Tata OneCAT

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Tata / MDI OneCAT

The Tata OneCat is an advertised in 2008 prototype airpod , which in cooperation with Tata Motors in India and the air motor developer Guy Nègre of MDI was developed. In the US, a purchase price of US $ 5100 to 7800 is expected.

The collaboration has been suspended since 2009 because, according to Tata, "insurmountable problems" of a technical nature occurred. Both Tata and MDI have ceased public relations work on this prototype since then.

technology

The OneCAT is a five-seater small car with a trunk volume of 200 liters. According to the manufacturer, the OneCAT has a range of 90 km at a speed of 100 km / h with full tanks. In addition, an internal combustion engine should be used, which should increase the range to 800 km (with a fuel consumption of 1.5 liters per 100 km). According to the manufacturer, the car contains air tanks that can be filled in four hours by a compressor integrated in the car, which is plugged into a standard socket. MDI is even planning a compressor for gas stations that can fill the tanks in three minutes.

Although the technical concept of the compressed air car works, no reference or prototype has been presented that could achieve the low consumption values ​​specified by the manufacturer.

Objections from a physical-technical point of view

Driving a vehicle with the help of compressed air presents a number of technical difficulties:

  • The ratio of the drive energy made available to the weight is unfavorable in the case of compressed air tanks, compared, for example, with simple lead-acid batteries .
  • Compressed air is very inefficient to produce and one of the most expensive energy carriers. If the heat generated during compression cannot be used, it is lost for the energy balance.
  • An efficient air motor must relax as much as possible at the isothermal limit. To do this, it requires multi-stage relaxation with intermediate heating and is therefore complex (engine concept). The installation space required for this is difficult to provide in a mobile vehicle. (According to MDI's own statement, the relaxed air leaves the "exhaust" at -40 ° C. This confirms that the engine is operated far from the isothermal limit, but almost certainly very close to the adiabatic limit maximum theoretical yield of the energy contained in the compressed air reservoirs of 50%.)
  • 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. At low ambient temperatures, the already moderate efficiency of the motor is reduced even further.

Web links

Individual evidence

  1. ↑ Hamilton, Tyler: Technology Review: The Air Car Preps for Market
  2. ↑ Harrabin, Roger: An engineer has promised that within a year he will start selling a car that runs on compressed air, producing no emissions at all in town , BBC News, February 13, 2008