Understanding Hydropneumatic and Hydraulic Suspension Systems
Hydropneumatic Suspension
This system provides great flexibility and regulates body height independently of the vehicle load.
Advantages:
- Offers comfort
- Maintains correct body height
- Regulates the lower center of gravity
- Improves suspension in a vacuum
- Allows height adjustment of the body
- Provides better safety in case of a puncture
- Reduced maintenance
Hydraulic Suspension
This system transmits and ensures fluid motion as the union of mobile elements within pipelines. Gas replaces mechanical spring suspension, providing necessary elasticity.
1. Main Hydraulic Circuit
Consists of elements like the tank, pump, accumulator, main pressure regulator, safety valve circuit.
2. Hydraulic Suspension Components:
- Suspension blocks
- Height corrector
- Damper
- Cylinder
- Anti-drop valve
Components Explained:
- Deposit: A container storing hydraulic fluid, supplying the pump and allowing return after use.
- Source of Pressure: A high-pressure mechanical pump with constant flow.
- Pressure Regulator: Also called a set breaker, it’s a main circuit element ensuring regulated working pressure. Disjunction Phase: Pressure exceeds 170 bar, internal pressure overcomes spring pressure, closing alimentation. Conjunction Phase: Chambers reach 145 bar, changing the slider position.
- Accumulator: A reservoir of pressurized hydraulic fluid, providing fluid when the circuit demands it.
- Safety Valve: Gives preference to organs feeding safety-related vehicle components.
- 2-Sphere Suspension: Similar to the main accumulator, fulfilling the spring’s mission.
- Damper: Double-acting, inserted into the sphere’s lower floor.
- Cylinder: Transmits wheel movements through the suspension arm to the hydraulic fluid.
- Height Corrector: Maintains constant ride height regardless of the load.
- Anti-Drop Valve: A 5-way, 2-position valve functioning like a 4-way valve.
Height Regulation
- Automatic: Achieved through height correction using a flexible rod and stabilizer bar.
- Manual: Done by acting on the manual selector, transmitting movement to the valve axis.
Hydractive Suspension
This system varies suspension flexibility and damping, avoiding traditional dynamic balancing issues.
Suspension Operation States:
- Soft State: Stiffness controller allows hydraulic fluid circulation between suspension elements on the same axle, resulting in high flexibility, smooth cushioning, and soft anti-roll.
- Steady State: Regulatory rigidity prevents fluid movement between elements on the same axle, leading to low flexibility, firm cushioning, and firm anti-roll.
3. Hydraulic Components:
- Solenoid Regulator: Electro trigger allowing stiffness regulation based on UCE information.
- Regulatory Rigidity: Modifies suspension’s physical state according to solenoid excitation.
4. Electrical Components:
- Control Unit (CACULO): Manages input signals from sensors (pressure, speed, etc.) and commands the solenoid for parallel stiffness adjustment.
- Sport Control Switch: Allows the driver to choose between automatic and sport modes.
- Shutter Speed: A hall effect sensor providing an electrical signal proportional to the secondary tree’s speed.
- Steering Wheel Sensor: A double electro-optical sensor with two light emitters, two receivers, and a phonic wheel with windows, responsible for address.
- Bodywork Displacement Sensor: Defines suspension movement and average bodywork height, operating similarly to the steering wheel sensor.
- Accelerator Pedal Travel Gear: A variable resistance driven by the accelerator pedal, varying input voltage.
- Brake Pressure Sensor: A switch informing the ECU of brake pressure exceeding a preset value.
- Door and Trunk Switch: Switches connecting to the control unit, balancing feeding circuit pressures when a door opens or closes.
Maintenance and Self-Diagnosis of Hydractive Suspension
Breakdowns in the suspension system are stored in non-volatile memory.
Hydractive Suspension Evolution
Features electronically controlled height regulation and cash rigidity laws.