Operation mode control device

Abstract

To enable an improvement in efficiency of a motor system in an electric automobile that includes multiple motors.SOLUTION: A driving mode control apparatus 10 is a device that determines a driving mode for driving on a travel route from multiple driving modes for which the number of systems of motors to be driven is defined, and includes: a travel drive power information acquisition part for acquiring time-series travel drive power in traveling on a travel route; a vehicular speed information obtainment part for obtaining a time-series vehicular speed in the traveling on the travel route; a motor operation estimation part for estimating time-series torque and rotation speed of the motor on the basis of the time-series travel drive power and vehicular speed; an efficiency calculation part for obtaining a time-series efficiency value for each driving mode on the basis of the time-series torque and rotation speed and calculating a total efficiency value on the basis of the time-series efficiency value; a driving mode determination part for determining, as a default driving mode, a driving mode with the highest total efficiency value; and a driving control part for controlling driving by the default driving mode.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a drive mode control device that determines a drive mode for traveling a travel route from a plurality of drive modes, each of which defines the number of systems of motors to be driven, in an electric vehicle equipped with a plurality of motors. [Background technology]

[0002] There is an electric vehicle equipped with a battery and multiple motors that are operated by the output power of the battery. For vehicles driven by multiple motors, a control device is known that controls the distribution of driving force in consideration of the thermal load of the motors and the stability of the vehicle (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-103325 A Summary of the Invention [Problem to be solved by the invention]

[0004] The operating efficiency of a motor varies depending on the torque and rotation speed generated. For example, in an example of a general motor, if a combination of torque and rotation speed is taken as one operating point, the efficient operating point may tend to exist in a region where the torque is medium to high and the rotation speed is medium. In an electric vehicle equipped with a motor system including motors of multiple systems (e.g., two systems), when a large driving force is required for traveling, multiple motors (e.g., two of the two systems) may be operated. However, when the operation of the motors of the two systems causes each motor to operate at a low rotation speed and low load, the efficiency of the motor system may decrease.

[0005] Therefore, an object of the present invention is to provide an operation mode control device that improves the efficiency of the motor system in an electric vehicle equipped with multiple motors, thereby enabling improvements in fuel efficiency, electricity consumption, and cruising range. [Means for solving the problem]

[0006] The driving mode control device according to the present invention is a driving mode control device for determining a driving mode for driving a predetermined driving route from a plurality of driving modes each of which specifies the number of systems of the motor to be driven in an electric vehicle equipped with a battery and a plurality of motor systems, and includes a driving drive force information acquisition unit that acquires driving drive force information indicating a time series of driving drive force required for driving the driving route, a vehicle speed information acquisition unit that acquires information on a time series of vehicle speed planned for driving the driving route as vehicle speed information, and a time series of torque and torque required for the motor for driving the driving route based on the driving drive force information and the vehicle speed information. the motor operation estimation unit estimating the motor torque and rotation speed and the motor efficiency value, and obtaining a time series efficiency value for when the driving route is driven in each driving mode based on the motor operation estimation information, which is information on the estimated time series torque and rotation speed of the motor, and calculating a total efficiency value for each driving mode based on the obtained time series efficiency value; a driving mode determination unit determining the driving mode with the highest efficiency indicated by the total efficiency value as the default driving mode; and a driving control unit controlling the electric vehicle in the default driving mode.

[0007] In this driving mode control device, a time series of motor torque and rotation speed are estimated based on information on a time series of driving force required for traveling the traveling route and a planned time series of vehicle speed. A time series efficiency value for each driving mode is obtained based on the estimated motor torque and rotation speed, and a total efficiency value for each driving mode is calculated based on the time series efficiency value. Then, the driving mode with the highest total efficiency value is determined as the default driving mode. Therefore, it is possible to travel the traveling route in a driving mode with a higher efficiency in motor operation.

[0008] In the drive mode control device, the driving force information acquisition unit may calculate the driving force based on a time-series running resistance calculated using at least the vehicle weight of the electric vehicle and a gradient of the traveling route.

[0009] According to this operation mode control device, the running resistance is calculated based on the vehicle weight of the electric vehicle and the gradient of the travel route, so that information on the running drive force suitable for estimating the motor torque can be obtained.

[0010] In addition, in the driving mode control device, the vehicle speed information acquisition unit may acquire the legal speed associated with the driving route as vehicle speed information, or acquire vehicle speed information by referring to driving history information in which information on the vehicle speeds of vehicles that have traveled the driving route is accumulated, or acquire the vehicle speed of the vehicle traveling on the driving route as vehicle speed information calculated based on at least one of information indicating the current traffic volume on the driving route and information indicating the current time required for the vehicle to travel on the driving route.

[0011] This driving mode control device can obtain information indicating the legal speed of the driving route, the history of the vehicle speed of the vehicle that has traveled the driving route, or the current status of the vehicle traveling on the driving route, thereby obtaining vehicle speed information suitable for estimating the motor rotation speed.

[0012] The driving mode control device may further include a specific event detection unit that detects a predetermined specific event while driving on the driving route, and when a specific event is detected, the efficiency calculation unit calculates a specific section total efficiency value, which is a time-series efficiency value in the specific event section corresponding to the specific event, for each driving mode, and the driving mode determination unit determines the driving mode with the highest specific section total efficiency value as the specific event section driving mode for driving through the specific event section, and the driving control unit may control the electric vehicle in the specific event section driving mode when driving through the specific event section.

[0013] According to this operation mode control device, when a preset specific event is detected, the operation mode with the highest total efficiency value in traveling through the specific event section is determined as the specific event section operation mode, so that it is possible to travel through the specific event space in an operation mode with a higher efficiency in the operation of the motor.

[0014] In addition, in the driving mode control device, the electric vehicle has a lift axle mechanism that can perform levitation control to prevent the wheels of one of the first and second axles from touching the ground, and ground control to cause the wheels of the other axle to touch the ground, the number of motor systems is two, and the driving modes include a first driving mode in which the wheels are driven by one motor system and a second driving mode in which the wheels are driven by two motor systems, and the driving mode control device may further include a drive axle control unit that controls the first and second axles to either levitation control or ground control, and an axle state control unit that performs levitation control on either the first and second axles when the electric vehicle is controlled by the driving control unit in the first driving mode.

[0015] According to this operation mode control device, when the vehicle is controlled in the first operation mode in which the vehicle is driven by a single motor, one of the first axle and the second axle is controlled to be lifted, thereby reducing the running resistance and improving fuel efficiency.

[0016] In addition, in the operation mode control device, the axle state control unit stores at least one of the number of times and the time for which levitation control and ground contact control have been performed for each of the first and second axles as control history information, and when the electric vehicle is controlled in the first operation mode by the operation control unit, the axle for which levitation control is to be performed from the first and second axles may be selected so as to reduce the bias in the number of times or the time for which ground contact control has been performed.

[0017] According to this operation mode control device, when one of the first and second axles is subjected to levitation control, the axle to be subjected to levitation control is selected so that the bias in the number of times or duration of ground contact control is reduced, thereby preventing bias in the lifespan of the unit consisting of each axle due to tire wear during ground contact control, etc.

[0018] In addition, in the driving mode control device, the axle state control unit may acquire load information indicating the load on each of the first axle and the second axle, and when the electric vehicle is controlled in the first driving mode by the driving control unit, the axle of the first axle or the second axle having a smaller load indicated in the load information may be selected as the axle to be subjected to levitation control.

[0019] According to this operation mode control device, the axle with the smaller load out of the first and second axles is subjected to lift control, which makes it possible to shift the load that was distributed to both axles to one of the axles, thereby improving the traction of the axle that is subjected to ground contact control. Effect of the Invention

[0020] According to the present invention, it is possible to provide a driving mode control device that can improve the efficiency of the motor system in an electric vehicle equipped with multiple motors, thereby improving fuel efficiency, electricity consumption, and cruising range. [Brief description of the drawings]

[0021] [Figure 1] 1 is a schematic diagram showing a configuration of an electric vehicle equipped with an operation mode control device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a functional block diagram showing a functional configuration of an operation mode control device. [Diagram 3] 4 is a flowchart showing the process of an operation mode control process in the operation mode control device. [Figure 4]Fig. 4(a) is a diagram showing an example of vehicle speed information indicating a time series of a vehicle speed expected for traveling a travel route, and Fig. 4(b) is a diagram showing an example of traveling driving force information indicating a time series of a traveling driving force required for traveling a travel route. [Diagram 5] 10 is a diagram showing an example of motor efficiency information that associates an operating point of a motor, which is formed by the torque and rotation speed of the motor, with an efficiency value of the motor. FIG. [Figure 6] 11 is a diagram showing an example of specific event detection time control information that associates a specific event with an operation mode control when the specific event is detected. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding elements are designated by the same reference numerals, and duplicated description will be omitted.

[0023] Fig. 1 is a schematic diagram showing the configuration of an electric vehicle equipped with a drive mode control device according to an embodiment. As shown in Fig. 1, a drive mode control device 10 is installed in an electric vehicle V. The electric vehicle V includes a battery 1 and a motor system 3.

[0024] Although the electric vehicle V in this embodiment does not have a generator that supplies power to the battery 1, etc., it may have a generator. That is, the electric vehicle V may be an EV (Electric Vehicle) that does not have a generator, or an FCV (Fuel Cell Vehicle) or a PHV (Plug-in Hybrid Vehicle) that has a generator. When the electric vehicle V has a generator, the generator may be a fuel cell or an engine.

[0025] The battery 1 stores power for driving the motor. The battery 1 may store power supplied from an external source. If the electric vehicle V has a generator, the battery 1 may store power generated by the generator. The battery 1 can also store power generated by a regenerative brake or the like provided on the electric vehicle V.

[0026] The motor system 3 is operated by the output power of the battery 1. The motor system 3 drives wheels 6 provided on the electric vehicle V, thereby causing the electric vehicle V to run.

[0027] The motor system 3 of this embodiment includes two motor systems consisting of a first motor 3A and a second motor 3B. The electric vehicle V may be driven by either one of the first motor 3A and the second motor 3B, or may be driven by two motor systems consisting of the first motor 3A and the second motor 3B.

[0028] The driving mode control device 10 is a device that determines a driving mode for driving a predetermined travel route from a plurality of driving modes each of which specifies the number of motor systems to be driven. In this embodiment, the motor system 3 includes two motor systems consisting of a first motor 3A and a second motor 3B, so the driving mode control device 10 selects and controls one of a first driving mode in which the motor system is driven by one motor system and a second driving mode in which the motor system is driven by two motor systems. Note that, although the electric vehicle V of this embodiment is provided with two motor systems, the number of motor systems is not limited to two. That is, the driving mode control device 10 may select and control the number of motor systems used for driving among three or more motor systems.

[0029] The electric vehicle V may further include a vehicle weight sensor 7. The vehicle weight sensor 7 is provided on each axle and detects the axle weight of each axle. The driving mode control device 10 can obtain information on the vehicle weight from the vehicle weight sensor 7. In addition, the driving mode control device 10 can obtain information on the axle weight for each axle from the vehicle weight sensor 7.

[0030] 2 is a functional block diagram showing a functional configuration of the driving mode control device 10. The driving mode control device 10 includes an ECU (Electronic Control Unit) 100. The ECU 100 is an electronic control unit having a CPU, a ROM, a RAM, and the like. For example, the ECU 100 loads a program recorded in the ROM into the RAM and executes the program loaded into the RAM by the CPU, thereby implementing various functions. The ECU 100 may be composed of multiple electronic units.

[0031] As shown in FIG. 2, the driving mode control device 10 functionally includes a driving route information acquisition unit 11, a vehicle speed information acquisition unit 12, a driving force information acquisition unit 13, a motor operation estimation unit 14, an efficiency calculation unit 15, a driving mode determination unit 16, a driving control unit 17, a specific event detection unit 18, and an axle state control unit 19.

[0032] 3 is a flowchart showing the operation mode control process in the operation mode control device 10. The operation mode control process will be described with reference to FIGS.

[0033] In step S1, the travel route information acquisition unit 11 acquires travel route information, which is various information related to a planned travel route. The travel route information acquisition unit 11 acquires the travel route information from an external server that stores the travel route information in advance or a storage device provided in the driving mode control device 10. The travel route information includes gradient information that indicates the gradient of the travel route in addition to information indicating the position of the travel route. The gradient information is used to acquire the travel resistance as described later. The travel route information including the gradient information and the like may be generated based on the travel history (travel resistance during travel) of a vehicle that has traveled the travel route.

[0034] In step S2, the vehicle speed information acquisition unit 12 acquires information on a time series of vehicle speeds expected during travel along the travel route as vehicle speed information from an external server or a storage device provided in the driving mode control device 10. The vehicle speed information is used to estimate the rotation speeds of the motors 3A and 3B. FIG. 4(a) is a diagram showing an example of vehicle speed information indicating a time series of vehicle speeds expected during travel along the travel route. The vehicle speed information acquisition unit 12 acquires time series vehicle speed information with a predetermined time resolution (for example, 1 sec) as shown in FIG. 4(a).

[0035] Specifically, the vehicle speed information acquisition unit 12 may acquire, as the vehicle speed information, the legal speed associated with each section of the travel route. Also, the vehicle speed information acquisition unit 12 may acquire the vehicle speed information by referring to travel history information in which information on the vehicle speed of the vehicle that traveled the travel route is accumulated. Also, the vehicle speed information acquisition unit 12 may acquire, as the vehicle speed information, the vehicle speed of the vehicle traveling the travel route, calculated based on at least one of information indicating the current state of the traffic volume on the travel route and information indicating the current state of the required time for the vehicle traveling the travel route. The information indicating the current state of the vehicle traveling the travel route may be acquired, for example, via VICS (registered trademark).

[0036] In step S3, the driving force information acquisition unit 13 acquires driving force information indicating a time series of driving force required for traveling the traveling route. Fig. 4(b) is a diagram showing an example of driving force information indicating a time series of driving force required for traveling the traveling route. The driving force information acquisition unit 13 acquires information on the driving force in a time series with a predetermined time resolution (for example, 1 sec) as shown in Fig. 4(b).

[0037] Specifically, the driving force information acquisition unit 13 may acquire the driving force information from a storage device that prestores data on the time series of driving force required for the electric vehicle V to travel the travel route.

[0038] The driving force information acquisition unit 13 may calculate the driving force based on the time-series running resistance. The driving force information acquisition unit 13 may calculate the running resistance using at least the vehicle weight of the electric vehicle V acquired from the vehicle weight sensor 7 and the gradient of the running route. The electric vehicle V can run at a constant speed when the running force it generates is in balance with the running resistance. Therefore, the driving force information acquisition unit 13 may calculate the required driving force in time series based on the time-series running resistance based on the vehicle speed information, vehicle weight, rolling resistance, air resistance, and the gradient of the running route of the electric vehicle V. When the vehicle speed is accelerated, the driving force information acquisition unit 13 calculates the driving force by further taking into account the acceleration resistance. When the vehicle speed is decelerated, the driving force information acquisition unit 13 calculates the surplus of the running resistance as a braking force or a regenerative torque and a regenerative energy. The driving force information acquisition unit 13 may calculate the running resistance and the running force by a known method.

[0039] In step S4, the motor operation estimator 14 estimates the time-series torque and rotation speed required for the motors 3A, 3B while traveling along the travel route, based on the travel driving force information and vehicle speed information.

[0040] Specifically, motor operation estimator 14 converts the driving force into motor torque and converts the vehicle speed into motor rotation speed. If a combination of motor torque and rotation speed is defined as a motor operating point, motor operation estimator 14 estimates the motor operating point in a time series. Information consisting of the motor operating points in a time series is defined as motor operation estimation information, and motor operation estimator 14 estimates the motor operation estimation information.

[0041] It should be noted that the motor operation estimation unit 14 estimates the transition of the operating point based on vehicle speed information (time series transition of vehicle speed) and driving force information (time series transition of driving force). However, since the transition state until a certain driving force and vehicle speed are reached differs depending on the accelerator operation of the driver, the motor operation estimation unit 14 may estimate the transition of the motor's operating point by further taking into account the characteristics of the accelerator operation of each driver.

[0042] Specifically, the driving mode control device 10 stores and accumulates operation history information indicating the history of transitions of the operating point according to the accelerator operation for each driver in a predetermined storage device. The motor operation estimator 14 identifies the driver by a known method such as linking with a mobile terminal or face recognition, and estimates the transition of the operating point of the motor based on the vehicle speed information and driving force information while referring to the operation history information of the identified driver.

[0043] In step S5, the efficiency calculation unit 15 refers to motor efficiency information that associates operating points formed by combinations of the motor torque and rotation speed with efficiency values ​​of the motor, and obtains time-series efficiency values ​​when the driving route is driven in each driving mode based on the motor operation estimation information.

[0044] FIG. 5 is a diagram showing an example of motor efficiency information that associates an operating point of a motor, which is a combination of the rotation speed and torque of the motor, with a motor efficiency value. The efficiency of a motor depends on the rotation speed and torque. In the example shown in FIG. 5, for example, the efficiency value of the operating point (r1, t1) is 95%. In this way, the efficiency calculation unit 15 can uniquely obtain the efficiency value based on the operating point, which is composed of the rotation speed and torque, by referring to the motor efficiency information.

[0045] Generally, high efficiency points, which are operating points with high efficiency, tend to exist in a medium rotation speed region and in a medium to high torque (load) region. Therefore, when the frequency of operation at low rotation speed and low torque operating points is high, fuel economy and power efficiency tend to deteriorate.

[0046] In the example of the electric vehicle V of this embodiment, the second operation mode in which the electric vehicle V is driven by the two motors 3A and 3B may be less efficient than the first operation mode in which the electric vehicle V is driven by one motor because the torque required for each motor is smaller than that required for the first operation mode in which the electric vehicle V is driven by one motor. The operation mode control device 10 of this embodiment determines and controls the operation mode to realize more efficient operation while satisfying the required driving force and taking into account the efficiency characteristics of the motors.

[0047] In addition, in the case where the electric vehicle V is equipped with a generator, the efficiency value associated with each operating point in the motor efficiency information exemplified in FIG. 5 may be a value that takes into account the efficiency of the generator. For example, in the case where the generator is configured by a fuel cell consisting of an FC stack, in the FC stack, the greater the current, the greater the loss due to the influence of concentration overvoltage and resistance overvoltage. In addition, in the air compressor, which is an auxiliary of the FC stack and accounts for a large portion of the total power consumption, the greater the output, the greater the loss (consumption) power. Therefore, the FC stack tends to be more efficient when the load is low, but in the case of an extremely low load, the auxiliary operation may be performed to control the state of the FC stack, so that a high efficiency point may exist on the low load side. In addition, in the motor efficiency information exemplified in FIG. 5, the efficiency value associated with each operating point may be a value that takes into account the magnitude of the regenerative energy efficiency.

[0048] Then, the efficiency calculation unit 15 calculates a total efficiency value for each operation mode based on the time-series efficiency values ​​acquired based on the motor operation estimation information indicating the transition of the operating point in a time series. Specifically, the efficiency calculation unit 15 calculates an aggregate value of the time-series efficiency values ​​as the total efficiency value. For example, the efficiency calculation unit 15 may calculate the sum of the time-series efficiency values ​​as the total efficiency value, or may calculate the average of the time-series efficiency values ​​as the total efficiency value.

[0049] In step S6, the operation mode determination unit 16 determines the operation mode having the highest efficiency indicated by the total efficiency value as the default operation mode. In this embodiment, the operation mode determination unit 16 determines either the first operation mode or the second operation mode as the default operation mode.

[0050] In step S7, the driving control unit 17 controls and drives the electric vehicle V in the default driving mode determined in step S6.

[0051] The above-described processes in steps S1 to S7 are essential processes in the operation mode control method of this embodiment, whereas the processes in step S8 and onward are optional processes.

[0052] In step S8, the specific event detection unit 18 judges whether or not a specific event set in advance has been detected during driving along the driving route. FIG. 6 is a diagram showing an example of specific event detection time control information that associates a specific event with a driving mode control when the specific event is detected. The specific event detection time control information is stored in, for example, an external server or a storage device provided in the driving mode control device 10. That is, in this embodiment, the specific event detection unit 18 attempts to detect a specific event included in the specific event detection time control information. The specific event detection unit 18 can detect various specific events by a known method based on obtaining control information indicating various driving states managed by the ECU, obtaining position information, matching the driving route information with the position information, referring to information input by the driver, and the like.

[0053] For example, the specific event detection unit 18 can detect the restart of the electric vehicle from a stopped state by acquiring information such as a speed change of a predetermined value or more, the magnitude of the torque change rate, and the difference in load on each axle, etc. Also, for example, the specific event detection unit 18 can detect entry onto an uphill or downhill road by matching the position information acquired by the GPS device with gradient data included in the map information, and by using an acceleration sensor, a gyro sensor, etc.

[0054] Also, for example, the specific event detection unit 18 can detect an event of change in the travel route by acquiring information such as a change in the destination input and a re-search for the travel route by the travel route navigation system, etc. Also, for example, the specific event detection unit 18 can detect an event of change in vehicle weight by acquiring information such as a change in vehicle weight detected by the vehicle weight sensor 7 provided on the axle.

[0055] If a specific event is detected, the process proceeds to step S9, whereas if a specific event is not detected, the process proceeds to step S16.

[0056] In step S9, the specific event detection unit 18 determines whether or not there is a specific driving mode associated with the detected specific event. According to the example shown in FIG. 6, if it is detected in step S8 that the traveling route is an "uphill road", the specific event "uphill road" is associated with a specific driving mode, "second driving mode", as a driving mode control, so the specific event detection unit 18 determines that there is a specific driving mode associated with the detected specific event. In addition, if it is detected that the control state of the electric vehicle V is "restarting from a stopped state", the specific event "restarting from a stopped state" is not associated with a specific driving mode in the driving mode control, so the specific event detection unit 18 determines that there is no specific driving mode associated with the detected specific event.

[0057] If it is determined that there is a specific driving mode associated with the detected specific event, the process proceeds to step S10. On the other hand, if it is not determined that there is a specific driving mode associated with the detected specific event, the process proceeds to step S11.

[0058] 6, the specific events "change in driving route" and "change in vehicle weight" are associated with the driving mode control "re-determination." When the specific event detection unit 18 detects the specific events "change in driving route" and "change in vehicle weight," the driving mode control device 10 may perform a process of determining a default driving mode shown in steps S1 to S6 for the remaining driving route, and control the electric vehicle V in the determined default driving mode to operate the remaining driving route.

[0059] In step S10, the driving control unit 17 controls the electric vehicle V in a driving mode associated with the detected specific event.

[0060] In step S11, the efficiency calculation unit 15 calculates a specific section total efficiency value, which is a time-series efficiency value in a specific event section, which is a section of a travel route corresponding to a specific event, for each driving mode. That is, the efficiency calculation unit 15 calculates a total efficiency value for each driving mode in traveling in the specific event section by processing similar to the processing in steps S1 to S5, with the specific event section as the travel route.

[0061] In step S12, the operation mode determination unit 16 determines whether the specific event section operation mode, which is the operation mode with the highest total efficiency value in traveling through the specific event section calculated in step S11, is different from the default operation mode. If it is determined that the specific event section operation mode is different from the default operation mode, the process proceeds to step S13. On the other hand, if it is determined that the specific event section operation mode is different from the default operation mode, the process proceeds to step S16.

[0062] In step S13, the driving control unit 17 controls the electric vehicle V in a specific event section driving mode while traveling in the specific event section. When the specific event section driving mode is a first driving mode in which the electric vehicle V is driven by one motor system, the driving mode may be changed to the first driving mode only when the maximum driving force in the first driving mode satisfies the driving force required for traveling in the specific event section.

[0063] In step S14, the specific event detection unit 18 determines whether or not traveling through the specific event section has ended. For example, the specific event detection unit 18 can detect the end of the specific event section during starting acceleration by acquiring information such as a speed change equal to or greater than a predetermined value, the magnitude of the torque change rate, and the difference in load on each axle. In addition, for example, the specific event detection unit 18 can detect the end of an uphill or downhill road by matching position information acquired by a GPS device with gradient data included in map information, and by using an acceleration sensor, a gyro sensor, or the like.

[0064] If it is determined that the travel through the specific event section has ended, the process proceeds to step S15. On the other hand, if it is not determined that the travel through the specific event section has ended, the determination process of step S14 is repeated.

[0065] In step S15, the driving control unit 17 returns from the changed driving mode to the default driving mode and controls the electric vehicle V. Note that in step S15, instead of returning to the default driving mode, the driving mode determination unit 16 may perform a process similar to the process of determining the default driving mode shown in steps S1 to S6 based on the driving route information of the remaining driving route, and determine the default driving mode for the remaining driving route. Then, the driving control unit 17 may control the electric vehicle V in the default driving mode determined for the remaining driving route.

[0066] In step S16, the driving control unit 17 judges whether or not the operation of the travel route has ended. If it is judged that the operation of the travel route has ended, the process ends. On the other hand, if it is not judged that the operation of the travel route has ended, the process returns to step S8.

[0067] Next, we will explain the axle control associated with the drive mode control when the electric vehicle V has a lift axle mechanism. The lift axle mechanism is a mechanism that performs lift control to keep the wheels of one of the first and second axles of the electric vehicle V from touching the ground, and performs ground contact control to keep the wheels of the other axle from touching the ground.

[0068] The axle state control unit 19 is a functional unit that controls the first and second axles to either lift control or ground contact control. Specifically, the axle state control unit 19 realizes a lift axle mechanism by sending an instruction signal to a lift control valve for lifting or grounding each axle.

[0069] The axle state control unit 19 may perform levitation control of either the first axle or the second axle when the driving control unit 17 controls the electric vehicle V in the first driving mode in which the electric vehicle V is driven by a single motor. In this manner, by performing levitation control of either the first axle or the second axle, it is possible to reduce the running resistance caused by the rolling resistance of the tires, and it is possible to improve fuel efficiency. In addition, the axle state control unit 19 may perform ground contact control of both the first axle and the second axle when the driving control unit 17 controls the electric vehicle V in the second driving mode in which the electric vehicle V is driven by a dual motor.

[0070] The axle state control unit 19 may also store at least one of the number of times and the time for which the lift-up control and the ground contact control are performed for each of the first and second axles as control history information. In this case, when the electric vehicle V is controlled in the first operation mode by the operation control unit 17, the axle state control unit 19 may select an axle to be subjected to lift-up control from the first and second axles so that there is less bias in the number of times or the time for which the ground contact control is performed. By selecting the axle to be subjected to lift-up control in this manner, it is possible to prevent bias in the life span of the unit consisting of each axle due to tire wear during ground contact control, etc.

[0071] The axle state control unit 19 may also obtain load information indicating the load on each of the first axle and the second axle from the vehicle weight sensor 7. In this case, when the electric vehicle V is controlled in the first operation mode by the operation control unit 17, the axle state control unit 19 may select, from the first axle and the second axle, an axle with a smaller load indicated by the load information, as an axle to be subjected to levitation control. By selecting the axle to be subjected to levitation control in this manner, the load distributed to both the first and second axles can be biased to one of the axles, thereby improving the traction of the axle subjected to ground contact control.

[0072] As described above, in the driving mode control device 10 of this embodiment, a time series of motor torque and rotation speed are estimated based on information on a time series of driving force required for traveling a traveling route and a scheduled time series of vehicle speed. A time series efficiency value in each driving mode is acquired based on the estimated motor torque and rotation speed, and a total efficiency value for each driving mode is calculated based on the time series efficiency value. Then, the driving mode with the highest total efficiency value is determined as the default driving mode. Therefore, it is possible to travel the traveling route in a driving mode with a higher efficiency in motor operation.

[0073] The present invention has been described in detail above based on the embodiments. However, the present invention is not limited to the above embodiments. Various modifications of the present invention are possible without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0074] 1...battery, 3...motor system, 3A, 3B...motors, 6...wheels, 7...vehicle weight sensor, 10...driving mode control device, 11...driving route information acquisition unit, 12...vehicle speed information acquisition unit, 13...driving force information acquisition unit, 14...motor operation estimation unit, 15...efficiency calculation unit, 16...driving mode determination unit, 17...driving control unit, 18...specific event detection unit, 19...axle state control unit, V...electric vehicle.

Claims

1. A driving mode control device for an electric vehicle having a battery and a plurality of motor systems, the driving mode for driving a predetermined travel route being determined from a plurality of driving modes each of which defines a number of motor systems to be driven, a driving force information acquisition unit that acquires driving force information indicating a time series of driving force required for traveling the travel route; a vehicle speed information acquisition unit that acquires information on a time series of a vehicle speed expected during traveling along the travel route as vehicle speed information; a motor operation estimating unit that estimates a time series torque and a rotation speed required for the motor while traveling along the traveling route based on the traveling drive force information and the vehicle speed information; an efficiency calculation unit that refers to motor efficiency information that associates the torque and rotation speed of the motor with an efficiency value of the motor, acquires a time-series efficiency value when the driving route is driven in each driving mode based on motor operation estimation information that is information on the estimated time-series torque and rotation speed of the motor, and calculates a total efficiency value for each driving mode based on the acquired time-series efficiency value; an operation mode determination unit that determines an operation mode having the highest efficiency indicated by the total efficiency value as a default operation mode; a driving control unit that controls the electric vehicle in the default driving mode, the electric vehicle has a lift axle mechanism that can perform lift control to lift off one of the first and second axles so that the wheels do not touch the ground, and can perform ground contact control to ground the wheels of the other axle, The number of motor systems is two, The operation modes include a first operation mode in which the motor is driven by one system, and a second operation mode in which the motor is driven by two systems, The operation mode control device includes: and an axle state control unit that controls the first axle and the second axle to either the levitation control or the ground contact control, and that controls one of the first axle and the second axle to levitation control when the electric vehicle is controlled by the operation control unit in the first operation mode. Operation mode control device.

2. the driving force information acquisition unit calculates the driving force based on a time-series running resistance calculated using at least a vehicle weight of the electric vehicle and a gradient of the traveling route; The operation mode control device according to claim 1 .

3. The vehicle speed information acquisition unit A legal speed limit associated with the travel route is acquired as the vehicle speed information; Acquire the vehicle speed information by referring to travel history information in which information on the vehicle speed of a vehicle that has traveled the travel route is accumulated, or acquiring, as the vehicle speed information, a vehicle speed of the vehicle traveling along the travel route, the vehicle speed being calculated based on at least one of information indicating a current state of traffic volume along the travel route and information indicating a current state of a required time for the vehicle traveling along the travel route; The operation mode control device according to claim 1 or 2.

4. a specific event detection unit that detects a specific event that is set in advance while the vehicle is traveling along the travel route; the efficiency calculation unit calculates, when the specific event is detected, a specific section total efficiency value, which is a time-series efficiency value in a specific event section corresponding to the specific event, for each of the operation modes; The operation mode determination unit determines an operation mode having the highest specific section total efficiency value as a specific event section operation mode for traveling through the specific event section, The driving control unit controls the electric vehicle in the specific event section driving mode during traveling in the specific event section. The operation mode control device according to any one of claims 1 to 3.

5. The axle state control unit is At least one of the number of times and the time for which the lift-off control and the ground contact control are performed for each of the first axle and the second axle is stored as control history information, selecting an axle to be subjected to the lift control from the first axle and the second axle such that a bias in the number of times or time for which the ground contact control is performed is reduced when the electric vehicle is controlled in the first operation mode by the operation control unit. The operation mode control device according to any one of claims 1 to 4.

6. The axle state control unit is acquiring load information indicative of a load on each of the first axle and the second axle; When the electric vehicle is controlled in the first operation mode by the operation control unit, an axle having a smaller load indicated in the load information, out of the first axle and the second axle, is selected as an axle to be subjected to the levitation control. The operation mode control device according to any one of claims 1 to 4.

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