Method for operating an electromechanical camshaft phaser

Patent metadata

Field	Value
Publication number	US-2022220870-A1
Application number	US-202017612655-A
Country	US
Kind code	A1
Filing date	May 20, 2020
Priority date	May 20, 2019
Publication date	Jul 14, 2022
Grant date	—

Abstract

An electromechanical camshaft phaser ( 3 ) comprises a setting gear ( 4 ) and an electric motor ( 5 ), which is controlled by means of an electric-motor control unit ( 6 ). Data concerning the operation of the electric motor ( 5 ) including position changes of its motor shaft are transferred via a data bus ( 8 ) from the electric-motor control unit ( 6 ) to an engine control unit ( 7 ) of the internal combustion engine ( 1 ) comprising the camshaft phaser ( 3 ). In addition, recurring time signals are transferred from the electric-motor control unit ( 6 ) to the engine control unit ( 7 ) via a separate line ( 9 ), by which harder real-time requirements are met than by the data bus ( 8 ). The time signals are used to generate a time difference signal in the engine control unit ( 7 ) by comparison with the data received by the engine control unit ( 7 ), which time difference signal is fed back to the electric-motor control unit ( 6 ) via the data bus ( 8 ) and is used there to synchronize the electric-motor control unit ( 6 ) with the engine control unit ( 7 ).

First claim

What is claimed is:

1 . A method for operating an electromechanical camshaft phaser, the electromechanical camshaft phaser comprising a setting gear and an electric motor provided for actuating the setting gear, which is controlled by an electric-motor control unit, the method comprising:
transmitting data concerning the operation of the electric motor, including position changes of a motor shaft of the electric motor, via a data bus from the electric-motor control unit to an engine control unit of an internal combustion engine comprising the camshaft phaser; transmitting recurring time signals from the electric-motor control unit to the engine control unit via a separate line, by which harder real-time requirements are met than by the data bus; using the time signals to generate a time difference signal in the engine control unit by comparison with the data received by the engine control unit; feeding the time difference signal back to the electric-motor control unit via the data bus; and using the time difference signal in the electric-motor control unit to synchronize the electric-motor control unit with the engine control unit.

2 . The method according to claim 1 further comprising processing successive processes which relate to the camshaft phaser both in the electric-motor control unit and in the engine control unit; and recording the respective data on the processes in a ring memory integrated in the electric-motor control unit or in the engine control unit.

3 . The method according to claim 1 wherein each of the electric-motor control unit and the engine control unit includes a ring memory, the method further comprising evaluating the data stored in the ring memories, for the most part, within the electric-motor control unit.

4 . The method according to claim 1 , wherein the data recorded and transmitted by the electric-motor control unit comprises trigger signals which relate to a specific camshaft position and are provided with a time stamp.

5 . The method according to claim 4 , further comprising detecting the position changes of the rotor of the electric motor by Hall sensors.

6 . A device for controlling an internal combustion engine having at least one electromechanical camshaft phaser, the electromechanical camshaft phaser comprising a setting gear and an electric motor provided for actuating the setting gear, the device comprising:
an engine control unit for controlling the internal combustion engine; and an electric-motor control unit for controlling the electric motor, the engine control unit and the electric-motor control unit being programmed to:
transmit data concerning the operation of the electric motor, including position changes of a motor shaft of the electric motor, via a data bus from the electric-motor control unit to the engine control unit;
transmit recurring time signals from the electric-motor control unit to the engine control unit via a separate line;
use the recurring time signals to generate a time difference signal in the engine control unit by comparison with the data received by the engine control unit;
feeding the time difference signal back to the electric-motor control unit via the data bus; and
use the time difference signal in the electric-motor control unit to synchronize the electric-motor control unit with the engine control unit.

7 . The device is as recited in claim 6 , wherein the separate line has a lesser volume of data transmitted than the data bus.

8 . An internal combustion engine comprising:
an engine block; the device as recited in claim 6 ; the data bus; the separate line; and the electromechanical camshaft phaser comprising the setting gear and the electric motor provided for actuating the setting gear.

9 . The internal combustion engine as recited in claim 8 , wherein the data bus is configured to transmit data between the electric-motor control unit and the engine control unit and between the engine control unit and the engine block, and the separate lines is configured to transmit data between the electric-motor control unit and the engine control unit and between the electric-motor control unit and the electric motor.

10 . A method for operating an electromechanical camshaft phaser, the electromechanical camshaft phaser comprising a setting gear and an electric motor provided for actuating the setting gear, the electric motor being controlled by an electric-motor control unit, the method comprising:
transmitting data concerning the operation of the electric motor, including position changes of a motor shaft of the electric motor, via a data bus from the electric-motor control unit to an engine control unit of an internal combustion engine comprising the camshaft phaser; transmitting recurring time signals from the electric-motor control unit to the engine control unit via a separate line; using the recurring time signals to generate a time difference signal in the engine control unit by comparison with the data concerning the operation of the electric motor transmitted by the electric-motor control unit to the engine control unit; feeding the time difference signal back to the electric-motor control unit via the data bus; and using the time difference signal in the electric-motor control unit to synchronize the electric-motor control unit with the engine control unit.

11 . The method is as recited in claim 10 , wherein the separate line has a lesser volume of data transmitted than the data bus.

12 . The method as recited in claim 10 , wherein the recurring time signals are stored in a memory of the electric-motor control unit and a memory of the engine control unit, a timing of the time signals stored in the memory of the electric-motor control unit being offset from a timing of the time signals stored in the memory of the engine control unit by a time difference represented by the time difference signal.

13 . The method as recited in claim 10 , wherein time signals of the recurring time signals represent tasks to be processed by the electric-motor control unit, at least one of the tasks having a task duration, the time difference being less than half of the task duration.

14 . The method as recited in claim 10 , wherein the data concerning the operation of the electric motor includes detection of reference marks on the camshaft or a part that has a fixed angular relationship to the camshaft.

15 . The method as recited in claim 10 , wherein the data concerning the operation of the electric motor includes a direction of rotation of a setting shaft connected to the motor shaft of the electric motor.

16 . The method as recited in claim 10 , further comprising controlling the internal combustion engine using the synchronized electric-motor control unit and engine control unit.

17 . The method as recited in claim 10 , wherein each of the recurring time signals represent a task to be processed by the electric-motor control unit, the method further comprising controlling the electric motor via the electric-motor control unit to perform the task.

Assignees

• Schaeffler Technologies Ag

Inventors

• Riedl Tobias
• Karbacher Christian

Classifications

• F01L2013/111

  Camshafts position or phase · CPC title

• F01L2013/103

  Electric motors · CPC title

• F01L2001/3521

  Harmonic drive of flexspline type · CPC title

• F01L1/352 Primary

  using bevel or epicyclic gear · CPC title

• F01L2820/032

  Electric motors · CPC title