VISVESVARAYA TECHNOLOGICAL UNIVERSITY
A Seminar Report on
"GAS SHOCK ABSORBER"
Submitted in the partial fulfilment of requirement for the award of
BACHELOR OF ENGINEERING
SHASHIKUMAR REDDY M R (1BY12ME409)
For the academic year (2014-15)
Under the Guidance of
Dr K.M. SATHISH KUMAR
Department of Mechanical Engineering
BMS INSTITUTE OF TECHNOLOGY& MANAGEMENT
(Affiliated to Visvesvaraya Technological University)
Doddaballapura Main road,
Avalahalli, Yelahanka, Bangalore-560064
The shock absorber is an integral part of the
car's safety, and having shock absorbers in good
condition is just as important as having good
brakes, tyres and active safety systems.
Gas shock absorbers represent an advance
over traditional shock absorbers. At high speeds,
the flow of oil in the cylinder can cause foam of oil
and air to form. This limits the optimum through
put of the flow in the valves. The addition of
nitrogen gas under pressure into shock absorbers ,
this results increases efficiency.
Single tube with high pressure
Twin-tube with low pressure
Gas shock absorbers operate on the same basic
principle of movement of the piston in an oil
filled tube but they contain, at one end, a small
quantity of nitrogen under high pressure (25
The floating piston is prevented from mixing of
the oil with the gas .
Due to the constant pressure in the single tube
gas shock absorber , this constant pressure
eliminates cavitation and foaming which could
degrade the effectiveness of the shock absorber.
In the twin- tube shock absorber, at top of the
reserve tube, nitrogen under relatively low-
pressure. This low pressure is to improve the
efficiency of the shock absorber.
Some basic principles need to be respected
when installing shock absorber:
Consult the main catalogue.
Tighten the mounting
Check and adjust
Incorrect spring action may produce a fork
angle that is too steep or too flat. This in turn will
give a tendency for over steering or under
steering, which could seriously affect the
handling characteristics of the motorcycle.
Better fade resistance
No need for re-adjustment
At high speed, when shock occurs there will be
mixing of fluid and air and also continuous use of
the fluid increases the temperature will reduces
damping effect. Hence by using gas shock
absorber we can overcome from these problems
and increases efficiency.