JP4926159B2 - Evaporative fuel processing apparatus and purge method thereof - Google Patents

Description

  The present invention includes a first communication path for introducing evaporated fuel generated in a fuel tank that stores fuel, a canister connected to the first communication path and adsorbing the evaporated fuel, and intake air of the canister and an internal combustion engine An evaporative fuel processing apparatus comprising: a second communication path that communicates with the passage; and a purge processing unit that purges the evaporated fuel adsorbed by the canister to the internal combustion engine through the second communication path. About.

  A fuel tank is used to supply fuel to the internal combustion engine. In the fuel tank, vaporized fuel (vapor) is generated by vaporizing the fuel, and a canister is provided to prevent the vaporized fuel from unnecessarily diffusing into the atmosphere.

  The canister is filled with an adsorbent such as activated carbon and adsorbs and collects evaporated fuel. The collected evaporated fuel is purged through the purge passage into the intake passage of the internal combustion engine when the internal combustion engine is operated. Thereby, it is comprised so that breakthrough (outflow) of the evaporative fuel from a canister drain may be reduced.

  By the way, after the fuel is supplied to the fuel tank, the operation of the internal combustion engine may be stopped for a long period of time. In particular, in a hybrid system that uses an internal combustion engine and a motor in combination, only traveling by the motor is performed, and the operation of the internal combustion engine may not be performed for a long period of time.

  At that time, a large amount of evaporated fuel is likely to be generated in the fuel tank, while the frequency of purging the evaporated fuel from the canister is extremely reduced. For this reason, the evaporated fuel that cannot be collected by the canister may be released into the atmosphere.

  Therefore, for example, a control device for a generator driving engine disclosed in Patent Document 1 is known. This patent document 1 is mounted on an electric vehicle having an engine that receives supply of fuel from a fuel tank and a generator that generates power by being driven by mechanical output of the engine, and at least a control device that controls the operation of the engine. Means for detecting the amount of fuel vapor in the fuel tank in a stopped state, means for starting the engine when the detected amount of vapor exceeds a first predetermined amount, and the engine is operating Means for detecting the amount of fuel vapor in the fuel tank in the state, and means for stopping the engine when the detected amount of vapor becomes equal to or less than a second predetermined amount, wherein the second predetermined amount is It is characterized by being smaller than the first predetermined amount.

Japanese Patent Laid-Open No. 06-233410

  By the way, if the internal combustion engine is not driven for a long period of time, the evaporated fuel adsorbed by the canister tends to leak to the outside as time elapses. However, in the above-mentioned Patent Document 1, only the purge process is performed by detecting the amount of fuel vapor in the fuel tank, and there is a problem that breakthrough from the canister that occurs over time cannot be reduced. is there.

  The present invention solves this type of problem, and when the internal combustion engine is stopped for a long period of time, it is possible to reliably prevent breakthrough from the canister that is likely to occur with the passage of time. An object of the present invention is to provide an apparatus and a purging method thereof.

  The present invention includes a first communication path for introducing evaporated fuel generated in a fuel tank that stores fuel, a canister connected to the first communication path and adsorbing the evaporated fuel, and intake air of the canister and an internal combustion engine The present invention relates to an evaporative fuel processing apparatus comprising: a second communication path that communicates with a passage; and a purge processing unit that purges the evaporated fuel adsorbed by the canister to the internal combustion engine through the second communication path. .

The fuel vapor processing apparatus, when the fuel in the fuel tank is fueling, the adsorption amount detection mechanism for detecting the amount of adsorbed fuel vapor adsorbed in the canister through the oil supply, actually in a state where the internal combustion engine is stopped , the time from the canister to the canister breakthrough when the vaporized fuel to the internal combustion engine is not purged, the breakthrough time calculating mechanism configured to calculate, based on the detected amount of adsorption, the time calculated And a control mechanism for performing a purge process by the purge process unit.

  Moreover, it is preferable that the adsorption amount detection mechanism includes a fuel supply amount detection unit that detects a fuel supply amount of fuel supplied to the fuel tank, and detects the adsorption amount based on the detected fuel supply amount.

  Furthermore, it is preferable that the adsorption amount detection mechanism includes a temperature change detection unit that detects a temperature change of the canister when fuel is supplied to the fuel tank, and detects the adsorption amount based on the detected temperature change.

  Furthermore, the present invention provides a first communication path for introducing evaporated fuel generated in a fuel tank for storing fuel, a canister connected to the first communication path and adsorbing the evaporated fuel, the canister and an internal combustion engine An evaporative fuel processing apparatus comprising: a second communication path that communicates with an intake passage of an engine; and a purge processing unit that purges the evaporated fuel adsorbed by the canister to the internal combustion engine through the second communication path. The present invention relates to a purge method.

The purging method, when the fuel in the fuel tank is fueling, and detecting the amount of adsorbed fuel vapor adsorbed in the canister through the oil supply, actually in a state where the internal combustion engine is stopped, the from the canister Calculating the time until the canister breaks through when the evaporated fuel is not purged into the internal combustion engine based on the detected adsorption amount, and purging by the purge processing unit based on the calculated time And a step of performing processing.

  The purge method preferably includes a step of detecting the amount of fuel supplied to the fuel tank and a step of detecting the amount of adsorption based on the detected amount of fuel supplied.

  Further, the purge method preferably includes a step of detecting a temperature change of the canister when the fuel tank is supplied with fuel, and a step of detecting an adsorption amount based on the detected temperature change.

  In the present invention, the canister that has adsorbed the evaporated fuel by refueling can be purged before breaking through as time passes. This makes it possible to reliably prevent breakthrough from the canister when the internal combustion engine is stopped for a long period of time, particularly in a hybrid system.

  In addition, the adsorption state of the canister can be detected with high accuracy. For this reason, it becomes possible to suppress the operation time of the internal combustion engine to a necessary minimum, and it is economical to reduce fuel consumption.

  FIG. 1 is a schematic configuration diagram of a fuel tank system 10 to which an evaporative fuel processing apparatus according to a first embodiment of the present invention is applied. The fuel tank system 10 is particularly preferably used in a hybrid system that uses both an engine (not shown) and a motor (not shown).

  The fuel tank system 10 is connected to the fuel tank 12 for storing the fuel F, the vapor passage (first communication passage) 16 for introducing the evaporated fuel (vapor) in the fuel tank 12 from the float 14, and the vapor passage 16. The canister 18 that adsorbs the evaporated fuel, the drain passage 20 that communicates the canister 18 with the outside air and introduces external air into the canister 18 when the evaporated fuel is purged, and the canister 18 A purge passage (second communication passage) 22 for sucking (purging) the evaporated fuel into an intake passage communicating with the engine (not shown) when the engine is driven, and an ECU (electronic control unit) 24 are provided.

  One end of an oil supply pipe member 26 is attached to the fuel tank 12. A cap 28 is attached to the other end portion of the oil supply pipe member 26, and a breather pipe 30 is provided from the vicinity of the cap 28 toward the space S of the fuel tank 12.

  In the fuel tank 12, a fuel pump 32 for supplying the fuel F stored in the fuel tank 12 to the engine, and a fuel supply amount detection unit for detecting the fuel supply amount of the fuel F supplied to the fuel tank 12. (For example, float) 34 is arranged.

  The canister 18 is filled with an adsorbent (not shown) such as activated carbon. A sealing valve 36 is disposed in the vapor passage 16. The drain passage 20 and the purge passage 22 are provided with a drain control valve 38a and a purge control valve 38b. The purge control valve 38b constitutes a purge processing unit that purges the evaporated fuel adsorbed by the canister 18 into the internal combustion engine.

  The ECU 24 includes an adsorption amount detection circuit (adsorption amount detection mechanism) 42 that detects an adsorption amount of the evaporated fuel adsorbed to the canister 18 when the fuel F is supplied to the fuel tank 12, and an engine from the canister 18. And a breakthrough time calculation circuit (breakthrough time calculation mechanism) 44 for calculating a time until the canister 18 breaks through when the evaporated fuel is not purged based on the detected adsorption amount. And a control circuit (control mechanism) 46 that starts the engine and opens the purge control valve 38b based on the time to perform the purge process. The control circuit 46 is connected with a timer 48 as a time measuring means.

  The adsorption amount detection circuit 42 includes an oil supply amount detection unit 34, and detects the adsorption amount of the evaporated fuel adsorbed by the canister 18 based on the oil supply amount detected through the oil supply amount detection unit 34.

  For example, as shown in FIG. 2, the control circuit 46 has a relationship between the oil supply amount and the adsorption amount as a map or a calculation formula in advance. Here, when the oil supply amount is x, the adsorption amount is y. However, when the fuel tank 12 is a closed tank, the pressure in the fuel tank 12 is released when refueling. In actuality, the amount of vapor corresponding to the pressure release flows out to the canister 18 and is adsorbed. Therefore, when it is necessary to release pressure during refueling, such as in a closed tank, the amount of adsorption due to the amount of vapor flowing out to the canister 18 is added to the amount of adsorption y calculated from the relationship of FIG. It is preferable to calculate a substantial amount of adsorption.

  For example, as shown in FIG. 3, the control circuit 46 has a relationship between the amount of adsorption and the breakthrough time of the canister 18 and the presence or absence of breakthrough as a map or a calculation formula.

  The vapor passage 16, the canister 18, the purge passage 22, the purge control valve 38 b, the fuel supply amount detection unit 34, and the ECU 24 constitute the evaporated fuel processing device 50 according to the first embodiment.

  The operation of the fuel tank system 10 configured as described above will be described below along the flowchart shown in FIG. 4 in relation to the purge method according to the first embodiment.

  First, the cap 28 attached to the other end of the oil supply pipe member 26 is removed, and the fuel F is injected into the oil supply pipe member 26. Therefore, the fuel F is supplied to the fuel tank 12 (step S1), and a predetermined amount of the fuel F is stored in the fuel tank 12.

  The fuel supply to the fuel tank 12 is completed, and the fuel supply amount in the fuel tank 12 is detected via the fuel supply amount detection unit 34 (step S2). The adsorption amount detection circuit 42 determines the adsorption amount of the evaporated fuel adsorbed by the canister 18 based on the oil supply amount detected via the oil supply amount detection unit 34 from the relationship between the oil supply amount and the adsorption amount shown in FIG. Detect (step S3).

  Next, if it is determined that there is a possibility of breakthrough in the canister 18 based on the detected adsorption amount (YES in step S4), the process proceeds to step S5, and the breakthrough time of the canister 18 is calculated. (See FIG. 3). When the calculated breakthrough time × k (where k ≦ 1) is counted (YES in step S6), the control circuit 46 proceeds to step S7 and performs a purge process.

  In this purge process, an engine (not shown) is started, and the fuel F stored in the fuel tank 12 is supplied to the engine via the fuel pump 32. On the other hand, when air is supplied to the engine, a negative pressure is generated in the intake passage (not shown), and the evaporated fuel collected in the canister 18 is under the opening action of the purge control valve 38b. The air is sucked into the purge passage 22 and purged.

  At this time, the drain control valve 38a is opened, so that outside air flows from the drain passage 20 into the canister 18. Accordingly, the evaporated fuel adsorbed in the canister 18 is purged into the intake passage together with the inflowing outside air.

  If it is determined in step S4 that there is no possibility of breakthrough in the canister 18 based on the detected adsorption amount (NO in step S4), the process is terminated without performing the purge process.

  In this case, in the first embodiment, before the canister 18 that has adsorbed the evaporated fuel by supplying fuel to the fuel tank 12 breaks through as time elapses, the engine is started and the canister 18 in the canister 18 is The evaporated fuel can be purged. Thereby, especially in a hybrid system, when the engine is stopped for a long period of time, it is possible to reliably prevent breakthrough from the canister 18.

  In addition, the adsorption state of the canister 18 can be detected with high accuracy. For this reason, it becomes possible to suppress the operating time of the engine to the minimum necessary, and there is an advantage that it is economical by reducing fuel consumption.

  FIG. 5 is a flowchart for explaining the purge method according to the second embodiment of the present invention. Detailed description of the same steps as those of the purge method according to the first embodiment shown in FIG. 4 will be omitted.

  In the second embodiment, the steps (step S15) after the fuel tank 12 is refueled (step S11) until the breakthrough time of the canister 18 is calculated are the steps S1 to S1 of the first embodiment. The same as S5.

  Then, before the breakthrough time of the canister 18 elapses, when the engine is started (NO in step S16), the process returns to step S12 to detect the amount of fuel supplied in the fuel tank 12. Furthermore, if it is determined that there is a possibility of breakthrough in the canister 18 based on the remaining amount of fuel supply (YES in step S14), the processing from step S15 is performed.

  As described above, in the second embodiment, when the engine is started before the breakthrough time of the canister 18 elapses, the variation in the adsorption amount of the canister 18 that varies depending on the operation time of the engine is taken into consideration. The breakthrough time of the canister 18 can be calculated again. As a result, the state of the canister 18 can be detected with higher accuracy, and an advantageous effect that a good purge process is reliably performed can be obtained.

  FIG. 6 is a schematic configuration diagram of a fuel tank system 60 to which the evaporated fuel processing apparatus according to the third embodiment of the present invention is applied. The fuel tank system 60 is configured in the same manner as the fuel tank system 10, and the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel tank system 60 is driven and controlled via an ECU (electronic control unit) 62. The ECU 62 includes an adsorption amount detection circuit (adsorption amount detection mechanism) 64 that detects an adsorption amount of the evaporated fuel that is adsorbed to the canister 18 when the fuel F is supplied to the fuel tank 12, and an internal combustion engine from the canister 18. Based on the calculated breakthrough time calculation circuit 44 that calculates the time until the canister 18 breakthrough when the evaporated fuel is not purged in the engine based on the detected adsorption amount, And a control circuit 46 for starting the engine and opening the purge control valve 38b to perform the purge process.

  The adsorption amount detection circuit 64 includes a temperature change detection unit that detects a temperature change of the canister 18 when fuel is supplied to the fuel tank 12, for example, a plurality of temperature sensors T1 to T6. Each temperature sensor T <b> 1 to T <b> 6 is sequentially arranged along the flow direction from the inlet to the outlet in the canister 18 in order to detect a temperature change for each area in the canister 18. The adsorption amount detection circuit 64 detects the adsorption amount of the canister 18 based on the detected temperature change.

  For example, as shown in FIG. 7, the control circuit 46 calculates the amount of adsorption in the canister 18 by detecting whether or not the temperature sensors T1 to T6 have reached the adsorbed temperature. At that time, the relationship between the detected temperature of each temperature sensor T1 to T6 and the amount of adsorption is calculated based on FIG.

  The vapor passage 16, the canister 18, the purge passage 22, the purge control valve 38b, the temperature sensor 66, and the ECU 62 constitute an evaporated fuel processing device 68 according to the third embodiment.

  The operation of the fuel tank system 60 configured as described above will be described below along the flowchart shown in FIG. 9 in relation to the purge method according to the third embodiment. Detailed description of the same steps as those of the purge method according to the first embodiment shown in FIG. 4 will be omitted.

  First, when fuel is supplied to the fuel tank 12 (step S21), evaporative fuel is introduced into the canister 18, so that the canister 18 adsorbs the evaporative fuel. At that time, heat generation due to adsorption occurs in the canister 18, and each temperature sensor T <b> 1 to T <b> 6 detects an increase in temperature for each area in the canister 18.

  As shown in FIG. 7, the adsorption amount detection circuit 42 canister 18 from the number of sensors that have reached the adsorbed temperature among the temperature sensors T1 to T6 and the relationship between the sensor detection temperature and the adsorption amount shown in FIG. The adsorption amount of the evaporated fuel adsorbed by is detected (step S23). Subsequently, the processing after step S24 is performed.

  In this case, in the third embodiment, before the canister 18 that has adsorbed the evaporated fuel by supplying fuel to the fuel tank 12 breaks through with the passage of time, the engine is started and the canister 18 in the canister 18 is The evaporated fuel can be purged, and the same effect as in the first embodiment can be obtained.

  In the third embodiment, as in the second embodiment, when the engine is started before the breakthrough time of the canister 18 elapses, the canister 18 varies depending on the operation time of the engine. The breakthrough time of the canister 18 can be calculated again in consideration of the fluctuation of the adsorption amount.

1 is a schematic configuration diagram of a fuel tank system to which an evaporated fuel processing apparatus according to a first embodiment of the present invention is applied. It is a relationship diagram between the amount of oil supply and the amount of adsorption. It is a related figure of adsorption amount and breakthrough time. It is a flowchart explaining the purge method which concerns on the 1st Embodiment of this invention. It is a flowchart explaining the purge method which concerns on the 2nd Embodiment of this invention. It is a schematic block diagram of the fuel tank system with which the evaporative fuel processing apparatus which concerns on the 3rd Embodiment of this invention is applied. It is a related figure of the ultimate temperature at the time of adsorption | suction of each temperature sensor, and time. It is a related figure of detection temperature of each temperature sensor, and adsorption amount. It is a flowchart explaining the purge method which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 60 ... Fuel tank system 12 ... Fuel tank 16 ... Vapor passage 18 ... Canister 20 ... Drain passage 22 ... Purge passage 24, 62 ... ECU26 ... Refueling pipe member 32 ... Fuel pump 34 ... Refueling amount detection part 36 ... Sealing part 38a ... Drain control valve 38b ... Purge control valve 42, 64 ... Adsorption amount detection circuit 44 ... Breakthrough time calculation circuit 46 ... Control circuit 48 ... Timer 50, 68 ... Evaporated fuel processing devices T1-T6 ... Temperature sensor

Claims (6)

A first communication path for introducing evaporated fuel generated in a fuel tank for storing fuel;
A canister connected to the first communication path and adsorbing the evaporated fuel;
A second communication passage communicating the canister and the intake passage of the internal combustion engine;
A purge processing unit for purging the evaporated fuel adsorbed by the canister to the internal combustion engine through the second communication path;
An evaporative fuel processing apparatus comprising:
An adsorption amount detection mechanism for detecting an adsorption amount of the evaporated fuel adsorbed by the canister when the fuel is supplied to the fuel tank;
Indeed in a state where the internal combustion engine is stopped, the time from the canister to the fuel vapor to the internal combustion engine is the canister breakthrough if not purged, is calculated based on the detected amount of adsorption A breakthrough time calculation mechanism,
A control mechanism for performing a purge process by the purge process unit based on the calculated time;
An evaporative fuel processing apparatus comprising: The evaporated fuel processing apparatus according to claim 1, wherein the adsorption amount detection mechanism includes a fuel supply amount detection unit that detects a fuel supply amount of the fuel supplied to the fuel tank,
An evaporative fuel processing apparatus that detects the amount of adsorption based on the detected amount of fuel supply. The evaporated fuel processing apparatus according to claim 1, wherein the adsorption amount detection mechanism includes a temperature change detection unit that detects a temperature change of the canister when fuel is supplied to the fuel tank.
An evaporative fuel processing apparatus, wherein the adsorption amount is detected based on the detected temperature change. A first communication path for introducing evaporated fuel generated in a fuel tank for storing fuel;
A canister connected to the first communication path and adsorbing the evaporated fuel;
A second communication passage communicating the canister and the intake passage of the internal combustion engine;
A purge processing unit for purging the evaporated fuel adsorbed by the canister to the internal combustion engine through the second communication path;
A method for purging an evaporative fuel processing apparatus comprising:
Detecting the adsorbed amount of the evaporated fuel adsorbed by the canister when the fuel is supplied to the fuel tank;
Indeed in a state where the internal combustion engine is stopped, the time from the canister to the fuel vapor to the internal combustion engine is the canister breakthrough if not purged, is calculated based on the detected amount of adsorption Process,
A step of performing a purge process by the purge process unit based on the calculated time;
A method for purging an evaporative fuel processing apparatus, comprising: 5. The purging method according to claim 4, wherein a fuel supply amount of the fuel supplied to the fuel tank is detected.
Detecting the adsorption amount based on the detected oil supply amount;
A method for purging an evaporative fuel processing apparatus, comprising: 5. The purge method according to claim 4, wherein detecting a temperature change of the canister when the fuel tank is refueled;
Detecting the amount of adsorption based on the detected temperature change;
A method for purging an evaporative fuel processing apparatus, comprising:

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