JP2015065718A - Fuel cell vehicle and fuel cell vehicle control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily generate heat for defrosting and defogging of a fuel cell vehicle.SOLUTION: A fuel cell vehicle includes: a fuel cell; a fuel-cell cooling circuit that cools the fuel cell; a water circuit for heating used to heat a vehicle cabin of the fuel cell vehicle; a valve that controls supply of cooling water from the fuel-cell cooling circuit to the water circuit for heating; a defroster that defrosts windows of the fuel cell vehicle using heat of the cooling water in the water circuit for heating; and a control unit that controls the fuel cell vehicle to operate. The control unit executes a first control to control the defroster to execute defrosting by reducing power generation efficiency of the fuel cell as compared with a case of no defrosting request to generate heat from the fuel cell, and by opening the valve to move the heat from the fuel-cell cooling circuit to the cooling water in the water circuit for heating if a defrosting request is received, and executes a second control higher than the first control in the power generation efficiency of the fuel cell if no defrosting request is received.

Description

  The present invention relates to a fuel cell vehicle and a fuel cell vehicle control method.

  When people get into the vehicle when the outside temperature is low, such as in winter, the window glass tends to be cloudy. The fogging of the window glass occurs when water vapor in the vehicle comes into contact with the window glass cooled by the outside air to condense. Also, in the early morning, frost may adhere to the window glass cooled by the temperature drop at night or by radiative cooling. Generally, when frost adheres to the window glass or becomes cloudy, a person activates the defroster, blows warm air on the window glass, and warms the window glass to remove frost or cloudiness. By the way, there is known a fuel cell vehicle including a heater core that heats air for air conditioning using cooling water of a cooling circuit (fuel cell cooling circuit) for cooling the fuel cell of the fuel cell vehicle as a heat source (for example, Patent Document 1). . In this fuel cell vehicle, a part of the air-conditioning air is blown out from the defroster and used to remove frost and fog on the window glass.

JP2013-14268A

  However, immediately after the start of the fuel cell vehicle (fuel cell), the temperature of the cooling water in the fuel cell cooling circuit is low because the fuel cell is not warmed. As a result, there is a problem that air for air conditioning cannot be heated using the cooling water of the cooling circuit for the fuel cell as a heat source, and it is difficult to blow warm air onto the window glass.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

(1) According to one aspect of the present invention, a fuel cell vehicle is provided. The fuel cell vehicle includes a fuel cell, a fuel cell cooling circuit for cooling the fuel cell, a heating water circuit used for heating the interior of the fuel cell vehicle, and the heating from the fuel cell cooling circuit. A valve for controlling the supply of cooling water to the water circuit, a defroster for defrosting the window of the fuel cell vehicle using heat of the cooling water of the heating water circuit, and a control for controlling the operation of the fuel cell vehicle A section. When the control unit receives a defrost request, the control unit lowers the power generation efficiency of the fuel cell compared to a case where the defrost request is not received, and heats the fuel cell, opens the valve, and heats the fuel cell. Is moved from the fuel cell cooling circuit to the cooling water of the heating water circuit, the first control is executed to cause the defroster to execute the defrost, and when the defrost request is not received, the first control is performed. The second control with higher power generation efficiency of the fuel cell is executed than the control in step (b). According to the fuel cell vehicle of this embodiment, when a defrost request is received, heat is generated in the fuel cell by causing the power generation efficiency of the fuel cell to be lower than in normal operation not receiving the defrost request. And opens the valve to transfer heat from the fuel cell cooling circuit to the cooling water in the heating water circuit, so it is easier to generate defrost heat than when maintaining the power generation efficiency of the fuel cell during normal operation. It becomes possible to make it.

(2) The fuel cell vehicle of the above aspect further includes a fuel gas circuit that supplies fuel gas to the fuel cell, and an oxidant gas circuit that supplies oxidant gas to the fuel cell. By increasing the current of the fuel cell while maintaining the amounts of the fuel gas and the oxidizing gas supplied to the fuel cell, the power generation efficiency of the fuel cell may be lowered to raise the temperature. According to the fuel cell vehicle of this embodiment, the power generation efficiency of the fuel cell is lowered by increasing the current of the fuel cell while maintaining the amounts of the fuel gas and the oxidizing gas supplied to the fuel cell. As a result, a part of electric energy can be generated as thermal energy.

(3) The fuel cell vehicle according to the above aspect further includes an auxiliary machine, and the control unit increases the loss of the auxiliary machine to increase the current of the fuel cell, thereby reducing the power generation efficiency of the fuel cell. You may let them. According to the fuel cell vehicle of this aspect, the current can be increased by increasing the loss due to the auxiliary equipment.

(4) In the fuel cell vehicle according to the above aspect, the fuel cell cooling circuit includes a water pump that circulates cooling water, and the fuel gas circuit circulates the fuel gas discharged from the fuel cell to circulate the fuel cell. The control unit may reduce the power generation efficiency of the fuel cell by increasing an auxiliary machine loss of at least one of the water pump and the hydrogen pump. According to the fuel cell vehicle of this embodiment, the power generation efficiency of the fuel cell can be reduced by increasing the current loss by increasing the auxiliary machine loss of at least one of the water pump and the hydrogen pump. Moreover, the current of the fuel cell can be increased by supplying hydrogen to the fuel cell with a hydrogen pump. Further, since the water pump is in contact with the cooling water, the heat generated in the water pump due to the loss of the water pump can be directly transferred to the cooling water.

(5) The fuel cell vehicle of the above aspect further includes an outside air temperature sensor, and when the outside air temperature is equal to or lower than a predetermined temperature, the control unit performs the first control in response to the defrost request. When the outside air temperature exceeds a predetermined temperature, the control unit may execute the second control even when there is the defrost request. Although driving with reduced power generation efficiency of the fuel cell deteriorates fuel consumption, according to the fuel cell vehicle of this embodiment, the first control is executed when the outside air temperature is equal to or lower than a predetermined temperature. Defrosting can be performed without deteriorating the fuel consumption of the battery vehicle.

  The present invention can be realized in various forms, for example, in the form of a control method in the fuel cell vehicle, a defrosting method and a defrosting method in the fuel cell vehicle in addition to the fuel cell vehicle. .

It is explanatory drawing which shows the structure of the fuel cell vehicle carrying a fuel cell system. It is explanatory drawing which shows the flow of the cooling water when a three-way valve is a non-cooperation mode state. It is explanatory drawing which shows the flow of the cooling water when a three-way valve is a cooperation mode state. It is explanatory drawing which shows the structure of an air conditioning duct. It is an example of the control flowchart of one Embodiment in this invention. It is explanatory drawing which shows IV characteristic at the time of normal driving | operating of a fuel cell, and IV characteristic at the time of low efficiency driving | operation. It is a graph explaining the relationship between the cooling water exit water temperature T255 and determination J0 in step S190. It is a graph explaining the relationship between the difference of the cooling water exit water temperature T255 and heater core inlet water temperature T345 in step S200, and determination J1. It is a graph which shows the change of the cooling water exit water temperature T255 and the heater core inlet water temperature T345 after a fuel cell vehicle start.

  FIG. 1 is an explanatory diagram showing the configuration of a fuel cell vehicle 10 equipped with a fuel cell system. The fuel cell vehicle 10 includes a fuel cell 100, a fuel gas circuit 500, an oxidizing gas circuit 600, a fuel cell cooling circuit 200, a heating water circuit 300 (also referred to as an “air conditioning cooling water circuit 300”), And a control unit 400 (Electronic control unit: ECU 400).

  The fuel gas circuit 500 includes a fuel gas tank 510, a fuel gas supply pipe 520, fuel gas exhaust pipes 550 and 560, a fuel gas recirculation pipe 570, an on-off valve 530, a regulator 540, a hydrogen pump 580, and an exhaust valve. 590. The fuel gas tank 510 stores fuel gas. In this embodiment, hydrogen is used as the fuel gas. The fuel gas tank 510 and the fuel cell 100 are connected by a fuel gas supply pipe 520. On the fuel gas supply pipe 520, an open / close valve 530 for turning on / off the supply of the fuel gas from the fuel gas tank 510 and a regulator 540 for adjusting the pressure of the fuel gas supplied to the fuel cell 100 are provided. Yes.

  A fuel gas exhaust pipe 550 for discharging fuel exhaust gas is connected to the fuel cell 100. The fuel gas exhaust pipe 550 is also connected to the fuel gas exhaust pipe 560 and the fuel gas recirculation pipe 570. The fuel gas recirculation pipe 570 is connected to the fuel gas supply pipe 520. A hydrogen pump 580 is disposed on the fuel gas reflux pipe 570. The fuel exhaust gas exhausted to the fuel gas exhaust pipe 550 contains unreacted fuel gas. The unreacted fuel gas is recirculated by the fuel gas recirculation pipe 570 and the hydrogen pump 580, and is again fuel cell. 100.

  The oxidizing gas circuit 600 includes a compressor 610, an oxidizing gas supply pipe 620, an oxidizing gas exhaust pipe 630, a humidifier 640, and a back pressure valve 650. In this embodiment, air is used as the oxidizing gas. The compressor 610 takes in air in the atmosphere and compresses it. The compressor 610 is connected to the fuel cell 100 by an oxidizing gas supply pipe 620. The fuel cell 100 is connected to an oxidizing gas exhaust pipe 630 for discharging oxidizing exhaust gas. Here, the oxidizing gas supply pipe 620 is provided with a humidifier 640 that uses the moisture in the oxidizing gas exhaust pipe 630. As described above, the fuel cell 100 according to the present embodiment generates power by reacting hydrogen and oxygen in the air to generate water. The generated water is discharged from the fuel cell 100 to the oxidizing gas exhaust pipe 630 together with the oxidizing exhaust gas. The humidifier 640 humidifies the oxidizing gas by moving the moisture contained in the oxidizing exhaust gas to the oxidizing gas supplied to the fuel cell 100. For example, the humidifier 640 may include an oxidizing gas channel and an oxidizing exhaust gas channel, and may include a humidifying film between the two channels (not shown). Thereby, it is possible to move the moisture in the oxidation exhaust gas in the oxidation exhaust gas channel to the oxidation gas in the oxidation gas channel via the humidifying film. A back pressure valve 650 is provided in the oxidizing gas exhaust pipe 630. The back pressure valve 650 is used to adjust the pressure of air in the fuel cell 100.

  In the present embodiment, a fuel gas exhaust pipe 560 is connected to the oxidizing gas exhaust pipe 630, and an exhaust valve 590 is provided in the fuel gas exhaust pipe 560. As described above, in this embodiment, the fuel gas exhaust pipe 550 is connected to the fuel gas supply pipe 520 via the fuel gas recirculation pipe 570, and recirculates and reuses the fuel gas (hydrogen). Here, when the fuel cell 100 is operated for a long time, nitrogen that does not contribute to the reaction increases in the fuel exhaust gas. The nitrogen is considered to be that the oxidizing gas (in the air) has permeated the electrolyte membrane (not shown) of the fuel cell 100. When nitrogen increases in the fuel exhaust gas, nitrogen also increases in the fuel gas, and the reactivity of the fuel cell 100 decreases. Therefore, in the present embodiment, when the amount of nitrogen in the fuel exhaust gas increases, the exhaust valve 590 is opened, the fuel exhaust gas is caused to flow through the oxidizing gas exhaust pipe 630, and the nitrogen in the fuel gas is exhausted. At this time, part of the hydrogen also flows into the oxidizing gas exhaust pipe 630. Hydrogen is diluted by the oxidizing exhaust gas in the oxidizing gas exhaust pipe 630 and released to the atmosphere.

  The fuel cell cooling circuit 200 includes a cooling water supply pipe 210, a cooling water discharge pipe 215, a three-way valve 245, a radiator pipe 220, a radiator 230, a bypass pipe 240, and a water pump 225. The cooling water supply pipe 210 is a pipe for supplying cooling water to the fuel cell 100, and a water pump 225 is disposed in the cooling water supply pipe 210. The cooling water discharge pipe 215 is a pipe for discharging cooling water from the fuel cell 100. A downstream portion of the cooling water discharge pipe 215 is connected to the radiator pipe 220 and the bypass pipe 240 via a three-way valve 245. A radiator 230 is provided in the radiator pipe 220. The radiator 230 is provided with a radiator fan 235. The radiator fan 235 sends wind to the radiator 230 and promotes heat dissipation from the radiator 230. The downstream part of the radiator pipe 220 and the downstream part of the bypass pipe 240 are connected to the cooling water supply pipe 210. Temperature sensors 250 and 255 are provided on the upstream side of the water pump 225 of the cooling water supply pipe 210 (downstream part of the radiator pipe 220) and the cooling water discharge pipe 215, respectively.

  The cooling water is supplied to the fuel cell 100 by the water pump 225 through the cooling water supply pipe 210 to cool the fuel cell 100. The cooling water is warmed by recovering heat from the fuel cell 100 and discharged from the cooling water discharge pipe 215. The warmed cooling water is distributed and fed to the radiator pipe 220 and the bypass pipe 240 by the three-way valve 245. The cooling water that has flowed to the radiator pipe 220 is cooled by the radiator 230, but the cooling water that has flowed to the bypass pipe 240 is not cooled. The temperature of the cooling water in the fuel cell cooling circuit 200 is controlled by the distribution ratio of the cooling water to the radiator pipe 220 and the bypass pipe 240 by the three-way valve 245, the outside air temperature, and the air volume from the radiator fan 235. For example, immediately after the fuel cell 100 is started, the temperature of the cooling water in the fuel cell cooling circuit 200 can be rapidly increased by flowing most of the cooling water through the bypass pipe 240.

  The heating water circuit 300 includes a branch pipe 305, a three-way valve 340, a hot water supply pipe 310, a water pump 325, an electric heater 330, a heater core 320, a hot water discharge pipe 315, and a hot water reflux pipe 335. . The branch pipe 305 is connected to the cooling water discharge pipe 215 of the fuel cell cooling circuit 200, and distributes a part of the warmed cooling water discharged from the fuel cell 100 to the heating water circuit 300. The three-way valve 340 controls the inflow of cooling water from the fuel cell cooling circuit 200 to the heating water circuit 300. The electric heater 330 heats the cooling water flowing through the heating water circuit 300. The heater core 320 warms the air using the heat of the cooling water flowing through the heating water circuit 300. The warmed air is sent to the inside of the fuel cell vehicle 10 and used for heating the inside of the vehicle, defrosting, and defrosting. In this specification, defrosting and defrosting are collectively referred to as “defrost”. The hot water discharge pipe 315 returns the waste water from the heater core 320 to the fuel cell cooling circuit 200. The warm water reflux pipe 335 connects between the warm water discharge pipe 315 and the three-way valve 340, and returns the waste water from the heater core 320 to the warm water supply pipe 310. A temperature sensor 345 is disposed between the electric heater 330 and the heater core 320.

  An air conditioner setting unit 410, an outside air temperature sensor 420, and an in-vehicle temperature sensor 430 are connected to the control unit 400. The control unit 400 sets the air conditioner setting unit 410, the outside air temperature, the vehicle interior temperature, the water temperature upstream of the water pump 225 of the hot water supply pipe 310 of the fuel cell cooling circuit 200, and the fuel cell cooling circuit 200. The temperature of the cooling water at the outlet of the fuel cell 100 (hereinafter referred to as “cooling water outlet water temperature T255”) and the temperature of the cooling water at the inlet of the heater core 320 of the heating water circuit 300 (hereinafter referred to as “heater core inlet water temperature T345”). ), The operations of the three-way valves 245 and 340, the water pumps 225 and 325, the radiator fan 235, and the electric heater 330 are controlled. In the present embodiment, the fuel cell 100 is used as a power source for auxiliary equipment such as the water pumps 225 and 325 and the hydrogen pump 580. In the present embodiment, a defroster switch is provided as one of the switches of the air conditioner setting unit 410. The defroster warms the window glass by blowing warm air on the window glass and performs defrosting.

  2 and 3 are explanatory diagrams showing the state of the three-way valve 340 and the flow of cooling water. FIG. 2 shows the flow of cooling water when the three-way valve 340 is in the non-cooperative mode. In the present embodiment, the non-cooperative mode state means that the valve body connected to the branch pipe 305 among the three valve bodies of the three-way valve 340 is closed, and the valve body connected to the hot water supply pipe 310 and the hot water A state in which the valve body connected to the reflux pipe 335 is in an open state. In the non-cooperation mode state, the cooling water flowing through the fuel cell cooling circuit 200 is the cooling water supply pipe 210, the fuel cell 100, the cooling water discharge pipe 215, the three-way valve 245, the radiator pipe 220 (or the bypass pipe 240). ) And the water pump 225 is circulated. The cooling water of the heating water circuit 300 circulates through the hot water supply pipe 310, the water pump 325, the electric heater 330, the heater core 320, the hot water discharge pipe 315, the hot water return pipe 335, and the three-way valve 340. In the non-cooperation mode state, the cooling water does not flow from the cooling water discharge pipe 215 of the fuel cell cooling circuit 200 into the heating water circuit 300, and is cooled from the heating water circuit 300 to the cooling water discharge pipe 215 of the fuel cell cooling circuit 200. Water does not flow out. The fuel cell cooling circuit 200 and the heating water circuit 300 are in an independent state, and the cooling water flowing through the fuel cell cooling circuit 200 and the cooling water flowing through the heating water circuit 300 are not mixed. For example, when the temperature of the fuel cell 100 is low, such as immediately after the start of the fuel cell 100, the temperature of the cooling water in the fuel cell cooling circuit 200 is low. Therefore, the control unit 400 distributes the cooling water in the fuel cell cooling circuit 200 to the heating water circuit 300 and uses it as a heat source for heating, and the cooling water flowing in the fuel cell cooling circuit 200 and the heating water circuit It is more efficient to make the cooling water flowing through 300 independent and to heat only the cooling water flowing through the heating water circuit 300 using the electric heater 330.

  FIG. 3 shows the flow of cooling water when the three-way valve 340 is in the cooperation mode state. The cooperation mode state includes a partial cooperation mode and a complete cooperation mode. 3A shows the partial cooperation mode state, and FIG. 3B shows the complete cooperation mode. In the present embodiment, the partial cooperation mode state refers to any of the valve body connected to the branch pipe 305, the valve body connected to the hot water supply pipe 310, and the valve body connected to the hot water reflux pipe 335. The state which becomes an open state. The complete cooperation mode is a state in which the valve body connected to the branch pipe 305 and the valve body connected to the hot water supply pipe 310 are opened, and the valve body connected to the hot water reflux pipe 335 is closed. say.

  When the three-way valve 340 is in the partial cooperation mode state, a part of the warmed cooling water discharged from the fuel cell 100 is supplied to the hot water supply pipe 310 through the three-way valve 340. Further, a part of the cooling water flowing through the hot water discharge pipe 315 flows into the cooling water discharge pipe 215 of the fuel cell cooling circuit 200 (FIG. 1), and the remaining part passes through the hot water reflux pipe 335 and the three-way valve 340, It is refluxed to the supply pipe 310.

  In the full cooperation mode, the point that the part of the warmed cooling water discharged from the fuel cell 100 is supplied to the hot water supply pipe 310 through the three-way valve 340 is common to the partial cooperation mode. The total amount of the flowing cooling water flows to the cooling water discharge pipe 215 of the fuel cell cooling circuit 200.

  As described above, the control unit 400 controls the movement of cooling water and heat from the fuel cell cooling circuit 200 to the heating water circuit 300 by controlling the mode state of the three-way valve 340. In the cooperation mode, the waste heat of the fuel cell 100 can be used for heating in the vehicle. Note that only one of the partial cooperation mode and the complete cooperation mode may be adopted.

  FIG. 4 is an explanatory diagram showing the configuration of the air conditioning duct 350. The air conditioning duct 350 includes an in-vehicle air intake unit 355, an outside air intake unit 360, an in-vehicle circulation / outside air introduction switching door 365, a heating channel 370, a non-heating channel 375, a partition plate 380, and an air mix door 385. And an in-car blowing part 390. A heater core 320 (FIG. 1) is disposed in the heating channel 370. The in-vehicle circulation / outside air introduction switching door 365 switches between taking in air from the in-vehicle air intake unit 355 or taking in air from the outside air intake unit 360 into the air-conditioning duct 350 according to the setting of the air conditioner setting unit 410 (FIG. 1). . The partition plate 380 separates the heating channel 370 and the non-heating channel 375. The air mix door 385 distributes the taken-in air to the heating channel 370 and the non-heating channel 375. The air distributed to the heating channel 370 is warmed by the heater core 320, but the air distributed to the non-heating channel 375 is not warmed. The air distributed to the heating channel 370 and the non-heating channel 375 is blown into the vehicle from the vehicle blowing unit 390. The vehicle outlet 390 is provided with a lower outlet 392, an upper outlet 394, and a defroster 396. The lower blowing part 392 cools and heats the feet of the occupant, and the upper blowing part 394 cools and heats the occupant's head. Doors 393, 395, and 397 may be provided in the lower blowing portion 392, the upper blowing portion 394, and the defroster 396, respectively. The defroster 396 blows warm air on the window glass. The control unit 400 (FIG. 1) is based on the setting of the air conditioner setting unit 410 (FIG. 1), the temperature in the vehicle, and the temperature of the cooling water in the heating water circuit 300 (heater core inlet water temperature T345). The distribution ratio of the air to the heating flow path 370 and the non-heating flow path 375 in 385 is controlled, the temperature of the air blown out into the vehicle is controlled, and the vehicle interior temperature is controlled. For example, when the heater core inlet water temperature T345 is high, the temperature of the heater core 320 is also high, so the control unit 400 changes the opening of the air mix door 385 to reduce the amount of air flowing through the heating flow path 370. Make sure that the temperature inside the vehicle does not rise too much.

  FIG. 5 is an example of a control flowchart according to an embodiment of the present invention. Note that this flowchart is executed when the temperature is low, such as in winter. In step S100, when the start switch of the fuel cell vehicle 10 is turned on by an occupant (person), the control unit 400 starts the fuel cell 100. At this time, the occupant also turns on the heating switch. In step S110, the control unit 400 normally operates the fuel cell 100, turns on the electric heater 330 of the heating water circuit 300, and sets the mode state of the three-way valve 340 to the non-cooperative mode. Immediately after the start of the fuel cell vehicle 10, both the cooling water in the fuel cell cooling circuit 200 and the cooling water in the heating water circuit 300 are low in temperature. Therefore, it is easier to warm the cooling water in the heating water circuit 300 when the mode state of the three-way valve 340 is set to the non-cooperation mode than to use the cooperation mode.

  In step S120, when it is detected that the defroster 396 has been switched on (defrost request has been made), the control unit 400 proceeds to step S130. In step S130, control unit 400 determines whether or not heater core inlet water temperature T345 (referred to as “heater core inlet water temperature T345”) of heater core 320 is equal to or higher than a predetermined temperature T1. When the heater core inlet water temperature T345 is equal to or higher than the temperature T1, the control unit 400 proceeds to step S170, and when the heater core inlet water temperature T345 is lower than the temperature T1, the control unit 400 proceeds to step S140. To do. The temperature T1 is the temperature of the cooling water in the heating water circuit 300 up to a temperature T3 at which defrosting can be performed without causing the fuel cell 100 to operate with reduced power generation efficiency (referred to as “low efficiency operation”). It is a temperature that can be raised in a short time and is slightly lower than T3. The temperatures T1 and T3 can be obtained experimentally.

  In step S140, the control unit 400 sets the mode state of the three-way valve 340 to the linkage mode, and executes the low efficiency operation of the fuel cell 100. In the cooperation mode, the cooling water in the fuel cell cooling circuit 200 is supplied to the heating water circuit 300. Therefore, when the cooling water in the fuel cell cooling circuit 200 is warmed, the cooling water in the heating water circuit 300 is also warmed. It is done. Next, the low efficiency operation will be described.

  FIG. 6 is an explanatory diagram showing IV characteristics during normal operation and IV characteristics during low-efficiency operation of the fuel cell. The voltage of the fuel cell 100 is highest when the current density (current) is zero (OCV (Open Circuit Voltage)) and decreases as the current density (current) increases. Here, if the current is increased while the supply amounts of the fuel gas (hydrogen) and the oxidizing gas (air) are maintained, the voltage of the fuel cell 100 rapidly decreases and the operating point moves to a point P1 in FIG. . At this time, the fuel cell 100 generates heat, and this heat increases the temperature of the fuel cell 100. The energy generated by the chemical reaction of the fuel cell 100 is divided into electric energy and thermal energy. When the control unit 400 performs control to increase the current while maintaining the supply amount of the oxidizing gas, the ratio of electrical energy decreases and the ratio of thermal energy increases. Since the fuel cell vehicle 10 operates using electric energy, reducing the ratio of electric energy and increasing the ratio of thermal energy lowers the efficiency of the fuel cell vehicle 10 (or the fuel cell 100) (lower efficiency). Is equivalent to) In the present embodiment, an operation in which the ratio of electrical energy is reduced and the ratio of thermal energy is increased as compared with a normal operation is referred to as “low efficiency operation”. In the low-efficiency operation, since the ratio of thermal energy increases, the amount of heat generated by the fuel cell 100 increases, and the temperature of the cooling water in the fuel cell cooling circuit 200 and the temperature of the cooling water in the heating water circuit 300 increases.

  In FIG. 6, the control unit 400 may increase the loss (auxiliary loss) of the hydrogen pump 580 by driving the hydrogen pump 580 more strongly. At this time, as the current consumption of the hydrogen pump 580 increases, the amount of current of the fuel cell 100 also increases, so that the operating point moves from the point P1 to the point P2. In addition, when the hydrogen to be recirculated increases, the energy generated by the chemical reaction of the fuel cell 100 increases, and there is an effect that the thermal energy increases. As a result, the temperature of the fuel cell 100 is increased, and the temperature of the cooling water is increased quickly.

  In FIG. 6, the control unit 400 may drive the water pump 225 more strongly to increase the loss of the water pump 225 (auxiliary machine loss). At this time, as the current consumption of the water pump 225 increases, the amount of current of the fuel cell 100 also increases, so that the operating point moves from the point P2 to the point P3. In addition, since the water pump 225 generates heat when operating, and the water pump 225 itself is in contact with the cooling water, there is an effect that heat generated in the water pump 225 can be directly transferred to the cooling water. As a result, the temperature of the cooling water can be increased quickly. Note that either the hydrogen pump 580 or the water pump 225 may be operated more strongly first. The hydrogen pump 580 and the water pump 225 are examples of auxiliary equipment in the claims.

  In step S150 of FIG. 5, the control unit 400 determines whether or not the heater core inlet water temperature T345 is equal to or higher than a predetermined temperature T2. When the heater core inlet water temperature T345 is equal to or higher than the predetermined temperature T2, the control unit 400 shifts the process to step S160, stops the low-efficiency operation of the fuel cell 100, and shifts to the normal operation. Note that a relatively short time is preferable because low-efficiency driving deteriorates fuel consumption. When frost is attached to the window glass or when it is cloudy, it is difficult to operate the fuel cell vehicle. If the control unit 400 performs defrosting without performing low-efficiency operation, the idling state is maintained for a relatively long time until the defrosting is completed. Considering the fuel efficiency of both, if it is a low-efficiency operation for a short time, the fuel efficiency is not greatly deteriorated compared to the case where the idling state is maintained for a relatively long time, and after the fuel cell vehicle 10 is started, the fuel efficiency is relatively short. Thus, there is an advantage that the defrost is completed and the fuel cell vehicle can be operated.

  In step S170, control unit 400 determines whether heater core inlet water temperature T345 is equal to or higher than a predetermined temperature T3. When the heater core inlet water temperature T345 is equal to or higher than the predetermined temperature T3, the control unit 400 proceeds to step S180, blows warm air from the defroster 396, and executes defrosting of the window glass.

  If the defroster switch is not turned on in step S120, the controller 400 moves the process to step S190. When the defroster switch is not turned on, there is no frost on the window glass and no fogging, and there is little need to rapidly increase the heater core inlet water temperature T345. In step S190, the coolant outlet water temperature T255 is determined.

  FIG. 7 is a graph for explaining the relationship between the coolant outlet water temperature T255 and the determination J0 in step S190. When cooling water outlet water temperature T255 is equal to or higher than a predetermined temperature T4H, control unit 400 sets determination J0 in step S190 to 1. On the other hand, when cooling water outlet water temperature T255 is equal to or lower than a predetermined temperature T4L (T4L <T4H), control unit 400 sets determination J0 in step S190 to 0. When cooling water outlet water temperature T255 is between T4L and T4H, control unit 400 follows the previous determination result. When the previous determination J0 is 1 and the cooling water outlet water temperature T255 is lowered, the determination of 1 is not changed to the determination of 0 unless the cooling water outlet water temperature T255 is lower than T4L. Conversely, when the previous determination J0 is 0 and the cooling water outlet water temperature T255 increases, the determination of 0 does not change to the determination of 1 unless the cooling water outlet water temperature T255 exceeds T4H. By providing hysteresis in this way, frequent fluctuations in the determination result can be suppressed even when the coolant outlet water temperature T255 fluctuates in the vicinity of the determination temperature. In the present embodiment, the values of T4L and T4H are the values of the cooling water outlet water temperature T255, and the cooling water in the fuel cell cooling circuit 200 is converted into the cooling water in the heating water circuit 300 when the cooling water outlet water temperature T255 is reached. This is a determination value for determining whether or not to transmit to the terminal, and may be obtained experimentally. For example, T4L may be set to 30 ° C. and T4H may be set to 35 ° C.

  When the determination J0 is 1 in step S190, the control unit 400 proceeds to step S200, and determines whether or not the difference between the cooling water outlet water temperature T255 and the heater core inlet water temperature T345 is equal to or greater than a predetermined value. to decide.

  FIG. 8 is a graph illustrating the relationship between the difference (hereinafter referred to as “ΔT”) between the cooling water outlet water temperature T255 and the heater core inlet water temperature T345 in Step S200 and the determination J1. Also in FIG. 8, a hysteresis is provided between ΔT and the determination J1. When ΔT is equal to or greater than a predetermined value T5H, the determination J1 is determined to be 1, and when ΔT is less than a predetermined value T5L, the determination J1 is determined to be 0. When ΔT is between T5L and T5H, control unit 400 follows the previous determination result. When the heater core inlet water temperature T345 is lower than the cooling water outlet water temperature T255, ΔT increases. In the case of heating and when ΔT is large, the control unit 400 sets the three-way valve 340 to the cooperation mode, supplies the warm cooling water of the fuel cell cooling circuit 200 to the heating water circuit 300, and the heater core inlet water temperature T345. It is preferable to raise the temperature of as soon as possible. From this viewpoint, T5L and T5H are determined. For example, T5L may be set to −5 ° C. and T5H may be set to 0 ° C. When ΔT is negative, the heater core inlet water temperature T345 is higher in temperature than the cooling water outlet water temperature T255. Therefore, the control part 400 does not need to make the three-way valve 340 into cooperation mode.

  In step S200, when the determination J1 is 1, the control unit 400 proceeds to step S210, sets the three-way valve 340 to the cooperation mode, and supplies the warm cooling water of the fuel cell cooling circuit 200 to the heating water circuit 300. To supply. On the other hand, if determination J0 is 0 in step S190, or if determination J1 is 0 in step S200, control unit 400 proceeds to step S220 and sets three-way valve 340 to the non-cooperative mode.

  FIG. 9 is a graph showing changes in the coolant outlet water temperature T255 and the heater core inlet water temperature T345 after the fuel cell vehicle is started. In the comparative example, only the heater core inlet water temperature T345 is illustrated. In this embodiment, after the defroster switch is turned on, the low-efficiency operation is performed with the three-way valve 340 in the linkage mode. On the other hand, in the comparative example, even when the defroster switch is turned on, the control unit 400 does not set the three-way valve 340 to the cooperation mode and does not execute the low efficiency operation.

  In the present embodiment, the fuel cell 100 is operated with low efficiency, and in the comparative example, the fuel cell 100 is not operated with low efficiency. As a result, the fuel cell 100 generates more heat in the present embodiment than in the comparative example, and the coolant outlet water temperature T255 increases faster in the present embodiment than in the comparative example. In the present embodiment, since the three-way valve 340 is set to the cooperation mode, the heater core inlet water temperature T345 rises in conjunction with the cooling water outlet water temperature T255. On the other hand, in the comparative example, the cooling water of the heating water circuit 300 is heated by the electric heater 330, but the three-way valve 340 is not in the cooperation mode, so that the heat of the fuel cell 100 can be transmitted to the cooling water of the heating water circuit 300. I can't. Therefore, the heater core inlet water temperature T345 rises only slowly. Even if the heat of the fuel cell 100 can be transferred to the cooling water of the heating water circuit 300, since the fuel cell 100 is operated efficiently and generates little heat, the heater core inlet water temperature T345 only rises slowly.

  In both the present embodiment and the comparative example, when the heater core inlet water temperature reaches a predetermined temperature T3, the control unit 400 can perform defrost by blowing warm air from the defroster 396. The time until the heater core inlet water temperature reaches this temperature T3 is earlier in this embodiment than in the comparative example. That is, according to the present embodiment, it is possible to easily generate heat necessary for defrosting. In addition, the time to start defrosting can be shortened.

  In this specification, when the control unit 400 receives a defrost request, the power generation efficiency of the fuel cell 100 is lowered and the fuel cell 100 generates heat compared to the case where the defrost request is not received, and the three-way valve 340 The control in which the heat of the fuel cell 100 is transferred from the fuel cell cooling circuit 200 to the cooling water of the heating water circuit 300 and the defroster 396 executes the defrost is referred to as “first control”. In addition, when the defrost request is not received, the control unit 400 performing the control of the fuel cell 100 in a state where the power generation efficiency of the fuel cell 100 is higher than that of the first control is referred to as “second control”.

  In the present embodiment, the three-way valve 340 is used in the present embodiment. However, instead of the three-way valve 340, another type of valve (for example, an on-off valve) is provided between the fuel cell cooling circuit 200 and the heating water circuit 300. Or a flow control valve) and a configuration without the hot water reflux pipe 335 may be used. Also in this case, the operating state of the on-off valve (flow control valve) is either the non-cooperation mode or the cooperation mode (complete cooperation mode).

  In the present embodiment, the determination in step S130 is performed, but this determination may be omitted. In this case, when determination of step S120 is Yes, the control part 400 transfers a process to step S140.

  In the present embodiment, the determinations in steps S130, S150, and S170 are based on the temperatures T1, T2, and T3, respectively. However, the control unit 400 uses two values for these temperatures, as in steps S190 and S200. In addition, hysteresis may be provided.

  In the present embodiment, it has been described that the flowchart of FIG. 5 is executed at a low temperature such as winter. However, the control unit 400 acquires the outside air temperature, and when the outside air temperature is equal to or lower than a predetermined temperature, the control unit 400 can execute an operation with reduced power generation efficiency of the fuel cell 100, and the outside air temperature is a predetermined temperature. In the case of exceeding the above, even when other conditions are satisfied, the fuel cell 100 may be configured not to perform an operation with a reduced power generation efficiency.

  The embodiments of the present invention have been described above based on some embodiments. However, the embodiments of the present invention described above are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell vehicle 100 ... Fuel cell 200 ... Fuel cell cooling circuit 210 ... Cooling water supply pipe 215 ... Cooling water discharge pipe 220 ... Radiator pipe 225 ... Water pump 230 ... Radiator 235 ... Radiator fan 240 ... Bypass pipe 245 ... Three-way Valve 250 ... Temperature sensor 300 ... Water circuit for heating (cooling water circuit for air conditioning)
305 ... Branch pipe 310 ... Warm water supply pipe 315 ... Warm water discharge pipe 320 ... Heater core 325 ... Water pump 330 ... Electric heater 335 ... Warm water return pipe 340 ... Three-way valve 345 ... Temperature sensor 350 ... Air conditioning duct 355 ... Car air intake section 360 ... Outside air intake portion 365 ... Outside air introduction switching door 370 ... Heating channel 375 ... Non-heating channel 380 ... Partition plate 385 ... Air mix door 390 ... Vehicle outlet 392 ... Lower outlet 393,395,397 ... Door 394 ... Upper outlet 396: Defroster 400: Control unit (ECU)
410: Air conditioner setting unit 420 ... Outside air temperature sensor 430 ... Inside temperature sensor 500 ... Fuel gas circuit 510 ... Fuel gas tank 520 ... Fuel gas supply pipe 530 ... Open / close valve 540 ... Regulator 550 ... Fuel gas exhaust pipe 560 ... Fuel gas exhaust pipe 570 ... fuel gas recirculation pipe 580 ... hydrogen pump 590 ... exhaust valve 600 ... oxidizing gas circuit 610 ... compressor 620 ... oxidizing gas supply pipe 630 ... oxidizing gas exhaust pipe 640 ... humidifier 650 ... back pressure valve T255 ... cooling water outlet water temperature T345 ... heater core Inlet water temperature

Claims (10)

A fuel cell vehicle,
A fuel cell;
A fuel cell cooling circuit for cooling the fuel cell;
A heating water circuit used to heat the interior of the fuel cell vehicle;
A valve for controlling the supply of cooling water from the fuel cell cooling circuit to the heating water circuit;
A defroster for defrosting the window of the fuel cell vehicle using heat of the cooling water of the heating water circuit;
A control unit for controlling the operation of the fuel cell vehicle;
With
The controller is
When the defrost request is received, the power generation efficiency of the fuel cell is lowered compared to the case where the defrost request is not received, the fuel cell is heated, and the valve is opened to transfer the heat to the fuel cell. Moving from the cooling circuit to the cooling water of the heating water circuit, and executing the first control to cause the defroster to execute the defrost,
A fuel cell vehicle that executes second control with higher power generation efficiency of the fuel cell than that of the first control when the defrost request is not received. The fuel cell vehicle according to claim 1, further comprising:
A fuel gas circuit for supplying fuel gas to the fuel cell;
An oxidizing gas circuit for supplying an oxidizing gas to the fuel cell;
With
The control unit decreases the power generation efficiency of the fuel cell and increases the temperature by increasing the current of the fuel cell while maintaining the amounts of the fuel gas and the oxidizing gas supplied to the fuel cell. . The fuel cell vehicle according to claim 2, further comprising:
Equipped with auxiliary equipment,
The said control part is a fuel cell vehicle which raises the loss by the said auxiliary machine and increases the electric current of the said fuel cell, and reduces the electric power generation efficiency of the said fuel cell. The fuel cell vehicle according to claim 3, wherein
The fuel cell cooling circuit includes a water pump for circulating cooling water,
The fuel gas circuit includes a hydrogen pump that circulates the fuel gas discharged from the fuel cell and supplies the fuel gas to the fuel cell.
The said control part is a fuel cell vehicle which reduces the power generation efficiency of the said fuel cell by raising the auxiliary machinery loss of at least one of the said water pump and the said hydrogen pump. The fuel cell vehicle according to any one of claims 1 to 4, further comprising:
With an outside temperature sensor
Further, when the outside air temperature is equal to or lower than a predetermined temperature, the control unit executes the first control in response to the defrost request,
When the outside air temperature exceeds a predetermined temperature, the control unit executes the second control even when there is the defrost request. A cooling circuit for a fuel cell that collects heat from the fuel cell by flowing cooling water, and a heating water circuit that is connected to the cooling circuit for the fuel cell and uses the heat for heating in the air conditioning of the interior of the fuel cell vehicle. A fuel cell comprising: a valve that controls supply of cooling water from the fuel cell cooling circuit to the heating water circuit; and a defroster that defrosts or defrosts using heat of the cooling water of the heating water circuit A vehicle control method comprising:
When the defrost request is received, the fuel cell generates heat by increasing the power generation efficiency of the fuel cell compared to when the defrost request is not received, and the valve is opened to transfer the heat to the fuel cell cooling circuit. To the cooling water of the heating water circuit, to perform the first control to cause the defroster to execute the defrost,
A control method for a fuel cell vehicle, wherein a second control with higher power generation efficiency of the fuel cell than the first control is executed when a request for defrosting or defrosting is not received. The control method for a fuel cell vehicle according to claim 6,
A control method for a fuel cell vehicle, wherein the power generation efficiency of the fuel cell is lowered and the temperature is increased by increasing the current of the fuel cell while maintaining the amount of fuel gas and oxidizing gas supplied to the fuel cell. The method of controlling a fuel cell vehicle according to claim 7,
The fuel cell vehicle includes an auxiliary device, and the power generation efficiency of the fuel cell is reduced by increasing the current of the fuel cell by increasing a loss due to the auxiliary device. The control method of a fuel cell vehicle according to claim 8,
The fuel cell vehicle includes:
A water pump for circulating cooling water in the fuel cell cooling circuit;
A hydrogen pump that circulates the fuel gas discharged from the fuel cell and supplies the fuel gas to the fuel cell, and
A control method for a fuel cell vehicle, wherein power generation efficiency of the fuel cell is reduced by increasing an auxiliary machine loss of at least one of the water pump and the hydrogen pump. In the control method of the fuel cell vehicle according to any one of claims 6 to 9,
Further, when the outside air temperature is equal to or lower than a predetermined temperature, the first control is executed in response to the defrost request,
A control method for a fuel cell vehicle, wherein when the outside air temperature exceeds a predetermined temperature, the second control is executed even when there is a defrost request.

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