SEAT has introduced the new SEAT Mii Ecofuel, the lowest-emitting production car ever for the brand. This is part of plans to expand the Mii family. The Mii Ecofuel uses compressed natural gas (CNG), offering excellent efficiency and considerably lessened running costs without compromising the fun driving dynamics that the Mii is known for.
The Mii Ecofuel is the first model with a CNG engine to use a SEAT badge. This model was launched at the 2013 Geneva Motor Show. It has an average consumption of only 2.9 kg CNG/100 km.
Since the fuel price over this distance is less than 3 Euros (about £2.60) in many countries), the running costs are about half those of a Mii that uses a petrol engine. The 1.0-litre, 68 PS engine is based on the three-cylinder petrol unit fitted in Mii (with 60 PS and 75 PS outputs). However, it was designed particularly for CNG operation.
It emits only 79 g/km of CO2, its best-in-class. James Muir, President of SEAT S.A., said that the new SEAT Mii Ecofuel makes environmentally friendly CNG technology affordable for everyone. He also said that its attractive starting price and outstanding low consumption and emissions figures turn the Mii Ecofuel into a highly exciting and sensible choice.
This is true even for high-mileage drivers. The new SEAT Mii Ecofuel has an entry price of €12,050 in Germany and is the cheapest CNG model on the market. It’s expected for SEAL vehicles to offer amazing value-for-money and low maintenance costs.
Dr. Matthias Rabe, Vice President of Research and Development for SEAT, said that the Mii Ecofuel has the added benefits of “fun, functionality, efficiency and resource conservation without any compromise.” Because of the advanced vehicle architecture, the company was able to position the two CNG tanks under the vehicle floor to save room. As a result, the high functionality, safety and driving fun of the SEAT Mii are not affected.
The new SEAT Mii's CNG engine is technically very the same as the petrol engines and is also the made from aluminium. The 3-cylinder engine was modified in several areas in order to achieve optimal CNG operation.
Moreover, the compression ratio increased from 10.5:1 to 11.5:1, improving the combustion efficiency in the CNG operation. And the higher pressures, as well as the combustion chamber temperatures, have caused the spark plugs to have higher ignition voltage now. What's more, the gaseous fuels' lower lubrication characteristics are being compensated by different valves, special guides, as well as valve seats. The engine control unit and cam profiles have also been modified.
Additionally, in the new Mii Ecofuel, the ECU manages the gas injector valves as well as electronic gas pressure regulator. Also, the engine control unit utilizes a lambda sensor in order to recognize the various qualities of 'high gas' and 'low gas,' as they're sold, particularly on the German market. When the car is running low on gas, with a lower calorific value because of its lower methane content, it adapts injection timing to suit.
Furthermore, compared with conventional petrol, CNG combustion produces about a quarter less carbon dioxide, and significantly less hydrocarbons and carbon-monoxide. Soot or fine particulates are not emitted, although the catalyst has to convert unburnt residual methane. Because of this, slightly different precious metals are in the catalytic converter.