JP4784307B2 - Evaporative fuel processing equipment - Google Patents

Description

  The present invention relates to an apparatus for processing evaporated fuel generated in a fuel tank.

  2. Description of the Related Art Conventionally, there is known an evaporated fuel processing apparatus that purges and processes evaporated fuel generated in a fuel tank into an intake passage of an internal combustion engine. As this type of device, a technique for forcibly purging the evaporated fuel desorbed from the canister to the intake passage by generating a fluid flow by a pump in a purge passage connected to the intake passage and in which the canister is arranged is proposed. (For example, refer to Patent Document 1).

Japanese Patent No. 3338644

  However, in the apparatus disclosed in Patent Document 1, the discharge side of the pump in the purge passage is connected to the intake passage, while the suction side of the pump in the purge passage is connected to a canister and a fuel tank that are different pressure systems from the intake passage. It is connected. Therefore, when the pressure in the intake passage varies according to the operating condition of the internal combustion engine, the differential pressure generated between the suction side and the discharge side of the pump in the purge passage varies.

Here, FIG. 25 shows how the correlation between the pump rotation speed and the pump flow rate changes in accordance with the differential pressure between the suction side and the discharge side of the pump. As can be seen from the figure, when the differential pressure between the suction side and the discharge side of the pump increases, the pump flow rate increases even when the pump rotation speed is the same. Therefore, when the differential pressure generated between the suction side and the discharge side of the pump varies in the purge passage as in the device disclosed in Patent Document 1, the rotational speed (N) -flow rate (Q) characteristic of the pump is unstable. As a result, it becomes difficult to control the purge flow rate from the purge passage to the intake passage.
The present invention has been made in view of such problems, and an object of the present invention is to provide an evaporative fuel processing apparatus that controls the purge flow rate to the intake passage with high accuracy.

Claim 1, according to the invention described in our and 2, on the upstream side or downstream side first port and the second port of the throttle valve is one end and the other end of the purge passage is connected in the intake passage, the purge passage , The pump discharges the fluid sucked from the second port side to the first port side. In this configuration, the pressure on the second port side that is the suction side of the pump in the purge passage and the pressure on the first port side that is the discharge side of the pump in the purge passage are substantially equal to each other in accordance with pressure fluctuations in the intake passage. Fluctuate by the same amount. Therefore, even if the pressure in the intake passage varies depending on the operating condition of the internal combustion engine, the differential pressure generated between the suction side and the discharge side of the pump in the purge passage is difficult to vary. Is stable. Therefore, according to claim 1, according to the invention described in our and 2, a purge flow from the purge passage into the intake passage can be precisely controlled by the pump.

According to the fifth aspect of the present invention, since the pressure fluctuation in the upstream side of the throttle valve in the intake passage is smaller than that in the downstream side, the pump passage is connected to the first port and the second port on the upstream side. The pressure fluctuation itself is suppressed on the suction side and the discharge side. Therefore, it is effective in reducing the fluctuation of the differential pressure generated between the suction side and the discharge side of the pump.

According to the third and fourth aspects of the invention, one end and the other end of the purge passage are respectively connected to the first port and the second port in the intake passage of the throttleless internal combustion engine, and the pump is connected to the second port in the purge passage. The fluid sucked from the side is discharged to the first port side. In this configuration, the pressure on the second port side that is the suction side of the pump in the purge passage and the pressure on the first port side that is the discharge side of the pump in the purge passage are substantially equal to each other in accordance with pressure fluctuations in the intake passage. Fluctuate by the same amount. Therefore, even if the pressure in the intake passage varies depending on the operating condition of the internal combustion engine, the differential pressure generated between the suction side and the discharge side of the pump in the purge passage is difficult to vary. Is stable. Therefore, according to the fourth aspect of the invention, the purge flow rate from the purge passage to the intake passage can be controlled with high accuracy by the pump.

According to the sixth aspect of the present invention, since the purge passage is connected to the first port downstream of the second port in the intake passage, the evaporated fuel purged from the purge passage through the first port is purged through the second port. It is possible to prevent recirculation to the passage. Therefore, it is possible to avoid a situation in which the supply flow rate of the evaporated fuel to the internal combustion engine deviates from the purge flow rate by the pump and affects the operation of the internal combustion engine.

According to the seventh aspect of the present invention, in the purge period for purging the evaporated fuel into the intake passage, the first opening / closing valve opens the purge passage on the first port side of the canister, and the second opening / closing valve is the second opening of the canister. Open the purge passage on the port side. Therefore, during the purge period, the evaporated fuel can be desorbed from the canister using the fluid flow generated by the suction and discharge action of the pump and purged through the first port. Further, outside the purge period, for example, the first on-off valve and the second on-off valve each close the purge passage, thereby prohibiting the purge to the intake passage.

According to the eighth aspect of the invention, in the purge period, after the first opening / closing valve opens the purge passage, the second opening / closing valve opens the purge passage. It acts on the first port side of the canister before the two port side. Therefore, for example, when the pressure of the intake passage is lower than that of the purge passage, it is possible to avoid a situation in which the pressure of the intake passage acts on the second port side of the canister and the adsorbed fuel of the canister leaks to the second port side.

According to the ninth aspect of the present invention, in the purge period, after the second opening / closing valve opens the purge passage, the first opening / closing valve opens the purge passage. It acts on the second port side of the canister before the one port side. Therefore, for example, when the pressure of the intake passage is lower than that of the purge passage, it is possible to avoid a situation where the pressure of the intake passage acts on the first port side of the canister and the adsorbed fuel of the canister leaks to the first port side. Here, the fuel leakage due to the action of the pressure in the intake passage allows a purge not based on the flow rate control of the pump, but according to the invention of claim 7 , the fuel leakage is avoided. Accurate purging according to the flow rate control can be realized.
According to the invention described in claim 10 , the first on-off valve purge passage is opened after the pump is started in the purge period. Therefore, since the purge to the intake passage is started at the same time as the first opening / closing valve opens the purge passage, the target purge flow rate can be achieved quickly.

According to the eleventh aspect of the present invention, in the purge period, the first on-off valve and the second on-off valve each open the purge passage and the pump is started at the same time. Therefore, since the purge passage is opened by the first on-off valve and the second on-off valve, the purge to the intake passage is started at the same time, so that the target purge flow rate can be achieved quickly and the pump flow rate control is performed. Can prevent no purging.

According to the twelfth aspect of the present invention, the valve member common to the first on-off valve and the second on-off valve moves to the first switching position or the second switching position, so that the first port side and the second port of the canister The purge passage is opened or closed on both sides. That is, since the function of the first on-off valve and the function of the second on-off valve can be realized by the movement of the common valve member, it is possible to reduce the number of parts related to the opening and closing of the purge passage and contribute to cost reduction.

According to the first, third, and thirteenth aspects, the other end of the atmospheric passage whose one end is opened to the atmosphere is connected between the canister and the second opening / closing valve in the purge passage, and the third opening / closing is performed during the purge period. The valve closes the atmospheric passage. By closing the air passage in this way, it is possible to prevent air from being introduced into the intake passage from other than the intake passage during the purge period, so that the actual intake amount of the internal combustion engine deviates from the normal intake amount through the intake passage. Can be avoided. Further, outside the purge period, for example, the third on-off valve opens the atmosphere passage, so that the canister, the fuel tank communicating with the canister, and the like can be opened to the atmosphere to suppress an increase in internal pressure.
According to the fourteenth aspect of the present invention, since the first on-off valve and the second on-off valve each open the purge passage after the third on-off valve closes the air passage during the purge period, the air is sucked from other than the intake passage. It can be reliably prevented from being introduced into the passage.

According to the invention described in claims 2, 4 and 15 , the other end of the atmospheric passage whose one end is opened to the atmosphere is connected to the second port side of the canister in the purge passage, and the purge passage is connected to the atmospheric passage. The second on-off valve disposed in the section not only opens the purge passage during the purge period but also closes the atmospheric passage. By closing the air passage in this way, it is possible to prevent air from being introduced into the intake passage from other than the intake passage during the purge period, so that the actual intake amount of the internal combustion engine deviates from the normal intake amount through the intake passage. Can be avoided. Further, outside the purge period, for example, the second on-off valve closes the purge passage and opens the atmospheric passage, whereby the canister and the fuel tank communicating therewith can be opened to the atmosphere to suppress an increase in internal pressure. Furthermore, since the second on-off valve that opens and closes the purge passage also fulfills the opening and closing function of the atmospheric passage, the number of parts relating to the opening and closing of the purge passage and the atmospheric passage can be reduced, thereby contributing to cost reduction.
According to the invention described in claim 16 , during the purge period, after the second on-off valve closes the air passage, the first on-off valve opens the purge passage, so that air is introduced into the intake passage from other than the intake passage. Can be reliably prevented.

According to the seventeenth aspect of the present invention, the pump is disposed on the first port side of the canister in the purge passage. Accordingly, the control response of the purge flow rate can be improved by bringing the pump as close to the first port as possible.
According to the eighteenth aspect of the present invention, since the pump is arranged on the second port side of the canister in the purge passage, it is possible to avoid a situation in which the desorbed fuel from the canister is sucked into the pump. Therefore, it is possible to prevent the inside of the pump from being deteriorated by being exposed to the evaporated fuel.

According to the nineteenth aspect of the invention, since the positive displacement pump whose NQ characteristic is relatively stable is used as the pump, the purge flow rate can be controlled with higher accuracy.
In addition, as the “pump” in the inventions according to claims 1 to 18 , a pump other than a positive displacement pump may be used.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment.
(First embodiment)
FIG. 1 shows an evaporated fuel processing apparatus (hereinafter referred to as “processing apparatus”) 10 according to a first embodiment of the present invention. The processing device 10 is mounted on a vehicle, processes the evaporated fuel generated in the fuel tank 2 and purges it to the intake passage 3 of the internal combustion engine. Here, the internal combustion engine to which the processing device 10 is applied has the throttle valve 4 for adjusting the intake air amount in the intake passage 3, and the first port 6 and the second port 8 on the upstream side of the throttle valve 4 in the intake passage 3. Is provided. Further, in this internal combustion engine, the first port 6 is arranged downstream of the second port 8, and the evaporated fuel purged to the intake passage 3 through the first port 6 returns to the processing device 10 through the second port 8. To prevent it.

The processing apparatus 10 includes a purge passage 11, a canister 12, a pump 14, a first on-off valve 22, a second on-off valve 24, an atmospheric passage 25, a third on-off valve 26, and an electronic control unit (hereinafter, the electronic control unit is referred to as an ECU). 27 etc.
One end of the purge passage 11 is connected to the first port 6 of the intake passage 3, and the other end of the purge passage 11 is connected to the second port 8 of the intake passage 3.

  The canister 12 is formed by filling a case 19 with an adsorbent 18 such as activated carbon, and is disposed in the purge passage 11. Thereby, the purge passage 11 is divided into the first port side 11a and the second port side 11b rather than the canister 12, and the canister 12 is formed on both sides of the adsorbent 18 between the first port side 11a and the second port side 11b. It is connected to the. In the following description, the first port side 11a of the canister 12 in the purge passage 11 is referred to as a first passage portion 11a, and the second port side 11b of the canister 12 in the purge passage 11 is referred to as a second passage portion 11b.

  The canister 12 is further connected to the upper part of the fuel tank 2 through the tank passage 20. Therefore, the evaporated fuel generated in the fuel tank 2 flows into the canister 12 through the tank passage 20 and is adsorbably adsorbed on the adsorbent 18 of the canister 12. Here, the tank passage 20 is connected to the canister 12 on the opposite side to the second passage portion 11b of the purge passage 11 with the adsorbent 18 interposed therebetween, thereby preventing direct communication with the second passage portion 11b. Has been. Further, the tank passage 20 is prevented from communicating directly with the first passage portion 11a of the purge passage 11 by partitioning the inside of the case 19 by the partition plate 19a.

  The pump 14 is an electric pump and is disposed in the purge passage 11. Particularly in this embodiment, a positive displacement pump such as a vane pump is used as the pump 14, and the pump 14 is disposed in the second passage portion 11 b of the purge passage 11. Therefore, the pump 14 discharges the fluid sucked from the second port side in the second passage portion 11b to the first port side, that is, the canister side here, by the operation of a built-in electric motor (not shown).

  The first on-off valve 22 is an electromagnetically driven on / off valve, and is disposed in the first passage portion 11 a of the purge passage 11. The first on-off valve 22 opens and closes the first passage portion 11a by its on / off operation. Therefore, when the first on-off valve 22 opens the first passage portion 11a, the pressure of the first passage portion 11a changes according to the pressure on the upstream side of the throttle valve 4 in the intake passage 3 (hereinafter simply referred to as upstream pressure). To do.

  The second on-off valve 24 is an electromagnetically driven on / off valve, and is disposed between the second port 8 and the pump 14 in the second passage portion 11 b of the purge passage 11. The second on-off valve 24 opens and closes the second passage portion 11b by its on / off operation. Therefore, when the second on-off valve 24 opens the second passage portion 11b, the pressure of the second passage portion 11b changes according to the upstream pressure of the intake passage 3.

One end of the atmospheric passage 25 is opened to the atmosphere, and the other end of the atmospheric passage 25 is between the pump 14 and the second on-off valve 24 in the second passage portion 11b of the purge passage 11, that is, here, the canister 12 and the second on-off valve. 24.
The third on-off valve 26 is an electromagnetically driven on / off valve, and is disposed between the atmosphere opening end in the atmosphere passage 25 and the connection end for the second passage portion 11b. The third on-off valve 26 opens and closes the atmospheric passage 25 by its on / off operation. Therefore, when the third on-off valve 26 opens the atmospheric passage 25, the purge passage 11 and the canister 12 are opened to the atmosphere.

  The ECU 27, which is a control means, is mainly composed of a microcomputer having a CPU and a memory. The ECU 27 is electrically connected to the valves 22, 24, 26 and the pump 14, and controls the on / off operation of the valves 22, 24, 26 and the rotational speed of the pump 14. Note that the ECU 27 may or may not have a function of controlling the internal combustion engine.

Next, a purge control process performed by the processing apparatus 10 during the purge period will be described with reference to the flowchart of FIG.
The purge control process starts when the purge start condition is satisfied after the internal combustion engine is started. Here, the establishment of the purge start condition means that physical quantities representing the vehicle state, such as the coolant temperature of the internal combustion engine, the rotational speed of the internal combustion engine, and the hydraulic oil temperature of the vehicle, are in a predetermined region. At the start of the purge control process, the first opening / closing valve 22 and the second opening / closing valve 24 close the first passage portion 11a and the second passage portion 11b of the purge passage 11, and the third opening / closing valve. 26, the air passage 25 is opened, and the pump 14 is stopped.

In step S11 (hereinafter, “step S” is abbreviated as “S”) of the purge control process, the ECU 27 controls the third on-off valve 26 to close the atmospheric passage 25.
In subsequent S12, the ECU 27 controls the first on-off valve 22 and the second on-off valve 24 to open the first passage portion 11a and the second passage portion 11b of the purge passage 11, and simultaneously starts the pump 14. As a result, the air in the intake passage 3 is sucked into the pump 14 through the second port 8 and the second passage portion 11b, and is discharged to the canister side in the second passage portion 11b. Then, by this discharge pressure, the evaporated fuel is desorbed from the adsorbent 18 of the canister 12 and flows into the first passage portion 11 a, and is forcibly purged to the intake passage 3 through the first port 6. Here, the evaporated fuel purged into the intake passage 3 is combusted in the cylinder of the internal combustion engine together with the fuel injected from the fuel injection valve (not shown) of the internal combustion engine, so that the purge flow rate of the evaporated fuel is controlled. Is important. Therefore, in this embodiment, the ECU 27 controls the purge flow rate by controlling the rotation speed of the pump 14 in S13.

When the purge stop condition is satisfied during the forced purge, the ECU 27 controls the first on-off valve 22 and the second on-off valve 24 to close the first passage portion 11a and the second passage portion 11b in S14, and at the same time, the pump 14 Stop. This stops the forced purge. Here, the establishment of the purge stop condition means that a physical quantity representing the state of the vehicle, such as the rotational speed of the internal combustion engine, the accelerator opening of the vehicle, etc., is in a predetermined region different from the purge start condition.
In subsequent S15, the ECU 27 controls the third on-off valve 26 to open the atmospheric passage 25. As a result, the purge control process ends.

  According to the first embodiment described above, the passage portions 11a and 11b of the purge passage 11 are opened on both sides of the pump 14 prior to the purge of the evaporated fuel. Thus, the pressure on the second port side that is the suction side of the pump 14 in the purge passage 11 and the pressure on the first port side that is the discharge side of the pump 14 in the purge passage 11 are the upstream pressure of the intake passage 3. It changes by almost the same amount according to the fluctuation of. Therefore, even if the pressure on the upstream side of the intake passage 3 fluctuates in accordance with the operating state of the internal combustion engine, the pressure difference generated between the suction side and the discharge side of the pump 14 in the purge passage 11 is less likely to fluctuate. 14 NQ characteristics are stabilized.

Further, according to the first embodiment, the evaporated fuel purged from the purge passage 11 to the intake passage 3 through the first port 6 returns to the purge passage 11 through the second port 8 upstream of the first port 6. To be prevented. Therefore, it is possible to avoid a situation where the supply flow rate of the evaporated fuel to the internal combustion engine deviates from the purge flow rate controlled by the pump 14. Further, according to the first embodiment, prior to evaporative fuel purging, the passages 11a and 11b are opened, and at the same time, the pump 14 is activated to start purging. Accordingly, the target purge flow rate can be achieved quickly, and purging not based on the flow rate control of the pump 14 can be prevented.
According to the first embodiment as described above, the purge flow rate to the intake passage 3 can be controlled with high accuracy by the pump 14, so that a purge flow rate suitable for the operation of the internal combustion engine can be realized sequentially.

  Furthermore, according to the first embodiment, the atmospheric passage 25 is closed prior to the opening of the passage portions 11a and 11b and the purge of the evaporated fuel. As a result, it is possible to reliably prevent the atmosphere from being introduced into the intake passage 3 from other than the intake passage 3, so that a situation in which the actual intake amount of the internal combustion engine deviates from the normal intake amount through the intake passage 3 can be avoided. In addition, according to the first embodiment, the pump 14 is disposed in the purge passage 11 between the canister 12 and the second on-off valve 24, that is, on the second port 8 side of the canister 12. As a result, it is possible to avoid a situation in which the desorbed fuel from the canister 12 is sucked into the pump 14, thereby preventing the inside of the pump 14 from being exposed to the evaporated fuel and deteriorating.

(Second embodiment)
As shown in FIG. 3, in the purge control process according to the second embodiment of the present invention, S21 and S25 to S27 having contents similar to S11 and S13 to S15 of the first embodiment are performed, while S12 of the first embodiment is performed. S22 to S24 are performed instead of.
Specifically, in S <b> 22, the ECU 27 controls the first opening / closing valve 22 to open the first passage portion 11 a of the purge passage 11. In subsequent S23, the ECU 27 controls the second opening / closing valve 24 to open the second passage portion 11b of the purge passage 11. Further in S24, the ECU 27 activates the pump 14. As a result, the air in the intake passage 3 is sucked into the pump 14 through the second port 8 and the second passage portion 11b and discharged to the canister side in the second passage portion 11b, so that the desorbed fuel from the canister 12 is the first. The intake passage 3 is forcibly purged through the port 6.

  According to the second embodiment, the first passage portion 11a of the purge passage 11 is opened before the second passage portion 11b of the purge passage 11 prior to the purge of the evaporated fuel. Therefore, when the upstream pressure of the intake passage 3 is lower than the purge passage 11, the situation where the upstream pressure acts on the second passage portion 11b and the adsorbed fuel of the canister 12 leaks to the second passage portion 11b is avoided. it can.

(Third embodiment)
As shown in FIG. 4, in the purge control process according to the third embodiment of the present invention, S31 and S35 to S37 having contents similar to S11 and S13 to S15 of the first embodiment are performed, while S12 of the first embodiment is performed. S32 to S34 are performed instead of.
Specifically, in S <b> 32, the ECU 27 controls the second opening / closing valve 24 to open the second passage portion 11 b of the purge passage 11. In subsequent S33, the ECU 27 controls the first on-off valve 22 to open the first passage portion 11a of the purge passage 11. Further in S34, the ECU 27 activates the pump 14. As a result, the air in the intake passage 3 is sucked into the pump 14 through the second port 8 and the second passage portion 11b and discharged to the canister side in the second passage portion 11b, so that the desorbed fuel from the canister 12 is the first. The intake passage 3 is forcibly purged through the port 6.

  According to the third embodiment, the second passage portion 11b of the purge passage 11 is opened before the first passage portion 11a of the purge passage 11 prior to the purge of the evaporated fuel. Therefore, when the upstream pressure of the intake passage 3 is lower than the purge passage 11, the situation where the upstream pressure acts on the first passage portion 11a and the adsorbed fuel of the canister 12 leaks to the first passage portion 11a is avoided. it can. Therefore, it is possible to prevent an unintended purge that is not based on the flow rate control of the pump 14 from being caused by the leaked fuel to the first passage portion 11a.

(Fourth embodiment)
As shown in FIG. 5, in the purge control process according to the fourth embodiment of the present invention, S41 and S45 to S47 having the same contents as S11 and S13 to S15 of the first embodiment are performed, while S12 of the first embodiment is performed. S42 to S44 are performed instead of.
Specifically, in S42, the ECU 27 activates the pump 14. In subsequent S43, the ECU 27 controls the first on-off valve 22 to open the first passage portion 11a of the purge passage 11. Further in S44, the ECU 27 controls the second on-off valve 24 to open the second passage portion 11b of the purge passage 11.

According to the fourth embodiment, the pump 14 is started before the first passage portion 11a of the purge passage 11 is opened prior to the purge of the evaporated fuel. Thereby, since the purge to the intake passage 3 is started simultaneously with the opening of the first passage portion 11a, the target purge flow rate can be achieved quickly. Further, according to the fourth embodiment, the passage portions 11a and 11b of the purge passage 11 are opened in the same order as in the second embodiment prior to the purge of the evaporated fuel, so that the canister 12 to the second passage portion 11b Fuel leakage can be avoided.
In the fourth embodiment, the execution order of S43 and S44 may be reversed. In this case, before purging the evaporated fuel, the passage portions 11a and 11b of the purge passage 11 are opened in the same order as in the third embodiment, so that unintended purging can be prevented.

(Fifth and sixth embodiments)
As shown in FIG. 6, in the fifth embodiment of the present invention, the pump 100 is disposed between the canister 12 and the first on-off valve 22 in the first passage portion 11 a of the purge passage 11. Thereby, since the pump 100 is closer to the first port 6 than in the case of the pump 14 of the first embodiment, the control response of the purge flow rate is improved.

  As shown in FIG. 7, in the sixth embodiment of the present invention, the pump 120 is disposed between the first on-off valve 22 and the first port 6 in the first passage portion 11 a of the purge passage 11. Thereby, since the pump 120 is closer to the first port 6 than in the case of the pump 100 of the fifth embodiment, the control response of the purge flow rate is further enhanced.

(Seventh and eighth embodiments)
As shown in FIG. 8, in the seventh embodiment of the present invention, the pump 140 is disposed between the connection portion to which the atmospheric passage 25 is connected and the second opening / closing valve 24 in the second passage portion 11 b of the purge passage 11. . Thereby, since the pump 140 is farther from the canister 12 than in the case of the pump 14 of the first embodiment, the effect of preventing deterioration inside the pump is enhanced.
As shown in FIG. 9, in the eighth embodiment of the present invention, a pump 160 is disposed between the second opening / closing valve 24 and the second port 8 in the second passage portion 11 b of the purge passage 11. Thereby, since the pump 160 is farther from the canister 12 than in the case of the pump 14 of the seventh embodiment, the effect of preventing deterioration inside the pump is further enhanced.

(Ninth embodiment)
As shown in FIG. 10, in the ninth embodiment of the present invention, instead of the second on-off valve 24 comprising the on / off valve of the first embodiment, a second on-off valve 200 comprising an electromagnetically driven switching valve is provided. Yes.
Specifically, the second on-off valve 200 is arranged at a connection portion to which the atmospheric passage 25 is connected in the second passage portion 11 b of the purge passage 11. The second on-off valve 200 has a first state in which the second passage portion 11b is closed and the atmospheric passage 25 is opened by a movement of a valve member (not shown), and a second state in which the second passage portion 11b is opened and the atmospheric passage 25 is closed. Switch to. Therefore, when the second on-off valve 200 is in the first state, the purge passage 11 and the canister 12 are opened to the atmosphere. On the other hand, when the second on-off valve 200 is in the second state, the pressure of the second passage portion 11 b changes according to the upstream pressure of the intake passage 3.

In such a purge control process of the ninth embodiment, as shown in FIG. 11, S52 having contents similar to S13 of the first embodiment is performed, while S51 is performed instead of S11 and S12 of the first embodiment, and S53 is implemented instead of S14 and 15 of 1st embodiment.
Specifically, at the start of the purge control process, the first opening / closing valve 22 closes the first passage portion 11a of the purge passage 11, the second opening / closing valve 200 is in the first state, and the pump 14 Is in a stopped state.

  In S51, the ECU 27 controls the first on-off valve 22 to open the first passage portion 11a of the purge passage 11, and the ECU 27 switches the second on-off valve 200 to control the second passage portion 11b of the purge passage 11. A second state in which the air passage 25 is open and the air passage 25 is closed is realized. At the same time, in S51, the ECU 27 activates the pump 14. As a result, the air in the intake passage 3 is sucked into the pump 14 through the second port 8 and the second passage portion 11b and discharged to the canister side in the second passage portion 11b, so that the desorbed fuel from the canister 12 is the first. The intake passage 3 is forcibly purged through the port 6.

  In S53, which is started when the purge stop condition is satisfied during the forced purge, the ECU 27 controls the first on-off valve 22 to close the first passage portion 11a of the purge passage 11, and the ECU 27 turns on the second on-off valve 200. By switching control, the first state in which the second passage portion 11b of the purge passage 11 is closed and the atmospheric passage 25 is opened is realized.

  According to the ninth embodiment described above, since the pumps 14 are started at the same time as the passages 11a and 11b are opened prior to the purge of the evaporated fuel, the target purge flow rate can be achieved quickly, and the pump 14 Purge that does not depend on the flow rate control can be prevented. Further, according to the ninth embodiment, since the atmospheric passage 25 is closed when the evaporated fuel is purged, it is possible to prevent air from being introduced into the intake passage 3 from other than the intake passage 3. Furthermore, since the second on-off valve 200 of the ninth embodiment performs the functions of the two on-off valves 24 and 26 in the first embodiment at the same time, the number of parts can be reduced and the cost can be reduced.

  As shown in FIG. 12, in the ninth embodiment, in accordance with the fifth embodiment, the pump 100 disposed between the canister 12 and the first on-off valve 22 in the first passage portion 11a of the purge passage 11 is You may employ | adopt instead of the pump 14. FIG. As shown in FIG. 13, in the ninth embodiment, the pump 120 disposed between the first on-off valve 22 and the first port 6 in the first passage portion 11 a of the purge passage 11 according to the sixth embodiment. May be used instead of the pump 14. Furthermore, as shown in FIG. 14, in the ninth embodiment, according to the eighth embodiment, a pump disposed between the second on-off valve 200 and the second port 8 in the second passage portion 11 b of the purge passage 11. 160 may be used instead of the pump 14.

(Tenth embodiment)
The tenth embodiment of the present invention performs the purge control process with substantially the same configuration as the ninth embodiment shown in FIG. 10, but the purge control process as shown in FIG. While implementing S64 and 65 of contents equivalent to S52 and S53, S61 to S63 are implemented instead of S51 of the ninth embodiment.
Specifically, in S61, the ECU 27 switches and controls the second on-off valve 200 to realize a second state in which the second passage portion 11b of the purge passage 11 is open and the atmospheric passage 25 is closed. In subsequent S62, the ECU 27 controls the first on-off valve 22 to open the first passage portion 11a of the purge passage 11. Further in S63, the ECU 27 activates the pump 14.

According to the tenth embodiment, since the second passage portion 11b of the purge passage 11 is opened before the first passage portion 11a of the purge passage 11 prior to the purge of evaporative fuel, an unintended purge is performed. Can be prevented. Further, according to the tenth embodiment, the atmospheric passage 25 is closed simultaneously with the closing of the second passage portion 11b prior to the opening of the first passage portion 11a and the purge of the evaporated fuel. The introduction into the intake passage 3 can be reliably prevented.
In the tenth embodiment, the execution order of S62 and S63 may be reversed. In this case, prior to the purge of the evaporated fuel, the pump 14 is started before the first passage portion 11a of the purge passage 11 is opened, so that the target purge flow rate can be achieved quickly.

(Eleventh embodiment)
As shown in FIG. 16, in the eleventh embodiment of the present invention, the first on-off valve 250 and the second on-off valve 252 have a common valve member 254 and an electromagnetic drive unit 256. Accordingly, in the purge control process S12 and the like, the ECU 27 controls the energization of the electromagnetic drive unit 256, thereby opening the first passage portion 11a and the second passage portion 11b of the purge passage 11 as shown in FIG. The valve member 254 moves to the first switching position. On the other hand, in S14 and the like of the purge control process, the ECU 27 controls the energization to the electromagnetic drive unit 256, so that the first passage portion 11a and the second passage portion 11b of the purge passage 11 are respectively set as shown in FIG. The valve member 254 moves to the closed second switching position.
As described above, according to the eleventh embodiment, the functions of the two on-off valves 250 and 252 can be realized by the operation of the common valve member 254 and the electromagnetic driving unit 256, so that the cost can be reduced.

  As shown in FIG. 18, according to the eleventh embodiment, the pump 100 disposed between the canister 12 and the first on-off valve 250 in the first passage portion 11a of the purge passage 11 is provided in accordance with the fifth embodiment. The pump 14 may be used instead. As shown in FIG. 19, in the eleventh embodiment, in accordance with the sixth embodiment, a pump disposed between the first on-off valve 250 and the first port 6 in the first passage portion 11 a of the purge passage 11. 120 may be employed instead of the pump 14. Furthermore, as shown in FIG. 20, in the eleventh embodiment, according to the seventh embodiment, between the connection portion connected to the atmospheric passage 25 in the second passage portion 11 b of the purge passage 11 and the second on-off valve 252. The pump 140 arranged in the above may be used instead of the pump 14. In addition, as shown in FIG. 21, in the eleventh embodiment, the second passage portion 11 b of the purge passage 11 is disposed between the second opening / closing valve 252 and the second port 8 according to the eighth embodiment. The pump 160 may be employed instead of the pump 14.

(Twelfth embodiment)
As shown in FIG. 22, in the twelfth embodiment of the present invention, a first port 302 and a second port 304 are provided downstream of the throttle valve 4 in the intake passage 300 of the internal combustion engine, and the ports 302 and 304 are purged. The passage portions 11a and 11b of the passage 11 are connected to each other. Therefore, when the first on-off valve 22 opens the first passage portion 11a, the pressure of the first passage portion 11a changes according to the pressure on the downstream side of the throttle valve 4 in the intake passage 3 (hereinafter simply referred to as the downstream pressure). To do. Further, when the second opening / closing valve 24 opens the second passage portion 11 b, the pressure of the second passage portion 11 b changes according to the downstream pressure of the intake passage 3. In the twelfth embodiment as well, the first port 302 is disposed on the downstream side of the second port 304 to prevent the purge fuel from flowing back.

  In the twelfth embodiment, an electromagnetically driven internal pressure regulating valve 312 is further disposed in the tank passage 310 that connects the fuel tank 2 and the canister 12. The internal pressure adjusting valve 312 adjusts the pressure in the fuel tank 2 by changing the opening of the tank passage 310 according to the control of the ECU 27 electrically connected thereto. As the internal pressure adjusting valve 312, for example, an on / off valve whose opening degree is a binary value of 0% and 100% may be used, and the opening degree changes continuously or discretely between 0% and 100%. A duty control valve may be used.

In such a purge control process of the twelfth embodiment, as shown in FIG. 23, S72 to S75 having contents similar to S12 to S15 of the first embodiment are performed, while S71 is replaced instead of S11 of the first embodiment. carry out.
Specifically, in S71, the ECU 27 controls the third on-off valve 26 to close the atmospheric passage 25, and at the same time controls the internal pressure adjustment valve 312 to set the opening of the tank passage 310 to 0%, that is, the tank passage 310. Close. Note that the closing timing of the atmospheric passage 25 and the closing timing of the tank passage 310 may be moved back and forth with each other, not simultaneously.

  According to the twelfth embodiment described above, the purge passage 11 is opened on both sides of the pump 14 by performing S72 prior to the purge of the evaporated fuel. As a result, in the purge passage 11, the pressure on the suction side of the pump 14 and the pressure on the discharge side of the pump 14 fluctuate by substantially the same amount as the downstream pressure of the intake passage 300. Therefore, even if the pressure on the downstream side of the intake passage 300 fluctuates greatly according to the operating condition of the internal combustion engine, the differential pressure generated between the suction side and the discharge side of the pump 14 in the purge passage 11 is less likely to fluctuate. The NQ characteristic of the pump 14 is stabilized.

  Further, according to the twelfth embodiment, the tank passage 310 is closed prior to the purge of the evaporated fuel. Therefore, even when the pressure on the downstream side of the intake passage 300, that is, the negative pressure acts on the purge passage 11 and the canister 12 during the purge, the negative pressure action does not reach the fuel tank 2. Therefore, the pressure | voltage resistance request | requirement with respect to the fuel tank 2 to which the processing apparatus 10 is applied can be lowered | hung.

(Thirteenth embodiment)
As shown in FIG. 24, the thirteenth embodiment of the present invention is applied to a throttleless internal combustion engine in which the throttle valve 4 of the first embodiment is not present in the intake passage 350.
Specifically, in the thirteenth embodiment, the first passage portion 11a and the second passage portion 11b of the purge passage 11 are respectively connected to the first port 352 and the second port 354 provided at predetermined positions in the intake passage 350. Yes. Therefore, when the first on-off valve 22 opens the first passage portion 11a, the pressure of the first passage portion 11a changes according to the pressure of the intake passage 3. Further, when the second opening / closing valve 24 opens the second passage portion 11 b, the pressure of the second passage portion 11 b changes according to the pressure of the intake passage 3. In the thirteenth embodiment as well, the first port 352 is disposed on the downstream side of the second port 354 to prevent the purge fuel from flowing back.

  In the thirteenth embodiment, purge control processes S11 to S15 according to the first embodiment are performed. Here, according to the execution of S 12, the purge passage 11 is opened on both sides of the pump 14, and therefore, in the purge passage 11, the pressure on the suction side of the pump 14 and the pressure on the discharge side of the pump 14 are in the intake passage 350. Depending on the variation, they vary by approximately the same amount. Therefore, even if the pressure in the intake passage 350 fluctuates according to the operating condition of the internal combustion engine, the pressure difference generated between the suction side and the discharge side of the pump 14 in the purge passage 11 is difficult to fluctuate. NQ characteristics are stabilized.

Although a plurality of embodiments of the present invention have been described above, the present invention is not construed as being limited to these embodiments, and can be applied to various embodiments without departing from the scope of the present invention.
For example, in the first to thirteenth embodiments, positive displacement pumps whose NQ characteristics are relatively stable are used as the pumps 14, 100, 120, 140, and 160, but other types of pumps are used. May be. Further, the characteristic portions of the second to tenth embodiments may be realized in place of the corresponding portions of the eleventh and twelfth embodiments.

It is a block diagram which shows the evaporative fuel processing apparatus by 1st embodiment of this invention. It is a flowchart which shows the action | operation of the evaporative fuel processing apparatus of FIG. It is a flowchart which shows the action | operation of the evaporative fuel processing apparatus by 2nd embodiment of this invention. It is a flowchart which shows the action | operation of the evaporative fuel processing apparatus by 3rd embodiment of this invention. It is a flowchart which shows the action | operation of the evaporative fuel processing apparatus by 4th embodiment of this invention. It is a block diagram which shows the evaporative fuel processing apparatus by 5th embodiment of this invention. It is a block diagram which shows the evaporative fuel processing apparatus by 6th embodiment of this invention. It is a block diagram which shows the evaporative fuel processing apparatus by 7th embodiment of this invention. It is a block diagram which shows the evaporative fuel processing apparatus by 8th embodiment of this invention. It is a block diagram which shows the evaporative fuel processing apparatus by 9th embodiment of this invention. It is a flowchart which shows the action | operation of the evaporative fuel processing apparatus of FIG. It is a block diagram which shows the modification of the evaporative fuel processing apparatus of FIG. It is a block diagram which shows the modification of the evaporative fuel processing apparatus of FIG. It is a block diagram which shows the modification of the evaporative fuel processing apparatus of FIG. It is a flowchart which shows the action | operation of the evaporative fuel processing apparatus by 10th embodiment of this invention. It is a block diagram which shows the evaporative fuel processing apparatus by 11th embodiment of this invention. It is a block diagram which shows the operation state different from FIG. 16 of the evaporative fuel processing apparatus of FIG. It is a block diagram which shows the modification of the evaporative fuel processing apparatus of FIG. It is a block diagram which shows the modification of the evaporative fuel processing apparatus of FIG. It is a block diagram which shows the modification of the evaporative fuel processing apparatus of FIG. It is a block diagram which shows the modification of the evaporative fuel processing apparatus of FIG. It is a block diagram which shows the evaporative fuel processing apparatus by 12th embodiment of this invention. It is a flowchart which shows the action | operation of the evaporative fuel processing apparatus of FIG. It is a block diagram which shows the evaporative fuel processing apparatus by 13th embodiment of this invention. FIG. 6 is a characteristic diagram showing the correlation between the pump rotation speed and the pump flow rate for each differential pressure between the suction side and the discharge side of the pump.

Explanation of symbols

2 Fuel tank, 3, 300 Intake passage, 4 Throttle valve, 6, 302, 352 First port, 8, 304, 354 Second port, 10 Evaporative fuel treatment device, 11 Purge passage, 11a First passage (purge passage) ), 11b Second passage portion (purge passage), 12 canister, 14, 100, 120, 140, 160 pump, 20, 310 tank passage, 22, 250 first on-off valve, 24, 200, 252 second on-off valve, 25 atmospheric passage, 26 third on-off valve, 254 valve member, 312 internal pressure regulating valve

Claims (19)

An evaporative fuel processing device for purging evaporative fuel generated in a fuel tank to an internal combustion engine having a first port and a second port upstream or downstream of a throttle valve in an intake passage,
A purge passage having one end connected to the first port and the other end connected to the second port;
A pump that is disposed in the purge passage and discharges the fluid sucked from the second port side to the first port side in the purge passage;
A canister disposed in the purge passage and removably adsorbing the evaporated fuel generated in the fuel tank;
A first on-off valve that opens and closes the purge passage on the first port side of the canister, the first on-off valve opening the purge passage during a purge period for purging evaporated fuel to the intake passage;
A second on-off valve for opening and closing the purge passage on the second port side of the canister, the second on-off valve opening the purge passage during the purge period;
An atmospheric passage having one end opened to the atmosphere and the other end connected between the canister and the second on-off valve in the purge passage;
An evaporative fuel processing apparatus, comprising: a third on-off valve disposed in the atmospheric passage and configured to open and close the atmospheric passage, wherein the third on-off valve closes the atmospheric passage during the purge period. An evaporative fuel processing device for purging evaporative fuel generated in a fuel tank to an internal combustion engine having a first port and a second port upstream or downstream of a throttle valve in an intake passage,
A purge passage having one end connected to the first port and the other end connected to the second port;
A pump that is disposed in the purge passage and discharges the fluid sucked from the second port side to the first port side in the purge passage;
A canister disposed in the purge passage and removably adsorbing the evaporated fuel generated in the fuel tank;
A first on-off valve that opens and closes the purge passage on the first port side of the canister, the first on-off valve opening the purge passage during a purge period for purging evaporated fuel to the intake passage;
A second on-off valve for opening and closing the purge passage on the second port side of the canister, the second on-off valve opening the purge passage during the purge period;
One end is opened to the atmosphere, and the other end is connected to the second port side of the canister in the purge passage,
The second on-off valve is disposed at a connection portion of the purge passage with the atmospheric passage, and is a first state in which the purge passage is closed and the atmospheric passage is opened, and the purge passage is opened and the atmospheric passage is closed. The evaporative fuel processing apparatus, wherein the second on-off valve is switched to a second state, and is switched to the second state during the purge period. An evaporative fuel processing apparatus for purging evaporative fuel generated in a fuel tank to a throttleless internal combustion engine having a first port and a second port in an intake passage,
A purge passage having one end connected to the first port and the other end connected to the second port;
A pump that is disposed in the purge passage and discharges the fluid sucked from the second port side to the first port side in the purge passage;
A canister disposed in the purge passage and removably adsorbing the evaporated fuel generated in the fuel tank;
A first on-off valve that opens and closes the purge passage on the first port side of the canister, the first on-off valve opening the purge passage during a purge period for purging evaporated fuel to the intake passage;
A second on-off valve for opening and closing the purge passage on the second port side of the canister, the second on-off valve opening the purge passage during the purge period;
An atmospheric passage having one end opened to the atmosphere and the other end connected between the canister and the second on-off valve in the purge passage;
An evaporative fuel processing apparatus, comprising: a third on-off valve disposed in the atmospheric passage and opening and closing the atmospheric passage, wherein the third on-off valve closes the atmospheric passage during the purge period. An evaporative fuel processing apparatus for purging evaporative fuel generated in a fuel tank to a throttleless internal combustion engine having a first port and a second port in an intake passage,
A purge passage having one end connected to the first port and the other end connected to the second port;
A pump that is disposed in the purge passage and discharges the fluid sucked from the second port side to the first port side in the purge passage;
A canister disposed in the purge passage and removably adsorbing the evaporated fuel generated in the fuel tank;
A first on-off valve that opens and closes the purge passage on the first port side of the canister, the first on-off valve opening the purge passage during a purge period for purging evaporated fuel to the intake passage;
A second on-off valve for opening and closing the purge passage on the second port side of the canister, the second on-off valve opening the purge passage during the purge period;
One end is opened to the atmosphere, and the other end is connected to the second port side of the canister in the purge passage,
The second on-off valve is disposed at a connection portion of the purge passage with the atmospheric passage, and is a first state in which the purge passage is closed and the atmospheric passage is opened, and the purge passage is opened and the atmospheric passage is closed. The evaporative fuel processing apparatus, wherein the second on-off valve is switched to a second state, and is switched to the second state during the purge period.
The purge passage, the evaporated fuel of claim 1, or 2, characterized in that it is connected in the intake passage to said first port and said second port being disposed upstream of the throttle valve Processing equipment. The purge passage, the evaporative fuel processing apparatus according to any one of claims 1 to 5, characterized in that connected to the first ports disposed on the downstream side of the second port in the intake passage . A first on-off valve that opens and closes the purge passage on the first port side of the canister, the first on-off valve opening the purge passage during a purge period for purging evaporated fuel to the intake passage;
A second on-off valve for opening and closing the purge passage on the second port side of the canister, the second on-off valve opening the purge passage during the purge period;
The evaporative fuel processing apparatus according to claim 5 , further comprising: In the purge period, after the first shut-off valve is opened the purge passage, claims 1 to 4, wherein the second shut-off valve is characterized in that opening the purge passage, according to any one of 7 Evaporative fuel processing device. In the purge period, after the second shut-off valve is opened the purge passage, claims 1 to 4, wherein the first shut-off valve is characterized in that opening the purge passage, according to any one of 7 Evaporative fuel processing device. Wherein the purge period, after the pump is started, the fuel vapor processing apparatus according to any one of claims 1-4, 7-9, wherein the first shut-off valve is characterized in that opening the purge passage. In the purge period, claims 1 to 4, wherein the first shut-off valve and said second shut-off valve is the opening the purge passage at the same time the pump respectively, characterized in that the start, according to any one of 7 Evaporative fuel processing device. The first on-off valve and the second on-off valve have a common valve member,
By moving the valve member to the first switching position, the purge passage is opened on the first port side and the second port side of the canister,
By the valve member moves to the second switching position, 1-4 wherein the purge passage is characterized in that it is closed at said second port side to the first port side of the canister, 7, 11 any The evaporative fuel processing apparatus of Claim 1. An atmospheric passage having one end opened to the atmosphere and the other end connected between the canister and the second on-off valve in the purge passage;
A third on-off valve disposed in the atmospheric passage for opening and closing the atmospheric passage, the third on-off valve closing the atmospheric passage during the purge period;
The evaporative fuel processing apparatus according to any one of claims 1 to 4, 7 to 12 . In the purge period, after the third on-off valve is closed said air passage, claim 1, 3, 1 3, wherein the first shut-off valve and said second shut-off valve is characterized in that opening the purge passage, respectively The evaporative fuel processing apparatus as described in any one of these. An atmospheric passage having one end open to the atmosphere and the other end connected to the second port side of the canister in the purge passage;
The purge passage is disposed at a connection portion of the purge passage with the atmospheric passage, and is switched to a first state in which the purge passage is closed and the atmospheric passage is opened, and a second state in which the purge passage is opened and the atmospheric passage is closed. A second on-off valve that switches to the second state during the purge period;
The evaporative fuel processing apparatus according to any one of claims 1 to 4, and 7 to 12 . In the purge period, after the second shut-off valve is switched to the second state, in any one of claims 2,4,15, wherein the first shut-off valve is characterized in that opening the purge passage The evaporative fuel processing apparatus of description. The evaporative fuel processing apparatus according to any one of claims 1 to 16 , wherein the pump is disposed on the first port side of the canister in the purge passage. The pump, fuel vapor processing apparatus according to any one of claims 1 to 1 6, characterized in that disposed in the second port side of the canister in the purge passage. The evaporative fuel processing apparatus according to any one of claims 1 to 18 , wherein the pump is a positive displacement pump.

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