Electric vehicle control method and electric vehicle control device

Abstract

Provided is an electric vehicle control method in which a battery is charged using an in-vehicle power generation system. In this control method, a travel route of the electric vehicle is acquired, an uphill section included in the travel route is determined, the travel energy required for traveling in the uphill section is calculated, and an upper limit vehicle speed is set on the basis of the travel energy and the fuel consumption characteristics of the power generation system. When the vehicle is traveling in the uphill section, the vehicle speed is limited to the upper limit vehicle speed or lower.

Description

Control method for electric vehicle and control device for electric vehicle

[0001] The present invention relates to a control method and a control device for an electric vehicle.

[0002] JP2006-193095A discloses a driving assistance system that provides driving assistance based on a desired driving speed preset by the driver for each road type. For example, this driving assistance system provides driving assistance by notifying the driver that the desired driving speed is being exceeded, or by automatically decelerating the vehicle to reach the desired speed.

[0003] An electric vehicle may include a power generation system that charges a battery. In this manner, in an electric vehicle including a power generation system, the power generation system is appropriately driven so that the SOC (State of Charge), which represents the charge amount of the battery, is maintained within a predetermined range. Specifically, the power generation system is driven when the SOC falls below a predetermined lower limit, and then stopped when the SOC reaches or exceeds a predetermined upper limit. At this time, the power generation system is usually driven in the best operating state (operating point) that provides good fuel economy and minimizes noise and vibration.

[0004] However, when the SOC falls below a predetermined reference value and driving energy is insufficient, or there is a risk of this occurring, it is necessary to ensure driving energy by increasing the amount of power generated by relaxing the restrictions on driving conditions that take fuel economy, noise, and vibration into consideration. For example, when driving on an uphill road where the SOC decreases significantly under high load, it may not be possible to maintain the SOC even with power generation under the best driving conditions that take fuel economy, noise, and vibration into consideration. For this reason, it becomes necessary to operate the power generation system under driving conditions that result in poor fuel economy or that are likely to generate noise and vibration.

[0005] The present invention aims to provide a control method and control device for an electric vehicle that can overcome a high-load uphill road by generating power under the best driving conditions, while avoiding power generation under driving conditions that result in poor fuel efficiency or that are prone to noise and vibration.

[0006] One aspect of the present invention is a control method for an electric vehicle that charges a battery using an on-board power generation system. This control method acquires a travel route for the electric vehicle, determines whether the travel route includes an uphill section, calculates the travel energy required for travel on the uphill section, and sets an upper limit vehicle speed based on the travel energy and the fuel consumption characteristics of the power generation system. Then, when traveling on the uphill section, the vehicle speed is limited to be equal to or less than the upper limit vehicle speed.

[0007] FIG. 1 is an explanatory diagram showing a schematic configuration of an electric vehicle. FIG. 2 is a block diagram showing the configuration of a controller. FIG. 3 is a graph showing the relationship between driving energy and generated energy in an uphill section. FIG. 4 is an explanatory diagram showing the balance between driving energy and generated energy in an uphill section. FIG. 5 is an explanatory diagram showing the SOC after traveling through an uphill section. FIG. 6 is a flowchart of vehicle speed limit control. FIG. 7 is a graph showing changes in SOC and other parameters when traveling through an uphill section. FIG. 8 is a block diagram showing the configuration of a controller according to a second embodiment. FIG. 9 is an explanatory diagram showing how fuel consumption is calculated according to vehicle speed. FIG. 10 is a graph showing fuel consumption and traveling time in an uphill section. FIG. 11 is a graph showing evaluation values ​​according to vehicle speed. FIG. 12 is a flowchart of vehicle speed limit control according to the second embodiment.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] [First embodiment] Fig. 1 is a block diagram showing a schematic configuration of an electric vehicle 100. As shown in Fig. 1, the electric vehicle 100 is a so-called series hybrid vehicle, and includes a battery 10, an electric motor 11, a power generation system 12, a navigation system 13, and a controller 14.

[0010] The battery 10 is a DC power source that supplies power to the electric motor 11. The battery 10 is composed of a lithium ion battery or the like and is rechargeable. The battery 10 is charged by the power generated by the power generation system 12. When the electric motor 11 is rotated by the driving wheels 15, the battery 10 is charged by the regenerative energy input from the electric motor 11. The charge amount of the battery 10 is expressed by SOC [%]. The DC voltage V output by the battery 10 is ｄｃ The SOC of the battery 10 can be measured (acquired) as needed using a sensor (not shown) or the like.

[0011] The electric motor 11 is a drive source of the electric vehicle 100 and is configured by, for example, a three-phase AC synchronous motor. ｍ The torque is transmitted to the drive wheels 15 via a reduction gear and a drive shaft. As a result, a driving force is generated in the electric vehicle 100.

[0012] The power generation system 12 is a system that generates power to charge the battery 10 or to supply power to the electric motor 11. In this embodiment, for simplicity, it is assumed that the power generated by the power generation system 12 is used to charge the battery 10.

[0013] The power generation system 12 is an on-board power generation system and includes an engine 16 and a generator 17. The engine 16 is an internal combustion engine driven by gasoline or other fuel. The generator 17 is connected to the output shaft of the engine 16 and generates electricity using the power input from the engine 16. In this embodiment, the generator 17 rotates at a rotation speed N Ｇ The engine 16 is controlled so that the rotation speed N Ｇ In order to obtain the maximum power generation amount according to the output torque (hereinafter, engine torque T Ｅ Therefore, in this embodiment, the operating state (operating point) of the power generation system 12 is controlled by the rotation speed N Ｇ and engine torque T Ｅ It is determined by:

[0014] When the controller 14 requests the power generation system 12 to generate power, the power generation system 12 generates power in a specific operating state in which the engine 16 has good fuel economy and the power generation system 12 generates little noise and vibration. In other words, the power generation system 12 generates power in an operating state in which the power generation efficiency is at its best. In the following, the rotation speed N Ｇ and engine torque T Ｅ respectively, N Ｇ－ｂｅｓｔ and T Ｅ－ｂｅｓｔ In other words, the best operating condition is when the rotation speed is N Ｇ N Ｇ－ｂｅｓｔ and the engine torque T Ｅ T Ｅ－ｂｅｓｔ This is the state where N Ｇ－ｂｅｓｔ and T Ｅ－ｂｅｓｔ is determined in advance by experiment or simulation depending on the specific configuration of the power generation system 12.

[0015] The power generation system 12 has an SOC lower than a predetermined lower limit SOC Ｌ When the SOC falls below a predetermined upper limit value SOC Ｈ However, if the SOC exceeds the lower limit SOC Ｌ and further falls below a predetermined reference value TH ＬＬ When the reference value TH is below 100 kJ / s, or when there is a risk of this happening, the power generation system 12 increases the amount of power generation above normal, while allowing for a deterioration in fuel efficiency or the generation of noise and vibration. In other words, when it is necessary to restore the SOC and secure driving energy even at the expense of allowing for a deterioration in fuel efficiency or the generation of noise and vibration, the power generation system 12 operates in an operating state other than the operating state that provides the best power generation efficiency. ＬＬ is determined by fitting based on experiments or simulations.

[0016] In addition, the power generation system 12 is configured to detect whether the vehicle speed V of the electric vehicle 100 is a predetermined vehicle speed threshold TH Ｖ When the power generation system 12 is operating, the vehicle speed V is greater than or equal to the vehicle speed threshold TH. ＶWhen the vehicle speed threshold TH is smaller than the threshold TH, the power generation system 12 is stopped in principle. Ｖ is determined in advance by experiment or simulation. The vehicle speed V is, for example, ｍ It can be calculated based on the following.

[0017] The navigation system 13 is a system that provides guidance on travel routes and the like to the driver and other occupants (hereinafter simply referred to as the driver) of the electric vehicle 100. The navigation system 13 provides guidance on one or more travel routes that are optimal in terms of required time, cost, and the like, depending on the current location of the electric vehicle 100 and a destination set by the driver.

[0018] When the driver selects (decides) a route, the navigation system 13 sends information related to the selected route (hereinafter referred to as route information R ＩＮＦＯ The driving route information R ＩＮＦＯ In addition to information about the travel route itself, the travel route information R ＩＮＦＯ It is assumed that the route information includes information on the gradient ψ at each point on the route in addition to information on the route itself.

[0019] However, the gradient ψ can be calculated from the altitude at each point. The air density is essentially determined by the altitude at each point. The predicted vehicle speed is predetermined based on previously collected statistical data, etc., and is the vehicle speed generally expected during travel (general vehicle speed). In addition, the travel route information R ＩＮＦＯ may include predicted values ​​related to the running resistance at each point on the travel route. The running resistance may be calculated based on the vehicle speed (predicted vehicle speed), air density, vehicle weight, and the like.

[0020] Furthermore, when the electric vehicle 100 has traveled the planned travel route in the past, the navigation system 13 may store actual history such as changes in vehicle speed and SOC along the travel route (hereinafter referred to as travel history). In this case, the travel route information R ＩＮＦＯmay include the actual driving history of the electric vehicle 100 instead of or in addition to the predicted vehicle speed, etc.

[0021] Additionally, the navigation system 13 can use a GPS (Global Positioning System) sensor (not shown) or the like to acquire the current position of the electric vehicle 100. The navigation system 13 provides the current position to the controller 14 as appropriate.

[0022] The controller 14 is a control device that comprehensively controls each part of the electric vehicle 100. The controller 14 is configured, for example, by one or more computers, and is programmed to control each part at a predetermined control cycle.

[0023] Specifically, the controller 14 calculates the accelerator operation amount A ｐｏ , the rotation speed ω of the electric motor 11 ｍ , and the DC voltage V of the battery 10 ｄｃ Based on the above, the torque T generated by the electric motor 11 is ｍ Furthermore, the controller 14 controls the operation of the power generation system 12 based on the SOC of the battery 10. In particular, in this embodiment, the controller 14 controls the operation of the power generation system 12 based on the SOC of the battery 10, based on the driving route information R ＩＮＦＯ The operation of the power generation system 12 is controlled by referring to the above.

[0024] 2 is a block diagram showing the configuration of the controller 14. As shown in FIG. 2, the controller 14 includes an uphill section determination unit 21, a vehicle speed limit calculation unit 22, a travel control unit 23, and a power generation control unit 24.

[0025] The uphill section determination unit 21 acquires the travel route of the electric vehicle 100 and determines the uphill sections included in the travel route. In this embodiment, the uphill section determination unit 21 acquires the travel route information R ＩＮＦＯ Then, the uphill section determination unit 21 determines the gradient ψ of the travel route from, for example, a predetermined threshold value TH ψA section where the distance is equal to or greater than this is determined to be an uphill section (uphill road). When there are multiple uphill roads separated by a small flat road or a small downhill road, the uphill section determination unit 21 may determine the entire section including these multiple uphill roads as an uphill section. In other words, the uphill section determination unit 21 may determine a series of sections including one or more uphill roads as an uphill section.

[0026] The vehicle speed limit calculation unit 22 calculates an upper limit value for the vehicle speed V in an uphill section (hereinafter referred to as upper limit vehicle speed V ｌｉｍ Specifically, the vehicle speed limit calculation unit 22 calculates the energy required for traveling on an uphill section (hereinafter referred to as uphill traveling energy E Ｄ ) is calculated, and this climbing energy E Ｄ and the fuel consumption characteristics of the power generation system 12, the upper limit vehicle speed V ｌｉｍ The fuel consumption characteristics of the power generation system 12 are expressed, for example, by the operating state of the power generation system 12. In particular, in this embodiment, the upper limit vehicle speed V ｌｉｍ The fuel consumption characteristics of the power generation system 12 used in the setting are determined based on the operating condition (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ )

[0027] Specifically, the vehicle speed limit calculation unit 22 of this embodiment includes a traveling energy calculation unit 25 , a power generation energy calculation unit 26 , and an upper vehicle speed limit setting unit 27 .

[0028] The traveling energy calculation unit 25 calculates the energy (hereinafter referred to as traveling energy) that is actually consumed when the electric vehicle 100 travels, based on the traveling route and its gradient ψ. In this embodiment, for simplicity, the traveling energy calculation unit 25 calculates the energy required when the electric vehicle 100 travels against the traveling resistance at each point on the traveling route as the traveling energy. As a result, the traveling energy calculation unit 25 can specify the traveling energy of any section on the traveling route. Thereby, in this embodiment, the traveling energy calculation unit 25 calculates the uphill traveling energy E Ｄ Identify.

[0029] The traveling energy is calculated with respect to the vehicle speed V. That is, the traveling energy calculation unit 25 uses the vehicle speed V as a parameter and calculates the traveling energy for each vehicle speed V. Therefore, the uphill traveling energy E Ｄ is also determined according to the vehicle speed V. In the following, the climbing energy E Ｄ The energy amounts are expressed as equivalent power values ​​(kW).

[0030] The traveling energy calculation unit 25 can calculate the traveling energy more accurately by referring to the predicted vehicle speed and air density at each point on the traveling route. Also, when there is a traveling history, the traveling energy calculation unit 25 can calculate the traveling energy more accurately by referring to the traveling history. Furthermore, when calculating the traveling energy, the traveling energy calculation unit 25 can take into account the power consumption of so-called auxiliary equipment such as an air conditioning system.

[0031] The generated energy calculation unit 26 calculates the energy generated by the power generation system 12 through power generation along the travel route (hereinafter referred to as "generated energy"). Furthermore, when a travel history is available, the generated energy calculation unit 26 can calculate a more accurate generated energy by referring to the travel history. In this embodiment, the generated energy calculation unit 26 calculates the generated energy when the power generation system 12 is appropriately driven in an operating state that provides the best power generation efficiency at each point along the travel route. As a result, the generated energy calculation unit 26 can identify the generated energy at any section along the travel route. In this embodiment, the generated energy calculation unit 26 thereby calculates the generated energy in an uphill section (hereinafter referred to as "uphill generated energy E"). Ｇ Identify the

[0032] The generated energy is calculated for each vehicle speed V, similar to the traveling energy. That is, the generated energy calculation unit 26 uses the vehicle speed V as a parameter and calculates the generated energy for each vehicle speed V. Therefore, the hill-climbing generated energy E Ｇ is also determined according to the vehicle speed V.

[0033] The upper limit vehicle speed setting unit 27 sets the upper limit vehicle speed V of the electric vehicle 100 in an uphill section. ｌｉｍIn this embodiment, the climbing energy E Ｄ and Tosaka Power Generation Energy E Ｇ Based on the balance of ｌｉｍ Set.

[0034] In principle, the driving control unit 23 determines the accelerator operation amount A ｐｏ , the rotation speed ω of the electric motor 11 ｍ , and the DC voltage V of the battery 10 ｄｃ Based on the above, the torque T generated by the electric motor 11 is ｍ However, when the electric vehicle 100 travels on an uphill section, the travel control unit 23 controls the upper limit vehicle speed V ｌｉｍ The torque T generated by the electric motor 11 in response to ｍ As a result, the travel control unit 23 limits the vehicle speed V in the uphill section to the upper limit vehicle speed V ｌｉｍ The travel control unit 23 can determine whether the electric vehicle 100 is traveling on an uphill section based on the travel route and the current position of the electric vehicle 100.

[0035] The power generation control unit 24 starts or stops power generation by the power generation system 12 based on the SOC of the battery 10 and the vehicle speed V of the electric vehicle 100. Specifically, when the SOC is below a predetermined lower limit SOC Ｌ and the vehicle speed V is less than the vehicle speed threshold TH Ｖ When the SOC reaches or exceeds the upper limit value SOC , the power generation control unit 24 starts power generation by the power generation system 12. Ｈ or when the vehicle speed V exceeds the vehicle speed threshold TH Ｖ When the voltage Vcc becomes smaller than the reference voltage Vcc, the power generation system 12 is terminated (stopped).

[0036] In addition, in some sections of the travel route, the power generation control unit 24 Ｌ and upper limit SOC Ｈ In other words, the power generation control unit 24 may change the conditions for starting or stopping power generation depending on the specific conditions of the travel route. In this embodiment, the power generation control unit 24 temporarily changes the predetermined range determined by the lower limit SOC ＬLower the upper limit SOC Ｈ By raising the value, the predetermined range is expanded.

[0037] FIG. 3 shows the driving energy in an uphill section (uphill driving energy E Ｄ ) and power generation energy (climbing power generation energy E Ｇ 3, as the vehicle speed V increases, the climbing energy E Ｄ This is due to an increase in air resistance. On the other hand, when the vehicle speed V increases, the hill-climbing power generation energy E Ｇ This is because, when the vehicle speed V increases, the time spent traveling uphill (hereinafter referred to as traveling time RT) decreases, and it becomes impossible to ensure sufficient power generation time while traveling uphill. As shown in FIG. 3, the climbing traveling energy E Ｄ and Tosaka Power Generation Energy E Ｇ When comparing these, the vehicle speed V Ｂ Therefore, for example, if the vehicle speed is V Ｂ If you drive at the following speed, the amount of power generated during the uphill section will be E Ｇ The climbing energy E Ｄ Therefore, the upper limit vehicle speed setting unit 27 can, for example, cover all of the uphill traveling energy E Ｄ and Tosaka Power Generation Energy E Ｇ The vehicle speed V that balances Ｂ The upper limit vehicle speed V ｌｉｍ However, in this embodiment, the upper limit vehicle speed setting unit 27 determines whether the SOC is greater than the reference value TH ＬＬ A moderate upper limit vehicle speed V ｌｉｍ Set.

[0038] FIG. 4 shows the driving energy in an uphill section (uphill driving energy E Ｄ ) and power generation energy (climbing power generation energy E Ｇ 4A is an explanatory diagram showing the balance of vehicle speed V Ｂ Vehicle speed V is greater than １ (See Figure 3) Ｄ－Ｖ１ , Tosaka Power Generation Energy E Ｇ－Ｖ１, and their balance (-ΔE Ｖ１ ) is shown in FIG. １ Vehicle speed V is even greater than ２ (See Figure 3) Ｄ－Ｖ２ , Tosaka Power Generation Energy E Ｇ－Ｖ２ , and their balance (-ΔE Ｖ２ ) is shown.

[0039] As shown in FIG. 4(A) and FIG. 4(B), the vehicle speed V Ｂ Vehicle speed exceeding V １ , V ２ When the vehicle travels uphill, the energy balance is negative in both cases. The greater the vehicle speed V, the greater the negative energy balance becomes.

[0040] 5 is an explanatory diagram showing the SOC after traveling on an uphill section. As shown in FIG. 5, the SOC at the start of traveling on an uphill section is expressed as the initial SOC ｉｎｉ Then, the vehicle speed V Ｂ When the vehicle runs on an uphill section, the SOC is the initial SOC after the uphill section. ｉｎｉ The vehicle speed V Ｂ Vehicle speed exceeding V １ , V ２ When driving uphill, the energy balance (-ΔE Ｖ１ , −ΔE Ｖ２ ) after traveling uphill, the SOC decreases.

[0041] Here, the uphill section is run at a vehicle speed of V １ When driving at the standard value TH ＬＬ Therefore, the vehicle speed V １ When traveling at high speed, the power generation system 12 can be operated under the best operating conditions.

[0042] On the other hand, the vehicle speed V ２ When driving at the standard value TH ＬＬ Therefore, the vehicle speed in the uphill section is V ２When traveling at a vehicle speed V, it is necessary to secure energy for traveling, even if it means allowing for a decrease in fuel efficiency or the generation of noise and vibration. Therefore, the power generation control unit 24 operates the power generation system 12 in an operating condition other than the best operating condition while traveling on an uphill section. This allows the power generation system 12 to operate at least at a vehicle speed V ２ SOC and reference value TH after driving uphill ＬＬ The difference between (+δE Ｇ ) will be compensated for.

[0043] And the vehicle speed V １ and vehicle speed V ２ During this time, the SOC after driving uphill is equal to the reference value TH. ＬＬ Therefore, in this embodiment, the upper limit vehicle speed setting unit 27 sets this vehicle speed as the upper limit vehicle speed V ｌｉｍ Specifically, the upper limit vehicle speed setting unit 27 sets the uphill traveling energy E Ｄ and climbing energy E Ｇ The energy balance of the initial SOC ｉｎｉ and the reference value TH ＬＬ The energy balance (-ΔE ｌｉｍ ) is the upper limit vehicle speed V ｌｉｍ This upper limit vehicle speed V ｌｉｍ If the vehicle travels uphill at a vehicle speed V limited to the following, the SOC will be equal to or less than the reference value TH ＬＬ It is maintained above that.

[0044] The operation of the vehicle speed limit control in the electric vehicle 100 configured as described above will now be described.

[0045] 6 is a flowchart of the vehicle speed limit control. As shown in FIG. 6, in step S10, the uphill section determination unit 21 determines whether there is an uphill section in the travel route. In step S11, the travel energy calculation unit 25 calculates the travel energy according to the travel route, and in particular, the uphill travel energy E Ｄ In step S12, the power generation energy calculation unit 26 calculates the power generation energy according to the travel route, and in particular, determines the uphill power generation energy E Ｇ Then, in step S13, the upper limit vehicle speed setting unit 27 determines the uphill traveling energy EＤ and Tosaka Power Generation Energy E Ｇ Based on the balance of ｌｉｍ Set.

[0046] Thereafter, in step S14, the traveling control unit 23 determines whether the electric vehicle 100 is traveling on an uphill section based on the traveling route and the current position. When it is determined in step S14 that the electric vehicle 100 is traveling on an uphill section, the process proceeds to step S15, and the traveling control unit 23 sets the vehicle speed V to the upper limit vehicle speed V ｌｉｍ Limited to the following (V≦V ｌｉｍ ). This ensures the travel time RT for the uphill section, and provides ample time for the power generation system 12 to generate the required amount of power in the best operating condition while traveling uphill. This allows the electric vehicle 100 to get through the uphill section without generating power in an operating condition that would result in poor fuel economy or that is likely to produce noise or vibration.

[0047] In step S14, when it is determined that the electric vehicle 100 is not traveling in an uphill section, the traveling control unit 23 sets the upper limit vehicle speed V ｌｉｍ In other words, when the electric vehicle 100 is traveling on a flat road or the like, the vehicle speed V is not limited.

[0048] 7A to 7D are graphs showing the transition of the SOC and other parameters when traveling uphill. Ｇ , engine torque T Ｅ 7 shows the transition of the upper limit vehicle speed V in the uphill section. ｌｉｍ This is an example in which the speed limit is not imposed by time t １ is the time when the electric vehicle 100 reaches the start point of the uphill section from the flat road, and time t ２ is the time when the electric vehicle 100 reaches the end point of the uphill section in the comparative example, and time t3 is the time when the electric vehicle 100 reaches the end point of the uphill section in this embodiment.

[0049] As shown in FIGS. 7A to 7D, when the vehicle is traveling on a flat road, the upper limit vehicle speed V ｌｉｍSince the vehicle speed is not limited by the above, the transition of each parameter is almost the same between the comparative example and this embodiment.

[0050] On the other hand, at time t １ When the electric vehicle 100 reaches an uphill section, as shown in FIG. 7A, in this embodiment, the vehicle speed V reaches the upper limit vehicle speed V ｌｉｍ In this case, in a comparative example in which the vehicle speed is not limited, the electric vehicle 100 reaches the speed at time t ２ In contrast, in this embodiment, the electric vehicle 100 arrives at the end point of the uphill section at time t ３ In other words, in the comparative example, the running time RT of the uphill section is Δt ２１ = t ２ -t １ However, in this embodiment, the running time RT in the uphill section is Δt ３１ = t ３ -t １ stretches to.

[0051] At this time, in the comparative example, at time t １ Since the vehicle speed V is not restricted thereafter, the climbing energy E Ｄ and Tosaka Power Generation Energy E Ｇ Due to the negative balance, the SOC is below the reference value TH. ＬＬ Therefore, as shown by the dashed lines in Fig. 7B and Fig. 7C, in the comparative example, the power generation system 12 is appropriately set to the best operating state (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ As a result, in the comparative example, fuel economy deteriorates or noise and vibration occur during driving on an uphill section, but as shown by the broken line in FIG. 7(D), the vehicle is driven in a driving state that deviates from the reference value TH ＬＬ The SOC is maintained so as not to fall below this.

[0052] On the other hand, in this embodiment, the driving time RT in the uphill section is extended due to the vehicle speed limit, and therefore the total time for power generation that is appropriately performed while driving in the uphill section is also extended. Therefore, as shown by the solid lines in Figures 7(B) and 7(C), in this embodiment, when driving the power generation system 12 in the uphill section, the best operating state (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ), as shown by the solid line in FIG. 7(D), the SOC remains below the reference value TH ＬＬ That is, in this embodiment, the vehicle speed V is maintained at a value greater than the upper limit vehicle speed V ｌｉｍ By limiting the driving time RT in the uphill section to the following value and extending the driving time RT in the uphill section, sufficient power generation time is ensured while driving the uphill section. As a result, the electric vehicle 100 can get through the uphill section by appropriately driving the power generation system 12 in the best operating condition. Therefore, the electric vehicle 100 of this embodiment has improved fuel efficiency and reduced noise and vibration compared to the comparative example.

[0053] [Second embodiment] In the second embodiment, the upper limit vehicle speed V is calculated in a manner different from that in the first embodiment. ｌｉｍ By rationally and appropriately setting N, the best driving condition (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ This section explains an example of how to get by by generating electricity using electricity generated from a power source.

[0054] 8 is a block diagram showing the configuration of the controller 14 according to the second embodiment. As shown in FIG. 8, the controller 14 according to the second embodiment differs from the first embodiment in the configuration of the vehicle speed limit calculation unit 22. Specifically, the controller 14 according to the second embodiment includes a fuel consumption calculation unit 30 instead of the power generation energy calculation unit 26. This allows the upper limit vehicle speed setting unit 27 to set the upper limit vehicle speed V ｌｉｍ The specific method for setting the value is different from that of the first embodiment. The other configurations are the same as those of the first embodiment.

[0055] The fuel consumption calculation unit 30 calculates the traveling energy (climbing traveling energy E Ｄ ), the fuel consumption rate of the power generation system 12 on the travel route (hereinafter referred to as the fuel consumption rate R ＦＣ The fuel consumption rate R ＦＣ For example, the break-even fuel consumption (BSFC) of the engine 16 can be used as the fuel consumption amount. In this embodiment, the fuel consumption amount calculation unit 30 calculates the fuel consumption rate R ＦＣ Therefore, the fuel consumption calculation unit 30 calculates the fuel consumption rate R ＦＣIn this embodiment, the fuel consumption calculation unit 30 can determine the total fuel consumption in the uphill section (hereinafter referred to as the uphill fuel consumption T ＦＣ Identify the

[0056] The fuel consumption rate R ＦＣ is calculated for the vehicle speed V, similarly to the traveling energy etc. In other words, the fuel consumption calculation unit 30 uses the vehicle speed V as a parameter and calculates the fuel consumption rate R ＦＣ Therefore, the amount of fuel consumed for climbing T ＦＣ is also determined according to the vehicle speed V.

[0057] The upper limit vehicle speed setting unit 27 sets the upper limit vehicle speed V of the electric vehicle 100 in an uphill section. ｌｉｍ This is the same as in the first embodiment. However, in this embodiment, the upper limit vehicle speed setting unit 27 sets the uphill fuel consumption T ＦＣ and the travel time RT of the uphill section, the upper limit vehicle speed V ｌｉｍ That is, in this embodiment, the upper limit vehicle speed V ｌｉｍ The fuel consumption characteristics of the power generation system 12 used in setting the fuel consumption rate R ＦＣ , uphill fuel consumption T ＦＣ , or both.

[0058] Specifically, the upper limit vehicle speed setting unit 27 calculates the uphill fuel consumption T ＦＣ and a predetermined evaluation function f(T ＦＣ , RT), an evaluation value S for the vehicle speed V is calculated. Then, the upper limit vehicle speed V is calculated based on this evaluation value S. ｌｉｍ Set.

[0059] Evaluation function f(T ＦＣ , RT) is, for example, the climbing fuel consumption T ＦＣ and the travel time RT, or a function formed by combining these. ＦＣ , RT) is the climbing fuel consumption T ＦＣ and the travel time RT. That is, in this embodiment, the evaluation function f(T ＦＣ, RT) is calculated by using a weighting coefficient α (0<α<1) as ＦＣ , RT) = αT ＦＣ +(1-α)RT.

[0060] In this embodiment, for simplicity, it is assumed that the weighting coefficient α is predetermined by experiment or simulation, but the weighting coefficient α can be a variable parameter.

[0061] FIG. 9 shows the fuel consumption F according to the vehicle speed V. Ｃ 9A is an explanatory diagram showing the calculation of the uphill traveling energy E with respect to the vehicle speed V. Ｄ In FIG. 9A, the uphill running energy E Ｄ 9B shows an example of the output P Ｇ [kW] vs. fuel consumption F Ｃ The line connecting the operating points where N is lowest (so-called α line of the engine 16) is shown. Note that the operating points indicated by stars in FIG. 9B are the best operating conditions (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ ) is the operating point corresponding to

[0062] As shown in FIG. 9A, the traveling energy calculation unit 25 calculates the uphill traveling energy E for each vehicle speed V according to the gradient ψ of the uphill section. Ｄ Here, in particular, the climbing energy E for a certain vehicle speed V' is calculated. Ｄ ' is calculated.

[0063] Then, the fuel consumption calculation unit 30 calculates the uphill traveling energy E Ｄ Output P that balances with Ｇ Minimum fuel consumption when operating at F Ｃ That is, the fuel consumption calculation unit 30 calculates E Ｄ =P Ｇ The fuel consumption when Ｃ As a result, the fuel consumption calculation unit 30 calculates the minimum fuel consumption F corresponding to the vehicle speed V. Ｃ In this way, the fuel consumption FＣ , the fuel consumption calculation unit 30 calculates the fuel consumption F Ｃ By summing these for each vehicle speed V, the climbing fuel consumption TF Ｃ In FIG. 9B, the uphill running energy E Ｄ Output P equal to Ｇ The minimum fuel consumption F when the power generation system 12 is operated at Ｃ ' is calculated.

[0064] FIG. 10 shows the fuel consumption in the uphill section (uphill fuel consumption T ＦＣ 10 is a graph showing the amount of fuel consumed for climbing TF relative to the vehicle speed V. Ｃ is represented by a solid line, and the traveling time RT in the uphill section relative to the vehicle speed V is represented by a dashed line.

[0065] As shown by the dashed line in FIG. 10, the travel time RT in the uphill section decreases according to the vehicle speed V. On the other hand, as shown by the solid line, the uphill fuel consumption T ＦＣ decreases in accordance with the vehicle speed V when the vehicle speed V is low, but increases in accordance with the vehicle speed V when the vehicle speed V is high. ＦＣ , RT) changes depending on the vehicle speed V and has a peak (maximum value) or a bottom (minimum value). Therefore, the upper limit vehicle speed setting unit 27 sets the vehicle speed V at which the evaluation value S reaches its peak or bottom as the upper limit vehicle speed V. ｌｉｍ can be set to.

[0066] FIG. 11 is a graph showing the evaluation value S according to the vehicle speed V. Here, the evaluation value S is calculated based on the uphill fuel consumption T ＦＣ 11, the evaluation value S has a bottom (minimum value). Therefore, the upper limit vehicle speed setting unit 27 sets the vehicle speed V at which the evaluation value S based on the weighted sum is minimum as the upper limit vehicle speed V. ｌｉｍ This upper limit vehicle speed V ｌｉｍ is the climbing fuel consumption T ＦＣ and the travel time RT are optimized. ｌｉｍ If the vehicle speed V is limited in the uphill section as follows, the uphill fuel consumption T can be reduced without making the travel time RT too long.ＦＣ is reduced.

[0067] 12 is a flowchart of the vehicle speed limit control according to the second embodiment. As shown in FIG. 12, in step S20, the uphill section determination unit 21 determines an uphill section on the travel route. In step S21, the travel energy calculation unit 25 calculates the travel energy according to the travel route, and in particular, the uphill travel energy E Ｄ In step S22, the fuel consumption calculation unit 30 determines the uphill traveling energy E Ｄ Based on the fuel consumption rate R ＦＣ is calculated, and then the amount of fuel consumed for climbing T ＦＣ In step S23, the upper limit vehicle speed setting unit 27 determines a predetermined evaluation function f(T ＦＣ , RT) to calculate the climbing fuel consumption T ＦＣ and the travel time RT, an evaluation value S for the vehicle speed V is calculated. Then, in step S24, the upper limit vehicle speed setting unit 27 calculates the upper limit vehicle speed V based on the evaluation value S. ｌｉｍ Set.

[0068] Thereafter, in step S25, the traveling control unit 23 determines whether the electric vehicle 100 is traveling on an uphill section based on the traveling route and the current position. When it is determined in step S25 that the electric vehicle 100 is traveling on an uphill section, the process proceeds to step S26, and the traveling control unit 23 sets the vehicle speed V to the upper limit vehicle speed V ｌｉｍ Limited to the following (V≦V ｌｉｍ ). This ensures the travel time RT for the uphill section, and provides ample time for the power generation system 12 to generate the required amount of power in the best operating condition while traveling uphill. This allows the electric vehicle 100 to get through the uphill section without generating power in an operating condition that would result in poor fuel economy or that is likely to produce noise or vibration.

[0069] When it is determined in step S25 that the electric vehicle 100 is not traveling in an uphill section, the traveling control unit 23 sets the upper limit vehicle speed V ｌｉｍ In other words, when the electric vehicle 100 is traveling on a flat road or the like, the vehicle speed V is not limited.

[0070] As described above, in the vehicle speed limit control of the second embodiment, the uphill fuel consumption T ＦＣ Using the evaluation value S based on the travel time RT, the upper limit vehicle speed V in the uphill section is calculated. ｌｉｍ This sets the climbing fuel consumption T ＦＣ The balance between the running time RT and the running time RT is optimized, and the running time RT in the uphill section is not extended too much, and the uphill fuel consumption T ＦＣ is reduced.

[0071] [Modification] In the second embodiment, for simplicity, the evaluation function f(T ＦＣ , RT) is a predetermined fixed value, but it is preferable that the weighting coefficient α is variable.

[0072] When the weighting coefficient α is a variable parameter, it is preferable that the weighting coefficient α can be arbitrarily adjusted by a setting operation by the driver, such as a mode selection operation. This allows the behavior of the electric vehicle 100 to be adjusted according to the driver's preference. For example, when the driver places importance on fuel economy, noise, or vibration suppression, the evaluation function f(T ＦＣ , RT) Climbing fuel consumption T ＦＣ By relatively increasing the weight of , this preference is reflected in the upper limit vehicle speed V ｌｉｍ In addition, when the driver wishes to shorten the travel time RT in the uphill section, accepting a deterioration in fuel economy or the generation of noise and vibration to some extent, the evaluation function f(T ＦＣ , RT), this preference is reflected in the upper limit vehicle speed V ｌｉｍ is reflected in.

[0073] When the weighting coefficient α is a variable parameter, the upper limit vehicle speed setting unit 27 can automatically adjust the weighting coefficient α. For example, when there is a driving history for the driving route, the upper limit vehicle speed setting unit 27 can automatically adjust the weighting coefficient α based on the difference between the predicted vehicle speed on the driving route and the vehicle speed V in the actual driving history. Specifically, when the vehicle speed V in the driving history is greater than the predicted vehicle speed, the upper limit vehicle speed setting unit 27 determines that the driver places importance on shortening the driving time RT, and automatically adjusts the evaluation function f(TＦＣ On the other hand, when the vehicle speed V in the driving history is smaller than the predicted vehicle speed, the upper limit vehicle speed setting unit 27 determines that the driver is willing to extend the driving time RT or is prioritizing fuel economy, noise, or vibration suppression, and automatically adjusts the evaluation function f(T ＦＣ , RT) Climbing fuel consumption T ＦＣ In this way, when the weighting coefficient α is automatically adjusted based on the difference between the predicted vehicle speed and the vehicle speed V in the travel history, the upper limit vehicle speed setting unit 27 can set a specific value of the weighting coefficient α depending on the magnitude of the difference between the predicted vehicle speed and the vehicle speed V in the travel history.

[0074] In the first and second embodiments, the uphill section determination unit 21 determines whether the gradient ψ is greater than the predetermined threshold value TH ψ However, the method of determining whether an uphill section is an uphill section is not limited to this. The traveling energy calculation unit 25 calculates the traveling energy taking into consideration the gradient ψ of the traveling route, so the uphill section determination unit 21 can determine whether an uphill section is an uphill section based on the traveling energy. Specifically, the uphill section determination unit 21 determines whether the traveling energy is greater than or equal to a predetermined threshold TH Ｄ Furthermore, when the traveling energy calculation unit 25 calculates the traveling energy based on the traveling history of the traveling route, the uphill section determination unit 21 also determines whether the traveling energy is equal to or greater than a predetermined threshold TH Ｄ A section where this is the case or more can be determined to be an uphill section.

[0075] In the first and second embodiments, the upper limit vehicle speed V in an uphill section is calculated using a predetermined fuel consumption characteristic of the power generation system 12. ｌｉｍ is set, but is not limited to this. It is preferable that the fuel consumption characteristics of the power generation system 12 be adjusted (corrected) according to the specific environment when traveling along the travel route. For example, the fuel consumption characteristics of the power generation system 12 may change depending on the outside air temperature, altitude, air density, and the water temperature of the engine 16. For this reason, the upper limit vehicle speed V ｌｉｍWhen setting the optimum operating condition (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ In the second embodiment, it is preferable to adjust the fuel consumption rate R ＦＣ It is preferable to adjust it depending on the actual environment.

[0076] In the first and second embodiments, regardless of whether the driver accepts the vehicle speed limit or not, the vehicle speed V is set to the upper limit vehicle speed V ｌｉｍ The vehicle speed V is limited to, but not limited to, the upper limit vehicle speed V ｌｉｍ It is preferable to notify the driver that the vehicle speed V will be limited to a value below this value, and to limit the vehicle speed V only when the driver accepts this through a setting operation such as a mode setting.

[0077] In the first and second embodiments described above, it is assumed that the driver is operating the electric vehicle 100, but this is not limiting. That is, when the electric vehicle 100 is in an autonomous driving state, the controller 14 sets the target vehicle speed for autonomous driving in an uphill section to the upper limit vehicle speed V ｌｉｍ can be set to.

[0078] In addition, it is preferable that the vehicle speed limit control according to the first and second embodiments be performed not only in uphill sections, but also in other sections where high-load driving is expected.

[0079] As described above, the control method for an electric vehicle according to the first embodiment, the second embodiment, and the modified example is a control method for an electric vehicle 100 that charges the battery 10 using the on-board power generation system 12. In this control method, a travel route of the electric vehicle 100 is acquired, an uphill section included in the travel route is determined, and the travel energy required for travel on the uphill section (uphill travel energy E Ｄ ) and calculate the running energy (E Ｄ ) and the fuel consumption characteristics of the power generation system 12, ｌｉｍThen, when traveling on an uphill section, the vehicle speed V is set to the upper limit vehicle speed V ｌｉｍ Restrict to the following:

[0080] In this way, the upper limit vehicle speed V ｌｉｍ and set the vehicle speed V in the uphill section to the upper limit vehicle speed V ｌｉｍ If the driving time is limited to the following, the driving time RT in the uphill section is ensured. Therefore, the power generation time in the uphill section increases, and as a result, the amount of power generated also increases. Therefore, the electric vehicle 100 can be driven in the best driving condition (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ In other words, fuel economy is improved and noise and vibration are suppressed compared to when no speed limit is imposed on the uphill section.

[0081] In the control method for an electric vehicle according to the first embodiment and the modified example, the power generation energy in an uphill section (uphill power generation energy E Ｇ ) and calculate the driving energy (E Ｄ ) and the generated energy (E Ｇ ) based on the balance of the upper limit vehicle speed V ｌｉｍ Set.

[0082] In this way, the driving energy (E Ｄ ) and generated energy (E Ｇ ) based on the balance of the upper limit vehicle speed V ｌｉｍ When this is set, the upper limit vehicle speed V ｌｉｍ In other words, fuel economy and the like can be improved without excessively lengthening the travel time RT in the uphill section.

[0083] In the control method for an electric vehicle according to the first embodiment and the modified example, the fuel consumption characteristics of the power generation system 12 are specifically determined based on the operating state (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ ) and the upper limit vehicle speed V ｌｉｍ is the driving energy (E Ｇ ) and the operating state where power generation efficiency is best (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ) when the power generation system 12 is operated at Ｇ ) and is set based on the balance of income and expenditure.

[0084] In this way, the fuel consumption characteristics of the power generation system 12 are determined by the operating state (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ ) to generate power (E Ｇ ) is calculated, the upper limit vehicle speed V ｌｉｍ In other words, fuel economy and the like can be improved without excessively lengthening the travel time RT in the uphill section.

[0085] In the control method for an electric vehicle according to the second embodiment and the modified example, the running energy (climbing running energy E Ｄ ) and the fuel consumption characteristics of the power generation system 12, the fuel consumption of the power generation system 12 in the uphill section (uphill fuel consumption T ＦＣ ) is calculated, and the travel time RT of the uphill section is calculated for each vehicle speed V, and the fuel consumption (T ＦＣ ) and the running time RT as inputs. ＦＣ , RT), an evaluation value S for the vehicle speed V is calculated. Then, the upper limit vehicle speed V is calculated based on the evaluation value S. ｌｉｍ Set.

[0086] In this way, the fuel consumption (T ＦＣ ) and the travel time RT as inputs to the evaluation function f(T ＦＣ , RT) based on the evaluation value S calculated by ｌｉｍ When this is set, the upper limit vehicle speed V ｌｉｍ In other words, fuel economy and the like can be improved without excessively lengthening the travel time RT in the uphill section. In particular, this method ＦＣ ) and the running time RT can be easily optimized.

[0087] In the control method for an electric vehicle according to the second embodiment and the modified example, the fuel consumption (T ＦＣ ) is specifically the driving energy (E Ｄ ) and the output P of the power generation system 12 Ｇ The fuel consumption rate R when ＦＣIt is calculated using

[0088] In this way, the climbing energy E Ｄ and the output P of the power generation system 12 Ｇ The fuel consumption rate R when ＦＣ Using this, the climbing fuel consumption T ＦＣ When the upper limit vehicle speed V ｌｉｍ In other words, fuel economy and the like can be improved without excessively lengthening the travel time RT in the uphill section.

[0089] In the control method for an electric vehicle according to the modified example of the second embodiment, the evaluation function f(T ＦＣ , RT) is the fuel consumption (T ＦＣ ) and the travel time RT, and the evaluation value S is calculated by the weighted sum of the fuel consumption (T ＦＣ ) and the weighting coefficient α for the travel time RT are variable.

[0090] In this way, the evaluation function f(T ＦＣ , RT) is variable, the driver's preference regarding fuel economy and travel time RT is ｌｉｍ Therefore, fuel economy and the like in uphill sections can be improved without damaging the driver's expectations.

[0091] In the control method for an electric vehicle according to the modified example of the second embodiment, the weighting coefficient α is set by the driver.

[0092] In this way, when the driver directly adjusts the weighting coefficient α by operating the mode setting or the like, the driver's preference regarding fuel economy and the running time RT is reliably adjusted to the upper limit vehicle speed V ｌｉｍ Therefore, fuel economy and the like in uphill sections can be improved without damaging the driver's expectations.

[0093] In the control method for an electric vehicle according to the modified example of the second embodiment, the weighting coefficient α is automatically set based on the difference between the predicted vehicle speed on a predetermined travel route and the vehicle speed V in the actual travel history.

[0094] In this way, if the weighting coefficient α is automatically set, the driver's preferences regarding fuel economy and the driving time RT can be reflected in the upper limit vehicle speed V without the driver having to directly set the coefficient. ｌｉｍ can be reflected in.

[0095] In the control method for an electric vehicle according to the modified example of the first embodiment and the second embodiment, the traveling energy is calculated based on the gradient ψ of the traveling route, and the traveling energy is calculated based on the predetermined threshold TH Ｄ A section where this is the case or more is determined to be an uphill section.

[0096] In this way, if the travel energy of the travel route is used, the upper limit vehicle speed V ｌｉｍ This makes it possible to accurately determine the uphill section where the vehicle speed should be limited.

[0097] In the control method for an electric vehicle according to the modified example of the first embodiment and the second embodiment, the traveling energy is calculated based on the traveling history of the traveling route, and the traveling energy is calculated based on the predetermined threshold value TH Ｄ A section where this is the case or more is determined to be an uphill section.

[0098] In this way, when calculating the travel energy based on the travel history, if the travel energy of the travel route is used, the upper limit vehicle speed V ｌｉｍ This makes it possible to accurately determine the uphill section where the vehicle speed V should be limited. Furthermore, by determining the uphill section using the traveling energy calculated based on the traveling history in this way, even if the traveling route is not set in the navigation system 13, it is possible to predict the uphill section where the vehicle speed V should be limited, thereby improving fuel efficiency, etc.

[0099] In the control methods for the electric vehicle according to the modifications of the first and second embodiments, the fuel consumption characteristics of the power generation system 12 are adjusted in accordance with the environment when traveling along a travel route.

[0100] In this way, by adjusting (correcting) the fuel consumption characteristics of the power generation system 12 in accordance with the environment of the travel route, such as the outside air temperature, altitude, air density, and water temperature of the engine 16, an appropriate upper limit vehicle speed V ｌｉｍ Therefore, fuel economy and the like can be improved without excessively lengthening the travel time RT in the uphill section.

[0101] In the control method for an electric vehicle according to the modified example of the first embodiment and the second embodiment, the vehicle speed V is set to an upper limit vehicle speed V ｌｉｍ The driver is notified that the vehicle speed V will be limited to the value below, and when the driver allows it through a setting operation, the vehicle speed V is limited.

[0102] In this way, by limiting the vehicle speed V in an uphill section only when the driver allows it, fuel economy and the like in an uphill section can be improved without damaging the driver's expectations.

[0103] In the control method for an electric vehicle according to the modified example of the first embodiment and the second embodiment, when the electric vehicle 100 is in autonomous driving, the target vehicle speed in an uphill section is set to the upper limit vehicle speed V ｌｉｍ Set to.

[0104] In this way, the target vehicle speed for autonomous driving in an uphill section is set to the upper limit vehicle speed V ｌｉｍ If the setting is made as above, fuel efficiency and the like in uphill sections can be improved even when the electric vehicle 100 is in autonomous driving.

[0105] The control device for an electric vehicle according to the first embodiment, the second embodiment, and the modified example is a control device (controller 14) for an electric vehicle 100 that charges a battery 10 using an on-board power generation system 12. This control device (controller 14) includes an uphill section determination unit 21 that acquires a travel route for the electric vehicle 100 and determines uphill sections included in the travel route, and a travel energy determination unit 22 that determines the travel energy required for travel on the uphill sections (uphill travel energy E Ｄ ) and a running energy calculation unit 25 that calculates the running energy (E Ｄ ) and the fuel consumption characteristics of the power generation system 12, ｌｉｍ and an upper limit vehicle speed setting unit 27 that sets the vehicle speed V to the upper limit vehicle speed V when traveling on an uphill section. ｌｉｍ and a driving control unit 23 that restricts the following:

[0106] In this way, the upper limit vehicle speed V ｌｉｍ and set the vehicle speed V in the uphill section to the upper limit vehicle speed V ｌｉｍIf the driving time is limited to the following, the driving time RT in the uphill section is ensured. Therefore, the power generation time in the uphill section increases, and as a result, the amount of power generated also increases. Therefore, the electric vehicle 100 can be driven in the best driving condition (N Ｇ－ｂｅｓｔ , T Ｅ－ｂｅｓｔ In other words, fuel economy is improved and noise and vibration are suppressed compared to when no speed limit is imposed on the uphill section.

[0107] The above describes embodiments and modifications of the present invention, but the configurations described in the above embodiments and modifications merely illustrate some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

[0108] For example, in the above embodiment, the electric vehicle 100 is a series hybrid vehicle, but the present invention is also suitable for electric vehicles other than series hybrid vehicles as long as the electric vehicle 100 is equipped with a power generation system 12.

Claims

1. A control method for an electric vehicle that charges a battery using an on-board power generation system, comprising: acquiring a driving route for the electric vehicle; determining an uphill section included in the driving route; calculating the driving energy required for driving on the uphill section; setting an upper limit vehicle speed based on the driving energy and the fuel consumption characteristics of the power generation system; and limiting the vehicle speed to be equal to or less than the upper limit vehicle speed when driving on the uphill section.

2. A control method for an electric vehicle as claimed in claim 1, comprising: calculating the power generation energy in the uphill section based on the fuel consumption characteristics of the power generation system; and setting the upper limit vehicle speed based on the balance between the driving energy and the power generation energy.

3. A control method for an electric vehicle as set forth in claim 2, wherein the fuel consumption characteristics of the power generation system are represented by an operating state in which power generation efficiency is at its best, and the upper limit vehicle speed is set based on the balance between the driving energy and the generated energy when the power generation system is operated in the operating state in which power generation efficiency is at its best.

4. A control method for an electric vehicle as claimed in claim 1, comprising: calculating the fuel consumption of the power generation system in the uphill section for each vehicle speed based on the running energy and the fuel consumption characteristics of the power generation system; calculating the driving time in the uphill section for each vehicle speed; calculating an evaluation value for the vehicle speed using a predetermined evaluation function that takes as input the fuel consumption and the driving time; and setting the upper limit vehicle speed based on the evaluation value.

5. A control method for an electric vehicle according to claim 4, wherein the fuel consumption amount is calculated using a fuel consumption rate when the running energy and the output of the power generation system are in balance.

6. A control method for an electric vehicle according to claim 4, wherein the evaluation function is a function that calculates the evaluation value by a weighted sum of the fuel consumption amount and the running time, and the weighting coefficients for the fuel consumption amount and the running time are variable.

7. A control method for an electric vehicle according to claim 6, wherein the weighting coefficient is set by a driver.

8. A control method for an electric vehicle according to claim 6, wherein the weighting coefficient is automatically set based on the difference between a predicted vehicle speed on the predetermined travel route and the vehicle speed in the actual travel history.

9. A control method for an electric vehicle according to any one of claims 1 to 8, wherein the driving energy is calculated based on the gradient of the driving route, and a section where the driving energy is equal to or greater than a predetermined threshold is determined to be the uphill section.

10. A control method for an electric vehicle according to any one of claims 1 to 8, wherein the traveling energy is calculated based on the traveling history of the traveling route, and a section where the traveling energy is equal to or greater than a predetermined threshold is determined to be the uphill section.

11. A control method for an electric vehicle according to any one of claims 1 to 8, wherein the fuel consumption characteristics of the power generation system are adjusted in accordance with the environment when the vehicle is traveling along the travel route.

12. A control method for an electric vehicle according to any one of claims 1 to 8, wherein the driver is notified that the vehicle speed will be limited to or below the upper limit vehicle speed, and the vehicle speed is limited when the driver allows it through a setting operation.

13. A control method for an electric vehicle according to any one of claims 1 to 8, wherein when the electric vehicle is in autonomous driving, the target vehicle speed in the uphill section is set to the upper limit vehicle speed.

14. A control device for an electric vehicle that charges a battery using an on-board power generation system, comprising: an uphill section determination unit that acquires a driving route of the electric vehicle and determines uphill sections included in the driving route; a driving energy calculation unit that calculates the driving energy required for driving on the uphill section; an upper limit vehicle speed setting unit that sets an upper limit vehicle speed based on the driving energy and the fuel consumption characteristics of the power generation system; and a driving control unit that limits the vehicle speed to less than or equal to the upper limit vehicle speed when driving on the uphill section.

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