Pump apparatus, system having the same, and method for operating the same

Abstract

A pump apparatus includes a housing. A rotor is eccentrically accommodated in the housing. A motor rotates the rotor in the housing. A vane is substantially radially movable relative to the rotor. The vane has a radially outer end that is slidable relative to an inner circumferential periphery of the housing as the rotor and the vane rotates for increasing or decreasing pressure of gas. A pressure sensor detects pressure of the gas. A control unit that evaluates whether an adherence abnormality, in which the vane adheres to the rotor, occurs in accordance with both a detection signal of the pressure sensor and electricity supplied to the motor when the motor rotates the rotor. When the control unit determines the adherence abnormality to be caused, the control unit operates the motor to remove the vane from the rotor.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and incorporates herein by reference Japanese Patent Application No. 2006-39180 filed on Feb. 16, 2006.

FIELD OF THE INVENTION

The present invention relates to a pump apparatus, a system having the same, and a method for operating the same.

BACKGROUND OF THE INVENTION

For example, according to U.S. Pat. No. 6,604,407 (JP-A-2002-364465), a leak check system detects leakage in an evaporator system through which fuel vapor is purged from a fuel tank into an intake passage. In this system, a pump decreases or increases pressure in the evaporator system, so that a leak check operation is conducted in accordance with pressure in the evaporator system. A vane type pump may be used for decreasing or increasing pressure of gas. The vane pump includes a housing that eccentrically accommodates a rotor. The rotor has vanes that are radially movable in the rotor. The rotor rotates, thereby generating centrifugal force, so that the centrifugal force is applied to the vanes. Thus, the vanes slide along the inner circumferential periphery of the housing while being urged onto the inner circumferential periphery of the housing. The vanes decrease or increase pressure of gas while radially reciprocating in the rotor.

In this vane type pump, dew condensation may occur between the rotor and the vanes in dependence upon ambient temperature and moisture, for example. When the vanes adhere to the rotor due to dew condensation, the vanes cannot radially extend outwardly from the rotor by being applied with the centrifugal force. Accordingly, the vanes cannot slide on the inner circumferential periphery of the housing. In this condition, the vane type pump cannot sufficiently decrease or increase pressure of gas.

SUMMARY OF THE INVENTION

The present invention addresses the above disadvantage. According to one aspect of the present invention, a pump apparatus includes a housing. The pump apparatus further includes a rotor that is eccentrically accommodated in the housing. The pump apparatus further includes a motor for rotating the rotor. The pump apparatus further includes a vane that is substantially radially movable relative to the rotor. The vane has a radially outer end that is slidable relative to an inner circumferential periphery of the housing as both the rotor and the vane rotate for increasing or decreasing pressure of gas. The pump apparatus further includes a pressure sensor that detects pressure of the gas. The pump apparatus further includes a control unit that evaluates whether an adherence abnormality, in which the vane adheres to the rotor, occurs, in accordance with both a detection signal of the pressure sensor and electricity supplied to the motor when the motor rotates the rotor. When the control unit determines the adherence abnormality to be caused, the control unit operates the motor to remove the vane from the rotor.

According to another aspect of the present invention, a leak check system for an evaporator system, which is adapted to purging fuel vapor from a fuel tank into an intake passage of an internal combustion engine, the leak check system includes the above pump apparatus for decreasing or increasing pressure in the evaporator system. The leak check system further includes a reference orifice for detecting reference pressure used for evaluating whether leakage occurs in the evaporator system. The leak check system further includes an evaluating unit that evaluates whether leakage occurs in the evaporator system by comparing pressure detected using the pressure sensor with the reference pressure when the pump apparatus decreases or increases pressure in the evaporator system. The control unit evaluates whether the adherence abnormality occurs in accordance with both a detection signal of the pressure sensor and electricity supplied to the motor when detecting the reference pressure.

According to another aspect of the present invention, a method, which is for operating a pump apparatus, includes supplying electricity to a motor for rotating a rotor and radially extending a vane from the rotor by centrifugal force for increasing or decreasing pressure of gas. The method further includes detecting pressure of the gas. The method further includes evaluating whether the vane adheres to the rotor in accordance with both the pressure of the gas and the electricity supplied to the motor. The method further includes operating the motor to remove the vane from the rotor when determining the vane to be adhering to the rotor.

According to another aspect of the present invention, a method for operating a system, which is substantially enclosed, includes operating a switching valve to communicate a pump with the system through a reference orifice. The method further includes supplying electricity to a motor of a pump for rotating a rotor and radially extending a vane from the rotor by centrifugal force for increasing or decreasing pressure of gas in the system through the reference orifice. The method further includes detecting pressure of the gas. The method further includes evaluating whether both the pump and the switching valve are normal, in accordance with both the pressure of the gas and the electricity supplied to the motor when detecting the pressure of the gas. The method further includes operating the switching valve to communicate the pump directly with the system when both the pump and the switching valve are determined to be normal. The method further includes evaluating whether leakage occurs in the system by comparing a time trend of the pressure of the gas with a predetermined time trend.

According to another aspect of the present invention, a method for operating a system, which is substantially enclosed, includes operating a switching valve to communicate a pump with the system through a reference orifice. The method further includes supplying electricity to a motor of a pump for rotating a rotor and radially extending a vane from the rotor by centrifugal force for increasing or decreasing pressure of gas in the system through the reference orifice. The method further includes detecting pressure of the gas. The method further includes evaluating whether both the pump and the switching valve are normal in accordance with both the pressure of the gas and the electricity supplied to the motor when detecting the pressure of the gas. The method further includes determining the vane to be adhering to the rotor when pressure of the gas is abnormal and electricity supplied to the motor is equal to or greater than predetermined threshold. The method further includes determining the switching valve to be abnormal when pressure of the gas is abnormal and when electricity supplied to the motor is less than predetermined threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:

FIG. 1 is a schematic view showing a leak check system;

FIG. 2 is a sectional view showing a pump module of the leak check system;

FIG. 3 is a time chart showing change in pressure in a leak check operation;

FIG. 4 is a time chart showing change in pressure and a motor current in a normal condition;

FIG. 5 is a time chart showing change in pressure and a motor current in an abnormal condition;

FIG. 6 is a time chart showing change in pressure and a motor current in an abnormal condition in which dew condensation is caused; and

FIG. 7 is a flowchart showing the leak check operation.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Example Embodiment

As shown in FIG. 1, a fuel tank 10 connects with a canister 12 through a passage 200. The canister 12 connects with an intake passage 16 through a purge passage 202. The purge passage 202 is provided with a purge valve 14. Fuel evaporates in the fuel tank 10, and the fuel becomes fuel vapor. The fuel vapor passes from the fuel tank 10 into the canister 12 through the passage 200, so that the fuel vapor is absorbed into an absorbent such as activated charcoal provided in the canister 12. The purge valve 14 is actuated using a solenoid device, for example. An amount of fuel vapor, which is purged from the canister 12 into the intake passage 16, is adjusted by controlling the purge valve 14.

In this embodiment, a leak check system includes a pump module 20 and an electronic control unit (ECU) 100. The ECU 100 serves as both a control unit and an evaluating unit. The leak check system conducts a leak check operation for checking leakage caused in an evaporator system. The evaporator system is constructed of the fuel tank 10, the canister 12, the purge valve 14, the passage 200, and the purge passage 202.

The canister 12 has an atmospheric port that connects with a switching valve 30 of the pump module 20 through an atmospheric passage 204. The atmospheric port of the canister 12 connects with a pump 60 of the pump module 20 through a detection passage 206 that branches from the atmospheric passage 204. The pump 60 is a vane type pump that includes multiple vanes, for example. The detection passage 206 is provided with a reference orifice 52a.

The pump module 20 is constructed by integrating the switching valve 30 and the pump 60 to be an integrated module. The pump module 20 and the ECU 100 construct a pump apparatus. The switching valve 30 of the pump module 20 is operated using a solenoid device, for example.

The switching valve 30 includes a coil 36. The switching valve 30 communicates the atmospheric passage 204 with an atmospheric passage 208 when electricity supply to the coil 36 is terminated. The atmospheric passage 208 has an end, which is provided with a filter 92, on the opposite side of the switching valve 30. When electricity is supplied to the coil 36, the canister 12 communicates directly with the pump 60 through the atmospheric passage 204 by substantially bypassing the detection passage 206.

Next, the pump module 20 is described in detail.

The pump module 20 has the atmospheric passages 204, 208, and the detection passage 206. The atmospheric passage 204 regularly communicates with the detection passage 206.

As shown in FIGS. 1, 2, a canister port 50 of the pump module 20 defines part of the detection passage 206. The canister port 50 is provided with a cup member 52 that defines the reference orifice 52a.

The reference orifice 52a is used when the pump 60 decreases pressure in the evaporator system for evaluating pressure at which the interior in the evaporator system reaches. The reference orifice 52a is used for evaluating a hole in the evaporator system.

Filters 54 are provided to upstream and downstream of the reference orifice 52a.

The switching valve 30 of the pump module 20 is actuated using a solenoid device. The switching valve 30 includes a movable core 34 that is opposed to a stationary core 32. The movable core 34 is provided with a shaft 40 to which valve members 42, 43 are provided. The valve members 42, 43 are formed of rubber, for example. The valve members 42, 43 are axially depart from each other. As shown in FIG. 2, when electricity supply to the coil 36 is terminated, the valve member 42 blocks the canister port 50, and the valve member 43 communicates an atmospheric port 56. In this condition, the atmospheric passage 204 communicates with the atmospheric passage 208, and the detection passage 206 communicates with the atmospheric passage 208 through the atmospheric passage 204. When electricity is supplied to the coil 36, the stationary core 32 and the movable core 34 generate magnetic attractive force therebetween, so that the movable core 34 moves toward the stationary core 32 upwardly in FIG. 2. In this condition, the valve member 42 communicates the canister port 50, and the valve member 43 blocks the atmospheric port 56. In this condition, the atmospheric passage 204 communicates directly with the pump 60 by substantially bypassing the detection passage 206, and the atmospheric passage 204 is blocked from the atmospheric passage 208.

The pump 60 of the pump module 20 is a vane type pump including an electric motor 62 for rotating a rotor 70. The pump 60 includes the rotor 70, vanes 72, and a housing 74 that are formed of resin, for example. For example, the rotor 70 has four slits that are arranged circumferentially at regular intervals. Each of the four slits radially extends in the rotor 70. Each of the vanes 72 is in a substantially plate shape. Each vane 72 is radially movable in each slit of the rotor 70. The housing 74 is in a substantially annular shape. The housing 74 accommodates the rotor 70. The rotor 70 is eccentric with respect to the housing 74. The rotor 70 is rotatable relative to the housing 74. The motor 62 rotates the rotor 70, which is eccentric with respect to the housing 74, so that centrifugal force is applied radially outwardly to each vane 72. Each vane 72 radially reciprocates while sliding relative to the inner circumferential periphery of the housing 74 along the inner circumferential periphery of the housing 74. The pump 60 has an inlet port 80 that is provided with a filter 82. A pressure sensor 90 detects pressure in the vicinity of the inlet port 80 of the pump 60. In this structure of the pump 60, the rotor 70 rotates, and each vane 72 radially reciprocates, so that either the atmospheric passage 204 or the detection passage 206 is reduced in pressure.

The ECU 100 includes a CPU, a ROM, an I/O interface, and the like. The CPU of the ECU 100 executes a control program stored in the ROM, so that the ECU 100 controls driving signals for operating the switching valve 30 and the motor 62 of the pump 60 of the pump module 20. In addition, the ECU 100 inputs pressure detection signal P from the pressure sensor 90.

As follows, an operation of the leak check operation is described.

First, in the period A shown in FIG. 3, the ECU 100 detects atmospheric pressure Patm in accordance with the detection signal P of the pressure sensor 90 in a condition where the ECU 100 terminates electricity supply to the switching valve 30 and the motor 62 of the pump 60. For example, when the vehicle is in a high altitude location and the detection pressure P of the pressure sensor 90 is less than predetermined pressure, the ECU 100 may not conduct the leak check operation. The atmospheric pressure Patm detected using the pressure sensor 90 may be used as a correction value for evaluating pressure in the following leak check operation.

Second, as shown in FIG. 7, in step 300, the ECU 100 supplies electricity to the motor 62 to start the operation of the pump 60 in the condition in which the ECU 100 terminates electricity supply to the switching valve 30, as referred to FIG. 1. In this condition, the pump 60 communicates with the atmosphere through the detection passage 206, the atmospheric passage 204, the switching valve 30, the atmospheric passage 208, and the filter 92. The routine proceeds to step 302 of FIG. 7, in which the ECU 100 detects reference pressure Pref using the pressure sensor 90 when the pump 60 is operated in the period B in FIG. 3. The reference pressure Pref is determined in dependence upon the passage area corresponding to the inner diameter of the reference orifice 52a.

Third, in step 304 of FIG. 7, the ECU 100 evaluates the reference pressure Pref detected using the pressure sensor 90. As shown in FIG. 4, when the ECU 100 determines the reference pressure Pref to be within a normal pressure range P1, the routine proceeds to step 306, in which the ECU 100 supplies electricity to the switching valve 30 to operate the switching valve 30. When the ECU 100 supplies electricity to the switching valve 30, the switching valve 30 communicates the pump 60 directly with the atmospheric passage 204 in the vicinity of the canister 12, and substantially blocks the atmospheric passage 204 from the atmospheric passage 208.

In step 308, the ECU 100 checks leakage pressure. Specifically, the ECU 100 operates the pump 60 to reduce pressure in the evaporator system constructed of the fuel tank 10, the canister 12, the purge valve 14, the passage 200, and the purge passage 202, so that the ECU 100 evaluates leakage in the evaporator system in accordance with a time trend of the detection pressure P.

In step 308, the ECU 100 compares the time trend of the detection pressure P of the pressure sensor 90 with a curve 220 in FIG. 3, so that the ECU 100 evaluates whether leakage occurs in the evaporator system due to a hole greater than the passage area in the reference orifice 52a. A curve 222 in the period C of FIG. 3 depicts a time trend of the pressure in the evaporator system when the evaporator system has a hole, which is equal to the passage area in the reference orifice 52a. For example, as depicted by the curve 222, when the detection pressure P of the pressure sensor 90 is less than the curve 220, the ECU 100 determines that the evaporator system causes a leakage through a hole less than the reference orifice 52a. In this case, the detection pressure P in the evaporator system quickly decreases by the pump 60, so that the ECU 100 determines that leakage in the evaporator system is small.

By contrast, for example, as depicted by the curve 224, when the detection pressure P of the pressure sensor 90 is greater than the curve 220, the ECU 100 determines that the evaporator system causes a leakage through a hole greater than the passage area in the reference orifice 52a. In this case, the detection pressure P in the evaporator system slowly decreases even the pump 60 draws gas from the evaporator system, consequently, the ECU 100 determines that leakage in the evaporator system is large.

Fourth, in step 304, when the reference pressure Pref is greater than the normal pressure range P1, as shown in FIGS. 5, 6, the ECU 100 determines an abnormality to be caused. In this case, the routine proceeds to step 310, in which ECU 100 detects a motor current E, which corresponds to electricity supplied to the motor 62 of the pump 60. Subsequently, the routine proceeds to step 312, in which the ECU 100 evaluates the motor current E. As referred to FIG. 5, when the motor current E is small in a normal electricity range I1, a failure may be caused in a portion excluding the evaporator system. In this condition, for example, failure may be caused in a sealing structure of the switching valve 30, and consequently, load applied to the pump 60 may become small.

Specifically, when electricity supply to the coil 36 of the switching valve 30 is terminated, the valve member 42 may not sufficiently block the canister port 50. In this case, the atmospheric passage 204 may communicate directly with the pump 60 by substantially bypassing the reference orifice 52a. In this condition, the passage area connecting with the pump 60 may become large compared with the reference orifice 52a, and consequently, load applied to the motor 62 of the pump 60 for drawing gas from the evaporator system decreases.

As a result, the motor current E decreases, and the motor current E may be small in the normal electricity range I1. In this case, the switching valve 30 needs a maintenance work such as replacement. Thus, the routine proceeds to step 320, in which the ECU 100 cancels the leak check operation, so that the routine shown in FIG. 7 is terminated.

In this condition, the ECU 100 may generate an alarm for notifying malfunction caused in the switching valve 30, for example.

By contrast, as referred to FIG. 6, when the reference pressure Pref, which corresponds to the detection pressure P of the pressure sensor 90, is greater than the normal pressure range P1, and the motor current E is greater than the normal electricity range I1, the ECU 100 determines a failure to be caused in the pump 60. Specifically, in this case, the ECU 100 determines that the vane 72 adheres to the rotor 70 because of dew condensation or the like. In this condition, the vane 72 cannot radially outwardly move even being applied with the centrifugal force. Consequently, the pump 60 cannot sufficiently reduce pressure in the detection passage 206 through the reference orifice 52a. In this case, the ECU 100 determines the motor 62 to be applied with large load due to surface tension applied between the rotor 70 and the housing 74 because of dew condensation, and consequently, the motor current E is greater than the normal electricity range I1.

Fifth, as referred to FIG. 6, when the ECU 100 determines a failure to be caused by dew condensation in accordance with the reference pressure Pref and the motor current E, the routine proceeds to step 314, in which the ECU 100 supplies electricity to the motor 62 of the pump 60 to operate the pump 60. In this operation, the ECU 100 operates the pump 60, thereby rotating the rotor 70 in a condition excluding a normal timing of the leak check operation. Thus, dew condensation can be removed by, for example, heat generated by sliding the rotor 70 relative to the housing 74. In step 314, the ECU 100 operates the pump 60, and in steps 316, 318, the ECU 100 inputs the detection pressure P of the pressure sensor 90 and evaluates the detection pressure P. The ECU 100 repeats the operation in steps 310, 312, 314, 316, 318 until the detection pressure P becomes within the normal pressure range P1. In this operation, dew condensation in the pump 60 can be removed in a short period by increasing the rotation speed of the motor 62 to be greater than rotation speed in a normal operating condition. In step 318, when the detection pressure P becomes within the normal pressure range P1, the ECU 100 determines the motor current E to be also within the normal electricity range I1, so that the routine proceeds to step 306. In step 306, the ECU 100 checks the leakage pressure in the evaporator system.

In this embodiment, when the reference pressure Pref is out of the normal pressure range P1, the ECU 100 evaluates whether dew condensation is caused in accordance with evaluation of the motor current E. In this operation, the routine can be restricted from proceeding to step 306 in a condition in which the pump 60 cannot sufficiently reduce pressure because the vane 72 adheres to the rotor 70 due to dew condensation. Therefore, the leak check operation can be restricted from being erroneously conducted. In this embodiment, when the reference pressure Pref is out of the normal pressure range P1, the ECU 100 operates the pump 60, thereby removing the dew condensation in a condition excluding the normal timing of the leak check operation. Thus, the ECU 100 can properly conduct the leak check operation after removing the dew condensation.

Other Embodiment

Dew condensation of the pump 60 may be removed by operating the motor 62 for a period longer than a normal period for detecting the reference pressure Pref. Specifically, a timer period may be set longer than a normal timer period, which is set for detecting the reference pressure Pref.

The vane type pump apparatus in this embodiment may be applied to any purposes other than the leak check system, as long as the vane type pump apparatus includes a pump that decreases or increases pressure of gas.

When the vane type pump apparatus in this embodiment is applied to a leak check system, the leak check operation may be conducted by increasing pressure in an evaporator system.

The functions of the units may be produced using a hardware resource having functions specified by a physical construction thereof, a hardware resource having functions specified by a program, or a combination of the hardware resources. The functions of the units are not limited to be produced using hardware resources, which are physically individual from each other.

The number of the vanes 72 is not limited to four. The number of the slits in the rotor 70 is not also limited to four. The numbers of the vanes 72 and corresponding slits of the rotor 70 may be determined as appropriate.

It should be appreciated that while the processes of the embodiments of the present invention have been described herein as including a specific sequence of steps, further alternative embodiments including various other sequences of these steps and/or additional steps not disclosed herein are intended to be within the steps of the present invention.

Various modifications and alternations may be diversely made to the above embodiments without departing from the spirit of the present invention.

Claims

1. A pump apparatus comprising:

a housing;

a rotor that is eccentrically accommodated in the housing;

a motor for rotating the rotor;

a vane that is substantially radially movable relative to the rotor, the vane having a radially outer end that is slidable relative to an inner circumferential periphery of the housing as both the rotor and the vane rotate for increasing or decreasing pressure of gas;

a pressure sensor that detects pressure of the gas; and

a control unit that evaluates whether an adherence abnormality, in which the vane adheres to the rotor, occurs, in accordance with both a detection signal of the pressure sensor and electricity supplied to the motor when the motor rotates the rotor,

wherein when the control unit determines the adherence abnormality to be caused, the control unit operates the motor to remove the vane from the rotor.

2. The pump apparatus according to claim 1,

wherein the control unit determines the adherence abnormality to be caused when both the following two conditions are satisfied:

pressure, indicated by the detection signal of the pressure sensor, is in the vicinity of atmospheric pressure compared with pressure in a normal pressure range; and

electricity supplied to the motor is greater than a normal electricity range.

3. The pump apparatus according to claim 1, wherein when the control unit determines the adherence abnormality to be caused, the control unit increases rotation speed of the motor compared with rotation speed in a normal operating condition.

4. A leak check system for an evaporator system, which is adapted to purging fuel vapor from a fuel tank into an intake passage of an internal combustion engine, the leak check system comprising:

the pump apparatus according to claim 1 for decreasing or increasing pressure in the evaporator system;

a reference orifice for detecting reference pressure used for evaluating whether leakage occurs in the evaporator system; and

an evaluating unit that evaluates whether leakage occurs in the evaporator system by comparing pressure detected using the pressure sensor with the reference pressure when the pump apparatus decreases or increases pressure in the evaporator system,

wherein the control unit evaluates whether the adherence abnormality occurs in accordance with both a detection signal of the pressure sensor and electricity supplied to the motor when detecting the reference pressure.

5. A pump apparatus comprising:

a housing;

a rotor that is accommodated in the housing;

a motor for rotating the rotor;

a vane that is substantially radially extendable relative to the rotor as the motor rotates for increasing or decreasing pressure of gas;

a pressure sensor that detects pressure of the gas; and

a control unit that evaluates whether the vane adheres to the rotor in accordance with both the pressure of the gas and electricity supplied to the motor when the motor rotates the rotor,

wherein when the control unit determines the vane to be adhering to the rotor, the control unit operates the motor-to remove the vane from the rotor.

6. A method for operating a pump apparatus, the method comprising:

supplying electricity to a motor for rotating a rotor and radially extending a vane from the rotor by centrifugal force for increasing or decreasing pressure of gas;

detecting pressure of the gas;

evaluating whether the vane adheres to the rotor in accordance with both the pressure of the gas and the electricity supplied to the motor; and

operating the motor to remove the vane from the rotor when determining the vane to be adhering to the rotor.

7. A method for operating a system, which is substantially enclosed, the method comprising:

operating a switching valve to communicate a pump with the system through a reference orifice;

supplying electricity to a motor of a pump for rotating a rotor and radially extending a vane from the rotor by centrifugal force for increasing or decreasing pressure of gas in the system through the reference orifice;

detecting pressure of the gas;

evaluating whether both the pump and the switching valve are normal, in accordance with both the pressure of the gas and the electricity supplied to the motor when detecting the pressure of the gas;

operating the switching valve to communicate the pump directly with the system when both the pump and the switching valve are determined to be normal; and

evaluating whether leakage occurs in the system by comparing a time trend of the pressure of the gas with a predetermined time trend.

8. A method for operating a system, which is substantially enclosed, the method comprising:

operating a switching valve to communicate a pump with the system through a reference orifice;

supplying electricity to a motor of a pump for rotating a rotor and radially extending a vane from the rotor by centrifugal force for increasing or decreasing pressure of gas in the system through the reference orifice;

detecting pressure of the gas;

evaluating whether both the pump and the switching valve are normal, in accordance with both the pressure of the gas and the electricity supplied to the motor when detecting the pressure of the gas;

determining the vane to be adhering to the rotor when pressure of the gas is abnormal and electricity supplied to the motor is equal to or greater than predetermined threshold; and

determining the switching valve to be abnormal when pressure of the gas is abnormal and when electricity supplied to the motor is less than predetermined threshold.