Apparatus and method for controlling engine clutch

Patent metadata

Field	Value
Publication number	US-2016137191-A1
Application number	US-201514751244-A
Country	US
Kind code	A1
Filing date	Jun 26, 2015
Priority date	Nov 19, 2014
Publication date	May 19, 2016
Grant date	—

Abstract

A method and an apparatus for controlling an engine clutch are provided. The method includes determining whether an engine start condition is satisfied when an engine is stopped and performing an engine cranking operation by operating a hybrid starter & generator (HSG) when the engine start condition is satisfied. Whether an engine speed is greater than or equal to a first reference speed is determined to thus reduce an HSG torque. Then, whether the engine speed is greater than or equal to a second reference speed is determined to thus calculate a target speed of the engine. A speed control of the engine is performed using the target speed of the engine while determining whether an engine clutch engagement condition is satisfied. An engine clutch is engaged when the engine clutch engagement condition is satisfied.

First claim

What is claimed is:

1 . A method for controlling an engine clutch, comprising:
determining, by a controller, whether an engine start condition is satisfied when an engine is stopped; performing, by the controller, an engine cranking operation by operating a hybrid starter & generator (HSG) when the engine start condition is satisfied; determining, by the controller, whether an engine speed is greater than or equal to a first reference speed; reducing, by the controller, an HSG torque when the engine speed is greater than or equal to the first reference speed; determining, by the controller, whether the engine speed is greater than or equal to a second reference speed; calculating, by the controller, a target speed of the engine when the engine speed is greater than or equal to the second reference speed; performing, by the controller, speed control of the engine using the target speed of the engine; determining, by the controller, whether an engine clutch engagement condition is satisfied while performing the speed control; and engaging, by the controller, an engine clutch when the engine clutch engagement condition is satisfied.

2 . The method of claim 1 , wherein the performing of the engine cranking operation by operating the HSG includes:
increasing, by the controller, the engine speed by maintaining a maximum HSG torque.

3 . The method of claim 2 , further comprising:
continuously maintaining, by the controller, the maximum HSG torque when the engine speed is less than the first reference speed.

4 . The method of claim 1 , wherein the calculating the target speed of the engine includes:
calculating, by the controller, initial offset based on the second reference speed and a motor speed when the engine speed reaches the second reference speed; dividing, by the controller, the initial offset to generate an offset input; and interpolating, by the controller, the offset input to generate an interpolated offset input.

5 . The method of claim 4 , wherein the dividing the initial offset to generate the offset input includes:
dividing, by the controller, a range from zero to the initial offset into a plurality of sub-ranges; determining, by the controller, a slope that corresponds to the respective sub-ranges; and generating, by the controller, the offset input increased with the determined slope.

6 . The method of claim 4 , wherein the dividing the initial offset to generate the offset input includes:
calculating, by the controller, a first value that corresponds to a first preset ratio of the initial offset; calculating, by the controller, a second value that corresponds to a second preset ratio of the initial offset; generating, by the controller, the offset input increased with respect to a first slope until the offset input reaches the first value from zero; when the offset input reaches the first value, generating, by the controller, the offset input increased with respect to a second slope until the offset input reaches the second value from the first value; and when the offset input reaches the second value, generating, by the controller, the offset input increased with respect to a third slope until the offset input reaches the initial offset from the second value.

7 . The method of claim 6 , wherein the first slope is determined by considering a slope of the engine speed when the engine speed reaches the second reference speed.

8 . The method of claim 6 , wherein the second slope Δ 2 is determined by considering the first slope among values satisfying an equation of:

Δ
2

≤

Max



T



Q

J

,

wherein the MaxTQ is a maximum torque that a torque source including the engine and the HSG outputs in a current running state, and the J is inertia of an input shaft of the engine clutch.

9 . The method of claim 6 , wherein the third slope is determined by considering the second slope and a slope of the motor speed.

10 . The method of claim 4 , wherein the dividing the initial offset to generate the offset input includes:
determining, by the controller, a target time when engaging of the engine clutch is completed based on the initial offset; dividing, by the controller, an interval from the time when the engine speed reaches the second reference speed to the target time into a plurality of sub-intervals; determining, by the controller, a slope that corresponds to the respective sub-intervals; and generating, by the controller, the offset input increased with the determined slope.

11 . The method of claim 10 , wherein the plurality of sub-intervals include a first sub-interval, a second sub-interval, and a third sub-interval, and
a first slope that corresponds to the first sub-interval is determined by considering a slope of the engine speed when the engine speed reaches the second reference speed.

12 . The method of claim 11 , wherein a second slope Δ 2 that corresponds to the second sub-interval is determined by considering the first slope among values satisfying an equation of

Δ
2

≤

Max



T



Q

J

,

wherein the MaxTQ is a maximum torque that a torque source including the engine and the HSG outputs in a current running state, and the J is inertia of an input shaft of the engine clutch.

13 . The method of claim 12 , wherein a third slope that corresponds to the third sub-interval is determined by considering the second slope and a slope of the motor speed.

14 . The method of claim 4 , wherein the calculating the target speed of the engine further includes:
calculating, by the controller, a difference between the motor speed and the initial offset; and adding, by the controller, the interpolated offset input to the difference between the motor speed and the initial offset.

15 . The method of claim 1 , wherein the performing of the speed control of the engine includes:
calculating, by the controller, a difference between the target speed of the engine and a current speed of the engine; calculating, by the controller, feedback control input using the difference between the target speed of the engine and the current speed of the engine; calculating, by the controller, feed-forward control input using inertia of an input shaft of the engine clutch and the target speed of the engine; calculating, by the controller, disturbance control input using a nominal inverse model and at least one low pass filter based on t

Assignees

• Hyundai Motor Co Ltd

Inventors

• Bang Jae Sung

Classifications

• B60W2050/0056

  Low-pass filters · 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

• B60K6/48

  Parallel type · CPC title

• B60W2510/06

  Combustion engines, Gas turbines · CPC title

• F02D41/062

  for starting (F02D41/061 takes precedence) · CPC title