Damping of power train oscillations

• US 9,050,979 B2
• Filed: 02/21/2012
• Issued: 06/09/2015
• Est. Priority Date: 02/23/2011
• Status: Expired due to Fees

• Current Assignee: Scania CV AB (Volkswagen AG)
• Original Assignee: Scania CV AB (Volkswagen AG)
• Inventors: Lerede, Niclas, Flemmer, Henrik
• Primary Examiner(s): CHEUNG, CALVIN K
• Application Number:
  US13/984,901
• Publication Number:
  US 20130325277A1
• Time in Patent Office: 1,204 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 2050/0039 of the propulsion unit
• CPC Class Codes: B60W 2050/0056 Low-pass filters
• CPC Class Codes: B60W 2050/0057 Frequency analysis, spectral techniques or transforms
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 30/20 Reducing vibrations in the driveline
• CPC Class Codes: B60W 50/0098 Details of control systems ensuring comfort, safety or stability not otherwise provided for
• CPC Class Codes: F02D 2200/101 Engine speed
• CPC Class Codes: F02D 2200/1012 Engine speed gradient
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 2250/28 Control for reducing torsional vibrations, e.g. at acceleration
• CPC Class Codes: F02D 41/1498 measuring engine roughness

Abstract

A method for damping of a power train oscillation in a vehicle provided with a prime mover which delivers a torque related to a torque request M from a vehicle system and rotates at a speed ω. A cyclic variation S in the rotation speed ω of said prime mover is determined. The torque request M is then given an oscillation-damping characteristic by use of the cyclic variation S, making it possible for the power train oscillation to be effectively damped out.

Claims

1. A method for damping a power train oscillation in a vehicle provided with a prime mover, wherein the prime mover imparts a torque related to a torque request M provided to the prime mover from a controller and the prime mover rotates at a speed ω

;

the method further comprising;

determining with the controller a change in cyclic variation S in the rotation speed ω

of the prime mover; and

using the cyclic variation S in the controller to give the torque request M an oscillation-damping characteristic.

2. The method according to claim 1, further comprising wherein the torque request imparted is an original torque request determining the oscillation-damping characteristic by adding a change in the cyclic variation S, and multiplying the change by at least one amplification factor A₁, and adding the multiplied change to the original torque request M_o.

3. The method according to claim 2, wherein the original torque request M_o provided to the prime mover originates from at least one of,

an accelerator pedal;

and

a cruise control of the vehicle.

4. The method according to claim 1, further comprising determining the oscillation-damping torque request M only when the power train oscillation has been detected.

5. The method according to claim 4, further comprising detecting the power train oscillations on the basis of the change in cyclic variation S.

6. The method according to claim 5, wherein the detection is deemed to show that there is a power train oscillation if for a selected number of times the amplitude of the change in cyclic variation S is alternately above a positive threshold value Th₁ and below a negative threshold value Th₂ and if all of the consecutive upward crossings of the positive threshold value Th₁ and the connective downward crossings of the negative threshold value Th₂ are separated in time by not more than a predetermined period T.

7. The method according to claim 1, wherein the change in the cyclic variation S is based on the rotation speed ω

of the prime mover.

8. The method according to claim 7, wherein the rotation speed ω

comprises a desired rotation speed ω

_d and a superimposed cyclic variation.

9. The method according to claim 8, further comprising determining the desired rotation speed ω

_d by filtering the rotation speed ω

.

10. The method according to claim 8, further comprising determining an inverted version of the superimposed cyclic variation ω

_s by subtracting the rotation speed ω

from the desired rotation speed ω

_d.

11. The method according to claim 10, further comprising determining the change in cyclic variation S by time derivation of the inverted version of the superimposed cyclic variation ω

_s.

12. The method according to claim 8, further comprising determining an inverted version of the superimposed cyclic variation ω

_s by a model of the inverted version of the superimposed cyclic variation ω

_s.

13. The method according to claim 1, further comprising determining the rotation speed ω

by at least one of a sensor configured for detecting the rotation speed ω

; and

a model for the rotation speed ω

.

14. A non-transitory computer readable medium encoded with a computer program for damping of a power train oscillation in a vehicle provided with a prime mover such that when the program code is executed in a computer, the execution causes the computer to

determine a change in cyclic variation S in the rotation speed w of the primer mover;

and

use the cyclic variation S to give a torque request M to the primer mover with an oscillation damping characteristic.

15. A system for damping a power train oscillation in a vehicle provided with a prime mover, wherein the prime mover is configured to impart a torque related to a torque request M provided to the prime mover, the prime mover rotates at a speed ω

;

the system further comprises;

a determination unit configured for determining a change in cyclic variation S in the rotation speed co of the prime mover; and

a torque unit configured for using the change in the cyclic variation S to give the torque request Man oscillation-damping characteristic.

16. The system according to claim 15, wherein the torque unit is configured for adding the change in cyclic variation S, multiplied by at least one amplification factor A₁, to an original torque request M_o, to the prime mover for obtaining the oscillation-damping characteristic.