A green light for the Mercedes-Benz eCitaro

Softly humming, the new Mercedes-Benz eCitaro rolls into the gigantic Hall 45 in Mainz for its first official presentation to the public. The project team has transformed the rustic industrial architecture of the hall into an impressive showcase for the event. Almost 200 journalists from 15 countries are covering the presentation.

It’s time for the world premiere of the electric city bus from Mercedes-Benz.

I’ve been working on electric mobility for buses for the past three years, and as a prospective industrial engineer I wrote my thesis about this subject.

My choice of this topic was not random: I did a work-study program at Daimler, and during my last assignment at Daimler Buses I was involved with the EDB project. EDB stands for Electric Drive Bus, the fully electrified Mercedes-Benz eCitaro city bus, which is celebrating its world premiere today, July 10, in Mainz

Fascination city bus from the beginning

I’ve been fascinated by buses ever since I was a boy. During my schooldays I supplemented my pocket money by working in a bus repair shop operated by a transportation company that was based in my home town. Since 2015 I’ve been working in the Product Planning and Product Management department, where I’m responsible for alternative drive systems. My focus is on supporting the EDB project.

When the result of the entire EDB project team’s years of work is revealed to the public, it is an impressive presentation that really gives me goosebumps. Today, Martin Daum (Head of Daimler Trucks & Buses) and Till Oberwörder (Head of Daimler Buses) will also present the innovations that will be introduced at the IAA Commercial Vehicles at the end of September.

After that, our Head of Development, Gustav Tuschen, will present the highlights of the new eCitaro. The speakers will be supported by a gigantic 17-meter-wide projection wall that’s almost as long as an articulated bus. It will be an impressive sight for the guests, because it will make it possible to show many details of the new eCitaro.

Our demand: The best or nothing

The path to this new model was a challenging one. It’s true that the Citaro is the undisputed Number One among city buses, but some of our competitors launched the first electrically driven vehicles more quickly on the market. Both the general public and the policymakers are urgently calling for electric buses today. But electric buses are still suffering from serious start-up difficulties.

However, the team’s effort has obviously been successful, because even before the world premiere in Mainz we received from Hamburg the biggest single order ever placed for electric buses in Germany. Hamburger Hochbahn AG ordered 20 eCitaro buses.

A clear picture is emerging:

We’re not the fastest company, but our customers trust us and believe that we’re the best. I’m absolutely convinced that we will prove that when our buses are actually being driven by customers.

My product planning and product management team is the interface between development and sales. We have to reconcile the demands of bus companies with what is technically possible. The big challenge in this case was that there was no predecessor model on which we could base our development work.

Besides, we are operating in a very dynamic environment with constantly changing market demands, new technological framework conditions, and new competitors — whom we call “bus Teslas” among ourselves, and who may require a response.

If you want to be better than the others, you have to know the customers’ demands and wishes very well and analyze them carefully. We conducted discussions with transportation company representatives all over Europe — from Scandinavia with its freezing winters to major cities such as Barcelona with its extremely hot summers. We looked at e-mobility from the customers’ perspective and brought the transportation companies’ expectations into line with our technical capabilities.

Customers want not only reliability but also a range that is as wide as possible and, above all, can be reliably calculated over the entire year. In an electric city bus, the climate control system can double or even triple the energy consumption during periods of high temperatures and especially during periods of freezing cold. As a result, designing an electric bus with these framework conditions in mind is the key to success.

Mercedes-Benz eCitaro: Practice-oriented ranges

That’s because we want the driver and the passengers to be comfortable — but also because the batteries must stay at a comfortable temperature so that they can provide maximum performance. However, the first consideration is that long ranges under demanding climatic conditions require a high battery capacity. Batteries are by far the most expensive components of a bus. They are also heavy, and this decreases the load capacity, and thus the passenger capacity, of the bus. We had to resolve these conflicting objectives.

The result of our work is the eCitaro. From the very start, we achieved ranges for this bus that correspond to practical conditions. And we managed to do this not by using gigantic battery packs but by optimizing the energy consumption. The trick that our developers used was thermal management — in other words, the climate control system of the eCitaro.

As anyone can imagine, it takes an enormous amount of energy to control the climate of the glassed-in passenger compartment of a 12-meter-long city bus. This is especially difficult if two or three very wide doors are opening up every 400 meters along the bus route, on average. That costs battery capacity.

So our colleagues optimized the range of the bus by drastically reducing its energy consumption thanks to a new thermal management system. Here are two examples of that: The bus is heated by a heat pump of the same kind that is used in energy-saving houses. It’s cooled by a very efficient CO2air conditioning System.

I saw a prototype of the eCitaro for the first time in 2016. The testing period was very exciting, because of course the eCitaro has to run just as reliably as the Citaro with a conventional drive system, in spite of its new technology. That’s why the colleagues operated the bus at temperatures below zero at the Arctic Circle and high temperatures in the Sierra Nevada.

I participated in a test at the testing grounds in Wörth. The aim was to define the acceleration of the bus. This is an important area, because the high torque of the electric motors from a standing start means that a city bus can accelerate so fast that it feels like a Mercedes AMG. However, such quick starts wouldn’t make any sense in urban traffic with passengers standing in the aisle.

Now the eCitaro departs from its stops swiftly but smoothly. This adjustment was checked in an additional test on the Hockenheimring race circuit. In this test, an eCitaro was compared with a diesel-powered Citaro. And on this occasion I had the opportunity to drive the e-Citaro myself for the first time. It was a fascinating experience.

Futuristic Design

The appearance of the eCitaro was supposed to be kept secret until the official world premiere. The design of the eCitaro is ultimately based on the concepts of the spectacular autonomously driving Mercedes-Benz Future Bus, which we presented in 2016.

The e-Citaro designers picked up many ideas from it and refined them. In my opinion, the eCitaro looks very elegant. One of its unusual style elements is the simulation of a radiator grille with three-dimensional decorative slats that turn different colors as the light changes.

It was always impressive to see how the whole team at Daimler Buses — design, development, and all the other departments — supported the project to develop the eCitaro. All of our colleagues realized that they were working to create a very special bus. All of them pulled together and supported one another. That’s why the eCitaro is the result of a genuine team effort.

On the day after the world premiere, our customers will have the opportunity to see the new eCitaro for themselves in Mainz. The logical consequence of our many years of work, as well as its reward, should be the customers’ interest in buying the bus and good turnover figures.

Meanwhile, the countdown is continuing: We’re already working on variants such as an articulated eCitaro city bus. The rapid progress of battery technology is leading to the fact that further developments with even better performance are now officially on our agenda.

Our efforts will be crowned by the eCitaro that uses a fuel cell as a range extender. The world premiere in Mainz is only the beginning of the fascinating development of electric mobility in cities.

Daniel Bäuerle works as an employee in the product planning and product management for alternative drives at Daimler Buses, where he is responsible for the Electric Drive Bus project. What he likes best on his job are the different tasks and the various arrangement options. In his freetime he likes to go skiing and plays handball in a club.