Main article: Compressed air energy

An air engine or air motor is a device for converting potential energy from compressed air into kinetic energy to drive other machines. As in a steam engine, expansion of externally supplied pressurized gas performs work against one or more pistons or rotors to move wheels or other tools. Image File history File links Sustainable_development. ... Main article: compressed air Compressed Air Energy Storage (CAES) refers to the compression of air to be used later as energy source. ... For other uses, see Engine (disambiguation). ... A motor is a device that converts energy into mechanical power, and is often synonymous with engine. ... Potential energy can be thought of as energy stored within a physical system. ... Pneumatics is the use of pressurized air to effect mechanical motion. ... The cars of a roller coaster reach their maximum kinetic energy when at the bottom of their path. ... This article is about devices that perform tasks. ... // The term steam engine may also refer to an entire railroad steam locomotive. ... For the American composer, see Walter Piston. ... R0t0r is from efnet ... For other uses, see Wheel (disambiguation). ...

A compressed air vehicle can offer many of the advantages of a battery electric vehicle without the need for heavy and potentially toxic batteries, which take hours to recharge instead of the few minutes required to refill the tanks for an air engine. Like an electric vehicle, a compressed air vehicle will usually be pollution free during operation. However the energy required for compression must be sourced, and will usually be derived from electricity, or an internal combustion engine. Depending on the method used to generate the electricity, the energy may contribute significant quantities of greenhouse gases and other pollutants, especially if fossil fuels are used. Although some air engines may be highly efficient, the system efficiency, including compression of the air, heat rejection, electricity losses and electricity generation, may be less than 25%. For electric vehicles other than battery powered passenger automobiles, see electric vehicle. ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... Fossil fuels or mineral fuels are fossil source fuels, this is, hydrocarbons found within the top layer of the earth’s crust. ... Transmission towers Transmission lines in Lund, Sweden Electric power transmission, or more accurately Electrical energy transmission, is the second process in the delivery of electricity to consumers. ... The thermal efficiency () is a dimensionless performance measure of a thermal device such as an internal combustion engine, a boiler, or a furnace, for example. ...

History

The air engine and its idea of using air as an energy carrier is not new. Air has been used since the 19th century to power mine locomotives, and has been the basis of naval torpedo propulsion since 1866. This article is about mineral extractions. ... Great Western Railway No. ... The torpedo, historically called a locomotive torpedo, is a self-propelled explosive projectile weapon, launched above or below the water surface, propelled underwater toward a target, and designed to detonate on contact or in proximity to a target. ...

Compressed air is still currently used in racecars to provide the initial energy needed to start the car's main power plant, the internal combustion engine (ICE). Auto racing (also known as automobile racing or autosport) is a sport involving racing automobiles. ... A colorized automobile engine The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ...

The most recent development uses pressurized air as fuel in an engine invented by Guy Nègre, a Formula One French engineer. In 1991, Guy Nègre started MDI, and invented a dual-energy engine, capable of running on both compressed air and 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, pushing the engine to above a comparable ICE-engine. The MDI MiniCAT‎ Moteur Developpement International (French: Motor Development International) is a Luxembourgian company that is famous for designing Compressed Air Engine vehicle prototypes marketed under the title the Air car. In 2002, a team of Swedish journalists from magazine Teknikens värld went to Nice to meet Guy N... F1 redirects here. ... Wikipedia does not have an article with this exact name. ...

Other people that have been working on the idea of compressed air vehicles, among them Uruguayan engineer Armando Regusci, Australian Angelo Di Pietro, Tony Salvino, South Korea Chul-Seung Cho, and more recently, Kernelys' K'Airmobiles compressed air vehicles. They too have companies, Regusci's RegusciAir, Di Pietro's EngineAir [1] and Chul-Seung Cho's Energine, selling their engines. Tony Salvino, however is a high school student who is pursuing a more efficient engine. This article or section is in need of attention from an expert on the subject. ... Angelo Di Pietro, ( born 1950, Avellino, Italy) qualified as Congegniatore Meccanico in Avellino moved to Stuttgart, Germany to work on the Wankel rotary engine at the Mercedes Benz research laboratories 1969 and 1970. ... This article or section is in need of attention from an expert on the subject. ... For other uses, see Air car (disambiguation). ...

Also since 2007, K'Airmobiles looks at commercialing some urban and leisure VPPs (Vehicles with Pneumatic Propulsion) and tries to gain partnerships and sponsors. Their goals appears to be individual transport and taxi-bikes as the projects proposed on the site are mainly made of a motor-bike and trikes (with 1 to 3 seats). A relaxing afternoon of leisure: a young girl resting in a pool. ...

In 2008 Tata Motors plan on producing the low-cost €3,500 MDI OneCAT that is powered by an air engine.^[1] Tata Motors Limited, formerly known as TELCO (TATA Engineering and Locomotive Company), is Indias largest passenger automobile and commercial vehicle manufacturing company. ... The euro (€; ISO 4217 code EUR) is the currency of twelve European Union member states: Austria, Belgium, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Portugal, and Spain. ...

Laws of physics

By Boyle's law it is known that Boyles law (sometimes referred to as the Boyle-Mariotte law) is one of the gas laws and basis of derivation for the ideal gas law, which describes the relationship between the product pressure and volume within a closed system as constant when temperature remains at a fixed measure; both...

For a fixed mass of ideal gas at fixed temperature, the product of pressure and volume is a constant. The formula is P1V1=P2V2 making pressure and volume indirectly related

Therefore under identical temperature:

• the pressure multiplied by the volume of a gas contained in a tank corresponds to a constant;
• the variation of pressure of the gas is inversely proportional to its volume.

If either the pressure or the volume are altered, the factor T can be modified accordingly. It is what brings to the concepts of thermodynamic, of adiabatic expansion of compressed air. Thermodynamics (Greek: thermos = heat and dynamic = change) is the physics of energy, heat, work, entropy and the spontaneity of processes. ... This article covers adiabatic processes in thermodynamics. ... Compressed air is used to refer to: Pneumatics, the use of pressurized gases to do work, as used in the Air car Breathing gas, often used in scuba diving, also to inflate buoyancy devices Compressed air can also be used for cooling using a vortex tube. ...

More the change of the pressure/volume ratio is fast and brutal, the less time the gas gets to satisfy this change and reflects part of the conversion to its temperature factor.

This is why the methods of use of compressed air in a system explain why, with compressed-air engines, two main trends exist, conceptually rather different:

Thermodynamic exploitation

In the event of fast expansion of a great quantity of compressed air, corresponding to an important lowering of pressure, the gas cannot physically find its entire original volume; a variation in temperature thus follows, namely meaning an important cooling, while the expansion of useful volume may be limited to approximately 40% of the theoretical volume only. Contrarily, with compression, the voluminal reduction generally involves a rise in temperature resulting once again in a total volume of compressed air lower than its theoretical value.

The technologies exploited by MDI, Energine and Quasiturbine (see hereunder) requiring relatively important flows when exploited to animate powerful engines, must thus obligatorily take account of these thermodynamic constraints.

Dynamic exploitation

To produce a mechanical push while circumventing this obstacle, or at least while reducing its effects, it is thus necessary to comply with certain rules:

• to allow expansion as slowly as possible, i.e. while working with low flows (but this, of course, results in a reduction in engine power).
• to regulate the abrupt variations of pressure (by the use of pressure reducers and other intermediate decompression rooms),
• to maintain as much as possible a constant gas temperature, which reduces energy losses during compression/expansion by a cooling/heating of the air.

Engine design

It uses the expansion of compressed air to drive the pistons of the engine, to propulse the vehicle or generate electricity. 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. Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ...

The source for air is a pressurized carbon-fiber tank holding air at around 20 MPa (3,000 psi, 200 bar). 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. Graphite-reinforced plastic or carbon fiber reinforced plastic (CFRP or CRP), is a strong, light and very expensive composite material or fibre reinforced plastic. ... MPA is a TLA (three-letter acronym) that may mean: Macedonian Press Agency Marine Protected Area Maritime Patrol Aircraft Maryland and Pennsylvania Railroad (AAR reporting mark MPA) Master of Public Administration Master of Public Affairs Max Planck Institute for Astrophysics Metropolitan Police Authority Mid-atlantic Pagan Alliance Motion Picture Association... The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. ... An injection system is a system delivering fuel to an internal combustion engine. ...

Armando Regusci's version of the air engine has several advantages over the original Nègre design. In the original Nègre 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. Nègre's 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 some efficiency. In Regusci's version, the transmission system is direct to the wheel, and has variable torque from zero to the maximum, enhancing efficiency. When vehicle is stopped, Guy Nègre's engine has to be on and working, losing energy, while the Regusci's version need not.

In July 2004, Guy Nègre abandoned his original design, and showed later a new design that he stated to have invented in year 2001, but his new design is identical to the Armando Regusci's air engine which was patented back in 1989 (Uruguay) with the patent number 22976, and back in 1990 (Argentina). In those same patents, it is mentioned the use of electrical motors to compress air in the tanks.

Besides the compressed air engine designs by Regusci, Nègre, and EngineAir, the Quasiturbine is also capable of running on compressed air, and is thus also a compressed air engine. The Quasiturbine or Qurbine engine is a proposed pistonless rotary engine using a four-sided rhomboid rotor whose sides are hinged at the vertices. ...

Disadvantages

Having solved most of the high pressure storage and handling problems, the main remaining disadvantages are related to the thermodynamics. Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dynamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ...

• At the supply station, compressing the air heats it, and if then directly transferred in a heated state to the vehicle storage tanks will then cool and reduce the pressure. If cooled before transfer, the energy in this heat will be lost unless sophisticated low grade heat utilization is employed (see cogeneration).
• Within the vehicle, expansion and consequent pressure reduction in the throttle or engine chills the air, reducing its effective pressure. Addition of ambient heat will increase this pressure and this addition leads to a more complex propulsion system. While an attempt was made in the Nègre system to warm the air in a long portion of the stroke at top dead center, it appears that this scheme has been abandoned due to inherent imbalances causing unacceptable levels of vibration.
• Passenger compartment heating is more difficult since the propulsion system does not provide a source of waste heat. Some form of heat pump, or more likely, an electric heater would be required.
• Limited range due to available tank technology. The air engine suffers from similar problems to hydrogen vehicles in this regard.
• Using energy to compressed air is less efficient than charging a battery with that same energy.
• Less efficient than electric motors.
• While the air engine reduces greenhouse gas emissions from the vehicle, the energy used to compress the air may not come from clean sources.
• Long refill times when compared to conventional automobiles (4 Hours).^[2]

Not to be confused with California Highway Patrol. ... A heat pump is a machine or device that moves heat from one location (the source) to another location (the sink), using work. ... Sequel, a fuel cell-powered vehicle from General Motors Hydrogen vehicle refers to a personal transportation vehicle, such as an automobile, that uses hydrogen as its on-board fuel for motive power, but can also refer to other vehicles, such as an aircraft, that use hydrogen in a similar fashion. ...

Advantages

The principle advantages for an air powered vehicle are:

• Fast recharge time, 3 or 4 minutes for volume transfer.
• Very low self-discharge rate (most batteries will deplete their charge without external load at a rate determined by the chemistry, design, and size, while compressed gas storage will have an extremely low leakage rate)
• Long storage lifetime device (electric vehicle batteries have a limited useful number of cycles, and sometimes a limited calendar lifetime, irrespective of use). This means that batteries in operation are much more expensive than compressed air storage, and are more pollutant because a lot more pollutant material needs to be used (typical car batteries are made from sulphuric acids and lead).
• Lower initial cost than battery electric vehicles when mass produced (€3,000).
• Expansion of the compressed air reduces its temperature and heat from the passenger compartment may be cooled using a heat exchanger, providing both relief from hot weather air conditioning and increased efficiency.
• Zero pollutant emissions from the vehicle itself.

Self-discharge is a phenomenon in batteries in which internal chemical reactions reduce the stored charge of the battery without any connection between the electrodes. ... Lifetime can refer to: Life expectancy, the length of time a person is alive One of the American media ventures owned by Lifetime Entertainment Services Lifetime (TV network), a cable television network Lifetime Movie Network, a cable movie network Lifetime (band), an American melodic hardcore punk band from New Jersey... Main article: compressed air Compressed Air Energy Storage (CAES) refers to the compression of air to be used later as energy source. ... Mass production is the production of large amounts of standardised products on production lines. ... A heat exchanger is a device built for efficient heat transfer from one fluid to another, whether the fluids are separated by a solid wall so that they never mix, or the fluids are directly contacted. ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ...

Uses of air engine

Further information: compressed air vehicle and compressed air storage

The air engine is an emission-free piston engine using compressed air as fuel that was invented by Guy Nègre, a French engineer. ... Main article: compressed air Compressed Air Energy Storage (CAES) refers to the compression of air to be used later as energy source. ...

Road vehicles

The Nègre CityCAT engine is used to power an urban car with room for five passengers and a projected range of about 160 to 320 km (100 to 200 miles)^{[citation needed]}, depending on traffic conditions. The main advantages are: no roadside emissions, low cost technology, engine uses food oil for lubrication (just about 1 liter, changes only every 50,000 km (30,000 miles) ) and integrated air conditioning. Range could be quickly tripled^{[citation needed]}, since there are already carbon fiber tanks which have passed safety standards holding gas at 70 MPa (10,000 lbf/in²) . An urban car is a car designed to be used in city traffic. ... The litre or liter (see spelling differences) is a unit of volume. ...

The tanks may be refilled in about three minutes at a service station^{[citation needed]} (using volume transfer), or in a few hours at home or in parking lots plugging the car into the electric grid via an on-board compressor. The cost of driving such car is projected around €0.75 per 100 km, with a complete refill at the "tank-station" at about US$3. This article does not cite any references or sources. ... Look up grid in Wiktionary, the free dictionary. ... Look up compressor, compression in Wiktionary, the free dictionary. ...

Cars

Air engines can be used in Cars. This article or section does not cite its references or sources. ...

Ships

They can be used as outboard motors. Bolinders two cylinder Trim outboard engine. ...

Powered model vehicles

Main article: Powered model car

Small single cylinder engines are also incorporated into toy flying airplane models and car models. Metal die-cast model of a Ferrari 365 GTB/4 Highly detailed die-cast model of a Porsche Carrera GT by Minichamps A model car is a miniature representation, or scale model, of an automobile or similar powered vehicle, generally reproducing the shapes of actually-produced vehicles. ...

Compressed air as an energy carrier

Energy density and efficiency

Main article: compressed air storage

Ideal air compression and expansion is described by the isothermal process. Compressing air however heats it up and expanding it cools it down. Therefore practical air engines require heat exchangers in order to avoid excessively high or low temperatures and even so don't reach ideal constant temperature conditions. Nevertheless it is useful to describe the maximum energy storable using the isothermal case, which works out to about 110 kJ/Nm3 at 24°Celsius. A Nm3 is a cubic meter of gas volume at normal, i.e. atmospheric pressure, conditions. Thus if 1.0 m3 of ambient air is very slowly compressed into a 5-liter bottle at 200 bar, the potential energy stored is 583 kJ (or 0.16 kWh). A highly efficient air motor could transfer this into kinetic energy if it runs very slowly and manages to expand the air from its initial 200 bar pressure completely down to 1 bar (bottle completely "empty" at ambient pressure). This is practically impossible and if the bottle is emptied down to 10 bar, the energy extractable is about 330 kJ. The efficiency of isothermal compressed gas storage is theoretically 100% but in practice the process is not isothermal and the two engines (compressor and motor) have various losses. Main article: compressed air Compressed Air Energy Storage (CAES) refers to the compression of air to be used later as energy source. ... An isothermal process is a thermodynamic process in which the temperature of the system stays constant: ΔT = 0. ...

A standard 200 bar 5 liter steel bottle has a mass of 7.5 kg, a superior one 5 kg. Bottles reinforced with or built from high-tensile fibers can be below 2 kg in this size, always regarding legal safety codes. Thus we get energy densities from roughly 75 up to 300 kJ/kg. Ordinary steel bottles thus have about the same energy density as lead-acid batteries and advanced fiber-reinforced bottles that of superior electrochemical storage batteries. However, modern batteries provide almost their full energy at a nearly constant voltage, whereas the pressure of compressed air storage varies greatly. It is technologically difficult for air engines to maintain high efficiency and sufficient power values over such pressure swings.

The advantage of compressed air over electric storage is the longer lifetime of pressure vessels compared to batteries and the lower toxicity of the materials used. However for this to count, air engines must become as light, efficient and cheap as available electric motors. Compressed air tanks can also be charged more safely than those with inflammable fuels. For example, grocery or hypermarket store parking spaces could be fitted with pressure hoses or electric grid, thus not requiring large central stations. This article does not cite any references or sources. ... Plastic hoses. ...

As with electric technology, it must be stressed that compressed air is only an energy vector therefore can only be as clean as its source. However, even as an energy carrier it will still provide adequate and cleaner power even by compare to petroleum based fuels, like gasoline or diesel.

Safety

As with most technologies, compressed air has safety concerns, mainly the catastrophic rupture of the tank. Rigid safety codes make this a rare occurrence at the cost of weight: codes may require the working pressure to less than 40% of the rupture pressure for steel bottles and less than 20% for fiber-wound bottles. High pressure bottles are fairly strong so that they stay unruptured in crashes and follows the ISO 11439 standard.

Technical boundaries

For practical application to transportation, several technical problems must be first addressed:

• As the pressurised air expands, it is cooled, which limits the efficiency (see combined gas law). 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 pressurize 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 fiber 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 necessarily emission-free, since the power to compress the air initially may produce emissions at the point of generation. However such emissions from the power to compress the air initially would be far less than the emissions from gasoline powered cars and trucks already on the streets based on petroleum.

The ideal gas law or equation is the equation of state of an ideal gas. ... Carbon fiber composite is a strong, light and very expensive material. ... Petro redirects here. ...

See also

• Alternative fuel
• Alternative propulsion
• Battery electric vehicle
• Compressed air torpedo
• Compressed air storage
• Compressed air vehicle
• Glider
• Liquid nitrogen economy
• Pneumatics
• Quasiturbine
• Zero-emissions vehicle

The definition of alternative fuel varies according to the context of its usage. ... Alternative propulsion is a term used frequently for power train concepts differing to the standard internal combustion engine concept used in gasoline- or diesel-fueled vehicles. ... For electric vehicles other than battery powered passenger automobiles, see electric vehicle. ... The torpedo, historically called a locomotive torpedo, is a self-propelled explosive projectile weapon, launched above or below the water surface, propelled underwater toward a target, and designed to detonate on contact or in proximity to a target. ... Main article: compressed air Compressed Air Energy Storage (CAES) refers to the compression of air to be used later as energy source. ... The air engine is an emission-free piston engine using compressed air as fuel that was invented by Guy Nègre, a French engineer. ... For other uses, see Glider (disambiguation). ... A liquid nitrogen (LN2) economy is a hypothetical proposal for a future economy in which the primary form of energy storage and transport is liquid nitrogen. ... Pneumatics is the use of pressurized air to effect mechanical motion. ... The Quasiturbine or Qurbine engine is a proposed pistonless rotary engine using a four-sided rhomboid rotor whose sides are hinged at the vertices. ... General Motors EV1 A zero-emissions vehicle, or ZEV will produce no emissions or pollution from the vehicle when stationary or operating. ...

External links

Air-Powered Cars at HowStuffWorks HowStuffWorks is a website created by Marshall Brain but now owned by the Convex Group. ...

• How to convert hook up your air engine to the chassis (originally for electric engines)
• Movie of Discovery Channel's Science Channel on the air car
• Times Of India Article- "Air-fulled car catches Tata's gust of wind"
• RegusciAir Club Company site
• Pneumatic Options (general resource with history, photos, comprehensive external links)
• Air engines used to power mine locomotives, and might today be used again to power locomotives - compressed air locomotives-
• Air engine applications