SELF STUDY PROJECT AUTOMOBILE ENGINEERING 2nd year STUDY OF COMPRESSED AIR VEHICHLE
BY: HARMINDER DHILLON: 2K12/AE/037 HARSHIT DHAWAN: 2K12/AE/038 ISHAN AGGARWAL: 2K12/AE/039 ISHANT MEHTA: 2K12/AE/040 JALAJ SINGH: 2K12/AE/041 Jishnu Mitra: 2K12/AE/045
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ABSTRACT
In this modern era we want more comfortable life & to achieve this, there are many inventions and researches are going on in the field of engineering but as each action having there some opposite reaction that may be good or bad. Some achievements may lead to problems in future and one of these achievements is fossil fuel engines which were a good achievement for us before 30-40 years but now they are one of the sources of contributor of global warming and pollution with fossil fuel crises. To cope up with this problem we have to use such engines which emits less or zero COx & NOx particles, for that one of the solutions is hybrid electrical vehicle but again they emit some COx & NOx so this is not a complete solution for this problem. The best feasible solution is Zero Emission Vehicle i.e. Compressed Air Technology (CAT) which does not require any type of fossil fuel. The gasoline-powered engine requires 4 Rs/mile whereas for air powered engines it is 75% less i.e. 1 Rs/mile with no emission CO x & NOx pollutants. The cost the hybrid electric vehicle is approximately $50,999 which requires the charging period of 5 to 6 hours whereas the cost of air powered vehicle $14,000 i.e. less than half which requires only 3 to 4 minutes for recharging.
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CERTIFICATE
This is to certify that the dissertation entitled “STUDY OF COMPRESSED AIR VEHICLE” is submitted by combined efforts of following:
1. JALAJ SINGH 2. ISHANT MEHTA 3. HARSHIT DHAWAN 4. HARMINDER 5. ISHAN AGGARWAL 6. JISHNU MITRA
For SELF STUDY project. It is also to certify that this project is made for B.Tech in AUTOMOBILE ENGINEERING.
Teacher concerned:
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ACKNOWLEDGEMENTS “Every day I remind myself that my inner and outer life depends on the labor of other man”- Albert Einstein. Acknowledgment is not a mere obligation but an epitome of humility and indebtness to all those who helped in the compilation of this project and without whom our project would have been anything but presentable.
This is to thank our sincere and respected Professor concerned for inspiring and enthusiastic guidance throughout this project.
Lastly but most important, we would like to pay our utmost regards to our beloved parents and faculty members for their blessing without which success is a mirage. To conclude we would like to quote the following words by Sigmund feud“Don’t mix excellence with perfection. Excellence, I can reach for, perfection is gods business”
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CONTENTS Topic
Page No.
1. Compressed Air Vehicle Basics
1.1 Introduction
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1.2 History
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1.3 Applications
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1.4 Advantages
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1.5 Disadvantages
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2. Constructional Details
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2.1 Engine & pneumatic engine and application
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2.2 Tanks
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2.3 Compressed air
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2.4 Emission output
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3. Working
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3.1 Process description
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3.2 Comparison with Electrical Vehicle
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4. Possible Improvement
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5. Developers and Manufacturers
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6. Conclusion
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7. Bibliography 20
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1. 1 Introduction A Compressed-air engine is a pneumatic actuator that creates useful work by compressed air. A compressed-air vehicle is powered by an air engine, using compressed air, which is stored in a tank. Instead of mixing fuel with air and burning it in the engine to drive pistons with hot expanding gases, compressed air vehicles (CAV) use the expansion of compressed air to drive their pistons. They have existed in many forms over the past two centuries, ranging in size from hand held turbines up to several hundred horsepower. For example, the first mechanically-powered submarine, the 1863 Plongeur, used a compressed air engine. The laws of physics dictate that uncontained gases will fill any given space. The easiest way to see this in action is to inflate a balloon. The elastic skin of the balloon holds the air tightly inside, but the moment you use a pin to create a hole in the balloon's surface, the air expands outward with so much energy that the balloon explodes. Compressing a gas into a small space is a way to store energy. When the gas expands again, that energy is released to do work. That's the basic Principle behind what makes an air car go. Some types rely on pistons and cylinders, others use turbines. Many compressed air engines improve their performance by heating the incoming air, or the engine itself. Some took this a stage further and burned fuel in the cylinder or turbine, forming a type of internal combustion engine. One manufacturer claims to have designed an engine that is 90 percent efficient. Compressed air propulsion may also be incorporated in hybrid systems, e.g., battery electric propulsion and fuel tanks to recharge the batteries. This kind of system is 6
called hybrid-pneumatic electric propulsion. Additionally, regenerative braking can also be used in conjunction with this system.
1.2 History (a) The first compressed-air vehicle was devised by Bompas, a patent for a locomotive being taken out in England in 1828. There were two storage tanks between the frames, with conventional cylinders and cranks. It is not clear if it was actually built. (Knight, 1880) (b) The first recorded compressed-air vehicle in France was built by the Frenchmen Andraud and Tessie of Motay in 1838. A car ran on a test track at Chaillot on the 9th July 1840, and worked well, but the idea was not pursued further.
Fig: 1.1
(c) In 1848 Barin von Rathlen constructed a vehicle which was reported to have been driven from Putney to Wandsworth (London) at an average speed of 10 to 12 mph. (d) At the end of 1855, a constructor called Julienne ran some sort of vehicle at Saint-Denis in France, driven by air at 25 atmospheres (350 psi), for it to be used in coal mines.
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(e) Compressed air locomotives were use for haulage in 1874 while the Simplon tunnel was being dug. An advantage was that the cold exhaust air aided the ventilation of the tunnel. (f) Louis Mékarski built a standard gauge self-contained tramcar which was tested in February 1876 on the Courbevoie-Etoile Line of the Paris Tramways Nord (TN), where it much impressed the current president and minister of transport Maréchal de MacMahon. The tramcar was also shown at the exhibition of 1878 as it seemed to be an ideal transport method, quiet, smooth, without smoke, fire or the possibility of boiler explosion. (g) The compressed-air locos were soon withdrawn due to a number of accidents, possibly caused by icing in the pipes of the brakes, which were also worked by compressed air. (h) In Louis Mékarski built a standard gauge self-contained tramcar which was tested in February 1876 on the Courbevoie-Etoile Line of the Paris Tramways Nord (TN), where it much impressed the current president and minister of transport Maréchal de MacMahon. The tramcar was also shown at the exhibition of 1878 as it seemed to be an ideal transport method, quiet, smooth, without smoke, fire or the possibility of boiler explosion.
Fig 1.2 The Victor Tatin airplane of 1879 used a compressed-air engine for propulsion
1.3 Applications
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The compressed air engine can be used in many vehicles. Some of its applications to be used as engine for vehicles are: (a) Mopeds Jem Stansfield, an English inventor has been able to convert a regular scooter to a compressed air moped. This has been done by equipping the scooter with a compressed air engine and air tank. (b) Buses MDI makes MultiCATs vehicle that can be used as buses or trucks. RATP has also already expressed an interest in the compressed-air pollution-free bus. (c) Locomotives Compressed air locomotives have been historically used as mining locomotives and in various areas. (d) Trams Various compressed-air-powered trams were trialed, starting in 1876 and has been successfully implemented in some cases. (e) Watercraft and aircraft Currently, no water or air vehicles exist that make use of the air engine. Historically compressed air engines propelled certain torpedoes.
1.4 Advantages The advantages 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. Their potential advantages over other vehicles include: (a) Much like electrical vehicles, air powered vehicles would ultimately be powered through the electrical grid, which makes it easier to focus on reducing pollution from one source, as opposed to the millions of vehicles on the road. (b) Transportation of the fuel would not be required due to drawing power off the electrical grid. This presents significant cost benefits. Pollution created during fuel transportation would be eliminated. (c) Compressed air technology reduces the cost of vehicle production by about 20%, because there is no need to build a cooling system, fuel tank, Ignition Systems or silencers. (d) Air, on its own, is non-flammable.
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(e) High torque for minimum volume. (f) The mechanical design of the engine is simple and robust. (g) Low manufacture and maintenance costs as well as easy maintenance. (h) Compressed-air tanks can be disposed of or recycled with less pollution than batteries. (i) Compressed-air vehicles are unconstrained by the degradation problems associated with current battery systems. (j) The tank may be able to be refilled more often and in less time than batteries can be recharged, with re-fuelling rates comparable to liquid fuels. (k) Lighter vehicles would mean less abuse on roads. Resulting in longer lasting roads. (l) The price of fuelling air-powered vehicles will be significantly cheaper than current fuels.
1.5 Disadvantages Like the modern car and most household appliances, the principal disadvantage is the indirect use of energy. Energy is used to compress air, which - in turn - provides the energy to run the motor. Any conversion of energy between forms results in loss. For conventional combustion motor cars, the energy is lost when oil is converted to usable fuel - including drilling, refinement, labour, storage, eventually transportation to the end-user. For compressed-air cars, energy is lost when electrical energy is converted to compressed air. (a) When air expands, as it would in the engine, it cools dramatically (Charles law) and must be heated to ambient temperature using a heat exchanger similar to the Intercooler used for internal combustion engines. The heating is necessary in order to obtain a significant fraction of the theoretical energy output. The heat exchanger can be problematic. While it performs a similar task to the Intercooler, the temperature difference between the incoming air and the working gas is smaller. In heating the stored air, the device gets very cold and may ice up in cool, moist climates. (b) Refueling the compressed air container using a home or low-end conventional air compressor may take as long as 4 hours though the specialized equipment at service stations may fill the tanks in only 3 minutes.
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(c) Tanks get very hot when filled rapidly. SCUBA tanks are sometimes immersed in water to cool them down when they are being filled. That would not be possible with tanks in a car and thus it would either take a long time to fill the tanks, or they would have to take less than a full charge, since heat drives up the pressure. (d) 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. (e) A 2005 study demonstrated that cars running on lithium-ion batteries outperform both compressed air and fuel cell vehicles more than three-fold at same speeds. MDI has recently claimed that an air car will be able to travel 140km in urban driving, and have a range of 80 km with a top speed of 110km/h on highways, when operating on compressed air alone.
2. CONSTRUCTIONAL DETAILS
Fig.2.1:- Chassis of air powered car In practical terms compressed air at 300 bars is stored in the carbon fibre tanks A. The air is released through the main line firstly to an alternator B where the first stage of decompression takes place. The now cold air passes through a heat exchanger C which adds thermal energy to the air and provides a convenient opportunity for air conditioning D. The warmed
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compressed air now passes to the motor E. where a two more stages of decompression and reheating take place. The motor drives the rear axle G through the transmission F. Control of engine speed is through a conventional accelerator pedal H controlling a valve within the motor.
An energy recycler J is under test which uses engine braking K to recompress air during braking into a secondary storage facility, providing additional energy for re-start and acceleration. Conventional hydraulic braking L is supplied. The vehicle can be refilled by using the onboard compressor M or by refilling the tank at an air station at N. Ultimately the engine generates 37 Kilowatts, notwithstanding the small size of this unit.
The "exhaust" leaves the engine at about zero degrees Celsius, a result of the expansion and cooling action. The exhaust is totally pure and fit to breathe. A compressed air driven engine offers enormous benefits to the car designer. Because of its small size and weight, and the removal of a host of devices and parts not required, the designer has free rein to maximize his materials and space to provide a simple, economic platform for the vehicle.
2.1 Engine & pneumatic engine and application
Fig.2.2 Pneumatic hybridization of Diesel Engine
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A pneumatic motor or compressed air engine is a type of motor which does mechanical work by expanding compressed air. Pneumatic motors generally convert the compressed air energy to mechanical work through either linear or rotary motion. Linear motion can come from either a diaphragm or piston actuator, while rotary motion is supplied by either a vane type air motor or piston air motor. Pneumatic motors have existed in many forms over the past two centuries, ranging in size from handheld turbines to engines of up to several hundred horsepower. Some types rely on pistons and cylinders; others use turbines. Many compressed air engines improve their performance by heating the incoming air or the engine itself.
2.2 Tanks The storage vessel is often an underground cavern created by solution mining (salt is dissolved in water for extraction) or by utilizing an abandoned mine; use of porous rock formations such as those in which reservoirs of natural gas are found has also been studied. Plants operate on a daily cycle, charging at night and discharging during the day. Heating of the compressed air using natural gas or geothermal heat to increase the amount of energy being extracted has been studied by the Pacific Northwest National Laboratory
Fig. 2.3 Compressed Air Cylinder
Compressed air energy storage can also be employed on a smaller scale such as exploited by air cars and air-driven locomotives, and also by the use of high-strength carbon-fiber air storage tanks. However, when compressed air is stored at room temperature this stored air, in general, contains the same amount of energy per pound as uncompressed room temperature air. The considerable amount of energy used to compress this air is not stored there if the air is allowed to reduce to room temperature. Therefore, to obtain substantial energy from the expansion of this stored room temperature compressed air a heat reservoir must be provided to supply the needed energy. This can be challenging in mobile applications.
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2.3 Compressed Air Compressed air has a low energy density. In 300 bar containers, about 0.1 MJ/L and 0.1 MJ/kg is achievable, comparable to the values of electrochemical lead-acid batteries. While batteries can somewhat maintain their voltage throughout their discharge and chemical fuel tanks provide the same power densities from the first to the last litre, the pressure of compressed air tanks falls as air is drawn off. A consumer-automobile of conventional size and shape typically consumes 0.3–0.5 kWh (1.1–1.8 MJ) at the drive shaft per mile of use, though unconventional sizes may perform with significantly less.
2.4 Emission output Like other non-combustion energy storage technologies, an air vehicle displaces the emission source from the vehicle's tail pipe to the central electrical generating plant. Where low emissions sources are available, net production of pollutants can be reduced. Emission control measures at a central generating plant may be more effective and less costly than treating the emissions of widely dispersed vehicles. Since the compressed air is filtered to protect the compressor machinery, the air discharged has less suspended dust in it, though there may be carry-over of lubricants used in the engine.
3. Working In principle the technology is very similar to the internal combustion system in that compressed air is used to drive a piston in a barrel. The secret of the engine lies in the way it efficiently converts the energy stored in the tanks of compressed air. By way of explanation, it has long been known that to compress air to high pressures a staged process should be used, compressing air to first 50 bars, then to 150 bars then three hundred and so on. This technique, commonly employed by the air and gas liquefaction industries, uses a fraction of the energy used to compress the gas in one operation. The secret of the compressed air motor is simply to reverse the process - decompress the air in stages and in so doing efficiently release energy at each point in the chain.
3.1 PROCESS DESCRIPTION
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1. The first piston takes in ambient air compressed it to approximately 300psi and 200°F in the compression chamber during the first cycle of engine
Fig.3.1 working of air operated engine
2. When the piston pauses, a small amount of compressed air from the tanks is released into the expansion chamber to create a low pressured, low temperature volume of about 140 psi. 3. Shortly before the valve to the expansion cylinder is opened a high-speed shutter connects the compression and expansion chambers this sudden pressure and temperature difference between the two chambers creates pressure waves in the expansion chamber, thereby producing work in the expansion cylinder that drives the piston to power the engine The air tanks for storing the compressed are located underneath the vehicle they are constructed of reinforced carbon fiber with a thermoplastic liner each tank can held 3180 ft 3 of air at a pressure of up to 4,300 psi when connected to a special compressor station the tanks can be recharged within 3-4 mints they can also be recharged using the on-board compressor within 3-4 hours after connection to standard power outlet.
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To
Fig.3.2 flow of air tank to exhaust
Compensate for the cooling effect that takes place, a thermal exchanger heats the compressed air using the warmth of external air. This process is repeated as many times as possible to extract the maximum energy efficiency from the compressed air. For the somewhat technically minded, the following drawing illustrates the theoretical explanation for this process.
3.2 COMPARISON WITH ELECTRICAL VEHICLES
Fig 3.3 Comparison between air car and electric vehicle 16
Compressed-air vehicles are comparable in many ways to electric vehicles, but use compressed air to store the energy instead of batteries. Their potential advantages over other vehicles include:
Much like electrical vehicles, air powered vehicles would ultimately be powered through the electrical grid. Which makes it easier to focus on reducing pollution from one source, as opposed to the millions of vehicles on the road
Transportation of the fuel would not be required due to drawing power off the electrical grid. This presents significant cost benefits. Pollution created during fuel transportation would be eliminated. Compressed-air technology reduces the cost of vehicle production by about 20%, because there is no need to build a cooling system, fuel tank, Ignition Systems or silencers.
The engine can be massively reduced in size
The engine runs on cold or warm air, so can be made of lower strength light weight material such as aluminium, plastic, low friction teflon or a combination.
Low manufacture and maintenance costs as well as easy maintenance.
Compressed-air tanks 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.
The air tank may be refilled more often and in less time than batteries can be recharged, with refilling rates comparable to liquid fuels.
Lighter vehicles cause less damage to roads, resulting in lower maintenance cost.
The price of filling air powered vehicles is significantly cheaper than petrol, diesel or biofuel. If electricity is cheap, then compressing air will also be relatively cheap.
4. Possible Improvements
Compressed-air vehicles operate to a thermodynamic process as air cools down when expanding and heats up when being compressed. As it is not possible in practice to use a theoretically ideal process, losses occur and improvements may involve reducing these, e.g., by using large heat exchangers in order to use heat from the ambient air and at the same time provide air cooling in the passenger compartment. At the other end, the heat produced during compression can be stored in water systems, physical or chemical systems and reused later.
It may be possible to store compressed air at lower pressure using an absorption material within the tank. Absorption materials such as Activated carbon, or a metal organic
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framework is used to store compressed natural gas at 500 psi instead of 4500 psi, which amounts to a large energy saving
5. Developers and 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 January 2004. 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. APUQ APUQ (Association de Promotion des Usages de la Quasiturbine) has made the APUQ Air Car, a car powered by a Quasiturbine.
MDI MDI has proposed a range of vehicles made up of AirPod, OneFlowAir, CityFlowAir, MiniFlowAir and MultiFlowAir. 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 a 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 2011.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 build a compressed air engine. This Spanish based company was founded by Miguel Celades. Currently there is a bitter dispute between Motor Development International, another firm called Luis which developed compressed-air vehicles, and Mr. Celades, who was once associated with that firm.
Energine The Energine Corporation was a South Korean company that claimed to deliver fully assembled cars running on a hybrid compressed air and electric engine. These cars are more precisely named pneumatic-hybrid electric vehicles. Engineers from this company made, starting from a Daewoo Matiz,
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a prototype of a hybrid electric/compressed-air engine (Pne-PHEV, pneumatic vehicle the compressed-air engine is used to activate an alternator, which extends the autonomous operating capacity of the car. A similar concept using a pneumatic accumulator in a largely hydraulic system has been developed by U.S. government research laboratories and industry. It uses compressed air only for recovery of braking energy, and in 2007 was introduced for certain heavy vehicle applications such as refuse trucks.
Honda
Fig.4.1 PSA Peugeot Citroën Hybrid Air concept exhibited at the 2013 Geneva Motor Show.
In 2010, Honda presented the Honda Air concept car at the LA Auto Show.
Kernelys The "K'Airmobiles" project of Kernelys aimed to produce commercial vehicles in France. The project was started in 2006-2007 by a small group of researchers. They said to be working on 2 types of vehicles; namely "VPA" (Vehicles with Pneumatic Assistance) and "VPP" (Vehicles with Pneumatic Propulsion) vehicles. However, the project has in the end not been able to gather the necessary funds to go commercial. People should note that, meantime, the team has recognized the physical impossibility to use onboard stored compressed air due to its poor energy capacity and the thermal losses resulting from the expansion of the gas. These days, using the patent pending 'K'Air Fluid Generator', converted to work as a compressed-gas motor, the company has reworked its project in 2010 together with a North American group of investors, now intended for the purpose of developing a green energy power system.
Engineair Engineair is an Australian company which manufactures small industrial vehicles using an air engine of its own design.
Peugeot/Citroën Peugeot and Citroën have announced that they too are building a car that uses compressed air as an energy source. However, the car they are designing uses a hybrid system which also uses a gasoline 19
engine (which is used for propelling the car over 70 km/h, or when the compressed air tank has been depleted.
6. CONCLUSION Nowadays the earth is facing the biggest problem of global warming. The major cause for this is the environmental pollution. Fossil fuel vehicles are the major contributors to this pollution. In order to irradiate this problem the solution is hybrid electrical vehicles but again they emit some pollutants, hence it is not a complete solution. The compressed air technology i.e. zero emission vehicles is the best feasible alternative and hence the complete solution of this problem.
7. Bibliography
http://www.theaircar.com/
http://auto.howstuffworks.com/air-car.htm
http://www.planetsave.com/ViewStory.asp?ID=24
http://www.evworld.com/databases/shownews.cfm?pageid=news040303-06 20
http://news.bbc.co.uk/1/hi/world/europe/2281011.stm
htto://zevcat.com/
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