Patent Publication Number: US-10328804-B2

Title: Vehicle and control method for vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a divisional application based on U.S. patent application Ser. No. 14/409,605, filed Dec. 19, 2014, which is a national phase application based on the PCT International Patent Application No. PCT/IB2013/001754 filed Aug. 12, 2013, claiming priority to Japanese Patent Application No. 2012-184176 filed Aug. 23, 2012, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a technique for supplying power from a power generation apparatus that uses an engine as a power source or power from a storage apparatus to a power supply subject outside a vehicle. 
     2. Description of Related Art 
     Japanese Patent Application Publication No. 2000-234539 (JP-2000-234539 A), for example, discloses a control apparatus for a hybrid vehicle that performs power generation using a generator by controlling an engine rotation speed such that an engine is driven at or above a predetermined catalyst activation temperature in a case where power is supplied to the outside of the vehicle from an external outlet. 
     SUMMARY OF THE INVENTION 
     In the hybrid vehicle disclosed in JP-2000-234539 A, the engine may be driven in order to maintain the catalyst activation temperature even when an amount of power used by a power supply destination is small or a device at the power supply destination is temporarily stopped during an intermittent operation, and as a result, fuel may be consumed wastefully. 
     The invention provides a vehicle and a control method for the vehicle with which an engine is controlled appropriately in accordance with an operating condition of a power supply destination. 
     A vehicle according to a first aspect of the invention includes: an engine; a storage apparatus capable of supplying power to a power supply subject outside the vehicle; a power generation apparatus capable of supplying power to the power supply subject using the engine as a power source; and a control apparatus configured to operate the engine in accordance with a condition of the vehicle during a power supply operation in which power is supplied to the power supply subject from at least one of the power generation apparatus and the storage apparatus. The control apparatus is configured to suppress an operation of the engine when a power supply remains continuously smaller than a predetermined value. The power supply is the power supplied to the power supply subject during the power supply operation. 
     In the vehicle, the control apparatus may be configured to stop the operation of the engine or prohibit the engine from operating when a duration of a condition in which the power supply is smaller than the predetermined value exceeds a first time. 
     In the vehicle, the control apparatus may, be configured to stop a system of the vehicle that is activated during the power supply operation when the duration exceeds a second time, and the second time may be longer than the first time. 
     In the vehicle, the control apparatus may be configured to stop a system of the vehicle that is activated during the power supply operation when a remaining capacity of the storage apparatus falls below a threshold, and the threshold employed when the power supply remains continuously smaller than the predetermined value may be equal to or larger than the threshold employed when the power supply is larger than the predetermined value or when the duration is equal to or shorter than the first time. 
     In the vehicle, the control apparatus may be configured to permit the engine to operate when the power supply is equal to or larger than the predetermined value or when the duration is equal to or shorter than the first time. 
     In the vehicle, in a case where the power supply is equal to or larger than the predetermined value or a case where the duration is equal to or shorter than the first time, the control apparatus may be configured to permit the engine to operate when a remaining capacity of the storage apparatus falls below a threshold. 
     In the vehicle, in a case where the power supply is equal to or larger than the predetermined value or a case where the duration is equal to or shorter than the first time, the control apparatus may be configured to permit the engine to operate when a catalyst temperature of the engine falls below a threshold. 
     A second aspect of the invention relates to a control method for a vehicle. The vehicle includes an engine, a storage apparatus, and a power generation apparatus. The control method includes: operating the engine in accordance with a condition of the vehicle during a power supply operation in which power is supplied to a power supply subject outside the vehicle from at least one of the power generation apparatus and the storage apparatus, the power generation apparatus being capable of supplying power to the power supply subject using an engine as a power source, and the storage apparatus being capable of supplying power to the power supply subject; and suppressing an operation of the engine when a power supply remains continuously smaller than a predetermined value, the power supply being the power supplied to the power supply subject during the power supply operation. 
     According to the invention, the operation of the engine is suppressed when the power supply remains continuously smaller than the predetermined value during the power supply operation. Therefore, the operation of the engine is suppressed even when an operation of the engine is requested due to a reduction in the catalyst temperature or the like, for example. As a result, wasteful fuel consumption can be avoided. It is therefore possible to provide a vehicle and a control method for the vehicle with which an engine is controlled appropriately in accordance with operating conditions of a power supply destination. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
         FIG. 1  is a view showing a power supply connector attached to a vehicle with an electric device connected thereto; 
         FIG. 2  is a side view of the power supply connector; 
         FIG. 3  is an enlarged view showing a part of the power supply connector into which a plug of the electric device is inserted; 
         FIG. 4  is an overall block diagram of the vehicle according to this embodiment; 
         FIG. 5  is a view showing a first modified example of the power supply connector; 
         FIG. 6  is a view showing a second modified example of the power supply connector; 
         FIG. 7  is a block diagram showing functions of an electronic control unit (ECU) installed in the vehicle according to this embodiment; and 
         FIG. 8  is a flowchart showing a control structure of a program executed by the ECU installed in the vehicle according to this embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     An embodiment of the invention will be described below with reference to the drawings. In the following description, identical components have been allocated identical reference symbols. Names and functions thereof are also identical. Accordingly, detailed description of these components will not be repeated. 
     As shown in  FIG. 1 , a vehicle  100  is provided with an inlet  220 . One end of a connector used exclusively for supplying power (to be referred to hereafter as a power supply connector)  600  that can be attached to and detached from the vehicle  100  is attached to the inlet  220 . A socket  610  that can be connected to a plug  710  connected to a household electric device  700  (to be referred to simply as the electric device  700  hereafter) such as a rice cooker is provided on another end of the power supply connector  600 . 
     When the power supply connector  600  is connected to the inlet  220  and the plug  710  of the electric device  700  is connected to the power supply connector  600 , a power supply operation is executed in the vehicle  100 . By executing the power supply operation, power from the vehicle  100  is supplied to the electric device  700  serving as a power supply subject via the inlet  220 , the power supply connector  600 , and the plug  710 . 
     Hence, as a result of the power supply operation, the electric device  700  such as a rice cooker connected to the power supply connector  600  can be operated by power stored in a storage apparatus or the like of the vehicle  100  or power generated in a power generation apparatus, to be described below, which uses an engine as a power source. 
     The power supply connector  600  is provided with an operating member  615 . The power supply connector  600  can be detached from the inlet  220  by pressing the operating member  615 . 
       FIG. 2  is a side view of the power supply connector  600 . In  FIG. 2 , the power supply connector  600  includes a main body portion  633  provided with a connecting portion  631 , and a main body portion  634  provided with the socket  610 . 
     The connecting portion  631  that is connected to the inlet  220  of the vehicle  100 , and a pawl portion  635  provided to catch on a recess formed in the inlet  220  when the power supply connector  600  is attached to the inlet  220  are provided on one end of the main body portion  633 . The main body portion  633  includes a rod-shaped member that extends in a horizontal direction. The operating member  615  for releasing an engagement between the pawl portion  635  and the inlet  220  is provided on an upper portion of the main body portion  633 . 
     The connecting portion  631  has a shape that corresponds to the inlet  220  so that the connecting portion  631  can be fitted to the inlet  220 . Further, by pressing the operating member  615 , the catch between the pawl portion  635  and the recess formed in the inlet  220  is released, and as a result, the inlet  220  and the connecting portion  631  can be disconnected. In other words, a user can detach the power supply connector  600  from the vehicle  100  by pressing the operating member  615 . 
     The main body portion  634  includes a rod-shaped member that extends in an inclined direction oriented downward from a horizontal plane. Note that the main body portion  634  may include a rod-shaped member that extends in a vertical direction. One end of the main body portion  634  is connected to the main body portion  633 . The main body portion  633  and the main body portion  634  may be formed integrally or separately. 
     The socket  610  is provided on another end of the main body portion  634 . A projecting portion  641  that projects in an extension direction of the main body portion  634  is formed on an upper side of a surface on which the socket  610  is provided. By forming the projecting portion  641 , rainwater and the like can be prevented from adhering to the socket  610  when the power supply connector  600  is used outdoors in the rain. 
     The power supply connector  600  is provided with a cover  642  for protecting the surface provided with the socket  610  when the power supply connector  600  is not in use. As shown in  FIG. 3 , a rotary portion of the cover  642  is provided below the surface provided with the socket  610 . The cover  642  is formed to be capable of rotating in a rotation direction  684  using the rotary portion as a rotary center. When an outer edge part of the cover  642  is rotated until the cover  642  contacts the projecting portion  641 , the socket  610  is covered, and thus protected, by the cover  642 . 
     Further, when the cover  642  of the power supply connector  600  is open, the socket  610  is exposed. A terminal hole to which the plug  710  of the electric device  700  can be connected is formed in the socket  610 . The socket  610  has a similar shape to a socket disposed in a house or the like. 
       FIG. 4  is an overall block diagram of the vehicle  100  according to this embodiment. Referring to  FIG. 4 , the vehicle  100  includes a storage apparatus  110 , a system main relay (SMR)  115 , a power control unit (PCU)  120  serving as a driving apparatus, motor/generators  130 ,  135 , a power transmission gear  140 , a drive wheel  150 , an engine  160  constituted by an internal combustion engine, a power conversion apparatus  200 , a direct current (DC) current sensor  202 , an alternating current (AC) current sensor  204 , a charging relay (also referred to hereafter as a CHR)  210 , the inlet  220 , and an ECU  300  serving as a control apparatus. 
     The storage apparatus  110  is a chargeable/dischargeable power storage element. For example, the storage apparatus  110  is constituted by a secondary battery such as a lithium ion battery, a nickel hydrogen battery, or a lead storage battery, or a storage element such as an electric double layer capacitor. 
     The storage apparatus  110  is connected to the PCU  120  via a power line PL 1  and a ground line NL 1 . The storage apparatus  110  supplies power for generating a driving force of the vehicle  100  to the PCU  120 . Further, the storage apparatus  110  stores power generated by the motor/generators  130 ,  135 . An output of the storage apparatus  110  is approximately 200 V, for example. 
     The storage apparatus  110  includes a voltage sensor, a current sensor, and a temperature sensor, none of which are shown in the drawings, and a voltage VB, a current IB, and a battery temperature TB of the storage apparatus  110 , which are detected respectively by these sensors, are output to the ECU  300 . 
     One relay included in the SMR  115  is connected to a positive electrode terminal of the storage apparatus  110  and the power line PL 1  connected to the PCU  120 , while another relay is connected to a negative electrode terminal of the storage apparatus  110  and the ground line NL 1 . The SMR  115  switches between supplying and cutting off power between the storage apparatus  110  and the PCU  120  on the basis of a control signal SE 1  from the ECU  300 . 
     The PCU  120  includes a converter that performs voltage conversion between the storage apparatus  110  and an inverter, to be described below, on the basis of a control signal PWC from the ECU  300 , and the inverter that converts DC power supplied from the converter into AC power on the basis of control signals PWI 1 , PWI 2  from the ECU  300  and drives the respective motor/generators  130 ,  135 . 
     The motor/generators  130 ,  135  are AC rotating electric machines, for example permanent magnet synchronous motors including a rotor having an embedded permanent magnet. 
     An output torque of the motor/generators  130 ,  135  is transmitted to the drive wheel  150  via the power transmission gear  140 , which includes a reduction gear and a power distribution mechanism, to cause the vehicle  100  to travel. When a regenerative braking operation is underway in the vehicle  100 , the motor/generators  130 ,  135  are capable of generating power using a rotary force of the drive wheel  150 . This generated power is converted by the PCU  120  into charging power for the storage apparatus  110 . 
     Further, the motor/generators  130 ,  135  are joined to the engine  160  via the power transmission gear  140 . The motor/generators  130 ,  135  and the engine  160  are operated cooperatively by the ECU  300  so that a required vehicle driving force is generated. Furthermore, the motor/generators  130 ,  135  can generate power using a rotation of the engine  160 , and the storage apparatus  110  can be charged using the resulting generated power. 
     Note that in this embodiment, the motor/generator  135  is used exclusively as a motor for driving the drive wheel  150 , while the motor/generator  130  is used exclusively as a power generation apparatus driven by the engine  160 . 
     In the example shown in  FIG. 1 , two motor/generators are provided, but the number of motor/generators is not limited to two, and a single motor/generator or more than two motor/generators may be provided instead. 
     The vehicle  100  includes the power conversion apparatus  200 , the charging relay  210  (to be referred to hereafter as the CHR  210 ), and the inlet  220  serving as a connecting portion as a configuration for charging the storage apparatus  110  using power from an external power supply  500 , or supplying the power of the storage apparatus  110  or power generated by an MG 1  to an external load. 
     For example, when the power supply connector  600  is connected to the inlet  220 , a power supply operation is performed in the vehicle  100 . When a charging connector (not shown) connected to an external power supply (a commercial power supply, for example) on the outside of the vehicle  100  is connected to the inlet  220 , on the other hand, a charging operation is performed in the vehicle  100 . 
     The power conversion apparatus  200  is connected to the inlet  220  via power lines ACL 1 , ACL 2 . Further, the power conversion apparatus  200  is connected to the storage apparatus  110  by a power line PL 2  and a ground line NL 2  via the CHR  210 . 
     The power conversion apparatus  200  is controlled by a control signal PWD from the ECU  300  to convert AC power supplied from the inlet  220  into DC power for the storage apparatus  110 , and to convert the DC power of the storage apparatus  110  or DC power generated by the motor/generators  130 ,  135  and converted by the PCU  120  into AC power and supply the AC power to an electric device on the outside of the vehicle  100 . 
     The power conversion apparatus  200  may be a single apparatus capable of bidirectional power conversion for charging and supplying power, or may include individual apparatuses used respectively for charging and supplying power. 
     The CHR  210  is controlled by a control signal SE 2  from the ECU  300  to switch between supplying and cutting off power between the power conversion apparatus  200  and the storage apparatus  110 . 
     The DC current sensor  202  is provided on the ground line NL 2  to detect a DC Idc of the ground line NL 2 . The DC current sensor  202  transmits a signal indicating the detected DC Idc to the ECU  300 . 
     The AC current sensor  204  is provided on the ground line ACL 2  to detect an AC Iac of the ground line ACL 2 . The AC current sensor  204  transmits a signal indicating the detected AC Iac to the ECU  300 . 
     The ECU  300  includes a central processing unit (CPU)  310 , a resistor circuit  320 , an input buffer  340 , and a storage device (not shown). The ECU  300  receives signals input from the respective sensors and so on, outputs control signals to the respective devices, and controls the storage apparatus  110  and the respective devices of the vehicle  100 . Note that this control is not limited to software processing, and may be performed using dedicated hardware (electronic circuits). 
     The ECU  300  calculates a state of charge (SOC) of the storage apparatus  110  on the basis of detection values of the voltage VB, the current IB, and the battery temperature TB from the storage apparatus  110 . 
     The ECU  300  estimates a catalyst temperature on the basis of conditions (for example, an intake air amount, a rotation speed, a throttle opening, a fuel injection amount, an ignition timing, an intake air temperature, and so on) of the engine  160 . The ECU  300  may detect the catalyst temperature using a temperature sensor used in a catalyst, or the ECU  300  may estimate the catalyst temperature using a temperature sensor provided in the vicinity of the catalyst. 
     Note that in  FIG. 4 , a single control apparatus is provided as the ECU  300 , but instead, an individual control apparatus may be provided for each function or each controlled device so that, for example, a control apparatus is provided for the PCU  120 , a control apparatus is provided for the storage apparatus  110 , and so on. 
     When the power supply connector  600  is connected to the inlet  220 , the vehicle  100  side power lines ACL 1 , ACL 2  and the socket  610  are electrically connected via a power transmission unit  606 . 
     The power supply connector  600  further includes resistors R 30 , R 31  and a switch SW 30  constituting a connection detection circuit  611 . When the power supply connector  600  is connected to the inlet  220 , the resistors R 30 , R 31  are connected in series between a connection signal line L 3  and a ground line L 2 . 
     The switch SW 30  is connected in parallel with the resistor R 31 . When the power supply connector  600  is fitted securely into the inlet  220 , a contact of the switch SW 30  is closed. When the power supply connector  600  is disconnected from the inlet  220  and when the power supply connector  600  and the inlet  220  are not securely fitted, the contact of the switch SW 30  is open. The contact of the switch SW 30  is also opened by operating the operating member  615 . 
     When the power supply connector  600  is connected to the inlet  220 , the CPU  310  is capable of determining a connection condition and a fitting condition of the power supply connector  600  using a combined resistance defined by a combination of resistors R 10 , R 15 , R 30 , R 31 . 
     Note that a resistance value of the connection detection circuit in the power supply connector  600  is set at a different value to a resistance value of a connection detection circuit provided in the charging connector used in the charging operation. Accordingly, a potential of a connection signal PISW generated when the power supply connector  600  is fitted takes a different value to the potential of the connection signal PISW generated when the charging connector is fitted. As a result, the CPU  310  can determine which of the charging connector and the power supply connector  600  is connected to the inlet  220  on the basis of the potential of the connection signal PISW. 
     After acknowledging on the basis of the potential of the connection signal PISW that the power supply connector  600  is connected, the CPU  310  closes the CHR  210  and controls the power conversion apparatus  200  to perform the power supply operation, whereby the power of the storage apparatus  110  is supplied to the external electric device  700 . 
     The CPU  310  also drives the engine  160  to cause the motor/generator  130  to generate power, and supplies the generated power to the electric device  700 . 
     The resistance values of the connection detection circuits provided respectively in the power supply connector  600  and the charging connector used in the charging operation are set to be different from each other. As a result, the CPU  310  can determine which of the charging connector and the power supply connector  600  is connected to the inlet  220 . 
     The resistor circuit  320  is connected in series between a control pilot line L 1  over which a pilot signal CPLT used in the charging operation is communicated, and a vehicle earth  360 . The resistor circuit  320  is a circuit for manipulating a potential of the pilot signal CPLT from the vehicle  100  side. 
     A configuration in which the plug  710  of the external electric device  700  is connected to the power supply connector  600  was described above, but as shown in  FIG. 5 , a power supply cable  400 A capable of transmitting power from a power supply connector  410 A via a cable may also be used. 
     In the power supply cable  400 A shown in  FIG. 5 , a plug  420 A has a male type plug shape. By forming the plug  420 A of the power supply cable  400 A in this shape, power can be supplied to electric devices in a house  800  from the vehicle  100  when a power cut occurs in the house  800 , for example, by connecting the plug  420 A to an outlet  810  of the house  800 . In this case, the house  800  serves as the power supply subject. Moreover, power can be supplied to the individual electric device  700  using an adaptor  720  capable of connecting the plug  420 A of the power supply cable  400 A and the plug  710  of the electric device  700 . Note that the plug  420 A may also have a female type plug shape. 
     Alternatively, as shown in  FIG. 6 , a cable that is capable of switching between charging the storage apparatus  110  using an external power supply and supplying the power of the storage apparatus  110  or the power generated by the motor/generator  130  to the external electric device may be used. 
     A charging/power supply cable  400 B shown in  FIG. 6  is formed by replacing the power supply connector  410 A of the power supply cable  400 A illustrated in  FIG. 5  with a charging/power supply connector  410 B. 
     The charging/power supply connector  410 B is provided with a switch  416  in addition to the configuration of the power supply connector  410 A. The switch  416  is used to switch between the charging operation and the power supply operation, and by switching the switch  416  to “Emergency”, the vehicle  100  is caused to perform the power supply operation to the outside while driving the engine to generate power. Further, by switching the switch  416  to “Normal”, the vehicle  100  is caused to perform the charging operation. The switch between the charging operation and the power supply operation does not have to be performed manually, and may be performed by the vehicle  100  or by a power supply destination or a charging source (the house, for example). 
     In the vehicle configured as described above, the engine  160  may be driven in order to maintain the catalyst activation temperature even when an amount of power used by the electric device  700  serving as the power supply subject is small or the electric device  700  is temporarily stopped during an intermittent operation, and as a result, fuel may be consumed wastefully. 
     Hence, in this embodiment, when a power supply supplied to the electric device  700  serving as the power supply subject remains continuously smaller than a predetermined value during the power supply operation in which power is supplied to the electric device  700  from at least one of the motor/generator,  130  and the storage apparatus  110 , the ECU  300  suppresses an operation of the engine  160 . 
     More specifically, when the power supply remains smaller than the predetermined value continuously for more than a first time during the power supply operation, the ECU  300  stops the operation of the engine  160  or prohibits the engine  160  from operating. For example, in a case where the power supply remains smaller than the predetermined value continuously for more than the first time, the ECU  300  stops the operation of the engine  160  when the engine  160  is operative, and prohibits the engine  160  from operating when the engine  160  is stopped. 
     Further, when the power supply to the electric device  700  is equal to or larger than the predetermined value or when the duration of a condition in which the power supply is smaller than the predetermined value is equal to or shorter than the first time, the ECU  300  permits the engine  160  to operate. 
     For example, in a case where the power supply is equal to or larger than the predetermined value during the power supply operation or a case where the duration of a condition in which the power supply is smaller than the predetermined value is equal to or shorter than the first time during the power supply operation, the ECU  300  operates the engine  160  when the remaining capacity of the storage apparatus  110  falls below a threshold or the catalyst temperature of the engine  160  falls below a threshold. 
       FIG. 7  is a block diagram showing functions of the ECU  300  installed in the vehicle  100  according to this embodiment. The ECU  300  includes a mode determination unit  382 , a power supply determination unit  384 , an elapsed time determination unit  386 , a threshold setting unit  388 , an engine control unit  390 , a shutdown determination unit  392 , and a system shutdown processing unit  394 . 
     The mode determination unit  382  determines whether or not a power supply mode is set. For example, the mode determination unit  382  may determine that the power supply mode is set when the power supply connector  600  is connected to the inlet  220 . A method of determining whether or not the power supply connector  600  is connected to the inlet  220  was described above, and therefore detailed description thereof will not be repeated. 
     After determining that the power supply mode is set, the mode determination unit  382  may set a mode determination flag to ON, for example. 
     When the mode determination unit  382  determines that the power supply mode is set, the power supply determination unit  384  determines whether or not the power supply is stopped, or in other words whether or not the power supply is smaller than a predetermined value. 
     For example, the power supply determination unit  384  may determine that the power supply is stopped when a magnitude of a detection value of the DC Idc detected by the DC current sensor  202  is smaller than a threshold Idc (0). 
     Note that the threshold Idc (0) is a value for determining that the magnitude of the detection value of the DC Idc is substantially zero, which is set in consideration of detection errors and the like. 
     Alternatively, for example, the power supply determination unit  384  may determine that the power supply is stopped when a magnitude of an effective value of the AC Iac detected by the AC current sensor  204  is smaller than a threshold Iac (0). The power supply determination unit  384  calculates the magnitude of the effective value using a maximum value of a detection value of the AC Iac, for example. The threshold Iac (0) is a value for determining that the magnitude of the effective value of the AC Iac is substantially zero, which is set in consideration of detection errors and the like. 
     Alternatively, for example, the power supply determination unit  384  may determine that the power supply is stopped when a magnitude of the detection value of the current IB detected by the current sensor provided in the storage apparatus  110  is smaller than a threshold IB (0). The threshold IB (0) is set at a value at which the power supply to the electric device  700  can be determined to be smaller than the predetermined value, taking into consideration an amount of power consumed by accessories installed in the vehicle  100 , an amount of power consumed by switching loss, and so on. 
     Alternatively, for example, the power supply determination unit  384  may calculate a reduction in the SOC of the storage apparatus  110  per predetermined time, and determine that the power supply is stopped when a magnitude ΔSOC of the calculated reduction is smaller than a threshold ΔSOC (0). ΔSOC (0) is a value for determining that the reduction is substantially zero. 
     Alternatively, for example, the power supply determination unit  384  may determine that the power supply is stopped upon reception from the electric device  700  side (including the house) of information indicating that the electric device  700  is temporarily stopped during an intermittent operation or information indicating the power supply via the power supply connector, through wireless communication, or by another method. 
     The power supply determination unit  384  may determine that the power supply is stopped when the mode determination flag is ON, and after determining that the power supply is stopped, the power supply determination unit  384  may set a stoppage determination flag to ON. 
     Further, in a case where the power supply determination unit  384  determines whether or not the power supply is stopped by receiving information from the current sensor provided in the storage apparatus  110 , information indicating the SOC of the storage apparatus  110 , or information from the electric device  700  side, the DC current sensor  202  and the AC current sensor  204  may be omitted. 
     The elapsed time determination unit  386  determines whether or not a duration of a power supply stoppage has exceeded a predetermined first time. The first time is a threshold for determining whether or not the power supply remains stopped. 
     For example, the elapsed time determination unit  386  starts to measure the elapsed time (the duration of the power supply stoppage) using a timer or the like from the point at which the power supply is determined to be stopped. When the power supply operation is resumed during measurement of the elapsed time, the elapsed time determination unit  386  resets the elapsed time to an initial value, and when the power supply is subsequently determined to be stopped, the elapsed time determination unit  386  starts to measure the elapsed time again. 
     When the measured elapsed time exceeds the first time, the elapsed time determination unit  386  may set an elapse determination flag to ON, for example. 
     The threshold setting unit  388  sets an SOC threshold (to be referred to as a shutdown threshold hereafter) for executing system shutdown processing, to be described below, in accordance with whether or not the power supply remains stopped. 
     For example, the threshold setting unit  388  sets a threshold α as the shutdown threshold when the power supply is not stopped or the duration of the power supply stoppage has not exceeded the first time. 
     When the duration of the power supply stoppage has exceeded the first time, on the other hand, the threshold setting unit  388  sets a threshold β, for example, as the shutdown threshold. For example, the threshold setting unit  388  may set the threshold α as the shutdown threshold when the elapse determination flag is OFF and set the threshold β as the shutdown threshold when the elapse determination flag is ON. Note that the threshold α takes a smaller value than the threshold β. 
     The engine control unit  390  controls the engine  160  in accordance with whether or not the power supply remains stopped. More specifically, the engine control unit  390  permits the engine  160  to operate when the power supply is not stopped or when the duration of the power supply stoppage has not exceeded the first time. 
     For example, in a case where the power supply is not stopped or the duration of the power supply stoppage has not exceeded the first time, the engine control unit  390  operates the engine  160  when the SOC of the storage apparatus  110  falls below an electric vehicle (EV) threshold. 
     The EV threshold is a value for determining whether or not to operate the engine when the power supply is not stopped (i.e. when power supply is underway), and is a larger value than the threshold β. In other words, the EV threshold is a threshold of the SOC of the storage apparatus  110  for determining during the power supply operation whether to supply the power of the storage apparatus  110  to the power supply subject or to operate the engine  160  in order to supply power generated by the motor/generator  130  to the power supply subject in addition to or instead of the power of the storage apparatus  110 . 
     A value that enables the vehicle  100  to perform EV travel (travel using the motor/generator  135  while the engine  160  is stopped) for at least a predetermined distance following cancellation of the power supply mode, for example, is set as the EV threshold. 
     Note that the engine control unit  390  may operate the engine  160  in a case where the power supply is not stopped or the duration of the power supply stoppage has not exceeded the first time when the catalyst temperature of the engine  160  is smaller than a threshold, for example. The catalyst temperature threshold is set at a value at which the catalyst temperature can be determined to be within a catalyst activation temperature range. For example, the catalyst temperature threshold may be set at a lower limit value of the catalyst activation temperature range or a value that is higher than the lower limit value by a predetermined value. 
     Further, for example, the engine control unit  390  may permit the engine  160  to operate when the elapse determination flag is OFF. 
     When the duration of the power supply stoppage has exceeded the first time, on the other hand, the engine control unit  390  stops the operation of the engine  160  or prohibits the engine  160  from operating, for example. For example, the engine control unit  390  stops the operation of the engine  160  when the engine  160  is operative and prohibits the engine  160  from operating when the engine  160 , is stopped. 
     While the operation of the engine  160  is stopped or the engine  160  is prohibited from operating, the engine control unit  390  does not operate the engine  160  even when the catalyst temperature falls below the threshold, for example. 
     Further, for example, the engine control unit  390  may stop the operation of the engine  160  or prohibit the engine  160  from operating when the elapse determination flag is ON. 
     The shutdown determination unit  392  determines whether or not the SOC of the storage apparatus  110  has fallen to or below the shutdown threshold. When the power supply is not stopped or when the duration of the power supply stoppage does not exceed the first time, the shutdown determination unit  392  determines whether or not the SOC of the storage apparatus  110  has fallen to or below the threshold α. For example, the shutdown determination unit  392  may determine whether or not the SOC of the storage apparatus  110  has fallen to or below the threshold α when the elapse determination flag is OFF. 
     When the duration of the power supply stoppage exceeds the first time, for example, the shutdown determination unit  392  determines whether or not the SOC of the storage apparatus  110  has fallen to or below the threshold β. For example, the shutdown determination unit  392  may determine whether or not the SOC of the storage apparatus  110  has fallen to or below the threshold β when the elapse determination flag is ON. 
     After determining that the SOC of the storage apparatus  110  has fallen to or below the shutdown threshold, the shutdown determination unit  392  may set a shutdown determination flag to ON, for example. 
     Further, when the SOC of the storage apparatus  110  is larger than the shutdown threshold, for example, the shutdown determination unit  392  determines whether or not the duration of the power supply stoppage exceeds a predetermined second time. There are no particular limitations on the second time providing it is longer than the first time. 
     For example, the shutdown determination unit  392  may set the shutdown determination flag to ON when the duration of the power supply stoppage is determined to have exceeded the second time, even in a case where the SOC of the storage apparatus  110  is larger than the shutdown threshold. 
     The system shutdown processing unit  394  executes the system shutdown processing on the basis of a determination result obtained by the shutdown determination unit  392 . For example, the system shutdown processing unit  394  executes the system shutdown processing when the shutdown determination unit  392  determines that the SOC of the storage apparatus  110  has fallen to or below the shutdown threshold or when the duration of the power supply stoppage is determined to have exceeded the second time. 
     The system shutdown processing unit  394  executes processing for stopping a system of the vehicle  100  that is activated during the power supply operation as the system shutdown processing. For example, the system shutdown processing unit  394  sets the CHR  210  in a shutdown condition. Note that as long as the system shutdown processing unit  394  can stop the system of the vehicle  100  that is activated during the power supply operation, the system shutdown processing unit  394  is not limited to setting the CHR  210  in the shutdown condition. For example, the system shutdown processing unit  394  may control the power conversion apparatus  200  to stop the power supply operation. 
     Further, the system shutdown processing unit  394  may execute the system shutdown processing when, for example, the shutdown determination flag is ON. 
     In this embodiment, the mode determination unit  382 , the power supply determination unit  384 , the elapsed time determination unit  386 , the threshold setting unit  388 , the engine control unit  390 , the shutdown determination unit  392 , and the system shutdown processing unit  394  all function as software that is realized by having the CPU  310  of the ECU  300  execute a program stored in the storage device. However, these units may be realized by hardware. Note that the program is recorded on a storage medium and installed in the vehicle. 
     Referring to  FIG. 8 , a control structure of the program executed by the ECU  300  installed in the vehicle  100  according to this embodiment will now be described. 
     In Step (to be abbreviated to S hereafter)  100 , the ECU  300  determines whether or not the power supply mode is set. When it is determined that the power supply mode is set (YES in S 100 ), the processing advances to S 102 . Otherwise (NO in S 100 ), the processing returns to S 100 . 
     In S 102 , the ECU  300  determines whether or not the power supply is stopped. When it is determined that the power supply is stopped (YES in S 102 ), the processing advances to S 104 . Otherwise (NO in S 102 ), the processing advances to S 110 . 
     Note that a method of determining whether or not the power supply mode is set and a method of determining whether or not the power supply is stopped were described above, and therefore detailed description thereof will not be repeated. 
     In S 104 , the ECU  300  determines whether or not the duration of the power supply stoppage exceeds the first time. When it is determined that the duration of the power supply stoppage exceeds the first time (YES in S 104 ), the processing advances to S 106 . Otherwise (NO in S 104 ), the processing advances to S 110 . 
     In S 106 , the ECU  300  sets the threshold β as the shutdown threshold. In S 108 , the ECU  300  stops the operation of the engine  160  or prohibits the engine  160  from operating. In S 110 , the ECU  300  sets the threshold α as the shutdown threshold. 
     In S 112 , the ECU  300  determines whether or not the SOC of the storage apparatus  110  is smaller than the EV threshold. When it is determined that the SOC of the storage apparatus  110  is smaller than the EV threshold (YES in S 112 ), the processing advances to S 114 . Otherwise (NO in S 112 ), the processing advances to S 116 . 
     In S 114 , the ECU  300  operates the engine  160 . When the engine  160  is operative, the ECU  300  maintains the operation. 
     In S 116 , the ECU  300  determines whether or not the SOC of the storage apparatus  110  has fallen to or below the shutdown threshold. When it is determined that the SOC of the storage apparatus  110  has fallen to or below the shutdown threshold (YES in S 116 ), the processing advances to S 120 . Otherwise (NO in S 116 ), the processing advances to S 118 . 
     In S 118 , the ECU  300  determines whether or not the duration of the power supply stoppage exceeds the second time. When it is determined that the duration of the power supply stoppage exceeds the second time (YES in S 118 ), the processing advances to S 120 . Otherwise (NO in S 118 ), the processing returns to S 100 . 
     In S 120 , the ECU  300  executes the system shutdown processing. The system shutdown processing was described above, and therefore detailed description thereof will not be repeated. 
     An operation of the ECU  300  installed in the vehicle according to this embodiment, based on the above structure and flowchart, will now be described. 
     For example, when the power supply connector  600  is attached to the inlet  220  of the vehicle  100  and the plug  710  of the electric device  700  is connected to the power supply connector  600 , the power supply operation is performed in the vehicle  100  (YES in S 100 ). 
     More specifically, the CHR  210  is switched ON (to a conductive condition) such that the DC power of the storage apparatus  110  is converted into AC power by the power conversion apparatus  200 , and the converted AC power is supplied to the electric device  700  via the inlet  220 , the power supply connector  600 , and the plug  710 . 
     When the electric device  700  is temporarily stopped during an intermittent operation or the like such that the power supply is stopped (YES in S 102 ) and the duration of the power supply stoppage exceeds the first time (YES in S 104 ), the threshold β is set as the shutdown threshold (S 106 ) and the operation of the engine  160  is stopped or the engine  160  is prohibited from operating (S 108 ). 
     Hence, when the engine  160  is operative, the engine  160  is stopped, and when the engine  160  is stopped, the engine  160  is prohibited from operating. The operation of the engine  160  is likewise suppressed when, for example, the catalyst temperature falls below the activation temperature while the engine  160  is stopped. 
     When the SOC of the storage apparatus  110  falls to or below the shutdown threshold (here, the threshold β) due to power consumption by the electric device  700  (YES in S 116 ), the system shutdown processing is executed (S 120 ), whereby the CHR  210  is switched OFF (to a shutdown condition). 
     In a case where the duration of the power supply stoppage exceeds the second time (S 118 ), the system shutdown processing is executed (S 120 ) even when the SOC of the storage apparatus  110  is larger than the shutdown threshold (NO in S 116 ). 
     When the power supply is not stopped (NO in S 102 ) or the power supply is stopped (YES in S 102 ) but the duration of the power supply stoppage does not exceed the first time (NO in S 104 ), on the other hand, the threshold α is set as the shutdown threshold (S 110 ). 
     In this case, the engine  160  is operated (S 114 ) when the SOC of the storage apparatus  110  is smaller than the EV threshold (YES in S 112 ). 
     When the SOC of the storage apparatus  110  falls to or below the shutdown threshold (here, the threshold α) (YES in S 116 ), the system shutdown processing is executed (S 120 ), whereby the CHR  210  is switched OFF (to the shutdown condition). 
     In a case where the duration of the power supply stoppage exceeds the second time (S 118 ), the system shutdown processing is executed (S 120 ) even when the SOC of the storage apparatus  110  is larger than the shutdown threshold (NO in S 116 ). 
     With the vehicle according to this embodiment, as described above, when the power supply remains smaller than the predetermined value continuously for more than the first time during the power supply operation for supplying power from the vehicle  100  to the power supply subject, the operation of the engine  160  is stopped or the engine  160  is prohibited from operating. Accordingly, the engine  160  is not operated even when an operation of the engine  160  is requested due to a reduction in the catalyst temperature or the like in a case where the electric device  700  is temporarily stopped during an intermittent power supply operation or the like. As a result, wasteful fuel consumption can be avoided. Furthermore, a wasteful operation of the engine  160  can be avoided, and therefore an increase in exhaust gas emissions into the air around the vehicle can be suppressed. It is therefore possible to provide a vehicle and a control method for the vehicle with which the engine is controlled appropriately in accordance with the operating conditions of the power supply destination. 
     Moreover, when the power supply is stopped, power is consumed only by the accessories of the vehicle  100  and by switching loss and the like occurring in the power generation apparatus, and therefore the power consumption is suppressed. Stand-by is therefore possible for a long time until an operation of the electric device  700  is resumed using the storage apparatus  110  alone without stopping the system of the vehicle  100  that is operated during the power supply operation. 
     Further, when the duration of the power supply stoppage exceeds the second time, the system of the vehicle  100  that is activated during the power supply operation is stopped, whereby a reduction in the SOC can be suppressed. As a result, a situation in which the power supply mode is selected and then left so that the vehicle  100  cannot perform EV travel subsequently due to a reduction in the SOC can be avoided. 
     The embodiments disclosed herein are entirely exemplary, and are not intended to be limiting. The scope of the invention is defined by the claims rather than the above description, and includes all modifications equivalent in meaning to the claims and within the scope thereof.