Vehicle control system

Abstract

The present invention provides a vehicle control device that can suppress the deterioration of energy consumption rate associated with the operation of the water heater, even when the FC water circuit and the heating water circuit are switched from an independent circuit state to an integrated circuit state. [Solution] Provided that the first circulation channel 10 equipped with the first water pump 13 and the second circulation channel 20 equipped with the second water pump 23 are in communication, the second control constant map for controlling the second water pump 23 is set to a coordinated control constant map that changes the control amount of the second water pump 23 according to the control amount of the first water pump 13. This makes it possible to suppress changes in the cooling water flow rate in the second circulation channel 20, suppress an increase in the power consumption of the water heating heater 24, and suppress the deterioration of the energy consumption rate.

Description

Technical Field

[0001] The present invention relates to a vehicle control device.

Background Art

[0002] Conventionally, in a fuel cell electric vehicle (FCEV) that runs using the power generated by a fuel cell stack, there is an air conditioner configured such that the waste heat of the fuel cell stack can be used for heating the vehicle interior.

[0003] Specifically, in this type of air conditioner, by supplying the cooling water heated by the waste heat of the fuel cell stack to a heater core (a heater core for heating the air for air conditioning), the heating effect in the vehicle interior is improved. Also, when the temperature of the cooling water supplied to the heater core is lower than the target water temperature at the inlet of the heater core, it is common to heat the cooling water using a water heater (electric heater) or the like.

[0004] As a configuration of a general cooling water circulation circuit in this type of air conditioner, as disclosed in Patent Document 1, the FC water circuit and the heating water circuit are connected via a flow path switching valve such as a three-way valve. That is, it is possible to switch between a state where the FC water circuit and the heating water circuit are communicated (a state where the cooling water heated by the waste heat of the fuel cell stack is supplied to the heater core; hereinafter referred to as the circuit cooperation state) and a state where the flow path switching valve is separated from the FC water circuit (hereinafter referred to as the circuit independent state). Also, each of the FC water circuit and the heating water circuit is equipped with a water pump, and each water pump is independently controlled.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] Incidentally, when the flow path of the cooling water is switched from a standalone circuit state to a linked circuit state by the flow path switching valve, some of the cooling water that was previously flowing through the FC water circuit will flow into the heating water circuit, which may cause a significant change (increase) in the cooling water flow rate in the heating water circuit.

[0007] Generally, water heaters control power consumption according to the difference between the target water temperature and the current water temperature. As mentioned above, if the cooling water flow rate in the heating water circuit changes significantly, the power required to raise the cooling water to the target temperature increases, which tends to increase power consumption and raise concerns about a deterioration in energy efficiency.

[0008] The present invention has been made in view of the above, and its objective is to provide a vehicle control device that can suppress the deterioration of energy consumption rate associated with the operation of the heater (the aforementioned water heating heater) even when the FC water circuit and the heating water circuit are switched from a circuit-only state to a circuit-linked state. [Means for solving the problem]

[0009] The present invention provides a vehicle control device comprising: a first circulation path comprising a first water pump whose discharge amount of coolant changes by control using a first control constant map, and a radiator that dissipates heat from the coolant; a second circulation path comprising a second water pump whose discharge amount of coolant changes by control using a second control constant map, a heater core that heats the air supplied to the passenger compartment by heat exchange with the coolant, and a heater that heats the coolant introduced into the heater core; and a flow path switching valve that can switch the communication state between the first circulation path and the second circulation path. The vehicle control device is characterized in that, on the condition that the first circulation path and the second circulation path are in communication by the flow path switching valve, the second control constant map that controls the second water pump is set to a linked control constant map that changes the control amount of the second water pump according to the control amount of the first water pump.

[0010] When the first and second circulation channels are connected, the cooling water flow rate in the second circulation channel may change significantly. However, by setting a coordinated control constant map that changes the control amount of the second water pump according to the control amount of the first water pump, the change in the cooling water flow rate in the second circulation channel can be suppressed. This prevents the power consumption of the heater required to raise the cooling water to the target temperature from increasing, thus preventing a deterioration in energy consumption efficiency. [Effects of the Invention]

[0011] In this invention, provided that a first circulation channel equipped with a first water pump and a second circulation channel equipped with a second water pump are in communication, the second control constant map for controlling the second water pump is set to a coordinated control constant map that changes the control amount of the second water pump according to the control amount of the first water pump. This makes it possible to suppress changes in the cooling water flow rate in the second circulation channel, suppress an increase in heater power consumption, and suppress a deterioration in energy consumption rate. [Brief explanation of the drawing]

[0012] [Figure 1] This diagram schematically shows the cooling water circulation circuit of the air conditioning system and fuel cell stack cooling system according to the embodiment, where Figure 1(a) shows the circuit in a standalone state and Figure 1(b) shows the circuit in a linked state. [Figure 2] Figure 2(a) shows a block diagram of the schematic configuration of the control system for the cooling water circulation circuit, Figure 2(b) shows the individual control constant map used when the circuit is in isolation, and Figure 2(c) shows the combined control constant map used when the circuits are in combination. [Figure 3] This is a flowchart illustrating the procedure for switching control constant maps. [Modes for carrying out the invention]

[0013] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0014] - Configuration of the cooling water circulation circuit - Figure 1 is a schematic diagram showing the cooling water circulation circuit 1 of the air conditioning system and fuel cell stack cooling system according to this embodiment, where Figure 1(a) shows the circuit in a standalone state (described later), and Figure 1(b) shows the circuit in a linked state (described later). Figure 2(a) is a block diagram showing the schematic configuration of the control system of the cooling water circulation circuit 1.

[0015] The cooling water circulation circuit 1 is installed in a fuel cell vehicle (not shown) and, as shown in Figure 1, has a configuration comprising a first circulation channel (also called the FC water circuit) 10 and a second circulation channel (also called the heating water circuit) 20.

[0016] The first circulation channel 10 is configured such that the fuel cell stack 11, radiator 12, first water pump 13, rotary valve 14, and intercooler 15 are connected by cooling water pipes 16 to 19 to enable the circulation of cooling water. The fuel cell stack 11 and the radiator 12 are connected by the first pipe 16 and the second pipe 17. The first water pump 13 is installed in the first pipe 16 and circulates the cooling water in the first circulation channel 10. The rotary valve 14 is installed in the second pipe 17 and is connected to a bypass pipe 18 that bypasses the radiator 12. The intercooler 15 is installed in the third pipe 19 that connects the first pipe 16 and the second pipe 17. In addition, a first water temperature sensor 10a is installed on the inlet side of the fuel cell stack 11 (downstream end of the first pipe 16) to detect the inlet water temperature of the fuel cell stack 11. A second water temperature sensor 10b for detecting the outlet water temperature of the fuel cell stack 11 is installed at the outlet side of the fuel cell stack 11 (the upstream end of the second pipe 17).

[0017] The configurations and functions of the fuel cell stack 11, radiator 12, first water pump 13, and intercooler 15 are well known, so their description is omitted here.

[0018] The rotary valve 14 is a solenoid valve that can switch between the case where the cooling water circulating in the first circulation passage 10 passes through the radiator 12 and the case where it does not pass through (bypasses) the radiator 12. When the inlet water temperature of the fuel cell stack 11 detected by the first water temperature sensor 10a exceeds the inlet target water temperature required for cooling the fuel cell stack 11, the opening and closing of the rotary valve 14 is controlled by the ECU 100 so that the cooling water flows through the radiator 12. On the other hand, when the inlet water temperature of the fuel cell stack 11 detected by the first water temperature sensor 10a is below the inlet target water temperature, the rotary valve 14 is controlled by the ECU 100 so that the cooling water flows through the intercooler 15 and the fuel cell stack 11 without passing through the radiator 12.

[0019] The second circulation passage 20 is configured such that a heater core 21 that heats the air for air conditioning by heat exchange between the air for air conditioning and the cooling water, a flow path switching valve 22, a second water pump 23, and a water heater (the heater referred to in the present invention) 24 that heats the cooling water supplied to the heater core 21 are connected by cooling water pipes 25 to 27 so that the cooling water can circulate. The heater core 21 and the flow path switching valve 22 are connected by a fourth pipe 25. The heater core 21 and the water heater 24 are connected by a fifth pipe 26. The flow path switching valve 22 and the water heater 24 are connected by a sixth pipe 27. The second water pump 23 is disposed in the sixth pipe 27 and circulates the cooling water in the second circulation passage 20. A third water temperature sensor 20a for detecting the inlet water temperature of the heater core 21 is disposed at the inlet side of the heater core 21 (the downstream end of the fifth pipe 26). A fourth water temperature sensor 20b for detecting the outlet water temperature of the heater core 21 is disposed at the outlet side of the heater core 21 (the upstream end of the fourth pipe 25).

[0020] Since the configurations and functions of the heater core 21, the second water pump 23, and the water heater 24 are well-known, the description thereof is omitted here.

[0021] Between the flow path switching valve 22 and the second pipe 17, they are connected by an introduction pipe 31 and a lead-out pipe 32. The introduction pipe 31 is a pipe for introducing a part of the cooling water flowing through the second pipe 17 into the second circulation flow path 20 via the flow path switching valve 22. The lead-out pipe 32 is a pipe for leading out a part of the cooling water flowing through the second circulation flow path 20 into the first circulation flow path 10 via the flow path switching valve 22. The flow path switching valve 22 switches the connection state between the first circulation flow path 10 and the second circulation flow path 20, thereby putting the first circulation flow path 10 and the second circulation flow path 20 in a communicating state (a state where the cooling water heated by the waste heat of the fuel cell stack 11 is supplied to the heater core 21) (see Fig. 1(b)), and a circuit single state (see Fig. 1(a)) where the second circulation flow path 20 is separated from the first circulation flow path 10 and the cooling water is circulated in each of the circulation flow paths 10, 20.

[0022] In the circuit cooperation state, as shown in Fig. 1(b), the flow path switching valve 22 communicates the introduction pipe 31 with the sixth pipe 27 and also communicates the lead-out pipe 32 with the fourth pipe 25. As a result, the cooling water introduced from the first circulation flow path 10 into the second circulation flow path 20 will flow through the second water pump 23, the water heating heater 24, and the heater core 21 in sequence and then be returned to the first circulation flow path 10.

[0023] Specifically, when there is no or low heating requirement in the vehicle interior, the flow path switching valve 22 is switched by the ECU 100 to separate the second circulation flow path 20 from the first circulation flow path 10. On the other hand, when the heating requirement in the vehicle interior is high, the flow path switching valve 22 is switched by the ECU 100 to communicate the first circulation flow path 10 and the second circulation flow path 20.

[0024] When the waste heat from the fuel cell stack 11 is used for heating, the water heater 24 is controlled by the ECU 100 to heat the cooling water discharged from the outlet of the fuel cell stack 11 and flowing into the second circulation channel 20, raising the temperature of the cooling water to a level (the target water temperature at the inlet of the heater core 21) that can be used as a heat source for heating the vehicle interior, if the outlet water temperature of the fuel cell stack 11 detected by the second water temperature sensor 10b is lower than the target water temperature at the inlet of the heater core 21. The cooling water heated by the water heater 24 flows through the heater core 21, and the heater core 21 heats the air supplied to the vehicle interior. The water heater 24 may also be controlled according to the inlet water temperature of the heater core 21 detected by the third water temperature sensor 20a.

[0025] As described above, the water temperature information detected by each water temperature sensor 10a, 10b, 20a, and 20b is input to the ECU 100 as a water temperature signal. The ECU 100 also controls the discharge amount of cooling water from each water pump 13 and 23, controls the switching of the rotary valve 14 and the flow path switching valve 22, and controls the output of the water heating heater 24.

[0026] As described above, the ECU 100 controls the switching of the flow path switching valve 22 and the rotary valve 14, as well as the output of the water heating heater 24, based on the water temperature detected by each water temperature sensor 10a, 10b, 20a, and 20b, and the target water temperature at the inlet of the fuel cell stack 11 and the heater core 21. The ECU 100 also controls the amount of cooling water discharged from each water pump 13 and 23. This control of the amount of cooling water discharged from each water pump 13 and 23 is performed according to control constants set by a control constant map pre-stored in the ECU 100. Specifically, the ECU 100 stores a first control constant map used for controlling the first water pump 13 and a second control constant map used for controlling the second water pump 23, and the amount of cooling water discharged from each water pump 13 and 23 is controlled using the control constants defined in these control constant maps. The control of the second water pump 23 by the second control constant map will be described later.

[0027] In conventional technology, when the cooling water flow path is switched from a single circuit state to a linked circuit state by a flow path switching valve, some of the cooling water that was previously flowing through the first circulation path (FC water circuit) flows into the second circulation path (heating water circuit), which can cause a significant change (large increase) in the cooling water flow rate in the heating water circuit. In this case, the power consumption of the water heater required to raise the cooling water to the target temperature tends to increase, potentially leading to a situation where a deterioration in energy consumption efficiency is a concern.

[0028] In view of this point, this embodiment is configured such that when the flow path of the cooling water is switched from a circuit-only state to a circuit-linked state by the flow path switching valve 22, the second control constant map for controlling the second water pump 23 is set to a linked control constant map that changes the control amount of the second water pump 23 according to the control amount of the first water pump 13, based on this condition. The configuration of the ECU 100 for realizing this operation will be described below.

[0029] As shown in Figure 2(a), the ECU 100 includes a memory unit 110, a switching control unit 120, and a control constant map setting unit 130 as functional units realized by a control program.

[0030] The memory unit 110 stores multiple control constant maps used to control the second water pump 23. Specifically, it stores an independent control constant map that sets the control amount of the second water pump 23 regardless of the control amount of the first water pump 13 when the circuit is in an independent state, and a linked control constant map that sets the control amount of the second water pump 23 according to the control amount of the first water pump 13 when the circuit is linked.

[0031] Figure 2(b) shows the individual control constant map. As shown in Figure 2(b), the individual control constant map pre-defines that even if the duty cycle (controlled amount) of the first water pump 13 changes, the duty cycle of the second water pump 23 will remain constant.

[0032] Figure 2(c) shows the linked control constant map. As shown in Figure 2(c), the linked control constant map pre-defines that as the duty cycle of the first water pump 13 increases, the duty cycle of the second water pump 23 decreases. Therefore, in the linked circuit state, even if the duty cycle of the first water pump 13 increases, leading to an increase in the amount of cooling water circulating in the first circulation channel 10, and consequently an increase in the amount of cooling water flowing into the second circulation channel 20, the decrease in the duty cycle of the second water pump 23 suppresses an increase in the amount of circulation in the second circulation channel 20. This ensures that the amount of circulation in the second circulation channel 20 remains approximately constant regardless of the change in the duty cycle of the first water pump 13.

[0033] The switching control unit 120 determines whether it is necessary to switch the cooling water flow path between a standalone circuit state and a linked circuit state, and if it determines that a switch is necessary, it transmits a switching command signal to the flow path switching valve 22. For example, in a situation where the circuit is in a standalone state, if a heating request is made in the vehicle cabin, and the outlet water temperature of the fuel cell stack 11 detected by the second water temperature sensor 10b is above a predetermined temperature, a switching command signal to the linked circuit state is transmitted to the flow path switching valve 22 in order to utilize the waste heat from the fuel cell stack 11 for heating. This switching command signal is also output to the control constant map setting unit 130.

[0034] The control constant map setting unit 130 changes the second control constant map used to control the amount of cooling water discharged from the second water pump 23, provided that it has received the switching command signal. Specifically, it reads the linked control constant map from the storage unit 110 and changes the second control constant map used to control the amount of cooling water discharged from the second water pump 23 from a standalone control constant map to a linked control constant map. In other words, provided that the cooling water flow path is switched from a standalone circuit state to a linked circuit state, the second control constant map used to control the amount of cooling water discharged from the second water pump 23 is switched from a standalone control constant map that maintains a constant duty cycle of the second water pump 23 regardless of changes in the duty cycle of the first water pump 13 to a linked control constant map that decreases the duty cycle of the second water pump 23 as the duty cycle of the first water pump 13 increases. Furthermore, when the cooling water flow path is switched (returned) from a linked circuit state to an independent circuit state, the second control constant map used to control the amount of cooling water discharged from the second water pump 23 is switched from a linked control constant map to an independent control constant map.

[0035] -Control constant map switching process- Next, the control constant map switching process in the cooling water circulation circuit 1 configured as described above will be explained. Figure 3 is a flowchart showing the procedure for the control constant map switching process. This flowchart is executed repeatedly when the vehicle's start switch is ON.

[0036] First, with the vehicle's start switch turned ON and the coolant flow path in a single-circuit state, the second control constant map used to control the coolant discharge amount in the second water pump 23 is in a single-circuit control constant map state. In step ST1, it is determined whether the coolant flow path has been switched from a single-circuit state to a linked-circuit state. This determination is made by the switching control unit 120 as described above. If the coolant flow path remains in a single-circuit state and the determination in step ST1 is NO, the usage state of the single-circuit control constant map is maintained and the process returns as is.

[0037] On the other hand, if the cooling water flow path is switched from a single circuit state to a linked circuit state, and a YES determination is made in step ST1, the process moves to step ST2, where the second control constant map used to control the amount of cooling water discharged from the second water pump 23 is switched from a single control constant map to a linked control constant map. This operation is performed by the control constant map setting unit 130. As a result, the control transitions to one in which the duty cycle of the second water pump 23 is decreased as the duty cycle of the first water pump 13 increases.

[0038] After the second control constant map is switched to the linked control constant map in this way, the process moves to step ST3 to determine whether the cooling water flow path has been switched (returned) from the linked circuit state to the independent circuit state. If the cooling water flow path remains in the linked circuit state and the result in step ST3 is NO, the process returns to the previous state.

[0039] On the other hand, if the cooling water flow path is switched from a circuit-linked state to a circuit-independent state, and a YES determination is made in step ST3, the process moves to step ST4, where the second control constant map used to control the amount of cooling water discharged from the second water pump 23 is switched from a linked control constant map to an independent control constant map. This operation is also performed by the control constant map setting unit 130. As a result, the control returns to maintaining a constant duty cycle for the second water pump 23 regardless of changes in the duty cycle of the first water pump 13. This operation is repeated.

[0040] -Effects of the embodiment- As described above, in this embodiment, the second control constant map for controlling the second water pump 23 is set to a coordinated control constant map that changes the duty cycle of the second water pump 23 according to the duty cycle of the first water pump 13, provided that the flow path switching valve 22 switches the communication state between the first circulation flow path 10 and the second circulation flow path 20 from an independent control constant map to a coordinated control constant map. This makes it possible to suppress changes in the cooling water flow rate in the second circulation flow path 20, suppress an increase in the power consumption of the water heating heater 24, and suppress the deterioration of the energy consumption rate.

[0041] -Other Embodiments- Furthermore, the present invention is not limited to the embodiments described above, and all modifications and applications are possible within the scope of the claims and equivalents thereof.

[0042] In the present invention, the coordinated control constant map was set so that the duty cycle of the second water pump 23 was inversely proportional to the duty cycle of the first water pump 13 over the entire control range of the second water pump 23. The present invention is not limited to this, and the duty cycle of the second water pump 23 may be set inversely proportional to the duty cycle of the first water pump 13 over a portion of the control range of the second water pump 23. [Industrial applicability]

[0043] The present invention is applicable to the control of the water pump in the cooling water circulation circuit of a control device for a fuel cell vehicle. [Explanation of Symbols]

[0044] 10…First circulation channel 12…Radiator 13…First water pump 20...Second circulation channel 21...Heater core 22...Flow channel switching valve 23...Second water pump 24...Water heating heater (heater) 100...ECU 130...Control constant map setting unit

Claims

[Claim 1] A first water pump whose discharge rate of cooling water is changed by control using a first control constant map, and a first circulation path equipped with a radiator that dissipates heat from the cooling water, A second water pump whose cooling water discharge rate changes by control using a second control constant map, a heater core that heats the air supplied to the passenger compartment by heat exchange with the cooling water, and a second circulation channel equipped with a heater that heats the cooling water introduced into the heater core, A vehicle control device comprising a flow path switching valve capable of switching the communication state between the first circulation flow path and the second circulation flow path, A vehicle control device characterized by comprising a control constant map setting unit that sets the second control constant map for controlling the second water pump to a linked control constant map that changes the control amount of the second water pump according to the control amount of the first water pump, provided that the first circulation path and the second circulation path are in communication by the flow path switching valve.

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