JP7192844B2 - Hybrid vehicle control device - Google Patents

Description

The present invention relates to a hybrid vehicle control device.

2. Description of the Related Art Conventionally, as a hybrid vehicle that outputs a motor torque of a motor generator and an engine torque of an engine to a drive shaft via a power transmission mechanism, one described in Patent Document 1 is known. The vehicle described in Patent Document 1 includes two motor generators and an engine, and is designed to prevent the engine from stalling due to a drop in engine rotational speed when the vehicle suddenly decelerates.

Specifically, in Patent Document 1, a rotation speed higher than the stall limit rotation speed of the engine is set as a lower limit, and the motor generator and the controlling the engine.

JP 2006-299993 A

However, although the technique described in Patent Document 1 can prevent the engine from stalling when the vehicle suddenly decelerates, it cannot prevent the engine rotation speed from dropping to the resonance region of the engine. For this reason, the engine disclosed in Patent Document 1 may cause the engine rotation speed to decrease to the resonance region, causing the engine to vibrate.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a control device for a hybrid vehicle that can prevent the engine from vibrating due to staying in the resonance region while the engine rotation speed is decreasing.

One aspect of the hybrid vehicle control device for solving the above problem is a hybrid vehicle control device that includes a control unit that controls a motor generator and an engine, and is capable of transmitting motor torque of the motor generator to the engine. , the control unit performs resonance prevention control for reducing the engine rotation speed of the engine by the motor torque in a resonance region where the engine resonates, and by the engine torque of the engine without the motor generator generating the motor torque. a first predetermined value greater than an upper limit value of the resonance region; and a second predetermined value greater than the first predetermined value. and, when the engine rotation speed drops and becomes equal to or less than the second predetermined value, the engine autonomous control is prohibited, and the brake depression amount is increased, thereby causing the engine rotation speed to drop. When the vehicle becomes equal to or less than the first predetermined value, the vehicle is shifted to an EV driving mode in which the vehicle is driven by the motor torque while the engine is stopped, and the resonance prevention control is executed.

Thus, according to one aspect of the present invention, it is possible to prevent the engine from staying in the resonance region and vibrating while the engine rotation speed is decreasing.

FIG. 1 is a diagram showing a hybrid vehicle control device according to an embodiment of the present invention, and is a configuration diagram of the hybrid vehicle. FIG. 2 is a diagram for explaining a hybrid vehicle control device according to an embodiment of the present invention, showing the relationship between the lever lengths of the engine of the hybrid vehicle, the drive shaft, the first motor generator, and the second motor generator at each rotation speed. It is a nomographic chart showing . FIG. 3 is a diagram for explaining a hybrid vehicle control apparatus according to an embodiment of the present invention, showing the relationship among the rotational speeds of the engine, drive shaft, first motor generator, and second motor generator during sudden deceleration of the vehicle. It is a nomographic chart showing . FIG. 4 is a diagram for explaining the hybrid vehicle control device according to the embodiment of the present invention, and is a flowchart for explaining resonance prevention control when the shift position is in the P range or the N range. FIG. 5 is a diagram illustrating a hybrid vehicle control apparatus according to an embodiment of the present invention, and is a flowchart illustrating resonance prevention control when the shift position is in the R range. FIG. 6 is a diagram for explaining the hybrid vehicle control device according to the embodiment of the present invention, and is a flowchart for explaining resonance prevention control when the shift position is in the D range. FIG. 7 is a diagram for explaining a hybrid vehicle control apparatus according to an embodiment of the present invention. When the shift position is in P range or N range, engine resonance is prevented without stopping the engine. 4 is a time chart showing vehicle states; FIG. 8 is a diagram for explaining a hybrid vehicle control apparatus according to an embodiment of the present invention. When the shift position is in the P range or the N range, the engine is stopped to prevent engine resonance. It is a time chart which shows a state. FIG. 9 is a diagram for explaining a hybrid vehicle control apparatus according to an embodiment of the present invention. When the shift position is in the D range or the B range, the engine is stopped to prevent engine resonance. It is a time chart which shows a state. FIG. 10 is a diagram for explaining a hybrid vehicle control apparatus according to an embodiment of the present invention. When the shift position is in the R range, the vehicle state when preventing engine resonance without stopping the engine is shown. It is a time chart showing.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, a hybrid vehicle (hereinafter simply referred to as "vehicle") 1 equipped with a control device according to an embodiment of the present invention includes an internal combustion engine 2, a first motor generator 4, and a 2 motor generator 5, drive wheel 6, drive shaft 7 connected to drive wheel 6 so as to be able to transmit power, first planetary gear mechanism 8, second planetary gear mechanism 9, first inverter 19, It includes a second inverter 20, a hybrid ECU (Electronic Control Unit) 32, an engine ECU (Electronic Control Unit) 33, a motor ECU (Electronic Control Unit) 34, and a battery ECU (Electronic Control Unit) 35. be.

The engine 2 is a four-cycle engine that performs a series of four strokes consisting of an intake stroke, a compression stroke, an expansion stroke and an exhaust stroke. An output shaft 3 of the engine 2 is connected to a first planetary gear mechanism 8 and a second planetary gear mechanism 9 .

The first motor generator 4 has a rotor shaft 13 , a rotor 14 and a stator 15 . A plurality of permanent magnets are embedded in the rotor 14 . The stator 15 has a stator core and a three-phase coil wound around the stator core. A three-phase coil of the stator 15 is connected to the first inverter 19 .

In the first motor generator 4 configured as described above, when three-phase AC power is supplied to the three-phase coils of the stator 15 , the stator 15 forms a rotating magnetic field. A permanent magnet embedded in the rotor 14 is attracted to this rotating magnetic field, so that the rotor 14 is rotationally driven around the rotor shaft 13 . That is, the first motor generator 4 functions as an electric motor and can generate driving force for driving the vehicle 1 .

When the rotor 14 rotates around the rotor shaft 13, a rotating magnetic field is formed by the permanent magnets embedded in the rotor 14. This rotating magnetic field induces an induced current in the three-phase coils of the stator 15, thereby generating a three-phase alternating current. Electricity is generated. That is, the first motor generator 4 also functions as a generator.

The first inverter 19 converts DC power supplied from the battery 21 or the like into three-phase AC power under the control of the motor ECU 34 . This three-phase AC power is supplied to the three-phase coils of the stator 15 of the first motor generator 4 .

The first inverter 19 converts the three-phase AC power generated by the first motor generator 4 into DC power under the control of the motor ECU 34 . This DC power charges the battery 21, for example.

The second motor generator 5 has a rotor shaft 16 , a rotor 17 and a stator 18 . A plurality of permanent magnets are embedded in the rotor 17 . The stator 18 has a stator core and a three-phase coil wound around the stator core. A three-phase coil of the stator 18 is connected to the second inverter 20 .

In the second motor generator 5 configured as described above, when three-phase AC power is supplied to the three-phase coils of the stator 18, the stator 18 forms a rotating magnetic field. A permanent magnet embedded in the rotor 17 is attracted to this rotating magnetic field, so that the rotor 17 is rotationally driven around the rotor shaft 16 . That is, the second motor generator 5 functions as an electric motor and can generate driving force for driving the vehicle 1 .

When the rotor 17 rotates around the rotor shaft 16, a rotating magnetic field is formed by the permanent magnets embedded in the rotor 17. This rotating magnetic field induces an induced current in the three-phase coils of the stator 18, thereby generating a three-phase alternating current. Electricity is generated. That is, the second motor generator 5 also functions as a generator.

The second inverter 20 converts DC power supplied from the battery 21 or the like into three-phase AC power under the control of the motor ECU 34 . This three-phase AC power is supplied to the three-phase coils of the stator 18 of the second motor generator 5 .

The second inverter 20 converts the three-phase AC power generated by the second motor generator 5 into DC power under the control of the motor ECU 34 . This DC power charges the battery 21, for example.

The first planetary gear mechanism 8 includes a sun gear 22, a plurality of planetary gears 23 meshing with the sun gear 22, a ring gear 25 meshing with the plurality of planetary gears 23, and a planetary carrier 24 rotatably supporting the planetary gears 23. ing.

The second planetary gear mechanism 9 includes a sun gear 26, a plurality of planetary gears 27 meshing with the sun gear 26, a ring gear 29 meshing with the plurality of planetary gears 27, and a planetary carrier 28 supporting the planetary gears 27 rotatably. ing.

The sun gear 22 of the first planetary gear mechanism 8 is connected to the hollow rotor shaft 13 so as to rotate integrally with the rotor 14 of the first motor generator 4 . The planetary carrier 24 of the first planetary gear mechanism 8 and the sun gear 26 of the second planetary gear mechanism 9 are connected to rotate integrally with the output shaft 3 of the engine 2 .

A planetary gear 27 of the second planetary gear mechanism 9 is connected to the ring gear 25 of the first planetary gear mechanism 8 via a planetary carrier 28 so as to revolve around the rotor shaft 13 . The ring gear 25 of the first planetary gear mechanism 8 is provided to rotate the drive shaft 7 via a gear mechanism 31 including a differential gear (not shown) and other gears. The ring gear 29 of the second planetary gear mechanism 9 is connected to the rotor shaft 16 so as to rotate integrally with the rotor 17 of the second motor generator 5 .

The first planetary gear mechanism 8 and the second planetary gear mechanism 9 constitute a power transmission mechanism 10 . The power transmission mechanism 10 constitutes a planetary gear mechanism in which the output shaft 3 of the engine 2, the rotor shaft 13 of the first motor generator 4, the rotor shaft 16 of the second motor generator 5, and the drive shaft 7 are connected. .

In this manner, the power transmission mechanism 10 allows the engine 2 , the first motor generator 4 , the second motor generator 5 , and the drive shaft 7 to transmit and receive driving force. For example, the power transmission mechanism 10 transmits power generated by the engine 2 , the first motor generator 4 , and the second motor generator 5 to the drive shaft 7 .

The hybrid ECU 32, the engine ECU 33, the motor ECU 34, and the battery ECU 35 include a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data and the like, and an input Each is composed of a computer unit with a port and an output port.

The ROMs of these computer units store programs for causing the computer units to function as the hybrid ECU 32, the engine ECU 33, the motor ECU 34, and the battery ECU 35, along with various constants and maps.

That is, when the CPU executes programs stored in the ROM using the RAM as a work area, these computer units function as the hybrid ECU 32, the engine ECU 33, the motor ECU 34, and the battery ECU 35 in the present embodiment.

The vehicle 1 is provided with a CAN communication line 39 for forming an in-vehicle LAN (Local Area Network) conforming to standards such as CAN (Controller Area Network). The hybrid ECU 32 , the engine ECU 33 , the motor ECU 34 and the battery ECU 35 mutually transmit and receive signals such as control signals via the CAN communication line 39 .

The hybrid ECU 32 mainly controls various ECUs such as the engine ECU 33, the motor ECU 34 and the battery ECU 35 in an integrated manner. The engine ECU 33 mainly controls the engine 2 .

The motor ECU 34 mainly controls the first motor generator 4 and the second motor generator 5 via the first inverter 19 and the second inverter 20 . Battery ECU 35 mainly manages the state of battery 21 .

In this embodiment, an input port of the hybrid ECU 32 is connected to various sensors including an accelerator opening sensor 41 , a shift position sensor 42 and a vehicle speed sensor 43 .

The accelerator opening sensor 41 detects the depression amount of the accelerator pedal (not shown) by the driver as the accelerator opening. A shift position sensor 42 detects the shift position selected by the driver's operation of the shift lever.

In this embodiment, the vehicle 1 has, as shift positions, P range (parking position), R range (reverse position), N range (neutral position), D range (forward normal driving position), B range (engine braking). position). The B range is a shift position that produces greater engine braking than the D range. The shift position sensor 42 constitutes a shift position detector in the present invention.

The vehicle speed sensor 43 detects the vehicle speed from the rotational speed of the drive shaft 7, for example. The vehicle speed sensor 43 outputs a positive vehicle speed when the vehicle 1 is traveling forward, and outputs a negative vehicle speed when the vehicle is traveling backward.

The engine ECU 33 controls the engine 2 according to the torque command signal from the hybrid ECU 32 so that the engine torque generated by the engine 2 becomes the torque command value set in the torque command signal. The engine ECU 33 controls the fuel injection amount and the intake air amount by controlling injectors and throttle valves (not shown). The engine ECU 33 controls the engine torque generated by the engine 2 by controlling the fuel injection amount and the intake air amount.

A battery state detection sensor 45 is connected to an input port of the battery ECU 35 . A battery state detection sensor 45 detects charge/discharge current, voltage, and battery temperature of the battery 21 . The battery ECU 35 detects the state of charge (hereinafter referred to as SOC) of the battery 21 based on the charge/discharge current value, voltage value, and battery temperature value input from the battery state detection sensor 45 .

For the battery state detection sensor 45, for example, a configuration in which a voltage sensor for detecting voltage and a battery temperature sensor for detecting battery temperature are attached to a current sensor for detecting charging/discharging current of the battery 21 can be used. Note that the current sensor, voltage sensor, and battery temperature sensor may be provided separately.

In such a vehicle 1, the hybrid ECU 32 sets the target acceleration based on the accelerator opening detected by the accelerator opening sensor 41, the shift position detected by the shift position sensor 42, the vehicle speed detected by the vehicle speed sensor 43, and the like. The driving power is calculated, and the engine 2, the first motor generator 4, and the second motor generator 5 are controlled so as to output the target driving power to the drive shaft 7.

In this embodiment, the power means the power proportional to the value obtained by multiplying the torque by the rotation speed. is uniquely determined by the combination of torque and rotational speed at

The hybrid ECU 32 determines the target drive torque by referring to, for example, a torque map that defines the correlation of the target drive torque with the accelerator opening, the shift position, and the vehicle speed. The hybrid ECU 32 then determines the target drive power from the target drive torque and the vehicle speed. The torque map is obtained in advance through experiments or the like and stored in the ROM of the hybrid ECU 32 .

The hybrid ECU 32 calculates the target engine power and the target motor power with appropriate distribution according to the vehicle state and the like so as to satisfy the target drive power. The hybrid ECU 32 then calculates a target engine rotation speed and a target engine torque based on the target engine power, and calculates a target motor rotation speed and a target motor torque based on the target motor power.

When the target engine speed and the target engine torque are determined by the hybrid ECU 32, the engine ECU 33 converts these target values into control variables such as throttle valve opening and ignition timing, and determines the target engine speed and the target engine torque. Control the engine 2 to achieve

When the hybrid ECU 32 determines the target motor rotation speed and the target motor torque, the motor ECU 34 converts these target values into control amounts for the first motor generator 4 and the second motor generator 5 to obtain the target motor rotation speed and the target motor torque. The first motor generator 4 and the second motor generator 5 are controlled to achieve motor torque.

The hybrid ECU 32 determines the target engine rotation speed and target engine torque by referring to, for example, a power map that defines the correlation of engine power with respect to engine torque and engine rotation speed. The hybrid ECU 32 determines the target engine rotation speed and the target engine torque based on the optimum fuel efficiency line of the power map (not shown). This power map is obtained in advance through experiments or the like and stored in the ROM of the hybrid ECU 32 . The hybrid ECU 32 controls the operating point of the engine 2 so as to move along the optimum fuel consumption line of the power map.

2 and 3 are alignment charts of the vehicle 1. FIG. FIG. 2 is a collinear chart when the vehicle is stopped. FIG. 3 is a collinear chart of the vehicle 1 before and during rapid deceleration. 2 and 3, each vertical axis represents the rotational speed of the first motor generator 4 (denoted as MG1 in the drawing) and the rotation speed of the engine 2 (denoted as engine in the drawing) from the left in the drawing. The speed (engine rotation speed), the rotation speed of the drive shaft 7 (indicated as output in the drawing), and the rotation speed of the second motor generator 5 (indicated as MG2 in the drawing) are respectively shown.

In the collinear chart, the rotational speeds of the first motor generator 4, the second motor generator 5, and the drive shaft 7 are positive when the vehicle 1 moves forward.

Here, assuming that the engine speed is Neng, the speed of the drive shaft 7 is Nout, the speed of the first motor generator 4 is Nmg1, and the speed of the second motor generator 5 is Nmg2, between these speeds: holds the relationships of the following equations (1) and (2).

In equations (1) and (2), the lever length between the engine 2 and the drive shaft 7 is 1, the lever length between the engine 2 and the first motor generator 4 is k1, and the drive shaft 7 and the first motor generator 4 are k1. The lever length between the two motor generators 5 is k2.

Nmg1=(1+k1)Neng−k1·Nout...(1)
Nmg2=(1+k2)Nout−k2·Neng...(2)
In the nomographic chart of FIG. 2, the distance ratio (lever length ratio) between the axes on the horizontal axis is determined by the ratio of the number of teeth of the gears of the first planetary gear mechanism 8 and the second planetary gear mechanism 9. . Here, k1 is Zr1/Zs1, which is the ratio of the ring gear number of teeth Zr1 and the sun gear number of teeth Zs1 of the first planetary gear mechanism 8 . k2 is a ratio Zs2/Zr2 of the number of teeth of the sun gear Zs2 and the number of teeth of the ring gear Zr2 of the second planetary gear mechanism 9;

As shown by the solid lines in FIG. 3, before the vehicle 1 suddenly decelerates, the rotational speed of the first motor generator 4 (Nmg1), the rotational speed of the engine 2 (Neng), the rotational speed of the second motor generator 5 (Nmg2 ), and the rotation speed (Nout) of the drive shaft 7 is a positive value.

In this state, the engine 2 is running, and the vehicle 1 is running with the engine torque of the engine 2 and the motor torques of both the first motor generator 4 and the second motor generator 5 .

After that, the vehicle 1 suddenly decelerates due to the driver's sudden braking operation, so the rotation speed (Nout) of the drive shaft 7 decreases as indicated by the dashed line in FIG. In the collinear chart of FIG. 3, even if the rotational speed of the drive shaft 7 decreases due to the large inertia of the second motor generator 5, the rotational speed (Nmg2) of the second motor generator 5 does not change from before the rapid deceleration. not On the other hand, the rotation speed of the first motor generator 4, the rotation speed of the drive shaft 7, and the engine rotation speed decrease so as to use the second motor generator 5 as a fulcrum.

When the vehicle 1 suddenly decelerates in this manner, the engine rotation speed (Neng) may drop to the resonance region. The resonance region is a region of engine rotation speed in which the engine 2 resonates. More specifically, the resonance region is the region of low engine speed.

When the engine rotation speed decreases and the engine 2 resonates, the passenger feels uncomfortable. For this reason, in the present embodiment, the hybrid ECU 32 prevents the resonance of the engine 2 by performing the following various controls. Hybrid ECU32 comprises the control part in this invention.

The hybrid ECU 32 controls the first motor-generator 4 and the second motor-generator 5 so that the engine 2 is stopped by the motor torque when the engine rotation speed of the engine 2 decreases to a first predetermined value or less. . The first predetermined value is a value greater than the upper limit of the resonance region.

The hybrid ECU 32 can implement engine autonomous control. Autonomous engine control is control in which the first motor generator 4 and the second motor generator 5 do not generate motor torque and the engine rotation speed is autonomously adjusted by the engine torque of the engine 2 .

The hybrid ECU 32 carries out autonomous idle speed control as this engine autonomous control. The autonomous idle speed control is a control in which the first motor generator 4 and the second motor generator 5 do not generate motor torque and the idle rotation speed is autonomously adjusted by the engine torque of the engine 2 .

The hybrid ECU 32 prohibits the autonomous engine control when the engine rotation speed decreases to be equal to or less than a second predetermined value that is larger than the first predetermined value while the engine autonomous control is being executed.

Further, when the hybrid ECU 32 prohibits the engine autonomous control, the hybrid ECU 32 controls the first motor generator 4 and the second motor generator 5 so as to increase the engine rotation speed by the motor torque.

Further, the hybrid ECU 32 detects that the shift position is in the P range or the N range by the shift position sensor 42, and when the engine rotation speed decreases to be equal to or lower than the second predetermined value, the engine Prohibit autonomous control.

In addition, the hybrid ECU 32 detects that the shift position is in the R range by the shift position sensor 42, and the engine rotation speed increases and the hybrid ECU 32 receives a third predetermined value that is smaller than the lower limit value of the resonance region. In the above case, the first motor generator 4 and the second motor generator 5 are controlled so as to reduce the engine rotation speed by the motor torque.

In addition, the hybrid ECU 32 changes the running mode from the HEV running mode to the EV running mode when the engine rotation speed of the engine 2 decreases to a first predetermined value or less. The HEV running mode is a mode in which the vehicle 1 can run with at least two torques out of three torques, that is, the engine torque of the engine 2 , the motor torque of the first motor generator 4 , and the motor torque of the second motor generator 5 . The EV travel mode is a mode in which the vehicle travels with motor torque while the engine 2 is stopped.

Resonance prevention control performed by the hybrid ECU 32 in the hybrid vehicle control apparatus according to the present embodiment configured as described above will be described with reference to flowcharts of FIGS. 4, 5, and 6. FIG. 4, 5, and 6 are started when the hybrid ECU 32 is activated.

In the flowchart of FIG. 4, the hybrid ECU 32 determines whether the shift position is in the P range or the N range (step S11).

When it is determined in step S11 that the shift position is in the P range or the N range, the hybrid ECU 32 determines whether or not the engine rotation speed (denoted as Neg in the drawing) is equal to or less than a second predetermined value (step S12).

When determining in step S11 that the shift position is not in the P range or the N range, the hybrid ECU 32 advances the process to step S15, which will be described later.

When the determination in step S12 is YES (when the engine rotation speed is equal to or lower than the second predetermined value), the hybrid ECU 32 prohibits the engine autonomous control (step S13), and proceeds to step S15.

When the engine rotation speed feedback control is effective, the hybrid ECU 32 increases the engine rotation speed when the engine 2 is about to stall, so that the engine 2 continues to rotate autonomously. 1 motor generator 4 and second motor generator 5 are controlled.

When the determination in step S12 is NO (when the engine rotation speed is greater than the second predetermined value), the hybrid ECU 32 permits the engine autonomous control (step S14), and terminates the current operation.

In step S15, the hybrid ECU 32 determines whether or not the engine speed is equal to or less than a first predetermined value. The first predetermined value is set to a value smaller than the second predetermined value. Also, the first predetermined value is set to a value larger than the upper limit of the resonance region of the engine 2 . Therefore, when the engine rotation speed is equal to or lower than the first predetermined value, it means that the engine rotation speed has decreased to near the resonance region.

If it is determined in step S15 that the engine rotation speed is equal to or lower than the first predetermined value, the hybrid ECU 32 stops the engine 2 (step S16) and terminates the current operation.

In step S<b>16 , the hybrid ECU 32 causes the first motor generator 4 and the second motor generator 5 to generate motor torque for stopping the engine 2 . As a result, the engine rotation speed rapidly decreases due to the motor torques of the first motor generator 4 and the second motor generator 5, and the engine 2 quickly passes through the resonance region and stops.

When determining in step S15 that the engine rotation speed is greater than the first predetermined value, the hybrid ECU 32 terminates the current operation.

In the flowchart of FIG. 5, the hybrid ECU 32 determines whether or not the shift position is in the R range (step S21).

If it is determined in step S21 that the shift position is in the R range, the hybrid ECU 32 determines whether or not the engine speed (denoted as Neg in the drawing) is equal to or less than a third predetermined value (step S22).

If it is determined in step S21 that the shift position is not in the R range, the hybrid ECU 32 ends this operation.

If it is determined in step S22 that the engine rotation speed is equal to or lower than the third predetermined value, the hybrid ECU 32 stops the engine 2 (step S23) and terminates the current operation.

Specifically, the hybrid ECU 32 stops the engine 2 by the motor torque of the first motor generator 4 and the second motor generator 5 . Therefore, the engine rotation speed is prevented from entering the resonance region.

When determining in step S22 that the engine rotation speed is greater than the third predetermined value, the hybrid ECU 32 terminates the current operation.

In the flowchart of FIG. 6, the hybrid ECU 32 determines whether or not the shift position is in the D range (step S31).

When it is determined in step S31 that the shift position is in the D range, the hybrid ECU 32 determines whether the target driving force is smaller than the default value and the SOC is greater than the default value (step S32).

If it is determined in step S31 that the shift position is not in the D range, the hybrid ECU 32 terminates the current operation.

If the determination in step S32 is NO (if the target driving force is greater than the default value or the SOC is less than the default value), the hybrid ECU 32 determines whether the deceleration of the vehicle 1 is greater than the default value (step S33).

If the determination in step S32 is YES (if the target driving force is smaller than the default value and the SOC is larger than the default value), the hybrid ECU 32 proceeds to step S35.

If the determination in step S33 is YES (if the deceleration of the vehicle 1 is greater than the default value), the hybrid ECU 32 determines whether the engine rotation speed (denoted as Neg in the figure) is equal to or less than a first predetermined value. It is determined (step S34).

If it is determined in step S34 that the engine rotation speed is equal to or lower than the first predetermined value, the hybrid ECU 32 executes step S35 and then terminates the current operation. In step S35, the hybrid ECU 32 changes the running mode to the EV running mode (step S35).

If the determination in step S33 is NO, and if the determination in step S34 is NO, the hybrid ECU 32 ends the current operation while maintaining the HEV running mode as the running mode.

Next, changes in the vehicle state and control state when the resonance prevention control shown in FIGS. 4, 5 and 6 are performed will be described with reference to the time charts shown in FIGS. 7, 8, 9 and 10. . In the figure, the engine rotation speed indicated by a solid line indicates the transition due to the control of this embodiment. Also, the engine rotation speed indicated by the dashed line indicates the transition due to the conventional control.

7 and 8, when the shift position is in the P range or the N range and the engine autonomous control (indicated as ISC control in the figure) is being performed, the engine rotation speed suddenly decreases due to the driver's sudden brake operation. indicates the case.

In FIG. 7, at time t11, the accelerator opening and the brake depression amount are both 0, and the vehicle 1 is coasting. At time t11, the vehicle speed is slowly decreasing.

After that, at time t12, the driver performs a sudden brake operation and the amount of brake depression increases, so the vehicle speed and the engine rotation speed start to decrease rapidly.

After that, at time t13, the engine autonomous control is prohibited in this embodiment in response to the engine rotation speed becoming smaller than the second predetermined value. Since the engine autonomous control is prohibited, the engine speed feedback control is performed. After that, the engine rotation speed feedback control is performed, so that the engine rotation speed starts to increase and returns to a rotation speed equivalent to the engine rotation speed at time t11.

On the other hand, in the conventional technology, since the engine autonomous control is not prohibited at time t13, the engine rotation speed continues to decrease toward 0 after time t3 as indicated by the dashed line. While the engine speed is decreasing to zero, the engine speed passes through the resonance region.

In FIG. 8, at time t21, both the accelerator opening and the brake depression amount are 0, and the vehicle 1 is coasting. At this time t21, the vehicle speed is gradually decreasing.

After that, at time t22, the driver performs a sudden brake operation and the amount of brake depression increases, so the vehicle speed and the engine rotation speed start to decrease rapidly.

After that, at time t23, the engine autonomous control is prohibited in the present embodiment in response to the engine rotation speed becoming smaller than the second predetermined value. Since the engine autonomous control is prohibited, the engine speed feedback control is performed. In FIG. 8, the engine rotation speed continues to decrease after time t23 even though the engine rotation speed feedback control has been performed for reasons such as a large deceleration of the engine rotation speed.

After that, at time t24, in response to the engine rotation speed becoming smaller than the first predetermined value, in the present embodiment, the motor torque for stopping the engine 2 is set to the first motor generator 4 and the second motor generator. 5. As a result, from time t24 to time t25, the motor torque of the first motor generator 4 and the second motor generator 5 causes the engine rotation speed to drop rapidly, and the engine 2 quickly passes through the resonance region and stops.

On the other hand, in the conventional technology, the engine rotation speed continues to decrease after time t24 as the vehicle speed decreases, as indicated by the dashed line. Therefore, while the engine speed is decreasing to 0, the engine speed stays in the resonance region for a longer time than in the present embodiment.

FIG. 9 shows a case where the engine speed suddenly decreases due to a sudden brake operation by the driver when the shift position is in the D range or the B range and the engine autonomous control (referred to as ISC control in the figure) is not being performed. ing.

In FIG. 9, the accelerator opening becomes 0 at time t31, and the driver performs a sudden braking operation at time t32, increasing the amount of brake depression. As a result, after time t33, the vehicle speed and the engine rotation speed begin to rapidly decrease.

After that, at time t33, in response to the engine rotation speed becoming smaller than the first predetermined value, in the present embodiment, the driving mode is switched from the HEV driving mode to the EV driving mode, and the motor for stopping the engine 2 is switched. Torque is generated in the first motor generator 4 and the second motor generator 5 . As a result, from time t33 to time t34, the motor torque of the first motor generator 4 and the second motor generator 5 causes the engine rotation speed to drop rapidly, and the engine 2 quickly passes through the resonance region and stops.

After that, at time t35, in this embodiment, the driving mode switches from the EV driving mode to the HEV driving mode according to the accelerator opening and the vehicle speed, the engine 2 performs fuel injection and restarts, and the rotational speed of the engine 2 is generated in the first motor-generator 4 and the second motor-generator 5 to increase the .
As a result, the engine rotation speed rapidly increases from time t35 to time t36, and the engine 2 quickly passes through the resonance region.

On the other hand, in the conventional technology, the engine rotation speed continues to decrease toward 0 as the vehicle speed decreases after time t33 as indicated by the dashed line. Therefore, while the engine speed is decreasing to 0, the engine speed stays in the resonance region for a longer time than in the present embodiment.
Further, in the conventional technology, the engine 2 is restarted at time t35 in the HEV running mode, as indicated by the dashed line. Therefore, the engine rotation speed remains in the resonance region for a long time while the engine rotation speed is increasing compared to the present embodiment.

FIG. 10 shows a case where the engine speed suddenly decreases due to a sudden brake operation by the driver when the shift position is in the R range and the engine autonomous control (indicated as ISC control in the figure) is being executed.

In FIG. 10, before time t41, the accelerator opening is 0 and the vehicle speed is constant. Also, the engine rotation speed is a constant rotation speed lower than the resonance region.

After that, at time t41, the engine rotation speed and the vehicle speed start to increase due to the increase in the accelerator opening.

After that, at time t42, in response to the engine rotation speed increasing to the third predetermined value, in the present embodiment, the motor torque for decreasing the engine rotation speed is set to the first motor generator 4 and the second motor generator 5. to occur.

As a result, from time t42 to time t43, the motor torque of the first motor generator 4 and the second motor generator 5 reduces the engine rotation speed to the rotation speed before time t41. Therefore, the engine rotation speed is prevented from entering the resonance region.

On the other hand, in the conventional technology, the engine rotation speed continues to increase as the vehicle speed increases after time t42 as indicated by the dashed line. Therefore, in the process of increasing the engine speed, the engine speed stays in the resonance region for a longer time than in the present embodiment.

Here, when the engine torque of the engine 2 is Teg, the motor torque of the first motor generator 4 is Tmg1, and the motor torque of the second motor generator 5 is Tmg2, the following equation (3) is obtained between these torques: holds.

Tmg1×(k1+1)+Teg×1=Tmg2×k2 (3)
The motor torque Tmg1 of the first motor-generator 4 and the motor torque Tmg2 of the second motor-generator 5 are controlled so that Teg decreases when the engine stops or the engine rotation speed decreases in the equation (3). Further, control is performed so that Teg increases when the engine speed increases.

Here, even if the first motor generator 4 and the second motor generator 5 each generate motor torque so as to satisfy the engine torque expression (3) and the engine torque becomes a negative value, the engine In some cases, the engine speed cannot be quickly reduced due to the inertia of 2.

Therefore, the inertia of the engine 2 must be borne by the first motor generator 4 and the second motor generator 5 . Therefore, the hybrid ECU 32 controls the first motor generator 4 to generate motor torque corresponding to Tmg1+the inertia of the engine, and the second motor generator 5 to generate the motor torque corresponding to Tmg2+the inertia of the engine.

Specifically, in order to correct the inertia of the engine 2, the hybrid ECU 32 controls the first motor generator 4 so as to generate a motor torque represented by the following equation (4). Also, the hybrid ECU 32 controls the second motor generator 5 so as to generate a motor torque represented by the following equation (5).

Note that in equations (4) and (5), the moment of inertia of the engine 2 is Ie, and the angular acceleration of the engine 2 is ω. This ω corresponds to the change rate of the rotation speed when the engine 2 is stopped. Also, in equations (4) and (5), the moment of inertia of the first motor generator 4 is Img1, and the moment of inertia of the second motor generator 5 is Img2.

Tmg1+{(1+k2)/(1+k1+k2)*Ie*ω+Img1*(1+k1)*ω}...(4)
Tmg2+{k1/(1+k1+k2)×Ie×ω−Img2×k2×ω} (5)
That is, the hybrid ECU 32 sets the target motor torque of the first motor-generator 4 to the value represented by the equation (4), and sets the target motor torque of the second motor-generator 5 to the value represented by the equation (5).

Thus, in the above-described embodiment, the hybrid ECU 32 controls the first motor-generator so that the engine 2 is stopped by the motor torque when the engine rotation speed of the engine 2 drops below the first predetermined value. 4 and the second motor generator 5 are controlled.

As a result, when the engine rotation speed drops below the first predetermined value, the first motor generator 4 and the second motor generator 5 are controlled so that the engine 2 is stopped by the motor torque. Therefore, it is possible to prevent the engine 2 from staying in the resonance region and vibrating while the engine rotation speed is decreasing.

Further, in the above-described embodiment, the first predetermined value is a value larger than the upper limit value of the resonance region, which is the region of the engine rotation speed in which the engine 2 resonates.

As a result, the motor torques of the first motor generator 4 and the second motor generator 5 are controlled so as to stop the engine 2 when the engine rotation speed drops below a first predetermined value that is larger than the resonance region. Therefore, it is possible to prevent the engine 2 from vibrating due to the engine rotation speed remaining in the resonance region.

In the above-described embodiment, the hybrid ECU 32 allows the first motor-generator 4 and the second motor-generator 5 not to generate motor torque, and the engine-autonomous ECU 32 to autonomously adjust the engine rotation speed by the engine torque of the engine 2. control can be exercised. Then, the hybrid ECU 32 prohibits the autonomous engine control when the engine rotation speed decreases and becomes equal to or less than a second predetermined value that is larger than the first predetermined value while the engine autonomous control is being executed.

As a result, if the engine speed drops below the second predetermined value during execution of the engine autonomous control, the engine autonomous control is prohibited. Intervention by autonomous control can be prevented. Therefore, the engine rotation speed can be quickly adjusted by the motor torque so that the engine rotation speed does not drop and remain in the resonance region.

Further, in the above-described embodiment, the hybrid ECU 32 controls the first motor generator 4 and the second motor generator 5 so as to increase the engine rotation speed by the motor torque when the engine autonomous control is prohibited.

As a result, when the engine autonomous control is prohibited, the first motor generator 4 and the second motor generator 5 are controlled so that the engine speed is increased by the motor torque. 2 can be prevented from vibrating.

Further, in the above-described embodiment, the vehicle 1 includes the shift position sensor 42 for detecting the shift position, the hybrid ECU 32 detects that the shift position is in the P range or the N range by the shift position sensor 42, and , the engine autonomous control is prohibited when the engine rotation speed drops below a second predetermined value.

As a result, when the shift position is in the P range or the N range, the engine autonomous control is prohibited when the engine rotation speed becomes equal to or lower than the second predetermined value. can be prevented from vibrating.

Further, in the above-described embodiment, the hybrid ECU 32 detects that the shift position is in the R range by the shift position sensor 42, and the engine rotation speed increases to a value smaller than the lower limit value of the resonance region. The first motor-generator 4 and the second motor-generator 5 are controlled so that the engine rotation speed is reduced by the motor torque when it exceeds a certain third predetermined value.

As a result, when the shift position is in the R range, the first motor generator 4 and the second motor generator 4 and the second motor generator are arranged so that the engine rotation speed is decreased by the motor torque when the engine rotation speed increases and becomes equal to or higher than the third predetermined value. 5 is controlled, it is possible to prevent the engine 2 from vibrating due to an increase in the engine rotation speed to the resonance region.

Further, in the above-described embodiment, the hybrid ECU 32 switches to the EV travel mode in which the engine 2 is stopped and the motor torque is used to travel when the engine rotation speed of the engine 2 decreases to the first predetermined value or less. Changing driving mode.

As a result, when the engine rotation speed becomes equal to or lower than the first predetermined value, the mode is changed to the EV running mode, so it is possible to prevent the engine 2 from continuously rotating in the resonance region and vibrating. Further, when the engine 2 needs to be restarted, the engine 2 is restarted in the process of switching from the EV driving mode to the HEV driving mode, so the engine rotation speed rises gently and the engine 2 enters the resonance region. It can be prevented from staying for a long time and vibrating.

That is, in a situation where the engine rotation speed drops sharply in the D range, there is a high possibility that the operation to stop the engine 2 will not be in time and the engine 2 will stop on its own. It is preferable to change from the running mode to the EV running mode.

Also, if the engine 2 is stopped without changing the driving mode from the HEV driving mode to the EV driving mode, the engine 2 continues to be stopped in the N range, but is restarted in the D range. Sometimes. When the engine 2 is restarted in the HEV running mode, the engine rotation speed gently increases, so the time for which the engine rotation speed stays in the resonance region becomes longer.

Therefore, in the present embodiment, by changing to the EV driving mode, when the engine 2 is restarted, it behaves as the starting mode, and the engine speed is lower than when the engine 2 is restarted in the HEV driving mode. Increases speed quickly and shortens the time spent in the resonance area.

Although embodiments of the present invention have been disclosed, it will be apparent that modifications may be made by those skilled in the art without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

1 vehicle (hybrid vehicle)
2 engine 4 first motor generator (motor generator)
5 Second motor generator (motor generator)
7 drive shaft 10 power transmission mechanism 42 shift position sensor (shift position detector)
32 hybrid ECU (control unit)

Claims (3)

A control device for a hybrid vehicle, comprising a control unit that controls a motor generator and an engine, and capable of transmitting motor torque of the motor generator to the engine,
The control unit
Resonance prevention control for reducing the engine rotation speed of the engine by the motor torque in a resonance region where the engine resonates;
an engine autonomous control in which the motor generator autonomously adjusts the engine rotation speed by the engine torque of the engine without generating the motor torque,
having a first predetermined value greater than the upper limit value of the resonance region and a second predetermined value greater than the first predetermined value;
prohibiting the engine autonomous control when the engine rotation speed drops below the second predetermined value;
when the engine rotation speed drops below the first predetermined value due to an increase in the brake depression amount , the vehicle is shifted to an EV travel mode in which the vehicle travels with the motor torque while the engine is stopped; and a control device for a hybrid vehicle, which executes the resonance prevention control. In an HEV driving mode in which the engine torque of the engine and the motor torque are output to drive wheels, the control unit controls the EV driving when the engine rotation speed drops to the first predetermined value or less. 2. The control device for a hybrid vehicle according to claim 1, wherein the mode is shifted to and the resonance prevention control is executed. A shift position detection means for detecting a shift position is provided,
In the control unit, the shift position detection means detects that the shift position is the D range, which is a normal forward position, or the B range, which is an engine braking position, and the engine rotation speed is decreased. 3. The hybrid vehicle according to claim 1 or 2, wherein the vehicle is shifted to the EV driving mode and the resonance prevention control is executed when the vehicle speed becomes equal to or less than the first predetermined value. Control device.

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