Tata OneCAT
The Tata OneCat is announced in 2008 the prototype of a compressed air car, which was developed in cooperation by Tata Motors in India and the air motor developer Guy Nègre of MDI. In the U.S., a purchase price 5100-7800 U.S. $ is expected.
The cooperation has been suspended since 2009 because, according to Tata " insurmountable problems " technical nature occurred. Both Tata and MDI in public relations was adjusted to this prototype since that date.
Technology
The OneCat is a five-seater small car with a trunk volume of 200 liters. According to the manufacturer's instructions with full tanks OneCat has a range of 90 km at a speed of 100 km / h In addition, an internal combustion engine are used, which is to increase the range to 800 km (at a fuel consumption of 1.5 liters per 100 km). The car includes the manufacturer air tanks that can be filled by an integrated car compressor that plugs into a standard wall outlet, in four hours. MDI is even planning a compressor for filling stations that can fill the tank in three minutes.
Although the technical concept of the compressed air car works, no reference and no prototype has so far been presented, the low - consumption reached values - specified by the manufacturer.
Objections from physico- technical perspective
The drive of a vehicle with the aid of compressed air has a number of technical problems:
- The ratio of made available to drive energy and weight is unfavorable in the compressed air tanks, compared, for example, already with simple lead-acid batteries.
- Compressed air is very inefficient in the production of the most expensive and energy. When formed in the heat of compression can not be used, it is lost for the energy balance.
- An efficient compressed air motor must as far as possible to relax in the isothermal limit. Therefore he needs a multi-stage relaxation with intermediate heating and is therefore expensive ( engine design ). The space required for this is difficult providable in a mobile vehicle. (According to his own statement of MDI leaves the relaxed air of the "exhaust " with -40 degrees C. This confirms that the engine is operated far from the isothermal border, but almost certainly very close to the adiabatic limit. This means a maximum theoretical yield of the energy contained in the compressed air storage of 50%. )
- By expansion of the compressed air, there is a cooling of the engine. It has to be supplied from the ambient heat. If this is not sufficient to ensure the performance of the expander motor decreases. At low ambient temperatures, the efficiency of the motor is in any case even further reduced.