Final Year Project by: -Krunal Ariwala (U09ME750) -Preetam Gupta ( U09ME757) -Harmanpreet Singh (U09ME760) -Kishor Kumar Sau (U09ME770) -Nikunj Pareek (U09ME791)
History of Air Engines
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) 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. 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. 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.
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. The compressed-air locos were soon withdrawn due to a number of accidents, possibly caused by icing in the pipes of the brakes, which were also worked by compressed air. Later achievements were by: The Hardie Compressed Air Locomotive, 1892-1900 The Hoadley-Knight Compressed Air Locomotive, 1896-1900 H. K. Porter Compound Air Locomotives, 1896-1930 The European Three-Stage Air Locomotive, 1912-1930 Terry Miller, air car advocate, 1979
Compressed Air Engine Basics A Compressed-air engine is a pneumatic actuator that creates
useful work by expanding 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.
Some types rely on pistons and cylinders, others use turbines.
Many compressed air engines improve the performance by heating the incoming air, or the engine itself. Some took this a stage further and burned the fuel in the cylinder or turbine, forming a type of internal combustion engine. 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. One manufacturer claims to have designed an engine that is 90% 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 called hybrid-pneumatic electric propulsion. Additionally, regenerative braking can also be used in conjunction with this system.
Fabrication of Parts and Assembly As per the design, following mechanical parts were used to fabricate the working model: Crank shaft 1 Pneumatic cylinder 2 Compressor Pneumatic pipe Body base Connecting screws
Description of Components of Compr essed Air Engine
Various Mechanical parts used in engine are: 1. Crank shaft 2. Connecting rod 3. Piston cylinder 4. Roller bearing 5. Pneumatic compressor
Crankshaft The crankshaft, sometimes usually abbreviated
to crank, is the part of an engine that 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. In transport engines, alloy steel e.g. Manganese steel having ultimate strength of about 784 to 940 MPa is generally used. Failure of crank shaft may occur at the position of m aximum bending; this may be at the center of the crank or at either end. Second, the crank may fail due to twisting, so the connecting rod needs to be checked for shear at the position of maximal twisting. The pressure at this position is the maximal pressure, but only a fraction of maximal pressure.
Connecting Rod
In a reciprocating piston engine, the
connecting rod or conrod connects the piston to the crank or crankshaft. Together with the crank, they form a simple mechanism that converts linear motion into rotating motion. The usual form of connecting rod used in engines has an eye at the small end for the piston pin bearing, a long shank, and a big end opening which is usually split to take the crankpin bearing shells. The connecting rods of internal combustion engine are mostly manufactured by drop forging. The connecting rod should have adequate strength and stiffness with minimum weight. The materials for connecting rod range from mild or medium carbon steel to alloy steels.
Piston Cylinder A cylinder is the central working part of a
reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminium or cast iron before receiving precision machine work. Cylinders may be sleeved (lined with a harder metal) or sleeveless (with a wear-resistant coating such as Nikasil). A piston is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder. In some engines, the piston also acts as a valve by
Roller Bearing
The concept behind a Bearing is very simple: Things roll better
than they slide. The wheels on your car are like big bearings. If you had something like skis instead of wheels, your car would be a lot more difficult to push down the road. That is because when things slide, the friction between them causes a force that tends to slow them down. But if the two surfaces can roll over each other, the friction is greatly reduced. Bearings reduce friction by providing smooth metal balls or rollers, and a smooth inner and outer metal surface for the balls to roll against. These balls or rollers "bear" the load, allowing the device to spin smoothly.
Compressor
A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. Compressors are similar to pumps: both 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, so the main action of a pump is to pressurize and transport liquids .Compressed air Piston range operates between 0.75 kW to 420 kW (1hp to 563 hp) producing working pressure at 1.5 bar to 414 bar (21 to 6004psi). Compressed air Vane compressors operate between 1.1 kW to 75 kW (1.5 to 100hp), producing working pressures of 7 to 8 and 10 bar (101 to 145psi).
VALVE TIMING DIAGRAM
Engine Compressed Air
Energy losses & Recovery
Much of the heat lost during the compression of the air can be regained from the operations of the car. The air in the compression-stage is extremely cold. The cold air can be reheated from the ambient atmosphere between each step to extract energy from it before being expanded through the next turbine
Applications of Air Engine
Tools Impact wrenches, drills, die grinders, dental drills and other pneumatic tools use a variety of air engines or
motors. These include vane type pumps, turbines and pistons. Torpedoes Most successful early forms of self propelled torpedoes used high pressure compressed air, although this was superseded by internal or external combustion engines, steam engines, or electric motors. Railways Compressed air engines were used in trams and shunters, and eventually found a successful niche in mining locomotives, although eventually they were replaced by electric trains, underground. Over the years designs increased in complexity, resulting in a triple expansion engine with air to air re-heaters
between each stage.
Aircraft
Transport category airplanes, such as commercial airliners, use compressed air starters to start the main engines. The air is supplied by the load compressor of the aircraft's auxiliary power unit, or by ground equipment. Automotive
Main article: Compressed air vehicle There is currently some interest in developing air cars. Several engines have been proposed for these, although none have demonstrated the performance and long life needed for personal transport
Emissions by IC Engines
Energy of Compressed Air If you compress air completely you actually get liquid. So we take
the energy value of liquid nitrogen (air consists of 70% nitrogen by volume) A way to calculate the energy value of 1 liter of compressed air: Energy Density/Specific Energy of liquid nitrogen = 320 KJ/L or 320,000 joules/liter Energy value of gasoline: 33,333 KJ/L or 33,000,000 joules/liter About 100 times more energy available in gasoline than in fully compressed air The transfer to mechanical power of compressed air is better than for gasoline
Production Costs Production cost of current marketable compressed-air car between $10,000-$15,000 Production cost of our compressed air car (with solar panels and magnesium car frame)between $15,000-$25,000
But remember, air compressed cars will benefit from gains in production such as:
Improved technology. Investment in research and development of compressed air cars will produce more efficient, cost-saving technologies such as discovery of cheaper materials (to replace limited quantities of current materials like magnesium), improved storage of compressed air, etc. Mass production
Economies of Scale
As the total number of vehicles produced increases, the fixed costs will remain the same while the varied costs will increase. This leads to a decreasing total average cost. Auto Industry benefits from economies of scale at tens of thousands and hundreds of thousands of vehicles produced.
Advantages 1. 2.
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Refueling can be done at home using an air compressor or at service stations. Reduced vehicle weight is the principal 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 pounds (360 kg) is a reasonable design goal. One manufacturer promises a range of 200 kilometers by the end of the year at a cost of €1.50 per fill-up. Compressed air engines reduce the initial cost of vehicle production by about 20%, because there is no need to build a cooling system, spark plugs, starter motor, or mufflers. Expansion of the compressed air lowers in temperature; this may be exploited for use as air conditioning. Compressed-air vehicles emit no pollutants. The technology is simple to achieve with low tech materials. This would mean that developing countries and rapidly growing countries like China and India, could easily implement the technology. The price of fueling air powered vehicles may be significantly cheaper than current fuels. Some estimates project $3.00 for the cost of electricity for filling a tank. Reduction or elimination of hazardous chemicals such as gasoline or battery acids/metals
Disadvantages 1. 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 compressed air cars, energy is lost when electrical energy is converted to compressed air. 2. When air expands in the engine, it cool significantly and must be heated to desired temperature using a heat exchanger. The cooling is necessary in order to obtain maximum efficiency. The heat exchanger, While it. Heats the stored air, the device gets very cold and may ice up in colder climates. 3. Refueling the storage tank of compressed air engine using a home or lowend 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. 4. 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.
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.
GALLERY Multiple views of the Yamaha YBX (4 stroke, 125cc) engine
The Complete engine
Side view of the engine showing Single Overhead Cam (SOHC
Engine Block after removal of upper cylinder head
Multiple views of Upper Cylinder Head
Cylinder Block
Engine Block after removal of upper cylinder head
Lower Engine Block
N
n
New Piston with rings
Cylinder block
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Camshaft in the head
Boring of Cylinder
Final Setup
References
Sharma P.C. & Aggarwal D.K., Machine Design, S.K. Kataria & Sons, E
d. 11th Reprint. Mahadevan & Reddy, Design Data Handbook, CBS Publishers, Ed. 3rd Mechanical Engineering and Design, TataMcGraw Hill, Ed. 3rd Wiki Foundation Wikipedia Website. How Stuff Works Website. Engineering Hobbyist Website.
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