KR101500351B1 - Method for controlling of hybrid vehicle and method thereof - Google Patents

Abstract

In the present invention, when the hybrid vehicle is switched to an HEV (Hybrid Electric Vehicle) mode during low-speed traveling in an EV (Electric Vehicle) mode, the torque input to the transmission is slightly lowered, The slip control of the engine clutch is performed by adjusting the hydraulic pressure amount in accordance with the temperature of the engine clutch.

The present invention relates to a control method of a hybrid vehicle comprising the steps of detecting a transition from a low speed running state to an HEV mode in an EV mode and controlling a coupling of an engine clutch by determining a transmission input torque to be lower than a flat torque, Calculating a temperature of the engine clutch when the hybrid vehicle is operated in the slip traveling mode by switching to the HEV mode and executing the slip control by adjusting the amount of hydraulic pressure according to the temperature of the engine clutch; And controlling the engine clutch to be engaged by setting the rotation speed higher than the normal flat running mode.

Hybrid vehicle, engine clutch, engine torque, mode switching, backlit, low-speed driving

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hybrid vehicle control method,

The present invention relates to a hybrid vehicle, and more particularly, to a hybrid vehicle in which when an engine is switched to an HEV (Hybrid Electric Vehicle) mode during a low speed traveling in a back road in an EV (Electric Vehicle) To a hybrid vehicle control system in which when the hybrid vehicle is operated in the slip traveling mode in the HEV mode, the slip control of the engine clutch is performed by adjusting the hydraulic pressure amount in accordance with the temperature of the engine clutch.

The hybrid vehicle is equipped with an engine clutch which is operated by an engine and a battery as a power source to apply an output torque of the engine to assist the output torque of the engine and interrupts the output torque of the engine between the engine and the motor.

A hybrid electric vehicle composed of an engine and a motor is an EV mode in which an engine clutch is not engaged but is driven only by a motor, an HEV mode in which an engine clutch is engaged and an engine and a motor are used as a driving force, There is a slip running mode in which the torque of the engine is transmitted in a state where the rotation speed of the engine and the motor are different.

When the input RPM inputted to the transmission is less than the idle RPM of the engine by the sum of output torque of the engine and the motor due to the engagement of the engine clutch in the HEV mode, the engine clutch is controlled to be in a slip state to transmit the driving force of the engine to the transmission, The amount of oil pressure of the engine clutch is adjusted to deliver the target engine torque.

Currently, the control logic applied to the hybrid vehicle does not distinguish the backing condition, so the control logic of the general flat running condition is used.

When the control logic of the general flat running condition is applied, the running demand torque such as the flat running is applied when transitioning from the EV mode to the HEV mode at the back-running, and the combined RPM of the engine clutch is set to a low RPM as in the flat .

Further, the slip hydraulic pressure amount of the engine clutch is also constantly applied.

The technology applied to the conventional hybrid vehicle has the following problems in the EV mode, the sleep drive mode, and the HEV mode.

If the vehicle shifts from the EV mode to the HEV mode during the low-speed traveling of the backlit road, the driving demand torque of the HEV mode is applied as a flat condition, so that the condition is set too high to be used as it is in the backing condition.

In this case, due to excessive use of the EV mode driven only by the motor, continuous battery discharge is inevitable and the SOC (State Of Charge) of the battery is not maintained, so that the battery can not be backed up until the SOC of the battery is charged to a certain level or more .

Further, the SOC of the battery is weakened, resulting in deterioration of fuel consumption and a problem of reducing the durability of the battery.

In addition, since the slip hydraulic pressure amount of the engine clutch is controlled to a constant slip hydraulic pressure amount without applying a condition depending on the difference in rotational speed between the engine and the engine clutch, the temperature of the engine clutch rises excessively when the slip mode travel continues, Resulting in a phenomenon in which running is impossible.

Also, since the maximum output torque of the engine can not be used, the amount of charge of the motor is relatively reduced, and the SOC of the battery can not be maintained stably.

Finally, since the rotational speed of the engine to which the engine clutch is coupled is set to the flat condition, the engine output torque is unstable due to the low speed operation to the back plate, the drivability is deteriorated, the available torque of the engine is insufficient, So that the SOC is weakened.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a torque converter which is capable of determining an input torque of a transmission to be somewhat lower than a flat torque when switching to an HEV mode during low- So that the SOC of the battery can be stably maintained by minimizing the amount of discharge by the motor.

Further, the present invention provides a durability of the engine clutch by controlling the slip of the engine clutch by adjusting the hydraulic pressure amount in accordance with the temperature of the engine clutch when the slip running mode is switched to the HEV mode while the backing road is running at low speed, And the charge of the battery is induced by the torque, so that the SOC is stably maintained.

In addition, when the engine is switched to the HEV mode during the low-speed running of the backhoe, the possible engine rotational speed at which the engine clutch is engaged is set to be somewhat higher in the backlash mode than in the normal flat running mode, Thereby improving the operability and ensuring that the charging of the battery is stably maintained by the rise of the torque available for the engine.

According to an aspect of the present invention, an engine and a motor, an engine clutch disposed between the engine and a motor, a transmission, and a controller are integrally controlled through a network to control an output torque of the engine and a motor, A hybrid vehicle comprising a hybrid controller for controlling an EV mode and an HEV mode by controlling a clutch,

The hybrid controller is configured to determine and control the engine speed at which the torque input to the transmission and the engine clutch are coupled to each other and the slip hydraulic pressure amount of the engine clutch when the hybrid vehicle is switched to the HEV mode during low speed traveling in the back road in the EV mode.

A method of controlling a hybrid vehicle according to an embodiment of the present invention includes the steps of detecting a transition from a low speed running state to a HEV mode in an EV mode; Controlling the engagement of the engine clutch by determining the transmission input torque to be lower than the flat torque when the switching to the HEV mode is detected; Calculating the temperature of the engine clutch when the mode is shifted to the HEV mode and operating in the slip traveling mode, and performing the slip control by adjusting the hydraulic pressure amount according to the temperature of the engine clutch; And switching the engine clutch to the HEV mode to fully engage the engine clutch, thereby setting the engine rotation speed higher than the normal flat running mode, thereby controlling the engine clutch.

According to the above-described configuration, the hybrid vehicle according to the present invention is capable of improving the problem of clutch burnout and the deterioration of drivability, as well as the inability to travel due to the exhaustion of the SOC of the battery when the vehicle travels to the low speed back plate.

In addition, since the improvement effect is significant without any additional hardware changes, it provides performance improvement without cost increase and ensures price competitiveness.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains.

The present invention can be embodied in various different forms, and thus the present invention is not limited to the embodiments described herein.

1 is a view schematically showing a control apparatus of a hybrid vehicle according to an embodiment of the present invention.

An engine control unit (HCU) 20, an MCU (motor control unit) 30, a battery 40, a battery management system (BMS) 50, a transmission control unit (TCU) 60, an engine 70, a motor 80, an engine clutch 90, and a transmission 100.

The ECU 10 controls the overall operation of the engine 80 and the output torque under the control of the HCU 20 connected to the network.

In the course of adjusting the output torque of the engine 80, the ECU 10 adjusts the magnitude of the output torque by applying an Accel Position Sensor (APS) signal, which is a deceleration demand of the driver.

The HCU 20 controls the output torque of the engine 70 and the motor 80 by integrally controlling each controller through the network according to the driving request and the vehicle condition and controls the engine clutch 90 in accordance with the operating condition condition Controls the travel of EV mode and HEV mode.

When the HCU 20 is switched to the HEV mode during low-speed running of the backlash in the EV mode, the HCU 20 generates torque, which is determined by the sum of the engine 70 and the motor 80 input to the transmission 100 via the engine clutch 90 Is determined to be somewhat lower than the flat torque to control the engagement of the engine clutch (90). Here, the flat torque represents the torque required in the flat travel mode.

Accordingly, stability is provided for torque switching, and the amount of discharge by the motor is minimized, so that the SOC of the battery is stably maintained.

When the HCU 20 is in the HEV mode and is operating in the slip driving mode while driving the backing plate at low speed, the temperature of the oil for operating the engine clutch 90, the slip temperature of the engine clutch 90, The temperature of the engine clutch 90 is calculated by applying the temperature condition and then the amount of oil pressure is adjusted in accordance with the temperature of the engine clutch 90 to control the slip of the engine clutch 90. [

Therefore, the durability of the engine clutch 90 is improved, and the charging of the battery 40 is induced by the surplus torque, so that the SOC is stably maintained.

When the HCU 20 is operated in the HEV mode during the low speed running of the backing plate and is operated with the engine clutch 90 fully engaged, the rotation speed of the engine 70, which engages the engine clutch 90, The running performance is improved by securing a sufficient output torque of the engine and the charging of the battery 40 is stably maintained by the increase of the engine-use torque.

The MCU 30 drives the motor 80 under the control of the HCU 20 connected to the network to adjust the output torque and stores the regenerative braking energy of the motor 80 in the battery 40 at the time of regenerative braking.

The battery 40 supplies power to the motor 80 in the EV mode to maintain the running and supplies power to the motor 80 in the HEV mode to assist the output torque of the engine 70 or to output the output of the engine 70 And charges the voltage recovered through the motor 70 during the regenerative braking control.

The BMS 50 manages and controls the SOC (state of charge) state and charge / discharge current amount of the battery 40 by detecting the information of the voltage, the current, and the temperature of the battery 40, .

The TCU 60 controls the shifting operation of the transmission 100 according to the current operating condition under the control of the HCU 20 connected to the network.

The engine 70 controls the overall output torque under the control of the ECU 20, and adjusts the intake air amount in accordance with the opening ratio of the throttle valve adjusted by ETC (Electric Throttle Control) not shown.

The motor 80 adjusts the drive torque under the control of the MCU 30, and generates a regenerative braking torque in accordance with the regenerative braking amount at the regenerative braking.

The engine clutch 90 is disposed between the engine 60 and the motor 70 and is operated under the control of the HCU 20 to determine an operation mode as an EV mode, an HEV mode, and a slip drive mode.

The transmission 100 is supplied with the output torque of the engine 70 and the output torque of the motor 80 which are determined in accordance with engagement and disengagement of the engine clutch 90 as input torque, And the driving force is outputted to the driving wheels to maintain the driving.

The operation of the present invention including the functions described above will be described as follows.

Since the control of the hybrid vehicle is performed in the same manner as the normal operation, a detailed description thereof will be omitted. In the EV mode, the vehicle is switched to the HEV mode during the low- Only the control operation according to the control mode and the full coupling will be described.

2, in a state where the hybrid vehicle to which the present invention is applied travels in the EV mode (S101), the HCU 20 determines whether a mode change has occurred in the HEV mode (S102).

If it is determined in S102 that the changeover from the EV mode to the HEV mode has occurred, the gradient of the area to be driven, the traveling speed and the average speed are detected (S103) and it is determined whether the backing road is traveling at a low speed (S104). That is, it is possible to determine whether the vehicle is running at a low speed when the running speed is lower than the average speed.

If it is determined in S104 that the vehicle is running at a low speed, the low-speed running back mode in which the input torque of the transmission 100 is set lower than that of the general flat running mode is applied (S105) to determine the output torque of the HEV mode (S106).

Thereafter, the engine clutch 90 is engaged (S107), and the combined torque of the engine 70 and the motor 80 is input to the transmission 100, thereby providing the HEV mode of running (S108).

Therefore, by minimizing the discharge of the battery 40 by the motor 80, the SOC of the battery 40 is stably maintained.

If it is determined that the engine is not running at low speed in step S104, the general flat running mode is applied in step S109, the output torque of the HEV mode is determined in step S110, the engine clutch 90 is engaged in step S107, The summed torque of the engine 80 is input to the transmission 100, thereby providing a running of the HEV mode (S108).

3, when the hybrid vehicle to which the present invention is applied travels in the EV mode at a low speed (S101), the HCU 20 changes the mode to the HEV mode (S202).

If it is determined in S202 that the transition from the EV mode to the HEV mode has occurred, the HCU 20 determines the general driving condition of the vehicle (S203) and determines whether the mode is the slip driving mode of the engine clutch 90 (S204).

If it is determined in step S204 that the engine clutch 90 is in the slip travel mode, the conditions of the oil temperature for operating the engine clutch 90 and the slip temperature and the cooling temperature of the engine clutch 90 are applied to determine the temperature of the engine clutch 90 (S205).

The slip temperature of the engine clutch 90 is determined by the conditions of the variation of the engine speed and the hydraulic pressure, and the cooling temperature is determined by the conditions of the flow rate of the cooling water.

When the temperature of the engine clutch 90 is calculated in S205, the slip control hydraulic pressure amount of the engine clutch 90 for transmitting the target engine torque in accordance with the temperature of the engine clutch 90 is calculated (S206) The engine clutch 90 is slip-controlled (S207).

The calculation of the slip control oil pressure amount of the engine clutch 90 for transmitting the target engine torque is performed by calculating the difference between the current revolution number of the engine 70 and the required idle revolution number and the difference between the maximum output torque of the engine 70 and the present revolution number Adjust the hydraulic gain according to the difference in output torque.

For example, when the current number of revolutions of the engine 70 is larger than the required idle revolution number, the gain of the slip control oil pressure amount of the engine clutch 90 is increased to increase the oil pressure amount, thereby increasing the load of the engine 70 The current rotation speed of the engine 70 is reduced.

However, when the current revolution speed of the engine 70 is smaller than the required idle revolution speed, the gain of the slip control oil pressure amount of the engine clutch 90 is reduced to reduce the oil pressure amount, thereby reducing the load on the engine 70, In the direction in which the current number of revolutions is increased.

Therefore, it is possible to reduce the difference between the current number of revolutions of the engine 70 and the required number of idle revolutions, thereby suppressing the temperature rise of the engine clutch 90 and efficiently transmitting the output torque of the engine 70, .

The required idle speed as a reference is set to a good charging efficiency of the HSG (hybrid starter generator) so that the battery can be effectively charged through the HSG in the EV mode.

When the current output torque is smaller than the maximum output torque of the engine 70, the gain for adjusting the hydraulic pressure is increased to increase the hydraulic pressure, so that the engine 70 can increase the torque, So that stable SOC can be maintained.

At this time, based on the maximum output torque of the engine 70, the hydraulic pressure amount is increased or decreased by the difference between the present output torque and the present output torque.

The reason why the torque of the engine 70 is based on the maximum torque is that the torque of the engine 70 that is left to be used as the running torque acts as the charging torque of the motor 80 so that the charging of the battery 40 is provided

If the engine clutch 90 is not in the slip travel mode in S204, it is determined that the engine clutch 90 is fully engaged and traveled (S208), and the rotation of the engine 70 for engaging the engine clutch 90 (S209) and then engages the engine clutch 90 to provide driving of the HEV mode.

The rotational speed of the engine 70 for engaging the engine clutch 90 is set higher in the backlash mode than in the normal flat running mode so that a sufficient output torque of the engine 70 is ensured, The charge of the battery 40 is provided by the rise of the available torque of the engine 70 so that a stable SOC is secured.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It is included in the scope of right.

1 is a view schematically showing a control apparatus of a hybrid vehicle according to an embodiment of the present invention.

2 to 3 are flowcharts showing a control procedure of a hybrid vehicle according to an embodiment of the present invention.

Description of the Related Art

10; ECU 20: HCU

30: MCU 40: Battery

50: BMS 60: TCU

70: engine 80: motor

90: engine clutch 100: transmission

Claims (8)

A hybrid control system that controls the output torque of the engine and the motor by integrally controlling the engine and the motor, the engine clutch installed between the engine and the motor, the transmission and the network, and controls the EV clutch and the HEV clutch In a hybrid vehicle including a controller, The hybrid controller determines and controls the engine speed at which the torque input to the transmission and the engine clutch are coupled to each other and the slip hydraulic pressure amount of the engine clutch when the hybrid vehicle is switched to the HEV mode while the low- Wherein the low speed indicates a case where the running speed is equal to or less than an average speed. The method according to claim 1, The hybrid controller When the engine is switched to the HEV mode during low-speed running of the backhoe in the EV mode, the transmission input torque determined by the sum of the engine and the motor is determined to be lower than the flat torque through the engine clutch, And the flat torque represents a torque required in the flat running mode. The method according to claim 1, The hybrid controller includes: In the EV mode, when the engine is switched to the HEV mode while the vehicle is running at low speed, the engine clutch temperature, the engine slip temperature, and the cooling temperature are applied to operate the engine clutch, And the slip control is executed by adjusting the hydraulic pressure amount in accordance with the temperature of the engine clutch. The method according to claim 1, The hybrid controller includes: The engine clutch is controlled to be engaged by setting the engine rotational speed higher than the normal flat running mode when the engine is switched to the HEV mode while the backlash is traveling at low speed in the EV mode. A step of detecting a traveling speed and an average speed traveling on a back road in an EV mode, determining that the traveling speed is a low speed traveling when the traveling speed is equal to or lower than an average speed, and detecting switching from a low speed traveling state to an HEV mode; Controlling the engagement of the engine clutch by determining the transmission input torque to be lower than the flat torque when the switching to the HEV mode is detected; Calculating the temperature of the engine clutch when the mode is shifted to the HEV mode and operating in the slip traveling mode, and performing the slip control by adjusting the hydraulic pressure amount according to the temperature of the engine clutch; Controlling the engine clutch by setting the engine rotational speed higher than the normal flat running mode when the engine clutch is fully engaged by switching to the HEV mode; And controlling the hybrid vehicle. 6. The method of claim 5, Wherein the temperature of the engine clutch is calculated by applying the conditions of the engine clutch operating oil temperature, the slip temperature of the engine clutch, and the cooling temperature. 6. The method of claim 5, Wherein the slip control hydraulic pressure amount of the engine clutch adjusts the hydraulic pressure gain according to the difference between the current revolution speed of the engine and the required idle revolution speed and the difference between the maximum output torque of the engine and the present output torque. Control method. 6. The method of claim 5, The slip control oil pressure amount of the engine clutch increases the gain of the oil pressure amount when the current revolution number of the engine is larger than the required idle revolution number, And the gain of the hydraulic pressure amount is decreased when the current number of revolutions of the engine is smaller than the required idle revolutions.

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