Nissan Motor Company Limited

Yosuke Akatsu

Naoto Fukushima

Masaharu Sato

Kensuke Fukuyama

Itaru Fujimura

Takeshi Kimura

Yukio Fukunaga

Kazuo Ikawa

Sunao Hano

Namio Irie

Yasuji Shibahata

Hideo Tobata

An apparatus for estimating vibration input to be transferred from a road surface to a suspension device of a vehicle. The apparatus converts stroke displacement values (S.sub.FL, S.sub.FR) detected by stroke sensor (27FL, 27FR) arranged on locations near the front wheels into stroke speed values (S.sub.VFL, S.sub.VFR) by differentiating circuits (41a, 41b) including a high-pass filer whose cutoff frequency (f.sub.HC) is set at substantially twice the spring-bottom resonance frequency (20 Hz, for example). The apparatus further converts body work vertical acceleration values (Z.sub.GFL, Z.sub.GFR) detected by vertical acceleration sensors (28FL, 28FR) arranged on locations near the front wheels into spring-top speed values (Z.sub.VFL, Z.sub.VFR) by integrating circuits (41c, 41d) including a low-pass filter whose cutoff frequency (f.sub.LC) is set at nearly one sixth of the spring-top resonance frequency (0.2 Hz, for example). The apparatus adds these speed values to each other by adders (41e, 41f) to provide differential values (x.sub.OFL ', x.sub.OFR ' ) of the spring-bottom displacement values obtained by accurately estimating the vibration input from a road surface by cancelling the spring-top speeds with each other.

Apparatus for estimating vibration input to a suspension device

An actively controlled suspension system for automotive vehicles includes a lateral acceleration sensor and a controller for suppressing rolling of the vehicle. The controller controls a distribution ratio of anti-roll moment or lateral load shift between a driven wheel and a non-driven wheel so as to enhance steering characteristics of the vehicle. The controller changes the distribution ratio depending on both the lateral acceleration and the wheel speed difference between the driven wheel speed and the non-driven wheel speed such that the distribution ratio at a non-driven wheel side of suspension system is increased from a designated reference value according to the increase in the wheel speed difference and a rate of change in the distribution ratio is attenuated towards the designated reference value according to the increase in the lateral acceleration.

Actively controlled suspension system for automotive vehicles

An automotive suspension control system for anti-rolling motion control is provided. This system serves to adjust wheel loads acting on driven wheels when a wheel speed difference between the driven wheels is greater than a preselected value, concluding that slippage occurs at one of the driven wheels, the adjustment is carried out for securing traction of a slipping driven wheel. The system is responsive to lateral acceleration acting on a vehicle body to decrease a degree of adjustment of the wheel loads according to increase in the lateral acceleration for enhancing cornering stability on road surfaces having different friction coefficients.

Automotive active suspension system for anti-rolling control

An active suspension system for an automotive vehicle is arranged to regulate the attitude of a vehicle body in a flat or balanced state by controlling hydraulic cylinders respectively disposed between a vehicle body and a road wheel, in response to an attitude change of the vehicle body. The active suspension system comprises electromagnetically operated variable vibration attenuation valves, each of which is fluidly connected with each hydraulic cylinder and is followed by an accumulator. Each variable vibration attenuation valve is adapted to be variable in its attenuation constant in response to a vertical acceleration experienced by the road wheel. The variable vibration attenuation valve takes on a low attenuation constant to maintain a high riding quality of the vehicle under a normal cruising condition, and a high attenuation constant to suppress the response of the road wheel under a rough road cruising condition.

Active suspension system

A hydraulic cylinder assembly to be used in an actively controlled suspension system includes a built-in pressure accumulator. The pressure accumulator employed in the hydraulic cylinder assembly has a reciprocally movable free piston for dividing a fluid chamber and a pneumatic chamber. The free piston thrustingly moves for establishing pressure balance between the fluid chamber and the pneumatic chamber and, in turn, for establishing pressure balance between the fluid chamber and an associated pressure chamber in the hydraulic cylinder so as to accumulate pressure while the fluid in the associated pressure chamber is compressed and to supply the pressure when the associated pressure chamber expands while absorbing vibration energy exerted between a vehicle body and a suspension member.

Hydraulic cylinder assembly for automotive suspension system and

The pressure outputs of a power steering control valve are fed either to hydraulic cylinders (or servos) or to chambered elastomeric insulator units to, in the case of the rear wheels, produce a bias which opposes a side force produced during cornering to prevent the rear wheels from undergoing 'compliance steering', while in the case of front wheels, induce same to turn through an angle slightly greater than intended by the driver to either prevent compliance steering or increase same to improve vehicle handling when cornering respectively .

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Yokohama, Japan

Yosuke Akatsu