JP2002332921A - Evaporative fuel treating device, and failure diagnosis device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency of an evaporative fuel treating device using a purge pump. SOLUTION: Air for purge is supplied by a purge pump 108 to a canister 101, and desorbed fuel is purged to an intake pipe 201 in this evaporative fuel treating device. An ECU 112 intermittently actuates the purge pump 108, so that internal temperature of the canister lowered by latent heat of vaporization during actuation periods of the purge pump 108 is recovered to facilitate desorption in the actuation periods. Real actuation time is shortened, thereby the service life of a motor 7 as a power output section of the purge pump 108 can be extented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporative fuel treatment system for an internal combustion engine and a failure diagnosis system therefor.

[0002]

2. Description of the Related Art An internal combustion engine using highly volatile oil such as gasoline is provided with an evaporative fuel processing device in order to prevent evaporative fuel volatilized in a fuel tank from being released into the atmosphere. As the evaporative fuel processing apparatus, one having a canister is widely known. The canister is a container in which an adsorbent having a function of adsorbing fuel is sealed in a container. Evaporated fuel from a fuel tank introduced from an evaporative fuel introduction port is temporarily adsorbed by the adsorbent. When the internal combustion engine is operated and a negative pressure is generated in the intake pipe, the negative pressure supplies air to the canister from an atmospheric port, and fuel is released from the adsorbent and purged from the purge port to the intake pipe. The purged fuel is sucked into the cylinder together with the intake air to form a part of the air-fuel mixture.

[0003] In a direct injection type internal combustion engine that performs stratified charge combustion or an internal combustion engine mounted on a hybrid vehicle that uses an internal combustion engine and a motor as power, the opening of a throttle valve is relatively set to a fully open side. As a result, the negative pressure of the intake pipe is reduced, but the purging ability of the evaporated fuel is reduced. Therefore, a purge pump is provided on the atmosphere port side or on the purge port side to increase the pressure on the atmosphere port side of the canister and the negative pressure on the purge port side, thereby promoting the supply of air into the canister and reducing the intake pipe load. A device that compensates for insufficient pressure has been proposed (Japanese Patent Laid-Open No. 5-34).
No. 0315).

There has also been proposed a method in which the amount of purge is adjusted by switching the rotation of a purge pump (JP-A-11-30185).

[0005]

However, Japanese Patent Application Laid-Open No. 5-340315 and Japanese Patent Application Laid-Open No.
The technique disclosed in the above publication merely increases the purging capacity by simply operating the purge pump, and is not always practical in consideration of the loss of auxiliary equipment and the life of the purge pump, especially its power unit.

The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a practical fuel vapor treatment device having a purge pump.

[0007]

According to the first aspect of the present invention, an evaporative fuel introduction port communicating with the fuel tank, a purge port communicating with the intake pipe of the internal combustion engine, and an atmosphere port opened to the atmospheric pressure are provided. In the formed container, there is provided a canister in which an adsorbent for adsorbing fuel vapor from the fuel tank is sealed, and a purge pump supplies air from the atmosphere port into the canister by a purge pump to remove the fuel desorbed from the adsorbent. In the evaporative fuel processing apparatus configured to purge the air from the purge port to the intake pipe, a control unit for controlling the purge pump is provided, and the control unit is set so that the purge pump operates intermittently.

[0008] The intermittent operation causes the temperature in the canister, which has decreased during the actual operation period due to the latent heat of vaporization at the time of fuel desorption, to be reduced by the heat transfer from the installation atmosphere of the canister, etc. It recovers during the period, and the desorption of fuel becomes easy. Therefore, fuel purging can be performed efficiently. In addition, the actual operation time is shortened by the non-operation period, and the life of the purge pump can be extended. Thereby, practicality improves.

According to a second aspect of the present invention, in the configuration of the first aspect, a heater for heating the inside of the canister is provided.

[0010] The temperature drop in the canister during the operation period is more fully recovered during the non-operation period, and purging can be performed more efficiently. Since the load on the purge pump is reduced as much as the temperature drop in the canister is sufficiently recovered,
A low-power purge pump is sufficient, and the life of the purge pump can be further extended.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the control unit controls the purge valve together with a purge pump to control a purge valve for switching between communication and shutoff between a canister and an intake pipe. The purge pump and the purge valve are intermittently operated, and the timing at which the purge valve is opened is set to be delayed by a predetermined time from the timing at which the purge pump is turned on.

The period in which the air flow becomes unstable due to the delay in the activation of the purge pump is excluded from the actual purge period by delaying the timing of opening the purge valve with respect to the timing of turning on the purge pump. Therefore, the linearity of the purge flow rate with respect to the length of the open period of the purge valve is improved. As a result, the purge amount can be accurately controlled.

According to a fourth aspect of the present invention, in the configuration of the first or second aspect of the present invention, the control section controls the purge valve together with the purge pump to control a purge valve for switching between communication and shutoff between the canister and the intake pipe. The purge pump and the purge valve are intermittently operated, and the timing at which the purge valve is closed and the timing at which the purge pump is turned off are set to be substantially at the same time.

Since the purge valve closes almost simultaneously when the purge pump is turned off, the period after the purge pump is turned off, in which the discharge air flow rate gradually decreases and is not constant, is excluded from the actual purge period. Therefore, the linearity of the purge flow rate with respect to the length of the open period of the purge valve is improved. As a result, the purge amount can be accurately controlled.

According to a fifth aspect of the present invention, in the configuration of the third aspect of the present invention, the controller is set so that the timing at which the purge valve is closed and the timing at which the purge pump is turned off are substantially at the same time.

In addition to the function of excluding a period during which the air flow becomes unstable due to the delay in activation of the purge pump from the actual purge period, the purge valve closes almost simultaneously when the purge pump is turned off, so that the discharge air flow gradually decreases. The period after the irregular purge pump is turned off is also excluded from the actual purge period. Therefore, the linearity of the purge flow rate with respect to the length of the open period of the purge valve is further improved. Thereby, the purge amount can be controlled more accurately.

According to a sixth aspect of the present invention, in the configuration of the first to fifth aspects of the present invention, the control unit is provided with a purge pump such that the larger the command purge amount is, the longer the actual operation time during the intermittent operation is. Set to determine the number of on / off repetitions.

The life of the purge pump can be extended by limiting the use of the purge pump by defining the total of the actual operation time in accordance with the command purge amount. In the case where the heater is provided with the heater according to the second aspect, the cumulative operation time can be further shortened by the desorption accelerating action of the heater, and the substantial life of the purge pump can be extended. A simple brush motor or the like can be used as a power source.

According to a seventh aspect of the present invention, in the configuration of the first to fifth aspects of the present invention, the fuel vapor concentration is provided in the middle of the pipeline from the purge port to the intake pipe and detects the fuel vapor concentration. Equipped with a sensor, the control unit,
When the fuel vapor concentration reaches a preset purge completion concentration, the operation of the purge pump is stopped.

By sequentially monitoring the concentration of the fuel vapor, it is possible to avoid operating the purge pump in a state where the fuel vapor concentration decreases and the purge efficiency is not good. This allows
The life of the purge pump can be extended. Further, the purge period can be set appropriately regardless of the environmental factors such as the ambient temperature and the fuel properties.

According to the invention of claim 8, in the configuration of the inventions of claims 1 to 5, a purge flow rate adjusting means for adjusting a flow rate of the purge to the intake pipe, and a pipe flow path from the purge port to the intake pipe. An evaporative fuel concentration sensor for detecting the concentration of the evaporative fuel is provided on the way, and the control unit calculates the purge fuel amount based on the purge flow rate by the purge pump and the detection result of the evaporative fuel concentration sensor. Then, the purge flow rate is determined so that the purge fuel amount falls within a preset management range. The purge flow rate adjusting means may be constituted by means for adjusting the drive voltage of the purge pump, the duty of the purge valve, or the opening of a metering valve provided on the discharge side or the suction side of the purge pump.

At any time, a constant amount of purge fuel can flow into the intake pipe.

According to a ninth aspect of the present invention, in the configuration of the eighth aspect, a heater for heating the inside of the canister is provided, and the control unit is a control unit for controlling the purge pump and the heater. In the non-operating state, when the purge pump alone does not fall within the management range, the operation of the heater is started.

If the amount of purge fuel is small, the purge pump will be increased to its maximum capacity. If the lower limit of the management range is not reached, the operation of the heater is started. By operating the heater in a limited manner, power consumption can be suppressed.

According to a tenth aspect of the present invention, in the configuration of the eighth or ninth aspect, a fuel remaining amount sensor for detecting a remaining amount of fuel stored in the fuel tank is provided, and the control unit is provided with a fuel remaining amount sensor. When the amount falls below a preset lower limit, the operation of the heater is stopped.

If the lower limit is set to be slightly larger than, for example, the amount of fuel that is required to be refueled, the temperature of the canister, that is, the temperature of the adsorbent, decreases during refueling when evaporative fuel is likely to be generated, and the adsorbing performance is sufficiently improved. It can be in a state where it can be demonstrated. In some cases, refueling may be performed in a state where fuel is relatively left.However, in this case, since the refueling amount is small and the amount of evaporative fuel itself is small, the heater is in the operating state, that is, the adsorbent temperature is sufficiently reduced. Even if refueling is performed in a state where the fuel is not supplied, the adsorbent can adsorb the entire amount of the evaporated fuel.

In the eleventh aspect of the present invention, in the constitution of the eighth to tenth aspects, an evaporative fuel concentration sensor for detecting the concentration of the evaporative fuel is provided in the middle of the pipe from the purge port to the intake pipe. The controller is configured to stop the operation of the heater when the fuel vapor concentration falls below a preset lower limit concentration.

If the fuel vapor concentration is lower than the lower limit concentration,
It is determined that the amount of fuel adsorbed by the adsorbent in the canister is small, and the operation of the heater is stopped. Thereby, power consumption can be suppressed and auxiliary equipment loss can be reduced.

According to a twelfth aspect of the present invention, in the configuration of the eighth to eleventh aspects, a tank internal pressure sensor for detecting an internal pressure of the fuel tank is provided, and the control unit is provided with a lower limit in which the fuel tank internal pressure is set in advance. When the pressure falls below, the operation of the heater is set to be stopped.

If the internal pressure of the fuel tank is lower than the lower limit pressure, it is determined that the flow of the evaporated fuel from the fuel tank into the canister is small, and the operation of the heater is stopped. This allows
Power consumption can be suppressed, and auxiliary equipment loss can be reduced.

According to the thirteenth aspect of the present invention, there is provided a container in which an evaporative fuel introduction port communicating with the fuel tank, a purge port communicating with the intake pipe of the internal combustion engine, and an atmospheric port opened to the atmospheric pressure are formed. A canister in which an adsorbent for adsorbing fuel vapor from the fuel tank is sealed, and air purged from the air port into the canister by a purge pump, and the fuel desorbed from the adsorbent is supplied from the purge port to the intake pipe. In the evaporative fuel processing apparatus, the opening degree is freely adjusted to adjust the flow rate of the purge pump, and the adjusting valve is controlled to adjust the opening degree of the adjusting valve. And a control unit.

The purge amount can be adjusted according to the opening of the metering valve. It is necessary to provide a configuration that adjusts the magnitude of the generated power of the power unit itself of the purge pump by adjusting the discharge flow rate of the purge pump by the metering valve, for example, a circuit that adjusts the power supply amount to the motor that is the power unit. Absent. This simplifies the configuration and improves practicability.

According to the fourteenth aspect of the present invention, the container in which the evaporated fuel introduction port communicating with the fuel tank, the purge port communicating with the intake pipe of the internal combustion engine, and the atmosphere port opened to the atmospheric pressure are formed. A canister in which an adsorbent for adsorbing fuel vapor from the fuel tank is sealed, and air purged from the air port into the canister by a purge pump, and the fuel desorbed from the adsorbent is supplied from the purge port to the intake pipe. In the evaporative fuel processing apparatus that is configured to purge, a heater for heating the interior of the canister, and a control unit for controlling the purge pump and the heater, the control unit, prior to starting the operation of the purge pump, Set the heater to operate.

Prior to purging, the temperature inside the canister is raised in advance to facilitate the desorption of fuel from the adsorbent, so that purging can be performed efficiently. In addition, since the load on the purge pump is reduced, a low-output purge pump is sufficient, and the life of the purge pump can be extended. Thereby, practicality improves.

According to the fifteenth aspect of the present invention, the container in which the evaporated fuel introduction port communicating with the fuel tank, the purge port communicating with the intake pipe of the internal combustion engine, and the atmospheric port opened to the atmospheric pressure are formed. A canister in which an adsorbent for adsorbing fuel vapor from the fuel tank is sealed, and air purged from the air port into the canister by a purge pump, and the fuel desorbed from the adsorbent is supplied from the purge port to the intake pipe. And a control section for controlling the purge pump, and a refueling detection sensor for detecting whether or not refueling has been performed in the fuel tank. Is set, the operation of the purge pump is started.

Since a large amount of fuel vapor is generated by refueling, purging can be performed efficiently by performing purging when refueling is performed. Since the purge pump stops after a predetermined period of time, the life of the purge pump can be extended. Thereby, practicality improves.

Since the stop time of the purge pump is determined by the concentration of the evaporated fuel, the purge period can be appropriately set irrespective of environmental factors such as ambient temperature and fuel properties.

According to the present invention, the container in which the evaporated fuel introduction port communicating with the fuel tank, the purge port communicating with the intake pipe of the internal combustion engine, and the atmospheric port opened to the atmospheric pressure are formed. A canister in which an adsorbent for adsorbing fuel vapor from the fuel tank is sealed, and air purged from the air port into the canister by a purge pump, and the fuel desorbed from the adsorbent is supplied from the purge port to the intake pipe. And a control unit for controlling the purge pump, provided in the middle of a pipe line from the purge port to the intake pipe,
An evaporative fuel concentration sensor for detecting the concentration of the evaporative fuel is provided, and the control unit is set so that the operation of the purge pump is started when the concentration of the evaporative fuel exceeds a preset concentration.

By purging when a large amount of fuel vapor is generated, purging can be performed efficiently and the life of the purge pump can be extended. This improves the practicality.

According to the seventeenth aspect of the present invention, the container in which the evaporated fuel introduction port communicating with the fuel tank, the purge port communicating with the intake pipe of the internal combustion engine, and the atmosphere port opened to the atmospheric pressure are formed. A canister in which an adsorbent for adsorbing fuel vapor from the fuel tank is sealed, and air purged from the air port into the canister by a purge pump, and the fuel desorbed from the adsorbent is supplied from the purge port to the intake pipe. And a control unit for controlling the purge pump, provided in the middle of a pipe line from the purge port to the intake pipe,
An evaporative fuel concentration sensor for detecting the concentration of the evaporative fuel, the controller calculates a purge fuel amount based on the purge flow rate and the detection result of the evaporative fuel concentration sensor, and the purge fuel amount is set in advance. If the purge start fuel amount is exceeded,
Set the purge pump to operate.

By purging when a large amount of evaporative fuel is generated, purging can be performed efficiently and the life of the purge pump can be extended. This improves the practicality.

According to the eighteenth aspect of the present invention, the container in which the evaporated fuel introduction port communicating with the fuel tank, the purge port communicating with the intake pipe of the internal combustion engine, and the atmospheric port opened to the atmospheric pressure are formed. A canister in which an adsorbent for adsorbing fuel vapor from the fuel tank is sealed, and air purged from the air port into the canister by a purge pump, and the fuel desorbed from the adsorbent is supplied from the purge port to the intake pipe. In the evaporative fuel processing apparatus, the purge pump is driven by a motor connected to a shaft end of an impeller rotatably disposed in a pump housing, and the rotational energy of the impeller is Along with a circumferential flow system in which air is drawn from the suction port and transmitted to the air flowing through the pump housing to the discharge port,
The connection between the impeller and the rotating shaft of the motor is structured so that the impeller and the rotating shaft of the motor are slidable in the thrust direction, and the contact surface between the impeller and the rotating shaft of the motor is centered on the rotating shaft of the motor. The structure has a non-slip portion inclined with respect to the circumferential direction and a gap between the impeller and the motor rotating shaft in the thrust direction facing surface.

Since the impeller has play in the thrust direction with respect to the motor rotation shaft within the gap, even if the motor is displaced in the thrust direction, interference between the impeller and the housing is prevented. Thus, overload is not applied to the motor, purging can be performed efficiently, and the life of the purge pump can be extended. This improves the practicality.

According to a nineteenth aspect of the present invention, in the configuration of the eighteenth aspect, the bearings of the impeller are provided on both sides of the main body of the impeller.

Since the shaft of the impeller is supported at both ends, the axis of the impeller does not tilt and interference between the impeller and the housing is prevented. Thereby, it is possible to prevent the motor from being overloaded.

According to a twentieth aspect of the present invention, there is provided a failure diagnostic apparatus for detecting an abnormal operation of an evaporative fuel processing apparatus according to any one of the first to nineteenth aspects, wherein a purge valve for switching between communication and cutoff between a canister and an intake pipe. A pressure sensor that detects a pressure in a closed space including the canister and the fuel tank formed by being shut off from the intake pipe by a purge valve, and outputs a detection signal to the control unit; and a purge valve closed. And a determining unit for operating the purge pump in this state to pressurize the closed space and determine an operating state of the purge pump based on a rate of increase in pressure detected by a pressure sensor.

If the purge pump is normal, the pressure in the closed space rises at a predetermined rising speed due to its operation. However, if the air discharge capability is reduced due to the abnormality of the purge pump, the pressure rising speed becomes normal. Lower than that. Thus, the operating state of the purge pump can be determined based on the rate at which the pressure increases.

According to a twenty-first aspect of the present invention, in the configuration of the twentieth aspect, the determination section compares the pressure detected by the pressure sensor with a preset target pressure and sets a state in which the purge valve is closed. If the operation time of the purge pump exceeds the upper limit time in a state where the detected pressure does not reach the target pressure as compared with the upper limit time set in advance, the purge pump is determined to be abnormal. .

If the pressure rise rate in the closed space decreases, the time to reach the target pressure becomes longer, and if the operation time of the purge pump with the purge valve closed exceeds the upper limit time, it is determined that the purge pump is abnormal. Can be.

[0050]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, an evaporative fuel treatment apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 shows an evaporative fuel treatment apparatus of the present invention attached to an internal combustion engine. The canister 101 of the evaporative fuel processing apparatus 1 includes a container body 301 filled with an adsorbent 302 such as activated carbon, in which an evaporative fuel introduction port 301a, a purge port 301b, and an atmosphere port 301c are formed.
A heater 109 for heating the inside and a thermocouple 113 for detecting the temperature inside the canister 101 are provided. The heater 109 and the thermocouple 113 are buried in the filled adsorbent 302.

An evaporative fuel introduction passage 102 having an evaporative fuel introduction port 301a as a passage end is provided.
1 and the fuel tank 105 are connected. An internal pressure valve 106 is provided in the middle of the fuel vapor introduction passage 102. The internal pressure valve 106 is a relief valve. The internal pressure valve 106 is opened when the differential pressure across the fuel vapor introduction passage 102 sandwiching the internal pressure valve 106 becomes equal to or higher than a predetermined value due to an increase in fuel vapor in the fuel tank 105. The evaporative fuel in the fuel tank 105 is introduced into the canister 101.

The purge port 301b of the canister 101
Is provided, and the canister 101 and the intake pipe 201 are connected. A purge valve 107 is provided in the middle of the purge passage 103.
The purge valve 107 is an electromagnetic valve, and when it is switched to the “open” side by energization, the canister 101 communicates with the intake pipe 201. The purge passage 103 is also provided with an HC concentration sensor 114 that is an evaporative fuel concentration sensor that detects the concentration of HC in the passage.

An atmosphere passage 104 having an atmosphere port 301c of the canister 101 as a passage end is provided, and is opened to the atmosphere at an opposite passage end. A purge pump 108 described later in detail is provided in the middle of the atmosphere passage 104. The purge pump 108 includes a pump body 1081 and the motor 7 as a power source thereof, and supplies air from the atmosphere into the canister 101. As the motor 7, for example, an inexpensive DC brush motor can be used.

An ECU 112 is provided as a control section for controlling each section of the fuel vapor processing apparatus 1. The ECU 112 is mainly configured by a microcomputer or the like, for example. EC
U112 includes the thermocouple 113, the HC concentration sensor 11
4, a level gauge 1 provided in the fuel tank 105 for detecting the level of the liquid level FS of the fuel F, that is, the fuel amount.
15, detection signals are input from the ECU 15, and based on these detection signals, the purge valve 107, the purge pump 108,
The heater 109 is controlled. Note that the purge pump 108,
The control of the heater 109 is performed by outputting a drive signal to a power supply 110 for a motor and a power supply 111 for a heater. The energization of the motor 402 by applying a constant voltage to the motor power supply 110 is controlled on and off based on a drive signal from the ECU 112. The power supply to the heater 111 is controlled to be turned on and off based on a drive signal from the ECU 112 to energize the heater 109.

The ECU 112 controls the fuel vapor processing system 1
Not only that, other parts of the internal combustion engine, for example, the intake pipe 20
1 controls the throttle valve 202 provided therein, and controls the overall operation of the internal combustion engine.

FIG. 2 shows the flow of the fuel vapor purge control executed by the ECU 112. First, it is determined whether or not the ignition has been turned on (step S10).
1) If an affirmative determination is made, the process proceeds to step S102, and the procedure of the forced purge after step S102 is executed. If the ignition is not turned on, this flow ends.

In step S102, the level gauge 115
It is determined based on the detection signal from whether or not refueling has been performed. This determination is made based on whether or not the level of the liquid level FS of the fuel F in the fuel tank 105, which is known from the detection signal of the level gauge 115, has risen compared to when the flow was last started. In order to avoid erroneous determination due to an instantaneous level rise, data at the same level for a certain period of time or more is used for the determination. The previous level data of the liquid level FS is stored in a predetermined area of the RAM. ECU 112
Is an energy-saving operation such as a battery backup or a sleep mode. Even when the internal combustion engine is stopped, the data of the previous liquid level FS is retained. The data of the previous level is updated by the current liquid level each time this flow is started.

If an affirmative determination is made in step S102, the procedure of forced purging from step S104 is executed.

If no refueling has been performed, step S1
02 is negative, the process proceeds to step S103 and H
It is determined whether the HC concentration known from the C concentration sensor 114 is equal to or higher than the purge start concentration C1. The purge start concentration C1 is set to a concentration that is deemed to require purging. This may be obtained experimentally in advance. If an affirmative determination is made in step S103, the procedure of the forced purge (step S1)
04-). The case where a negative determination is made in step S103 will be described later.

In the procedure of the forced purge after step S104, first, the heater 109 is turned on (step S10).
4) The inside of the canister 101 is heated. This facilitates desorption of the fuel from the adsorbent 302. Next, based on the detection signal from the thermocouple 113, the canister 101
It is determined whether or not the temperature in the chamber is equal to or higher than a preset purge start temperature T1 (step S105).

The canister 10 is heated by the heater 109.
When the temperature in the internal combustion engine 1 rises and step S105 is affirmatively determined, the number of cycles defining the contents of the control signal of the motor 7 of the purge pump 108 is calculated (step S10)
6). The control signal of the motor 7 is output in the form of a pulse with the same period and the same pulse width, and the motor 7 is energized only during the pulse output period. The number of cycles is this number of pulses,
The energization of the motor 7 is intermittently performed for the number of cycles. The procedure for calculating the number of cycles will be described later. In the following step S106, a control signal corresponding to the calculated number of cycles is output to motor power supply 110. At this time, a control signal synchronized with this is output to the purge valve 107, and the purge valve 107 and the purge pump 108 perform an intermittent operation in synchronization.

FIG. 3 shows the fuel vapor processing apparatus 1 when the purge valve 107 and the purge pump 108 are intermittently operated.
In the open period (on period) of the purge valve 107, the rising timing of the motor drive signal is on, that is, while the voltage is being applied to the motor 7. The delay time is set slightly later than the rising timing of the drive signal. The fall timing is the same during the period when the motor drive signal is on and during the “open” period of the purge valve 107. Therefore, the intake pipe 20
The period during which the fuel is discharged to 1 is defined by the “open” period of the purge valve 107.

Here, the delay time is set as follows. As is known from FIG. 3, there is a delay in the actual rotation of the purge pump 108 before the motor drive signal rises to a predetermined number of revolutions due to the start delay of the motor 7. Since the rotation of the purge pump 108 regulates the flow rate of the air flowing through the canister 101,
The flow rate of the air containing the desorbed fuel at the purge port 301b of the canister 101 (hereinafter referred to as the purge flow rate) also has a delay in reaching the predetermined flow rate. The delay time is set to approximately this delay. This size is preferably determined experimentally in advance. Note that the time required for the desorbed fuel to move from the canister 101 to the purge valve 107 is a transport delay. Therefore, depending on the length of the purge passage 103, the transport delay may be added to the delay time.

By closing the purge valve 107 at the same time as the fall of the motor drive signal, the purge pump 1
08 operates by inertia and purge port 3 of the canister 101
Purging of the intake pipe 201 with fuel after the motor drive signal in which the fuel flow rate gradually decreases at 01b is prohibited.

Therefore, by setting the rise and fall of the purge valve 107 and the purge pump 108 in this manner, the flow rate of the fuel purged to the intake pipe 201 through the purge passage 103 is constant during the purge period. Thus, the purge amount per cycle is exactly proportional to the length of the “open” period of the purge valve 107. Therefore, the total amount of fuel purge by the execution of the step S107 is proportional to the time obtained by multiplying the length of the on-period of the purge valve 107 by the number of cycles (hereinafter, referred to as necessary on-time).

The procedure for calculating the number of cycles (step S106) is performed as follows. The ECU 112 stores the correspondence between the target purge amount and the required on-time in the ROM. The target purge amount is set based on the purge amount allowed from the operating state of the internal combustion engine. The number of cycles is calculated by dividing the required on-time for the target purge amount by the length of the on-period of the purge valve 107. This makes it possible to set the purge amount suitable for the operating state of the internal combustion engine. If the target purge amount can be constant according to the required specifications, the number of cycles is also a fixed value.

As a result, the accuracy of adjusting the amount of purge fuel that forms a part of the air-fuel mixture is improved, and the amount of fuel supplied to the cylinder can be controlled with high accuracy.

As shown in FIG. 3, during the purge period in which air flows through the canister 101 and fuel desorbs from the adsorbent 302, the temperature inside the canister 101 decreases due to latent heat of vaporization of the fuel. Is performed intermittently, the temperature in the canister 101 rises due to the heat transfer from the atmosphere in which the canister 101 is installed or the heating of the heater 109 during the non-purge period, so that the fuel can be easily detached from the adsorbent 302. To return to. Therefore, the fuel purging efficiency is improved. Further, by providing the purge pump 108 with a non-operation period sandwiched between the actual operation periods, the life of the motor 7 can be prolonged, and the heater 109 does not need to have an excessive capacity. And a small-sized one with a small number can be used. Further, the cumulative operation time of the motor 7 can be considerably reduced by the desorption promoting action of the heater 109. Accordingly, as described later, a simple brush motor or the like can be employed as a power source of the purge pump 108.

When the intermittent operation of the purge valve 107 and the purge pump 108 is performed for a predetermined number of cycles as described above, it is determined based on the detection signal from the HC concentration sensor 114 whether or not the HC concentration is equal to or lower than the purge completion concentration C0. A determination is made (step S108). The purge completion concentration C0 is set to a value at which the desorption of fuel from the adsorbent 302 is considered to be substantially completed.

While the HC concentration does not reach the purge completion concentration C0, that is, while the fuel to be purged still remains in the canister 101, a negative determination is made in step S108, and steps S106 to S108 are repeated.

When the HC concentration reaches the purge completion concentration C0 and the determination in step S108 is affirmative, the process proceeds to step S109, where the heater 109 is turned off.

As described above, the necessity of the forced purge is determined based on the presence or absence of refueling and the HC concentration, and the forced purge is executed for a predetermined period only when necessary, so that the fuel purge can be efficiently performed. it can.

Furthermore, when the HC concentration is sufficiently reduced, the forced purge is terminated, so that the forced purge is performed only for a necessary period regardless of the temperature of the atmosphere in which the canister 101 is installed and the properties of the fuel. Therefore, the purging efficiency is further improved.

In the following step S110, it is determined whether or not the time elapsed since the purge pump 108 was turned off has reached the standby time t0. In step S110, it is also determined about another elapsed time, which will be described later. The time from when the purge pump 108 is turned off is counted based on a timer that starts from the last time the purge valve 107 and the purge pump 108 are turned off (step S107). Note that H
Until the C concentration reaches the purge completion concentration C0 (step S
108) denotes a purge valve 107 and a purge pump 10.
8 is repeatedly turned on and off (step S107), so that the timer is reset each time.

When the elapsed time from the turning off of the purge pump 108 reaches the standby time t0, and the affirmative judgment is made in step S110, the process returns to step S101, and returns to step S101.
The subsequent steps are repeated. At this time, step S10
In the case of No. 2, when the judgment that refueling has already been made has been made last time, a negative judgment is made and the process proceeds to step S103. If the HC concentration exceeds the purge start concentration C1, as described above, the forced purge is executed (steps S104 to S104).

Thus, the fuel that has volatilized in the fuel tank 105 during the standby time t0 and that has been adsorbed by the adsorbent 302 of the canister 101 is purged. The standby time t0 is set to a time that is a measure of whether or not HC adsorbs to the adsorbent 302 to some extent due to the volatilization of the fuel that progresses during that time, and whether the HC concentration exceeds the purge start concentration C1. This may be obtained experimentally in advance.

The case where a negative determination is made in step S103 will be described. The negative determination in step S103 may include the case where the HC concentration has not reached the purge start concentration C1 or the case where the forced purge (from step S104) has been performed since the ignition was initially turned on. If a certain period of time has passed since the judgment, the fuel in the fuel tank 105 that progresses during that time will
Fuel may be adsorbed to some extent by the adsorbent 302 of the canister 101, and the HC concentration may increase. Therefore, step S10
If a negative determination is made in Step 3, the process proceeds to Step S110, and it is determined whether or not the elapsed time since the negative determination in Step S103 has exceeded the standby time t0.
The process returns to step S101 as in the case where the elapsed time since the purge pump 108 was turned off has reached the standby time t0.

Next, the structure of the purge pump 108 will be described with reference to FIG. 4, FIG. 5, FIG. 6, and FIG. The pump body 1081 is of a circumferential flow type. The housing 4 of the pump main body 1081 is formed by joining two substantially circular housing members 401 and 402 constituting the housing 4, and a circular space 4 a for accommodating the disk-shaped main body 51 of the impeller 5 is formed in an opposing portion thereof. You. In the housing 4, holes 4b, 4c, and 4d are formed in the joining direction of the housing members 401 and 402 at a position passing through the periphery of the space 4a and a position passing through the center of the space 4a.

A hole 4b and a hole 4c passing through the peripheral edge of the space 4a are formed at positions slightly shifted from each other in the circumferential direction, and one hole 4b is formed through one of the housing members 401 to penetrate therethrough. The other hole 4c is connected to one housing member 4
02 is formed through this. A pipe is fitted into one of the holes 4b and serves as an inlet 403 for introducing the atmosphere. Further, another pipe is fitted into the other hole 4c, and serves as an outlet 404 for discharging air. The outlet 404 communicates with the atmospheric port 301c of the canister 101.

A hole 4d passing through the center of the space 4a is formed to penetrate both housing members 401 and 402. The hole 4d has a shaft portion 52 of the impeller 5 passing through the impeller body 51.
And bearings 601 and 602 as bearings are provided coaxially with the outer periphery of the impeller shaft portion 52. The bearings 601 and 602 are provided in the impeller body 51.
Are provided at two positions, respectively, to suppress the displacement of the impeller 5 in the thrust direction and prevent the interference between the impeller 5 and the housing 4. Bearing 601 and 602
Are lid members 406, 407, 4 for substantially closing the holes 4d.
08.

A motor 7 is provided at the shaft end of the impeller 5 and is fixed to a mounting stay 405 provided integrally with the housing member 401. Shaft 5 of impeller 5
2, a vertical hole 5a having a bottom is formed from the end face on the motor 7 side along the axis, and the rotating shaft 71 of the motor 7 is fitted into the vertical hole 5a to connect the impeller 5 and the motor rotating shaft 71.

As shown in FIG. 6, a large number of blades 51 are arranged at equal intervals in the circumferential direction on both end surfaces of the impeller main body 51 (only the end surface on the housing member 402 side is shown in FIG. 6). When rotated, a swirling flow is generated on the outer periphery of the impeller shaft portion 52 along both end surfaces of the impeller main body 51, and air from the inlet 403 is discharged from the outlet 40.
4 is discharged.

In FIG. 7 showing the connection structure between the impeller 5 and the motor shaft 71, the vertical hole 5a of the shaft portion 52 of the impeller 5 and the shaft end of the rotating shaft 71 of the motor 7 to be fitted therein (hereinafter referred to as the motor shaft shaft end). The cross-sectional shape of the portion 711 is substantially circular, and has a D-shape in which a part of the circle is cut linearly.
By setting b and 71a, slippage of the impeller 5 with respect to the rotation of the motor rotation shaft 71 can be prohibited. Thereby, the rotational power of the motor 7 is transmitted to the impeller 5 without providing the fastening means.

On the other hand, the impeller shaft 52 and the motor shaft shaft end 711 are slidable in the thrust direction. A relatively large gap G is formed between the bottom surface 5c of the vertical hole 5a of the impeller 5 and the end surface 71b of the motor shaft 71, which is an opposing surface, and the impeller 5 moves in the thrust direction with respect to the motor shaft 71. Be free. Thus, even if the motor 7 is displaced in the thrust direction, the impeller 5 and the housing 4 do not interfere with each other due to the play in the thrust direction due to the gap G, so that the motor 7 is overloaded or stops rotating. Can be prevented.

As a result, the clearance between the impeller 5 and the housing 4 can be reduced, the loss of the purge pump 108 can be reduced, and efficient purging can be realized.

The cross-sectional shapes of the vertical hole of the impeller shaft and the end of the motor shaft are not limited to those shown in the drawings, and the contact surface between the impeller shaft and the end of the motor shaft is provided with the rotation of the impeller and the motor. It is sufficient that a portion inclined with respect to the circumferential direction with respect to the center is formed, and this portion serves as a slip stopper for inhibiting the impeller from slipping with respect to the rotation of the motor rotation shaft. For example, the cross-sectional shape may be an ellipse or a polygon. Further, the connection structure does not need to be a structure in which one of the impeller shaft portion and the motor shaft shaft end portion fits into a hole formed in the other, and is arbitrary.

(Second Embodiment) FIG. 8 shows an evaporated fuel processing apparatus according to a second embodiment of the present invention. The basic configuration is the same as that of the first embodiment, and differences from the first embodiment will be mainly described.

The fuel vapor processing apparatus 1A according to the first embodiment
4, a pump valve 116, which is a metering valve, is provided immediately downstream of the purge pump 108. Pump valve 1
Reference numeral 16 denotes a solenoid valve configured to be freely openable.
The opening is adjusted by the control signal from 2A.

FIG. 9 shows the relationship between the discharge pressure and the discharge flow rate of the purge pump 108 when the opening degree of the pump valve 116 is changed. As the opening degree is reduced, the discharge pressure increases and the discharge flow rate decreases. Become. In the present embodiment, the ECU 11
2A is to adjust the opening with respect to the target purge amount,
The discharge pressure and the discharge flow rate are adjusted to the target purge amount.

The amount of purge can be adjusted without making the voltage applied to the motor 7 variable, so that the motor power supply can be of a simple constant voltage output type. This allows
Practicality is improved.

The other controls executed by the ECU 112A are the same as those in the first embodiment.

Although the pump valve is provided on the discharge side of the purge pump, it may be provided on the suction side.

(Third Embodiment) FIG. 10 shows a fuel vapor processing apparatus according to a third embodiment of the present invention. The basic configuration is the same as that of the first embodiment, and differences from the first embodiment will be mainly described.

The ECU 112B of the fuel vapor processing system 1B
Executes a control program different from that of the first embodiment, and FIG. 11 shows a flow of evaporative fuel purge control executed by the ECU 112B. When the ignition is turned on (step S201), it is determined whether or not refueling has been performed (step S202). If the refueling has not been performed, the process proceeds to step S203, and the purge flow rate uniquely determined by the purge valve opening degree is determined. Then, in step S204, the HC concentration known from the HC concentration sensor 114 is inputted. Then, step S2
At step 05, a purge fuel amount is calculated based on the purge flow rate and the HC concentration. At step S206, it is determined whether the purge fuel amount is equal to or more than a predetermined value M2. Here, the predetermined value M2 is set to an amount of fuel that is determined to be required to be purged. This may be obtained experimentally in advance. If the determination in step S206 is affirmative, the procedure of the forced purge (from step S207) is executed. Step S2
The case where 06 is negatively determined will be described later.

In the procedure of the forced purge after step S207, first, the heater 109 is turned on (step S20).
7), the inside of the canister 101 is heated. This facilitates desorption of the fuel from the adsorbent 302. Next, based on the detection signal from the thermocouple 113, the canister 101
It is determined whether or not the temperature in the chamber is equal to or higher than a preset purge start temperature T1 (step S208).

The canister 10 is heated by the heater 109.
If the temperature in the power supply 1 rises and the determination in step S208 is affirmative, the process proceeds to step S209, in which the control signal for the motor 7 of the purge pump 108 is output to the motor power supply 110 in the form of pulses with an equal period and an equal pulse width. The motor 7 is energized only during the pulse output period. At this time, a control signal is output to the purge valve 107 in synchronization with the control signal of the motor 7, and the purge valve 107 operates in synchronization with the purge pump 108 as in the first embodiment. During a period in which the motor drive signal is on, that is, a period in which voltage is applied to the motor 7, the purge valve 107 is
During the open period (ON period), the rising timing is slightly later than the rising timing of the motor drive signal, and the delay time is set as in the first embodiment. The flow rate of the fuel purged into the pipe 201 is constant, and the amount of purge per cycle is exactly proportional to the length of the “open” period of the purge valve 107.

As a result, the accuracy of adjusting the amount of purge fuel that forms a part of the air-fuel mixture is improved, and the amount of fuel supplied to the cylinder can be controlled with high accuracy.

As in the first embodiment, the temperature inside the canister 101 rises due to the heat transfer from the atmosphere in which the canister 101 is installed and the heating of the heater 109 during the non-purge period during the intermittent operation of the purge valve 107 and the purge pump 108. Thus, the fuel purging efficiency is improved. Further, by providing the purge pump 108 with a non-operation period sandwiched between the actual operation periods, the life of the motor 7 can be extended, and
Excessive capacity is not required for the heater 109, and a small heater with low power consumption can be used.

When the intermittent operation of the purge valve 107 and the purge pump 108 is started as described above, HC
Based on the detection signal from the concentration sensor 114, it is determined whether or not the HC concentration is equal to or lower than the purge completion concentration C0 (step S210). The purge completion concentration C0 is set to a value at which the desorption of fuel from the adsorbent 302 is considered to be substantially completed.

While the HC concentration does not reach the purge completion concentration C0, that is, while the fuel to be purged still remains in the canister 101, step S210 is negatively determined, and steps S209 to S210 are repeated. As described above, since the purge amount obtained by executing the step S209 is constant, the total fuel purge amount is determined by the purge valve 1
It is proportional to the time obtained by multiplying the length of the ON period of 07 by the number of cycles.

When the HC concentration reaches the purge completion concentration C0 and the determination in step S210 is affirmative, the process proceeds to step S211 to turn off the purge pump 108 and turn off the heater 109. At this time, it goes without saying that the purge valve 107 is turned off.

As described above, the necessity of the forced purge is determined based on the presence or absence of refueling and the HC concentration, and the forced purge is executed for a predetermined period only when necessary, so that the fuel purge can be efficiently performed. it can.

Furthermore, when the HC concentration is sufficiently reduced, the forced purge is terminated, so that the forced purge is performed only for a required period regardless of the temperature of the atmosphere in which the canister 101 is installed and the properties of the fuel. Therefore, the purging efficiency is further improved.

In the following step S212, it is determined whether or not the elapsed time from when the purge pump 108 was turned off has reached the standby time t0. The elapsed time from when the purge pump 108 is turned off is counted based on a timer that starts when the purge pump 108 is turned off.

When the elapsed time from when the purge pump 108 is turned off reaches the standby time t0, and the determination in step S212 is affirmative, the process returns to step S201 and returns to step S201.
The subsequent steps are repeated. At this time, step S20
In the case of No. 2, when the judgment that refueling has already been made has been made last time, a negative judgment is made and the process proceeds to step S203. If the purge fuel amount exceeds the purge start fuel M2 as described above, the forced purge is executed (step S207).
~).

As a result, the fuel that has volatilized in the fuel tank 105 during the standby time t0 and has been adsorbed by the adsorbent 302 of the canister 101 is purged. The stand-by time t0 is a time when HC is adsorbed to the adsorbent 302 to some extent due to the volatilization of the fuel progressing during that time, and it becomes a standard whether or not the HC amount known from the HC concentration or the like exceeds the purge start fuel amount M2. Is set. This may be obtained experimentally in advance.

The case where a negative determination is made in step S206 will be described. The negative determination in step S206 may be that the HC amount has not reached the purge start fuel amount M2 from the beginning of turning on the ignition or that the forced purge (step S207-) has been performed. If a certain amount of time has passed since the time of the determination, the fuel in the fuel tank 105 that progresses during that time will evaporate,
Fuel may be adsorbed to some extent by the adsorbent 302 of the canister 101, and the HC concentration may increase. Therefore, step S20
If the determination in step S206 is negative, the process proceeds to step S212, and it is determined whether the elapsed time since the determination in step S206 is negative exceeds the standby time t0.
The process returns to step S201 as in the case where the elapsed time since the purge pump 108 was turned off has reached the standby time t0.

(Fourth Embodiment) FIG. 12 shows an evaporated fuel processing apparatus according to a fourth embodiment of the present invention. The basic configuration is the same as that of the second embodiment, and differences from the second embodiment will be mainly described.

The fuel vapor processing apparatus 1C according to the present embodiment comprises a fuel tank 1
05 is provided with a pressure sensor (hereinafter referred to as a tank internal pressure sensor) 117 for detecting the internal pressure, and a detection signal thereof is input to the ECU 112C. The ECU 112C is
FIG. 13 shows a flow of a fuel vapor purge control executed by the ECU 112C, which executes a control program different from that of the embodiment. When the ignition is turned on (step S301), the level gauge 115
It is determined whether or not the remaining amount of fuel in the fuel tank 105 is equal to or greater than a predetermined amount V0 based on the detection signal (step S).
302). If the remaining fuel amount is smaller than the predetermined amount V0, the control routine ends. Step S302 is for preventing fuel from adsorbing to the adsorbent 302 while the canister 101 is heated at the time of refueling.
When the temperature is high, it is advantageous for desorption, but disadvantageous for adsorption. If it is determined that the remaining amount of fuel in the fuel tank 105 is low, the heating control of the adsorbent 302 by the heater 109 is stopped. This will be described later.

In step S302, the remaining amount of fuel reaches the predetermined amount V0.
If so, the process proceeds to step S303. Step S30
In step 3, the purge flow rate uniquely determined by the opening of the purge valve 107 is input, and the HC concentration obtained by the HC concentration sensor 114 is input in step S304. Then, in step S305, a purge fuel amount is calculated from the purge flow rate and the HC concentration, and in step S306,
It is determined whether this purge fuel amount is within a predetermined management range (M0 ≦ purge fuel amount ≦ M1). Here, the management range is an amount in a range that does not deteriorate the combustion failure and the exhaust emission when the purge gas is introduced into the intake pipe 201.

In step S306, if the purge fuel amount is not within the management range (M0 ≦ purge fuel amount ≦ M1), the flow proceeds to step S307. In step S307, it is determined whether the purge fuel amount outside the management range is larger than the upper limit M1 of the management range. If it is larger than the upper limit value M1, the process proceeds to step S308, in which the purge flow rate is reduced to reduce the purge fuel amount, and then the process returns to step S301.

If it is determined in step S307 that the value is equal to or less than the upper limit value M1, it is determined that the value is less than the lower limit value M0.
Then, it is determined whether or not the purge flow rate is the maximum, that is, whether or not the opening of the metering valve 116 is the upper limit value of the adjustable range. If the purge flow rate is not the maximum, the process proceeds to step S310, and the purge flow rate is increased to increase the purge fuel amount. The steps S308 to S310 are performed in EC
This is a procedure of U112C as a purge flow rate adjusting unit.

If the purge flow rate is the maximum, it is determined that the purge fuel amount cannot be secured any more in the current state, and the flow advances to step S311 to turn on the heater 109.

The amount of purge fuel introduced into the engine body via the intake pipe 201 is determined not only by the HC concentration but also by the intake pipe 2
It also changes depending on the purge flow rate flowing into 01. Therefore, in steps S303 to S305, the purge fuel amount is calculated based on these values, and the operations of the purge pump 108 and the heater 109 are controlled so that the purge fuel amount falls within the management range (steps S306 to S311). At this time, first, the purge flow rate is adjusted, and when the predetermined purge amount cannot be obtained, heating by the heater 109 is started. As a result, the purge fuel amount is controlled within the management range,
Variations in the air-fuel ratio can be prevented to prevent poor combustion and deterioration in exhaust emissions.

Next, at step S312, the temperature sensor 1
13 is read, and it is determined whether the temperature of the adsorbent 302 in the canister 101 is equal to or higher than a predetermined temperature T0. In this case, the predetermined temperature T0 is a temperature at which the evaporated fuel in the canister 101 can be completely desorbed, and is usually 100 °
C is desirable. If the temperature of the adsorbent has not reached the predetermined temperature T0 in step S312, step S3
01, and if it is equal to or higher than the predetermined temperature T0, step S31
Proceed to 3. In step S313, the detection result of the tank internal pressure sensor 117 for monitoring the tank internal pressure is read, and it is determined whether or not the tank internal pressure is lower than a predetermined value P0, here, the opening pressure of the internal pressure valve 106. When the tank internal pressure is equal to or higher than the predetermined value P0, the internal pressure valve 106 is opened, and it is determined that the evaporated fuel flows into the canister 101.
It returns to step S301.

On the other hand, if the tank internal pressure is lower than the predetermined value P0, it is determined that there is no inflow of fuel vapor into the canister 101, and the flow advances to step S314 to execute the HC concentration sensor 114.
Then, it is determined whether or not the HC concentration monitored in step is below a predetermined concentration C0. If the HC concentration is equal to or higher than the predetermined concentration C0,
It is determined that fuel still remains in the canister 101, and the process returns to step S301, where the HC concentration is reduced to the predetermined concentration C0.
If not, it is determined that no fuel remains in the canister 101, and the process proceeds to step S315, where the heater 109
Is turned off and the control routine ends.

Steps S313 and S314 are intended to reduce power consumption. When the internal pressure of the fuel tank 105 is lower than the valve opening pressure and the HC concentration is less than the predetermined concentration C0, it is determined that heating by the heater 109 is not necessary, and the heater 109 is turned off to suppress power consumption.

On the other hand, when the engine is stopped, the heater 109 is not turned on, and there is no negative pressure in the intake pipe 201. Therefore, as the outside air temperature rises, the generated fuel vapor is only adsorbed to the canister 101. . That is, when the fuel evaporates in the fuel tank 105 and the internal pressure of the fuel tank 105 rises to a predetermined value or more, the internal pressure valve 106 opens and is discharged into the canister 101 through the evaporated fuel introduction passage 102 and the tank port 301a. At this time, when the engine is stopped, the fuel in the canister 101 has been substantially completely desorbed, so that the canister 101 is in a state capable of sufficiently adsorbing fuel vapor from the fuel tank 105,
The inflowing fuel vapor can be efficiently adsorbed. Further, since no evaporated fuel remains in the canister 101, it is possible to prevent the remaining evaporated fuel from diffusing inside the canister 101 and discharging from the atmosphere port to the atmosphere when the engine is stopped, as in the related art. it can.

At the time of refueling, the fuel vapor remaining in the fuel tank 105 opens the fueling valve in such a manner as to be pushed out by the fueling fuel, and flows into the canister 101 from the fueling line via the fuel vapor introducing passage 102. At this time, if the temperature of the adsorbent 302 is high, the adsorption performance decreases,
The heating by the heater 109 is stopped. That is, in the control routine of FIG. 13, when the remaining fuel amount becomes smaller than the predetermined amount V0, it is determined that refueling is necessary (step S302), and the heater 109 is turned off (step S302).
315). Normally, the predetermined amount V0 in step S302 is set to an amount slightly larger than the remaining fuel amount required for refueling, for example, １ ／ of the nominal capacity. As a result, the heater 109 is turned off when the remaining fuel amount drops to 1/4, so that the temperature in the canister 101 returns to substantially normal temperature during refueling, and the temperature of the canister 101, that is, the temperature of the adsorbent 302 is high. Adsorption can be prevented.

When refueling is performed in a state where the remaining fuel amount is larger than the predetermined amount V0 or immediately after the remaining fuel amount reaches the predetermined amount V0, the engine is stopped or when the remaining fuel amount reaches the predetermined amount V0. The heater 109 is turned off (steps S301 and S302), and the heater 109 is energized until immediately before refueling. In these cases, since the time until refueling is short, the temperature of the adsorbent 302 may not be sufficiently lowered. However, in this case, the amount of refueling is relatively small, and the amount of fuel that evaporates is also proportional to the amount of refueling. Therefore, the amount of evaporated fuel flowing into the canister 101 is not so large, and the adsorbent 302 of the canister 101 removes fuel. Since the separation is substantially completed, the entire amount of the evaporated fuel can be adsorbed.
Based on these, the remaining fuel amount V0 for turning off the heater 109 is set to an optimum value obtained from the capacity of the adsorbent 302 of the canister 101, the size of the fuel tank 105, and the amount of fuel vapor flowing into the canister 101. Is made to be able to adsorb the entire amount of the inflow evaporative fuel.

In this embodiment, the ECU 112C adjusts the purge flow rate by adjusting the opening of the pump valve 116. However, the ECU 112C adjusts the duty of the purge valve 107 and the drive voltage of the motor 7 to adjust the purge flow. The flow rate may be adjusted.

(Fifth Embodiment) FIG. 14 shows a failure diagnosis apparatus for an evaporative fuel treatment apparatus according to a fifth embodiment of the present invention. The basic configuration of the evaporative fuel processing apparatus is the same as that of the first embodiment, and differences from the first embodiment will be mainly described.

ECU 112D of the present evaporated fuel processing apparatus 1D
The purge pump 1 for detecting a failure of the motor 7 and the like based on the detection signal from the tank internal pressure sensor 117, together with the control of the forced purge similar to the ECU of any of the above embodiments.
A malfunction diagnosis device 1a is configured to detect an operation abnormality of the engine 08, and together with the purge valve 107 and the tank internal pressure sensor 117.

FIG. 15 shows a flow for detecting this operation abnormality. In a state where the purge pump 108 is turned on, the purge valve 107 is first closed (step S401), and the fuel is supplied from the fuel tank 105 to the purge valve 107 via the canister 101. Form an enclosed space. Step S401
Is a procedure as a control unit.

When the purge valve 107 is closed, the timer is started again. This and the following step S4
02 and S403 are procedures as a determination unit. With the timer started, the tank internal pressure known from the tank internal pressure sensor 117 is compared with a preset reference pressure to determine whether or not it is higher than the reference pressure (step S40).
2).

If step S402 is negative, the elapsed time after formation of the closed space, which is known from the timer, is compared with a preset reference time to determine whether the reference time has elapsed (step S403).

If step S403 is denied, the process returns to step S402 until the tank internal pressure exceeds the reference pressure before the elapsed time reaches the reference time, or until the elapsed time exceeds the reference time without the tank internal pressure exceeding the reference pressure. Step S
Steps 402 and S403 are repeated.

Here, the reference pressure and the reference time are set as follows. That is, if the purge pump 108 is normal and operates at a predetermined discharge pressure and discharge flow rate,
As shown in FIG. 16, the pressure in the closed space, that is, the tank internal pressure increases at a predetermined rising speed. After a lapse of a predetermined time, the pressure reaches a predetermined pressure. On the other hand, if the operation of the purge pump 108 is abnormal, the rate of increase in the tank internal pressure is slow or takes a constant value without increasing. Therefore, when the purge pump 108 can be considered to be normal, the upper limit value of the time required to reach the predetermined pressure is determined in advance as the reference time. The reference pressure is the predetermined pressure, and is set to a pressure value at which it can be determined whether or not a discharge pressure required for purging can be output. The time allowed as a time until a result is obtained regarding the presence or absence of an abnormality in the purge pump 108,
The pressure may be set in consideration of a pressure value that can be reached according to the normal capacity of the purge pump 108.

If the tank internal pressure exceeds the reference pressure before the elapsed time reaches the reference time, it is determined that the tank pressure is normal, and the flow ends. If the elapsed time exceeds the reference time without the tank internal pressure exceeding the reference pressure, the purge pump 108
Is determined to be abnormal, and a pump flow rate abnormality lamp indicating that the pump flow rate is abnormal is turned on (step S404).

The operation of the purge pump 108 in this case can be performed not by intermittent operation but by continuous operation.

Although the abnormality is determined when the elapsed time exceeds the reference time while the tank internal pressure does not exceed the reference pressure, the determination may be made based on the rising speed of the tank internal pressure at a predetermined time. .

In each of the above embodiments, the purge pump is provided in the atmosphere passage. However, the purge pump may be provided in the purge passage closer to the canister than the purge valve.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first evaporated fuel processing apparatus of the present invention.

FIG. 2 is a flowchart illustrating control executed by an ECU of the evaporated fuel processing apparatus.

FIG. 3 is a timing chart showing the operation of each unit when the evaporative fuel treatment apparatus performs a forced purge.

FIG. 4 is a cross-sectional view of a purge pump of the fuel vapor processing apparatus.

FIG. 5A is a view taken in the direction of arrow A in FIG. 4, and FIG.
FIG. 5 is a view on arrow B in FIG. 4.

FIG. 6 is a view of the impeller of the purge pump as viewed in the direction of arrow B in FIG. 4;

FIG. 7 is a sectional view of the impeller and a motor shaft connected thereto taken along line VII-VII in FIG. 4;

FIG. 8 is a configuration diagram of a second evaporated fuel processing apparatus of the present invention.

FIG. 9 is a graph showing the operation of the fuel vapor processing apparatus.

FIG. 10 is a configuration diagram of a third evaporated fuel processing apparatus of the present invention.

FIG. 11 is a flowchart showing control executed by an ECU of the evaporated fuel processing device.

FIG. 12 is a configuration diagram of a fourth evaporated fuel processing device of the present invention.

FIG. 13 is a flowchart showing control executed by an ECU of the evaporated fuel processing device.

FIG. 14 is a configuration diagram of an evaporative fuel processing apparatus provided with a failure diagnosis device for the evaporative fuel processing apparatus of the present invention.

FIG. 15 is a flowchart showing control executed by an ECU of the failure diagnosis device.

FIG. 16 is a graph showing an operation of the failure diagnosis device.

[Explanation of symbols]

 1, 1A, 1B, 1C, 1D Evaporated fuel processing device 1a Failure diagnosis device 101 Canister 102 Evaporated fuel introduction passage 103 Purge passage 104 Atmospheric passage 105 Fuel tank 106 Internal pressure valve 107 Purge valve 108 Purge pump 1081 Pump body 109 Heater 110 Motor power supply 111 Heater power supply 112, 112A, 112B ECU (control unit) 112C ECU (control unit, purge flow rate adjusting means) 112D ECU (control unit, determination unit) 113 Thermocouple (temperature sensor) 114 HC concentration sensor (evaporated fuel sensor) 115 Level gauge (fuel supply detection sensor) 116 Pump valve (metering valve) 117 Tank internal pressure sensor 201 Intake pipe 301 Container 301a Evaporated fuel introduction port 301b Purge port 301c Atmospheric port 302 Adsorbent 4 Ujingu 5 impeller 51 body 52 the shaft portion 5a longitudinal hole 5b slip portion 5c bottom (opposing surface) 6 bearing (bearing) 7 motor 71 shaft 711 axial end portion 71a slip portions 71b end surface (opposing surface) G gap

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F04D 29/04 F04D 29/04 F N (72) Inventor Hideaki Itakura 14 Iwatani, Shimowasukamachi, Nishio City, Aichi Prefecture Stock Inside the Japan Auto Parts Research Institute (72) Inventor Masaki Takeyama 14th Iwatani Shimoba Kakucho, Nishio City, Aichi Pref. Inside the Japan Automobile Parts Research Institute (72) Inventor Yoshihiko Bodo 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Mamoru Yoshioka 1 Toyota Town Toyota City, Aichi Prefecture Toyota Motor Corporation F term (reference) 3G044 BA23 BA32 CA17 DA02 DA06 DA07 EA03 EA10 EA18 EA23 EA30 EA32 EA35 EA55 EA57 FA04 FA08 FA1 0 FA12 FA23 FA24 GA02 GA03 GA04 GA05 GA09 GA11 GA16 GA22 GA23 GA24 GA27 GA29 3H022 AA01 BA03 BA06 CA01 CA07 CA12 CA20

Claims (21)

[Claims] 1. A container having an evaporative fuel introduction port communicating with a fuel tank, a purge port communicating with an intake pipe of an internal combustion engine, and an atmosphere port open to the atmospheric pressure.
A canister filled with an adsorbent for adsorbing fuel vapor from the fuel tank is provided.Air is supplied from the air port into the canister by a purge pump, and fuel desorbed from the adsorbent is supplied from the purge port to the intake pipe. An evaporative fuel processing apparatus for purging, comprising: a control unit for controlling the purge pump, wherein the control unit is set so that the purge pump operates intermittently. 2. The evaporative fuel processing apparatus according to claim 1, further comprising a heater for heating the inside of the canister. 3. The evaporative fuel processing device according to claim 1, wherein the control unit controls a purge valve that switches between communication and shutoff between a canister and an intake pipe together with a purge pump. An evaporative fuel processing apparatus wherein the purge pump and the purge valve are intermittently operated, and a timing at which the purge valve is opened is delayed by a predetermined time from a timing at which the purge pump is turned on. 4. The evaporative fuel processing apparatus according to claim 1, wherein the control unit controls a purge valve that switches between communication and shutoff between a canister and an intake pipe together with a purge pump. In addition, the evaporative fuel processing apparatus is set so that the purge pump and the purge valve operate intermittently, and the timing at which the purge valve closes and the timing at which the purge pump turns off are substantially at the same time. 5. The evaporative fuel processing apparatus according to claim 3, wherein the control unit is set such that a timing at which the purge valve closes and a timing at which the purge pump turns off are substantially at the same time. 6. The evaporative fuel processing apparatus according to claim 1, wherein the control unit is configured to turn on / off a purge pump so that the actual operation time during the intermittent operation increases as the command purge amount increases. An evaporative fuel treatment device set to determine the number of repetitions. 7. An evaporative fuel concentration sensor according to claim 1, further comprising a vapor fuel concentration sensor provided in the middle of a pipe from the purge port to the intake pipe for detecting the concentration of the evaporative fuel. An evaporative fuel processing apparatus, wherein the controller is configured to stop the operation of the purge pump when the evaporative fuel concentration reaches a preset purge completion concentration. 8. The evaporative fuel treatment apparatus according to claim 1, wherein a purge flow rate adjusting means for adjusting a flow rate of a purge to the intake pipe, and a purge flow rate adjusting means for adjusting a flow rate of the purge to the intake pipe. An evaporative fuel concentration sensor for detecting the concentration of the evaporative fuel. The controller calculates a purge fuel amount based on a purge flow rate and a detection result of the evaporative fuel concentration sensor, and calculates the purge fuel amount. Wherein the purge flow rate is set so that the purge flow rate is within a preset management range. 9. The evaporative fuel treatment apparatus according to claim 8, further comprising a heater for heating the inside of the canister, wherein the control unit is a control unit for controlling a purge pump and a heater, and the heater is not operated. An evaporative fuel processing device set to start operation of the heater when the operation does not fall within the management range due to operation of only the purge pump. 10. The evaporative fuel processing device according to claim 8, further comprising a fuel remaining amount sensor for detecting a remaining amount of fuel stored in a fuel tank, wherein the control unit controls the fuel remaining amount. An evaporative fuel processing device set to stop the operation of the heater when the amount of water falls below a preset lower limit. 11. An evaporative fuel concentration sensor according to claim 8, wherein said evaporative fuel concentration sensor is provided in the middle of a pipe from said purge port to said intake pipe and detects the concentration of evaporative fuel. An evaporative fuel processing apparatus, wherein the controller is configured to stop the operation of the heater when the evaporative fuel concentration falls below a preset lower limit concentration. 12. The evaporative fuel processing apparatus according to claim 8, further comprising a tank internal pressure sensor for detecting an internal pressure of the fuel tank, wherein the controller controls the internal pressure of the fuel tank to a predetermined lower limit pressure. An evaporative fuel processing device set to stop the operation of the heater when the temperature falls below. 13. An evaporative fuel introduction port communicating with a fuel tank, a purge port communicating with an intake pipe of an internal combustion engine,
A canister filled with an adsorbent for adsorbing fuel vapor from a fuel tank is provided in a container formed with an atmospheric port opened to the atmospheric pressure, and air is supplied from the atmospheric port into the canister by a purge pump. An evaporative fuel treatment device configured to purge fuel desorbed from the adsorbent from a purge port to an intake pipe, wherein a metering valve configured to freely open and adjust a flow rate of the purge pump; A controller for controlling the metering valve to adjust the opening of the metering valve. 14. An evaporative fuel introduction port communicating with a fuel tank, a purge port communicating with an intake pipe of an internal combustion engine,
A canister filled with an adsorbent for adsorbing fuel vapor from a fuel tank is provided in a container formed with an atmospheric port opened to the atmospheric pressure, and air is supplied from the atmospheric port into the canister by a purge pump. An evaporative fuel processing apparatus for purging fuel desorbed from the adsorbent from a purge port to an intake pipe, comprising: a heater for heating the interior of the canister; and a control unit for controlling the purge pump and the heater. Prior to starting the operation of the purge pump,
An evaporative fuel treatment apparatus characterized in that the heater is set to operate. 15. An evaporative fuel introduction port communicating with a fuel tank, a purge port communicating with an intake pipe of an internal combustion engine,
A canister filled with an adsorbent for adsorbing fuel vapor from a fuel tank is provided in a container formed with an atmospheric port opened to the atmospheric pressure, and air is supplied from the atmospheric port into the canister by a purge pump. An evaporative fuel processing device configured to purge fuel desorbed from the adsorbent from a purge port to an intake pipe, a refueling detection sensor that detects whether or not refueling has been performed in a fuel tank; and the purge pump. And a control unit that controls the purge pump to operate when the fuel is supplied. 16. An evaporative fuel introduction port communicating with a fuel tank, a purge port communicating with an intake pipe of an internal combustion engine,
A canister in which an adsorbent for adsorbing fuel vapor from a fuel tank is sealed is provided in a container having an atmosphere port opened to the atmospheric pressure and air is supplied from the atmosphere port into the canister by a purge pump. An evaporative fuel treatment device configured to purge the fuel desorbed from the adsorbent from the purge port to the intake pipe. An evaporative fuel concentration sensor for detecting the concentration; and a control unit for controlling the purge pump. The control unit controls the purge pump to operate when the concentration of the evaporative fuel exceeds a preset purge start concentration. An evaporative fuel treatment apparatus characterized by being set. 17. An evaporative fuel introduction port communicating with a fuel tank, a purge port communicating with an intake pipe of an internal combustion engine,
A canister in which an adsorbent for adsorbing fuel vapor from a fuel tank is sealed is provided in a container having an atmosphere port opened to the atmospheric pressure and air is supplied from the atmosphere port into the canister by a purge pump. An evaporative fuel treatment device configured to purge the fuel desorbed from the adsorbent from the purge port to the intake pipe. An evaporative fuel concentration sensor for detecting the concentration, and a control unit for controlling the purge pump, wherein the control unit calculates a purge fuel amount based on a purge flow rate and a detection result of the evaporative fuel concentration sensor. An evaporative fuel processing apparatus characterized in that the purge pump is set to operate when the purge fuel amount exceeds a preset purge start fuel amount. 18. An evaporative fuel introduction port communicating with a fuel tank, a purge port communicating with an intake pipe of an internal combustion engine,
A canister in which an adsorbent for adsorbing fuel vapor from a fuel tank is sealed is provided in a container having an atmosphere port opened to the atmospheric pressure and air is supplied from the atmosphere port into the canister by a purge pump. An evaporative fuel treatment device configured to purge the fuel desorbed from the adsorbent from a purge port to an intake pipe, wherein the purge pump is provided with an impeller rotatably disposed in a pump housing and a shaft thereof. Driven by a motor connected to the end, a circular flow method is used to transmit the rotational energy of the impeller to the air flowing through the pump housing from the suction port to the discharge port, and the rotating shaft of the impeller and the motor The impeller and the rotating shaft of the motor have a structure in which the rotating shaft of the motor is slidable in the thrust direction. A structure having a non-slip portion inclined with respect to a circumferential direction centered on the motor rotation axis, and having a gap on an opposing surface in a thrust direction between the impeller and the motor rotation axis. Evaporative fuel processing device. 19. The fuel vapor processing apparatus according to claim 18, wherein bearings of the impeller are provided on both sides of the main body of the impeller. 20. A failure diagnosis device for detecting an operation abnormality of the evaporative fuel treatment device according to claim 1, wherein the control for controlling a purge valve for switching between communication and cutoff between a canister and an intake pipe. A pressure sensor for detecting a pressure in a closed space including the canister and the fuel tank formed by being blocked from an intake pipe by a purge valve and outputting a detection signal to the control unit; and a purge pump in a state in which the purge valve is closed. A pressurizing the closed space to determine the operating state of the purge pump based on a rate of increase in pressure detected by a pressure sensor. Diagnostic device. 21. The failure diagnosis device for an evaporative fuel treatment device according to claim 20, wherein the determination unit compares a pressure detected by a pressure sensor with a preset target pressure and closes a purge valve. When the operating time of the purge pump exceeds the upper limit time in a state where the detected pressure does not reach the target pressure, as compared with the upper limit time set in advance, the purge pump is determined to be abnormal. Failure diagnosis device for evaporative fuel treatment equipment.