Data bus  

The data bus is used for rapid exchange of all possible information between sensors, actuators and control units etc. in the vehicle. It ensures that information from one sensor can be passed on to several control units via digital exchange and processed in said control units. This greatly reduces the risk of a complete breakdown.
An example of how this works, for instance, is the rain sensor: if this says ‘it’s raining’, the data bus activates the wiper, brake disc wipe function, windscreen ventilation and light.

Daytime headlights  

Additional light reducing the risk of an accident in daylight.
Daytime headlights:
Dipped beam headlight switched on during the daytime
Daytime running light:
Separate light built into the headlight
The functions switch on automatically when the engine is started.

Front view of Volkswagen at night, headlight detail

Daytime running light 

Additional light reducing the risk of an accident in daylight

Daytime running light
Separate lights built into the headlight or bumper. The Passat and Polo are examples of vehicles with daytime running lights in their bumpers.

Daytime headlight
Dipped beam headlight switched on during the daytime

The functions switch on automatically when the engine is started.

VW Touran viewed from front with headlight with LED daytime running light on a parking space, an industrial area in the background

Diesel direct injection  

In diesel direct injection, the fuel is injected directly into the combustion chamber. Diesel with direct injection is currently the most efficient combustion engine with the highest level of efficiency. With high-pressure injection, the diesel engine finally reached a level of performance that is comparable with modern petrol engines with exhaust gas turbocharging.

See also:

Image of direct fuel injection

Diesel particulate filter

A diesel particulate filter is a system for removing diesel soot from diesel engine exhaust gases.
The filter with the catalytic coating operates without additives and uses a filter coating containing precious metals that works in two ways. Passive regeneration involves a slow, gentle conversion of soot in the catalytic converter into CO2. This process takes place within a temperature range of 350 - 500 °C and runs continually without special measures being taken, primarily in mainly motorway operation.
Only in longer operation with low load, such as in city traffic, does an active increase in exhaust gas temperature to around 600 °C ensure additional filter regeneration every 1,000 to 1,200 kilometres. The particulates stored in the filter burn off at this temperature.

See also:
Catalytic converter

Image of the diesel particulate filter in a Volkswagen

Differential lock  

A differential balances different wheel speeds in the case of driven axles.
Different wheel speeds occur when the wheels on one axis cover distances of different lengths when taking a corner. So, for instance, the wheel on the outside of the corner is turning faster than the wheel on the inside. In most cases, a bevel wheel differential balances speed on driven axles. A differential lock prevents one wheel from turning freely and directs the force to the wheel with better traction. Speed balancing can be blocked manually or automatically up to 100%. This means that on a slippery surface, for instance, up to 100% of the force can be directed to the wheel with the best traction.