A suspension control apparatus includes a variable damping coefficient type shock absorber disposed between sprung mass and unsprung mass of a vehicle and an actuator for setting and adjusting a damping coefficient of the variable damping coefficient type shock absorber on the basis of a control signal. An upward and downward absolute velocity detector for detecting an upward absolute velocity and a downward absolute velocity of the vehicle is provided. A control unit changes a signal from the upward and downward absolute velocity detector in accordance with a running condition of the vehicle to obtain a control target signal. A control signal generator outputs the control signal for the actuator on the basis of the control target signal from the control unit. A signal representative of the roughness of a road surface on which the vehicle is running is generated and a feature of the control unit is adjusted for changing the control signal on the basis of the signal representative of the road surface roughness.

Suspension control apparatus

A vehicle height adjust control apparatus includes a plurality of actuators provided between a vehicle body and a plurality of wheels that are capable of changing a vehicle height at a wheel position corresponding to each of a plurality of wheels of the vehicle, a vehicle height detector that detects an actual vehicle height at different positions, a controller for controlling the actuators to eliminate deviations of each of the actual vehicle heights detected by the vehicle height detector from corresponding predetermined target vehicle heights and a simultaneous controller linked with the controller that simultaneously changes the actual vehicle height at individual wheel positions by controlling the actuators if the actual vehicle heights detected by the vehicle height detector are deviated from the corresponding target vehicle heights by at least a predetermined value toward the same side.

Vehicle height adjust control apparatus and method

The technical field of the invention generally concerns electronically controlled valves for use in electro-hydraulically controlled transmissions. The valve 20 includes a hollow cage 42 pierced by tank ports 52, clutch ports 54, and by pump ports 56. The pump ports 56 receive fluid from a pump. The clutch ports 54 supply fluid to a hydraulic actuator. The cage clutch ports 54 supply fluid at a pressure that is proportional to an electrical control signal applied to a coil 252 of the valve 20. The tank ports 52 return fluid from the valve 20 to a tank. Located in the cage 42 is a main spool 112 that moves laterally relative to the cage 42 for controlling a flow of hydraulic fluid between the clutch ports 54 and either the pump ports 56 or the tank ports 52. An electro-magnetically operated pilot valve regulates a control pressure of fluid applied to a control pressure surface 138 at one end of the main spool 112. A feedback pressure passage 126, having a feedback restriction orifice 128, couples the pressure of fluid in the clutch ports 54 to a feedback pressure surface 114 at the opposite end of the spool 112. The orifice 128 restrains the rate at which fluid flows between the clutch ports 54 and the feedback pressure surface 114. One embodiment of the valve 20 includes a pressure spike suppression check valve 504 for relieving any abnormally high pressure that occurs in the clutch ports 54.

Proportional pressure control valve

In a system for controlling active suspensions of a motor vehicle, having fluid suspensions for the respective wheels, a lateral acceleration sensor, control valves for the respective suspensions, and a controller for adjusting the control valves to charge and discharge a fluid into and out of the fluid suspensions so as to control the vehicle attitude, a shut-off valve is provided between each control valve and each fluid suspension. The shut-off valve is normally open to enable the control of the vehicle attitude in an active state. When the detected lateral acceleration of the vehicle during a turn exceeds a set reference lateral acceleration, an active-passive changeover circuit delivers a shut-off signal to each shut-off valve thereby to close the shut-off valve, whereby all the fluid suspensions are sealed so that the suspension system becomes a passive state. This enables the elimination of the excessive peformance of the active suspension system and makes the suspension units smaller and less costly, reducing energy consumption.

System for controlling active suspensions of a vehicle

A vehicle hydraulic suspension system has front left (15), front right (16), rear left (18) and rear right (17) wheel ram. There is a mode decoupling device (100) with first (129), second (130), third (132) and fourth (131) balance chambers formed by a cylinder/piston rod assembly (124,125,126). The compression chamber (45) of the front left wheel ram (15) is in fluid communication with the first balance chamber (129), the compression chamber (46) of the front right wheel ram (16) is in fluid communication with the second balance chamber (130), the compression chamber (48) of the rear left wheel ram (18) is in fluid communication with the third balance chamber (132), and the compression chamber (47) of the rear right wheel ram (17) is in fluid communication with the fourth balance chamber (131). There are also front and rear resilient vehicle support means between vehicle body and the wheel assemblies.

Hydraulic system for a vehicle suspension

A pressure control system for suspension delivers a pressure which is proportional to a current level chosen to energize a solenoid of a pressure control valve to a shock absorber of a suspension. A change in the pressure of a return path which supplies a low pressure to the pressure control valve causes the pressure which is applied to the suspension to change. In order to suppress such change, a junction of the pressure control valve with the return path has an orifice interposed therein or is connected to a low pressure accumulator. On the other hand, in the event a depression occurs in the output of the high pressure piping, a cut valve which functions to isolate the suspension from the pressure control valve may be temporarily cut off in response to a pressure fluctuation in the high pressure piping. In order to prevent this, an orifice is interposed between the high pressure piping and a pilot chamber of the cut valve.

Pressure control system for suspension

In a hydraulic suspension system, a plurality of actuators having working fluid chambers are provided. Each actuator is adapted to increase and decrease vehicle height as the results of the supply and the discharge of working fluid to and from its working fluid chamber, respectively. Working fluid supply passages supply working fluid at supply pressure to the working fluid chambers and working fluid discharge passages discharge working fluid from the working fluid chambers. Cut-off valves and pressure control devices are provided in the supply passages and the discharge passages. Each cut-off valve is adapted to remain in its closed position whenever the supply pressure is not more than a predetermined value. Each pressure control device is adapted to control the supply of the working fluid to and the discharge from the associated working fluid chamber to adjust the pressure within the chamber. The system further comprises devices for detecting the pressures within the working fluid chambers and a device for determining the supply pressure. The pressure control devices are controlled so that their controlling pressures may substantially be equal to the pressures within the associated working fluid chambers determined by the pressure determining devices at least until the cut-off valves are opened.

Hydraulic suspension system for a vehicle with less abrupt change in vehicle height when started

In a fluid pressure type active suspension in a vehicle such as an automobile in which a fluid pressure type actuator supporting a vehicle body from a wheel so as to be able to vary a vehicle height of the vehicle body relative to the wheel in accordance with a fluid pressure supplied in its fluid chamber is operated by a pressure control means which controls the fluid pressure supplied in the fluid chamber of the actuator according to certain control parameters including at least a rate of change of the vehicle height or an acceleration of the vehicle body, the control means is adapted to modify an actual value of the rate of change of the vehicle height or the acceleration of the vehicle body for use in the control of the fluid pressure to be less than the actual value thereof when the rate of change of the vehicle height or the acceleration of the vehicle body is greater than a threshold value therefor.

Fluid pressure type active suspension responsive to change of rate of change of vehicle height or change of acceleration of vehicle body

In a fluid pressure type active suspension in a vehicle such as an automobile, having a fluid pressure type actuator supporting a vehicle body from a wheel so as to be able to vary a height of the vehicle body relative to the wheel in accordance with a fluid pressure supplied to its fluid chamber, a fluid supply passage for supplying a working fluid to the fluid chamber of the actuator, a fluid exhaust passage for exhausting the working fluid from the fluid chamber of the actuator, and a pressure control circuit including a switching-over valve traversing the fluid supply passage and the fluid exhaust passage so as to be operated by a pilot pressure to selectively connect the fluid chamber of the actuator with either the fluid supply passage or the fluid exhaust passage for controlling the fluid pressure supplied to the fluid chamber of the actuator, a variable throttle valve for generating the pilot pressure for operating the switching-over valve from the pressure of the working fluid in the fluid supply passage by releasing a part of the working fluid therefrom, and a throttle control device for controlling the variable throttle valve so as to control the pilot pressure to a target value, the pressure control circuit comprises a means for modifying the target value to be lowered when the difference between the pressure of fluid in the fluid supply passage means at an upstream side of the pressure control circuit and the target value is smaller than a certain threshold value.

Kouichi Kokubo

Papers

Pressure control system for suspension

Hydraulic suspension system for a vehicle with less abrupt change in vehicle height when started

Fluid pressure type active suspension responsive to change of rate of change of vehicle height or change of acceleration of vehicle body

Fluid pressure type active suspension with bypass control for working fluid pressure operative with variable target value