Citaro

Acceleration skid control (ASR)

There are two ways in which ASR prevents the drive wheels from spinning. First of all it minimises wheel spinning using metered brake force. Secondly it also regulates the engine's torque via the electronic gas pedal. Even at full throttle the engine provides only as much output as the drive wheels can transfer – a big advantage for safety when starting off and for handling.

Anti-lock braking system (ABS)

How ABS works: all four wheels are equipped with sensors which identify the rotational speed of the wheels and transfer this information to the central control unit. If a sensitive point is reached during braking and the wheels are blocked, the wheel is maintained at this threshold by varying the pressure. The brake pressure can be built up and released again several times within one second.

During braking the force acting upon all the wheels and their rolling behaviour is recorded. The braking power is distributed in such a way that no wheel becomes blocked and the vehicle retains most of its manoeuvrability.

The Electronic Stability Program (ESP^®)

The Electronic Stability Program ESP^® is an active system which improves handling safety and stability. It contributes significantly to reducing the risk of skidding when negotiating turns or making evasive manoeuvres. It does this in critical handling situations through targeted braking interventions at each individual wheel, for instance if the bus is moving at critical limits in a curve. At the same time the engine output is reduced, with the effect that precisely regulated braking interventions prevent the bus from skidding, as far as this is physically possible.

ESP^® monitors factors such as the lateral acceleration of the bus. If a critical handling dynamic situation is reached in lengthy curves – such as motorway exits – or when making a sudden change of lane, the vehicle's speed is automatically reduced to a level that re-establishes handling stability. The ESP^® is comparable to that used in passenger cars, but is adapted for use in buses thanks to specific extended features.

Roll-and-pitch control, the control for more stability.

Roll and pitch control is also available for the Citaro as special equipment. This enhances vehicle stability and makes for added safety and ride comfort.

This feature works by adjusting the shock-absorber response in accordance with the driving situation and load status, thus both reducing the incidence and accelerating the attenuation of undesirable rolling, pitching and linear travel of the vehicle body.

When braking or cornering at speed, for example, the damping is firm to provide additional handling safety. In other situations, the dampers have a softer response and thus support the Citaro's outstanding ride comfort in accordance with the prevailing situation.