JP5476732B2 - Vehicle shift control device and shift control method - Google Patents

Description

  The present invention relates to a vehicle shift control device and a shift control method for generating a hydraulic pressure of a pump by a rotational force of a motor and changing a transmission gear ratio by the hydraulic pressure.

A conventional hybrid vehicle has a structure in which a clutch is provided between an engine and a motor and between the motor and a transmission. Then, switching between EV travel (motor travel) and HEV travel (hybrid (motor + engine) travel), braking regeneration, and the like are controlled by appropriately controlling the engagement state of these clutches.
In addition, when the vehicle speed decreases or stops, the transmission gear ratio is set to a lower side than the current gear ratio in advance during the deceleration in order to enable smooth acceleration and re-start. Controls to shift. For example, in Patent Document 1 below, when the vehicle speed is lower than a threshold value or the speed ratio is smaller than a reduction ratio that can be sufficiently accelerated, the input shaft of the CVT is set so that the speed ratio of the transmission (CVT) is increased as the speed reduction ratio. Set the target rotation speed. Then, CVT shift control is performed by driving an electric oil pump that generates hydraulic pressure when hydraulically controlling the CVT.

JP 2006-70265 A

By the way, the transmission of such a hybrid vehicle performs a shift operation by the hydraulic pressure from a hydraulic pump that is operated by the rotational force of the drive motor connected to the input shaft.
Therefore, when the rotational speed of the input shaft of the transmission decreases due to a decrease in vehicle speed and the rotational force of the motor decreases, the hydraulic pressure of the hydraulic pump also decreases accordingly.
As a result, the hydraulic pressure necessary to operate the transmission cannot be secured sufficiently, and the transmission cannot be changed to the speed ratio (Low side) required for restart, and smooth acceleration and restart cannot be performed. is there.
Therefore, the present invention has been devised to solve such a problem, and the object of the present invention is to make sure that the speed change ratio (Low side) required for restarting the transmission reliably even when the vehicle speed decreases. The present invention provides a novel shift control apparatus and shift control method for a vehicle.

In order to achieve the above object, the present invention provides a motor for generating a driving force, a transmission located between the motor and driving wheels, a clutch control means for connecting them, and a transmission for controlling the transmission. The present invention relates to a transmission control device for a vehicle having a machine control means.
The clutch control means determines whether or not a predetermined hydraulic pressure for shifting the transmission to a predetermined gear ratio can be obtained by reducing the number of rotations of the motor when the vehicle decelerates while the motor is engaged with the clutch. Determine. When it is determined that the predetermined hydraulic pressure cannot be obtained, the clutch is shifted from the engaged state to the sliding engaged state so that the motor maintains a rotational speed that is equal to or higher than the rotational speed at which the predetermined hydraulic pressure can be generated.
On the other hand, the transmission control means changes the transmission gear ratio of the transmission to a lower transmission gear ratio than the present one by the predetermined hydraulic pressure when the clutch shifts to the slip engagement state.
Further, when the rotational speed of the motor is increased when the transmission gear ratio is changed to a predetermined gear ratio, the clutch is slip-engaged until the transmission completes shifting to the predetermined gear ratio. Continue state.

  According to the present invention, even if the speed of the vehicle is reduced, the rotational speed of the motor can be maintained at a predetermined rotational speed. As a result, a sufficient hydraulic pressure for changing the transmission gear ratio can be secured, so that the transmission can be reliably changed to the transmission gear ratio (Low side) required for re-start.

1 is an overall configuration diagram showing an embodiment of a hybrid vehicle 100 according to the present invention and a shift control device (drive control device) applied thereto. It is a block diagram which shows the shift control process which concerns on this invention. It is a flowchart figure which shows an example of the flow of the shift control method which concerns on this invention.

Hereinafter, an embodiment of a braking force control device of the present invention will be described with reference to the accompanying drawings.
(Constitution)
FIG. 1 is an overall configuration diagram showing a hybrid vehicle 100 equipped with a transmission control device of the present invention.
As illustrated, the hybrid vehicle 100 includes an engine 1, a motor 2, a continuously variable transmission (CVT) 3, a first clutch 4, and a second clutch 5. The hybrid vehicle 100 further includes a hybrid controller 6, a brake pedal force sensor 7, a vehicle speed sensor 8, a hydraulic pump 9, and drive wheels (tires) 10 and 10.
The engine 1 includes an internal combustion engine such as a gasoline engine or a diesel engine. The engine 1 generates torque for driving the vehicle in accordance with a driver's torque request (specifically, accelerator opening) based on a control command from the hybrid controller 6.

  The motor 2 includes a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. The motor 2 responds to a driver's torque request (specifically, accelerator opening) by applying a three-phase alternating current generated by an inverter (not shown) based on a control command from the hybrid controller 6. Output torque. The motor 2 generates drive torque alone (EV travel) when the torque request is low, and assists (HEV (hybrid) travel) the drive torque of the engine 1 when the torque request is high. The motor 2 functions as a generator that generates electromotive force at both ends of the stator coil and charges a battery (not shown) when the rotor is rotated by external force during braking (regenerative braking).

The motor 2 also functions as a drive source for the hydraulic pump 9 for controlling the gear ratio of the continuously variable transmission (CVT) 3.
The hydraulic pump 9 operates based on a control command from the hybrid controller 6 and controls the transmission ratio of the continuously variable transmission (CVT) 3 by adjusting the hydraulic pressure generated by the rotational force (driving force) of the motor 2. To do. The hydraulic pump 9 controls the first clutch 4 and the second clutch 5 by adjusting the hydraulic pressure generated by the rotational force (driving force) of the motor 2 based on the control command from the hybrid controller 6.

  The continuously variable transmission (hereinafter referred to as “CVT” as appropriate) 3 operates based on a control command from the hybrid controller 6 so as to appropriately transmit the torque of the engine 1 and the motor 2 to the drive wheels 10 and 10. The gear ratio (primary and secondary) is set. In actual torque transmission, torque is transmitted from the input shaft (primary shaft) 3a connected via the second clutch 5 to the output shaft (secondary shaft) 3b, and is transmitted to the drive wheels 10 and 10 via a differential gear (not shown). .

  The first clutch 4 includes a hydraulic single-plate clutch interposed between the engine 1 and the motor 2. The first clutch 4 operates based on a control command from the hybrid controller 6 and controls torque transmission between the engine 1 and the motor 2. Then, for example, the engagement is released during EV traveling, the engagement state is achieved during HEV traveling and traveling with only the torque of the engine 1, and the sliding engagement (slip) state is established when the engine is started.

  The second clutch 5 operates based on a control command from the hybrid controller 6 and controls torque transmission between the motor 2 and the CVT 3. As will be described in detail later, it is engaged during normal travel (EV travel or HEV travel) or during regenerative braking (except in some cases), but is released during charging or deceleration. It will be in a state (non-fastening) or a slip fastening (slip) state.

The driving wheels (tires) 10 and 10 have a function of obtaining driving force from the input shaft 3a of the CVT 3 and transmitting torque of the engine 1 and the motor 2 to the road surface via the CVT 3. Further, it has a function of transmitting kinetic energy (inertial force) to the motor 2 via the CVT 3 during deceleration and regenerative braking.
The brake pedal force sensor 7 detects a brake pedal force generated by a driver operation, and has a function of transmitting the detected information to the hybrid controller 6.
On the other hand, the vehicle speed sensor 8 detects the speed of the vehicle based on the rotational speed of a front wheel (not shown) and has a function of transmitting the detected information to the hybrid controller 6.
The hybrid controller 6 controls the transmission ratio of the CVT 3 and the torque capacity of the second clutch 5 based on information from the brake pedal force sensor 7 and the vehicle speed sensor 8.

(Function)
Next, a control method by the shift control device of the hybrid vehicle 100 configured as described above will be described with reference to the control block diagram of FIG. 2 and the flowchart of FIG.
(Step S1)
First, in the first step S1, the hybrid controller 6 determines whether or not the brake is stepped on during EV traveling based on an input signal relating to the actual brake pedal force from the brake pedal force sensor 7. As a result, when it is determined that the brake is not depressed (No), the system waits until the brake is depressed. Conversely, when it is determined that the brake has been depressed (Yes), the process proceeds to the next step S3.

(Step S3)
In step S3, the target deceleration is obtained based on the actual brake pedal force value and the actual vehicle speed value detected by the vehicle speed sensor 8 at that time, and then the process proceeds to the next step S5. The target deceleration value is defined in advance for the vehicle speed and the brake pedal force.
(Step S5)
In step S5, the vehicle speed, motor speed, pump hydraulic pressure, CVT3 speed, and CVT3 speed ratio change over time from the motor 2 speed, CVT3 speed ratio, and target (command) deceleration at that time. After calculating and predicting (calculating from each characteristic data), the process proceeds to the next step S7.

(Step S7)
In step S7, it is determined whether or not the transmission ratio of CVT3 at the time when the vehicle speed becomes 0 (zero) (stops) in the predicted time transition of these parameters can be changed to a low transmission ratio to a transmission ratio necessary for restart. (Low return possibility determination). As a result, when it is determined that the low speed can be achieved up to the speed ratio required for restart (Yes), the processing is ended as it is. On the other hand, when it is determined that the low speed change is not possible to the speed change ratio required for restart (No), the process proceeds to the next step S9.

(Step S9)
In step S9, in order to secure the hydraulic pressure used for shifting the CVT 3 while decelerating, it is specified that the motor 2 changes at a higher speed than the time change of the motor speed predicted in the step S5, and then the last step. The process proceeds to S11. At this time, it is defined excluding the constraint that the rotational speed of the input shaft 3a of the CVT 3 must be equal to the rotational speed of the motor.

(Step S11)
In step S11, the motor speed is set so that the CVT3 gear ratio at the time when the vehicle speed becomes zero (stops) at the time when the vehicle speed becomes zero (stops) can be low-shifted to the gear ratio required for re-start by the same calculation method as in the low return possibility determination in step S7. Specify the time transition. In addition, the temporal transition of the rotational speed of the input shaft 3a of the CVT 3 is also defined. The time transition of the differential rotation of the second clutch 5 is calculated from these two. If the brake is stepped on while driving and the low return determination is not possible, the hydraulic pressure of the second clutch 5 is set so that the differential rotation is generated according to the temporal transition of the differential rotation of the second clutch 5. Ford back control and slide. In addition, the motor 2 performs the rotational speed feedback control so that the time changes as prescribed.

Thereby, at the time of sudden deceleration and sudden stop, the hydraulic pressure of the hydraulic pump 9 for shifting can be secured until the gear ratio of the CVT 3 is changed to the Low side until it is reaccelerated or restarted. The certainty and acceleration performance at the time of start are improved.
Further, since the CVT input limit torque has a characteristic that the margin becomes higher as the gear ratio of CVT 3 is closer to the Low side, the start applied to the second clutch 5 by applying the shift control as in the present embodiment. Since the time burden can be reduced, the second clutch 5 is protected.

In addition, it is not necessary to install a clutch on the axle side of the CVT 3 for the purpose of performing the low return without stopping the rotation of the axle while the vehicle is stopped, by reducing the gear ratio before the vehicle stops. Is also possible.
In addition, since a sufficient torque can be transmitted to the drive wheels 10 and 10 at the initial stage of the next start and the initial stage of acceleration, the response of the start and acceleration is improved.

  In the present embodiment, the hybrid vehicle driven by the engine 1 and the motor 2 has been described as an example. However, the present invention is not limited to such a hybrid vehicle. That is, in addition to the motor 2 as a driving source, the hydraulic pump 9 driven by the motor 2, the CVT 3 controlled by the hydraulic pump 9, and the driving force of the motor 2 to be transmitted to the CVT 3 If it is the structure which has this clutch (2nd clutch 5), it is possible to apply as it is to other vehicles, such as a fuel cell vehicle and a motor vehicle, for example.

  Further, when the rotational speed of the input shaft 3a of the CVT 3 is increased with the assistance of the motor 2 to increase the shift speed, the vehicle will accelerate unless the shift speed of the CVT 3 can catch up with the assist with the motor 2. However, according to the shift control according to the present embodiment, even in such a case, the necessary oil pressure can be obtained while reducing the torque transmission capacity of the second clutch 5 and sliding the second clutch 5 to suppress acceleration. The gear ratio can be reliably changed to the Low side. As a result, a sense of incongruity caused by a change in acceleration / deceleration during deceleration can be prevented, so that drivability is improved.

  Further, the “clutch control means” constituting the speed change control device of the present invention disclosed in the means for solving the problems corresponds to the hybrid controller 6, the hydraulic pump 9, the motor 2, and the like in the present embodiment. Similarly, “transmission control means” corresponds to the hybrid controller 6, the hydraulic pump 9, the motor 2, and the like in the present embodiment. The “clutch” corresponds to the second clutch 5 in the present embodiment.

(effect)
Next, the effect of this embodiment will be described.
According to the shift control device and the shift control method according to the present embodiment, the following effects are exhibited.
(1) When it is determined that a predetermined hydraulic pressure for shifting the CVT 3 to a predetermined gear ratio cannot be obtained due to a decrease in the rotational speed of the motor 2 due to the vehicle decelerating while the motor is running, the second clutch 5 From the fastening state to the sliding fastening state. Then, the gear ratio of the CVT 3 is changed to a gear ratio lower than the current gear ratio by the predetermined hydraulic pressure in the slip engagement state.
Thereby, even if the speed of the vehicle decreases, the rotational speed of the motor 2 can be maintained at a predetermined rotational speed. As a result, the hydraulic pressure for controlling the gear ratio of CVT 3 can be sufficiently secured, so that CVT 3 can be reliably changed to the gear ratio (Low side) necessary for restart.

(2) When the rotation speed of the motor 2 is increased in order to change the transmission ratio of the CVT 3 to a predetermined transmission ratio when the second clutch 5 is in the sliding engagement state, the CVT 3 changes to the predetermined transmission ratio. Until the end, the second clutch 5 continues the sliding engagement state.
Thereby, even if the rotation speed of the motor 2 becomes higher than the vehicle speed, the second clutch 5 absorbs the rotation difference, so that the change in the deceleration of the vehicle can be suppressed. As a result, the uncomfortable feeling given to the driver can be reduced.

DESCRIPTION OF SYMBOLS 100 ... Hybrid vehicle 1 ... Engine 2 ... Motor 3 ... Transmission (CVT)
3a: Input shaft (primary pulley)
3b ... Output shaft (secondary pulley)
4 ... 1st clutch 5 ... 2nd clutch (clutch)
6 ... Hybrid controller (clutch control means, shift control means)
7 ... Brake pedal force sensor 8 ... Vehicle speed sensor 9 ... Hydraulic pump 10 ... Drive wheel (tire)

Claims (2)

A motor that generates a driving force, a transmission that is positioned between the motor and the driving wheel, a clutch control unit that controls a clutch that connects the motor and the transmission, and a hydraulic pressure that is generated by the rotational force of the motor. A transmission control device for a vehicle having transmission control means for controlling a transmission ratio of the transmission,
The clutch control means is unable to obtain a predetermined hydraulic pressure for shifting the transmission to a predetermined gear ratio due to a decrease in the rotational speed of the motor when the vehicle decelerates during driving of the motor with the clutch engaged. When it is determined that, the clutch shifts from the engaged state to the slip engaged state,
The transmission control means changes the transmission gear ratio to a lower transmission gear ratio than the current gear ratio by the predetermined hydraulic pressure when the clutch shifts to the slip engagement state .
When the speed of the motor is increased when the transmission gear ratio is changed to a predetermined transmission gear ratio, the clutch control means is configured until the transmission finishes shifting to the predetermined transmission gear ratio. A shift control apparatus for a vehicle, wherein the clutch continues in a slip engagement state . A transmission control method for a vehicle, in which a motor and a transmission are connected by a clutch, the clutch is controlled, and the transmission is controlled to be shifted by hydraulic pressure generated by the rotational force of the motor,
When it is determined that a predetermined hydraulic pressure for shifting the transmission to a predetermined gear ratio cannot be obtained due to a decrease in the number of rotations of the motor while the motor is driven while the motor is engaged with the clutch. The clutch shifts from the engaged state to the slip engaged state, and in the slip engaged state, the transmission gear ratio of the transmission is changed to a lower transmission gear ratio by the predetermined oil pressure, and the transmission gear ratio is predetermined. When the number of rotations of the motor is increased when the gear ratio is changed , the vehicle keeps the clutch engaged and engaged until the transmission finishes shifting to the predetermined gear ratio. Shift control method.

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