Although the Euro-5 emissions standard is not due to come into force in the EU until 2008/2009, the Mercedes-Benz Bus and Coach Unit has already delivered the first seven Mercedes-Benz Citaro urban regular-service buses equipped with Euro 5-compliant OM 906 hLA horizontally-mounted turbodiesel engines developing 205 kW/279 hp. Winfried Heckt, Sales Manager Germany of the Mercedes Benz Bus and Coach Unit, handed over the vehicles to Markus Neumann, general manager of transport operator Verkehrsgesellschaft Breitenbach GmbH & Co. KG based in Hamm, Germany, in a ceremony held at the Mannheim bus and coach plant. At more or less the same time, the Dutch transport operator RET (Rotterdamse Elektrische Tram) took receipt of its first Euro-5 Citaro model �" part of a consignment totalling 90 Citaro urban buses which will be going into service in Rotterdam from August 2006.
From October 2006, diesel engines in Europe will have to comply with the Euro-4 emissions standard. The Citaro urban buses just delivered by the Mercedes-Benz Bus and Coach Unit are proof that Blue-Tec diesel technology based on SCR (Selective Catalytic Reduction), coupled with the installation of an SCR catalytic converter with an enlarged catalyst surface, already easily ensures compliance with the far more stringent Euro-5 emission standard.
"The OM 906 LA/hLA powerplant developing 205 kW is particularly suitable because it offers the ideal combination of highly efficient combustion and Blue-Tec technology," says Winfried Heckt, Sales Manager Germany of the Mercedes-Benz Bus and Coach Unit. There are two components at the heart of the new Blue-Tec diesel technology: enhanced engines and an integral exhaust-gas aftertreatment system. This system helps to ensure controlled conversion of the nitrogen oxides into harmless nitrogen and water vapour in an SCR catalytic converter, with the aqueous Ad-Blue solution being added as a reducing agent. Under the supervision of the engine management system, the required amount of Ad-Blue is drawn from a separate tank and injected into the hot exhaust stream where it is hydrolysed into ammonia and undergoes a chemical reaction.
To make the Mercedes-Benz Citaro urban buses Euro 5-compatible, the developers increased the size of the SCR catalytic converter and adjusted the Ad-Blue injection quantity. Consequently, the engine complies with the Euro-5 emissions standard which is due to come into force in 2009. Compared to Euro 4, Euro 5 stipulates a further 43 % reduction in the nitrogen oxide content of the exhaust gases.
Markus Neumann, general manager of Verkehrsgesellschaft Breitenbach GmbH & Co. KG, cites his reasons for purchasing the Mercedes-Benz Euro-5 vehicles now rather than later: "With the new Citaro, we want to send out a clear signal of intent. Environmental awareness is key when it comes to bus driving. As a transport operator, adopting this approach with our vehicles is an absolute must. We think it's truly fantastic that the option of Euro 5 is already available."
The new Mercedes-Benz Citaro regular-service buses with Euro-5 engines
All of the seven new Euro-5 vehicles ordered by Verkehrsgesellschaft Breitenbach GmbH & Co. KG and the 90 Euro-5 buses destined for RET are second-generation Mercedes-Benz Citaro models. These urban regular-service buses display a wealth of recently introduced technical and visual enhancements, the most eye-catching of which is undoubtedly the modified front section. The curved recess between the headlamps looks like a radiator grille and creates a visual link with the latest Mercedes-Benz touring coaches and rural-service buses. A continuous black moulding appears to draw the windscreen further downwards. Like the front-end flap, the corner panels, including the headlamp housings, can now be opened, making the entire front end ideally accessible for routine maintenance work and ensuring that the different sections are easy to replace in the event of accident damage. The rear end has also been modified and is now more three-dimensional in shape than that of the outgoing model. The imposing V-shaped rear window is drawn impressively upwards, stretching as far as the roof. Together, these design measures give the Citaro a more coherent and rounded form than conventional regular-service buses.
The vehicles are equipped with an electronic self-levelling suspension system that allows them to be lowered on one side (kneeling), making it easy for passengers to get on and off the bus. Additional folding ramps and externally-mounted request buttons located at a convenient height make it easier for people with restricted mobility, older passengers and parents with prams to use the buses. Moving inside the bus, the "sprayed-on" floor covering is extremely hard-wearing �" ideal if the bus is used on school runs. The destination indicators are 15-inch TFT screens which display the name of the next bus stop along with additional information for the passengers, such as timetable changes, and advertising. There is also an automatic bus-stop announcement system.
The new Euro-5 buses are fitted with disc brakes on all wheels as well as ABS and acceleration skid control (ASR). Further technical highlights of the Citaro include independent front suspension, featuring a design that is based on lower wishbones and a standard-fit stabiliser. In terms of handling and ride comfort, the benefits of independent wheel suspension and the resultant reduction in un-sprung masses can be clearly felt: straight-line stability is extremely impressive whilst there is less road impact on the steering. Furthermore, the turning circle is half a metre smaller than in the case of the first-generation Citaro. The Citaro buses are powered by the tried-and-trusted, horizontally mounted OM 906 hLA six-cylinder in-line engine with an output of 205 kW (279 hp) and a peak torque of 1120 Nm at 1300 rpm, while the transmission is a 4-speed automatic.
Verkehrsgesellschaft Breitenbach GmbH & Co. KG
The seven Mercedes-Benz Citaro regular-service buses with Euro-5 engines are painted white with a red/black front end and a distinctive blue interior. They will be used in urban areas (Hamm, Dortmund) and districts (Unna, Soest) as well as in the outer reaches of the Mark Brandenburg and Hochsauerland districts. Verkehrsgesellschaft Breitenbach GmbH & Co. KG has a total of 74 vehicles operating on these routes, all of which are low-floor buses equipped with traffic-light priority systems. Established in 1927, the company currently employs a workforce of 98 at its headquarters in Hamm, Germany.
90 new Euro-5 Citaro buses for RET in Rotterdam
Dutch local public transport operator PET from Rotterdam has invested more than € 20 million to replace practically half of its bus fleet with environmentally compatible Mercedes-Benz Citaro regular-service buses fitted with Euro-5 engines. This move makes RET the first local public transport operator in the Netherlands �" and one of the first in Europe �" to switch such a large percentage of its bus fleet over to Euro 5. In addition to the equipment already described, the second-generation Citaro vehicles also feature electrically extending wheelchair ramps, camera systems for monitoring the interior and digital bus-stop information and announcement systems.