HydroPneumatic suspension systems have several main advantages over other suspension types: - They are well-suited for heavy load applications over 12 tons and provide independent leveling control and load stabilization. - They allow for a more stable suspension force and spring rate compared to other suspension types, as well as better control over suspension frequency. - HydroPneumatic suspensions are necessary when level control is needed frequently, such as for adjusting to major load changes, or when a manual operator control of suspension level is desired. They are robust for harsh working environments.

1. Why
HydroPneumatic
Suspension?
Author: Eng. Leandro O. Santos
linkedIN: leandro-oliveira-santos-82974813/

2. Why HydroPneumatic Suspension?
Main Advantages
▪ For heavy load applications
▪ >12 ton axles
▪ Big Load Ratio
▪ Load and unload vehicles
▪ Independent leveling control
▪ Great roll stabilization

3. Suspension types Comparison
 For more stable Suspension Force and Spring Rate

4. Natural Frequency of the suspensions
 From 1 to 100 Hz they are sensed to be accelerations and displacements, in the frequency range of 20 Hz–10 kHz
they are perceived acoustically (noise).
 Reimpell points out that the range from 1 to 4 Hz determines the subjective estimation of the “suspension
comfort” while the range from 4 to 80 Hz influences what is called “harshness” [REI05] – low amplitude and short term
accelerations resulting for example from rides over cobblestone paving.
 ISO2631-1 indicates that excitations in the frequency range from 0.1 to 0.5 Hz are responsible for motion sickness.
Better control for Suspension Frenquency

5. Comparison & Advantages

6. When Hydropneumatic Suspensions are
necessary?
 (a) a level control is needed in particular for level readjustments after major load changes,
 (b) a level control needs to work frequently and needs to react quickly,
 (c) a manual operator control for the suspension level is desired,
 (d) little space is available for suspension elements,
 (e) possibly hydraulic cylinders are already available for control of the desired suspension degree of freedom,
 (f) robust components are required due to the harsh working environment,
 (g) a lockout of the suspension in the design position is required,
 (h) the spring rate needs to be adjustable,
 (i) a hydraulic energy supply is already available.
Points a, b, f and i are the reasons why hydro-
pneumatic suspension systems can be found in all
kinds of off-road vehicles