JP7800307B2 - Energy management method, energy management device, program, and storage medium - Google Patents

Description

The present invention relates to a vehicle energy management method, an energy management device, a program, and a storage medium.

Patent Document 1 discloses an energy management device that creates a control plan based on driving route information and vehicle information to minimize energy consumption when a hybrid vehicle travels along a driving route, and corrects the created control plan when the driving mode is switched in a specific way.

Patent Document 2 also discloses an optimal operating point determination method that uses a net fuel consumption rate map to calculate a fuel consumption rate equivalent coefficient, which is a factor for quantitatively comparing the amount of fuel consumed by the engine and the electrical energy consumed by the motor, and determines the optimal operating point according to the battery's state of charge based on that fuel consumption rate equivalent coefficient.

JP 2016-159830 A JP 2009-143524 A

Vehicle energy management is performed, for example, based on a brake specific fuel consumption (BSFC) map. However, energy management based on the BSFC map may not be optimal. For example, in a series hybrid vehicle, even when energy management is performed using the BSFC map, there may be situations in which the battery must be discharged by motoring (idling) the engine used for generating electricity or using a battery-powered heater. In other words, there is room for improvement in energy management based on the BSFC map.

The present invention aims to provide an energy management method and energy management device that can reduce long-term or cumulative fuel consumption in a power generation system when heating is used, compared to energy management using a BSFC map.

One aspect of the present invention is an energy management method for a vehicle including a battery that supplies power to a drive motor, a power generation system that generates power using fuel to store in the battery, and a heater. In this energy management method, running power consumption, which is the power consumed by the drive motor while the vehicle is running, is estimated. Heating energy corresponding to the output required of the heater is also obtained. An operating point of the power generation system is then determined based on the running power consumption and the heating energy. Furthermore, time-series data of the running power consumption is recorded, a moving average of the running power consumption is calculated based on the time-series data, and the running power consumption is estimated based on the moving average.
In addition, in one embodiment, the driving power consumption is calculated by adding a moving average and a correction value according to the battery's charging rate, and if the charging rate is higher than a predetermined reference value, the correction value is set to a negative value, and if the charging rate is lower than the reference value, the correction value is set to a positive value.
In another embodiment, the moving average is calculated for a predetermined period of time, and the predetermined period of time is reduced as the battery's charge rate decreases.
In yet another embodiment, the moving average is reset when the vehicle speed exceeds a predetermined threshold or when the vehicle speed falls below the threshold.

The present invention provides an energy management method and energy management device that can reduce long-term or cumulative fuel consumption in a power generation system when heating is used, compared to energy management using a BSFC map.

FIG. 1 is a block diagram showing a schematic configuration of a vehicle. FIG. 2 is an explanatory diagram showing the relationship between engine water temperature and power generation control. FIG. 3 is a block diagram showing the configuration of a controller related to energy management of a vehicle. FIG. 4 is a flowchart of the power generation control. FIG. 5 is an explanatory diagram showing the operating points of the power generation system based on the BSFC map and the fuel consumption map. FIG. 6 is a graph showing the changes in BSFC and fuel consumption when driving in an urban area. FIG. 7 is an explanatory diagram showing the operating points of the power generation system based on the corrected fuel consumption rate map when the total heating energy is 4000 W when traveling in an urban area. FIG. 8 is a graph showing the transition of BSFC, fuel consumption, etc. when the total heating energy is 4000 W when traveling in an urban area. FIG. 9 is a graph showing the results of WLTC running while performing energy management using the power generation control of the first embodiment. FIG. 10 is a graph showing the relationship between the traveling power consumption and the moving average of the traveling power consumption over the past five minutes. FIG. 11 is a graph showing the relationship between the coefficient _a1 and the coefficient _a2 . FIG. 12 is a graph showing the results of WLTC running while performing energy management using power generation control according to the second embodiment. FIG. 13 is a graph showing the traveling power consumption, the moving average of the traveling power consumption over the past five minutes, and the moving average of the traveling power consumption over the past one minute. FIG. 14 is a flowchart relating to the determination of the operating point of the power generation system and the second heater output in real time.

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

[First embodiment]
Fig. 1 is a block diagram showing a schematic configuration of a vehicle 100. As shown in Fig. 1, the vehicle 100 according to this embodiment is a so-called series hybrid vehicle, and includes a drive motor 10, a battery 11, a power generation system 12, a heater 13, and a controller 14. However, the vehicle 100 may be a hybrid vehicle of another type.

The drive motor 10 is an electric motor that generates driving force for the vehicle 100 and is connected to drive wheels (not shown). The drive motor 10 is driven by power supplied from the battery 11.

The battery 11 stores power to be supplied to the drive motor 10, heater 13, and other auxiliary equipment. The battery 11 is charged with power generated by the power generation system 12. The battery 11 is also charged with power input from the drive motor 10 through so-called regenerative control.

In this embodiment, power generation by the power generation system 12 is controlled so that the charging rate or state of charge (hereinafter referred to as SOC (State Of Charge)) of the battery 11 is maintained within a predetermined range (hereinafter referred to as a predetermined charging range). Specifically, for energy management and the like, a power generation on threshold _Th1 and a power generation off threshold _Th2 are set for the SOC of the battery 11. When the SOC becomes smaller than the power generation on threshold _Th1 or when it is determined that the SOC is likely to become smaller than the power generation on threshold Th1, the power generation system 12 starts power generation and charges the battery 11 in principle. On the other hand, when the SOC becomes larger than the power generation off threshold _Th2 or when it is determined that the SOC is likely to become larger than the power generation off threshold Th2, the power generation system 12 stops power generation in principle. When the SOC is equal to or greater than the power generation on threshold _Th1 and equal to or less than the power generation off threshold _Th2 , power generation by the power generation system 12 is turned on or off as appropriate depending on factors other than the SOC.

Furthermore, for safe operation of the battery 11, a tolerance value _Th3 is set for the SOC of the battery 11. When the SOC is smaller than the tolerance value _Th3 , power generation by the power generation system 12 and charging of the battery 11 are permitted. Therefore, the power generation on threshold _Th1 and the power generation off threshold _Th2 are set to values that are at least smaller than the tolerance value _Th3 . The tolerance value _Th3 is set in advance according to the specifications of the battery 11, etc. The power generation on threshold _Th1 and the power generation off threshold _Th2 are set in advance by adaptation based on experiments, simulations, etc. for energy management, etc.

The power generation system 12 uses fuel to generate electricity to be stored in the battery 11. In this embodiment, the power generation system 12 includes an engine 16 and a generator 17. The engine 16 is an internal combustion engine driven by gasoline or other fuel. The power generated by the engine 16 is input to the generator 17. The generator 17 rotates using the power of the engine 16 and generates electricity. The power generated by the generator 17 is input to the battery 11. Note that the generator 17 may be driven by the power of the battery 11, causing the engine 16 to idle (so-called motoring), thereby discharging the battery 11. However, in this embodiment, energy management of the vehicle 100 is performed so that, in principle, energy does not need to be consumed by motoring.

The heater 13 heats the interior of the vehicle 100. The heater 13 is part of an HVAC (Heating, Ventilation, and Air Conditioning) system (not shown) equipped in the vehicle 100. In this embodiment, the heater 13 includes a first heater 18 and a second heater 19.

The first heater 18 is a first heating device that uses heat generated by the power generation system 12 to provide heating. In this embodiment, the first heater 18 is provided in a circulation path for coolant or other refrigerant (hereinafter referred to as coolant) that cools the engine 16. The first heater 18 supplies warm air into the passenger compartment of the vehicle 100 by blowing air into the circulation path for the coolant heated by the engine 16. The load of the first heater 18 in the heater 13, i.e., the output of the first heater 18 (hereinafter referred to as first heater output T [W]), can be obtained (calculated) based on the temperature of the coolant (hereinafter referred to as engine water temperature T _W [°C]). The engine water temperature T _W is a parameter that represents the temperature of the engine 16 and essentially functions as a parameter that represents the temperature of the power generation system 12.

2A and 2B are explanatory diagrams showing the relationship between engine water temperature T _W and power generation control. Fig. 2A shows the transition of engine water temperature T _W , and Fig. 2B shows the timing of turning on/off power generation by the power generation system 12. As shown in Fig. 2, in this embodiment, for energy management, the on/off of power generation by the power generation system 12 is controlled so that the engine water temperature T _W falls within a predetermined temperature range.

Specifically, a power generation on threshold T _W1 and a power generation off threshold T _W2 are set for the engine water temperature T _W. When the engine water temperature T _W becomes smaller than the power generation on threshold T _W1 , or when it is determined that this is likely to occur, the power generation system 12 starts power generation in principle. As a result, the engine water temperature T _W rises due to heat generated by the power generation system 12 (engine 16). On the other hand, when the engine water temperature T _W becomes larger than the power generation off threshold T _W2 , or when it is determined that this is likely to occur, the power generation system 12 stops power generation in principle, and the coolant for the engine 16 is cooled by using the first heater 18. As a result, the engine water temperature T _W drops.

Furthermore, to ensure safe operation of the power generation system 12, a tolerance value T _W3 is set for the engine water temperature T _W. When the engine water temperature T _W is lower than the tolerance value T _W3 , the power generation system 12 is permitted to operate without using a radiator (not shown). Therefore, the power generation on threshold value T _W1 and the power generation off threshold value T _W2 are set to values that are at least lower than the tolerance value T _W3 . The tolerance value T _W3 is set in advance according to the specifications of the power generation system 12, etc. In this embodiment, energy management of the vehicle 100 is performed so that, in principle, it is not necessary to rapidly cool the coolant for the engine 16 using a radiator.

In this way, the engine water temperature T _W is generally maintained within a temperature range from the power generation on threshold T _W1 (lower limit temperature) to the power generation off threshold T _W2 (upper limit temperature). The first heater output T [W] varies within a range that generally corresponds to the temperature range that the engine water temperature T _W can take (T _W1 ≦ T _W ≦ T _W2 ).

When the engine water temperature T _W is equal to or higher than the power generation on threshold T _W1 and equal to or lower than the power generation off threshold T _W2 , power generation by the power generation system 12 may be turned on or off as appropriate depending on factors other than the engine water temperature T _W. The power generation on threshold T _W1 and the power generation off threshold T _W2 are determined in advance by experiment, simulation, or the like.

The second heater 19 (see Figure 1) is a second heating device that uses power from the battery 11 for heating. In this embodiment, the second heater 19 is, for example, a PTC (Positive Temperature Coefficient) heater.

In conventional vehicles, heaters such as the first heater 18 that utilize heat generated by the engine 16 or power generation system 12 are typically used for heating, and electrically powered heaters such as the second heater 19 are used only as an auxiliary. Furthermore, electrically powered heaters such as the second heater 19 may be energized when it is necessary to discharge the battery 11. In other words, in conventional vehicles, the situations in which electrically powered heaters such as the second heater 19 are used are limited.

In contrast, in this embodiment, the second heater 19 is used more actively for the energy management of the vehicle 100, i.e., to reduce the fuel consumption F of the power generation system 12 (engine 16). Specifically, the load of the second heater 19 in the heater 13, i.e., the output of the second heater 19 (hereinafter referred to as the second heater output P [W]), is set so as to reduce the fuel consumption F of the power generation system 12 (engine 16). In principle, the heater 13 achieves the required heating by having the first heater 18 and the second heater 19 operate in cooperation. The total heating energy H [W] required by the heater 13 is the sum of the first heater output T and the second heater output P. Furthermore, the total heating energy H is determined according to the room temperature setting by the driver of the vehicle 100, etc.

The controller 14 is a control unit that performs overall control of each part of the vehicle 100. The controller 14 is composed of one or more computers and is programmed to control each part of the vehicle 100 at a predetermined control cycle. In other words, the controller 14 is a computer that controls the vehicle 100 by executing a pre-stored program. The program for controlling the vehicle 100 may be provided in a form stored on a storage medium such as a CD-ROM, SD card, or hard disk. The program for controlling the vehicle 100 may also be provided via communication with devices external to the vehicle 100 (such as a server or cloud service).

In this embodiment, the controller 14 functions, in particular, as an energy management device that manages the energy balance of the vehicle 100. Specifically, by comprehensively controlling the power generation system 12 and the heater 13, the controller 14 reduces (in particular minimizes) the fuel consumption F when the heater 13 is in use, compared to when simple energy management based on the BSFC map 50 (see Figure 5) is performed.

The controller 14 can appropriately acquire vehicle information necessary for energy management and other control by measurement, calculation, etc. The vehicle information is parameters that indicate the operating state of the vehicle 100 or each part that constitutes the vehicle 100. Specifically, the controller 14 appropriately acquires the vehicle speed V [km/h], the SOC of the battery 11, the engine water temperature T _W , the rotation speed N _G [rpm] and torque T _G [Nm] of the power generation system 12 (engine 16 and/or generator 17), the total heating energy H, etc.

Figure 3 is a block diagram showing the configuration of the controller 14 related to energy management of the vehicle 100. As shown in Figure 3, the controller 14 includes a traveling power consumption estimation unit 21, a heating energy acquisition unit 22, and a power generation control unit 23.

The traveling power consumption estimation unit 21 estimates the traveling power consumption C. The traveling power consumption C is an estimated value for the power consumed by the drive motor 10 when the vehicle 100 is traveling.

The traveling power consumption estimation unit 21 can calculate the traveling power consumption C based on the route along which the vehicle 100 is planned to travel (hereinafter referred to as the traveling route). The traveling route is information related to the route to the destination or intermediate points, as well as the undulations of the route. When the traveling route is preset in a car navigation system (not shown), the traveling power consumption estimation unit 21 acquires the traveling route from the car navigation system.

In this embodiment, in order to perform appropriate energy management even when the driving route is unknown, the driving power consumption estimation unit 21 estimates the driving power consumption C based on the driving history of the vehicle 100. To this end, the driving power consumption estimation unit 21 in this embodiment includes a driving power consumption recording unit 31, an average driving power consumption calculation unit 32, a correction value calculation unit 33, and a driving power consumption calculation unit 34.

The traveling power consumption recording unit 31 records past traveling power consumption C. The traveling power consumption C recorded by the traveling power consumption recording unit 31 is an estimated value of traveling power consumption C, or a measured or calculated value of the power actually consumed by the drive motor 10. In this embodiment, the traveling power consumption recording unit 31 records an estimated value of traveling power consumption C (hereinafter simply referred to as traveling power consumption C).

The traveling power consumption recording unit 31 also records the traveling power consumption C in chronological order. In this embodiment, the traveling power consumption recording unit 31 records the traveling power consumption C over at least a predetermined length of time used by the average traveling power consumption calculation unit 32. Hereinafter, the total traveling power consumption C recorded in chronological order will be referred to as "time series data of traveling power consumption C."

The average traveling power consumption calculation unit 32 calculates the average traveling power consumption based on the time-series data of the traveling power consumption C. Because the traveling power consumption C is time-series data, the average traveling power consumption calculation unit 32 calculates a moving average _MAX of the traveling power consumption C for a predetermined past time X (range) as the average traveling power consumption. For example, a moving average _MA60 for the past one minute or a moving average _MA300 for the past five minutes is calculated and used. In this embodiment, the moving average _MA300 for the past five minutes is calculated and used. However, the average traveling power consumption calculation unit 32 can appropriately set the period for calculating the moving average _MAX (hereinafter referred to as the "moving average range"). The average traveling power consumption calculation unit 32 can also calculate multiple moving averages _MAX with different ranges. The range of the moving average _MAX that is actually used is predetermined based on experiments, simulations, etc. The average traveling power consumption calculation unit 32 can also calculate the moving average _MAX of the traveling power consumption C using a simple moving average, a weighted moving average, or other specific calculation method. In this embodiment, the average traveling power consumption calculation unit 32 calculates the moving average _MAX of the traveling power consumption C by simple moving average (SMA).

The correction value calculation unit 33 calculates a correction value α _SOC [W] based on the SOC of the battery 11. The correction value α _SOC is a correction term for the moving average _MAX and is used when calculating the traveling power consumption C based on the moving average _MAX . In this embodiment, when the SOC of the battery 11 is greater than the median between the power generation on threshold _Th1 and the power generation off threshold _Th2 (hereinafter referred to as the median M _SOC of the predetermined charging range), the correction value α _SOC is set to a negative value. When the SOC of the battery 11 is less than the median M _SOC of the predetermined charging range, the correction value α _SOC is set to a positive value. The magnitude of the correction value α _SOC is set according to the deviation between the SOC and the median M _SOC of the predetermined charging range. That is, the correction value calculation unit 33 calculates the correction value α _SOC according to the following equation (1): The coefficient β in equation (1) is a conversion coefficient for correlating the deviation between the SOC and the median value M _SOC of the predetermined charging range with power [W], and determines the contribution rate of the correction value α _SOC to the traveling power consumption C. The coefficient β is set in advance based on experiments, simulations, etc.

The traveling power consumption calculation unit 34 calculates the traveling power consumption C based on the moving average _MAX of one or more types of traveling power consumption C and a correction value α _SOC corresponding to the SOC for the moving average _MAX . That is, the traveling power consumption calculation unit 34 calculates the traveling power consumption C according to the following equation (2).

For example, when the SOC at the time of calculation is 10% lower than the median value M _SOC of the predetermined charging range, the value obtained by adding 10×β [W] to the moving average _MAX for the past X minutes is estimated to be the traveling power consumption C. On the other hand, when the SOC at the time of calculation is 10% higher than the median value M _SOC of the predetermined charging range, the value obtained by subtracting 10×β [W] from the moving average _MAX for the past X minutes is estimated to be the traveling power consumption C. The traveling power consumption calculation unit 34 inputs the calculated traveling power consumption C to the power generation control unit 23 and the traveling power consumption recording unit 31.

The heating energy acquisition unit 22 acquires (calculates) the total heating energy H based on the room temperature setting by the driver or other person of the vehicle 100. The total heating energy H is input to the power generation control unit 23.

The power generation control unit 23 maintains the engine water temperature T _W within a predetermined temperature range (a temperature range equal to or greater than the power generation on threshold T _W1 and equal to or less than the power generation off threshold T _W2 ) by controlling the power generation system 12 based on the traveling power consumption C and the total heating energy H. Specifically, the power generation control unit 23 determines the operation time of the power generation system 12 (i.e., the time and timing for generating power) and the second heater output P based on the traveling power consumption C and the total heating energy H.

The operating time of the power generation system 12 is expressed as the ratio of the power generation on period t _ON (the length of time power is generated) to the sum (t _ON + t _OFF ) of the power generation off period t _ON (the length of time power is generated) and the power generation on period t _OFF (the length of time power generation is stopped) (hereinafter referred to as the duty ratio), D_HVAC = t _ON / (t _ON + t _OFF ).

In this embodiment, the second heater output P is determined based on the traveling power consumption C, the total heating energy H, and the rotation speed _NG and torque _TG (hereinafter referred to as the operating point) of the power generation system 12. In addition, the duty ratio D_HVAC is determined based on the first heater output T and the operating point of the power generation system 12.

The following describes how to set the duty ratio D_HVAC and second heater output P for energy management in this embodiment.

Because the first heater 18 utilizes the engine coolant temperature T _W , the first heater output T is proportional to the power generation time (duty ratio D_HVAC). More specifically, the product of the duty ratio D_HVAC and the thermal energy E that can be reused for heating by the first heater 18, out of the thermal energy generated by the power generation system 12 (engine 16) through power generation, is balanced with the first heater output T. That is, the duty ratio D_HVAC is expressed by the following equation (3) using the first heater output T and the thermal energy E that can be reused for heating.

Furthermore, the first heater output T is expressed by the following equation (4) using the total heating energy H required by the heater 13 and the second heater output P. Therefore, as shown in the following equation (5), the duty ratio D_HVAC can be calculated using the total heating energy H, the second heater output P, and the thermal energy E that can be reused for heating.

On the other hand, when the power generation amount G of the power generation system 12 and the power consumption C during driving are balanced, the relationship between the duty ratio D_HVAC, the power generation amount G, the second heater output P, and the power consumption C during driving is expressed by the following equation (6).

Therefore, according to equations (5) and (6), the second heater output P can be calculated using equation (7) below based on the traveling power consumption C, total heating energy H, power generation G, and thermal energy E that can be reused for heating. As a result, according to equations (5) and (7), the duty ratio D_HVAC can also be calculated based on the traveling power consumption C, total heating energy H, power generation G, and thermal energy E that can be reused for heating.

In this embodiment, as described above, the traveling power consumption C and the total heating energy H are estimated or acquired, respectively. The power generation amount G and the thermal energy E that can be reused for heating are determined by the operating point of the power generation system 12, and the operating point of the power generation system 12 that is generating power is known.

Therefore, the power generation control unit 23 calculates (determines) the second heater output P according to the operating point of the power generation system 12 based on the traveling power consumption C and the total heating energy H using the above equation (7).

Furthermore, the power generation control unit 23 can determine the duty ratio D_HVAC by theoretical calculation using the above equation (6) based on the power generation amount G corresponding to the operating point of the power generation system 12, the second heater output P, and the traveling power consumption C. However, in this embodiment, the power generation control unit 23 uses a statistical method to calculate (determine) the duty ratio D_HVAC in accordance with the first heater output T and the operating point of the power generation system 12. Note that the first heater output T is determined by the engine coolant temperature T _W , and therefore the first heater output T is known.

As described above, the second heater output P and duty ratio D_HVAC are both determined according to the operating point of the power generation system 12, and the fuel consumption F of the power generation system 12 is determined by the operating point of the power generation system 12. Therefore, the operating point of the power generation system 12 is determined so as to minimize the fuel consumption F according to the traveling power consumption C and the total heating energy H.

Specifically, the power generation control unit 23 includes a fuel consumption map 35. The fuel consumption map 35 is a map that associates the fuel consumption F with the traveling power consumption C, the total heating energy H, and the operating point (rotation speed N _G and torque T _G ) of the power generation system 12. In this embodiment, one or more fuel consumption maps 35 corresponding to combinations of traveling power consumption C and total heating energy H are prepared in advance through experiments, simulations, or the like. Therefore, the power generation control unit 23 determines the operating point of the power generation system 12 at which the fuel consumption F is minimized by referring to a specific fuel consumption map 35 corresponding to the combination of traveling power consumption C and total heating energy H. Then, the power generation control unit 23 determines the second heater output P and the duty ratio D_HVAC based on the operating point of the power generation system 12 determined using the fuel consumption map 35. As a result, the fuel consumption F is minimized while the engine water temperature T _W is maintained within a predetermined temperature range. As a result, the fuel consumption amount F when the heater 13 is used is reduced compared to when simple energy management based on the BSFC map 50 is performed.

The following describes the operation of energy management through power generation control of the vehicle 100 configured as described above.

4 is a flowchart of power generation control. As shown in FIG. 4, in step S101, the traveling power consumption calculation unit 34 estimates the traveling power consumption C. In step S102, the heating energy acquisition unit 22 acquires the total heating energy H. Then, in step S103, the power generation control unit 23 determines the operating point (rotation speed N _G and torque T _G ) of the power generation system 12 at which the fuel consumption F is minimized, using the fuel consumption map 35 corresponding to the traveling power consumption C and the total heating energy H. Also in step S103, the power generation control unit 23 determines the operating point of the power generation system 12 at which the fuel consumption F is minimized and the second heater output P corresponding to that operating point, based on the traveling power consumption C and the total heating energy H.

In step S104, the power generation control unit 23 checks whether the power generation system 12 is stopped, i.e., whether power generation is off. If power generation is off, the process proceeds to step S105. On the other hand, if the power generation system 12 is operating, i.e., if power generation is on, the process proceeds to step S109.

In step S105, the power generation control unit 23 compares the engine water temperature T _W with the power generation-on threshold T _W1 . If the engine water temperature T _W is lower than the power generation-on threshold T _W1 , the process proceeds to step S106, where the power generation control unit 23 compares the SOC of the battery 11 with the allowable value _Th3 . If the SOC is lower than the allowable value _Th3 in step S106 and charging of the battery 11 is allowed, power generation is started (power generation is on) in step S107. That is, when the engine water temperature T _W becomes lower than the power generation-on threshold T _W1 , power generation is started under the conditions of the operating point and second heater output P determined in step S103 in order to maintain the engine water temperature T _W within a predetermined temperature range, as long as charging of the battery 11 is allowed.

On the other hand, if the engine water temperature T _W is equal to or higher than the power generation-on threshold T _W1 in step S105, the process proceeds to step S108, where the power generation control unit 23 compares the SOC of the battery 11 with the power generation-on threshold _Th1 . If the SOC is equal to or lower than the power generation-on threshold _Th1 in step S108, the process proceeds to step S106. If the SOC is lower than the allowable value _Th3 in step S106 and charging of the battery 11 is permitted, power generation is started in step S107. That is, even if the engine water temperature T _W is equal to or higher than the power generation-on threshold T _W1 , if the SOC is lower than the power generation-on threshold _Th1 , power generation is started under the conditions of the operating point and second heater output P determined in step S103 in order to maintain the SOC within the predetermined charging range.

If the SOC is equal to or greater than the power generation on threshold _Th1 in step S108, the process proceeds to step S111. Therefore, power generation is not started. In other words, when it is determined that power generation is unnecessary from the viewpoint of maintaining the engine water temperature T _W and the viewpoint of maintaining the SOC, power generation is not performed.

If the power generation system 12 is already operating in step S104, i.e., if the power generation system 12 is in the power generation on state, the process proceeds to step S109, where the power generation control unit 23 compares the engine water temperature T _W with the power generation off threshold T _W2 . If the engine water temperature T _W is greater than the power generation off threshold T _W2 in step S109, the process proceeds to step S110, where the power generation control unit 23 compares the SOC of the battery 11 with the power generation off threshold _Th2 . If the SOC is greater than the power generation off threshold _Th2 in step S110, the process proceeds to step S111, where the power generation control unit 23 stops power generation by the power generation system 12. In other words, if the power generation system 12 is already in the power generation on state, and the engine water temperature T _W is greater than the power generation off threshold _Th2 and the SOC is also greater than the power generation off threshold _Th2 , power generation is stopped.

On the other hand, even when the power generation is already on, if the engine water temperature T _W is equal to or lower than the power generation off threshold T _W2 in step S109, or if the SOC is equal to or lower than the power generation off threshold _Th2 in step S110, the process proceeds to step S106. If the SOC is lower than the allowable value _Th3 in step S106 and charging of the battery 11 is permitted, the process proceeds to step S107, where power generation is started. In other words, if the power generation is already on, power generation continues under the conditions of the operating point and second heater output P determined in step S103, as long as the engine water temperature T _W and the SOC are maintained within the predetermined charging range and charging of the battery 11 is permitted.

The above power generation control is repeatedly executed at a predetermined control cycle until the vehicle 100 stops traveling.

5 is an explanatory diagram showing operating points of the power generation system 12 based on the BSFC map 50 and the fuel consumption map 35. The BSFC map 50 is a map that determines the break-even specific fuel consumption (BSFC) corresponding to the rotation speed N _G and torque T _G (operating point) of the power generation system 12. Therefore, when selecting an operating point of the power generation system 12 so as to minimize BSFC according to the BSFC map 50, the operating point of the power generation system 12 is determined regardless of the traveling power consumption C or the total heating energy H. Here, when referring to the BSFC map 50, it is assumed that the operating point P1 is selected as the operating point that minimizes BSFC.

In contrast, in this embodiment, the operating point of the power generation system 12 is selected according to a fuel consumption map 35 that corresponds to the driving power consumption C and the total heating energy H. Here, as an example, it is assumed that the driving power consumption C is 2,200 W, which is typical (average) for urban driving, and the total heating energy H is 2,500 W. Then, based on the fuel consumption map 35 that corresponds to these specific driving power consumption C and total heating energy H, the operating point P2 is selected as the operating point that minimizes the fuel consumption F. As shown in FIG. 5, according to the BSFC map 50, the operating point P2 selected by the fuel consumption map 35 that corresponds to the driving power consumption C and the total heating energy H has a large BSFC and is an inefficient operating point from the perspective of BSFC.

FIG. 6 is a graph showing changes in BSFC and fuel consumption F when driving in an urban area. FIG. 6(A) shows the change over time of vehicle speed V [km/h]. FIG. 6(B) shows the change over time of SOC of battery 11. FIG. 6(C) shows the change over time of engine water temperature T _W. FIG. 6(D) shows the change over time of rotation speed _NG of power generation system 12. FIG. 6(E) shows the change over time of torque _TG of power generation system 12. FIG. 6(F) shows the change over time of second heater output P. FIG. 6(G) shows the change over time of BSFC (net fuel consumption rate) when total heating energy H is 2500 W. FIG. 6(H) shows the change over time of fuel consumption F when total heating energy H is 2500 W. 6(B) to 6(H), the solid lines indicate the case where the energy management of this embodiment is performed using power generation control based on the fuel consumption map 35, and the dashed lines indicate the case where the energy management of the comparative example is performed using power generation control based on the BSFC map 50. For comparison, the energy management of the comparative example also maintains the engine water temperature T _W within a predetermined temperature range, as in the case of the energy management of this embodiment.

When vehicle 100 travels in urban areas, it repeatedly starts and stops in a relatively short period of time. As a result, vehicle speed V fluctuates wildly, as shown in Figure 6(A). When traveling in urban areas like this, power consumption C also fluctuates from time to time, but its average value is typically around 2200 W.

In the energy management of the comparative example, when the SOC of the battery 11 is expected to reach the upper limit of the control target (the power generation off threshold _Th2 in this embodiment) as shown by the dashed line in Fig. 6(B), the second heater 19 is operated at maximum output as shown by the dashed line in Fig. 6(F). In other words, in the energy management of the comparative example, when the stored power of the battery 11 is expected to become excessive, the power of the battery 11 is forcibly consumed (wasted or discarded) using the second heater 19.

On the other hand, in the energy management of this embodiment, the second heater 19 is actively used for energy management. That is, as shown by the solid line in Figure 6(F), in the energy management of this embodiment, the second heater 19 is operated at a roughly constant level.

As a result, as shown in Figure 6(G), the BSFC (solid line) obtained by the energy management of this embodiment is almost always greater than the BSFC (dashed line) obtained by the energy management of the comparative example. In other words, the fuel utilization efficiency of the power generation system 12 is better when the energy management of the comparative example is implemented than when the energy management of this embodiment is implemented. This corresponds to the fact that the operating point P2 of the power generation system 12 selected by the energy management of this embodiment is less efficient than the operating point P1 selected according to the BSFC map 50 (see Figure 5).

However, when comparing the fuel consumption F of the present embodiment and the comparative example, as shown in Figure 6(H), the fuel consumption F (solid line) using the energy management of the present embodiment is almost always smaller than the fuel consumption F (dashed line) using the energy management of the comparative example. In other words, while the energy management of the present embodiment reduces the short-term fuel utilization efficiency of the power generation system 12, the long-term or cumulative fuel consumption F is reduced. Therefore, compared to the energy management of the comparative example using the BSFC map 50, the energy management of the present embodiment improves the energy balance of the vehicle 100 when heating is used.

Figure 7 is an explanatory diagram showing the operating point P3 of the power generation system 12 based on the fuel consumption map 35 when the total heating energy H is 4000 W when driving in an urban area. Figure 5 shows the operating point P2 when the total heating energy H is set to 2500 W when driving in an urban area with a driving power consumption C of approximately 2200 W. However, when the total heating energy H becomes 4000 W, as shown in Figure 7, the operating point of the power generation system 12 transitions to operating point P3. On the other hand, when the BSFC map 50 is referenced, even if the total heating energy H changes, the operating point that minimizes BSFC does not change and remains at operating point P1.

Figure 8 is a graph showing the trends in BSFC and fuel consumption F when total heating energy H is 4000 W when driving in an urban area. The parameters shown in Figures 8(A) to 8(H) are the same as those in Figure 6. In addition, in Figures 8(B) to 8(H), the solid lines show the case where energy management of this embodiment is implemented using power generation control based on fuel consumption map 35, and the dashed lines show the case where energy management of the comparative example is implemented using power generation control based on BSFC map 50.

The temporal change in vehicle speed V shown in Figure 8(A) is the same as that shown in Figure 6(A). Therefore, the average driving power consumption C is approximately 2200 W.

In the energy management of the comparative example, when the SOC of the battery 11 is expected to reach the upper limit of the control target (the power generation off threshold Th ₂ in this embodiment) or actually reaches this upper limit, the second heater 19 is operated at maximum output, as shown by the dashed line in FIG. 8(F). However, when the total heating energy H is 4000 W, even though the second heater 19 continues to operate at maximum output, the excess stored power of the battery 11 cannot be consumed. Therefore, as shown by the dashed line in FIG. 8(B), in the energy management of the comparative example, the SOC exceeds the control upper limit. Therefore, when the total heating energy H is set to 4000 W, the energy management of the comparative example is forced to discharge the battery 11 by some other method, such as motoring, or to give up maintaining the engine water temperature T _W. In other words, when the total heating energy H is set to 4000 W, the energy management of the comparative example fails.

On the other hand, in the energy management of this embodiment, as shown in Figure 8 (F), the total heating energy H is set to 4000 W, which causes the second heater output P to increase compared to when the total heating energy H is 2500 W, but the second heater 19 operates at a generally constant level. Furthermore, in the energy management of this embodiment, the operating point P3 of the power generation system 12 is adjusted in accordance with the traveling power consumption C and the total heating energy H, so the SOC of the battery 11 is also maintained within a predetermined temperature range, as shown by the solid line in Figure 8 (B). In other words, the energy management of this embodiment does not break down even when the total heating energy H is set to 4000 W.

Furthermore, as shown in Figure 8(G), the BSFC (solid line) achieved by the energy management of this embodiment is almost always greater than the BSFC (dashed line) achieved by the energy management of the comparative example. However, when comparing the fuel consumption F of this embodiment and the comparative example, as shown in Figure 8(H), the fuel consumption F (solid line) achieved by the energy management of this embodiment is almost always less than the fuel consumption F (dashed line) achieved by the energy management of the comparative example. In other words, even when the total heating energy H is set to 4000 W, the energy management of this embodiment reduces long-term or cumulative fuel consumption F. Therefore, compared to the energy management of the comparative example using the BSFC map 50, the energy management of this embodiment improves the energy balance of the vehicle 100 when heating is used.

As described above, the energy management of this embodiment takes into account the driving power consumption C and the total heating energy H, thereby reducing long-term or cumulative fuel consumption F compared to simple energy management using the BSFC map 50. Furthermore, even if the total heating energy H changes, the energy management of this embodiment does not fail.

Second Embodiment
In the first embodiment, the traveling power consumption C is estimated using the moving average MA ₃₀₀ for the past five minutes, but this is not limiting. The period over which the moving average is calculated, i.e., the range of the moving average _MAX, can be changed. For example, the traveling power consumption C may be estimated by calculating multiple types of moving average _MAX with different ranges from the time-series data of the traveling power consumption C, and then switching between or combining these multiple moving averages _MAX .

FIG. 9 is a graph showing the results of WLTC (Worldwide-harmonized Light vehicles Test Cycle) driving while performing energy management using the power generation control of the first embodiment. That is, FIG. 9 shows the results of WLTC driving when driving power consumption C is estimated using a moving average MA ₃₀₀ for the past five minutes. FIG. 9(A) shows the time progression of vehicle speed V determined in WLTC driving. FIG. 9(B) shows the time progression of SOC. FIG. 9(C) shows the time progression of engine water temperature T _W. FIG. 9(D) shows the time progression of rotation speed _NG of power generation system 12. FIG. 9(E) shows the time progression of torque T _G of power generation system 12. FIG. 9(F) shows the time progression of second heater output P.

Note that section L from the start of driving to time _t1 is a driving section in the so-called low-speed phase (urban mode). Section M from time _t1 to time _t2 is a driving section in the so-called medium-speed phase (suburban mode). Section H from time _t2 to time _t3 is a driving section in the so-called high-speed phase (highway mode). Furthermore, section EX from time _t3 to time _t4 is a driving section in the so-called ultra-high-speed phase.

9B , when the traveling power consumption C is estimated using the moving average MA ₃₀₀ for the past five minutes, the SOC of the battery 11 is generally maintained within the predetermined charge range, which is the control target, in the low-speed phase section L, the medium-speed phase section M, and the high-speed phase section H. However, in the ultra-high-speed phase section EX, the SOC falls below the power generation on threshold _Th1 . In other words, when the traveling power consumption C is continuously estimated using the moving average MA ₃₀₀ for the past five minutes, if the vehicle speed V increases sharply, it may not be possible to maintain the SOC within the predetermined charge range.

10 is a graph showing the relationship between the traveling power consumption C and the moving average MA ₃₀₀ of the traveling power consumption C over the past five minutes. In FIG. 10, the traveling power consumption C is shown by a solid line, and the moving average MA ₃₀₀ over the past five minutes is shown by a dashed line.

As shown in FIG. 10 , in section L of the low speed phase and section M of the medium speed phase, the traveling power consumption C is well represented by the moving average MA ₃₀₀ for the past five minutes. Also, in section H of the high speed phase, the traveling power consumption C is generally well represented by the moving average MA ₃₀₀ for the past five minutes. However, in section EX of the ultra-high speed phase, the deviation between the traveling power consumption C and the moving average MA ₃₀₀ for the past five minutes becomes large. In other words, when the moving average MA ₃₀₀ for the past five minutes is used, the estimation accuracy of the traveling power consumption C decreases in section EX of the ultra-high speed phase. As a result, as described above, in section EX of the ultra-high speed phase, the SOC falls below the power generation on threshold _Th1 .

Therefore, in this embodiment, as described below, multiple types of moving averages with different periods (ranges) for calculating the moving average are used to estimate the traveling power consumption C. Here, a moving average _MA300 for the past five minutes and a moving average _MA60 for the past one minute are used to more appropriately estimate the traveling power consumption C depending on the traveling situation.

Specifically, the traveling power consumption calculation unit 34 calculates the traveling power consumption C according to the following equation (8) using the moving average _MA300 for the past five minutes, the moving average _MA60 for the past minute, and the correction value _αSOC . In equation (8), the coefficient _a1 represents the contribution rate of the moving average _MA300 for the past five minutes to the traveling power consumption C, and the coefficient _a2 represents the contribution rate of the moving average _MA60 for the past minute.

FIG. 11 is a graph showing the relationship between the coefficient _a1 and the coefficient _a2 . In FIG. 11, the solid line indicates the coefficient _a1 , and the dashed line indicates the coefficient _a2 . As shown in FIG. 11, in this embodiment, the traveling power consumption calculation unit 34 sets a first moving average switching threshold _V1 and a second moving average switching threshold _V2 for the SOC of the battery 11. The first moving average switching threshold _V1 and the second moving average switching threshold _V2 are thresholds for determining whether to switch the range of the moving average _MAX used to estimate the traveling power consumption C. The first moving average switching threshold _V1 and the second moving average switching threshold _V2 are both set to values greater than the power generation on threshold _Th1 and less than the power generation off threshold _Th2 . The first moving average switching threshold _V1 is set to a value equal to or greater than the second moving average switching threshold _V2 .

11 , when the SOC of the battery 11 is equal to or greater than the first moving average switching threshold _V1 , the coefficient _a1 is set to 1 and the coefficient _a2 is set to 0. Therefore, when the SOC is equal to or greater than the first moving average switching threshold _V1 , the moving average _MA300 for the past five minutes is essentially used to estimate the traveling power consumption C.

When the SOC of the battery 11 is equal to or lower than the second moving average switching threshold _V2 , the coefficient _a1 is set to "0" and the coefficient _a2 is set to "1." Therefore, when the SOC is equal to or lower than the second moving average switching threshold _V2 , the moving average _MA60 for the past one minute is essentially used to estimate the traveling power consumption C.

When the SOC of the battery 11 is smaller than the first moving average switching threshold _V1 and larger than the second moving average switching threshold _V2 , the coefficients _a1 and _a2 are set according to the SOC. Specifically, the sum of the coefficients _a1 and _a2 is maintained at "1," while the coefficient _a1 is set to increase according to the SOC, and the coefficient _a2 is set to decrease according to the SOC. Therefore, when the SOC is smaller than the first moving average switching threshold _V1 and larger than the second moving average switching threshold _V2 , the moving average _MA300 for the past five minutes and the moving average _MA60 for the past one minute are used to estimate the traveling power consumption C.

In this way, the moving average _MAX used to estimate the traveling power consumption C is calculated for a predetermined time X (range), but in this embodiment, as a general rule, the lower the SOC (charge rate), the shorter the predetermined time X (range). Also, in this embodiment, multiple moving averages _MAX with different predetermined times X (range) are calculated, and the lower the SOC, the moving average _MAX used to estimate the traveling power consumption C is switched to a moving average _MAX with a longer predetermined time X (range).

Fig. 12 is a graph showing the results of WLTC driving while performing energy management using power generation control according to the second embodiment. That is, Fig. 12 shows the results of WLTC driving when the range of the moving average _MAX used to estimate the driving power consumption C is shortened or extended depending on the SOC of the battery 11. In the WLTC driving shown in Fig. 12, as an example, the moving average _MAX used to estimate the driving power consumption C is switched between a moving average MA of ₃₀₀ for the past five minutes and a moving average MA of ₆₀ for the past one minute depending on the SOC, as shown in equation (8) and Fig. 11.

Fig. 12(A) shows the time progression of vehicle speed V determined in WLCT driving. Fig. 12(B) shows the time progression of SOC. Fig. 12(C) shows the time progression of engine water temperature T _W. Fig. 12(D) shows the time progression of rotation speed _NG of power generation system 12. Fig. 12(E) shows the time progression of torque T _G of power generation system 12. Fig. 12(F) shows the time progression of second heater output P.

When the traveling power consumption C is estimated using the moving average _MA300 for the past five minutes and/or the moving average _MA60 for the past one minute according to the SOC, as shown in FIG. 12(B), the SOC of the battery ₁₁ is generally maintained within the predetermined charge range, which is the control target, in the low-speed phase section L, the medium-speed phase section M, and the high-speed phase section H, as in the case of estimating the traveling power consumption C using the moving average MA300 for the past five minutes (see FIG. 9(B)). Furthermore, the SOC is maintained at or above the power generation on threshold _Th1 even in the ultra-high-speed phase section EX. In other words, when the traveling power consumption C is estimated using the moving average _MA300 for the past five minutes and the moving average _MA60 for the past one minute as appropriate, the SOC is maintained within the predetermined charge range even if the vehicle speed V increases sharply.

13 is a graph showing the traveling power consumption C, the moving average _MA300 of the traveling power consumption C over the past five minutes, and the moving average _MA60 of the traveling power consumption C over the past minute. As shown in FIG. 13 , when the range of the moving average _MAX used to estimate the traveling power consumption C is shortened or extended depending on the SOC of the battery 11, in section L of the low-speed phase where the traveling power consumption C is relatively small, the traveling power consumption C is well represented by the moving average _MA300 over the past five minutes. In section M of the medium-speed phase where the traveling power consumption C is medium, the traveling power consumption C is roughly an intermediate value between the moving average _MA300 over the past five minutes and the moving average _MA60 over the past minute. Furthermore, in section H of the high-speed phase and section EX of the ultra-high-speed phase where the traveling power consumption C is relatively large, the traveling power consumption C is well represented by the moving average _MA60 over the past minute. Therefore, as shown in equation (8) and FIG. 11 , by adjusting the range of the moving average MAX used to estimate the traveling power consumption C using, for example, the moving average MA ₃₀₀ for the past five minutes and the moving average MA ₆₀ for the past one minute depending on the SOC, it is possible to perform energy management to minimize the _fuel consumption F when the heater 13 is used while maintaining the SOC within a predetermined charging range even in traveling situations where the SOC changes significantly, such as when the vehicle speed V increases sharply.

[Third embodiment]
In the first and second embodiments described above, the power generation control unit 23 stores the fuel consumption map 35 in advance and refers to it to determine an operating point of the power generation system 12 that reduces (minimizes) the fuel consumption F when the heater 13 is in use. However, the power generation control unit 23 can be configured to determine (calculate) an operating point that reduces (minimizes) the fuel consumption F when the heater 13 is in use in real time while the vehicle 100 is traveling. In this embodiment, a control configuration will be described for determining an operating point that reduces the fuel consumption F when the heater 13 is in use in real time while the vehicle 100 is traveling.

Figure 14 is a flowchart related to determining the operating point and second heater output P of the power generation system 12 in real time. As shown in Figure 14, in step S201, the traveling power consumption calculation unit 34 estimates the traveling power consumption C. In step S202, the heating energy acquisition unit 22 acquires the total heating energy H.

In step S203, the power generation control unit 23 selects one operating point (revolutions per minute N _G and torque T _G ) that the power generation system 12 can take, to be used in the subsequent calculation.

In step S204, the power generation control unit 23 calculates the first heater output T based on the traveling power consumption C, the total heating energy H, and the selected operating point of the power generation system 12. That is, the power generation control unit 23 calculates the first heater output T based on equation (7). At this time, the power generation amount G and thermal energy E are calculated based on the selected operating point of the power generation system 12.

In step S205, the power generation control unit 23 calculates the second heater output P using the total heating energy H and the first heater output T. That is, the power generation control unit 23 calculates the second heater output P according to equation (4).

In step S206, the power generation control unit 23 calculates the duty ratio D_HVAC based on the first heater output T and the selected operating point of the power generation system 12. Note that the power generation control unit 23 may also calculate the duty ratio D_HVAC based on the total heating energy H, the second heater output P (or the first heater output T), and the selected operating point of the power generation system 12. That is, the power generation control unit 23 may calculate the duty ratio D_HVAC according to equation (5).

In step S207, the power generation control unit 23 calculates the operating time of the power generation system 12 required to maintain the SOC (hereinafter referred to as the duty ratio D_SOC). The duty ratio D_SOC is the ratio of the traveling power consumption C to the power generation amount G. In other words, D_SOC = C/G. Therefore, the power generation control unit 23 calculates the duty ratio D_SOC based on the traveling power consumption C and the selected operating point of the power generation system 12.

In step S208, the power generation control unit 23 determines the final duty ratio (hereinafter referred to as the final duty ratio D) using the duty ratio D_HVAC calculated in step S206 and the duty ratio D_SOC calculated in step S207. In this embodiment, the power generation control unit 23 sets the larger of the duty ratio D_HVAC and the duty ratio D_SOC as the final duty ratio D. In other words, the power generation control unit 23 determines the final duty ratio D according to the following equation (9):

In step S209, the power generation control unit 23 determines whether the final duty ratio D is less than "1". That is, the power generation control unit 23 checks whether the final duty ratio D is a value that can be realized. If D<1 in step S209, the process proceeds to step S210. On the other hand, if D≧1 in step S209, the power generation control unit 23 determines that the operating point selected for the calculation in step S203 cannot be realized, and returns to step S203 to redo the calculation from the selection of the operating point of the power generation system 12.

In step S210, the power generation control unit 23 calculates the fuel consumption amount F based on the final duty ratio D determined in step S208, the power generation amount G determined by the selected operating point, and the BSFC determined by the selected operating point. Specifically, the power generation control unit 23 calculates the fuel consumption amount F by multiplying the final duty ratio D, the power generation amount G, and the BSFC. That is, the power generation control unit 23 calculates the fuel consumption amount F according to the following equation (10):

In step S211, the power generation control unit 23 checks whether or not the calculation of fuel consumption F has been completed for selectable operating points (combinations of rotation speed N _G and torque T _G ). If there are any operating points that have not yet been calculated, the process returns to step S203, where the power generation control unit 23 changes the operating point selected for calculation and calculates fuel consumption F. When the calculation of fuel consumption F for selectable operating points has been completed, that is, when the fuel consumption map 35 according to the driving state has been completed, the process proceeds to step S212.

In step S212, the power generation control unit 23 selects an operating point and second heater output P that minimizes fuel consumption F based on the combination of the operating point and second heater output P of the power generation system 12 and the fuel consumption F. Then, in step S213, the power generation control unit 23 executes power generation control using the operating point and second heater output P that minimizes fuel consumption F.

[Modification]
In the first, second, and third embodiments, the operating point of the power generation system 12 can be arbitrarily selected. However, due to noise, vibration (so-called acoustic vibration), and other issues, the selectable operating point may change depending on the driving scene, the operating state of the vehicle 100, and the like. For example, when the heater 13 is in use, the heater 13 generates noise, etc., and therefore the demand for noise and vibration reduction for the power generation system 12 is lower than when the heater 13 is not in use. Therefore, when the heater 13 is in use, the range of operating points that the power generation system 12 can take may be wider than when the heater 13 is not in use. The same applies to driving scenes with high driving noise. Therefore, when the operating points that the power generation system 12 can take are set within a predetermined range depending on the operating state or driving scene of the vehicle 100, the power generation control unit 23 determines the operating point of the power generation system 12 within that predetermined range.

In the first and second embodiments, when using the fuel consumption map 35 to determine the operating point of the power generation system 12 at which fuel consumption F is minimized, it is preferable to use a gradient method such as steepest descent to reduce the amount of calculations. The power generation control unit 23, for example, searches for an operating point in a direction that reduces fuel consumption F from operating point P1 determined by the BSFC map 50, and can determine the operating point at which fuel consumption F no longer decreases as the operating point of the power generation system 12. Furthermore, in the third embodiment, the fuel consumption map 35 is essentially created in real time, but to reduce the amount of calculations, it is preferable to use a gradient method to create the fuel consumption map 35 and search for an operating point at which fuel consumption F is reduced. The power generation control unit 23, for example, creates the fuel consumption map 35 in a direction that reduces fuel consumption F from operating point P1 determined by the BSFC map 50, and can determine the operating point at which fuel consumption F no longer decreases as the operating point of the power generation system 12.

In the first, second, and third embodiments, the moving average _MAX is used to estimate the traveling power consumption C. However, it is preferable that the moving average _MAX used to estimate the traveling power consumption C be reset as appropriate in response to changes in the traveling situation, etc. For example, the power generation control unit 23 sets a predetermined threshold value (hereinafter referred to as the speed threshold _ThV ) for the vehicle speed V, and can reset the moving average MAX used to estimate the traveling power consumption C when the vehicle speed _V exceeds this speed threshold ThV or when the vehicle speed _V becomes equal to or less than the speed threshold _ThV . The speed threshold _ThV is determined in advance based on experiments, simulations, etc., and is, for example, 70 km/h. Resetting the moving average _MAX means limiting the base end of the range in which the moving average _MAX is taken to a specific point (the point at which the vehicle speed V exceeds the speed threshold _ThV ) or thereafter.

When the vehicle speed V changes from a value equal to or less than the speed threshold _ThV to a value equal to or less than the speed threshold _ThV , it can be determined that the vehicle 100 is likely to have entered an expressway. Conversely, when the vehicle speed _V changes from a value equal to or greater than the speed threshold _ThV to a value equal to or less than the speed threshold ThV, it can be determined that the vehicle 100 is likely to have entered an urban area from an expressway. Furthermore, since the traveling speed of the vehicle 100 typically differs between expressways and urban areas, the trends in traveling power consumption C also differ. For this reason, the trends in traveling power consumption C before the vehicle speed V crosses the speed threshold _ThV may not correlate with the subsequent traveling power consumption C. In other words, the moving average _MAX may not be useful for estimating the traveling power consumption C before and after the vehicle speed _V crosses the speed threshold _ThV . Therefore, as described above, it is preferable to reset the moving average _MAX used to estimate the traveling power consumption C when the vehicle speed V exceeds the speed threshold _ThV or when the vehicle speed V becomes equal to or less than the speed threshold ThV. This improves the estimation accuracy of the traveling power consumption C. As a result, the accuracy of the energy management according to each of the above embodiments is improved.

As described above, the energy management methods according to the above embodiments and modifications are energy management methods for a vehicle 100 that includes a battery 11 that supplies power to a drive motor 10, a power generation system 12 that uses fuel to generate power to be stored in the battery 11, and a heater 13. In this energy management method, the driving power consumption C, which is the power consumed by the drive motor 10 when the vehicle 100 is driven, is estimated. Also, heating energy (total heating energy H) corresponding to the output required of the heater 13 is obtained. Then, the operating point (N _G , T _G ) of the power generation system 12 is determined based on the driving power consumption C and the heating energy (total heating energy H).

As described above, when the vehicle 100 is equipped with a power generation system 12 and a heater 13, determining the operating point of the power generation system 12 based on the traveling power consumption C and the total heating energy H reduces the short-term fuel efficiency (BSFC) of the power generation system 12. However, determining the operating point of the power generation system 12 based on the traveling power consumption C and the total heating energy H reduces opportunities for the radiator to discard thermal energy generated by the power generation system 12 and for discarding power from the battery 11 by motoring the engine 16. As a result, the long-term or cumulative fuel consumption F of the power generation system 12 is reduced compared to when the operating point of the power generation system 12 is determined based on the BSFC map 50. In other words, according to the energy management methods of the above-described embodiments and modifications, the energy generated by the power generation system 12 can be used more efficiently than when simple energy management based on the BSFC map 50 is performed, improving the energy balance of the vehicle 100 as a whole and thereby reducing the fuel consumption F of the power generation system 12.

In the energy management methods according to the above embodiments and modifications, the heater 13 includes a first heater 18 that performs heating using heat generated by the power generation system 12. The temperature of the power generation system 12 (engine water temperature T _W ) is controlled within a predetermined temperature range (T _W1 ≦ T _W ≦ T _W2 ). By controlling the engine water temperature T _W within the predetermined temperature range (T _W1 ≦ T _W ≦ T _W2 ), at least the output of the first heater 18 (first heater output T) of the total heating energy H varies within a corresponding range. In other words, the first heater output T does not fluctuate without limit, but the range of fluctuation of the first heater output T (and thus the total heating energy H) is limited. This makes it particularly easy to determine an operating point of the power generation system 12 that reduces fuel consumption F based on the traveling power consumption C and the total heating energy H. As a result, the fuel consumption F of the power generation system 12 is particularly likely to be reduced.

In the energy management methods according to the above embodiments and variations, the heater 13 includes a second heater 19 that provides heating using power from the battery 11. The operating point of the power generation system 12 and the output of the second heater 19 (second heater output P) are determined based on the driving power consumption C and the heating energy (total heating energy H). In this way, when the heater 13 includes the electrically powered second heater 19, determining not only the operating point of the power generation system 12 but also the output of the second heater 19 based on the driving power consumption C and the total heating energy H and actively utilizing the second heater 19 for energy management particularly facilitates reducing fuel consumption F in the power generation system 12. In particular, when driving in urban areas, for example, in driving situations where stop-and-go driving is repeated at a vehicle speed V of 50 km/h or less, utilizing the second heater 19 as described above facilitates maintaining the SOC of the battery 11.

In the energy management method according to the above-described modified example, the operating point of the power generation system 12 is determined within a predetermined range that is determined in advance depending on the operating state or driving scene of the vehicle 100. In other words, if there are restrictions on the operating points that the power generation system 12 can take, such as to suppress noise and vibration, the operating point is determined within the range of those restrictions. Therefore, an appropriate operating point that also addresses restrictions such as noise and vibration is selected. In particular, when the heater 13 is used or in driving scenes with high driving noise, the range of operating points that the power generation system 12 can take may be expanded. Therefore, by utilizing operating points within such an expanded range, the fuel consumption F of the power generation system 12 is particularly likely to be reduced.

In the energy management methods according to the first embodiment and each of the modifications described above, the operating point of the power generation system 12 is determined based on a fuel consumption map 35 that pre-associates the traveling power consumption C, heating energy (total heating energy H), and operating point with fuel consumption F. In this way, by preparing the fuel consumption map 35 in advance, it becomes easier to search for the optimal operating point of the power generation system 12 that reduces fuel consumption F. In other words, the amount of calculation required to determine the operating point of the power generation system 12 is reduced.

In the energy management method according to the above modification, the operating point of the power generation system 12 that minimizes fuel consumption F is determined (searched) using the gradient method. In this way, by using the gradient method to determine the operating point of the power generation system 12 that minimizes fuel consumption F, the amount of calculation required to determine the operating point of the power generation system 12 is reduced. In particular, when traveling in urban areas, for example, in driving situations where stop-and-go driving is repeated at a vehicle speed V of 50 km/h or less, the operating point of the power generation system 12 that minimizes fuel consumption F is determined quickly and accurately, making it easier to maintain the SOC of the battery 11.

In the energy management methods according to the above-described embodiments and modifications, time-series data of the traveling power consumption C is recorded, and a moving average _MAX of the traveling power consumption C is calculated based on the time-series data. Then, the traveling power consumption C is estimated based on the moving average _MAX . When the traveling power consumption C is estimated using the moving average _MAX in this way, even when the driver of the vehicle 100 does not register a traveling route in a car navigation system or the like, it is possible to accurately estimate the traveling power consumption C and determine an operating point of the power generation system 12 at which the fuel consumption F is reduced.

In the energy management methods according to the above-described embodiments and modifications, the traveling power consumption C is calculated by adding the moving average _MAX and a correction value α _SOC corresponding to the state of charge (SOC) of the battery 11. When the state of charge (SOC) is higher than a predetermined reference value (median value M _SOC ), the correction value α _SOC is set to a negative value. When the state of charge (SOC) is lower than the reference value (median value M _SOC ), the correction value α _SOC is set to a positive value. In this way, when the traveling power consumption C is estimated by correcting the moving average _MAX based on the SOC of the battery 11, the SOC is likely to be maintained within a predetermined charging range. In other words, the SOC is particularly likely to be stable.

In particular, in the energy management method according to the second embodiment, the moving average _MAX is calculated for a predetermined time X, and the lower the state of charge (SOC) of the battery 11, the shorter the predetermined time X. In this way, by changing the range of the moving average _MAX used to estimate the traveling power consumption C according to the SOC, the SOC is more likely to be maintained within the predetermined charging range even in situations where the traveling power consumption C rises suddenly, such as when switching from an ordinary road to an expressway.

In the energy management method according to the above-described modified example, the moving average MAX is reset when the speed of the vehicle 100 (vehicle speed V) exceeds a predetermined threshold (speed threshold Th _V ) or when the speed of the vehicle 100 (vehicle speed V) becomes equal to or less than the threshold (speed threshold Th _V ). In this way, by appropriately resetting the moving average _MAX in response to changes in the driving scene, etc., the estimation accuracy of the driving power consumption C is improved. As a result, the accuracy of the energy management according to each of _the above-described embodiments is improved.

The energy management device (controller 14) in each of the above embodiments and variations is an energy management device for a vehicle 100 having a battery 11 that supplies power to the drive motor 10, a power generation system 12 that uses fuel to generate power to store in the battery 11, and a heater 13. This energy management device (controller 14) is configured to include a driving power consumption estimation unit 21 that estimates driving power consumption C, which is the power consumed by the drive motor 10 when the vehicle 100 is driving, a heating energy acquisition unit 22 that acquires heating energy (total heating energy H) corresponding to the output required of the heater 13, and a power generation control unit 23 that determines the operating point of the power generation system 12 based on the driving power consumption C and the heating energy (total heating energy H).

This energy management device (controller 14) reduces opportunities for the radiator to discard thermal energy generated by the power generation system 12 and for the motoring of the engine 16 to discard power from the battery 11. As a result, the long-term or cumulative fuel consumption F of the power generation system 12 is reduced compared to when the operating point of the power generation system 12 is determined based on the BSFC map 50. In other words, the energy generated by the power generation system 12 can be used more efficiently than when simple energy management based on the BSFC map 50 is performed, improving the energy balance of the vehicle 100 as a whole, thereby reducing the fuel consumption F of the power generation system 12.

The energy management program for each of the above embodiments and variations is executed by a computer (controller 14) that controls a vehicle 100 having a battery 11 that supplies power to the drive motor 10, a power generation system 12 that uses fuel to generate power to store in the battery 11, and a heater 13. This program causes the computer (controller 14) to function as a driving power consumption estimation unit 21 that estimates driving power consumption C, which is the power consumed by the drive motor 10 while the vehicle 100 is driving; a heating energy acquisition unit 22 that acquires heating energy (total heating energy H) corresponding to the output required of the heater 13; and a power generation control unit 23 that determines the operating point of the power generation system 12 based on the driving power consumption C and the heating energy (total heating energy H). In other words, this program causes the computer (controller 14) to function as an energy management device for each of the above embodiments and variations. This program may also be provided in a form stored on a storage medium.

The above describes embodiments and variations of the present invention, but the configurations described in the above embodiments and variations merely represent some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

For example, in each of the above embodiments and modifications, the vehicle 100 is equipped with a second heater 19, but the second heater 19 can be omitted. In this case, too, the above-described energy management method and energy management device can reduce the fuel consumption F in the power generation system 12. Furthermore, the various specific calculation methods shown in each of the above embodiments and modifications are merely examples, and can be changed or adjusted as appropriate depending on the specific configuration of the vehicle 100, the intended driving situation, etc.

10: Drive motor, 11: Battery, 12: Power generation system, 13: Heater, 14: Controller, 16: Engine, 17: Generator, 18: First heater, 19: Second heater, 21: Traveling power consumption estimation unit, 22: Heating energy acquisition unit, 23: Power generation control unit, 31: Traveling power consumption recording unit, 32: Average traveling power consumption calculation unit, 33: Correction value calculation unit, 34: Traveling power consumption calculation unit, 35: Fuel consumption map, 50: BSFC map, 100: Vehicle

Claims (17)

An energy management method for a vehicle including a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater, comprising:
Estimating driving power consumption, which is the power consumed by the drive motor when the vehicle is traveling;
Obtaining heating energy corresponding to the output required for the heater;
determining an operating point of the power generation system based on the traveling power consumption and the heating energy ;
Recording time series data of the traveling power consumption,
Calculating a moving average of the traveling power consumption based on the time series data;
Estimating the traveling power consumption based on the moving average;
The traveling power consumption is calculated by adding the moving average and a correction value according to the charging rate of the battery,
If the charging rate is higher than a predetermined reference value, the correction value is set to a negative value;
If the charging rate is lower than the reference value, the correction value is set to a positive value.
Energy management methods. An energy management method for a vehicle including a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater, comprising:
Estimating driving power consumption, which is the power consumed by the drive motor when the vehicle is traveling;
Obtaining heating energy corresponding to the output required for the heater;
determining an operating point of the power generation system based on the traveling power consumption and the heating energy ;
Recording time series data of the traveling power consumption,
Calculating a moving average of the traveling power consumption based on the time series data;
Estimating the traveling power consumption based on the moving average;
The moving average is calculated for a predetermined time period,
The lower the charging rate of the battery, the shorter the predetermined time period.
Energy management methods. An energy management method for a vehicle including a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater, comprising:
Estimating driving power consumption, which is the power consumed by the drive motor when the vehicle is traveling;
Obtaining heating energy corresponding to the output required for the heater;
determining an operating point of the power generation system based on the traveling power consumption and the heating energy ;
Recording time series data of the traveling power consumption,
Calculating a moving average of the traveling power consumption based on the time series data;
Estimating the traveling power consumption based on the moving average;
resetting the moving average when the speed of the vehicle exceeds a predetermined threshold or when the speed of the vehicle becomes equal to or less than the threshold;
Energy management methods. The energy management method according to any one of claims 1 to 3 ,
the heater includes a first heater that performs heating using heat generated by the power generation system,
controlling the temperature of the power generation system within a predetermined temperature range;
Energy management methods. The energy management method according to any one of claims 1 to 3 ,
the heater includes a second heater that uses power from the battery to provide heating;
determining the operating point of the power generation system and the output of the second heater based on the traveling power consumption and the heating energy;
Energy management methods. The energy management method according to any one of claims 1 to 3 ,
The driving point is determined within a predetermined range that is determined in advance depending on the operating state or driving scene of the vehicle.
Energy management methods. The energy management method according to any one of claims 1 to 3 ,
The operating point is determined based on the traveling power consumption, the heating energy, and a fuel consumption map in which the operating point and the fuel consumption are previously associated with each other.
Energy management methods. The energy management method according to any one of claims 1 to 3 ,
determining the operating point at which fuel consumption is minimized by a gradient method;
Energy management methods. An energy management device for a vehicle having a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater,
a running power consumption estimation unit that estimates running power consumption, which is power consumed by the drive motor when the vehicle is running;
a heating energy acquisition unit that acquires heating energy corresponding to an output required for the heater;
a power generation control unit that determines an operating point of the power generation system based on the traveling power consumption and the heating energy;
a traveling power consumption estimation unit that records time series data of the traveling power consumption, calculates a moving average of the traveling power consumption based on the time series data, and estimates the traveling power consumption based on the moving average;
Equipped with
The traveling power consumption estimation unit
The traveling power consumption is calculated by adding the moving average and a correction value according to the charging rate of the battery,
If the charging rate is higher than a predetermined reference value, the correction value is set to a negative value;
If the charging rate is lower than the reference value, the correction value is set to a positive value.
Energy management device. An energy management device for a vehicle having a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater,
a running power consumption estimation unit that estimates running power consumption, which is power consumed by the drive motor when the vehicle is running;
a heating energy acquisition unit that acquires heating energy corresponding to an output required for the heater;
a power generation control unit that determines an operating point of the power generation system based on the traveling power consumption and the heating energy;
a traveling power consumption estimation unit that records time series data of the traveling power consumption, calculates a moving average of the traveling power consumption based on the time series data, and estimates the traveling power consumption based on the moving average;
Equipped with
The traveling power consumption estimation unit
calculating the moving average for a predetermined time period;
The lower the charging rate of the battery, the shorter the predetermined time period.
Energy management device. An energy management device for a vehicle having a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater,
a running power consumption estimation unit that estimates running power consumption, which is power consumed by the drive motor when the vehicle is running;
a heating energy acquisition unit that acquires heating energy corresponding to an output required for the heater;
a power generation control unit that determines an operating point of the power generation system based on the traveling power consumption and the heating energy;
a traveling power consumption estimation unit that records time series data of the traveling power consumption, calculates a moving average of the traveling power consumption based on the time series data, and estimates the traveling power consumption based on the moving average;
Equipped with
the traveling power consumption estimation unit resets the moving average when the speed of the vehicle exceeds a predetermined threshold or when the speed of the vehicle becomes equal to or less than the threshold.
Energy management device. A program executed by a computer that controls a vehicle including a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater, the program comprising:
The computer is caused to function as a traveling power consumption estimation unit that estimates traveling power consumption, which is the power consumed in the drive motor by traveling of the vehicle, a heating energy acquisition unit that acquires heating energy corresponding to the output required of the heater , a power generation control unit that determines an operating point of the power generation system based on the traveling power consumption and the heating energy , and a traveling power consumption estimation unit that records time series data of the traveling power consumption, calculates a moving average of the traveling power consumption based on the time series data, and estimates the traveling power consumption based on the moving average ,
The traveling power consumption estimation unit,
The traveling power consumption is calculated by adding the moving average and a correction value according to the charging rate of the battery,
If the charging rate is higher than a predetermined reference value, the correction value is set to a negative value;
If the charging rate is lower than the reference value, the correction value is set to a positive value.
The program functions as follows . A program executed by a computer that controls a vehicle including a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater, the program comprising:
The computer is caused to function as a traveling power consumption estimation unit that estimates traveling power consumption, which is the power consumed in the drive motor by traveling of the vehicle, a heating energy acquisition unit that acquires heating energy corresponding to the output required of the heater , a power generation control unit that determines an operating point of the power generation system based on the traveling power consumption and the heating energy , and a traveling power consumption estimation unit that records time series data of the traveling power consumption, calculates a moving average of the traveling power consumption based on the time series data, and estimates the traveling power consumption based on the moving average ,
The traveling power consumption estimation unit,
calculating the moving average for a predetermined time period;
The lower the charging rate of the battery, the shorter the predetermined time period.
The program functions as follows . A program executed by a computer that controls a vehicle including a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater, the program comprising:
The computer is caused to function as a traveling power consumption estimation unit that estimates traveling power consumption, which is the power consumed in the drive motor by traveling of the vehicle, a heating energy acquisition unit that acquires heating energy corresponding to the output required of the heater , a power generation control unit that determines an operating point of the power generation system based on the traveling power consumption and the heating energy , and a traveling power consumption estimation unit that records time series data of the traveling power consumption, calculates a moving average of the traveling power consumption based on the time series data, and estimates the traveling power consumption based on the moving average ,
a program causing the traveling power consumption estimation unit to function to reset the moving average when the speed of the vehicle exceeds a predetermined threshold or when the speed of the vehicle becomes equal to or less than the threshold . A storage medium storing a program executed by a computer that controls a vehicle including a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater,
a power generation control unit that determines an operating point of the power generation system based on the driving power consumption and the heating energy; and a driving power consumption estimating unit that records time series data of the driving power consumption, calculates a moving average of the driving power consumption based on the time series data, and estimates the driving power consumption based on the moving average; and a storage medium that stores the program that causes the computer to function as a driving power consumption estimating unit that calculates the driving power consumption by adding the moving average and a correction value corresponding to the charging rate of the battery, and sets the correction value to a negative value if the charging rate is higher than a predetermined reference value, and sets the correction value to a positive value if the charging rate is lower than the reference value . A storage medium storing a program executed by a computer that controls a vehicle including a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater,
a power generation control unit that determines an operating point of the power generation system based on the driving power consumption and the heating energy; and a storage medium that stores the program that causes the computer to function as a driving power consumption estimation unit that records time series data of the driving power consumption, calculates a moving average of the driving power consumption based on the time series data, and estimates the driving power consumption based on the moving average, and causes the driving power consumption estimation unit to calculate the moving average for a predetermined time period and reduce the predetermined time period as the battery's charging rate becomes lower . A storage medium storing a program executed by a computer that controls a vehicle including a battery that supplies power to a drive motor, a power generation system that generates power using fuel to be stored in the battery, and a heater,
a power generation control unit that determines the operating point of the power generation system based on the power consumption and the heating energy; and a power generation control unit that records time series data of the power consumption , calculates a moving average of the power consumption based on the time series data, and estimates the power consumption based on the moving average. A storage medium that stores the program causing the computer to function as a power consumption estimation unit that estimates power consumption, which is the power consumed in the drive motor when the vehicle is traveling; a heating energy acquisition unit that acquires heating energy corresponding to the output required of the heater; a power generation control unit that determines the operating point of the power generation system based on the power consumption and the heating energy ; and a power consumption estimation unit that records time series data of the power consumption, calculates a moving average of the power consumption, and estimates the power consumption based on the moving average; and causes the power consumption estimation unit to reset the moving average when the speed of the vehicle exceeds a predetermined threshold or when the speed of the vehicle becomes equal to or less than the threshold .