Sistemi Sospensioni S.p.a.

Marelli Suspension Systems Italy S.p.a.

Walter Bruno

Giordano Greco

Piero Antonio Conti

Fabio Cotto

Simone Marchetti

Marco Di Vittorio

Gianfranco De Lillo

Andrea Tonoli

Nicola Amati

Renato Galluzzi

Massimo Seminara

Massimo Trinchera

Matteo Vergani

Sanjarbek Ruzimov

Michele Spina

Pasquale Gatta

A method for controlling the damping characteristic of a shock absorber of a vehicle, particularly for compensating the variation of the operating temperature of the shock absorber, in an active or semi-active suspension system. The compensation of the variation of the operating temperature of the shock absorber takes place by: estimating a mechanical power dissipated in heat by the shock absorber; estimating a thermal power exchanged by the shock absorber with the environment; evaluating the current operating temperature of the shock absorber as a function of the dissipated mechanical power and of the thermal power exchanged with the environment; and controlling the driving current of the control valve of the shock absorber according to a shock absorber reference model indicating a relationship between the damping force of the shock absorber, the operating temperature of the shock absorber and the driving current of the control valve.

Compensation of the thermal effect in a vehicle suspension system

A method for estimating damping characteristics of shock absorbers in an active or semi-active suspension involves providing a reference model of a nominal relation between a road severity index related to vertical acceleration values, and the mean driving current of the control valves of the shock absorbers, acquiring respective relative acceleration or speed data of at least the front wheels of the vehicle with respect to the vehicle body, determining a value of the road severity index starting from relative acceleration or speed data of the front wheels of the vehicle with respect to the vehicle body, acquiring values representative of the mean driving current of the control valve of each shock absorber, comparing acquired value of the mean driving current with an expected value of the nominal mean driving current determined as a function of the road severity index according to the reference model, and determining a degradation condition if the acquired value does not correspond to the expected value.

Recognition of degraded performance in a vehicle suspension system

A damper and spring unit includes a damper having a cylinder and a rod extending along a first axis (z), a spring plate arranged around the cylinder and slidable with respect to the cylinder along the first axis (z), a spring resting at its bottom on the spring plate, and an electro-mechanical adjustment device interposed between the cylinder and the spring plate for adjusting in a continuous and controlled manner the vertical position of the bottom end of the spring and the height of the vehicle from the ground. The adjustment device includes an electric motor generating a rotary motion and a motion conversion mechanism having one screw extending along a second axis (z') parallel to the first axis (z), but spaced therefrom, and driven into rotation by the electric motor about the second axis (z&#x2032;), and a nut meshing with the screw and drivingly connected for translation with the spring plate.

Damper and spring unit for a vehicle suspension provided with an electro-mechanical adjustment device for adjusting the vertical position of the spring

A hydraulic shock-absorber comprises an outer cylindrical tube, an inner cylindrical tube defining with the outer cylindrical tube an annular chamber, a main piston slidably mounted in the inner cylindrical tube and dividing the inner volume of the inner cylindrical tube into an extension chamber and a compression chamber, both containing an incompressible damping fluid, a valve assembly mounted on a bottom wall of the inner cylindrical tube and comprising a first compression valve and a first intake valve, a cup-shaped body mounted in the inner cylindrical tube, inside the compression chamber, and an auxiliary piston rigidly connected to the main piston and configured to slide in the cup-shaped body at least during a final section of the compression phase of the shock-absorber. The shock-absorber further comprises a second compression valve configured as a non-return valve allowing the flow of the damping fluid only in the direction from a working chamber of the cup-shaped body towards a lower portion of the compression chamber.

Hydraulic shock-absorber, particularly for a vehicle suspension, with two compression valves

The actuator comprises a cylinder and a rod. The cylinder comprises an inner cylindrical tube and an outer cylindrical tube which extend coaxially to each other along a longitudinal axis (z). The inner cylindrical tube accommodates a plunger which is rigidly connected to the rod and separates an inner volume of the inner cylindrical tube into a compression chamber and an extension chamber, wherein at least the compression chamber contains oil. The inner cylindrical tube and the outer cylindrical tube enclose with each other a reservoir chamber which is permanently in fluid communication with the extension chamber via at least one first passage provided in the inner cylindrical tube and contains a pressurized gas in a first portion thereof and oil in a remaining portion thereof. The cylinder further comprises an intermediate cylindrical tube which extends along the longitudinal axis (z) between the inner cylindrical tube and the outer cylindrical tube and encloses, along with the inner cylindrical tube, an intermediate chamber permanently in fluid communication with the compression chamber via at least one second passage provided in the inner cylindrical tube. The actuator further comprises a check valve associated to the inner cylindrical tube to allow the oil to flow in the direction from the reservoir chamber to the compression chamber only, and an electrically-operated flow control valve which is associated to the intermediate cylindrical tube for controlling the flow of the oil between the intermediate chamber and the reservoir chamber. The flow control valve is movable between a first operating position, in which it allows the oil to flow between the intermediate chamber and the reservoir chamber, and a second operating position, in which it prevents the oil from flowing between the intermediate chamber and the reservoir chamber.

Hydraulic linear actuator with a locking system for locking the compression movement of the actuator

The hydraulic shock-absorber comprises a hydraulic stop member having a cup-shaped body, which is adapted to be mounted in a compression chamber, and a plunger, mounted at an end of a rod of the shock-absorber so as to slide in the cup-shaped body when the shock-absorber moves towards the compression end-of-travel position. The cup-shaped body comprises a side wall and a bottom wall which define, along with the plunger, a working chamber in which a damping fluid of the shock-absorber is compressed by the plunger when the latter slides in the working chamber towards the bottom wall of the body. Axial channels are formed on the inner surface of the side wall of the body and allow the damping fluid to flow axially out of the working chamber when the plunger slides in the working chamber towards the bottom wall of the cup-shaped body. The axial channels extend parallel to a longitudinal axis (z) of the cup-shaped body and have a cross-section whose area decreases continuously along this axis (z) towards the bottom wall of the cup-shaped body.

Hydraulic shock-absorber for a vehicle suspension

The hydraulic stop member comprises: a cup-shaped body mounted in a compression chamber of the shock-absorber. A piston is mounted at an end of a rod of the shock-absorber so as to slide in the cup-shaped body when the shock-absorber is close to an end-of-travel position of the compression stroke. The cup-shaped body includes a side wall and a bottom wall which define, along with the piston, a working chamber where a damping fluid of the shock-absorber is compressed by the piston. A bypass conduit connects a working chamber with the portion of the compression chamber placed above a seal ring. A pressure relief valve keeps the bypass conduit closed as long as the pressure in the working chamber remains below a given threshold value and to open the bypass conduit, thereby allowing the discharge of the damping fluid from the working chamber to the compression chamber through the bypass conduit, when the pressure in the working chamber exceeds the threshold value.

Hydraulic compression stop member for a hydraulic shock-absorber for a vehicle suspension with pressure relief device

A piston () comprises a first pair of passive flow-control valves () [namely, a first compensation valve () and a first rebound valve ()], a second pair of passive flow-control valves () [namely, a second compensation valve () and a second rebound valve ()], and a flow-dividing solenoid valve () shiftable between a first operating position [in which it allows flow of a damping fluid between an upper chamber and a lower chamber of a shock absorber through the first pair of passive flow-control valves () and second pair of passive flow-control valves ()] and a second operating position [in which it allows the flow of the damping fluid between the upper chamber and lower chamber through only the second pair of passive flow-control valves ()]. The solenoid valve () is normally open (i.e., it is normally kept in the first operating position).

Piston for a damping-adjustable shock-absorber, particularly for a vehicle suspension, provided with four passive flow-control valves and with a flow-dividing solenoid valve

A flow-control passive valve controls flow of fluid between an upstream space at high pressure and downstream space at low pressure. The valve comprises a valve body in fluid communication with the upstream and downstream spaces and within which are defined first and second spaces. A movable member is slidably received in a body chamber, and a force is applied to the member tending to keep it in a given 'non-working' position. Metering discs meter the flow from the upstream to downstream space through the body and comprise first, second, and third fixed restrictors and first and second variable restrictors. Pressure in the first space is lower than that in the upstream space via a pressure drop through the first fixed restrictor while pressure in the second space is variable between the pressure in the first space and that in the downstream space depending on the position of the member.

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Asti, Italy

Walter Bruno