The transportation sector is ever growing as the mobility behaviour has significantly changed over the last decades. The number of daily trips has remained fairly constant, but at the same time the travelled distance increased. Compared to other sectors, the decoupling of greenhouse gas emissions from the rising mobility demand has not yet been successful so far.

HyPower aims to improve the powertrain layout of alternative electric/fuel cell hybrid HDV to enable a fossil free transportation and limit the overall energy consumption of the vehicle. Furthermore, the cost optimum for long distance HDV is achieved by an optimised balancing of the fuel cell (FC) and battery sizes as this ensures high mileage and a beneficial operation.

The current preferred ratio is a range extender FC drive. This leads to increased lifetimes of FC hybrid buses and trucks as unfavourable operation points can be limited in those driving profiles. In the long term, the FC to battery ratio in high mileage HDV would shift in favour of the FC dominant drive with a small battery similar to conventional diesel hybrid engines.

Thermal management of fuel cell systems is an issue for mobile applications mostly, which is due to the limit space in vehicles and discontinuous operation. In terms of thermal management, fuel cells have to compete with internal combustion engines that are still standard for vehicles. The radiator of a fuel cell powered HD truck must be almost twice as large, compared to a conventional diesel truck, to reject all the waste heat. Thermal management for fuel cells is not only important at normal operating temperature, but also during cold start, which will be a frequent operating mode of any vehicle. Especially at sub-zero temperatures, the cooling water needs to be heated to accelerate the start-up time of the PEMFC, governed by ice formation in the flow channels, blocking gas transport. Therefore, the thermal management is still a huge challenge for H₂-driven HD vehicles.

The overall objective is an optimisation of fuel cell vehicles (FCV) with a focus on the

• development of a simulation program for powertrain development and related requirements for heavy-duty vehicles (HDV) e.g. bus powertrains
• improvement of the accompanying thermal management system (TMS).
• development of a test procedure and the construction of a component as well as subsystem test bench in order to test balance-of-plant (BoP) components or hardware-in-the-loop (HiL) systems for their suitability under fuel cell (FC) conditions