DAMPING FORCE CONTROL APPARATUS FOR VEHICLE

Abstract

A damping force control apparatus for a vehicle includes adjustable-damping-force shock absorbers. When the vehicle turns, an electronic controller calculates an actual roll angle of the vehicle body in accordance with sprung accelerations detected by sprung acceleration sensors. The electronic controller also calculates a target roll angle of the vehicle body in accordance with a lateral acceleration detected by a lateral acceleration sensor. The target roll angle is set such that it increases with the lateral acceleration acting on the vehicle during turning and is uniquely determined by the lateral acceleration. The electronic controller sets target damping forces of the shock absorbers such that the actual roll angle coincides with the target roll angle, and controls the damping forces of the shock absorbers in accordance with the set target damping forces.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, features and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description of the preferred embodiments when considered in connection with the accompanying drawings, in which:

FIG. 1 is a schematic diagram relating to first to third embodiments of the present invention and modifications of the first embodiment, and showing the overall configuration of a damping force control apparatus for a vehicle;

FIG. 2 is a flowchart relating to the first to third embodiments and the modifications of the first embodiment, and showing a roll control program executed by an electronic controller shown in FIG. 1;

FIG. 3 is a flowchart relating to the first to third embodiments and the modifications of the first embodiment, and showing an actual roll-angle calculation program executed by the electronic controller shown in FIG. 1;

FIG. 4 is a graph relating to the first to third embodiments and the modifications of the first embodiment, and showing a change in target roll angle with lateral acceleration, which is stored in a target roll angle table provided in the electronic controller;

FIG. 5 is a graph relating to the first to third embodiments and the modifications of the first embodiment, and showing a change in damping force with stroke speed, which is stored in a damping force table provided in the electronic controller;

FIG. 6 is a flowchart relating to the second and third embodiments, and showing a pitching control program executed by the electronic controller shown in FIG. 1;

FIG. 7 is a flowchart relating to the second and third embodiments, and showing an actual pitch-angle calculation program executed by the electronic controller shown in FIG. 1;

FIG. 8 is a graph relating to the second and third embodiments, and showing a change in target pitch angle with target roll angle, which is stored in a target pitch angle table provided in the electronic controller; and

FIG. 9 is a flowchart relating to the third embodiment, and showing a damping force control program executed by the electronic controller shown in FIG. 1.

Claims

1. A damping force control apparatus for a vehicle in which four wheels are suspended by respective suspension systems including respective shock absorbers, and damping forces of the shock absorbers are controlled individually in accordance with turning conditions of the vehicle, the damping force control apparatus comprising: posture detection means for detecting the posture of the vehicle during turning;lateral acceleration detection means for detecting a lateral acceleration acting on the vehicle during turning;target-posture setting means for setting a target posture of the vehicle body during turning in accordance with the lateral acceleration detected by the lateral acceleration detection means;target-damping-force setting means for setting target damping forces which the shock absorbers are required to generate so as to render the posture of the vehicle body detected by the posture detection means coincident with the target posture set by the target-posture setting means; anddamping-force control means for controlling the damping forces of the shock absorbers in accordance with the target damping forces set by the target-damping-force setting means.

2. A damping force control apparatus for a vehicle according to claim 1, wherein the posture detection means detects an actual roll angle of the vehicle body about a longitudinal axis of the vehicle, and the target-posture setting means sets a target roll angle of the vehicle body about the longitudinal axis which increases with the detected lateral acceleration and is uniquely determined by the lateral acceleration.

3. A damping force control apparatus for a vehicle according to claim 1, wherein the posture detection means detects an actual pitch angle of the vehicle body about a lateral axis of the vehicle, and the target-posture setting means sets a target pitch angle of the vehicle body about the lateral axis which increases with the detected lateral acceleration and is uniquely determined by the lateral acceleration.

4. A damping force control apparatus for a vehicle according to claim 1, wherein the posture detection means detects an actual roll angle of the vehicle body about a longitudinal axis of the vehicle and an actual pitch angle of the vehicle body about a lateral axis of the vehicle, and the target-posture setting means sets a target roll angle of the vehicle body about the longitudinal axis which increases with the detected lateral acceleration and is uniquely determined by the lateral acceleration and a target pitch angle of the vehicle body about the lateral axis which increases with the detected lateral acceleration and is uniquely determined by the lateral acceleration.

5. A damping force control apparatus for a vehicle according to claim 1, wherein the target-damping-force setting means includes: jack-up-force calculation means for calculating a jack-up force acting from the suspension systems to the vehicle body during turning, and jack-up-corresponding-target-damping-force calculation means for calculating the target damping forces in consideration of the Jack-up force calculated by the jack-up-force calculation means.