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. 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 compressedair 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 called hybrid-pneumatic electric propulsion. Additionally, regenerative braking can also be used in conjunction with this system. 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. 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. 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. Applications: 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. Advantages: The advantages are well publicised 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. Reference: http://seminarprojects.com/Thread-design-and-fabrication-of-compressedair-engine#ixzz3UkBftn6X COMPRESSED AIR ENGINES.pdf (Size: 216.27 KB / Downloads: 638) Abstract A compressed air engine is primarily an engine that uses the energy stored compressed air to do work. Here the expansion of compressed air stored at high pressure in a storage tank occurs in the engine cylinder to move a piston doing mechanical work. The main application of this engine is in automobile industry where the potential energy of the compressed air is converted into kinetic energy of the linear motion of piston and rotary motion of the crank and the crank shaft. This motion is transferred to the wheels using usual transfer mechanisms .As the working fluid is compressed air there is no requirement of any other fuel other than some amount of electrical energy for compression of air in an electric compressor .The engine is free of emissions at the tailpipe as the only exhaust is air and is environmental friendly. Even though it is below its counterparts in power, comfort and performance, its supporters believe that altered versions of this engine are to dominate the automobile industry in future.
Introduction A Compressed-air engine is a pneumatic actuator that creates useful work by expanding compressed air and converting the potential energy into motion. A pneumatic actuator is a device that converts energy into motion The motion can be rotary or linear, depending on the type of actuator. CAE’s are fueled by compressed air, which is stored in a tank at high pressure such as 30 MPa. The difference between the compressed air engine and IC engine is that instead of mixing fuel with air and burning it to drive pistons with hot expanding gases, compressed air engine use the expansion of previously compressed air to drive their pistons. This technology has been used by many companies like MDI (Motor Development Industry) to develop cars and other vehicles running on compressed air engine. Parts A basic compressed air engine primarily consists of a source of air under high pressure, means for supplying air from source to engine cylinder, a cylinder system, and an exhaust system. There are also auxiliary parts like the heater which improves the power output and efficiency of the engine.The source is a storage tank where compressed air of pressures as high as 30Mpa is stored. The storage tank is likely to be made of carbon-fiber in order to reduce its weight while achieving the necessary strength. There is a cylinder having a reciprocating piston .There is also means to supply air from tank to cylinder to drive piston. A crank shaft is coupled to piston and is driven responsive to the reciprocating motion of piston, suitable mechanical arrangement coupled to crank shaft supply power to compressor, and also an independent means to supply power to compressor. Means for supplying air to cylinder comprises: a cylinder head, an auxiliary chamber in cylinder head,
conduit means for connecting tank to auxiliary chamber, and input valve operative to periodically admit air from auxiliary chamber into the chamber formed by cylinder head and the top of piston, the periodicity of admission of air being synchronized with the rotation of crank shaft. There is also an inlet valve to allow the entry of air from the surroundings .There are also carbon filters to eliminate dirt, dust, humidity, and other urban air impurities that could hamper the engine’s performance. There is an exhaust valve that lets the expanded air out. A lubricant compartment is provided below the engine cylinder that provides suitable lubrication for the engine. The basic parts of a compressed air engine are illustrated in the figure given below. Working The compressed air from the storage tank is supplied to the cylinder system by means of supply system. In the cylinder system the air first enters an auxiliary chamber from where it is periodically admitted to the main cylinder. The auxiliary chamber produces some power other than improving the overall efficiency of the engine. The compressed air which expands in the cylinder moves the piston down. When the piston moves up the exhaust valve opens and the expanded air is pushed out. In more evolved systems, the top portion of the main cylinder doubles up as the compressor. the linear up and down motion of the piston is converted to the rotary motion of the crank and crank shaft .This is transferred to the wheels by transfer mechanisms. Parked: It automatically shuts down the engine when the car is stationary. At Lower Speeds: Since the Compressed Air Vehicle is running exclusively on compressed air, it emits only air. The air expelled from the tail pipe is actually cleaner than the air used to fill the tank. This is because before compression, the air is run through carbon filters to eliminate dirt, dust, humidity, and other urban air
impurities that could hamper the engine’s performance. At Higher Speeds: At speeds over 35mph the Compressed Air Vehicle uses small amounts of fuel–either gasoline, propane, ethanol or bio fuels–to heat air inside a heating chamber as it enters the engine ( again, to expand volume before entering engine). This process produces emissions of only 0.141lbs of CO2 per mile. That is up to 4 times less than the average vehicle and more than two times less than the cleanest vehicle available today. The compressed air engine works in four different modes according to requirement Mode A: Operating with compressed air from Air Tank only in town less than 30 kph. In this mode, high pressure air from storage tank expands in the cylinder and moves the piston. The linear motion of piston is converted unto rotary motion of crank shaft. Mode B: Operating with compressed air from Air Tank only which is then heated by the heater to expand volume before entering engine. this increases the power output. Mode C: Operating with air from the Intake which is being heated to expand volume before entering engine. This is used on highway over 35 mph. Mode D: Operating as in Mode C but also refilling air Tank while running. Advantages The principal advantages of an air powered vehicle are: 1) Refueling can be done at home using an air compressor or at service stations. 2) 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.
3) One manufacturer promises a range of 200 kilometers by the end of the year at a cost of € 1.50 per fill-up. 4) 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. 5) Expansion of the compressed air lowers in temperature; this may be exploited for use as air conditioning. 6) Compressed-air vehicles emit no pollutants. 7) 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. 8) 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. 9) Reduction or elimination of hazardous chemicals such as gasoline or battery acids/metal 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 cools 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 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. 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. Uses 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. Conclusion With gas prices soaring, as they have over the past two years, it might not be long before many motorists turn to vehicles powered by alternative fuels. Although airpowered vehicles are still behind their gasoline
counterparts when it comes to power and performance, they cost less to operate and are arguably more environmentally friendly, which makes them attractive as the future of highway transportation. References Automobile technology by John Hawkins. Advanced air engine technology by Guy Negre. Air Engines by Franklin Newett New Age Technologies by Wivian Hurly Reference: http://seminarprojects.com/Thread-compressed-air-engine-14354#ixzz3UkBtY4sc
COMPRESSED AIR ENGINES.pdf (Size: 216.27 KB / Downloads: 638) Abstract A compressed air engine is primarily an engine that uses the energy stored compressed air to do work. Here the expansion of compressed air stored at high pressure in a storage tank occurs in the engine cylinder to move a piston doing mechanical work. The main application of this engine is in automobile industry where the potential energy of the compressed air is converted into kinetic energy of the linear motion of piston and rotary motion of the crank and the crank shaft. This motion is transferred to the wheels using usual transfer mechanisms .As the working fluid is compressed air there is no requirement of any other fuel other than some amount of electrical energy for compression of air in an electric compressor .The engine is free of emissions at the tailpipe as the only exhaust is air and is environmental friendly. Even though it is below its counterparts in power, comfort and performance, its supporters believe that altered versions of this engine are to dominate the automobile industry in future.
Introduction A Compressed-air engine is a pneumatic actuator that creates useful work by expanding
compressed air and converting the potential energy into motion. A pneumatic actuator is a device that converts energy into motion The motion can be rotary or linear, depending on the type of actuator. CAE’s are fueled by compressed air, which is stored in a tank at high pressure such as 30 MPa. The difference between the compressed air engine and IC engine is that instead of mixing fuel with air and burning it to drive pistons with hot expanding gases, compressed air engine use the expansion of previously compressed air to drive their pistons. This technology has been used by many companies like MDI (Motor Development Industry) to develop cars and other vehicles running on compressed air engine. Parts A basic compressed air engine primarily consists of a source of air under high pressure, means for supplying air from source to engine cylinder, a cylinder system, and an exhaust system. There are also auxiliary parts like the heater which improves the power output and efficiency of the engine.The source is a storage tank where compressed air of pressures as high as 30Mpa is stored. The storage tank is likely to be made of carbon-fiber in order to reduce its weight while achieving the necessary strength. There is a cylinder having a reciprocating piston .There is also means to supply air from tank to cylinder to drive piston. A crank shaft is coupled to piston and is driven responsive to the reciprocating motion of piston, suitable mechanical arrangement coupled to crank shaft supply power to compressor, and also an independent means to supply power to compressor. Means for supplying air to cylinder comprises: a cylinder head, an auxiliary chamber in cylinder head, conduit means for connecting tank to auxiliary chamber, and input valve operative to periodically admit air from auxiliary chamber into the chamber formed by cylinder head and the top of piston, the periodicity of admission of air being synchronized
with the rotation of crank shaft. There is also an inlet valve to allow the entry of air from the surroundings .There are also carbon filters to eliminate dirt, dust, humidity, and other urban air impurities that could hamper the engine’s performance. There is an exhaust valve that lets the expanded air out. A lubricant compartment is provided below the engine cylinder that provides suitable lubrication for the engine. The basic parts of a compressed air engine are illustrated in the figure given below. Working The compressed air from the storage tank is supplied to the cylinder system by means of supply system. In the cylinder system the air first enters an auxiliary chamber from where it is periodically admitted to the main cylinder. The auxiliary chamber produces some power other than improving the overall efficiency of the engine. The compressed air which expands in the cylinder moves the piston down. When the piston moves up the exhaust valve opens and the expanded air is pushed out. In more evolved systems, the top portion of the main cylinder doubles up as the compressor. the linear up and down motion of the piston is converted to the rotary motion of the crank and crank shaft .This is transferred to the wheels by transfer mechanisms. Parked: It automatically shuts down the engine when the car is stationary. At Lower Speeds: Since the Compressed Air Vehicle is running exclusively on compressed air, it emits only air. The air expelled from the tail pipe is actually cleaner than the air used to fill the tank. This is because before compression, the air is run through carbon filters to eliminate dirt, dust, humidity, and other urban air impurities that could hamper the engine’s performance. At Higher Speeds: At speeds over 35mph the Compressed Air Vehicle uses small amounts of fuel–either gasoline, propane, ethanol or bio
fuels–to heat air inside a heating chamber as it enters the engine ( again, to expand volume before entering engine). This process produces emissions of only 0.141lbs of CO2 per mile. That is up to 4 times less than the average vehicle and more than two times less than the cleanest vehicle available today. The compressed air engine works in four different modes according to requirement Mode A: Operating with compressed air from Air Tank only in town less than 30 kph. In this mode, high pressure air from storage tank expands in the cylinder and moves the piston. The linear motion of piston is converted unto rotary motion of crank shaft. Mode B: Operating with compressed air from Air Tank only which is then heated by the heater to expand volume before entering engine. this increases the power output. Mode C: Operating with air from the Intake which is being heated to expand volume before entering engine. This is used on highway over 35 mph. Mode D: Operating as in Mode C but also refilling air Tank while running. Advantages The principal advantages of an air powered vehicle are: 1) Refueling can be done at home using an air compressor or at service stations. 2) 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. 3) One manufacturer promises a range of 200 kilometers by the end of the year at a cost of € 1.50 per fill-up. 4) 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. 5) Expansion of the compressed air lowers in temperature; this may be exploited for use as air conditioning. 6) Compressed-air vehicles emit no pollutants. 7) 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. 8) 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. 9) Reduction or elimination of hazardous chemicals such as gasoline or battery acids/metal 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 cools 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 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. 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. Uses 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. Conclusion With gas prices soaring, as they have over the past two years, it might not be long before many motorists turn to vehicles powered by alternative fuels. Although airpowered vehicles are still behind their gasoline counterparts when it comes to power and performance, they cost less to operate and are arguably more environmentally friendly, which makes them attractive as the future of highway transportation. References
Automobile technology by John Hawkins. Advanced air engine technology by Guy Negre. Air Engines by Franklin Newett New Age Technologies by Wivian Hurly Reference: http://seminarprojects.com/Thread-compressed-air-engine-14354#ixzz3UkBtY4sc
