Tunisia
Natural gas vehicles are continuing to make inroads into Africa, with Iveco Irisbus delivering two compressed natural gas (CNG) CityClass buses to the city of Tunis in Tunisia. The delivery is part of a cooperation agreement between the Italian Ministry of Foreign Affairs and the Tunisian Ministry of Transport that covers (reaches) a total of more than 100 vehicles for Tunis.
The units demonstrate how CNG technology can help transport to improve air quality, reduce the dependence on oil, improve fuel consumption and to improve passenger comfort. The CityClass CNG bus is an ultra-low emission vehicle which complies with the very strict E.E.V. exhaust emission level standard and improves the typical diesel noise emission level in more than 5 dB.
CityClass CNG units have a rigid configuration and a length of 12 m, and are equipped with the Iveco CNG dedicated engine Cursor 8 with a maximum power rating of 200 kW at 2000 r/min and a maximum torque of 1100 Nm from 1100 to 1700 r/min.
This engine, like all Iveco natural gas engines, complies with E.E.V (Environmentally Enhanced Vehicle) levels for the emission of exhaust pollution giving much lower values than those demanded from the standard, for example: in accordance with the European standard 2005/55/EC, it emits 0.53 g/kWh of NOx while the E.E.V. limit for this pollutant is situated at 2 g/kWh. (Current Euro 4 limit for NOx is 3.5 g/kW-h).
The Cursor 8 CNG is a gas engine, Otto cycle, with 6 cylinders, 24 valves, overhead camshaft, cutting-edge technology, ultra low exhaust emissions, with a stoichiometric combustion system and multi-point electronic injection with 12 gas injectors situated in a two by two format at the entrance to the inlet duct of each cylinder achieving an identical mixture in each of them.
As is standard in Iveco engines, the engine has a lambda probe in the exhaust as part of the close loop combustion control system which guarantees the stoichiometric combustion which isn’t affected by the composition of natural gas which reaches the cylinders.
The exhaust has a three-way catalyst, made of platinum and palladium to reduce the concentration of pollutants CO, HC and NOx produced by the combustion.
Current Iveco Irisbus bus CNG range includes rigid and artic buses with lengths from 9 to 18 m.
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