DAMPING OF POWER TRAIN OSCILLATIONS

• US 20130325277A1
• Filed: 02/21/2012
• Published: 12/05/2013
• Est. Priority Date: 02/23/2011
• Status: Active Grant

• Current Assignee: Scania CV AB (Volkswagen AG)
• Original Assignee: Scania CV AB (Volkswagen AG)
• Inventors: Lerede, Niclas, Flemmer, Henrik
• Granted Patent: US 9,050,979 B2
• Time in Patent Office: Days
• US Class Current: 701/70
• 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 and the prime mover rotates at a speed ω

;

the method further comprising;

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

of the prime mover; and

using the cyclic variation S for giving the torque request Man oscillation-damping characteristic.

2. A 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. A method according to claim 2, wherein the original torque request M_o provided to the prime mover originates from

an accelerator pedal;

and/or

a cruise control of the vehicle.

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

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

6. A 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. A 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. A method according to claim 7, wherein the rotation speed ω

comprises a desired rotation speed ω

_d and a superimposed cyclic variation.

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

_d by filtering the rotation speed ω

.

10. A 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. A 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.

12. A 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.

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

by a sensor configured for detecting the rotation speed ω

; and

/or by 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 apply the method according to claim 1.

15. A computer program product comprising a computer-readable medium with a computer program according to claim 14 and the program is contained in the computer-readable medium.

16. 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 ω

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.

17. A system according to claim 16, 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.