Method for adjusting the damping force in motor vehicles in dependence on output signals of an acceleration transmitter

• US 4,805,101 A
• Filed: 09/25/1987
• Issued: 02/14/1989
• Est. Priority Date: 09/27/1986
• Status: Expired due to Term

• Current Assignee: BMW AG (Bayerische Motoren Werke AG)
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: Dietrich, Christian, Pfeil, Dirk, Hennecke, Dieter, Losch, Simon
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): MIS, DAVID C
• Application Number:
  US07/100,894
• Time in Patent Office: 508 Days
• Field of Search: 364/424, 280/688, 280/707
• US Class Current: 701/37
• CPC Class Codes: B60G 17/018 characterised by the use of a specific signal treatment or control method
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/60 Load
• CPC Class Codes: B60G 2400/7162 Fluid damper
• CPC Class Codes: B60G 2400/821 Uneven, rough road sensing affecting vehicle body vibration
• CPC Class Codes: B60G 2400/91 Frequency
• CPC Class Codes: B60G 2500/30 Height or ground clearance
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2600/12 Sampling or average detecting; Addition or substraction
• CPC Class Codes: B60G 2800/162 Reducing road induced vibrations

Abstract

A method for the damping force adjustment of motor vehicles in dependence on output signals of an acceleration transmitter connected with the vehicle body which are prepared and compared with a predetermined threshold value and which trigger a signal for changing the damping, respectively, spring force when exceeding, respectively, falling below the threshold value. An output signal of an acceleration transmitter rigidly connected with the vehicle body is slidingly determined over a first and a second measuring period, the difference of the two average values are subtracted from one another and are compared with the threshold value. The measuring periods are thereby larger, respectively, smaller than the natural period (reciprocal natural frequency) of the vehicle body.

Claims

1. A method for adjusting the damping force of motor vehicles in dependence on output signals of a transmitter arranged at a vehicle body, which are processed and which trigger a signal for changing the damping force when exceeding or dropping below a predetermined threshold value, comprising the steps of subtracting from one another average values formed from the output signals of a transmitter directly picking up the accelerations of the vehicle body, and comparing the numerical difference with a threshold value whereby the average values correspond to a first measuring period which is larger, respectively, to a second measuring period which is smaller than the natural period (reciprocal natural frequency) of the vehicle body.

2. A method according to claim 1, wherein the threshold value is dependent on at least one of vehicle velocity, load of the vehicle and damping oil temperature in case of hydraulic dampers.

3. A method according to claim 2, wherein the average values are obtained by averaging over measuring periods which are larger, respectively, smaller than the natural period of the vehicle body.

4. A method according to claim 2, wherein the average values are determined with the assistance of weighted actual output signals of the transmitter whereby the ratio of the weighting factors for the average values is substantially reciprocal to the ratio of the determining measuring periods.

5. A method according to claim 1, wherein the average values are obtained by averaging over measuring periods which are larger, respectively, smaller than the natural period of the vehicle body.

6. A method according to claim 1, wherein the average values are determined with the assistance of weighted actual output signals of the transmitter whereby the ratio of the weighting factors for the average values is substantially reciprocal to the ratio of the determining measuring periods.

7. A method according to claim 1, wherein the threshold value is dependent on vehicle velocity, load of the vehicle and damping oil temperature in case of hydraulic dampers.