Modern Mechanical Engineering, 2011, 1, 84-92
doi:10.4236/mme.2011.12011 Published Online November 2011 (http://www.SciRP.org/journal/mme)
Copyright © 2011 SciRes. MME
Design, Development and Testing of an Air Damper to
Control the Resonant Response of a SDOF Quarter-Car
Suspension System
Ranjit G. Todkar
Department of Mechanical Engineering, P.V.P. Institute of Technology, Sangli, India
E-mail: rgtodkar@gmail.com
Received October 21, 2011; revised November 3, 2011; accepted November 10, 2011
Abstract
An air damper possesses the advantages that there are no long term changes in the damping properties, there
is no dependence on working temperature and additionally, it has less manufacturing and maintenance costs.
As such, an air damper has been designed and developed based on the Maxwell type model concept in the
approach of Nishihara and Asami and Nishihara [1]. The cylinder-piston and air-tank type damper character-
istics such as air damping ratio and air spring rate have been studied by changing the length and diameter of
the capillary pipe between the air cylinder and the air tank, operating air pressure and the air tank volume. A
SDOF quarter-car vehicle suspension system using the developed air enclosed cylinder-piston and air-tank
type damper has been analyzed for its motion transmissibility characteristics. Optimal values of the air
damping ratio at various values of air spring rate have been determined for minimum motion transmissibility
of the sprung mass. An experimental setup has been developed for SDOF quarter-car suspension system
model using the developed air enclosed cylinder-piston and air-tank type damper to determine the motion
transmissibility characteristics of the sprung mass. An attendant air pressure control system has been de-
signed to vary air damping in the developed air damper. The results of the theoretical analysis have been
compared with the experimental analysis.
Keywords: Ride Comfort, Quarter-Car Suspension Model, Cylinder-Piston and Air-Tank Type Air Damper,
Motion Transmissibility, Optimal Air Damping Ratio
1. Introduction
The control of response of the sprung mass of a SDOF
quarter-car suspension system subjected to the road ex-
citation is necessary in the neighborhood of the reso-
nance for the better ride comfort, road holding and sta-
bility. Various damping mechanisms such as, hydraulic,
electromagnetic, ER and MR fluid and air dampers have
been reported in the literature [1-3]. In this paper, an air
enclosed cylinder-piston and air-tank type air damper con-
figuration has been selected for design and development
because in these dampers there are no long term changes
in the damping properties, no dependence on working
temperature. Air dampers have less manufacturing and
maintenance costs. A SDOF quarter-car vehicle suspen-
sion model using such a developed air damper has been
analyzed for its motion transmissibility characteristics.
The air damper has been designed and developed as a
Maxwell type model in the approach of Nishihara and
Asami and Nishihara [1]. The air damper characteristics
such as air damping ratio and air spring rate have been
studied. Optimal values of the air damping ratio at vari-
ous values of air spring rate have been determined to ob-
tain minimum motion transmissibility of the sprung mass.
An experimental setup for SDOF quarter-car suspension
system using the developed air enclosed cylinder-piston
and air-tank type damper has been developed with an
attendant air pressure control system.
2. Development of an Air Enclosed
Cylinder-Piston and Air-Tank Type
Damper
A cylinder-piston and air-tank type damper, both the sides
of which are connected to two surge tanks through capil-
lary pipes has been developed. The arrangement is used