System and method for controlling engine clutch of hybrid vehicle

1. A system for controlling an engine clutch of a hybrid vehicle, comprising:

a sensor configured to sense whether the engine clutch is released in a transfer from a hybrid electric vehicle (HEV) mode to an electric vehicle (EV) mode;

a first motor torque controller configured to adjust a motor torque in a transfer section to be changed to a level where the acceleration of the vehicle before and after the release of the engine clutch is maintained substantially constant, in response to determining that the engine clutch has been released; and

a second motor torque controller configured to adjust the motor torque in the transfer section to the level of a driver request torque in the EV mode,

wherein the first motor torque controller is configured to calculate the motor torque in the transfer section at a level where a change in acceleration of an engine clutch rear part is prevented, in consideration that inertia is changed from Inertia of the engine clutch part (J1)+Inertia of the engine clutch rear part (J2) to Inertia of the engine clutch rear part (J2).

2. The system of claim 1 , wherein the first motor torque controller is configured to calculate the motor torque in the transfer section at a level where a change in acceleration of an engine clutch rear part is prevented from an equation considering inertia before and after the release of the engine:

ω

.

m

EV

=

ω

.

m

HEV

⁢

:

⁢

T

Motor

EV

J

2

=

T

HSG

HEV

+

T

Engine

HEV

+

T

Motor

HEV

J

1

+

J

2

⁢

⇒

T

Motor

EV

=

J

2

J

1

+

J

2

⁢

(

T

HSG

HEV

+

T

Engine

HEV

+

T

Motor

HEV

)

,

and

wherein, in the above equation,

J 1 : Inertia of the engine clutch front part

J 2 : Inertia of the engine clutch rear part

{dot over (ω)} m HEV : Motor acceleration in the HEV mode

{dot over (ω)} m EV : Motor acceleration in the EV mode

T HSG HEV : HSG torque in the HEV mode

T Engine HEV : Engine torque in the HEV mode

T Motor HEV : Motor torque in the HEV mode

T Motor EV : Motor torque in the EV mode.

3. The system of claim 1 , wherein the second motor torque controller is configured to:

calculate a blended motor torque obtained by blending the driver request torque and the motor torque in the transfer section, adjusted to be decreased by the first motor torque controller, and gradually increase or decrease the motor torque in the transfer section to the level of the driver request torque while commanding the calculated blended motor torque to a motor; and

calculate that the blended motor torque is substantially similar to the driver request torque to stop commanding the blended motor torque to the motor.

4. A method for controlling an engine clutch of a hybrid vehicle, the method comprising:

identifying, by a sensor, whether the engine clutch is released in transfer from a hybrid electric vehicle (HEV) mode to an electric vehicle (EV) mode;

adjusting, by a first controller, a motor torque in a transfer section to a level where the acceleration of the vehicle before and after the release of the engine clutch is maintained substantially constant, in response to determining that the engine clutch has been released; and

adjusting, by a second controller, the motor torque in the transfer section to the level of a driver request torque in the EV mode,

wherein the motor torque is calculated by the first controller in the transfer section at a level where a change in acceleration of an engine clutch rear part is prevented, in consideration that inertia is changed from Inertia of the engine clutch part (J1)+Inertia of the engine clutch rear part (J2) to Inertia of the engine clutch rear part (J2).

5. The method of claim 4 , wherein the motor torque in the transfer section is adjusted to be decreased to a level where a change in acceleration of an engine clutch rear part is prevented.

6. The method of claim 5 , wherein the motor torque in the transfer section is calculated by an equation considering inertia before/after the release of the engine:

ω

.

m

EV

=

ω

.

m

HEV

⁢

:

⁢

T

Motor

EV

J

2

=

T

HSG

HEV

+

T

Engine

HEV

+

T

Motor

HEV

J

1

+

J

2

⁢

⇒

T

Motor

EV

=

J

2

J

1

+

J

2

⁢

(

T

HSG

HEV

+

T

Engine

HEV

+

T

Motor

HEV

)

,

and

wherein, in the above equation,

J 1 : Inertia of the engine clutch front part

J 2 : Inertia of the engine clutch rear part

{dot over (ω)} m HEV : Motor acceleration in the HEV mode

{dot over (ω)} m EV : Motor acceleration in the EV mode

T HSG HEV : HSG torque in the HEV mode

T Engine HEV : Engine torque in the HEV mode

T Motor HEV : Motor torque in the HEV mode

T Motor EV : Motor torque in the EV mode.

7. The method of claim 4 , further comprising:

calculating, by the second controller, a blended motor torque obtained by blending the driver request torque and the motor torque in the transfer section, adjusted to be decreased by the first controller, and gradually increase or decrease the motor torque in the transfer section to the level of the driver request torque while commanding the calculated blended motor torque to a motor; and

commanding, by the second controller, the blended motor torque to the motor, when the blended motor torque is substantially similar to the driver request torque.

8. The method of claim 7 , wherein the driver request torque and the motor torque in the transfer section, adjusted to be decreased by the first controller, are blended using a weighting factor.

9. A non-transitory computer readable medium containing program instructions executed by a controller, the computer readable medium comprising:

program instructions that control a sensor to identify whether the engine clutch is released in transfer from a hybrid electric vehicle (HEV) mode to an electric vehicle (EV) mode;

program instructions that adjust a motor torque in a transfer section to a level where the acceleration of the vehicle before and after the release of the engine clutch is maintained substantially constant, in response to determining that the engine clutch has been released; and

program instructions that adjust the motor torque in the transfer section to the level of a driver request torque in the EV mode,

wherein the motor torque is calculated in the transfer section at a level where a change in acceleration of an engine clutch rear part is prevented, in consideration that inertia is changed from Inertia of the engine clutch part (J1)+Inertia of the engine clutch rear part (J2) to Inertia of the engine clutch rear part (J2).

10. The non-transitory computer readable medium of claim 9 , wherein the motor torque in the transfer section is adjusted to be decreased to a level where a change in acceleration of an engine clutch rear part is prevented.

11. The non-transitory computer readable medium of claim 9 , wherein the motor torque in the transfer section is calculated by an equation considering inertia before/after the release of the engine:

ω

.

m

EV

=

ω

.

m

HEV

⁢

:

⁢

T

Motor

EV

J

2

=

T

HSG

HEV

+

T

Engine

HEV

+

T

Motor

HEV

J

1

+

J

2

⁢

⇒

T

Motor

EV

=

J

2

J

1

+

J

2

⁢

(

T

HSG

HEV

+

T

Engine

HEV

+

T

Motor

HEV

)

,

and

wherein, in the above equation,

J 1 : Inertia of the engine clutch front part

J 2 : Inertia of the engine clutch rear part

{dot over (ω)} m HEV : Motor acceleration in the HEV mode

{dot over (ω)} m EV : Motor acceleration in the EV mode

T HSG HEV : HSG torque in the HEV mode

T Engine HEV : Engine torque in the HEV mode

T Motor HEV : Motor torque in the HEV mode

T Motor EV : Motor torque in the EV mode.