Control structure for the adjusting motor of an electric camshaft adjuster

• US 20060124095A1
• Filed: 02/08/2006
• Published: 06/15/2006
• Est. Priority Date: 07/11/2002
• Status: Active Grant

• Current Assignee: Schaeffler Technologies AG & Co.KG (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: INA-Schaeffler KG
• Inventors: Overberg, Martin, Steigerwald, Martin, Schafer, Jens
• Granted Patent: US 7,152,561 B2
• Time in Patent Office: Days
• US Class Current: 123/90.170
• CPC Class Codes: F01L 1/022 Chain drive
• CPC Class Codes: F01L 1/024 Belt drive
• CPC Class Codes: F01L 1/34 characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
• CPC Class Codes: F01L 1/344 changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
• CPC Class Codes: F01L 1/352 using bevel or epicyclic gear
• CPC Class Codes: F01L 2800/00 Methods of operation using a variable valve timing mechanism
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2041/141 using a feed-forward control element
• CPC Class Codes: F02D 2041/1419 the control loops being cascaded, i.e. being placed in series or nested
• CPC Class Codes: Y10T 74/2102 Adjustable

Abstract

A control structure for the adjusting motor of an electric camshaft adjuster in an internal combustion engine is provided. The control structure includes a controller which processes measuring signals of the internal combustion engine to control data for the adjusting motor. A controller which has meaningful values for the adjusted setpoint rotational speed of the adjusting motor, even when the input differential signal has a zero value, is obtained by applying the signal of an uncontrolled rotational speed to the output signal of a controlled setpoint rotational speed.

Claims

1. Control structure for achieving a desired adjusted rotational speed in an adjusting motor of an electric camshaft adjuster for the camshaft of an internal combustion engine, comprising:

the camshaft adjuster comprising an adjusting gear unit, which is configured as a triple-shaft gear system, with a drive shaft, which is connected to the camshaft drive wheel, a driven shaft, which is connected to the camshaft, and an adjusting shaft, which is connected to a rotor of the adjusting motor

the adjusting motor having a stator, which is provided fixed to a housing,

the camshaft adjuster having at least one controller, which generates control signals for the adjusting motor from measurement signals of the internal combustion engine, an input signal of the controller is a difference signal derived from a desired and an actual value and an output signal is a controlled desired adjusted rotational speed signal defined for the adjusting motor, to which an uncontrolled rotational speed signal, which corresponds to the camshaft rotational speed, is added.

2. Control structure according to claim 1, wherein a position control, which refers to the camshaft adjusted angle, and also rotational speed control, which refers to the adjusting motor rotational speed, are provided.

3. Control structure according to claim 2, wherein the controllers for the position and rotational speed control comprise at least one of a P, PI, PID, prediction or monitoring controllers.

4. Control structure according to claim 3, wherein a prediction controller sets an adjusted rotational speed that can be delayed by the adjusting motor in an available time period, depending on an appropriate adjusted angle jump of the camshaft.

5. Control structure according to claim 4, wherein for the position control a prediction controller is provided and for the rotational speed control a PID controller is provided, which can be used individually or connected in series.

6. Control structure according to claim 5, wherein for position control, the input signal of the prediction controller is the difference signal between an actual adjusted angle and a desired adjusted angle of the camshaft and the output signal is a controlled desired adjusted rotational speed for the adjusting motor and that the added rotational speed is the camshaft rotational speed.

7. Control structure according to claim 5, wherein for rotational speed control, the input signal of the PID controller is the difference signal between an actual adjusted rotational speed and a desired adjusted rotational speed of the adjusting motor and the output signal is a controlled desired adjusted rotational speed for the adjusting motor in the form of a voltage value or a pulse-duty-factor modulated voltage and that the added rotational speed is an uncontrolled and voltage-converted desired adjusted rotational speed of the adjusting motor.

8. Control structure according to claim 5, wherein for a series connection of the prediction controller and the PID controller, the output signal of the prediction controller with added camshaft rotational speed in the voltage-converted form is also used as an application signal for the output signal of the PID controller.

9. Control structure according to claim 8, wherein the PID controller of the rotational speed control has a current limiting function comprising a two-position current regulator.

10. Control structure according to claim 1, wherein the position of the angle of rotation of the camshaft can be measured by a camshaft sensor or by a Hall sensor of the adjusting motor.