JP2022049731A - Hybrid drive device - Google Patents

Abstract

To provide a hybrid drive device that can easily improve the efficiency of traveling in an automobile vehicle speed mode in which vehicle speed is automatically adjusted.SOLUTION: A hybrid drive device is equipped with an internal combustion engine, an electric motor, a transmission that can transmit total power sent from the internal combustion engine and the electric motor to driving wheels by changing a transmission ratio thereof, and a control portion that controls the rotation speed of the internal combustion engine, the rotation speed of the electric motor, and a control portion controlling the transmission ratio of a transmission. The control portion sets one or more specific engine operation areas from optional engine operation areas, sets a plurality of specific motor operation areas included in a positive/negative torque area from optional motor operation areas, selects one of a plurality of combinations of the specific engine operation areas and the specific motor operation areas, according to a charging residual amount of a traveling battery, in an automobile speed mode in which vehicle speed is automatically adjusted to drive the internal combustion engine and the electric motor with the selected combination.SELECTED DRAWING: Figure 6

Description

The present invention relates to a hybrid drive device including an internal combustion engine and an electric motor.

Conventionally, there is an electric vehicle provided with a vehicle speed mode (for example, a cruise control mode) in which a control unit automatically adjusts a vehicle speed while traveling without an accelerator operation by a driver. Patent Document 1 describes a control for maintaining a charge / discharge balance of a traveling battery during traveling in an automobile speed mode.

Japanese Unexamined Patent Publication No. 2000-175306

In the vehicle speed mode, it is unlikely that the required torque will change drastically. Therefore, highly efficient driving can be expected to improve fuel efficiency or electricity cost. However, there is room for improvement in terms of efficiency in the conventional vehicle speed mode driving system.

An object of the present invention is to provide a hybrid drive device that can easily improve driving efficiency in a vehicle speed mode in which a vehicle speed is automatically adjusted.

The invention according to claim 1 is
An internal combustion engine that operates in any engine operating range defined by two parameters, rotational speed and torque,
An electric motor that operates in any motor operating range defined by two parameters, rotational speed and torque, and
A traveling battery that stores the electric power supplied to the electric motor,
A transmission capable of transmitting the total power transmitted from the internal combustion engine and the electric motor to the drive wheels by changing the gear ratio.
A control unit that controls the rotation speed of the internal combustion engine, the rotation speed of the electric motor, and the gear ratio of the transmission.
Equipped with
The control unit
One or more specific engine operating areas are set from the arbitrary engine operating areas, and the specific engine operating areas are set.
A plurality of specific motor operating regions including one or a plurality of motor operating regions included in a positive torque region and one or a plurality of motor operating regions included in a negative torque region from the arbitrary motor operating regions. And set
In the vehicle speed mode in which the vehicle speed is automatically adjusted, one combination is selected from a plurality of combinations of the specific engine operating region and the specific motor operating region based on the remaining charge of the traveling battery. It is a hybrid drive device characterized in that the operating area of an internal combustion engine and the operating area of the electric motor are switched to one selected combination.

The invention according to claim 2 is the hybrid drive device according to claim 1.
The one or more specific engine operating regions include a region in which the efficiency of the internal combustion engine is 75% or more of the maximum efficiency of the internal combustion engine.
The plurality of specific motor operating regions are characterized in that the efficiency of the electric motor includes a region of 75% or more of the maximum efficiency of the electric motor.

The invention according to claim 3 is the hybrid drive device according to claim 1 or 2.
In the vehicle speed mode in which the vehicle speed is automatically adjusted, the control unit has the specific engine operating region and the specific motor operating region based on the difference between the target vehicle speed and the vehicle speed and the remaining charge of the traveling battery. It is characterized by selecting a combination of.

The invention according to claim 4 is the hybrid drive device according to any one of claims 1 to 3.
In the vehicle speed mode in which the vehicle speed is automatically adjusted, the control unit causes the suppression of the increase in the remaining charge and the request for the decrease in the vehicle speed, which cannot be realized by switching the combination of the specific engine operating region and the specific motor operating region. In that case, the driving mode is switched to another mode.

The invention according to claim 5 is the hybrid drive device according to any one of claims 1 to 4.
In the vehicle speed mode in which the vehicle speed is automatically adjusted, the control unit suppresses a decrease in the remaining charge and a request for an increase in the vehicle speed, which cannot be realized by switching the combination of the specific engine operating region and the specific motor operating region. When it occurs, it is characterized by switching the traveling mode to another mode.

According to the present invention, the control unit sets one or a plurality of specific engine operating regions and a plurality of specific motor operating regions including a positive torque region and a negative torque region, and in the vehicle speed mode, the control unit sets one or a plurality of specific engine operating regions. From the plurality of combinations of the specific engine operating area and the specific motor operating area described above, one combination is selected according to the vehicle speed and the remaining charge of the traveling battery, and the operating areas of the internal combustion engine and the electric motor are selected. It switches between the selected specific engine operating area and the specific motor operating area. Therefore, while traveling in the vehicle speed mode, the internal combustion engine operates in the specific engine operating region, the electric motor operates in the specific motor operating region, and the specific engine operating region and the specific motor operating region are set in efficient places. By doing so, highly efficient driving can be realized.

Further, according to the present invention, the plurality of specific motor operating regions include a motor operating region included in a positive torque region and a motor operating region included in a negative torque region, and the control unit is a traveling battery. The combination of the specific engine operating area and the specific motor operating area is selected according to the remaining charge. Therefore, it is possible to switch so that the remaining charge of the traveling battery does not become excessive or insufficient for a long period of time, and the vehicle speed mode that realizes highly efficient traveling can be continued for a long time. Therefore, the fuel consumption or the electricity cost of the electric vehicle can be further improved.

It is a block diagram which shows the electric vehicle and the hybrid drive device of embodiment of this invention. It is a characteristic graph (A) of an engine and a characteristic graph (B) of a traveling motor. It is a flowchart which shows the procedure of the 1st vehicle speed adjustment process which a traveling control unit executes in an eco-vehicle speed mode. It is a part of the flowchart which shows the procedure of the 2nd vehicle speed adjustment process which a traveling control unit executes in an eco-vehicle speed mode. It is a part of the flowchart which shows the procedure of the 2nd vehicle speed adjustment process which a traveling control unit executes in an eco-vehicle speed mode. It is a time chart explaining the driving example 1 of the eco-vehicle speed mode. It is a time chart explaining the driving example 2 of the eco-vehicle speed mode.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an electric vehicle and a hybrid drive device according to an embodiment of the present invention. The electric vehicle 1 of the present embodiment is a HEV (Hybrid Electric Vehicle), and includes a drive wheel 2, an engine 3 and a traveling motor 5 that output power to the drive wheel 2, and an auxiliary machine 4 for driving the engine 3. , The inverter 6 that drives the traveling motor 5, the traveling battery 7 that stores the power supplied to the traveling motor 5, and the transmission 8 that shifts the power of the engine 3 and the traveling motor 5 and transmits them to the drive wheels 2. A vehicle speed sensor 11 that detects a vehicle speed, a peripheral sensor 12 such as a camera, a radar, or a sonar that detects a surrounding vehicle, and a travel control unit 31 that controls travel are provided.

The engine 3 is an internal combustion engine, and the traveling motor 5 is an electric motor. The traveling motor 5 is capable of power running operation and regenerative operation. During the regenerative operation, the power is converted into electric power, and the traveling battery 7 is charged via the inverter 6. Information on the SOC (State of Charge) of the traveling battery 7 is sent to the traveling control unit 31. The transmission 8 is a stepless transmission whose gear ratio can be changed by control. The travel control unit 31 corresponds to an example of the control unit according to the present invention.

The electric vehicle 1 further includes a driving operation unit 21 that receives a driving operation from the driver, a mode changeover switch 22 that receives a driving mode switching operation from the driver, and a target that allows the driver to input a target speed in the vehicle speed mode. It is provided with a vehicle speed setting operation unit 23. The operation operation unit 21 includes an accelerator operation unit, a brake operation unit, and a steering wheel.

Among the above configurations, the engine 3, the auxiliary machine 4, the traveling motor 5, the inverter 6, the traveling battery 7, the transmission 8, the vehicle speed sensor 11, the surrounding sensor 12, the mode changeover switch 22, the target vehicle speed setting operation unit 23, and the traveling The control unit 31 corresponds to the hybrid drive device 1A of the present embodiment.

The travel control unit 31 includes one ECU (Electronic Control Unit) or a plurality of ECUs that operate in cooperation with each other, and controls the auxiliary machine 4, the inverter 6, and the transmission 8. The vehicle speed value detected by the vehicle speed sensor 11 and the detection information of surrounding vehicles detected by the surrounding sensor 12 are input to the traveling control unit 31.

In the normal travel mode, the operation operation signal including the operation amount signals of the accelerator operation unit and the brake operation unit is sent to the travel control unit 31. The travel control unit 31 operates the auxiliary equipment 4 and the inverter 6 so as to generate an acceleration torque or a deceleration torque according to the above-mentioned operation amount. By controlling the traveling control unit 31 in this way, traveling according to the driving operation is realized.

The traveling mode that can be selected in the electric vehicle 1 includes a vehicle speed mode in which the vehicle speed is automatically adjusted, in addition to the normal traveling mode. In the vehicle speed mode, the target vehicle speed is set in the travel control unit 31, and the vehicle speed is adjusted to the target vehicle speed without the driver operating the accelerator operation unit and the brake operation unit. The target vehicle speed may be set by the driver via the target vehicle speed setting operation unit 23, may be set by the travel control unit 31 so as to follow the vehicle in front, or may be combined. .. The travel control unit 31 can estimate the speed of the vehicle in front from the information of the surrounding sensor 12. Further, the target vehicle speed may be set with a width, for example, from 60 km / h to 100 km / h when traveling on an empty highway.

<Operating characteristics of engine and traction motor>
FIG. 2A shows an engine characteristic graph. In this characteristic graph, the solid line is the characteristic line showing the efficiency value, and the alternate long and short dash line is the characteristic line showing the power. The engine 3 operates in an arbitrary operating region (arbitrary region on the characteristic graph) defined by two parameters of torque and rotational speed. It should be noted that the arbitrary operation region includes a stop region where the torque is zero and the rotation speed is zero. By changing the state of the auxiliary machine 4 (throttle opening, fuel injection amount, ignition timing, etc.) and the load acting on the engine 3, the engine 3 can control in which operating region it is operated. .. The load of the engine 3 includes a load actuated by the drive wheels 2 and a load actuated by the traveling motor 5. When the traveling motor 5 is regeneratively operated, the load applied by the traveling motor 5 becomes a positive value, and when the traveling motor 5 is power-running, the load applied by the traveling motor 5 becomes a negative value. Therefore, the load of the engine 3 can be controlled to an arbitrary value by controlling the operating state of the traveling motor 5 and the gear ratio of the transmission 8. Therefore, the travel control unit 31 can drive the engine 3 in a predetermined operating region.

The operating region of the engine 3 includes a region having high efficiency (thermal efficiency) and a region having low efficiency. The characteristic graph of FIG. 2A shows that the efficiencies of a series of operating points connected by the solid characteristic lines are the same. The central region P1 of the orbiting characteristic line is the most efficient operating region.

FIG. 2B is a characteristic graph of the traveling motor. In this characteristic graph, the characteristic line represents the efficiency value. The traveling motor 5 operates in an arbitrary operating region (arbitrary region on the characteristic graph) defined by two parameters of torque and rotation speed. The positive torque region is the power running region, and the negative torque region is the regenerative operation region. It is assumed that the arbitrary operation region includes a region where the torque is zero and the rotation speed is arbitrary. By changing the operation of the inverter 6 and the load acting on the traveling motor 5, the traveling motor 5 can control which operating region the traveling motor 5 operates in. The load acting on the traveling motor 5 can be controlled to an arbitrary value by changing the gear ratio of the transmission 8 and the output torque of the engine 3. Therefore, the travel control unit 31 can drive the travel motor 5 in a predetermined operating region.

The operating region of the traveling motor 5 includes a region having high efficiency (energy efficiency) and a region having low efficiency. The characteristic graph of FIG. 2B shows that the efficiencies of a series of operating points connected by the characteristic lines are the same. The central regions P11 and P12 of the orbiting characteristic line are the operating regions with the highest efficiency. The region P13 is an operating region where the motor torque is zero, and is realized by the zero torque operation of the inverter 6.

<Vehicle speed mode>
In the present embodiment, the vehicle speed mode is an eco-mode that can further reduce fuel consumption or electricity cost (hereinafter, also referred to as "eco-vehicle speed mode") and a normal mode in which eco-mode processing is not performed (hereinafter, "normal vehicle speed mode"). Also called) and. In the eco-vehicle speed mode, the travel control unit 31 limits the operating region of the engine 3 and the operating region of the traveling motor 5 so as to be a preset specific engine operating region and a predetermined specific motor operating region. Then, the engine 3 and the traveling motor 5 are driven. The eco-vehicle speed mode corresponds to an example of the vehicle speed mode according to the present invention.

The preset specific engine operating region includes one operating region P1 (FIG. 2A) having the highest efficiency. The specific engine operating region P1 is, for example, a region where the torque is 100 [Nm] and the rotation speed is a predetermined value. The setting pattern of the specific engine operating area is not limited to the above example. For example, in a region with high efficiency (for example, a region of 75% or more of the maximum efficiency), a plurality of operating regions having different torques or rotational speeds may be set as specific engine operating regions. Further, the specific engine operating region may include a stop region where the torque is zero and the rotation speed is zero. When a plurality of specific engine operating regions are set, the plurality of specific engine operating regions may be regions discrete from each other.

As shown in FIG. 2B, the specific motor operating region has an operating region P11 having the highest efficiency in the positive torque region, an operating region P12 having the highest efficiency in the negative torque region, and a rotation speed at zero torque. An arbitrary operating area P13 is included. On the other hand, the specific motor operating region P11 is, for example, a region where the torque is 30 [Nm] and the rotation speed is a predetermined value. The other specific motor operating region P12 is, for example, a region where the torque is −30 [Nm] and the rotation speed is a predetermined value. The setting pattern of the specific motor operating region is not limited to the above example. For example, in a region of high efficiency (for example, a region of 75% or more of the maximum efficiency), more operating regions having different torques or rotational speeds may be set as specific motor operating regions. The plurality of specific motor operating regions are operating regions that are discrete from each other.

In the eco-vehicle speed mode, the travel control unit 31 selects any combination of a plurality of combinations of the specific engine operating region and the specific motor operating region. In the above example, as shown in the following combination table, the first combination to the third combination exist, and the traveling control unit 31 selects one combination from the first combination to the third combination.

Once one combination is selected, the travel control unit 31 drives the engine 3 and the travel motor 5 in the operating region of the selected combination. Further, the traveling control unit 31 switches the combination to be selected according to the SOC of the traveling battery 7 and the vehicle speed, thereby balancing the SOC so that the SOC of the traveling battery 7 does not become excessive or deficient. Adjust the vehicle speed.

<First vehicle speed adjustment process>
FIG. 3 is a flowchart showing a first vehicle speed adjustment process executed by the traveling control unit in the eco-vehicle speed mode. The first vehicle speed adjustment process is executed when a wide target vehicle speed is set, for example, when traveling on an empty highway.

When the travel mode is switched to the eco-vehicle speed mode by setting a wide target vehicle speed, the travel control unit 31 starts the first vehicle speed adjustment process. When the first vehicle speed adjustment process is started, the travel control unit 31 first initializes including reading the maximum and minimum values of the target vehicle speed and initial selection of the operating region of the engine 3 and the travel motor 5. Perform processing (step S1). The operating region initially selected in the initialization process is, for example, the operating region of the second combination in which discharge is performed when the SOC of the traveling battery 7 is 50% or more, and when the SOC is less than 50%. It is the operating area of the third combination in which charging is performed.

After performing the initialization process, the travel control unit 31 determines whether the SOC of the travel battery 7 exceeds the upper threshold value (step S2) or falls below the lower threshold value (step S3), and the current vehicle speed is the highest target vehicle speed. It is determined whether the value is exceeded (step S4), the value is below the minimum value (step S5), or the target vehicle speed is updated (step S6). The upper threshold value of the SOC is set to a value lower than the upper limit value of the SOC, and the lower threshold value of the SOC is set to a value higher than the lower limit value of the SOC.

Then, when it is determined in step S2 that the SOC exceeds the upper threshold value, the travel control unit 31 switches the operating region of the engine 3 and the traveling motor 5 to the operating region of the second combination in which discharge is performed (step S8). If it is determined in step S3 that the SOC has fallen below the lower threshold value, the travel control unit 31 switches the operating region of the engine 3 and the traveling motor 5 to the operating region of the third combination in which charging is performed (step S9). With such control, the SOC can be maintained between the lower threshold and the upper threshold.

Further, when the discrimination results of steps S2 to S6 are all NO, or when the selection of the operation area is switched in steps S8 and S9, the traveling control unit 31 is currently selected. The auxiliary machine 4 and the inverter 6 are controlled so that the engine 3 and the traveling motor 5 operate (step S7). Then, the traveling control unit 31 returns the processing to the discrimination processing from step S2.

On the other hand, if it is determined in step S4 that the vehicle speed has exceeded the maximum value of the target vehicle speed, in step S5 it is determined that the vehicle speed has fallen below the minimum value of the target vehicle speed, or if the target vehicle speed is updated in step S6. Once determined, the travel control unit 31 switches the travel mode to the normal vehicle speed mode (step S10), and ends the first vehicle speed adjustment process. The target vehicle speed can be changed by the driver operating the target vehicle speed setting operation unit 23. Further, the travel control unit 31 updates the target vehicle speed so as to follow the vehicle in front when there is a vehicle in front, based on the detection information of the surrounding sensor 12.

By the first vehicle speed adjustment process described above, the operating regions of the engine 3 and the traveling motor 5 are charged with the operating regions of the second combination to be discharged according to the SOC of the traveling battery 7 while traveling in the eco-vehicle speed mode. Since it can be switched to the operation region of the third combination, it is possible to realize highly efficient running while maintaining the SOC between the upper threshold value and the lower threshold value. When the target vehicle speed is wide, for example, from 60 km / h to 100 km / h, even if the operating area is switched based on the SOC in steps S8 and S9, the vehicle continues to travel within the target vehicle speed range for a long period of time. can. Then, when the target vehicle speed narrows due to the appearance of a vehicle in front, or when the maximum or minimum value of the target vehicle speed is reached, the driving mode can be switched from the eco-vehicle speed mode to another mode. , The electric vehicle 1 can continue to travel in response to these situations.

<Second vehicle speed adjustment process>
4 and 5 are flowcharts showing a second vehicle speed adjustment process executed by the traveling control unit in the eco-vehicle speed mode. The second vehicle speed adjustment process is executed when the target vehicle speed is set at one point or in a narrow width in the eco-vehicle speed mode.

In the second vehicle speed adjustment process, an upper threshold value, a lower threshold value, a high SOC band, and a low SOC band of the SOC are introduced in advance for adjusting the SOC. The upper threshold value of the SOC is set to a value lower than the upper limit value of the SOC, and the lower threshold value of the SOC is set to a value higher than the lower limit value of the SOC. The high SOC band means a region from a value lower to a higher value by hysteresis from the upper threshold value, and for example, the upper threshold value of SOC is 80% and the high SOC band is 75% to 100%. The low SOC band means a region from a value higher to a lower value by hysteresis from the lower threshold value, and for example, the lower threshold value of SOC is 20%, the low SOC band is 0% to 25%, and the like.

When the second vehicle speed adjustment process is started after shifting to the eco-vehicle speed mode, the travel control unit 31 first sets the upper vehicle speed threshold value and the lower vehicle speed threshold value by adding the tolerance to the target vehicle speed, and the engine. Initialization processing such as selecting the first combination as the initial operating region of the traveling motor 3 and the traveling motor 5 is performed (step S21).

After performing the initialization process, the travel control unit 31 determines whether the SOC of the travel battery 7 exceeds the upper threshold value (step S22) or falls below the lower threshold value (step S23), or the current vehicle speed is higher than the upper vehicle speed threshold value. It is determined whether it is high (step S24) or lower than the disembarkation speed threshold value (step S25). Here, exceeding the threshold value or falling below the threshold value means that the value is higher than the threshold value across the threshold value, or the value is lower than the threshold value across the threshold value. That is, in the determination in step S22, when the SOC before the predetermined control cycle is equal to or less than the upper limit value and the SOC of the current cycle is higher than the upper limit value, it is determined that the SOC exceeds the upper limit value. In the determination in step S23, when the SOC before the predetermined control cycle is equal to or higher than the lower limit value and the SOC in the current cycle is lower than the lower limit value, it is determined that the SOC is below the lower limit value.

Further, if the travel control unit 31 determines YES in step S24, is the SOC of the travel battery 7 located in the high SOC band after exceeding the upper threshold value (step S26), and further, the vehicle speed is higher than the vehicle speed threshold value. It is determined whether or not the deviation is equal to or greater than the predetermined width (step S27).

Further, if the travel control unit 31 determines YES in step S25, the SOC of the travel battery 7 remains in the low SOC band after falling below the lower threshold value (step S28), or the vehicle speed is lower than the disembarkation speed threshold value. It is determined whether or not the deviation is equal to or greater than the predetermined width (step S29).

Then, the traveling control unit 31 executes the branching process based on the result of the above determination. That is, if YES is determined in step S22, the SOC is high, so the traveling control unit 31 selects the operating region of the second combination as the operating region of the engine 3 and the traveling motor 5 (step S31). If YES is determined in step S23, the SOC is low, so the traveling control unit 31 selects the operating region of the third combination as the operating region of the engine 3 and the traveling motor 5 (step S32).

Further, if it is determined as YES in step S24 and NO in step S26, the SOC is moderate and the vehicle speed is high, so that the traveling control unit 31 selects the operating region of the third combination as the operating region of the engine 3 and the traveling motor 5. (Step S33). Further, if it is determined as YES in step S25 and NO in step S28, the SOC is moderate and the vehicle speed is low, so that the traveling control unit 31 selects the operating region of the second combination as the operating region of the engine 3 and the traveling motor 5. (Step S36).

Further, if it is determined as YES in step S24, YES in step S26, and NO in step S27, the SOC is high and the vehicle speed is high. The operating area is selected (step S34). Further, if it is determined as YES in step S25, YES in step S28, and NO in step S29, the SOC is low and the vehicle speed is low. The operating area is selected (step S37).

Further, if it is determined as YES in step S24, YES in step S26, and YES in step S27, it means that the SOC is high, the vehicle speed is high, and the vehicle speed does not decrease. The vehicle speed mode or the normal traveling mode is switched to (step S35), and the second vehicle speed adjustment process is completed. Further, if it is determined as YES in step S25, YES in step S28, and YES in step S29, it means that the SOC is low and the vehicle speed is low and the vehicle speed does not increase. Therefore, the travel control unit 31 normally sets the travel mode. The vehicle speed mode or the normal traveling mode is switched to (step S38), and the second vehicle speed adjustment process is completed.

The travel control unit 31 is currently selected when the determination results in steps S22 to S25 are all NO, or when it is determined to be YES in any of the determination processes and the operating areas of the engine 3 and the travel motor 5 are switched. The auxiliary machine 4 and the inverter 6 are controlled so that the engine 3 and the traveling motor 5 operate in the operating region (step S41). Subsequently, the travel control unit 31 performs a determination process for determining whether the target vehicle speed is updated (step S42), and if there is an update, updates the ascending / descending speed threshold value and the disembarking speed threshold value according to the updated target vehicle speed. (Step S43), the process is returned to the discrimination process from step S22. The target vehicle speed can be changed by the driver operating the target vehicle speed setting operation unit 23. Further, the travel control unit 31 updates the target vehicle speed to follow the preceding vehicle when the preceding vehicle approaches or moves away based on the detection information of the surrounding sensor 12.

Due to the second vehicle speed adjustment process, the operating regions of the engine 3 and the traveling motor 5 are a plurality of specific engine operating regions and specific motor operating regions according to the SOC of the traveling battery 7 and the vehicle speed while traveling in the eco-vehicle speed mode. Since it can be switched in the combination of the above, it is possible to realize highly efficient driving while suppressing the excess or deficiency of the SOC and the deviation of the vehicle speed from the target vehicle speed. Next, some examples of the running will be illustrated.

<Eco-vehicle speed mode driving example 1>
FIG. 6 also shows the step numbers of the corresponding second vehicle speed adjustment processes (FIGS. 4 and 5) in the explanation of the operation which is the time chart for explaining the traveling example 1 in the eco-vehicle speed mode. In the traveling example 1, the operating areas of the engine 3 and the traveling motor 5 are switched when the vehicle speed becomes higher than the upper vehicle speed threshold value, and the engine 3 and the traveling motor 5 when the SOC of the traveling battery 7 exceeds the upper threshold value. This is an example in which the switching of the operating area is repeated to maintain the SOC and adjust the vehicle speed.

For example, when the operation region of the second combination is initially selected, the SOC is between the upper threshold value and the lower threshold value at the timing t1, and the vehicle speed exceeds the upper vehicle speed threshold value, the operation of the engine 3 and the traveling motor 5 is performed. The region is switched to the operating region of the third combination (steps S24, S26, S33). By this switching, the output torque decreases and charging is performed, so that the vehicle speed decreases and the SOC increases thereafter. Then, at the subsequent timing t2, when the vehicle speed is between the ascending vehicle speed threshold value and the descending vehicle speed threshold value, the SOC exceeds the upper threshold value, so that the operating region of the engine 3 and the traveling motor 5 becomes the operating region of the second combination. It can be switched (steps S22, S31). Then, such operations and processes are repeated, and the traveling is continued.

Although not shown in the driving example, the operation areas of the engine 3 and the traveling motor 5 are switched when the vehicle speed becomes lower than the disembarkation speed threshold value, and the engine when the SOC of the traveling battery 7 falls below the lower threshold value. Even when the switching of the operating area of the traveling motor 5 and the traveling motor 5 is repeated, it is possible to realize traveling in which the maintenance of the SOC and the adjustment of the vehicle speed are continued in the same manner as the traveling example of FIG.

<Driving example 2 in eco-vehicle speed mode>
FIG. 7 is a time chart illustrating driving example 2 in the eco-vehicle speed mode. In the explanation of the operation, the step numbers of the corresponding second vehicle speed adjustment processes (FIGS. 4 and 5) are also described. The driving example 2 shows an example when the vehicle speed is higher than the target vehicle speed and the SOC is also higher while driving in the eco-vehicle speed mode.

At a certain timing t11, when the SOC exceeds the upper threshold value and the operating regions of the engine 3 and the traveling motor 5 are switched to the operating region of the second combination (steps S22 and S31), the vehicle speed is already close to the upper threshold value. After that, when the vehicle speed becomes higher than the upper vehicle speed threshold value, the situation where the SOC is still located in the high SOC band occurs (timing t12). Such a situation can occur when the target vehicle speed changes, such as by following the speed of the vehicle in front. Then, in such a situation, since it is necessary to reduce the vehicle speed without increasing the SOC, it is possible to switch to the operation region of the first combination in which the output torque is slightly low and the charge / discharge is almost zero (steps S24, S26, S27). , S34).

Here, by switching to the operation region of the first combination, the vehicle speed may decrease as shown by the solid line of the period T11. In this case, after that, the SOC becomes high and the vehicle speed becomes low, and the maintenance of the SOC and the adjustment of the vehicle speed can be continued as shown in the traveling example 1.

On the other hand, as shown by the broken line of the period T11, after switching to the operation region of the first combination, the vehicle speed may increase without decreasing depending on the slope of the traveling road surface or the target vehicle speed. In such a case, it is difficult to maintain the SOC and adjust the vehicle speed at the same time, so that the driving mode is switched from the eco-vehicle speed mode to the normal vehicle speed mode or the normal driving mode (timing t13, step S24, S26, S27, S35). Then, by switching the traveling mode, the vehicle speed can be lowered without increasing the SOC.

Although the illustration of the driving example is omitted, even when the vehicle speed is lower than the target vehicle speed and the SOC is also lower, the second vehicle speed adjustment process is performed in a manner similar to the driving example of FIG. It is possible to deal with situations where it is difficult to maintain the SOC and adjust the vehicle speed.

As described above, according to the electric vehicle 1 and the hybrid drive device 1A of the present embodiment, in the eco-vehicle speed mode, the travel control unit 31 has one preset specific engine operation region, a positive torque region, and a negative. One of a plurality of combinations (first combination to third combination) with three specific motor operating regions including a torque region is selected, and the engine 3 and the traveling motor 5 are selected in the operating region of the selected combination. And drive. Therefore, the engine 3 and the traveling motor 5 operate in a preset specific engine operating region and a preset specific motor operating region, and these operating regions are set in a highly efficient region. As a result, highly efficient driving can be realized.

Further, the traveling control unit 31 switches the selection of the combination of operating regions based on the SOC of the traveling battery 7 in the eco-vehicle speed mode. Therefore, it is possible to switch the operating region so as to prevent the SOC from becoming too small or too large, and the duration of the eco-vehicle speed mode can be extended. By lengthening the duration, the fuel consumption or the electricity cost of the electric vehicle 1 can be further improved.

Further, according to the electric vehicle 1 and the hybrid drive device 1A of the present embodiment, the preset specific engine operation region includes the operation region P1 having the highest efficiency of the engine 3, and the preset specific motor operation. The region includes operating regions P11 and P12 having the highest efficiency of the traveling motor 5. By using such an operating region, more efficient driving in the eco-vehicle speed mode is realized. It is not always necessary to include the most efficient operating region in the specific engine operating region and the specific motor operating region. For example, by including the operating region having an efficiency of 75% or more of the maximum efficiency in the operating region selected with high frequency, efficient driving in the eco-vehicle speed mode is realized.

Further, according to the electric vehicle 1 and the hybrid drive device 1A of the present embodiment, in the second vehicle speed adjustment process of the eco-vehicle speed mode, the difference between the target vehicle speed and the vehicle speed and the SOC of the traveling battery 7 are used. , The selection of the combination of operating areas is switched. Therefore, in the eco-vehicle speed mode, traveling is realized in which the vehicle speed is maintained in the vicinity of the target vehicle speed while suppressing the excess or deficiency of the SOC.

Further, according to the electric vehicle 1 and the hybrid drive device 1A of the present embodiment, as shown by the broken line in FIG. 7, when the SOC is located in the high SOC band and the vehicle speed exceeds the vehicle speed threshold. When the operation region of the first combination is selected, but the vehicle speed does not decrease, that is, when both the suppression of the increase in SOC and the request for decrease in vehicle speed cannot be achieved, the travel control unit 31 makes the travel mode eco-friendly. Switch from vehicle speed mode to another mode. Therefore, if the eco-vehicle speed mode is continued, it is possible to prevent the SOC from becoming excessive and the vehicle speed from deviating significantly from the target vehicle speed.

Similarly, according to the electric vehicle 1 and the hybrid drive device 1A of the present embodiment, the operation region of the first combination is selected when the SOC is located in the low SOC band and the vehicle speed becomes lower than the disembarkation speed threshold. However, when the vehicle speed still does not increase, that is, when it is not possible to achieve both the suppression of the decrease in SOC and the demand for increase in vehicle speed, the driving mode is switched from the eco-vehicle speed mode to another mode. Therefore, if the eco-vehicle speed mode is continued, it is possible to prevent the SOC from becoming too small and the vehicle speed from deviating significantly from the target vehicle speed.

The embodiment of the present invention has been described above. However, the present invention is not limited to the above embodiment. For example, the number of preset specific engine operating regions and the position of the regions can be changed in various ways. Further, the number of predetermined motor operating regions and the positions of the regions can be variously changed as long as at least one positive torque region and negative torque region are included. Further, in the above embodiment, an example of a method of selecting one combination from a plurality of combinations of the specific engine operating region and the specific motor operating region is shown in the first vehicle speed adjustment process of FIG. 3 and FIGS. 4 and 5. Although shown in the second vehicle speed adjustment process of the above, these methods are merely examples and do not limit the present invention. Further, in the above embodiment, an example in which the hybrid drive device 1A has two driving modes, a normal vehicle speed mode and an eco-vehicle speed mode, is shown. However, as a driving mode for automatically adjusting the vehicle speed, the eco-vehicle speed is used. It may have only a mode. In addition, the details shown in the embodiment can be appropriately changed without departing from the spirit of the invention.

1 Electric vehicle 2 Drive wheels 3 Engine 4 Auxiliary equipment 5 Driving motor 6 Inverter 7 Driving battery 8 Transmission 11 Vehicle speed sensor 12 Surrounding sensor 21 Driving operation unit 22 Mode changeover switch 23 Target vehicle speed setting operation unit 31 Driving control unit P1 Specific engine Operating area P11, P12, P13 Specific motor operating area

Claims (5)

An internal combustion engine that operates in any engine operating range defined by two parameters, rotational speed and torque,
An electric motor that operates in any motor operating range defined by two parameters, rotational speed and torque, and
A traveling battery that stores the electric power supplied to the electric motor,
A transmission capable of transmitting the total power transmitted from the internal combustion engine and the electric motor to the drive wheels by changing the gear ratio.
A control unit that controls the rotation speed of the internal combustion engine, the rotation speed of the electric motor, and the gear ratio of the transmission.
Equipped with
The control unit
One or more specific engine operating areas are set from the arbitrary engine operating areas, and the specific engine operating areas are set.
A plurality of specific motor operating regions including one or a plurality of motor operating regions included in a positive torque region and one or a plurality of motor operating regions included in a negative torque region from the arbitrary motor operating regions. And set
In the vehicle speed mode in which the vehicle speed is automatically adjusted, one combination is selected from a plurality of combinations of the specific engine operating region and the specific motor operating region based on the remaining charge of the traveling battery. A hybrid drive device characterized in that the operating area of an internal combustion engine and the operating area of the electric motor are switched to one selected combination. The one or more specific engine operating regions include a region in which the efficiency of the internal combustion engine is 75% or more of the maximum efficiency of the internal combustion engine.
The hybrid drive device according to claim 1, wherein the plurality of specific motor operating regions include a region in which the efficiency of the electric motor is 75% or more of the maximum efficiency of the electric motor. In the vehicle speed mode in which the vehicle speed is automatically adjusted, the control unit has the specific engine operating region and the specific motor operating region based on the difference between the target vehicle speed and the vehicle speed and the remaining charge of the traveling battery. The hybrid drive device according to claim 1 or 2, wherein the combination of the above is selected. In the vehicle speed mode in which the vehicle speed is automatically adjusted, the control unit causes the suppression of the increase in the remaining charge and the request for the decrease in the vehicle speed, which cannot be realized by switching the combination of the specific engine operating region and the specific motor operating region. The hybrid drive device according to any one of claims 1 to 3, wherein the traveling mode is switched to another mode in such a case. In the vehicle speed mode in which the vehicle speed is automatically adjusted, the control unit suppresses a decrease in the remaining charge and demands an increase in the vehicle speed, which cannot be realized by switching the combination of the specific engine operating region and the specific motor operating region. The hybrid drive device according to any one of claims 1 to 4, wherein when the occurrence occurs, the traveling mode is switched to another mode.

Images