JP5373459B2 - Control device for fuel tank system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suitably inhibit adsorption of evaporated fuel to a canister in a sealed fuel tank system. <P>SOLUTION: In the fuel tank system 800 which is a sealed fuel tank system capable of sealing a fuel tank 801 by a seal valve 809, an ECU 100 executes back purge control. In the control, the seal valve 809 is opened when tank inner pressure Ptk which is pressure in a reservoir section A of the fuel tank 801 is negative, and evaporated fuel is back purged to the fuel tank 801 from a canister 811 adsorbing the evaporated fuel through an evaporation passage 810. Consequently, adsorption of the evaporated fuel by the canister 811 can be inhibited. Since part of back purged evaporated fuel is re-liquefied and used for regular fuel injection, adsorption load of the canister 811 is reduced further. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a technical field of a control device for a fuel tank system that controls a fuel tank system including an evaporative fuel processing device.

  As this type of device, there is one that controls a sealed fuel tank system (see, for example, Patent Document 1). According to the control device for the sealed fuel tank system disclosed in Patent Document 1, it is said that the processing capability of the evaporated fuel can be improved by correcting the decrease in the throttle opening when purging the evaporated fuel. .

  In addition, in the sealed fuel tank system, there is also proposed a system in which the threshold value of the valve opening pressure of the blocking valve is changed according to the amount of canister adsorption (see, for example, Patent Document 2).

  In addition, in a sealed fuel tank system, there has been proposed a system that controls opening / closing of a canister air release valve in accordance with the internal pressure of the fuel tank at the time of purging (see, for example, Patent Document 3).

JP 2005-105896 A JP 2007-64154 A JP 2004-308483 A

  When a sealed fuel tank system capable of sealing the inside of the fuel tank with a sealing valve as disclosed in Patent Documents 1 to 3 is employed, the canister and the fuel tank can be selectively separated by the sealing valve. For this reason, it is possible to suppress the adsorption of the evaporated fuel in the canister to some extent by opening the blocking valve only when the fuel is supplied, for example.

  On the other hand, in a vehicle capable of so-called EV travel using only the power of a rotating electric machine such as a hybrid vehicle, the start frequency of the internal combustion engine tends to decrease, and in particular, a PHV (Plug-in Hybrid Vehicle) The tendency is more conspicuous in a vehicle in which EV driving can be the main driving mode. In such a vehicle, the period during which purging of the evaporated fuel into the intake passage (hereinafter referred to as “main purge” as appropriate) is reduced, and in some cases, simply performing the main purge of the internal combustion engine. It may be necessary to start the engine at the same time, which may lead to deterioration of fuel consumption.

  In other words, when the sealed fuel tank system is applied to such a case where the internal combustion engine has a low start frequency, it is necessary to more actively suppress the adsorption of the evaporated fuel to the canister. However, the various prior arts described above have no ingenuity from such a viewpoint, and there is still room for improvement.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a control device for a fuel tank system that can suitably suppress adsorption of evaporated fuel to a canister in a sealed fuel tank system.

In order to solve the above-described problems, a control device for a fuel tank system according to the present invention is mounted on a vehicle and stores a fuel tank for an internal combustion engine, and a canister that can adsorb evaporated fuel generated in the fuel tank. An evaporative fuel passage that communicates the canister and the fuel tank, a sealing valve that is installed in the evaporative fuel passage and that can open and close the evaporative fuel passage, and an intake passage of the internal combustion engine and the canister communicate with each other A control device for a fuel tank system, comprising: a purge passage to be operated; and a purge control valve installed in the purge passage and capable of opening and closing the purge passage; and a specifying means for specifying an internal pressure of the fuel tank; and control means for opening said closing valve when the specified internal pressure is negative pressure, the control means, the disengagement of the adsorbed fuel vapor Wherein the reduction in the efficiency to open the said sealing valve to fit in the allowable range.

  A vehicle according to the present invention includes an internal combustion engine as a power source and a fuel tank system having a function of processing evaporated fuel. The vehicle control device according to the present invention is a device for controlling the vehicle according to the present invention, and includes, for example, one or a plurality of CPUs (Central Processing Units), MPUs (Micro Processing Units), various processors, or various types. Various processing such as a single or multiple ECUs (Electronic Controlled Units), which may appropriately include various storage means such as a controller or ROM (Read Only Memory), RAM (Random Access Memory), buffer memory or flash memory Various computer systems such as a unit, various controllers or a microcomputer device may be used.

  The internal combustion engine according to the present invention means an engine capable of converting the combustion of fuel into mechanical power. For example, the fuel type (for example, gasoline, light oil, alcohol, alcohol mixed fuel or natural gas), the fuel There are no particular limitations on the physical, mechanical, or electrical configuration, such as the supply mode, fuel combustion mode, intake / exhaust system configuration, and cylinder arrangement.

  A fuel tank system according to the present invention is a device including at least a fuel tank, a canister, an evaporative fuel passage, a block valve, a purge passage and a purge control valve, and is a block valve installed in the vapor fuel passage This is a so-called sealed fuel tank system configured so that the fuel tank can be sealed.

  In the fuel tank system according to the present invention, the physical, mechanical and electrical configurations, structures and arrangement modes of other components that can be provided in addition to the components and the components are the functions of the fuel tank system. (1) Adsorption of evaporated fuel by canister, (2) Purging adsorbed evaporated fuel into intake passage (ie, main purge), and (3) Selective blocking of evaporated fuel passage by block valve, respectively. As long as it is, it is not intended to be limited in any way.

  According to the control device for a fuel tank system of the present invention, the internal pressure of the fuel tank (hereinafter referred to as “tank internal pressure” as appropriate) is specified by the specifying means during the operation. It should be noted that “specific” according to the present invention is a concept that comprehensively establishes the degree of authenticity as information that can be finally referred to for control, such as detection, calculation, estimation, identification, derivation, selection, and acquisition. However, the process for that purpose is not limited in any way. For example, the identification means may be various detection means such as a pressure sensor, or may be a means capable of acquiring the tank internal pressure as an electric signal or the like as a detection result from the various detection means. By selecting a corresponding value from, for example, a map or the like based on other index values, physical quantities, or control quantities that are known experimentally, empirically, theoretically or based on simulation, etc. For example, a means for estimating by performing various arithmetic processes may be used.

  According to the control apparatus for a fuel tank system according to the present invention, when the specified tank internal pressure is a negative pressure, the blocking valve is opened by the control means.

  In this type of sealed fuel tank system, the amount of fuel in the fuel tank due to the fuel supply to the fuel injection device (uniquely, change in the fuel level), the decrease in fuel temperature, etc. The tank internal pressure may decrease to a value in the negative pressure region. On the other hand, a canister that is appropriately and selectively communicated with a fuel tank via a blocking valve generally has a configuration that can communicate with the external space as appropriate by, for example, an atmosphere communication port, an atmosphere communication path, and a switching valve. Also, from the viewpoint of promoting the smooth progress of the main purge, the internal pressure is maintained at atmospheric pressure or a pressure region in the vicinity thereof when viewed constantly.

  Therefore, if the block valve is opened when the tank internal pressure is negative, an air flow is generated from the canister side to the fuel tank side, and the evaporated fuel adsorbed by the canister is returned to the fuel tank side again (note that this Hereinafter, such processing is referred to as “back purge” as appropriate). As a result, the amount of fuel vapor adsorbed in the canister decreases from the previous value.

  The main purge described above is executed in response to a purge request that may occur when, for example, the adsorption amount of the evaporated fuel in the canister reaches or approaches the adsorption limit of the canister, or reaches a certain amount, as a preferred form. Therefore, the frequency of performing the main purge is reduced by reducing the adsorption amount by the back purge of the evaporated fuel.

  Here, the main purge can be executed at all times during operation of the internal combustion engine in which a negative pressure is formed in the intake passage, but some of the combustion states including the cold start period are not good. During the operation period, the combustion state is more likely to deteriorate due to the fact that the control accuracy of the purge amount of the evaporated fuel is lower than the fuel injection accuracy. However, since the amount of evaporated fuel adsorbed in the canister can change regardless of the state of the internal combustion engine, in some cases, the main purge is required during a period when the combustion state is not good, and the result of the main purge being executed. , Emissions and drivability may deteriorate due to deterioration of the combustion state.

In this regard, according to the control device for the fuel tank system according to the present invention, the adsorption amount of the evaporated fuel in the canister is shifted to the decreasing side by the back purge, which is a process different from the main purge, and the execution frequency of the main purge is lowered. (Normally, the adsorbed evaporated fuel is not reduced except for the main purge), and the practically beneficial effect peculiar to the present invention can be achieved such that the emission and drivability of the internal combustion engine can be suitably secured. The
Here, in particular, the control device for the fuel tank system according to the present invention is configured such that the control means opens the block valve so that the decrease in the desorption efficiency of the adsorbed evaporated fuel falls within an allowable range.
When the evaporated fuel is back-purged from the canister to the fuel tank, the temperature of the activated carbon decreases due to the effect of latent heat of vaporization when the evaporated fuel is desorbed from the activated carbon, which is an adsorbent. May decrease.
However, according to the control device for a fuel tank system according to the present invention, the control means opens the block valve so that the decrease in the desorption efficiency falls within an allowable range. The amount (that is, the back purge amount) can be suitably maintained.

  Note that the back-purged evaporative fuel is liquefied not a little, depending on the installation environment of the fuel tank, and can be consumed via the fuel injection device as regular fuel. For this reason, the back purge according to the present invention is also preferable from the viewpoint of effective use of fuel.

  Supplementally, the evaporated fuel that is back-purged may be adsorbed by the canister again. However, if such re-adsorption occurs, the frequency of main purge execution is less than when back-purge is not performed. It will not change at least to the increase side, and will not cause any problems in practice.

  Moreover, the effect peculiar to the control apparatus of the fuel tank system according to the present invention is not limited to such guarantee of emission and drivability. That is, generally, maintaining the inside of the fuel tank at a negative pressure lower than the atmospheric pressure is not a good idea from the viewpoint of maintaining the quality of the fuel tank. For example, when the tank internal pressure repeatedly changes between the positive pressure or the atmospheric pressure and the negative pressure, there is a possibility that the physical durability, the sealing property, the heat insulating property, and the like of the fuel tank are deteriorated. That is, it is desirable that the tank internal pressure is also maintained at atmospheric pressure or a pressure in the vicinity thereof at least in a steady manner. In view of such circumstances, it does not matter in practice how much the canister adsorbs the evaporated fuel when the block valve is opened when the tank internal pressure is negative. Only approaching atmospheric pressure can provide very high practical benefits.

  The effect peculiar to the control device for the fuel tank system according to the present invention is conspicuous in a hybrid vehicle in which the operation frequency of the internal combustion engine is relatively low, particularly in a PHV or the like in which EV driving can be the main driving mode. That is, in the hybrid vehicle, the start frequency of the internal combustion engine can be reduced by EV traveling. Therefore, in addition to the problems such as the above-described emission and deterioration of drivability, the internal combustion engine intended only to execute the main purge is used. New problems can occur, such as start requests. Needless to say, such a start of the internal combustion engine is a useless start that directly leads to a deterioration in fuel consumption and should be avoided. In that respect, when the control device for the fuel tank system according to the present invention is applied, the frequency of purge requests can be reduced by suppressing the adsorption of the evaporated fuel in the canister. It is also possible to avoid deterioration.

  In one aspect of the control apparatus for a fuel tank system according to the present invention, the fuel tank system further includes negative pressure introducing means for introducing a negative pressure in the intake passage into the fuel tank when the internal combustion engine is in operation.

  According to this aspect, when the internal combustion engine is in operation, the negative pressure in the intake passage is introduced into the fuel tank by the negative pressure introducing means, and the above-described opportunity for performing the back purge of the evaporated fuel is forcibly provided. For this reason, it becomes possible to more actively suppress the adsorption of the evaporated fuel in the canister.

  In this aspect, the negative pressure introducing means may open the purge control valve and the blocking valve so that the negative pressure in the intake passage is introduced into the fuel tank when the internal combustion engine is operating. .

  The intake passage communicates with the canister via the purge passage, and the canister communicates with the fuel tank via the evaporated fuel passage. Therefore, by opening the purge control valve and the blocking valve installed in these passages, it becomes possible to easily introduce the negative pressure of the intake passage into the fuel tank. In addition, when existing components are used in this way, for example, it is not necessary to construct a new negative pressure introducing passage between the intake passage and the fuel tank, and it is also clear from the viewpoint of cost and vehicle mounting ability. It is advantageous. However, the negative pressure introducing means according to the present invention does not necessarily need to be a control means for controlling such existing components, and includes a novel passage specialized for negative pressure introduction as described above. May be.

  In another aspect of the control apparatus for a fuel tank system according to the present invention, the control means opens the block valve during a period when fuel supply is stopped in the internal combustion engine.

  According to this aspect, the control means uses a period in which the fuel supply is stopped, such as during fuel cut or when the engine is stopped (if the vehicle is a hybrid vehicle, the vehicle itself can be in a traveling state by EV traveling or the like). Then, the blocking valve is opened.

  During the period when the fuel supply is stopped, no negative pressure is formed in the intake pipe, or the purged fuel cannot be combusted even though physical movement of the internal combustion engine occurs due to motoring or the like. It is difficult to perform a main purge.

  According to this aspect, by performing the back purge in a period in which such main purge is substantially impossible, it is possible to more effectively receive the benefits related to the suppression of the adsorption of evaporated fuel in the canister. Become.

  In this aspect, the control means may control the blocking valve so that the opening degree of the blocking valve becomes a minimum opening degree.

  The minimum opening of the blocking valve is a substantially minimum opening defined by various physical, mechanical or electrical restrictions or control restrictions. For example, the closing valve is duty-driven. In the case of a solenoid valve or the like, the opening may correspond to a theoretical or substantially minimum duty ratio. In this case, the decrease in desorption efficiency due to vaporization latent heat is suppressed to the minimum, while the back purge executable period that can be uniquely defined by the pressure difference between the internal pressure of the canister and the internal pressure of the tank is maximized. Therefore, it is possible to secure as much back purge amount as possible, which is extremely useful in practice.

  In another aspect of the control apparatus for a fuel tank system according to the present invention, the vehicle is a hybrid vehicle including at least one rotating electric machine that functions as a power source together with the internal combustion engine.

  As described above, in a hybrid vehicle provided with a rotating electrical machine such as a motor generator in addition to an internal combustion engine as a power source, the starting frequency of the internal combustion engine is lower than at least a vehicle having only the internal combustion engine as a power source. For this reason, the opportunity to execute the main purge relatively well (that is, the opportunity to execute the main purge when the combustion state is sufficiently stable) is reduced, and the main purge is relatively performed when the internal combustion engine is started. Alternatively, the chances of having to do this increase by bothering to start the internal combustion engine when it is stopped.

  As described above, when the internal combustion engine is started in response to the execution request of the main purge, there is a high possibility that the main purge is executed during an operation period where the combustion state is not necessarily good, and the drivability and the emission are deteriorated. Inevitable. In addition, since the internal combustion engine is started at a timing that is not necessary for vehicle travel, it is difficult to avoid deterioration in fuel consumption. In view of these points, the control device for the fuel tank system according to the present invention can provide extremely high practical benefits when applied to this type of hybrid vehicle.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

1 is a schematic block diagram conceptually showing a configuration of a hybrid vehicle according to a first embodiment of the present invention. It is a schematic block diagram which represents notionally the structure of the engine and fuel supply system with which the hybrid vehicle of FIG. 1 is equipped. 2 is a flowchart of back purge control executed by an ECU in the hybrid vehicle of FIG. 1. It is a flowchart of back purge assistance control based on 2nd Embodiment of this invention. It is a flowchart of the back purge control based on 3rd Embodiment of this invention. It is a flowchart of the back purge control which concerns on 4th Embodiment of this invention. It is a flowchart of the purge control which concerns on 5th Embodiment of this invention. It is a flowchart of the purge control which concerns on 6th Embodiment of this invention.

<Embodiment of the Invention>
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<Configuration of Embodiment>
First, the configuration of the hybrid vehicle 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic block diagram conceptually showing the configuration of the hybrid vehicle 10.

  In FIG. 1, the hybrid vehicle 10 includes a speed reduction mechanism 11 and wheels 12, an ECU 100, an engine 200, a motor generator MG <b> 1 (hereinafter abbreviated as “MG1” as appropriate), and a motor generator MG2 (hereinafter abbreviated as “MG2” as appropriate). ), A hybrid vehicle as an example of the “vehicle” according to the present invention, including the power split mechanism 300, the PCU 400, the battery 500, the charging plug 600, the relay circuit 700, and the fuel tank system 800.

  The speed reduction mechanism 11 is a gear mechanism including a differential gear (not shown) and a planetary gear. The speed of the drive shaft (not shown), which is the power output shaft of the power split mechanism 300, is adjusted according to a predetermined reduction ratio. 12 is configured to be able to transmit to an axle connected to the vehicle. Note that the configuration of the speed reduction mechanism is not limited to that of the speed reduction mechanism 11, and various modes can be adopted. For example, the speed reduction mechanism may have a function as a speed change mechanism capable of realizing a plurality of shift speeds by a plurality of clutches and brakes and a planetary gear mechanism.

  The ECU 100 is an electronic control unit that includes a CPU, a ROM, a RAM, and the like and is configured to be able to control the entire operation of the hybrid vehicle 10, and is an example of the “control device for the fuel supply system” according to the present invention. The ECU 100 is configured to be able to execute various controls described later according to a control program stored in the ROM.

  The ECU 100 is an integrated electronic control unit configured to function as an example of each of the “specifying unit” and the “control unit” according to the present invention, and all the operations related to these units are executed by the ECU 100. It is comprised so that. However, the physical, mechanical, and electrical configurations of each of the units according to the present invention are not limited to this. For example, each of these units includes a plurality of ECUs, various processing units, various controllers, a microcomputer device, and the like. It may be configured as various computer systems.

  The engine 200 is a gasoline engine that is configured to function as one of the power sources of the hybrid vehicle 10 and that is an example of the “internal combustion engine” according to the present invention. The detailed configuration of the engine 200 will be described in detail later with reference to FIG.

  The motor generator MG1 is configured to function as a generator for charging the battery 500 or supplying electric power to the motor generator MG2, and further as an electric motor for assisting the power of the engine 200, according to the present invention. This is a motor generator as an example of a “rotary electric machine”.

  The motor generator MG2 is a motor generator as another example of the “rotary electric machine” according to the present invention, and serves as a motor that is one of the power sources of the hybrid vehicle 10 together with the engine 200, or a generator for charging the battery 500. Is configured to function as

  The motor generator MG1 and the motor generator MG2 are configured as, for example, a synchronous motor generator, and include a rotor having a plurality of permanent magnets on the outer peripheral surface, and a stator wound with a three-phase coil that forms a rotating magnetic field. Prepare. However, other types of motor generators may be used.

  Power split device 300 is a planetary gear mechanism configured to be able to distribute engine torque Te, which is the output power of engine 200, to MG1 and the drive shaft. In addition, since the structure of the power split mechanism 300 can take various well-known aspects, a detailed description thereof is omitted here, but in brief, the power split mechanism 300 includes a sun gear provided at the center, A ring gear concentrically provided on the outer periphery of the sun gear, a plurality of pinion gears disposed between the sun gear and the ring gear and revolving while rotating on the outer periphery of the sun gear, and coupled to an end of the crankshaft 205, And a planetary carrier that supports the rotation shaft of each pinion gear.

  The sun gear is coupled to the rotor (not shown) of the MG 1 via the sun gear shaft, and the ring gear is coupled to the rotor (not shown) of the MG 2 via the drive shaft and the speed reduction mechanism 11. The drive shaft is connected to the axle as described above, and the motor torque supplied from the MG 2 is transmitted to the axle via the drive shaft and the speed reduction mechanism 11, and is similarly transmitted to the wheel 12 via the axle. Is input to the MG 2 via the speed reduction mechanism 11 and the drive shaft. Under such a configuration, the engine torque Te is transmitted to the sun gear and the ring gear by the power carrier mechanism 300 and the pinion gear, and the engine torque Te is divided into two systems.

  At this time, the MG1 can function as a reaction force element by controlling its output torque so as to balance the engine torque Te transmitted to the sun gear, for example. For this reason, according to power split device 300, it is possible to freely control the rotational speed of engine 200 by controlling the rotational speed of MG1. Using this characteristic, in the hybrid vehicle 10, MG1 is used as a rotation speed control device of the engine 200, the operating point of the engine 200 is maintained at, for example, the optimum fuel consumption operating point, and cranking at the time of starting the engine 200 is performed. Etc. are executed.

  On the other hand, MG2 can supply the motor torque to the drive shaft independently of the supply of engine torque Te from engine 200. Therefore, the hybrid vehicle 10 can perform EV traveling using only the power of the MG2. During the EV running period, the fuel supply in the engine 200 is stopped and the motor generator MG1 is also stopped, but the engine 200 has almost zero rotational speed due to the friction, and MG1 is determined by the rotational speed of the drive shaft and the engine. It idles at a rotational speed that is uniquely determined according to the rotational speed of 200. That is, during EV traveling, the engine 200 basically stops its physical motion.

  PCU 400 converts the DC power extracted from battery 500 into AC power and supplies it to motor generator MG1 and motor generator MG2, and also converts AC power generated by motor generator MG1 and motor generator MG2 into DC power. An inverter (not shown) configured to be able to supply the battery 500 is included, and power input / output between the battery 500 and each motor generator, or power input / output between each motor generator (that is, In this case, the power control unit is configured to be capable of controlling the power transmission / reception between the motor generators without using the battery 500. The PCU 400 is electrically connected to the ECU 100, and its operation is controlled by the ECU 100.

  The battery 500 is a rechargeable storage battery configured to be able to function as a power source related to electric power for driving the motor generator MG1 and the motor generator MG2. Here, the battery 500 is configured to be appropriately chargeable by an external power source 20 installed outside the hybrid vehicle 10. That is, the battery 500 is configured to be charged not only by the power generated by the power generation action of each motor generator but also by the power supply from the external power source 20, and the hybrid vehicle 10 is configured as a so-called PHV.

  Charging plug 600 is a metal plug that is electrically connected to the input terminal of relay circuit 700 and enables electrical connection to external power supply 20. The external power source 20 may be a household 100 V power source, for example, or may be installed as an infrastructure facility in an appropriate infrastructure facility (for example, a gas station or a service station) in an urban area or a suburb. The physical, mechanical, mechanical, electrical or chemical aspects are not limited in any way.

  The relay circuit 700 is a switching circuit that can selectively and selectively switch the electrical connection state between the input terminal on the charging plug 600 side and the output terminal on the battery 500 side (in FIG. 1, connection). Not shown). The relay circuit 700 is electrically connected to the ECU 100, and the connection state is controlled by the ECU 100. When the input terminal and the output terminal are electrically connected, the battery 500 is electrically connected to the charging plug 600. When the charging plug 600 is connected to the external power source 20, The battery 500 is automatically energized halfway and charging is started. When the input terminal and the output terminal are not connected, the battery 500 is released from the charge plug 600 and charged. Regardless of whether or not is connected to the external power source 20, the power supply to the battery 500 is stopped.

  The fuel tank system 800 is a device configured to be able to supply gasoline as fuel to the engine 200. Here, the detailed configuration of the engine 200 and the fuel tank system 800 will be described with reference to FIG. FIG. 2 is a schematic configuration diagram conceptually showing the configuration of the engine 200 and the fuel tank system 800.

  In FIG. 2, an engine 200 burns an air-fuel mixture through an ignition operation by an ignition device 202 in which a part of a spark plug (not shown) is exposed in a combustion chamber in a cylinder 201, and an explosive force due to such combustion. The reciprocating motion of the piston 203 that occurs in response to the above is converted into the rotational motion of the crankshaft 205 via the connecting rod 204. Further, a crank position sensor 206 that detects a rotational position (that is, a crank angle) of the crankshaft 205 is installed in the vicinity of the crankshaft 205. The engine 200 is an in-line four-cylinder engine in which four cylinders 201 are arranged in series in a direction perpendicular to the paper surface. However, since the configurations of the individual cylinders 201 are equal to each other, in FIG. Only the cylinder 201 will be described.

  The “internal combustion engine” according to the present invention is not limited to a gasoline engine, but may be a diesel engine using light oil as a fuel or an engine capable of using a mixed fuel of alcohol and gasoline.

  In the engine 200, the air sucked from the outside passes through the intake pipe 207 and is mixed with the fuel injected from the injector 212 in the intake port 210 to become the above-mentioned air-fuel mixture. At this time, the fuel is supplied to the injector 212 by the fuel tank system 800. The form of the injection means for injecting the fuel does not have to adopt a so-called intake port injection type injector as shown in the figure. For example, the pressure of the fuel pumped by a feed pump or other low-pressure pump is further increased to a high-pressure pump. It may have a form such as a so-called direct injection injector that is configured to be capable of boosting pressure and directly injecting fuel into the high-temperature and high-pressure cylinder 201.

  The communication state between the inside of the cylinder 201 and the intake pipe 207 is controlled by opening and closing the intake valve 211. The air-fuel mixture combusted inside the cylinder 201 becomes exhaust and is led to the exhaust pipe 215 via the exhaust port 214 when the exhaust valve 213 that opens and closes in conjunction with opening and closing of the intake valve 211 is opened.

  A three-way catalyst 216 is installed in the exhaust pipe 215. The three-way catalyst 216 supports a noble metal such as platinum on a basic carrier such as alumina and has a cross section along the radial direction of the exhaust pipe 215 having a honeycomb shape, and a reduction reaction of NOx (nitrogen oxide) in the exhaust. The exhaust emission control device is configured to be able to purify the exhaust gas by causing the oxidation reaction of CO (carbon monoxide) and HC (hydrocarbon) in the exhaust gas to proceed substantially simultaneously.

  The exhaust pipe 215 is provided with an air-fuel ratio sensor 217 configured to be able to detect the exhaust air-fuel ratio of the engine 200. Furthermore, a water temperature sensor 218 for detecting the cooling water temperature related to the cooling water (LLC) circulated and supplied to cool the engine 200 is disposed in the water jacket installed in the cylinder block that houses the cylinder 201. ing.

  A throttle valve 208 that adjusts the amount of intake air related to the intake air guided through a cleaner (not shown) is disposed upstream of the intake port 210 in the intake pipe 207. The throttle valve 208 is configured such that its drive state is controlled by a throttle valve motor 209 electrically connected to the ECU 100. The throttle valve motor 209 is basically driven and controlled by the ECU 100 so that the throttle opening corresponding to the accelerator opening Ta reflecting the driver's intention is obtained. It is not always necessary to intervene (of course, it is a range that does not contradict the driver's intention), and it is possible to adjust the throttle opening automatically. That is, the throttle valve 208 is configured as a kind of electronically controlled throttle valve.

  On the other hand, in FIG. 2, the fuel tank system 800 includes a fuel tank 801. The fuel tank 801 is storage means configured to store fuel FL (that is, gasoline here) in a storage space A that is an internal space of an outer body formed of a resin material. This resin outer body is covered with a heat insulating material (not shown) so that heat exchange between the storage space A and the external space of the fuel tank 801 is eliminated as much as possible. In addition, a protector (not shown) is attached to the lower part of the fuel tank 801 so that the fuel tank 801 is not damaged by an external impact.

  In the storage space A formed inside the fuel tank 801, a pressure sensor 802 configured to detect a tank internal pressure Ptk, which is a pressure inside the fuel tank 801, is installed. The pressure sensor 802 is electrically connected to the ECU 100, and the detected tank internal pressure Pi is referred to by the ECU 100 at a constant or indefinite period.

  A fuel pump 803 is disposed inside the fuel tank 801. The fuel pump 803 is a pump device configured to be able to suck up the fuel FL from the storage space A of the fuel tank 801, and the sucked up fuel FL passes through a feed pipe 804 connected to the fuel pump 803, The fuel supply valve of the injector 212 is pressure-supplied and supplied.

  An oil supply pipe 805 is connected to the fuel tank 801 and communicates with the storage space A of the fuel tank 801 inside. At the time of refueling, the fuel cap 816 attached to the front end portion of the fuel supply pipe 805 is removed, and gasoline serving as fuel is supplied to the storage space A via the fuel supply pipe 805.

  A detection terminal of a temperature sensor 806 configured to be able to detect the fuel temperature Tf, which is the temperature of the fuel FL, is exposed below the storage space A. The temperature sensor 806 is electrically connected to the ECU 100, and the detected fuel temperature Tf is referred to by the ECU 100 at a constant or indefinite period.

  An evaporation passage 810 (that is, an example of an “evaporated fuel passage” according to the present invention) is disposed between the storage space A and a canister 811 described later. The evaporation passage 810 is further provided with a block valve 809 configured to allow the storage space A and the canister 811 to communicate with each other appropriately.

  The blocking valve 809 is a solenoid valve that uses a duty-controlled electromagnetic actuator as its driving means, and its opening degree is a fully open opening degree (for example, 100%) that opens the evaporation passage 810 and the evaporation passage 810 is closed. Between the fully closed opening (for example, 0%), it is configured to be controlled stepwise according to the drive duty ratio of the electromagnetic actuator. Hereafter, the state corresponding to the fully open position and the fully closed position will be expressed as a fully open state and a fully closed state, respectively, as appropriate.

  The blocking valve 809 is a normally closed electromagnetic valve that takes a fully closed state when not energized. That is, normally, the fuel tank 801 is blocked from communicating with a canister 811 described later by the block valve 809. The driving means for driving the blocking valve 809 is electrically connected to the PCU 400 described above, and drive control including control of the drive duty ratio is performed by the ECU 100 via the PCU 400.

  The blocking valve 809 is configured to communicate with the storage space A via a ROV (Roll Over Valve) 807 and a COV (Cut Off Valve) 808.

  The ROV 807 is a valve device configured to close when the liquid level of the fuel FL in the storage space A exceeds a predetermined position during refueling or the like. In the valve closed state, the ROV 807 and the fuel tank 801 It is configured to be able to block communication. Since the ROV 807 prevents the evaporation passage 810 and the fuel tank 801 from communicating with each other when the vehicle falls or the like, in the fuel tank system 800, the fuel FL does not leak to the outside through the evaporation passage 810. Absent.

  The COV 808 is arranged in parallel with the ROV 807 and is configured to be able to block communication between the evaporation passage 810 and the fuel tank 801 in accordance with the liquid level position of the fuel FL, like the ROV 807. The COV 808 maintains the open state even after the ROV 807 is closed when the liquid level rises during refueling, but it closes when the liquid level reaches the COV 808 due to the fluctuation of the liquid level due to turning of the vehicle or the like. The communication between the evaporation passage 810 and the fuel tank 801 is blocked, and the fuel FL does not leak to the outside through the evaporation passage 810.

  The canister 811 is an evaporative fuel adsorbing means provided with an adsorbent 812 made of activated carbon capable of adsorbing and holding evaporative fuel. The canister 811 is connected to three types of pipes, the evaporation passage 810, the atmosphere communication pipe 813, and the purge pipe 814 described above.

  The atmosphere communication pipe 813 is a tubular member that communicates with the space outside the vehicle of the hybrid vehicle 10. The atmosphere communication pipe 813 is provided with an atmosphere release valve 817. The air release valve 817 is a valve device having a valve body that allows the canister 811 and the vehicle exterior space to communicate with each other when the valve is opened and that the canister 811 can be separated from the vehicle exterior space when the valve is closed. The valve body drive device is electrically connected to the ECU 100, and the atmosphere release valve 817 is configured such that its drive state is controlled by the ECU 100.

  One end of the purge pipe 814 is connected to the lower side of the canister 811 and the other end is connected to the downstream side (cylinder side) of the throttle valve 208 of the intake pipe 207, which is an example of the “purge passage” according to the present invention. This is a passage of the main purge gas.

  Here, the “main purge gas” is a mixture of the outside air appropriately guided through the atmosphere communication pipe 813 when the atmosphere release valve 817 is opened and the evaporated fuel adsorbed and held by the adsorbent 812 (the amount of evaporated fuel adsorbed). Is zero, that is, the outside air itself), the main purge gas is supplied to the intake pipe 207 via the purge pipe 814 during a part of the operation period of the engine 200, and the main purge (that is, the evaporated fuel is removed). (Processing to return to the intake pipe 207).

  The purge control valve 815 is an electromagnetic valve that is installed on the purge pipe 814 and is an example of the “purge control valve” according to the present invention. The purge control valve 815 is continuously controlled by an electromagnetic actuator (not shown) between a fully opened opening for opening the purge pipe 814 and a fully closed opening for closing the purge pipe 814. It is the composition which becomes. A drive device (not shown) that drives the electromagnetic actuator is electrically connected to the ECU 100 and is driven according to control by the ECU 100. That is, the purge control valve 815 is configured to be controlled in its open / closed state by the ECU 100.

<Operation of Embodiment>
<Basic control of fuel tank system 800>
The fuel tank system 800 has a function as an evaporative fuel processing apparatus that processes evaporative fuel in addition to the function of storing the fuel FL. Hereinafter, basic control modes of the fuel tank system 800 will be described.

<When refueling>
When the fuel lid switch provided in the passenger compartment is operated by the driver of the hybrid vehicle 10 or the like, the fuel lid located further outside the fuel cap 816 in FIG. 2 is unlocked, the fuel lid is opened, and the fuel cap 816 appears. . The fuel cap 816 is configured to be manually removable, and by removing the fuel cap 816, the fuel can be supplied through the oil supply pipe 805.

  Here, the tank internal pressure Ptk which is the pressure of the storage space A of the fuel tank 801 is a positive pressure equal to or higher than the atmospheric pressure (in this embodiment, the tank internal pressure Ptk is represented by a gauge pressure based on the atmospheric pressure. That is, a pressure below atmospheric pressure is a negative pressure, and a pressure higher than atmospheric pressure is a positive pressure, but “atmospheric pressure” does not necessarily need to be an atmospheric pressure in a strict sense, If the fuel cap 816 is removed, the evaporated fuel will be discharged from the storage space A to the outside unless any countermeasure is taken.

  Therefore, when the ECU 100 receives an operation signal indicating that the fuel lid switch has been operated as an electrical signal, the ECU 100 energizes the block valve 809 via the PCU 400 to control the block valve 809 to be fully opened. At the same time, the atmosphere release valve 817 is controlled to open, and the inside of the canister 811 is communicated with the atmosphere.

  When such valve control is performed, if the tank internal pressure Ptk is positive due to the evaporated fuel, the evaporated fuel in the storage space A is guided to the canister 811 via the evaporation passage 810 and is adsorbed and held by the adsorbent 812. Is done. Clean air after passing through the canister 811, in which all the evaporated fuel is adsorbed by the adsorbent 812, is discharged out of the vehicle through the atmosphere communication pipe 813 through the atmosphere release valve 817 in the valve open state. As a result, the tank internal pressure Ptk decreases to approximately atmospheric pressure.

  The ECU 100 releases the lock of the fuel lid after confirming from the sensor value of the pressure sensor 802 that the storage space A has dropped to near atmospheric pressure. Such control logic prevents the evaporative fuel from being released from the vehicle during refueling.

  While the refueling is continued, the tank internal pressure Ptk increases as the fuel level rises, so the block valve 809 is maintained in the open state. When refueling is completed, the fuel cap 816 is attached, and the fuel lid is closed, the ECU 100 stops energization to the sealing valve 809 after locking the fuel lid. In conjunction with this, the air release valve 817 is also closed.

<When main purge is executed>
When the amount of evaporated fuel adsorbed in the canister 811 (adsorbed amount of the adsorbent 812) exceeds a certain level, a main purge execution request is generated.

  Here, if all of the evaporated fuel guided to the canister 811 when the blocking valve 809 is opened is adsorbed by the adsorbent 812 of the canister 811, the evaporated fuel is determined based on the tank internal pressure Ptk and the fuel temperature Tf. It is possible to estimate the amount of adsorption. In this embodiment, an adsorption speed map in which the tank internal pressure Ptk, the fuel temperature Tf and the adsorption speed of the evaporated fuel are associated with each other is stored in advance in the ROM, and the ECU 100 detects the tank internal pressure Ptk detected by the pressure sensor 802. And the fuel temperature Tf detected by the temperature sensor 806, the adsorption speed of the evaporated fuel is acquired at a constant period, and the acquired adsorption speed is integrated during the valve-opening period of the blocking valve 809, whereby the canister The amount of evaporated fuel adsorbed at 811 is estimated.

  Note that such an estimation mode of the adsorption amount is merely an example, and various known modes can be employed for estimating the adsorption amount. For example, a detection unit configured to directly detect the amount of evaporated fuel adsorbed in the canister 811 may be attached to the canister 811 so that the detection result can be referred to by the ECU 100 at a constant or indefinite period. .

  The main purge execution request is generated when the estimated adsorption amount reaches a reference value set in a range less than the adsorption amount corresponding to the saturated state of the adsorbent 812. When the main purge execution request is generated, if engine 200 is in operation, ECU 100 controls blockade valve 809 to a fully closed state and atmospheric release valve 817 to a fully open state, and sets purge control valve 815 to a predetermined value. The valve is controlled to open by opening.

  On the other hand, when the engine 200 is in an operating state, a negative pressure is formed mainly in the intake stroke on the downstream side of the throttle valve 208 in the intake pipe 207. Therefore, when the engine 200 is in an operating state, by maintaining the purge control valve 815 in the open state, the outside air is guided to the canister 811 by the engine negative pressure through the atmosphere communication pipe 813, and the outside air is purged. In the course of reaching the pipe 814, the fuel is appropriately mixed with the evaporated fuel held in the adsorbent 812, so that the main purge gas is supplied to the intake pipe 207 via the purge pipe 814. That is, the main purge is executed.

  If the engine 200 is not in operation when a main purge execution request is made, the ECU 100 starts the engine 200 to execute the main purge, and executes the main purge as described above. However, in the fuel tank system 800, as described above, the block valve 809 is basically kept closed except during refueling, and the fuel tank 801 is sealed. For this reason, the adsorption of the evaporated fuel to the canister 811 is remarkably limited, and the frequency at which the adsorbed amount of the evaporated fuel in the canister 811 reaches the reference value is not high.

<Details of back purge control>
The fuel tank system 800 is a so-called sealed fuel tank system, and as described above, the adsorption of the evaporated fuel in the canister 811 is preferably suppressed. In the present embodiment, the fuel tank system 800 is controlled by the back purge control executed by the ECU 100. Adsorption of the evaporated fuel is further preferably suppressed. The fact that the adsorption of the evaporated fuel is further suppressed means that the frequency of execution of the main purge request is further reduced, and inevitably the main purge at the cold start in which the combustion state is not good or the main purge. This means that the engine start for the engine is suppressed. That is, it is possible to suppress the deterioration of drivability, emission, and fuel consumption, which is extremely beneficial in practice.

  Here, the details of the back purge control will be described with reference to FIG. FIG. 3 is a flowchart of the back purge control.

  In FIG. 3, the ECU 100 determines whether or not the tank internal pressure Ptk, which is the pressure inside the fuel tank 801 (that is, the storage space A), is a negative pressure (step S101).

  Since the fuel tank system 800 is a sealed fuel tank system in which the fuel tank 801 is covered with a heat insulating material, for example, when the fuel temperature Tf decreases while the fuel amount remains constant, the tank internal pressure Ptk decreases. Further, when the amount of stored fuel FL decreases due to the fuel supply via the injector 212, the tank internal pressure Ptk inevitably decreases. That is, the tank internal pressure Ptk becomes a negative pressure with a small frequency.

  When the tank internal pressure Ptk is atmospheric pressure or positive pressure (step S101: NO), the ECU 100 repeats the process related to step S101. On the other hand, when the tank internal pressure Ptk is a negative pressure (step S101: YES), the ECU 100 opens the block valve 809 (step S102). At this time, the purge control valve 815 is closed and the air release valve 817 is opened.

  When the valves are controlled in this way, the back purge gas (mainly described above) which is a mixed gas of the evaporated fuel adsorbed in the storage space A and the outside air via the atmospheric communication path 813, the canister 811 and the evaporation path 810 is provided. Is substantially equal to the purge gas), and a back purge of the evaporated fuel is realized. That is, the evaporated fuel originally present in the storage space A is returned to the storage space A again.

  When the blocking valve 809 is opened, the ECU 100 determines whether or not the tank internal pressure Ptk has reached atmospheric pressure (step S103). If the tank internal pressure Ptk is still a negative pressure (step S102: NO), the ECU 100 maintains the block valve 809 in the open state, and when the tank internal pressure Ptk reaches the atmospheric pressure (step S102: YES), the ECU 100 The blocking valve 809 is closed (step S104).

  At the same time as the closing valve 809 is closed, the air release valve 817 is also closed. When step S104 is executed, the process returns to step S101 again, and a series of processes is repeated. The back purge control is performed as described above.

  Thus, according to the back purge control, if the tank internal pressure Ptk is a negative pressure, the evaporated fuel can be desorbed from the adsorbent 812 using the negative pressure. For this reason, it is possible to suppress an increase in the amount of evaporated fuel adsorbed in the canister 811 and to reduce the frequency at which a main purge execution request is generated. At this time, a part of the evaporated fuel returned to the fuel tank 801 can be liquefied and used for normal fuel injection. Therefore, not only can the load on the canister 811 be temporarily reduced by back purge, but also the canister The absolute load of 811 can be reduced.

  Further, the phenomenon that the storage space A is maintained at a negative pressure or the tank internal pressure Ptk fluctuates between a positive pressure and a negative pressure is at least from the viewpoint of ensuring the durability and reliability of the fuel tank 801. Not desirable.

  In that respect, according to the back purge according to the present embodiment, the adsorption of the evaporated fuel in the canister 811 is suppressed, and at the same time the durability of the fuel tank 801 is maintained by maintaining the storage space A at a pressure state approximately equal to or higher than atmospheric pressure. In addition, it is possible to improve reliability and is useful in practice.

  In this embodiment, the atmosphere release valve 817 is opened during back purge, but the canister 811 is basically maintained in a pressure state near atmospheric pressure at all times, and the atmosphere release valve 817 is closed. Even if it is said, the execution of the back purge is not hindered. In view of this point, the air release valve 817 may be maintained in the closed state when the back purge is performed.

It should be noted that the amount of evaporated fuel back purged into the fuel tank 801 is the tank internal pressure Ptk (that is, correlated with the flow rate of the back purge gas) if the canister 811 is at atmospheric pressure, and the evaporated fuel desorption from the adsorbent 812. It can be estimated by the efficiency and the execution time of the back purge. The ECU 100 updates the adsorption amount as appropriate by subtracting the estimated back purge amount from the adsorption amount of the evaporated fuel in the canister 811 described above. As a result, the frequency of occurrence of main purge execution requests decreases.
Second Embodiment
In the back purge control according to the first embodiment, in order to back purge the evaporated fuel from the canister 811, the tank internal pressure Ptk needs to be a negative pressure. As described above, in the fuel tank system 800, the possibility that the inside of the fuel tank 801 is in a negative pressure state is not low, but the inside of the fuel tank 801 can also be negatively positive. Here, with reference to FIG. 4, the back purge assist control according to the second embodiment of the present invention based on such a purpose will be described. FIG. 4 is a flowchart of the back purge assist control.

  In FIG. 4, the ECU 100 determines whether or not the main purge described above is being executed (step S201). When the main purge is not executed (step S201: NO), the back purge assist control is ended.

  When the main purge is being executed (step S201: YES), the ECU 100 determines whether or not the tank internal pressure Ptk is less than a reference value Ptk1 set in the positive pressure region (step S202). The reference value Ptk1 is an adaptive value obtained experimentally in advance, so that the pressure difference from the intake pipe 207 in the negative pressure region does not become excessively large (that is, the intake pipe 207 via the purge pipe 214). Is determined so that the amount of gas introduced into the range does not manifest the deterioration of the combustion state. When the tank internal pressure Ptk is equal to or higher than the reference value Ptk1 (step S202: NO), the ECU 100 ends the back purge assist control for the purpose of avoiding instability of the combustion state.

  When the tank internal pressure Ptk is less than the reference value Ptk1 (step S202: YES), the ECU 100 closes the air release valve 817 (step S203), opens the block valve 809 (step S204), and performs purge control. The valve 815 is forcibly opened (step S205). As a result, the negative pressure of the intake pipe 207 is introduced into the fuel tank 801.

  When negative pressure is introduced into the storage space A, the ECU 100 determines whether or not the tank internal pressure Ptk is less than the reference value Ptk2 (Ptk2 <Ptk1) (step S206). The reference value Ptk2 is a value in the negative pressure region of about −5 kPa, for example. The ECU 100 continues to introduce negative pressure into the storage space A while the tank internal pressure Ptk is equal to or higher than the reference value Ptk2 (step S206: NO), and when the tank internal pressure Ptk becomes less than the reference value Ptk2 (step S206). S206: YES), the blocking valve 809 is closed (step S207). Simultaneously with the closing control of the blocking valve 809, the air release valve 817 is opened (step S208), and the purge control valve 815 is returned to the normal driving state (step S209). The back purge assist control is executed as described above.

  As described above, according to the back purge assist control, the intake pipe negative pressure at the time of main purge execution is stored in the storage space A in addition to the passive decrease in the tank internal pressure Ptk, such as the decrease in the fuel temperature Tf and the decrease in the fuel amount. By guiding, the storage space A can be actively shifted to negative pressure (that is, in the present embodiment, the ECU 100 also functions as an example of “negative pressure introducing means” according to the present invention).

For this reason, the chance that the determination process of step S101 in the back purge control shown in the first embodiment branches to the “YES” side increases, and the back purge of the evaporated fuel is executed more frequently. That is, it is possible to further suppress the adsorption of the evaporated fuel in the canister 811.
<Third Embodiment>
Next, back purge control different from the first embodiment will be described as a third embodiment of the present invention with reference to FIG. FIG. 5 is a flowchart of the back purge control according to the third embodiment. In the figure, the same reference numerals are given to the same portions as those in FIG. 3, and the description thereof is omitted. Moreover, the structure of the vehicle which concerns on 3rd Embodiment shall be the same as 1st Embodiment.

  In FIG. 5, when the tank internal pressure Ptk is a negative pressure (step S101: YES), the ECU 100 determines whether or not the engine 200 is in a fuel cut state (step S301). If engine 200 is not in the fuel cut state (step S301: NO), ECU 100 further determines that hybrid vehicle 10 is in EV travel using only the motor torque supplied from motor generator MG2, or engine 200 is intermittently stopped. It is determined whether it is in the middle (step S302). When the hybrid vehicle 10 is not traveling in EV and the engine 200 is not intermittently stopped (step S302: NO), the ECU 100 further determines whether or not the hybrid vehicle 10 is in a soaked state (step S303). The “soak state” refers to a ready-off state in which no start input of the hybrid vehicle 10 is generated (that is, a state in which all power sources are stopped), for example, a long-time parking state. When hybrid vehicle 10 is not in the soak state (step S303: NO), ECU 100 returns the process to step S101.

  On the other hand, whether engine 200 is in a fuel cut state (step S301: YES), whether hybrid vehicle 10 is in an EV traveling state or engine 200 is intermittently stopped (step S302: YES), or hybrid vehicle 10 is soaked When the ECU 100 is in the state (step S303: YES), the ECU 100 opens the block valve 809 and executes the back purge of the evaporated fuel as in the first embodiment (step S102). The back purge control according to the third embodiment is executed as described above.

As described above, according to the back purge control according to the third embodiment, the back purge of the evaporated fuel is performed in a period in which the main purge is not performed. Therefore, the execution period overlaps between the main purge and the back purge. It is efficient.
<Fourth embodiment>
Next, back purge control different from the first and third embodiments will be described as a fourth embodiment of the present invention with reference to FIG. FIG. 6 is a flowchart of the back purge control according to the fourth embodiment. In the figure, the same reference numerals are given to the same portions as those in FIG. 3, and the description thereof is omitted. The configuration of the vehicle according to the fourth embodiment is the same as that of the first embodiment.

  In FIG. 5, when the tank internal pressure Ptk is a negative pressure (step S101: YES), the ECU 100 controls the drive duty ratio of the electromagnetic actuator that drives the block valve 809 to the minimum value, and sets the block valve 809 to the minimum duty ratio. Drive (step S401). As a result, the blocking valve 809 is maintained at the minimum opening within the range of realistic restrictions.

  According to this embodiment, since the opening degree of the blocking valve 809 at the time of back purge execution is maintained at the minimum opening degree, the flow rate per unit time of the back purge gas can be suppressed to the minimum. By slowing the progress of the back purge in this way, the desorption amount of the evaporated fuel from the adsorbent 812 per unit time is suppressed to a certain amount or less, and the temperature decrease of the adsorbent 812 due to the latent heat of vaporization is reduced It becomes possible to prevent inefficiency of the back purge caused by reducing the fuel desorption efficiency.

  At this time, by setting the opening degree of the blocking valve 809 to the minimum opening degree, the execution time of the back purge can be relatively long. However, there is almost no time restriction in executing the back purge from the beginning. However, there is almost no practical penalty for the longer execution time. That is, only the practical benefit of reducing the adsorption amount of the evaporated fuel in the canister 811 to the maximum is enjoyed.

In this embodiment, in order to suppress a decrease in the evaporative fuel desorption efficiency in the adsorbent 812, the electromagnetic actuator of the blocking valve 809 is driven at the minimum driving duty ratio, so that the blocking valve 809 is substantially Although controlled to the minimum opening, the opening of the blocking valve 809 that can keep the decrease in the evaporative fuel desorption efficiency in the adsorbent 812 within an allowable range is not necessarily limited to the minimum opening.
<Fifth Embodiment>
The back purge and the main purge can be executed in cooperation with each other by appropriately assigning priorities according to the operating conditions of the hybrid vehicle 10. Here, with reference to FIG. 7, the purge control for emphasizing these will be described as a fifth embodiment of the present invention. FIG. 7 is a flowchart of purge control. In the figure, the same reference numerals are given to the same portions as those in FIG. 3, and the description thereof is omitted. The configuration of the vehicle according to the fifth embodiment is the same as that of the first embodiment.

  In FIG. 7, when the tank internal pressure Ptk is not a negative pressure (step S101: NO), the ECU 100 determines whether or not there is a main purge execution request (step S503). If there is no main purge execution request (step S503: NO), the process returns to step S101. On the other hand, when there is a main purge request (step S503: YES), the ECU 100 executes main purge. That is, when the tank internal pressure Ptk is atmospheric pressure or positive pressure, normal main purge is executed.

  On the other hand, when the tank internal pressure Ptk is a negative pressure (step S101: YES), the ECU 100 determines whether or not there is a main purge execution request as in step S503 (step S501). When there is no main purge execution request (step S501: NO), the ECU 100 opens the block valve 809 and executes the back purge (step S102).

  Here, when there is a main purge execution request (step S501: YES), the ECU 100 determines whether or not the engine 200 is in a cold state (step S502). If engine 200 is in the warm state (step S502: NO), ECU 100 executes the main purge in preference to the back purge (step S504), and if engine 200 is in the cold state (step S502: YES). The ECU 100 executes the back purge in preference to the main purge (step S102).

As described above, according to the purge control according to the present embodiment, when there is a main purge execution request in a situation where the back purge is possible, the back purge is performed if the engine 200 is in the cold state, and the engine 200 is warm. If it is in the state, the main purge is executed with priority over one of the purges. For this reason, the main purge in the cold state where the combustion state is not good is reliably avoided, and the evaporated fuel is reliably processed in a situation where the evaporated fuel can be combusted without problems in practice. That is, it is possible to appropriately process the evaporated fuel while suppressing deterioration of drivability, emission, and fuel consumption.
<Sixth Embodiment>
Next, referring to FIG. 8, as a sixth embodiment of the present invention, a description will be given of a manner of assigning priorities different from that of the fifth embodiment. FIG. 8 is a flowchart of the purge control according to the sixth embodiment. In the figure, the same reference numerals are given to the same portions as those in FIG. 7, and the description thereof is omitted. The configuration of the vehicle according to the sixth embodiment is the same as that of the first embodiment.

  In FIG. 8, when there is a main purge execution request in step S501 (step S501: YES), the ECU 100 determines whether or not the fuel tank 801 is immediately after refueling and the remaining amount of fuel is large (step S601). ).

  Note that “immediately after refueling” means that the elapsed time after refueling (after the fuel lid is locked) is less than a preset reference value. Further, “the remaining amount of fuel is large” means that the remaining amount of fuel is, for example, about 90 to 100 with the remaining amount at the time of full tank refueling being 100, and the space volume of the storage space A is evaporated fuel. This corresponds to a state that is small enough that liquefaction of the evaporated fuel can be promoted when the back purge is performed. The remaining amount of fuel is detected by a float-type liquid level detection sensor or the like (not shown in FIG. 2), and the ECU 100 appropriately refers to it.

  If it is not immediately after refueling or if the remaining amount of fuel is not large (step S601: NO), the ECU 100 proceeds with the process to step S504, executes main purge, and immediately after refueling and if the remaining amount of fuel is large (step S601: YES), the ECU 100 opens the block valve 809 and back-purges because the space volume of the storage space A is small, the formation of negative pressure is easy, and the liquefaction of the back-purged evaporated fuel can be promoted. Is executed (step S102).

  As described above, according to the purge control according to the present embodiment, even if a main purge execution request is generated, conditions under which back purge can be effectively performed (conditions in which negative pressure is easily formed and liquefaction is likely to proceed). ) Is satisfied, the back purge is prioritized. For this reason, the adsorption suppression effect of the evaporated fuel in the canister 811 by the back purge is exhibited extremely efficiently. Note that the purge control according to the sixth embodiment and the purge control according to the fifth embodiment are not incompatible with each other, and of course, both may be used in combination.

  In the first to sixth embodiments, an example in which the control device for the fuel tank system according to the present invention is consistently applied to a hybrid vehicle is shown, but the control device for the fuel tank system according to the present invention is shown. The applicable vehicle is not limited to a hybrid vehicle, and may be a vehicle including only the engine 200 as a power source, for example.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. The control device is also included in the technical scope of the present invention.

  The present invention is applicable to a vehicle equipped with a sealed fuel tank system, for example.

  DESCRIPTION OF SYMBOLS 10 ... Hybrid vehicle, 100 ... ECU, 200 ... Engine, 201 ... Cylinder, 203 ... Piston, 205 ... Crankshaft, 300 ... Power split mechanism, 400 ... PCU, 500 ... Battery, 600 ... Charging plug, 700 ... Relay circuit, DESCRIPTION OF SYMBOLS 800 ... Fuel supply system, 801 ... Fuel tank, 802 ... Pressure sensor, 806 ... Temperature sensor, 809 ... Sealing valve, 810 ... Evaporative passage, 811 ... Canister, 812 ... Adsorbent, 813 ... Atmospheric communication pipe, 814 ... For purge Piping, 815 ... Purge control valve.

Claims (12)

Mounted on the vehicle,
A fuel tank for storing fuel of the internal combustion engine;
A canister capable of adsorbing evaporated fuel generated inside the fuel tank;
An evaporative fuel passage communicating the canister and the fuel tank;
A sealing valve installed in the evaporative fuel passage and capable of opening and closing the evaporative fuel passage;
A purge passage communicating the intake passage of the internal combustion engine and the canister;
A control device for a fuel tank system, comprising a purge control valve installed in the purge passage and capable of opening and closing the purge passage;
Specifying means for specifying the internal pressure of the fuel tank;
Control means for opening the blocking valve when the specified internal pressure is a negative pressure, and
The control means opens the block valve so that a decrease in the desorption efficiency of the adsorbed evaporated fuel is within an allowable range.
A control device for a fuel tank system. 2. The fuel tank system control device according to claim 1, further comprising a negative pressure introduction unit that introduces a negative pressure of the intake passage into the fuel tank when the internal combustion engine is operating. 3. 3. The negative pressure introducing means opens the purge control valve and the block valve so that a negative pressure in the intake passage is introduced into the fuel tank when the internal combustion engine is in operation. The fuel tank system control device described. 4. The fuel tank system control device according to claim 1, wherein the control unit opens the block valve during a period in which fuel supply is stopped in the internal combustion engine. 5. The control device for a fuel tank system according to any one of claims 1 to 4, wherein the control means controls the block valve so that an opening degree of the block valve becomes a minimum opening degree. The control device for a fuel tank system according to any one of claims 1 to 6, wherein the vehicle is a hybrid vehicle including at least one rotating electric machine that functions as a power source together with the internal combustion engine.   Mounted on the vehicle,
  A fuel tank for storing fuel of the internal combustion engine;
  A canister capable of adsorbing evaporated fuel generated inside the fuel tank;
  An evaporative fuel passage communicating the canister and the fuel tank;
  A sealing valve installed in the evaporative fuel passage and capable of opening and closing the evaporative fuel passage;
  A purge passage communicating the intake passage of the internal combustion engine and the canister;
  A purge control valve installed in the purge passage and capable of opening and closing the purge passage;
  A fuel tank system control device comprising:
  Specifying means for specifying the internal pressure of the fuel tank;
  Control means for opening the blocking valve when the specified internal pressure is a negative pressure;
  Negative pressure introducing means for introducing the negative pressure of the intake passage into the fuel tank so that the negative pressure inside the fuel tank is less than a predetermined value when the internal combustion engine is operating;
  A control apparatus for a fuel tank system comprising:   The negative pressure introducing means is configured such that a negative pressure in the intake passage is applied to the fuel tank during operation of the internal combustion engine.
Open the purge control valve and the block valve so as to be introduced
  The fuel tank system control apparatus according to claim 7.   The control means opens the block valve during a period when fuel supply is stopped in the internal combustion engine.
  9. The fuel tank system control apparatus according to claim 7 or 8,   The control means opens the block valve so that a decrease in the desorption efficiency of the adsorbed evaporated fuel is within an allowable range.
  The fuel tank system control device according to any one of claims 7 to 9, wherein the control device is a fuel tank system control device.   The control means controls the blocking valve so that the opening of the blocking valve becomes a minimum opening.
  The control device for a fuel tank system according to claim 10.   The vehicle is a hybrid vehicle including at least one rotating electric machine that functions as a power source together with the internal combustion engine.
  The control device for a fuel tank system according to any one of claims 7 to 11, wherein:

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