JP5772660B2 - Air conditioning control method and air conditioning control system - Google Patents

Description

  The present invention relates to an air conditioning control method and an air conditioning control system. More specifically, the present invention relates to an improvement in air conditioning control in a system including a fuel cell.

  In a system including a fuel cell, the exhaust heat of the fuel cell is used by controlling a valve connecting the cooling circuit of the fuel cell and the cooling circuit for air conditioning.

  For example, in a system that includes a fuel cell cooling circuit and an air conditioning circuit, and these two are connected by a switching valve or can be configured as independent circuits, the detection result by the coolant outlet temperature sensor of the fuel cell Accordingly, both circuits are connected if they are equal to or higher than the allowable connection temperature, and are operated as independent circuits if they are lower than the allowable connection temperature (see, for example, Patent Document 1). In such a system, control is performed so as to bypass the heater core when high-temperature cooling water flows through the heater core during cooling.

JP 2010-282808 A

  However, as described above, when high-temperature cooling water flows through the heater core during cooling, control is performed so that the heater core is bypassed. Since it rises, the compressor electric energy for cooling an evaporator becomes large. In short, the conventional control technology is to open the three-way valve and supply the exhaust heat of the fuel cell to the air conditioning side if the fuel cell outlet water temperature is higher than a predetermined temperature. The optimal fuel saving control has not been achieved.

  Therefore, an object of the present invention is to provide an air-conditioning control method and an air-conditioning control system that enable fuel-saving control that further reduces the amount of electric power.

  In order to solve this problem, the present inventors have studied. Conventionally, when the outlet temperature of the fuel cell is equal to or higher than a predetermined temperature (above the allowable connection temperature), the three-way valve is always opened, the fuel cell circuit and the air conditioning circuit are connected, and the fuel cell cooling water is allowed to flow into the air conditioning circuit. Has been done. In such a conventional technique, it is intended to reduce the power consumption of the electric heater by utilizing the exhaust heat of the fuel cell during heating. However, the prior art does not consider the adverse effects during cooling. That is, during cooling, when high-temperature cooling water flows into the heater core, the air cooled by the evaporator bypasses the heater core, but passes through the vicinity of the heater core, whereby the air-conditioning blower temperature rises and the blowing temperature also rises. Since the evaporator needs to be further cooled by the temperature rise, the power consumption of the compressor increases. The inventor who has repeatedly studied focusing on such points has come to obtain new knowledge that leads to the solution of such problems.

  The present invention based on such knowledge is a fuel cell system including a fuel cell, a heater core that exchanges heat between the cooling water of the fuel cell and the air, and an air-conditioning system that controls the amount of air flowing into the heater core. An air conditioning control method for adjusting a temperature of a temperature control target region by controlling a valve connecting a cooling circuit for a fuel cell and a cooling circuit for air conditioning in a moving body including an air damper for air mix. When the air damper is closed without warming up, the outlet water temperature of the fuel cell is compared with the outlet water temperature of the heater core, and when the outlet water temperature of the heater core is high, the cooling water flows into the heater core from the fuel cell. When the outlet water temperature is low, the fuel cell cooling circuit and the air conditioning cooling circuit are controlled independently.

  An air conditioning control system according to the present invention includes a fuel cell system including a fuel cell, a heater core that exchanges heat between cooling water and the like of the fuel cell, and air, and an air conditioning that controls the amount of air flowing into the heater core. Air conditioning control that adjusts the temperature of the temperature control target region by controlling a valve that connects a fuel cell cooling circuit and an air conditioning cooling circuit with a control means in a moving body including an air damper for air mixing The control means compares the fuel cell outlet water temperature and the heater core outlet water temperature when the air damper is closed without warming up. If the heater core outlet water temperature is high, the control means transfers the fuel cell to the heater core. When cooling water is introduced and the outlet water temperature of the heater core is low, the fuel cell cooling circuit and the air conditioning cooling circuit are controlled independently.

  For example, when considering air conditioning control in a vehicle HVAC (hybrid air conditioning system equipped with an air conditioning cycle, a heater core, and a control ECU (control unit)), air passing through the blower is cooled (or dehumidified) by an evaporator. Then, it is reheated by the heater core and blown into the passenger compartment. Further, the amount of air flowing into the heater core is controlled by the opening of the air mix damper, and the blowing temperature is controlled. For example, if the outside air temperature is high, or if the sunlight is strong and the air conditioning load is high, the air mix damper is completely closed to block the air flow to the heater core so that cold air is blown into the passenger compartment. ing. In such a case where the outside air temperature is high, even if the air mix damper is completely closed, the heater core is not completely insulated in the HVAC, so the surrounding air is warmed and the duct is formed by heat conduction. Loosening and raising the temperature of the air-conditioning air blow.

  In this regard, in the present invention, when it is not necessary to reheat the air-conditioning air blow by heating, the energy loss due to heat received from the heater core is minimized by flowing cooling water having a low water temperature through the heater core. Reduce the power consumption of the air compressor.

  The present invention is suitable for indoor air conditioning of a fuel cell vehicle equipped with a fuel cell, for example.

  According to the present invention, it is possible to perform fuel saving control that further reduces the amount of electric power.

It is a figure which shows schematically a part of structure of the fuel cell system in one Embodiment of this invention. It is a figure which shows the structural example of the duct part for an air conditioning which comprises an air-conditioning control system. It is a figure which shows an example of the fuel cell vehicle FCHV carrying a fuel cell system. It is a flowchart which shows an example of the air-conditioning control method.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  1 and 2 schematically show a part of the configuration of the fuel cell system 1 in the present embodiment, and FIG. 3 shows an example of a fuel cell vehicle FCHV in which the fuel cell system 1 is mounted. The fuel cell vehicle FCHV travels by driving the traction motor 115 with the electric power generated by the fuel cell 2. As shown in the drawing, the fuel cell vehicle FCHV of the present embodiment includes a high-voltage DC / DC converter 61, a battery 62, a traction inverter 63, a body 118 of the vehicle, a transmission 119, and hydrogen as fuel, in addition to the fuel cell 2. A filling port 121, a brake pedal 124, a hydrogen tank 200, and the like are provided (see FIG. 3).

  The fuel cell system 1 of this embodiment includes a fuel cell 2, an oxidizing gas piping system (not shown) that supplies air (oxygen) as an oxidizing gas to the fuel cell 2, and hydrogen as a fuel gas to the fuel cell 2. A fuel gas piping system (not shown) to be supplied, a refrigerant piping system 5 for supplying a refrigerant (cooling medium) to the fuel cell 2 to cool the fuel cell 2, and a power system (not shown) for charging / discharging system power And a control unit (control ECU) 7 for overall control of the entire system. In FIG. 1, among these, the refrigerant piping system 5 is mainly illustrated.

  The fuel cell 2 is formed of a solid polymer electrolyte type, for example, and has a stack structure in which a large number of single cells are stacked. A single cell of the fuel cell 2 has an air electrode on one surface of an electrolyte made of an ion exchange membrane, a fuel electrode on the other surface, and a pair of separators so as to sandwich the air electrode and the fuel electrode from both sides. have. The fuel gas is supplied to the fuel gas flow path of one separator and the oxidizing gas is supplied to the oxidizing gas flow path of the other separator, and the fuel cell 2 generates electric power by this gas supply.

The refrigerant piping system (cooling system) 5 cools the refrigerant flow path 41 communicating with the cooling flow path in the fuel cell 2, the cooling pump 42 provided in the refrigerant flow path 41, and the refrigerant discharged from the fuel cell 2. A radiator 43 that bypasses the radiator 43, a release valve 45 that sets the flow of cooling water to the radiator 43 and the bypass passage 44, and an air conditioning cooling water circuit 46 that branches from the refrigerant passage And a three-way valve 47, a pump 48, and a water heater 49 provided in the middle of the air conditioning cooling water circuit 46 (see FIG. 1). The air conditioning cooling water circuit 46 is connected to the heater core 81 of the air conditioning control system 8. In position of the coolant channel 41, the fuel cell exit value the water temperature sensor 51 for detecting the fuel cell outlet temperature T _FC is disposed.

  The three-way valve 47 opens and closes to connect the air conditioning cooling water circuit 46 and the fuel cell 2 (the refrigerant piping system 5), or alternatively, the air conditioning cooling water circuit 46 and the fuel cell 2 (the refrigerant piping system thereof). 5) is separated. Specifically, when the three-way valve 47 is opened, the air conditioning cooling water circuit 46 and the fuel cell 2 are connected to each other, and a part of the cooling water discharged from the outlet of the fuel cell 2 is discharged from the refrigerant channel 41. It flows into the cooling water circuit 46 for air conditioning, flows through the three-way valve 47, the pump 48, the water heater 49, the heater core 81, and returns to the refrigerant flow path 41 (see the hatched arrows in FIG. 1). On the other hand, when the three-way valve 47 is closed, the air conditioning control system 8 and the fuel cell 2 (the refrigerant piping system 5 thereof) are disconnected, and the cooling water (refrigerant) circulates in each. That is, the cooling water that has exited from the outlet of the fuel cell 2 circulates through the refrigerant channel 41 and returns to the fuel cell 2. Further, in the air conditioning cooling water circuit 46, the cooling water that has passed through the heater core 81 returns to the three-way valve 47 through the bypass channel 50, and flows again toward the heater core 81 through the air conditioning cooling water circuit 46. (See white arrow in FIG. 1).

  The control unit 7 is configured as a microcomputer including a CPU, a ROM, and a RAM inside. The CPU executes a desired calculation according to the control program, and performs various processes and controls such as the above-described three-way valve open / close control. The ROM stores control programs and control data processed by the CPU. The RAM is mainly used as various work areas for control processing. The control unit 7 inputs detection signals from various pressure sensors, temperature sensors, and outside air temperature sensors used for the gas system (oxidizing gas piping system, fuel gas piping system) and the refrigerant piping system 5, and controls each component. Output a signal.

The air conditioning control system 8 is a system for air conditioning the interior of the fuel cell vehicle FCHV. In addition to the heater core 81 described above, the air mix damper 82, the evaporator 83, the air conditioning blower 84, the air conditioning duct 85, the capacitor 86, the electric motor A compressor 87, a heater core temperature sensor 89, a heater core outlet water temperature sensor 90, and the like are provided (see FIGS. 1 and 2). The heater core 81, the air mix damper 82, the evaporator 83, and the air conditioning blower 84 are disposed in the air conditioning duct 85 (see FIG. 2 and the like). The evaporator 83, the condenser 86, and the electric compressor 87 are each connected to an air conditioning refrigerant flow path 88. Heater core temperature sensor 89 for detecting the heater core temperature T _W is, for example, installed at a predetermined position on the cooling pipe 46. Further, a heater core outlet water temperature sensor 90 for detecting the heater core outlet temperature T _HC have also been installed at a predetermined position on the cooling pipe 46. The air mix damper 82 is opened and closed by an actuator (not shown) (see FIG. 1).

  Next, an air conditioning control method in the fuel cell vehicle FCHV equipped with the fuel cell system 1 will be described (see FIG. 4). In the present embodiment, when air-conditioning air is not required to be reheated (reheated) by heating when air-conditioning the passenger compartment of the fuel cell FCHV, heat receiving from the heater core 81 is performed by flowing low-temperature cooling water through the heater core 81. The energy loss due to the air pressure is minimized, and the power consumption of the electric compressor (air conditioning air compressor) 87 is reduced.

Specific control, first, a state where the air mixing damper 82 for air conditioning is fully closed (YES in step SP1 of FIG. 4), the fuel cell outlet temperature T _FC and the heater core outlet water temperature T relationship of the _HC is T _FC if <T _HC (YES in step SP2), to open the three-way valve 47 (step SP3), the cooling water to flow from the fuel cell 2 side to the heater core 81 side (see FIG. 4). In such a case, the exhaust heat of the fuel cell 2 can be used in the air conditioning control system 8 (the air conditioning duct 85).

On the other hand, if the T _FC> T _HC relationship of the fuel cell outlet temperature T _FC and the heater core outlet water temperature T _HC (NO in step SP2), determines that it is when it is not necessary to reheat the conditioned air blowing by heating, The three-way valve 47 is closed (step SP4). In such a case, the air conditioning control system 8 and the refrigerant piping system 5 of the fuel cell 2 are disconnected, and cooling water (refrigerant) circulates in each of them. Cooling water in a state not receiving exhaust heat) flows.

  The above-described air conditioning control method will be described in further detail below.

The air-conditioning blowout target temperature TAO (see FIGS. 1 and 2) is determined from environmental conditions such as the vehicle interior temperature, the outside air temperature, the amount of solar radiation, and the set temperature of the driver. Control unit 7, outlet temperature from the air-conditioning duct 85 is the evaporator temperature T _E to be the target temperature TAO, controls the opening of the heater core temperature T _W and the air mixing damper 82. For example, when the cooling capacity is necessary as in the summer, the air mix damper 82 is closed and control is performed so that the airflow from the air is not applied to the heater core 81 (through the heater core 81). Due to the structure, there is a certain amount of heat received from the heater core 81. At this time, the required cooling capacity Q is
Q = A × (TAO + ΔT _W −T suction)
It becomes.

Here, ΔT _W is the temperature rise of the blast due to the amount of heat received from the heater core 81. A is a value determined from the air volume of the air-conditioning blower 84. Further, the T suction is the temperature of the blast before being passed through the evaporator 83 after being sucked into the air conditioning duct 85.

As can be seen from this equation, if ΔT _W is lowered, the cooling capacity Q can be reduced, and the consumption capacity of the electric compressor 87 can also be reduced. ΔT _W varies depending on the temperature of the cooling water flowing through the heater core 81, and ΔT _W decreases as the heater core temperature T _W decreases. Therefore, in the present embodiment, a large thermal load in the cabin, when the air mixing damper 82 is closed, comparing the heater core outlet temperature T _HC and the fuel cell stack exit temperature T _FC, the temperature cooling water is low The three-way valve 47 is controlled so as to flow into the heater core 81. For example, when the water temperature on the air conditioning side during cooling in summer (cooling water temperature of the air conditioning control system 8) is low, the high-temperature cooling water from the fuel cell 2 is supplied to the water channel (air conditioning cooling water circuit 46) on the air conditioning control system 8 side. If the cooling water on the adjustment control system 8 side having a low water temperature is returned to the heater core 81 again, the amount of heat dissipated from the heater core 81 to the air-conditioning fan is reduced, and the electric energy of the electric compressor 87 can be reduced. it can.

  Conventionally, if the fuel cell outlet temperature is equal to or higher than a predetermined temperature (connection permission temperature), the three-way valve is opened and the exhaust heat of the fuel cell is supplied to the air conditioning side. The optimal fuel saving control is not considered. In other words, the technology that connects the fuel cell circuit and the air conditioning circuit so that the fuel cell cooling water always flows into the air conditioning circuit is intended to reduce the power consumption of the electric heater using the exhaust heat of the fuel cell during heating. However, there are not enough considerations regarding adverse effects during cooling. That is, during cooling, when high-temperature cooling water flows into the heater core, the air cooled by the evaporator bypasses the heater core, but by passing through the vicinity of the heater core, the air-conditioning blower temperature rises and the blowing temperature also rises. Since the evaporator needs to be further cooled by the temperature rise, the power consumption of the compressor increases. In this respect, the conventional air conditioning control technology is not sufficient.

  On the other hand, in this embodiment, if it is not necessary to reheat the air-conditioning airflow by heating, low-temperature cooling water is allowed to flow through the heater core 81 so that high-temperature cooling water does not flow into the heater core 781. According to this, energy loss due to heat received from the heater core 81 can be minimized, and the power consumption of the electric compressor 87 can be reduced.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the example in which the present invention is applied to the fuel cell vehicle FCHV equipped with the fuel cell system 1 has been described. However, this is only a preferred example, and other various mobile bodies other than the fuel cell vehicle ( For example, the present invention can be applied to a ship or an airplane.

  In the above-described embodiment, the present invention is applied to a system that uses the exhaust heat of the fuel cell 2, but a system (or various mobile objects including the system) in which a heat source other than the fuel cell (for example, a prime mover) is used as a heat source. It is also possible to apply the present invention to the above.

  The present invention is suitable for application to an air conditioning control technique in a moving body equipped with a fuel cell system or the like.

DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Fuel cell, 7 ... Control part (control means), 8 ... Air conditioning control system, 41 ... Refrigerant flow path (cooling circuit of fuel cell), 46 ... Cooling piping (cooling circuit for air conditioning) , 47 ... Three-way valve (valve), 81 ... Heater core, 82 ... Air mix damper (air damper), FCHV ... Fuel cell vehicle (moving body)

Claims (3)

A fuel cell system including a fuel cell; a heater core that exchanges heat between the cooling water of the fuel cell and the air; and an air damper for an air-conditioning air mix that controls the amount of air flowing into the heater core. In a moving body, an air conditioning control method for adjusting a temperature of a temperature control target region by controlling a valve connecting a cooling circuit for the fuel cell and a cooling circuit for air conditioning,
If before Symbol air damper is closed, comparing the outlet water temperature of the heater core outlet temperature of the fuel cell, when the outlet water temperature of the heater core is high allowed to flow into the cooling water to the heater core from the fuel cell, the heater core An air conditioning control method for independently controlling the fuel cell cooling circuit and the air conditioning cooling circuit when the outlet water temperature of the fuel cell is low. A fuel cell system including a fuel cell; a heater core that exchanges heat between the cooling water of the fuel cell and the air; and an air damper for an air-conditioning air mix that controls the amount of air flowing into the heater core. In the moving body, an air conditioning control system that adjusts the temperature of the temperature control target region by controlling a valve that connects the cooling circuit of the fuel cell and the cooling circuit for air conditioning by a control unit,
Wherein when prior SL air damper is closed, comparing the outlet water temperature of the outlet water temperature of the fuel cell heater core, if the outlet water temperature of the heater core is high cooling water to the heater core from the fuel cell An air conditioning control system that controls the cooling circuit for the fuel cell and the cooling circuit for air conditioning independently when the outlet water temperature of the heater core is low.   The air conditioning control system according to claim 2, which is intended for indoor air conditioning of a fuel cell vehicle equipped with the fuel cell.

Images