Method and control device for adjusting the damping force of a shock absorber

Patent metadata

Field	Value
Publication number	US-10696121-B2
Application number	US-201715825582-A
Country	US
Kind code	B2
Filing date	Nov 29, 2017
Priority date	Dec 5, 2016
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

Method for adjusting the damping force of shock absorbers connected between a vehicle body and a wheel at vehicle corners of a motor vehicle, wherein at least one damping force (FLIFT, FPITCH, FROLL) which is referred to a center of gravity of the vehicle body and is divided between axles of the vehicle and between the shock absorbers of the axles is determined as a function of at least one variable which represents a movement of the vehicle body and/or a movement of the respective wheel. For at least one of the damping forces which are referred to the center of gravity of the vehicle body, at least one division factor for the division of the damping forces is calculated between a front axle and a rear axle, and the division of the respective damping force (FLIFT, FPITCH, FROLL) is adapted on the basis of this division factor.

First claim

What is claimed is:

1. A method for adjusting a damping force of shock absorbers connected between a vehicle body and a wheel at vehicle corners of a motor vehicle, comprising the steps of:
determining at least one damping force (F LIFT , F PITCH , F ROLL ), which is referred to a center of gravity of the vehicle body and is divided between axles of the motor vehicle and between shock absorbers of the axles as a function of at least one variable which represents a movement of the vehicle body or a movement of the respective wheel, calculating, for at least one of the damping forces which are referred to the center of gravity of the vehicle body, at least one division factor for the division of said damping forces between a front axle and a rear axle of the motor vehicle, and
adjusting the division of the respective damping force (F LIFT , F PITCH , F ROLL ) on the basis of the at least one division factor,
wherein the at least one division factor is calculated as a function of a lifting-spring stiffness of the front axle, a lifting-spring stiffness of the rear axle, a mass which loads the front axle and a mass which loads the rear axle.

2. The method as claimed in claim 1 , wherein, for all the damping forces referred to the center of gravity of the vehicle body, of lifting, pitching and rolling modal directions (F LIFT , F PITCH , F ROLL ), the method further comprises, in each case, calculating at least one division factor for the division of the respective damping force between the front axle and the rear axle, and adjusting the division of each damping force (F LIFT , F PITCH , F ROLL ) on the basis of the division factor.

3. The method as claimed in claim 2 , wherein the or each division factor for the lifting modal direction is calculated as a function of the lifting-spring stiffness of the front axle, the lifting-spring stiffness of the rear axle, the mass which loads the front axle and the mass which loads the rear axle.

4. The method as claimed in claim 3 , wherein division factors for the lifting modal direction are calculated as follows:

α

FA
⁢

-

⁢
LIFT

=

c

FA
⁢

-

⁢
LIFT

⁢

m
FA

c

FA
⁢

-

⁢
LIFT

⁢

m
FA

+

c

RA
⁢

-

⁢
LIFT

⁢

m
RA

,

⁢

α

RA
⁢

-

⁢
LIFT

=

c

RA
⁢

-

⁢
LIFT

⁢

m
RA

c

FA
⁢

-

⁢
LIFT

⁢

m
FA

+

c

RA
⁢

-

⁢
LIFT

⁢

m
RA

,

where
α FA-LIFT is the division factor for the front axle for the lifting modal direction,
α RA-LIFT is the division factor for the rear axle for the lifting modal direction,
C FA-LIFT is the lifting-spring stiffness of the front axle,
C RA-LIFT is the lifting-spring stiffness of the rear axle,
m FA is the mass which loads the front axle, and
m RA is the mass which loads the rear axle.

5. The method as claimed in claim 2 , wherein the or each division factor for the pitching modal direction is calculated as a function of a pitching-spring stiffness of the front axle, a pitching-spring stiffness of the rear axle, a pitching-moment of mass inertia which loads the front axle and a pitching-moment of mass inertia which loads the rear axle.

6. The method as claimed in claim 5 , wherein division factors for the pitching modal direction are calculated as follows:

α

FA
⁢

-

⁢
PITCH

Assignees

• Porsche Ag

Inventors

• Liebold Jochen
• Caredda David

Classifications

• B60G2400/0511

  Roll angle · CPC title

• B60G2400/0512

  Pitch angle · CPC title

• B60G2400/252

  vertical · CPC title

• B60G2800/70

  Estimating or calculating vehicle parameters or state variables · CPC title

• B60G17/06 Primary

  Characteristics of dampers {, e.g. mechanical dampers}(B60G17/015 takes precedence) · CPC title