JP2020132041A - Control device of hybrid vehicle - Google Patents

Abstract

To provide a control device of a hybrid vehicle which can properly select an output mode of an engine and a traveling mode of a drive unit according to requirement power.SOLUTION: When requirement power required to a hybrid vehicle is equal to first prescribed power or lower in the case that a vehicle travels while setting a Hi-mode, a drive mode of an engine is set to a low-output mode, the Hi-mode is maintained, and when the requirement power is equal to second prescribed power or larger which is larger than the first prescribed power, the drive mode of the engine is set to a high-output mode, and the traveling mode is switched to a Lo-mode from the Hi-mode. When the requirement power is larger than the first prescribed power, and lower than the second prescribed power, the drive mode of the engine is set to the low-output mode, and the traveling mode is switched to the Lo-mode from the Hi-mode.SELECTED DRAWING: Figure 8

Description

The present invention relates to an engine whose output characteristics can be changed and a control device for a hybrid vehicle capable of setting a plurality of traveling modes having different torque transmission rates from the engine to the drive wheels via a differential mechanism.

In Patent Document 1, a first planetary gear mechanism having a first rotating element to which an engine is connected, a second rotating element to which a first motor is connected, and a third rotating element are connected to a drive wheel. A second planetary gear mechanism having a fourth rotating element, a fifth rotating element connected to the third rotating element in the first planetary gear mechanism, and a sixth rotating element, and the first rotating element and the sixth rotation. A control device for a hybrid vehicle including a drive device composed of a first clutch mechanism that selectively connects elements and a second clutch mechanism that selectively connects a fourth rotating element and a sixth rotating element. Are listed. The control device of this hybrid vehicle has a Lo mode in which the first clutch mechanism is engaged and the second clutch mechanism is released, and a Hi mode in which the first clutch mechanism is released and the second clutch mechanism is engaged. It is configured so that a fixed stage mode in which one clutch mechanism and a second clutch mechanism are engaged with each other can be set, and switching between Hi mode and Lo mode is executed via the fixed stage mode. However, when each clutch mechanism is a friction type clutch mechanism, switching between Hi mode and Lo mode is configured to be switched by so-called clutch-to-clutch control.

JP-A-2018-187965

In the Hi mode and Lo mode described in Patent Document 1, engine torque can be transmitted to the drive wheels by outputting reaction torque from the first motor. At that time, the reaction force torque required for the first motor in order to maintain the rotation speeds of the engine and the first motor and transmit the engine torque to the drive wheels is larger in the Hi mode than in the Lo mode. In other words, if a high torque is output from the engine, a sufficient reaction torque cannot be output from the first motor, and the engine speed may increase.

On the other hand, when an engine equipped with a turbocharger or an engine that can select an output mode with different output characteristics such as an engine that can change the number of operating cylinders is adopted, the output mode of the engine is changed from low output mode to high output. When the mode is switched, the operating point where the thermal efficiency of the engine is good changes. Therefore, if the output mode of the engine is switched from the low output mode to the high output mode and the thermal efficiency of the engine is controlled to a good driving speed while driving with the Hi mode set, the output torque of the engine increases. Therefore, there is a possibility that sufficient reaction torque cannot be output from the first motor.

The present invention has been made by paying attention to the above technical problems, and an object of the present invention is to provide a hybrid vehicle control device capable of appropriately selecting an engine output mode and a driving device traveling mode according to a required power. Is to be.

In the present invention, in order to achieve the above object, an engine, a motor, a first rotating element to which the engine is connected, a second rotating element to which the motor is connected, and a third rotating element to which the drive wheels are connected are connected. The engine is provided with a differential mechanism having at least three rotating elements with a rotating element, and the engine has a high output mode in which the output torque at a predetermined rotation speed is relatively large when operated at an operating point with good thermal efficiency. At least two operation modes, that is, a low output mode in which the output torque is relatively small, can be switched, and the differential mechanism has a relative torque transmitted from the first rotating element to the third rotating element. A control device for a hybrid vehicle configured to be able to set at least two driving modes, a Lo mode having a large size and a Hi mode in which the torque transmitted from the first rotating element to the third rotating element is relatively small. In the above, a controller for controlling the operation mode and the traveling mode is provided, and the controller is used when the required power to the hybrid vehicle is equal to or less than the first predetermined power when traveling with the Hi mode set. When the low output mode is set and the Hi mode is maintained and the required power is equal to or higher than the second predetermined power larger than the first predetermined power, the high output mode is set and the traveling mode is set to the Hi mode. When the required power is larger than the first predetermined power and less than the second predetermined power, the low output mode is set and the traveling mode is switched from the Hi mode to the Lo mode. It is characterized by being configured as follows.

In the present invention, the differential mechanism is configured so that a fixed stage mode in which the rotation speed ratio between the first rotating element and the third rotating element is a fixed ratio can be further set, and the fixed stage is changed from the Hi mode. With respect to the direction of the reaction force torque output by the motor when the Lo mode is switched via the mode and the Hi mode is set to transmit torque from the engine to the drive wheels. When the Lo mode is set and torque is transmitted from the engine to the drive wheels, the direction of the reaction force torque output by the motor is reversed, and the controller has the Hi mode and the low output mode. When the Lo mode and the high output mode are set from the state in which is set, the magnitude of the reaction force torque due to the torque of the motor is reduced at the time of switching from the Hi mode to the fixed stage mode, and the above The reversing control for reversing the direction of the torque of the motor and the switching control for the output mode of the engine may be executed in an overlapping manner.

According to the present invention, when the required power for the hybrid vehicle is equal to or less than the first predetermined power when traveling with the Hi mode set, the operation mode of the engine is set to the low output mode and the Hi mode is maintained. When the required power is larger than the first predetermined power and is equal to or higher than the second predetermined power, the operation mode of the engine is set to the high output mode and the driving mode is switched from the Hi mode to the Lo mode, and the required power is higher than the first predetermined power. When the power is large and less than the second predetermined power, the operation mode of the engine is set to the low output mode and the driving mode is switched from the Hi mode to the Lo mode. That is, the traveling mode and the operating mode of the engine are selected and set according to the required power of the engine. Therefore, when the operation mode of the engine is switched to the high output mode, the driving mode can be switched to the HV-Lo mode, so that the reaction torque of the motor is insufficient and the engine speed increases excessively or the driving force. It is possible to prevent the situation where there is a shortage.

It is a schematic diagram which shows an example of the hybrid vehicle which can be the object of this invention. It is a block diagram for demonstrating the structure of an electronic control unit (ECU). It is a figure which shows the engaging and disengaging state of the clutch mechanism in each traveling mode. It is a collinear diagram for explaining the operation state in HV-Hi mode. It is a collinear diagram for explaining the operation state in HV-Lo mode. It is a figure which shows an example of the map for defining each traveling mode. It is a map which shows the operating point with good thermal efficiency according to the operation mode of an engine. It is a flowchart for demonstrating the control example executed by the control apparatus in embodiment of this invention. It is a flowchart for demonstrating an example of switching control to HV-Lo mode corresponding to a low output mode. It is a flowchart for demonstrating an example of switching control to HV-Lo mode corresponding to a high output mode. It is a figure for demonstrating the change of the rotation speed of each rotation element when the control example shown in FIG. 8 is executed. It is a time chart for demonstrating the output torque of the engine, the 1st motor, the 2nd motor, and the engagement and disengagement state of each clutch mechanism when the control example shown in FIG. 8 is executed.

An example of a hybrid vehicle that can be a target in the embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a driving device 2 for driving the front wheels 1R and 1L. The drive device 2 is a so-called two-motor type drive device including an engine 3 and two motors 4 and 5 as driving force sources, and the first motor 4 is a motor having a power generation function (that is, a motor generator: MG1). ), The rotation speed of the engine 3 is controlled by the first motor 4, the second motor 5 is driven by the power generated by the first motor 4, and the drive torque output by the second motor 5 is calculated. It is configured to be applied to the drive torque transmitted from the engine 3 to the front wheels 1R and 1L. The second motor 5 can be configured by a motor having a power generation function (that is, a motor generator: MG2).

The engine 3 is an engine capable of setting operation modes having different output characteristics, such as an engine equipped with a conventionally known supercharger and an engine in which the number of operating cylinders can be changed. In other words, when a predetermined power is required to be output from the engine 3, the operating points where the thermal efficiency is good are the high output mode in which the low rotation speed and the high torque are obtained, and the high rotation speed. It is configured to be able to switch between a low output mode that produces low torque.

Explaining the high output mode and the low output mode with specific examples, if the engine 3 is equipped with a supercharger, the operation mode in which the supercharger is operated corresponds to the high output mode, and the supercharger is operated. The non-operating operation mode corresponds to the low output mode. Further, in the case of the engine 3 in which the number of operating cylinders can be changed, the operation mode (all cylinder operation) in which the air-fuel mixture is supplied to all cylinders and burned corresponds to the high output mode. For example, the operation mode in which the air-fuel mixture is supplied to half of the cylinders and burned (cylinder reduction operation) corresponds to the low output mode.

A power dividing mechanism 6 corresponding to the "differential mechanism" in the embodiment of the present invention is connected to the engine 3. The power splitting mechanism 6 includes a splitting unit 7 that mainly has a function of splitting the power output from the engine 3 into a first motor 4 side and an output side corresponding to the "motor" in the embodiment of the present invention. It is composed of a transmission unit 8 whose main function is to change the division ratio of the power.

The split portion 7 may have a configuration in which a differential action is performed by three rotating elements, and a planetary gear mechanism can be adopted. In the example shown in FIG. 1, it is configured by a single pinion type planetary gear mechanism. The division portion 7 shown in FIG. 1 includes a sun gear 9, a ring gear 10 which is an internal gear arranged concentrically with respect to the sun gear 9, and a sun gear 9 arranged between the sun gear 9 and the ring gear 10. It is composed of a pinion gear 11 that meshes with the ring gear 10 and a carrier 12 that holds the pinion gear 11 so that it can rotate and revolve. The sun gear 9 mainly functions as a reaction force element, the ring gear 10 mainly functions as an output element, and the carrier 12 mainly functions as an input element.

The power output from the engine 3 is input to the carrier 12. Specifically, the input shaft 14 of the power split mechanism 6 is connected to the output shaft 13 of the engine 3, and the input shaft 14 is connected to the carrier 12. Instead of the configuration in which the carrier 12 and the input shaft 14 are directly connected, the carrier 12 and the input shaft 14 may be connected via a transmission mechanism such as a gear mechanism. Further, a mechanism such as a damper mechanism or a torque converter may be arranged between the output shaft 13 and the input shaft 14.

The first motor 4 is connected to the sun gear 9. In the example shown in FIG. 1, the split portion 7 and the first motor 4 are arranged on the same axis as the rotation center axis of the engine 3, and the first motor 4 is on the opposite side of the split portion 7 from the engine 3. Have been placed. Between the division unit 7 and the engine 3, the transmission units 8 are arranged along the same axis as the division unit 7 and the engine 3 in the direction of the axis.

The transmission 8 is composed of a single pinion type planetary gear mechanism, and includes a sun gear 15, a ring gear 16 which is an internal gear arranged concentrically with respect to the sun gear 15, and the sun gear 15 and the ring gear 16. It has a pinion gear 17 that is arranged between the sun gears 15 and meshes with the ring gears 16 and a carrier 18 that holds the pinion gears 17 so as to rotate and revolve. The sun gear 15, the ring gear 16, and the carrier 18. It is a differential mechanism that performs a differential action by a rotating element. The ring gear 10 in the division 7 is connected to the sun gear 15 in the transmission 8. Further, the output gear 19 is connected to the ring gear 16 in the transmission unit 8.

The first clutch mechanism CL1 is provided so that the split portion 7 and the transmission portion 8 form a compound planetary gear mechanism. The first clutch mechanism CL1 is configured to selectively connect the carrier 18 in the transmission unit 8 to the carrier 12 in the division unit 7. The first clutch mechanism CL1 may be a friction type clutch mechanism such as a wet multi-plate clutch, or may be a meshing type clutch mechanism such as a dog clutch. By engaging the first clutch mechanism CL1, the carrier 12 in the split section 7 and the carrier 18 in the transmission section 8 are connected to form an input element, and the sun gear 9 in the split section 7 becomes a reaction force element. A compound planetary gear mechanism is formed in which the ring gear 16 in the transmission unit 8 is an output element.

Further, a second clutch mechanism CL2 for integrating the entire transmission unit 8 is provided. The second clutch mechanism CL2 is for connecting at least any two rotating elements such as connecting the carrier 18 and the ring gear 16 or the sun gear 15 in the transmission unit 8 or the sun gear 15 and the ring gear 16. It can be configured by a friction type or mesh type clutch mechanism. In the example shown in FIG. 1, the second clutch mechanism CL2 is configured to connect the carrier 18 and the ring gear 16 in the transmission unit 8. The first clutch mechanism CL1 and the second clutch mechanism CL2 are arranged on the same axis as the engine 3, the split portion 7, and the transmission portion 8, and are arranged on the opposite side of the division portion 7 with the shift portion 8 interposed therebetween. Has been done. As shown in FIG. 1, the clutch mechanisms CL1 and CL2 may be arranged side by side on the inner peripheral side and the outer peripheral side in the radial direction, or may be arranged side by side in the axial direction. May be good. When arranged side by side in the radial direction as shown in FIG. 1, the shaft length of the drive device 2 as a whole can be shortened. Further, when the clutch mechanisms are arranged side by side in the axial direction, the restrictions on the outer diameters of the clutch mechanisms CL1 and CL2 are reduced. Therefore, when the friction type clutch mechanism is adopted, the number of friction plates can be reduced. ..

The counter shaft 20 is arranged in parallel with the rotation center axis of the engine 3, the division portion 7, or the transmission portion 8. A driven gear 21 that meshes with the output gear 19 is attached to the counter shaft 20. Further, a drive gear 22 is attached to the counter shaft 20, and the drive gear 22 meshes with the ring gear 24 in the differential gear unit 23 which is the final reduction gear. Further, a drive gear 26 attached to the rotor shaft 25 of the second motor 5 meshes with the driven gear 21. Therefore, the power or torque output by the second motor 5 is added to the power or torque output from the output gear 19 at the driven gear 21 portion. The power or torque synthesized in this way is output from the differential gear unit 23 to the left and right drive shafts 27, and the power or torque is transmitted to the front wheels 1R and 1L.

A first power control device 28 having an inverter, a converter, and the like is connected to the first motor 4, and a second power control device 29 having an inverter, a converter, and the like is connected to the second motor 5, and each of these power control devices. 28 and 29 are connected to a power storage device 30 composed of a lithium ion battery, a capacitor, and the like. Further, the first power control device 28 and the second power control device 29 are configured to be able to supply electric power to each other. Specifically, when the first motor 4 functions as a generator as the reaction force torque is output, the electric power generated by the first motor 4 is not transmitted through the power storage device 30 to the second motor. It is configured so that it can be supplied to 5.

An electronic control unit (ECU) 31 for controlling the inverter, the converter, the engine 3, and the clutch mechanisms CL1 and CL2 in the power control devices 28 and 29 described above is provided. This ECU 31 is mainly composed of a microcomputer. FIG. 2 is a block diagram for explaining an example of the configuration of the ECU 31. In the example shown in FIG. 2, the ECU 31 is composed of the integrated ECU 32, the MG-ECU 33, the engine ECU 34, and the clutch ECU 35.

The integrated ECU 32 receives data from various sensors mounted on the vehicle, and based on the input data and a map, a calculation formula, etc. stored in advance, the MG-ECU33, the engine ECU34, and the clutch ECU35. It is configured to output a command signal to. An example of the data input to the integrated ECU 32 is shown in FIG. 2, which shows the vehicle speed, the accelerator opening, the rotation speed of the first motor (MG1) 4, the rotation speed of the second motor (MG2) 5, and the output shaft of the engine 3. 13 rotations (engine rotations), output rotations which are the rotations of the ring gear 16 or the counter shaft 20 in the transmission 8, stroke amount of each piston provided in each clutch mechanism CL1 and CL2, temperature of power storage device 30 , The temperature of each of the power control devices 28 and 29, the temperature of the first motor 4, the temperature of the second motor 5, the temperature of the oil (ATF) that lubricates the split section 7 and the transmission section 8, the remaining charge of the power storage device 30 Data such as (SOC) is input to the integrated ECU 32.

Then, the operating state (output torque and rotation speed) of the first motor 4 and the operating state (output torque and rotation speed) of the second motor 5 are obtained based on the data input to the integrated ECU 32, and these are obtained. The collected data is output to the MG-ECU33 as a command signal. Similarly, the operating state (output torque and rotation speed) of the engine 3 is obtained based on the data input to the integrated ECU 32, and the obtained data is output to the engine ECU 34 as a command signal. Further, the transmission torque capacities (including "0") of the clutch mechanisms CL1 and CL2 are obtained based on the data input to the integrated ECU 32, and the obtained data are output to the clutch ECU 35 as a command signal.

The MG-ECU 33 obtains a current value to be energized in each of the motors 4 and 5 based on the data input from the integrated ECU 32 as described above, and outputs a command signal to each of the motors 4 and 5. Since the motors 4 and 5 are AC motors, the above command signal includes the frequency of the current to be generated by the inverter, the voltage value to be boosted by the converter, and the like.

The engine ECU 34 uses the current for determining the opening degree of the electronic throttle valve based on the data input from the integrated ECU 32 as described above, the current for igniting the fuel in the ignition device, and the opening of the EGR (Exhaust Gas Recirculation) valve. The current for determining the degree, the current value for determining the opening degree of the intake valve and the exhaust valve, etc. are obtained, and a command signal is output to each valve or device. That is, the output (power) of the engine 3, the output torque of the engine 3, or an instruction signal for controlling the engine speed is output from the engine ECU 34. When the engine 3 is equipped with a supercharger, a signal for operating the supercharger is output from the engine ECU 34.

The clutch ECU 35 obtains a current value to be applied to the actuators that determine the engagement pressure of each clutch mechanism CL1 and CL2 based on the data input from the integrated ECU 32 as described above, and outputs a command signal to each actuator. ..

The above-mentioned drive device 2 can set an HV travel mode in which the drive travels by using the power generated by the engine 3. Further, in the HV traveling mode, when the first motor 4 is rotated at a low rotation speed (including "0" rotation), the engine 3 (or the input shaft 14) is more likely than the rotation speed of the ring gear 16 in the transmission unit 8. The HV-Lo mode in which the rotation speed is high, the HV-Hi mode in which the rotation speed of the engine 3 (or the input shaft 14) is lower than the rotation speed of the ring gear 16 in the transmission unit 8, and the transmission unit. It is possible to set a direct connection mode in which the rotation speed of the ring gear 16 in 8 and the rotation speed of the engine 3 (or the input shaft 14) are the same. In the HV-Lo mode and the HV-Hi mode, the engine speed changes by changing the speed of the first motor 4 during traveling. That is, the gear ratio, which is the ratio between the engine speed and the speed of the ring gear 16 (output speed), changes.

Each of these traveling modes is set by controlling the first clutch mechanism CL1 and the second clutch mechanism CL2. FIG. 3 shows these traveling modes and the engaged and disengaged states of the first clutch mechanism CL1 and the second clutch mechanism CL2 in each traveling mode as a chart. In the figure, the "○" symbol indicates the engaged state, and the "-" symbol indicates the released state.

The operation in the above-mentioned HV-Hi mode and HV-Lo mode will be described with reference to the collinear diagrams shown in FIGS. 4 and 5. The collinear diagram is a diagram in which straight lines showing each rotating element in the power dividing mechanism 6 are drawn in parallel with each other at intervals of gear ratios, and the distance from the baseline orthogonal to these straight lines is shown as the number of rotations of each rotating element. Is. Note that FIGS. 4 and 5 show a state in which the engine 3 is running at the same vehicle speed and at the same rotation speed.

When driving with the HV-Hi mode or HV-Lo mode set, the drive torque (positive torque) is output from the engine 3 as shown in FIGS. 4 and 5, and the first clutch mechanism CL1 and the second clutch mechanism CL2 By engaging any one of the above and outputting a reaction force torque for suppressing an increase in the engine rotation speed from the first motor 4, the torque corresponding to the drive torque output from the engine 3 is a power split mechanism. It is output from 6. The torque output from the power split mechanism 6 differs between the HV-Hi mode and the HV-Lo mode. In other words, the ratio of the torque transmitted to the ring gear 16 side in the power split mechanism 6 is different from the torque output from the engine 3.

Specifically, the ratio of the torque transmitted to the output gear 19 out of the torque output from the engine 3 is "1 / (1- (ρ1 × ρ2))" in the HV-Lo mode, which is HV-Hi. In the mode, it becomes "1 / (ρ1 + 1)". Here, "ρ1" is the gear ratio of the split portion 7 (the ratio of the number of teeth of the ring gear 10 to the number of teeth of the sun gear 9), and "ρ2" is the gear ratio of the transmission unit 8 (the number of teeth of the ring gear 16 and the sun gear). The ratio to the number of teeth of 15). The above ρ1 and ρ2 are set to values smaller than "1". Therefore, when the HV-Lo mode is set, the proportion of torque transmitted to the ring gear 16 is larger than when the HV-Hi mode is set.

On the contrary, the ratio of the torque transmitted to the first motor 4 out of the torque output from the engine 3 is "(ρ1 x ρ2) / (1- (ρ1 x ρ2))" in the HV-Lo mode. In the HV-Hi mode, it becomes "ρ1 / (ρ1 + 1)". That is, when a predetermined torque is output from the engine 3, the torque transmitted to the first motor 4 is larger in the HV-Hi mode than in the HV-Lo mode. Then, by outputting a torque balanced with the torque transmitted to the first motor 4 from the first motor 4, the rotation speed of each rotating element is maintained, and the above torque is transmitted to the output gear 19.

Here, when the rotation speed of the engine 3 is increased by the torque generated by the engine 3, the torque obtained by subtracting the torque required to increase the rotation speed of the engine 3 from the torque generated by the engine 3 is calculated. This is the torque output from the engine 3. That is, the torque substantially output from the output shaft 13 of the engine 3 becomes the torque output from the engine 3.

When the drive torque is output from the engine 3 and the reaction torque is output from the first motor 4 as described above, the target rotation speed of the engine 3 at which the operating point of the engine 3 is the operating point with good thermal efficiency is obtained. , The rotation speed of the first motor 4 is controlled so that the engine rotation speed becomes the target rotation speed. Therefore, the value obtained by dividing the target rotation speed of the engine 3 from the power required for the engine 3 is the output torque of the engine 3, and the output torque and the torque transmitted to the first motor 4 side by the power dividing mechanism 6. The reaction force torque is output from the first motor 4 according to the ratio of. The rotation speed of the first motor 4 can be continuously changed, and the engine rotation speed is determined based on the rotation speed of the first motor 4 and the vehicle speed. Therefore, the power split mechanism 6 functions as a continuously variable transmission.

The driving modes of the above-mentioned HV-Lo mode, HV-Hi mode, and direct connection mode are determined in principle based on the map shown in FIG. The horizontal axis in FIG. 6 is the vehicle speed, the vertical axis is the required driving force, and the region where the engine 3 is stopped and can be driven by the power of only the second motor 5 is hatched. As shown in FIG. 6, the HV-Lo mode is selected when the vehicle speed is relatively low or the required driving force is relatively large, and when the vehicle speed is relatively high and the required driving force is relatively small, the HV-Hi The mode is selected and the direct connection mode is selected when the driving state of the vehicle is the driving point (value based on the vehicle speed and the required driving force) between the areas where the HV-Lo mode and the HV-Hi mode are set. It is configured to.

Further, the above-mentioned HV-Lo mode, direct connection mode, and HV-Hi mode are configured to be switched by the operating point crossing each line shown in FIG. Specifically, when the operating point crosses the "Lo ← Fix" line in FIG. 6 from the right side to the left side, or when it crosses from the lower side to the upper side, the direct connection mode is changed to the HV-Lo mode. It is configured to switch, and when the driving point crosses the "Lo → Fix" line from the left side to the right side, or when it crosses from the upper side to the lower side, it switches from the HV-Lo mode to the direct connection mode. It is configured in. Similarly, when the operating point crosses the "Fix ← Hi" line in FIG. 6 from the right side to the left side, or when it crosses the line from the lower side to the upper side, the HV-Hi mode is switched to the direct connection mode. It is configured to switch from the direct connection mode to the HV-Hi mode when the driving point crosses the "Fix → Hi" line from the left side to the right side or from the upper side to the lower side. Has been done. Therefore, when switching from HV-Lo mode to HV-Hi mode, and conversely, when switching from HV-Hi mode to HV-Lo mode, the direct connection mode (fixed mode) is temporarily set in the switching process. In other words, switching between the HV-Lo mode and the HV-Hi mode is performed via the direct connection mode (fixed mode).

The vehicle speed V1 in FIG. 6 is set as the lower limit vehicle speed capable of passing through the direct connection mode. This means that if the operating point of the engine 3 drops from the area where the HV-Hi mode is set to the area where the vehicle speed is less than V1, switching to the HV-Lo mode via the direct connection mode can lead to engine stall. Because there is sex.

The area for setting the traveling mode shown in FIG. 6 and the line for switching between the HV-Hi mode and the HV-Lo mode are the temperature of each member constituting the drive device 2, the power storage device 30, or the electric power. It may be configured to fluctuate according to the temperature of the control devices 28 and 29, the remaining charge of the power storage device 30, and the like.

On the other hand, it is configured to switch the operation mode of the engine 3 according to the power required for the engine 3 and the like independently of the above-mentioned traveling mode. For example, when the power required for the engine 3 is equal to or higher than the predetermined power, the supercharger is operated or all cylinders are operated, and when the power required for the engine 3 is less than the predetermined power, the supercharger is supercharged. It is configured to stop the machine or perform a reduced cylinder operation. That is, the high output mode and the low output mode are switched according to the power required for the engine 3.

The operating point where the thermal efficiency is good when the high output mode is set is different from the operating point where the thermal efficiency is good when the low output mode is set. FIG. 7 is a diagram for explaining an operating point having good thermal efficiency according to each operation mode, and a solid line shows a line connecting the operating points with good thermal efficiency when the high output mode is set, and the output is low. The line connecting the operating points with good thermal efficiency when the mode is set is shown by the broken line. As shown in FIG. 7, the operating point of the engine 3 selected when a predetermined power is output from the engine 3 is a lower rotation speed in the high output mode than in the low output mode. In other words, when the engine 3 is operated at an operating point with good thermal efficiency, the output torque of the engine 3 at a predetermined rotation speed is larger in the high output mode than in the low output mode.

Therefore, for example, when the low output mode is set and the engine 3 is operating at the point A in FIG. 7, the required engine power is increased to a predetermined power P1 by depressing the accelerator pedal or the like. If the output mode is maintained, the operating point of the engine 3 is point B, and if the mode is switched to the high output mode, the operating point of the engine 3 is point C. Since the engine torque is a value obtained by dividing the engine power by the engine speed, the engine torque at point B, where the engine speed is high, is smaller than the engine torque at point C. Become.

As described above, the reaction force torque output from the first motor 4 is determined according to the engine torque. Therefore, the engine 3 is output from the first motor 4 when the engine 3 is operated at the point C rather than the point B in FIG. The reaction torque increases. Further, when the HV-Hi mode is set as described above, the ratio of the engine torque transmitted to the first motor 4 side is larger than that when the HV-Lo mode is set. Therefore, when the power required for the engine 3 increases and the operation mode of the engine 3 is switched to the high output mode while the HV-Hi mode is set, sufficient reaction torque is obtained from the first motor 4. Can not be output, the rotation speed of the engine 3 unintentionally increases, and sufficient drive torque may not be transmitted to the drive wheels 1R and 1L.

In the control device according to the embodiment of the present invention, the rotation speed of the engine 3 is unintentionally increased and the driving force is insufficient by performing the above-mentioned switching between the traveling mode and the operating mode of the engine 3 in a coordinated manner. It is configured to be able to suppress. An example of the control is shown in FIG. In the control example shown in FIG. 8, first, it is determined whether or not the engine 3 is in operation (step S1). This step S1 can be determined from whether or not there is a request to drive the engine 3 from various factors such as the magnitude of the required driving force, the vehicle speed, and the remaining charge of the power storage device 30.

If it is negatively determined in step S1 because the engine 3 is not in operation, that is, the power is output only from the second motor 5, the routine is temporarily terminated. On the contrary, when it is positively determined in step S1 that the engine 3 is in operation, the power Pe_req required for the engine 3 is calculated (step S2). Specifically, the required driving force is obtained from the accelerator opening degree and the vehicle speed based on a conventionally known driving force map (not shown), and the traveling power required for the vehicle is obtained from the required driving force and the vehicle speed. Further, the electric power to be generated by the first motor 4 is obtained from the remaining charge of the power storage device 30 and the like. Then, the sum of the obtained running power and the electric power is calculated as the required power Pe_req of the engine 3.

Then, the output rotation speed of the power split mechanism 6, that is, the rotation speed Nr of the ring gear 16 is calculated based on the vehicle speed (step S3), and directly connected from the HV-Hi mode based on the output rotation speed Nr of the power division mechanism 6. The switching rotation speed Ne_th of the engine 3 when switching to the mode is calculated (step S4).

Following step S4, the output power Pe_th1 of the engine 3 when the engine 3 is operated in the low output mode and rotated at the switching rotation speed Ne_th calculated in step S4 is obtained (step S5). This step S5 can be obtained from the switching rotation speed Ne_th and the map shown in FIG. 7.

Similarly, the output power Pe_th2 of the engine 3 when the engine 3 is operated in the high output mode and rotated at the switching rotation speed Ne_th calculated in step S4 is obtained (step S6). Similar to step S5, this step S6 can be obtained from the switching rotation speed Ne_th and the map shown in FIG. 7.

Then, it is determined whether or not the current vehicle speed V is equal to or higher than the fixed stage lower limit vehicle speed V1 (step S7). This is to prevent the engine speed from reaching the engine stall when switching from the HV-Hi mode to the HV-Lo mode as described later. The fixed stage lower limit vehicle speed V1 is the same vehicle speed as the vehicle speed V1 shown in FIG.

If the current vehicle speed V is less than the fixed step lower limit vehicle speed V1 and is negatively determined in step S7, the traveling mode cannot be switched, so this routine is temporarily terminated. On the contrary, if the current vehicle speed V is positively determined in step S7 because the vehicle speed V is equal to or higher than the fixed stage lower limit vehicle speed V1, it is determined whether or not the current driving mode is the HV-Hi mode ( Step S8). This step S7 can be determined by whether or not the traveling state determined from the required driving force and the vehicle speed is in the region where the HV-Hi mode of the map shown in FIG. 6 is set.

If it is negatively determined in step S8 because it is not in the HV-Hi mode, this routine is temporarily terminated as it is. On the contrary, when the HV-Hi mode is positively determined in step S8, the required power Pe_req of the engine 3 calculated in step S2 is the output power of the engine 3 calculated in step S5. It is determined whether or not it is less than Pe_th1 (step S9), and if it is positively determined that the required power Pe_req of the engine 3 is less than the output power Pe_th1 of the engine 3, the engine 3 is operated in the low output mode. The operating point of the engine 3 in this case, that is, the target engine power Pe_tag and the target engine rotation speed Ne_tag are set (step S10). Specifically, the target engine power Pe_tag is set to the same value as the required power Pe_req calculated in step S2, and the engine rotation obtained from the target engine power Pe_tag and the optimum fuel consumption line in the low output mode shown in FIG. Set the number as the target engine speed Ne_tag.

Then, while maintaining the state in which the HV-Hi mode is set (step S11), it is determined whether or not the current engine speed Ne is less than the target engine speed Ne_tag (step S12). If the current engine speed Ne is less than the target engine speed Ne_tag and is positively determined in step S12, the engine speed Ne is increased toward the target speed Ne_tag and the engine power Pe is targeted. It is increased toward the engine power Pe_tag (step S13) and returns to step S12. On the contrary, if the current engine speed Ne is equal to or higher than the target engine speed Ne_tag (specifically, Ne = Ne_tag) and is negatively determined in step S12, this routine is temporarily terminated. To do.

On the other hand, if the required power Pe_req of the engine 3 is positively determined in step S9 because the output power Pe_req of the engine 3 is equal to or higher than the output power Pe_th1 of the engine 3, the required power Pe_req of the engine 3 of the engine 3 calculated in step S6 It is determined whether or not the output power is less than Pe_th2 (step S14). If the required power Pe_req of the engine 3 is less than the output power Pe_th2 of the engine 3 and is positively determined in step S14, the operating point of the engine 3 when the engine 3 is operated in the low output mode, that is, the target The engine power Pe_tag and the target engine speed Ne_tag are set (step S15). This step S15 is the same as the above step S10.

Then, it is determined whether or not the current engine speed Ne is less than the switching speed Ne_th calculated in step S4 (step S16). That is, it is determined whether or not it is the timing at which the driving mode cannot be switched from the HV-Hi mode to the HV-Lo mode via the direct connection mode. Therefore, if the current engine speed Ne is less than the switching speed Ne_th and is positively determined in step S16, the engine speed Ne is increased while maintaining the HV-Hi mode (step S17). At the same time, the engine power Pe is increased (step S18), and the engine returns to step S16. On the contrary, when the current engine speed Ne is negatively determined in step S16 because it is equal to or higher than the switching speed Ne_th (specifically, Ne = Ne_th), it is based on the flowchart shown in FIG. The driving mode is switched from the HV-Hi mode to the HV-Lo mode (step S19).

Here, a control example for switching from the HV-Hi mode shown in FIG. 9 to the HV-Lo mode will be described. In the control example shown in FIG. 9, first, it is determined whether or not the difference rotation speed Nd of the first clutch mechanism CL1 is equal to or less than the target difference rotation speed Nd_tag (step S191). The difference rotation speed Nd of the first clutch mechanism CL1 in step S191 is the difference in rotation speed between the carrier 12 and the carrier 18 to be engaged, and the target difference rotation speed Nd_tag is the first clutch mechanism CL1. It is determined based on a predetermined rotation speed difference so that a shock does not occur at the time of engagement, or, if the first clutch mechanism CL1 is a friction type clutch mechanism, the amount of heat generated by slipping. The difference in rotation speed, or if the first clutch mechanism CL1 is a meshing type clutch mechanism, the difference in rotation speed is determined based on the durability of the meshing teeth, the speed at which the meshing teeth are stroked, and the like. The difference rotation speed Nd of the first clutch mechanism CL1 may be calculated based on the data provided by providing a sensor that directly detects the rotation speed difference between the carrier 12 and the carrier 18, and the engine 3 and the first motor 4. It may be calculated from the vehicle speed V and the like.

If the difference rotation speed Nd of the first clutch mechanism CL1 is larger than the target difference rotation speed Nd_tag and is negatively determined in step S191, the difference rotation speed Nd of the first clutch mechanism CL1 is less than the target difference rotation speed Nd_tag. Step S191 is repeatedly executed until On the contrary, when the difference rotation speed Nd of the first clutch mechanism CL1 is less than the target difference rotation speed Nd_tag and it is positively determined in step S191, the first clutch mechanism CL1 is engaged (step). S192), the torque of the first motor 4 is reversed (step S193), and the second clutch mechanism CL2 is further released (step S194). Specifically, the torque of the first motor 4 is maintained so that the torque transmitted from the engine 3 to the first motor 4 and the reaction force torque of the first motor 4 are balanced, and the first clutch mechanism CL1 is operated in that state. Engage. After that, the reaction force torque of the first motor 4 is reduced, and the direction of the torque of the first motor 4 is reversed. Then, the second clutch mechanism CL2 is released while maintaining a state in which the inverted torque of the first motor 4 and the torque transmitted from the engine 3 to the first motor 4 are in equilibrium.

After switching based on the control example shown in FIG. 9, the share of torque transmitted to the first motor 4 and the rotation speed of the first motor 4 for controlling the rotation speed of the engine 3 are HV-Hi. Since it is different from the mode, the traveling mode is set to the HV-Lo mode after step S27 (step S20). Then, it is determined whether or not the current engine speed Ne is less than the target engine speed Ne_tag set in step S15 (step S21). If the current engine speed Ne is less than the target engine speed Ne_tag and is positively determined in step S21, the engine speed Ne is increased toward the target speed Ne_tag and the engine power Pe is targeted. It is increased toward the engine power Pe_tag (step S22) and returns to step S21. On the contrary, if the current engine speed Ne is equal to or higher than the target engine speed Ne_tag (specifically, Ne = Ne_tag) and is negatively determined in step S21, this routine is temporarily terminated. To do.

If the required power Pe_req of the engine 3 is negatively determined in step S14 because it is equal to or higher than the output power Pe_th2 of the engine 3, the operating point of the engine 3 when the engine 3 is operated in the high output mode, That is, the target engine power Pe_tag and the target engine rotation speed Ne_tag are set (step S23). Specifically, the target engine power Pe_tag is set to the same value as the required power Pe_req calculated in step S2, and the engine rotation obtained from the target engine power Pe_tag and the optimum fuel consumption line in the high output mode shown in FIG. Set the number as the target engine speed Ne_tag.

Then, similarly to the above step S16, it is determined whether or not the current engine speed Ne is less than the switching speed Ne_th calculated in step S4 (step S24), and the current engine speed Ne is switched. If it is positively determined in step S24 because the engine speed is less than Ne_th, the engine speed Ne is increased and the engine power Pe is increased while maintaining the HV-Hi mode (step S25). S26), return to step S24. The operation mode of the engine 3 is maintained in the low output mode until a negative determination is made in step S24. On the contrary, when the current engine speed Ne is negatively determined in step S24 because it is equal to or higher than the switching speed Ne_th (specifically, Ne = Ne_th), it is based on the flowchart shown in FIG. The driving mode is switched from the HV-Hi mode to the HV-Lo mode (step S27).

Here, a control example for switching from the HV-Hi mode shown in FIG. 10 to the HV-Lo mode will be described. In the control example shown in FIG. 10, first, as in step S191 in the control example shown in FIG. 9, it is determined whether or not the difference rotation speed Nd of the first clutch mechanism CL1 is equal to or less than the target difference rotation speed Nd_tag (step). S271).

If the difference rotation speed Nd of the first clutch mechanism CL1 is larger than the target difference rotation speed Nd_tag and is negatively determined in step S271, the difference rotation speed Nd of the first clutch mechanism CL1 is less than the target difference rotation speed Nd_tag. Step S271 is repeatedly executed until On the contrary, when it is positively determined in step S271 that the difference rotation speed Nd of the first clutch mechanism CL1 is less than the target difference rotation speed Nd_tag, the first step is the same as in step S192 and step S193. The clutch mechanism CL1 is engaged (step S272), and the torque of the first motor 4 is reversed (step S273).

On the other hand, in the control example shown in FIG. 10, the driving mode is switched and the operation mode of the engine 3 is switched. Following step S273, the operation mode of the engine 3 is changed from the low output mode to the high output mode. (Step S274), and then the second clutch mechanism CL2 is released in the same manner as in step S194 (step S275).

In this case, while the reaction torque of the first motor 4 is being reduced and reversed, the operation mode of the engine 3 is switched and the output torque of the engine 3 is increased. Since the response time from the input of the command signal to the change in torque of the first motor 4 is faster than the response time until the output torque of the engine 3 is increased by switching the operation mode of the engine 3, the engine The command signal for switching the operation mode of 3 may be output before the command signal for reducing or reversing the torque of the first motor 4. That is, in the example shown in FIG. 10, it is sufficient that the reaction torque of the first motor 4 starts to decrease before the output torque of the engine 3 starts to increase.

After switching based on the control example shown in FIG. 10, the share of torque transmitted to the first motor 4 and the rotation speed of the first motor 4 for controlling the rotation speed of the engine 3 are HV-Hi. Since it is different from the mode, the traveling mode is set to the HV-Lo mode after step S27 (step S28). Then, it is determined whether or not the current engine speed Ne is less than the target engine speed Ne_tag set in step S23 (step S29). If it is positively determined in step S29 that the current engine speed Ne is less than the target engine speed Ne_tag, the engine speed Ne is increased toward the target speed Ne_tag and the engine power Pe is targeted. The engine power is increased toward Pe_tag (step S30) and returns to step S29. On the contrary, if the current engine speed Ne is equal to or higher than the target engine speed Ne_tag (specifically, Ne = Ne_tag) and is negatively determined in step S29, this routine is temporarily terminated. To do.

The rotation speed of each rotating element constituting the power dividing mechanism 6 when the traveling mode and the operating mode of the engine 3 are switched based on the control example described above, and the output of the engine 3, the first motor 4, and the second motor 5. 11 and 12 are diagrams for explaining the torque and the changes in the clutch mechanisms CL1 and CL2.

In the example shown here, at the time of t0, the first clutch mechanism CL1 is released and the second clutch mechanism CL2 is engaged because the HV-Hi mode is set. Further, since the traveling power required for the vehicle is relatively small, the operation mode of the engine 3 is a low output mode, and the output torque is low. Therefore, the reaction force torque by the first motor 4 is also set to a small value. For convenience, it is assumed that the drive torque is not output from the second motor 5.

In that state, the engine speed gradually increases, and as shown in FIG. 11B, the difference speed between the carrier 18 and the ring gear 16 decreases, so that the first clutch mechanism CL1 starts to engage at t1. At t2, the first clutch mechanism CL1 is completely engaged. The state is shown in FIG. 11 (c).

On the other hand, the torque of the first motor 4 is maintained until the time t3. That is, the torque of the first motor 4 is controlled so that the torque transmitted from the engine 3 to the first motor 4 and the torque of the first motor 4 are balanced. Therefore, from the time t2 to the time t3, substantially all of the reaction torque is taken care of by the first motor 4. Then, at the time of t3, the torque handled by the first clutch mechanism CL1 is increased by reducing the reaction force torque. Further, at the time of t3, the output torque of the second motor 5 is increased in order to increase the drive torque (output torque of the power split mechanism 6), and the drive torque is increased accordingly.

A signal for switching the operation mode of the engine 3 is output before and after the time t3, and the engine torque starts to increase at the time t4. Therefore, the torque of the second motor 5, which has been increased from the time t3 in accordance with the increase in the engine torque, is gradually decreasing. Further, the torque of the first motor 4 is reduced from the time t3, the direction of the torque is reversed at the time t5, and the torque gradually increases to a torque corresponding to the engine torque increased at the time t6. There is.

As described above, the torque of the first motor 4 is increased, and the torque transmitted from the engine 3 to the first motor 4 is balanced with the torque of the first motor 4, so that the torque handled by the second clutch mechanism CL2 is almost equal. When it becomes "0", the second clutch mechanism CL2 starts to be released at t7, and the second clutch mechanism CL2 is completely released at t8. FIG. 11D shows a state in which the second clutch mechanism CL2 is released.

Then, since the HV-Lo mode is set by releasing the second clutch mechanism CL2 as described above, the first motor 4 is set so that the engine speed becomes the target speed as shown in FIG. 11 (e). The number of revolutions of is reduced.

By selecting and setting the driving mode and the operating mode of the engine 3 according to the required power of the engine 3 as described above, the driving mode is set to the HV-Lo mode when the operating mode of the engine 3 is switched to the high output mode. Therefore, it is possible to prevent a situation in which the reaction torque of the first motor 4 is insufficient and the engine speed is excessively increased or the driving force is insufficient.

Further, as shown in FIG. 11, since the running mode and the operation mode of the engine 3 can be switched while increasing the engine speed, the increase in the required power and the change in the behavior of the engine speed expected or predicted by the driver It can be matched with the method, in other words, it is possible to suppress the decrease in the engine speed while the required power increases, and it is possible to suppress the driver from feeling uncomfortable.

Further, by executing the control of reducing the reaction force torque of the first motor 4 and reversing the direction of the torque in order to switch the traveling mode and the control of switching the operation mode of the engine 3 at the same time, a short time is obtained. Since the driving mode and the driving mode can be switched with, it is possible to suppress the engine speed from stagnation and to prevent the driver from feeling uncomfortable. Further, in consideration of the response delay until the engine torque increases due to the switching of the operation mode of the engine 3, the torque is output from the second motor 5, in other words, at the same time as the reaction torque of the first motor 4 decreases. By outputting the driving torque from the second motor 5, the driving force can be increased quickly and continuously.

The hybrid vehicle according to the embodiment of the present invention is not limited to the configuration shown in FIG. 1, and can switch at least two traveling modes in which the engine torque is transmitted to the drive wheels by the first motor 4 taking charge of the reaction torque. However, it may be a hybrid vehicle in which the magnitude of the reaction force torque handled by the first motor 4 differs depending on the traveling modes. If the configuration of such a hybrid vehicle is conceptually shown, "the engine, the motor (first motor), the first rotating element in which any one of the drive wheels is connected, and the engine , The first differential mechanism having the motor, the second rotating element to which the other one of the driving wheels is connected, and the third rotating element, the engine, the motor, and the driving wheels. A second differential mechanism having a fourth rotating element to which the other one is connected, a fifth rotating element connected to the third rotating element, and a sixth rotating element, and the first At least one of a first engaging mechanism that selectively connects the rotating element or the second rotating element and the sixth rotating element, the fourth rotating element, the fifth rotating element, and the sixth rotating element. It is a hybrid vehicle equipped with a second engaging mechanism that selectively connects two rotating elements. "

1R, 1L ... front wheels (driving wheels), 2 ... driving device, 3 ... engine, 4, 5 ... motor, 6 ... power split mechanism, 7 ... split section, 8 ... transmission section, 9, 15 ... sun gear, 10, 16 ... Ring gear, 12, 18 ... Carrier, 30 ... Power storage device, 31 ... Electronic control unit (ECU), CL1, CL2 ... Clutch mechanism.

Claims (2)

A differential having at least three rotating elements of an engine, a motor, a first rotating element to which the engine is connected, a second rotating element to which the motor is connected, and a third rotating element to which the drive wheels are connected. Equipped with a mechanism
The engine has at least two operations, a high output mode in which the output torque at a predetermined rotation speed is relatively large and a low output mode in which the output torque is relatively small when the engine is operated at an operating point with good thermal efficiency. It is configured to switch modes,
In the differential mechanism, the torque transmitted from the first rotating element to the third rotating element is relatively large in the Lo mode, and the torque transmitted from the first rotating element to the third rotating element is relative to each other. In a hybrid vehicle control device that is configured to be able to set at least two driving modes with a small Hi mode.
A controller for controlling the operation mode and the driving mode is provided.
The controller
When the required power to the hybrid vehicle is equal to or less than the first predetermined power when traveling with the Hi mode set, the low output mode is set and the Hi mode is maintained, and the required power is the first predetermined power or less. When the second predetermined power is larger than the first predetermined power, the high output mode is set and the traveling mode is switched from the Hi mode to the Lo mode, and the required power is larger than the first predetermined power and the said. A control device for a hybrid vehicle, characterized in that when the power is less than the second predetermined power, the low output mode is set and the traveling mode is switched from the Hi mode to the Lo mode.
In the hybrid vehicle control device according to claim 1,
The differential mechanism is configured so that a fixed stage mode in which the rotation speed ratio between the first rotating element and the third rotating element is a fixed ratio can be further set, and the Hi mode is passed through the fixed stage mode. The Lo mode is set with respect to the direction of the reaction force torque output by the motor when the Hi mode is set to switch the Lo mode and the torque is transmitted from the engine to the drive wheels. It is configured so that the direction of the reaction force torque output by the motor is reversed when the torque is transmitted from the engine to the drive wheels by setting.
The controller
When the Lo mode and the high output mode are set from the state in which the Hi mode and the low output mode are set, the reaction force torque due to the torque of the motor is obtained when the Hi mode is switched to the fixed stage mode. Control of a hybrid vehicle, characterized in that reverse control for reducing the magnitude of the motor and reversing the direction of torque of the motor and control for switching the output mode of the engine are executed in an overlapping manner. apparatus.

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