JP7196527B2 - Mileage calculation method and mileage calculation device for hybrid vehicle - Google Patents

Description

The present invention relates to calculation of the travelable distance of a so-called series hybrid vehicle that supplies a load with power from a battery and power generated by a generator.

Conventionally, there has been known a hybrid vehicle in which an electric vehicle that runs by driving a motor as a load with electric power from a battery is added with a generator that charges the battery or directly supplies power to the motor as a so-called range extender. there is Patent Literature 1 discloses a series hybrid vehicle in which a generator is driven by an internal combustion engine. Further, in the above document, the distance that can be traveled is calculated based on the current remaining charge of the battery, and the electric power obtained by generating power by using all the remaining fuel in the fuel tank to drive the internal combustion engine. A value added to the calculated travelable distance is taken as a total travelable distance.

JP 2012-101616 A

By the way, in a series hybrid vehicle, when the electric power of the battery runs out, the electric power generated by the generator directly drives the motor. Therefore, if the power output of the generator is smaller than the required running output, and the battery runs out of power, even if there is fuel remaining to drive the generator, it will not be possible to run according to the driver's request. . On the other hand, if the power output of the generator is greater than the required travel output, the battery can be charged with surplus power during travel.

However, in the calculation of the total travelable distance in the above document, the travelable distance based on the remaining amount of fuel at the time of calculation and the travelable distance based on the remaining charge of the battery at the time of calculation are simply added. Therefore, the difference between the calculated total possible traveling distance and the actual total possible traveling distance increases depending on the amount of power actually consumed during traveling after the calculation.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a technique for calculating an actual travelable distance with higher accuracy.

According to one aspect of the present invention, there is provided a mileage calculation method for a hybrid vehicle that supplies electric power of a battery and electric power generated by a generator to a load. In this mileage calculation method, the presence or absence of a chargeable section, which is a section in which charging by the generator is possible while driving, is determined. The amount of charge increase is calculated, which is the amount of electric power to be used, and the amount of charge increase is added to the current remaining charge of the battery to calculate the total battery charge. The total possible driving distance is calculated based on the battery charge amount and .

According to the above aspect, since the charge amount of the battery, which is one of the parameters used for calculating the total travel distance, is calculated based on the determination result of whether or not there is a chargeable section, only the remaining charge amount of the battery at the present time is calculated. The accuracy of the calculation result is higher than when calculating the total travel distance as a parameter.

FIG. 1 is a system configuration diagram of a hybrid vehicle. FIG. 2A is a first diagram for explaining types of power supply from a fuel cell system to an external load. FIG. 2B is a second diagram for explaining the type of power supply from the fuel cell system to the external load. FIG. 2C is a third diagram illustrating the type of power supply from the fuel cell system to the external load. FIG. 2D is a fourth diagram illustrating the type of power supply from the fuel cell system to the external load. FIG. 3 is a diagram for explaining the relationship between the required output and the total travelable distance. FIG. 4 is a flow chart showing a control routine for calculating the total traveled distance. FIG. 5 is a flow chart showing a control routine for calculating the first travelable distance. FIG. 6 is a timing chart showing an example of running patterns. FIG. 7 is a table summarizing the relationship between the vehicle speed and the required vehicle output at the vehicle speed. FIG. 8 is a table summarizing the battery capacity, the maximum generated power of the fuel cell stack, the battery SOC, and the travelable distance at that SOC. FIG. 9 is a table summarizing trial calculation results of the possible travel distance with the amount of charge increase in the chargeable section. FIG. 10 is a flow chart showing a control routine according to the second embodiment for calculating the charge increment. FIG. 11 is a flow chart showing a first modification of the control routine for calculating the first travelable distance. FIG. 12 is a flow chart showing a second modification of the control routine for calculating the first travelable distance.

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

(First embodiment)
FIG. 1 is a system configuration diagram of a hybrid vehicle to which the first embodiment of the invention is applied. This hybrid vehicle is a so-called series hybrid vehicle that runs by supplying power from a battery and power generated by a generator to a drive motor 1 as a load.

This hybrid vehicle includes an external load 100 consisting of a drive motor 1 and a battery 2 , a fuel cell system 200 as a generator, and a controller 8 .

The fuel cell system 200 includes a fuel cell stack 3, a compressor 6 that supplies cathode gas to the fuel cell stack 3, a fuel tank 7 that stores fuel to be supplied to the fuel cell stack 3, and power generated by the fuel cell stack 3. and a DC-DC converter 4 that boosts the voltage.

The fuel cell stack 3 is a solid oxide fuel cell (SOFC).

The fuel tank 7 stores reforming fuel, which is a liquid mixture of, for example, ethanol and water. The fuel cell system 200 in FIG. 1 is simplified by omitting the reformer, fuel pump, evaporator, heat exchanger, and the like.

The DC-DC converter 4 boosts the voltage of the fuel cell stack 3 with respect to the voltage of the drive motor 1 and the battery 2 so that the power generated by the fuel cell stack 3 can be extracted to the drive motor 1 and the battery 2. is a controller. The DC-DC converter 4 is connected in parallel to the fuel cell stack 3, boosts the output voltage of the fuel cell stack 3 on the primary side, and supplies generated power to the external load 100 on the secondary side. The DC-DC converter 4 increases the voltage of several tens of volts output from the fuel cell stack 3 to a voltage level of several hundreds of volts so that the power is supplied to the external load 100, for example.

A drive motor 1 is connected to a battery 2 and a DC-DC converter 4 via an inverter (not shown). The drive motor 1 is a power source that drives the vehicle. In addition, the drive motor 1 can generate regenerative electric power using the braking force required to brake the vehicle, and charge the battery 2 with this regenerative electric power.

The battery 2 is a power supply source that supplies stored power to the drive motor 1 . In this embodiment, the battery 2 is the main power source, and the fuel cell stack 3 is mainly used to charge the battery 2 when the charge of the battery 2 becomes low. Also, the electric power of the fuel cell stack 3 may be supplied to the drive motor 1 .

The controller 8 is composed of general-purpose electronic circuits and peripheral devices including a microcomputer, a microprocessor, and a CPU, and performs processing for controlling the fuel cell system 200 and the external load 100 by executing a specific program.

The controller 8 receives signals output from the current sensor 9, the accelerator opening sensor 10, and other various sensors, and acquires the remaining charge of the battery 2 according to these signals, or calculates the travelable distance described later. Calculate or obtain the required travel output. The controller 8 then controls the operation states of the drive motor 1, the fuel cell system 200, etc., based on these acquired or calculated values.

The controller 8 is connected to an operation unit (not shown) that outputs a start command signal or a stop command signal for the fuel cell system 200 . The operation unit includes an EV key, and outputs a start command signal to the controller 8 when the EV key is turned ON by the passenger, and outputs a stop command signal to the controller 8 when the EV key is turned OFF.

When the controller 8 receives a start-up command signal from the operation unit, the controller 8 performs start-up operation to start up the fuel cell system 200 . Conduct power generation operation to control power generation. Note that the fuel cell system 200 may be activated when the amount of charge in the battery 2 becomes equal to or less than a predetermined value that requires charging.

In power generation operation, the controller 8 determines the power required for the fuel cell stack 3 according to the operating state of the external load 100 . Then, the controller 8 calculates the supply flow rate of the cathode gas and the anode gas required for power generation of the fuel cell stack 3 based on the required electric power, and supplies the calculated supply flow rate of the anode gas and the cathode gas to the fuel cell stack 3 . supply to The controller 8 controls switching of the DC-DC converter 4 to supply the power output from the fuel cell system 200 to the external load 100 .

That is, the controller 8 controls the flow rate of the cathode gas and the anode gas based on the required power for the fuel cell stack 3 to control the power generation amount of the fuel cell stack 3 . For example, the required electric power for the fuel cell stack 3 increases as the amount of depression of the accelerator pedal increases. Therefore, as the amount of depression of the accelerator pedal increases, the flow rate of the cathode gas and the anode gas supplied to the fuel cell stack 3 increases. The cathode gas supplied to the fuel cell stack 3 may be controlled based on the deviation between the target temperature of the fuel cell stack 3 and the actual temperature. When the actual temperature is higher than the target temperature and the deviation is large, the supply amount of the cathode gas is increased compared to when the deviation is small.

In a system state in which the EV key is in the ON state and the power supply from the fuel cell system 200 to the external load 100 is stopped, the controller 8 suppresses the power generation of the fuel cell stack 3 and keeps the fuel cell suitable for power generation. Implement self-sustaining operation to maintain the state. Hereinafter, the system state in which the power supply from the fuel cell system 200 to the external load 100 is stopped will be referred to as the "idle stop (IS) state", and the independent operation will be referred to as the "IS operation".

When the required electric power for the fuel cell stack 3 reaches a predetermined value, for example zero, the operating state of the fuel cell system 200 transitions from the power generation operation to the IS operation. Controller 8 then controls DC-DC converter 4 to stop power supply from fuel cell system 200 to external load 100 .

Therefore, during the IS operation, the power generated by the fuel cell stack 3 may be supplied to the auxiliary equipment provided in the fuel cell system 200, or the power may not be supplied from the fuel cell stack 3 to the auxiliary equipment. good too.

When receiving a stop command signal from the operation unit, the controller 8 performs stop operation to stop the operation of the fuel cell system 200 .

2A to 2D are diagrams for explaining types of power supply to external load 100 in fuel cell system 200 with the EV key in the ON state.

FIG. 2A is a conceptual diagram showing a state in which the drive motor 1 is stopped and power is being supplied from the fuel cell system 200 to the battery 2. FIG. The state shown in FIG. 2A can occur when the vehicle is stopped and the amount of charge in the battery 2 is low.

FIG. 2B is a conceptual diagram showing a state in which drive motor 1 is in a power running state and power is being supplied to drive motor 1 from both fuel cell system 200 and battery 2 . The state shown in FIG. 2B can occur when the vehicle is accelerating and the load (output) of the drive motor 1 is high.

FIG. 2C is a conceptual diagram showing a state in which the drive motor 1 is in the power running state or the regeneration state and the power supply from the fuel cell system 200 to both the drive motor 1 and the battery 2 is stopped. The state shown in FIG. 2C can occur when the drive motor 1 is driven with a low or medium load while the vehicle is running and the battery 2 is fully charged. It can also occur when the vehicle is decelerating and the battery 2 has enough capacity to charge.

FIG. 2D is a conceptual diagram showing a state in which the drive motor 1 is stopped and the battery 2 is fully charged. The state shown in FIG. 2D can occur when the vehicle is stopped and the battery 2 is fully charged.

In this way, among the states shown in FIGS. 2A to 2D, the state shown in FIGS. 2C and 2D, that is, the system in which the power supply from the fuel cell system 200 to both the drive motor 1 and the battery 2 is stopped The state corresponds to the IS state of fuel cell system 200 . When the external load 100 enters the IS state, it transmits an IS operation request to the fuel cell system 200 .

Therefore, when the battery 2 is fully charged by the regenerative operation of the drive motor 1 while the vehicle is running, or when the battery 2 is fully charged and the vehicle is running or stopped, the fuel cell system 200 will not be IS. can become a state. In such a case, the required electric power to the fuel cell stack 3 becomes zero and the IS operation is performed.

Next, a method for calculating the distance that can be traveled from the current time, that is, the total distance that can be traveled will be described.

FIG. 3 is a diagram for explaining the relationship between the vehicle required output and the total travelable distance, which will be described later. In the figure, "Battery SOC" is the distance that the vehicle can travel on the power of the battery 2, and "Fuel" is the distance that the vehicle can travel on the power generated by the fuel cell stack 3.

In the hybrid vehicle according to this embodiment, the electric power that can be used for vehicle running is the electric power of the battery 2 and the electric power generated by the fuel cell stack 3 . As the required vehicle output increases, the power consumption increases, so the battery SOC portion and the fuel portion decrease. Therefore, by adding the battery SOC amount and the fuel amount, it seems that the total travelable distance can be calculated with high accuracy.

However, as will be explained below, the value calculated by the above calculation method may not be appropriate as an estimated value of the total travelable distance.

The SOFC used as the fuel cell stack 3 has the characteristic of generating a large amount of heat during operation. Considering the suppression of thermal expansion of the stacked cells due to the power generation of the fuel cell stack 3, it is not desirable to increase the number of stacked cells too much. Therefore, the fuel cell stack 3 used in this embodiment has a low power output of about 10 to 20 kW.

On the other hand, the output required for a vehicle to run (also called "vehicle required output") is the sum of the power required for driving the vehicle and the power consumed by the vehicle's accessories. In low-load running, such as when running a However, in high-load driving such as driving on a highway, the vehicle required output becomes larger than the power generation output of the fuel cell stack 3 . The term "vehicle auxiliary equipment" as used herein refers to electric equipment such as an air conditioner and lamps.

Therefore, if the electric power of the battery 2 is used up while the vehicle is running under a high load, the fuel cell stack 3 alone cannot generate the required vehicle output, so the high load running cannot be continued. That is, in a region in which the vehicle required output is larger than the SOFC maximum output in FIG. 3, the travelable distance for the amount of fuel indicated by the dashed line is the travelable distance at an output smaller than the vehicle required output. Therefore, the value obtained by simply adding the battery SOC amount and the fuel amount is not appropriate as an estimate of the total possible traveling distance because it deviates from the actual distance that the vehicle can travel at the requested output. No.

In the above description, high-load running was exemplified as an operating state in which the total travelable distance obtained by adding the travelable distance for the battery level SOC and the travelable distance for the fuel is not appropriate, but the present invention is not limited to this. . For example, when the fuel cell stack 3 is in a cold state, the power generation output is limited, and the fuel cell stack 3 alone may not be able to satisfy the vehicle's required output even when the vehicle is not running under a high load.

Further, in the above calculation method, both the battery SOC and the remaining amount of fuel used for calculation are values at the timing of calculating the total possible travel distance. However, if there is a section of travel in which the vehicle required output is smaller than the SOFC maximum output (hereinafter also referred to as a low-load section) after the timing of calculating the total possible mileage, power is generated while traveling in that section of battery SOC. can be increased. That is, since the above calculation method does not take into consideration the increase in battery SOC in low-load travel sections, the estimated total travelable distance may be shorter than the actual travelable distance.

Therefore, in the present embodiment, the following control is executed in order to accurately calculate the total travelable distance.

FIG. 4 is a flow chart showing a control routine for calculating the total travel distance in this embodiment. This control routine is programmed in the controller 8 as a total travelable distance calculator, and is repeatedly executed at intervals of, for example, several milliseconds. Note that this control routine is executed when the startup operation of the fuel cell stack 3 has been completed.

At step S100, the controller 8 acquires the battery SOC and the remaining amount of fuel. The battery SOC may be obtained, for example, by detecting and accumulating current values input to and output from the battery 2 by the current sensor 9, or may be obtained by other existing methods. The remaining amount of fuel may be obtained, for example, based on the detected value of a fuel gauge provided in the fuel tank 7, or may be obtained by other existing methods.

At step S110, the controller 8 acquires the current position of the vehicle, map information, and a future travel route. These information are obtained from a navigation system (not shown). A case where there is map information but no travel route is set, and a case where no travel route is set and there is no map information will be described later.

In step S120, the controller 8 calculates a travelable distance (first travelable distance) based on the current fuel state (battery SOC and remaining fuel amount). A specific calculation method will be described with reference to FIG.

FIG. 5 is a flow chart showing a control routine for calculating the first travelable distance, which is the processing executed in step S120 of FIG. Note that this control routine is executed when the startup operation of the fuel cell stack 3 has been completed.

In this embodiment, as will be described below, the total possible traveling distance is calculated using different methods depending on whether the required vehicle output is greater than or less than the power output of the fuel cell stack 3 .

At step S10, the controller 8 acquires the vehicle required output. Any of the following methods may be used to obtain the requested vehicle output.

The first method is to use an average value calculated based on accumulated past travel data. For example, the transition of the vehicle output demand when the current driving route has been traveled in the past is accumulated as driving data, and the average value of these is used as the vehicle demand output.

A second method is to use a preset value. For example, a typical vehicle required output for each condition such as a road surface gradient, speed limit, etc. is set in advance, and the vehicle required output to be used is determined based on the current travel route conditions.

It should be noted that the driver may select which of the first and second methods is to be used.

In step S<b>20 , the controller 8 calculates the battery outputtable power amount, which is the power amount that can be output with the remaining charge of the battery 2 . The calculation method may be a method of calculating using a formula using the SOC of the battery 2 as a parameter, or a method of mapping the relationship between the SOC of the battery 2 and the amount of power that can be output in advance and searching the map.

At step S30, the controller 8 acquires the average vehicle speed. The average vehicle speed referred to here is the average value of the vehicle speed when the vehicle runs at the vehicle required output obtained in step S10. A calculation using a mathematical formula with the vehicle output power as a parameter may be performed, or the relationship between the vehicle output power and the average vehicle speed may be mapped in advance and searched.

In step S<b>40 , the controller 8 determines whether or not the vehicle required output is greater than the power generation output of the fuel cell stack 3 . The power generation output used here is basically the maximum power generation output of the fuel cell stack 3, but if the power generation output of the fuel cell stack 3 is limited for reasons such as being in a cold state, the power generation output is limited. use the value.

The controller 8 executes a travelable distance calculation A in step S50 when the determination result is yes, and executes a travelable distance calculation B in step S60 when the determination result is no.

The travelable distance calculation A will be described.

As described above, when the requested vehicle output is greater than the power output of the fuel cell stack 3, when the remaining charge of the battery 2 is exhausted, that is, when the battery 2 is used up, even if fuel remains, It becomes impossible to run at the vehicle's requested output. In other words, the vehicle can run at the required output while the excess of the required vehicle output over the power output of the fuel cell stack 3 can be covered by the output power of the battery 2 . In other words, the travelable distance is the travelable distance until the amount of power that can be output from the battery 2 is used up by the excess of the vehicle required output to the power output of the fuel cell stack 3 . If this is represented by an equation, it becomes equation (1). Note that Formula 1 for calculating the travelable distance calculation A is based on the premise that fuel is continuously supplied to the fuel cell stack 3 during the period in which the vehicle travels the distance. Processing when the fuel cell is insufficient for traveling the distance will be described later in the second embodiment.

L_A = Wbat [kWh] ÷ (F [kW] - P [kW]) x Vave [km/h] (1)

L_A: Drivable distance, Wbat: Battery output power capacity, F: Vehicle demand output, P: Fuel cell power output, Vave: Average vehicle speed

It should be noted that Wbat in the formula (1) in this step is based on the current fuel state. For example, when the vehicle required output is 20 [kW], the fuel cell power generation output is 15 [kW], the current battery output power amount is 10 [kWh], and the vehicle required output is 20 [kW], the average vehicle speed is 100 [kW]. km/h], Equation (1) becomes as follows.

L_A = 10 [kWh] ÷ (20 [kW] - 15 [kW]) x 100 [km/h]

= 2 [h] x 100 [km/h]
= 200 [km]

The power output of the fuel cell is determined by the specifications of the fuel cell stack 3, and the average vehicle speed is also determined when the required output of the vehicle is determined. Therefore, various values are substituted in advance for the battery output power capacity and the vehicle demand output, and the equation (1) is calculated. It is also possible to obtain the travelable distance by searching a map using the available electric energy and the vehicle's required output. Obtaining the travelable distance by map search is also included in "calculating". In the following description, the travelable distance calculated by the travelable distance calculation A is also referred to as "travelable distance A".

Next, the travelable distance calculation B will be described.

The travelable distance calculation B is the calculation method described in the above-mentioned literature. In other words, electric power (hereinafter referred to as " This is a method of adding the distance calculated based on the remaining fuel electric energy). If this is made into a formula, it will become Formula (2).

L_B＝(Wbat[kWh]+Wfuel[kWh])÷F[kW]×Vave[km/h] (2)

L_B: Travelable distance, Wbat: Battery output power, Wfuel: Remaining fuel power,

F: vehicle demand output, Vave: average vehicle speed

If the required output of the vehicle is equal to or less than the power output of the fuel cell stack 3, the vehicle can run according to the required output even after the battery 2 runs out of power. It is possible to calculate the distance that can be traveled. Therefore, as the travelable distance calculation B, the calculation method of the literature described above is used.

The travelable distance calculation B may also be calculated by searching a map in the same manner as the travelable distance A. In this case, the parameters used for the map search are the available battery output power amount, the vehicle required output, and the remaining fuel power amount. In the following description, the travelable distance calculated by the travelable distance calculation B is also referred to as "travelable distance B".

When the travelable distance A or the travelable distance B is calculated in this manner, the controller 8 stores the calculation result, returns to the flow chart of FIG. 4, and executes the subsequent step S130. In the following description, the travelable distance A or the total travelable distance B calculated in step S120 of the flow of FIG. 4 is referred to as "first travelable distance".

In step S130, the controller 8 predicts the chargeable section. A chargeable section is a travel section in which the required vehicle output is smaller than the output obtained from the power generated by the fuel cell stack 3 . In this process, based on the information acquired in step S110, it is determined whether or not there is a chargeable section on the next travel route.

In step S140, the controller 8 determines a second travelable distance, which is the distance that can be traveled, based on the amount of electric power generated by the fuel cell stack 3 generating power (hereinafter also referred to as the charge increase amount) while traveling in the chargeable section. calculate. Here, a method for calculating the second travelable distance will be described.

The charge increase amount is the amount of electric power charged while traveling in the chargeable section as described above. In other words, the vehicle is charged with the surplus power generated by the fuel cell stack 3 with respect to the power required to satisfy the vehicle output demand when traveling in the chargeable section (hereinafter also referred to as fuel cell surplus power). Electricity. The fuel cell surplus power is the power generated by the fuel cell stack 3 minus the power required to satisfy the vehicle output demand in the chargeable section. If the result of the subtraction is a negative value, the fuel cell surplus power is set to zero. Also, the power output of the fuel cell stack 3 used in the calculation is the maximum power output of the fuel cell stack 3 .

The charging increase amount is obtained by multiplying the fuel cell surplus electric power calculated as described above by the time required for traveling in the chargeable section (hereinafter also referred to as surplus electric power charging time). The surplus power charging time may be calculated, for example, based on the distance of the chargeable section and the speed limit of the section. Further, instead of the speed limit for the section, the average vehicle speed for the section calculated from past travel data may be used. Since the fuel cell surplus power continues to change while the vehicle is traveling in the chargeable section, the fuel cell surplus power is actually integrated from the start to the end of the surplus power charging time.

After calculating the charge increase amount, the controller 8 calculates the possible travel distance by replacing the battery output power amount Wbat in the formula (1) or formula (2) used in step S120 with the charge increase amount. When the first travelable distance is the travelable distance A, the formula (1) is used, and when the first travelable distance is the travelable distance B, the formula (2) is used.

In step S150, the controller 8 sums the first travelable distance calculated in step S120 and the second travelable distance calculated in step S140 to obtain an estimated total travelable distance.

At step S160, the controller 8 displays the total possible travel distance calculated at step S150 to the driver. The display location may be any location that can be visually recognized by the driver.

It should be noted that if the requested vehicle output is greater than the fuel cell power output in step S40 of FIG. At step S150, the total travelable distance may be calculated by the following equation (1)'.

L_total = (Wbat [kWh] + Wcharge) ÷ (F [kW] - P [kW]) x Vave [km/h] (1)´

L_total: total mileage, Wbat: battery output power, Wcgarge: charge increase, F: vehicle demand output, P: fuel cell power output, Vave: average vehicle speed

That is, the total travelable distance is based on the shortfall of the power generation output of the fuel cell stack 3 (generator) with respect to the vehicle required output and the total battery charge amount obtained by adding the charge increase amount to the current remaining charge amount of the battery 2. may be calculated.

Note that if it is predicted in step S130 that there is no chargeable section, the second travelable distance calculated in the process of step S140 becomes zero [km]. Therefore, the process of step S140 may be executed only when it is predicted that there is a chargeable section in step S130.

Next, the effect of calculating the total travelable distance as described above will be described with reference to FIGS. 6 to 9. FIG.

FIG. 6 is a timing chart showing an example of running patterns. The vertical axis in FIG. 6 is the output [kW]. The solid line in the figure indicates the vehicle required output. The dashed line in the figure indicates the maximum output of the fuel cell stack 3, that is, the output of the drive motor 1 obtained when the fuel cell stack 3 generates the maximum electric power.

The running pattern shown in FIG. 6 runs in the chargeable section from timing 0 to timing T1, and runs in the high-load running region after timing T1. When traveling in this driving pattern, the surplus power charging time is from timing 0 to timing T1 in the present embodiment, and the total possible traveling distance is calculated in consideration of the amount of charging increase during this period (area of hatched area A). do.

When the charge increase amount is not considered, the difference between the vehicle required output and the maximum output of the fuel cell stack 3 during high-load running is calculated based on the battery SOC at timing 0 (the shaded area B). area), that is, from timing T1 to timing T2 is the possible running time in the high-load state, and the total possible running distance is obtained by multiplying the possible running time by the vehicle speed. In other words, although it is actually possible to run with the electric power (charge increase amount) that was charged before starting high-load running, only the possible running distance is calculated based on the battery output power amount determined based on the battery SOC at timing 0. .

In contrast, in the present embodiment, the difference between the vehicle required output and the maximum output of the fuel cell stack 3 during high-load running is determined based on the battery SOC at timing 0 (the area of the hatched area B). and the amount of charge increase (hatched area C=hatched area A) is the time that can be traveled in the high load state. Then, the total travelable distance is obtained by multiplying the travelable time by the vehicle speed.

As described above, it is possible to calculate the total travelable distance with high accuracy by taking into consideration the charge increase amount when calculating the total travelable distance.

FIGS. 7 to 9 summarize data for trial calculations using specific numerical values and trial calculation results in tables.

FIG. 7 is a table summarizing the relationship between the vehicle speed and the required vehicle output at the vehicle speed of the vehicle used for trial calculation.

FIG. 8 shows the capacity of the battery 2 installed in the vehicle used for the trial calculation, the maximum generated power of the fuel cell stack 3, the SOC at the time when the estimated travelable distance is calculated, and the vehicle traveling at 100 [km/h] in this SOC state. FIG. 10 is a table of a travelable distance (a first travelable distance) in a case where the vehicle is driven;

FIG. 9 is a table summarizing trial calculation results of the travelable distance (the second travelable distance described above) in the charging increase amount in the chargeable section.

8 and 9 are calculated on the assumption that the power output of the fuel cell stack 3 is the maximum.

When the capacity of the battery 2 is 20 [kWh] and the maximum output of the fuel cell stack 3 is 20 [kW], as is clear from FIG. . In addition, when the battery SOC is 25[%], the battery output power is 5 [kWh], and the travelable distance when high load running (running at 100 [km/h]) is performed only with this power. is calculated as 50 [km] by the above formula (1). When the battery SOC is 50[%], the battery output power is 10[kW], and the calculation result of the possible travel distance in high-load travel is 100 [km].

In other words, if the battery SOC is 25[%], the total possible traveling distance is 50[km], and if the battery SOC is 50[%], the total possible traveling distance is obtained without considering the charge increase amount in the chargeable section. is 100 [km].

However, in the present embodiment, when calculating the total travelable distance, the travelable distance with the amount of increase in charging is also taken into consideration. Therefore, the vehicle speed in the chargeable section has three patterns of 20 [km/h], 40 [km/h], and 60 [km/h], and the traveling time in the chargeable section is 15 [min] and 30 [km/h]. min], the charge increment and the travelable distance at that charge increment were calculated, and the results are summarized in FIG.

A method of calculating the charge increase amount and the second travelable distance will be described using an example of travel conditions where the travel time is 15 [min] and the vehicle speed is 20 [km/h].

The output required for traveling at a vehicle speed of 20 [km/h] is 2 [kW] as shown in FIG. Therefore, if the output of the fuel cell stack 3 is the maximum power generation output, the fuel cell surplus power will be 18 [kW]. Assuming that the running time with this fuel cell surplus power is 15 [min], the charge increase amount is 18 [kW]×15 [min]÷60, which is 4.5 [kWh].

Then, the second travelable distance is obtained by replacing the possible output power amount Wbat of the battery in the above equation (1) with the charge increase amount, and is the output required for traveling at the vehicle required output F of 100 [km/h]. [kW], the fuel cell power generation output P is 20 [kW], which is the maximum power generation output, and the average vehicle speed Vave is 100 [km/h]. As a result, the second travelable distance becomes 45 [km]. Other driving conditions can also be calculated in a similar manner.

As shown in FIG. 9, when the running time of the chargeable section is 15 [min], it is possible to run 20 to 45 [km], and when it is 30 [min], it is possible to run 40 to 90 [km]. becomes possible.

As described above, in the present embodiment, the controller 8 determines whether or not there is a chargeable section, which is a section in which the fuel cell stack 3 (generator) can be charged during running, and the battery 2 is charged based on the result of the determination. The amount of charge is calculated, and the total travelable distance is calculated based on parameters including the amount of charge in the battery 2 and the remaining amount of fuel in the fuel cell stack 3 . In this way, since the amount of charge of the battery 2, which is one of the parameters used to calculate the total travel distance, is calculated based on the determination result of whether or not there is a chargeable section, only the remaining amount of charge of the battery 2 at the present time is used as a parameter. The accuracy of the calculation result is higher than when calculating the total travel distance as .

In this embodiment, the controller 8 calculates the charge increase amount, which is the amount of electric power charged by the power generated by the fuel cell stack 3 while traveling in the chargeable section, and adds the charge increase amount to the current remaining charge amount of the battery 2. to calculate the total battery charge. Then, the controller 8 calculates the total possible traveling distance based on the shortfall of the power generation output of the fuel cell stack 3 with respect to the vehicle required output and the total battery charge amount. As a result, even when the power output of the fuel cell stack 3 is relatively small, the controller 8 can accurately calculate the total travelable distance in high-load running where the required vehicle output exceeds the power output of the fuel cell stack 3. .

According to this embodiment, the controller 8 calculates the charge increase amount by integrating the value obtained by subtracting the vehicle required output in the chargeable section from the power generation output of the fuel cell stack 3 . As a result, the controller 8 can appropriately calculate the charge increase amount in accordance with changes in the vehicle required output and the generated power.

In this embodiment, the charging increase amount is calculated only when the vehicle required output is smaller than the power generation output of the fuel cell stack 3 . Thereby, the calculation load of the controller 8 can be reduced.

In this embodiment, the controller 8 acquires road map information, vehicle position information, and travel route information to the destination. A low-load running section that does not exceed the electric power is predicted as a chargeable section. Then, the controller 8 calculates the requested vehicle output in the chargeable section, and calculates the charge increase amount in the chargeable section based on the calculated requested vehicle output and the power generated by the fuel cell stack 3 . If the road map information and the travel route information can be acquired, it is possible to accurately calculate the required vehicle output and the travel distance on the future travel route. Therefore, the charge increase amount can also be calculated with high accuracy.

In the present embodiment, the controller 8 sets the power output of the fuel cell stack 3 used for the above calculation as the maximum power output of the fuel cell stack 3 . As a result, the charge increase amount in the chargeable section can be increased.

In this embodiment, the controller 8 calculates the vehicle required output based on the power required for running the vehicle and the power consumption of the vehicle accessories. As a result, the total travelable distance can be calculated more accurately.

(Second embodiment)
A second embodiment will be described. A hybrid vehicle to which this embodiment is applied is the same as that of the first embodiment. Also, the method of calculating the total travelable distance in this embodiment is basically the same as in the first embodiment. However, this embodiment differs from the first embodiment in that no travel route is set. This difference will be mainly described below.

If the travel route is not set, the controller 8 cannot acquire the travel route in step S110 of FIG. If the travel route is not determined, the controller 8 cannot predict the chargeable section in step S130 of FIG. 4 as in the first embodiment.

Therefore, in step S130 of FIG. 4, the controller 8 predicts the chargeable section by the following method.

In this embodiment, although the travel route is not set, the position information and map information of the own vehicle can be acquired. Therefore, based on these obtainable information, the controller 8 searches for the start point of high-load driving such as the entrance of the highway and the starting point of the uphill in the vicinity of the own vehicle, and starts the high-load driving closest to the current position. Identify location. Then, the section from the current position to the starting point of high-load running is predicted as a chargeable section.

Once the chargeable section is predicted, the calculation of the second travelable distance (S140 in FIG. 4) can be performed in the same manner as in the first embodiment.

As described above, in this embodiment, the controller 8 acquires the road map information and the position information of the own vehicle, and from the current position, the point at which the requested vehicle output exceeds the power generated by the fuel cell stack 3 and starts high-load driving. up to is predicted as a chargeable section. Then, the controller 8 calculates the required vehicle output in the chargeable section, and calculates the battery charging amount generated by the generator in the chargeable section based on the calculated requested vehicle output and the power generated by the generator. As a result, even if the travel route is not set, it is possible to estimate how long the chargeable section will continue and with what kind of load, and to accurately calculate the charge increase amount.

(Third embodiment)
A third embodiment will be described. A hybrid vehicle to which this embodiment is applied is the same as that of the first embodiment. Also, the method of calculating the total travelable distance in this embodiment is basically the same as in the first embodiment. However, this embodiment differs from the first embodiment in that there is no map information. If there is no map information, naturally the travel route is not set. That is, in this embodiment, there is no information acquired in step S110 of FIG. This difference will be mainly described below.

Without the map information, the controller 8 cannot acquire the map information and the travel route in step S110 of FIG. 4, so the controller 8 cannot predict the chargeable section in step S130 of FIG. 4 as in the first embodiment. . If the chargeable section cannot be predicted, the charge increase amount cannot be calculated.

Therefore, in the present embodiment, the controller 8 calculates the charging increase amount by the following method without performing the process of step S130 in FIG.

FIG. 10 is a flow chart showing a control routine for calculating the charge increase amount in this embodiment. This control routine is programmed in the controller 8 .

In step S200, the controller 8 calculates the average value of the vehicle required output based on the past running state data. Various types of data can be used as data on past driving conditions, such as data for one trip from departure to arrival at a destination, data for a predetermined driving time, etc. However, an average value calculated based on long-term data is , there is a risk that the current driving state cannot be represented appropriately. Therefore, in this embodiment, the level of the vehicle output power is divided into a plurality of ranges, and the average of the vehicle power output is calculated based on the data after the running state of the vehicle enters the range of the current vehicle power output level. Calculate the value. For example, the vehicle required output is divided into a low load level (0 kW or more and less than 10 kW), a medium load level (10 kW or more and less than 20 kW), and a high load level (20 kW or more). The average value of the vehicle required output is calculated based on the data from the time the load level was entered until the present time. As a result, it is possible to calculate an average value that appropriately reflects the current running state.

At step S210, the controller 8 calculates the fuel cell surplus power. Specifically, the average value of the vehicle required output calculated in step S200 is subtracted from the fuel cell maximum power output. If the average value of the vehicle required output is greater than the fuel cell maximum generated output, the surplus generated power of the fuel cell is set to zero.

In step S<b>220 , the controller 8 calculates the power generation continuable time based on the fuel consumption corresponding to the generated power and the remaining amount of fuel in the fuel tank 7 . The power generation continuation possible time is the time during which power generation can be continued with the current remaining amount of fuel, in other words, the time until the fuel runs out. Specifically, the controller 8 divides the remaining amount of fuel in the fuel tank 7 by the amount of fuel consumed according to the generated power.

At step S230, the controller 8 calculates the charge increase amount. Specifically, the fuel cell surplus power output calculated in step S210 is multiplied by the power generation continuation time calculated in step S220.

Note that an upper limit is set for the amount of charge of the battery 2 in order to prevent deterioration of the battery 2 or the like. Therefore, the charge increase amount is limited to a range until the charge amount of the battery 2 reaches the upper limit.

After calculating the charge increase amount by the above method, the controller 8 executes the processing of steps S140 to S160 in FIG. As a result, even if the travel route is not set and there is no map information, it is possible to calculate the second travelable distance based on the charge increase amount before high-load travel.

As described above, in the present embodiment, when there is no road map information and travel route information to the destination, the controller 8 uses the average value of the most recent vehicle required outputs as the vehicle required output in the chargeable section. As a result, even if there is no road map information and no travel route is set, it is possible to calculate the required vehicle output in the chargeable section.

In the present embodiment, the controller 8 defines a section from the current position until the battery 2 is fully charged or until the fuel in the fuel cell stack 3 runs out as a chargeable section. As a result, even if there is no road map information and no travel route is set, it is possible to estimate how far the chargeable section will continue.

Next, a modification of the method for calculating the first travelable distance in step S120 of FIG. 4 will be described. Any of the following modifications are included in the scope of the present invention.

(First modification)
FIG. 11 is a flow chart showing a control routine for calculating the first travelable distance. This control routine is programmed in the controller 8 and is repeatedly executed, for example, at intervals of several milliseconds. The control routine of FIG. 11 determines whether the remaining amount of fuel in the fuel tank is insufficient for traveling the possible traveling distance A after the controller 8 has calculated the possible traveling distance A (step S50). is different from the control routine in FIG. 5 in that determination (step S55) is executed.

The control routine in FIG. 5 is based on the premise that the fuel is continuously supplied to the fuel cell stack 3 during the period of running the distance. For example, when the vehicle required output is 30 [kW], the fuel cell power generation output is 20 [kW], the current battery output power capacity is 10 [kWh], and the vehicle required output is 30 [kW], the average vehicle speed is 100 [kW]. km/h]. In this case, since it is possible to travel for one hour at an average vehicle speed of 100 [km/h], the total travelable distance A is 100 [km]. That is, the travelable distance A of 100 [km] is a value based on the premise that the fuel will last for one hour.

However, for example, if the fuel consumption rate is 10 [L/h] and the remaining amount of fuel is 5 [L] when generating the power output of the fuel cell stack 3 in Equation (1), the fuel will be consumed in 30 minutes. Since it disappears, it cannot run 100 [km].

Therefore, in step S55, the controller 8 determines whether or not the remaining amount of fuel in the fuel tank is insufficient for traveling the allowable distance A. Specifically, first, the controller 8 calculates the time until the remaining amount of fuel runs out from the fuel consumption rate of the fuel cell stack 3 and the remaining amount of fuel. Note that the controller 8 stores in advance the fuel consumption rate for each power generation output of the fuel cell stack 3 . Also, the remaining amount of fuel is detected by a known technique. For example, the fuel tank 7 is provided with a fuel sensor for detection.

Then, the controller 8 compares the time until the fuel runs out with the travelable time calculated in the process of the travelable distance calculation A, and if the time until the fuel runs out is shorter, it determines that the fuel is insufficient. do.

When the required vehicle output is greater than the power generation output of the fuel cell stack 3, the travelable distance calculation A can calculate a value closer to the actual travelable distance than the travelable distance calculation B can. However, when the fuel is insufficient, the premise of the possible travel distance calculation A collapses, so the accuracy of the allowable travel distance A becomes worse than that of the allowable travel distance B.

Therefore, if the determination result of step S55 is YES, the controller 8 executes a travelable distance calculation B in step S60.

If the determination result is no, it means that the travelable distance A can be traveled, so the controller 8 sets the travelable distance A calculated in step S50 as the first travelable distance.

As described above, in this modification, when the vehicle required output is smaller than the maximum power output of the fuel cell stack 3, and the time until the battery 2 runs out of electric power that can be used for running, the fuel cell stack 3 is used for power generation. If it is longer than the time until the fuel runs out, the travelable distance determined from the remaining charge of the battery 2 and the amount of electric power obtained by generating power using all of the remaining fuel. The determined travelable distance and the determined travelable distance are added to calculate the travelable distance. Also, when the requested vehicle output is greater than the maximum power output of the fuel cell, the time until the battery 2 runs out of power that can be used for running is less than or equal to the time until the fuel used for power generation in the fuel cell stack 3 runs out. In some cases, the possible travel distance determined from the shortfall of the power output of the generator with respect to the travel output and the remaining charge of the battery is calculated. According to this, when the fuel is exhausted earlier than the power of the battery 2 and the vehicle cannot actually travel the travelable distance A, the travelable distance B with higher accuracy than the travelable distance A can be calculated.

(Second modification)
In the first embodiment, the second embodiment, and the first modification, the control routine for calculating the total travelable distance in the state where the start-up operation of the fuel cell stack 3 is completed has been described. A control routine that can accurately calculate the total travelable distance even when the stack 3 is not in operation will be described.

The system configuration of the hybrid vehicle to which this modified example is applied is the same as the configuration of the first embodiment. This hybrid vehicle runs on the power of the battery 2 only when the fuel cell stack 3 is not in operation. Further, the fuel cell stack 3 used in this modified example is an SOFC, and the SOFC requires several tens of minutes or more from the start of start-up operation to the end of start-up operation.

Therefore, when calculating the total travelable distance in a state where the startup operation of the fuel cell stack 3 has not been completed, it is necessary to take into consideration that the SOC and remaining amount of fuel of the battery 2 change from the start of the startup operation to the end of the startup operation. There is a need to. Therefore, in the present embodiment, the total travelable distance is calculated in consideration of the above change.

FIG. 12 is a flow chart showing a control routine for calculating the total travel distance in this modified example. As will be explained below, when the fuel cell stack 3 is not in operation, the controller 8 calculates the total possible travel distance by adding the travel distance until the end of the start-up operation and the travelable distance after the end of the start-up operation. do. This control routine is programmed in the controller 8 and is repeatedly executed, for example, at intervals of several milliseconds. Steps S10, S30, S40-S70 are the same as the control routine of FIG.

In FIG. 12, step S30 is executed after the process of step S10, and then the processes of steps S32 to S38 described below are executed. Then, after the process of step S38, the process of step S39, which is the same process as that of step S20 in FIG. 11, is executed.

At step S32, the controller 8 determines whether or not the fuel cell stack 3 is in operation, and if it is in operation, executes the processing from step S39 onwards.

When the controller 8 determines in step S32 that the fuel cell stack 3 is not in operation, in step S34, the controller 8 calculates the distance traveled until the end of the start-up operation. Specifically, the controller 8 stores in advance the time required from the start of the fuel cell stack 3 to the end of the start-up operation, and calculates the traveling distance until the end of the start-up operation from this time and the average vehicle speed.

In step S36, the controller 8 calculates the SOC of the battery 2 at the end of the startup operation. Specifically, the controller 8 calculates the amount of power consumed by traveling the distance calculated in step S2, and from this amount of power and the current SOC of the battery 2, the SOC of the battery 2 at the end of the starting operation is calculated. Calculate

At step S38, the controller 8 calculates the remaining amount of fuel at the end of the startup operation. Specifically, the controller 8 calculates the amount of fuel to be consumed from the start of the start-up operation to the end of the start-up operation, and from this fuel amount and the current remaining amount of fuel, calculates the remaining amount of fuel at the end of the start-up operation.

After completing the process of step S38, the controller 8 executes the processes of step S39 and subsequent steps. At this time, in step S39, the controller 8 calculates the battery outputtable power amount, which is the power amount that can be output at the battery SOC estimated in step S36. In step S50, the controller 8 sets the travelable distance A by adding the traveled distance until the end of the starting operation to the value calculated by the first travelable distance calculation described above. In step S60, the controller 8 uses the remaining fuel power amount Wfuel in equation (2) as the power amount with the remaining amount of fuel at the end of the start-up operation to calculate the possible travel distance, and the travel distance until the end of the start-up operation is added to this calculated value. The added value is defined as the travelable distance B.

In addition, in the present modification, the time from the start to the end of the start-up operation is also excluded from the surplus power charging time when calculating the charge increase amount.

As described above, in this modification, when the fuel cell stack 3 is not in operation, the controller 8 determines the travel distance until the start-up operation of the fuel cell stack 3 ends and the start-up operation based on the vehicle required output. The remaining charge amount and the remaining amount of fuel of the battery 2 at the time of termination are estimated. Then, the controller 8 performs a travelable distance calculation A or a travelable distance calculation B based on the estimated value of the remaining charge of the battery 2 and the estimated value of the remaining amount of fuel at the time when the start-up operation is completed, thereby completing the start-up operation. Calculate the subsequent travelable distance. The controller 8 determines the first possible travel distance by adding the travelable distance after the end of the start-up operation and the travel distance until the end of the start-up operation. As a result, when the fuel cell stack 3 is not in operation, it is possible to calculate an appropriate total travelable distance according to changes in the SOC of the battery 2 and changes in the remaining amount of fuel while waiting for the end of the start-up operation. .

In each of the above-described embodiments and modifications, the case where the generator is the fuel cell system 200 has been described, but the present invention is not limited to this. For example, instead of the fuel cell system 200, each embodiment and each modification can be applied when using a system including an internal combustion engine and a generator that is driven by the internal combustion engine to generate power. This is because if the power output of the generator generated by the internal combustion engine is lower than the vehicle required output, problems similar to those to be solved in each of the embodiments and modifications arise. In addition, the time required from the start to the end of start-up operation of the internal combustion engine is much shorter than that of the SOFC, and the change in the SOC of the battery 2 and the change in the remaining amount of fuel from the start to the end of start-up operation can be ignored. .

Moreover, it goes without saying that the present invention is not limited to the above-described embodiments, and that various modifications can be made within the scope of the technical idea described in the claims.

REFERENCE SIGNS LIST 1 drive motor 2 battery 3 fuel cell stack 8 controller 100 external load 200 fuel cell system

Claims (10)

In a mileage calculation method for a hybrid vehicle that supplies a load with power from a battery and power generated by a generator,
Determining whether there is a chargeable section, which is a section in which charging by the generator is possible while driving,
calculating a charging increase amount, which is the amount of electric power generated by the generator while traveling in the chargeable section , based on the result of the determination;
calculating a total battery charge by adding the charge increment to the current remaining charge of the battery;
A mileage calculation method for a hybrid vehicle, wherein a total possible mileage is calculated based on a shortage of the power generation output of the generator with respect to the vehicle demand output and the total battery charge amount . In the hybrid vehicle mileage calculation method according to claim 1 ,
A mileage calculation method for a hybrid vehicle, wherein the charge increase amount is calculated by integrating a value obtained by subtracting the vehicle required output in the chargeable section from the power generation output of the generator. In the hybrid vehicle mileage calculation method according to claim 2 ,
A mileage calculation method for a hybrid vehicle, wherein the charging increase amount is calculated only when the vehicle required output is smaller than the power generation output of the generator. In the hybrid vehicle mileage calculation method according to any one of claims 1 to 3 ,
Acquire road map information, vehicle position information, and driving route information to the destination,
predicting, as the chargeable section, a low-load travel section on the travel route to the destination where the vehicle output required does not exceed the power generated by the generator;
calculating the vehicle required output in the chargeable section;
A mileage calculation method for a hybrid vehicle, wherein a battery charge amount generated by the generator in the chargeable section is calculated based on the calculated vehicle required output and the power generated by the generator. In the hybrid vehicle mileage calculation method according to any one of claims 1 to 3 ,
Acquiring road map information and vehicle position information,
Predicting the chargeable section from the current position to the point where the vehicle required output exceeds the power generated by the generator and starts high-load running,
calculating the vehicle required output in the chargeable section;
A mileage calculation method for a hybrid vehicle, wherein a battery charge amount generated by the generator in the chargeable section is calculated based on the calculated vehicle required output and the power generated by the generator. In the hybrid vehicle mileage calculation method according to claim 2 or 3 ,
A mileage calculation method for a hybrid vehicle, wherein, when road map information and travel route information to a destination are not available, an average value of the vehicle's most recent requested output is used as the vehicle's requested output in the chargeable section. In the hybrid vehicle mileage calculation method according to claim 6 ,
A mileage calculation method for a hybrid vehicle, wherein a section from a current position until the battery is fully charged or until the generator runs out of fuel is defined as the chargeable section. In the hybrid vehicle mileage calculation method according to any one of claims 1 to 7 ,
A mileage calculation method for a hybrid vehicle, wherein the power output of the generator is the maximum power output of the generator. In the hybrid vehicle mileage calculation method according to any one of claims 1 to 8 ,
A mileage calculation method for a hybrid vehicle, wherein the vehicle required output is calculated based on the power required for running the vehicle and the power consumption of vehicle accessories. In a mileage calculation device for a hybrid vehicle that supplies power from a battery and power generated by a generator to a load,
Equipped with a total drivable distance calculation unit that calculates the total drivable distance,
The total travelable distance calculation unit,
determining whether or not there is a chargeable section, which is a section in which power can be generated by the generator while the vehicle is running;
calculating a charging increase amount, which is the amount of electric power generated by the generator while traveling in the chargeable section, based on the result of the determination;
calculating a total battery charge by adding the charge increment to the current remaining charge of the battery;
A mileage calculation device for a hybrid vehicle, which is programmed to calculate a total possible mileage based on a shortage of the power generation output of the generator with respect to the vehicle demand output and the total battery charge .

Images