JP2018167738A - Vehicle control device - Google Patents

Abstract

To provide a vehicle control device capable of reducing a loss of power transmission in a torque converter during traveling due to motor torque of an electric motor and ensuring engine restartability when switching to traveling due to engine torque of the engine. When the rotational speed ratio of the torque converter is greater than or equal to a predetermined rotational speed ratio during traveling by ISG motor torque (step S2) (YES in step S4), the ECU determines the target according to the engine speed of the engine. The lockup clutch is controlled so as to achieve the degree of engagement (steps S6 and S8). When the engine speed is equal to or higher than the first speed (step S5), the ECU completely engages the lockup clutch (step S6). The ECU slips the lockup clutch (step S8) when the engine speed is equal to or higher than the second speed smaller than the first speed (step S7). [Selection] Figure 2

Description

  The present invention relates to a control device for a vehicle including an engine and an electric motor for traveling.

  As a vehicle control apparatus including an engine and a traveling electric motor, one described in Patent Document 1 is known. The vehicle control apparatus described in Patent Literature 1 starts the engine by transmitting a part of the driving force of the rotating electrical machine to the engine from the EV traveling state in which the driving force is obtained from the rotating electrical machine and traveling.

  Further, the vehicle control device described in Patent Literature 1 slips the lock-up clutch of the torque converter when starting the engine from the EV traveling state, and controls the rotational speed of the rotating electrical machine to the target rotational speed.

  In addition, the vehicle control device estimates the transmission torque transmitted by the slip-up lockup clutch, the transmission input torque determined based on the driving state of the vehicle, and the turbine runner of the torque converter. The target rotational speed of the rotating electrical machine at the time of starting the engine is determined based on the rotational speed. According to the vehicle control device described in Patent Document 1, it is possible to transmit the target torque to the transmission without excess or deficiency.

JP 2010-235089 A

  However, in the vehicle control apparatus described in Patent Document 1, in order to start the engine, the lock-up clutch of the torque converter is slipped when starting the engine from the EV running state. There was a problem of loss of power transmission.

  The present invention has been made paying attention to the above-described problems, and can reduce the loss of power transmission in the torque converter during traveling due to the motor torque of the electric motor, and the engine when switching to traveling due to the engine torque of the engine can be reduced. An object of the present invention is to provide a vehicle control device that can ensure restartability.

  The present invention includes: a drive source having an engine and an electric motor coupled to the engine so as to be able to transmit power to each other; and a transmission to which power is transmitted from the drive source, wherein the transmission is a lock-up clutch. A control unit for controlling the lock-up clutch, wherein the control unit has a predetermined rotational speed ratio of the torque converter during traveling by the motor torque of the electric motor. When the rotation speed ratio is equal to or higher than the rotation speed ratio, the lockup clutch is controlled so as to achieve a target engagement degree corresponding to the engine speed of the engine.

  As described above, according to the present invention, the loss of power transmission in the torque converter can be reduced during traveling by the motor torque of the electric motor, and the restartability of the engine when switching to traveling by the engine torque of the engine can be ensured.

FIG. 1 is a configuration diagram of a vehicle including a control device according to an embodiment of the present invention. FIG. 2 is a flowchart for explaining the operation of the vehicle control apparatus according to the embodiment of the present invention. FIG. 3 is a control table that is referred to during normal control of the lockup clutch in the vehicle control apparatus according to the embodiment of the present invention. FIG. 4 is a timing chart illustrating the transition of the vehicle state when the lockup clutch is engaged in the vehicle control apparatus according to the embodiment of the present invention. FIG. 5 is a timing chart for explaining the transition of the vehicle state when the lockup clutch is slipped in the vehicle control apparatus according to one embodiment of the present invention. FIG. 6 is a timing chart for explaining the transition of the vehicle state when the accelerator opening is a slight opening or the accelerator opening is 0 when the engine is restarted in the vehicle control apparatus according to one embodiment of the present invention. .

  A vehicle control device according to an embodiment of the present invention includes a drive source having an engine and an electric motor coupled to the engine so as to be able to transmit power to each other, a transmission to which power is transmitted from the drive source, A control device for a vehicle having a torque converter with a lock-up clutch and having a control unit that controls the lock-up clutch. When the rotational speed ratio is equal to or higher than the predetermined rotational speed ratio, the lockup clutch is controlled so that the target engagement degree according to the engine rotational speed of the engine is obtained. Thereby, the vehicle control apparatus according to the embodiment of the present invention can reduce the loss of power transmission in the torque converter during traveling due to the motor torque of the electric motor, and restart the engine when switching to traveling due to the engine torque of the engine. Can be secured.

  A vehicle control apparatus according to an embodiment of the present invention will be described below with reference to the drawings. 1 to 6 are diagrams illustrating a vehicle control apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the vehicle 10 includes an engine 20, an ISG (Integrated Starter Generator) 40 as an electric motor, a transmission 30, wheels 12, and an ECU (control unit that comprehensively controls the vehicle 10). Electronic Control Unit) 50.

  The engine 20 is formed with a plurality of cylinders. In this embodiment, the engine 20 is configured to perform a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke for each cylinder. The engine 20 is provided with an intake pipe 22 for introducing air into a combustion chamber (not shown).

  A throttle valve 23 is provided in the intake pipe 22, and the throttle valve 23 adjusts the amount of air passing through the intake pipe 22 (intake amount). The throttle valve 23 is an electronically controlled throttle valve that is opened and closed by a motor (not shown). The throttle valve 23 is electrically connected to the ECU 50, and the throttle valve opening degree is controlled by the ECU 50.

  The engine 20 is provided with an injector 24 for injecting fuel into a combustion chamber via an intake port (not shown) and a spark plug 25 for igniting an air-fuel mixture in the combustion chamber for each cylinder. The injector 24 and the spark plug 25 are electrically connected to the ECU 50. The ECU 50 controls the fuel injection amount and fuel injection timing of the injector 24 and the ignition timing and discharge amount of the spark plug 25.

  The engine 20 is provided with a crank angle sensor 27. The crank angle sensor 27 detects the engine speed based on the rotational position of the crankshaft 20A and transmits a detection signal to the ECU 50.

  The transmission 30 shifts the rotation transmitted from the engine 20 and drives the wheels 12 via the drive shaft 11. The transmission 30 includes an input shaft 30A, a torque converter 30B, a transmission mechanism 30E, and a differential mechanism 30F.

  The torque converter 30B performs torque amplification by converting the rotation transmitted from the engine 20 into torque via the working fluid. The torque converter 30B is provided with a lock-up clutch 30C. When the lockup clutch 30C is released, power is transmitted between the engine 20 and the speed change mechanism 30E via the working fluid. When the lockup clutch 30C is engaged (fastened), power is directly transmitted between the engine 20 and the speed change mechanism 30E via the lockup clutch 30C.

  The power whose torque is amplified in the torque converter 30B is transmitted to the input shaft 30A of the speed change mechanism 30E.

  The transmission mechanism 30E is composed of CVT (Continuously Variable Transmission), and automatically performs a variable transmission steplessly by a set of pulleys around which a metal belt is wound. The ECU 50 controls the change of the gear ratio in the transmission 30 and the engagement or release of the lockup clutch 30C.

  Note that the speed change mechanism 30E may be an automatic transmission (so-called step AT) that performs a step change using a planetary gear mechanism. The differential mechanism 30F is connected to the left and right drive shafts 11, and transmits the power shifted by the speed change mechanism 30E to the left and right drive shafts 11 so as to be differentially rotatable.

  The vehicle 10 includes an accelerator opening sensor 13A. The accelerator opening sensor 13A detects an operation amount of the accelerator pedal 13 (hereinafter simply referred to as “accelerator opening”), and transmits a detection signal to the ECU 50.

  The vehicle 10 includes a brake stroke sensor 14 </ b> A, which detects an operation amount of the brake pedal 14 (hereinafter simply referred to as “brake stroke”) and transmits a detection signal to the ECU 50.

  The vehicle 10 includes a vehicle speed sensor 12 </ b> A. The vehicle speed sensor 12 </ b> A detects a vehicle speed based on the rotational speed of the wheels 12 and transmits a detection signal to the ECU 50. The detection signal of the vehicle speed sensor 12A is used by the ECU 50 or another controller to calculate the slip ratio of each wheel 12 with respect to the vehicle speed.

  The vehicle 10 includes a starter 26. The starter 26 includes a motor (not shown) and a pinion gear fixed to the rotation shaft of the motor. On the other hand, a disc-shaped drive plate is fixed to one end of the crankshaft 20A of the engine 20, and a ring gear is provided on the outer periphery of the drive plate.

  The starter 26 drives the motor in response to a command from the ECU 50, and meshes the pinion gear with the ring gear to rotate the ring gear, thereby starting the engine 20. As described above, the starter 26 starts the engine 20 through the gear mechanism including the pinion gear and the ring gear.

  The ISG 40 is a rotating electrical machine that integrates a starter that starts the engine 20 and a generator that generates electric power. The ISG 40 has a function of a generator that generates power by power from the outside and a function of an electric motor that generates power when power is supplied.

  The ISG 40 is always connected to the engine 20 via a winding transmission mechanism including a pulley 41, a crank pulley 21, and a belt 42, and transmits power to and from the engine 20. More specifically, the ISG 40 includes a rotating shaft 40A, and a pulley 41 is fixed to the rotating shaft 40A. A crank pulley 21 is fixed to the other end portion of the crankshaft 20 </ b> A of the engine 20. A belt 42 is stretched around the crank pulley 21 and the pulley 41. A sprocket and a chain can also be used as the winding transmission mechanism.

  As described above, the engine 20 and the ISG 40 are connected to each other so that power can be transmitted. The engine 20 and the ISG 40 generate torque for the vehicle 10 to travel, and constitute a drive source in the present invention.

  The ISG 40 is driven as an electric motor to rotate the crankshaft 20A and start the engine 20. Here, the vehicle 10 of the present embodiment includes an ISG 40 and a starter 26 as a starting device for the engine 20. The starter 26 is mainly used for cold start of the engine 20 based on the start operation of the driver, and the ISG 40 is mainly used for restart of the engine 20 from the idling stop.

  Here, the ISG 40 can start the engine 20 cold, but the vehicle 10 includes a starter 26 for reliable cold start of the engine 20. For example, the cold start of the engine 20 may be difficult with the power of the ISG 40 due to an increase in the viscosity of the lubricating oil in winter in a cold region, or the ISG 40 may fail. Considering such a case, the vehicle 10 includes both the ISG 40 and the starter 26 as a starting device.

  The power generated by the ISG 40 is transmitted to the wheels 12 via the crankshaft 20A of the engine 20, the transmission 30, and the drive shaft 11.

  The rotation of the wheel 12 is transmitted to the ISG 40 via the drive shaft 11, the transmission 30, and the crankshaft 20 </ b> A of the engine 20, and used for regeneration (power generation) in the ISG 40.

  Therefore, the vehicle 10 can realize not only traveling by the power (engine torque) of the engine 20 (hereinafter also referred to as engine traveling) but also traveling that assists the engine 20 by the power (motor torque) of the ISG 40.

  Furthermore, the vehicle 10 can travel with the power of the ISG 40 (hereinafter also referred to as EV traveling) in a state where the operation of the engine 20 is stopped. Note that during EV traveling, the engine operation is stopped with fuel injection to the engine 20 being non-injected, but the engine 20 is rotated by the ISG 40. Therefore, during EV traveling, the engine operation is stopped, but the engine speed is a speed corresponding to the speed of the ISG 40.

  As described above, the vehicle 10 forms a parallel hybrid system that can travel using at least one of the power of the engine 20 and the power of the ISG 40.

  The vehicle 10 includes a battery 70, and the battery 70 includes a rechargeable secondary battery. The number of cells and the like are set so that the battery 70 generates an output voltage of about 12V.

  The battery 70 is provided with a battery state detection unit 70A. The battery state detection unit 70A detects an inter-terminal voltage, an ambient temperature, and an input / output current of the battery 70, and outputs a detection signal to the ECU 50. The ECU 50 detects the state of charge (SOC) based on the voltage between terminals of the battery 70, the ambient temperature, and the input / output current. The charge state of the battery 70 is managed by the ECU 50.

  Power cables 61 and 64 are connected to the battery 70. The power cable 61 connects the battery 70 and the starter 26, and supplies the power of the battery 70 to the starter 26. The power cable 64 connects the battery 70 and the ISG 40 so that the power of the battery 70 is supplied to the ISG 40 when the ISG 40 is powered, and the power generated by the ISG 40 is supplied to the battery 70 when the ISG 40 is regenerated. It has become.

  The battery 70 also supplies power to other electric loads (not shown). The electric load includes a stability control device that prevents a side slip of the vehicle, an electric power steering control device that electrically assists the operating force of the steering wheel, a headlight, a blower fan, and the like. The electric load includes a wiper, an electric cooling fan that blows cooling air to a radiator (not shown), lamps and meters of an instrument panel (not shown), and a car navigation system.

  The ECU 50 is a computer that includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data, an input port, and an output port. It is composed of units.

  The ROM of this computer unit stores programs for causing the computer unit to function as the ECU 50, along with various constants, various maps, and the like. That is, when the CPU executes a program stored in the ROM using the RAM as a work area, these computer units function as the ECU 50 in this embodiment.

  Various sensors including the crank angle sensor 27, the accelerator opening sensor 13A, the brake stroke sensor 14A, the vehicle speed sensor 12A, and the battery state detection unit 70A are connected to the input port of the ECU 50.

  Various control objects including the throttle valve 23 of the engine 20, the injector 24, the spark plug 25, the ISG 40, the transmission 30, and the starter 26 are connected to the output port of the ECU 50. The ECU 50 controls various control objects based on information obtained from various sensors.

  When a predetermined EV condition for permitting EV traveling is satisfied, ECU 50 causes EV traveling to drive vehicle 10 with the driving torque of ISG 40. The EV condition includes, for example, that the SOC of the battery 70 is larger than a predetermined value, that the accelerator opening is “0”, that there is no start request from the air conditioner or the like to the engine 20, and the like.

  When a predetermined EV prohibition condition for prohibiting EV traveling is satisfied during EV traveling, ECU 50 starts fuel injection to engine 20 and starts engine 20 to cause engine traveling. The EV prohibition conditions include, for example, detection of depression of the accelerator pedal 13 (accelerator on), that the EV traveling time has exceeded a predetermined time, that the SOC of the battery 70 has fallen below a predetermined value, This includes that the temperature has exceeded a predetermined temperature, a request for starting the engine 20 from an air conditioner or the like, and the like.

  The ECU 50 can execute idling stop control that automatically stops the engine 20 when a predetermined automatic stop condition is satisfied and restarts the engine 20 when a predetermined restart condition is satisfied.

  Examples of the predetermined automatic stop condition include that the vehicle speed is lower than a predetermined value, that the brake pedal 14 is depressed, and that the SOC of the battery 70 is higher than the predetermined value. The ECU 50 automatically stops the engine 20 when the aforementioned automatic stop condition is satisfied even during deceleration of the vehicle 10. Further, the predetermined restart condition includes, for example, that the accelerator pedal 13 is stepped on, the brake pedal 14 is not stepped on, and the like.

  When the accelerator pedal 13 is not operated and the depression of the brake pedal 14 is released when the operation of the engine 20 is stopped by the idling stop control, the ECU 50 is based on the SOC of the battery 70. It is determined whether EV traveling is possible.

  When the ECU 50 determines that EV traveling is possible, the ECU 50 causes the vehicle 10 to travel with the power of the ISG 40 while stopping fuel injection to the engine 20.

  That is, in this embodiment, the ECU 50 performs EV creep as one aspect of EV traveling when there is no accelerator operation and brake operation. EV creep is to make the vehicle 10 creep by the power of the ISG 40.

  EV creep realizes creep running in a non-hybrid vehicle by EV running. In the present embodiment, fuel efficiency can be improved by starting the vehicle 10 by EV creep while the operation of the engine 20 is stopped.

  Note that during EV traveling including EV creep, the ECU 50 may perform various controls by referring to the engine speed of the engine 20 that is rotated by the ISG 40.

  The lock-up clutch cooperative control by the ECU 50 of the vehicle 10 configured as described above will be described with reference to the flowchart shown in FIG. This lock-up clutch cooperative control is repeatedly performed with a short predetermined period during the start-up of the system.

  The transition of the vehicle state when the lockup clutch cooperative control is performed will be described with reference to the timing charts shown in FIGS. 4, 5, and 6.

  FIG. 4 is a timing chart when the lockup clutch engagement control (step S6 in FIG. 2) is performed. FIG. 5 is a timing chart when the slip control of the lockup clutch (step S8 in FIG. 2) is performed. FIG. 6 is a timing chart when the accelerator opening is a slight opening or the opening is 0 when the engine is restarted (NO in step S10 of FIG. 2).

  The timing charts of FIGS. 4, 5, and 6 are the accelerator opening, brake stroke, vehicle speed, engine speed (denoted as E / G speed in the figure), torque converter input shaft speed and output shaft speed. , Represents the degree of engagement of the lock-up clutch 30C (denoted as L / U in the figure) and the transition of the fuel injection amount.

  In the initial state (time t0, t10, t20) of FIGS. 4, 5, and 6, the accelerator pedal opening is 0 because the accelerator pedal 13 is not depressed, and the brake pedal 14 is depressed. The stroke is a large value of 0 or more. Further, since the brake pedal 14 is depressed, the vehicle speed is zero. Further, the engine speed is 0, the input shaft speed and the output shaft speed of the torque converter are 0, the degree of engagement of the lockup clutch 30C is 0, and the fuel injection amount is 0.

  In FIG. 2, the ECU 50 determines whether or not the EV creep condition is satisfied (step S1). If the EV creep condition is not satisfied, the ECU 20 restarts the engine 20 by the driving force of the starter 26 or the ISG 40 (step S1). S15), normal control is performed on the lock-up clutch 30C (step S16).

  In the normal control in step S16, the ECU 50 refers to a lockup control table (denoted as an L / U control table in the drawing) shown in FIG. 3 and determines a condition for engaging the lockup clutch 30C. In the lock-up control table, the vehicle speed at which the lock-up clutch 30C is engaged is determined according to the accelerator opening. The ECU 50 engages the lockup clutch 30C when the vehicle speed corresponding to the accelerator opening is reached.

  When the EV creep condition is satisfied in step S1, the ECU 50 drives the ISG 40 (step S2). The EV creep condition is satisfied at time t1 in FIG. 4, time t11 in FIG. 5, and time t21 in FIG. 6, and the ISG 40 generates a positive motor torque, so that the vehicle 10 starts and the vehicle speed increases. .

  After step S2, ECU 50 calculates rotation speed ratio e of torque converter 30B (step S3). The rotational speed ratio e is a value obtained by dividing the output shaft rotational speed of the torque converter 30B by the input shaft rotational speed.

  Next, the ECU 50 determines whether or not the rotational speed ratio e is greater than or equal to a predetermined rotational speed ratio E (step S4). Here, the predetermined rotational speed ratio E is the rotational speed ratio of the clutch point in the torque converter characteristics. The torque converter characteristic represents the correlation of the pump capacity coefficient, the torque ratio, and the transmission efficiency with respect to the rotational speed ratio e. In the torque converter characteristic, in the converter range (converter range) in which the rotational speed ratio e is smaller than the predetermined rotational speed ratio E (clutch point), the torque ratio is 1 or more, and torque amplification is performed. On the other hand, in the joint range (coupling range) in which the rotational speed ratio e is larger than the predetermined rotational speed ratio E (clutch point), the torque ratio is constant at 1 and torque amplification is not performed. The transmission efficiency is low in the converter range and high in the joint range.

  When the rotational speed ratio e is greater than or equal to the predetermined rotational speed ratio E in step S4, that is, when the torque converter 30B is in the joint range, the ECU 50 determines whether or not the engine rotational speed is greater than or equal to the first rotational speed. (Step S5).

  If the rotational speed ratio e is less than the predetermined rotational speed ratio E in step S4, that is, if the torque converter 30B is in the converter range, the ECU 50 proceeds to step S9.

  If the engine speed is greater than or equal to the first speed in step S5, the ECU 50 performs engagement control of the lockup clutch 30C (step S6), and proceeds to step S9. The engagement control in step S6 is control for bringing the lock-up clutch 30C into an engaged state.

  Thus, when the rotational speed ratio e is greater than or equal to the predetermined rotational speed ratio E in step S4 and the engine rotational speed is greater than or equal to the first rotational speed in step S5, the lockup clutch 30C is engaged in step S6. When the rotational speed ratio e is less than the predetermined rotational speed ratio E in step S4, the lockup clutch 30C is not engaged and torque amplification is performed in the torque converter 30B.

  In step S5, when the engine speed is less than the first speed due to a large traveling load of the vehicle 10, the ECU 50 determines whether or not the engine speed is equal to or higher than the second speed. (Step S7). Here, the second rotational speed is a rotational speed smaller than the first rotational speed. The second rotation speed is higher than the rotation speed at which the engine 20 can be returned (restarted) to self-sustained rotation only by fuel injection. The number of rotations at which the engine 20 can be returned (restarted) to the self-sustaining rotation only by fuel injection is a number of rotations greater than the idling rotation number.

  If the engine speed is greater than or equal to the second speed in step S7, the ECU 50 performs slip control of the lockup clutch 30C (step S8) and proceeds to step S9. The slip control in step S8 is control that causes the lock-up clutch 30C to slip in a half-engaged state (half-engaged state).

  If the engine speed is less than the second speed in step S7, the ECU 50 proceeds to step S9 without slipping the lockup clutch 30C.

  At time t2 in FIG. 4, since the rotational speed ratio e is equal to or higher than the predetermined rotational speed ratio E and the engine rotational speed is equal to or higher than the first rotational speed, step S6 is performed and the lockup clutch 30C is released ( Control is performed from the disconnected state to the fastened (connected) state. For this reason, the input shaft rotation speed and the output shaft rotation speed of the torque converter 30B start to coincide with each other.

  At time t12 in FIG. 5, since the rotational speed ratio e is equal to or greater than the predetermined rotational speed ratio E and the engine rotational speed is less than the first rotational speed, step S8 is performed and the lockup clutch 30C slips. It is controlled as follows. For this reason, the input shaft rotation speed and the output shaft rotation speed of the torque converter 30B do not match.

  In the period from time t12 to time t13, the torque converter 30B is slip-controlled so that the output shaft rotational speed is maintained at a certain level or more. This is because when the torque converter 30B is completely fastened, there is a possibility that the engine 20 cannot be restarted by using a method of returning the engine 20 to the self-rotation by restarting fuel injection.

  In step S9, the ECU 50 determines whether or not an engine restart condition is satisfied. If the engine restart condition is not satisfied, the ECU 50 returns to step S3. If the engine restart condition is satisfied, the ECU 50 determines whether or not the accelerator opening is equal to or greater than a predetermined opening (step S10).

  If the accelerator opening is greater than or equal to the predetermined opening in step S10, the ECU 50 releases (releases) the engagement of the lockup clutch 30C.

  When the accelerator opening is less than the predetermined opening in step S10, the ECU 50 maintains or slips the lockup clutch 30C (step S12).

  Next, the ECU 50 changes the motor torque of the ISG 40, restarts the engine 20 (step S13), and performs normal control on the lockup clutch 30C (step S14). The normal control in step S14 is the same as the normal control in step S16.

  At time t3 in FIG. 4 and time t13 in FIG. 5, when the accelerator pedal 13 is depressed and the accelerator opening increases to an opening greater than or equal to a predetermined opening, the restart condition of the engine 20 is satisfied, and the lockup clutch The fastening of 30C is released (released), and the rotational speed of the ISG 40 is reduced. As a result, the ISG 40 is prevented from rotating at high speed with no load, and the ISG 40 is protected. At time t4 in FIG. 4 and time t14 in FIG. 5, the engine 20 is restarted by restarting fuel injection, and the vehicle speed is increased by engine torque.

  At time t23 in FIG. 6, the restart condition of the engine 20 is established due to factors other than the operation of the accelerator pedal 13. FIG. 6 shows a case where the lock-up clutch 30C is maintained in the engaged state and a case where the lock-up clutch 30C is slipped accordingly.

  As described above, in this embodiment, when the rotational speed ratio e of the torque converter 30B is equal to or higher than the predetermined rotational speed ratio E during traveling by the motor torque of the ISG 40, the ECU 50 sets the target according to the engine speed of the engine 20. The lock-up clutch 30C is controlled so as to achieve the degree of engagement.

  Accordingly, when the rotational speed ratio e of the torque converter 30B is equal to or greater than the predetermined rotational speed ratio E during traveling by the motor torque of the ISG 40, the lockup clutch 30C has a target engagement degree corresponding to the engine rotational speed of the engine 20. To be controlled. For this reason, the loss of power transmission in torque converter 30B can be reduced. Further, when the engine 20 is restarted, the motor torque of the ISG 40 can be transmitted to the engine 20 efficiently, so that the restartability of the engine 20 can be ensured.

  As a result, it is possible to reduce power transmission loss in the torque converter 30B during traveling by the motor torque of the ISG 40, and to ensure restartability of the engine 20 when switching to traveling by the engine torque of the engine 20.

  In the present embodiment, the ECU 50 completely engages the lockup clutch 30C when the engine speed is equal to or higher than the first speed.

  In this embodiment, the ECU 50 causes the lockup clutch 30C to slip when the engine speed is equal to or higher than the second speed smaller than the first speed.

  In this embodiment, the ECU 50 opens the lockup clutch 30C when the engine speed is less than the second speed.

  In this way, during EV travel, the ISG 40 is adjusted by adjusting the degree of engagement of the lock-up clutch 30C so as not to fall below the number of revolutions at which the engine 20 can be returned to self-sustained rotation (restart) only by fuel injection. It becomes easy to switch from the EV traveling by the engine to the traveling by the engine 20.

  In this embodiment, when the ECU 50 switches from traveling by the motor torque of the ISG 40 to traveling by the motor torque and the engine 20 of the engine 20, the ECU 50 determines the degree of engagement of the lockup clutch 30C based on the accelerator opening of the accelerator pedal 13. The engine 20 is restarted by restarting the fuel injection.

  In this embodiment, the ECU 50 opens the lock-up clutch 30C when the accelerator opening is equal to or larger than the predetermined accelerator opening, and sets the lock-up clutch 30C in the engaged state when the accelerator opening is less than the predetermined accelerator opening. Maintain or slip lockup clutch 30C.

  In this way, when the engine 20 is restarted by depressing the accelerator pedal 13, the acceleration performance can be ensured by controlling the lockup clutch 30C so that torque amplification in the torque converter 30B is possible. .

Further, when the accelerator pedal 13 is depressed in a small amount and the acceleration request is small, the torque converter that is a fluid clutch from the wheel 12 that is a driving wheel is maintained by maintaining the lock-up clutch 30C in the engaged state or performing slip control. Since power can be transmitted to the engine 20 via 30B, it is possible to prevent a drop in engine speed.
While embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

10 Vehicle 13 Accelerator pedal 20 Engine (drive source)
30 Transmission 30B Torque converter 30C Lock-up clutch 40 ISG (electric motor, drive source)
50 ECU (control unit)

Claims (6)

A drive source having an engine and an electric motor coupled to the engine so as to transmit power to each other;
A transmission to which power is transmitted from the drive source,
The transmission is a vehicle control device having a torque converter with a lock-up clutch,
A control unit for controlling the lock-up clutch;
The controller is
When the rotational speed ratio of the torque converter is greater than or equal to a predetermined rotational speed ratio during traveling by the motor torque of the electric motor, the lockup clutch is controlled so that a target engagement degree according to the engine speed of the engine is obtained. A control apparatus for a vehicle. The controller is
2. The vehicle control device according to claim 1, wherein when the engine speed is equal to or higher than the first speed, the lockup clutch is completely engaged. The controller is
3. The vehicle control device according to claim 2, wherein the lock-up clutch is slipped when the engine speed is equal to or higher than a second speed smaller than the first speed. 4. The controller is
4. The vehicle control device according to claim 3, wherein when the engine speed is less than the second speed, the lockup clutch is released. The controller is
When switching from running by the motor torque of the electric motor to running by the motor torque and engine torque of the engine,
Change the degree of engagement of the lockup clutch based on the accelerator opening of the accelerator pedal,
The vehicle control device according to any one of claims 1 to 4, wherein the engine is restarted by resuming fuel injection. The controller is
If the accelerator opening is greater than or equal to a predetermined accelerator opening, release the lock-up clutch,
6. The vehicle control device according to claim 5, wherein when the accelerator opening is less than a predetermined accelerator opening, the locked state of the lock-up clutch is maintained or the lock-up clutch is slipped.

Images