Hydropneumatic Suspension: Components and Operation
Item 7: Hydropneumatic Suspension
The hydropneumatic suspension system utilizes two fluids, a liquid and a gas, instead of conventional springs.
Principle of Operation
The system operates based on a hydraulic principle, using a cylinder-piston set as both a pressure generator and receptor.
Suspension Block
This replaces the spring-damper set in conventional systems. It includes:
- Cylinder: Attached to the vehicle body, with a sphere at one end.
- Sphere: Acts as the main accumulator, containing nitrogen gas.
- Piston: Moves within the cylinder, connected to the suspension arm.
- Shock Absorber: Uses deformable valves to control fluid flow.
Vehicle Layout
- Two Cylinders: One per wheel, connected to suspension links.
- Two Spheres: Function as pneumatic springs.
- Two Shock Absorbers: Reduce oscillations from road irregularities.
- Height Corrector: Maintains constant or adjustable vehicle height.
- Anti-Sink Valve: Prevents height loss when parked.
- Hydraulic Fluid: Mineral or synthetic, specific to hydraulic circuits.
High-Pressure Sources
These supply fluid pressure to the system:
- Storage Tank
- High-Pressure Pump
- Control Valves (Conjuntor-Breaker)
- Main Accumulator
- Safety Valve
High-Pressure Pump
Mechanically driven, it draws fluid from the tank and pressurizes it.
Conjuntor-Breaker
Regulates pressure between 145 and 170 bars.
Main Accumulator
Stores pressurized fluid for system needs.
Safety Valve
Ensures pressure for critical systems, like brakes, in case of failure.
Suspension System Components
- Cylinder: Allows wheel movement and height adjustment.
- Sphere: Contains nitrogen, acting as a pneumatic spring.
- Damper: Reduces oscillations.
- Height Corrector: Self-leveling valve to maintain height.
- Anti-Sink Valve
- Height Command
Rear Shock Absorber
Minimizes oscillations from uneven pavement.
Height Corrector
Adjusts fluid volume in the cylinders to maintain height.
Pneumatic Suspension
Uses a pneumatic spring between the frame and wheel axle. A compressed air source is required, often shared with air brakes.
Compressed Air Supply Circuit
Includes a compressor, wet deposit (to remove moisture), and auxiliary tanks for storing pressurized air.
High-Level Control
Maintains platform level regardless of load.