The Air Car
INTRODUCTION : An engine is a device, which transforms one form of energy into another form. However while transforming energy from one form to another form conversion plays an important role. Normally most of engines convert thermal energy into mechanical work. Heat engine is a device, which transfers the chemical energy into thermal energy, and utilizes this thermal energy to perform useful work. Thus, thermal energy is converted into mechanical energy in a heat engine. A French Formula one engineer Guy Negre who has spent years searching for an alternative to the traditional oil-fuel engine pioneered the compression engine technology. The piston engine is powered by the release of compressed air, which is stored in tanks, very similar to scuba diving tanks attached to the underside of the car.
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The Air Car
PRESENT STATUS: Today all the automobiles, whether bike or a car have an engine that works on either spark ignition system or on compression ignition system depending upon the fuel used. During working of system, it takes fuel and air as input, compresses it to a high pressure and temperature. After compression is over, the charge i.e., fuel and air mixture is ignited by means of spark plug or by direct injection system and gases are produced which are the result of combustion. The gases, obtained as a result of combustion, are at a high temperature and pressure, which work on piston and pushes the piston to bottom dead center (BDC) and when the pressure of gases fall to atmospheric pressure, they are given out to the environment through exhaust valve and by means of exhaust muffler. The gases, which are given out to the environment, consist of a gas like CO2, SO2, etc., which leads to the problem of pollution. Today we know that there are millions of vehicles running on the road. The vehicles pollute the environment and which is very harmful to nature. Due to this increase in pollution, all countries worldwide had laid down an act that after 2020, no vehicle will be promoted to burn-off petrol or diesel as fuel. Also, due to the increasing demand of automobile, there is a shortage of fuel and also the cost of fuel is climbing step by step to high value. We all know that what is the importance of vehicles in our daily life. Everybody needs vehicle in his daily life, because using vehicle his time is reduced from one place to another. Also the transportation of goods from one place to another made simpler with use of vehicle. So depending upon above specification, one can tell that today there is bad need for transportation. There are different methods to avoid pollution problems such as electric cars, solar cars, etc. Certain manufacturers have interested heavily in electric cars generally recommended by public authorities as being solution to urban problems. However the public largely ignores electric cars because, 1. High cost, 2. Limited range, A.E.C.CHIKHLI (2002-2003)
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3. Long recharge time for battery, 4. Negative effect of battery replacement, 5. Difficult recycling processes Another technique which has consumed considerable investments, consist of powering vehicle by fuel cell. But this technique is also largely ignored by public because of, 1. Very high cost, 2. Heavy and complicated structure, 3. Uses of fuel which are in general dangerous and difficult to store To overcome above difficulties, an alternative source is to use an engine that will run on air or gas. Researchers at the University of Washington are developing a new zero-emission automobile propulsion concept that uses liquid nitrogen as the fuel. The principle of operation is like that of steam engine, except there is no combustion involved instead, liquid nitrogen at –323 degF (-196 degC) is pressurized and then vaporized in a heat exchanger by the ambient temperature of the surrounding air. This heat exchanger is like the radiator of a car but instead of using air to cool water, it uses air to heat and boil liquid nitrogen. The resulting high-pressure nitrogen gas is fed to an engine that operates like reciprocating steam engine, converting pressure to mechanical power. The only exhaust is nitrogen, which is the major constituent of our atmosphere.
LN2000’s liquid nitrogen propulsion cycle A.E.C.CHIKHLI (2002-2003)
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The Air Car
The LN2000 is an operating proof-of-concept test vehicle, a converted 1984 Grumman-Olson Kubvan mail delivery van. The engine, a radial five-cylinder 15-hp air motor, drives the front wheels through a five-speed manual Volkswagen transmission. The liquid nitrogen is stored in a thermos-like stainless steel tank, or dewar, that holds 24 gallons and is so well insulated that the nitrogen will stay liquid for weeks. At present the tank is pressurized with gaseous nitrogen to develop system pressure but a cryogenic liquid pump will be used for this purpose in the future. A preheater, called an economizer, uses leftover heat in the engine's exhaust to preheat the liquid nitrogen before it enters the heat exchanger. Two fans at the rear of the van draw air through the heat exchanger to enhance the transfer of ambient heat to the liquid nitrogen. The design of this heat exchanger is such as to prevent frost formation on its outer surfaces.
SCHEMATIC OF LN2000
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WHAT IS AN AIR CAR? : After more than thirty years experience with combustion engines, the French engineer Guy Negre has developed a concept of a totally non pollution engine for use in urban areas. This invention, which uses high-pressure compressed air to store the energy needed for running the engine, is protected worldwide by more than 20 patents owned by MDI. In urban areas, the engine powers a five seat vehicle with a range of approximately 200 km using 300 liters of compressed air stored in either carbon or glass fiber tanks. A compressor driven by an electric motor connected to a standard electric outlet does the recharge of the compressed air tanks. A rapid recharge, using a high-pressure air pump, is also possible. The MDI patents cover not only the basic principal of the utilization of power but also the means of making it economically feasible. Systems for the recuperation of energy have been developed as well as a new power transmission assembly. To demonstrate the viability of the concept, three prototype vehicles equipped with air, mono energy, engines were developed. A taxi called TOP a delivery van and a pickup truck were built. In may 1998, the taxi TOP has been the subject of more than 35 television programs and several hundred newspaper and magazine articles around the world. The potential market for the clean engine concept is immense e.g., vehicles such as taxis, buses, vans, delivery trucks, industrial warehouse tractors, golf buggies, lake or canal boats and many other applications in which fixed engines are primarily used in urban or restricted areas. A version of the MDI engine can, in addition to air, also function with the use of traditional fuel, petrol, diesel, natural or town gas, at very low consumption levels. The change of source of energy is handled electronically based on the speed of the vehicle e.g. below 60 km/h it runs on air and at higher speeds it runs on fuel. The compressed air tanks are recharged while the engine is A.E.C.CHIKHLI (2002-2003)
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The Air Car
running on fuel using a built in mini compressor activated by breaking and deceleration. It is also possible to recharge the air tanks in 2-3 minutes at a compressed air filling station. The French company Zero Pollution Motor Inc. is building a new electric car powered by a compressed-air engine. The car should go on sale in one to three years, at a price of about $10,140 (72,000 francs). The company is calling the car the MDI TOP (Taxi zero Pollution) because they plan to initially introduce it to the public as a taxi. Powered by compressed air and an electric motor, the car will emit only a small amount of pollution, from the oil used to run the motor. The company claims the cars exhaust pollutant levels are much lower than those of a conventional engine are. The engine will run on compressed air stored in either carbon or glass fiber tanks, at a pressure of 4,351 pounds per square inch (psi), or 300 bar. The MDI engine is unlike a conventional four-stroke engine, in which compression, combustion and expansion all take place in a single cylinder. In the MDI engine, these three functions are divided into a three-chamber system, with one cylinder for compression, a small spherical chamber for combustion and a much larger cylinder for expansion. For now, the car is only optimal for city driving because its range is limited to about 124 miles (200 km). Using a household electricity source, it takes about four hours for the motor-driven compressor to recharge the compressed air tanks. A rapid three-minute recharge is also possible, using a highpressure air pump. An alternate version of the MDI engine can function as a duel-fuel engine, using both air and a traditional fuel, such as gasoline, diesel fuel or natural gas, at very low consumption levels. In this engine type, the engine runs on air at speeds below 37 mph (60 kph) and electronically switches to the traditional fuel at higher speeds
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The Air Car
HOW AIR CAR WORKS? : Working principle: Motor development industry had developed a new engine, which is radically a new internal combustion engine. There are two different chambers; one for intake and compression and other for expansion and exhaust; these two chambers are separated from a spherically shaped combustion chamber. The time given for combustion of fuel is 30-100% longer than in comparison with conventional engine thus giving rise to more complete combustion at constant volume, while spherical shape eliminate knocking problem. The untreated exhaust pollutant level are lower than those of conventional engine fitted with a catalyst and engine can be modified to run on petrol, LPG or even diesel. When the speed of car is below 60 km/hr, the air car runs totally on compressed air. While car runs on air out of two chambers only one chamber which is for exhaust and expansion is utilized and other chamber remains idle. Now the compressed air, which is stored in glass fiber tank, is slowly injected in second chamber. This injection of compressed air is handled electronically. As soon as the air enters the second chamber the inlet valve gets closed at same time. The exhaust valve is also closed. Air, which is under a very high pressure, works on piston and piston moves to bottom dead center. The piston is further connected to crank shaft with the help of connecting rod.
Fig. Working principle
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A flywheel is mounted on crankshaft, which stores the energy during expansion. As soon as pressure of air falls to atmospheric pressure the exhaust valve opens and piston moves from bottom dead center to the top dead center, pushes the air to go out to atmosphere through exhaust valve. The energy required during exhaust stroke is supplied by flywheel and cycle is repeated. Now, when speed of car becomes above 60 km/hr, the car runs partially on compressed air and partially on fuel. The air and fuel mixture change is supplied to chamber 1 after proper mixing. The piston in chamber 1 moves to bottom dead center due to which pressure inside the chamber falls below atmospheric pressure and this leads to opening of inlet valve. As soon as charge comes into chamber the inlet and exhaust valves closed and piston moves toward top dead center, which leads to compression of charge. Now charge is at very high pressure and high temperature. This high pressure and high temperature charge is then transferred into combustion chamber where the ignition of charge takes places and exhaust gases which are result of combustion are then given into second chamber. Now in second chamber along with these compressed gases, compressed air is also present. Now both combinedly works on piston and piston moves towards bottom dead center and energy is stored in flywheel, that is supplied during exhaust stroke. During exhaust stroke, exhaust gases are given out to the atmosphere. Thus the cycle is repeated. The change of source is handled electronically based on speed. Thus we see that the car which runs completely on fuel will work totally on fuel and exhaust gases which are given out are more than car which runs partially on air and fuel because the power is obtained partially from compressed air and partially from the exhaust gases. The amount of exhaust gases are 50 to 70% less in case of air car than the present day cars. Hence air car is the best solution for pollution problem and also for the increasing cost of fuel problem.
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The Air Car
In practical terms compressed air at 300 bars is stored in the carbon fiber tanks A. 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 compressed air now passes to the motor E. where a two more stages of decompression and re-heating 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. A.E.C.CHIKHLI (2002-2003)
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The Air Car
POWER -TORQUE GRAPH
30 25 7 6 5 4 3 2 1 0
20 15 12 5 0
500
1000
1500
2000
2500
3000
0 3500
The blue curve indicates the horsepower. The red curve indicates the engine torque in Kgm. Both curves depend on rpm (Below in black). One can appreciate that the engine torque is very high at low revolutions (more than 6 Kgm at 750 revolutions). It is to say that to the same revolution that a normal engine gives, the MDI car gives all its engine torque. This high torque stays at practically its maximum of 2,800 revolutions. As well we can see that the engine works at a lower revolution than a normal car, giving its maximum power of 3,500 rpm.
FILLING UP: The designers say it will be possible to merely plug the vehicle into any electrical power source to fill it up. That could take up to 4 hrs but the manufacturers imagine that fleet owners could install their own air stations, where a fill up could take as little as 3 min. 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. A.E.C.CHIKHLI (2002-2003)
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The Air Car
REASONS FOR BUYING AIR CAR •
The vehicle is completely pollution free, with an autonomy of some 200 km and a top speed of 110 km/h.
•
Its engine runs on compressed air and ambient air - the air we breath, with no risk of either of explosion or from toxic fumes.
•
The tanks, storing the compressed air , can be refilled by a built-in compressor in 3-4 hours, using a standard 110/220 V electrical outlet, or in 2-3 minutes at an air compressor equipped service station.
•
Included in the vehicle is a system for recuperating ambient thermal energy.
•
Free air conditioning in warm weather; a clean, non-polluting heating system in cold weather.
•
Simplified, low cost maintenance, owing to the engine's low operating temperature, e.g. oil change (2 litres of vegetable oil) every 50,000 km.
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The Air Car
SPECIFICATION: Intake and compression cylinder
230 cubic cm
Expansion and exhaust cylinder
500 cubic cm
Power max. HP (KW)
25 (18.3) at 3000 rpm
Torque max. Kgm (Nm)
6.3 (61.7) at 500-2500 rpm
Power source
electronically injected compressed
air Oil volume and oil change interval
0.8 liters and about 50,000 km
Vehicle
engine mount
Rear
Transmission
Automatic, continuous variation
Rear wheel drive
Suspension
Front coil spring, rear pneumatic
Steering
Rack and pinion
Dimensions
Length 384 cm, width 182 cm, height 175cm
Wheel base
292 cm
Weight: unload
About 700 kg
Chassis and body materials
Steel bars/honeycomb plastic and
fiber glass Tanks for compressed air
Thermoplastic lining and carbon
fiber Fuel
Compressed air 300 bar
Time for recharge of compress air tanks: Using household electricity source
4 hours
Using air service station
3 minutes
Maximum speed
60 mph
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The Air Car
HOW AIR-CAR HELPS TO REDUCE POLLUTION: In most of the countries gas pollution is main problem which is caused due to the use of gasoline as a fuel in vehicles. Gasoline is a liquid formed purely of carbon and hydrogen. Gasoline is made up of carbon chains of different lengths ranging from C7H16 to C11H24. If you could burn gasoline as a vapour with a hot flame and plenty of oxygen, you would get nearly pure carbon dioxide and water as the combustion products. And as you know that complete combustion of fuel does not takes place, reason behind this is that air supplied during combustion is little less than that required for complete combustion. This incomplete combustion causes carbon monoxide to liberate as a biproduct which directly attacks the ozone layer and reason for many diseases. The most important pollutants in car exhaust include: 1) Carbon monoxide is formed because combustion is incomplete. Not enough oxygen is available fast enough to react completely with all of the carbon available. 2) Nitrogen oxides - Because of the pressure and temperature inside a cylinder, nitrogen and oxygen in the air combine in various ways. 3) Unburned hydrocarbons - not all of the hydrocarbons participate in the reaction because there is so little time available during the combustion phase. 4) There can also be some impurities like sulphur in the gas that form sulphur oxides. Now many of automobile producing companies they uses catalytic converter to avoid above gases to go to atmosphere. The idea behind a catalytic converter is to try to eliminate the carbon monoxide, nitrous oxides and hydrocarbons by reacting them with plenty of oxygen on a platinum catalyst. However, catalytic converters are not perfect, so some of the pollutants escape. On hot summer days we see the effect of these pollutants in the form of smog and ozone. As about gasoline is the main source of pollution, if we use compressed air instead of gasoline then we can improve environment. As we A.E.C.CHIKHLI (2002-2003)
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The Air Car
know that nitrogen is the main constituent of environment, in case of air car we extract nitrogen from environment, liquify it and used as fuel in car, then there will be nitrogen, only the exhaust gas which is not harmful to human being and environment. By using liquid nitrogen (compressed air) in car, we can reduce pollution up to 70-80%.
1. Based on 45% highway driving, 55% city driving, 15000 annual miles and the following fuel prices. Electricity .$0.08 per k.w./hour ($2.71 per gallon of gasoline equivalent) MPG represents the number of miles that can be traveled using an amount of electricity equivalent to the energy in a gallon of gasoline. 2. GHG. Greenhouse gas emissions expressed in CO2 equivalents. Estimates include the full fuel cycle and exclude vehicle manufacture.(U.S. Department of Energy, GREET Model, Argonne National Laboratory) Nissan and Toyota MPG/GHG/Range/Fuel Cost Figures based on DOT reported figures, City C.A.T. provided by MDI 3. Based on a 1998 Test conducted by EVA America 4. Three minutes at High Speed Compressor/4 Hrs on Conventional 220 Volt home charger
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The Air Car
CONSIDERATION OF SAFETY: One may have question in mind that storing of air at such high pressure will cause some serious problem. The tank, which is made up of glass fiber, is used to store the air under high pressure. Glass fiber tank can withstand such high pressure. Second problem is that what will happen in an accident? Don’t worry Alone will confiscate everyone’s gas burning cars and issue every one an air car (Complete with statement of the art satellite tracking system). So that all the collision can be prevented from the space. Third question is from where you will fill air where there is no air station. The designer of the engine says that it will be possible to merely plug the vehicle into any electrical power source to it. That could take 4 hours. This engine has a small in-built compressor that compresses air and stores it in tanks. To withstand such an high pressure, the cylinder, the piston and connecting rod have been redesigned as well as new power transmission assembly had been developed. One may ask a question that Can a MDI engine adopted to my car? Answer for this is that the MDI engine can not be installed into classical vehicles, due to the fact that they generally do not hold enough space as to fit the air tanks, with a length of 2.10 m and a diameter of 23 cm.
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The Air Car
ADVANTAGES: 1. Avoidance of knocking phenomenon, due to the presence of spherical cylinder, 2. Avoidance of cooling arrangement Radiator fans etc., 3. Can run on air as well as fuel, 4. The initial cost is low, 5. Operating cost is also very low, 6. Reduce pollution up to 50-70% while running on normal speed.
DISADVANTAGES: 1. On board compressor takes more time to refill the tanks i.e. 3 to 4 hours. 2. Autonomy range depends on speed of car. At 50km/hr autonomy is over 300 km, but at
100 km/hr it reduces to 1/3 of it.
3. You have to keep liquid fuel (petrol or diesel ) also with you for higher speed driving .
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FUTURE SCOPE: The motor development industry (MDI) had tried to develop an engine for bikes. They were successful in developing engine for bikes running on compressed air. After year 2003 they will also introduced a bike that will run on compressed air so that is much reduce in air pollution. In most of the countries, gas pollution is the main problem of pollution. The vehicle, whether it is bike or car, is the main source of pollution. Use of air motor can reduce this problem of pollution we can keep the environment pollution-free. The cost of fuel (gasoline like petrol, etc.) is also climbing to high value, and this is becoming headache for motor owner. By using air motor we can save the fuel and minimize the expenditure.
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The Air Car
CONCLUSION: From all the description made here one can say that by using air car there is reduction in air pollution in great extent. Also, the aim of project is to cut cost, create job locally. Also air car provides an answer to the shortage of fuel and high price of fuel. With petrol and diesel prices going up and the price of oil subjects to fluctuation for motorist, this becomes headache; use of air motor is only the solution. All know that there will be shortage of gasoline (petrol, diesel), in future, engine that runs on compressed air is only the alternative for it.
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BIBLIOGRAPHY : 1)
www.zeropollution.com
2)
www.howstuffworks.com
3)
www.theaircar.com
4) www.e.volution.com
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