JP2021000925A - Hybrid vehicle and method for controlling hybrid vehicle - Google Patents

Abstract

To quickly secure a desired driving force in returning from engine stop control.SOLUTION: A vehicle 100 includes an engine 3, a CVT 13 to which power is transmitted from the engine 3, a forward clutch 12b and a retreat brake 12c that disconnect a power transmission path connecting the engine 3 and the CVT 13, and an MG 4 connected to the shaft of a primary pully 13a of the CVT 13. When being returned from sailing stop control that is one example of engine stop control, the vehicle 100 includes a controller 20 for outputting a torque by the MG 4.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hybrid vehicle and a method for controlling a hybrid vehicle.

Patent Document 1 discloses a technique for performing sailing stop control for releasing a clutch that engages and disengages a power transmission path connecting an engine and a continuously variable transmission mechanism during traveling to stop the engine. In the technique of Patent Document 1, the gear ratio of the continuously variable transmission mechanism is set to the minimum gear ratio by performing gear shift control according to the coast line of the gear shift map during sailing stop control.

International Publication No. 2017/051678

When returning from engine stop control such as sailing stop control, in addition to starting the engine, synchronizing the rotation of the clutch, and engaging the clutch, a series of controls such as shift control of the continuously variable transmission mechanism to the low side, that is, the side with a small gear ratio, are performed. May be done. Therefore, when returning from the engine stop control, it takes time for the final shift to the low side, and as a result, a time lag may occur until a desired driving force is obtained.

The present invention has been made in view of such a problem, and an object of the present invention is to quickly secure a desired driving force when returning from engine stop control.

A hybrid vehicle according to an embodiment of the present invention comprises an engine, a stepless speed change mechanism for transmitting power from the engine, a clutch for connecting and disconnecting a power transmission path connecting the engine and the stepless speed change mechanism, and the clutch. Is a hybrid vehicle including a motor connected to a power transmission path on the drive wheel side, and includes a control unit that outputs torque by the motor when returning from engine stop control.

According to another aspect of the present invention, a hybrid vehicle control method corresponding to the hybrid vehicle of the above aspect is provided.

According to these aspects, by outputting the torque by the motor when returning from the engine stop control, it is possible to secure the driving torque while the engine rotation is increasing until the clutch engagement is completed. Therefore, according to these aspects, a desired driving force can be quickly secured when returning from the engine stop control.

It is a schematic block diagram of a hybrid vehicle. It is a figure which shows an example of a shift map. It is a figure which shows an example of the control concerning embodiment by the flowchart. It is a figure which shows an example of the timing chart corresponding to the control concerning embodiment.

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

(First Embodiment)
FIG. 1 is a schematic configuration diagram of a hybrid vehicle 100 (hereinafter, referred to as “vehicle 100”) according to an embodiment of the present invention. The vehicle 100 includes a low-voltage battery 1 as a first battery, a high-voltage battery 2 as a second battery, an engine 3 as a driving drive source, a motor generator 4 (hereinafter referred to as "MG4"), and an engine. The starter motor 5 (hereinafter referred to as "SM5") as the first rotary electric machine used for starting the engine 3 and the starter generator 6 (hereinafter referred to as "SM5") as the second rotary electric machine used for power generation, assisting and starting the engine 3. (Referred to as "SG6"), a DC-DC converter 7, an inverter 8, a mechanical oil pump 9 and an electric oil pump 10 as hydraulic sources, a torque converter 11 constituting a transmission, a forward / backward switching mechanism 12, and a forward / backward switching mechanism 12. It includes a stepless speed change mechanism 13 (hereinafter, referred to as “CVT 13”), a differential mechanism 14, a drive wheel 18, and a controller 20.

The low voltage battery 1 is a lead acid battery having an output voltage of DC12V. The low-voltage battery 1 is connected to the low-voltage circuit 16 together with electrical components 15 (automatic driving camera 15a and sensor 15b, navigation system 15c, audio 15d, air conditioner blower 15e, etc.) that operate at SM5 and 12V. The low voltage battery 1 may be a lithium ion battery having an output voltage of 12 V.

The high-voltage battery 2 is a DC48V lithium-ion battery having a higher output voltage than the low-voltage battery 1. The output voltage of the high voltage battery 2 may be lower or higher than this, for example, 30V or 100V. The high-voltage battery 2 is connected to the high-voltage circuit 17 together with the MG4, SG6, inverter 8, electric oil pump 10, and the like.

The low-voltage circuit 16 and the high-voltage circuit 17 are connected via a DC-DC converter 7. The DC-DC converter 7 has a boosting function that boosts 12V of the low voltage circuit 16 to 48V and outputs 48V to the high voltage circuit 17, and steps down 48V of the high voltage circuit 17 to 12V to supply 12V to the low voltage circuit 16. It has a step-down function to output. As a result, the DC-DC converter 7 can output a voltage of 12 V to the low voltage circuit 16 regardless of whether the engine 3 is running or stopped. When the remaining capacity of the high-voltage battery 2 is low, the 12V of the low-voltage circuit 16 can be boosted to 48V and output to the high-voltage circuit 17 to charge the high-voltage battery 2.

The engine 3 is an internal combustion engine that uses gasoline, light oil, or the like as fuel, and its rotational speed, torque, or the like is controlled based on a command from the controller 20.

The torque converter 11 is provided on the power transmission path between the engine 3 and the forward / backward switching mechanism 12, and transmits power via a fluid. Further, the torque converter 11 can improve the power transmission efficiency of the driving force from the engine 3 by engaging the lockup clutch 11a when the vehicle 100 is traveling at a predetermined lockup vehicle speed or higher.

The forward / backward switching mechanism 12 is provided on the power transmission path between the torque converter 11 and the CVT 13, and includes a planetary gear mechanism 12a, a forward clutch 12b, and a reverse brake 12c. When the forward clutch 12b is engaged and the reverse brake 12c is released, the rotation of the engine 3 input to the forward / backward switching mechanism 12 via the torque converter 11 is transferred from the forward / backward switching mechanism 12 to the CVT 13 while maintaining the rotation direction. It is output. On the contrary, when the forward clutch 12b is released and the reverse brake 12c is engaged, the rotation of the engine 3 input to the forward / backward switching mechanism 12 via the torque converter 11 is decelerated and the rotation direction is reversed to switch forward / backward. It is output from the mechanism 12 to the CVT 13. The flood control required by the forward / backward switching mechanism 12 is generated by a hydraulic circuit (not shown) using the flood pressure generated by the mechanical oil pump 9 or the electric oil pump 10 as the original pressure.

The CVT 13 is arranged on the power transmission path between the forward / backward switching mechanism 12 and the differential mechanism 14, and changes the gear ratio steplessly according to the vehicle speed, the accelerator opening degree which is the operation amount of the accelerator pedal, and the like. The CVT 13 includes a primary pulley 13a, a secondary pulley 13b, and a belt 13c wound around both pulleys. In the CVT 13, the gear ratio can be changed steplessly by changing the groove widths of the primary pulley 13a and the secondary pulley 13b by flood control and changing the contact radius between the pulleys 13a and 13b and the belt 13c. The flood pressure required by the CVT 13 is generated by a hydraulic circuit (not shown) using the flood pressure generated by the mechanical oil pump 9 or the electric oil pump 10 as the original pressure.

The MG4 is a synchronous rotary electric machine in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. The MG4 is connected to the shaft of the primary pulley 13a via a chain 21 wound between the sprocket provided on the shaft of the MG4 and the sprocket provided on the shaft of the primary pulley 13a.

The MG 4 is branched and connected to the power transmission path connecting the engine 3 and the drive wheels 18 on the engine 3 side of the secondary pulley 13b. Further, the MG 4 is branched and connected to the power transmission path on the drive wheel 18 side of the forward / backward switching mechanism 12 including the clutch provided between the engine 3 and the primary pulley 13a of the power transmission path. Connecting the belt 13c to the shaft of the primary pulley 13a from the side opposite to the engine 3 with the belt 13c in between is included in the branch connection to the power transmission path.

The shaft of the primary pulley 13a to which the MG4 is connected constitutes a power transmission path on the drive wheel 18 side of the forward clutch 12b and the reverse brake 12c that form a clutch that connects and disconnects the power transmission path connecting the engine 3 and the CVT 13. The MG 4 may be connected to, for example, a power transmission path connecting the forward / backward switching mechanism 12 and the CVT 13, or may be connected to a power transmission path connecting the CVT 13 and the differential mechanism 14.

The MG 4 is controlled by applying a three-phase alternating current generated by the inverter 8 based on a command from the controller 20. The MG 4 operates as an electric motor that is rotationally driven by receiving electric power supplied from the high-voltage battery 2. Further, the MG 4 functions as a generator that generates an electromotive force at both ends of the stator coil when the rotor receives rotational energy from the engine 3 and the drive wheels 18, and can charge the high voltage battery 2.

The sprocket provided on the shaft of the MG4 and the sprocket provided on the shaft of the primary pulley 13a are configured so that the latter has a large number of teeth (for example, the number of teeth = 1: 3), and the output rotation of the MG3 is decelerated. Is transmitted to the primary pulley 13a. As a result, the torque required for the MG4 is reduced, the MG4 is miniaturized, and the degree of freedom in arranging the MG4 is improved. Together with these sprockets, the chain 21 constitutes a deceleration mechanism DM that decelerates the output rotation of the MG 4 and transmits it to the shaft of the primary pulley 13a. A gear train may be used instead of the chain 21.

The SM5 is a DC motor, and is arranged so that the pinion gear 5a can be meshed with the outer peripheral gear 3b of the flywheel 3a of the engine 3. When the engine 3 is started from a cold state for the first time (hereinafter referred to as "first start"), power is supplied from the low voltage battery 1 to the SM5, the pinion gear 5a is meshed with the outer gear 3b, the flywheel 3a, and further. The crankshaft is rotated. Since the low-voltage battery 1 is a lead-acid battery, the SM5 is used when the engine 3 is started for the first time, so that power can be stably supplied from the low-voltage battery 1 to the SM5 even at extremely low temperatures. This is because the SM5 can generate the torque and output required to start the engine 3 for the first time.

The torque and output required to start the engine 3 are the largest at the first start, and are smaller at the start from the warm-up state, that is, at the restart than at the first start. This is because the temperature of the engine oil is low and the viscosity of the engine oil is high at the first start, whereas the temperature of the engine oil rises and the viscosity of the engine oil decreases after the first start.

The SG6 is a synchronous rotary electric machine, which is connected to the crankshaft of the engine 3 via a V-belt 22 and functions as a generator when receiving rotational energy from the engine 3. The electric power generated in this way is charged into the high voltage battery 2 through the inverter 8. Further, the SG 6 operates as an electric motor that is rotationally driven by receiving electric power supplied from the high-voltage battery 2, and assists the driving force of the engine 3. Further, the SG6 is used to rotationally drive the crankshaft of the engine 3 to restart the engine 3 when the engine 3 is restarted from the idling stop state.

The mechanical oil pump 9 is an oil pump that operates by transmitting the rotation of the engine 3 via the chain 23. The mechanical oil pump 9 sucks up the hydraulic oil stored in the oil pan and supplies the oil to the lockup clutch 11a, the forward / backward switching mechanism 12 and the CVT 13 via a hydraulic circuit (not shown).

The electric oil pump 10 is an oil pump operated by electric power supplied from the high voltage battery 2. The electric oil pump 10 operates when the engine 3 is stopped and the mechanical oil pump 9 cannot be driven by the engine 3, such as in EV mode or idle stop state, and is stored in the oil pan in the same manner as the mechanical oil pump 9. The oil is sucked up and supplied to the lockup clutch 11a, the forward / backward switching mechanism 12 and the CVT 13 via a hydraulic circuit (not shown). In particular, by securing the necessary flood pressure in the CVT 13, the slip of the belt 13c is suppressed.

The controller 20 is composed of one or a plurality of microcomputers including a central arithmetic unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 20 corresponds to the control unit, and by executing the program stored in the ROM or RAM by the CPU, the engine 3, the inverter 8 (MG4, SG6, the electric oil pump 10), the DC-DC converter 7, the SM5, The lockup clutch 11a, the forward / backward switching mechanism 12, the CVT 13, and the like are controlled in an integrated manner.

As the operation mode of the vehicle 100, the controller 20 drives the MG4 with the electric power supplied from the high-voltage battery 2 and travels by the driving force of the MG4 only, and the engine traveling mode of traveling by the driving force of the engine 3 only. And the HEV mode in which the vehicle travels according to the driving force of the engine 3 and the driving force of the MG 4.

In the EV mode, the vehicle 100 travels by driving only the MG4 with the electric power from the high-voltage battery 2 in a state where the forward clutch 12b and the reverse brake 12c are released (hereinafter, this state is referred to as "EV travel"). .. The EV mode is selected when the required output of the vehicle 100 is low and the remaining capacity of the high voltage battery 2 is sufficient.

In the engine running mode, the vehicle 100 runs by driving only the engine 3 with either the forward clutch 12b or the reverse brake 12c engaged. The engine running mode is selected when the required output of the vehicle 100 is relatively high.

In the HEV mode, the vehicle 100 runs by driving the engine 3 and the MG 4 with either the forward clutch 12b or the reverse brake 12c engaged. The HEV mode is selected when the required output of the vehicle 100 is high, specifically, when the required output of the vehicle 100 cannot be supplemented only by the output of the engine 3.

The controller 20 selects a driving mode based on the accelerator opening, the pedal effort of the brake pedal, and the vehicle speed in consideration of a driving mode selection map (not shown), and sets the engines 3 and MG 4 so that the selected driving mode is realized. Drive.

By the way, in the vehicle 100, sailing stop control, which is an example of engine stop control, is performed. In the sailing stop control, when the sailing stop condition is satisfied, the forward clutch 12b and the reverse brake 12c are released to stop the engine 3. That is, in the sailing stop control, when the sailing stop condition is satisfied, the transmission is set to the neutral state and the engine 3 is stopped. According to such sailing stop control, the fuel consumption of the engine 3 can be improved by stopping the engine 3 and extending the coasting mileage.

The sailing stop condition includes that the vehicle speed is higher than the set vehicle speed VSP3, that the accelerator pedal is not depressed, that the brake pedal is not depressed, and that the forward range is selected by the transmission. The set vehicle speed VSP3 is set so as to distinguish between low speed and medium high speed, and can be set in advance by experiments or the like.

During sailing stop control, for example, shift control can be performed according to the coast line C of the shift map described below.

FIG. 2 is a diagram showing an example of a shift map. The CVT 13 is shifted based on the shift map. Specifically, a shift line is set for each accelerator opening in the shift map, and the shift of the CVT 13 is performed according to the shift line selected according to the accelerator opening. In FIG. 3, a coast line C is illustrated as a shift line.

In the shift map, the operating point of the CVT 13 is shown according to the vehicle speed and the rotation speed of the primary pulley 13a. In the shift map, the gear ratio is indicated by the slope of the line connecting the operating point and the zero point of the shift map. Therefore, the shift line indicates the setting of the gear ratio according to the vehicle speed.

The shifting of the CVT 13 can be performed between the highest line obtained by minimizing the gear ratio and the lowest line obtained by maximizing the gear ratio. The coast line C is set to the highest line when the vehicle speed is a predetermined vehicle speed VSP1 or higher, and in this case, the gear ratio becomes the minimum gear ratio. The predetermined vehicle speed VSP1 is the minimum value of the vehicle speed corresponding to the highest line on the coast line C.

The coast line C is set to the lowest line when the vehicle speed is the predetermined vehicle speed VSP2 or less, and in this case, the gear ratio Ratio becomes the maximum gear ratio. The predetermined vehicle speed VSP2 is the maximum value of the vehicle speed corresponding to the lowest line on the coast line C.

The set vehicle speed VSP3 is set lower than the predetermined vehicle speed VSP1 and higher than the predetermined vehicle speed VSP2. Therefore, when shifting is performed according to the coast line C during sailing stop control, the gear ratio of the CVT 13 is set to the minimum gear ratio while the vehicle speed is higher than the predetermined vehicle speed VSP1.

On the other hand, when returning from sailing stop control, a series of controls such as starting the engine 3, synchronizing the rotation of the forward clutch 12b, engaging the forward clutch 12b, and controlling the shift of the CVT 13 to the low side, that is, the side with a small gear ratio are performed. It is said. Therefore, as a result of the time required for the final shift to the low side, there is a concern that a time lag may occur until a desired driving force is obtained.

In particular, if the gear ratio of the CVT 13 is set to the minimum gear ratio during sailing stop control, there is a concern that a time lag may occur as a result of the time required for the final shift to the low side when returning from sailing stop control. ..

In view of such circumstances, in the present embodiment, the controller 20 executes the control described below.

FIG. 3 is a flowchart showing an example of control performed by the controller 20. The controller 20 is configured to have a control unit by being configured to execute the processing of this flowchart.

In step S11, the controller 20 determines whether or not the sailing stop condition is satisfied. In step S11, if all of the plurality of conditions including the sailing stop condition are satisfied, a positive determination is made, and if not, a negative determination is made. If the negative determination is made in step S11, the process ends once. If a positive determination is made in step S11, sailing stop control is in progress and the process proceeds to step S12.

In step S12, the controller 20 generates the gear ratio of the CVT 13 along the load load line (hereinafter referred to as the R / L line). The road road line is a line that defines the output of the vehicle 100 that balances the running resistance. On the road road line, the accelerator opening is preset according to the vehicle speed. The accelerator opening degree can be further set according to, for example, a road gradient. Vehicle speed and road gradient can be detected by, for example, a sensor.

In step S12, a gear ratio for obtaining the output of the vehicle 100 according to the accelerator opening degree read from the R / L line based on the current vehicle speed is obtained. In step S12, since sailing stop control is in progress, the accelerator opening degree is zero. Therefore, in step S12, a gear ratio for changing the output of the engine 3 when the accelerator opening degree is zero to an output commensurate with the traveling resistance is required.

Based on the output of the engine 3 when the accelerator opening is zero, it is necessary to increase the gear ratio in order to obtain an output commensurate with the running resistance. Therefore, in step S12, the gear ratio is set to a gear ratio on the side larger than the gear ratio set according to the coast line C. In step S12, when the sailing stop condition is satisfied at a vehicle speed of a predetermined vehicle speed VSP1 or higher, the gear ratio is set to a gear ratio on the side where the gear ratio is larger than the minimum gear ratio.

If the gear ratio is along the R / L line, the gear ratio that can obtain the output of the vehicle 100 that balances the running resistance when the accelerator opening is zero is used, so that the gear ratio becomes too low. , It is prevented that the torque becomes excessive when there is an intention to re-accelerate. That is, with such a gear ratio, by setting the gear ratio to the low side, it is possible to prevent a situation in which the torque corresponding to the re-acceleration intention becomes excessive.

During the sailing stop control, the engine 3 is actually stopped, and the MG4 does not generate a driving force either. Therefore, even if the gear ratio is set in this way in step S12, the vehicle speed does not become constant and decreases.

In step S13, the controller 20 determines whether or not the sailing stop release condition is satisfied. The sailing stop release condition is satisfied when any of the plurality of conditions included in the sailing stop condition is no longer satisfied. If a negative determination is made in step S13, the process returns to step S12. If the affirmative determination is made in step S13, the sailing stop control is restored, and the process proceeds to step S14.

In step S14, the controller 20 determines whether the driver intends to re-accelerate. Whether or not there is an intention to re-accelerate can be determined by, for example, whether or not the accelerator opening degree is larger than the predetermined value APO1. The accelerator opening can be detected by, for example, a sensor. The predetermined value APO1 is, for example, zero and is preset. The predetermined value APO1 may be a start request value larger than zero, which is preset as the accelerator opening degree that requires the start of the engine 3.

If a negative determination is made in step S14, the process ends once. In this case, the return from the sailing stop control is performed as usual. If the determination is affirmative in step S14, the process proceeds to step S15.

In step S15, the controller 20 starts engaging the forward clutch 12b by starting the rotation synchronization of the forward clutch 12b. In step S15, the controller 20 also drives the MG4. As a result, torque is output by MG4. By outputting the torque by the MG4, the initial acceleration of the vehicle 100 when returning from the sailing stop control is generated.

In step S15, the controller 20 further maintains the gear ratio. As a result, even if the accelerator pedal is depressed, the gear ratio at which the output of the vehicle 100 that balances the running resistance is obtained when the accelerator opening is zero is maintained as it is.

The gear ratio is the previous value immediately after the accelerator opening becomes larger than zero and before it becomes larger than zero (that is, the gear ratio at which the output of the vehicle 100 that balances the running resistance is obtained when the accelerator opening is zero). Can be maintained. Therefore, when the predetermined value APO1 is set as the start request value of the engine 3, the gear ratio becomes the previous value immediately after the affirmative determination in step S13 as a result of the accelerator opening becoming larger than zero and before becoming larger than zero. Can be maintained.

In step S16, the controller 20 determines whether or not the engagement of the forward clutch 12b is completed. Such a determination can be made based on, for example, the supply oil pressure to the forward clutch 12b. The supply oil pressure to the forward clutch 12b can be detected by, for example, a sensor.

If a negative determination is made in step S16, the process returns to step S15. In this case, in step S15, the engagement operation of the forward clutch 12b is continued. If the determination is affirmative in step S16, the process proceeds to step S17.

In step S17, the controller 20 shifts the CVT 13 to the target gear ratio. That is, in step S17, the target value setting of the gear ratio of the CVT 13 is switched from the gear ratio generated along the R / L line to the target gear ratio. The target gear ratio is a gear ratio obtained based on the gear shift map. After step S17, the process ends once.

FIG. 4 is a diagram showing an example of a timing chart corresponding to the flowchart shown in FIG. The rotation speed Npri indicates the rotation speed of the primary pulley 13a, and the rotation speed Ne indicates the rotation speed of the engine 3. FIG. 4 shows a case where the predetermined value APO1 is set as the start request value of the engine 3.

In FIG. 4, the case of the comparative example is also shown by a alternate long and short dash line. The rotation speed Npri'indicates the rotation speed of the primary pulley 13a in the case of the comparative example. A comparative example shows a case where the gear shift is performed according to the coast line C during sailing stop control, and the torque is not output by MG4 when returning from the sailing stop.

Prior to the timing T1, steady running is performed in which the accelerator opening and the vehicle speed are constant. Therefore, the rotation speed Npri and the rotation speed Ne are also constant, and the acceleration is zero. Before the timing T1, the gear ratio is a gear ratio along the R / L line.

At timing T1, the depression of the accelerator pedal begins to be relaxed, and the vehicle speed begins to decrease accordingly. The accelerator opening becomes zero at the timing T2. At the timing T2, the sailing stop condition is satisfied accordingly, and the sailing stop control is started. As a result, the rotation speed Ne and the acceleration start to decrease significantly from the timing T2. The rotation speed Ne then becomes zero, and the acceleration then becomes constant.

In the case of the comparative example, the gear ratio is a gear ratio according to the coast line C. Therefore, the gear ratio starts to be changed from the timing T2 to the smaller side, that is, the high side, and the rotation speed Npri'also starts to decrease accordingly. Then, when the target gear ratio according to the vehicle speed becomes larger than the current gear ratio, the gear ratio starts to be changed to the larger gear ratio side, that is, the low gear ratio, and the rotation speed Npri'becomes constant. That is, in the case of the comparative example, the gear ratio is once changed to the high side and then changed to the low side according to the satisfaction of the sailing stop condition.

In the case of this embodiment, the gear ratio is set to the gear ratio along the R / L line. Therefore, the gear ratio starts to be changed from the timing T2 to the low side. That is, in the case of this embodiment, the gear ratio is changed to the low side when the sailing stop condition is satisfied. As a result, the rotation speed Npri does not decrease significantly as in the case of the comparative example.

As described above, even if the gear ratio is set to the gear ratio along the R / L line, the engine 3 is stopped during the sailing stop control, so that the output of the vehicle 100 balanced with the running resistance is actually obtained. However, the vehicle speed continues to decrease. As a result, the rotation speed Npri gradually decreases accordingly.

At the timing T3, the sailing stop release condition is satisfied when the accelerator opening becomes larger than zero. Further, at the timing T4, when the accelerator opening degree becomes larger than the predetermined value APO1, it is determined that there is a re-acceleration intention. As a result, the start of the engine 3 is started from the timing T4, and the rotation speed Ne starts to increase.

In the case of the comparative example, the engagement of the forward clutch 12b is started from the timing T4, and the engagement of the forward clutch 12b is completed at the timing T5. As a result, the acceleration increases stepwise at timing T5.

In the case of the comparative example, the low return of the gear ratio for changing the gear ratio to the low side is started from the timing T5, and the low return is completed at the timing T8. Between the timing T5 and the timing T8, since the driving force obtained is smaller than the driving force obtained when the gear ratio is the lowest gear ratio, the acceleration is impaired accordingly.

In the case of the present embodiment, even if the accelerator opening becomes larger than zero at the timing T3, the gear ratio is the previous value before the accelerator opening becomes larger than zero, that is, the running resistance when the accelerator opening is zero. The output of the balanced vehicle 100 is maintained at a gear ratio that is obtained.

In the case of the present embodiment, the engagement of the forward clutch 12b is started at the timing T5, that is, after the start of the engine 3 is started, in response to the determination at the timing T4 that there is an intention to re-accelerate. The engagement of the forward clutch 12b ends at the timing T6, and from the timing T6, the target value setting of the gear ratio is changed from the gear ratio generated along the R / L line to the target gear ratio based on the gear shift map.

In the case of the present embodiment, the low return of the gear ratio is started by this, but at the timing T6, the gear ratio is on the low side as compared with the case of the comparative example. Therefore, the time required to return the gear ratio to low is shorter than in the case of the comparative example, and the low return is completed at the timing T7 before the timing T8.

In the case of the present embodiment, as can be seen from the comparison between the inclination of the rotation speed Ne between the timings T4 and T5 and the inclination of the rotation speed Ne between the timings T5 and T6, the gear ratio is on the low side. , The time required to increase the rotation speed of the engine 3 becomes longer.

However, in the case of this embodiment, the driving of the MG4 is also started at the timing T5, and the torque is output by the MG4. Therefore, even if the time required for the rotation increase of the engine 3 becomes long, the driving torque during the rotation increase of the engine 3 is secured by the MG4.

As a result, the engagement of the forward clutch 12b is not completed, and the acceleration is secured even between the timings T5 and T6 at which the vehicle 100 runs idle under the power of the engine 3. At the timing T5, the acceleration increases stepwise more than in the case of the comparative example, and the initial acceleration of the vehicle 100 when returning from the sailing stop control is also secured. As a result of securing the driving force by MG4 in this way, the vehicle speed starts to increase from the timing T5.

In the case of the present embodiment, the low return is completed at the timing T7 before the timing T8, so that the timing at which the acceleration reaches the peak becomes earlier than in the case of the comparative example. That is, the period during which the driving force smaller than the driving force obtained when the gear ratio is the lowest gear ratio is obtained is only between timings T6 and T7, which is shorter than that between timings T5 and T8 in the comparative example. ..

Next, the main effects of the present embodiment will be described.

The vehicle 100 is connected to the engine 3, the CVT 13 to which power is transmitted from the engine 3, the forward clutch 12b and the reverse brake 12c that connect and disconnect the power transmission path connecting the engine 3 and the CVT 13, and the shaft of the primary pulley 13a of the CVT 13. A hybrid vehicle including the MG4 to be used is configured. The vehicle 100 includes a controller 20 that outputs torque by MG4 when returning from sailing stop control, which is an example of engine stop control.

According to such a configuration, when returning from the sailing stop control, the torque is output by the MG 4, so that the driving torque during the increase in the rotation of the engine 3 until the engagement of the forward clutch 12b is completed can be secured. Therefore, according to such a configuration, a desired driving force can be quickly secured when returning from the sailing stop control (effect corresponding to claims 1 and 5).

In the present embodiment, the sailing stop control that releases the forward clutch 12b and the reverse brake 12c to stop the engine 3 during traveling constitutes the engine stop control. The controller 20 further sets the gear ratio of the CVT 13 to a gear ratio larger than the minimum gear ratio during sailing stop control.

According to such a configuration, by setting the gear ratio to the highest gear ratio, that is, the gear ratio on the lower side than the minimum gear ratio during sailing stop control, the gear shifts to the low side when returning from sailing stop control. You can shorten the time. In this case, the time required to increase the rotation of the engine becomes longer because the gear ratio becomes the low side, but according to such a configuration, the driving torque during the increase in the rotation of the engine 3 is obtained by outputting the torque with the MG4. Can also be secured. Therefore, according to such a configuration, it is possible to appropriately recover from the sailing stop control (effect corresponding to claim 2).

During sailing stop control, the controller 20 sets the gear ratio of the CVT 13 to a gear ratio that can obtain an output corresponding to the accelerator opening that balances the traveling resistance.

According to such a configuration, as a result of the gear ratio becoming too low, it is possible to prevent the torque from becoming excessive when there is an intention of re-acceleration (effect corresponding to claim 3).

The controller 20 outputs torque by MG4 when there is an intention of re-acceleration.

According to such a configuration, the initial acceleration of the vehicle 100 when returning from the sailing stop control can be appropriately generated (effect corresponding to claim 4).

The vehicle 100 further includes a reduction mechanism DM that decelerates the output rotation of the MG 4 and transmits it to the shaft of the primary pulley 13a.

In this case, the required drive torque can be obtained even if a relatively small MG4 is used, but the effect of the MG4 as a load is increased by the deceleration mechanism DM during sailing stop control, so that the speed is changed to the low side. It becomes easy to take time. Therefore, in the case of such a configuration, the vehicle 100 can not only secure the driving force but also eliminate the action as the load of the MG4 by outputting the torque by the MG4, which is particularly effective. (Effect corresponding to claim 5).

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configurations of the above embodiments. Absent.

In the above-described embodiment, a case where sailing stop control is performed as engine stop control has been described. However, the engine stop control may be, for example, coast stop control or idle stop control.

The coast stop control is executed when the coast stop condition is satisfied. The coast stop conditions are that the vehicle speed is low (less than the preset vehicle speed), that the accelerator pedal is not depressed, that the brake pedal is depressed, that the forward range is selected by the transmission, and that the vehicle speed is selected. It is a condition including. The set vehicle speed is, for example, a vehicle speed at which the lockup clutch 11a is released.

The idle stop control is executed when the idle stop condition is satisfied. The idle stop condition includes that the vehicle speed is zero, that the brake pedal is depressed, and that the accelerator pedal is not depressed.

The idle stop condition is satisfied when all of the plurality of conditions included in the idle stop condition are satisfied, and is not satisfied when any one of the plurality of conditions included in the idle stop condition is not satisfied. When the idle stop condition is satisfied, the engine 3 is stopped, and when the idle stop condition is not satisfied, the engine 3 is started. The same applies to the coast stop condition.

Even in these cases, it is effective when the gear ratio is not returned to the lowest gear ratio when returning from the engine stop control, or when a low return is required when returning from the engine stop control. (Effect corresponding to claim 1).

Further, in these cases, even when the vehicle 100 is provided with the reduction mechanism DM, a great effect can be obtained (effect corresponding to claim 5).

In the above-described embodiment, the case where the control unit is realized by the controller 20 has been described. However, the control unit may be realized by, for example, a plurality of controllers.

1: Low voltage battery 2: High voltage battery 3: Engine 4: Motor generator 5: Starter motor 6: Starter generator 7: DC-DC converter 8: Inverter 9: Mechanical oil pump 10: Electric oil pump 12: Forward / backward switching mechanism 12b: Forward clutch (clutch)
12c: Reverse brake (clutch)
13: Continuously variable transmission mechanism 13a: Primary pulley 15: Electrical components 15a: Camera 15b: Sensor 16: Low voltage circuit 17: High voltage circuit 18: Drive wheel 20: Controller (control unit)
31: Electric motor 100: Hybrid vehicle DM: Deceleration mechanism

Claims (6)

With the engine
A continuously variable transmission mechanism in which power is transmitted from the engine,
A clutch that connects and disconnects the power transmission path that connects the engine and the continuously variable transmission mechanism,
A motor connected to the power transmission path on the drive wheel side of the clutch,
It is a hybrid vehicle equipped with
A control unit that outputs torque by the motor when returning from engine stop control,
A hybrid vehicle characterized by being equipped with. The hybrid vehicle according to claim 1.
The engine stop control is a sailing stop control that releases the clutch and stops the engine during traveling.
The control unit further sets the gear ratio of the continuously variable transmission mechanism to a gear ratio on the side larger than the minimum gear ratio during the sailing stop control.
A hybrid vehicle characterized by being equipped with. The hybrid vehicle according to claim 2.
During the sailing stop control, the control unit sets the gear ratio of the continuously variable transmission mechanism to a gear ratio that can obtain an output corresponding to the accelerator opening degree that balances the traveling resistance.
A hybrid vehicle that features that. The hybrid vehicle according to claim 2 or 3.
The control unit outputs torque by the motor when there is an intention to re-accelerate.
A hybrid vehicle that features that. The hybrid vehicle according to any one of claims 1 to 4.
A deceleration mechanism that decelerates the output rotation of the motor and transmits it to the shaft of the primary pulley is further provided.
A hybrid vehicle that features that. The engine, the continuously variable transmission mechanism to which power is transmitted from the engine, the clutch that connects and disconnects the power transmission path connecting the engine and the continuously variable transmission mechanism, and the power transmission path on the drive wheel side of the clutch are connected. It is a control method of a hybrid vehicle including a motor to be clutched.
To output torque by the motor when returning from engine stop control,
A method for controlling a hybrid vehicle, which comprises.

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