Toyota Jidosha Kabushiki Kaisha

Aisin Seiki Kabushiki Kaisha

Kazuo Ogawa

Naoki Yamada

Shigetaka Isogai

Satoru Onozawa

Hirofumi Inoue

Hideo Inoue

Yoshikazu Tachiiri

Hiroaki Date

Yoshiaki Kanoh

A vehicle suspension system including: (a) a suspension spring interconnecting a vehicle body and a wheel; (b) an actuator having an electric motor, such that the actuator is capable of generating, based on a force of the electric motor, an actuator force forcing the body and the wheel toward and away from each other, and causing the generated actuator force to act as a damping force against displacement of the body and the wheel; and (c) a control device for controlling the actuator force generated by the actuator, by controlling operation of the electric motor. The control device is capable of establishing a constant-force generating state in which the actuator force is constantly generated as a constant actuator force by the actuator with supply of an electric power thereto from a battery as an electric power source of the electric motor such that the generated constant actuator force acts in a rebound direction or a bound direction. The control device controls the constant-force generating state, based on a charge state of the battery.

Vehicle suspension system

The presence or absence of any step-out of an actuator which is used to adjust a damping factor is made always detectable without additional provision of any special sensor such as a position encoder. Based on an equation of motion of a suspension, an estimated acceleration Gp derived from a detected vehicle height Sh and its differential Vr, and an actual acceleration Sg detected by an acceleration sensor, a deviation .DELTA.G is derived and compared against a threshold A. If the magnitude of the deviation is high, the occurrence of the step-out is declared after a given time interval T.sub.0. Upon detecting the occurrence of the step-out, the actuator position is returned to its home position, and the value in the position register is initialized. A skyhook control of the suspension is performed.

Apparatus for detecting step-out of suspension control system

A device for estimating a temperature of a working oil in a shock absorber in a suspension system which connects a sprung member and an unsprung member of a motor vehicle, wherein the temperature of the oil is estimated on the basis of at least detected vertical acceleration of the sprung member. The device may be suitably incorporated in an apparatus for controlling the damping characteristic of the shock absorber, wherein an actuator is operated by a controller for changing the damping characteristic, and the controller includes the temperature estimating device, and a device for inhibiting an operation of the actuator to control the damping characteristic when the oil temperature estimated by the temperature estimating device is lower than a predetermined threshold.

Oil temperature estimating device for shock absorber, and shock absorber

A vehicle height control system including a shock absorber having an air chamber, an air compressor connected with the shock absorber through an air supply conduit, an air drain conduit connected the air supply conduit, an air drain valve in the air drain conduit and which is opened so as to discharge to the atmosphere, air stored in the air chamber and the air supply conduit, a cut-off valve disposed between the shock absorber and the air compressor in the supply conduit and which is closed so as to store the air in the air chamber, and a controller which controls an operation of the air compressor, the air drain valve and the cut-off valve so as to control the amount of air stored in the air chamber, wherein the air drain valve remains opened for a predetermined time during which operation of the air compressor is started and the cut-off vale is opened after the air compressor is started.

Vehicle height control System

A suspension control apparatus comprises a sprung velocity measuring device for measuring a sprung velocity, a relative velocity measuring device for measuring a relative velocity between the sprung and unsprung velocities, a controller for mode-converting, weighting and inversely mode-converting the sprung velocity and relative velocity, and having a dead zone setting circuit for changing over a control value when the polarity of the velocity difference is inverted at a first time, in order to calculate a velocity ratio and determine a target damping force, and an actuator for controlling the opening area in the variable throttle mechanism communicating with the cylinder piston apparatus of absorber was disclosed. The suspension control apparatus has the effect that there is no delay in controlling and any shock and the generation of hunting is prevented.

Suspension control apparatus

In a suspension control system for a suspension supporting a mass body on a support base via a parallel combination of a spring means variable damp coefficient, absolute displacement (Z) and absolute having a variable spring coefficient and a shock absorber having a velocity (Z) of the mass body along a moving path of expansion and contraction of the spring means and the shock absorber, and relative displacement (Y) and relative velocity (Y) of the mass body in reference to the support base along the moving path are respectively obtained, and the damp coefficient of the shock absorber is controlled according to the ratio of the absolute velocity to the relative velocity (Z/Y) so as to be substantially proportional thereto, while the spring coefficient of the spring means is controlled according to the ratio of the absolute displacement to the relative displacement (Z/Y) so as to be substantially proportional thereto.

Suspension control system with variable damp and spring coefficients

A suspension control system for a suspension supporting a mass body on a support base via a parallel combination of a shock absorber having a variable damping coefficient and a spring. The control system cyclically measures absolute velocity (Z) of the mass body along a moving path of expansion and contraction of the shock absorber, relative velocity (Y) of the mass body in reference to the support base along the moving path, and acceleration (Z) of the mass body along the moving path. A control unit of the control system controls the damping coefficient according to a ratio (Z/Y) of the absolute velocity to the relative velocity with cyclic readjustment thereof so that at least either the damping coefficient is greater relative to the ratio when the acceleration is rich in low frequency components or a frequency of the cyclic readjustment of the damping coefficient is lower when the acceleration is rich in high frequency components.

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Toyota, Japan

Kazuo Ogawa