25-07-2014, 02:27 PM
AIR CAR
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Abstract
The Air car is a car currently being developed and, eventually, manufactured by Moteur Developpement International (MDI), founded by the French inventor Guy Nègre. It will be sold by this company too, as well as by ZevCat, a US company, based in California.
The air car is powered by an air engine, specifically tailored for the car. The used air engine is being manufactured by CQFD Air solution, a company closely linked to MDI.
The engine is powered by compressed air, stored in a glass or carbon-fibre tank at 4500 psi. The engine has injection similar to normal engines, but uses special crankshafts and pistons, which remain at top dead center for about 70% of the engine's cycle; this allows more power to be developed in the engine.
Though some consider the car to be pollution-free, it must be taken into account that the tanks are recharged using electric (or gasoline) compressors, resulting in some pollution, if the electricity used to operate the compressors comes from polluting power plants (such as gas-, or coal-power plants). Solar power could possibly be used to power the compressors at fuel station.
Introduction
An Air Car is a car that can run on compressed air alone without the use of conventional fuels used in present day automobiles. The car is powered by an air engine. The air engine is an emission-free piston engine using compressed air. The engines are similar to steam engines as they use the expansion of externally supplied pressurised gas to perform work against a piston.
For practical application to transportation, several technical problems must be first addressed:
• As the pressurised air expands, it is cooled, which limits the efficiency. This cooling reduces the amount of energy that can be recovered by expansion, so practical engines apply ambient heat to increase the expansion available.
• Conversely, the compression of the air by pumps (to pressurise the tanks) will heat the air. If this heat is not recovered it represents a further loss of energy and so reduces efficiency.
• Storage of air at high pressure requires strong containers, which if not made of exotic materials will be heavy, reducing vehicle efficiency, while exotic materials (such as carbon fibre composites) tend to be expensive.
• Energy recovery in a vehicle during braking by compressing air also generates heat, which must be conserved for efficiency.
• It should be noted that the air engine is not truly emission-free, since the power to compress the air initially usually involves emissions at the point of generation.
This most recent development using pressurized air as fuel in an engine was invented by Guy Nègre, a French engineer. In 1991 the inventor Guy Nègre started up Moteur Developpement International (MDI), Luxembourg and invented a dual-energy engine running on both compressed air as on regular fuel. From this moment on he managed to create a compressed air only-engine, and improved his design to make it more powerful. In the 15 years he's been working on this engine, considerable progress has been made: the engine is now claimed to be competitive with modern ICEs. It is probably still not as powerful as an ICE (although depending on which model of air engine vs model ICE). Proponents claim that this is of little importance since the car can simply be made lighter, or the tanks be put on a higher pressure (psi-level), pushing the engine to above a comparable ICE- engine.
Other people that have been working on the idea are Armando Regusci and Angelo Di Pietro. They too have companies, Rugusci started up Regusci Air and Di Pietro started up Engine Air. They are selling their engines.
Engine Design
It uses the expansion of compressed air to drive the pistons in a modified piston engine. Efficiency of operation is gained through the use of environmental heat at normal temperature to warm the otherwise cold expanded air from the storage tank. This non-adiabatic expansion has the potential to greatly increase the efficiency of the machine. The only exhaust gas is cold air (−15 °C), which may also be used for air conditioning in a car. The source for air is a pressurized glass or carbon-fiber tank holding air at around 3,000 lbf/in² (20 MPa). Air is delivered to the engine via a rather conventional injection system. Unique crank design within the engine increases the time during which the air charge is warmed from ambient sources and a two stage process allows improved heat transfer rates.
The Armando Regusci's version of the air engine has several advantages over the original Guy Nègre's one. In the initial Guy Nègre's air engine, one piston compresses air from the atmosphere, holding it on a small container that feeds the high pressure air tanks with a small amount of air. Then that portion of the air is sent to the second piston where it works. During compression for heating it up, there is a loss of energy due to the fact that it cannot receive energy from the atmosphere as the atmosphere is less warm than it. Also, it has to expand as it has the crank. The Guy Nègre's air engine works with constant torque, and the only way to change the torque to the wheels is to use a pulley transmission of constant variation, losing efficiency. In the Regusci's version, the transmission system is direct to the wheel, and has variable torque from zero to the maximum with all the efficiency. When vehicle is stopped, Guy Nègre's engine has to be on and working, losing energy, while the Regusci's version has not.
An overview of the air car
The technology that MDI vehicles use is not new, in fact it had been around for years. Compressed air technology allows for engines that are both non polluting and economical. After ten years of research and development, MDI is prepared to introduce its clean vehicles onto the market. Unlike electric or hydrogen powered vehicles, MDI vehicles are not expensive and do not have a limited driving range. MDI cars are affordable and have a performance rate that stands up to current standards. To sum it up, they are non-expensive cars that do not pollute and are easy to get around cities in.
Two technologies have been developed to meet different needs:
Single energy compressed air engines
Dual energy compressed air plus fuel engines
The single energy engines will be available in both Minicats 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 by using the car’s on board computer. The vehicles do not have normal speed gauges. Instead, they will have a small computer screen that shows the speed and engine revolutions. The system allows for infinite possibilities such as GSM telephone systems, GPS satellite tracking systems, programs for delivery people, emergency systems, internet connections, voice recognitions, map presentation, traffic information... in three words: the future is now.
The Basic Principle of the CAT’s 34 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.
Commercialization
As soon as the MDI engines and vehicles are commercially viable (within 1-3
years, depending on the version) they will have a market, with very limited
competition, if any, for an estimated period of 10-15 years.
The commercial strategy is currently concentrated on the urban markets, with
products including taxis, delivery vans and pickup trucks.
Based on a new concept of local vehicle production and sales, MDI promote
regional manufacturing license rights in the form of franchised turnkey factory
systems. Such a turnkey factory will have a normal production capacity of
2000-4000 vehicles per year and will employ some 130 people. A model factory is
being constructed in Brignoles, France.
A taxi called "TOP" (Taxi ZerO Pollution) and pickups truck, were built. In May
1998, the first road tests of these prototypes were done in Brignoles, France.
A great interest in the zero pollution concept has been expressed by the news
media. Since May 1998, the taxi "TOP" has been the subject of more than 40
television programs and several newspaper and magazine articles around the
Conclusion
The air car which is the result of a long research and development is a clean, easy to drive, high performance car. MDI has achieved what the large car manufactures have promised in a hundred years time.
The end product is a light weight vehicle that can reach speeds up to 220 km/h (even though the legal limit is 120), a product that does not pollute like twentieth century vehicles and does not take a lifetime to pay off. Essentially, MDI has developed a modern, clean, and cheap car that meets most people’s needs.
The principle advantages for an air powered vehicle are:
• Fast recharge time
• Long storage lifetime (electric vehicle batteries have a limited useful number of cycles, and sometimes a limited calendar lifetime, irrespective of use).
• Potentially lower initial cost than battery electric vehicles when mass produced.