If a temperature of approximately 160 °C is exceeded, the driver sees an alarm in the driver's display as well as the message "Engine compartment fire". Additionally, an acoustic warning tone is emitted and the extinguishing process initiated automatically.
In the case of a fire, the pressurised detection line (Firetrace) breaks and sprays an extinguishing mixture made of water, engine coolant and a special additive via a series of nozzles around the entire engine compartment. The water mist evaporates as a result of the high temperatures and displaces the oxygen. The engine compartment is thus cooled rapidly, the fire extinguished immediately and re-ignition of the fire prevented.
The fire extinguishing system uses the cleanest type of extinguishing agent: water. The water, the high pressure and a foam additive attack all three chain reaction conditions that cause a fire: heat, oxygen and fuel. The system cools the fire – by forming water vapour from a high-pressure water mist, which absorbs energy. Furthermore, it smothers the fire – by forming water vapour, which displaces the oxygen. With a foam additive that forms a protective film over combustible material, it prevents the fire from reigniting.
The fire extinguishing system is certified by TÜV and fulfils the legal requirements and test regulations of UN R107/06.