Specifications

The reset of the hydrogen detector, i.e., the hydrogen sensor and its
electronics, must be done manually via a switch located in the fuel cell
compartment. This switch must not be accessible by the pilot from the cockpit.
Emergency shutdown valve and relay
The hydrogen supply circuit must be equipped with a solenoid emergency
shutdown valve. This valve must be normally closed in the absence of
electricity.
This valve must be located immediately after the pressure regulator. The
pressure regulator must be connected directly to the H2 cylinder.
The power supply to the motor must be automatically cut off at the same time
as the above emergency shutdown valve is activated. This is to be achieved by
a suitable fail-safe relay.
This valve and relay must be activated by any of the following three scenarios:
• Through hydrogen detection as explained above
• Through the emergency push-button located on the outside of the vehicle.
A red arrow at least 10 cm long and 3 cm wide must be positioned on the
vehicle body to clearly indicate the place of this emergency push-button.
(Note: It must not be part of the detachable bodywork used to allow driver
access)
• Through another emergency push-button, accessible by the pilot in driving
position.
In case of activation by one of these three scenarios, the valve and relay must
act simultaneously.
These three scenarios will be tested during the technical inspection and before
each attempt.
Pipes and connections of the hydrogen circuit
In all cases, piping and connectors of the hydrogen circuit must be designed for
hydrogen use. The Team Manager must be able to present during the technical
inspection the technical data sheets from the manufacturer of these piping and
connectors to show that they are suitable for hydrogen use.
If the pressure in the hydrogen circuit is higher than 1.5 bar absolute (=0.5 bar
above atmospheric pressure) piping must be made of steel and connectors
must be screw type.
If the pressure in the hydrogen circuit is lower than 1.5 bar absolute (=0.5 bar
above atmospheric pressure) flexible piping and unscrewed connectors are
accepted.
PTFE (Teflon) sealing tape must not be used.
Purge pipe
If a purge pipe is needed, its end must be located outside the vehicle.
Measurements and Equivalencies
The consumption of hydrogen is measured by an embedded flow meter. The
flow meter will be checked / calibrated by the Organisers before technical
inspections.
The flow meter has to be purchased from the Organisers.
Shell Eco-marathon ® Official Rules 2011 – Chapter 1
29
The volume of hydrogen consumed is posted in normal litres. The display of the
flow meter must be easy to read from outside the vehicle, when the vehicle
body is closed. It must be inaccessible by the pilot in normal driving position.