Control method for hybrid vehicles, and control device for hybrid vehicles

Abstract

To provide a control method of a hybrid vehicle by which a requested heating output can be obtained by a heating device for heating a vehicle cabin by using heat of an engine even when a battery is fully charged, and a control device of a hybrid vehicle.SOLUTION: A hybrid vehicle 100 comprises: a battery 10; an electric motor 16; a power generation system 12 which includes an engine 18 and a power generator 19 and generates power to be stored in the battery 10; and a heating device (heater 21) for heating a vehicle cabin by heat of a coolant (cooling water) for cooling the engine 18. In the hybrid vehicle 100, when rotation of the engine 18 and the power generator 19 is stopped, the power generator 19 is heated by discharging power of the battery 10 to the power generator 19 while maintaining the torque generated by the power generator 19 at zero. Then, with the heat produced at the power generator 19, the temperature of the coolant (engine water temperature TW) is maintained at a prescribed target temperature.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a control method for a hybrid vehicle and a control device for a hybrid vehicle. [Background technology]

[0002] Patent Document 1 discloses a hybrid vehicle in which, when there is a surplus of usable power including regenerative power, the surplus power is consumed by electric heaters such as an engine water temperature heater or a heating heater water temperature heater. Patent Document 2 discloses a motor control device that warms up a drive motor by supplying alternating positive and negative currents to the drive motor while setting the shaft current command value corresponding to the torque component of the drive motor to zero. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 6485494 [Patent Document 2] Patent No. 6131715 [Overview of the project] [Problems that the invention aims to solve]

[0004] Vehicles equipped with an engine typically have a heater that uses the heat generated by the engine's operation (hereinafter referred to as "engine heat") to heat the passenger compartment.

[0005] In hybrid vehicles, such as parallel hybrid vehicles, where the engine's power can be used to drive the vehicle, the engine can continue to run when heating is required, even if the battery is fully charged or nearly fully charged (see, for example, Patent Document 1). Therefore, in parallel hybrid vehicles, even if the battery is fully charged or nearly fully charged, the required heating output can be obtained from the heater by running the engine.

[0006] On the other hand, in series hybrid vehicles, where the power generated by the engine is used exclusively for electricity generation, the engine must be stopped in principle when the battery is fully charged or nearly fully charged. Therefore, in series hybrid vehicles, even if there is a demand for heating, the engine cools down when the battery is fully charged or nearly fully charged. As a result, the required heating output may not be obtained by the aforementioned heater.

[0007] Furthermore, even if the engine is run to use its heat for heating, when the battery is fully charged or nearly fully charged, the engine will maintain rotation with virtually no load, producing torque equivalent to friction. In other words, the engine cannot be run with sufficient power to produce the heat corresponding to the required heating output, and therefore the required heating output cannot be obtained by the aforementioned heater.

[0008] Furthermore, it is conceivable to repeatedly consume battery power by letting the engine run idle (so-called motoring) and then running the engine (generating power), but even in this case, the required heating output may not be obtained by the aforementioned heater.

[0009] As shown in Figure 8, a conventional cooling system 200 in a series hybrid vehicle consists of, for example, a first cooling circuit 201 and a second cooling circuit 202 that are independent of each other. The first cooling circuit 201 is a cooling circuit that cools the drive motor 211 and the generator 212 that constitute the power generation system, and a pump P1 circulates coolant to the motor 211 and the generator 212. When the coolant reaches a predetermined high temperature, a thermostat Th1 circulates the coolant to the radiator 213 to cool it down. On the other hand, the second cooling circuit 202 is a cooling circuit that cools the engine 214 that constitutes the power generation system, and a heater 215 that uses the heat generated by the engine 214 to heat the passenger compartment is connected to it. In the second cooling circuit 202, a pump P2 circulates coolant to the engine 214 and the heater 215. When the coolant reaches a predetermined high temperature, a thermostat Th2 circulates the coolant to the radiator 213 to cool it down. In a conventional cooling system 200 configured in this way, when motoring and power generation are repeated, heat is intermittently supplied to the heater 215 in accordance with the timing of when the engine 214 is operated by power generation, and during periods of motoring, the cooling water is cooled naturally, for example. As a result, even if motoring and power generation are repeated, the required heating output may not be obtained.

[0010] In addition, as described in Patent Document 1, providing an additional electric heater presents problems in terms of vehicle packaging and cost.

[0011] Therefore, the present invention aims to provide a control method for a hybrid vehicle and a control device for a hybrid vehicle, which enable the heating output to be obtained by a heater that uses engine heat to heat the passenger compartment, even when the battery is fully charged or nearly fully charged. [Means for solving the problem]

[0012] One aspect of the present invention is a control method for a hybrid vehicle comprising a battery for storing electricity, an electric motor that generates driving force for the wheels using the electricity from the battery, a power generation system including an engine and a generator that generates electricity to be stored in the battery, and a heater that heats the passenger compartment using the heat from a refrigerant that cools the engine. In this control method for a hybrid vehicle, when the engine and generator are stopped rotating, the generator is heated by discharging electricity from the battery to the generator while maintaining the torque generated by the generator at zero. When the battery charge level is above a predetermined threshold and the heater is running, The heat generated by the generator maintains the refrigerant's temperature at a predetermined target temperature. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a control method for a hybrid vehicle and a control device for a hybrid vehicle that can obtain the required heating output by a heater that uses engine heat to heat the passenger compartment, even when the battery is fully charged or nearly fully charged. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is an explanatory diagram showing the schematic configuration of a hybrid vehicle. [Figure 2] Figure 2 is an explanatory diagram showing the configuration of the cooling system installed in a hybrid vehicle. [Figure 3] Figure 3 is a block diagram showing the controller configuration. [Figure 4] Figure 4 is a block diagram showing the configuration of the generator controller. [Figure 5] Figure 5 is a flowchart showing the operation of the heating discharge control. [Figure 6] Figure 6 is a time chart that schematically shows the changes in engine water temperature and other parameters over time. [Figure 7] Figure 7 is an explanatory diagram showing the schematic configuration of a modified hybrid vehicle. [Figure 8]Figure 8 is an explanatory diagram showing the configuration of a conventional cooling system found in a series hybrid vehicle. [Modes for carrying out the invention]

[0015] Embodiments of the present invention will be described below with reference to the drawings.

[0016] Figure 1 is an explanatory diagram showing the schematic configuration of the hybrid vehicle 100. As shown in Figure 1, the hybrid vehicle 100 is a so-called series hybrid vehicle and comprises a battery 10, a vehicle drive system 11, a power generation system 12, and a controller 13.

[0017] Battery 10 stores power to drive the hybrid vehicle 100. Battery 10 is rechargeable. Battery 10 is charged by power generated by the power generation system 12. Battery 10 is also charged by regenerative power input from the vehicle drive system 11. Battery 10 supplies DC power to the vehicle drive system 11. Battery 10 can also supply DC power to the power generation system 12. In this embodiment, battery 10 supplies DC power to the vehicle drive system 11. Output voltage of battery 10 (hereinafter referred to as battery voltage V) dc Parameters representing the state of the battery 10, such as the State of Charge (SOC) of the battery 10, can be obtained as needed by detection using sensors (not shown) or by calculation. SOC is a parameter that represents the charge state (charge rate) of the battery 10.

[0018] The vehicle drive system 11 generates driving force in the drive wheels 14 using power supplied from the battery 10 and / or the generator 19. In this embodiment, the vehicle drive system 11 generates driving force in the wheels 14 using power supplied from the battery 10. In addition to the wheels 14, the vehicle drive system 11 includes, for example, a first inverter 15 and an electric motor 16.

[0019] The first inverter 15 converts the DC power from the battery 10 into AC power and inputs it to the motor 16. Also, when the motor 16 is rotated by the wheels 14, the inverter 15 converts the regenerative AC power input from the motor 16 into DC power and inputs it to the battery 10.

[0020] The electric motor 16 is the power source for the vehicle drive system 11 (hybrid vehicle 100). In other words, the electric motor 16 is a drive motor that drives the hybrid vehicle 100 using the power from the battery 10. The power from the electric motor 16 is transmitted to the wheels 14 via the gearbox 17, etc., generating the driving force of the hybrid vehicle 100. The electric motor 16 is, for example, a three-phase AC synchronous motor.

[0021] The power generation system 12 is a system that generates electricity to be stored in the battery 10. The power generation system 12 includes an engine 18, a generator 19, and a second inverter 20, etc.

[0022] The engine 18 is the power source for the power generation system 12 and is an internal combustion engine driven by, for example, gasoline or other fuel. The power generated by the engine 18 is input to the generator 19. The engine 18 may also be run idle (so-called motoring) by the generator 19. For example, the engine 18 may be motored when consuming power to reduce the State of Charge (SOC) of the battery 10.

[0023] Parameters indicating the operating state of the engine 18 can be obtained as needed by detection using sensors (not shown) or by calculation. For example, the engine speed of the engine 18 (hereinafter referred to as engine speed N) is one such parameter. E (hereinafter referred to as engine torque τ) E (hereinafter referred to as engine oil temperature T) oil (hereinafter referred to as engine water temperature T) and the temperature of the coolant and other refrigerants that cool the engine 18. W (and so on.)

[0024] The generator 19 is a power generation motor that generates electricity by the power of the engine 18. The generator 19 is, for example, a three-phase AC synchronous motor. The AC power generated by the generator 19 is input to the second inverter 20.

[0025] In particular, in the present embodiment, in order to heat the passenger compartment of the hybrid vehicle 100, when the power generation system 12 is not generating electricity, that is, when the engine 18 and the generator 19 have stopped rotating, the power of the battery 10 may be supplied (discharged) to the generator 19. In this case, the torque generated in the generator 19 is maintained at zero. That is, the power of the battery 10 is discharged to the generator 19 so that the generator 19 does not rotate and no torque is generated. As a result, the generator 19 is heated. Then, using the heat generated in the generator 19, the passenger compartment of the hybrid vehicle 100 is heated, or the state in which the passenger compartment of the hybrid vehicle 100 can be heated is continued. The discharge control to the generator 19 for this heating (hereinafter referred to as heating discharge control) will be described in detail later.

[0026] Parameters indicating the operating state etc. of the generator 19 can be appropriately acquired as needed by detecting using a sensor etc. not shown in the drawings, or by calculation. Parameters indicating the operating state etc. of the generator 19 are, for example, the rotational speed of the generator 19 (hereinafter referred to as generator rotational speed N G ), torque (hereinafter referred to as generator torque τ G ), the temperature of the rotor etc. provided in the generator 19 (hereinafter referred to as generator temperature T G ), and the d-axis current I d and q-axis current I q (hereinafter referred to as dq-axis current I d , I q ), etc. The generator temperature T G is represented by, for example, the temperature of the rotor (not shown) provided in the generator 19. In the present embodiment, for simplicity, the engine rotational speed N E and the generator rotational speed N G are assumed to be substantially equal.

[0027] The second inverter 20 converts the AC power input from the generator 19 into DC power and inputs it to the battery 10. This charges the battery 10. When the engine 18 is motoring, the second inverter 20 converts the DC power from the battery 10 into AC power and supplies it to the generator 19, thereby driving the generator 19 and generating torque to rotate the engine 18. Also, when heating discharge control is performed, the second inverter 20 converts the DC power from the battery 10 into AC power and supplies it to the generator 19. However, the AC power supplied by the second inverter 20 to the generator 19 when heating discharge control is performed does not drive the generator 19. That is, in heating discharge control, the second inverter 20 supplies AC power to the generator 19 that maintains the stopped state of the generator 19 (and engine 18). Note that the temperature of the second inverter 20 (hereinafter referred to as the second inverter temperature T) INV2 The temperature of ( ) can be detected by a sensor (not shown) and acquired as needed.

[0028] The controller 13 is a control device that comprehensively controls each part of the hybrid vehicle 100. The controller 13 is composed of one or more computers and is programmed to control each part of the hybrid vehicle 100 at a predetermined control cycle. One or more programs for controlling each part of the hybrid vehicle 100 are stored in a solid-state drive, memory, or other storage medium (not shown).

[0029] The controller 13 acquires parameters (vehicle parameters) indicating the operating status of each part constituting the hybrid vehicle 100, using sensors or calculations as needed. For example, the controller 13 acquires the battery voltage V for the battery 10. dc And obtains the State of Charge (SOC). The controller 13 determines the engine oil temperature T with respect to the engine 18. oil , and engine water temperature T W The controller 13 obtains the generator rotation speed N with respect to the generator 19. G , and the dq axis current Id ,I q The controller 13 also obtains the second inverter temperature T. INV2 The temperature of each component of the hybrid vehicle 100 is acquired. The specific configuration of the controller 13 will be described in detail later.

[0030] In addition to the above, the hybrid vehicle 100 is equipped with a heater 21 for heating the passenger compartment. The heater 21 is, in principle, a heater that uses the heat generated by the engine 18 to heat the passenger compartment of the hybrid vehicle 100. The heater 21 is installed, for example, in the circulation path of the coolant or other refrigerant (including air or other gases) that cools the engine 18, and heats the passenger compartment with the heat contained in the coolant or other refrigerant.

[0031] Figure 2 is an explanatory diagram showing the configuration of the cooling system 30 provided in the hybrid vehicle 100. As shown in Figure 2, the hybrid vehicle 100 includes a cooling system 30 which includes a first cooling circuit 31 and a connecting circuit 33. The arrows in Figure 2 indicate the flow direction of the cooling water or other refrigerant (hereinafter simply referred to as cooling water).

[0032] The first cooling circuit 31 is a refrigerant flow path (waterway) that cools the electric motor 16 and the generator 19 by circulating cooling water. The first cooling circuit 31 includes a basic flow path 34, a short-circuit flow path 35, and a bypass flow path 36. The first cooling circuit 31 also includes a pump P1, a thermostat Th1, and a valve V 1a ,V 1b It is equipped with.

[0033] The main flow path 34 is a water channel that circulates the cooling water that has flowed through the electric motor 16, then through the generator 19, and then back through to the electric motor 16. The short-circuit flow path 35 is a water channel that circulates the cooling water that has flowed through the electric motor 16 back through to the electric motor 16 without going through the generator 19. A portion of the short-circuit flow path 35 is shared with the main flow path 34.

[0034] The bypass channel 36 is a waterway that circulates the cooling water that has flowed through the electric motor 16, or the electric motor 16 and the generator 19, to the radiator 37. The bypass channel 36 is connected to the main channel 34 and the short-circuit channel 35.

[0035] Pump P1 is located in the common section of the main flow path 34 and the short-circuit flow path 35, and circulates the cooling water of the first cooling circuit 31. In this embodiment, pump P1 is located between the thermostat Th1 and the electric motor 16.

[0036] Thermostat Th1 is installed at the connection point between the bypass passage 36 and the main passage 34 and the short-circuit passage 35, and connects or disconnects the radiator 37 depending on the temperature of the coolant flowing through the first cooling circuit 31. Specifically, when the coolant in the first cooling circuit 31 reaches a predetermined temperature (high temperature), thermostat Th1 connects the radiator 37 to the main passage 34, the short-circuit passage 35, or the main passage 34 and the short-circuit passage 35. As a result, the coolant flowing through the first cooling circuit 31 is cooled by the radiator 37 and maintained at or below the predetermined temperature. Consequently, the temperature of the electric motor 16, the generator 19, or the electric motor 16 and the generator 19 is maintained at or below the predetermined temperature.

[0037] Valve V 1a ,V 1b These are installed upstream and downstream of the generator 19, respectively. Valve V 1a ,V 1b When it is open, cooling water circulates through the main flow path 34 and the short-circuit flow path 35. Meanwhile, valve V 1a ,V 1b When the gate is closed, the generator 19 is disconnected from the first cooling circuit 31, and the cooling water circulates through the short-circuit passage 35.

[0038] The second cooling circuit 32 is a refrigerant passage (water channel) that cools the engine 18 by circulating coolant. The coolant circulating in the second cooling circuit 32 is the same as the coolant circulating in the first cooling circuit 31. The second cooling circuit 32 includes a main passage 38 and a bypass passage 39. The second cooling circuit 32 also includes a pump P2, a thermostat Th2, and a temperature sensor S.TW It is equipped with.

[0039] The main flow path 38 is a water channel that circulates the coolant that has flowed through the engine 18 to the heater 21, and then back to the engine 18. The bypass flow path 39 is a water channel that circulates the coolant that has flowed through the engine 18 to the radiator 37, and is connected to the main flow path 38.

[0040] Pump P2 is located in the basic flow path 38 and circulates the cooling water of the second cooling circuit 32. In this embodiment, pump P2 is located between the thermostat Th2 and the engine 18.

[0041] Thermostat Th2 is installed at the connection point between the bypass passage 39 and the main passage 38, and connects or disconnects the radiator 37 depending on the temperature of the coolant flowing through the second cooling circuit 32. Specifically, when the coolant in the second cooling circuit 32 reaches a predetermined temperature (high temperature), thermostat Th2 connects the radiator 37 to the main passage 38. As a result, the coolant that has flowed through the engine 18 is cooled by the radiator 37 to below the predetermined temperature, and then flows back into the engine 18. Consequently, the temperature of the engine 18 is maintained below the predetermined temperature. Note that the predetermined temperature at which thermostat Th1 operates and the predetermined temperature at which thermostat Th2 operates may be the same or different. In this embodiment, the predetermined temperature at which thermostat Th2 operates is higher than the predetermined temperature at which thermostat Th1 operates.

[0042] Temperature sensor S TW This is the temperature of the coolant that has circulated through the engine 18, i.e., the engine water temperature T. W To measure this, the temperature sensor S TW It is located in the basic flow path 38, downstream of the engine 18 and upstream of the heater 21 (and radiator 37). The temperature of the coolant that has flowed through the engine 18 substantially represents the temperature of the engine 18.

[0043] The connecting circuit 33 is a refrigerant flow path (water channel) that connects the first cooling circuit 31 and the second cooling circuit 32. More specifically, the connecting circuit 33 connects the basic flow path 34 of the first cooling circuit 31 and the basic flow path 38 of the second cooling circuit 32. In this embodiment, the connecting circuit 33 connects the downstream of the engine 18 and the upstream of the generator 19, thereby allowing the cooling water that has flowed through the engine 18 to flow to the generator 19. Furthermore, the connecting circuit 33 connects the downstream of the generator 19 and the upstream of the heater 21, thereby allowing the cooling water that has flowed through the generator 19 to flow back to the engine 18 via the heater 21. Therefore, the connecting circuit 33 expands the basic flow path 38 of the second cooling circuit 32, allowing the cooling water of the second cooling circuit 32 to flow not only to the engine 18 but also to the generator 19. As a result, the cooling water that has absorbed the heat generated in the generator 19 flows through the heater 21. In other words, even when the engine 18 is stopped, for example, when the cooling water of the second cooling circuit 32 is extended by the connecting circuit 33 to flow to the generator 19, the heater 21 can heat the passenger compartment with the heat generated by the generator 19.

[0044] The connecting circuit 33 is valve V 2a ,V 2b Equipped with valve V 2a ,V 2b These are provided in the connecting circuit 33, upstream and downstream of the generator 19, respectively. Valve V 2a ,V 2b When the valve V is closed, the second cooling circuit 32 forms a refrigerant flow path independent of the first cooling circuit 31. 2a ,V 2b When the gate is open, the second cooling circuit 32 is connected to the first cooling circuit 31.

[0045] In this embodiment, as shown in Table 1 below, the cooling system 30 includes the valve V of the first cooling circuit 31. 1a ,V 1b The opening and closing of the valve V of the connecting circuit 33. 2a ,V 2b The system can be switched between the first and second flow path modes by combining the opening and closing of the device.

[0046] [Table 1]

[0047] The first flow path mode is valve V 1a ,V 1b The valve V is set to the open state, and 2a ,V 2b This is a mode in which the gate is closed. In the first flow path mode, the first cooling circuit 31 and the second cooling circuit 32 become independent refrigerant flow paths. In this case, the cooling water of the first cooling circuit 31 circulates through the basic flow path 34 and the short-circuit flow path 35 to cool the electric motor 16 and the generator 19. The cooling water of the second cooling circuit 32 circulates through the basic flow path 38. That is, the second cooling circuit 32 cools the engine 18, and the cooling water that has absorbed the heat generated by the engine 18 flows to the heater 21. The first flow path mode is used, for example, when the power generation system 12 can generate electricity as needed.

[0048] The second flow path mode is valve V 1a ,V 1b Set valve V to the closed state, and 2a ,V 2b This is a mode in which the gate is in an open state. In the second flow path mode, a part of the first cooling circuit 31 and the second cooling circuit 32 are connected by a connecting circuit 33. In this case, the cooling water of the first cooling circuit 31 circulates through the short-circuit flow path 35 and cools the electric motor 16. The cooling water of the second cooling circuit 32 circulates through the engine 18, the generator 19, and the heater 21. That is, the cooling water of the second cooling circuit 32 cools the engine 18 and the generator 19, and the cooling water that has the heat generated by the engine 18 and the generator 19 flows to the heater 21. The second flow path mode is used, for example, when the power generation system 12 cannot generate power as needed, that is, when the engine 18 and the generator 19 must be stopped.

[0049] Figure 3 is a block diagram showing the configuration of the controller 13. As shown in Figure 3, the controller 13 includes a drive controller 41, a battery controller 42, an engine controller 43, a generator controller 44, and a temperature control unit 45, etc.

[0050] The drive controller 41 controls the operation of the vehicle drive system 11. Specifically, the drive controller 41 controls the driving force that the electric motor 16 generates on the wheels 14 and the regenerative braking force generated by the electric motor 16, based on the vehicle speed of the hybrid vehicle 100, the amount of accelerator operation, and the rotational speed of the electric motor 16.

[0051] The battery controller 42 obtains the State of Charge (SOC), temperature, internal resistance, input power, and output power of the battery 10 by measuring or calculating using sensors (not shown).

[0052] The engine controller 43, together with the generator controller 44, constitutes a power generation system controller that controls the power generation system 12. The engine controller 43 controls the operation of the engine 18 when the power generation system 12 is generating electricity. Specifically, the engine controller 43 controls the engine torque τ so that the power generation system 12 can achieve the required amount of power generated. E The engine 18 is driven so that (not shown) the engine torque is predetermined. Whether or not power generation is necessary, and if power generation is necessary, the amount of power required from the power generation system 12, is determined, for example, based on the State of Charge (SOC) of the battery 10.

[0053] Specifically, the State of Computer Occupation (SOC) of battery 10 exceeds a predetermined lower threshold S. L When the State of Charge (SOC) of the battery 10 falls below (for example, approximately 50%), or is expected to fall below that level, the power generation system 12 is required to generate electricity. For this reason, the engine controller 43 drives the engine 18 to output a predetermined engine torque. Meanwhile, when the State of Charge (SOC) of the battery 10 falls below a predetermined upper threshold S, H When the value exceeds approximately 80% (for example), or is expected to exceed that value, power generation by the power generation system 12 is stopped. Also, when the power generation system 12 is stopped, that stopped state is maintained. The predetermined engine torque is determined, for example, so that the BSFC (Net Fuel Consumption Rate) is minimized.

[0054] The generator controller 44 controls the operation of the generator 19. In particular, in this embodiment, the generator controller 44 comprises a power generation control unit 46 and a heating discharge control unit 47.

[0055] The power generation control unit 46 controls the operation of the generator 19 when the power generation system 12 is generating power. Specifically, the power generation control unit 46 controls the generator rotation speed N G The generator 19 is controlled so that it reaches a predetermined rotational speed. The predetermined rotational speed is determined, for example, so that the BSFC is minimized.

[0056] The heating discharge control unit 47 controls the operation of the generator 19 as needed when the power generation system 12 is not generating power. Specifically, the heating discharge control unit 47 performs heating discharge control to heat the generator 19 by discharging power from the battery 10 to the generator 19. Heating discharge control is performed when the generator 19 (and engine 18) is stopped, that is, when the power generation system 12 is not generating power. Furthermore, heating discharge control is performed in order to maintain the stopped state of the generator 19. The stopped state of the generator 19 means that the generator 19 is not rotating and the generator torque τ G This refers to a state in which no such thing occurs.

[0057] More specifically, the heating discharge control performed by the heating discharge control unit 47 controls the q-axis current I of the generator 19. q (q-axis current command value I q * ) is kept at virtually zero, and the d-axis current I of the generator 19 d (d-axis current command value I d * This is achieved by discharge control (hereinafter referred to as d-axis discharge) that effectively makes the value non-zero.

[0058] The d-axis and q-axis constitute a rotating coordinate system that rotates with the rotor. The d-axis represents the direction of the magnetic flux formed by the rotor's magnetic poles, and the q-axis represents the direction 90 degrees ahead in phase from the d-axis. That is, the q-axis current I q The generator torque τ GThis contributes to the generation of [something]. On the other hand, the d-axis current I d This is the current that generates magnetic flux in the stator, and the generator torque τ G It does not contribute to the generation of [the specified variable]. Therefore, as described above, the heating discharge control unit 47 controls the q-axis current I q By keeping it virtually zero, the generator 19 does not rotate, and the generator torque τ G Maintain a state in which no such event occurs. Furthermore, the heating discharge control unit 47 controls the d-axis current I d Set to a non-zero value, and selectively select the d-axis current I d By flowing this current, hysteresis loss and eddy current loss (so-called iron loss) are generated in the stator. Therefore, the generator torque τ is affected by the d-axis discharge. G While maintaining this, the generator 19 is heated.

[0059] The heating discharge control unit 47 controls the heating discharge by the d-axis discharge described above, for example, by an upper threshold S predetermined by the State of Charge (SOC) of the battery 10. H Execute when the above is true. Upper threshold S H This is an indicator that the battery 10 is effectively fully charged or close to fully charged (hereinafter simply referred to as "fully charged") for control purposes.

[0060] In this embodiment, at least the SOC of the battery 10 is above the upper threshold S. H In the above conditions, and when the heater 21 is operating, the heating discharge control unit 47 performs heating discharge control using d-axis discharge. This is one of the scenarios in which heating at the requested output may not be sustained. That is, when the SOC is fully charged, the power generation system 12 cannot operate, and therefore the engine 18 does not generate heat. For this reason, the cooling water heated by the engine 18 cannot be circulated to the heater 21. As a result, even if the heater 21 is operating and heating of the passenger compartment is required, the heater 21 may not be able to provide the heating output required.

[0061] In addition to the above, the heating discharge control unit 47 can acquire information related to the gradient of the road surface on which the hybrid vehicle 100 travels (hereinafter simply referred to as the road surface gradient), and can perform heating discharge control by d-axis discharge based on the information related to the road surface gradient.

[0062] In this embodiment, the heating discharge control unit 47 determines whether the road surface on which the hybrid vehicle 100 is traveling is on a downhill slope. At a minimum, if the road surface on which the hybrid vehicle 100 is traveling is on a downhill slope, and the State of Charge (SOC) of the battery 10 is above the upper threshold S H When the above conditions are met, the heating discharge control unit 47 performs heating discharge control using d-axis discharge. This is one of the scenarios in which heating at the requested output may not be sustained. In other words, when the hybrid vehicle 100 is traveling downhill, it is necessary to activate the regenerative braking force from the electric motor 16 in order to avoid wasting energy. For this reason, on a downhill slope, the State of Charge (SOC) of the battery 10 needs to have enough capacity to accept regenerative power. Consequently, when the SOC becomes fully charged or nearly fully charged while traveling downhill, the power generation system 12 cannot be operated. As a result, the heater 21 may not be able to provide the required heating output. The information related to the road surface gradient includes, for example, estimated values ​​of disturbances acting on the hybrid vehicle 100, information related to the driving route pre-registered in the car navigation system, or information related to the accelerator operation amount (accelerator opening) and vehicle speed.

[0063] The heating discharge control unit 47 controls the engine water temperature T W A predetermined temperature T W1 When the value is smaller than a given temperature T, heating discharge control can be performed using d-axis discharge. W1 This is predetermined by conformity through experiments or simulations, etc. In this embodiment, in order to respond to heating requests that occur at any given time, the engine water temperature T is used as a general rule. W The predetermined temperature T W1 Maintained above. Engine water temperature T W at a predetermined temperature T W1When it becomes lower than [a certain value], the temperature of the cooling water in the second cooling circuit 32 in the heater 21 may decrease to a temperature that cannot respond to a heating demand at an arbitrary timing. Therefore, when the engine water temperature T W becomes lower than a predetermined temperature T W1 , the heating discharge control unit 47 executes heating discharge control by d-axis discharge. Therefore, if the cooling system 30 is in the second flow path mode, the temperature of the cooling water flowing through the heater 21 is maintained at a temperature that can respond to a heating demand at an arbitrary timing by the heat generated in the generator 19.

[0064] The temperature management unit 45 acquires the temperatures of each part constituting the hybrid vehicle 100 and determines whether an abnormality has occurred in each part by comparing with a predetermined value (threshold value) determined for each part. For example, the temperature management unit 45 acquires the generator temperature T G and compares this with a predetermined value previously determined for the generator temperature T G . And when the generator temperature T G exceeds the predetermined value, the temperature management unit 45 determines that an abnormality has occurred in the generator 19 and stops the use of the power generation system 12. Similarly, the temperature management unit 45 acquires, for example, the engine oil temperature T oil , the engine water temperature T W , and the temperature of the second inverter T INV2 etc., and determines abnormalities in the engine 18 and the second inverter 20 by comparing with predetermined values previously determined for each. And when it is determined that there is an abnormality in the engine 18 or the second inverter 20, the temperature management unit 45 stops the use of the power generation system 1^{2}.

[0065] The temperature management unit 45 can execute temperature maintenance control to maintain the temperatures of each part constituting the hybrid vehicle 100 at temperatures within a predetermined temperature range (hereinafter referred to as target temperatures) as necessary. In the present embodiment, the temperature management unit 45 maintains the engine water temperature T W [[ID=*26]]at the target temperature by the heat generated in the generator 19 in order to enable a heating output according to the temperature setting of heating etc. The engine water temperature T WThe target temperature is determined by adaptation based on experiments, simulations, etc. The target temperature of the engine coolant temperature T W is, for example, a predetermined temperature T W1 (for example, about 50°C or more) and a predetermined temperature T W2 (for example, about 110°C or less). The predetermined temperature T W1 is the lower limit temperature to be maintained in order to respond to a heating request at any timing. The predetermined temperature T W2 is the upper limit temperature serving as a criterion for determining an abnormality such as that of the engine 18 or the like. And, the temperature control unit 45 includes a flow path mode control unit 48 for this temperature maintenance control.

[0066] The flow path mode control unit 48 controls the opening and closing of the valves V W , V 1a , V 1b and the valves V 2a , V 2b based on the engine coolant temperature T mode , the presence or absence of a heating request (on / off of the heater 21), the SOC of the battery 10, the road surface gradient, or a combination thereof, to switch the flow path mode C W of the cooling system 30 between the first flow path mode and the second flow path mode. That is, the flow path mode control unit 48 determines the necessity of heating discharge control based on the engine coolant temperature T mode , the presence or absence of a heating request (on / off of the heater 21), the SOC of the battery 10, the road surface gradient, or a combination thereof. And when it is determined that heating discharge control is necessary, the flow path mode control unit 48 maintains the flow path mode C mode of the cooling system 30 in the second flow path mode or switches it from the first flow path mode to the second flow path mode. On the other hand, when it is determined that heating discharge control is unnecessary, the flow path mode control unit 48 maintains the flow path mode C

[0067] of the cooling system 30 in the first flow path mode or switches it from the second flow path mode to the first flow path mode. modeThe on / off state of pump P2 can be controlled in accordance with the switching. For example, if the power generation system 12 does not generate power and the engine 18 and generator 19 are stopped, the power generation control unit 46 will, in principle, also stop (turn off) pump P2. Therefore, it is determined that heating discharge control is necessary, and the flow path mode C of the cooling system 30 is activated. mode When switching to the second flow path mode, the flow path mode control unit 48 activates (turns on) the pump P2. On the other hand, when it is determined that heating discharge control is unnecessary, the flow path mode C of the cooling system 30 is activated. mode When switching to the first flow path mode, if power generation by the power generation system 12 is not required, the flow path mode control unit 48 stops (turns off) the pump P2.

[0068] The flow path mode control unit 48 notifies the heating discharge control unit 47 of the result of its determination regarding the necessity of heating discharge control. When the flow path mode control unit 48 determines that heating discharge control is necessary, the heating discharge control unit 47 executes the heating discharge control.

[0069] Figure 4 is a block diagram showing the configuration of the generator controller 44. As shown in Figure 4, the generator controller 44 includes a rotation speed control unit 51, a current command value calculation unit 52, a current vector control unit 53, a coordinate transformation unit 54, a PWM conversion unit 55, and a coordinate transformation unit 56.

[0070] The rotation speed control unit 51 controls the rotation speed command value N G * And, rotational speed N G Based on this, the torque command value τ for the generator 19 is determined. G * The calculation is performed. When motoring engine 18, the rotational speed command value N G * This is set, for example, according to the required power consumption. When generating power, the rotational speed command value N G * The setting is configured to minimize the BSFC (Net Fuel Consumption Rate). When performing heating discharge control, the rotational speed command value N G * This is effectively set to zero. Rotational speed NG This is the actual rotational speed of the generator 19, which is detected using the rotation sensor 57 or calculated using the output of the rotation sensor 57. Rotational speed N G The rotational speed command value N G * It converges to the corresponding value. Torque command value τ G * is the generator torque τ G This is the command value (target value) for the rotational speed command value N G * The generator torque τ when the generator 19 is rotated at the corresponding rotational speed. G This represents the torque command value τ when performing heating discharge control. G * It is practically zero. The rotational speed control unit 51 controls the torque command value τ G * This is input to the current command value calculation unit 52.

[0071] The current command value calculation unit 52 calculates the torque command value τ G * , rotational speed N G , and battery voltage V dc Based on this, the d-axis current command value I of the generator 19 d * and q-axis current command value I q * (The following is the dq axis current command value I d * ,I q * The current command value calculation unit 52 calculates the dq axis current command value I d * ,I q * The d-axis current command value I is input to the current vector control unit 53. d * is the d-axis current I d This is the command value (target value) for the q-axis current command value I q * is the q-axis current I q This is the command value (target value) for that.

[0072] In this embodiment, the current command value calculation unit 52 calculates the torque command value τ based on experiments or simulations. G * , rotational speed N G , and battery voltage V dc And, the dq axis current command value I d * ,I q * It has a pre-defined current command value map (not shown) that associates the current command value with the torque command value τ. Therefore, the current command value calculation unit 52, in principle, refers to this current command value map to calculate the input torque command value τ G * , rotational speed N G , and battery voltage V dc Corresponding dq axis current command value I d * ,I q * Perform the calculation.

[0073] However, in the current command value map, the torque command value τ G * and rotational speed N G If it is zero, the dq axis current command value I d * ,I q * It is also zero. Therefore, when performing heating discharge control, the current command value calculation unit 52 calculates the q-axis current command value I regardless of the current command value map. q * Set to zero, and the d-axis current command value I d * Set the d-axis current command value I to a non-zero value. In particular, in this embodiment, the current command value calculation unit 52 calculates the d-axis current command value I which changes periodically when performing heating discharge control. d * This is set. Specifically, the current command value calculation unit 52 sets at least the d-axis current I d The d-axis current command value I, whose magnitude is periodically changed over time. d * Set it.

[0074] d-axis current command value I in heating discharge control d *For example, it commands an alternating current (including not only sinusoidal alternating current but also non-sinusoidal alternating current such as square wave and triangular wave alternating current) whose magnitude and direction (positive or negative) change periodically over time. Furthermore, it controls the d-axis current command value I in heating discharge control. d * This could, for example, be a command to apply a DC current intermittently in either a positive or negative direction over time. In any case, the d-axis current command value I in heating discharge control d * The d-axis current I causes iron losses such as hysteresis loss and eddy current loss in the stator of the generator 19, which heats the generator 19. d The command is issued. However, the d-axis current command value I in the heating discharge control is... d * Preferably, this commands a d-axis current whose positive and negative values ​​change periodically. This d-axis current command value I d * Based on this, the d-axis current I is applied to the generator 19. d This efficiently generates iron loss, allowing the generator 19 to be heated efficiently. Note that the d-axis current command value I d * The magnitude and period are set in advance based on the current value, temperature, etc., that the switching elements (not shown) constituting the second inverter 20 can tolerate.

[0075] The current vector control unit 53 controls the dq axis current command value I by so-called current vector control. d * ,I q * , d-axis current I d and q-axis current I q (Hereafter, dq axis current I d ,I q (and so on), as well as rotational speed N G Based on the d-axis voltage command value V d * and q-axis voltage command value V q * (The following is the dq axis voltage command value V d * ,V q * The following is calculated: d-axis voltage V d and q-axis voltage Vq (Below, dq axis voltage V d ,V q The voltages applied to the d-axis and q-axis of the generator 19 are the dq-axis voltage command values ​​V d * ,V q * This is the command value. The current vector control unit 53 controls the dq axis voltage command value V d * ,V q * This is input to the coordinate transformation unit 54.

[0076] The coordinate transformation unit 54 sets the dq axis voltage command value V d * ,V q * By performing a coordinate transformation, the three-phase voltage command value V, which is the voltage command value for each phase (UVW) of the generator 19, is obtained. u * ,V v * ,V w * The coordinate transformation unit 54 calculates the three-phase voltage command value V u * ,V v * ,V w * This is input to the PWM conversion unit 55.

[0077] The PWM conversion unit 55 controls the three-phase voltage command value V u * ,V v * ,V w * Accordingly, the second inverter 20 generates a PWM (Pulse Width Modulation) signal to drive the switching elements constituting the second inverter 20. The second inverter 20 drives the switching elements according to this PWM signal, thereby supplying voltage V to each of the UVW phases of the generator 19. u ,V v ,V w Apply current I u ,I v ,I w (Not shown in the diagram) is flowed. As a result, the generator 19 reaches a rotational speed command value N G* Corresponding rotational speed N G It rotates with a torque command value τ G * The corresponding generator torque τ G It is driven by the generator torque τ. In particular, in heating discharge control, it does not rotate and the generator torque τ G In a state where no such thing occurs, the generator 19 receives a d-axis current I d As the current flows, the generator 19 is heated.

[0078] The coordinate transformation unit 56 acquires the current flowing through each phase of the generator 19 and, through coordinate transformation, calculates the dq axis current I d ,I q The U-phase current I is calculated by the current sensor 58. u and V-phase current I v The U-phase current I is detected. Then, the coordinate transformation unit 56 detects the U-phase current I u and V-phase current I v Using W-phase current I w (Not shown in the diagram) is calculated, and the current I of each of these phases is calculated. u ,I v ,I w Based on the dq axis current I d ,I q The coordinate transformation unit 56 calculates the dq axis current I d ,I q This is input to the current vector control unit 53.

[0079] The generator controller 44 configured as described above functions as a power generation control unit 46 and a heating discharge control unit 47. In particular, the current command value calculation unit 52 calculates the q-axis current command value I q * Set to zero, and the d-axis current command value I d * When setting the q-axis current I to a non-zero value, q While keeping it at zero, the generator 19 receives the d-axis current I d Therefore, the current command value calculation unit 52 calculates the q-axis current command value I q * Set to zero, and the d-axis current command value I d *When set to a non-zero value, the generator controller 44 functions as a heating discharge control unit 47.

[0080] The operation of the heating discharge control in the hybrid vehicle 100 configured as described above will be explained below.

[0081] Figure 5 is a flowchart showing the operation of the heating discharge control. In Figure 5, for the sake of explanation, the engine water temperature T W The system determines whether or not to control the discharge for heating based on the heating requirement and the State of Charge (SOC) of the battery 10, but as mentioned above, the road surface gradient may also be taken into consideration.

[0082] As shown in Figure 5, in step S10, the temperature control unit 45 controls the generator temperature T G Engine oil temperature T oil Engine water temperature T W , and the second inverter temperature T INV2 To obtain the generator temperature T G Engine oil temperature T oil Engine water temperature T W , and the second inverter temperature T INV2 By comparing each of these values ​​with predetermined values, abnormalities in the engine 18 and generator 19 (i.e., power generation system 12) are determined. For example, engine water temperature T W However, the predetermined temperature T is set as the criterion for determining abnormality. W2 If the value is greater than this, the temperature control unit 45 determines that there is an abnormality in the power generation system 12. Generator temperature T G Engine oil temperature T oil Engine water temperature T W , and the second inverter temperature T INV2 If all of these values ​​are below the predetermined value and no abnormality is found in the power generation system 12, the process proceeds to step S12.

[0083] In step S12, the temperature control unit 45 controls the engine water temperature T W This is a predetermined temperature T, which is the lower limit temperature considering heating. W1By comparing with, whether the engine coolant temperature T can meet the heating requirement (i.e., whether the engine coolant temperature T is not too low) is determined. When the engine coolant temperature T is greater than a predetermined temperature T and the target temperature (TW1 < TW < TW2) is maintained, proceed to step S13. In step S13, the temperature control unit 45 checks whether there is a heating requirement, that is, whether the heater 21 is operating. When there is a heating requirement, proceed to step S14. On the other hand, in step S12, when the engine coolant temperature T is below the predetermined temperature T and the coolant water in the second cooling circuit 32, which is the heat source of the heater 21, is too cold, step S13 is skipped and proceed to step S14 regardless of whether there is a heating requirement. W whether it is maintained (i.e., whether the engine coolant temperature T W is not too low). When the engine coolant temperature T W is greater than a predetermined temperature T W1 and the target temperature (TW1 < TW < TW2) is maintained, proceed to step S13. In step S13, the temperature control unit 45 checks whether there is a heating requirement, that is, whether the heater 21 is operating. When there is a heating requirement, proceed to step S14. On the other hand, in step S12, when the engine coolant temperature T W is below the predetermined temperature T W1 and the coolant water in the second cooling circuit 32, which is the heat source of the heater 21, is too cold, step S13 is skipped and proceed to step S14 regardless of whether there is a heating requirement.

[0084] In step S14, the temperature control unit 45 obtains the SOC of the battery 10 and compares it with the upper limit threshold S H . When the SOC of the battery 10 is greater than or equal to the upper limit threshold S H and the battery 10 is fully charged, proceed to step S15.

[0085] In step S15, the flow path mode control unit 48 switches the flow path mode C of the cooling system 30 to the second flow path mode. Then, in step S16, the flow path mode control unit 48 operates the pump P2 of the second cooling circuit 32. As a result, the coolant water in the second cooling circuit 32 circulates through the engine 18, the generator 19, and the heater 21. mode to the second flow path mode. Then, in step S16, the flow path mode control unit 48 operates the pump P2 of the second cooling circuit 32. As a result, the coolant water in the second cooling circuit 32 circulates through the engine 18, the generator 19, and the heater 21.

[0086] Next, in step S17, the heating discharge control unit 47 maintains the q-axis current command value I q * at zero (I q * = 0), and at the same time, makes the d-axis current command value I d * a non-zero value (I d *dq axis current command value I for d axis discharge (≠0) d * ,I q * The calculation is performed. Then, in step S18, the heating discharge control unit 47 sets the dq axis current command value I for this d axis discharge. d * ,I q * Accordingly, the generator 19 receives the d-axis current I d By selectively flowing the d-axis discharge, the generator 19 is heated. As a result, the cooling water in the second cooling circuit 32 flows into the heater 21 carrying the heat generated by the generator 19 due to the d-axis discharge. Consequently, even when the power generation system 12 is not generating power and the engine 18 and generator 19 are stopped, the heater 21 can provide heating using the heat generated by the generator 19 due to the d-axis discharge.

[0087] In step S11, the generator temperature T G Engine oil temperature T oil Engine water temperature T W , or the second inverter temperature T INV2 If any of the values ​​exceeds a predetermined value and it is determined that there is an abnormality in the power generation system 12, the process proceeds to step S19. This is a scenario where the power generation system 12 cannot be used due to the abnormality. Also, if it is determined in step S13 that the heater 21 is not operating and there is no heating request, the process proceeds to step S19. This is a scenario where the engine water temperature T W This is a scenario where the temperature is maintained at the target temperature, there is no heating request, and there is no need to perform heating discharge control. Also, in step S14, the SOC of battery 10 is above the upper threshold S H If it is smaller than this, proceed to step S19. This is a scenario where the battery 10 has not yet reached full charge and the power generation system 12 can operate, so heating discharge control by d-axis discharge is not necessary. Here, the flow path mode C of the cooling system 30 is used. mode To switch this, we proceed to step S19 for convenience.

[0088] In step S19, if the power generation system 12 is generating power and the engine 18 is running, the power generation control unit 46 stops the engine 18. Also, if the power generation system 12 is not generating power and the engine 18 is stopped, the engine 18 remains stopped.

[0089] In step S20, power to the generator 19 is stopped, and in step S21, the pump P2 of the second cooling circuit 32 is stopped. Then, in step S22, the flow path mode control unit 48 sets the flow path mode C of the cooling system 30. mode The system switches to the first flow path mode. As a result, the generator 19 is cooled by the cooling water of the first cooling circuit 31. When there is a demand for power generation due to a decrease in SOC, etc., or when the operation (power generation) of the engine 18 is necessary to meet the heating demand and is possible, the flow path mode C of the cooling system 30 is switched. mode While the system is in the first flow path mode, the power generation system 12 is operated as needed.

[0090] Figure 6 shows the engine water temperature T W This is a time chart that schematically shows the temporal progression of such events.

[0091] Figure 6(A) shows the altitude A of the hybrid vehicle 100. L [m] is shown. Figure 6(B) shows the vehicle speed V [km / h] of hybrid vehicle 100. Figure 6(C) shows the brake operation amount Br [%]. Figure 6(D) shows the accelerator operation amount Ac [%]. Figure 6(E) shows the generator rotation speed N G [rpm] is shown. Figure 6(F) shows the SOC[%] of battery 10. Figure 6(G) shows the output at the output shaft of the motor 16 (hereinafter referred to as motor shaft output P). m Figure 6(H) shows the output at the input / output shaft of the generator 19 (hereinafter referred to as generator shaft output P). G This indicates [kW]. Figure 6(I) shows the heat loss H in the generator 19. G Figure 6(J) shows the fuel flow rate FF [L / h] in the power generation system 12. Figure 6(K) shows the engine water temperature T W[°C] is shown. Figure 6(L) shows the flow path mode C of the cooling system 30. mode This is shown. In Figure 6(L), "0" represents the first flow path mode, and "1" represents the second flow path mode.

[0092] In Figures 6(E) to 6(L), the solid lines show an example of heating discharge control using d-axis discharge according to this embodiment, while the dashed lines show the control of the comparative example. The control of the comparative example is one in which, when the battery 10 is fully charged, the power of the battery 10 is consumed by the motoring of the engine 18. In the control of the comparative example, the temperature of the cooling water circulating to the heater 21 is maintained by generating electricity in the power generation system 12 to the extent of the surplus power generated by this motoring.

[0093] As shown in Figure 6(A), the hybrid vehicle 100 is traveling at high altitude from time t0 to time t1, and then travels downhill from time t1 onward. Here, from time t3 onward, a constant brake operation amount Br is maintained, and the hybrid vehicle 100 travels downhill while gradually reducing its vehicle speed V. As shown in Figure 6(B), the hybrid vehicle 100, which was traveling at a constant vehicle speed V until time t1, increases its vehicle speed V when it enters a downhill road at time t1. Therefore, as shown in Figures 6(C) and 6(D), the accelerator is released at time t2, and braking is initiated at time t3.

[0094] Also, the generator rotation speed N in Figure 6(E) G , Generator shaft output P in Figure 6(H) G Furthermore, as shown in the fuel flow rate FF in Figure 6(J), in both this embodiment and the comparative example, the power generation system 12 generates power to charge the battery 10 until time t2. Therefore, as shown in Figure 6(F), the State of Charge (SOC) of the battery 10 is above the upper threshold S until time t2 when power generation is stopped. H Even if it doesn't reach that value, a value close to it is maintained.

[0095] Therefore, when the brake is operated at time t2, as shown in Figure 6(G), the motor shaft output P starts from time t3 when the brake operation begins.m This becomes negative, generating regenerative braking force in the hybrid vehicle 100. As a result, even when power generation by the power generation system 12 is stopped, as shown in Figure 6(F), the battery 10 is charged by regenerative power, and its SOC is approximately at the upper threshold S at time t4. H This concludes the explanation. Subsequently, the State of Charge (SOC) of battery 10 reaches almost its limit (100%). These points are common to this embodiment and the comparative example.

[0096] Below, we will compare the heating discharge control of this embodiment with the control of the comparative example in the driving scenario described above.

[0097] In the comparative example control, as shown by the dashed line in Figure 6(K), when power generation stops at time t2, the engine water temperature T W It also begins to decrease. And at time t5, the predetermined temperature T W1 It will be lower than (the lower limit for the target temperature for heating).

[0098] In this case, in the comparative example's control, the regenerative control of the motor 16 is stopped at time t5, as shown by the dashed line in Figure 6(G). At the same time, as shown by the dashed line in Figure 6(H), in the comparative example's control, from time t5, the generator shaft output P G This is controlled to a negative value. As a result, as shown by the dashed line in Figure 6(E), the engine 18 is motored and the stored power in the battery 10 is consumed. Consequently, as shown by the dashed line in Figure 6(F), in the comparative example control, the SOC of the battery 10 decreases from time t5.

[0099] Subsequently, in the control of the comparative example, power generation is performed by the power generation system 12, thereby increasing the engine water temperature T W This increases the generator shaft output P. Specifically, as shown by the dashed lines in Figures 6(H) and 6(J), in the comparative example, the engine 18 is started from time t6, and the generator shaft output P is increased. G By positively controlling this, power generation is performed by the power generation system 12. As a result, as shown by the dashed line in Figure 6(K), in the control of the comparative example, the engine water temperature T W It will rise.

[0100] Thus, in the control of the comparative example, as described above, power consumption by motoring and power generation are repeated alternately. As a result, the engine water temperature T W The temperature gradually rises. As shown by the dashed line in Figure 6(K), the engine water temperature T W at a predetermined temperature T W1 If the temperature falls below this level, heater 21 may not be able to adequately meet the heating requirements.

[0101] In the heating discharge control of this embodiment, as shown by the solid line in Figure 6(K), when power generation stops at time t2, the engine water temperature T W It also begins to decrease. However, as shown by the solid line in Figure 6(F), shortly after the power generation stops, the SOC of battery 10 reaches the upper threshold S at time t4 due to the accumulation of regenerative power. H As a result, as shown in Figure 6(L), the flow mode of the cooling system 30 is switched to the second flow mode, and the generator 19 is connected to the second cooling circuit 32 that cools the engine 18. Then, without rotating the generator 19 as shown by the solid line in Figure 6(E), the generator 19 is heated by the d-axis discharge as shown by the solid line in Figure 6(I). As a result, the cooling water that has been heated by the d-axis discharge in the generator 19 flows to the heater 21. Consequently, in the heating discharge control of this embodiment, even without generating electricity with the power generation system 12 and operating the engine 18, the engine water temperature T is reduced as shown by the solid line in Figure 6(K). W However, at a predetermined temperature T W1 The target temperature is maintained above this level. Therefore, in the heating discharge control of this embodiment, the heater 21 can maintain sufficient heating output to meet the heating requirements.

[0102] Furthermore, in the heating discharge control of this embodiment, regenerative control of the motor 16 can also be continued, as shown by the solid line in Figure 6(G). In the driving scene of Figure 6, the energy for the heating discharge control is substantially supplied by regenerative power.

[0103] Figure 7 is an explanatory diagram showing the schematic configuration of a modified hybrid vehicle 101. As shown in Figure 7, the modified hybrid vehicle 101 is configured such that the generator 19 of the power generation system 12 and the gearbox 17 of the vehicle drive system 11 can be arbitrarily connected or disconnected by a clutch 60. In other words, in the modified hybrid vehicle 101, the generator 19 can be driven using the power from the battery 10, and that power can be converted into the driving force of the hybrid vehicle 101.

[0104] However, in the modified hybrid vehicle 101, for example, when the battery 10 is fully charged, the power generation system 12 (engine 18) cannot be operated. This is the same as in the hybrid vehicle 100 according to the above embodiment. For this reason, even in the modified hybrid vehicle 101, the heater 21 may not be able to meet the heating demand, but according to the heating discharge control of the above embodiment, the engine water temperature T W This allows the system to maintain the target temperature and meet heating requirements. In other words, the heating discharge control of the above embodiment is also suitable for the modified hybrid vehicle 101.

[0105] In the above embodiments and modifications, the engine water temperature T W This is closely correlated with the temperature of the heated air that the heater 21 blows into the passenger compartment. In other words, in heating discharge control, the engine water temperature T W This is substantially equivalent to the temperature of the heated air. For this reason, in the above embodiment and modified example, the engine water temperature T W The portion that uses this as an indicator is replaced in whole or in part with the temperature of the heated air.

[0106] In the above embodiments and modifications, an example was described in which heating discharge control by d-axis discharge is performed when the battery 10 is fully charged, but the invention is not limited to this. Even if the battery 10 is not fully charged, heating discharge control by d-axis discharge can be actively utilized to raise the engine water temperature T W This can be maintained. However, as in the above embodiment and its modifications, the heating discharge control in the above embodiment and its modifications is particularly effective when the battery 10 is fully charged and the engine 18 cannot be operated.

[0107] In the above embodiments and modifications, the flow path mode of the cooling system 30 is switched between a first flow path mode and a second flow path mode, but it is not limited thereto. As long as the cooling system 30 can transport heat from the engine 18 to the heater 21 and, at least as necessary, heat from the generator 19 to the heater 21, the flow path of the cooling water, the flow path of the first flow path mode, and the flow path of the second flow path mode can all be arbitrarily modified.

[0108] As described above, the control method for a hybrid vehicle according to the above embodiment and its modifications is a control method for a hybrid vehicle comprising: a battery 10 for storing electricity; an electric motor 16 that generates driving force to the wheels 14 using the electricity from the battery 10; a power generation system 12 that includes an engine 18 and a generator 19 and generates electricity to be stored in the battery 10; and a heater 21 that heats the passenger compartment using the heat of the refrigerant (cooling water) that cools the engine 18. In this control method for a hybrid vehicle, when the engine 18 and the generator 19 are stopped from rotating, the torque generated by the generator 19 (generator torque τ) is controlled. G By discharging power from the battery 10 to the generator 19 while keeping the refrigerant temperature (engine water temperature T) at zero, the generator 19 is heated. The heat generated by the generator 19 then raises the temperature of the refrigerant (engine water temperature T). W ) is a predetermined target temperature (T W1 <T W <T W2 ) is maintained.

[0109] In this way, by heating the generator 19 with the power from the battery 10 and using the heat from the generator 19 to maintain the heating capacity of the heater 21, the heating capacity of the heater 21 can be maintained even in situations where the power generation system 12 (engine 18) cannot be operated.

[0110] Of course, in order to bring the power generation system 12 into an operational state, it is conceivable to consume power from the battery 10 by using the motoring of the engine 18, a heater (not shown) that heats the coolant, or a heater (not shown) that heats the passenger compartment using the power of the battery 10. However, as explained in the above embodiment (see Figure 6(K), etc.), the control method for the hybrid vehicle according to the above embodiment and its modified form makes it easier to maintain heating capacity than when the power of the battery 10 is consumed by the motoring of the engine 18. Furthermore, the control method for the hybrid vehicle according to the above embodiment and its modified form can be implemented at a lower cost compared to cases where additional heaters such as a heater that heats the coolant or a heater that heats the passenger compartment using the power of the battery 10 are provided. In particular, typically, the heating output of a heater that heats the passenger compartment using the power of the battery 10 is about 1 kW, and the heating requirement is about 5 kW to 7 kW. For this reason, a heater that heats the passenger compartment using the power of the battery 10 may not be able to meet the heating requirement. In contrast, the control method for the hybrid vehicle according to the above embodiment and its modified form can meet even typical heating requirements.

[0111] While heaters with a heating output of around 7kW that heat the passenger compartment using the power of battery 10 are known, such high-output heaters require high voltage, are large in size, and are correspondingly expensive. Therefore, adding a high-output heater presents problems in terms of vehicle packaging (layout of additional heater, etc.) and cost (additional heater cost). In contrast, the control method for a hybrid vehicle according to the above embodiment and its modifications has the advantage of being able to meet typical heating requirements without creating problems with vehicle packaging and cost.

[0112] Furthermore, the control method for the hybrid vehicle according to the above embodiment and its modified form is compatible with regenerative control of the electric motor 16, as explained in the above embodiment (see Figure 6(G), etc.). For this reason, the control method for the hybrid vehicle according to the above embodiment and its modified form has the advantage of being more energy efficient compared to control methods that consume (waste) the power of the battery 10 through motoring of the engine 18, etc.

[0113] In the hybrid vehicle control method according to the above embodiment and modified example, the charge level (SOC) of the battery 10 is set to a predetermined threshold (upper threshold S). H When the temperature of the refrigerant (engine water temperature T) is above the temperature of the generator 19, the heat generated by the generator 19 causes the refrigerant temperature to rise. W ) is the target temperature (T W1 <T W <T W2 ) is maintained. Thus, since a situation where the State of Charge (SOC) of the battery 10 is fully charged is a typical situation in which the power generation system 12 cannot be operated, the control method of the hybrid vehicle according to the above embodiment and its modified form, which utilizes the heat generated by the generator 19, is particularly suitable.

[0114] The control method for a hybrid vehicle according to the above embodiment and modified examples is, in particular, one in which the state of charge (SOC) is at least a threshold (upper threshold S). H ) or higher, and when the heater (heater 21) is operating, the heat generated by the generator 19 causes the refrigerant temperature (engine water temperature T) to rise. W ) is the target temperature (T W1 <T W <T W2 ) is maintained. Thus, when the State of Charge (SOC) of the battery 10 is fully charged and there is a heating request, it is a situation in which heating by the heater 21 is explicitly required, even though the power generation system 12 cannot be operated. Therefore, the control method of the hybrid vehicle according to the above embodiment and its modifications, which utilize the heat generated by the generator 19, is particularly suitable.

[0115] In the hybrid vehicle control method according to the above embodiment and modified example, information relating to the gradient of the road surface on which the hybrid vehicle 100 is traveling is acquired, and based on the information relating to the gradient of the road surface, it is determined whether or not the road surface on which the hybrid vehicle 100 is traveling is on a downhill slope. At a minimum, if the road surface on which the hybrid vehicle 100 is traveling is on a downhill slope, and the state of charge (SOC) is at a threshold (upper threshold S) H When the temperature of the refrigerant (engine water temperature T) is above the temperature of the generator 19, the heat generated by the generator 19 causes the refrigerant temperature to rise. W ) is the target temperature (T W1 <T W <T W2 ) is maintained. Thus, when the State of Charge (SOC) of the battery 10 is fully charged and the vehicle is traveling downhill, the vehicle is charged by regenerative power even though the power generation system 12 cannot be operated. Therefore, the control method of the hybrid vehicle according to the above embodiment and its modified form, which utilizes the heat generated by the generator 19, is particularly suitable. Furthermore, it is possible to continue regenerative control of the electric motor 16, and the control method of the hybrid vehicle according to the above embodiment and its modified form has the advantage of being realized with high energy efficiency.

[0116] In the control method for a hybrid vehicle according to the above embodiment and its modified form, the refrigerant temperature (engine water temperature T) W ) is a predetermined temperature (predetermined temperature T W1 When the temperature is lower than ), the heat generated by the generator 19 causes the refrigerant temperature (engine water temperature T) to decrease. W ) is the target temperature (T W1 <T W <T W2 ) is maintained. Thus, the engine water temperature T W at a predetermined temperature T W1 When it is smaller than this, the heat generated by the generator 19 is used to heat the engine water temperature T, regardless of whether there is a heating request or not. W Maintaining this setting ensures that the heating capacity of heater 21 is constantly maintained, allowing for accurate response to heating demands that arise at any given time.

[0117] In the control method for a hybrid vehicle according to the above embodiment and modified example, the d-axis current I of the generator 19 d and q-axis current Iq Of these, the q-axis current I q By keeping it at zero, the torque generated by the generator 19 (generator torque τ) G ) is kept at zero, and the d-axis current I d By flowing this discharge, the power from the battery 10 is discharged to the generator 19. In this way, when heating discharge control is performed by d-axis discharge, the generator 19 and engine 18 do not rotate and remain stopped. As a result, the exhaust from the power generation system 12 is kept clean. Specifically, the exhaust from the engine 18 is filtered by a catalyst (not shown) to remove nitrogen oxides (NOx). x The exhaust gas is treated with a catalyst to prevent the generation of harmful substances such as ) before being discharged. However, even when power generation is not taking place, when the generator 19 and engine 18 rotate, exhaust gas (air) is sent to the catalyst, causing the catalyst's temperature to drop, and oxygen is adsorbed onto the catalyst that adsorbs oxygen. As a result, when the power generation system 12 is generating power, the catalyst's processing capacity may be reduced. Therefore, as described above, by controlling the heating discharge without rotating the generator 19 (and engine 18) using d-axis discharge, the catalyst's processing capacity is maintained even when the power generation system 12 subsequently generates power, making it easier to keep the exhaust gas from the power generation system 12 clean.

[0118] In the control method for a hybrid vehicle according to the above embodiment and modified example, the d-axis current I d This is composed of a current whose positive and negative values ​​change periodically. Thus, the d-axis current I used for d-axis discharge d By making the current change in polarity periodically, the generator 19 is heated particularly efficiently due to hysteresis loss, eddy current loss, and the like. As a result, a control method for a hybrid vehicle according to the above embodiment and its modifications is realized with high energy efficiency.

[0119] In the hybrid vehicle control method according to the above embodiment and modified example, the flow path of the refrigerant (cooling water) is switched from a first flow path mode in which the refrigerant (cooling water) circulates through the engine 18 and heater (heater 21) to a second flow path mode in which the refrigerant (cooling water) circulates through the engine 18, heater (heater 21), and generator 19, thereby reducing the temperature of the refrigerant (engine water temperature T) by the heat generated by the generator 19. W ) is the target temperature (T W1 <T W <T W2 ) is maintained. In this way, by switching the flow mode of the cooling system 30, the heat generated by the generator 19 is circulated to the heater 21, and the engine water temperature T is maintained. W When maintaining this configuration, heat can be transported particularly efficiently while utilizing existing flow paths. Furthermore, compared to cases where additional heaters are installed, such as heaters for heating the cooling water or heaters for heating the passenger compartment using the power of the battery 10, the control method for the hybrid vehicle according to the above embodiment and its modifications can be realized at a lower cost.

[0120] The control device (controller 13) of the hybrid vehicle according to the above embodiment and modified example comprises a battery 10 for storing electricity, an electric motor 16 that generates driving force for the wheels 14 using the electricity from the battery 10, a power generation system 12 that includes an engine 18 and a generator 19 and generates electricity to be stored in the battery 10, and a heater (heater 21) that heats the passenger compartment using the heat of the refrigerant (cooling water) that cools the engine 18. This control device (controller 13) controls the torque (generator torque τ) generated by the generator 19 when the engine 18 and generator 19 are stopped rotating. G A heating discharge control unit 47 heats the generator 19 by discharging power from the battery 10 to the generator 19 while maintaining the temperature at zero, and the heat generated by the generator 19 heats the refrigerant temperature (engine water temperature T). W ) predetermined target temperature (T W1 <T W <T W2 It includes a temperature control unit 45 that maintains the temperature at )

[0121] In this way, by configuring the controller 13 of the hybrid vehicle 100 to include a heating discharge control unit 47 and a temperature control unit 45, the heating capacity of the heater 21 is maintained even when the power generation system 12 (engine 18) cannot be operated.

[0122] Although embodiments of the present invention have been described above, the configurations described in the above embodiments and each of the modifications represent only a part of the application examples of the present invention and are not intended to limit the technical scope of the present invention. For example, the control method for a hybrid vehicle according to the above embodiments and modifications is suitable for situations other than when the hybrid vehicle 100 is traveling downhill. [Explanation of symbols]

[0123] 10: Battery, 11: Vehicle drive system, 12: Power generation system, 13: Controller, 14: Wheels, 15: First inverter, 16: Electric motor, 17: Gearbox, 18: Engine, 19: Generator, 20: Second inverter, 21: Heater, 30: Cooling system, 31: First cooling circuit, 32: Second cooling circuit, 33: Coupling circuit, 34: Basic flow path, 35: Short-circuit flow path, 36: Bypass flow path, 37: Radiator, 38: Basic flow path, 39: Bypass flow path, 41: Drive controller, 42: Battery controller, 43: Engine controller, 44: Power generation Machine controller, 45: Temperature control unit, 46: Power generation control unit, 47: Heating discharge control unit, 48: Flow mode control unit, 51: Rotation speed control unit, 52: Current command value calculation unit, 53: Current vector control unit, 54: Coordinate transformation unit, 55: PWM conversion unit, 56: Coordinate transformation unit, 57: Rotation sensor, 58: Current sensor, 60: Clutch, 100: Hybrid vehicle, 101: Hybrid vehicle, 200: Cooling system, 201: First cooling circuit, 202: Second cooling circuit, 211: Electric motor, 212: Generator, 213: Radiator, 214: Engine, 215: Heater

Claims

1. A control method for a hybrid vehicle comprising: a battery for storing electricity; an electric motor that generates driving force for the wheels using the electricity from the battery; a power generation system including an engine and a generator that generates electricity to be stored in the battery; and a heater that heats the passenger compartment using the heat from a refrigerant that cools the engine, While the engine and the generator are stopped rotating, the generator is heated by discharging power from the battery to the generator while maintaining the torque generated by the generator at zero. When the battery's charge level is above a predetermined threshold and the heater is in operation, the heat generated by the generator maintains the refrigerant's temperature at a target temperature. Control methods for hybrid vehicles.

2. A control method for a hybrid vehicle according to claim 1, By switching the flow path of the refrigerant from a first flow path mode in which the refrigerant circulates through the engine and the heater to a second flow path mode in which the refrigerant circulates through the engine, the heater, and the generator, the temperature of the refrigerant is maintained at the target temperature by the heat generated by the generator. Control methods for hybrid vehicles.

3. A control device for a hybrid vehicle comprising: a battery for storing electricity; an electric motor that generates driving force for the wheels using the electricity from the battery; a power generation system including an engine and a generator that generates electricity to be stored in the battery; and a heater that heats the passenger compartment using the heat from a refrigerant that cools the engine, A heating discharge control unit heats the generator by discharging power from the battery to the generator while maintaining the torque generated by the generator at zero, when the engine and the generator are stopped rotating. A temperature control unit maintains the temperature of the refrigerant at a predetermined target temperature using the heat generated by the generator when the battery charge level is above a predetermined threshold and the heater is in operation. A control device for hybrid vehicles, equipped with the following features.

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