JP4715727B2 - Evaporative fuel processing equipment - Google Patents

Description

  The present invention relates to a fuel vapor processing apparatus.

  In an evaporative fuel processing apparatus for processing evaporative fuel generated in a fuel tank or the like, evaporative fuel generated at the time of refueling and evaporation generated at the time of non-fuel supply such as operation (hereinafter, collectively referred to as “during operation” as appropriate) It is preferable to properly treat both fuels. For example, Patent Document 1 describes a configuration in which a low airflow resistance canister for oil supply that operates when refueling is provided in parallel with an evaporation canister that operates when oil is not supplied.

By the way, the evaporative canister inevitably increases the airflow resistance because it is filled with relatively fine activated carbon in the container in consideration of adsorption efficiency, and evaporative fuel generated during refueling is used for evaporation. Efficient adsorption with a canister is difficult.
Japanese Patent No. 3319108

  In view of the above facts, an object of the present invention is to obtain an evaporative fuel processing apparatus that can achieve downsizing while maintaining the processing performance of evaporative fuel generated during refueling.

  According to the first aspect of the present invention, a fuel canister for adsorbing evaporated fuel generated in the fuel tank when fuel is supplied to the fuel tank by the activated carbon, and a fuel canister that is arranged in parallel with the fuel canister for the fuel tank. Provided in correspondence with the canister for operation and the canister for operation where the evaporated fuel generated in the fuel tank is adsorbed by activated carbon both when refueling and when the fuel tank is not refueled, including during vehicle operation The blow-out prevention unit that prevents the vaporized fuel from blowing through from the operating canister unit to the atmosphere, the communication unit that communicates the operation canister and the blow-out prevention unit, and the ventilation resistance of the communication unit can be changed. Ventilation resistance variable means.

In this fuel vapor processing apparatus, when fuel is supplied to the fuel tank, the vapor switching valve is opened, and the ventilation resistance variable means also reduces the ventilation resistance of the communication means. To both the operation part and the canister part for operation. On the other hand, since the vapor switching valve is closed during operation, the evaporated fuel in the fuel tank is sent only to the operation canister. During operation, the variable airflow resistance means increases the airflow resistance of the communication means, so that it is possible to prevent the vaporized fuel from blowing through the canister for operation.
The activated carbon of the canister unit for refueling is set to have a small airflow resistance in accordance with the treatment of evaporated fuel generated in large quantities during refueling. In addition, the activated carbon of the canister for operation can be contacted with the evaporated fuel generated during operation by increasing the ventilation resistance by the ventilation resistance variable means and suppressing the evaporation of the evaporated fuel even if the ventilation resistance is reduced. The required adsorption performance can be secured by lengthening the time. Further, the canister unit for operation in which the airflow resistance is set to be small can cope with the processing of the evaporated fuel generated in large quantities at the time of refueling by reducing the airflow resistance by the airflow resistance variable means. That is, in the present invention, by reducing the airflow resistance of both the fueling canister unit and the driving canister, both of them can be used for adsorbing evaporated fuel during fueling. Compared to the configuration where only the fueling canister is used for adsorbing evaporated fuel during refueling, the fueling canister can be made smaller while maintaining the processing performance of the evaporated fuel. However, miniaturization can be achieved.

  In addition, in this fuel vapor processing apparatus, the blow-off prevention unit prevents the fuel vapor from blowing through from the operating canister unit to the atmosphere, so that a high processing capacity can be obtained as a whole of the fuel vapor processing apparatus. .

In particular, in the present invention, the canister unit for operation and the blow-through prevention unit communicate with each other by the communication means, and further, the canister unit for oil supply and the blow-through prevention unit communicate with each other by the communication unit.

Thereby, it is possible to prevent the evaporated fuel from being blown from the refueling canister to the atmosphere. In addition, since the blow-through prevention unit can be shared by both the oil supply canister unit and the operation canister unit , the structure can be reduced in size as compared with the configuration in which the blow-out prevention unit is separately provided. .

The invention according to claim 2 is characterized in that, in the invention according to claim 1 , the canister part for operation and the blow-off preventing part are arranged adjacent to each other.

  As a result, the refueling canister portion is disposed at a position relatively away from the blow-through prevention portion, and the return of the evaporated fuel from the blow-through prevention portion to the refueling canister portion can be prevented.

  Since the present invention is configured as described above, it is possible to achieve downsizing while maintaining the processing performance of the evaporated fuel generated during refueling.

  FIG. 1 shows a fuel vapor processing apparatus 12 according to a first embodiment of the present invention. The fuel vapor processing apparatus 12 has two housings, a first housing 14 and a second housing 16.

  Inside the first housing 14, filter membranes 18A and 18B made of a nonwoven fabric or the like are provided in parallel to the one end wall 14A and the other end wall 14B. The second housing 16 is also provided with filter membranes 20A and 20B made of a nonwoven fabric or the like in parallel with the one end wall 16A and the other end wall 16B.

  A partition wall 22 is provided in the first housing 14, and one space (space closer to the second housing 16) defined by the partition wall 22 and the two filter films 18A and 18B is, for example, An adsorbent 24 made of granular or pelleted activated carbon is filled into an ORVR canister section 26. Also, the other partitioned space (the space far from the second housing 16) is filled with an adsorbent 28 made of activated carbon that is equal to or larger than the size of the activated carbon used for the adsorbent 24, so that the blow-by prevention unit 30 is configured.

  Here, the adsorbent 24 is set so as to have a higher ability to adsorb evaporated fuel as compared to the adsorbent 28. Further, the adsorbent 28 is set to have a higher ability to release the adsorbed evaporated fuel than the adsorbent 24. Further, the adsorbent 28 is set so that the resistance (airflow resistance) when the gas passes is equal to or smaller than that of the adsorbent 24.

  In addition, between the other end wall 14 </ b> B and the filter film 18 </ b> B is a communication portion 32 that communicates the ORVR canister portion 26 and the blow-through prevention portion 30.

  The second housing 16 is filled with an adsorbent 34 made of activated carbon in the form of particles or pellets that is substantially the same as the ORVR canister 26, for example, and forms an evaporation / ORVR canister 36.

  One end wall 14A of the first housing 14 and one end wall 16A of the second housing 16 are provided with evaporative fuel introduction ports 44 and 46 at positions corresponding to the ORVR canister portion 26 and the evaporation / ORVR canister portion 36, respectively. ing. An evaporated fuel introduction pipe 48 communicating with a fuel tank (not shown) is branched and connected to the evaporated fuel introduction ports 44 and 46, respectively. A vapor switching valve 50 is provided between the branched portion of the evaporated fuel introduction pipe 48 and the evaporated fuel introduction port 44. The evaporated fuel generated in the fuel tank is sent to both the ORVR canister unit 26 and the evaporator / ORVR canister unit 36 by opening the vapor switching valve 50. However, when the vapor switching valve 50 is closed, only the evaporator / ORVR canister unit 36 is sent. To be sent to.

  Also, the one end wall 14A of the first housing 14 is provided with an atmosphere communication port 52 corresponding to the blow-off prevention unit 30, and an atmosphere communication pipe 54 is connected to open the atmosphere.

  A communication pipe 56 is provided between the other end wall 16 </ b> B of the second housing 16 and the other end wall 14 </ b> B of the first housing 14, and the inside communicates with the evaporation / ORVR canister unit 36 and the blow-off prevention unit 30. It is set as the communication part 58 to do. The communicating portion 58 is provided with a variable orifice 38. The variable orifice 38 allows gas to move between the evaporation / ORVR canister unit 36 and the blow-through prevention unit 30 when the valve is opened. However, when the valve is closed, the variable orifice 38 functions as an orifice having a smaller opening cross section than when the valve is opened. The movement of the gas between the canister part 36 and the blow-through prevention part 30 is limited so as to be less than when the valve is opened.

  Discharge ports 40A and 40B are provided from one end wall 14A of the first housing 14 and the other end wall 16A of the second housing 16, and purge discharge pipes 42A and 42B are connected to the respective ports. The purge discharge pipes 42A and 42B are purge discharge passages 60A and 60B, which are joined together to form a single purge discharge pipe 42, leading to an unillustrated engine air supply system. .

  A purge switching valve 62 is provided at the joining point of the purge discharge pipes 42A and 42B, and either one or both of the ORVR canister unit 26 and the evaporation / ORVR canister unit 36 are selected and supplied to one purge discharge pipe 42. And evaporative fuel is sent.

  The vapor switching valve 50, the purge switching valve 62, and the variable orifice 38 are controlled by a control circuit (not shown) based on, for example, information sent from a refueling sensor that detects when a fuel tank is refueled. .

  Next, the operation of this embodiment will be described.

  When fuel is supplied to the fuel tank, the vapor switching valve 50 is opened by a control circuit (not shown), and the variable orifice 38 is also opened. Since the ventilation resistance of the adsorbent 34 is reduced by opening the variable orifice 38, a large amount of evaporated fuel generated during refueling can be adsorbed by the adsorbent 34 of the evaporator / ORVR canister 36. Then, the evaporated fuel at the time of refueling is sent to both the ORVR canister unit 26 and the evaporation / ORVR canister unit 36 by the vapor switching valve 50, and the evaporated fuel is adsorbed by the adsorbents 24 and 34. As described above, in the present embodiment, since the evaporated fuel at the time of refueling can be adsorbed by the evaporation / ORVR canister unit 36 as well, the ORVR canister unit 26 can be downsized as compared with the configuration in which the ORVR canister unit 26 adsorbs only. However, the adsorption performance required at the time of refueling can be secured. That is, it is possible to reduce the overall size while ensuring the necessary adsorption performance for the evaporated fuel generated during refueling.

  In contrast, during operation, the vapor switching valve 50 is closed and the variable orifice 38 is also closed by a control circuit (not shown). As a result, the evaporated fuel generated in the fuel tank is not sent to the ORVR canister unit 26 but is sent only to the evaporation / ORVR canister unit 36. Since the ventilation resistance of the communication portion 58 is increased by closing the variable orifice 38, the vaporized fuel and adsorbent can be prevented from being blown out due to the low ventilation resistance of the evaporator / ORVR canister portion 36 itself. The contact time with 34 can be lengthened. That is, even if the adsorbent 34 of the evaporator / ORVR canister unit 36 has a ventilation resistance comparable to that of the adsorbent 24 of the ORVR canister unit 26, the evaporated / operated canister unit 36 efficiently uses the evaporated fuel during operation. Can be adsorbed.

  Further, the evaporated fuel communicates with the blow-off prevention unit 30 through the communication unit 58 and is adsorbed by the adsorber 28 as in the case of refueling.

  As can be seen from the above description, in this embodiment, the adsorbent 24 (activated carbon) of the ORVR canister unit 26 is set to have a small airflow resistance in accordance with the treatment of the evaporated fuel generated in large quantities during refueling. In addition, for the adsorbent 24 (active body) of the evaporator / ORVR canister 36, even if the ventilation resistance of itself is reduced, by increasing the ventilation resistance by the variable orifice 38, it is possible to suppress the escape of the evaporated fuel, Adsorption performance can be secured by extending the contact time with the evaporated fuel generated during operation. In addition, since the ventilation resistance of the adsorbent 34 (activated carbon) of the evaporation / ORVR canister 36 is reduced, the variable orifice 38 reduces the ventilation resistance to cope with the treatment of evaporated fuel generated in large quantities during refueling. become able to. Thus, by reducing the ventilation resistance of the adsorbents 24 and 34 for both the ORVR canister unit 26 and the evaporation / ORVR canister unit 36, both of them can be used for adsorbing the evaporated fuel during refueling. Compared with a configuration in which only the ORVR canister unit 26 is used for adsorbing the evaporated fuel during refueling, the ORVR canister unit 26 can be reduced in size while maintaining the processing capability of the evaporated fuel. However, downsizing can be achieved.

  In order to achieve the above effect, the airflow resistance of the adsorbents 24 and 34 is preferably 0.5 to 1.5 kPa (air flow rate 70 L / min). That is, by setting the airflow resistance to 1.5 kPa or less, it becomes possible to reliably adsorb evaporated fuel generated in large quantities during refueling. However, if the ventilation resistance is too small, more adsorbents are required to reliably adsorb the evaporated fuel. Therefore, from the viewpoint of reliably adsorbing the evaporated fuel with a small number of adsorbents, the ventilation resistance is preferably 0.5 kPa or more.

  At the time of purging, the air blow-in prevention unit 30 is purged by the air flowing in through the atmosphere communication pipe 54, but it is also necessary to purge the ORVR canister unit 26 and the evaporation / ORVR canister unit 36. In particular, the ORVR canister unit 26 only needs to be purged from one refueling to the next refueling. However, the evaporative fuel is always adsorbed to the evaporator / ORVR canister unit 36 during operation. It is necessary to appropriately control the purge distribution, such as performing the purge of the ORVR canister unit 36 with priority. In the present embodiment, the purge switching valve 62 and the variable orifice 38 enable appropriate purge distribution.

  Further, after purging or the like (for example, when the vehicle is stopped), the evaporated fuel may try to diffuse from the ORVR canister unit 26 or the evaporation / ORVR canister unit 36. The release of fuel into the atmosphere is also prevented. This also increases the processing capability of the evaporated fuel in the evaporated fuel processing device 12.

  In addition, in the present embodiment, the blow-by prevention unit 30 is provided in common to both the ORVR canister unit 26 and the evaporation / ORVR canister unit 36. Therefore, the number of parts can be reduced and the space efficiency can be improved as compared with the configuration in which such a blow-off prevention unit is provided separately for each of the ORVR canister unit 26 and the evaporation / ORVR canister unit 36. .

  FIG. 2 shows a fuel vapor processing apparatus 82 according to the second embodiment of the present invention. In the second embodiment, the same components and members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the second embodiment, unlike the first embodiment, a filter film 85A parallel to the one end wall 84A and a filter film 85B parallel to the other end wall 84B are provided in one housing 84. Further, in the housing 84, two partition walls 87 and 89 that are perpendicular to the filter films 85A and 85B and parallel to each other are provided. The filter films 85A and 85B and the partition walls 87 and 89 constitute the blow-off prevention unit 30, the evaporation / ORVR canister unit 36, and the ORVR canister unit 26 in the housing 84, and these are integrally modularized. . In particular, in the second embodiment, the evaporation / ORVR canister 36 is disposed adjacent to the blow-by prevention unit 30.

  In the second embodiment, as described above, the evaporation / ORVR canister unit 36 is disposed adjacent to the blow-through prevention unit 30, and the return of the evaporated fuel from the blow-through prevention unit 30 to the ORVR canister unit 26 is more effectively performed. Can be prevented.

  Further, in the second embodiment, the blow-by prevention unit 30, the evaporation / ORVR canister unit 36, and the ORVR canister unit 26 are integrated into a module, so that, for example, the configuration is smaller than that of the first embodiment. Can do. Conversely, in the configuration having two housings as in the first embodiment, the arrangement of each housing can be arranged at a desired position, and as a result, the degree of freedom in arrangement can be increased as compared with the second embodiment. Become.

  FIG. 3 shows a fuel vapor processing apparatus 92 according to the third embodiment of the present invention. In the second embodiment, the same components and members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the third embodiment, a purge block valve 94 is provided in place of the purge switching valve 62 of the first embodiment. The purge block valve 94 is disposed not in the merged portion of the purge discharge pipes 42A and 42B but in the purge discharge pipe 42A between the ORVR canister portion 26 and the merged portion. If the purge block valve 94 is opened, the ORVR canister section 26 can be purged, but if the valve is closed, the ORVR canister section 26 is not purged.

  In the third embodiment, a purge opening / closing valve 96 is provided in the purge discharge pipe 42 from the merged portion of the purge discharge pipes 42A and 42B to the air supply system of the engine (not shown). By opening the purge opening / closing valve 96, it is possible to purge both the ORVR canister section 26 and the evaporation / ORVR canister section 36. By closing the valve, both of them are not purged.

  Note that the vapor switching valve 50, the variable orifice 38, the purge block valve 94, and the purge on / off valve 96 are based on information sent from, for example, a refueling sensor that detects when a fuel tank is refueled, as in the first embodiment. It is controlled by a control circuit (not shown).

  In the third embodiment having such a configuration, the variable orifice 38, the purge block valve 94, and the purge on / off valve 96 are interlocked and controlled by a control circuit (not shown), so that the ORVR canister unit 26 and the evaporation / ORVR canister unit 36 are controlled. Appropriate purge distribution control can be performed. For example, when purging the evaporator / ORVR canister unit 36 with priority, the variable orifice 38 and the purge open / close valve 96 may be opened, and the purge block valve 94 may be closed. When purging both the ORVR canister unit 26 and the evaporation / ORVR canister unit 36, the purge block valve 94 may be opened in addition to the variable orifice 38 and the purge opening / closing valve 96. Further, control in accordance with opening / closing of a purge amount control valve provided in the vicinity of an air supply system of an engine (not shown) is also possible.

It is sectional drawing which shows schematic structure of the evaporative fuel processing apparatus of 1st embodiment of this invention. It is sectional drawing which shows schematic structure of the evaporative fuel processing apparatus of 2nd embodiment of this invention. It is sectional drawing which shows schematic structure of the evaporative fuel processing apparatus of 3rd embodiment of this invention.

Explanation of symbols

12 Evaporative fuel treatment device 14 First housing 14A One end wall 14B Other end wall 16 Second housing 16A One end wall 16B Other end walls 18A, 18B Filter membranes 20A, 20B Filter membranes 22 Partition walls 24 Adsorbent (activated carbon)
26 ORVR canister (canister for refueling)
28 Adsorbent 30 Blow-off prevention part 32 Communication part 34 Adsorbent (activated carbon)
36 Evaporator / ORVR canister (canister for operation)
38 Variable orifice (Ventilation resistance variable means)
40A, 40B Discharge port 42, 42A, 42B Purge discharge pipe 44, 46 Evaporated fuel introduction port 48 Evaporated fuel introduction pipe 50 Vapor switching valve 52 Atmospheric communication port 54 Atmospheric communication pipe 56 Communication pipe 58 Communication section (communication means)
60A, 60B Purge discharge passage 62 Purge switching valve 82 Evaporated fuel processing device 84 Housing 84A One end wall 84B Other end wall 85A Filter membrane 85B Filter membrane 87 Partition 89 Partition 92 Evaporated fuel processing device 94 Purge seal valve 96 Purge open / close valve

Claims (2)

A canister for refueling in which the evaporated fuel generated in the fuel tank during refueling is adsorbed by activated carbon;
The evaporative fuel generated in the fuel tank is activated carbon when the fuel tank is refueled and the fuel tank is refueled and when the fuel tank is not refueled. A canister for operation that is adsorbed by
A blow-off prevention unit that is provided corresponding to the operation canister unit and prevents the vaporized fuel from blowing through from the operation canister unit to the atmosphere, and
Communicating means for communicating the canister unit for operation and the blow-through preventing unit;
A communicating portion that communicates the canister portion for refueling and the blow-through preventing portion;
Ventilation resistance variable means for changing the ventilation resistance of the communication means, reducing the ventilation resistance of the communication means during the refueling , and increasing the ventilation resistance of the communication means during the operation ,
The evaporative fuel generated in the fuel tank is opened during the refueling and is sent to the refueling canister unit and the operating canister unit, and the evaporative fuel is refueled by being closed during the operation. A vapor switching valve that is not sent to the hour canister but only to the running canister,
The evaporative fuel processing apparatus characterized by having. The evaporated fuel processing apparatus according to claim 1 , wherein the operation-time canister unit and the blow-by prevention unit are disposed adjacent to each other.

Images