JP2005048719A - Pump module used for failure diagnosis of evaporated fuel treating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump module used in failure diagnosis of an evaporated fuel treating apparatus, preventing clogging of an orifice to make a failure diagnosis with good accuracy by always disposing the orifice at the top position in its on-vehicle mounted state. <P>SOLUTION: The orifice 33 is disposed between a solenoid part 30 and a valve body part 31 of a selector valve 29 provided on the pump module 20. The selector valve 29 is fitted while being rotated around the Z-axis to a case of the pump module 20, whereby the orifice 23 is disposed at the top corresponding to the on-vehicle mounted state of the pump module 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is used for failure diagnosis of an evaporative fuel processing apparatus in which evaporative fuel generated in a fuel tank is collected by a canister and fuel components in the evaporative fuel collected are purged into an intake passage of an engine and processed. The present invention relates to a pump module to be used. More specifically, the present invention relates to a pump module that can perform failure diagnosis with high accuracy.

  2. Description of the Related Art Conventionally, an evaporative fuel processing apparatus that processes evaporative fuel (vapor) generated in a fuel tank without releasing it into the atmosphere is known as one of apparatuses mounted on a vehicle. This device is equipped with a canister that collects vapor, temporarily adsorbs the vapor to the adsorbent inside the canister, and uses the negative pressure generated in the intake passage when the engine is operating, in the vapor collected in the canister The fuel component (hydrocarbon (HC) or the like) is purged into the intake passage through the purge passage and is processed for combustion in the engine.

  By the way, in this type of processing device, if for some reason a failure occurs such as a leak hole in the middle of the flow path including the canister from the fuel tank to the intake passage, or a seal failure occurs at the pipe joint, The airtightness of the flow path deteriorates. In this case, the vapor generated in the fuel tank cannot be properly processed.

  In order to cope with such a failure, it is necessary to diagnose the failure at an early stage. Several techniques for this type of fault diagnosis have already been proposed. For example, Japanese Patent Application Laid-Open No. 2002-4959 discloses an example of this type of diagnostic apparatus.

  The basic idea of what is disclosed in Japanese Patent Application Laid-Open No. 2002-4959 is that an orifice is provided to measure a reference pressure change (leakage amount) in advance, and then the flow path of the processing apparatus is closed. By making a negative pressure state and comparing the subsequent pressure change with a reference pressure change, the presence or absence of a leak or the like is diagnosed.

Japanese Patent Laid-Open No. 2002-4959 (pages 2 and 3, FIG. 1)

  However, in the above-described Japanese Patent Application Laid-Open No. 2002-4959, the position of the orifice may be arranged below the other flow path depending on the vehicle mounting state. If the orifice is disposed below, the orifice may be clogged with dust, water, adsorbent fine powder, oil in the pipe, plastic extract, assembly oil, or the like. Thus, when the orifice is blocked, there is a problem that failure diagnosis cannot be performed with high accuracy.

  Accordingly, the present invention has been made to solve the above-described problems, and by always arranging the orifice at the top position in the vehicle mounted state, the orifice can be prevented from being blocked and the failure diagnosis can be performed with high accuracy. It is an object of the present invention to provide a pump module used for failure diagnosis of a fuel vapor processing apparatus.

  A pump module used for failure diagnosis of an evaporative fuel processing apparatus according to the present invention, which has been made to solve the above problems, is provided corresponding to an engine mounted on a vehicle and captures evaporative fuel generated in a fuel tank with a canister. Is connected to an evaporative fuel processing device that purges the fuel component in the collected evaporative fuel to the intake passage of the engine, and depressurizes the evaporative fuel processing device, and the behavior of the pressure at that time A pump module used for diagnosing a failure of the evaporated fuel processing apparatus based on the negative pressure pump for making the inside of the evaporated fuel processing apparatus a negative pressure, a connection port connected to the evaporated fuel processing apparatus, and one end Is connected to the connection port, and the other end is connected to the negative pressure pump. An orifice passage provided with an orifice for discharge, pressure detecting means for detecting pressure in the fuel vapor processing apparatus and the orifice passage, and a switching valve for switching communication / blocking between the connection port and the atmospheric port The orifice is arranged in the sky when mounted on a vehicle and is located above the opening / closing portion of the switching valve.

  In the pump module used for failure diagnosis of this fuel vapor processing apparatus, the orifice for calculating the determination value for failure diagnosis is arranged in the sky in the vehicle-mounted state and is located above the opening / closing portion of the switching valve. It is possible to prevent the orifice from being clogged when calculating the determination value for failure diagnosis. This is because dust, water, and the like have a certain weight and fall down due to their own weight. As a result, the determination value of the failure diagnosis can be accurately calculated, so that the accuracy of the failure diagnosis of the evaporated fuel processing apparatus can be improved.

  In the pump module used for failure diagnosis of the fuel vapor processing apparatus according to the present invention, the orifice is provided between an actuator provided in the switching valve and a valve body, and the switching valve is movable of the valve body. It is desirable to be able to mount by rotating around an extension line in the direction.

  By doing so, the pump module can be attached to the vehicle while adjusting the position of the orifice when the vehicle is mounted. Therefore, it is possible to always place the orifice in an up-down direction with respect to an arbitrary vehicle so as to be positioned above the opening / closing portion of the switching valve.

  By configuring a failure diagnosis device for the evaporated fuel processing apparatus using the above-described pump module, the failure diagnosis of the evaporated fuel processing device can be performed with high accuracy.

  According to the pump module used for the failure diagnosis of the evaporated fuel processing apparatus according to the present invention, the orifice is always arranged at the top position in the vehicle mounted state and is positioned above the opening / closing portion of the switching valve. The obstruction of the orifice is prevented when calculating. Thereby, since the determination reference value for failure diagnosis can be accurately measured, failure diagnosis can be performed with high accuracy.

  Hereinafter, a most preferred embodiment in which a pump module used for failure diagnosis of an evaporated fuel processing apparatus of the present invention is embodied will be described in detail with reference to the drawings. 1 and 2 show the schematic configuration of the evaporated fuel processing apparatus and its failure diagnosis apparatus. 1 shows a state in which the switching valve is not energized, and FIG. 2 shows a state in which the switching valve is energized.

  The evaporated fuel processing apparatus 1 according to this embodiment is attached to a vehicle equipped with a gasoline engine, and collects and processes the evaporated fuel (vapor) generated in the fuel tank 10 without releasing it into the atmosphere. Is for. The evaporative fuel processing apparatus 1 includes a canister 12 for collecting vapor generated in the fuel tank 10 through a vapor line 11. The canister 12 has a built-in adsorbent made of activated carbon.

  In addition to the vapor line 11, a purge line 13 is connected to the canister 12, and the purge line 13 communicates with a position downstream of the throttle valve 15 in the intake passage 14. The purge line 13 is provided with a purge control valve 16. Thereby, when the engine of the vehicle is operated, the negative pressure generated in the intake passage 14 acts on the purge line 13. Therefore, when the purge control valve 16 is opened in the evaporated fuel processing apparatus 1, it is collected by the canister 12. The fuel component is purged to the intake passage 14 through the purge line 13 and processed. The purge control valve 16 provided in the purge line 13 is an electromagnetic valve that operates the valve body in response to an electric signal.

  A pump module 20 is connected to the canister 12. The canister 12 collects only the fuel component in the vapor introduced from the fuel tank 10 and discharges only the gas not containing the fuel component to the outside from the atmospheric port 21 formed in the pump module 20. It has become. Note that an air cleaner 22 is connected to the other end of the atmospheric port 21.

  Here, the pump module 20 will be described with reference to FIGS. FIG. 3 is a plan view showing the pump module. 4 is a cross-sectional view taken along line AA in FIG. 5 is a cross-sectional view taken along line BB in FIG.

  As shown in FIG. 3, the pump module 20 is provided with three attachment holes 20 a and is attached to the vehicle side using these attachment holes 20 a. Further, a connector 45 for connecting the pump module 20 and an ECU 40 described later is provided.

  In addition, as shown in FIGS. 4 and 5, the pump module 20 includes an atmospheric port 21 connected to the air cleaner 22, an orifice channel 24 in which an orifice 23 is formed, and a connection port 25 connected to the canister 12. Is formed. Further, the pump module 20 includes a negative pressure pump 26 for reducing the pressure in the evaporated fuel processing device 1, a pressure sensor 27 for measuring the pressure in the fuel treatment device 1 and the orifice channel 24, and a connection port. 25 and a switching valve 29 for switching the communication / blocking state between the atmospheric port 21 and the atmospheric port 21. As a result, the inside of the evaporated fuel processing apparatus 1 in a sealed state can be decompressed by the negative pressure pump 26, and a failure diagnosis of the evaporated fuel processing apparatus 1 can be performed based on the subsequent pressure change.

  The negative pressure pump 26 is a vane pump driven by a DC motor. For this reason, the negative pressure pump 25 can generate a positive pressure by reversing the DC motor. Therefore, it is also possible to pressurize the evaporated fuel processing apparatus 1 in a sealed state and perform failure diagnosis based on the subsequent pressure change. A check valve 28 is provided upstream of the negative pressure pump 26. This check valve 28 stops the flow of gas from the negative pressure pump 26 toward the orifice flow path 24 or the connection port 25.

  The switching valve 29 includes a solenoid (actuator) portion 30 and a valve body portion 31. The solenoid unit 30 is slidably fitted in the magnetic tube 33, a coil 32 in which a copper wire is wound around a hollow coil bobbin 32a, a magnetic tube 33 fitted and fixed in the hollow of the coil bobbin 32a. And a movable iron core 34. On the other hand, the valve body portion 31 includes a diaphragm valve 36, a tapered first valve seat 37a, and a tapered second valve seat 37b.

  The tip of a rod 35 that extends downward from the movable iron core 34 and is slidably supported by the guide member 39 is connected to the diaphragm valve body 36. Thereby, when the solenoid part 30 drives, the diaphragm valve body 36 moves to the up-down direction in the figure. Here, the diaphragm valve body 36 is always urged by a biasing spring 38 from below in the drawing in a direction in which the diaphragm valve body abuts on the first valve seat 37a (separates from the second valve seat 37b). Therefore, when the coil 32 is not energized, the diaphragm valve body 36 contacts the first valve seat 37a and is separated from the second valve seat 37b. At this time, since the first valve seat 37a has a tapered shape, high sealing performance can be obtained. In this state, the atmospheric port 21 and the connection port 25 communicate with each other via the second valve seat 37b (see FIG. 1).

  On the other hand, when the coil 32 is energized, the coil 32 attracts the movable iron core 34, and the attraction force is larger than the urging force of the urging spring 38, so that the movable iron core 34 and the rod 35 move downward in the figure. Along with the movement of the rod 35, the diaphragm valve body 36 is separated from the first valve seat 37a and abuts on the second valve seat 37b (see FIG. 10). At this time, since the second valve seat 37b has a tapered shape, high sealing performance can be obtained. In this state, the atmospheric port 21 and the connection port 25 are blocked, and the connection port 25 and the negative pressure pump 26 communicate directly (see FIG. 2).

  An orifice 23 is provided between the actuator portion 30 and the valve body portion 31 of the switching valve 29. Here, the switching valve 29 can be attached to the case of the pump module 20 while rotating around the Z axis located on the extension line in the movable direction of the diaphragm valve body 36. Therefore, when the pump module 20 is mounted on the vehicle side using the three mounting holes 20a, the orifice 23 is always set regardless of the state of the pump module 20 mounted in the vehicle, as shown in FIG. The switch valve 29 can be positioned above the opening / closing part 37 (the part corresponding to the inner side of the first valve seat 37b) 37. Thereby, since dust, water, adsorbent fine powder, oil in piping, plastic extract, assembly oil, etc. fall downward due to their own weight, the orifice 23 can be prevented from being blocked by these foreign substances. . 6 and 7 show cross sections taken along the line CC of FIG.

  Returning to FIG. 1, a failure diagnosis device for diagnosing a failure related to airtightness of the evaporated fuel processing device 1 by the pump module 20 having the above-described configuration, an electronic control unit (ECU) 40, and a warning lamp 41. 2 is configured. Here, the ECU 40 executes the engine control of the vehicle and the purge control of the evaporated fuel processing apparatus 1 and the like. For example, the ECU 40 is configured to control the purge control valve 16 based on a required drive duty value in order to purge an amount of fuel component suitable for engine operation.

  In addition, the ECU 40 is configured to execute failure diagnosis control related to the airtightness of the evaporated fuel processing apparatus 1. That is, the ECU 40 acquires the detection signal from the pressure sensor 27 by controlling the purge control valve 16, the negative pressure pump 26, and the switching valve 29 as necessary based on detection signals from various sensors. The ECU 40 is configured to diagnose a malfunction related to the airtightness of the evaporated fuel processing apparatus 1 based on the input detection value of the pressure sensor 27. This failure includes a failure related to the airtightness of the fuel tank 10, a failure related to the airtightness of the canister 12, a failure related to the airtightness of the pipe joints of the vapor line 11 and the purge line 13, and the like.

  And the warning lamp 41 provided in the driver's seat of the vehicle operates to notify the driver of the diagnosis result and the like related to the failure. The ECU 40 turns on or blinks the warning lamp 41 when diagnosing a failure, and turns off the warning lamp 41 in other cases.

  As is well known, the ECU 40 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), a backup RAM, an external input circuit, an external output circuit, and the like. The ECU 40 constitutes a logical operation circuit formed by connecting a CPU, a ROM, a RAM, a backup RAM, an external input circuit, an external output circuit, and the like through a bus. The ROM stores in advance a predetermined control program relating to engine control, purge control, failure diagnosis control, and the like. The RAM temporarily stores the calculation result of the CPU. The backup RAM stores data stored in advance. Here, the backup RAM stores the diagnosis result regarding the failure as diagnosis data.

  In addition, an ignition switch 42 and a soak timer 43 are connected to the external input circuit of the ECU 40. The ignition switch 42 is turned on / off to start / stop the engine of the vehicle. The ignition switch 42 allows the power to the ECU 40 to be turned on when the operation is turned on, and cuts off the power supply to the ECU 40 when the operation is turned off. The soak timer 43 starts counting when the ignition switch 42 is turned off, and activates the ECU 40 to start failure diagnosis when the engine is left after being stopped and a predetermined time has elapsed.

  Next, the operation of the failure diagnosis apparatus 2 will be described with reference to FIGS. FIG. 8 is a time chart showing an outline of failure diagnosis. FIG. 9 is a diagram illustrating a gas flow in the pump module 20 when the switching valve 29 is turned on. FIG. 10 is a diagram illustrating a gas flow in the pump module 20 when the switching valve 29 is turned off.

  This failure diagnosis is started from time t0 when the ignition switch 42 is turned off and a predetermined time (several hours) elapses by the time of the soak timer 43. That is, the ECU 40 is activated at time t0. At this time, the switching valve 29 is turned off, and in the pump module 20 as shown in FIG. 9, the connection port 25 and the atmospheric port 21 are communicated, and gas flows as shown by the solid line. Therefore, in this state, the inside of the evaporated fuel processing apparatus 1 is not sealed. Then, the atmospheric pressure is measured by the pressure sensor 27 until the time t1 is reached.

  When the time t2 is reached, the switching valve 29 is turned on, and the amount of evaporated fuel generated from the fuel tank 10 is checked. Specifically, the pressure in the evaporated fuel processing apparatus 1 is measured by the pressure sensor 27 to check the amount of evaporated fuel generated. At this time, when the amount of evaporated fuel generated is large, that is, when the pressure rise is large, the failure diagnosis process is stopped.

  On the other hand, when the failure diagnosis process is continued, at time t3, the switching valve 29 is turned off and the negative pressure pump 26 is driven. As a result, the gas in the pump module 20 flows from the atmospheric port 21 through the orifice 23 to the negative pressure pump 26 as shown by a one-dot broken line in FIG. Finally, the pressure in the orifice channel 24 reaches the saturation pressure at the diameter of the orifice 23 (for example, 0.5 mm). Then, the saturation pressure at that time is measured by the pressure sensor 27. The saturation pressure measured at this time becomes a reference for fault diagnosis.

  Here, in the pump module 20 according to the present embodiment, the orifice 23 can always be arranged above the opening / closing portion 37 of the switching valve 29 regardless of the vehicle mounting state. For this reason, at the time of reference measurement, the orifice 23 is not blocked by dust, water, adsorbent fine powder, pipe oil, plastic extract, assembly oil, or the like. Therefore, an accurate reference can always be measured.

  Then, the switching valve 29 is turned on again at time t3, and a leak check of the evaporated fuel processing device 1 is performed until time t4 is reached. At this time, as shown in FIG. 10, since the atmospheric port 21 and the connection port 25 are blocked, the inside of the evaporated fuel processing apparatus 1 is sealed. Since the gas flows as shown by the solid line in FIG. 10 due to the action of the negative pressure pump 26, the inside of the evaporated fuel device 1 is decompressed. At this time, if there is no failure in the evaporated fuel processing apparatus 1, the pressure in the evaporated fuel processing apparatus 1 is reduced to a value lower than the above-described reference. On the other hand, when a failure occurs in the evaporated fuel processing apparatus 1, the pressure in the evaporated fuel processing apparatus 1 does not decrease to the above-described reference.

  As described above, when a failure occurs, a pressure change different from that in the normal state occurs, so that the failure diagnosis of the evaporated fuel processing apparatus 1 can be performed based on the pressure change. Since the failure diagnosis apparatus 2 according to the present embodiment can always accurately measure a reference serving as a reference for performing failure diagnosis, the failure diagnosis of the evaporated fuel processing apparatus 1 can be performed with high accuracy.

  As described above in detail, in the pump module 20 according to the present embodiment, the orifice 23 is provided between the solenoid portion 30 and the valve body portion 31 of the switching valve 29. The switching valve 29 can be attached to the case of the pump module 20 while rotating around the Z axis. As a result, the orifice 23 can always be arranged in the top direction regardless of the on-vehicle state of the pump module 20, so that the orifice 22 can be prevented from being blocked by dust or water. Therefore, since the reference serving as a reference for failure diagnosis can always be accurately measured, failure diagnosis of the evaporated fuel processing apparatus 1 can be performed with high accuracy.

  It should be noted that the above-described embodiment is merely an example and does not limit the present invention in any way, and various improvements and modifications can be made without departing from the scope of the invention.

It is a figure which shows schematic state of the evaporative fuel processing apparatus which concerns on this Embodiment, and its diagnostic apparatus, and shows the state which is not supplying with electricity to the switching valve. It is a figure which shows the schematic structure of the evaporative fuel processing apparatus which concerns on this Embodiment, and its diagnostic apparatus, and the state which has supplied with electricity to the switching valve. It is a top view which shows schematic structure of a pump module. It is sectional drawing which shows schematic structure of a pump module and shows the cross section in the AA of FIG. It is sectional drawing which shows schematic structure of a pump module and shows the cross section in the BB line of FIG. It is a figure for demonstrating that an orifice is always arrange | positioned in the top direction irrespective of a vehicle-mounted state. Similarly, it is a figure for demonstrating that an orifice is always arrange | positioned in the top direction irrespective of a vehicle-mounted state. It is a time chart which shows the outline | summary of the process of the failure diagnosis in a failure diagnosis apparatus. It is a figure for demonstrating the flow of the gas in the pump module in the state which is not supplying with electricity to the switching valve. It is a figure for demonstrating the flow of the gas in the pump module in the state which energized the switching valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Evaporated fuel processing apparatus 2 Failure diagnosis apparatus 10 Fuel tank 12 Canister 14 Intake passage 20 Pump module 21 Atmospheric port 23 Orifice 24 Orifice flow path 25 Connection port 26 Negative pressure pump 27 Pressure sensor 29 Switching valve 30 Solenoid part 31 Valve body part

Claims (3)

Evaporative fuel processing provided corresponding to an engine mounted on a vehicle, collecting evaporated fuel generated in a fuel tank by a canister, and purging fuel components in the collected evaporated fuel to an intake passage of the engine A pump module that is connected to an apparatus and depressurizes the inside of the evaporated fuel processing apparatus, and is used for diagnosing a failure of the evaporated fuel processing apparatus based on a behavior of pressure at that time,
A negative pressure pump for making the inside of the evaporated fuel processing apparatus negative pressure;
A connection port connected to the evaporative fuel treatment device;
An atmospheric port with one end open to the atmosphere;
One end is connected to the connection port, the other end is connected to the negative pressure pump, and an orifice passage provided with an orifice for calculating a determination value for failure diagnosis in the middle thereof;
Pressure detecting means for detecting pressure in the fuel vapor processing apparatus and in the orifice passage;
A switching valve for switching communication / blocking between the connection port and the atmospheric port;
The pump module used for failure diagnosis of an evaporated fuel processing apparatus, wherein the orifice is arranged in a sky direction in a vehicle-mounted state and is positioned above an opening / closing portion of the switching valve. In the pump module used for failure diagnosis of the evaporated fuel processing apparatus according to claim 1,
The orifice is provided between an actuator and a valve body provided in the switching valve,
A pump module used for failure diagnosis of an evaporative fuel processing device, wherein the switching valve can be mounted by rotating around an extension line in the movable direction of the valve body.   A failure diagnosis apparatus for an evaporative fuel processing apparatus, wherein the pump module according to claim 1 or 2 is used.

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