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

axis.

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 suspension system

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

Principle- Exactly the opposite of Boyle’s Law! What does Boyle’s Law Say? By keeping the mass of the gas constant and changing the volume of its container, its pressure can be controlled.

For a pneumatic system- Air/gas is admitted or withdrawn from the system by compressors and exhaust valves, modifying its mass while keeping the volume constant.

1. uses an inert gas, nitrogen (colored blue) as spring medium

2. The flexibility of gas decreases as increasing load compresses suspension pistons

3. Leading to reduction in volume of gas and adding to its pressure

4. Damping effect is obtained by forcing fluid through two way restrictor between cylinder and piston

ADVANCEMENT IN SUSPENSION

HYDRACTIVE 1

HYDRACTIVE 2

HYDRACTIVE 3

Coming soon….

HYDRACTIVE 4

Conventional Spring System

Hydro pneumatic

Hydractive

FIRST GENERATION- HYDROACTIVE 1

SECOND GENERATION- HYDROACTIVE 2

THIRD GENERATION- HYDROACTIVE 3 HYDROACTIVE 3 +

Features 1.Fluid pump independent of engine and

electric

2. Computer supervises the car body height selection

• guarantees a constant ride height regardless of the load or number of passengers

• lowering the car at speeds above 110 kmh to

optimize stability and fuel economy.

• 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. ADVANTAGE Body roll is kept to an absolute minimum leading dynamic leveling, preventing pitch , yaw & roll.

ADVANTAGES Ground clearance can be kept constant under any load

variation.

Suspension geometry of the vehicle remains same in dynamic condition.

Because of this system, it keep the vehicle in contact with the road at all time.

No need of Anti-Roll bar in vehicle.

Hydractive suspension system is maintenance free till 5 years.

Increases the dynamic stability of vehicle by lowering the ride height when the vehicle speed increases above 110 km/hr.

Well packaged system leading to optimum space utilisation

The failure of sensor can cause uneven vehicle dynamics

Major Precaution should be taken while changing the tyres.

Costly compared to conventional suspension system.

Hydractive Suspension is the need of todays automobile.

Handling & comfort can be achieved in todays need.

Citroen Technical Guide.

http://en.wikipedia.org/wiki/Hydropneumatic_suspension http://www.carbibles.com/suspension_bible_pg3.html

http://www.citroencarclub.org.uk/drupal/node/36

http://www.citroenet.org.uk/miscellaneous/hydraulics/hydraulics-16.html

http://www.citroen.com.au/citroen-universe/technology/comfort/hydractive-iii-plus-suspension

http://www.autozine.org/technical_school/suspension/tech_suspension3.htm

http://citroen.tramontana.co.hu/suspension/various-suspension-systems http://www.myweb.com.au/citroen/cit_tech_hydropneu.htm