Daimler Buses debut ‘H2 mode’ fuel cell feature

The new driving mode enables eCitaro G articulated electric buses equipped with fuel cell range extenders to operate exclusively using the hydrogen fuel cell - removing the need for external battery charging. Daimler Buses states that this increases operating range and efficiency of the fuel cell. Ten eCitaro G buses featuring this drive mode have recently been delivered to SSB Stuttgart.

daimler buses mercedes benz ecitaro g elektrobus electric bus 2024 001 min — Image: Daimler Truck

The previous models of the eCitaro G were the only Daimler buses to feature the fuel cell system, which could only be used as a range extender to charge the batteries while driving. Apart from that, it could only be driven using battery-electric power. What the H2 mode enables the vehicle to do is use the electricity from the fuel cell directly in the electric motors.

Each vehicle is equipped with four NMC3 battery packs with a total capacity of 392 kWh. Daimler states that the new eCitaro G also has improved regenerative brake charging while using H2 mode, which it claims aids the vehicle’s performance in stop-start urban traffic or on challenging uphill terrain. Six tanks featuring a total capacity of 30kg of hydrogen are located on the roof of each bus.

The full range of applications that the H2 mode offers could potentially be limited, however. In H2 mode, the fuel cell can only operate at a max of 40 kW, which is low even for a car. So it may only be enough power to maintain inner city speeds of 30 – 50 kph, with the battery still required to provide a dynamic response and provide more power during acceleration.

The first ten new H2 fuel cell buses have now been presented in Stuttgart to the public transport agency SSB, which has ended its purchases of diesel buses and aims to exclusively operate emission-free buses in the Stuttgart city centre from 2027. Daimler Buses stated it had evaluated the planned routes for the new vehicles and advised SSB on where they would be most efficient.

Upon deployment in Stuttgart, the vehicles will feature 47 passenger seats in blue-yellow fabric covers and 77 standing spaces, holding up to 124 passengers per bus. The vehicles also feature a rear camera, a surveillance system, Sideguard and Frontguard Assist, Traffic Sign Assist, Attention Assist and a tyre pressure monitoring system. Additionally, they will feature a manually operated folding ramp for accessibility and two special-use areas for wheelchairs and prams.

daimlertruck.com