Abstract
There is worldwide understanding that hydrogen has a great potential as the
fuel of the future. In addition to the challenge of developing appropriate hydrogen propulsion
systems, the development of hydrogen storage systems is the other big issue. The BMW
Group is focusing on the development of liquid hydrogen storage systems in view of their
high potential in specific cost, weight and storage capacity. The current BMW 7 series will
acquire a new family member based on a liquid hydrogen storage system in the near future.
With this vehicle the BMW Group is about to make the step for the first time from demon-
stration fleets to cars operated by non-specialized users. The solution of hydrogen safety
considerations is a key element in reaching this significant goal: special focus has to be put on
high safety standards so that hydrogen is considered as safe as common types of fuel. The
paper describes the measures undertaken to ensure the safety of customers and environment.
It provides an overview of the safety aspects of internal combustion engine (ICE) powered
motor vehicles with liquid hydrogen storage. The safety concept of the new BMW hydrogen
vehicle is introduced and discussed specifically. The architecture of the current cryogenic
hydrogen storage system under development is shown. Appropriate measures according to the
above-mentioned safety layers are defined for the vehicle and the storage system, and exam-
ples of the underlying tests presented. Finally, the closed-loop engineering process - consist-
ing of requirements, system and component design parameters, test specification, tests and
release according to requirements - is shown as a core "engineering for safety" measure. An
example from current development of the liquid hydrogen storage system is provided.
Keywords - Hydrogen, vehicle, safety, engineering, IEC 61508