JP2006138247A - Fuel vapor discharge-preventing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel vapor discharge-preventing system capable of preventing the unnecessary operation of an auto-stop mechanism before reaching a full tank in filling fuel by reducing ventilation resistance during fueling, and preventing overfilling of fuel. <P>SOLUTION: A pump module 46 comprising a vacuum pump 50 and a blocking valve 52 is provided at an atmosphere side port of a canister 32, and when an ECM 54 determines the start of fueling by a detection signal of a fueling determining switch 26, the blocking valve 52 is opened, and the vacuum pump 50 is operated to lead negative pressure into a fuel tank 16. Ventilation resistance is thereby reduced to suppress the liquid level rise of a feed pipe 18 to thereby prevent unnecessary operation of auto-stop. Further, when a full tank detecting valve 38 is closed to detect a full tank state, the blocking valve 52 is closed, so that overfilling of fuel 14 can also be prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention includes a canister that adsorbs a fuel component contained in fuel vapor, a first line that sends fuel vapor generated in the fuel tank to the canister, and a second line that releases air after passing through the canister to the atmosphere. The present invention relates to an improved fuel vapor emission prevention system.

Generally, in gasoline vehicles, fuel vapor is generated from a fuel tank and a carburetor because gasoline is highly volatile. For this reason, a fuel vapor discharge prevention system is mounted for the purpose of preventing the fuel vapor from being discharged into the atmosphere as it is. The canister constitutes the main part of the fuel vapor emission prevention system. The canister is filled with activated carbon or the like, and by introducing the fuel vapor generated in the fuel tank or the like, the fuel component contained in the fuel vapor is prevented from being adsorbed by the activated carbon and discharged into the atmosphere. It has become.
JP-A-7-293366 JP 2001-206081 A

  However, the canister generally tends to have a ventilation resistance, and therefore, the ventilation resistance is larger than the fuel flow at the time of refueling in a refueling nozzle having a low injection input or a vehicle having a low refueling port position with respect to the fuel tank. In such a case, the liquid level rises in the fuel inlet pipe, and the auto-stop mechanism provided in the fuel supply nozzle may operate before the fuel tank reaches a full tank. Therefore, the operator has to repeat the refueling operation until the fuel tank is full.

  Further, if the refueling operation is continued for a long time even after the fuel tank is full, the fuel will be refueled beyond the preset full tank position. In that case, the cut-off valve is closed by the fuel and the pressure relief path is shut off, making it impossible to control the pressure in the fuel tank, or the fuel leaks from the fuel tank to the canister when the vehicle is running, etc. There is a possibility that a problem such as a decrease in the adsorption performance of a certain activated carbon may occur.

  In consideration of the above facts, the present invention can reduce the airflow resistance during refueling to prevent unnecessary operation of the auto-stop mechanism before the fuel tank is full, and fuel can be over-injected. It is an object to obtain a fuel vapor discharge prevention system that can prevent the above.

  A fuel vapor discharge prevention system according to a first aspect of the present invention includes a canister that adsorbs a fuel component contained in fuel vapor, a first end opened in the fuel tank, and the other end communicated with the canister. A first line for sending fuel vapor generated in the tank to the canister, and a second line in which one end is communicated with the canister and the other end is opened to the atmosphere, and the air after passing through the canister is released into the atmosphere. A fuel vapor discharge prevention system configured to include a negative pressure pump that is provided in the second line and operates to apply a negative pressure to the canister, and a refueling start / end detection that detects a refueling start and a refueling end Means, an internal pressure detecting means for detecting the internal pressure of the oil tank, and an oil supply start state detected by the oil supply start / end detecting means, the negative pressure pump is operated, When it is detected refueling end state by or if refueling start end detecting means full condition is detected by the pressure detecting means it is characterized by comprising a control means for stopping the operation of the suction pump, the.

  A fuel vapor discharge prevention system according to a second aspect of the present invention is the fuel vapor discharge prevention system according to the first aspect of the present invention, wherein the second line can be opened and closed between the canister and the negative pressure pump in the second line. A line open / close valve is provided, and the control means opens the second line open / close valve when the oil supply start / end detection means detects the oil supply start / end detection means, and the internal pressure detection means detects the full tank state. In this case, the second line on / off valve is closed, and when the end of refueling is detected by the refueling start / end detecting means, the second line on / off valve is opened again.

  According to the first aspect of the present invention, when the refueling start state is detected by the refueling start / end detecting means, the negative pressure pump provided in the second line is operated by the control means. For this reason, a negative pressure is introduced into the canister and the first line connecting the canister and the fuel tank. Accordingly, the ventilation resistance during refueling is reduced, and the fuel vapor generated in the fuel tank flows smoothly into the canister through the first line, and the fuel component in the fuel vapor is adsorbed and removed by the canister. Thereby, it is possible to prevent the liquid level from rising in the fuel supply pipe, and before the fuel tank becomes full, the auto-stop mechanism provided in the fuel supply nozzle operates and becomes unnecessary (that is, It is possible to avoid refueling stoppage (unless it is unnecessary).

  When the full pressure state is detected by the internal pressure detecting means or when the refueling end state is detected by the refueling start end means, the operation of the negative pressure pump is stopped by the control means. Therefore, no negative pressure is introduced thereafter.

  According to the second aspect of the present invention, the second line provided between the canister and the negative pressure pump in the second line by the control means when the oil supply start / end detection means is detected by the control means. The on-off valve is opened. Therefore, the negative pressure of the negative pressure pump can be introduced into the fuel tank. Thereafter, when the full pressure state is detected by the internal pressure detecting means, the second line on-off valve is closed. For this reason, even if an attempt is made to inject more fuel into the fuel tank, the second line through which the fuel vapor escapes is blocked, so that the liquid level in the oil supply pipe rises and additional fuel cannot be supplied. Further, when the refueling end state is detected by the refueling start / end detecting means, the second line on-off valve is opened again by the control means. For this reason, ventilation with the air | atmosphere via a 2nd line is attained.

  A fuel vapor discharge prevention system according to a first aspect of the present invention includes a canister that adsorbs a fuel component contained in fuel vapor, a first end opened in the fuel tank, and the other end communicated with the canister. A first line for sending fuel vapor generated in the tank to the canister, and a second line in which one end is communicated with the canister and the other end is opened to the atmosphere, and the air after passing through the canister is released into the atmosphere. In the fuel vapor discharge prevention system configured to include, a negative pressure pump that is provided in the second line and operates to apply a negative pressure to the canister, and a refueling start / end detecting unit that detects a refueling start and a refueling end, When the oil supply start state is detected by the internal pressure detection means for detecting the internal pressure of the oil supply tank and the oil supply start / end detection means, the negative pressure pump is operated to And a control means for stopping the operation of the negative pressure pump when a full tank state is detected by the discharge means or when an oil supply end state is detected by the oil supply start / end detection means. It has an excellent effect that it is possible to prevent unnecessary operation of the auto-stop mechanism before it reaches a full tank during fuel injection.

  A fuel vapor discharge prevention system according to a second aspect of the present invention is the fuel vapor discharge prevention system according to the first aspect, wherein the second line on-off valve is capable of opening and closing the second line between the canister and the negative pressure pump in the second line. And the control means opens the second line on / off valve when the oil supply start / end detection means detects the oil supply start / end condition, and the control means opens the second line when the internal pressure detection means detects the full tank condition. Since the on-off valve is closed and the end of refueling is detected by the refueling start / end detecting means, the second line on / off valve is opened again, so that it is possible to prevent excessive fuel injection. It has the effect.

  Hereinafter, an embodiment of a fuel vapor discharge prevention system according to the present invention will be described with reference to FIGS.

  FIG. 1 shows an overall configuration diagram of a fuel system 12 including a fuel vapor emission prevention system 10 according to the present embodiment. As shown in this figure, the fuel system 12 includes a box-shaped fuel tank 16 that stores fuel 14. One end of a fuel supply pipe 18 is opened in a penetrating state on the upper side surface of the fuel tank 16. The other end of the oil supply pipe 18 is disposed at a position facing the fuel lid 22 disposed at a predetermined position on the side of the vehicle body with the cap 20 attached. The oil supply pipe 18 is provided with a circulation line 24 along the same.

  On the hinge side of the fuel lid 22, a fuel supply determination switch 26 is disposed as a fuel supply start / end detection means for detecting the open / closed state of the fuel lid 22. In the present embodiment, the fuel supply determination switch 26 that detects the open / closed state of the fuel lid 22 is used as the fuel supply start / end detection means. However, the present invention is not limited to this. A sensor for detecting whether or not the fuel supply start / end may be provided, or a sensor for detecting whether or not a fuel supply nozzle has been inserted into the fuel supply pipe 18 may be provided as the fuel supply start / end detection means. Any sensor and switches that can detect the end of refueling can be applied.

  A pressure sensor 28 as an internal pressure detecting means for detecting the internal pressure in the fuel tank 16 is disposed at a predetermined position on the upper end surface of the fuel tank 16. The pressure sensor 28 serves to monitor the internal pressure of the fuel tank 16 by always outputting the pressure fluctuation in the fuel tank 16 to the ECM 54 described later.

  Further, a fuel pump module 30 for supplying the fuel 14 to the engine is disposed in the fuel system 12.

  Further, the fuel system 12 includes a canister 32 that forms the main part of the fuel vapor emission prevention system 10. The canister 32 is adapted to adsorb and remove the fuel component contained in the fuel vapor by the activated carbon 34. The canister 32 and the fuel tank 16 are communicated with each other by a vent line 36 as a first line. One end of the vent line 36 communicates with the lower side of the canister 32. The other end of the vent line 36 is disposed in an open state above the inside of the fuel tank 16, and a full tank detection valve (ORVR valve) 38 and a cut-off valve 40 as internal pressure detecting means are provided at the end. It is attached. The full tank detection valve 38 is disposed at a position lower than the cutoff valve 40, and the valve (float valve) is closed when the tank is full.

  In addition, one end of a fresh air line 42 as a second line is communicated with the upper portion of the canister 32. An air filter 44 is disposed in the middle of the fresh air line 42. Furthermore, the other end side of the fresh air line 42 is open to the atmosphere.

  A pump module 46 is disposed between the canister 32 and the air filter 44 in the fresh air line 42 described above (that is, on the air port side of the canister 32). The pump module 46 is provided with a casing 48, a negative pressure pump 50 disposed in the casing 48, an upstream side (canister 32 side) of the negative pressure pump 50, and can open and close the atmospheric port of the canister 32. And a block valve 52 as a second line opening / closing valve provided. The blocking valve 52 is composed of an electromagnetic valve. Note that a pressure sensor may be provided in the pump module 46 and used for controlling the operation of the negative pressure pump 50.

  Further, the fuel vapor discharge prevention system 10 includes an ECM 54 as a control means. The ECM 54 is connected to various sensors and switches (a fuel supply determination switch 26, a full tank detection valve 38, a pressure sensor 28, a cut-off valve 40, a fuel lid opener switch 56, etc.), and outputs each detection signal to the ECM. 1, the signal lines of some of these elements are not shown, and a negative pressure pump 50 and a sealing valve 52 to be controlled are connected to the ECM 54. The operation control of the negative pressure pump 50 and the opening / closing control of the blocking valve 52 are performed based on the detection signal.

(Operation and effect of this embodiment)
Next, the operation and effect of the present embodiment will be described with reference to FIG.

  FIG. 2 is a graph showing changes in the tank pressure of the fuel tank 16 over time.

  When refueling, the driver first operates the fuel lid opener switch 56 so that the operator can open the fuel lid 22. Next, the operator opens the fuel lid 22, removes the cap 20 attached to the other end of the fuel supply pipe 18, inserts a fuel supply nozzle (not shown) into the fuel supply pipe 18, and fuel is injected.

  Here, in this embodiment, when refueling is started, the refueling determination switch 26 detects the refueling start state. In other words, in this embodiment, as an example, a configuration is adopted in which the ECM 54 determines that refueling is started by detecting an ON signal of the open / closed state of the fuel lid 22 using the fuel refueling determination switch 26.

  When the refueling start detection signal is input to the ECM 54 and it is determined that refueling is started, the ECM 54 opens the block valve 52 of the pump module 46 (against the biasing force) and operates the negative pressure pump 50 (see FIG. 2 A part). When the negative pressure pump 50 is activated, negative pressure is introduced from the canister 32 into the fuel tank 16 through the vent line 36. For this reason, the internal pressure of the fuel tank 16 decreases from the initial value (atmospheric pressure) following a predetermined broken line gradient. Further, the introduction of the negative pressure reduces the ventilation resistance during refueling along the path from the canister 32 to the fuel tank 16 via the vent line 36.

  When this state is reached, the actual refueling operation is started (see part B in FIG. 2). At this time, the fuel vapor generated in the fuel tank 16 during refueling flows smoothly into the canister 32 through the vent line 36, and the fuel component in the fuel vapor is adsorbed and removed by the activated carbon 34 filled in the canister 32. (Once it is adsorbed and held, air is introduced into the canister 32 using the negative pressure of the intake system during engine operation, the fuel component (gasoline component) adsorbed on the activated carbon is released and sent to the intake system to regenerate the activated carbon. )

  Accordingly, it is possible to prevent the liquid level from rising in the fuel supply pipe 18, and before the fuel tank 16 becomes full, the auto-stop mechanism provided in the fuel supply nozzle is activated and becomes unnecessary (that is, It is possible to avoid refueling stoppage (unless it is unnecessary). As a result, according to the present embodiment, even if the vehicle is difficult to lubricate, the possibility of an automatic stop before full tank is greatly reduced, and the lubrication work is facilitated.

  The fuel vapor from which the fuel component has been removed is released to the atmosphere through the fresh air line 42.

  On the other hand, when the fuel tank 16 is full, the full tank detection valve (ORVR valve) 38 is closed. When the full tank detection valve 38 is closed, the internal pressure of the fuel tank 16 suddenly increases thereafter (see part C in FIG. 2). Since the internal pressure of the fuel tank 16 is monitored by the pressure sensor 28, when a sudden pressure increase occurs due to the closing of the full tank detection valve 38, it is determined by the ECM 54 that the tank is instantaneously full. When the full tank state is detected in this way, the closing valve 52 is closed by the ECM 54 and the operation of the negative pressure pump 50 is stopped.

  Therefore, even if an attempt is made to inject more fuel 14 into the fuel tank 16, the fresh air line 42 through which the fuel vapor escapes is blocked, so that the liquid level in the fuel supply pipe 18 rises and additional fuel can not be supplied. Disappear.

  Thereafter, when the refueling operation is completed and the fuel lid 22 is closed, the refueling determination switch 26 is turned off, and the ECM 54 determines that refueling is completed (see D part in FIG. 2). When it is determined that refueling is finished, the ECM 54 opens the blocking valve 52 again. For this reason, ventilation with the atmosphere via the fresh air line 42 becomes possible again.

  As described above, according to the fuel vapor discharge prevention system 10 according to the present embodiment, it is possible to reduce the airflow resistance during refueling and prevent the operation of the unnecessary auto stop mechanism before reaching the full tank at the time of fuel injection, Furthermore, over-injection of fuel can be prevented.

  FIG. 3 is a graph showing changes in the tank internal pressure when only the operation of the negative pressure pump 50 is operated by removing the influence of the opening and closing of the blocking valve 52 from FIG. 2, and the invention according to claim 1 The characteristic corresponding to is illustrated.

(Supplementary explanation of this embodiment)
In the fuel vapor discharge prevention system 10 according to this embodiment described above, the negative pressure pump 50 is exclusively installed in the pump module 46. However, the present invention is not limited to this, and it is used to detect the drilling of the fuel system 12. A negative pressure pump may be used.

  Further, in the fuel vapor discharge prevention system 10 according to the above-described embodiment, the function of the fuel supply start / end detection unit is provided in the fuel supply determination switch 26. However, the present invention is not limited thereto, and the fuel supply start detection unit and the fuel supply end detection unit are included. And may be set separately.

  Furthermore, in the fuel vapor discharge prevention system 10 according to the above-described embodiment, a configuration is adopted in which the negative pressure pump 50 is stopped when a full tank state is detected by the full tank detection valve 38 and the pressure sensor 28. However, the negative pressure pump may be stopped when the refueling end state is detected by the refueling start / end detecting means (or the refueling end detecting means provided independently).

1 is an overall configuration diagram of a fuel system configured to include a fuel vapor emission prevention system according to the present embodiment. It is the graph which showed the relationship between the elapsed time at the time of using the fuel vapor discharge | emission prevention system which concerns on this embodiment, and the tank internal pressure of a fuel tank. It is the graph (what remove | eliminated the influence of the sealing valve from FIG. 2) which showed the relationship between the elapsed time at the time of using the fuel vapor discharge | emission prevention system which concerns on this embodiment, and the pressure in a fuel tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel vapor discharge | emission prevention system 14 Fuel 16 Fuel tank 26 Refueling determination switch (fueling start end detection means)
28 Pressure sensor (internal pressure detection means)
32 Canister 36 Vent line (first line)
38 Full tank detection valve (internal pressure detection means)
42 Fresh air line (second line)
50 Negative pressure pump 52 Blocking valve (second line on-off valve)
54 ECM (control means)

Claims (2)

A canister that adsorbs fuel components contained in the fuel vapor;
A first line having one end opened in the fuel tank and the other end communicated with the canister, and sends fuel vapor generated in the fuel tank to the canister;
A second line in which one end is communicated with the canister and the other end is opened to the atmosphere, and air after passing through the canister is released into the atmosphere;
A fuel vapor emission prevention system comprising:
A negative pressure pump that is provided in the second line and operates to apply a negative pressure to the canister;
Refueling start / end detecting means for detecting refueling start and refueling end;
An internal pressure detecting means for detecting an internal pressure of the oil tank;
When the refueling start / end detecting means detects the refueling start state, the negative pressure pump is operated, and the internal pressure detecting means detects the full tank state or the refueling start / end detecting means detects the refueling end state Control means for stopping the operation of the negative pressure pump,
A fuel vapor discharge prevention system comprising: Between the canister and the negative pressure pump in the second line, a second line on-off valve capable of opening and closing the second line is provided,
The control means opens the second line on / off valve when the oil supply start / end detection means detects the oil supply start / end condition, and the control means opens the second line when the internal pressure detection means detects the full tank condition. Closing the on-off valve and reopening the second line on-off valve when the end of refueling is detected by the refueling start / end detecting means;
The fuel vapor discharge prevention system according to claim 1.

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