Mercedes-Benz Buses: eCitaro: In the event of danger

E-mobility in series production

For the most important person on board.

The driver must react fast to the threat of an accident, in order to avert the danger. The Citaro provides assistance with its directionally stable suspension and smooth steering, This is achieved by the independent suspension on the front axle.

The pendulum impact test in accordance with UNECE-R 29.

The pendulum impact test in accordance with UNECE-R 29. There is particular emphasis on driver safety in the new eCitaro. The UNECE-R 29 Directive applicable to trucks, which has defined the survival space for the driver in a head-on collision in a truck since 1975, has been voluntarily adopted as the standard for the eCitaro. Compliance with UNECE-R 29 is checked through a pendulum impact test.

Protection in the event of a head-on collision based on the UNECE-R 29 standard, unparalleled amongst urban regular-service buses, as well as the even stiffer structure of the frame, increases passive safety.

Fire detection system.**

The new eCitaro is equipped as standard with a fire detection system in the engine compartment which monitors the prevailing temperatures there. If the preset value of 160 °C is exceeded, the pressurised detection line breaks and warns the driver of the imminent danger by means of an audible alarm and visually in the driver's display with the message "Engine compartment fire detected".

A malfunction affecting the vehicle's operational readiness as well as an activation of the system, e.g. during a period of the bus being parked unsupervised, the driver is informed via the message "Failure of fire detection system" also being shown in the display.

Fire extinguishing system for the engine compartment.*

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.