H YDROGAS S USPENSION S YSTEM FOR AFV - Amol Ugalmugale

I NTRODUCTION - AFV-Armored Fighting Vehicle Tracked Vehicle Hydro gas Suspension- Gas is used to act as a spring medium instead of material torsional spring. HGS is combination of three basic sub systems viz. hydraulic, gaseous and mechanical kinematics Hydrogas is the evolution of Hydroelastic

T RACKED VEHICLE

M AIN B ATTLE T ANK (MBT)

H ISTORY Great War- fixed suspensions—with no movement whatsoever. This was improved with leaf spring suspensions the Christie suspension was developed, which allowed the use of coil springs the Second World War the other common type was torsion-bar suspension Hydrogas suspension system is Invented by famous British automotive engineer Alex Moulton.

OBJECTIVES OF AFV SUSPENSIONS The tire force should be limited. The suspension workspace is restricted to stop large deflection of suspension. Axle vibrations are reduced. The suspension should be adaptable to ensure uniform performance under varying load conditions.

N EED OF HGS- To protect the sensitive board equipment. To provide stable platform for armanent. For correct steering. Due to problem with previous system like lubrication, varient target. Previous system could sustain low load.

C ONSTRUCTON - HGS consist of-: Stationary casing, A rotating crank A connecting rod and Sliding pistons inside the cylinders. Actuator cylinder and accumulator cylinder. The casing, crank, piston rod and the cylinder form a four-bar single slider crank mechanism to convert the rotary movement of the axle arm to linear piston displacement to compress the gas medium.

C ONSTRUCTION AND W ORKING OF HGS -

WORKING OF HGS- The track drags up the vehicle. The suspension road wheels rotate. When the vehicle comes in contact with an obstacle. The road wheel along with the axle arm swings up. The kinematic arrangement results in the displacement of the filled in hydraulic oil. This fluid compresses the accumulator piston against the entrapped nitrogen gas. Raising the pressure of the gas to offer sufficient load. After crossing the obstacle, the compressed gas expands and the pressure reduces so that the increased load is reduced to the static load.

A DVANTAGES -: Non linear spring rate. Provides more stable Gun platform. Offer smoother ride quality. Loss of weight due to replacement of conventional steel spring. Replacement of a suspension sphere is much easier and safer than replacing a conventional spring.

D ISADVANTAGES -: Service sometimes requires a specifically trained mechanic. expensive to repair or replace Failure will cause a drop in ride height and braking power will decrease.

A PPLICATIONS -: In automobiles. In Tracked Fighting vehicle. In tracked vehicle used in agriculture etc.

C ARS USING HYDRO GAS SUSPENSION - Austin Ambassador Princess Austin Allegro Austin Maxi(from March 1978 onwards) Austin Metro

A USTIN A MBASSADOR

P RINCESS

T RACKED AFV-

R EFERENCES -: Development of Hydro Gas Suspension for AFV: A Co-Simulation Approach Semi-active hydro-gas suspension system for a tracked vehicle Optimisation of Kinematics for Tracked Vehicle Hydro Gas Suspension System. Hydro-gas suspension system for a tracked vehicle: Modeling and analysis

T HANK YOU !