Air powered car

Wednesday, 31 October 2012

Air powered car

compressed-Air car

concept air car

A compressed-air vehicle (CAV) 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 use the expansion of compressed air to drive their pistons. One manufacturer claims to have designed an engine that is 90 percent efficient.

A compressed air car is a car that uses a motor powered by compressed air. The car can be powered solely by air, or combined (as in a hybrid electric vehicle) with gasoline, diesel, ethanol, electricity

History

Compressed air has been used since the 19th century to power mine locomotives and trams in cities such as Paris (via a central, city-level, compressed air energy distribution system), and was previously the basis of naval torpedo propulsion.
During the construction of the Gotthardbahn from 1872 to 1882, pneumatic locomotives were used in the construction of the Gotthard Rail Tunnel and other tunnels of the Gotthardbahn.
In 1903, the Liquid Air Company located in London England manufactured a number of compressed-air and liquified-air cars. The major problem with these cars and all compressed-air cars is the lack of torque produced by the "engines" and the cost of compressing the air.
Recently several companies have started to develop compressed air cars, although none have been released to the public, or have been tested by third parties.

Air engine

A pneumatic motor or compressed air engine
It is a type of motor which does mechanical work by expanding compressed air. Pneumatic motors generally convert the compressed air to mechanical work through either linear or rotary motion. Linear motion can come from either a diaphragm or piston actuator, while rotary motion is supplied by either a vane type air motor or piston air motor.
Pneumatic motors have existed in many forms over the past two centuries, ranging in size from hand held turbines to engines of up to several hundred horsepower. 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. Pneumatic motors have found widespread success in the hand-held tool industry and continual attempts are being made to expand their use to the transportation industry. However, pneumatic motors must overcome inefficiencies before being seen as a viable option in the transportation industry.

Compressed air cars are powered by motors driven by compressed air, which is stored in a tank at high pressure such as 30 MPa (4500 psi or 310 bar). Rather than driving engine pistons with an ignited fuel-air mixture, compressed air cars use the expansion of compressed air, in a similar manner to the expansion of steam in a steam engine.
There have been prototype cars since the 1920s, with compressed air used in torpedo propulsion

Air storage tank

The tanks must be designed to safety standards appropriate for a pressure vessel, such as ISO 11439.
The storage tank may be made of:
steel,
aluminium,
carbon fiber,
Kevlar,
other materials, or combinations of the above.
The fiber materials are considerably lighter than metals but generally more expensive. Metal tanks can withstand a large number of pressure cycles, but must be checked for corrosion periodically

Advantages

The principal advantages of an air powered vehicle are:
*Refueling can be done at home using an air compressor or at service stations. The energy required for compressing air is produced at large centralized plants, making it less costly and more effective to manage carbon emissions than from individual vehicles.

*Compressed air engines reduce the cost of vehicle production, because there is no need to build a cooling system, spark plugs, starter motor, or mufflers.

*The rate of self-discharge is very low opposed to batteries that deplete their charge slowly over time. Therefore, the vehicle may be left unused for longer periods of time than electric cars.

*Expansion of the compressed air lowers its temperature; this may be exploited for use as air conditioning.

*Reduction or elimination of hazardous chemicals such as gasoline or battery acids/metals

*Some mechanical configurations may allow energy recovery during braking by compressing and storing air.

*Sweden’s Lund University reports that buses could see an improvement in fuel efficiency of up to 60 percent using an air-hybrid system But this only refers to hybrid air concepts (due to recuperation of energy during braking), not compressed.

Disadvantages

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 conventional combustion motor cars, the energy is lost when chemical energy in fossil fuels is converted to mechanical energy, most of which goes to waste as lost heat. For compressed-air cars, energy is lost when chemical energy is converted to electrical energy, when electrical energy is converted to compressed air, and then when the compressed air is converted into mechanical energy.

*When air expands in the engine it cools dramatically and must be heated to ambient temperature using a heat exchanger. The heating is necessary in order to obtain a significant fraction of the theoretical energy output. The heat exchanger can be problematic: while it performs a similar task to an intercooler for an internal combustion engine, the temperature difference between the incoming air and the working gas is smaller. In heating the stored air, the device gets very cold and may ice up in cool, moist climates.

*This also leads to the necessity of completely dehydrating the compressed air. If any humidity subsists in the compressed air, the engine will stop due to inner icing. Removing the humidity completely requires even additional energy that cannot be reused and is lost.

*Conversely, when air is compressed to fill the tank it heats up. If the stored air is not cooled as the tank is filled, then when the air cools off later, its pressure decreases and available energy decreases. The tank may require an internal heat-exchanger in order to cool the air quickly and efficiently while charging, since without this it may either take a long time to fill the tank, or less energy is stored.
*Refueling the compressed air container using a home or low-end conventional air compressor may take as long as 4 hours, though specialized equipment at service stations may fill the tanks in only 3 minutes.To store 14.3 kWh @300 bar in 300 liter reservoirs (90 m3 of air @ 1 bar), requires about 30 kWh of compressor energy (with a single-stage adiabatic compressor), or approx. 21 kWh with an industrial standard multistage unit. That means a compressor power of 360 kW is needed to fill the reservoirs in 5 minutes from a single stage unit, or 250 kW for a multistage one.However, intercooling and isothermal compression is far more efficient and more practical than adiabatic compression, if sufficiently large heat exchangers are fitted. Efficiencies of up to 65% may be achieved,[8] however this is lower than the Coulomb's efficiency with lead acid batteries.

*The overall efficiency of a vehicle using compressed air energy storage, using the above refueling figures, is around 5-7%.[citation needed] For comparison, well to wheel efficiency of a conventional internal-combustion drivetrain is about 14%,

*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.

*A 2005 study demonstrated that cars running on lithium-ion batteries out-perform both compressed air and fuel cell vehicles more than threefold at the same speeds. MDI claimed in 2007 that an air car will be able to travel 140 km in urban driving, and have a range of 80 km with a top speed of 110 km/h (68 mph) on highways,when operating on compressed air alone, but in as late as mid 2011, MDI has still not produced any proof to that effect.

*A 2009 University of Berkeley Research Letter found that "Even under highly optimistic assumptions the compressed-air car is significantly less efficient than a battery electric vehicle and produces more greenhouse gas emissions than a conventional gas-powered car with a coal intensive power mix." However, they also suggested, "a pneumatic–combustion hybrid is technologically feasible, inexpensive and could eventually compete with hybrid electric vehicles."

engineers are trying to invent a way of compressing the natural air by means of a compresser in car itself if they succeed car itself prepares its own fuel so no need of filling tanks the tank is always full

Crash safety

Safety claims for light weight vehicle air tanks in severe collisions have not been verified. North American crash testing has not yet been conducted, and skeptics question the ability of an ultralight vehicle assembled with adhesives to produce acceptable crash safety results. Shiva Vencat, vice president of MDI and CEO of Zero Pollution Motors, claims the vehicle would pass crash testing and meet U.S. safety standards. He insists that the millions of dollars invested in the AirCar would not be in vain. To date, there has never been a lightweight, 100-plus mpg car which passed North American crash testing. Technological advances may soon make this possible, but the AirCar has yet to prove itself, and collision safety questions remain.

The key to achieving an acceptable range with an air car is reducing the power required to drive the car, so far as is practical. This pushes the design towards minimizing weight.

According to a report by the U.S. Government's National Highway Traffic Safety Administration, among 10 different classes of passenger vehicles, "very small cars" have the highest fatality rate per mile driven. For instance, a person driving 12,000 miles per year for 55 years would have a 1% chance of being involved in a fatal accident. This is twice the fatality rate of the safest vehicle class, a "large car". According to the data in this report, the number of fatal crashes per mile is only weakly correlated with the vehicle weight, having a correlation coefficient of just (-0.45). A stronger correlation is seen with the vehicle size within its class; for example, "large" cars, pickups and SUVs, have lower fatality rates than "small" cars, pickups and SUVs. This is the case in 7 of the 10 classes, with the exception of mid-size vehicles, where minivans and mid-size cars are among the safest classes, while mid-size SUVs are the second most fatal after very small cars. Even though heavier vehicles sometimes are statistically safer, it is not necessarily the extra weight that causes them to be safer. The NHTSA report states: "Heavier vehicles have historically done a better job cushioning their occupants in crashes. Their longer hoods and extra space in the occupant compartment provide an opportunity for a more gradual deceleration of the vehicle, and of the occupant within the vehicle... While it is conceivable that light vehicles could be built with similarly long hoods and mild deceleration pulses, it would probably require major changes in materials and design and/or taking weight out of their engines, accessories, etc."

Air cars may use low rolling resistance tires, which typically offer less grip than normal tires.In addition, the weight (and price) of safety systems such as airbags, ABS and ESC may discourage manufacturers from including them.

Tata Motors

As of January 2009 Tata Motors of India had planned to launch a car with an MDI compressed air engine in 2011.In December 2009 Tata's vice president of engineering systems confirmed that the limited range and low engine temperatures were causing problems.Tata Motors announced in May 2012 that they have assessed the design passing phase 1, the "proof of the technical concept" towards full production for the Indian market. Tata has moved onto phase 2, "completing detailed development of the compressed air engine into specific vehicle and stationary applications".

conclusion

Air powered car can solve our fuel
problems in future but it takes some time to fully develop a perfect model of it we have many other technologies coming and rapidly developing now like high efficient petrol powered engines of ford the Ford eco boost engines which gives high fuel efficiency and many other tech but air fuel is the ultimate source of fuel because it has 0 emissions just air so lets hope the day comes soon when our cars could also live on air