JP2009108710A - Evaporated fuel treating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an evaporated fuel treating device capable of liquefying evaporated fuel generated inside a fuel tank and effectively using the liquefied fuel for combustion in an engine. <P>SOLUTION: A condenser 30 for cooling and condensing (liquefying) evaporated fuel is arranged between the fuel tank 18 and a canister 16. Return piping for returning liquefied fuel from the condenser 30 to the fuel tank 18 is arranged so that the lower end of the piping faces inside of a suction filter 26. By directly sending fuel evaporated once and then liquefied to the engine, the fuel can be effectively used for combustion in the engine. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel vapor processing apparatus.

  In general, evaporative fuel generated in a fuel tank or the like is processed by a canister. However, in Patent Document 1, a cooler that cools fuel vapor is disposed between the fuel tank and the canister, and is liquefied by the cooler. An evaporative fuel processing device is described in which the fuel is returned to the fuel tank. Thus, by evaporating the evaporated fuel, the adsorption load of the canister can be reduced, and the evaporated fuel can be processed efficiently.

By the way, in the configuration described in Patent Document 1, the liquefied fuel is simply returned to the fuel tank through the recovery passage. Actually, it is desirable to effectively use the fuel liquefied after once vaporized in this way as fuel for the engine.
JP 2002-285919 A

  An object of the present invention is to obtain an evaporative fuel processing apparatus that can liquefy evaporative fuel generated in a fuel tank and can effectively use the liquefied fuel for combustion in an engine in consideration of the above facts.

  In the first aspect of the present invention, a fuel tank in which fuel is stored, a delivery pipe that sends fuel to the engine from an opening that is opened in the fuel tank, and a fuel that is provided in an opening of the delivery pipe from the fuel tank A suction filter that removes foreign matters when the fuel is sent to the outside, a canister that contains activated carbon on which evaporated fuel generated in the fuel tank is adsorbed, a vapor pipe that sends evaporated fuel from the fuel tank to the canister, It has a condensing means provided in the vapor pipe to condense the evaporated fuel into liquefied fuel, and a return pipe for returning the liquefied fuel produced by the condensing means to the vicinity of the suction filter.

  In this evaporative fuel processing device, the fuel first passes through the suction filter to remove foreign matter, and then is sent to the engine through the delivery pipe.

  In addition, since this fuel vapor processing apparatus has a canister, it is possible to adsorb the fuel vapor generated in the fuel tank with activated carbon in the canister, but the vapor pipe is provided with a condensing means. Therefore, by this condensing means, the evaporated fuel is condensed into liquefied fuel. As a result, the amount of evaporated fuel sent to the canister is reduced, and the adsorption load of the canister can be reduced. Hereinafter, when simply referred to as “liquefied fuel”, the evaporated fuel is condensed and condensed by the condensing means.

  The liquefied fuel generated by the condensing means is returned to the vicinity of the suction filter in the fuel tank by the return pipe. Since the suction filter is provided at the opening of the delivery pipe, the liquefied fuel is sent from the delivery pipe to the engine and burned. That is, the liquefied fuel can be actively sent to the engine and effectively used as the fuel.

  Note that the “near” here may be any extent as long as the liquefied fuel can be sent from the delivery pipe to the engine as described above. In general, since the suction filter is often formed in a closed curved surface so as to surround the opening of the delivery pipe, the end of the return pipe may be disposed so as to directly face the suction filter.

  According to a second aspect of the present invention, in the first aspect of the present invention, the condensing unit includes a liquid reservoir that stores the condensed liquefied fuel, and the return pipe connected to the liquid reservoir. It has a discharge port portion for discharging liquefied fuel to the return pipe, and a closing member provided in the discharge port portion and closing the discharge port portion when the liquefied fuel in the liquid reservoir portion decreases.

  Therefore, the liquefied fuel is stored in the liquid reservoir. This liquefied fuel is discharged from the discharge port and discharged to the return pipe.

  The discharge port portion is provided with a closing member, and the discharge port portion is closed when the liquefied fuel in the liquid reservoir is reduced. For this reason, the discharge of gas to the return pipe can be suppressed.

  According to a third aspect of the invention, there is provided the return pipe according to the first or second aspect of the invention, wherein the fuel is allowed to move from the condensing means into the fuel tank and moved in the reverse direction. And a check valve for blocking.

  Accordingly, the movement of the fuel (liquefied fuel) from the condensing means to the fuel tank is allowed, but the movement of the fuel (reverse flow) from the fuel tank to the condensing means can be prevented.

  Since the present invention has the above configuration, the evaporated fuel generated in the fuel tank can be liquefied, and the liquefied fuel can be effectively used for combustion in the engine.

  FIG. 1 shows a fuel vapor processing apparatus 12 according to a first embodiment of the present invention. As an example, the evaporative fuel processing device 12 is applied to a so-called plug-in hybrid vehicle that is charged from a household power source or the like, stored in a battery (not shown), and that power can be used for vehicle travel. Therefore, the vehicle has a power plug (not shown) to be plugged into a household outlet or a charging stand.

  The evaporative fuel processing device 12 has a canister 16 in which activated carbon is accommodated, and can evaporate the evaporated fuel stored in the fuel tank 18 with the activated carbon. Further, a fuel pump 20 is disposed in the fuel tank 18, and by driving the fuel pump 20, fuel can be sent (supplied) from the delivery pipe 22 to an engine (not shown).

  As shown in detail in FIG. 3, the delivery pipe 22 extends to the lower side of the fuel pump 20 and has a lower end serving as a fuel intake port 24, and a suction having a closed curved surface so as to surround the fuel intake port 24. A filter 26 is attached. Therefore, the fuel in the fuel tank 18 is supplied to the engine in a state where foreign matters are removed by the suction filter 26. Depending on the type of engine and fuel, for example, the fuel may be sent out due to, for example, negative pressure generated from the engine side. In this case, the delivery pipe 22 does not have the fuel pump 20 and the delivery pipe 22 is directly connected to the fuel tank 18. The lower end may be extended to the lower part and the lower end may be used as the fuel inlet 24.

  As shown in FIG. 1, the fuel tank 18 and the canister 16 are connected by a vapor pipe 28, and a condenser 30 is provided in the middle of the vapor pipe 28. As shown in detail in FIG. 2, the condenser 30 has a condenser body 32 formed in a substantially cylindrical shape, and a gas introduction port 34 and a gas discharge port 36 are formed on the upper base 32 </ b> U, A vapor pipe 28 is connected to each. Further, inside the condenser body 32, a partition wall 38 is extended downward from the upper bottom 32U so as to separate the gas introduction port 34 and the gas discharge port 36, but the partition wall 38 has a lower bottom 32L. The length of the partition wall 38 is lowered from the gas introduction port 34 to the left side of the drawing, wraps around the lower side of the partition wall 38, and then rises to the right side of the partition wall 38 to reach the gas discharge port 36. A gas flow path 40 is configured.

  One or a plurality of cooling fins 42 are arranged in the gas flow path 40. The cooling fins 42 have an action of cooling and condensing and evaporating the evaporated fuel flowing through the gas flow path 40 when supplied with electric power. In particular, in the present embodiment, for example, when a power plug (not shown) is connected to an external power source while the vehicle is parked, the power from the external power source is directly received and the cooling action by the cooling fins 42 can be exhibited.

  A portion below the partition wall 38 inside the condenser main body 32 is a liquid reservoir 44 in which liquid fuel generated by condensing evaporated fuel by the cooling fins 42 is stored. The lower bottom 32L of the condenser main body 32 has a circular liquefied fuel discharge port 46 formed at the center so that the liquefied fuel stored in the liquid reservoir 44 can be discharged. In particular, the upper surface of the lower bottom 32 </ b> L is a mortar-shaped inclined surface 48 that is gradually inclined from the periphery toward the liquefied fuel discharge port portion 46, so that the liquefied fuel easily flows into the liquefied fuel discharge port portion 46. The liquefied fuel discharge port 46 is positioned at the lowermost part of the liquid reservoir 44.

  A spherical float valve 50 having a specific gravity smaller than that of the liquefied fuel and a larger diameter than that of the liquefied fuel discharge port 46 is accommodated in the condenser main body 32. When a sufficient amount of liquefied fuel is present in the liquid reservoir 44 (the state shown in FIG. 2), the float valve 50 floats above the liquefied fuel discharge port 46, so the liquefied fuel discharge port 46. However, when the fuel in the liquid reservoir 44 decreases and the liquid level drops, the float valve 50 closes the liquefied fuel discharge port 46. In particular, the mortar-shaped inclined surface 48 guides the float valve 50 to the liquefied fuel discharge port 46 when the liquid level is lowered.

  The upper end of the return pipe 52 is connected to the liquefied fuel discharge port 46, that is, the lowermost part of the liquid reservoir 44. The return pipe 52 passes through the upper wall of the fuel tank 18, and the lower end thereof is located in the fuel tank 18.

  As shown in detail in FIG. 3, the lower end 52 </ b> L of the return pipe 52 is arranged and fixed as desired inside the suction filter 26. Therefore, the liquefied fuel returned into the fuel tank 18 by the return pipe 52 flows directly into the suction filter 26.

  As shown in FIG. 1, a check valve 54 is provided in the middle of the return pipe 52 so as to be positioned in the fuel tank 18. The check valve 54 is attached in such a direction as to allow the flow of fuel from the condenser 30 to the fuel tank 18 but prevent the flow in the opposite direction.

  An atmospheric communication pipe 56 is connected to the canister 16, and a block valve 58 is provided in the vicinity of the end of the atmospheric communication pipe 56. The atmospheric communication pipe 56 is provided with a pressure sensor 64 so that the pressure in the atmospheric communication pipe 56 can be detected. Since the atmosphere communication pipe 56 is also communicated with the canister 16, the detected pressure matches the pressure in the canister 16. The detected pressure data is sent to the ECU 60. The ECU 60 controls the condenser 30 (cooling fins 42) based on the pressure data.

  Further, a purge pipe 66 communicating with the engine is connected to the canister 16 so that a negative pressure acts on the canister 16 from the purge pipe 66 by driving the engine or the like. Due to this negative pressure, when the atmosphere is introduced from the atmosphere communication pipe 56, the evaporated fuel is desorbed and sent to the engine through the purge pipe 66.

  In the evaporated fuel processing apparatus 12 of the present embodiment, the ECU 60 includes a so-called OBD (On-Board Diagnostic) system, and performs a process for detecting a vehicle malfunction or the like under a predetermined condition. It has become. In particular, regarding the fuel tank 18, it is possible to detect the occurrence of a malfunction based on tank internal pressure data from a tank internal pressure sensor 62 provided in the fuel tank 18.

  Next, the operation of the evaporated fuel processing apparatus 12 of this embodiment will be described.

  In the evaporative fuel processing apparatus 12, the evaporative fuel generated in the fuel tank 18 is sent to the condenser 30 through the vapor pipe 28 and flows through the gas flow path 40. Here, when the ECU 60 operates the condenser 30, the evaporated fuel is condensed and liquefied by the cooling fins 42 and stored in the liquid reservoir 44. That is, since the evaporated fuel can be processed by the condenser 30 before being sent to the canister 16, the adsorption load of the canister 16 is reduced.

  In order to reduce the amount of evaporated fuel sent to the canister 16 in this way, for example, a configuration in which the entire fuel tank 18 is cooled is conceivable. In this case, however, the liquid fuel in the fuel tank 18 is also reduced. Since it cools, efficiency becomes worse. In the present embodiment, since only the evaporated fuel is cooled, it can be efficiently condensed.

  Moreover, the operation of the condenser 30 (energization to the cooling fins 42) can be performed from an external power source using a power plug (not shown). For this reason, exhaustion of the vehicle battery can be prevented. Of course, in a situation where there is no external power supply, power may be supplied from the battery of the vehicle.

  The operation of the condenser 30 can be performed according to the pressure value detected by the tank internal pressure sensor 62. That is, in the ECU 60, the condenser 30 may be operated so that the detection value of the pressure sensor 64 is equal to or less than a preset threshold value with the blocking valve 58 closed. Thus, by operating the condenser 30 when the pressure rises, the pressure resistance of the evaporated fuel processing device 12, particularly the canister 16, can be maintained high. At this time, if the blocking valve 58 is closed, inadvertent release of the evaporated fuel into the atmosphere can be suppressed.

  In addition, since the pressure in the atmospheric communication pipe 56, that is, the canister 16, is detected in a state where the blocking valve 58 is closed, more accurate pressure detection is possible as compared with the state in which the atmospheric communication pipe 56 is opened to the atmosphere.

  Further, for example, the closing valve 58 can be temporarily closed while the vehicle is running, and the internal pressure of the fuel tank 18 can be detected by the tank internal pressure sensor 62. Thereby, it is also possible to predict the generation rate of vaporized fuel (amount generated per unit time) without depending on the state of fuel (temperature, etc.). In this case, the operation of the condenser 30 may be controlled based on the predicted generation speed of the evaporated fuel. Even in this case, the amount of evaporated fuel flowing into the canister 16 can be suppressed by the operation of the condenser 30.

  In the present embodiment, as described above, the ECU 60 includes the OBD system. During the detection of the internal pressure of the fuel tank 18 by the OBD system, the operation of the condenser 30 is stopped, so that the influence of the operation of the condenser 30 on the change in the internal pressure of the fuel tank 18 is avoided and the fuel tank by the OBD is more accurately detected. 18 internal pressure detection can be executed.

  In the evaporated fuel processing apparatus 12 of this embodiment, the liquefied fuel generated by the condenser 30 is returned to the inside of the suction filter 26 through the return pipe 52. Since the suction filter 26 surrounds the fuel inlet 24, the returned liquefied fuel is sent directly to the engine and burned. That is, as compared with the configuration in which the liquefied fuel is returned to the outside of the suction filter 26 in the fuel tank 18, it can be more actively supplied to the engine and combusted.

  In particular, since the liquefied fuel is a fuel once evaporated into the fuel tank 18, there are many components having a low molecular weight, and when returned to the fuel tank 18, it is easily vaporized in a short time. By actively sending the liquefied fuel having many components that easily vaporize in this way to the engine, it is possible to suppress the evaporation (vaporization) of the fuel in the fuel tank 18 as a result. Moreover, by actively supplying the liquefied fuel to the engine in this way, the amount of fuel sent from the canister 16 to the engine by purging is also reduced.

  When the amount of liquefied fuel stored in the liquid reservoir 44 of the condenser 30 decreases and the liquid level drops, the float valve 50 closes the liquefied fuel discharge port 46. Therefore, it is possible to prevent the gas from being inadvertently returned to the suction filter 26 and to prevent the gas from flowing into the fuel pump 20 (so-called entrainment).

  The return pipe 52 is provided with a check valve 54. Therefore, for example, even when the liquid level fluctuates in the fuel tank 18, the reverse flow of the fuel, that is, the inflow to the condenser 30 can be prevented.

  In the above example, the return pipe 52 is disposed as desired inside the suction filter 26. Thereby, all of the liquefied fuel can be returned into the suction filter 26. However, it is not necessary to return all of the liquefied fuel into the suction filter 26, and only a part of the liquefied fuel may be returned into the suction filter 26. For example, even in a configuration in which the lower end 52L of the return pipe 52 is disposed in the vicinity of the suction filter 26 as in the modification of the present embodiment shown in FIG. If it flows into the suction filter 26, the liquefied fuel corresponding to the flow-in can be actively supplied to the engine and burned.

  In the above description, the condenser 30 is supplied with power using a power plug (not shown) provided in the plug-in hybrid vehicle. However, the present invention is also applicable to a vehicle that is not a plug-in hybrid vehicle, for example. In this case, a dedicated plug for supplying power to the condenser 30 may be provided.

It is the schematic which shows the structure of the evaporative fuel processing apparatus of one Embodiment of this invention. It is sectional drawing which shows the condenser which comprises the evaporative fuel processing apparatus of one Embodiment of this invention. It is the schematic which shows the suction filter which comprises the evaporative fuel processing apparatus of one Embodiment of this invention, and its vicinity. It is the schematic which shows the suction filter which comprises the evaporative fuel processing apparatus of the modification of one Embodiment of this invention, and its vicinity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Evaporated fuel processing apparatus 16 Canister 18 Fuel tank 20 Fuel pump 22 Delivery piping 24 Fuel inlet 26 Suction filter 28 Vapor piping 30 Condenser (condensing means)
38 Partition 40 Gas channel 42 Cooling fin 44 Liquid reservoir 46 Liquefied fuel outlet 50 Float valve (blocking member)
52 Return piping 54 Check valve (check valve)
56 Air communication pipe 58 Sealing valve 60 ECU
62 Tank internal pressure sensor 64 Pressure sensor 66 Purge piping

Claims (3)

A fuel tank in which fuel is stored;
A delivery pipe for delivering fuel to the engine from an opening opened in the fuel tank;
A suction filter provided at an opening portion of the delivery pipe for removing foreign matters when fuel is sent out from a fuel tank;
A canister containing activated carbon on which evaporated fuel generated in the fuel tank is adsorbed;
Vapor piping for sending evaporated fuel from the fuel tank to the canister;
Condensing means provided in the vapor piping to condense the evaporated fuel into liquefied fuel;
A return pipe for returning the liquefied fuel produced by the condensing means to the vicinity of the suction filter;
The evaporative fuel processing apparatus characterized by having. The condensing means;
A liquid reservoir for storing the condensed liquefied fuel;
An outlet for connecting the return pipe and discharging the liquefied fuel from the liquid reservoir to the return pipe;
A closing member that is provided in the discharge port portion and closes the discharge port portion when the liquefied fuel in the liquid reservoir portion decreases;
The evaporative fuel processing apparatus according to claim 1, comprising: A check valve that is provided in the return pipe and allows movement of fuel from the condensing means into the fuel tank and prevents movement in the reverse direction;
The evaporative fuel processing apparatus of Claim 1 or Claim 2 characterized by the above-mentioned.

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