JP6531659B2 - Purge device - Google Patents

Description

  The present invention relates to a purge device which collects evaporated fuel generated in a fuel tank in a canister and introduces purge gas containing the collected evaporated fuel from the canister into an intake passage of an internal combustion engine.

  An internal combustion engine mounted on an automobile or the like is provided with a purge device which collects evaporative fuel generated in a fuel tank in a canister and introduces (purges) purge gas including the collected evaporative fuel from the canister into an intake passage. There is. In an internal combustion engine equipped with such a purge device, by introducing a purge gas into the intake passage during engine operation, the evaporated fuel desorbed from the inside of the canister is burned in the combustion chamber of the internal combustion engine and the canister captures the evaporated fuel. Collective ability will be restored.

  Further, the purge device described in Patent Document 1 is mounted on an internal combustion engine provided with a supercharger, and includes a purge passage connected upstream of a compressor in an intake passage from a canister. Then, in the purge device described in Patent Document 1, when supercharging is performed by the compressor, the purge gas is introduced into the intake passage via the purge passage by using the negative pressure generated upstream of the compressor.

Unexamined-Japanese-Patent No. 2006-348901

  By the way, in the purge device, there is a possibility that the passage end of the purge passage connected with the intake passage may come out of the intake passage, and it is necessary to suitably detect the detachment of the passage end of the purge passage. However, in the purge passage for introducing the purge gas into the intake passage upstream of the compressor during supercharging, the inside of the purge passage is in the case where the passage end is connected to the intake passage and in the case where the passage end is detached from the intake passage. The change in pressure etc. is small, making it difficult to detect the end of the passage end.

  The present invention has been made in view of the above situation, and an object thereof is to preferably detect that the passage end of the purge passage connected upstream of the compressor in the intake passage is separated from the intake passage. It is to provide a purge device.

  A purge device for solving the above-mentioned problems is mounted on an internal combustion engine equipped with a supercharger, a canister for collecting evaporated fuel generated in a fuel tank, and extending from the canister upstream of a compressor in an intake passage of the internal combustion engine And a purge pump provided in the middle of the purge passage, the purge gas containing the evaporated fuel collected in the canister is introduced into the intake passage through the purge passage during supercharging by the supercharger. It is a thing. The purge device is provided at a connection portion of the intake passage with the purge passage, and is provided in a switching valve capable of switching between communication and non-communication between the purge passage and the intake passage, and provided in the canister or purge passage to detect internal pressure. When the change of the detection value by the sensor at the time of driving the switching valve so as to switch the communication state between the purge passage and the intake passage while driving the purge pump is less than a predetermined value, And a control device that determines that the passage end of the purge passage is out of the intake passage.

  When the switching passage brings the purge passage and the intake passage into communication while the purge pump is operating, the purge gas is introduced from the canister through the purge passage to the upstream of the compressor in the intake passage. The internal pressure of the purge passage is lower than the atmospheric pressure. On the other hand, if the switching valve disconnects the purge passage from the intake passage while the purge pump is operating, no purge gas is introduced upstream of the compressor in the intake passage as described above. The internal pressure of the purge passage further upstream is higher than that in the communication state.

  Further, in the purge passage downstream of the purge pump, while in the communicating state, the purge gas discharged from the purge pump is introduced into the intake passage, and in the non-communicating state, the purge gas to the intake passage as described above. Since the purge gas is not introduced, the internal pressure is increased when the communication state is switched to the non-communication state. On the contrary, the internal pressure decreases when the communication state is switched from the communication state.

Thus, the internal pressure of the canister or the purge passage when the purge pump is driven changes in accordance with the change of the state of the switching valve.
For this reason, when the passage end of the purge passage is not separated from the intake passage, the internal pressure of the canister or purge passage increases to some extent if the switching valve switches the communication between the purge passage and the intake passage while the purge pump is operating. Change. On the other hand, when the passage end of the purge passage is out of the intake passage, the passage end of the purge passage is out of the switching valve provided in the intake passage. For this reason, even if the switching valve is driven to switch the communication state between the purge passage and the intake passage during driving of the purge pump, the internal pressure of the canister or the purge passage does not change so much.

  Therefore, in the above configuration, the passage end of the purge passage deviates from the intake passage when the change in the detection value by the sensor when the switching valve is driven to switch the communication state during driving of the purge pump is less than a predetermined value. It is determined that the For this reason, if the passage end of the purge passage is not separated from the intake passage, it is detected that a large change in internal pressure is not detected in a state where a large change in internal pressure should be detected by the sensor. Thus, it can be determined that the passage end of the purge passage is out of the intake passage.

  As described above, according to the above configuration, it is possible to preferably detect that the passage end of the purge passage is out of the intake passage.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram which shows the internal combustion engine by which the purge apparatus of embodiment and the purge apparatus are mounted. The flowchart which shows the execution procedure of the determination processing which the control device concerning the embodiment performs.

Hereinafter, an embodiment of the purge device will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, in the intake passage 11 of the internal combustion engine 10 in which the purge device 30 is mounted, the air cleaner 12, the compressor 15 of the supercharger 14, the intercooler 18, and the throttle valve 20 sequentially from the intake upstream side. Is provided. The exhaust passage 21 of the internal combustion engine 10 is provided with a turbine 16 of a turbocharger 14.

  The purge device 30 introduces a canister 32 provided with an adsorbent such as activated carbon for collecting evaporated fuel generated in the fuel tank 29 and a purge gas including the evaporated fuel collected in the canister 32 into the intake passage 11. A passage 40 is provided. The fuel tank 29 and the canister 32 are connected via the passage 31.

  The purge passage 40 extends from the canister 32 and is connected upstream of the compressor 15 in the intake passage 11. Further, a branch passage 45 is connected in the middle of the purge passage 40. That is, the purge passage 40 is composed of the upstream passage 41 from the canister 32 to the branch point 44 and the downstream passage 42 from the branch point 44 to the connecting portion with the intake passage 11. Further, the branch passage 45 is connected downstream of the throttle valve 20 in the intake passage 11.

  In the middle of the upstream passage 41, a purge pump 51 driven to flow the purge gas from the upstream passage 41 to the intake passage 11 via the downstream passage 42 and the branch passage 45 is provided. Further, a flow control valve 52 whose opening degree is controlled to adjust the flow rate of the purge gas flowing from the upstream passage 41 to the downstream passage 42 or the branch passage 45 is provided downstream of the purge pump 51 of the upstream passage 41. There is.

  The downstream passage 42 is provided with a one-way valve 53 that allows only the flow of the purge gas from the branch point 44 to the connection point with the intake passage 11 and does not allow the flow in the opposite direction. Similarly, the branch passage 45 is also provided with a one-way valve 54 that allows only the flow of the purge gas from the branch point 44 to the connection point with the intake passage 11 and does not allow the flow in the opposite direction.

  The main body 32a of the canister 32 is provided with an air communication passage 33 capable of releasing the air in the main body 32a to the outside and taking in the external air into the main body 32a. An internal pressure sensor 71 is provided in the atmosphere communication passage 33 as a sensor for detecting the internal pressure P of the atmosphere communication passage 33. In the present embodiment, the canister 32 is configured including the main body 32 a of the canister 32, the atmosphere communication passage 33, and the connection portion of the main body 32 a with the passage 31 and the purge passage 40. That is, the internal pressure sensor 71 is a sensor that detects the internal pressure in the canister 32.

  A switching valve 72 capable of switching between communication and non-communication between the downstream passage 42 and the intake passage 11 is provided at a connection portion of the intake passage 11 with the downstream passage 42. The switching valve 72 is integrally formed with the intake passage 11 at a connection portion of the intake passage 11 with the downstream passage 42.

  In the purge device 30, the drive of the purge pump 51, the flow rate adjustment valve 52, and the switching valve 72 is controlled by the controller 80. That is, the purge device 30 is configured to include the purge pump 51, the flow rate adjustment valve 52, and the control device 80 that controls the switching valve 72. The control device 80 also serves as a control device that executes various types of engine operation control of the internal combustion engine 10. The control device 80 is provided with a CPU that executes various arithmetic processing related to various types of operation control of the internal combustion engine 10 including control of the purge pump 51, the flow rate adjustment valve 52, and the switching valve 72. In addition, the control device 80 is also provided with a ROM in which programs and data necessary for various operation control are stored, a RAM in which calculation results of a CPU, and the like are temporarily stored. The switching valve 72 and the like are connected to the control device 80.

  Various sensors such as an internal pressure sensor 71 are connected to the control device 80. And control device 80 grasps engine operation states, such as engine revolving speed and engine load, based on signals from various sensors etc. which were connected. Then, the switching valve 72 and the like are controlled based on the recognized engine operating state. In this way, various engine operation control such as opening / closing control of the waste gate valve as well as flow rate control of the purge gas introduced into the intake passage 11 are implemented through the control device 80.

  While the operation of the internal combustion engine 10 is stopped, the drive of the purge pump 51 is stopped and the flow control valve 52 and the switching valve 72 are closed. The mixture of evaporated fuel and air generated in the fuel tank 29 is introduced into the canister 32 through the passage 31. The evaporative fuel in the air-fuel mixture introduced into the canister 32 is collected by the adsorbent of the canister 32 and the air after the evaporative fuel is removed from the air-fuel mixture is sent from the air communication passage 33 of the canister 32 to the canister 32. It is released outside.

  On the other hand, during the operation of the internal combustion engine 10, the purge pump 51 is driven under the condition that the purge execution conditions such as completion of learning of the air fuel ratio feedback correction coefficient for a plurality of learning regions of the internal combustion engine 10 are satisfied. At the same time, the flow control valve 52 and the switching valve 72 are opened. As a result, the evaporative fuel is desorbed from the adsorbent of the canister 32 by the air flowing into the canister 32 through the atmosphere communication passage 33, and the purge gas containing the desorbed evaporative fuel is introduced into the intake passage 11. Become.

  Note that the flow path of the purge gas differs depending on whether or not the supercharger 14 performs supercharging. During supercharging by the supercharger 14, purge gas is introduced into the intake passage 11 via the purge passage 40. During supercharging by the supercharger 14, the pressure downstream of the compressor 15 in the intake passage 11 becomes high. Therefore, even if the flow adjustment valve 52 is opened and the purge pump 51 is driven, the one-way valve 54 is closed, and the purge gas is not introduced from the branch passage 45. On the other hand, even during supercharging, the pressure upstream of the compressor 15 in the intake passage 11 is equivalent to the atmospheric pressure, so the one-way valve 53 is opened and the purge gas is introduced into the intake passage 11 via the downstream passage 42 Ru.

  Further, when the supercharging by the supercharger 14 is not performed, a negative pressure is generated downstream of the throttle valve 20, so the one-way valve 54 is opened and the purge gas is supplied via the upstream passage 41 and the branch passage 45. It is introduced into the intake passage 11.

The evaporated fuel in the purge gas introduced into the intake passage 11 is treated by being burned in the combustion chamber of the internal combustion engine 10.
Further, the control device 80 of the purge device 30 determines whether or not the passage end of the purge passage 40 connected to the intake passage 11, that is, the passage end 42a of the downstream passage 42 is separated from the intake passage 11. Do. This determination process is repeatedly performed at predetermined intervals during engine operation.

  As shown in FIG. 2, when this determination process is started, it is first determined whether supercharging by the supercharger 14 is in progress (step S110). Note that whether or not supercharging is being performed can be determined, for example, according to whether or not the waste gate valve is closed. That is, when the waste gate valve is open, the turbine 16 is bypassed to flow the exhaust, so it can be determined that the supercharging is not being performed, and when the waste gate valve is closed, the exhaust is Since the turbine 16 has been passed, it can be determined that supercharging is in progress. If it is determined that supercharging is being performed (step S110: YES), it is determined whether the above-described purge execution condition is satisfied (step S120). On the other hand, if it is determined that the vehicle is not supercharged (step S110: NO), this process is temporarily ended. In addition, even when it is determined that the above-described purge execution condition is not satisfied (step S120: NO), the present process is temporarily ended.

  When it is determined that the above-described purge execution condition is satisfied (step S120: YES), the switching valve 72 is switched from the valve opening state to the valve closing state (step S130). Here, the switching valve 72 which is in the valve opening state with the satisfaction of the purge execution condition is in the valve closing state. By changing the open state of the switching valve 72, the downstream passage 42 and the intake passage 11 are switched from the communication state to the non-communication state.

  Then, it is determined whether or not the difference between the internal pressure P of the air communication passage 33, which is a detected value by the internal pressure sensor 71 before and after switching by the switching valve 72, is a predetermined value Pa or more (step S140). In the present embodiment, a change in internal pressure when the switching valve 72 is driven to switch the communication state between the purge passage 40 and the intake passage 11 by determining whether the above difference is the predetermined value Pa or more. Is determined to be equal to or greater than a predetermined value, and it is determined whether the passage end 42a of the downstream passage 42 is out of the intake passage 11 based on the result.

  Specifically, in step S140, immediately before execution of step S130, that is, when the downstream passage 42 and the intake passage 11 are in a communicating state, the internal pressure Pf of the atmosphere communication passage 33 indicates that (step S140 is executed). The internal pressure of the air communication passage 33 when the downstream passage 42 and the intake passage 11 are not in communication with each other when the internal pressure Pn of the downstream passage 42 and the intake passage 11 is disconnected. It is determined whether or not it is.

  When it is determined that the difference between the internal pressure P of the air communication passage 33 before and after switching by the switching valve 72 is equal to or greater than the predetermined value Pa (step S140: YES), that is, switching is made to switch the communication state. If the change in internal pressure when the valve 72 is driven is equal to or greater than a predetermined value, it is determined that the passage end 42a of the downstream passage 42 has not been removed from the intake passage 11 (step S150). On the other hand, if it is determined that the difference between the internal pressure P of the air communication passage 33 before and after switching by the switching valve 72 is less than the predetermined value Pa (step S140: NO), that is, switching is made to switch the communication state. When the change in internal pressure when the valve 72 is driven is less than the predetermined value, it is determined that the passage end 42a of the downstream passage 42 is out of the intake passage 11 (step S160). Thus, when it is determined that the passage end 42a of the downstream passage 42 is out of the intake passage 11, the warning light is lit and the driver is informed that the purge passage 40 is out of the intake passage 11 Be done. The predetermined value Pa is set to a value that can determine that the passage end 42a of the downstream passage 42 is out of the intake passage 11 when the absolute value of the difference between the internal pressure Pf and the internal pressure Pn is less than the predetermined value Pa. It is a value preset by an experiment or the like.

When one of the processes of step S150 and step S160 is performed, the switching valve 72 is returned from the closed state to the open state (step S170), and the present process is temporarily ended.
Next, the operation and effects of the present embodiment will be described.

  When the downstream passage 42 and the intake passage are brought into communication by the switching valve 72 while the purge pump 51 is driven, the purge gas is introduced from the canister 32 upstream of the compressor 15 in the intake passage 11 via the purge passage 40. The internal pressure of the canister 32 is lower than the atmospheric pressure. On the other hand, when the purge passage 40 and the intake passage 11 are brought out of communication by the switching valve 72 while the purge pump 51 is driven, the purge gas is not introduced upstream of the compressor 15 in the intake passage 11 as described above. Therefore, the internal pressure of the canister 32 becomes higher than that in the communication state.

  Therefore, when the passage end 42a of the downstream passage 42 is not separated from the intake passage 11, the canister 32 can be switched when the communication valve between the downstream passage 42 and the intake passage 11 is switched by the switching valve 72 while the purge pump 51 is operating. Changes the internal pressure to a certain extent. On the other hand, when the passage end 42 a of the downstream passage 42 is out of the intake passage 11, the passage end 42 a of the downstream passage 42 is out of the switching valve 72 provided in the intake passage 11. Therefore, even if the switching valve 72 is driven to switch the communication state between the downstream passage 42 and the intake passage 11 while the purge pump 51 is driven, the internal pressure of the canister 32 does not change so much.

  Therefore, in the present embodiment, the difference in internal pressure P when the switching valve 72 is driven to switch the communication state during driving of the purge pump 51 is less than the predetermined value Pa, and the change in internal pressure P is less than the predetermined value. In this case, it is determined that the passage end 42 a of the downstream passage 42 is out of the intake passage 11. For this reason, if the passage end 42a of the downstream passage 42 is not out of the intake passage 11, the internal pressure P should be equal to or higher than the predetermined value Pa in a state where a difference (change) in the internal pressure P should be detected by the internal pressure sensor 71. It can be suitably determined that the passage end 42a of the downstream passage 42 is out of the intake passage 11 based on the result of detection.

In addition, the above-mentioned embodiment can also be changed and implemented as follows.
The disposition position of the purge pump 51 may be changed to the downstream passage 42. Even in such a mode, the purge gas can be introduced into the intake passage 11 through the downstream passage 42 by driving the purge pump 51, so that the determination process can be performed as in the above-described embodiment. When the supercharging by the supercharger 14 is not performed, the one-way valve 54 is opened by the negative pressure generated downstream of the throttle valve 20 of the intake passage 11, and the purge gas is sucked into the intake passage 11 through the branch passage 45. Therefore, even if the purge pump 51 is not provided in the upstream passage 41, the purge gas can be introduced into the intake passage 11.

  The arrangement position of the internal pressure sensor 71 can be freely changed between the canister 32 and the purge passage 40. That is, the disposition position of the internal pressure sensor 71 may be a connection portion of the main body 32 a of the canister 32 with the purge passage 40, or may be in the middle of the upstream passage 41 or the downstream passage 42. Also in this embodiment, the predetermined value Pa used for the determination of the removal of the passage end of the purge passage 40 from the intake passage 11 may be set to an appropriate value according to the arrangement position of the internal pressure sensor 71 as in the above embodiment. It is possible to perform the determination process on

  If it can be determined whether or not the change in internal pressure at the time of driving the switching valve 72 so as to switch the communication state between the purge passage 40 and the intake passage 11 is a predetermined value or more, the determination in FIG. The content of step S140 of the process can be changed as appropriate. For example, it may be determined whether the ratio between the internal pressure Pf and the internal pressure Pn is equal to or greater than a predetermined value.

  -By increasing the discharge amount of the purge pump 51, the one-way valve 53 is opened while introducing the purge gas into the intake passage 11 via the branch passage 45 when the supercharger 14 is not performing supercharging. Then, the purge gas can be introduced into the intake passage 11 via the downstream passage 42. In this embodiment, if it is possible to increase the discharge amount of the purge pump 51 to such an extent that the passage end 42a of the downstream passage 42 can be detected out of the intake passage 11, step S110 of the determination process of FIG. Good.

  The switching valve 72 is opened and closed several times while the purge pump 51 is driven, and the removal end of the purge passage 40 is determined from the intake passage 11 based on the magnitude of the change in the internal pressure P during that time. Good. For example, the removal end of the purge passage 40 from the intake passage 11 may be determined based on the magnitude of the change in the internal pressure P during switching from the communication state to the non-communication state and from the non-communication state to the communication state. The determination may be made based on the average value, the maximum value, and the minimum value of the change in the internal pressure P during the repetition of opening and closing twice or more.

  The branch passage 45 may be omitted, and the purge gas may be introduced into the intake passage 11 only from the portion of the intake passage 11 upstream of the compressor 15.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Intake passage, 14 ... Supercharger, 15 ... Compressor, 29 ... Fuel tank, 30 ... Purge apparatus, 32 ... Canister, 32a ... Main body, 33 ... Atmospheric communication passage, 40 ... Purge passage, 41 ... upstream passage, 42 ... downstream passage, 42a ... passage end, 51 ... purge pump, 71 ... internal pressure sensor, 72 ... switching valve, 80 ... control device.

Claims (1)

Mounted on an internal combustion engine equipped with a turbocharger,
A canister for collecting evaporated fuel generated in the fuel tank;
A purge passage extending from the canister and connected upstream of a compressor in an intake passage of the internal combustion engine;
And a purge pump provided in the middle of the purge passage,
A purge device for introducing a purge gas containing evaporated fuel collected in the canister into the intake passage through the purge passage during supercharging by the supercharger,
A switching valve which is provided at a connecting portion of the intake passage to the purge passage, and which can switch communication and non-communication between the purge passage and the intake passage;
A sensor provided in the canister or the purge passage to detect an internal pressure;
When the switching valve is driven to switch the communication state between the purge passage and the intake passage from communication to disconnection while the purge pump is in operation and during supercharging of the supercharger, the detection value of the sensor A control device that determines that the passage end of the purge passage, which has been connected to the intake passage, is out of the intake passage when the change is less than a predetermined value. .

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