Breaking cover for the first time today – the eCitaro makes its UK debut today at ITT Hub 2021 – as the ‘bus of the future is released in right-hand drive form.

Mercedes-Benz dealership EvoBus is using the two-day event at Farnborough to demonstrate the next generation of the well-regarded Citaro product.

Ahead of the show’s opening, journalists were invited to ‘ride & drive’ the new all-electric bus around the show’s specially designed circuit.

This proved the bus to be excellent to drive and use as a passenger. The bus was without any squeaks or rattles and the transmission was barely audible. Indeed, on a damp evening, the most noise was from the tyres, but that was not really noticeable.

Fitted with Mercedes-Benz’ attractive seats (with inset three-pointed logo) the interior can be configured to an operator’s requirements, while the power pack/drive train takes up the rear nearside corner. This is carried over from the left-hand drive version, which uses standard continental practice of an optional third rear door.

Fitted with large and clear conventional mirrors (digital mirrors – Mercedes-Benz’ MirrorCam system is an option), the bus drives exceptional well, our low-speed test drive revealed.

The steering is nicely balanced and precise, ensuring the driver has total confidence in it being ‘planted’ on the road. Acceleration is a brisk as you would ever need a passenger-carrying vehicle to be. Hill-hold – on a feircesome stiff slope – works excellently and we had no difficulty piloting the eCitaro around some tight turns.

Once the ITT Hub event closes, the bus will start a tour of the UK on pre-booked demonstration workings with a variety of UK operators, with the order book now open.

Standard high specification

Locally emission-free, quiet and highly efficient: the Mercedes-Benz eCitaro

It is locally emission-free and almost silent. It combines the tried-and-tested platform of the Mercedes-Benz city bus with new technological solutions. The fully electric Mercedes-Benz eCitaro brings electromobility for city buses to a whole new level. Impressively efficient in terms of energy usage, the performance of the eCitaro meets most of the requirements of the transport companies even at launch. Plus it is also already prepared for the battery technology of the future. Mercedes-Benz takes a holistic approach to electromobility and integrates the eCitaro into the overall eMobility system.

The eCitaro: world premiere in 2018, already a success

The eCitaro impresses with its performance and comes at precisely the right time. Although it was only presented to the world at the IAA for commercial vehicles in September 2018, it can now be seen on the roads of numerous cities. Further transport operators both in Germany and abroad are continually adding the bus to their fleets.

The tailor-made exclusive exterior of the eCitaro

The eCitaro benefits from the platform of the best-selling Citaro with more than 55,000 units sold all over the world. The eCitaro is a true Citaro – but a very special one because its unique characteristics match its equally unique design.

This is already evident in the face of the eCitaro. Its centre-point is formed by the Mercedes star. Decorative elements emanate from the star, to the left and right. The model insignia with its blue letter “e” discreetly and yet unmistakably indicates the fully electric drive technology. The bumper and the model-specific three-dimensional A0 pillars neatly frame the face of the eCitaro. Another feature of the city bus is the curve of its windscreen with the integrated destination display. Visually, the windscreen smoothly transitions into the roof with dark bars on the left and right.

The roof-mounted equipment on the eCitaro is concealed behind an elegant roof-edge ridge made of a multi-piece extruded aluminium section. The glossy black lower segment extends the generous side-window glazing of the city bus. The upper segment is painted in the vehicle colour. These design features lend the eCitaro perfect proportions.

Mercedes-Benz Citaro with full-electric drive system, 2 x electric hub motor, 2 x 125 kW, 2 x 485 Nm

A fusion of elegant and at the same time practical design

Overall, the eCitaro sports a solid appearance with clearly drawn contours and no showmanship whatsoever. At the same time, the eCitaro is a truly practical bus. The eCitaro adopts the exact structure of the current model – a crucial factor in facilitating the repair of accident damage, for example. The curved windscreen comes from the Citaro Ü and is thus a common spare part. The roof-edge ridge at the sides is not only a two-part design, it is also segmented.

Interior: coffered ceiling with high-tech lighting

In the passenger compartment, the eCitaro heralds a general update of the interior of the entire Citaro family. A stand-out feature in the interior is the coffered design ceiling above the centre aisle and the sweeping roof-edge flaps on the sides. They hide an air circulation system with textile ducts in place of the current plastic air ducts. They are even easier and simpler to install.

The technology modules as connectors between the individual elements of the coffered ceiling are particularly noteworthy. They combine the interior lights and the loudspeakers in one element. In line with this step, the interior lights have also been switched over to LED technology as standard. The lighting is ingenious: the light of the LED lamps is refracted in a way to make the technology modules appear to the observer as one homogeneous light panel.

Another impressive feature is the black trim on the sills and window posts. As a result, the window posts stand out less, soothing the appearance of the side walls.

Proven electric axle, now up to twelve battery modules

The powertrain of the new eCitaro is based on the proven and optimised ZF AVE 130 electric portal axle with electric motors at the wheel hubs. The peak output of the motors is 2 x 125 kW, while torque is 2 x 485 Nm. Downstream of the transmission this is 2 x 11,000 Nm at the wheel. An inherent feature of such systems, this torque is fully available right from the start, ensuring a high dynamic performance even with a full complement of passengers. Due to the high torque, acceleration is restricted to improve passenger comfort. This ensures that the eCitaro always exhibits the same dynamic but passenger-friendly behaviour when pulling away – both on the flat and on inclines.

Lithium-ion batteries supply the power. For the NMC1 batteries as supplied on this vehicle, the total capacity can reach 292 kWh. The batteries are split between up to twelve modules, each supplying 24.3 kWh. The basic equipment sees two battery modules on the vehicle roof plus four fitted at the rear. Depending on customer requirements, up to six further battery modules are mounted on the roof of the eCitaro. The maximum capacity with NMC2 batteries (12 pc on board) is 396 kWh or with solid-state batteries (7 pc) this reaches a maximum capacity of 441 kWh.

With the full complement of twelve batteries, the eCitaro presented here at the ITT HUB with standard equipment weighs 15.3 tonnes. With a permissible gross vehicle weight of 19.5 tonnes, this corresponds to a capacity for a one-door model of circa 70 passengers – very practical during rush hour.

Flexible charging technology: charging at the depot as standard, optional current collector

The eCitaro’s charging technology also allows it to adjust to the individual wishes and requirements of the transport operators. For series production, plug-in charging is envisaged. To this end, the city bus features a socket for a Combo 2 plug above the front wheel arch on the right-hand side of the vehicle in the direction of travel.

If intermediate charging is required to extend the range, there will in future also be an option to charge the eCitaro via a current collector on the roof. There are two possible variants: the eCitaro is optionally available with a current collector (pantograph) integrated into the roof and is also available with the other option of charging rails on the roof for charging with the stationary collectors of a charging station.

Thermal management: new methods for heating and air conditioning

However, the battery capacity alone provides little indication of the actual performance capability and, above all, the range of an all-electric city bus – the true measure is that of energy consumption. In the case of a city bus, this is impacted significantly by climatic conditions and the need to cool and, above all, to heat the interior.

At an outside temperature of minus ten degrees Celsius, the energy consumption of a city bus doubles compared to journeys where no heating is required. The engineers have therefore carefully considered the issue of thermal management. Compared with the current Citaro with combustion engine, the energy requirement for heating, ventilation and climate control has been reduced by about 40 percent. This exceptional energy efficiency provides the basis for the eCitaro’s practical operating range even under unfavourable conditions. This is accomplished with the use of innovative components that only reached market readiness in line with the eCitaro.

Heating featuring heat pump, networking of components

In the first instance, the batteries are heated or cooled to ensure that they remain at the ideal temperature, thereby ensuring maximum charging capacity, performance capability and service life. At extreme outside temperatures, the climate control system is used to boost the cooling of the batteries.

The passenger compartment of the eCitaro is heated in an energy-efficient manner by a heat pump. The familiar sidewall fan heaters are used to ensure even temperature distribution. The heater at the front is equipped with a double heat exchanger.

All components that give off heat are linked together, to keep the amount of energy required for their cooling to a minimum. Since the human body also gives off heat, the heating on a bus carrying a full complement of passengers can be turned down earlier. The output of the heating and air conditioning system varies depending on the vehicle’s load and the outside temperature.

The roof air conditioning is equipped with an additional heat pump function as standard. As a result we can heat the passenger compartment efficiently even at low outside temperatures. CO2 is used as the coolant. The heat pump is highly efficient because it uses the energy of the ambient air.

Another advantage: while the batteries are being charged in the depot, the vehicle interior can be pre-conditioned and even over-conditioned to the desired temperature. Thus energy necessary for the air conditioning is not taken from the battery which in turn increases range. In winter the bus can leave the depot over-conditioned, that is with a higher temperature, to counter cooling from outside which further reduces consumption when the bus is in operation. Accordingly, in summer the temperature can be reduced to lower levels.

Mercedes-Benz eCitaro: the test vehicle

The test vehicle in detail – maximum range, excellent passenger comfort, best possible functionality and an unrivalled standard of safety

The test vehicle demonstrates what the Mercedes-Benz eCitaro has to offer: maximum battery capacity, a comfortably equipped and welcoming passenger compartment, as well as an extremely functional driver cockpit. The test vehicle also boasts all the safety and assistance systems that are currently available, including Sideguard Assist and Preventive Brake Assist.

Batteries: full complement of twelve high-voltage battery assemblies

The test vehicle comes with a full complement of twelve high-voltage battery assemblies, which comprise an overall capacity of 292 kWh. The system-relevant range on 365 days of the year, even under difficult conditions, is around 150 km. The batteries are recharged at the depot using a plug located above the front axle wheel arch on the right-hand side of the vehicle.

eCitaro range on a single charge. *Range is dependent on vehicle load, speed, topography and weather

The eCitaro is networked, using the vehicle computer to send a multitude of data to the operator. It can also use the digital services of Omniplus On, such as Omniplus Uptime, for example. Omniplus Uptime constantly checks the status of the vehicle systems in real time. That includes all of the technology equipped with sensors, as well as the technology whose data can be called up in the CAN data bus system. Altogether, Omniplus Uptime monitors around 30 components and functions which, along with the drive, include doors, air conditioning system and level control.

The elegance of the quiet-running, locally emission-free and fully electric Mercedes‑Benz eCitaro is perfectly demonstrated by the test vehicle. Shimmering paintwork in smoke silver metallic, detachable parts included. The component covers on the roof are painted white, hidden behind the model-specific roof-edge ridge.

Passenger compartment: attractive equipment from the seating to the sockets

Three electric inward-swivelling doors with surround lighting open into the low-floor passenger compartment of the test vehicle. Passengers are greeted here with a colour scheme that boasts extraordinary style and efficiency in equal measure: graphite black flooring combined with passenger seat cushions and backrests in black-grey. The “City Star Eco” seats are from Mercedes-Benz. Powder-coated Evo Steel grab bars and sky-blue ceiling rails provide colour contrasts.

Passengers can charge their own portable electronic devices at 26 USB sockets. Information and entertainment is provided by the 29-inch screen behind the cross-aisle by the driver’s cab.

The middle door of the eCitaro additionally has a mechanically actuated folding ramp for passengers with impaired mobility. Space for a wheelchair or pram/buggy has been specially designated on the left of the vehicle in the direction of travel. Here, there is also a rearward-facing backrest with integrated folding seat. Two further folding seats can be found at the back of the specially designated area in the direction of travel.

During the changeover periods between hot and cold outside temperatures, the eCitaro enjoys fully automatic air conditioning as standard thanks to the highly efficient Evo Thermatic Plus system and also boasts a heater blower and air conditioner housing with double heat exchanger. Preconditioning at the depot reduces the energy consumption of the high-voltage batteries for heating and air conditioning, thus increasing the range of the city bus.

Driver’s area: functional and user-friendly

The driver’s cab is individually climatised, separated from the passenger compartment by a partition covering half the width of the rear door. The driver sits on a heated and climate-controlled seat. The cockpit is as accustomed, except that the rev counter is replaced by a power meter that displays the energy flow of the eCitaro. Drivers receive supplementary information as required via the central display between the speedometer and power meter.

The windscreen and side windows on the right and left, are electrically heated. The windows remain largely mist-free as a result, thus increasing active safety through better visibility. Additional control elements include a rain and light sensor, as well as an electrically adjustable inside rearview mirror for monitoring the passenger compartment.

Safety: all available safety systems on-board

The test vehicle is equipped with all the assistance and safety systems that are currently available. Including, for example, Sideguard Assist. Its radar sensors monitor the lane to the right of the vehicle throughout its full length and beyond. Sideguard Assist initially informs drivers when an obstacle has been detected in the warning zone. They then receive another warning should they initiate or continue with a manoeuvre when pulling away or driving that could lead to a collision. If a moving object is in the monitoring zone to the side of the vehicle, a yellow LED lamp lights up at the driver’s eye level in the A0 pillar on the right-hand side. If there is a risk of collision, the LED flashes brightly several times in red. It then remains permanently illuminated in red. There is also a haptic vibration in the driver’s seat.

Equally impressive is the active braking assistance system Preventive Brake Assist. The assistance system warns of collisions with moving pedestrians or stationary/moving objects and automatically initiates partial application of the brakes in the event of an immediate risk of collision. The series of warnings and the braking intervention are configured to the driving conditions expected in urban traffic. In the event of an imminent collision, Preventive Brake Assist alerts the driver both visually with an illuminated red triangle and vehicle icon in the central display, and audibly. The partial braking applied at the same time lasts until the driver intervenes or the bus comes to a halt.

The Electronic Stability Program ESP® is another eCitaro assistance system, which includes anti-slip control, braking assist (BAS), tyre pressure monitoring (TPM) and roll and pitch control. Despite the higher roof load, this prevents any unpleasant tilting on bends or severe pitching when braking.

The eCitaro also boasts an impressive portfolio of LED lighting technology: full LED headlamps, front fog lamps, cornering lights, daytime running lamps, clearance lamps and tracking lamps with LED technology. LED technology saves electricity, shines brightly and is designed with the service life of a bus in mind.

And should anything happen, despite all precautions taken: an outstanding safety feature in the front end of the city bus is the protection against frontal collisions. Combined with the reinforced components and a defined frame structure which steers impact forces directly to the substructure in a collision, the new Citaro even conforms to the requirements of the swing-bob impact test as specified in the European regulation ECE R 29.

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