Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Masanaga Suzumura

Tadao Tanaka

Minoru Tatemoto

Mitsuhiko Harara

Naotake Kumagai

Yasutaka Taniguchi

Hiroki Abe

Sunao Chikamori

Shozo Takizawa

Shinichi Takeuchi

Kazuyoshi Kobayashi

Tasutaka Taniguchi

Wheel suspension units each having fluid spring chambers are arranged in a vehicle suspension apparatus. A roll control quantity determined in accordance with the relationship between a vehicle velocity and a steering angular velocity, i.e., inlet solenoid valves and exhaust solenoid valves, are controlled in accordance with a solenoid ON/OFF time, thereby controlling the roll of a vehicle.

Vehicle suspension apparatus

A microcomputer performs roll control and communication control. In roll control, when the steering state detecting means and vehicle velocity detecting means detect a factor which causes a roll state of the vehicle body, a second control signal is produced to open desired supply and exhaust control valve so as to supply a preset amount of fluid to the fluid spring chambers of contracted suspension units and to exhaust a preset amount of fluid from the fluid spring chambers of stretched suspension units. In communication control, a first control signal is supplied to the communicating means to open the communication control valve when the steering state sensor detects that the steering angle falls within a preset steering angle and to close the communication control valve otherwise. After generation of the first control signal, when the steering state sensor detects that the steering direction of the steering wheel is in a return direction toward the neutral position and the steering angular velocity is lower than a preset steering angular velocity, a third control signal is supplied to the communicating means so as to open the communication control valve. When the steering state sensor detects, a third preset time after a second preset time from the generation of the third control signal, that the steering angle has reached the preset neutral range, a fourth control signal is produced to close the communication control valve for a fourth preset time.

In a vehicle suspension apparatus having air spring chambers between the vehicle body and the respective wheels to perform height and position control modes by controlling supply control valve means for supplying air to the air spring chambers and exhaust control valve means for exhausting air from the air spring chambers, the vehicle suspension apparatus has a high-pressure reserve tank connected to the respective chambers through the supply control valves, a first compressor for supplying compressed air to the high-pressure reserve tank, a low-pressure reserve tank connected to the respective chambers through the corresponding exhaust control valves and the suction port of the first compressor, and a second compressor for supplying atmospheric air to the high-pressure reserve tank through a check valve and a drier arranged between the check valve and the second compressor. In the position control mode, the compressed air is exhausted from the chambers to the low-pressure reserve tank through the exhaust control valves. In the height control mode, the compressed air is slowly exhausted from the corresponding chambers through the exhaust control valve means via the drier, thereby regenerating the drier during height down control.

In a vehicle suspension apparatus, front and rear wheel suspension units respectively have air spring chambers. Air is supplied to predetermined air spring chambers from an air source through a supply control valve, and at the same time air is exhausted from remaining air spring chambers through an exhaust control valve. Three-directional valves are inserted between the respective air spring chambers and the exhaust control valve. One end of a front wheel communication path is connected to the front left wheel three-directional valve and the other end of the path is connected to the front right wheel three-directional valve. Similarly, one end of a rear wheel communication path is connected to the rear left wheel three-directional valve and the other end of the path is connected to the rear right wheel three-directional valve. The air passing through the supply control valve is supplied to the front wheel air spring chambers through the front wheel communication path or to the rear wheel air spring chambers through the rear wheel communication path. Each of the three-directional valves can take the first position where the air spring chambers communicate with the supply control valve or the second position where the air spring chambers communicate with the exhaust control valve, thereby decreasing the numbers of valves and paths so as to perform position control.

In a vehicle suspension apparatus comprising communication control means for producing a disabling control signal for disabling the communicating solenoid valves when conditions are satisfied that the velocity detected by the velocity sensor exceeds a preset velocity and the steering angle detected by the steering sensor exceeds a preset steering angle and for producing an enabling control signal when the conditions are not satisfied, and roll control means for producing a control command signal for opening desired ones of the supply and exhaust control valves for a preset control time in order to supply a preset amount of fluid to contracted fluid spring chambers along a roll direction and for exhausting a preset amount of fluid from stretched fluid spring chambers when the conditions are satisfied, the preset velocity as one of the conditions determined by the communication control means is set to have a first value when the communicating solenoid valves are enabled and to have a second value larger than the first value when the communicating solenoid valves are disabled. With this apparatus, passengers experience uniform centrifugal force sensations when roll control is started and cancelled. Discomfort experienced by passengers during and after roll control is reduced to a minimum.

A vehicle suspension apparatus has air spring chamber provided at a suspension unit for supporting a rear wheel, air supply means for supplying air to the air spring chamber of the suspension unit for supporting the rear wheel through supply opening and closing valve, air exhaust means for exhausting air from the air spring means of the suspension unit for supporting the rear wheel, a parking brake sensor for detecting the operated state of a parking brake, and a shift position detecting sensor for detecting the shift position of an automatic transmission having a fluid drive unit for transmitting drive power to wheels. The parking brake sensor detects whether or not the parking brake is engaged. The shift position detecting sensor detects whether or not the shift position of the automatic transmission is operated from any of parking position (P) and neutral position (N) to running position (D, L, 2) to raise the vehicle height of the rear wheel side to supply air to the air spring chamber of the rear wheel side. The fact that the shifting position of the automatic transmission is operated from either the parking position (P) or the neutral position (N) to the running position (R) is detected to exhaust air from the air spring chamber of the rear wheel side to lower the vehicle height of the rear wheel.

A vehicle suspension apparatus including suspension units each provided for each wheel and having an air spring chamber is disclosed, in which rolling control and vehicle height control are done through control of air to and from the air spring chambers. The driving of a reservoir tank for storing compressed air to be supplied to the air spring chambers, is inhibited until the engine operation has been stabilized after the start of the engine preset level. In this way, the problems in the engine lubrication and idling are solved, and the defficiencies of the starting property of the engine are overcome.

The characteristic of the suspension is held to be a soft one when the vehicle is running along a flat surface, while it is automatically switched by the switch unit to a hard one when the cycle period T of vertical vibration of the vehicle height becomes near the cycle of the natural vibration of sprung mass of the suspension at the time of running along a road having an irregular surface or jumping a projection, thereby suppressing the resonance of the vehicle body due to external force applied from the road to improve the comfortability.

A suspension apparatus has suspension units which have individual fluid spring chambers and are arranged on the wheels. When a detected negative acceleration (deceleration) exceeds a reference negative deceleration, front wheel fluid supply valves are opened for a control time T to supply a predetermined amount of fluid to the front wheel spring chambers and rear wheel fluid extent valves are opened for the control time T to exhaust a predetermined amount of fluid from the rear wheel fluid spring chambers, thereby decreasing nose dive at the time of deceleration.

A suspension apparatus has suspension units mounted on wheels and each unit has a fluid spring chamber. Fluid is supplied to contracted fluid spring chambers and is exhausted from elongated fluid spring chambers to control the change in position of the vehicle. In the position control mode, a large-diameter path is selected to supply or exhaust a large amount of compressed fluid. In the height control mode, a small-diameter path is selected to supply or exhaust a small amount of compressed fluid. The required amounts of compressed fluid can be supplied to the fluid spring chambers in both the position and height control modes.

Wheel suspension units each having fluid spring chambers are arranged in a vehicle suspension apparatus. A roll control quantity, determined in accordance with the relationship between a vehicle velocity and a steering angle, i.e., inlet solenoid valves and exhaust solenoid valves are controlled in accordance with solenoid ON/OFF time, thereby controlling rolling of the vehicle.

Air spring chambers are provided in suspension units of respective wheels, and air intake solenoid valves and exhaust solenoid valves are provided corresponding to the air spring chambers. Further, switching means for switching the suspension units between the hard and soft states is provided, and when the vehicle's velocity, detected by the vehicle velocity sensors, is less than the set velocity, the suspension units are set to the soft state, and when the vehicle's velocity is the set velocity or higher, the suspension units are set to the hard state to control the switching means in a vehicle suspension apparatus.

A vehicle suspension apparatus including suspension units each provided for each wheel and having an air spring chamber is disclosed. When steering wheel is quickly returned toward the center position at the time of a slalom running, it is detected from the steering angular velocity and vehicle velocity that the vehicle body has begun to be returned to a neutral state, and communication control valves are opened before the reaching of the center position, i.e., before the steering angle reaches an insensitive range. Rolling control thus can be improved without delay in the restoration of the position of the vehicle body even at the time of a high speed slalom running, at which time the steering wheel is repeatedly operated quickly.

The front wheel exhaust valves and the rear wheel supply valves are opened for a predetermined period of time when rapid acceleration of the vehicle is detected by the accelerator pedal sensor and the gear position sensor, the absolute value of change in vehicle position and its velocity can be properly controlled. Therefore, comfort and steering stability can be improved as compared with vehicles mounting of the conventional apparatus. In addition, since an acceleration state is detected by the gear position sensor as well as the accelerator pedal sensor, rapid acceleration of the vehicle can be accurately detected, thereby preventing unnecessary position control.

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Nagoya, Japan

Masanaga Suzumura