Vehicle control method and vehicle control system

Abstract

An object of the present invention is to provide a vehicle control system that suppresses a decrease in the state of charge (SOC) of a battery and extends the vehicle's driving range even when the engine's output is limited. The control system comprises: an electric motor that drives the vehicle; an engine that drives a generator that generates electricity to obtain power supplied to the electric motor; a battery that is configured to be charged by the generator and is electrically connected to the electric motor; and a controller that controls the electric motor, wherein the controller limits the driving force of the electric motor when the vehicle is traveling in an environment where the engine's output is limited.

Description

Technical Field

[0001] The present invention relates to a control method for a vehicle and a control system for a vehicle, wherein the vehicle comprises:

[0002] an electric motor that drives the vehicle, and an engine that drives a generator that generates electric power to be supplied to the electric motor. Background Art

[0003] Currently, so-called series hybrid vehicles are known. These vehicles include an electric motor that drives the vehicle and an engine that drives a generator that generates electricity to supply the electric motor. In these series hybrid vehicles, the engine is stopped and started depending on the battery's state of charge and the vehicle's required power.

[0004] However, at high altitudes, air density is lower and engine output is reduced, resulting in less power generated by the engine compared to flat land. Therefore, for example, JP2014-133457A discloses an engine operation control device for a hybrid vehicle that increases the engine's set rotational speed by correcting for decreasing atmospheric pressure at the vehicle's current location. Summary of the Invention

[0005] In the above-mentioned conventional technology, the engine's set rotational speed increases as atmospheric pressure decreases, thereby ensuring a certain level of engine power generation even at high altitudes. However, if the motor's output remains high, as when traveling on high-altitude highways, the battery's SOC decreases, potentially shortening the vehicle's range.

[0006] An object of the present invention is to suppress a decrease in the SOC of a battery and extend the running distance of a vehicle even when the output of an engine is limited.

[0007] One embodiment of the present invention is a method for controlling a vehicle comprising: an electric motor that drives the vehicle; an engine that drives a generator that generates power to supply the electric motor; and a battery that is rechargeable by the generator and electrically connected to the electric motor. The method includes a control step of limiting the driving force of the electric motor when the vehicle is traveling in an environment where the engine output is limited. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a block diagram showing a configuration example of a vehicle according to the first embodiment of the present invention.

[0009] Figure 2A This is a diagram showing an example of a normal charge and discharge map.

[0010] Figure 2B This is a diagram showing an example of a charge-discharge map for plateau use.

[0011] Figure 3A This is a graph showing an example of the relationship between the air density correction factor and altitude.

[0012] Figure 3B This is a diagram showing an example of the relationship between engine output and altitude.

[0013] Figure 3C This is a diagram showing an example of the relationship between the upper limit of the drive output of the electric motor and the altitude.

[0014] Figure 3D This is a diagram showing an example of the relationship between the total value of the engine output and the battery output and the altitude.

[0015] Figure 4 This is a diagram showing an example of the relationship between the requested driving force and the vehicle speed.

[0016] Figure 5 This is a flowchart showing an example of a processing procedure of a vehicle control process executed by a vehicle control system.

[0017] Figure 6 This is a diagram showing an example of the relationship between the requested driving force and the vehicle speed according to the second embodiment.

[0018] Figure 7 This is a flowchart showing an example of a processing procedure of a vehicle control process executed by the vehicle control system according to the third embodiment. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0020] [Example of vehicle structure]

[0021] Figure 1 This is a block diagram showing a configuration example of a vehicle 1 according to the first embodiment of the present invention.

[0022] Vehicle 1 includes an engine 11, a generator 12, a battery 13, an electric motor 14, an inverter 15, a drive system controller 100, and a power generation system controller 200. Vehicle 1 also includes a kick-down accelerator switch (not shown) that is activated by depressing the accelerator pedal to a predetermined position. The kick-down accelerator switch is sometimes also referred to as a step-down force pedal.

[0023] The drive system controller 100 and the power generation system controller 200 are control devices for controlling various devices, and are composed of, for example, a microcomputer having a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface).

[0024] The drive system controller 100 functions as a control unit that executes a specific program to control the operations of various devices included in the vehicle 1 , such as the battery 13 , the motor 14 , and the inverter 15 .

[0025] The power generation system controller 200 functions as a control unit that executes a specific program to control the operations of various devices included in the vehicle 1 , such as the engine 11 , the generator 12 , and the battery 13 .

[0026] Furthermore, the drive system controller 100 and the power generation system controller 200 may each be composed of multiple microcomputers rather than a single microcomputer. Alternatively, the drive system controller 100 and the power generation system controller 200 may be composed of a single microcomputer. In this manner, the drive system controller 100 and the power generation system controller 200 constitute the control system of the vehicle 1.

[0027] Vehicle 1 is configured as a so-called series hybrid vehicle. In other words, electric power generated by a generator 12 using the power of an engine 11 is supplied to a battery 13 via an inverter 15. The electric power from the battery 13 rotates an electric motor 14, thereby driving the drive wheels (not shown) of the vehicle 1. Therefore, in the vehicle 1, the engine 11 is not used as a power source for driving the vehicle 1, but rather as a power source for generating electricity for the generator 12.

[0028] The engine 11 is a so-called internal combustion engine that uses gasoline or the like as fuel, and is mechanically connected to the generator 12. The engine 11 is used as a driving source for rotating the generator 12 when the battery 13 is charged or the like.

[0029] The generator 12 is configured to generate electricity based on the power from the engine 11 and can charge the battery 13. Furthermore, the generator 12 is configured to rotate using the power from the battery 13, thereby power-running the engine 11 (electrically). This electric-running control, which rotates the engine 11 using the power of the generator 12, allows the engine 11 to be cranked when starting the engine 11, or to generate negative pressure in the intake passage by closing the throttle valve when negative pressure is required for brake pedal assistance. As described above, the generator 12 functions as both a generator motor and an engine starter.

[0030] The drive system controller 100 includes a target drive force calculation unit 101 , a torque conversion unit 102 , a plateau determination unit 103 , a K / D determination unit 104 , a drive torque limiter 105 , and a selection unit 106 .

[0031] The target driving force calculation unit 101 calculates the driving force required for the vehicle 1 (the torque command value for the electric motor 14) based on the accelerator pedal opening (APO) and the vehicle speed, and outputs the calculation result to the selection unit 106. The driving force is also referred to as driving torque. The accelerator pedal opening can be obtained based on the amount of operation of the accelerator pedal of the vehicle 1, and the vehicle speed can be obtained using the vehicle speed sensor of the vehicle 1.

[0032] The torque conversion unit 102 calculates the driving force that can be supplied from the battery 13 to the electric motor 14 based on the maximum electric power that can be supplied by the battery 13 , and outputs the calculation result to the selection unit 106 .

[0033] The plateau determination unit 103 determines whether the vehicle 1 is traveling in an environment where the output of the engine 11 is limited, and outputs the determination result to the drive torque limiting unit 105. Here, the environment where the output of the engine 11 is limited is, for example, an environment with low air density. That is, the environment where the output of the engine 11 is limited is, for example, an environment where the intake air volume of the engine 11 is reduced. In addition, it can be imagined that the environment where the output of the engine 11 is limited is an environment where the power generation based on the engine 11 cannot be fully ensured. The environment where the output of the engine 11 is limited refers to, for example, a place exceeding a prescribed altitude, that is, a plateau. In addition, the environment where the output of the engine 11 is limited refers to, for example, a place with a prescribed temperature or higher, such as a tropical region. However, in the first embodiment, in order to facilitate the description, the vehicle 1 is shown to have reached an altitude of TH1 (refer to Figures 3A to 3D ) is determined as an example of an environment in which the output of the engine 11 is restricted. In addition, the altitude TH1 can be set to approximately 2800 m, for example.

[0034] Specifically, the plateau determination unit 103 obtains the air pressure from the air pressure sensor that measures the air pressure of the air inhaled by the engine 11, and obtains the temperature from the temperature sensor that measures the temperature of the air inhaled by the engine 11. Furthermore, the plateau determination unit 103 calculates the air density of the place where the vehicle 1 is present based on the obtained air pressure and temperature, and determines whether the vehicle 1 has reached the altitude TH1 based on the air density. Specifically, when the air density is greater than or equal to a specified value, the plateau determination unit 103 determines that it is not a plateau, and when the air density is less than a specified value, it determines that it is a plateau. In addition, in this embodiment, an example of plateau determination using air pressure and temperature is shown, but plateau determination may also be performed using at least one of air pressure and temperature. In addition, regarding the determination example, refer to Figures 3A to 3D Provide detailed explanation.

[0035] The K / D determination unit 104 determines whether the driver has turned on the kick-down switch based on a signal from the kick-down switch, and outputs the determination result to the drive torque limiting unit 105 .

[0036] The driving torque limiting unit 105 sets a limit value for limiting the driving force of the motor 14 based on the determination result output from the plateau determination unit 103 and the determination result output from the K / D determination unit 104, and outputs the limit value to the selection unit 106. Figure 3C 、 Figure 3D 、 Figure 4 Provide detailed explanation.

[0037] The selection unit 106 selects the required driving force for the vehicle 1 (the torque command value for the electric motor 14) based on the driving force output from the target driving force calculation unit 101, the driving force output from the torque conversion unit 102, and the limit value output from the driving torque limiter 105, and outputs the selected result to the inverter 15 and the power conversion unit 201. Specifically, the selection unit 106 selects the minimum value from the values ​​output from the target driving force calculation unit 101, the torque conversion unit 102, and the driving torque limiter 105. Furthermore, the selection unit 106 outputs the selected value to the power conversion unit 201 of the power generation system controller 200, indicating the required driving torque level for the electric motor 14.

[0038] The power generation system controller 200 includes a power conversion unit 201, a plateau determination unit 202, a normal charge and discharge correspondence map storage unit 203, a plateau charge and discharge correspondence map storage unit 204, a correspondence map selection unit 205, an addition unit 206, a gear number storage unit 207, an α-line speed calculation unit 208, a minimum value selection unit 209, a plateau speed calculation unit 210, a speed selection unit 211, and a maximum value selection unit 212.

[0039] Power conversion unit 201 converts the driving force (torque command value of electric motor 14 ) output from selection unit 106 into a power value (output power value of battery 13 ), and outputs the converted power value to addition unit 206 .

[0040] Plateau determination unit 202 determines whether vehicle 1 is traveling in an environment where the engine 11's output is restricted, and outputs its determination result to map selection unit 205 and speed selection unit 211. Its determination method is the same as that of plateau determination unit 103. Alternatively, power generation system controller 200 may omit plateau determination unit 202 and utilize the determination result from plateau determination unit 103.

[0041] The normal time charge and discharge correspondence map storage unit 203 stores the normal time charge and discharge correspondence map used when it is determined that the vehicle 1 is in a place other than a plateau (a normal place), and supplies the stored charge and discharge correspondence map to the correspondence map selection unit 205. Figure 2A Provide detailed explanation.

[0042] The plateau charge-discharge map storage unit 204 stores a plateau charge-discharge map used when it is determined that the vehicle 1 is at a plateau, and supplies the stored charge-discharge map to the map selection unit 205. Figure 2B Provide detailed explanation.

[0043] Map selection unit 205 selects a charge-discharge map for charging and discharging battery 13 based on the determination result of plateau determination unit 202, and supplies the selected charge-discharge map to adder unit 206. Specifically, if plateau determination unit 202 determines that the environment is plateau, map selection unit 205 selects a charge-discharge map for plateau use; if plateau determination unit 202 does not determine that the environment is plateau, map selection unit 205 selects a charge-discharge map for normal operation.

[0044] Adding unit 206 adds the power value output from power conversion unit 201 to the value determined using the charge-discharge map output from map selection unit 205, and outputs the addition result to α-line rotational speed calculating unit 208 and plateau rotational speed calculating unit 210. Specifically, calculations by α-line rotational speed calculating unit 208 and plateau rotational speed calculating unit 210 are performed based on the power value (the output power value of battery 13) corresponding to the torque command value of electric motor 14 and the charge-discharge map corresponding to the plateau determination result.

[0045] The gear number storage unit 207 stores the gear number (rotation speed for each vehicle speed) for which the optimal rotation speed of the engine 11 is set for each vehicle speed in consideration of fuel efficiency and noise generated by the engine 11 , and supplies the stored gear number to the minimum value selection unit 209 .

[0046] α-line speed calculation unit 208 calculates the speed of the α-line based on the added value output from adder unit 206 and outputs the calculation result to minimum value selection unit 209. Here, the α-line represents the speed of engine 11 that achieves the best fuel efficiency for each engine output. That is, the α-line can be used to determine the speed of engine 11 that achieves the best fuel efficiency based on each added value.

[0047] Minimum value selection unit 209 selects the smaller value from the calculation result of α-line rotation speed calculation unit 208 and the gear number stored in gear number storage unit 207, and supplies the selected value to maximum value selection unit 212. In other words, minimum value selection unit 209 selects the smaller value from the rotation speed of α-line obtained based on the added value output from addition unit 206 and the optimal rotation speed corresponding to the speed of vehicle 1.

[0048] The plateau speed calculation unit 210 calculates the speed of the engine 11 for plateau use based on the added value output from the adder unit 206, and outputs the calculated result to the speed selection unit 211. The speed of the engine 11 for plateau use is a value for outputting the torque required for plateau use at a speed as low as possible in consideration of the plateau environment.

[0049] Based on the determination result of plateau determination unit 202, rotation speed selection unit 211 selects one value from the calculation result of plateau rotation speed calculation unit 210 and "0" as the rotation speed of engine 11 driving generator 12, and supplies the selected value to maximum value selection unit 212. Specifically, if the plateau is determined, rotation speed selection unit 211 selects the calculation result of plateau rotation speed calculation unit 210; if the plateau is not determined, it selects "0".

[0050] Maximum value selector 212 selects the larger value from the value selected by minimum value selector 209 and the value selected by rotation speed selector 211, and outputs the selected value to engine 11. That is, the rotation speed of engine 11 is controlled based on the value selected by maximum value selector 212.

[0051] [Charts for normal and plateau charging and discharging]

[0052] Figure 2A This is a diagram showing an example of a normal charge and discharge map. Figure 2B is a diagram showing an example of a charge-discharge correspondence diagram for plateau use. Figure 2A and Figure 2B In the figure, the vertical axis represents the additional charge amount "kW" of the battery 13, and the horizontal axis represents the SOC (States Of Charge) "%". Here, the additional charge amount refers to the amount of electricity that is used to charge the battery 13 from the electricity generated by the generator 12. For example, if the additional charge amount is a positive value, charging occurs, and if the additional charge amount is a negative value, discharging occurs. That is, in the case of discharging, the electric power of the battery 13 is used to drive the motor 14. In addition, Figure 2A and Figure 2B , an example of controlling the lower limit of the additional charge amount of the battery 13 is shown. Figure 2A An example of the lower limit line of the additional charge amount in normal conditions is shown in FIG. Figure 2B An example of the lower limit line of the additional charge amount in the plateau is shown in FIG.

[0053] In addition, the charge and discharge map stores a plurality of maps according to the vehicle speed. Figure 2A and Figure 2B In order to facilitate the explanation, an example of a map is shown when the vehicle speed is V1 (kph (kilometer per hour)). V1 is, for example, the vehicle speed when traveling at a high speed.

[0054] like Figure 1 As shown, the adding unit 206 adds the value of the power conversion unit 201 (the power value corresponding to the torque command value of the motor 14) and Figure 2A or Figure 2B In this case, if it is not determined to be a plateau (normal), use Figure 2A The normal charge and discharge correspondence diagram shown in the figure is used when it is determined to be a plateau. Figure 2B Furthermore, based on the information from the battery 13, the value of the additional charge amount "kW" (vertical axis) corresponding to the current SOC of the battery 13 is added.

[0055] like Figure 2A As shown, when the vehicle is not determined to be on a plateau (normal operation), and the vehicle speed is V1, if the SOC is less than So1, the additional charge amount "kW" is a positive value. Furthermore, when the vehicle speed is V1 during normal operation, if the SOC is greater than or equal to So1, the additional charge amount "kW" is a negative value. Thus, even during normal operation, when the vehicle speed is V1, the minimum SOC of the battery 13 is set to be greater than or equal to So1.

[0056] like Figure 2BAs shown, when the vehicle is determined to be on a plateau and the vehicle speed is V1, the additional charge amount "kW" is a positive value when the SOC is less than So2. Alternatively, when the vehicle is determined to be on a plateau and the vehicle speed is V1, the additional charge amount "kW" is a negative value when the SOC is greater than or equal to So2. Thus, even when the vehicle is determined to be on a plateau and the vehicle speed is V1, the minimum SOC of battery 13 is set to be greater than or equal to So2.

[0057] Here, as Figure 2A and Figure 2B As shown, So1 is smaller than So2. That is, Figure 2A The additional charge capacity shown ( Figure 2A The vertical axis) is 0kW and the SOC is less than Figure 2B The additional charge capacity shown ( Figure 2B In addition, in this embodiment, Figure 2A and Figure 2B The additional charge amount shown is 0kW SOC ( Figure 2A So1 shown, Figure 2B The SOC centers (So1, So2) shown in FIG. 1 and FIG. 2 are referred to as "SOC centers" for the following description. The SOC centers (So1, So2) can be set using various experimental data such as the performance of the battery, the engine, and the generator.

[0058] In addition, in this embodiment, an example is shown in which only the lower limit of the additional charge amount of the battery 13 is controlled, but the upper limit of the additional charge amount of the battery 13 may also be controlled. In addition, in this embodiment, an example is shown in which two stages of control are performed depending on whether the vehicle is determined to be at a high altitude, but three or more stages of control may also be performed depending on the altitude of the vehicle 1.

[0059] [Example of driving force restriction]

[0060] Figures 3A to 3D , an example of limiting the driving force based on the plateau determination threshold TH1 is shown. Figures 3A to 3D In order to facilitate the explanation, each relationship is simplified.

[0061] Figure 3A This is a graph showing an example of the relationship between the air density correction factor and the altitude [m]. In addition, the air density can be calculated based on the air pressure and temperature. In addition, the altitude can be determined based on the air density. Figure 3A In order to facilitate the explanation, the relationship between the air density correction coefficient and the altitude [m] is simplified and shown by a straight line AD1.

[0062] The air density correction factor represents the ratio of the amount of air that can be inhaled by the engine 11, when the vehicle 1 is at an altitude of 0 m and is set to "1." For example, if the engine 11 has a maximum output of 100 kW, an air density correction factor of 1 enables an engine output of 100 kW, while an air density correction factor of 0.9 enables an engine output of 90 kW. Specifically, as the altitude of the vehicle 1 increases, the value of the air density correction factor decreases accordingly, as shown by straight line AD1.

[0063] As described above, the first embodiment illustrates an example where the vehicle 1 is determined to be at a plateau when it reaches altitude TH1, for example, 2800 meters. Specifically, the example illustrates an example where altitude TH1 is used as the plateau determination threshold TH1. Furthermore, the plateau determination threshold TH1 can be set using various experimental data on battery, engine, and generator performance depending on altitude.

[0064] In this way, the plateau determination threshold TH1 can be set for the air density to determine whether the area is plateau, and control related to limiting the driving force of the electric motor 14 and ensuring the SOC of the battery 13 at plateaus can be performed.

[0065] Figure 3B is a graph showing an example of the relationship between engine output [kw] and altitude [m]. Figure 3B In order to facilitate the explanation, the relationship between the engine output [kW] and the altitude [m] is simplified and shown by a straight line EP1.

[0066] As described above, the maximum output of the engine 11 can be multiplied by Figure 3A The engine output corresponding to the altitude is calculated by applying the air density correction factor shown in FIG. That is, as the altitude increases, the engine output decreases accordingly.

[0067] Figure 3C 1 is a diagram showing an example of the relationship between the upper limit [kW] of the drive output of the electric motor 14 and the altitude [m].

[0068] like Figure 3C As shown by line DL1, when the altitude of vehicle 1 is lower than plateau determination threshold TH1, the driving force of motor 14 is not limited. That is, the minimum value of the driving forces calculated by target driving force calculation unit 101 and torque conversion unit 102 is set as the driving force of motor 14.

[0069] like Figure 3CAs shown by line DL3, when the altitude of vehicle 1 exceeds plateau determination threshold TH1, the upper limit of the driving force of electric motor 14 is limited. Furthermore, the amount of limitation gradually increases until the altitude of vehicle 1 exceeds plateau determination threshold TH1 and reaches threshold TH2 (where TH1 < TH2). Furthermore, when the altitude of vehicle 1 exceeds threshold TH2, the amount of limitation remains constant. By limiting the upper limit of the driving force of electric motor 14 in this way, the SOC of battery 13 is prevented from being excessively depleted.

[0070] Here, when the driver steps on the accelerator to accelerate, the downshift accelerator switch is turned on. In this case, if the upper limit of the driving force of the motor 14 is limited, the driver will not be able to get the desired acceleration feeling, which will cause a sense of discomfort to the driver. Therefore, even if the altitude of the vehicle 1 exceeds the plateau determination threshold TH1, when the downshift accelerator switch is turned on, the vehicle 1 will not be accelerated. Figure 3C As shown by the line DL2 , the restriction on the driving force of the electric motor 14 is relaxed.

[0071] In this way, when the downshift-acceleration switch is on, the driving force used for releasing the downshift-acceleration is used for limitation. This allows the driver's acceleration intention to be reflected even at high altitudes. Furthermore, the existing downshift-acceleration switch can be used to determine the driver's acceleration intention and use it to control the limitation of the driving force of the electric motor 14.

[0072] Thus, in the first embodiment, when the altitude of the vehicle 1 exceeds the plateau determination threshold value TH1, the driving force of the electric motor 14 is limited as shown by line DL3. However, when the downshift accelerator switch is turned on, the driving force of the electric motor 14 is limited based on the downshift accelerator switch being turned on (an example of an acceleration operation of the vehicle 1), as shown by line DL2.

[0073] Figure 3D This is a diagram showing an example of the relationship between the total value [kW] of the engine output and the battery output and the altitude [m]. Figure 3D The vertical axis of represents an output that can be used for driving the vehicle 1. That is, an example of a relationship when information related to the outputs of the engine 11 and the battery 13 is viewed from the power axis is shown.

[0074] Figure 3D The straight line EB1 shown represents the Figure 3B The value of the straight line EP1 shown is Figure 3C The value obtained by adding the value of the line DL1 shown in FIG. Figure 3D The line EB2 shown represents the Figure 3B The value of the straight line EP1 shown is Figure 3C The value obtained by adding the value of the line DL2 shown in FIG. Figure 3D The line EB3 shown represents the Figure 3B The value of the straight line EP1 shown is Figure 3C The value of line DL3 shown is added.

[0075] In addition, when the altitude of the vehicle 1 exceeds the plateau determination threshold TH1, Figure 3D The dashed line EB4 shown indicates that no Figure 3C The value in the case of the restriction shown (restriction of the upper limit value of the driving force of the electric motor 14).

[0076] in addition, Figure 3D The dotted line BT1 shows the Figure 3B The straight line EP1 corresponds to the amount of electricity generated by the engine output. Figure 3D As shown by the relationship between dashed line BT1 and line EB3, if the altitude of vehicle 1 exceeds plateau determination threshold TH1 and is near threshold TH2, the value of line EB3 is less than that of dashed line BT1. In other words, by limiting the upper limit of the driving force of electric motor 14, an amount of electric power that can be generated by engine output is not used to drive electric motor 14. In other words, a charge margin is generated. Therefore, when the altitude of vehicle 1 exceeds threshold TH2 and the downshift accelerator switch is not turned on, battery 13 can be charged using electric power generated by engine output, preventing battery 13 from running out of power. Furthermore, battery 13 running out of power means that the SOC of battery 13 is less than a specified value. For example, if the SOC of battery 13 is less than 40%, it is determined that the SOC of battery 13 is depleted.

[0077] In this way, when the altitude of the vehicle 1 exceeds the plateau determination threshold TH1 and exceeds the threshold TH2, the line EB3 is set below the dotted line BT1 so that the battery 13 can be charged, thereby preventing the SOC of the battery 13 from being depleted. However, immediately after the altitude of the vehicle 1 exceeds the plateau determination threshold TH1, if the upper limit of the driving force of the electric motor 14 is limited so that the line EB3 is lower than the dotted line BT1, the sudden change in the driving force may cause a sense of discomfort to the driver. Therefore, until the altitude of the vehicle 1 exceeds the plateau determination threshold TH1 and reaches the threshold TH2, as shown in FIG. Figure 3D As shown by line EB3, the upper limit of the driving force of the motor 14 is gradually limited according to the altitude of the vehicle 1. When the altitude of the vehicle 1 exceeds the threshold TH2, the upper limit of the driving force of the motor 14 is limited so that the line EB3 is lower than the dotted line BT1.

[0078] For example, when traveling on a highway while engine output is reduced at high altitudes, if the power supply from battery 13 to electric motor 14 is continued unrestricted based on the driver's accelerator pedal pressure, battery 13's power could be rapidly depleted. In other words, even though engine output is reduced at high altitudes, if the power output is continued unrestricted, battery 13's SOC could be rapidly depleted. If battery 13 power is depleted, the output of electric motor 14 must be supplemented solely with power generated by engine 11, resulting in a significant need to limit the driving force of electric motor 14, leading to a feeling of insufficient acceleration. Such restrictions on highways, for example, could lead to driver dissatisfaction.

[0079] Therefore, in the first embodiment, the upper limit of the driving force of the electric motor 14 is limited based on the plateau determination threshold TH1. Furthermore, when the altitude of the vehicle 1 exceeds the plateau determination threshold TH1, a charge margin is established based on a value near the threshold TH2. In other words, when the vehicle 1 reaches an altitude between the plateau determination threshold TH1 and the threshold TH2, no charge margin is established. However, when the altitude of the vehicle 1 exceeds the threshold TH2, a charge margin is established. Thus, in the first embodiment, the control of the driving force of the electric motor 14 and the control of the charge margin of the battery 13 are modified based on the plateau determination thresholds TH1 and TH2.

[0080] Thus, in the first embodiment, the SOC center of battery 13 can be increased and varied in plateau conditions. Specifically, a charge-discharge map for plateau conditions is prepared, and when the vehicle is determined to be in plateau conditions, the charge-discharge map is switched to that for plateau conditions. In other words, the target SOC value of battery 13 is switched from the target value for flatland conditions to the target value for plateau conditions.

[0081] Furthermore, since the generated power of the battery 13 can be ensured, when the vehicle is determined to be in plateau conditions, the speed for plateau conditions and the speed of the α-line for plateau conditions are calculated, and the speed required for plateau conditions can be indicated. Thus, in the first embodiment, when the vehicle is determined to be in plateau conditions, the driving force of the electric motor 14 is limited, and the SOC center of the battery 13 is increased, thereby ensuring an SOC that can withstand acceleration attempts in plateau conditions.

[0082] In addition, Figure 3DAs shown by the relationship between dashed line BT1 and line EB2, even when the altitude of vehicle 1 exceeds threshold TH2, the value of line EB2 remains greater than that of dashed line BT1. In other words, while easing the upper limit on the driving force of electric motor 14, in addition to the power generated by engine output, the power of battery 13 may still be required to drive electric motor 14. If this situation persists, battery 13 may become depleted. However, if the downshift accelerator switch is not turned on, the driving force of electric motor 14 is limited. Therefore, if this limitation continues until the driver indicates an intention to accelerate, the driver may feel a sense of insufficient acceleration. Therefore, when the downshift accelerator switch is turned on, the control shown by line EB2 is executed.

[0083] [Example of Limitation of Driving Force According to Vehicle Speed]

[0084] Figure 4 is a diagram showing an example of the relationship between the requested driving force and the vehicle speed. Figure 4 In FIG. 1 , the vertical axis represents the required driving force "N" and the horizontal axis represents the vehicle speed "kph". Here, the vehicle speed is proportional to the rotation speed of the electric motor 14, so it is also possible to Figure 4 The illustrated example of the relationship between the requested driving force and the vehicle speed is to be understood as an example of the relationship between the requested driving force and the rotational speed of the electric motor 14 .

[0085] Line RD1 shows an example of the relationship between the requested driving force and vehicle speed in an environment not determined to be a plateau. In a low speed region R1 where the rotational speed of the electric motor 14 is less than or equal to the first rotational speed NR1, the requested driving force remains approximately constant relative to changes in the rotational speed of the electric motor 14. Therefore, this region R1 can be referred to as a constant motor torque region.

[0086] Furthermore, in a medium speed region R2 where the rotational speed of the motor 14 is between a first rotational speed NR1 and a second rotational speed NR2 (where NR1 < NR2), the output of the motor 14 remains substantially constant despite changes in the rotational speed of the motor 14. Therefore, this region R2 can be referred to as a constant motor output region.

[0087] In region R3 where the rotation speed of the motor 14 exceeds the second rotation speed NR2, the required driving force and the output of the motor 14 decrease rapidly with changes in the rotation speed of the motor 14. That is, the second rotation speed NR2 corresponds to the upper limit rotation speed at which the motor 14 can exhibit practical performance.

[0088] Line RD3 shows an example of the relationship between the requested driving force and the vehicle speed when the altitude of vehicle 1 is plateau determination threshold TH1. Line RD2 shows an example of the relationship between the requested driving force and the vehicle speed when the downshift accelerator switch is on.

[0089] like Figure 4 As shown, the driving force is not restricted until the vehicle speed reaches S6, regardless of whether it is determined to be a plateau. For example, a series hybrid vehicle can create a pleasant acceleration feeling. In addition, it can be expected that in most cases the accelerator pedal is depressed less frequently on highways and more frequently on urban streets. Thus, when traveling at a speed less than S6, such as on urban streets, appropriate acceleration is often required. Therefore, in urban streets where it is assumed to travel at a lower speed, the characteristics of a series hybrid vehicle can be brought into play, and therefore the driving force is set not to be restricted. That is, normal control is performed on urban streets where the vehicle speed is less than the specified speed.

[0090] In addition, if the vehicle speed exceeds S6, the driving force is limited if it is determined to be high. Figure 4 In the figure, S6 is shown as the vehicle speed threshold TH11, and S8 is shown as the vehicle speed threshold TH12. Note that S6 represents the vehicle speed when traveling on urban streets, etc., and S8 is a value several tens of kph higher than S6. Furthermore, S6 and S8 can be set using various experimental data on battery, engine, and generator performance depending on altitude and vehicle speed.

[0091] That is, in the motor torque constant region R1, the driving force is not limited regardless of whether it is determined to be a plateau. In the motor output constant region R2, the driving force is limited if it is determined to be a high value.

[0092] Furthermore, dotted line DD1 represents the limit value of the driving force of electric motor 14 when the SOC of battery 13 is determined to be depleted, when the altitude of vehicle 1 is at plateau determination threshold TH1. Specifically, dotted line DD1 represents the driving force when electric motor 14 is driven solely by electric power generated by engine output, when battery 13 is determined to be depleted and its power cannot be used.

[0093] exist Figure 4 In the example shown, when the altitude of vehicle 1 is at plateau determination threshold TH1, even if the SOC of battery 13 is determined to be depleted, the driving force of electric motor 14 can be ensured up to the value of dashed line DD1. Furthermore, by setting the relationship between the required driving force and vehicle speed of vehicle 1 below dashed line DD1, battery 13 can be charged using power generated by engine output.

[0094] Thus, in the first embodiment, when the altitude of the vehicle 1 is at the plateau determination threshold TH1, the driving force of the electric motor 14 is limited based on the electric power generated by the engine 11 in this environment. In other words, the driving force of the electric motor 14 is limited so that the electric power generated by the engine 11 in this environment is greater than the electric power requested by the electric motor 14.

[0095] As described above, when the altitude of the vehicle 1 is the plateau determination threshold TH1, the relationship between the requested driving force and the vehicle speed of the vehicle 1 is set below the dashed line DD1, so that the battery 13 can be charged, thereby preventing the SOC of the battery 13 from being depleted. However, if the driving force of the electric motor 14 is limited below the dashed line DD1 immediately after the vehicle speed exceeds the vehicle speed threshold TH11, the sudden change in driving force may cause a sense of discomfort to the driver. Therefore, until the vehicle speed exceeds the vehicle speed threshold TH11 and reaches the vehicle speed threshold TH12, as shown in FIG. Figure 4 As shown by line RD3, the driving force of the motor 14 is gradually limited as the vehicle speed increases. When the vehicle speed exceeds the vehicle speed threshold TH12, the driving force of the motor 14 is limited so that line RD3 is below the dotted line DD1.

[0096] However, when the kick-down switch is on, even when the vehicle speed exceeds the vehicle speed threshold TH12 , the limitation on the driving force of the electric motor 14 is relaxed as shown by the line RD2 .

[0097] Thus, in the first embodiment, when the altitude of the vehicle 1 exceeds the plateau determination threshold value TH1, as shown by lines RD2 and RD3, the limit amount of the driving force of the electric motor 14 is set based on the vehicle speed of the vehicle 1. Furthermore, as shown by line RD2, the limit amount of the driving force of the electric motor 14 is set based on the vehicle speed of the vehicle 1 and the acceleration operation of the vehicle 1 (the turning-on operation of the downshift accelerator switch).

[0098] [Operation example of control device]

[0099] Figure 5 1 is a flowchart showing an example of a processing procedure of a vehicle control process executed by the control system of the vehicle 1. The processing procedure is executed based on a program stored in a storage unit (not shown) of the control system of the vehicle 1.

[0100] In step S501, the plateau determination unit 103 and the plateau determination unit 202 perform plateau determination. If it is determined to be a plateau, the process proceeds to step S505. If it is determined not to be a plateau, the process proceeds to step S502.

[0101] In step S502, the power generation system controller 200 sets a target SOC center for normal operation. Specifically, the map selection unit 205 selects a normal-time charge-discharge map stored in the normal-time charge-discharge map storage unit 203 and sets the charge and discharge of the battery 13 based on the normal-time charge-discharge map. The target SOC center for normal operation refers to the SOC center set as the target during normal operation (the SOC at an additional charge of 0 kW).

[0102] In step S503, the power generation system controller 200 sets the normal engine speed. Specifically, the α-line speed calculation unit 208 calculates the speed based on the α-line of the normal charge-discharge map. The speed selection unit 211 selects "0." Furthermore, the maximum value selection unit 212 selects the value selected by the minimum value selection unit 209 (the smaller of the speed based on the α-line of the normal charge-discharge map and the optimal speed corresponding to the vehicle 1 speed) as the engine speed.

[0103] In step S504, the drive system controller 100 outputs an instruction to the inverter 15 for controlling the drive force of the vehicle 1 based on the value selected by the selection unit 106. Since the vehicle is not at a plateau, the selection unit 106 selects the minimum value of the drive forces calculated by the target drive force calculation unit 101 and the torque conversion unit 102.

[0104] In step S505, the power generation system controller 200 sets a target SOC center for high altitude conditions. Specifically, the map selection unit 205 selects a high altitude charge-discharge map stored in the high altitude charge-discharge map storage unit 204 and sets the charge and discharge of the battery 13 based on the high altitude charge-discharge map. The target SOC center for high altitude conditions refers to the SOC center set as the target when the high altitude condition is determined (the SOC at which the additional charge amount is 0 kW). Thus, in the first embodiment, when the high altitude condition is determined, the target SOC center for the battery 13 is set to a higher value than before the high altitude condition was determined.

[0105] In step S506, the power generation system controller 200 sets the engine speed for high altitude use. Specifically, the α-line speed calculation unit 208 calculates the speed based on the α-line of the high altitude charge-discharge map. Furthermore, the minimum value selection unit 209 selects the smaller of the speed based on the α-line of the high altitude charge-discharge map and the optimal speed corresponding to the speed of vehicle 1. Furthermore, the speed selection unit 211 selects the speed of the engine 11 for high altitude use, calculated by the high altitude speed calculation unit 210. Furthermore, the maximum value selection unit 212 selects the larger of the value selected by the minimum value selection unit 209 and the value selected by the speed selection unit 211 (the speed of the engine 11 for high altitude use) as the engine speed.

[0106] In step S507, the K / D determination unit 104 performs a K / D determination to determine whether the downshift accelerator switch is on. If the downshift accelerator switch is on, the process proceeds to step S509, and if the downshift accelerator switch is not on, the process proceeds to step S508.

[0107] In step S508, the driving torque limiting unit 105 sets a limit value of the driving force for plateau use. Figure 3C Line DL3, Figure 4 The limit value of the driving force for plateau is set as shown in line RD3.

[0108] In step S509, the driving torque limiting unit 105 sets the driving force limitation for plateau use to be released at a predetermined value. Figure 3C Line DL2, Figure 4 The limit value of the driving force for plateau use when the downshift accelerator switch is on is set as shown in line RD2.

[0109] In step S510, the selection unit 106 performs a vehicle speed determination to determine whether the vehicle speed is greater than or equal to a prescribed value. Furthermore, when the vehicle speed is greater than or equal to the prescribed value, the selection unit 106 selects the limit value of the driving force for plateau use set by the driving torque limiter 105 in step S508 or S509, and proceeds to step S508. However, when the value set by the driving torque limiter 105 is greater than the value calculated by the target driving force calculation unit 101 or the torque conversion unit 102, the minimum value of the driving force calculated by the target driving force calculation unit 101 and the torque conversion unit 102 is selected. On the other hand, when the vehicle speed is less than the prescribed value, the selection unit 106 selects the minimum value of the driving force calculated by the target driving force calculation unit 101 and the torque conversion unit 102, and proceeds to step S504.

[0110] That is, when the vehicle speed is less than a specified value, for example Figure 4 In the case of S6 (kph) shown, the driving force is not limited even when it is determined to be in a plateau. However, regardless of whether the vehicle speed is less than the specified value, if it is determined to be in a plateau, the target SOC center for the plateau is set and the engine speed is set for the plateau.

[0111] In step S511 , the drive system controller 100 outputs an instruction for controlling the drive force of the vehicle 1 to the inverter 15 based on the value selected by the selection unit 106 .

[0112] Here, a technology is envisioned that limits the vehicle's driving force after the battery's SOC decreases. This technology increases the battery's SOC after it decreases, using electricity generated by the engine. In this way, a portion of the electricity generated by the engine is used to increase the battery's SOC, limiting the amount of electricity used as driving force when driving the electric motor. In other words, to increase the battery's SOC, the vehicle's driving force is further limited. If the vehicle's driving force is significantly limited in this way, the vehicle's driving force will differ significantly before and after the battery's SOC decreases, potentially causing driver dissatisfaction.

[0113] In contrast, in the first embodiment, when it is determined that the vehicle is on a plateau, control is performed to limit the driving force of the vehicle 1 even when the SOC of the battery 13 is not reduced. That is, when it is determined that the vehicle is on a plateau, control is performed to limit the driving force of the vehicle 1 regardless of the SOC of the battery 13. As a result, the distance that can be traveled at high output can be extended. That is, the driving force of the vehicle 1 is limited even when the SOC of the battery 13 is large, so the reduction in the SOC of the battery 13 can be made smoother than the above-mentioned technology. As a result, the time until a lower SOC state that significantly limits the driving force of the vehicle 1 can be extended, and the distance (time) that can be traveled at high output can be extended.

[0114] Furthermore, in the first embodiment, when the vehicle is determined to be in a high altitude and there is no intention to accelerate (i.e., when the downshift accelerator switch is not on), the driving force of the electric motor 14 is limited. On the other hand, when the vehicle is determined to be in a high altitude and there is an intention to accelerate (i.e., when the downshift accelerator switch is on), the limitation on the driving force of the electric motor 14 is relaxed. This can extend the time required to reach a lower SOC state that responds to the driver's intention to accelerate and significantly limits the driving force of the vehicle 1, thereby increasing the distance (time) that can be traveled at high output.

[0115] Thus, according to the first embodiment, when the vehicle 1 is located on a plateau, the driving force of the electric motor 14 can be limited as the engine output decreases. In addition, the SOC of the battery 13 can be moderated by limiting the driving force of the electric motor 14. In addition, the SOC center of the battery 13 can be increased and changed by switching to a charge and discharge map for plateaus and calculating the engine speed for plateaus. In addition, the presence or absence of the driver's intention to accelerate is determined, and when the driver's intention to accelerate is present, the restriction on the driving force of the electric motor 14 can be relaxed. Thus, when the vehicle 1 is located on a plateau, the reduction in the SOC of the battery 13 can be suppressed, and control can be performed so that the minimum vehicle speed is maintained for a long time when the accelerator pedal is depressed.

[0116] As described above, according to the first embodiment, even in an environment where the output of the engine 11 is limited, a decrease in the SOC of the battery 13 can be suppressed, thereby extending the running distance of the vehicle 1 .

[0117] [Effects of the First Embodiment]

[0118] The vehicle control method according to the first embodiment is a method for controlling a vehicle 1 including: an electric motor 14 that drives the vehicle 1; an engine 11 that drives a generator 12 that generates electric power to supply the electric motor 14; and a battery 13 that is rechargeable by the generator 12 and electrically connected to the electric motor 14. The control method includes a control step (steps S505 to S511) of limiting the driving force of the electric motor 14 when the vehicle is traveling under an environment in which the output of the engine 11 is limited.

[0119] According to this vehicle control method, the driving force of the electric motor 14 is limited in response to the reduction in engine output at high altitudes, thereby suppressing a decrease in the SOC of the battery 13 and extending the running distance of the vehicle 1 .

[0120] Furthermore, in the vehicle control method according to the first embodiment, in the control step (steps S510 and S511 ), when the vehicle 1 is traveling in an environment where the output of the engine 11 is limited, the limit amount of the driving force of the electric motor 14 is set based on the vehicle speed of the vehicle 1 .

[0121] According to this vehicle control method, the driving force of the electric motor 14 can be adjusted based on the vehicle speed of the vehicle 1 , thereby providing a comfortable operating environment for the driver.

[0122] In the vehicle control method according to the first embodiment, in the control step (steps S510 and S511), when the vehicle 1 is traveling in an environment where the output of the engine 11 is limited, the vehicle 1 is controlled at a predetermined value (e.g., Figure 4 The driving force of the motor 14 is limited when the vehicle speed is high based on S6 (kph) shown, and is not limited when the vehicle speed is low based on a predetermined value.

[0123] According to this vehicle control method, the driving force of the motor 14 is not limited in areas where the vehicle is expected to travel at low speeds, such as urban streets, and is limited in areas where the vehicle is expected to travel at high speeds, such as highways. In this way, the driving force of the motor 14 can be adjusted based on the vehicle speed.

[0124] In addition, in the control method of the vehicle involved in the first embodiment, in the control steps (steps S507, S509), when the vehicle 1 is traveling in an environment where the output of the engine 11 is limited and the vehicle speed of the vehicle 1 is high based on a prescribed value, when the downshift acceleration switch is turned on (an example of a prescribed acceleration operation), the restriction on the driving force of the electric motor 14 is relaxed.

[0125] According to this vehicle control method, it is possible to determine whether the driver has an intention to accelerate, and adjust the driving force of the electric motor 14 based on the driver's intention to accelerate and the vehicle speed.

[0126] In addition, in the vehicle control method involved in the first embodiment, in the control step (steps S507, S509), when the vehicle 1 is traveling in an environment where the output of the engine 11 is limited, the limit amount of the driving force of the electric motor 14 is set based on the turning-on operation of the downshift acceleration switch of the vehicle 1 (an example of a prescribed acceleration operation).

[0127] According to this vehicle control method, it is possible to determine whether the driver has an intention to accelerate and adjust the driving force of the electric motor 14 .

[0128] In addition, in the vehicle control method involved in the first embodiment, in the control step (steps S507 to S511), when the vehicle 1 is traveling in an environment where the output of the engine 11 is limited, the limit amount of the driving force of the electric motor 14 is set based on the vehicle speed of the vehicle 1 and the acceleration operation of the vehicle 1.

[0129] According to this vehicle control method, it is possible to determine whether the driver has an intention to accelerate, and adjust the driving force of the electric motor 14 based on the driver's intention to accelerate and the vehicle speed.

[0130] Furthermore, in the vehicle control method according to the first embodiment, in the control step (step S505), when the vehicle 1 is traveling in an environment where the output of the engine 11 is limited, the SOC of the battery 13 at which the additional charge amount is 0 kW can be set to a larger value than before the vehicle 1 is traveling in this environment. That is, the target SOC center of the battery 13 is set higher than before the vehicle 1 is traveling in this environment. In addition, the SOC of the battery 13 at which the additional charge amount is 0 kW is Figure 2A So1 shown, Figure 2B So2 shown, also known as the SOC center.

[0131] According to this vehicle control method, in order to suppress SOC depletion of the battery 13 at plateaus, the driving force of the electric motor 14 is limited according to the reduction in engine output at plateaus, while the SOC center of the battery 13 is controlled to be high.

[0132] Furthermore, in the vehicle control method according to the first embodiment, in the control step (step S508 ), when the vehicle 1 is traveling in an environment where the output of the engine 11 is limited, the driving force of the electric motor 14 is limited based on the power generated by the engine 11 in this environment.

[0133] According to this vehicle control method, the power generation of the engine 11 is reduced at plateaus, so the output value of the motor 14 is set based on the maximum output value of the engine 11 at plateaus, thereby suppressing the reduction of the SOC of the battery 13 and extending the driving distance of the vehicle 1.

[0134] In the vehicle control method according to the first embodiment, in the control step (step S508 ), the driving force of the motor 14 is limited so that the power generated by the engine 11 under the environment where the output of the engine 11 is limited is greater than the power requested by the motor 14 .

[0135] According to this vehicle control method, the power generation of the engine 11 decreases at plateaus, so the output value of the motor 14 is set to be lower than the maximum output value of the engine 11 at plateaus, thereby suppressing the reduction in the SOC of the battery 13 and extending the driving distance of the vehicle 1.

[0136] Furthermore, in the vehicle control method according to the first embodiment, in the control step (steps S510 and S511 ), when the vehicle 1 is traveling in an environment where the output of the engine 11 is limited, the driving force is limited in the constant output range of the electric motor 14 .

[0137] According to this vehicle control method, the driving force of the electric motor 14 is adjusted in the constant output range, thereby providing a comfortable operating environment for the driver.

[0138] The control system of the vehicle 1 according to the first embodiment includes: an electric motor 14 that drives the vehicle 1; an engine 11 that drives a generator 12 that generates electricity to supply the electric motor 14; a battery 13 that is rechargeable by the generator 12 and electrically connected to the electric motor 14; and a drive system controller 100 (an example of a controller) that controls the electric motor 14. The drive system controller 100 limits the driving force of the electric motor 14 when the vehicle 1 is traveling in an environment where the output of the engine 11 is limited.

[0139] According to this control system of the vehicle 1 , the driving force of the electric motor 14 is limited in response to the reduction in engine output at high altitudes, thereby suppressing a decrease in the SOC of the battery 13 and extending the running distance of the vehicle 1 .

[0140] [Second embodiment]

[0141] In the first embodiment, an example is shown in which the upper limit of the driving force of the electric motor is limited when the altitude of the vehicle exceeds the plateau determination threshold TH1. That is, an example of control is shown in which the vehicle is determined to be at a plateau in one stage. However, multiple plateau determination thresholds can be set in advance, and restrictions corresponding to each plateau determination threshold can be executed at the timing when the altitude of the vehicle exceeds these plateau determination thresholds. Therefore, in the second embodiment, an example is shown in which the upper limit of the driving force of the electric motor is limited by setting multiple plateau determination thresholds. In addition, the second embodiment is an example in which a portion of the first embodiment is modified, and parts common to the first embodiment are omitted from the illustration and description.

[0142] [Example of Limitation of Driving Force According to Vehicle Speed]

[0143] Figure 6 : is a diagram showing an example of the relationship between the requested driving force and the vehicle speed in the second embodiment. Figure 6 Yes Figure 4 For example, a part of the deformation Figure 4 The same reference numerals are used for the common parts, and part of the description thereof will be omitted.

[0144] In the second embodiment, an example is shown in which two plateau determination thresholds are set, namely, the plateau determination threshold TH1 (for example, approximately 2800 m) and the plateau determination threshold TH3 (for example, approximately 2300 m).

[0145] Line RD5 shows an example of the relationship between the requested driving force and the vehicle speed when the altitude of vehicle 1 is plateau threshold TH3. Line RD4 shows an example of the relationship between the requested driving force and the vehicle speed when the downshift accelerator switch is on and the altitude of vehicle 1 is plateau threshold TH3.

[0146] like Figure 6 As shown, when the altitude of vehicle 1 is plateau determination threshold TH3, the driving force of electric motor 14 is limited when the vehicle speed exceeds vehicle speed threshold TH11. However, the limit value when the altitude of vehicle 1 is plateau determination threshold TH3 is set to a smaller value than the limit value when the altitude of vehicle 1 is plateau determination threshold TH1.

[0147] Furthermore, in the second embodiment, an example is shown in which two plateau determination thresholds TH1 and TH3 are set to limit the upper limit of the motor driving force. However, three or more plateau determination thresholds may be set to limit the upper limit of the motor driving force.

[0148] As described above, according to the second embodiment, the driving force of the electric motor can be limited in accordance with the degree of altitude at high altitudes.

[0149] [Third embodiment]

[0150] In the first and second embodiments, a vehicle 1 equipped with a kickdown accelerator switch is used as an example. The first and second embodiments are also applicable to vehicles not equipped with a kickdown accelerator switch. Therefore, in the third embodiment, a vehicle not equipped with a kickdown accelerator switch is used as an example. Furthermore, the third embodiment is a partial modification of the first and second embodiments. The illustrations and descriptions of portions common to the first and second embodiments are partially omitted.

[0151] The vehicle of the third embodiment omits Figure 1 In the third embodiment, when the driving force of the electric motor 14 is limited, the restriction is not relaxed in consideration of the downshift accelerator switch. Specifically, the K / D determination unit 104 is not selected. Figure 3C The line DL2 shown, Figure 3D EB2 shown, Figure 4 The line RD2 shown, Figure 6 Therefore, it is possible to further suppress the reduction in the SOC of the battery 13 and further extend the running distance of the vehicle 1.

[0152] [Operation example of control device]

[0153] Figure 7 This is a flowchart showing an example of a processing procedure of a vehicle control process executed by a vehicle control system according to the third embodiment. Figure 7 The example shown is for Figure 5 Part of it is deformed, Figure 5 The same reference numerals are given to the common parts and part of the description is omitted. Figure 7 In, omitted Figure 5 The difference is in steps S507 and S509 shown.

[0154] As described above, according to the third embodiment, in an environment where the output of the engine 11 is limited for a vehicle not equipped with a kick-down switch, a decrease in the SOC of the battery 13 can be further suppressed, thereby further extending the running distance of the vehicle 1 .

[0155] The embodiments of the present invention have been described above. However, the above embodiments merely illustrate a part of application examples of the present invention, and the technical scope of the present invention is not intended to be limited to the specific configurations of the above embodiments.

Claims

1. A method for controlling a vehicle comprising: an electric motor that drives the vehicle; an engine that drives a generator that generates electricity to supply the electric motor; and a battery that is chargeable by the generator and electrically connected to the electric motor, wherein: The vehicle control method comprises: a control step of limiting the driving force of the electric motor when the vehicle is traveling in an environment where the output of the engine is limited; In the control step, when the vehicle is traveling under the environment, the driving force of the motor is limited when the vehicle speed is greater than or equal to a specified value, and the limit amount of the driving force of the motor is set based on the vehicle speed, and the driving force of the motor is not limited when the vehicle speed is less than the specified value.

2. The vehicle control method according to claim 1, wherein: In the control step, when the vehicle is traveling under the environment and the vehicle speed is high based on the predetermined value, the restriction on the driving force of the electric motor is relaxed when a predetermined acceleration operation is performed.

3. The vehicle control method according to claim 1 or 2, wherein: In the control step, when the vehicle is traveling in the environment, the SOC of the battery at which the additional charge amount is 0 kW is set to a larger value than that before the vehicle is traveling in the environment.

4. The vehicle control method according to claim 1 or 2, wherein: In the control step, when the vehicle is traveling under the environment, the driving force of the electric motor is limited based on the electric power generated by the engine under the environment.

5. The vehicle control method according to claim 4, wherein: In the control step, the driving force of the electric motor is limited so that the electric power generated by the engine under the environment is greater than the electric power requested by the electric motor.

6. The vehicle control method according to claim 1 or 2, wherein: In the control step, when the vehicle is traveling under the environment, the driving force is limited in a constant output region of the electric motor.

7. A vehicle control system comprising: an electric motor that drives the vehicle; an engine that drives a generator that generates electricity to supply the electric motor; a battery that is rechargeable by the generator and electrically connected to the electric motor; and a controller that controls the electric motor, wherein: When the vehicle is traveling under an environment in which the output of the engine is limited, the controller limits the driving force of the electric motor. When the vehicle is traveling in the environment, the controller limits the driving force of the motor when the vehicle speed is greater than or equal to a specified value, and sets a limit amount of the driving force of the motor based on the vehicle speed. When the vehicle speed is less than the specified value, the controller does not limit the driving force of the motor.

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