JP6237287B2 - Drive control apparatus for hybrid vehicle - Google Patents

Description

  The present invention relates to a drive control device for a hybrid vehicle, and more particularly to a drive control device for a hybrid vehicle that transmits power generated by an engine and a motor generator to drive wheels via a power transmission mechanism.

  In a hybrid vehicle that uses an engine and a motor generator as drive sources and the engine and drive wheels cannot be separated from each other, if a shift position corresponding to a non-drive range such as a neutral range is selected, it is transmitted to the drive wheels. In order to make the torque to be zero, it is necessary to set the output torque of the motor generator to zero so that the torque generated by the engine is not transmitted to the drive wheels. A mode in which the engine is driven without transmitting torque to the drive wheels in this way is hereinafter referred to as an ISC (Idle Speed Control) mode.

  For example, in Patent Document 1, control is performed so that the driving force of a driving source composed of an engine and a motor generator becomes a target driving force, and the motor generator is fed back so as to eliminate the deviation between the target engine rotation speed and the actual engine rotation speed. In the hybrid vehicle to be controlled, when it is determined that the shift position is the parking range or the neutral range, and the low vehicle speed state in which the vehicle speed is equal to or lower than the set vehicle speed continues for a certain time or more, the vehicle is determined to be in the idle state There has been proposed one that shifts the operation mode to the ISC mode and restricts the feedback control.

Japanese Patent No. 5246429

  However, the technique proposed in Patent Document 1 has a problem that the engine rotational speed may temporarily increase when the engine is shifted to the ISC mode with a relatively high engine torque. .

  Accordingly, the present invention has been made to solve such a problem, and is a hybrid vehicle control device capable of suppressing a temporary increase in the rotational speed of the engine when the mode is shifted to the ISC mode. The purpose is to provide.

A first aspect of the present invention is a hybrid vehicle drive in which power generated by an engine and a motor generator is transmitted to a drive shaft via a power transmission mechanism, and the engine and the drive shaft cannot be separated. A control device, a feedback control unit for performing feedback control for controlling the motor generator so that a rotational speed of the engine becomes a target rotational speed, an engine torque setting unit for setting a torque to be generated by the engine, The feedback control unit has an ISC mode for driving the engine without transmitting torque to the drive shaft as an operation mode, and has received an ISC mode shift request for shifting the operation mode to the ISC mode. In this case, a torque less than a specified torque is set in the engine torque setting unit. Allowed, on condition that the engine torque generated by the engine is determined to be less than the specified torque, it is characterized in that to stop the feedback control.

A second aspect of the present invention further includes a shift position sensor that detects a shift position, and the ISC mode shift request is that the shift position detected by the shift position sensor is switched to a non-driving range. May be determined .

As a third aspect of the present invention, whether or not the engine torque generated by the engine is less than a specified torque is determined based on the value of the engine torque detected based on the output torque of the motor generator, or the engine The determination may be made according to any of the elapsed time since the torque setting unit set a torque less than the specified torque .

  As described above, in the first aspect, the engine torque generated by the engine decreases below the specified torque, and the output torque of the motor generator is sufficiently decreased. Therefore, it is possible to suppress a temporary increase in the rotational speed of the engine.

In the second aspect, the ISC mode transition request can be detected.

  In the third aspect, it is possible to detect that the engine torque generated by the engine is sufficiently reduced without detecting the engine torque generated by the engine.

FIG. 1 is a configuration diagram showing a main part of a hybrid vehicle equipped with a drive control apparatus according to an embodiment of the present invention. FIG. 2 is a timing chart when the operation mode of the vehicle is shifted from the MG rotation feedback mode to the ISC mode by the conventional control. FIG. 3 is a flowchart showing the driving force limiting operation by the drive control apparatus according to the embodiment of the present invention. FIG. 4 is a timing chart when the operation mode of the vehicle is shifted from the MG rotation feedback mode to the ISC mode by the drive control device according to the embodiment of the present 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”) 100 equipped with a drive control apparatus according to an embodiment of the present invention includes a drive mechanism 1 and an ECU (Electronic Control Unit) 32. ing.

  The drive mechanism 1 includes an internal combustion engine type engine 2, an output shaft 3 of the engine 2, a first motor generator 4 and a second motor generator 5 that generate driving power from driving power while generating driving power. The drive shaft 7 connected to the drive wheel 6 of the vehicle 100 and the first planetary gear mechanism 8 and the second planetary gear mechanism 9 constituting the power transmission mechanism 10 are configured.

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

  The output shaft 3 is provided with a one-way clutch 40. When the output shaft 3 of the engine 2 rotates in the reverse direction, the one-way clutch 40 uses this reverse rotation torque as the first planetary gear mechanism 8 and the second planetary gear. It is configured not to be transmitted to the 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. The 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 coil of the stator 15, a rotating magnetic field is formed by the stator 15, and the rotating magnetic field is permanently embedded in the rotor 14. By pulling the magnet, 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 a driving force for driving the vehicle 100.

  Further, when the rotor 14 rotates around the rotor shaft 13, a rotating magnetic field is formed by the permanent magnet embedded in the rotor 14, and an induced current flows through the three-phase coil of the stator 15 by this rotating magnetic field. Electric power is generated at both ends. In other words, the first motor generator 4 also functions as a generator and can generate electric power for charging the battery 21.

  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. The 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 coil of the stator 18, a rotating magnetic field is formed by the stator 18, and the rotating magnetic field is permanently embedded in the rotor 17. By pulling the magnet, 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 a driving force for driving the vehicle 100.

  Further, when the rotor 17 rotates around the rotor shaft 16, a rotating magnetic field is formed by the permanent magnet embedded in the rotor 17, and an induction current flows through the three-phase coil of the stator 18 by this rotating magnetic field. Electric power is generated at both ends. In other words, the second motor generator 5 also functions as a generator and can generate electric power for charging the battery 21.

  The first planetary gear mechanism 8 includes a sun gear 22, a plurality of planetary gears 23 that mesh with the sun gear 22, and a ring gear 25 that meshes with the plurality of planetary gears 23. Yes.

  The second planetary gear mechanism 9 includes a sun gear 26, a plurality of planetary gears 27 that mesh with the sun gear 26, and a ring gear 29 that meshes with the plurality of planetary gears 27. Yes.

  The sun gear 22 of the first planetary gear mechanism 8 is connected to the 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 the output shaft 3 of the engine 2 via the one-way clutch 40 so as to rotate together.

  The ring gear 25 of the first planetary gear mechanism 8 is connected to the planetary gear 27 of the second planetary gear mechanism 9 via the planetary carrier 28 so as to be able to revolve around the rotor shaft 13. The ring gear 25 of the first planetary gear mechanism 8 is formed to rotate the drive shaft 7 via an output transmission mechanism 31 including a differential gear 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. As described above, the power transmission mechanism 10 is configured to exchange driving force among the engine 2, the first motor generator 4, the second motor generator 5, and the drive shaft 7. For example, the power transmission mechanism 10 transmits the power generated by the engine 2, the first motor generator 4, and the second motor generator 5 to the drive shaft 7.

  The ECU 32 includes a computer unit that includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), a flash memory, an input port, and an output port.

  A program for causing the computer unit to function as the ECU 32 is stored in the ROM of the ECU 32 together with various control constants and various maps. That is, in the ECU 32, the computer unit functions as the ECU 32 when the CPU executes a program stored in the ROM.

  The input port of the ECU 32 includes an accelerator opening sensor 41 that detects an accelerator pedal opening (hereinafter simply referred to as “accelerator opening”) Acc, a vehicle speed sensor 42 that detects a vehicle speed V, and an engine speed of the engine 2. An engine rotation speed sensor 43 that detects Ne (hereinafter simply referred to as “engine rotation speed”) and a shift position sensor 44 that detects the shift position Sp are connected.

  In addition to the first inverter 19 and the second inverter 20, an injector 45 that injects fuel into the combustion chamber of the engine 2 and a throttle valve that adjusts the intake air amount of the engine 2 are provided at the output port of the ECU 32. Is connected to a throttle valve actuator 46 for adjusting the opening degree.

  In the present embodiment, the ECU 32 controls the EV mode in which the vehicle 100 is driven by at least one of the first motor generator 4 and the second motor generator 5, and the first motor generator 4 and the first motor generator 4 while driving the vehicle 100 by the engine 2. One of a plurality of operation modes including an MG rotation feedback mode for adjusting the engine rotation speed at least one of the two motor generators 5 and an ISC mode for driving the engine 2 without transmitting torque to the drive wheels 7. The vehicle 100 is controlled in the operation mode.

  The ECU 32 constitutes a feedback control unit 50 that performs feedback control for controlling at least one of the first motor generator 4 and the second motor generator 5 so that the rotational speed of the engine 2 becomes the target rotational speed.

  Specifically, the ECU 32 determines a driving force required for the vehicle 100 (hereinafter simply referred to as “required driving force”) Freq. Specifically, the ROM of the ECU 32 stores a required driving force map in which the required driving force Freq is associated with the accelerator opening Acc and the vehicle speed V for each shift position Sp.

  The ECU 32 refers to the required driving force map corresponding to the shift position Sp detected by the shift position sensor 44, and determines the accelerator opening Acc detected by the accelerator opening sensor 41 and the vehicle speed V detected by the vehicle speed sensor 42. The required driving force Freq is determined based on the above.

  Further, the ECU 32 determines a power required for the vehicle 100 (hereinafter simply referred to as “vehicle required power”) Preq. In the present embodiment, the ECU 32 calculates the vehicle required power Preq by multiplying the required driving force Freq, the vehicle speed V, and a predetermined constant. Here, the predetermined constant is a constant corresponding to the gear ratio of the output transmission mechanism 31.

  Further, the ECU 32 is configured to calculate a target engine power Pe targeted by the engine 2. In the present embodiment, the ECU 32 calculates the target engine power Pe by adding the power required for charging the battery 21 and the auxiliary machine to the vehicle required power Preq.

  The ROM of the ECU 32 stores an operation map in which the engine 2 is driven with optimum fuel consumption. The operation map defines an optimum fuel consumption line that represents the relationship between the target engine rotation speed and the target engine torque for driving the engine 2 with the optimum fuel consumption.

  In the MG rotation feedback mode, the ECU 32 sets the first inverter so that the target engine rotation speed corresponding to the intersection of the optimum fuel consumption line and the equal output line representing the target engine power Pe on the operation map matches the engine rotation speed Ne. By controlling 19 and the second inverter 20, feedback control for adjusting the output torque of the first motor generator 4 and the second motor generator 5 is executed.

  Further, the ECU 32 controls the first inverter 19 and the second inverter 20 in the ISC mode, thereby reducing the output torque of the first motor generator 4 and the second motor generator 5 to 0 and optimal on the operation map. For example, the throttle valve actuator 46 is controlled so that the target engine rotational speed corresponding to the intersection of the fuel consumption line and the iso-output line representing the target engine power Pe and the engine rotational speed Ne coincide with each other at the target idle rotational speed during idle operation. By doing so, the intake air amount of the engine 2 is controlled.

  In the present embodiment, the ECU 32 changes the operation mode of the vehicle 100 to the MG rotation feedback on condition that there is an ISC mode transition request that requests the operation mode of the vehicle 100 to shift from the MG rotation feedback mode to the ISC mode. The mode is shifted to the ISC mode.

  Here, the ECU 32 determines that an ISC mode transition request has been made on the condition that the shift position Sp has been switched to a non-driving range such as a neutral range and a parking range in which the vehicle 100 is not driven. . The ECU 32 may determine that the ISC mode shift request has been made on the condition that the vehicle speed V is lower than a predetermined speed for a predetermined time.

  Further, the ECU 32 generates torque to be generated by the engine 2 so that the target engine rotational speed corresponding to the intersection of the optimum fuel consumption line and the equal output line representing the target engine power Pe on the operation map matches the engine rotational speed Ne. An engine torque setting unit 51 to be set is configured.

  Specifically, ECU 32 sets the instruction torque of engine 2 to 0 on the condition that the operation mode of vehicle 100 is shifted from the MG rotation feedback mode to the ISC mode, and the engine 2 can operate independently. To do. Thus, the ECU 32 sets the torque to be generated by the engine 2 so that the engine torque Te generated by the engine 2 is less than the specified torque.

  Here, the prescribed torque is an adaptive value that is determined in advance below the target idle torque when the engine 2 is in idle operation.

  Further, the ECU 32 stops the feedback control on condition that the operation mode of the vehicle 100 is shifted from the MG rotation feedback mode to the ISC mode.

  FIG. 2 shows an engine rotation speed Ne, an engine torque Te, and an output torque of the first motor generator 4 according to conventional control for shifting the operation mode of the vehicle 100 from the MG rotation feedback mode to the ISC mode when the ISC mode shift request is made. (Denoted as “MG1 torque” in the figure) is shown on the time axis.

  As shown in FIG. 2, when there is a request to shift to the ISC mode at time t1 when the engine torque Te is not sufficiently reduced, if the operation mode of the vehicle 100 is shifted to the ISC mode, the first motor generator 4 Since the output torque is controlled to 0, the engine rotation speed Ne may increase temporarily.

  Therefore, when there is a request to shift to the ISC mode, the ECU 32 shifts the operation mode of the vehicle 100 from the MG rotation feedback mode to the ISC mode on condition that the engine torque Te is less than the specified torque. ing.

  That is, the ECU 32 stops the feedback control on condition that the engine torque Te is less than the specified torque in a state where the shift position Sp detected by the shift position sensor 44 corresponds to the non-driving range. ing.

  The ECU 32 constitutes an engine torque detector 52 that detects the engine torque Te. Here, the number of teeth of the sun gear 22 of the first planetary gear mechanism 8 is ZS1, the number of teeth of the ring gear 25 of the first planetary gear mechanism 8 is ZR1, and the number of teeth of the sun gear 26 of the second planetary gear mechanism 9 is ZS2. The number of teeth of the ring gear 29 of the second planetary gear mechanism 9 is ZR2.

  When k1 = ZR1 / ZS1, k2 = ZR2 / ZS2, the output torque of the first motor generator 4 is Tmg1, and the output torque of the second motor generator 5 is Tmg2, the engine torque Te is expressed by the following formula ( It can be obtained by calculating 1).

  Te = − (1 + k1) Tmg1 + k2 × Tmg2 (1)

  That is, the ECU 32 detects the engine torque Te by calculating the expression (1). The output torque Tmg1 of the first motor generator 4 and the output torque Tmg2 of the second motor generator 5 are maps representing the relationship between the value of the current flowing through the three-phase coil of each motor generator and the torque of each motor generator. Can be identified by referring to.

  The driving force limiting operation by the drive control apparatus according to the embodiment of the present invention configured as described above will be described with reference to FIG. The driving force limiting operation described below is repeatedly executed when the operation mode of the vehicle 100 is in the MG rotation feedback mode.

  First, the ECU 32 determines whether or not an ISC mode transition request has been made (step S1). Here, when it is determined that there is no ISC mode transition request, the ECU 32 ends the driving force limiting operation.

  On the other hand, when determining that the ISC mode transition request has been made, the ECU 32 sets the instruction torque of the engine 2 to 0 (step S2). Next, the ECU 32 determines whether or not the engine torque Te is less than the specified torque (step S3).

  When determining that the engine torque Te is not less than the specified torque, the ECU 32 returns the driving force limiting operation to step S3. On the other hand, when determining that the engine torque Te is less than the specified torque, the ECU 32 shifts the operation mode of the vehicle 100 to the ISC mode (step S4) and ends the driving force limiting operation.

  FIG. 4 shows the engine rotation speed Ne, the engine torque Te, and the output torque of the first motor generator 4 (“MG1 torque in the figure”) when the ISC mode shift request is issued by the drive control device according to the embodiment of the present invention. ")" On the time axis.

  As shown in FIG. 4, in the present embodiment, when there is a request to shift to the ISC mode at time t11 when the engine torque Te has not sufficiently decreased, the engine torque Te decreases to less than the specified torque, Since the operation mode of the vehicle 100 is shifted from the MG rotation feedback mode to the ISC mode at time t12 when the output torque of the motor generator 4 approaches 0, the engine rotation speed Ne is prevented from temporarily increasing.

  In the present embodiment, the ECU 32 constitutes an engine torque detector 52 that detects the engine torque Te, detects the engine torque Te by calculating the equation (1), and the detected engine torque Te is defined. It has been described that it is determined whether or not the torque is less than the torque.

  Instead, the ECU 32 determines that the engine torque Te is less than the specified torque on the condition that the specified time has elapsed since the engine torque Te was set to 0 in response to the ISC mode transition request. You may do it.

  Although the embodiments of the present invention have been disclosed above, it is obvious that those skilled in the art can make modifications without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the claims recited in the claims.

2 Engine 4 First motor generator (motor generator)
5 Second motor generator (motor generator)
10 Power transmission mechanism 32 ECU
44 shift position sensor 50 feedback control unit 51 engine torque setting unit 52 engine torque detection unit 100 vehicle (hybrid vehicle)

Claims (3)

A drive control device for a hybrid vehicle that transmits power generated by an engine and a motor generator to a drive shaft via a power transmission mechanism and cannot separate the engine and the drive shaft ,
A feedback control unit that executes feedback control for controlling the motor generator so that the rotational speed of the engine becomes a target rotational speed;
An engine torque setting unit for setting torque to be generated by the engine ,
The feedback control unit has an ISC mode for driving the engine without transmitting torque to the drive shaft as an operation mode, and when an ISC mode shift request for shifting the operation mode to the ISC mode is received. A drive control device that causes the engine torque setting unit to set a torque less than a specified torque and stops the feedback control on condition that the engine torque generated by the engine is determined to be less than the specified torque. A shift position sensor for detecting the shift position;
2. The drive control device according to claim 1, wherein the ISC mode transition request is determined on the condition that the shift position detected by the shift position sensor is switched to a non-drive range. . Whether the engine torque generated by the engine is less than a specified torque is determined based on the value of the engine torque detected based on the output torque of the motor generator, or the torque less than the specified torque by the engine torque setting unit. The drive control device according to claim 1, wherein the drive control device is determined according to any of the elapsed time since the setting.

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