Mercedes-Benz has unveiled the eCitaro REX, a hydrogen-powered fuel cell bus that combines the benefits of battery-electric and fuel cell technology.
As an extension of the popular eCitaro battery-powered bus, the eCitaro REX integrates a fuel cell system alongside its large traction battery, offering enhanced range and operational flexibility. With its official launch scheduled for June 2023, the eCitaro REX is set to revolutionize the public transportation sector with its sustainable and efficient design.
The primary objective of the eCitaro REX is to provide an electric bus solution capable of extended range, making it an ideal choice for transport companies serving longer routes without the need for frequent recharging or additional buses. The articulated variant of the eCitaro REX, available from June, can travel approximately 350 kilometers on a single charge, accommodating up to 128 passengers. This groundbreaking development paves the way for the seamless replacement of conventional combustion engine buses in urban areas, significantly reducing emissions and improving air quality.
At the heart of the eCitaro REX is a battery-electric drive system featuring NMC 3 high-performance batteries. This setup is augmented by a 60 kW fuel cell, which acts as a range extender. Mercedes-Benz emphasizes the cost-effectiveness of this hybrid configuration, as grid electricity is typically more affordable than green hydrogen. The sophisticated electronic control system optimizes the balance between battery power and fuel cell operation, ensuring efficient energy usage.
The integration of a fuel cell range extender in the eCitaro REX offers several advantages compared to a purely battery-electric bus. Notably, the vehicle can maximize energy regeneration through braking, efficiently storing the recovered energy in its large battery system. Furthermore, the eCitaro REX’s substantial battery capacity, reaching a maximum of 392 kWh in the articulated variant, allows for robust performance over longer distances, such as uphill climbs in mountainous regions. This minimizes reliance on the fuel cell, which operates less efficiently at higher power ranges.
Before hitting the streets, the eCitaro REX underwent rigorous testing to ensure its safety and functionality, particularly concerning the fuel cell and hydrogen system. The hydrogen tanks were subjected to rigorous assessments, including fire, impact, and temperature resistance tests following the UN ECE R 134 standard. Vibration and carriage tests were also conducted to simulate real-world impacts, verifying the durability and stability of all components, including the roof-mounted fastening system.