Hydro pneumatic suspension system
Use of additional electronic sensors and driver
control of suspension performance
Softer springs – better damping of road forces and
superior driver comfort
But it also leads to collapse under given weight in
case of heavy vehicles.
Balancing of Both Handling & Comfort.
When The Vehicle goes into potholes or bump, the
Suspension geometry changes.
On loading ground clearance decreases.
Unequal braking effort generated.
Resonance frequency vary as per the changing
stiffness of the suspension system.
While cornering, vehicle rolls about its longitudinal
Cant keep the tyre contact with ground at all time.
Loss of traction on bump and dips.
Vehicle becomes dynamic unstable at high speed.
To overcome problems of conventional
Better load distribution per axle
Decreases overload problem
Increases ride comfort
1] A standard Citroën sphere
2] A hydraulically controlled isolation valve
3] A ball and piston valve
4] Two damping elements
5 ]An electrically controlled valve
1. uses an inert gas, nitrogen (colored
blue) as spring medium
Principle- Exactly the opposite of Boyle’s Law!
2. The flexibility of gas decreases as
What does Boyle’s Law Say?
increasing load compresses
By keeping the mass of the gas constant and changing the volume
of its container, its pressure can be controlled.
3. Leading to reduction in volume of gas
and adding to its pressure
For a pneumatic system- Air/gas is admitted or withdrawn from
the system by compressors and exhaust valves, modifying its mass 4. Damping effect is obtained by forcing
while keeping the volume constant.
fluid through two way restrictor
between cylinder and piston
ADVANCEMENT IN SUSPENSION
Conventional Spring System
THIRD GENERATION- HYDROACTIVE 3
HYDROACTIVE 3 +
• guarantees a constant ride height regardless of
the load or number of passengers
1.Fluid pump independent of engine and
• lowering the car at speeds above 110 kmh to
optimize stability and fuel economy.
2. Computer supervises the car body height
• On rough roads, it automatically raises for
increased clearance and comfort.
• The Hydractive III+ suspension system is
maintenance free for 5yrs/200,000kms.
• Similar to hydractive 2.
NEXT GENERATION- HYDROACTIVE 4
Hydractive 4 will offer
1. Dynamic Leveling
2. Each wheel will have separate height
corrector & Pair of sphere.
3. Each wheel be able to independently switch
between a firm and soft setting.
Body roll is kept to an absolute minimum
leading dynamic leveling, preventing pitch , yaw
Ground clearance can be kept constant under any load
Suspension geometry of the vehicle remains same in
Because of this system, it keep the vehicle in contact with
the road at all time.
The failure of sensor can cause uneven vehicle
Major Precaution should be taken while changing
Costly compared to conventional suspension
No need of Anti-Roll bar in vehicle.
Hydractive suspension system is maintenance free till 5
Increases the dynamic stability of vehicle by lowering the
ride height when the vehicle speed increases above 110
Well packaged system leading to optimum space utilisation
Hydractive Suspension is the need of todays automobile.
Handling & comfort can be achieved in todays need.