Apparatus and method for learning touch point of engine clutch of hybrid electric vehicle

Patent metadata

Field	Value
Publication number	US-9926989-B2
Application number	US-201514924157-A
Country	US
Kind code	B2
Filing date	Oct 27, 2015
Priority date	Jul 8, 2015
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

An apparatus and a method are provided for learning a touch point of an engine clutch of a hybrid electric vehicle that learns the touch point of the engine clutch based on a change of an engine torque while the hybrid electric vehicle is running. The method includes determining whether an engine clutch coupling after shifting is required and whether a learning condition based on a running state of the hybrid electric vehicle is satisfied when the engine clutch coupling after shifting is required. A coupling pressure of the engine clutch is increased when the learning condition is satisfied and a changing amount of an engine torque based on the increased coupling pressure of the engine clutch is compared with a predetermined value. The touch point of the engine clutch is learned when the changing amount of the engine torque is greater than or equal to the predetermined value.

First claim

What is claimed is:

1. A method for learning a touch point of an engine clutch of a hybrid electric vehicle having a motor connected to a transmission and an engine selectively connected to the motor via the engine clutch, comprising:
determining, by a controller, whether an engine clutch coupling after shifting is required;
determining, by the controller, whether a learning condition based on a running state of the hybrid electric vehicle is satisfied when the engine clutch coupling after shifting is required;
increasing, by the controller, a coupling pressure of the engine clutch when the learning condition is satisfied;
comparing, by the controller, a changing amount of an engine torque based on the increased coupling pressure of the engine clutch with a predetermined value; and
learning, by the controller, the touch point of the engine clutch when the changing amount of the engine torque is greater than or equal to the predetermined value,
wherein the engine clutch coupling after shifting is required when a demand torque of a driver is greater than or equal to a predetermined torque and a current motor speed is less than or equal to a target speed after shifting in consideration of discharging power of a battery.

2. The method of claim 1 , wherein the learning condition is satisfied when a battery state of charge (SOC) is within a predetermined range, a shifting state is a drive (D) stage, and the hybrid electric vehicle is shifting.

3. The method of claim 1 , wherein the coupling pressure of the engine clutch is increased by a signal rating which has an increasing form.

4. The method of claim 1 , further comprising:
after learning the touch point of the engine clutch, determining, by the controller, whether an engine speed is synchronized with a motor speed; and
coupling, by the controller, the engine clutch when the engine speed is synchronized with the motor speed.

5. An apparatus for learning a touch point of an engine clutch of a hybrid electric vehicle having a motor connected to a transmission and an engine selectively connected to the motor through the engine clutch, comprising:
a driving information detector configured to detect a running state of the hybrid electric vehicle; and
a controller configured to couple or release the engine clutch based on a signal from the driving information detector,
wherein the controller is configured to determine whether a learning condition is satisfied when an engine clutch coupling after shifting is required and learn the touch point of the engine clutch by increasing a coupling pressure of the engine clutch when the learning condition is satisfied,
wherein the controller is configured to compare a changing amount of an engine torque based on the increased coupling pressure of the engine clutch with a predetermined value, and learn the touch point of the engine clutch when the changing amount of the engine torque is greater than or equal to the predetermined value, and
wherein the controller is configured to determined that the engine clutch coupling after shifting is required when a demand torque of a driver is greater than or equal to a predetermined torque and a current motor speed is less than or equal to a target speed after shifting in consideration of discharging power of a battery.

6. The apparatus of claim 5 , wherein the controller is configured to determine that the learning condition is satisfied when a battery state of charge (SOC) is within a predetermined range, a shifting state is a drive (D) stage, and the hybrid electric vehicle is shifting.

7. The apparatus of claim 5 , wherein the controller is configured to increase the coupling pressure of the engine clutch through a signal rating which has an increasing form.

8. The apparatus of claim 5 , wherein the engine clutch includes a dry engine clutch.

9. The apparatus of claim 5 , wherein the controller is configured to couple the engine clutch when an engine speed is synchronized with a motor speed after learning the touch point of the engine clutch.

10. The apparatus of claim 5 , wherein the driving information detector includes a vehicle speed sensor, a motor speed sensor, an engine speed sensor, and an accelerator pedal position sensor (APS).

11. A non-transitory computer readable medium containing program instructions executed by a controller for learning a touch point of an engine clutch of a hybrid electric vehicle having a motor connected to a transmission and an engine selectively connected to the motor via the engine clutch, the computer readable medium comprising:
program instructions that determine whether an engine clutch coupling after shifting is required;
program instructions that determine whether a learning condition based on a running state of the hybrid electric vehicle is satisfied when the engine clutch coupling after shifting is required;
program instructions that increase a coupling pressure of the engine clutch when the learning condition is satisfied;
program instructions that compare a changing amount of an engine torque based on the increased coupling pressure of the engine clutch with a predetermined value; and
program instructions that learn the touch point of the engine clutch when the changing amount of the engine torque is greater than or equal to the predetermined value,
wherein the engine clutch coupling after shifting is required when a demand torque of a driver is greater than or equal to a predetermined torque and a current motor speed is less than or equal to a target speed after shifting in consideration of discharging power of a battery.

12. The non-transitory computer readable medium of claim 11 , wherein the learning condition is satisfied when a battery state of charge (SOC) is within a predetermined range, a shifting state is a drive (D) stage, and the hybrid electric vehicle is shifting.

13. The non-transitory computer readable medium of claim 11 , wherein the coupling pressure of the engine clutch is increased by a signal rating which has an increasing form.

14. The non-transitory computer readable medium of claim 11 , further comprising:
program instructions that determine whether an engine speed is synchronized with a motor speed after learning the touch point of the engine clutch; and
program instructions that couple the engine clutch when the engine speed is synchronized with the motor speed.

Assignees

• Hyundai Motor Co Ltd

Inventors

• Kim Do Hee
• Park Joonyoung

Classifications

• B60W2510/0657

  Engine torque · CPC title

• B60W20/40 Primary

  Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers {(power-up or power-down of the driveline B60W30/192)} · CPC title

• B60W10/06

  including control of combustion engines · CPC title

• B60W10/02

  including control of driveline clutches · CPC title

• B60K2006/4825

  Electric machine connected or connectable to gearbox input shaft · CPC title