JP2017171063A - Vehicular control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a deterioration in fuel economy in starting an engine due to a power transmission loss in a torque converter.SOLUTION: A vehicular control apparatus includes: an input clutch, disposed in a power transmission path connecting an engine and a drive wheel, for transmitting power of the engine to the drive wheel; a lock-up clutch, disposed between the engine and the input clutch, for transmitting the power of the engine to the input clutch; a first control part for executing first start control to engage the input clutch when starting the engine on the basis of required drive power and engage the lock-up clutch after engaging the input clutch; and a second control part for executing second start control to engage the lock-up clutch when starting the engine on the basis of the required drive power and engage the input clutch after engaging the lock-up clutch. Further, in a case where the required drive power exceeds a first threshold, the first start control is executed, whereas in a case where the required drive power is less than the first threshold, the second start control is executed.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a control device for a vehicle.

  A vehicle is known that temporarily stops an engine when a predetermined condition is satisfied. For example, when the brake pedal is depressed to stop the vehicle, the engine is temporarily stopped, and when the brake pedal is released, the engine is started (restarted) (generally called “idling stop function”). .) Is widely used. In some vehicles, the engine is temporarily stopped when the vehicle speed falls below a predetermined speed during traveling, and then the engine is started (restarted) when the accelerator pedal is depressed or the brake pedal is released.

  Moreover, regardless of whether or not it has a function of temporarily stopping the engine, many conventional vehicles are equipped with a torque converter having a lock-up clutch. The torque converter has a pump impeller connected to the engine side and a turbine runner connected to the transmission side. The lock-up clutch increases the power transmission efficiency by directly connecting the pump impeller and the turbine runner to improve fuel efficiency (Patent Document 1).

Japanese Patent No. 5528129

  However, a vehicle equipped with a torque converter having a lock-up clutch and having a function of temporarily stopping the engine has the following problems. That is, in such a vehicle, the lock-up clutch is released when the engine is started in order to avoid a shock when the engine is started. In other words, the engine is started with the lock-up clutch released. For this reason, a fuel consumption deteriorates by the power transmission loss of a torque converter. Further, the engine speed may increase excessively when the engine is started due to the slip of the torque converter.

  An object of the present invention is to suppress deterioration in fuel consumption at the time of engine start due to power transmission loss of a torque converter.

  The vehicle control device of the present invention is a vehicle control device including an engine that is started based on a required driving force. The vehicle control device is provided in a power transmission path that connects the engine and drive wheels, and is provided between an input clutch that transmits the power of the engine to the drive wheels, and the engine and the input clutch. A lock-up clutch that transmits the power of the engine to the input clutch, and when the engine is started based on the required driving force, the input clutch is engaged, and after the input clutch is engaged, the lock-up clutch A first control unit that executes a first start control for fastening the engine, and the input clutch after the lockup clutch is fastened and the lockup clutch is fastened when the engine is started based on the required driving force. And a second control unit that executes a second start control for fastening. Then, when the required driving force exceeds the first threshold value, the first start control is executed, whereas when the required driving force is lower than the first threshold value, the second start control is executed.

  According to the present invention, fuel consumption deterioration at the time of engine start due to power transmission loss of the torque converter is suppressed.

It is the schematic which shows the control apparatus for vehicles which is an example of embodiment of this invention. It is a control map which shows the example of a setting of the execution area | region of 2nd start control. It is a flowchart which shows an example of the setting procedure of start control. It is a timing chart which shows an example of the execution situation of the 2nd starting control. It is a timing chart which shows an example of the execution situation of the 1st start control.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a vehicle control device 10 which is an example of an embodiment of the present invention. As shown in FIG. 1, the vehicle control device 10 according to the present embodiment includes a power unit 13 including an engine 11 and a motor generator (electric motor 12) as power sources. Further, the power unit 13 has a speed change mechanism 16. The transmission mechanism 16 is a continuously variable transmission mechanism and includes a primary pulley 14 and a secondary pulley 15. The primary pulley 14 is connected to the engine 11 via an input clutch 17 and a torque converter 18 including a lock-up clutch 46, and is connected to the electric motor 12 via a motor shaft 19. On the other hand, wheels (drive wheels) 22 are connected to the secondary pulley 15 via an output shaft 20 and a differential mechanism 21. As described above, the engine 11 and the electric motor 12 are connected via the power transmission path 31 including the torque converter 18, the input clutch 17, the primary pulley 14, and the like. The secondary pulley 15, the output shaft 20, the differential mechanism 21 and the like are connected via a power transmission path 32. In the following description, the power transmission path 31 may be referred to as “first power transmission path 31”, and the power transmission path 32 may be referred to as “second power transmission path 32”. The first power transmission path 31 and the second power transmission path may be collectively referred to as “power transmission path”.

  As described above, at least the torque converter 18, the input clutch 17, and the continuously variable transmission mechanism 16 (primary pulley 14) are provided in the first power transmission path 31, and the input clutch 17 is connected to the torque converter 18 (lock-up). The clutch 46) and the continuously variable transmission mechanism 16 are provided. The electric motor 12 is connected to the power transmission path, more specifically, to the first power transmission path 31 on the drive wheel side of the input clutch 17. On the other hand, the second power transmission path 32 is provided with a continuously variable transmission mechanism 16 (secondary pulley 15), an output shaft 20, and a differential mechanism 21.

  In other words, the first power transmission path 31 and the second power transmission path 32 are connected via the continuously variable transmission mechanism 16, and the rotation shaft (primary shaft) of the primary pulley 14 is the input of the continuously variable transmission mechanism 16. The rotation shaft (secondary shaft) of the secondary pulley 15 is an output shaft of the continuously variable transmission mechanism 16. The ratio of the input shaft rotational speed to the output shaft rotational speed, that is, the ratio of the primary shaft rotational speed to the secondary shaft rotational speed is the speed ratio of the continuously variable transmission mechanism 16.

  The torque converter 18 has a pump impeller 42 connected to the crankshaft 40 via a front cover 41, and a turbine runner 44 facing the pump impeller 42 and connected to the turbine shaft 43. Further, the torque converter 18 includes a lockup clutch 46 including a clutch plate 45. Further, the torque converter 18 is provided with a starter motor (not shown) for starting the engine 11, and the starter rotation (cranking) of the engine 11 is performed by this starter motor.

  An apply chamber and a release chamber are partitioned inside the torque converter 18 with the clutch plate 45 as a boundary. When the hydraulic pressure in the apply chamber is increased to decrease the hydraulic pressure in the release chamber, the clutch plate 45 is pressed against the front cover 41 and the lockup clutch 46 is engaged. On the other hand, when the hydraulic pressure in the release chamber is increased to decrease the hydraulic pressure in the apply chamber, the clutch plate 45 is separated from the front cover 41 and the lockup clutch 46 is released.

  The lock-up clutch 46 provided in the torque converter 18 is located on the first power transmission path 31 and between the engine 11 and the input clutch 17. When the lock-up clutch 46 is engaged, the power of the engine 11 is Is directly transmitted to the input clutch 17. At this time, if the input clutch 17 is in the engaged state, the output of the engine 11 is directly transmitted to the primary pulley 14. In other words, the output of the engine 11 is transmitted to the primary pulley 14 without any power transmission loss by the torque converter 18.

  The lock-up clutch 46 is connected to the valve unit 23 that controls the hydraulic pressure in the apply chamber and the release chamber as described above. The valve unit 23 is also connected to the continuously variable transmission mechanism 16 and the input clutch 17, and oil for control and lubrication is supplied from the valve unit 23 to the continuously variable transmission mechanism 16 and the input clutch 17.

  A battery 27 is connected to the stator 24 of the electric motor 12 via an inverter 25 and a converter 26. The converter 26 has a function of adjusting the voltage of power supplied from the battery 27 to the inverter 25.

  The vehicle control device 10 includes a control unit 50 for comprehensively controlling the power unit 13. The control unit 50 includes a microcomputer including a CPU, ROM, RAM, and the like, a drive circuit unit that generates control currents for various actuators, and the like, and controls the engine 11, the electric motor 12, and the like. The control unit 50 also controls the continuously variable transmission mechanism 16, the input clutch 17, the torque converter 18, the lockup clutch 46, etc. via the valve unit 23. The control unit 50 is connected to various sensors, cameras, and the like via an in-vehicle network such as CAN. Specifically, the control unit 50 includes an accelerator sensor 51 that detects the operation status of the accelerator pedal, a brake sensor 52 that detects the operation status of the brake pedal, a vehicle speed sensor 53 that detects the vehicle speed, and a camera unit that captures the vehicle surroundings. 54 etc. are connected.

  The vehicle control device 10 having the above-described configuration includes a motor mode in which the wheels 22 are driven by the power of the electric motor 12 and a parallel mode in which the wheels 22 are driven by the power of the engine 11 and the electric motor 12 as travel modes. have. In the motor mode, the input clutch 17 is released and the primary pulley 14 and the engine 11 are disconnected. In this motor mode, the engine 11 is stopped, the electric motor 12 is driven, and the power output from the electric motor 12 is transmitted to the wheels 22. In the parallel mode, the input clutch 17 is engaged and the primary pulley 14 and the engine 11 are connected. In this parallel mode, both the engine 11 and the electric motor 12 are driven, and the power output from the engine 11 and the electric motor 12 is transmitted to the wheels 22.

  As described above, in the motor mode, the engine 11 is stopped and only the electric motor 12 is driven. On the other hand, in the parallel mode, both the engine 11 and the electric motor 12 are driven. The driving mode can be switched according to various conditions, and one of the conditions is a required driving force. The vehicle control device 10 monitors the change in the required driving force, and switches the traveling mode from the motor mode to the parallel mode, or switches from the parallel mode to the motor mode based on the change. When the traveling mode is switched from the motor mode to the parallel mode, it is necessary to start (restart) the engine 11 that has been stopped.

  When starting the engine 11 based on the required driving force, the vehicle control device 10 fastens the input clutch 17, fastens the input clutch 17, and then fastens the lockup clutch 46, and lockup The second start control in which the clutch 46 is engaged and the input clutch 17 is engaged after the lock-up clutch 46 is engaged is selectively executed.

  FIG. 2 is a control map showing an example of setting execution regions for the first start control and the second start control. As shown in FIG. 2, in the control map, a first threshold value α is set for the required driving force, and a second threshold value β is set for the speed ratio of the continuously variable transmission mechanism 16. In the following description, the first threshold value α related to the required driving force may be referred to as “driving force threshold value α”, and the second threshold value β related to the speed ratio of the continuously variable transmission mechanism 16 may be referred to as “speed ratio threshold value β”.

  As shown in FIG. 2, when the required driving force is smaller than the driving force threshold value α and the speed ratio is lower than the speed ratio threshold value β, the second start control is executed. On the other hand, when the required driving force is larger than the driving force threshold value α or when the speed ratio is higher than the speed ratio threshold value β, the first start control is executed.

  That is, when the required driving force is lower than the driving force threshold value α and the speed ratio is lower than the speed ratio threshold value β, the engine is started by the second start control. On the other hand, when the required driving force exceeds the driving force threshold value α or when the speed ratio exceeds the speed ratio threshold value β, the engine is started by the first start control.

  The required driving force is synonymous with the target driving force of the vehicle, and is set based on the depression amount of the accelerator pedal in this embodiment. Specifically, when the amount of depression of the accelerator pedal is large, the required driving force is set large, and when the amount of depression of the accelerator pedal is small, the required driving force is set small. More specifically, the required driving force is set large when the accelerator opening detected by the accelerator sensor 51 shown in FIG. 1 is large, and the required driving force is set small when the accelerator opening is small. . In addition, the transmission ratio of the continuously variable transmission mechanism 16 decreases (decreases) when the continuously variable transmission mechanism 16 is shifted to the speed increasing side, and increases (increases) when the continuously variable transmission mechanism 16 is shifted to the deceleration side.

  FIG. 3 is a flowchart showing a selection procedure for engine start control. As shown in FIG. 3, in step S1, it is determined whether there is an engine start request. If it is determined that there is an engine start request, the process proceeds to step S2. In step S2, the required driving force is compared with the driving force threshold value α, and if it is determined that the required driving force is less than the driving force threshold value α, the process proceeds to step S3. In step S3, the speed ratio is compared with the speed ratio threshold β, and if it is determined that the speed ratio is lower than the speed ratio threshold β, the process proceeds to step S20 and the second start control is executed. Specifically, when it is determined in step S3 that the gear ratio is lower than the gear ratio threshold value β, the process proceeds to step S21 and the lockup clutch 46 is engaged. Next, it progresses to step S22 and the starting rotation of the engine 11 is started. Then, it progresses to step S23 and the input clutch 17 is fastened.

  On the other hand, when it is determined in step S2 that the required driving force exceeds the driving force threshold value α, the process proceeds to step S10 and the first start control is executed. Even when it is determined in step S3 that the gear ratio exceeds the gear ratio threshold β, the process proceeds to step S10 and the first start control is executed. Specifically, if it is determined in step S2 that the required driving force exceeds the driving force threshold α, or if it is determined in step S3 that the gear ratio exceeds the gear ratio threshold β, the process proceeds to step S11 and the engine 11 Start rotation is started. Next, it progresses to step S12 and the input clutch 17 is fastened. Thereafter, the process proceeds to step S13, and the lockup clutch 46 is engaged.

  Here, the timing of shifting from step S22 to step S23, the timing of shifting from step S11 to step S12, that is, the timing at which the input clutch 17 is engaged is such that the rotational speed difference between the engine side and the transmission mechanism side is a predetermined rotational speed difference. When it becomes smaller.

  Selection and execution of the first start control and the second start control as described above are performed by the control unit 50 shown in FIG. That is, the control unit 50 functions as a first control unit that executes the first start control, and also functions as a second control unit that executes the second start control.

  Next, the execution status of engine start by the first start control and the second start control will be described with reference to a timing chart. FIG. 4 is a timing chart showing an execution state of engine start by the second start control, and FIG. 5 is a timing chart showing an execution state of engine start by the first start control.

  FIG. 4 and FIG. 5 show the situation when the driving mode is switched from the motor mode to the parallel mode while the vehicle is traveling, and the engine 11 is started (restarted) in response to this request. ing. Further, the timing chart shown in FIG. 4 shows that when the engine 11 is requested to start, the required driving force is smaller than the driving force threshold value α and the gear ratio is lower than the gear ratio threshold value β. It is assumed that there was. On the other hand, the timing chart shown in FIG. 5 shows that when the engine 11 is requested to start, the required driving force is larger than the driving force threshold α and the gear ratio is higher than the gear ratio threshold β. It is assumed that there was.

  As shown in FIG. 4, under the second start control, the lockup clutch 46 is first engaged, then the engine 11 is started, and then the input clutch 17 is engaged. That is, under the second start control, the engine 11 is started with the lockup clutch 46 engaged. The second start control is executed when the required driving force is small and the gear ratio is low when the engine 11 is requested to start. Therefore, even if the engine 11 is started with the lock-up clutch 46 engaged, a shock accompanying the engine start does not occur or even if it occurs, the shock is small.

  On the other hand, as shown in FIG. 5, under the first start control, the engine 11 is first started, then the input clutch 17 is engaged, and then the lockup clutch 46 is engaged. That is, under the first start control, the lockup clutch 46 is engaged after the engine 11 is started. The first start control is executed when the required driving force is large or the gear ratio is high when the engine 11 is requested to start. Therefore, in order to prevent or suppress a shock associated with starting the engine, it is preferable to start the engine 11 with the lock-up clutch 46 released.

  It is clear from the above description that the switching of the input clutch 17 and the lock-up clutch 46 in the above order is performed by the control unit 50 shown in FIG. More specifically, the control unit 50 functioning as the first control unit and the second control unit outputs a control signal to the valve unit 23 and fastens the input clutch 17 and the lockup clutch 46 from the released state in a predetermined order. Switch to the state or switch from the fastened state to the released state.

  As shown in FIG. 4, under the second start control in which the engine 11 is started with the lockup clutch 46 engaged, there is no power transmission loss by the torque converter 18. Therefore, the engine speed and the turbine runner speed coincide with each other. On the other hand, as shown in FIG. 5, under the first start control in which the lockup clutch 46 is engaged after the engine 11 is started, from the beginning of the start rotation of the engine 11 due to power transmission loss by the torque converter 18. There is a difference between the engine speed and the turbine runner speed. Specifically, the engine speed continues to be higher than the turbine runner speed from the beginning of the start rotation. Further, the slip of the torque converter 18 causes a phenomenon called “swelling up” or “overshoot” in which the engine speed temporarily exceeds the turbine runner speed immediately after the engine is started.

  As described above, the second start control has an advantage that deterioration of fuel consumption due to power transmission loss of the torque converter 18 is suppressed. In addition, there is an advantage that engine "swelling" or "overshoot" due to slip of the torque converter 18 is avoided. On the other hand, the first start control has an advantage that a shock accompanying the start is prevented or suppressed when the engine is started in a situation where the required driving force is large or the gear ratio is high. Since the vehicle control device 10 selectively executes the first start control and the second start control, each having the above advantages, according to the required driving force and the gear ratio, the advantages of both can be obtained. Furthermore, by selectively executing the first start control and the second start control, the number of times that the lockup clutch 46 is fastened while the engine 11 is started is reduced, and the service life of the lockup clutch 46 is extended.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above embodiment, both the required driving force and the gear ratio are used as a reference for selecting the first braking control or the second braking control. However, in relation to the occurrence of shock and the magnitude of the shock associated with engine start, the influence of engine torque at engine start is greater than the gear ratio at engine start. Therefore, only the required driving force may be used as a reference for selecting the first braking control or the second braking control. That is, regardless of the gear ratio, the first start control is executed when the required driving force at the time of engine start exceeds the driving force threshold value α, and the second start control when the required driving force is lower than the driving force threshold value α. May be executed.

  In the above embodiment, the input clutch 17 is disposed between the lock-up clutch 46 and the continuously variable transmission mechanism 16, but the position of the input clutch 17 is not limited to this. The input clutch 17 can be disposed at an arbitrary position in the power transmission path, and may be disposed between the continuously variable transmission mechanism 16 and the differential mechanism 21, for example.

  The input clutch 17 in the above embodiment is a plate clutch that is hydraulically controlled, but the input clutch 17 may be replaced with an electromagnetic clutch. Further, instead of the continuously variable transmission mechanism 16, a parallel shaft type or planetary gear type transmission mechanism may be adopted as the transmission mechanism.

  The vehicle to which the vehicle control device of the present invention is applied is not limited to a hybrid vehicle including an engine and a motor generator. For example, the vehicle control device of the present invention can be applied to a vehicle using only an engine as a power source or a vehicle using only a motor generator as a power source.

DESCRIPTION OF SYMBOLS 10 Vehicle control apparatus 11 Engine 12 Motor generator (electric motor)
16 Transmission mechanism (continuously variable transmission mechanism)
17 Input clutch 22 Wheel (drive wheel)
31 Power transmission path (first power transmission path)
32 Power transmission path (second power transmission path)
46 Lock-up clutch 50 Control unit α First threshold (driving force threshold)
β Second threshold (speed ratio threshold)

Claims (6)

A vehicle control device including an engine that is started based on a required driving force,
An input clutch provided in a power transmission path connecting the engine and the drive wheels, and transmitting power of the engine to the drive wheels;
A lockup clutch that is provided between the engine and the input clutch and transmits the power of the engine to the input clutch;
When starting the engine based on the required driving force, a first control unit that performs a first start control that engages the input clutch and that engages the lock-up clutch after the input clutch is engaged;
When starting the engine based on the required driving force, a second control unit that performs a second start control that engages the lock-up clutch and that engages the input clutch after the lock-up clutch is engaged;
Have
When the required driving force exceeds a first threshold value, the first start control is executed, and when the required driving force is lower than the first threshold value, the second start control is executed. Control device. The vehicle control device according to claim 1,
In the second start control, the vehicle control device starts starting rotation of the engine after the lock-up clutch is engaged and then engages the input clutch. The vehicle control device according to claim 1 or 2,
A transmission mechanism provided in the power transmission path;
A vehicle control device that executes the second start control when the required driving force is less than the first threshold value and a speed ratio of the transmission mechanism is less than a second threshold value. The vehicle control device according to claim 3,
The transmission mechanism is a continuously variable transmission mechanism,
The vehicle control apparatus, wherein the gear ratio is a ratio of an input shaft rotation speed to an output shaft rotation speed of the transmission mechanism. The vehicle control device according to claim 3 or 4,
The input clutch is a vehicle control device provided between the lock-up clutch and the speed change mechanism. In the vehicle control device according to any one of claims 1 to 5,
A vehicle control device having a motor generator connected to the power transmission path on the drive wheel side of the input clutch.

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