In recent years, there is an increasing global interesting in alternative sources of energy. For this reason, Shell Company creates Shell Eco Marathon, a competition for fuel-efficient vehicles designed by student around the world. IDRAkronos is a fuel cell hydrogen prototype developed at the Politecnico of Turin. The vehicle races in prototype category with the task to complete ten laps of an urban circuit driving a total distance of 15 km in a maximum time of 39 min, then with an average speed of approximately 25 km/h, obtaining the less consumption. The vehicle is a three wheels vehicle based on a carbon fibre monocoque pushed by a hydrogen fuel cell with a high efficiency DC electric motor. The paper describes modelling and optimization of the powertrain design applicable to the development of fuel cell electric vehicles. A 1D-simulation model of the vehicle and its subsystems (fuel cell, electric motor, tires, aerodynamic, etc.) has been carried out in AMESim to analyse the behaviour of the vehicle during the race. The optimization leads to find the right combination of all parameters to achieve the least fuel consumption, considering the constraints of time, highest velocity, for example to perform a corner, and physical limit of the electric motor and fuel cell. Finally, the simulation results have been validated with the results obtained on the track during the competition.