Fixation prevention device for pump

Abstract

To provide a fixation prevention device for a pump that can prevent fixation of a sliding part of the pump.SOLUTION: A fixation prevention device 90 for a pump comprises: a pump 772 for generating negative pressure; a recovered liquid generation part 91 connected to a fuel tank 80 storing fuel, for cooling evaporated fuel generated in the fuel tank 80, condensing and recovering a low boiling point component of the fuel contained in the evaporated fuel, and generating recovered liquid; a first pipe 92 for establishing communication between a discharge port of the recovered liquid generation part 91 and a recovered liquid suction port 772d of the pump 772; a first opening / closing valve 95 for opening and closing the discharge port of the recovered liquid generation part 91; and a second opening / closing valve 96 for opening and closing the recovered liquid suction port 772d of the pump 772. When a predetermined cleaning control execution condition including an engine stop is established, an ECU 50 opens each of the first opening / closing valve 95 and the second opening / closing valve 96, drives the pump 772, and allows the recovered liquid to be sucked into the pump 772 through the first pipe 92.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an anti-seizure device for a pump that prevents seizure of a sliding part of the pump.

Background Art

[0002] Conventionally, in order to prevent the release of evaporated fuel generated in a fuel tank into the environment (atmosphere), the evaporated fuel is temporarily adsorbed by an adsorbent (such as activated carbon, etc.) in a canister, and the adsorbed evaporated fuel is sucked into the intake system of an engine under predetermined operating conditions and burned for treatment. An evaporative fuel treatment system (evaporative purge system) is widely used.

[0003] By the way, in North American OBD2 (On Board Diagnostics Second Generation), it is required to diagnose the presence or absence of abnormalities in such an evaporative fuel treatment system.

[0004] Therefore, for example, Patent Document 1 discloses an evaporative gas purge system leak diagnosis device (ELCM: Evaporative Leak Check Module) including an electric negative pressure pump, a reference pressure detection unit in which a reference hole (a hole having a predetermined hole diameter corresponding to a minute leak hole) is formed, a path for introducing a negative pressure into the reference pressure detection unit by the negative pressure pump, a passage switching valve (switching valve) for switching between a path for introducing a negative pressure into the evaporative system by the negative pressure pump, and a pressure sensor.

[0005] In this diagnostic device, a negative pressure is introduced into the reference pressure detection unit by the negative pressure pump to detect the pressure in the reference pressure detection unit, that is, the reference pressure regulated by the reference hole. Then, the passage switching valve switches the negative pressure introduction path of the pump, introduces a negative pressure into the evaporative system, detects the pressure in the evaporative system, and compares the reference pressure with the pressure in the evaporative system to determine the presence or absence of a minute leak.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-300997 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] By the way, the sliding part of the negative pressure pump that constitutes the leak diagnosis device (diagnosis device for the evaporative fuel treatment system) of the evaporative gas purge system as described above has high sealing performance. However, if, for example, salt (a compound composed of anions and cations), water, wear powder, etc. enter the sliding part, the operation of the sliding part may be inhibited and sticking may occur. When the sliding part of the negative pressure pump becomes stuck, there is a risk that the diagnosis device of the evaporative fuel treatment system may make a misdiagnosis. Therefore, an invention for preventing the sticking of the pump has been desired.

[0008] The present invention has been made to solve the above problems, and an object thereof is to provide a pump sticking prevention device capable of preventing the sticking of the sliding part of the pump. [Means for Solving the Problems]

[0009] The pump sticking prevention device according to one aspect of the present invention includes a pump that generates a negative pressure, a fuel tank that stores fuel, is connected to the fuel tank, cools the evaporative fuel generated in the fuel tank, condenses and recovers the low-boiling components of the fuel contained in the evaporative fuel, and generates a recovered liquid. A recovered liquid generation unit, a first pipe that communicates the discharge port of the recovered liquid generation unit and the recovered liquid suction port of the pump, a first on-off valve that opens and closes the discharge port of the recovered liquid generation unit, a second on-off valve that opens and closes the recovered liquid suction port of the pump, and a control unit that controls the opening and closing of each of the first on-off valve and the second on-off valve and the driving of the pump. When a predetermined cleaning control execution condition including engine stop is satisfied, the control unit opens each of the first on-off valve and the second on-off valve and drives the pump to suck the recovered liquid into the pump through the first pipe (execute cleaning control).

[0010] According to the pump sticking prevention device according to one aspect of the present invention, first, the evaporated fuel generated in the fuel tank is cooled, the low-boiling components of the fuel contained in the evaporated fuel are condensed and recovered, and a recovered liquid is generated. Then, when predetermined cleaning control execution conditions including engine stop are satisfied, the first on-off valve and the second on-off valve are each opened, the pump is driven, and the recovered liquid is sucked into the pump through the first pipe (cleaning control is executed). Therefore, due to the negative pressure generated by the pump, the recovered liquid composed of low-boiling components of the fuel is sucked into the pump through the first pipe and discharged through the rotating pump. Thus, the recovered liquid can wash away, for example, salts (compounds composed of anions and cations), water, wear powder, etc. that have accumulated in the pump (i.e., can cause pump sticking).

Advantages of the Invention

[0011] According to the present invention, it is possible to prevent sticking of the sliding portion of the pump.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0013] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals. Also, in each figure, the same elements are denoted by the same reference numerals and redundant explanations are omitted. In the present embodiment, the case where the present invention is applied to a diagnostic device for an evaporative fuel processing system will be described as an example.

[0014] First, with reference to FIGS. 1 to 6 together, the configuration of the pump fixing prevention device 90 according to the embodiment and the diagnostic device 77 of the evaporative fuel processing system to which the pump fixing prevention device 90 is applied will be described. FIG. 1 is a diagram showing the configuration of the diagnostic device 77 of the evaporative fuel processing system to which the pump fixing prevention device 90 is applied and the engine 10 including the diagnostic device 77 of the evaporative fuel processing system. FIG. 2 is a cross-sectional view showing the configuration (off state) of the switching valve 771 that constitutes the diagnostic device 77 of the evaporative fuel processing system to which the pump fixing prevention device 90 is applied. Also, FIG. 3 is a cross-sectional view showing the configuration (on state) of the switching valve 771. FIG. 4 is a diagram showing the configuration of the pump fixing prevention device 90. FIG. 5 is a diagram showing the structure of the vane of the pump 772 that constitutes the pump fixing prevention device 90. FIG. 6 is a diagram showing the arrangements of the intake port 772c, the recovered liquid intake port 772d, and the recovered liquid discharge port / exhaust port 772e of the pump 772 that constitutes the pump fixing prevention device 90.

[0015] The engine 10 is, for example, a horizontally opposed four-cylinder gasoline engine. Further, the engine 10 is an in-cylinder injection type engine that directly injects fuel into the cylinder (inside the cylinder). In the engine 10, the air inhaled from the air cleaner 16 is throttled by an electronically controlled throttle valve (hereinafter, also simply referred to as "throttle valve") 13 provided in the intake pipe 15, passes through the intake manifold 11, and is inhaled into each cylinder formed in the engine 10. Here, the amount of air inhaled from the air cleaner 16 (the amount of air inhaled into the engine 10) is detected by an air flow meter 14 disposed between the air cleaner 16 and the throttle valve 13. Further, inside the collector portion (surge tank) constituting the intake manifold 11, a vacuum sensor 30 for detecting the pressure inside the intake manifold 11 (intake manifold pressure) is disposed. Furthermore, a throttle opening sensor 31 for detecting the opening degree of the throttle valve 13 is disposed on the throttle valve 13.

[0016] In the cylinder head, an intake port 22 and an exhaust port 23 are formed for each cylinder (only one bank is shown in FIG. 1). In each of the intake port 22 and the exhaust port 23, an intake valve 24 and an exhaust valve 25 for opening and closing the intake port 22 and the exhaust port 23 are provided. Between the intake camshaft 28 that drives the intake valve 24 and the intake cam pulley, a variable valve timing mechanism 26 is disposed that relatively rotates the intake cam pulley and the intake camshaft 28 to continuously change the rotational phase (displacement angle) of the intake camshaft 28 with respect to the crankshaft 10a, thereby advancing and retarding the valve timing (opening and closing timing) of the intake valve 24. The opening and closing timing of the intake valve 24 is variably set according to the engine operating state by this variable valve timing mechanism 26.

[0017] Similarly, between the exhaust camshaft 29 and the exhaust cam pulley, a variable valve timing mechanism 27 is provided that relatively rotates the exhaust cam pulley and the exhaust camshaft 29 to continuously change the rotational phase (displacement angle) of the exhaust camshaft 29 with respect to the crankshaft 10a, thereby advancing or retarding the valve timing (opening and closing timing) of the exhaust valve 25. The opening and closing timing of the exhaust valve 25 is variably set according to the engine operating state by this variable valve timing mechanism 27.

[0018] An injector 12 for injecting fuel into the cylinder is attached to each cylinder of the engine 10. The injector 12 directly injects the fuel pressurized by the high-pressure fuel pump 60 into the combustion chamber of each cylinder.

[0019] The injector 12 is connected to a delivery pipe (common rail) 61. The delivery pipe 61 distributes the fuel pumped from the high-pressure fuel pump 60 through the fuel pipe 62 to each injector 12. The high-pressure fuel pump 60 boosts the fuel sucked up from the fuel tank 80 by the feed pump (low-pressure fuel pump) 64 to a high pressure (for example, 8 to 13 MPa) according to the operating state and supplies it to the delivery pipe 61. In this embodiment, a high-pressure fuel pump 60 of a type driven by the camshaft 28 of the engine 10 is used.

[0020] An ignition plug 17 for igniting the air-fuel mixture and a coil with built-in igniter 21 for applying a high voltage to the ignition plug 17 are attached to the cylinder head of each cylinder. In each cylinder of the engine 10, the air-fuel mixture of the inhaled air and the fuel injected by the injector 12 is ignited by the ignition plug 17 and burns. The exhaust gas after combustion is discharged through the exhaust pipe 18.

[0021] An air-fuel ratio sensor 19A that outputs a signal according to the oxygen concentration in the exhaust gas is attached to the exhaust pipe 18. As the air-fuel ratio sensor 19A, a linear air-fuel ratio sensor (LAF sensor) that can linearly detect the exhaust air-fuel ratio is used. Note that an O2 sensor that detects the exhaust air-fuel ratio in an on-off manner may be used as the air-fuel ratio sensor 19A.

[0022] Further, an exhaust gas purification catalyst (CAT) 20 is disposed downstream of the air-fuel ratio sensor 19A. The exhaust gas purification catalyst 20 is a three-way catalyst that simultaneously oxidizes hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas and reduces nitrogen oxides (NOx), and purifies harmful gas components in the exhaust gas into harmless carbon dioxide (CO2), water vapor (H2O), and nitrogen (N2). A rear (after CAT) O2 sensor 19B that detects the exhaust air-fuel ratio in an on-off manner is provided downstream of the exhaust gas purification catalyst 20.

[0023] Here, the engine 10 is provided with an evaporative fuel treatment system 70. The evaporative fuel treatment system 70 mainly includes a fuel tank 80, a canister 71, a first purge pipe 72a, a second purge pipe 72b, and a variable flow rate solenoid valve 73.

[0024] The fuel tank 80 stores fuel supplied to the engine 10 (injector 12). The upper space of the fuel tank 80 communicates with a canister 71 that can adsorb the evaporated fuel generated in the fuel tank 80 via the first purge pipe 72a. Here, a recovery liquid generation unit (evaporated fuel recovery unit) 91 is interposed in the first purge pipe 72a. That is, a recovery liquid generation unit 91 is provided between the fuel tank 80 and the canister 71. Details of the recovery liquid generation unit 91 will be described later.

[0025] The canister 71 has an adsorbent such as activated carbon inside, and temporarily adsorbs the evaporated fuel generated in the fuel tank 80 (more specifically, the evaporated fuel generated in the fuel tank 80 and not recovered by the recovery liquid generation unit 91 (mainly high-boiling components)).

[0026] The upper space of the canister 71 communicates with the intake manifold 11 via a second purge pipe 72b (the first purge pipe 72a and the second purge pipe 72b are collectively referred to as the purge pipe 72). A variable flow rate solenoid valve (hereinafter also referred to as a "purge solenoid valve") 73 whose opening degree is adjusted by the ECU 50 is installed in the second purge pipe 72b.

[0027] When the purge solenoid valve 73 opens and the negative pressure in the intake manifold 11 acts on the canister 71, outside air (air) is introduced into the canister 71 through a diagnostic device 77 (details will be described later) of the evaporative fuel processing system, and the evaporative fuel adsorbed on the activated carbon etc. in the canister 71 is desorbed. The desorbed evaporative fuel is inhaled into the intake manifold 11 of the engine 10 through the second purge passage 72b together with the air introduced through the diagnostic device 77 of the evaporative fuel processing system. Then, the evaporative fuel inhaled into the intake manifold 11 is burned and processed in the cylinder of the engine 10.

[0028] A diagnostic device (ELCM (Evaporative Leak Check Module)) 77 of the evaporative fuel processing system is connected to the canister 71. The diagnostic device 77 of the evaporative fuel processing system mainly includes a switching valve 771, a pump 772, an orifice 774, and a pressure sensor 773, and diagnoses the presence or absence of abnormalities (such as leakage of evaporative fuel) in the evaporative fuel processing system 70.

[0029] The switching valve 771, the pump 772, and the orifice 774 are connected to each other by an evaporative passage 775, an atmospheric passage 778, a pump passage 776, and an orifice passage 777. More specifically, one end of the evaporative passage 775 is connected to the canister 71, and the other end is connected to the switching valve 771. That is, the evaporative passage 775 communicates the canister 71 and the switching valve 771.

[0030] The atmosphere passage 778 has one end open to the atmosphere via a filter 779, and the other end connected to the exhaust port 772e of the pump 772 and the switching valve 771 respectively. That is, the atmosphere passage 778 communicates the open end open to the atmosphere with the exhaust port 772e of the pump 772 and the switching valve 771 respectively. The pump passage 776 has one end connected to the intake port 772c of the pump 772, and the other end connected to the switching valve 771. That is, the pump passage 776 communicates the intake port 772c of the pump 772 with the switching valve 771.

[0031] The orifice passage 777 has one end connected to the evap passage 775 and the other end connected to the pump passage 776. That is, the orifice passage 777 communicates the evap passage 775 with the pump passage 776. Further, a reference orifice (reference hole) 774 (hereinafter sometimes simply referred to as "orifice 774") is provided in the orifice passage 777. Note that the reference orifice 774 is set according to the size of the opening allowing leakage (for example, φ0.5 mm).

[0032] The pump 772 is a negative pressure pump (vacuum pump) that generates negative pressure. For the pump 772, for example, an electric vane pump driven by an electric motor or the like is used. The pump 772 (electric motor) is driven (controlled) by an ECU 50 described later.

[0033] More specifically, the pump 772 includes a cam ring having an inner peripheral surface with a circular cross section, a rotor 772f eccentrically disposed inside the cam ring and driven by an electric motor, a pump shaft rotatably supporting the rotor 772f, and a plurality of vanes 772a incorporated in grooves formed around the rotor 772f.

[0034] Each of the plurality of vanes 772a is formed in a substantially rectangular plate shape and is movable in the radial direction of the rotor 772f (retractable). When the rotor 772f rotates, the vane 772a incorporated in the groove of the rotor 772f pops out by centrifugal force, and its tip rotates along the inner side surface of the eccentric cam ring in a state of contacting the inner peripheral surface of the cam ring. At this time, the volume of the pump chamber defined by the cam ring, the rotor 772f, and the adjacent vane 772a changes, and the suction and discharge operations are performed.

[0035] Here, the structure of the vane 772a of the pump 772 (vane pump) is shown in FIG. 5. As shown in FIG. 5, a plurality (three in this embodiment) of grooves (discharge grooves) 772b extending radially outward and obliquely upward of the rotor 772f are formed on the side surface of the vane 772a. The recovery liquid described later is efficiently discharged radially outward through this groove 772b (along the groove 772b).

[0036] Also, the arrangement (positional relationship) of the intake port 772c, the recovery liquid suction port (injection port) 772d, and the recovery liquid discharge port / exhaust port 772e of the pump 772 (vane pump) is shown in FIG. 6. The intake port 772c is formed at a position where the volume of the pump chamber begins to increase. Also, a recovery liquid suction port (injection port) 772d is formed near the intake port 772c. On the other hand, the recovery liquid discharge port 772e and the exhaust port 772e (common) are formed at a position where the volume of the pump chamber begins to decrease.

[0037] With the above configuration, when the electric pump is driven (when the rotor 772f rotates), air (outside air) is inhaled from the intake port 772c, compressed, and discharged (ejected) from the exhaust port 772e. On the other hand, the recovery liquid described later is inhaled from the recovery liquid suction port (injection port) 772d and discharged (ejected) from the recovery liquid discharge port 772e. Here, the exhaust port 772e and the recovery liquid discharge port 772e are common, and the discharged liquid component (recovery liquid) returns to the fuel tank 80 by its own weight through the second pipe 93 described later, and the gas component (gas) is discharged from the air passage 778 (gas-liquid separation structure).

[0038] The switching valve 771 switches between a state in which the evaporation passage 775 and the pump passage 776 communicate with each other (evaporation path) and a state in which the atmosphere passage 778 and the orifice passage 777 communicate with each other (orifice path).

[0039] As shown in FIG. 2, when the switching valve 771 is off (when power supply is stopped), the atmosphere passage 778 and the orifice passage 777 communicate with each other, and the evaporation passage 775 and the pump passage 776 are blocked.

[0040] On the other hand, as shown in FIG. 3, when the switching valve 771 is on (when power is supplied), the evaporation passage 775 and the pump passage 776 communicate with each other, and the atmosphere passage 778 and the orifice passage 777 are blocked. The switching valve 771 is driven (controlled) by the ECU 50.

[0041] Returning to FIG. 1, a pressure sensor 773 is attached to the downstream side of the orifice 774 in the orifice passage 777 (between the orifice 774 and the pump passage 776 (intake port 772c)). The pressure sensor 773 detects the pressure in the evaporation passage 775 (in the evaporation path) when the switching valve 771 is turned on and the pump 772 is driven during diagnosis. Further, the pressure sensor 773 detects the pressure in the orifice passage 777 (in the orifice passage) when the switching valve 771 is turned off and the pump 772 is driven during diagnosis. The pressure sensor 773 is connected to the ECU 50, and an electrical signal (for example, voltage) corresponding to the pressure is read by the ECU 50.

[0042] The diagnostic device 77 of the evaporative fuel processing system includes a pump sticking prevention device 90 that prevents sticking of the sliding part of the pump 772. The pump sticking prevention device 90 mainly includes a recovered liquid generation unit 91, a first pipe 92, a second pipe 93, a filter 94, a first on-off valve 95, a second on-off valve 96, a third on-off valve 97, a fourth on-off valve 98, and an ECU 50.

[0043] As shown in FIG. 4, the recovered liquid generation unit (evaporated fuel recovery unit) 91 is connected to a fuel tank 80 that stores fuel (provided between the fuel tank 80 and the canister 71), cools the evaporated fuel generated in the fuel tank 80, and separates low-boiling components (e.g., hydrocarbon components such as pentane, hexane, benzene, toluene, ethylbenzene, xylene, etc., alcohol-based components such as ethanol, and ether-based components such as methyl tert-butyl ether) and moisture contained in the evaporated fuel, condenses and recovers them, and generates a recovered liquid (hereinafter sometimes referred to as "cleaning liquid").

[0044] The recovered liquid generation unit 91 is formed, for example, in a substantially cylindrical shape or a substantially prismatic shape, and its bottom is configured to be able to store the recovered liquid. Also, a discharge port for discharging the recovered liquid is formed at the lower part.

[0045] As a method for cooling the evaporated fuel, for example, an air-cooling method using cooling fins or a water-cooling method by heat exchange with cooling water is preferably used. For example, in an HEV (hybrid vehicle), etc., cooling water for cooling a high-voltage battery can also be used. Note that the recovery of the evaporated fuel (generation of the recovered liquid) is performed constantly (that is, both when the engine is operating and when the engine is stopped). Also, the evaporated fuel (mainly high-boiling components) that was not recovered in the recovered liquid generation unit 91 is sent to the canister 71, temporarily adsorbed in the canister 71, and then inhaled into the engine 10 and processed (burned). Here, by separating and recovering the low-boiling components and the high-boiling components, the recovery efficiency is improved compared to the case of only a conventional canister.

[0046] The first pipe 92 communicates the discharge port (supply port) formed at the lower part of the recovered liquid generation unit 91 and the recovered liquid suction port (injection port) 772d of the pump 772. When the cleaning control described later is executed, the recovered liquid (cleaning liquid) is inhaled from the recovered liquid generation unit 91 into the pump 772 through the first pipe 92.

[0047] The first on-off valve 95 is provided at the discharge port of the recovered liquid generation unit 91 and opens and closes the discharge port. That is, the first on-off valve 95 interrupts the communication between the recovered liquid generation unit 91 and the first pipe 92. For the first on-off valve 95, for example, an electromagnetic (solenoid) on-off valve is preferably used. The first on-off valve 95 is controlled to be driven (opened and closed) by the ECU 50. The first on-off valve 95 is opened when the cleaning control described later is executed.

[0048] The second on-off valve 96 is provided at the recovered liquid suction port 772d of the pump 772 and opens and closes the recovered liquid suction port 772d. That is, the second on-off valve 96 interrupts the communication between the recovered liquid suction port 772d of the pump 772 and the first pipe 92. For the second on-off valve 96, for example, an electromagnetic (solenoid) on-off valve is preferably used. The second on-off valve 96 is controlled to be driven (opened and closed) by the ECU 50. The second on-off valve 96 is opened when the cleaning control described later is executed.

[0049] The second pipe 93 communicates the recovered liquid discharge port / exhaust port 772e of the pump 772 with the upper part of the fuel tank 80. The second pipe 93 returns the recovered liquid (cleaning liquid) after cleaning discharged (drained) from the pump 772 to the fuel tank 80 (by its own weight). An atmosphere passage 778 for discharging (venting) air and gas components (gases) discharged from the recovered liquid discharge port / exhaust port 772e of the pump 772 is connected to the recovered liquid discharge port / exhaust port 772e side (nearby) of the second pipe 93 of the pump 772.

[0050] The third on-off valve 97 is installed in the second pipe 93 on the downstream side of the connection point with the atmosphere passage 778 and opens and closes the second pipe 93. For the third on-off valve 97, for example, an electromagnetic (solenoid) on-off valve is preferably used. The third on-off valve 97 is controlled to be driven (opened and closed) by the ECU 50. The third on-off valve 97 is opened when the cleaning control described later is executed.

[0051] Further, a filter 94 is interposed downstream of the third on-off valve 97 of the second pipe 93. The filter 94 captures (collects) foreign matters (such as wear powder) contained in the recovered liquid (cleaning liquid) returned to the fuel tank 80 through the second pipe 93.

[0052] The fourth on-off valve 98 is provided at the intake port 772c of the pump 772 and opens and closes the intake port 772c. For the fourth on-off valve 98, for example, an electromagnetic (solenoid type) on-off valve is preferably used. The fourth on-off valve 98 is controlled to be driven (opened and closed) by the ECU 50. The first on-off valve 95 is closed when the cleaning control described later is executed.

[0053] Returning to FIG. 1, in addition to the air flow meter 14, LAF sensor 19A, O2 sensor 19B, vacuum sensor 30, throttle opening sensor 31, and pressure sensor 773 described above, a cam angle sensor 32 for discriminating the cylinders of the engine 10 is attached near the camshaft of the engine 10. Further, a crank angle sensor 33 for detecting the rotational position of the crankshaft 10a is attached near the crankshaft 10a of the engine 10. Here, at the end of the crankshaft 10a, for example, a timing rotor 33a having 34 teeth with two teeth missing is formed at 10° intervals, and the crank angle sensor 33 detects the rotational position of the crankshaft 10a by detecting the presence or absence of the protrusions of the timing rotor 33a. As the cam angle sensor 32 and the crank angle sensor 33, for example, electromagnetic pickup type ones are used.

[0054] These sensors are connected to the ECU 50. Further, various sensors such as a water temperature sensor 34 for detecting the temperature of the cooling water of the engine 10, an oil temperature sensor 35 for detecting the temperature of the lubricating oil, an accelerator opening sensor 36 for detecting the depression amount of the accelerator pedal, that is, the opening (operation amount) of the accelerator pedal, and an outside air temperature sensor 37 for detecting the outside air temperature are also connected to the ECU 50.

[0055] The ECU 50 includes a microprocessor that performs calculations, an EEPROM that stores programs and the like for causing the microprocessor to execute each process, a RAM that stores various data such as calculation results, a backup RAM whose stored content is retained by a battery, and an input / output I / F and the like. Further, the ECU 50 includes an injector driver that drives the injector 12, an output circuit that outputs an ignition signal, and a motor driver that drives the electronically controlled throttle valve 13 (electric motor 13a) and the like. Further, the ECU 50 also includes a driver that drives the solenoid valve 606 that constitutes the high-pressure fuel pump 60, a driver that drives the purge solenoid valve 73, a driver that drives the pump 772 (electric motor), a driver that drives the switching valve 771, and the like. Furthermore, the ECU 50 also includes a driver that drives each of the first on-off valve 95, the second on-off valve 96, the third on-off valve 97, and the fourth on-off valve 98 and the like.

[0056] In the ECU 50, the cylinder is discriminated from the output of the cam angle sensor 32, and the engine speed is obtained from the output of the crank angle sensor 33. Further, in the ECU 50, based on the detection signals input from the various sensors described above, various information such as the intake air amount, intake pipe negative pressure, accelerator pedal opening, air-fuel ratio of the air-fuel mixture, intake air temperature, atmospheric pressure, and the water temperature and oil temperature of the engine 10 is acquired. Then, based on these various pieces of information acquired, the ECU 50 comprehensively controls the engine 10 by controlling various devices such as the fuel injection amount, ignition timing, throttle valve 13, purge solenoid valve 73, switching valve 771, pump 772 (electric motor), and first on-off valve 95 to fourth on-off valve 98.

[0057] When the ECU 50 turns off the switching valve 771 to connect the atmosphere passage 778 and the orifice passage 777 and drives the pump 772 to detect the pressure (reference pressure) in the orifice passage 777, and then turns on the switching valve 771 to connect the evaporation passage 775 and the pump passage 776 and drives the pump 772 to detect the pressure in the evaporation passage (evaporation passage internal pressure), and then, based on the reference pressure and the evaporation passage internal pressure, diagnoses the presence or absence of an abnormality (such as a leak, etc.) in the evaporative fuel treatment system 70.

[0058] In particular, the pump sticking prevention device 90 including the ECU 50 has a function of preventing the sticking of the sliding part of the pump 772 that constitutes the diagnostic device 77 of the evaporative fuel treatment system (and preventing misdiagnosis). In the ECU 50, the function is realized by a program stored in an EEPROM or the like being executed by a microprocessor. The ECU 50 functions as the control unit described in the claims.

[0059] To realize the above-described functions, the ECU 50 controls the opening and closing of the first on-off valve 95, the second on-off valve 96, the third on-off valve 97, and the fourth on-off valve 98, respectively, and the driving (rotation) of the pump 772.

[0060] More specifically, when a predetermined cleaning control execution condition including engine stop is satisfied, the ECU 50 opens the first on-off valve 95 and the second on-off valve 96, respectively, and drives (rotates) the pump 772 to suck (draw in) the recovered liquid (cleaning liquid) into the pump 772 (that is, executes cleaning control).

[0061] Therefore, the recovered liquid (cleaning liquid) composed of low-boiling components of the fuel (such as gasoline) recovered and stored by the recovered liquid generation unit 91 is sucked into the pump 772 through the first pipe 92 by the negative pressure generated by the pump 772. Then, it is discharged through the rotating pump 772. As a result, the recovered liquid (cleaning liquid) flowing through the pump 772 washes away, for example, salts (compounds composed of anions and cations), water, wear powder, etc. that have accumulated in the sliding part of the pump 772 (i.e., can cause sticking of the pump 772). Note that it is preferable for the ECU 50 to increase the rotational speed of the pump 772 (for example, to about 2500 (rpm)) during the execution of the cleaning control.

[0062] Also, the ECU 50 opens the third on-off valve 97 during the execution of the cleaning control. Therefore, the recovered liquid (cleaning liquid) after washing away, for example, salts (compounds composed of anions and cations), water, wear powder, etc. that have accumulated in the sliding part of the pump 772 is returned to the fuel tank 80 through the second pipe 93.

[0063] Note that at that time (during the execution of the cleaning control), in order to enable the pump 772 to suck the recovered liquid (cleaning liquid) more efficiently, the ECU 50 closes the fourth on-off valve 98 (i.e., closes the intake port 772c of the pump 772).

[0064] After that, the ECU 50 ends (stops) the above-described cleaning control when the end (stop) condition of the cleaning control is met, for example, when a predetermined time has elapsed or when the recovered liquid (cleaning liquid) has run out.

[0065] As described in detail above, according to the present embodiment, first, the evaporated fuel generated in the fuel tank 80 is cooled, and low-boiling components of the fuel contained in the evaporated fuel are condensed and recovered to generate a recovered liquid (cleaning liquid). Then, when predetermined cleaning control execution conditions including engine stop are satisfied, the first on-off valve 95 and the second on-off valve 96 are each opened and the pump 772 is driven, and the recovered liquid is sucked into the pump 772 through the first pipe 92 (cleaning control is executed). Therefore, due to the negative pressure generated by the pump 772, the recovered liquid (cleaning liquid) composed of low-boiling components such as fuel (gasoline) is sucked into the pump 772 through the first pipe 92. And it is discharged through the rotating pump 772. Thus, the recovered liquid (cleaning liquid) can wash away, for example, salts (compounds composed of anions and cations), water, wear powder, etc. that have accumulated in the pump 772 (i.e., can cause sticking of the pump 772). As a result, it is possible to prevent sticking of the sliding portion of the pump 772 constituting the diagnostic device 77 of the evaporated fuel treatment system (and prevent misdiagnosis).

[0066] In addition, according to the present embodiment, since a part of the evaporated fuel can be removed in front of the canister 71, the load on the canister 71 can be reduced, and for example, the amount of activated carbon in the canister 71 can be reduced. Since the recovered liquid (cleaning liquid) mainly consists of low-boiling components such as gasoline, it has high volatility and will volatilize in a relatively short time even if it enters the sliding portion of the pump 772, so it will not cause the pump 772 to stick.

[0067] According to the present embodiment, a third on-off valve 97 for opening and closing the second pipe 93 is provided (interposed) in the second pipe 93 that communicates the recovered liquid discharge port / exhaust port 772e of the pump 772 and the fuel tank 80, and the third on-off valve 97 is opened during the execution of the cleaning control. Therefore, the recovered liquid after washing away, for example, salts (compounds composed of anions and cations), water, wear powder, etc. that have accumulated in the pump 772 can be returned to the fuel tank 80.

[0068] Further, according to the present embodiment, since the filter 94 is interposed in the second pipe 93 that communicates the recovered liquid discharge port 772e of the pump 772 with the fuel tank 80, foreign matters (such as abrasion powder) contained in the recovered liquid (cleaning liquid) returned to the fuel tank 80 through the second pipe 93 can be captured (collected).

[0069] According to the present embodiment, a fourth on-off valve 98 for opening and closing the intake port 772c of the pump 772 is provided, and the fourth on-off valve 98 is closed during the execution of the cleaning control. That is, the intake port 772c of the pump 772 is closed. Therefore, the pump 772 can suck the recovered liquid (cleaning liquid) more efficiently.

[0070] According to the present embodiment, grooves (discharge grooves) 772b that extend radially outward and obliquely upward of the rotor 772f are formed on the side surfaces of the plurality of vanes 772a that are formed in a substantially rectangular plate shape and are provided so as to be retractable in the radial direction of the rotor 772f. Therefore, the recovered liquid (cleaning liquid) can be discharged radially outward through the grooves 772b (along the grooves 772b), and the discharge effect of the recovered liquid can be further enhanced.

[0071] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications are possible. For example, the cleaning control execution conditions are not limited to the above embodiments, and can be arbitrarily set according to requirements and the like. For example, the cleaning control may be executed every time the engine stops, or the cleaning control may be executed when the engine stops at a predetermined cycle (time interval).

[0072] Also, in the above embodiment, a vane pump is used as the pump 772. However, the pump 772 is not limited to a vane pump, and for example, a trochoid pump or other types of pumps may be used.

[0073] In the above embodiment, as a method for cooling the evaporated fuel, for example, an air-cooling method using cooling fins or a water-cooling method by heat exchange with cooling water is used. However, instead of or in addition to these methods, the evaporated fuel may be cooled using, for example, a Peltier element or the like.

[0074] In the above embodiment, the present invention is applied to the diagnostic device (ELCM) 77 of the depressurized evaporated fuel treatment system. However, the present invention can also be applied to the diagnostic device (ELCM) of the pressurized evaporated fuel treatment system.

[0075] In the above embodiment, a linear solenoid whose opening degree changes according to the applied current value is used for the switching valve 771. However, instead of the linear solenoid, for example, a duty solenoid or the like whose opening degree changes according to the duty ratio of the voltage may be used.

[0076] Furthermore, in the above embodiment, the present invention is applied to a gasoline engine vehicle. However, the present invention can also be applied to engines such as HEVs (hybrid vehicles) and PHEVs (plug-in hybrid vehicles).

Explanation of Signs

[0077] 10 Engine 50 ECU 70 Evaporated fuel treatment system 71 Canister 72 Purge pipe 72a First purge pipe 72b Second purge pipe 73 Variable flow rate solenoid valve (purge solenoid valve) 77 Diagnostic device (ELCM) of the evaporated fuel treatment system 771 Switching valve 771a Valve (valve body) 772 Pump (negative pressure pump) 772a Vane 772b Groove (discharge groove) 772c Intake port 772d Recovery liquid suction port 772e Recovery liquid discharge port / exhaust port 772f Rotor 773 Pressure Sensor 774 Orifice 775 Evaporation Passage 776 Pump Passage 777 Orifice Passage 778 Atmosphere Passage 779 Filter 80 Fuel Tank 90 Pump Fixing Prevention Device 91 Recovery Liquid Generation Unit 92 First Pipe 93 Second Pipe 94 Filter 95 First On-Off Valve 96 Second On-Off Valve 97 Third On-Off Valve 98 Fourth On-Off Valve

Claims

1. A pump that generates negative pressure, A recovery liquid generation unit that is connected to a fuel tank for storing fuel, cools the evaporated fuel generated in the fuel tank, condenses and recovers the low-boiling components of the fuel contained in the evaporated fuel, and generates a recovery liquid, A first pipe that communicates the discharge port of the recovery liquid generation unit and the recovery liquid suction port of the pump, A first on-off valve that opens and closes the discharge port of the recovery liquid generation unit, A second on-off valve that opens and closes the recovery liquid suction port of the pump, A control unit that controls the opening and closing of each of the first on-off valve and the second on-off valve, and the driving of the pump, The control unit executes a cleaning control in which when a predetermined cleaning control execution condition including engine stop is satisfied, each of the first on-off valve and the second on-off valve is opened, the pump is driven, and the recovery liquid is sucked into the pump through the first pipe. A pump sticking prevention device characterized by that.

2. A second pipe that communicates the recovery liquid discharge port of the pump and the fuel tank, A third on-off valve that opens and closes the second pipe, The control unit opens the third on-off valve when executing the cleaning control. The pump sticking prevention device according to claim 1, characterized by that.

3. A fourth on-off valve that opens and closes the intake port of the pump is provided, The control unit closes the fourth on-off valve when executing the cleaning control The pump sticking prevention device according to claim 2, characterized by that.

4. The pump is a vane pump having a plurality of vanes formed in a substantially rectangular plate shape and provided so as to be retractable in the radial direction, The pump sticking prevention device according to claim 3, characterized in that a groove extending radially outward is formed on the side surface of the vane.

5. The pump sticking prevention device according to claim 4, further comprising a filter that is interposed in the second pipe and captures foreign substances contained in the recovery liquid returned to the fuel tank.

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