22-08-2014, 11:27 AM
Production of Compressed Air Using Vehicle Suspension System Project Report
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Introduction
The project is related to a production of compressed air using vehicle or says
automobile suspension system. Compressed air is air kept under a pressure that is
greater than atmospheric pressure. Compressed air has been used from earlier years for
power mine locomotives, and was previously the basis of naval torpedo propulsion. In
1863, Jules Verne wrote a novel about a world of glass skyscrapers, high-speed trains,
and air-powered automobiles. Recently several companies have started to develop
Compressed air cars although none have been released to the public or have been
tested by third parties. It serves many domestic and industrial purposes. In Europe, 10
percent of all industrial electricity consumption is to produce compressed air
amounting to 80 terawatt hour consumption per year. The advantages of compressed
air are well publicized since the developers need to make their machines attractive to
investors. Compressed-air vehicles are comparable in many ways to electric vehicles,
but use compressed air to store the energy instead of batteries. The principle
advantages for an air powered vehicle are their potential advantages over other
vehicles include, Compressed air technology reduces the cost of vehicle production by
about 20%, because there is no need to build a cooling system, fuel tank, spark plugs
or silencers. Air, on its own, is non-flammable. The mechanical design of the engine is
simple and robust. Low manufacture and maintenance cost as well as easy
maintenance. Compressed-air bottles can be disposed of or recycled with less pollution
than batteries. Compressed air vehicles are unconstrained by the degradation problems
associated with current battery systems
Positive displacement type compressor
Positive-displacement air compressors work by forcing air into a chamber whose
volume is reduced to compress the air. Piston-type air compressors use this principle
by pumping air into an air chamber through the use of the constant motion of pistons.
They use one-way valves to guide air into a chamber, where the air is
compressed. Rotary screw compressors also use positive-displacement compression by
matching two helical screws that, when turned, guide air into a chamber, whose
volume is reduced as the screws turn. Vane compressors use a slotted rotor with varied
blade placement to guide air into a chamber and compress the volume
Rotary Screw Compressors:
Rotary air compressors are positive displacement compressors. The most common
rotary air compressor is the single stage helical or spiral lobe oil flooded screw air
compressor. These compressors consist of two rotors within a casing where the rotors
compress the air internally. There are no valves. These units are basically oil cooled
(with air cooled or water cooled oil coolers) where the oil seals the internal clearances.
Since the cooling takes place right inside the compressor, the working parts never
experience extreme operating temperatures. The rotary compressor, therefore, is a
continuous duty, air cooled or water cooled compressor package
Centrifugal Compressors
The centrifugal air compressor is a dynamic compressor which depends on transfer of
energy from a rotating impeller to the air.
Centrifugal compressors produce high-pressure discharge by converting angular
momentum imparted by the rotating impeller (dynamic displacement). In order to do
this efficiently, centrifugal compressors rotate at higher speeds than the other types of
compressors. These types of compressors are also designed for higher capacity
because flow through the compressor is continuous.
Adjusting the inlet guide vanes is the most common method to control capacity of a
centrifugal compressor. By closing the guide vanes, volumetric flows and capacity are
reduced.
The centrifugal air compressor is an oil free compressor by design. The oil lubricated
running gear is separated from the air by shaft seals and atmospheric vents. [2
Suspension System
The suspension system of an automobile is one which separates the wheel assembly
from the body. The primary function of the suspension system is to isolate the vehicle
from shocks and vibration due to irregularities of the road surface. The suspension
system of an automobile includes springs, shock absorbers and their mountings. These
relatively heavy assemblies constitute what is known as ―Sprung‖ weight. ―Unsprung‖
weight, on the other hand, includes wheels and tire, break assemblies and other
structural members not supported by the springs.
The modern automobile has come along way since the day when ―just being self
propelled‖ was enough to satisfy the car owner. Improvement in suspension, increased
strength & durability of components, and advances in tire design and construction has
made large contributions to tiding comfort and driving safety. Basically, suspension
refers to the use of front and rear springs to suspend a vehicles frame, body, engine &
power train above the wheels. The springs used in today's cars and trucks are
engineered in a wide variety of types, shapes, sizes, rates and capacities. Types include
leaf springs, coil springs, air springs and torsion bars. These are used in sets of four
per vehicle, or they are paired off in various combinations and are attached to the
vehicle by a number of different mounting techniques. [3]
Types of Suspension
There are mainly three types of suspension system conventional system, Air system
and hydraulic system. In conventional system mainly the leaf spring, coil spring and
torsion bars are use. There are two types of front suspension in general use: the
independent system & the solid axle system. Independent suspension usually operates
through heavy-duty coil springs or torsion bars and direct, doubles acting shock
absorbers. In solid axle construction, the axle beam and wheel assemblies are
connected to the car by leaf springs and direct or in-direct shock absorber
Leaf Spring:
Front leaf springs are used in conjunction with solid axle beams in most truck
applications. Rear leaf springs are used on trucks and some passenger cars. Single leaf
or multi-leaf springs are usually mounted longitudinally over the front axle beam or
under the rear axle housing. For many years, Ford used leaf springs at rear, coil
springs in front. Now, full-size cars have coil spring suspension, front and rear. Ford’s
small cars have coil springs in front; leaf springs at rear. In some foreign cars, torsion
bars are used front and rear; in others, leaf springs are mounted crosswise for use with
independently suspended wheels. Rear leaf spring in U.S vehicles generally are placed
parallel to the frame to absorb the torque of the driving wheels the front half of each
leaf spring acts like a radius rod or control arm to transmit the driving force from the
rear wheels to the frame. With this suspension setup, the leaf springs also serve as
stabilizer side way of the chassi
Torsion Bars
Although torsion bars were and are used extensively on European cars, this type of
suspension system received only token attention from the U.S. manufacturers until
Chrysler developed their system in the early 1950s. Before that only a few buses,
trailers and race cars were equipped with torsion bar suspension. Basically, torsion bar
suspension is a method of utilizing the flexibility of a steel bar or tube twisting
lengthwise to provide spring action. Instead of the flexing action of a leaf spring, the
torsion bar twists to exert resistance against up and down movement. For example, an
independently suspended front system with torsion bars mounted lengthwise would
have one end of the bars anchored to the car frame and the other end attached to the
lower control arms. With each rise and fall of a front wheel, the control arm pivots up
and down, twisting the torsion bar along its length to absorb road chock and cushion
the ride.
Air Suspension
In the Air suspension system are designed to cushion the ride and keep the car, bus or
truck level fore and aft and at a constant height regardless of load. Air suspension was
introduced on many luxury cars in the late 1950s, but it was dropped after one or two
model years. Recently, however, new leveling systems have been researched and
developed for passenger car use, including air—adjustable rear shock absorber. A
typical air suspension system consists of an engine-driven air compressor, supply tank,
filter or condenser, valves, piping, controls and air springs or bellows. In operation, the
air compressor maintains a constant pressure in the supply tank. Air is piped to the
control valves, which feed air to each spring as needed. Pressure is automatically
increased on either side or at front or rear as required to keep the car level and to keep
any desired height from the road (within limit of system). [3]
Literature Review
This research project explored the feasibility of enhancing suppression crews of
limited manpower by equipping them with Class A foam and Compressed Air Foam
Systems (CAFS) technology and training. The problem that was addressed was that,
especially in the early stages of fire suppression operations, there were frequently
insufficient personnel to employ traditional extinguishment methods safely and
efficiently. The purpose of this research project was to determine if CAFS technology
and procedures could be used to increase effectiveness, efficiency, and safety under
limited personnel resource conditions. Descriptive research, including the literature
review, was used to explore the safety and operational results of understaffing, and to
clarify the present state of development of compressed air foam and Class A foam.
Evaluative research was used to measure hose line handling for CAFS and traditional
(plain water) hand lines. [5]
Agricultural vehicle manufacturers are employ
Component
Non Return Valve
This valve is used to speed up the piston movement and also it acts as a one – way
restriction valve which means that the air can pass through only one way and it can’t
return back. By using this valve the time consumption is reduced because of the faster
movement of the piston
Safety Valve
The principle type of device used to prevent overpressure in plant is the safety or
safety relief valve. The safety valve operates by releasing a volume of fluid from
within the plant when a predetermined maximum pressure is reached, thereby reducing
the excess pressure in a safe manner. As the safety valve may be the only remaining
device to prevent catastrophic failure under overpressure conditions, it is important
that any such device is capable of operating at all times and under all possible
conditions.
Safety valves should be installed wherever the maximum allowable working pressure
(MAWP) of a system or pressure-containing vessel is likely to be exceeded. In steam
systems, safety valves are typically used for boiler overpressure protection and other
applications such as downstream of pressure reducing controls. Although their primary
role is for safety, safety valves are also used in process operations to prevent product
damage due to excess pressure. Pressure excess can be generated in a number of
different situations, including:
Design
Reciprocating compressor
In industry, reciprocating compressors are the most widely used type for both air and
refrigerant compression as shown in the fig. They work on the principles of a bicycle
pump and are characterized by a flow output that remains nearly constant over a range
of discharge pressures. Also, the compressor capacity is directly proportional to the
speed. The output, however, is a pulsating one.
Design of Piston
Material used for piston is cast iron.
Let,
P = Maximum air pressure in N/mm2
,
D = Diameter of piston in mm,
?t = Permissible tensile stress in MPa,
tH = Thickness of piston head in mm,
H = Heat flowing through the piston head in kJ/s or watts,
K = Heat conducted in W/m/0C
TC = Temperature at the center of piston head in 0C
TE = Temperature at the edge of piston head in 0C
Working of Compressed Air Production Using Vehicle Suspension
The pushing power is converted into compressed air energy by proper driving
arrangement. The Pneumatic single acting cylinder is used for this project. The spring
arrangement is fixed at the outside of the pneumatic cylinder. The output air from the
pneumatic cylinder is collected in air tank through non-return valve. The stored
compressed air in the air tank is allowed to flow through flow control valve for use in
the various applications. Here spring is used to take the piston at its position by tension
of spring
Conclusion
By this project we conclude that we can produce compressed air without any power
input or fuel and vehicle produce compressed air itself by simple arrangement of
suspension system due to irregularity of road surface. This arrangement is
maintenance free. And this compressed air used in various application by suitable
arrangement.
By producing compressed air using vehicle or say automobile suspension system we
can improve the efficiency of the engine by improving the air-fuel ratio of the engine.
Designing an air storage tank for 150 psi is applicable to various automobile
applications like air brake system, wiper application. Designing this type of
mechanism in automobile vehicle we can improve the driving comfortless and also we
can improve the safety of the vehicle