gas fed into the engine and gently
varying its fuel concentration in time by adsorption and purge
functions of the activated carbon contained in the second chamber.
Thus, abrupt variation in engine air-fuel ratio is restrained,
thereby it is possible to carry out satisfactory operation of the
engine. Further, since the evaporated fuel gas can hardly flow
through the main adsorbent chamber, thereby it is possible to
restrain deterioration of the activated carbon in the main
adsorbent chamber.
[0017] In the second aspect of the present invention, the evaporate
gas from the fuel tank can easily flow into the second chamber
having a lower air-flow resistance, thereby it is possible to
further restrain deterioration of the activated carbon in the main
adsorbent chamber.
[0018] Further, in the third and ninth aspects of the present
invention, pulverized coal having a fine particle size is used as
the activated carbon in the second chamber so as to enhance the
adsorbing function while the time variation in the fuel
concentration of purged gas can be further decreased, thereby it is
possible to carry out more satisfactory operation of the engine.
Further, granulated coal having a large particle size is used as
the activated carbon in adsorbing chambers other than the second
chamber, so that the air-flow resistances of these chambers become
smaller. As a result, it is possible to enhance the adsorbing
functions of activated carbon, for evaporated gas flowing into the
canister through the tank port during fuel supply without
substantially increasing the overall air-flow resistance of the
canister.
[0019] Further, in the fourth, fifth, tenth and eleventh aspects of
the present invention, the evaporated fuel (vapor) surely flows in
the second chamber so as to be restrained from being adsorbed to
the activated carbon in the main adsorbent chamber for fuel supply
during running of a vehicle. Further, although air including a
large quantity of fuel vapor, which is generated when supplying
fuel, flows into the tank port, the air is smoothly discharged from
the atmospheric port with no substantial affection by a pressure
loss through the filter since the inflow pressure thereof is high.
Thus, no automatic stop of fuel supply is caused up to a
predetermined quantity of fuel.
[0020] Further, in the sixth aspect of the invention, the activated
carbon contained in the second chamber is packed so as to be easily
inserted inward of the chamber during assembly, thereby it is
possible to enhance the assembling ability. Further, it is possible
to prevent the activated carbon to be contained in the main
adsorbent chamber or the like from being erroneously contained in
the second chamber or being mingled with another kind of activated
carbon. This configuration is effective in such a case that the
activated carbon in the second chamber is different in kind from
that in the main adsorbent chamber or the like.
[0021] Further, in the seventh and thirteenth aspects of the
present invention, the quantity of activated carbon in the second
chamber can be optimized thereby it is possible to materialize a
canister which is inexpensive and which can be easily installed in
a vehicle. Should the quantity of activated carbon in the second
chamber be less, the function making the variation of the fuel
concentration of the purged gas fed into the engine gentle in time
would become insufficient, but should it be larger, the canister
has to have a large size and become expensive, and the installation
in the vehicle is uneasy.
[0022] Further, in the eighth and fourteenth aspects of the present
invention, evaporated fuel gas which is heavier than the air can
hardly flow into the main adsorbent chamber, but can easily flow
into the second chamber, thereby it is possible to restrain the
so-called blow-off of evaporated fuel gas from the canister. Thus,
it is possible to further restrain the activated carbon in the main
adsorbent layer from deteriorating.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a view illustrating an overall configuration of an
evaporated fuel treating equipment in an embodiment 1 according to
the present invention, in which a canister is shown in a vertical
section view;
[0024] FIG. 2A is a sectional view along line IIA-IIA in FIG.
1;
[0025] FIG. 2B is a sectional view along line IIB-IIB in FIG.
2A;
[0026] FIG. 3 is a view for explaining a grain size distribution of
pulverized coal and granulated coal;
[0027] FIG. 4 is a view for explaining a relationship between
activated carbon to be used and an air-flow resistance;
[0028] FIG. 5 is a view for explaining activated carbon to be used
and a working capacity;
[0029] FIG. 6 is a view illustrating an overall configuration of an
evaporated fuel treating equipment in an embodiment 2 according to
the present invention, in which a canister is shown in a vertical
sectional view;
[0030] FIG. 7 is a view illustrating an overall configuration of an
evaporated fuel treating equipment in an embodiment 3 according to
the present invention, in which a canister is shown in a vertical
sectional view;
[0031] FIG. 8A is a sectional view along line VIIIA-VIIIA in FIG.
7;
[0032] FIG. 8B is a sectional view along line VIIIB-VIIIB in FIG.
8A;
[0033] FIG. 9 is a vertical sectional view illustrating a canister
in an embodiment 4 according to the present invention;
[0034] FIGS. 10A to 10D are views illustrating a purge buffer plate
in the canister shown in FIG. 9, among which FIG. 10A is a view as
viewed from the left side of FIG. 9, FIG. 10B is a sectional view
illustrating along line XB-XB in FIG. 10A, FIG. 10C is view as
viewed from the right side of FIG. 10A, FIG. 10D is a view as
viewed from the bottom side of FIG. 10C;
[0035] FIG. 11 is a view illustrating a purge buffer plate in the
canister shown in FIG. 9, as viewed from the right side of FIG.
9;
[0036] FIG. 12 is a vertical sectional view for explaining a flow
of evaporated gas (vapor) in the embodiment 4 of the present
invention;
[0037] FIG. 13 is a vertical sectional view for explaining a flow
of evaporated gas in the embodiment 4 of the present invention;
[0038] FIG. 14 is a vertical sectional view illustrating the flow
during purge in the embodiment 4 of the present invention; and
[0039] FIG. 15 is a vertical sectional view illustrating a canister
in an embodiment 6 according to the present invention;
[0040] FIGS. 16A to 16B are view illustrating a subassembly of a
purge buffer plate, and three filters and a adsorbent retaining
plate in the canister shown in FIG. 15, among which FIG. 16A
illustrates the subassembly as viewed from the right side of FIG.
15, and FIG. 16B is a sectional view along line XVIB-XVIB in FIG.
16A.
DETAILED EXPLANATION OF PREFERRED EMBODIMENT OF THE INVENTION
Embodiment 1
[0041] Referring to FIGS. 1, 2A and 2B which shows an embodiment 1
according to the present invention, in which FIG. 1 is a schematic
view illustrating an overall configuration of an evaporated fuel
treating equipment in the embodiment 1, in which a canister is
shown in a vertical section view, FIG. 2A is a sectional view along
line IIA-IIB in FIG. 1, and FIG. 2B is a sectional view line
IIB-IIB in FIG. 2A.
[0042] The canister 1 has a casing 2 with a tank port 3, which is
communicated with an upper air chamber in a closed fuel tank 5
through the intermediary of a solenoid valve 4. The casing 2 also
is provided with a purge port 6, which is connected to an intake
passage of an engine 8 through the intermediary of a purge control
valve (VSV) 7. An electronic control unit (ECU) 9 controls the
solenoid valve 4 and the purge control valve 7. There is also shown
an atmospheric port (atmospheric hole) 10.
[0043] Between the tank port 3 and the purge port 6, a partition
plate 11 for preventing both ports from being directly communicated
with each other is integrally incorporated with the casing 2.
Further, there are shown a main adsorbent chamber 12 filled therein
with activated carbon 13 serving as adsorbent, adsorbent retaining
filters 14, 15, and an adsorbing retaining plate 16. Further, there
are first and second subchambers 17, 18 filled therein with
activated carbon 19, 20, respectively, adsorbent retaining filters
21, 22, 23 and 24, an adsorbing retaining plate 25, and springs 26,
27 for urging the plates 16, 25 against the filters 15, 21. An
atmospheric buffer plate 23A for partitioning between the first
subchamber 17 and the second subchamber 18 is provided between the
filters 22, 23. Since both subchambers 17, 18 are partitioned from
each other, the diffusion of vapor can be prevented.
[0044] Further, there are shown a first chamber 28 formed between
the main adsorbent chamber 12 and the tank port 3 and serving as an
air chamber with no activated carbon being contained therein, a
second chamber 29 formed between the main adsorbent chamber 12 and
the purge port 6, and filled therein activated carbon 30 as
adsorbent, fitters 31, 32, 33, and a purge buffer plate 34. The
purge buffer plate is located between the filters 14, 33, and
secured to the casing 2, and comprises a passage 34a for
communicating between the first chamber 28 and the second chamber
29 through the intermediary of the filter 33.
[0045] During fueling the fuel tank 5, the solenoid valve 4 is
opened, and accordingly, evaporated gas from the tank 5 flows
through the tank port 3 as indicated by the arrow C in FIG. 1, and
flows through the filter 31, the first chamber 28, the filter 33,
the buffer plate 34 and the filter 14 and into the main adsorbent
chamber 12 where it is adsorbed to the activated carbon 13 serving
as adsorbent. The remaining air flows through the first subchamber
17 and the second subchamber 18, and is then discharged into the
atmosphere from the atmospheric port 10. At this time, the
evaporated gas which has not yet been adsorbed to the activated
carbon 13 is adsorbed to the activated carbon 19, 20 and the
like.
[0046] Evaporated gas during running of the vehicle or at a high
pressure in the fuel tank, flows as indicated by the arrow D. That
is, the evaporated gas flows from the first chamber 28, through the
intermediary of the filter 33, the passage 34a in the buffer plate
34 and the filter 33, into the second chamber 29, and further
passes through the filter 32, and flows through the intermediary of
the purge port 6 and the purge control valve (VSV) 7, and then, is
fed into an intake passage of the engine 8. The purge control valve
7 is duty-controlled by the ECU 9. Further, as to the flow of
evaporated fuel during the so-called purge, evaporated gas which
has been adsorbed to activated carbon 20, 29, 13, is purged
(removed) by the stream of air flowing into the canister from the
atmospheric port as indicated by the arrow E, and is fed into the
intake passage of the engine 8.
[0047] Evaporated gas having a large variation in fuel
concentration (time variation in fuel concentration), which is
introduced into the tank port 3 from the closed fuel tank 5 through
the opened solenoid valve 4, is changed to have the gentle time
variation in fuel concentration by adsorption and purge action of
the activated carbon 30 in the second chamber 29. That is, the
variation in fuel concentration of the purged gas fed into the
engine becomes less. Thus, abrupt variation in engine air-fuel
ratio is restrained, thereby satisfactory engine operation can be
carried out. The total air-flow resistance of the filter 33 between
the first chamber 28 and the main adsorbent chamber 12, the buffer
plate 34 and the filter 14 is set to be higher than the air-flow
resistance of the purge buffer plate 34 between the first and
second chambers, i.e., the total air-flow resistance of the filter
33 and the passage 34a, so as to restrain the quantity of
evaporated gas flowing into the main adsorbent chamber 12 from the
tank port 3, thereby it is possible to restrain the activated
carbon in the main adsorbent chamber 12 from being
deteriorating.
[0048] The volume of the second chamber 29 or the capacity of the
purge buffer activated carbon 30 is appropriately set to about 100
mL in comparison with the capacity of the fuel tank 5 which is 70
L, but should be set to not less than 50 mL which is a half
thereof, as a minimum necessary capacity corresponding to 1/1,400
of the fuel tank capacity which is 70 L in order to obtain a
sufficient blunting effect. The larger the volume (capacity) of the
second chamber 29, the higher the blunting effect, but the size of
the canister becomes larger, and the mounting ability thereof onto
the vehicle becomes lower and as well the cost thereof becomes
higher. Thus, it is preferable to restrain the capacity of the
second chamber 29 to about 10/1,400 of the capacity of the fuel
tank.
[0049] The activated carbon serving as the adsorbent is classified,
as seen in FIG. 3, into pulverized coal distributed in a granular
size range from 0.7 to 2.0 mm and granulated coal distributed in a
granular size range from 2.0 to 2.5 mm. Although the air-flow
resistance of the canister becomes low as shown in FIG. 4 if the
granulated coal having a large granular size is used as all
activated carbon, that is, the activated carbon 30 in the second
chamber, the activated carbon 13 in the main adsorbent chamber 12
and the activated carbon 19, 20 in the first and second subchambers
17, 18, the working capacity becomes small as shown in FIG. 5.
[0050] On the contrary, if the pulverized coal having a small
granular size is used as all activated carbon, the air-flow
resistance of the canister becomes higher as shown in FIG. 4, but
the working capacity becomes larger (better) as shown in FIG.
5.
[0051] Thus, when the pulverized coal having a small granular size
is used as the activated carbon in the second chamber 29, and
granulated coal having a large granulated size is used as the
activated carbon 13, 19, 20 in the other chambers, the absorption
of the activated carbon in the second chamber 29 is increased so as
to further decrease the time variation in fuel concentration of the
purged gas and to restrain abrupt variation in engine air-fuel
ratio, thereby carrying out satisfactory engine operation.
[0052] The air-flow resistance of the activated carbon in the other
chamber can be decreased by using the granulated coal having a
large granular size, and accordingly, the evaporated gas which
flows into the canister from the tank port during fueling can be
adsorbed to the activated carbon in the main adsorbent chamber 12
and the subchambers 17, 18 without substantially increasing the
overall air-flow resistance of the canister. Thereby, it is
possible to obtain good fuel supply performance and good adsorption
performance with each other during fueling.
Embodiment 2
[0053] Referring to FIG. 6 which shows an embodiment 2 according to
the invention, this embodiment has the same configuration as that
of the embodiment 1, except that the activated carbon 30 contained
in the second chamber 29 is packed by a filter member 35 wrapping
it while the activated carbon 13, 19, 20 are not packed. In order
to assembly the packed activated carbon 30 wrapped with the filter
member 35 as shown in FIG. 6, the casing 2 is configured such that
a cover 2A is finally secured by welding to the right side of the
casing 2 as viewed in the figure.
[0054] In this embodiment 2, the same reference numerals are used
to denote parts having the same functions as that of those in the
embodiment 1 so as to abbreviate the explanation thereof. Further,
the arrows showing the flow of the evaporated gas and the like are
similar to those of the embodiment 1, and accordingly, which are
not shown for the brevity of the figure.
Embodiment 3
[0055] Referring to FIGS. 7, 8A and 8B which show an embodiment 3
of the invention, the configuration of the embodiment 3 is the same
as that of the embodiment 1, except that the shape of the purge
buffer plate 34, in particular, the shape of the passage 34a, is
different from that of the embodiment 1. Thus, the same reference
numerals are used to denote the same parts as those in the
embodiment 1 in order to abbreviate the explanation thereto.
[0056] In this embodiment 3, the passage 34a communicating between
the first chamber 28 and the second chamber 29 is located on the
upper side of the purge buffer plate 34 in the posture the canister
1 installed in the vehicle, and accordingly, the evaporated gas
(vapor) having flown into the first chamber 28 from the tank port 3
can hardly flow into the main adsorbent chamber 12 but can smoothly
flow into the second chamber 29.
Embodiment 4
[0057] Referring to FIGS. 9 to 14 which show a specific
configuration of a canister in an embodiment 4 according to the
invention, the same references are used to denote parts having the
same functions as those in the embodiment 1 so as to abbreviate the
explanation thereto. It is noted that the same reference numerals
are used to denote parts having the same functions as those in the
embodiments 1 to 3 although the shapes of elements in the
embodiment 4 are different in details in comparison with the
embodiments 1 to 3 which schematically indicate the overall
configuration thereof.
[0058] In this embodiment 4, the purge buffer plate 34 is also
located between the filters 14 and 33, and comprises a passage 34a
communicating between the first chamber 28 and the second chamber
29. This buffer plate 34 incorporates twenty eight pieces of
retaining pins 34e having a height h as shown in FIGS. 10B and 11.
These retaining pins 34e are adapted to retain the filter 14 as
shown in FIG. 9. Further, the passage 34a in the buffer plate 34 is
formed therein with fifteen rectangular openings 34b opened to the
first chamber 28 and with seven circular openings 34c opened to the
second chamber 29. Moreover, four positioning pins 34d for holding
the filter 33 are projected from one of surfaces of the buffer
plate 34.
[0059] It is noted that there is shown, in FIG. 9, a member 33A
which is a filter superposed on one of the surfaces of the filter
33 (on the second chamber 29 side), and having an air-flow
resistance set to be higher than that of the filter 33, and which
has such a function that the vapor can be smoothly diffused through
in the filter 33 upon flowing thereof.
[0060] FIGS. 12, 13 and 14 show the arrows C, D and E indicating
flows of evaporated gas (vapor) in FIG. 9, corresponding
respectively to the flows C, D and E shown in FIG. 1. In FIGS. 13
and 14, it can be understood that the evaporated gas is diffused
widely in the filter 33 under the action of the filter 33A, and
accordingly, it can be uniformly spread over the activated carbon
30 in the second chamber 29. Thus, the adsorption and purge of the
vapor to and from the activated carbon 30 can be effectively
carried out it is further noted that only reference numbers of the
components associated with the explanation of the vapor flows with
the arrows C, D, E are described in FIGS. 12 to 14, and the
reference numerals of the components which are not substantially
associated with this explanation are not describe therein in order
to avoid complication of the figures.
[0061] This embodiment 5 is directed to the fourth and tenth
aspects of the invention. In FIGS. 7, 8A and 8B, the air-flow
resistance of the filter 14 provided in the main adsorbent chamber
12 on the tank port 3/purge port 6 side is set per unit area to be
higher than that of the filter 32 in the second chamber 29 on the
purge port 6 side and of the filter 33 provided in the second
chamber 29 on the main adsorbent chamber 12 side.
[0062] During fueling, although air containing a large quantity of
fuel vapor generated in the fuel tank flows into the canister from
the tank port, the air can be smoothly discharged from the
atmospheric port with little affection by a pressure loss through
the filter 14 because of the high flow rate of the air. Thus,
during fueling, no automatic stop of fuel at a fuel supply nozzle
would occur until the fuel is supplied up to a predetermined
quantity.
[0063] Since the flow rate is controlled by opening and closing the
solenoid valve during running of the vehicle, although no large
quantity of fuel vapor flows into the canister through the tank
port, the fuel vapor is surely led into the purge line (or the
intake passage of the engine) from the filter 33 since the air-flow
resistance of the filter 14 is set to be higher, thereby it is
possible to prevent the fuel vapor from being adsorbed to the
activated carbon 13 in the main adsorbent chamber 12. It is noted
that a relatively high effect in which the fuel vapor surely flows
into the purge line from the fuel tank so as to prevent the fuel
vapor from being adsorbed to the activated carbon in the main
adsorbent chamber 12, can be obtained by setting the air-flow
resistance of the filter 14 to be higher than that of the filter
33.
Embodiment 6
[0064] Referring to FIGS. 15, 16A and 16B which show an embodiment
6 according to the invention, the configuration of the embodiment 6
is the same as that of the embodiment 4 shown in FIGS. 9 to 14,
except that an adsorbent retaining plate 14A is additionally
incorporated. Referring to FIG. 15, the adsorbent retaining plate
14A is superposed with the filter 14 on the right side of FIG. 15,
and is formed therein with five constriction holes 14a. The total
air-flow resistance of the filter 14 and the adsorbent retaining
plate 14a which are superposed with each other is set per unit area
to be higher than that of the filter 32 provided in the second
chamber 29 on the purge port 6 side and of the filter 33, 33A
provided in the second chamber 29 on the main adsorbent chamber 12
side.
[0065] Incidentally, in FIG. 15, instead of superposing the
adsorbent retaining plate 14A with the filter 14 on the right side
thereof in the drawing, the adsorbent retaining plate may be
superposed with the filter on the left side thereof in the drawing.
Further, there may be provided one or more of the constriction
holes.
[0066] It is noted that the same reference numerals in the
embodiment 6 shown in FIGS. 15, 16A and 16B are used to denote
parts having the same functions as that in the embodiment 4 shown
in FIGS. 9 to 14.
[0067] As stated above, the present invention can be used in an
evaporated fuel treating equipment for an internal combustion
engine using a closed fuel tank.
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