U.S. patent application number 09/885156 was filed with the patent office on 2002-03-14 for evaporated fuel discharge preventing apparatus.
Invention is credited to Sakakibara, Hitoshi, Toki, Tomonari, Yamada, Hideo.
Application Number | 20020029693 09/885156 |
Document ID | / |
Family ID | 18688326 |
Filed Date | 2002-03-14 |
United States Patent
Application |
20020029693 |
Kind Code |
A1 |
Sakakibara, Hitoshi ; et
al. |
March 14, 2002 |
Evaporated fuel discharge preventing apparatus
Abstract
An evaporated fuel discharge preventing apparatus, in order to
sufficiently adsorb and collect an evaporated fuel generated in an
intake air passage at a time when an engine stops, and to prevent
an engine performance from being reduced by reducing an intake air
resistance in an evaporated fuel adsorbing portion at a time when
the engine is driven, has an adsorbing device arranged in a passage
between an evaporated fuel generating portion and an air cleaner
element, and, the adsorbing device is formed by an intake air
passage portion laterally arranged within the device penetratingly
and communicated with the passage at both ends, an adsorbent layer
arranged on an outer periphery of the intake air passage portion,
and a member covering an outer surface in a non-ventilating state
except a side of the intake air passage portion in the adsorbent
layer, and an inner diameter of the intake air passage portion of
the adsorbing device is set to be substantially equal to or more
than an inner diameter of the intake air passage.
Inventors: |
Sakakibara, Hitoshi;
(Ohbu-shi, JP) ; Toki, Tomonari; (Ohbu-shi,
JP) ; Yamada, Hideo; (Ohbu-shi, JP) |
Correspondence
Address: |
Pillsbury Madison & Sutro LLP
Intellectual Property Group
East Tower
1100 New York Avenue, N.W., Ninth Floor
Washington
DC
20005-3918
US
|
Family ID: |
18688326 |
Appl. No.: |
09/885156 |
Filed: |
June 21, 2001 |
Current U.S.
Class: |
96/134 ; 123/519;
55/385.3; 96/143 |
Current CPC
Class: |
B01D 2279/60 20130101;
B01D 46/62 20220101; B01D 2253/108 20130101; B01D 46/0036 20130101;
Y10S 55/19 20130101; B01D 53/0407 20130101; B01D 46/30 20130101;
B01D 46/521 20130101; B01D 2253/102 20130101; B01D 2253/104
20130101; B01D 2253/106 20130101; B01D 46/10 20130101; B01D 53/04
20130101; B01D 53/0446 20130101; F02M 35/0218 20130101; B01D
2259/4566 20130101; F02M 25/0854 20130101; B01D 2259/4516
20130101 |
Class at
Publication: |
96/134 ; 96/143;
55/385.3; 123/519 |
International
Class: |
B01D 053/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2000 |
JP |
2000-188559 |
Claims
What is claimed is:
1. An evaporated fuel discharge preventing apparatus comprising: an
evaporated fuel generating portion; an air cleaner element; and an
adsorbing device arranged in a passage between the evaporated fuel
generating portion and the air cleaner element, wherein said
adsorbing device is formed by an intake air passage portion
laterally arranged within the device penetratingly and communicated
with said passage at both ends, an adsorbent layer arranged on an
outer periphery of said intake air passage portion, and a member
covering an outer surface in a non-ventilating state except a side
of said intake air passage portion in said adsorbent layer, and an
inner diameter of the intake air passage portion of said adsorbing
device is set to be substantially equal to or more than an inner
diameter of said intake air passage.
2. An evaporated fuel discharge preventing apparatus as claimed in
claim 1, wherein said adsorbent layer is provided only on a
substantially lower half portion of an outer periphery of the
intake air passage portion.
3. An evaporated fuel discharge preventing apparatus as claimed in
claim 1, wherein a thickness of the adsorbent layer in a direction
perpendicular to an axis of said intake air passage portion is
larger on a side of a lower portion and smaller on a side of an
upper portion.
4. An evaporated fuel discharge preventing apparatus as claimed in
claim 1, wherein a filter is provided between said intake air
passage portion and said adsorbent layer and said filter is bent in
a wave shape.
5. An evaporated fuel discharge preventing apparatus as claimed in
claim 2, wherein a filter is provided between said intake air
passage portion and said adsorbent layer and said filter is bent in
a wave shape.
6. An evaporated fuel discharge preventing apparatus as claimed in
claim 3, wherein a filter is provided between said intake air
passage portion and said adsorbent layer and said filter is bent in
a wave shape.
Description
FIELD OF THE INVENTION
[0001] The invention relates to an evaporated fuel discharge
preventing apparatus.
DESCRIPTION OF RELATED ART
[0002] As an apparatus for preventing an evaporated fuel from being
discharged into an atmospheric air by providing an evaporated fuel
adsorbing element in an air cleaner portion for adsorbing and
collecting the evaporated fuel evaporated from an internal
combustion engine or the like at a time when the internal
combustion engine stops, there has been conventionally provided a
structure as shown in FIG. 7, in which an air cleaner case 102 is
provided on an upper portion of an air cleaner chamber 101
communicating with an intake manifold and a blow-by gas
introduction pipe (these elements are not illustrated), and a
cylindrical evaporated fuel adsorbing element 103 and a cylindrical
air cleaner element 104 are provided within the air cleaner case
102 in such a manner that respective axes extend in a vertical
direction and the former is arranged on a lower side of the latter,
thereby adsorbing and collecting the evaporated fuel generated at a
time when the internal combustion engine stops by the evaporated
fuel adsorbing element 103, and purging the evaporated fuel
adsorbed and collected in the evaporated fuel adsorbing element 103
in accordance with the atmospheric air stream as shown by arrows A
in FIG. 7 generated by an intake negative pressure at a time when
the engine is driven. This structure is disclosed, for example, in
JP-U-61-183456 and JP-U-61-194761. This is set to a first prior
art.
[0003] Further, as shown in FIG. 8, there has been provided a
structure in which an air cleaner main body 201 is disposed
laterally, a filter 202 and an adsorbent 203 are arranged in series
within the air cleaner main body, and a passage 204 is provided on
an outer peripheral portion of the adsorbent 203, adsorbing and
collecting the evaporated fuel by the adsorbent 203 at a time when
the engine stops and flowing the atmospheric air within the
adsorbent 203 as arrows B in FIG. 9 at a time when the engine is
driven so as to purge the evaporated fuel collected within the
adsorbent 203. This structure is disclosed, for example, in
JP-U-58-113861. This is set to a second prior art.
[0004] In this case, the element 103 and the adsorbent 203
adsorbing the evaporated fuel as mentioned above are structured
such that an amount of transmitting air is less than an amount of
transmitting air of the air cleaner elements 104 and 202 in order
to prevent the evaporated fuel adsorbed and collected in the
element 103 and the adsorbent 203 from being purged at a large
amount for a short time at a time when the engine is driven.
[0005] Accordingly, in the first prior art mentioned above, since a
part of the air sucked at a time when the engine is driven passes
through the evaporated fuel adsorbing element 103 having a little
amount of transmitting air, an airflow resistance is increased and
there is a risk that a performance of the internal combustion
engine is reduced.
[0006] Further, in the second prior art mentioned above, since most
of the sucked air passes through the adsorbent 203, there is also a
risk that a performance of the internal combustion engine is
reduced in the same manner as that of the first prior art.
[0007] Accordingly, an object of the present invention is to
provide an evaporated fuel discharge preventing apparatus which can
sufficiently adsorb and collect an evaporated fuel without causing
a reduction of engine performance as mentioned above.
SUMMARY OF THE INVENTION
[0008] In order to solve the problems mentioned above, in
accordance with the present invention, there is provided an
evaporated fuel discharge preventing apparatus comprising:
[0009] an evaporated fuel generating portion;
[0010] an air cleaner element; and
[0011] an adsorbing device arranged in a passage between the
evaporated fuel generating portion and the air cleaner element,
[0012] wherein the adsorbing device is formed by an intake air
passage portion laterally formed within the device so as to pass
through and communicated with the passage at both ends, an
adsorbent layer arranged on an outer periphery of the intake air
passage portion, and a member covering an outer surface in a
non-ventilating state except a side of the intake air passage
portion in the adsorbent layer, and an inner diameter of the intake
air passage portion of the adsorbing device is set to be
substantially equal to or more than an inner diameter of the intake
air passage.
[0013] In accordance with the present invention, the evaporated
fuel and the blow-by gas (hereinafter, both thereof are also
referred to as evaporated fuel) generated within the intake air
passage or the evaporated fuel flowing out from an atmospheric port
of a canister or the like, at a time when the engine stops, slowly
flows within the intake air passage portion laterally disposed in
the adsorbing device. Accordingly, the evaporated fuel is adsorbed
and collected by the adsorbent layer arranged on the outer
periphery of the intake air passage portion.
[0014] When the engine is driven, an ambient air flows from the
side of the air cleaner through the intake air passage portion in
the adsorbing device so as to be supplied to the engine via the
intake air passage and the canister. At this time, the evaporated
fuel adsorbed and collected in the adsorbent layer in the adsorbing
device is sucked to the air (the ambient air) flowing through the
intake air passage portion in the adsorbing device and purged to
the engine together with the air.
[0015] Further, since the intake air flows within the intake air
passage portion without flowing through the adsorbent layer, and an
inner diameter of the intake air passage portion in the adsorbing
device is set to be substantially equal to or more than an inner
diameter of the front and rear passages, an intake air resistance
is significantly small in the adsorbing device portion with respect
to the air flowing within the passage. Accordingly, an engine
performance is not reduced by the intake air resistance.
[0016] Further, in the present invention, the adsorbent layer may
be provided only on a substantially lower half portion of the outer
periphery of the intake air passage portion.
[0017] Since the intake air passage portion of the adsorbing device
is arranged laterally, the evaporated fuel slowly flowing in a
lateral direction on the side of the lower portion in the intake
air passage portion at a time when the engine stops is mainly
adsorbed and collected to the adsorbent layer on the lower side of
the intake air passage portion.
[0018] Accordingly, as mentioned above, even in the case that the
adsorbent layer is provided only on the substantially lower half
portion of the outer periphery in the intake air passage portion,
it is possible to sufficiently adsorb and collect the evaporated
fuel. Further, it is possible to reduce a cost in comparison with
the structure in which the adsorbent layer is provided in all
around the periphery, by omitting the adsorbent layer on the upper
half portion.
[0019] Further, in the present invention, a thickness of the
adsorbent layer in a direction perpendicular to an axis of the
intake air passage portion on the side of the lower portion may be
large while that on the side of the upper portion may be small.
[0020] Accordingly, since the evaporated fuel is mainly adsorbed
and collected on the side of the lower portion of the adsorbent
layer, it is possible to increase an adsorbing and collecting
capacity of the evaporated fuel by increasing the thickness on the
side of the lower portion. Further, since the adsorbent layer is
also provided on the side of the upper portion of the adsorbing
passage portion, the evaporated fuel is adsorbed and collected even
in the adsorbent layer on the side of the upper portion.
Accordingly, the evaporated fuel can be further efficiently
adsorbed and collected.
[0021] Furthermore, in the present invention, a filter may be
provided between the intake air passage portion and the adsorbent
layer, and the filter may be bent in a wave shape.
[0022] With the structure, a surface area on the side of the intake
air passage portion in the adsorbent layer becomes larger than that
of a flat filter, whereby it is possible to increase an adsorbing
efficiency of the evaporated fuel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a schematic view showing an embodiment of an
evaporated fuel discharge preventing apparatus in accordance with
the present invention;
[0024] FIGS. 2A and 2B are cross sectional views showing a first
embodiment of an adsorbing device shown in FIG. 1, in which FIG. 2A
is a side cross sectional view and FIG. 2B is a cross sectional
view along a line IIB-IIB in FIG. 2A;
[0025] FIGS. 3A and 3B are cross sectional views showing a second
embodiment of an adsorbing device in accordance with the present
invention, in which FIG. 3A is a side cross sectional view and FIG.
3B is a cross sectional view along a line IIIB-IIIB in FIG. 3A;
[0026] FIGS. 4A and 4B are cross sectional views showing a third
embodiment of an adsorbing device in accordance with the present
invention, in which FIG. 4A is a side cross sectional view and FIG.
4B is a cross sectional view along a line IVB-IVB in FIG. 4A;
[0027] FIG. 5 is a side cross sectional view showing a fourth
embodiment of an adsorbing device in accordance with the present
invention;
[0028] FIG. 6 is a front cross sectional view showing a fifth
embodiment of an adsorbing device in accordance with the present
invention;
[0029] FIG. 7 is a vertical cross sectional view showing a
conventional evaporated fuel discharge preventing apparatus;
and
[0030] FIG. 8 is a vertical cross sectional view showing another
embodiment of a conventional evaporated fuel discharge preventing
apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] A description will be given of an embodiment in accordance
with the present invention on the basis of an example shown in the
accompanying drawings.
[0032] FIGS. 1 to 2B show a first embodiment in accordance with the
present invention, in which FIG. 1 shows an embodiment obtained by
applying the present invention to an intake air passage of an
evaporated fuel discharge preventing apparatus in an internal
combustion engine, and FIGS. 2A and 2B show details of an adsorbing
device for an evaporated fuel arranged in the apparatus.
[0033] In FIG. 1, an injector 3 for injecting a fuel is provided in
an intake air manifold 2 corresponding to an intake air passage of
an internal combustion engine 1, and a surge tank 4 is provided in
an upstream of the intake air manifold 2. One end of a first hose 5
in a blowby gas reducing system is communicated with the surge tank
4 by an outflow port 5a. Another end of the first hose 5 is
communicated with a crank case of the internal combustion engine 1
via a PCV valve (not shown).
[0034] A throttle body 7 having a throttle valve 6 built-in is
arranged on an upstream side of the surge tank 4 (with respect to a
direction of flow of the intake air), and one end of a second hose
9 in the blowby gas reducing system is communicated with and open
to an intake air passage 8 on an upstream side of the throttle body
7 by an outflow port 9a. Another end of the second hose 9 is
communicated with an inside of the crank case of the internal
combustion engine.
[0035] An adsorbing device 10 for an evaporated fuel is
communicated with and arranged in the intake air passage on an
upstream side from an evaporated fuel generating source of the
injector 3 and the outflow ports 5a and 9a in the first and second
hoses 5 and 9. The adsorbing device 10 is arranged so that an
intake air passage portion 11 therewithin becomes a transverse
passage, that is, an axis of the intake air passage portion 11
extends in a substantially horizontal direction. Further, the
intake air passage portion 11 is formed by a cylindrical filter 12,
and an inner diameter RI of the intake air passage portion 11
constituted by an inner surface of the cylindrical filter 12 (more
particularly, an inner surface of an inner cylindrical portion 18
shown in FIGS. 2A and 2B) is set to be substantially equal to or
more than an inner diameter R2 of the intake air passage 8 to which
the second hose 9 is open and an intake air passage 13 on a side of
an air cleaner 14. That is, a flow cross sectional area of the
intake air passage portion 11 is set to be substantially equal to
or more than a flow cross sectional area of the intake air passage
8 and a flow cross sectional area of the intake air passage 13 in
the side of the air cleaner.
[0036] The air cleaner 14 is arranged on an upstream side of the
adsorbing device 10 for the evaporated fuel, and an air cleaner
element 15 is provided therewithin. The air cleaner element 15 is
provided on an upstream side with an atmospheric air intake port
16, and is communicated on a downstream side with the adsorbing
device 10 for the evaporated fuel through the intake air passage
13, as mentioned above.
[0037] FIGS. 2A and 2B show details of the adsorbing device 10 for
the evaporated fuel.
[0038] A case 17 forming the adsorbing device 10 is constituted by
a cylindrical inner cylinder portion 18 forming the intake air
passage portion 11, and an outer cylinder portion 20 forming an
adsorbent receiving chamber 19 on an outer periphery thereof. A
connecting portion 18a is formed at an upstream end of the inner
cylinder portion 18. One end surface of the adsorbent receiving
chamber 19 is closed by a lid 21, and a connecting portion 21a is
formed in a center of the lid 21. Inner diameters of flow ports 22a
and 22b formed in both connecting portions 18a and 21a are formed
to have the same diameter as that of the intake air passage portion
11.
[0039] The outer cylinder portion 20 and the lid 21 form a member
covering an outer surface of an adsorbent layer 23 mentioned below
in a non-flow state.
[0040] A main portion of the inner cylinder portion 18 is
structured such that a plurality of narrow ribs 18b are arranged in
a peripheral direction so as to be directed in an axial direction,
and a plurality of introduction windows 18c each having a wide area
are formed between the ribs 18b in a peripheral direction.
[0041] The cylindrical permeable filter 12 is arranged and held on
an outer periphery of a plurality of ribs 18b, and an outer portion
of each of the introduction windows 18c is covered by the filter
12.
[0042] The adsorbent layer 23 formed by filling it with adsorbent
is provided within the adsorbent receiving chamber 19 formed on the
outer peripheral portion of the filter 12. The adsorbent within the
adsorbent layer 23 employs a carbonaceous porous material such as
an activated carbon or the like mainly containing a carbon, an
inorganic porous material such as a silica gel, a zeolite, an
activated alumina or the like, an organic polymer adsorbent, or the
like.
[0043] Next, a description will be given of an operation in the
first embodiment mentioned above.
[0044] At a time when the engine stops, an evaporated fuel slightly
leaking from the injector 3 to the intake air manifold 2 so as to
be evaporated, a blowby gas leaking from the outlet ports 5a and 7a
of the blowby gas reducing system to the surge tank 4 and the
intake air passage 8, and the like flow to the side of the
adsorbing device 10 for the evaporated fuel at a slow speed
corresponding to a speed of diffusion and a volume changing speed
level of the air within the intake air passage, and slowly flow in
a direction of the air cleaner 14 within the intake air passage
portion 11 in the adsorbing device 10. Due to the stream at the
slow speed, the evaporated fuel and the blowby gas transmit through
the filter 12 from the introduction windows 18c and enter the
adsorbent layer 23 so as to be adsorbed and collected by the
adsorbent. Accordingly, it is not necessary to make the gas
containing the evaporated fuel and the blowby gas positively pass
through the inner portion of the adsorbent layer 23. That is, it is
possible to sufficiently adsorb and collect the evaporated fuel
only by passing through the inner peripheral surface side of the
adsorbent layer 23.
[0045] In the case that the engine is driven, when the throttle
valve 6 is opened, the ambient air flows into the intake air
passage 8 through the intake air passage portion 11 of the
adsorbing device 10 from the side of the air cleaner 14 in a
straight manner, and is further supplied to the engine 1. Due to
the air intake, the evaporated fuel, the blowby gas and the like
collected in the adsorbent layer 23 of the adsorbing device 10 are
drawn out by the intake air mentioned above so as to be purged to
the engine.
[0046] At such a time of sucking when the engine is driven, since a
diameter (a flow area) of the intake air passage portion 11 in the
adsorbing device 10 is set to be substantially equal to or more
than a diameter (a flow area) of the intake air passages 8 and 13
disposed in front and at the rear thereof, and the intake air
passage portion 11 is formed in a straight shape, an intake air
resistance in the adsorbing device 10 is significantly small, so
that an intake operation of the engine is not disturbed and an
engine performance is not reduced.
[0047] FIGS. 3A and 3B show a second embodiment in accordance with
the present invention.
[0048] The second embodiment is structured such that the adsorbent
layer 23 in the adsorbing device 10 for the evaporated fuel is
provided only in a substantially lower half portion of the intake
air passage portion 11. That is, a substantially upper half portion
of the inner cylinder portion 18 in the first embodiment is formed
as a nonporous wall portion 18d, and the same ribs 18b and
introduction windows 18c as those of the first embodiment are
formed in the substantially lower half portion. Further, an upper
half portion of the outer cylinder portion 20 in the first
embodiment is omitted such that a substantially semicircular
adsorbent receiving chamber 19 is formed between the substantially
semicircular outer cylinder portion 20 disposed on the lower side
and the inner cylinder portion 18, and the adsorbent layer 23 is
provided within the adsorbent receiving chamber 19 with interposing
the filter 12.
[0049] The other structural components are the same as those of the
first embodiment mentioned above.
[0050] The adsorbing device 10 is connected and arranged between
the front and rear intake air passages 8 and 13 shown in FIG. 1 and
in the transverse direction as the first embodiment in a state of
arranging the adsorbent receiving chamber 19 on the lower side of
the adsorbing device.
[0051] In the present second embodiment, in addition to the same
operation and effect as those of the first embodiment mentioned
above, the following effects can be obtained.
[0052] Since the evaporated fuel is normally heavier than air, the
evaporated fuel flows on the lower side in the intake air passage
portion 11 and the air flows on the upper side when the gas
containing the evaporated fuel passes through the inner portion of
the intake air passage portion 11 in the manner mentioned above.
Accordingly, the evaporated fuel is mainly adsorbed and collected
in the adsorbent layer 23 which is positioned in an area lower than
a center of the intake air passage portion 11.
[0053] Thus, by arranging the adsorbent layer 23 only in the
portion positioned at the substantially lower half portion of the
intake air passage portion 11 as shown in FIGS. 3A and 3B, it is
possible to sufficiently collect the evaporated fuel and prevent
the adsorbent from being wastefully used, so that it is possible to
reduce a cost and a weight of the adsorbing device 10.
[0054] FIGS. 4A and 4B show a third embodiment in accordance with
the present invention.
[0055] The third embodiment is structured such that the outer
cylinder portion 20 in the first embodiment is arranged so that an
axis of the outer cylinder portion 20 is downward eccentric with
respect to the axis of the inner cylinder portion 18, so as to form
the adsorbent receiving chamber 19 in such a manner that an upper
portion thereof is narrow and a lower portion thereof is wide,
thereby making a thickness of the adsorbent layer 23 in a direction
perpendicular to the axis of the intake air passage portion 11 thin
on an upper side and thick on a lower side.
[0056] The other structural components are the same as those of the
first embodiment mentioned above.
[0057] In the third embodiment, since the adsorbent layer 23 is
mainly arranged in the lower portion, it is possible to effectively
adsorb and collect the evaporated fuel in the same manner as the
second embodiment so as to reduce a cost. In addition, in the third
embodiment, since the adsorbent layer 23 is arranged on the upper
side, an amount of which is smaller than that on the lower side, it
is possible to adsorb and collect the evaporated fuel passing
through the upper side, whereby it is possible to intend to improve
an adsorbing and collecting efficiency.
[0058] FIG. 5 shows a fourth embodiment according to the present
invention.
[0059] The present fourth embodiment is structured such that the
filter 12 in the first embodiment shown in FIGS. 2A and 2B is bent
in a waveform in an axial direction of the intake air passage
portion 11.
[0060] The other structural components are the same as those of the
first embodiment.
[0061] In accordance with the present fifth embodiment, in addition
to the same operation and effect as those of the first embodiment
mentioned above, it is possible to increase a surface area on the
side surface of the intake air passage portion 11 in the adsorbent
layer 23 in comparison with the structure shown in FIGS. 2A and 2B
so as to further increase a collecting efficiency for the
evaporated fuel. Accordingly, it is possible to reduce a capacity
of the adsorbent and make the structure light and compact.
[0062] Further, since the filter 12 is provided on the outer
peripheral portion of the introduction windows 18c in the inner
cylinder portion 18, that is, out of the intake air passage portion
11 even in the case of being bent in a waveform, the filter 12 does
not constitute a large flowing resistance.
[0063] FIG. 6 shows a fifth embodiment according to the present
invention.
[0064] The present fifth embodiment is structured such that the
filter 12 in the first embodiment shown in FIGS. 2A and 2B is bent
in a waveform in a peripheral direction of the intake air passage
portion 11 .
[0065] The other structural components are the same as those of the
first embodiment mentioned above.
[0066] In the present fifth embodiment, it is also possible to
obtain the same operation and effect as those of the fourth
embodiment mentioned above.
[0067] In this case, the filters 12 in the embodiments shown in
FIGS. 3A, 3B and FIGS. 4A and 4B may be bent in a waveform as shown
in FIGS. 5 and 6.
[0068] Incidentally, the present invention is not limited to the
embodiments mentioned above, and the adsorbing device 10 may be
connected to an outlet portion of the atmospheric air port in the
canister arranged in the evaporated fuel discharge preventing
apparatus. In this case, the canister constitutes the evaporated
fuel generating portion, and the evaporated fuel discharged from
the canister through the atmospheric air port is adsorbed and
collected by the adsorbing device 10. In this case, it is also
possible to obtain the same operation and effect as those of the
embodiments mentioned above.
[0069] Since the structure is made in the manner mentioned above,
in accordance with the present invention, it is possible to
sufficiently adsorb and collect the evaporated fuel at a time when
the engine stops, and significantly reduce the intake air
resistance in the adsorbing device portion at a time when the
engine is driven, so as to prevent the engine performance from
being reduced due to the intake air resistance.
[0070] Additionally, in accordance with the present invention, it
is further possible to achieve the effects mentioned above and
reduce the cost of the adsorbing device by providing the adsorbent
layer only on the substantially lower half portion in the outer
periphery of the intake air passage portion.
[0071] In addition, in accordance with the present invention, it is
further possible to more effectively adsorb and collect the
evaporated fuel by making the thickness of the adsorbent layer in
the direction perpendicular to the axis of the intake air passage
portion larger on the lower side and smaller on the upper side.
[0072] Moreover, in accordance with the present invention, it is
further possible to increase the adsorbing side surface in the
adsorbent layer so as to increase the adsorbing efficiency by
providing the filter between the intake air passage portion and the
adsorbent layer and bending the filter in the waveform.
* * * * *