Hybrid vehicle and method for controlling the hybrid vehicle

Abstract

Hybrid vehicle, exhibiting: an electric generator (100) which is configured to generate electrical power to drive the hybrid vehicle; a drive motor (170) which is configured to operate in a power driving mode in which the drive motor (170) drives the hybrid vehicle, or in a braking time power generation mode in which the drive motor (170) generates electrical braking time power by operating as a generator and generates a braking force for the hybrid vehicle; a power storage device (650) configured to store the electrical power generated by the electric generator (100) and the electrical braking time interval power generated by the drive motor (170); a power-consuming device (130; 525; 535; 127) configured to consume electrical power; and a controller (200) which is configured to control the control of the power consumption device (130; 525; 535; 127), wherein the controller (200) is configured to perform a power consumption increase control when a vehicle power balance value (Wa) is greater than a first threshold (Th1) while the drive motor (170) is operating in the braking time span power generation mode, the vehicle power balance value (Wa) corresponds to a vehicle power balance value that does not include any charging and discharging amount of the power storage device (650) and is obtained by subtracting a vehicle consumption power consumed by the hybrid vehicle from a vehicle generation power, the vehicle generation power corresponds to an electrical power generated by the hybrid vehicle, including an estimated value of the electrical braking time span power, the power consumption increase control of a control for setting a power consumption of the power consumption device (130; 525; 535; 127) to a greater value than the power consumption of the power consumption device (130; 525; 535; 127) at the vehicle power balance value (Wa), which is less than a second threshold (Th2) that is set less than the first threshold (Th1), corresponds to the first threshold (Th1) is preset on the basis of a permissible dischargeable power (Wout), which is determined as an upper limit of the electrical power to be discharged by the power storage device (650) depending on a state of the power storage device (650), the first threshold (Th1) at the permissible dischargeable power (Wout), which is less than a predetermined first reference power value (W1), is set higher than the first threshold (Th1) at the permissible dischargeable power (Wout), which is equal to or greater than the first reference power value (W1), the second threshold (Th2) at the permissible discharge power (Wout), which is less than the first reference power value (W1), is set higher than the second threshold (Th2) at the permissible discharge power (Wout), which is equal to or greater than the first reference power value (W1), and the controller (200) is configured to terminate the power consumption increase control when the vehicle power balance value (Wa) is less than the second threshold (Th2) after a start of the power consumption increase control.

Description

Background of the invention 1. Field of the invention

[0001] The present invention relates to a hybrid vehicle and a method for controlling the hybrid vehicle. 2. Description of the relevant state of the art

[0002] In a fuel cell vehicle with a fuel cell, if the electrical power generated by a drive motor during braking exceeds the chargeable power of a power storage device, excess electrical power can be generated that cannot be stored in the power storage device. A configuration is known in which power-consuming means consume the excess electrical power (see, for example, JP 2013 – 99 081 A).

[0003] Furthermore, DE 10 2013 009 732 A1 discloses a method and a system for distributing recuperation power for a vehicle, wherein the following steps are carried out for distribution: determining the recuperation power, recording a respective target power of at least one energy consumer, distributing the recuperation power to electrical energy sinks, which include an energy storage device and the at least one energy consumer, depending on the respective target power of the at least one energy consumer, such that an average actual power of the at least one energy consumer corresponds to the respective target power of the at least one energy consumer. Summary of the invention

[0004] The required power output of the vehicle can vary, for example, depending on changes in driving conditions. The state of the power storage device can also vary. These fluctuations in required power and the state of the power storage device can affect the electrical power balance of the fuel cell vehicle. Therefore, a technology is needed to balance the generation and consumption of electrical power in the fuel cell vehicle, even when the required power or the state of the power storage device varies during operation, in order to ensure that the power consumption device uses the excess electrical power.Such a challenge is not limited to the fuel cell vehicle, but can also occur in hybrid vehicles, each comprising an energy generator configured to produce energy to propel the vehicle, a power storage device and a drive motor, each configured to obtain braking force by causing the drive motor to generate electrical power while the vehicle is braking.

[0005] The present invention can be implemented in the following form.

[0006] A hybrid vehicle according to a first aspect of the present invention comprises an electric generator, a drive motor, a power storage device, a power consumption device, and a controller. The electric generator is configured to produce electrical power for driving the hybrid vehicle. The drive motor is configured to operate in one of two modes: a power driving mode, in which the drive motor drives the hybrid vehicle, and a braking power generation mode, in which the drive motor generates braking power by operating as a generator and provides braking force for the hybrid vehicle. The power storage device is configured to store the electrical power produced by the electric generator and the braking power produced by the drive motor.The power consumption device is configured to consume electrical power. The controller is configured to control the operation of the power consumption device. The controller is configured to execute a power consumption increase control when a vehicle power balance value is greater than a first threshold while the drive motor is operating in the braking time power generation mode. The vehicle power balance value is a vehicle power balance value that excludes the charging and discharging of the power storage device and is obtained by subtracting the vehicle consumption power consumed by the hybrid vehicle from the vehicle generation power. The vehicle generation power is the electrical power generated by the hybrid vehicle, including an estimated value of the electric braking time power.The power consumption increase control corresponds to a control for setting the power consumption of the power consumption device to a higher value than the power consumption of the power consumption device at the vehicle power balance value, which is lower than a second threshold that is set lower than the first threshold. The first threshold is preset based on a permissible discharge power, which is determined as an upper limit of the electrical power to be discharged by the power storage device depending on its state. The first threshold for permissible discharge power that is lower than a predetermined first reference power value is set higher than the first threshold for permissible discharge power that is equal to or greater than the first reference power value.The second threshold for permissible dischargeable power, which is lower than the first reference power value, is set higher than the second threshold for permissible dischargeable power, which is equal to or greater than the first reference power value. The controller is configured to terminate the power consumption increase control if the vehicle power balance value is lower than the second threshold after the power consumption increase control has been initiated.

[0007] In the hybrid vehicle according to the first aspect of the present invention, when implementing the power consumption increase control to increase the power consumption of the power consumption device during braking, the second threshold, which corresponds to the reference value of the vehicle power balance for terminating the power consumption increase control, is set lower than the first threshold, which corresponds to the reference value of the vehicle power balance for initiating the power consumption increase control. The first threshold and the second threshold for permissible dischargeable power that is lower than the first reference power value are higher than the first threshold and the second threshold, respectively, for permissible dischargeable power that is equal to or greater than the first reference power value.Therefore, the generation and consumption of electrical power in the hybrid vehicle can continue to be balanced even if the required power of the vehicle or the state of the power storage device varies when the power consumption increase control is executed.

[0008] In the hybrid vehicle according to the first aspect of the present invention, the first threshold for permissible dischargeable power, which is less than the first reference power value and greater than a second reference power value that is less than the first reference power value, can be set such that it increases as the permissible dischargeable power decreases. The second threshold for permissible dischargeable power, which is less than the first reference power value and greater than the second reference power value, can be set such that it increases as the permissible dischargeable power decreases.

[0009] In the hybrid vehicle according to the first aspect of the present invention, a deficiency or shortfall of electrical power in the hybrid vehicle can be suppressed due to the implementation of the power consumption increase control before the power consumption increase control is terminated, in the event of decreasing permissible dischargeable power.

[0010] In the hybrid vehicle according to the first aspect of the present invention, the controller can be configured such that, after a predetermined first reference time has elapsed without the start of the power consumption increase control, the first threshold is set to zero after the power consumption increase control has ended, until the power consumption increase control is subsequently started.

[0011] In the hybrid vehicle according to the first aspect of the present invention, even in a case where the vehicle power balance value can remain positive, provided the first threshold is not set to zero, an excessive increase in electrical power can be suppressed by starting the power consumption increase control for the power consumption device.

[0012] In the hybrid vehicle according to the first aspect of the present invention, the controller can be configured such that if a predetermined second reference time or longer elapses while the vehicle power balance value remains equal to or greater than the second threshold and equal to or less than the first threshold without the power consumption increase control being executed, the first threshold is set to zero until the power consumption increase control is subsequently started.

[0013] In the hybrid vehicle according to the first aspect of the present invention, even in a case where the vehicle power balance value can remain positive, provided the first threshold is not set to zero, an excessive increase in electrical power can be suppressed by starting the power consumption increase control for the power consumption device.

[0014] In the hybrid vehicle according to the first aspect of the present invention, the controller can be configured such that if a predetermined third reference time elapses without termination of the power consumption increase control after a start of the power consumption increase control, the second threshold is set to zero until the power consumption increase control is subsequently terminated.

[0015] In the hybrid vehicle according to the first aspect of the present invention, even in a case where the vehicle power balance value may remain negative, provided the second threshold is not set to zero, a shortfall in electrical power due to the power consumption of the power consumption device can be suppressed by terminating the power consumption increase control for the power consumption device.

[0016] In the hybrid vehicle according to the first aspect of the present invention, the controller can be configured such that if a predetermined fourth reference time or longer elapses while the vehicle power balance value remains equal to or greater than the second threshold and equal to or less than the first threshold during the execution of the power consumption increase control, the second threshold is set to zero until the power consumption increase control is subsequently terminated.

[0017] In the hybrid vehicle according to the first aspect of the present invention, even in a case where the vehicle power balance value may remain negative, provided the second threshold is not set to zero, a shortfall in electrical power due to the power consumption of the power consumption device can be suppressed by terminating the power consumption increase control for the power consumption device.

[0018] In a method for controlling a hybrid vehicle according to the second aspect of the present invention, the hybrid vehicle comprises an electric generator configured to generate electrical power for driving the hybrid vehicle, a drive motor configured to operate in any mode consisting of a power driving mode in which the drive motor drives the hybrid vehicle and a braking power generation mode in which the drive motor generates braking power by operating as a generator and produces a braking force for the hybrid vehicle, a power storage device configured to store the electrical power generated by the electric generator and the braking power generated by the drive motor, and a power consumption device configured tothat this electrical power is consumed. The procedure for controlling the hybrid vehicle includes executing a power consumption increase control when a vehicle power balance value is greater than a first threshold while the drive motor is operating in the braking time span power generation mode, and terminating the power consumption increase control when the vehicle power balance value is less than the second threshold after a power consumption increase control initiation. The vehicle power balance value corresponds to a vehicle power balance value,which does not include the charging and discharging amount of the energy storage device and which is obtained by subtracting the vehicle consumption power consumed by the hybrid vehicle from the vehicle generation power. The vehicle generation power corresponds to the electrical power generated by the hybrid vehicle, including an estimated value of the electric braking time interval power. The energy consumption increase control corresponds to a control for setting the energy consumption of the energy storage device to a higher value than the energy consumption of the energy storage device at the vehicle energy balance value, which is lower than a second threshold set lower than the first threshold. The first threshold is preset based on a permissible dischargeable power.which is determined as an upper limit of the electrical power to be discharged by the power storage device, depending on the state of the device. The first threshold for permissible dischargeable power, which is less than a predetermined first reference power value, is set higher than the first threshold for permissible dischargeable power that is equal to or greater than the first reference power value. The second threshold for permissible dischargeable power, which is less than the first reference power value, is set higher than the second threshold for permissible dischargeable power that is equal to or greater than the first reference power value. Brief description of the illustrations

[0019] Features, advantages and the technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying figures, in which the same reference numerals denote the same elements, and wherein Fig. 1 is an explanatory illustration which schematically depicts the overall configuration of a fuel cell vehicle; Fig. 2 is a flowchart that represents a power consumption control processing routine; Fig. 3. An explanatory figure shows the conditions for starting and stopping the power consumption increase control for a power consumption device; Fig. 4 is an explanatory figure that shows the conditions for starting and stopping the power consumption increase control in a comparative example; Fig. 5 is a flowchart which represents a threshold change control processing routine; Fig. 6 is a flowchart that represents a threshold change control processing routine; Fig. 7 is a flowchart that represents a threshold change control processing routine; and Fig. Figure 8 is a flowchart that represents a threshold change control processing routine. Detailed description of embodiments A. First embodiment (A-1) Overall configuration of the fuel cell vehicle

[0020] Fig. Figure 1 is an illustrative figure that schematically depicts the overall configuration of a fuel cell vehicle 20 according to a first embodiment of the present invention. The fuel cell vehicle 20 comprises a fuel cell system 30, a power circuit 600, a drive motor 170, and a controller 200. The fuel cell system 30 is mounted on the fuel cell vehicle 20 as a drive power supply and comprises a fuel cell (an electric generator) 100, a fuel gas supply system 120, an oxidation gas supply system 140, an exhaust system 400, and a cooling system 500.

[0021] The fuel cell 100 has a stacked structure with a plurality of stacked individual cells. This embodiment of the fuel cell 100 corresponds to a polymer electrolyte fuel cell, but a solid oxide fuel cell or other types of fuel cells can be used instead. In each individual cell of the fuel cell 100, a channel through which fuel gas flows (anode channel) is formed on an anode side, corresponding to one side of a proton exchange membrane, and a channel through which oxidation gas flows (cathode channel) is formed on a cathode side, corresponding to the other side of the proton exchange membrane. Furthermore, a coolant channel is formed inside the fuel cell 100. A coolant flows through the coolant channel to cool the fuel cell 100.

[0022] The fuel gas supply system 120 comprises a fuel gas tank 110, a hydrogen supply channel 121, a fuel gas discharge channel 128, a circulation channel 122, a main shut-off valve 124, a regulator 125, an injector 126, a gas-liquid separator 129, and a circulation pump 127. The fuel gas tank 110 is a storage device that stores hydrogen gas as fuel and is connected to the fuel cell 100 via the hydrogen supply channel 121. In the fuel gas supply system 120, the main shut-off valve 124 opens or closes the hydrogen supply channel 121, the regulator 125 reduces the pressure, and the injector 126 expels the hydrogen gas, so that the hydrogen gas stored in the fuel gas tank 110 is supplied to the anode channel of the fuel cell 100.

[0023] An anode exhaust gas emitted by the fuel cell 100 flows through the fuel gas discharge channel 128. The circulation channel 122 is connected to the fuel gas discharge channel 128 and to a portion of the hydrogen supply channel 121 on the downstream side of the injector 126. The circulation pump 127 adjusts the pressure of the hydrogen circulating through the circulation channel 122. The amount of fuel gas supplied to the fuel cell 100 can be adjusted depending on the control parameters of the injector 126 and the circulation pump 127. The injector 126 and the circulation pump 127 are controlled by the controller 200.

[0024] The gas-liquid separator 129 is provided at a connecting section between the fuel gas discharge channel 128 and the circulation channel 122. The gas-liquid separator 129 separates water and gas (including hydrogen and nitrogen) in the anode exhaust gas. In this embodiment, impurities, including nitrogen and water vapor, are removed from a channel, including the circulation channel 122, via the gas-liquid separator 129 and a purge valve 440, which is provided at a fuel gas discharge channel 430 described later.

[0025] The oxidation gas supply system 140 comprises a compressor 130, an oxidation gas supply channel 141, and a flow divider valve 144. The fuel cell 100 of this embodiment uses air as the oxidation gas. The compressor 130 is driven by an air compressor motor 135 to compress air and supplies the air via the oxidation gas supply channel 141 to the cathode channel of the fuel cell 100. The flow divider valve 144 is provided on the oxidation gas supply channel 141 at a connecting section between the oxidation gas supply channel 141 and an oxidation gas bypass channel 450, which is described later and is connected to the oxidation gas supply channel 141.

[0026] The exhaust system 400 comprises an exhaust duct 410, a pressure regulating valve 420, the fuel gas discharge duct 430, the purge valve 440, and the oxidation gas bypass duct 450. Cathode exhaust gas is discharged from the fuel cell 100 via the exhaust duct 410. The pressure regulating valve 420 is located on the exhaust duct 410 and adjusts the pressure of the oxidation gas in the fuel cell 100. The fuel gas discharge duct 430 connects the gas-liquid separator 129 and the exhaust duct 410. The purge valve 440 is located on the fuel gas discharge duct 430. If the nitrogen concentration in the anode exhaust gas increases, or if the amount of water in the gas-liquid separator 129 increases, the controller 200 opens the purge valve 440 to discharge water and gas from the gas-liquid separator 129. Therefore, the concentration of impurities in the fuel gas circulating through the channel as described above is reduced.The fuel gas discharge channel 430 is connected to a portion of the exhaust gas channel 410 on the downstream side of the pressure regulating valve 420. Hydrogen in the anode exhaust gas, which is to be discharged via the purge valve 440, is diluted by the cathode exhaust gas before being released into the atmosphere.

[0027] The oxidation gas bypass channel 450 connects the oxidation gas supply channel 141 and the exhaust gas channel 410. The flow divider valve 144 is provided at the connection section between the oxidation gas bypass channel 450 and the oxidation gas supply channel 141.

[0028] The cooling system 500 comprises a coolant supply channel 510, a coolant discharge channel 515, a coolant pump 525, and a radiator 530. Coolant is supplied to the fuel cell 100 via the coolant supply channel 510. The coolant pump 525 is located on the coolant supply channel 510 to adjust the flow rate of the coolant flowing through the channel. The coolant is discharged from the fuel cell 100 via the coolant discharge channel 515. The radiator 530 for cooling the coolant is located between a downstream portion of the coolant discharge channel 515 and an upstream portion of the coolant supply channel 510. The radiator 530 is equipped with a cooling fan 535. The radiator 530 cools the coolant using air supplied by the cooling fan 535 and air drawn into the fuel cell vehicle 20 during operation.

[0029] The power circuit 600 comprises the fuel cell 100, which is also part of the fuel cell system 30, a fuel cell (FC) boost converter 605 (FDC 605), an inverter 610, a battery converter 630, and a power storage device 650. In addition to the drive motor 170, various fuel cell auxiliary devices and various vehicle auxiliary devices are connected to the power circuit 600. The power circuit 600 is equipped with a current sensor and a voltage sensor configured to detect the output current and voltage of the fuel cell 100, respectively, thereby enabling the power output of the fuel cell 100 to be measured.

[0030] The fuel cell boost converter 605 is a direct current-to-direct current (DC / DC) converter configured to increase the output voltage of the fuel cell 100 to a high voltage usable by the drive motor 170. The inverter 610 converts the DC voltage increased by the fuel cell boost converter 605 into an alternating current (AC) voltage and supplies the AC voltage to the drive motor 170. The drive motor 170 powers the vehicle's wheels and can operate in both a power driving mode and a braking power generation mode. In the power driving mode, the drive motor 170 performs a power driving operation to propel the fuel cell vehicle 20. In the braking time power generation mode, the drive motor 170 generates an electrical braking time power described later by operating as a generator, and also generates a braking force for the fuel cell vehicle 20.

[0031] The battery converter 630 is a bidirectional DC / DC converter configured to either reduce a voltage increased by the fuel cell boost converter 605 or a voltage generated by the drive motor 170 during vehicle braking and supply the voltage to the power storage device 650, or increase a voltage from the power storage device 650 and supply the voltage to the inverter 610. The power storage device 650 can store electrical power generated by the fuel cell 100 and the electrical braking power generated by the drive motor 170 during vehicle braking. It serves as a power supply configured to deliver this electrical power to loads, including the drive motor 170 and various auxiliary devices. In this embodiment, the power storage device 650 is a rechargeable secondary battery.Examples of the secondary battery include a lithium-ion battery and a nickel-metal hydride battery. The power storage device 650 can be any rechargeable device other than the secondary battery, characterized by a capacitor. The power storage device 650 is equipped with a battery sensor 655, which is configured to detect operating states, such as voltage, current, and state of charge (SOC), of the power storage device 650.

[0032] The controller 200 is a microcomputer with a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and input / output ports. The controller 200 controls the power generation of the fuel cell system 30 and also controls the entire fuel cell vehicle 20, including the power circuit 600. The controller 200 receives output signals from sensors located in various parts of the fuel cell vehicle 20 (for example, an accelerator pedal actuation sensor, a shift position sensor, an outside temperature sensor, and a vehicle speed sensor). The controller 200 outputs control signals to various components related to the power generation and operation of the fuel cell vehicle 20.The controller 200, which performs the functions described above, need not be a single controller. For example, the controller 200 can be composed of multiple controllers, and the controllers can exchange necessary information. Examples of the controllers include one controller related to the operation of the fuel cell system 30, one controller related to the driving of the fuel cell vehicle 20, and one controller configured to control vehicle auxiliary devices unrelated to driving. (A-2) Operation during braking

[0033] The fuel cell vehicle 20 of this embodiment has a feature relating to a control system that is to be executed during braking. The following section first describes an overview of the operation of the fuel cell vehicle 20 during braking.

[0034] When the fuel cell vehicle 20 is braked, particularly when the accelerator pedal input is zero while the vehicle is in motion, the drive motor 170 operates in the braking time-span power generation mode, as described above. The drive motor 170 brakes the fuel cell vehicle 20 by converting the kinetic energy of the fuel cell vehicle 20 into electrical power. The electrical power generated by the drive motor 170 during braking is also referred to as "electric braking time-span power".

[0035] When the vehicle is braking, that is, when the accelerator pedal input is zero while the vehicle is in motion, the required power output of fuel cell 100 is zero. If power generation in fuel cell 100 stops while air remains in the fuel cell 100, the cathode potential rises extremely, and degradation of the electrode catalyst can progress. In this embodiment, an excessive rise in the cathode potential during vehicle braking is suppressed by setting an upper limit on the output voltage of fuel cell 100 to a high-potential avoidance voltage V. FCA voltage is set in advance as a permissible voltage, and an infinitesimal current is swept from fuel cell 100. At this time, the air supply to fuel cell 100 can be stopped, or air can be supplied to fuel cell 100 in a reduced quantity compared to the amount during normal power generation. The power generation in fuel cell 100 for sweeping the infinitesimal current during the setting of the high-potential avoidance voltage V FC The upper limit voltage during braking of the vehicle is also referred to as "infinitesimal power generation".

[0036] As described above, during braking of the fuel cell vehicle 20, the drive motor 170 can generate the electrical braking time span power, and the fuel cell 100 can generate the infinitesimal power with the high potential avoidance voltage V set as the upper limit voltage. FC perform. In this embodiment, a “vehicle power balance value” indicating an electrical power balance in the fuel cell vehicle 20 can be defined as a “value that does not include the charge / discharge amount of the power storage device 650 and is obtained by subtracting the electrical power consumed by the fuel cell vehicle 20 from the vehicle generation power, which corresponds to the electrical power generated by the fuel cell vehicle 20, including an estimate of the electrical braking time span power”.

[0037] A vehicle power balance value Wa during braking of the fuel cell vehicle 20 can be represented by expression (1). In expression (1), Wr represents a value derived as the electrical braking power to be generated by the drive motor 170 when the accelerator pedal is OFF. The electrical braking power Wr is not actually generated at present, but corresponds to an estimated value of the electrical power to be generated by the drive motor 170 and is derived before the calculation of the vehicle power balance value Wa, for example by using a vehicle speed when the accelerator pedal is OFF.The electrical braking time power Wr can be determined, for example, by pre-storing a characteristic map showing relationships between parameters, including vehicle speed, and the electrical braking time power to be generated, and by referencing the characteristic map when the parameters, including vehicle speed, are obtained. In expression (1), Ws represents electrical power generated by the infinitesimal power generation in the fuel cell 100. In expression (1), We represents an auxiliary device power consumption, which corresponds to electrical power consumed by the auxiliary devices mounted on the fuel cell vehicle 20.After the fuel cell vehicle 20 initiates the power consumption increase control for a power consumption device described later, the auxiliary device power consumption We in expression (1) includes an increased power consumption of the power consumption device. The sum of the electrical braking time power Wr and the electrical power Ws generated by the infinitesimal power generation is also referred to as the "vehicle generation power." The auxiliary device power consumption We is also referred to as the "vehicle consumption power" during braking. Any auxiliary device whose power consumption is negligible can be neglected when calculating the auxiliary device power consumption We in expression (1). Wa=Wr+Ws−We

[0038] If the vehicle power balance value Wa is positive, the power storage device 650 is charged with the vehicle power balance value Wa, that is, excess electrical power that is not consumed by the auxiliary equipment in relation to the electrical power generated by the fuel cell vehicle 20. A permissible chargeable power Win is set in the power storage device 650. If the vehicle power balance value Wa is equal to or less than the permissible chargeable power Win, the power storage device 650 can be charged with the excess electrical power without any problems. The permissible chargeable power Win corresponds to a value that is determined as an upper limit of the chargeable power of the power storage device 650, depending on the state of the power storage device 650, and indicates a charging capacity of the power storage device 650.As the permissible rechargeable power increases, the charging capacity also increases, meaning that the 650 power storage device can be charged with more electrical power.

[0039] If the vehicle power balance value Wa is negative, the vehicle power balance value Wa, that is, electrical power consumed by the auxiliary equipment of the fuel cell vehicle 20, but insufficient for the electrical braking time interval power Wr and the electrical power Ws generated by the infinitesimal power generation, is covered by electrical power output from the power storage device 650. A permissible dischargeable power Wout is set in the power storage device 650. If the absolute value of the vehicle power balance value Wa is equal to or less than the permissible dischargeable power Wout, electrical power corresponding to the shortfall can easily be supplied by the power storage device 650.The permissible dischargeable power Wout corresponds to a value that is determined as an upper limit of the output power of the power storage device 650, depending on the state of the device, and indicates a discharge capability of the power storage device 650. As the permissible dischargeable power Wout increases, the discharge capability also increases, meaning that the power storage device 650 can deliver more electrical power.

[0040] Both the permissible chargeable power Win and the permissible dischargeable power Wout correspond to a value determined by the state of charge (SOC) and the temperature of the power storage device 650. In this embodiment, relationships between the permissible chargeable power Win and the state of charge and temperature of the power storage device 650, and relationships between the permissible dischargeable power Wout and the state of charge and temperature of the power storage device 650, are predetermined for each fuel cell 100, and characteristic maps showing these relationships are pre-stored in the memory of the controller 200.The controller 200 obtains the permissible chargeable power Win and the permissible dischargeable power Wout by obtaining the state of charge of the power storage device 650 from the battery sensor 655, the temperature of the power storage device 650 from a temperature sensor (not shown), and by referring to the characteristic maps. (A-3) Power consumption increase control for power consumption device

[0041] Fig. Figure 2 is a flowchart representing a power consumption control processing routine to be executed by the controller 200 of the fuel cell vehicle 20. This routine is started when an instruction to start the fuel cell system 30 is entered so that the fuel cell vehicle 20 can drive, in particular when a driver presses or activates a start switch (not shown), and is repeated until a stop instruction is entered (for example, the driver switches the start switch to OFF).

[0042] Fig. Figure 3 is an explanatory figure showing the conditions for starting and stopping the power consumption increase control for the power consumption device in the fuel cell vehicle 20. The power consumption increase control for the power consumption device is described below with reference to Fig. 2 and Fig. 3 described.

[0043] If the power consumption control processing routine of Fig. When step 2 is started, the CPU of controller 200 determines whether the fuel cell vehicle 20 is performing braking power generation, that is, whether the fuel cell vehicle 20 is braking and the drive motor 170 is generating electrical braking power (step S100). If it is determined that braking power generation is not performing (step S100: NO), the CPU of controller 200 terminates this routine.

[0044] If step S100 determines that braking time power generation is performed (step S100: YES), the CPU of controller 200 calculates the vehicle power balance value Wa (step S110). The vehicle power balance value Wa can be calculated using expression (1). In expression (1), the electrical braking time power Wr corresponds to a value estimated, for example, using a vehicle speed with the accelerator pedal deactivated, as the electrical power expected to be generated by the drive motor 170 during braking. Therefore, the electrical braking time power Wr may not be equal to the electrical power actually generated by the drive motor 170.For example, if the vehicle power balance value Wa is positive and excess electrical power is generated as described later, the electrical power actually generated by the drive motor 170 during braking may be less than the electrical braking time span power Wr.

[0045] Once the vehicle power balance value Wa is calculated in step S110, the CPU of controller 200 derives the permissible dischargeable power Wout of the power storage device 650, a first threshold Th1, and a second threshold Th2 (step S120). As described above, the permissible dischargeable power Wout can be determined by sensing the state of charge and temperature of the power storage device 650. The first threshold Th1 corresponds to a reference value of the vehicle power balance value Wa for initiating the power consumption increase control for the power storage device. The second threshold Th2 corresponds to a reference value of the vehicle power balance value Wa for terminating the power consumption increase control for the power storage device after the power consumption increase control has been initiated.The first threshold Th1 and the second threshold Th2 are values ​​determined on the basis of the permissible dischargeable power Wout.

[0046] The power consumption increase control for the power consumption device is designed such that if the electrical braking time interval power Wr generated by the drive motor 170 during braking of the vehicle is excessively large and therefore the vehicle power balance value Wa may be excessively large, the power consumption of the power consumption device mounted on the fuel cell vehicle 20 is greater than the power consumption of the power consumption device at a vehicle power balance value Wa that is less than the second threshold Th2.The power consumption device only needs to consume electrical power 20 during braking of the fuel cell vehicle, and examples of power consumption devices include fuel cell auxiliary devices such as the compressor 130, the coolant pump 525, the radiator fan 535, and the circulation pump 127, as well as vehicle auxiliary devices such as an electric heater configured to heat water to warm the vehicle. Alternatively, a dedicated power consumption device configured to consume the vehicle power balance value Wa can be mounted on the fuel cell vehicle 20.For example, if compressor 130 is used as the power consumption device and is stopped during normal vehicle braking, it is appropriate to start the compressor 130 drive for power consumption increase control and to switch the flow divider valve 144 so that the air supplied by compressor 130 flows completely through the oxidation gas bypass channel 450 without flowing into the fuel cell 100. Therefore, when power consumption increase control is executed, it is appropriate to control the relevant components, if necessary, to reduce the impact on the fuel cell vehicle 20 associated with an increase in the power consumption of the power consumption device.The "power consumption increase control, which is to be implemented such that the power consumption of the power consumption device is greater than the power consumption of the power consumption device at a vehicle power balance value Wa equal to or less than the first threshold Th1," includes a control for initiating the activation of the power consumption device if the power consumption device is stopped before the start of the power consumption increase control. When the power consumption increase control is executed, the activation of the power consumption device is desiredly controlled such that the power consumption of the power consumption device is equal to the vehicle power balance value Wa, that is, the power consumption device consumes excess electrical power obtained by subtracting the vehicle consumption power from the vehicle generation power in the fuel cell vehicle 20.Therefore, the generation and consumption of electrical power in the fuel cell vehicle 20 can be balanced.

[0047] The controller 200 of this embodiment stores a Fig. The characteristic map shown in Figure 3 depicts the relationships between the first threshold Th1 and the permissible discharge power Wout, and between the second threshold Th2 and the permissible discharge power Wout. In step S120, the controller 200 refers to the characteristic map of Fig. 3, to derive the first threshold Th1 and the second threshold Th2 in relation to a value of the allowable dischargeable power Wout at the time of execution of step S120. As in Fig. As shown in Figure 3, in this embodiment the first threshold Th1, which corresponds to the reference value of the vehicle power balance value Wa for starting the power consumption increase control, is set higher than the second threshold Th2, which corresponds to the reference value of the vehicle power balance value Wa for ending the started power consumption increase control. In this embodiment, the power consumption increase control for the power consumption device is started when the vehicle power balance value Wa increases above the first threshold Th1, and is ended when the vehicle power balance value Wa falls below the second threshold Th2 after the start of the power consumption increase control. As shown in Fig. As shown in Figure 3, a hysteresis is set between the first threshold Th1 and the second threshold Th2. Therefore, a hunting effect during operation for starting and stopping the power consumption increase control can be suppressed. The difference between the first threshold Th1 and the second threshold Th2 does not need to be constant across the entire range of permissible discharge power Wout. It is only required that the first threshold Th1 is greater than the second threshold Th2.

[0048] In this embodiment, as in Fig. As shown in Figure 3, a first threshold Th1 at a permissible discharge power Wout that is less than a predetermined first reference power value W1 is greater than a first threshold Th1 at a permissible discharge power Wout that is greater than the first reference power value W1. A second threshold Th2 at a permissible discharge power Wout that is less than the first reference power value W1 is greater than a second threshold Th2 at a permissible discharge power Wout that is greater than the first reference power value W1. In particular, in this embodiment, a first threshold Th1 at a permissible discharge power Wout that is less than the first reference power value W1 and greater than a second reference power value W2 that is less than the first reference power value W1 increases with decreasing permissible discharge power Wout.A second threshold Th2 at the permissible dischargeable power Wout, which is smaller than the first reference power value W1 and larger than the second reference power value W2, increases with decreasing permissible dischargeable power Wout.

[0049] After the permissible dischargeable power Wout, the first threshold Th1, and the second threshold Th2 are derived in step S120, the CPU of controller 200 determines whether the fuel cell vehicle 20 is already executing the power consumption increase control (step S130). If it is determined that the power consumption increase control is not executing (step S130: NO), the CPU of controller 200 determines whether the vehicle power balance value Wa is greater than the first threshold Th1 (step S140). If it is determined that the vehicle power balance value Wa is equal to or less than the first threshold Th1 (step S140: NO), the CPU of controller 200 terminates this routine. Therefore, the power consumption increase control remains inactive.If it is determined that the vehicle power balance value Wa is greater than the first threshold Th1 (step S140: YES), the CPU of controller 200 starts the power consumption increase control (step S150) and then terminates this routine. Starting the power consumption increase control causes the power consumption device to begin consuming electrical power, or the power consumption of the power consumption device is greater than it was before the power consumption increase control started.

[0050] If step S130 determines that the power consumption increase control is executed (step S130: YES), the CPU of controller 200 determines whether the vehicle power balance value Wa is less than the second threshold Th2 (step S160). If it determines that the vehicle power balance value Wa is equal to or greater than the second threshold Th2 (step S160: NO), the CPU of controller 200 terminates this routine. Thus, the power consumption increase control remains executed. If it determines that the vehicle power balance value Wa is less than the second threshold Th2 (step S160: YES), the CPU of controller 200 terminates the power consumption increase control (step S170) and then ends this routine. By terminating the power consumption increase control, the power consumption device stops consuming electrical power, or the power consumption of the power consumption device is reduced.

[0051] According to the fuel cell vehicle 20 of this embodiment, which is configured as described above, when executing the power consumption increase control to cause the power consumption device to consume excess electrical power of the vehicle during braking, the second threshold Th2, which corresponds to the reference value of the vehicle power balance value Wa for terminating the power consumption increase control, is set lower than the first threshold Th1, which corresponds to the reference value of the vehicle power balance value Wa for initiating the power consumption increase control, and the hysteresis is set between the first threshold Th1 and the second threshold Th2. The first threshold Th1 and the second threshold Th2 at the permissible dischargeable power Wout of the power storage device 650, which is lower than the first reference power value W1, are higher than the first threshold Th1 and the second threshold Th2, respectively.The second threshold Th2 at the permissible dischargeable power Wout is equal to or greater than the first reference power value W1. Therefore, the generation and consumption of electrical power in the fuel cell vehicle 20 can be further balanced even if the required power of the vehicle or the state of the power storage device 650 varies when the power consumption increase control is executed.

[0052] In particular, when the vehicle power balance value Wa is positive, that is, when the vehicle has excess electrical power and the power consumption increase control for the power consumption device is executing, and when the permissible dischargeable power Wout of the power storage device 650 is less than the first reference power value W1, the power consumption increase control can terminate more quickly in response to a decrease in the vehicle power balance value Wa to a negative value. As a result, a deficit of electrical power in the fuel cell vehicle 20 is suppressed when the vehicle power balance value Wa changes to a negative value. Therefore, the generation and consumption of electrical power can be further balanced.

[0053] Fig. Figure 4 is an explanatory illustration showing the conditions for starting and stopping the power consumption increase control in a comparative example. Fig. 4 is the first threshold Th1, which corresponds to the reference value of the vehicle power balance value Wa for starting the power consumption increase control, set to zero regardless of the value of the permissible dischargeable power Wout. The second threshold Th2, which corresponds to the reference value of the vehicle power balance value Wa for ending the power consumption increase control, is set to a constant negative value Wa2, regardless of the value of the permissible dischargeable power Wout.

[0054] If the permissible discharge power Wout is relatively large, especially if the permissible discharge power Wout is greater than the first reference power value W1, the first threshold Th1 is equal to zero and the second threshold Th2 corresponds to the value Wa2, both in this and Fig. 3 embodiment as well as in the embodiment shown in Fig. 4. In the comparative example shown, if the vehicle power balance value Wa is positive and the vehicle has excess electrical power, the power consumption increase control is initiated because the vehicle power balance value Wa becomes greater than the first threshold Th1. Therefore, the power consumption device can consume the excess electrical power. If the vehicle power balance value Wa falls to a negative value after the power consumption increase control has been initiated, the power consumption increase control will not terminate unless the vehicle power balance value Wa falls to the value Wa2, which corresponds to the second threshold Th2. Therefore, the electrical power of the fuel cell vehicle 20 is insufficient.If the permissible dischargeable power Wout is greater than the first reference power value W1, the permissible dischargeable power Wout is relatively large, and therefore the electrical power can be supplied by discharging from the power storage device 650 in accordance with the negative vehicle power balance value Wa. Therefore, the generation and consumption of electrical power in the fuel cell vehicle 20 can be balanced.

[0055] If the permissible dischargeable power Wout is relatively small, in particular if the permissible dischargeable power Wout is less than the first reference power value W1, the first threshold Th1 is greater than zero and the second threshold Th2 is greater than the value Wa2 in this embodiment. If, in the fuel cell vehicle 20 of this embodiment, the vehicle power balance value Wa decreases after the start of the power consumption increase control for the power consumption device, the vehicle power balance value Wa falls to the second threshold Th2 more quickly than in the comparative example of Fig. 4. Therefore, the power consumption increase control can be terminated. This allows a shortfall in electrical power in the fuel cell vehicle 20 to be suppressed and the generation and consumption of electrical power to be balanced.

[0056] If the vehicle power balance value Wa is negative until the power consumption increase control is terminated after its initiation, it may be more difficult for the power storage device 650 to supply electrical power corresponding to the deficit in the fuel cell vehicle 20, that is, to the vehicle power balance value Wa, when the permissible dischargeable power Wout decreases. In this embodiment, if the permissible dischargeable power Wout is less than the first reference power value W1 and greater than the second reference power value W2, which is less than the first reference power value W1, the second threshold Th2 is set to a larger value when the permissible dischargeable power Wout decreases.When the permissible dischargeable power Wout decreases, the shortfall in electrical power in the fuel cell vehicle 20 is suppressed due to the execution of the power consumption increase control before the power consumption increase control is terminated. Therefore, the generation and consumption of electrical power can be balanced.

[0057] If the permissible dischargeable power Wout is particularly low, that is, equal to or less than the second reference power value W2, the second threshold Th2 is zero, which corresponds to the maximum value. If the vehicle power balance value Wa drops to zero after the power consumption increase control has been initiated, the power consumption increase control can be terminated immediately. Therefore, the shortfall in electrical power in the fuel cell vehicle 20 is suppressed when discharging from the power storage device 650 is difficult. Thus, the generation and consumption of electrical power can be balanced. In this embodiment, if the permissible dischargeable power Wout is equal to or less than the second reference power value W2, the first threshold Th1 corresponds to a maximum positive value Wa1.

[0058] In this embodiment, if the permissible dischargeable power Wout is less than the first reference power value W1, the electrical power of the fuel cell vehicle 20 is excessive unless the vehicle power balance value Wa rises above zero to reach the first threshold Th1, and the power consumption increase control is initiated. At this time, the power storage device 650 can be charged with the excess electrical power of the fuel cell vehicle 20, provided the excess is equal to or less than the permissible chargeable power Win of the power storage device 650. The excess electrical power can be reduced by a control system to reduce the vehicle power balance value Wa. In particular, it is appropriate to reduce the electrical power to be generated by the drive motor 170 during braking.If the electrical power to be generated by the drive motor 170 is reduced, but the braking force to be generated in the braking time-span power generation mode falls to an unacceptable level, it is appropriate, for example, for the controller 200 to perform a control to increase the braking forces of friction brakes (not shown) mounted on the fuel cell vehicle 20.

[0059] In Fig. 3. The first reference power value W1, the second reference power value W2, the value Wa2 which corresponds to the second threshold Th2 at the permissible dischargeable power Wout equal to the first reference power value W1, and the maximum value Wa1 of the first threshold Th1 at the permissible dischargeable power Wout equal to or less than the second reference power value W2, if necessary taking into account, for example, an estimated maximum value of the auxiliary device power consumption We of the fuel cell vehicle 20 during braking of the vehicle, an estimated maximum value of the electrical power to be generated by the drive motor 170 during braking, and charging / discharging characteristics of the power storage device 650, can be set.

[0060] As in Fig. As shown in Figure 3, in this embodiment the second threshold Th2 is equal to zero, which corresponds to the maximum value when the permissible dischargeable power Wout is equal to or less than the second reference power value W2. However, a different configuration can be used. For example, a value greater than zero can be set as the maximum value of the second threshold Th2. In this configuration, the power consumption increase control is terminated more immediately if the vehicle power balance value Wa decreases after the start of the power consumption increase control, while the permissible dischargeable power Wout is relatively small. Therefore, it is possible to enhance the effect of suppressing the shortfall in electrical power and balancing the generation and consumption of electrical power.

[0061] In this embodiment, the first threshold Th1 and the second threshold Th2 increase with decreasing permissible discharge power Wout when the first reference power W1 is less than the first reference power W1 and the second reference power W2 is less than the first reference power W1. However, a different configuration can be used. The present invention is not limited to the case where the first threshold Th1 and the second threshold Th2 gradually increase with decreasing permissible discharge power Wout. It is only necessary that the first threshold Th1 and the second threshold Th2 are greater when the permissible discharge power Wout is less than the first reference power W1, and that the second threshold Th2 is greater when the permissible discharge power Wout is equal to or greater than the first reference power W1.

[0062] In this embodiment, the second threshold Th2 corresponds to the constant value Wa2 when the permissible dischargeable power Wout is equal to or greater than the first reference power value W1; however, a different configuration can be used. For example, if the permissible dischargeable power Wout is equal to or greater than the first reference power value W1, the second threshold Th2 can gradually decrease as the permissible dischargeable power Wout increases. If the permissible dischargeable power Wout is large, electrical power can be easily supplied from the power storage device 650, even if the vehicle power balance value Wa decreases during the execution of the power consumption increase control. Furthermore, the effect of suppressing overrun can be enhanced by setting a larger hysteresis. B. Second embodiment

[0063] Fig. Figure 5 is a flowchart representing a threshold change control processing routine to be executed by a controller 200 of a fuel cell vehicle 20 according to a second embodiment of the present invention. This routine is started when an instruction to start a fuel cell system 30 is entered, enabling the fuel cell vehicle 20 to drive, and is executed in parallel to the routine described in Figure 5. Fig. The power consumption control processing routine shown in section 2 is repeated until a stop instruction is entered. The fuel cell vehicle 20 of the second embodiment has a similar configuration to that of the first embodiment.

[0064] When this routine is started, the CPU of controller 200 determines whether the fuel cell vehicle 20 performs braking time power generation (step S200). Step S200 involves the same operation as in step S100 of Fig. 2. If it is determined that braking time span power generation will not be performed (step S200: NO), the CPU of controller 200 terminates this routine.

[0065] If step S200 determines that braking time span power generation is being executed (step S200: YES), the CPU of controller 200 determines whether the fuel cell vehicle 20 is already executing power consumption increase control (step S210). If it determines that power consumption increase control is being executed (step S210: YES), the CPU of controller 200 terminates this routine.

[0066] If step S210 determines that the power consumption increase control is not executed (step S210: NO), the CPU of controller 200 obtains an elapsed time ta from a previous termination of the power consumption increase control (step S220). Controller 200 of this embodiment includes a timer for measuring the elapsed time ta since the termination of the power consumption increase control.

[0067] When the elapsed time ta is reached, the CPU of controller 200 compares the elapsed time ta with a predetermined first reference time T1 (step S230). If the elapsed time ta is shorter than the first reference time T1 (step S230: NO), the CPU of controller 200 terminates this routine.

[0068] If step S230 determines that the elapsed time ta is equal to or greater than the first reference time T1 (step S230: YES), the CPU of controller 200 sets the first threshold Th1 to zero (step S240) and then terminates this routine. If the first threshold Th1, related to the allowable discharge power Wout, is zero at the time step S240 is executed (the allowable discharge power Wout is equal to or greater than the first reference power value W1), the first threshold Th1 is held at zero in step S240. If the first threshold Th1, related to the allowable discharge power Wout, is greater than zero at the time step S240 is executed (the allowable discharge power Wout is less than the first reference power value W1), the first threshold Th1 is changed to zero in step S240.If the first threshold Th1 is changed to zero in step S240, the power consumption control processing routine is then executed. Fig. 2 using zero as the first threshold Th1 to determine whether to start the power consumption increase control.

[0069] In this embodiment, when the first threshold Th1 is changed to zero in step S240, the first threshold Th1 is reset on each execution of the threshold change control processing routine. Fig. 5 is held at zero until the power consumption increase control is subsequently started. When the power consumption increase control is executed using the first threshold Th1, which is set to zero, the first threshold Th1 is reset, and normal control is resumed using the value in Fig. The characteristic curve shown in section 3 is then executed.

[0070] This configuration makes it possible to reduce the occurrence of a situation where the power consumption increase control is not activated and the electrical power of the fuel cell vehicle 20 remains excessively high because the vehicle power balance value Wa is positive. This is particularly relevant when the power consumption increase control is not activated and the vehicle power balance value Wa is within a hatched area in Fig. If step 3 remains, the power consumption increase control can be started at an elapsed time ta that reaches the first reference time T1. Thus, even if the vehicle power balance value Wa remains positive (unless the first threshold Th1 is changed to zero in step S240), an excessive increase in electrical power can be suppressed by starting the power consumption increase control for the power consumption device. The first reference time T1 can optionally be set, for example, based on the characteristic of the permissible chargeable power Win of the power storage device 650 or the maximum value Wa1 of the first threshold Th1. C. Third embodiment

[0071] Fig. Figure 6 is a flowchart representing a threshold change control processing routine to be executed by a controller 200 of a fuel cell vehicle 20 according to a third embodiment of the present invention. This routine is executed instead of the threshold change control processing routine of the second embodiment. The fuel cell vehicle 20 of the third embodiment has a similar configuration to that of the first embodiment.

[0072] When this routine is started, the CPU of controller 200 determines whether the fuel cell vehicle 20 is performing braking time power generation (step S300). If it is determined that braking time power generation is being performed (step S300: YES), the CPU of controller 200 determines whether the fuel cell vehicle 20 is already performing power consumption increase control (step S310). Steps S300 and S310 are executed similarly to steps S200 and S210 of the second embodiment.

[0073] If step S310 determines that the power consumption increase control is not executed (step S310: NO), the CPU of controller 200 obtains the vehicle power balance value Wa determined from expression (1) (step S320). The CPU of controller 200 determines whether the vehicle power balance value Wa is equal to or greater than the second threshold Th2 and equal to or less than the first threshold Th1 (step S330). If "Th2 ≤ Wa ≤ Th1" is not true (step S330: NO), the CPU of controller 200 terminates this routine.

[0074] If “Th2 ≤ Wa ≤ Th1” is satisfied in step S330 (step S330: YES), the CPU of controller 200 obtains an elapsed time tb, which indicates the continuation of a state in which the power consumption increase control is not executed and “Th2 ≤ Wa ≤ Th1” is satisfied (step S340). Controller 200 of this embodiment includes a timer for measuring the elapsed time tb from the fulfillment of “Th2 ≤ Wa ≤ Th1”.

[0075] When the elapsed time tb is reached, the CPU of controller 200 compares the elapsed time tb with a predetermined second reference time T2 (step S350). If the elapsed time tb is shorter than the second reference time T2 (step S350: NO), the CPU of controller 200 terminates this routine.

[0076] If step S350 determines that the elapsed time tb is equal to or longer than the second reference time T2 (step S350: YES), the CPU of controller 200 sets the first threshold Th1 to zero (step S360) and then terminates this routine. Step S360 involves a similar operation to that in step S240. When the first threshold Th1 is changed to zero, the power consumption control processing routine is subsequently executed. Fig. 2 using zero as the first threshold Th1 to determine whether to start the power consumption increase control.

[0077] In this embodiment, if the first threshold Th1 is changed to zero in step S360, the first threshold Th1 is reset on each execution of the threshold change control processing routine. Fig. 6 is held at zero until the power consumption increase control is subsequently started. If the power consumption increase control is executed using the first threshold Th1, which is set to zero, then "Th2 ≤ Wa ≤ Th1" is not satisfied. Therefore, the elapsed time tb and the first threshold Th1 are reset, and then normal control is initiated using the value in Fig. 3 characteristic curve shown.

[0078] With this configuration, a similar effect to that of the second embodiment can be achieved. The second reference time T2 can optionally be set, for example, based on the characteristic of the permissible chargeable power Win of the power storage device 650 or the maximum value Wa1 of the first threshold Th1. D. Fourth embodiment

[0079] Fig. Figure 7 is a flowchart representing a threshold change control processing routine to be executed by a controller 200 of a fuel cell vehicle 20 according to a fourth embodiment of the present invention. This routine is started when an instruction to start a fuel cell system 30 is entered so that the fuel cell vehicle 20 can drive, and is executed in parallel to the one described in Figure 7. Fig. The power consumption control processing routine shown in section 2 is repeated until a stop instruction is entered. The fuel cell vehicle 20 of the fourth embodiment has a similar configuration to that of the first embodiment.

[0080] When this routine is started, the CPU of controller 200 determines whether the fuel cell vehicle 20 is performing braking time power generation (step S400). If it is determined that braking time power generation is performing (step S400: YES), the CPU of controller 200 determines whether the fuel cell vehicle 20 is already performing power consumption increase control (step S410). Steps S400 and S410 are executed similarly to steps S200 and S210 of the second embodiment.

[0081] If step S410 determines that the power consumption increase control will not be executed (step S410: NO), the CPU of controller 200 terminates this routine. If step S410 determines that the power consumption increase control will be executed (step S410: YES), the CPU of controller 200 obtains an elapsed time tc from a previous start of the power consumption increase control (step S420). Controller 200 of this embodiment includes a timer for measuring the elapsed time tc from the start of the power consumption increase control.

[0082] When the elapsed time tc is reached, the CPU of controller 200 compares the elapsed time tc with a predetermined third reference time T3 (step S430). If the elapsed time tc is shorter than the third reference time T3 (step S430: NO), the CPU of controller 200 terminates this routine.

[0083] If step S430 determines that the elapsed time tc is equal to or greater than the third reference time T3 (step S430: YES), the CPU of controller 200 sets the second threshold Th2 to zero (step S440) and then terminates this routine. If the second threshold Th2, related to the allowable discharge power Wout, is zero at the time step S440 is executed (the allowable discharge power Wout is equal to or less than the second reference power value W2), the second threshold Th2 is held at zero in step S440. If the second threshold Th2, related to the allowable discharge power Wout, is less than zero at the time step S440 is executed (the allowable discharge power Wout is greater than the second reference power value W2), the second threshold Th2 is changed to zero in step S440.When the second threshold Th2 is changed to zero in step S440, the power consumption control processing routine is executed. Fig. 2 subsequently performed using zero as the second threshold Th2 to determine whether to terminate the power consumption increase control.

[0084] In this embodiment, if the second threshold Th2 is changed to zero in step S440, the second threshold Th2 is reset on each execution of the threshold change control processing routine. Fig. 7 is held at zero until the power consumption increase control is subsequently terminated. When the power consumption increase control is terminated using the second threshold Th2 set to zero, the second threshold Th2 is reset, and normal control is resumed using the value in Fig. The characteristic curve shown in section 3 is then executed.

[0085] This configuration makes it possible to reduce the occurrence of a situation where the power consumption enhancement control is not terminated and the electrical power of the fuel cell vehicle 20 remains insufficient because the vehicle power balance value Wa is negative. Specifically, if the power consumption enhancement control is not terminated and the vehicle power balance value Wa remains negative, the power consumption enhancement control can be terminated after a time tc has elapsed, which reaches the third reference time T3. Thus, even in a case where the vehicle power balance value Wa can remain negative, provided the second threshold Th2 in step S440 is not changed to zero, the shortfall in electrical power due to the power consumption of the power consumption device can be suppressed by terminating the power consumption enhancement control for the power consumption device.The third reference time T3 may, for example, be set on the basis of the characteristic of the permissible dischargeable power Wout of the power storage device 650 or the minimum value Wa2 of the second threshold Th2. E. Fifth embodiment

[0086] Fig. Figure 8 is a flowchart representing a threshold change control processing routine to be executed by a controller 200 of a fuel cell vehicle 20 according to a fifth embodiment of the present invention. This routine is executed instead of the threshold change control processing routine of the fourth embodiment. The fuel cell vehicle 20 of the fifth embodiment has a similar configuration to that of the first embodiment.

[0087] When this routine is started, the CPU of controller 200 determines whether the fuel cell vehicle 20 is performing braking time power generation (step S500). If it is determined that braking time power generation is performing (step S500: YES), the CPU of controller 200 determines whether the fuel cell vehicle 20 is already performing power consumption increase control (step S510). Steps S500 and S510 are executed similarly to steps S400 and S410 of the fourth embodiment.

[0088] If step S510 determines that the power consumption increase control is executed (step S510: YES), the CPU of controller 200 obtains the vehicle power balance value Wa determined from expression (1) (step S520). The CPU of controller 200 determines whether the vehicle power balance value Wa is equal to or greater than the second threshold Th2 and equal to or less than the first threshold Th1 (step S530). If "Th2 ≤ Wa ≤ Th1" is not true (step S530: NO), the CPU of controller 200 terminates this routine.

[0089] If "Th2 ≤ Wa ≤ Th1" is satisfied in step S530 (step S530: YES), the CPU of controller 200 obtains an elapsed time td, which indicates the continuation of a state in which "Th2 ≤ Wa ≤ Th1" is satisfied after the start of the power consumption increase control (step S540). Controller 200 of this embodiment includes a timer for measuring the elapsed time td from the fulfillment of "Th2 ≤ Wa ≤ Th1" after the start of the power consumption increase control.

[0090] When the elapsed time td is reached, the CPU of controller 200 compares the elapsed time td with a predetermined fourth reference time T4 (step S550). If the elapsed time td is shorter than the fourth reference time T4 (step S550: NO), the CPU of controller 200 terminates this routine.

[0091] If step S550 determines that the elapsed time td is equal to or greater than the fourth reference time T4 (step S550: YES), the CPU of controller 200 sets the second threshold Th2 to zero (step S560) and then terminates this routine. Step S560 involves a similar operation to that in step S440. When the second threshold Th2 is changed to zero, the power consumption control processing routine is subsequently executed. Fig. 2 using zero as the second threshold Th2 to determine whether to terminate the power consumption increase control.

[0092] In this embodiment, if the second threshold Th2 is changed to zero in step S560, the second threshold Th2 is reset on each execution of the threshold change control processing routine. Fig. 8 is held at zero until the power consumption increase control is subsequently terminated. When the power consumption increase control is terminated using the second threshold Th2 set to zero, "Th2 ≤ Wa ≤ Th1" is not satisfied. Therefore, the elapsed time td and the second threshold Th2 are reset, and normal control is resumed using the value in Fig. The characteristic curve shown in section 3 is then executed.

[0093] With this configuration, a similar effect to that of the fourth embodiment can be achieved. The fourth reference time T4 can optionally be set, for example, based on the characteristic of the permissible dischargeable power Wout of the power storage device 650 or the minimum value Wa2 of the second threshold Th2. F. Other embodiments

[0094] (F1) In the embodiments described above, whether to start or stop the power consumption increase control for the power consumption device is determined by using only the permissible dischargeable power Wout as a value indicating the state of the power storage device 650. Another configuration may be used. For example, the permissible chargeable power Win may also be used. In particular, if in step S130 of the power consumption control processing routine of Fig.If it is determined that the power consumption increase control will not be executed (step S130: NO), the vehicle power balance value Wa can be compared with the permissible chargeable power Win. This routine can be terminated if the permissible chargeable power Win is equal to or greater than the vehicle power balance value Wa. The determination in step S140 can be performed if the permissible chargeable power Win is less than the vehicle power balance value Wa. The power consumption increase control can be started if the vehicle power balance value Wa is greater than the first threshold Th1.The above-described process can be carried out because, if the permissible chargeable power Win is equal to or greater than the vehicle power balance value Wa, an excessive increase in the electrical power of the fuel cell vehicle 20 can be suppressed by charging the power storage device 650 with electrical power corresponding to the vehicle power balance value Wa.

[0095] (F2) In the embodiments described above, the operation of the fuel cell vehicle 20 is described as an example of a hybrid vehicle comprising a power storage device and an electric generator configured to generate electrical power for propelling the vehicle as a drive power source for the vehicle. The present invention can be applied to various types of hybrid vehicles. In particular, the hybrid vehicle can comprise an internal combustion engine, such as a machine, and a power-generating motor configured to generate electrical power by utilizing the drive power generated by the internal combustion engine, instead of the fuel cell 100 as the electric generator configured to generate electrical power for propelling the vehicle.Even in this hybrid vehicle, similar effects to these are achieved in the respective embodiments, as long as a control similar to these in the embodiments is implemented for determining using the vehicle power balance value Wa to start or stop the power consumption increase control for the power consumption device when the electric generator stops generating electrical power during braking of the vehicle and the drive motor operates in braking time power generation mode.

[0096] The present invention can be implemented in various forms other than the device. The present invention can also be implemented in various forms, such as a method for controlling a hybrid vehicle, a computer program for implementing the control method, and a non-volatile recording medium for storing the computer program.

[0097] The technical features of the embodiments, corresponding to the technical features of the respective aspects described in the section “Abstract of the Invention”, can optionally be replaced or combined to solve some or all of the problems described above or to achieve some or all of the effects described above.

Claims

[1] Hybrid vehicle, comprising: an electric generator (100) which is configured to generate electrical power to drive the hybrid vehicle; a drive motor (170) which is configured to operate in a power driving mode in which the drive motor (170) drives the hybrid vehicle, or in a braking time power generation mode in which the drive motor (170) generates electrical braking time power by operating as a generator and generates a braking force for the hybrid vehicle; a power storage device (650) configured to store the electrical power generated by the electric generator (100) and the electrical braking time interval power generated by the drive motor (170); a power-consuming device (130; 525; 535; 127) configured to consume electrical power; and a controller (200) which is configured to control the control of the power consumption device (130; 525; 535; 127), wherein the controller (200) is configured to perform a power consumption increase control when a vehicle power balance value (Wa) is greater than a first threshold (Th1) while the drive motor (170) is operating in the braking time span power generation mode, the vehicle power balance value (Wa) corresponds to a vehicle power balance value that does not include any charging and discharging amount of the power storage device (650) and is obtained by subtracting a vehicle consumption power consumed by the hybrid vehicle from a vehicle generation power, the vehicle generation power corresponds to an electrical power generated by the hybrid vehicle, including an estimated value of the electrical braking time span power, the power consumption increase control of a control for setting a power consumption of the power consumption device (130; 525; 535; 127) to a greater value than the power consumption of the power consumption device (130; 525; 535; 127) at the vehicle power balance value (Wa), which is less than a second threshold (Th2) that is set less than the first threshold (Th1), corresponds to the first threshold (Th1) is preset on the basis of a permissible dischargeable power (Wout), which is determined as an upper limit of the electrical power to be discharged by the power storage device (650) depending on a state of the power storage device (650), the first threshold (Th1) at the permissible dischargeable power (Wout), which is less than a predetermined first reference power value (W1), is set higher than the first threshold (Th1) at the permissible dischargeable power (Wout), which is equal to or greater than the first reference power value (W1), the second threshold (Th2) at the permissible discharge power (Wout), which is less than the first reference power value (W1), is set higher than the second threshold (Th2) at the permissible discharge power (Wout), which is equal to or greater than the first reference power value (W1), and the controller (200) is configured to terminate the power consumption increase control when the vehicle power balance value (Wa) is less than the second threshold (Th2) after a start of the power consumption increase control. [2] Hybrid vehicle according to claim 1, wherein the first threshold (Th1) at the permissible discharge power (Wout), which is smaller than the first reference power value (W1) and larger than a second reference power value (W2), which is smaller than the first reference power value (W1), is set such that it increases with decreasing permissible discharge power (Wout), and The second threshold (Th2) at the permissible discharge power (Wout), which is smaller than the first reference power value (W1) and larger than the second reference power value (W2), is set such that it increases with decreasing permissible discharge power (Wout). [3] Hybrid vehicle according to claim 1 or 2, wherein the controller (200) is configured such that if a predetermined first reference time (T1) elapses without starting the power consumption increase control after a termination of the power consumption increase control, the first threshold (Th1) is set to zero until the power consumption increase control is subsequently started. [4] Hybrid vehicle according to claim 1 or 2, wherein the controller (200) is configured such that if a predetermined second reference time (T2) or longer elapses while the vehicle power balance value (Wa) remains equal to or greater than the second threshold (Th2) and equal to or less than the first threshold (Th1) without executing the power consumption increase control, the first threshold (Th1) is set to zero until the power consumption increase control is subsequently started. [5] Hybrid vehicle according to one of claims 1 to 4, wherein the controller (200) is configured such that if a predetermined third reference time (T3) elapses without the power consumption increase control being terminated after a start of the power consumption increase control, the second threshold (Th2) is set to zero until the power consumption increase control is subsequently terminated. [6] Hybrid vehicle according to any one of claims 1 to 4, wherein the controller (200) is configured such that if a predetermined fourth reference time (T4) or longer elapses while the vehicle power balance value (Wa) remains equal to or greater than the second threshold (Th2) and equal to or less than the first threshold (Th1) during the execution of the power consumption increase control, the second threshold (Th2) is set to zero until the power consumption increase control is subsequently terminated. [7] Method for controlling a hybrid vehicle, wherein the hybrid vehicle comprises an electric generator (100) configured to generate electrical power for driving the hybrid vehicle, a drive motor (170) configured to operate in a power driving mode in which the drive motor (170) drives the hybrid vehicle, or in a braking power generation mode in which the drive motor (170) generates electrical braking power by operating as a generator and provides braking force for the hybrid vehicle, a power storage device (650) configured to store the electrical power generated by the electric generator (100) and the electrical braking power generated by the drive motor (170), and a power consumption device (130; 525; 535;127), which is configured to consume this electrical power, comprising the method for controlling the hybrid vehicle:; Executing a power consumption increase control when a vehicle power balance value (Wa) is greater than a first threshold (Th1) while the drive motor (170) is operating in the braking time span power generation mode, wherein the vehicle power balance value (Wa) corresponds to a vehicle power balance value that does not include any charging and discharging amount of the power storage device (650) and is obtained by subtracting a vehicle consumption power consumed by the hybrid vehicle from a vehicle generation power, where the vehicle generation power corresponds to an electrical power generated by the hybrid vehicle including an estimated value of the electrical braking time span power, wherein the power consumption increase control corresponds to a control for setting a power consumption of the power consumption device (130; 525; 535; 127) to a greater value than the power consumption of the power consumption device (130; 525; 535; 127) at the vehicle power balance value (Wa), which is less than a second threshold (Th2) that is set less than the first threshold (Th1), wherein the first threshold (Th1) is preset on the basis of a permissible dischargeable power (Wout) which is determined as an upper limit of the electrical power to be discharged by the power storage device (650) depending on a state of the power storage device (650), wherein the first threshold (Th1) at the permissible dischargeable power (Wout) which is less than a predetermined first reference power value (W1) is set higher than the first threshold (Th1) at the permissible dischargeable power (Wout) which is equal to or greater than the first reference power value (W1), wherein the second threshold (Th2) at the permissible discharge power (Wout) which is less than the first reference power value (W1) is set higher than the second threshold (Th2) at the permissible discharge power (Wout) which is equal to or greater than the first reference power value (W1); and Terminate the power consumption increase control if the vehicle power balance value (Wa) becomes less than the second threshold (Th2) after a start of the power consumption increase control.

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