Lambda refers to the air-fuel ratio in the combustion engine (stoichiometric ratio). The optimum chemical ratio is lambda=1, when it is 14.7 kg air to 1 kg fuel (for petrol).
As a sensor, the lambda probe is capable of measuring this ratio. It is responsible for the proper running of a catalytic converter.
The probe sits in the exhaust gas train outside the catalytic converter and measures the exhaust gas composition from the residual oxygen content. Based on this value, the engine control unit controls the blend composition for the injection system.
‘Lane Assist’ lane keeping system
The ‘Lane Assist’ lane keeping system helps, within the system's limitations, to avoid accidents caused by accidentally leaving the lane and greatly increases safety on motorways and well-developed country roads. If it appears that the vehicle is unintentionally leaving its lane, ‘Lane Assist’ warns the driver with a visual signal.
‘Lane Assist’ also continually countersteers slightly, depending on the vehicle. If the force of countersteering is not enough to keep the vehicle in lane, the driver is also warned by a vibration in the steering wheel. If the system does not detect any clear active steering movements from the driver for a longer period of time, it makes an audio and visual takeover request in the instrument cluster and switches off.
From a speed of 65 km/h, a camera in the interior mirror area records road markings – this applies to solid lines and dashed markings (such as those in the middle of the road). ‘Lane Assist’ also recognises the lane when there is only one marking. It can also detect lanes in dark or foggy conditions. However, if there are no recognisable road markings, the system does not work. The Lane Assist system also does not respond if the turn signal is activated before the vehicle drives over a marking.
The driver can ‘override’ ‘Lane Assist’ at any time with minimal use of force and is not released from the responsibility to drive the vehicle consciously.
Driver assist systems
Lateral acceleration sensor
To determine the current driving situation, Electronic Stability Control uses an acceleration sensor to measure the lateral acceleration impacting the vehicle. Lateral acceleration impacts a vehicle transverse to the direction of travel. When taking a corner, for instance, it can be felt as centrifugal force on the outside of the corner. The lateral acceleration sensor is contained in the same housing as the yaw rate sensor (duo sensor).
Electronic Stability Control
Leaving Home function
The dipped beam headlight, surrounding lights in the exterior mirror housings, tail lights and numberplate lighting are switched on when the driver unlocks the doors using the remote control (leaving home). This means the vehicle’s exterior lighting can be used to light the way to the vehicle in darkness.
Coming Home function
An LED (light-emitting diode) is a light-emitting semiconductor. The advantages of LED technology in comparison to conventional bulbs are lower energy consumption, shorter response times, lower spatial requirements and a higher lifespan.
At Volkswagen, LEDs are used in features such as tail light clusters, daytime running lights and turn signals in exterior mirror housing. LEDs’ high level of reliability and lifespan boost safety thanks to the reduced likelihood of faults in tail light clusters and brake lights.
‘Light Assist’ main beam control
With an automatic main beam headlight, ‘Light Assist’ ensures comfort and safety in traffic. A camera on the interior mirror monitors traffic. From 60 km/h and in full darkness, Light Assist turns the main beam headlight on by itself. The system detects vehicles in front and oncoming vehicles and automatically dips the beam before they are dazzled. The automatic switch from main beam to dipped beam ensures the road is illuminated as effectively as possible.