Compressed air car

from Wikipedia, the free encyclopedia
The Tata OneCAT is a prototype of a compressed air car

A airpod (engl .: compressed air car ) is a motor vehicle , with the aid of compressed air and a pneumatic motor is driven. The compressed air is carried in pressure tanks and fed to the engine.

It is therefore an emission-free vehicle in accordance with the Californian emissions standards with alternative drive technology .

Compressed air cars for public road traffic have been presented again and again since the 1990s under the umbrella term of alternative vehicle technology; series production has not yet taken place. The Indian vehicle manufacturer Tata Motors wants to introduce a series-ready car together with MDI (Motor Development International) in 2020.

Compressed air drive in general

Stationary air motors can be found in many different machines and tools.

Various niche applications with compressed air drive, such as trams in Bern and compressed air-powered locomotives , e.g. B. in the construction of the Gotthard tunnel or mine locomotives, were realized in the past. Many of these special areas of application have now been replaced by electric drive systems that are simpler and also emission-free.

Industrial steam storage locomotives have a similar concept and technology.

history

As early as 1838 Adraud and Tessié du Motay designed a compressed air car in Paris and presented it in 1840. In rail transport, this type of drive was first used in 1879 on the tram in Nantes (France). The systems were developed by the French engineer of Polish descent Louis Mékarski .

For the Paris-Rouen 1894 race , six vehicles from France with compressed air drive were registered, but none appeared at the start:

Participant / manufacturer origin Places
Berthaud (start number 78) Lyon 8th
A. Duchemin (start number 38) Paris 4th
Plantard (start number 84) Paris 4th
Victor Popp (start number 9) Paris 4th
Roze-Andrillon (start number 95) Marseille 4th
Société Parisienne (start number 52) Paris 4th

The US manufacturers MacKenzie & McArthur in New Haven ( Connecticut ) and the Autocrat Manufacturing Company in Hartford (Connecticut) dealt with the compressed air vehicle. An automobile powered by compressed air was to bear the name American Pneumatic , the planning of which was announced by the American Vehicle Company in February 1900 . Pneumatic vehicles from the brands Automatic Air , Carrol , Meyers , Muir and Pneumatic were also not marketed . According to the early US American trade journal The Hub , the United States Vehicle Company was founded in 1899 in Delaware with a massive share capital of US $ 25 million for the purpose of "developing the inventions of Stackpole and Francesco and manufacturing mid-range automobiles with compressed air drive" . The company is mentioned in the book Horseless Vehicles, Automobiles and Motorcycles by Hiscox at 1129 Broadway in 1900 and can be found on the New York City Register at 52 Broadway as late as 1911 . What was ultimately achieved with this enormous capital investment is unclear.

properties

The compressed air drive works without any combustion processes and without the risk of sparking, as is the case with electrical systems. It can therefore be used very well in explosive environments, such as B. in mining underground.

On the other hand, there are restrictions that speak against its use as a means of mass transport. Large (heavy) compressed air tanks are necessary to carry a sufficient amount of drive energy. The energy density of the drive system is already unfavorable in comparison with simple lead-acid batteries .

Compressed air is one of the most expensive sources of energy. In terms of energy, their generation is subject to very large losses. If the heat generated during compression cannot be used, it is lost for the energy balance. An efficient compressed air motor requires a multi-stage expansion with intermediate heating and is therefore complex (motor concept). The motor cools down by releasing the compressed air. Heat must be supplied from the environment. If this is not sufficiently guaranteed, the performance of the expansion motor will decrease. This effect is intensified at low ambient temperatures.

The developments of Nègre

With his company MDI from France , the French Formula 1 engine designer Guy Nègre began to develop a special air motor for vehicle propulsion in the early 1990s. These efforts led to the Tata OneCAT concept vehicle .

Press releases have repeatedly announced the planned start of production and sales since 1995, and for years series production has been announced for the next year. Work is continuing on the development in cooperation with the Indian vehicle manufacturer Tata-Motors . A new type of production concept has been announced in Europe, whereby the vehicles will be produced directly at the dealership.

Guy Nègre was nominated in 2002 for the Eurosolar Prize for Alternative Transport Systems. However, the nomination was withdrawn after questions about the operating experience of the prototypes could not be answered. The stated mileage could not be independently checked so far. A crash test has not yet taken place in practice either.

The developer cites low maintenance costs and a long service life as advantages. The functioning of the engine developed by Nègre does not differ fundamentally from the well-known principle of a gas expansion engine: compressed air expands in two cylinders, the pistons of which drive the car. The engines of the vehicles, which weigh only 500 to 700 kilograms, should have an output of 30 hp (22 kW). Edible oil is used as a lubricant.

For a full tank, 90,000 liters of air (around 110 kilograms) are compressed to a pressure of 300 bar and stored in four compressed air cylinders with a total volume of 300 liters, coated with Kevlar . According to the manufacturer, the charging process takes about four to six hours at a 230-volt socket, and two minutes at a corresponding compressor station.

According to the manufacturer, only costs for electrical energy, wear parts , lubricants and taxes are incurred for operation, only 20 kWh are required for a tank filling (depending on the electricity tariff, about 3 to 6 euros). In the past, the manufacturer spoke of a range of 240 km at a constant 60 km / h, at a top speed of 110 km / h 100 kilometers should be possible. In order to enable longer ranges, there should be models with an internal combustion engine that generates additional compressed air. The manufacturer currently specifies a range of around 70 kilometers. Experts considered these values ​​to be far too optimistic. There is no independent reference for the manufacturer's information.

Other models

At the Geneva Motor Show 2009, MDI presented two new models, AirPod and OneFlowAir .

The AirPod is a four-seater just over two meters long and 220 kg curb weight. According to the specification, the front chassis consists of a vertical single-axis control with wheelbarrow wheels in double design (also known as "furniture castor control"), with the size 10 × 4.00-5 (excerpt from the published technical data: "Train avant: Diabolo deux roues, Pneumatiques Avant: 10 × 4.00-5 »).

The OneFlowAir is a 3.40 m long and up to five-seater convertible, which is similar in shape to the Citroën Méhari . In addition to the compressed air drive , the OneFlowAir should contain an internal combustion engine to extend the range.

In 2013 there were also developments to use compressed air for hybrid drives in motor vehicles.

criticism

In a study by the University of California, Berkeley , a comparison was made between gasoline cars, battery electric cars and compressed air cars in terms of greenhouse gas emissions , fuel costs, primary energy consumption and tank volume in relation to the US state of California. A conventional Smart Fortwo , a battery-electric Smart Fortwo ED and a hypothetical compressed air car served as comparison objects . The technical parameters of the compressed air vehicle, if unknown, were estimated optimistically. In terms of greenhouse gas emissions, fuel costs and tank volume, the compressed air car performed significantly worse for California than the gasoline or battery-powered car. Only in the point of primary energy consumption was there an advantage over the petrol car, but only when using renewable energy. According to the Californian study, the battery-powered car performed significantly better than the compressed air car in all respects. The sustainability of primary energy storage and its technology was not taken into account here, although air and gasoline can be used in fuel tanks, so current battery technology is based on lithium. Lithium is extremely problematic for the environment both in production and in subsequent disposal and has not been correctly assessed. Battery technology could prevail if alternatives to gases (Research Hamburg), dry cells or more environmentally friendly and frequently occurring substances (nickel-zinc, potassium-air or chromium-iron) can be used efficiently as a battery. In particular, however, the breakthrough in cathode technology (California, USA) could soon make the harmful cobalt in lithium-ion batteries superfluous and replace it with “disordered rock salts”. The study by Berkeley University in California is therefore not incorrect in the results of the factors tested, but important points of comparison have simply not been included.

Further criticism of MDI is currently being leveled by current and former business partners, mainly with regard to promised services and technology transfers that have never been carried out.

See also

Commons : Pneumatic Auto  - Collection of Pictures, Videos and Audio Files

Individual evidence

  1. ↑ Tata Airpod air-powered car likely to be launched by 2020. In: International Business Times, India Edition. February 17, 2017, accessed March 18, 2018 .
  2. ^ Compressed-Air Propulsion. In: douglas-self.com. May 10, 2013, accessed May 16, 2016 .
  3. ↑ Tessié du Motay Andraud: About the compressed air as a universal driving force and free substitute for steam power. German from CH Schmidt. Voigt, Weimar 1841.
  4. ↑ Pneumatic tram (English).
  5. ↑ Le Petit Journal. July 22, 1894.
  6. ^ Kimes: Standard Catalog. 1985, p. 875.
  7. ^ Kimes: Standard Catalog. 1985, p. 81.
  8. ^ Kimes: Standard Catalog. 1985, p. 929.
  9. ^ Kimes: Standard Catalog. 1985, p. 967.
  10. ^ Kimes: Standard Catalog. 1985, p. 1173.
  11. ^ Kimes: Standard Catalog. 1996, p. 1489.
  12. ↑ Luftikus: MDI presents AirPod and OneFlowAir. heise Autos, March 20, 2009, accessed on March 22, 2009 (with picture gallery).
  13. ↑ www.mdi.lu .
  14. ↑ "A hydraulic pump on the gearbox builds up pressure when the car decelerates. The stored energy is sufficient to bring the car back up to speed with a hydraulic motor after a stop at traffic lights." Drive from the compressed air cylinder
  15. ^ Economic and environmental evaluation of compressed-air cars. November 17, 2009, accessed January 1, 2010 .
  16. ↑ News. ( Memento from January 15, 2010 in the Internet Archive ) at: catecar.ch

literature

  • Beverly Rae Kimes (Editor), Henry Austin Clark, Jr.; The Standard Catalog of American Cars. 2nd Edition. Krause Publications, Iola WI, USA 1985, ISBN 0-87341-111-0 , pp. 42, 81, 875, 929, 967, 1173, 1542.

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