Mr Vorgerd, what is the importance of the Mercedes-Benz eCitaro G for electromobility in city buses?

Because of their high passenger capacity, articulated buses are above all used on high-frequency routes in cities and metropolitan areas. Such areas are particularly environmentally sensitive. This refers both to noise and exhaust emissions. The eCitaro G not only offers plenty of room, it is also locally emissions-free and quiet. In this way, it presents an important step along the path towards electromobility and a better quality of urban life.

Why did the eCitaro G first take to the streets long after the rigid version?

One big point was the simultaneous première of next-generation battery technology. Because with a permissible total weight of 30 instead of 19 tonnes and a much larger passenger compartment, an articulated bus clearly needs more energy to achieve the same range as its rigid peers. Here, every extra kilowatt-hour on board helps. And we also had to temporally coordinate the comprehensive safeguarding programmes of the rigid and articulated buses.

Why does the eCitaro G with two drive axles exist?

A fully occupied eCitaro G still weighs 30 tonnes. On lines with traffic lights and stops at a hard incline, the two powered axles offer outstanding drive dynamics. In addition, on icy roads in winter, these two drive axles give a marked benefit to traction and road safety. And also: with our concept of two motors close to the wheel hubs of each axle, this solution is comparatively easy to implement.

We often talk of the modularity of the eCitaro G –what does this mean in practice?

The eCitaro G is a tailor-made city bus. This above all refers to the batteries: we offer it with the option of NMC or solid-state batteries. Both battery technologies can be obtained in various configurations. Also, our customers can choose, where NMC battery charging technology is concerned, between plug, pantograph or charging rail. And last but not least, the plugs can come at three different positions: as standard, right above the front wheel, but also left and in the rear. Up to two positions can be fitted per vehicle. This means maximum flexibility at the depot.

One challenge was the weight distribution between the axles of articulated buses. How did you approach this challenge?

By putting the batteries of the articulated bus in a different position to the rigid bus. In the articulated bus, where the motor and transmission would have been in a rigid bus, we fit two instead of four battery packages. This places much less of a burden on the rear axle. We put the other battery packages on the roof at the front of the rear section and on the roof of the front section. The very sturdy eight-tonne front axle is identical. This creates a perfect weight distribution and allows the maximum number of seats.

Articulated buses need more energy than their rigid cousins. How do you nevertheless achieve maximum range?

Like in a rigid bus, we have implemented comprehensive thermal management to optimise energy consumption. This includes the networking of all heat-producing components. In addition, heating is carried out by a highly efficient heat pump using CO2 as a medium. Already during charging at the depot, the compartment is conditioned – it can even be somewhat over-conditioned. This means that in winter the articulated bus leaves the depot a little hotter and in summer a little cooler than necessary. In this way, we stretch out every last kilometre of range. Heating and air-conditioning are also fully automated and are based on the occupancy of the passenger compartment.

What do the drivers need to adapt to when switching from a diesel to an electric articulated bus?

Changing from a traditional bus to an eCitaro G is completely unproblematic. “Climb aboard and get going” is our motto – so the driver’s cockpit is as close as possible to the diesel-driven Citaro. Only the rev counter has been replaced by a power meter. It shows the energy demanded and the recuperation. This helps the driver to be energy-efficient.

The eCitaro G is clean – but how safe is it?

We treat safety as the most important principle. Our roll and pitch control, fitted as standard, prevents uncomfortable sideways inclinations despite the heavy batteries on the roof. With the Articulation Turntable Controller (ATC), also fitted as standard, we achieve drive stability approximately on the level of an ESP. Particularly valued by transport companies and drivers are the optional assistance systems – Preventive Brake Assist, Active Brake Assist and the turning aid, Sideguard Assist. This takes some of the burden off the driver and effectively protects more vulnerable road users such as pedestrians and cyclists.