Compressed air vehicle report

Compressed Air Vehicle
Department of Mechanical Engineering, MMCT, Mangalore Page 1
CHAPTER 1
INTRODUCTION
Fossil fuels (i.e., petroleum, diesel, natural gas and coal) which meet most of the world's
energy demand today are being depleted rapidly. Also, their combustion products are
causing global problems, such as the green house effect, ozone layer depletion acid rains
and pollution which are posing great danger for environment and eventually for the total
life on planet. These factors are leading automobile manufactures to develop cars fueled
by alternatives energies. Hybrid cars, Fuel cell powered cars, Hydrogen fueled cars will
be soon in the market as a result of it. One possible alternative is the air powered car. Air,
which is abundantly available and is free from pollution, can be compressed to higher
pressure at a very low cost, is one of the prime option since atmospheric pollution can be
permanently eradicated. Whereas so far all the attempts made to eliminate the pollution
has however to reduce it, but complete eradication is still rigorously pursued.
Compressed air utilization in the pneumatic application has been long proven. Air
motors, pneumatic actuators and
Others various such pneumatic equipments are in use. Compressed air was
also used in some of vehicle for boosting the initial torque. Turbo charging has become
one of the popular techniques to enhance power and improve the efficiencies of the
automotive engine that completely runs on compressed air. There are at two ongoing
projects (in France, by MDI and in S. Korea) that are developing a new type of car that
will run only on compressed air. Similar attempt has been made but to modify the
existing engine and to test on compressed air.
1.1 SCARCITY OF FOSSIL FUELS
Fossil fuels, as the name suggests, are very old. Although humans probably used fossil
fuels in ancient times, as far back as the Iron Age, it was the Industrial Revolution that
led to their wide-scale extraction. About 100 years ago, the major source of energy
shifted from recent solar to fossil fuel (hydrocarbons). Technology has generally led to a
greater use of hydrocarbon fuels, making civilization vulnerable to decreases in supply.
The current study made in the year 2004, predicts that if the oil is consumed at the current
rates, then by 2020, we will be consuming 80% of the entire available resource.

Latest studies and projections available indicate that the crises of fossil fuel in near future
are inevitable and alternative to fossil fuel must be looked for. Some of the studies made
in this regard are detailed ahead.
1. When the wells run dry, We use more oil than we find, and if producers are fixing their
figures the end could be closer than thought, by Adam Porter, "Predicting the end of the
age of oil can be a sticky business. The Association for the Study of Peak Oil and Gas
(Aspo), a collection of industry figures, politicians and academics, held its annual
meeting at the Gulbenkian Museum in Lisbon..."
2. Peaking of World Oil Production: Impacts, Mitigation, & Risk Management, by Robert
L. Hirsch, SAIC, Roger Bezdek, MISI, Robert Wendling, MISI for the National Energy
Technology Laboratory of the US Department of Energy [2005 February] "The peaking
of world oil production presents the U.S. and the world with an unprecedented risk
management problem. As peaking is approached, liquid fuel prices and price volatility
will increase dramatically, and, without timely mitigation, the economic, social, and
political costs will be unprecedented. Viable mitigation options exist on both the supply
and demand sides, but to have substantial impact, they must be initiated more than a
decade in advance of peaking."
3. Expert says Saudi oil may have peaked, by Adam Porter [2005 February 22] : "As oil
prices remain above $45 a barrel, a major market mover has cast a worrying future
prediction. Energy investment banker Matthew Simmons, of Simmons & Co
International, has been outspoken in his warnings about peak oil before. His new
statement is his strongest yet, 'we may have already passed peak oil."
4. U.S. Energy Policy: A Declaration of Interdependence, by David J. O'Reilly Chairman
and CEO, ChevronTexaco Corporation [2005 February 15] "Simply put, the era of easy
access to energy is over. In part, this is because we are experiencing the convergence of
geological difficulty with geopolitical instability... We are seeing the beginnings of a
bidding war for Mideast supplies between East and West."
5. New Oil Projects Cannot Meet World Needs This Decade, by Oil Depletion Analysis
Centre [2004 November 16] "World oil supplies are all but certain to remain tight
through the rest of this decade, unless there is a precipitous drop in demand, according to
the results of a study by the London-based Oil Depletion Analysis Centre (ODAC). "The
study found that all of the major new oil-recovery projects scheduled to come on stream
over the next six years is unlikely to boost supplies enough to meet the world’s growing
needs."

1.2 INFLUENCE OF FOSSIL FUEL ON ENVIRONMENT
It is observed that with increasing pace of civilization, uses of transport have become
essential part of life and increasing in geometrical progression. This is leading to very
hazardous condition due to high rate of pollution. Many of the environmental problems
our generation faces today result from our fossil fuel dependence. These impacts include
global warming, air quality deterioration, oil spills, and acid rain.
Emissions from an individual car are generally low, relative to the smokestack image
many people associate with air pollution. But in numerous cities across the country, the
personal automobile is the single greatest polluter, as emissions from millions of vehicles
on the road add up. Driving a private car is probably a typical citizen’s most “polluting”
daily activity. Gasoline and diesel fuels are mixtures of hydrocarbons, compounds which
contain hydrogen and carbon atoms. In a “perfect” engine, oxygen in the air would
convert all the hydrogen in the fuel to water and all the carbon in the fuel to carbon
dioxide. Nitrogen in the air would remain unaffected. In reality, the combustion process
cannot be “perfect,” and automotive engines emit several types of pollutions like CO,
NOx, SO2, Volatile Organic Compounds,O3 etc.
1.3 INFLUENCE OF FOSSIL FUEL ON ECONOMY
Oil, the master energy resource, is the driver of economic growth. But our financial
system is wired for economic growth. This is the challenge. It is structural change that is
needed. Over the last 150 years relatively cheap oil has enabled economic growth to
happen. It has transformed agricultural methods, enabled world population to grow, and
powered transport. So now, not only are we required to adapt to life with less oil, but the
very enabler of economic growth is becoming more and more unaffordable.
Our economy may well recover somewhat, but that recovery will lead to increased oil
use, which leads to increased prices, which will lead to another economic contraction.
And this cycle will repeat – with each subsequent recovery being weaker than the last. So
no amount of optimism or wishful thinking can bring back economic growth. Future
economic growth will be impeded by the depletion of critical, natural resources, the
increased costs of extraction and its associated negative environmental impacts, and ever
mounting debt. This is not a temporary phenomenon, it is the start of a long series of
cyclical recessions, and it signifies the end of growth. It is a great disruption to our
normal patterns.

1.4 SEARCH FOR AN ALTERNATIVE FUEL
Many research works are being carried out to find the alternative to fossil fuel.
Alternative fuels, known as non-conventional or advanced fuels, are any materials or
substances that can be used as fuels, other than conventional fuels. Conventional fuels
include: fossil fuels (petroleum (oil), coal, and natural gas). Some well-known alternative
fuels include biodiesel, bioalcohol (methanol, ethanol, butanol), chemically stored
electricity (batteries and fuel cells), hydrogen, non-fossil methane, non-fossil natural gas,
vegetable oil, propane, and other biomass sources. Compressed Air is one of the
important and freely available alternative fuels.
1.5 FOSSIL FUEL: CONTEXT TO INDIA
India is developing country. Still per capita income of average person is very low to meet
out the minimum requirement of person. Maximum population of country is still living in
villages. There transport is still either bi-cycle or Motor Bike. Current hike of fossil fuel
is going tremendously high up to 30-40 % every year. With this pace up to 2010 prices
may go double than what is today and by 2030-40, it may fetch to Rs.1000 per litre. A
time will come when common person would not be able to purchase fuel to even run the
Motor-Bike. It is not only due to rate of increase of vehicles in India. It is worldwide
problem that 80 % of fossil fuel is being consumed in transport with increasing mobility
of persons today and daily consumable materials are being transported through Road
Transport. Thus it is need of day to explore possibility of alternative for fossil fuel to
make environment free from emission & make children healthy. With high rate of
consumption of fossil fuel it also necessary to make sustainable energy or in other words
of our Hon. President of India Dr. APJ Abdul Kalam make INDIA energy freedom by
2030, which he has spoken in his speech on the eve of 14th Aug.’2005 of Independence
day. So we need a focus on Alternative Fuel Research.

CHAPTER 2
HISTORY OF COMPRESSED AIR ENGINE
One cannot accurately claim that compressed air as energy and
locomotion vector is recent technology. At the end of the 19th century, the first
approximations to what could one day become a compressed air driven vehicle already
existed, with the arrival of the first pneumatic locomotives. In fact, two centuries before
that Dennis Papin apparently came up with the idea of using compressed air (Royal
Society London, 1687). In 1872 the Mekarski air engine was used for street transit,
consisting of a single stage engine. It represented an extremely important advance in
terms of pneumatic engines, due to its forward thinking use of thermodynamics, which
ensured that the air was heated, by passing it through tanks of boiling water, which also
increased its range between fill-ups. Numerous locomotives were manufactured and a
number of regular lines were opened up (the first in Nantes in 1879).
Figure 2.1 (a) Figure 2.1(b)
Figure 2.1(c)

In 1892, Robert Hardie introduced a new method of heating that at the same time served
to increase the range of the engine. However, the first urban transport locomotive was
not introduced until 1898, by Hoadley and Knight, and was based on the principle that
the longer the air is kept in the engine the more heat it absorbs and the greater its range.
As a result they introduced a two-stage engine.
Charles B. Hodges will always be remembered as the true father of the
compressed air concept applied to cars, being the first person, not only to invent a car
driven by a compressed air engine but also to have considerable commercial success with
it. The H.K. Porter Company of Pittsburgh sold hundreds of these vehicles to the mining
industry in the eastern United States, due to the safety that this method of propulsion
represented for the 2 mining sector. Later on, in 1912, the American’s method was
improved by Europeans, adding a further expansion stage to the engine - 3 stages.

CHAPTER 3
COMPRESSED AIR
3.1 COMPRESSED AIR
Compressed air is a gas, or a combination of gases, that has been put under greater
pressure than the air in the general environment. Numerous and diverse, including jack
hammers, tire pumps, air rifles, and aerosol cheese are some of the current applications
using compressed air. In this case Compressed air can also be defined as the fuel having
the potential as a clean, inexpensive, and infinitely renewable energy source. Its use is
currently being explored and can be an alternative to fossil fuels.
3.2 BEHAVIOR OF COMPRESSED AIR
Compressed air is clean, safe, simple and efficient. There are no dangerous exhaust fumes
of or other harmful by products when compressed air is used as a utility. It is a non-
combustible, non-polluting utility. When air at atmospheric pressure is mechanically
compressed by a compressor, the transformation of air at 1 bar (atmospheric pressure)
into air at higher pressure (up to 414 bar) is determined by the laws of thermodynamics.
They state that an increase in pressure equals a rise in heat and compressing air creates a
proportional increase in heat. Boyle's law explains that if a volume of a gas (air) halves
during compression, then the pressure is doubled. Charles' law states that the volume of a
gas changes in direct proportion to the temperature. These laws explain that pressure,
volume and temperature are proportional; change one variable and one or two of the
others will also change, according to this equation:
P1 V1
T1
=
P1 V1
T1
Compressed air is normally used in pressure ranges from 1 bar to 414 bar (14 to 6004
PSI) at various flow rates from as little as 0.1 m (3.5 CFM -cubic feet per minute) and up.
3.3 AVAILABILITY
Air is natural source and available freely in atmosphere, which can be stored after
compressing it to desired pressure. This is the only source which can be stored at very
high pressure and can be retained without any loss after lapse of passage of time, which
can drive so many domestic appliances such as vacuum cleaner, mixy and pumps,

running Power generator when electric power is off instead of using inverter to have
clumsy arrangements of battery etc.
3.4 COMPRESSED AIR ENGINE
This engine was developed between the end of 2001 and the beginning of 2002. It uses an
innovative system to control the movement of the 2nd generation pistons and one single
crankshaft. The pistons work in two stages-one motor stage and one intermediate stage of
compression/expansion. The engine has 4 two-stage pistons, i.e. 8 compression and/or
expansion chambers. They have two functions: to compress ambient air and refill the
storage tanks and to make successive expansions (reheating air with ambient thermal
energy) there by approaching isothermal expansion. Figure 3.4 shows the compressed air
engine.
Two technologies have been developed to meet different needs:
 Single energy compressed air engines; and
 Dual energy compressed air plus fuel engines.
Figure 3.4: Compressed air engines
The single energy engines will be available in both Minicat’s and Citycats. These
engines have been conceived for city use, where the maximum speed is 50 km/h and
where MDI believes polluting will soon be prohibited. The dual energy engine, on the
other hand, has been conceived as much for the city as the open road and will be
available in all MDI vehicles. The engines will work exclusively with compressed air
while it is running under 50 km/h in urban areas. But when the car is used outside urban

areas at speeds over 50 km/h, the engines will switch to fuel mode. The engine will be
able to use gasoline, gas oil, bio-diesel, gas, liquidized gas, ecological fuel, alcohol, etc.
Both engines will be available with 2, 4 and 6 cylinders, When the air tanks are empty the
driver will be able to switch to fuel mode, thanks to the car’s on board computer.

CHAPTER 4
WORKING AND PRINCIPLE
4.1 THE PRINCIPLE OF COMPRESSED AIR ENGINE
A typical single-cylinder CAE, as shown in Figure 4.1(a), is composed of an intake valve
(shown by number 1), an exhaust valve (indicated by number 2), a cylinder (indicated by
number 3), a piston (shown by number 4), a connecting rod (shown by number 5) and a
crankshaft (shown by number 6). In the suction power stroke, compressed air enters the
cylinder via the intake valve because of the pressure difference, drives the piston
downward. Then the intake valve closes when the crank reaches a certain angle. While
the compressed air continues to push the piston down and output mechanical work. The
schematic diagram of a CAE automobile system, as demonstrated in Figure 4.1(b), is
mainly consist of a CAE, an high pressure air tank, an buffer tank, two pressure sensors,
two regulators, an air operated pressure relief valve (TESCOM), an electronic
proportional directional control valve (FAIRCHILD), a silencer, a signal processor. The
airflow path starts from the high pressure air tank then through buffer tank, control valve
and eventually accesses the CAE. The airflow mass, entries into the CAE, is controlled
by the valve position. And the valve is managed by externally applied electric current,
denoted by i, when i equals to 4 mA, the valve will be fully closed, and fully open when i
is equal to 20 mA.
Figure 4.1(a): Single cylinder CAV engine

1. Intake valve
2. Exhaust valve
3. Cylinder
4. Piston
5. Connecting rod
6. Crankshaft.
THERMODYNAMIC PROCESS ANALYSIS
Figure 4.1(b): The ideal schematic diagram of CAE automobile
ELEMENTS FUNCTIONS
1. Pressure Sensor Calculate The Pressure Of Storage Tank
2. High Pressure Air Tank Store Up And Provide High Pressure Air
3. Regulator Regulate Gas Pressure
4. Buffer Tank Provide Appropriate Pressure Air To
CAE
5. Regulator
Regulate Gas Pressure
6. Electronic Proportional Directional
Control Valve
Modulate the amount of entering air
which controls the elements 7
7. Air Operated Regulator Modulate The Pressure Of Entering Air
And Control Of CAE
8. Pressure Sensor Calculate The Pressure Of Airflow
9. CAE Provide The Power
10. Silencer Reduce The Noise
11. Controller Measure pressure and output the analog
signal to the electronic control valve

For the CAE, the high pressure air at normal temperature could supply the driving force.
The reason of the shaft work is the impulse action and the dynamic action of the high
compressed air. Thermodynamically, the process is considered reverse to the course of
the piston-type air compressor. The ideal thermodynamic process can be shown as Figure
4.1(c), intake process and exhaust process are considered constant pressure process, and
expansion process is considered adiabatic process. The theoretical work is given as
follows.
W5-2 =P1 (V1-V2) (1)
W2-3=P1V1/ (1-k) [(V3-V2) ^ (1-k)-1] (2)
W3-5=P4 (V1-V3) (3)
Woutput=W5-2+W2-3+W3-5 (4)
where, Wouputt is the theoretical work done, P1 and V2 represent the supply pressure and
volume, respectively, at which the air push down the piston downward movement, V1 is
the clearance of cylinder, P3and V3 are the pressure and volume, respectively, up to
which the maximum expansion of air takes place, and P4 is the pressure at which the
piston discharges the air to the environment.
Figure 4.1(c): Ideal working cycle
4.2 WORKING OF COMPRESSED AIR ENGINE (CAE)
A compressed air engine is a type of engine which does mechanical work by expanding
compressed air. Pneumatic engine generally convert compressed air energy to mechanical

work either into linear motion or rotatory motion. Where linear motion is come from
diaphragm and rotary motion is come from either a vane type air motor or piston air
motor. Pneumatic motors which are existed in many forms from the past two centuries,
many compressed air engines improve their performance by modifying their compressed
air tank and heating the incoming air or the engine itself. The given Figure 4.2 (a) show
rotary engine and figure 4.2(b): show a newly design reciprocating engine that operated
by compressed air, here modification is done with tank where compressed air is stored.
Approximately 90 m3 of compressed air is stored in fiber tanks in the vehicle. The engine
is powered by compressed air, stored in a carbon-fiber tank at 30 MPa (4500 psi). The
tank is made of carbon fiber in order to reduce its weight. The engine has injection
similar to normal engines, but uses special crankshafts and pistons, which remain at top
dead centre for about 70 degrees of the crankshaft’s cycle; this allows more power to be
developed in the engine. The expansion of this air pushes the pistons and creates
movement. The atmospheric temperature is used to re-heat the engine and increase the
road coverage. The air conditioning system makes use of the expelled cold air. Due to the
absence of combustion and the fact there is no pollution, the oil change is only necessary
every 50,000 km.
Figure 4.(a): Rotary Compressed Air Engine with modified tank

Figure 4.2(b): 3D-Diagram of an Engine that operated by compressed air
The working mechanism of compressed air powered engine partially similar with
conventional 4-stroke engine. But, it has only two strokes like:
1. Power Stroke
2. Exhaust stroke
 Power Stroke
In power stroke of CAE, High pressurize air via inlet valve, supply to cylinder and
it will move the piston from TDC to BDC. Problem concerned to working of this
engine at starting, it requires initial torque to be provided by other means to bring
engine into motion. This can be solved by providing DC powered exciter motor
which provides necessary initial torque to be start.
 Exhaust Stroke
In exhaust stroke of CAE, air escape from cylinder via exhaust valve and inlet
valve get closed. One interesting benefit is that the exhaust air temperature of
C.A.E measured practically as low as 17.60C is less than atmospheric temperature.
Conventional four stroke engine is modified into two stroke engine with re-
designing of CAM.

4.3 COMPRESSED AIR TECHNOLOGY
The basic object with Compressed air Technology is to implement in vehicle for
consumption of minimum amount of energy and remain the output works same. In
today’s world, everyone wants to afford a vehicle and its energy to power it. Engine air
technology makes it happen from many aspects. It is very less in term of mass as
compared with other sources of energy for transportation of man or material. It also
improves urban life style through sustainability &Non-polluting vehicle. Its impact on the
environment is also concededly low. It remains with intelligence, lighter, style and
comfort. Most of the work done by an air compressor is during compression stroke. This
will add energy to the air by increasing its pressure. Compression also produces heat,
however, and the amount of work required to compress a quantity of air to a given
pressure depends on how fast this heat is removed. The compressed work done will lie
between the theoretical work requirements of two processes and they are:-
 ADIABATIC
A process which have no cooling and the heat does remains in the air which causing
pressure rise that increases compression work requirements for the maximum value.
 ISOTHERMAL
A process that provides perfect cooling, in which no changing in temperature of air
and the work required for compression is tends to the minimum.” But the given fig:
indicates that isothermal expansion is higher than adiabatic expansion, the volume of
the compressed air and flow rate are controlled at a particular compressed pressure.
Figure 4.3: Energy Released As a Function of Compressed Pressure at Constant
Volume

CHAPTER 5
COMPONENTS OF CAE
CONSTRUCTION OF COMPRESSED AIR ENGINE
The construction of compressed air engine is very easy and simple and can be constructed
at low cost as it mainly consist of pneumatic cylinder, pneumatic solenoid valve and
working, light chaser circuit, compressor, bearing & it’s working, crank shaft cam shaft
tank etc.
5.1 PNEUMATIC CYLINDER ENGINE
The mechanical devices such as Pneumatic cylinders (sometimes known as air cylinders)
use the power of compressed gas to produce a force in a reciprocating linear motion. Like
hydraulic cylinders, something forces a piston to move in the desired direction. The
piston is a disc or cylinder, and the piston rod transfers the force it develops to the object
to be moved. Engineers sometimes prefer to use pneumatics because they are quieter,
cleaner, and do not require large amounts of space for fluid storage. Because the
operating fluid is a gas, leakage from a pneumatic cylinder will not drip out and
contaminate the surroundings, making pneumatics more desirable where cleanliness is a
requirement.
5.2 COMPRESSOR
A Gas Compressor is a mechanical device whose work is to increase the pressure of a gas
by reducing its volume. An air compressor is specific type of gas compressor.
Compressors are similar to pumps: both the compressor and pump increase the pressure
on a fluid and both can transport the fluid through a pipe. As gases are compressible, the
compressor also reduces the volume of a gas. Liquids are relatively incompressible; while
some can be compressed, to pressurize and transport liquids is the main action of a pump.
Compressed air Piston range operates between 0.75 kW to 420 kW or in horse power is
1hp to 563hp producing working pressure at 1.5 bar to 414 bar or in PSI is 21 to 6004
PSI.

5.3 CRANK SHAFT
The crankshaft translates reciprocating linear piston motion into rotation. To convert the
reciprocating motion into rotation, the crankshaft has "crank throws" or "crankpins",
additional bearing surfaces whose axis is offset from that of the crank, to which the "big
ends" of the connecting rods from each cylinder attach.
5.4 CAM SHAFT
Figure 5.4(a) Modified CAM shaft Figure 5.5(b) cam profile
The cam shaft originally had two cams with one lobe each which were mutually
perpendicular to each other. The crank rotates due to the movement of the piston; the
camshaft is attached with the crankshaft by a timing chain or a timing belt. And as the
crank rotates the camshaft also rotates and hence the timing of the valves is managed. In
the traditional camshaft the inlet n exhaust valve both functions In the modified camshaft
the lobe of the cam working for the inlet valve was filed and cam was made circular, also
the cam working for the exhaust valve was provided with another lobe right opposite to
the lobe already present. This ensured the inlet valve to be closed and exhaust valve to
work with changed timing.
5.5 TANK
The tanks must be designed to safety standards appropriate for a pressure vessel, such as .
The storage tank may be made of:
1. Steel,
2. Aluminium,
3. Carbon Fiber
4. Kevlar,

5. Other materials or combinations of the above.
The fiber materials are considerably lighter than metals but generally more expensive.
Metal tanks can withstand a large number of pressure cycles, but must be checked for
corrosion periodically. One company stores air in tanks at 4,500 pounds per square inch
(about 30 MPa) and hold nearly 3,200 cubic feet (around 90 cubic metres) of air. The
tanks may be refilled at a service station equipped with heat exchangers, or in a few hours
at home or in parking lots, plugging the car into the electrical grid via an on-board
compressor.
Figure 5.5: Carbon Fiber tank
5.6 DISTRIBUTION AND VALVES
To ensure smooth running and to optimize energy efficiency, the engines use a simple
electromagnetic distribution system which controls the flow of air into the engine. This
system runs on very little energy and alters neither the valve phase nor its rise.
Figure 5.6: Distribution valve

5.7 THE AIR FILTER
The MDI engine works with both air taken from the atmosphere and air pre-
compressed in tanks. Air is compressed by the on-board compressor or at service stations
equipped with a high-pressure compressor. Before compression, the air must be filtered
to get rid of any impurities that could damage the engine. Carbon filters are used to
eliminate dirt, dust, humidity and other particles, which unfortunately, are found in the air
in our cities. This represents a true revolution in automobiles - it is the first time that a car
has produced minus pollution, i.e. it eliminates and reduces existing pollution rather than
emitting dirt and harmful gases. The exhaust pipe on the MDI cars produces clean air,
which is cold on exit (between -15º and 0º) and is harmless to human life. With this
system the air that comes out of the car is cleaner than the air that went in.
Figure 5.7: Air filter
5.8 THE CHASSIS
Based on its experience in aeronautics, MDI has put together highly resistant, yet light,
chassis, aluminium rods glued together. Using rods enables us to build a more shock-
resistant chassis than regular chasses. Additionally, the rods are glued in the same way as
aircraft, allowing quick assembly and a more secure join than with welding. This system
helps to reduce manufacture time.
Figure 5.8: Chassis of the CAV

5.9 THE BODY
The MDI car body is built with fibre and injected foam, as are most of the cars on
the market today. This technology has two main advantages: cost and weight. Nowadays
the use of sheet steel for car bodies is only because of cost - it is cheaper to serially
produce sheet steel bodies than fibre ones. However, fibre is safer (it doesn’t cut like
steel), is easier to repair (it is glued), doesn’t rust etc. MDI is currently looking into using
hemp fibre to replace fibre-glass, and natural varnishes, to produce 100% non-
contaminating bodywork.
Figure 5.9: Body of CAV
5.10 STEERING MECHANISM
The complete steering comprises of steering wheel, steering shaft, tie rods, universal
joint, ball type arrangement, rack and pinion arrangement, bellows for dust protection.
The steering wheel is connected to steering shaft which transfers the motion to rack and
pinion arrangement through universal joint. Tie rods provides motion to the wheel to
assist the turning. Hence, ultimately front wheels move in right and left direction.
5.11 GEAR BOX
Gear changes are automatic, powered by an electronic system developed by MDI. A
computer which controls the speed of the car is effectively continuously changing gears.
The latest of many previous versions, this gearbox achieves the objective of seamless
changes and minimal energy consumption.

5.12 BRAKE POWER RECOVERY
The MDI vehicles will be equipped with a range of modern systems. For example, one
mechanism stops the engine when the car is stationary (at traffic lights, junctions etc).
Another interesting feature is the pneumatic system which recovers about 13% of the
power used.

CHAPTER 6
SPECIFICATIONS
Power source
Electronically Injected compressed air
Compressed air: 300 bar
Recharge
Charger: On board 5.5 kwh 220 volt compressor
Recharge time: Less than 3 minutes at Compressed air station
Alternative Recharge Outlet: 220V electric outlet less than 4 hours
Oil change: 0.8 liters per 50,000 miles
Engine
cylinder: 500 c.c.
Power max. HP (kW): 25(18.3) at 3000 rpm
Torque max. Kgm (NM): 6.3(61.7) at 500-2500 rpm
Performance
Maximum speed: 60 mph
Range: 120 miles or 10 hours
Acceleration times: 0-30 mph in less than 3 seconds
Exterior and Body
Overall length: 151 in.
Overall width: 68 in.
Overall height: 69 in.
Weight: 1543 lbs.
Light weight provides Good road-holding due to low center of gravity and low
energy consumption.
Engine Mount: Rear
Suspension: Front coil springs, rear pneumatic
Steering mechanism: Rack and pinion
Body materials: Aluminum & fiberglass, Ensures good shock
absorption.
Compressed Air Tanks: Composite fiberglass
CHAPTER 7

FUELING PROCESS
7.1 FUELING METHODOLOGY
There are three modes of fuelling the air tank:
 Air Stations: Just as filling of petrol at petrol pump, air can be filled in tanks air
stations. They use a huge tank already filled with compressed air at high
pressure. This method is less time consuming air can be filled in 3-4 minutes.
 Domestic electric plug: This method uses compressor installed in homes. This is
a time taking process; it can consume up to 4 hours.
 Dual-energy mode: This method uses gasoline and compressed air both. The air
car will be provided with an onboard compressor. When the compressed air will
be finished the car will be using little amount of gasoline and use compressor to
fill the air tank. Using this method one can go upto 800 miles.
Figure 7.1: Charging method
CHAPTER 8

MODELS
8.1 FAMILY
A spacious car with seats which can face different directions. The vehicle´s design is
based on the needs of a typical family.
Figure 8.1
Characteristics: Airbag, air conditioning, 6 seats.
Dimensions: 3.84m, 1.72m, 1.75m
Weight: 750 kg
Maximum
speed:
110 km/h
Mileage: 200 - 300 km
Max load: 500 Kg
Recharge
time:
4 hours (Mains connector)
Recharge
time:
3 minutes (Air station)
8.2 VAN

Designed for daily use in industrial, urban or rural environments, whose primary drivers
would be tradesmen, farmers and delivery drivers.
Figure 8.2
Specifications: Airbag, air conditioning, ABS, 2 seats, 1.5 m3.
Weight: 750 kg
Maximum
speed:
110 km/h
Maximum
load:
500 Kg
Recharging
time:
Recharging
time:
8.3 TAXI

Inspired by the London Taxi, with numerous ergonomic and comfort advantages for the
passenger as well as for the driver.
Figure 8.3
Specifications: Airbag, air conditioning, 6 seats.
Weight: 750 kg
Maximum
speed:
110 km/h
Maximum
load:
500 Kg
Recharging
time:
Recharging
time:
8.4 PICK-UP

The "pleasure" car: designed for excursions, outdoor sports or water sports. Also suitable
for tradesmen and small businesses.
Figure 8.4
Specifications: Airbag, air conditioning, 2 seats.
Weight: 750 kg
Maximum
speed:
110 km/h
Maximum
load:
500 Kg
Recharging
time:
Recharging
time:
8.5 MINI CAT’S

The smallest and most innovative: three seats, minimal dimensions with the boot of a
saloon: a great challenge for such a small car which runs on compressed air. The Minicat
is the city car of the future.
Figure 8.5
Specifications: Airbag, air conditioning, ABS, 3 seats, 1.5 m3.
Weight: 750 kg
Maximum
speed:
110 km/h
Maximum
load:
270 Kg
Recharging
time:
Recharging
time:

CHAPTER 9
DEVELOPERS & MANUFACTURERS
Various companies are investing in the research, development and deployment of
compressed air cars. Overoptimistic reports of impending production date back to at least
May 1999. For instance, the MDI Air Car made its public debut in South Africa in 2002,
and was predicted to be in production “within six months” in January2004. As of January
2009, the Air Car never went into production in South Africa. Most of the cars under
development also rely on using similar technology to low-energy vehicles in order to
increase the range and performance of their cars.
APUC-: APUC (Association de Promotion des Usages de la Quasi turbine) has made the
APUC Air Car, a car powered by a Quasiturbine.
MDI-: MDI (Motor Development International) has proposed a range of vehicles made
up of Air Pod, One Flow Air, City Flow Air. One of the main innovations of this
company is its implementation of its “active chamber”, which is a compartment which
heats the air (through the use of fuel) in order to double the energy output. This
‘innovation’ was first used in torpedoes in 1904.
Tata Motors-: As of January 2009 Tata Motors of India had planned to launch a car with
an MDI compressed air engine in 2020. In December 2009 Tata’s vice president of
engineering systems confirmed that the limited range and low engine temperatures were
causing problems. Tata motors announced in May 2012 that they have assessed the
design passing phase 1, the “proof of the technical concept” towards full production for
the Indian Market. Tata has moved onto phase 2, “completing detailed development of
the compressed air engine into specific vehicle and stationary applications.”
Air Car Factories SA-: Air Car Factories SA is proposing to develop and built a
compressed air engine. This Spanish based company was founded by Miguel Celades.
Currently there is a bitter dispute between MDI, another firm called Luis which
developed compressed-air vehicles, and Mr.Celades, who was once associated with that
firm.
Like all above more developer &manufacturer are Energine Corporation, Kernelys,
Engineair, Honda, Peugeot/Citroen etc.
Air cars in India:
Tata Motors has signed an agreement with Motor Development International of France to
develop a car that runs on compressed air, thus making it very economical to run and

almost totally pollution free. Although there is no official word on when the car will be
commercially manufactured for India, re-ports say that it will be sooner than later. The
car – Mini CAT - could cost around Rs 350,000 in India and would have a range of
around 300 km between refuels. The cost of a refill would be about Rs 90. In the single
energy mode MDI cars consume around Rs 45 every 100km. Figure 9.1 shows the
proposed air car for India. The smallest and most innovative (three seats, minimal
dimensions with the boot of a saloon), it is a great challenge for such a small car which
runs on compressed air. The Mini CAT is the city car of the future.
Figure 9.1 CAV car in India
OTHER DEVELOPMENTS IN COMPRESSED AIR CAR TECHNOLOGY:
Currently some new technologies regarding compressed air cars have emerged. A
Republic of Korean company has created a pneumatic hybrid electric vehicle car engine
that runs on electricity and compressed air. The engine, which powers a pneumatic-
hybrid electric vehicle (PHEV), works alongside an electric motor to create the power
source. The system eliminates the need for fuel, making the PHEV pollution-free. The
system is con-trolled by an ECU in the car, which controls both power packs i.e. the
compressed-air engine and electric motor. The compressed air drives the pistons, which
turn the vehicle’s wheels. The air is compressed, using a small motor, powered by a 48-
volt battery, which powers both the air compressor and the electric motor. Once
compressed, the air is stored in a tank. The compressed air is used when the car needs a
lot of energy, such as for starting up and acceleration. The electric motor comes to life
once the car has gained normal cruising speed. The PHEV system could reduce the cost
of vehicle production by about 20 per cent, because there is no need for a cooling system,
fuel tank, spark plugs or silencers.

CHAPTER 10
ADVANTAGES AND DISADVANTAGES
11.1 ADVANTAGES
Advantages of vehicles powered by compressed air:
 The costs involved to compress the air to be used in a vehicle are inferior to the costs
involved with a normal combustion engine.
 Air is abundant, economical, transportable, storable and, most importantly, non-
polluting.
 The technology involved with compressed air reduces the production costs of vehicles
with 20% because it is not necessary to assemble a refrigeration system, a fuel tank,
spark plugs or silencers.
 Air itself is not flammable.
 The mechanical design of the motor is simple and robust
 It does not suffer from corrosion damage resulting from the battery.
 Less manufacturing and maintenance costs.
 The tanks used in an air compressed motor can be discarded or recycled with less
contamination than batteries.
 The tanks used in a compressed air motor have a longer lifespan in comparison with
batteries, which, after a while suffer from a reduction in performance.
 Refuelling can be done at home using an air compressor or at service stations. The
energy required for compressing air is produced at large centralized plants, making it
less costly and more effective to manage carbon emissions than from individual
vehicles.
 Reduced vehicle weight is the principle efficiency factor of compressed-air cars.
Furthermore, they are mechanically more rudimentary than traditional vehicles as
many conventional parts of the engine may be omitted. Some plans include motors
built into the hubs of each wheel, thereby removing the necessity of a transmission,
drive axles and differentials. A four passenger vehicle weighing less than 800 lbs. is a
reasonable design goal.
 One manufacturer promises a range of 200 miles by the end of the year at a cost of €
1.50 per fill-up.

 Compressed air engines reduce the cost of vehicle production by about 20%, because
there is no need to build a cooling system, spark plugs, transmission, axles, starter
motor, or mufflers.
 Most compressed air engines do not need a transmission, only a flow control.
 The rate of self-discharge is very low opposed to batteries that deplete their charge
slowly over time. Therefore, the vehicle may be left unused for longer periods of time
than electric cars.
 Compressed air is not subject to fuel tax.
 Expansion of the compressed air lowers in temperature; this may be exploited for use
as air conditioning.
 Compressed-air vehicles emit no pollutants.
 Possibility to refill air tank at home (using domestic power socket).
 Lighter vehicles would result in less wear on roads.
 The price of fuelling air powered vehicles may be significantly cheaper than current
fuels.

11.2 DISADVANTAGES
Just like the modern car and most household appliances, the principle disadvantage is that
of indirect energy use. Energy is used to compress air, which - in turn - provides the
energy to run the motor. Any indirect step in energy usage results in loss. For
conventional combustion motor cars, the energy is lost when oil is converted to usable
fuel - including drilling, refinement, labor and storage. For compressed-air cars, energy is
lost when electrical energy is converted to compressed air.
Further disadvantages:
 According to thermodynamics, when air is expanded in the engine, it cools via
adiabatic cooling and thereby loses pressure, reducing the amount of power passed the
engine at lower temperatures. Furthermore, it is difficult to maintain or restore the
temperature of the compressed or compressing air using a heat exchanger due to the
high rate of flow. The ideal isothermic energy capacity of the tank will therefore not
be realized. Low temperatures may also encourage the engine to ice up.
 Refuelling the compressed air container using a home or low-end conventional air
compressor may take as long as 4 hours. Service stations may have specialized
equipment that may take only 3 minutes.
 Early tests have demonstrated the limited storage capacity of the tanks; the only
published test of a vehicle running on compressed air alone was limited to a range of
7.22 km.

CHAPTER 11
CONCLUSION
The technology of compressed air vehicles is not new. In fact, it has been around for
years. Compressed air technology allows for engines that are both non-polluting and
economical. After ten years of research and development, the compressed air vehicle will
be introduced worldwide. Unlike electric or hydrogen powered vehicles, com-pressed air
vehicles are not expensive and do not have a limited driving range. Compressed air
vehicles are affordable and have a performance rate that stands up to current standards.
To summit up, they are non-expensive cars that do not pollute and are easy to get around
in cities. The emission benefits of introducing this zero emission technology are obvious.
At the same time the well to wheels efficiency of these vehicles need to be improved.
This is a revolutionary engine design which is not only eco-friendly, pollution free, but
also very economical. This addresses both the Problems of fuel crises and pollution.
However excessive research is needed to completely prove the technology for both its
commercial and technical viability.

CHAPTER 12
REFERENCES
1. Gairns J F 1904.Industrial locomotives for mining, factory, and allied uses. Part II.
Compressed air and internal combustion locomotives Cassier's Mag. 16363-77.
2. SAE 1999-01-0623, Schechter.M., “New Cycles for Automobile engines. ISSN:
2456-1843, STUDY AND FABRICATION OF COMPRESSED AIR ENGINE
Ruby Sharma ,Naveen Singla, vol.1, January 2015, pp:27.
3. HE Wei et al. “Performance study on three-stage power system of compressed air
vehicle based on single-screw expander” science china, technological sciences,
August 2010, pp:2299–2303
4. http://www.theaircar.com/
5. http://auto.howstuffworks.com/air-car.htm
6. http://www.planetsave.com/ViewStory.asp?ID=24
7. http://www.evworld.com/databases/shownews
8. www.fadooengineering .com
9. www.youtube .com

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