In the meantime the Citaro even got a little brother, the Cito. Introduced at the International Commercial Vehicle Show in Hanover in 1998, it surprised the public with a tailor-made midibus concept: alternatively eight, nine or ten meters length and 45 to 65 seats were the key specifications. The Cito had unusual design features: One was a self-supporting aluminum frame with a roof and floor made of aluminum and walls made of plastic. Another was a diesel-electric drive, combined into a compact power pack extending to the roof at the rear of the bus. The Cito impressed people with new solutions and, technically, was far ahead of its time. Perhaps even too far ahead. At any rate, the market responded coolly to the innovative bus. Five years after launching the Cito Mercedes-Benz withdrew it again.

Mercedes-Benz Cito

The conventional drive system of the Citaro was more successful. The diesel engines of the Citaro comprised two different series, all six-cylinder in-line engines. The displacement was 6.4 and twelve liters. Outputs ranged from 185 kW (252 hp) and 1100 Nm torque to 260 kW (354 hp) and 1600 Nm. Both engine series are identical in design except for a few adapters. Fuel was injected by the pump-line-nozzle system, which permits high injection pressures and is economical in operation as a result. A fully electronic engine management system further cut consumption. With this technology, the Citaro profited from the development of the Mercedes-Benz Actros heavy-duty truck presented one year earlier, the first vehicle to show such technology.

The diesel engines of the Mercedes-Benz Citaro optionally could be combined with a CRT system (combination of oxidation catalyst and particulate filter). Automatic transmissions from ZF and Voith were available.

Today, diesel engines whose exhaust gases are treated by the SCR (Selective Catalytic Reduction) system are used to comply with the Euro 4 und Euro 5 emission standards. This technology further cuts pollutant emissions substantially, while on the other hand creating prerequisites for possibly reducing fuel consumption still more.

Natural gas engine on request

Optionally, the Citaro also can be had with a natural gas-fired engine which meets the Euro 4 standard. The OM 447 hLAG is available with outputs of 185 kW (252 hp) and 240 kW (326 hp) and with optional EEV certification. This variant even does distinctly better than required by the Euro 5 standard that takes effect in 2008/2009. Together with low noise emissions and the eco-friendly manufacturing methods of the Mannheim factory, this created the prerequisites for awarding the “Blue Angel” symbol for environmentally friendly products to the natural gas-powered buses of Regionalbus GmbH in Mühlhausen, Thuringia.

Low-emission drive systems: Citaro - Naturalgas drive system.