Camshaft adjustment 

The job of the camshaft is to operate the valves at the right time and in the correct sequence, thus controlling the gas exchange. The camshaft adjustment adapts the valve opening times to the best possible setting for all operating conditions.

This helps achieve the ideal gas exchange at a wide range of engine speeds and loads. This reduces fuel consumption and emissions and increases torque and running comfort. In engines with two camshafts on top, the size and location of the valve overlap can be impacted and behaviour in operation with a part or full load can be improved accordingly.

Constant cam shaft adjustment enables seamless adjustment within certain limits.

Image of the cam shaft in a Volkswagen

Car-Net App-Connect  

Car-Net App-Connect allows a smartphone to be connected to the Composition Media radio system or the Discover Media and Discover Pro navigation systems with ease. This allows the user to operate selected apps from their smartphone using the touchscreen.
Car-Net App-Connect integrates three interfaces for smartphone connection: MirrorLink™, Google’ s Android Auto™ and Apple’s CarPlay™. This means all current smartphones from Android 5.0 and Apple iOS 8.1 onwards are compatible.

Image of the on-board computer of a VW Golf, Car-Net App-Connect detail

Car-Net Cam-Connect

Car-Net Cam-Connect is an app which allows you to view a still image from the rear of the vehicle on the infotainment system display during the journey. At walking speed or at a standstill, the app even shows a video.

A prerequisite for this is the integration of a GoPro® camera.

Image of the on-board computer of a VW Golf, Car-Net Cam-Connect detail

Car-Net Guide & Inform  

Car-Net ‘Guide & Inform’ services offer the best information on the move. ‘Guide & Inform’ includes Online Traffic Information, Online Destination Important, Online POI Search, News and Weather and allows the user to enter their own personal POIs.

Discover Media with Car-Net Guide & Inform screen

Car-Net Security & Service  

Car-Net ‘Security & Service’ offers mobile access to relevant vehicle data and functions and makes this available on a web portal.
The useful functions of this service bundle at a glance:

  • Lock or unlock1 the vehicle, even from a distance, with ease using a smartphone.
  • Save and relocate parking position
  • Check vehicle status such as mileage and fuel level using a smartphone
  • Anti-theft alarm via email or push notification2
  • Automatic emergency call passing on vehicle location and data and the number of people (for accidents with triggering of the airbag) 
A man in a high-visibility waistcoat leaning on a Volkswagen waiting for the emergency services

Catalytic converter 

‘Catalytic converter’ is a term commonly used to describe the entire emission control system in cars. It contains an effective catalytic chemical substance (usually a precious metal such as platinum or rhodium), ceramic or metallic substrate, a housing and, depending on the design, different process control units. Depending on the design, the catalytic converter oxidises carbon monoxide to carbon dioxide, hydrocarbons to carbon dioxide and water and/or reduced nitrogen oxides to nitrogen and oxygen gas. Effective catalytic converters reduce pollutants in exhaust gas by up to 90 per cent.

In cars, three-way catalytic converters (petrol engines), oxidising catalytic converters, NOX storage catalytic converters and SCR systems (diesel engines) are all used - with up to two main and four starter catalytic converters, depending on the engine. To do its job efficiently, the three-way catalytic converter requires a specific operating temperature. This is why vehicles use close-coupled starter catalytic converters, which reduce harmful emissions as early as the engine's warm-up phase.

The lambda probe combined with the engine control unit control the optimum composition of the petrol-air mixture for conversion.

See also:
Lambda probe
Oxidising catalytic converter
NOx storage catalytic converter
SCR catalytic converter

Image of a Volkswagen catalytic converter

Central locking 

The central locking remote control offers maximum convenience. It can be used to lock and unlock all vehicle doors and the boot lid via a wireless signal. Depending on equipment, a simple setting also allows unlocking to be limited to the driver door (single door unlocking).
Access to the tank flap is also automatically controlled with the central locking commands. The boot lid can be opened individually where required using a separate button on the remote control. The vehicle’s locks are designed to ensure that once they have been locked using the remote control, doors can no longer be opened using the inner door handle, dramatically improving anti-theft protection. The lock button inside the vehicle also protects against robberies. In a dangerous situation, this allows the driver to lock all the doors and the luggage compartment at the same time from the inside with a quick press of a button.
Access to the luggage compartment is blocked by the central locking when the vehicle starts, preventing unauthorised access at traffic lights or in traffic jams. The block is automatically lifted again once the ignition key is removed or someone leaves the vehicle.
Speed-based automatic full locking can also be activated. This locks all doors and the luggage compartment as soon as the vehicle is travelling faster than 15 km/h. In that case, unlocking also takes place automatically once the ignition key has been removed or one of the occupants opens a door.

Central locking in a VW Touareg

Centre differential 

In order to balance the different rear and front axle speeds resulting from different curve radii or occurring in off-road driving, the all-wheel drivers (4MOTION) have a transfer box with a differential function. It can prevent tension in the drive train and distribute driving forces, within the system’s limitations. This allows the wheels to gain more force with improved traction conditions.

Due to different requirements, different designs are used in 4MOTION:

  • All-wheel drive coupling or
  • Torsen differential

See also:
Torsen differential
All-wheel drive coupling


The Cd value is the drag coefficient. It is determined in the wind tunnel and sums up a vehicle’s aerodynamic properties. It is used as a comparable measure to describe the ‘shape quality’ of bodies – irrespective of their sizes.
This value is affected by different factors, such as the body shape (saloon, van or hatchback). Narrower gaps and spaces reduce turbulence and facilitate low drag coefficient. The design of the underbody also has an impact on the Cd value.
The lower this value, the more streamlined the vehicle design. However, an exact conclusion on aerodynamics can only be drawn when the vehicle’s Cd value and end face (projection of its front view on a surface) are indicated. A small vehicle may have a poorer Cd value than a large saloon. Due to its smaller end face, its drag may be lower.

See also:

VW Golf R on a racetrack, front view

Charge air cooling  

Charge air cooling reduces the engine’s thermal load. Compression of fresh air during turbocharging increases the temperature in the charger. As heated air takes up more space than cool air, the cylinders subsequently fill with less air than corresponds to the charge pressure and the tendency to knock rises in petrol engines. Accordingly, the compressed air is cooled by the engine coolant or outside air. Charge air cooling also reduces NOx emissions and fuel consumption.

Charging cable

Simply insert the plug of the charging cable into the vehicle’s charging socket when charging your electric vehicle at home on the optional wall box in your carport or garage. The charging process automatically starts as soon as the electrical connection has been established. This is similar at stations that employers possibly provide. A charging cable should already be permanently installed here. By contrast, there is often no charging cable at many public charging stations. You then simply use the charging cable supplied with the vehicle.

Illustration of a charging cable for the ID.3

Charging capacity

The simple rule of thumb is: the higher the charging power, the faster the charging process. However, the time needed can vary considerably, depending on the battery charge state. For example, when the ID.3 is charged at a household/standard European plug socket, it is charged at 2.3 kW per hour. It is quicker with a wall box (up to 11 kW/h) or AC charging station (22 kW/h).
The High Power Charging Stations (HPC) with a power output exceeding 100 kW provide the fastest charging.

Charging card

Apart from paying by app or credit card, the charging card is a convenient way of paying for current at public charging stations. In future, customers will be able to obtain power at around 100,000 stations all over Europe with the Volkswagen We Charge charging card.

Illustration of a payment process at a charging station

Charging connector

There are two established types of charging connector: Mennekes connector and Combo-2 connector.
The “Mennekes connector” (type 2, in picture right) is designed for slow charging and complies with the European standard for AC charging. Many public charging stations now have at least one type 2 socket.
The connector known as the “Combo-2 connector” (in picture left) is the standard for fast DC charging in Europe. With additional contacts, it provides for fast DC charging at public charging stations with a DC charging power of more than 22 kW.

Illustration Mennekes Connector  and Combo-2 Connector

Charging stations

There are both private and public charging stations. The most common method of private charging is via the optional wall box in the home, carport or garage. It provides a higher AC charging power than charging using the cable supplied at a household socket and is also very convenient to use. The battery charge is paid for with the next electricity bill. Public stations, which might be provided by employers, generally have a permanent charging cable fitted. This current is generally paid for using a charging card if the employer is not supplying the electricity free of charge. If there is no permanent cable fitted at public charging stations, you simply use the charging cable supplied and either pay by charging card or app (using the NFC standard or QR code). Alternatively, ad hoc charging can be paid for directly to the operator of the charging station e.g by credit card.

Illustration of a public charging station

City Emergency Braking System  

The City Emergency Braking System provides assistance at speeds below 30 km/h. If the driver misses an obstacle detected by the sensor, the system brakes the vehicle automatically and reduces impact speed, within the system’s limitations. Ideally, this should help prevent collisions entirely.

See also:
‘Front Assist’ area monitoring system

Two Volkswagen vehicles seen from above at night. The City Emergency Braking System sensor system is shown using lines

Climbing power 

A vehicle’s climbing power is its ability to climb a gradient. Climbing power is measured either in degrees or as a percentage. A 45° gradient is the equivalent of 100%. It depends on the engine performance, drive type, gear ratio, weight, weight distribution, vehicle centre of gravity and traction.

See also:
Breakover angle
Cross slope
Ramp angle

A VW Touareg climbs a road with a 45° gradient

CNG (Compressed Natural Gas)  

The fuel available with the name CNG (Compressed Natural Gas) is based on natural gas. It is available in Germany in two forms:

  • H-gas: High calorific gas = higher energy content
  • L-gas: Low calorific gas = lower energy content

The higher energy content of H-gas allows for longer ranges than with the same quantity of L-gas. By 2029, the majority of ‘L-gas’ regions, which are primarily found in the north and west of Germany, will also be switched to H-gas.

Difference between natural gas (CNG) and Autogas (LPG)
Primarily composed of methane, natural gas is the hydrocarbon compound lowest in carbon. It is lighter than air, escapes upwards and evaporates accordingly. This means that in principle, vehicles with a natural gas drive are permitted in any underground car park in Germany, according to the regulations on parking garages in the individual German states.
The energy content of a kilogram of natural gas (H-gas: 14 kWh/kg) is the equivalent of around 1.5 litres of petrol or 1.3 litres of diesel. Natural gas contains almost twice as much energy as liquefied petroleum gas (7 kWh/l).
Unlike natural gas (CNG), Autogas (LPG) is a by-product of oil and natural gas extraction and heavier than air. This means that there is a risk of gas collecting on the ground or in recesses. This means that it is often not permitted to park LPG vehicles in underground car parks.

Schematic diagram of CNG (Compressed Natural Gas) in a Volkswagen
Fuel consumption Golf GTI natural gas (CNG), kg/100 km: urban 4.8
– 4.4 / extra-urban 3.1 – 3.0 / combined 3.6 – 3.5; CO₂ emissions
combined (natural gas (CNG)), g/km: 98 - 95; Fuel consumption (petrol),
l/100 km: urban 7.3 – 6.6 / extra-urban 4.6 / combined 5.6 – 5.3; CO₂
emissions combined (petrol), g/km: 127 - 122; efficiency classes: A, A+

CNG vehicles

Volkswagen offers vehicles with natural gas drives under the TGI (and eco up!) names.
All engines are optimised for running on natural gas. This reduces consumption and has a positive impact on emissions. Natural tanks are integrated as compact underfloor solutions and only slightly limit variability and interior or loading volume slightly.

5. Fuel consumption eco up! (natural gas (CNG)), kg/100 km: urban 3,7 - 3.6 / extra-urban 2.6 / combined 3.0 - 2.9; CO₂ emissions combined, g/km: 82 - 81; efficiency class: A, A+
4. Fuel consumption Golf GTI natural gas (CNG), kg/100 km: urban 4.8 – 4.4 / extra-urban 3.1 – 3.0 / combined 3.6 – 3.5; CO₂ emissions combined (natural gas (CNG)), g/km: 98 - 95; Fuel consumption (petrol), l/100 km: urban 7.3 – 6.6 / extra-urban 4.6 / combined 5.6 – 5.3; CO₂ emissions combined (petrol), g/km: 127 - 122; efficiency classes: A, A+
6. Fuel consumption Polo GTI natural gas (CNG), kg/100 km: urban 4.4-4.1 / extra-urban 2.9-2.7 / combined 3.4-3.2; CO₂ emissions combined (natural gas (CNG)), g/km: 93-88; efficiency class: A+

See also:
CNG (Compressed Natural Gas)
TGI natural gas vehicles

Three Volkswagen natural gas vehicles


Carbon dioxide (CO2) is a colourless and odourless gas produced during combustion processes. As a chemical compound consisting of carbon and oxygen, CO2 is regarded as one of the main causes of the greenhouse effect and global warming.

Discover media screen with Car Play on screen

Coasting function  

The coasting function is designed to help make better use of the vehicle’s kinetic energy.
In zero-load driving situation (foot off the accelerator), the engine is disengaged itself and kept at idling speed. The vehicle may then roll for a further distance that does not then need to be covered by the use of fuel. The advantage for consumption in practical vehicle operation stems from the fact that the vehicle’s kinetic energy is only used to overcome roll resistance and drag and is no longer used to draw the engine at high speeds. If the driver indicates a wish to slow down by pressing on the brake, the engine is engaged again in order to benefit from overrun fuel cutoff; the fuel supply is interrupted and the engine braking effect shortens the vehicle’s rolling distance again. The minus button on the steering wheel can also be used.
Savings of 0.5 l/100 km and over are sometimes achieved. The efficiency of the function depends on driving with foresight; after a short period of adjustment, the driver adapts to their vehicle’s longer coasting distance and intuitively take their foot off the accelerator earlier, for instance, when entering a town or village.

VW Golf centre console

Conductive charging

Conductive charging is also known as wired charging. The vehicle is connected by a cable and plug to the power grid.

Illustration of an ID.3 on a wallbox

Comfort Brake Assist (HBA) 

Volkswagen's comfort Brake Assist assists the driver in the event of an emergency or panic brake situation. Based on the speed of pressing on the brake pedal, the hydraulic Brake Assist system (HBA) detects whether the driver wishes to brake hard and increases the brake pressure automatically to the ABS control area while the driver presses the pedal. If the driver eases pressure on the brake, the system reduces the brake pressure to the standard once again.

The comfort Brake Assist system can dramatically reduce the stopping distance. The system operates almost imperceptibly for the driver.

See also:
Electronic Stability Control

Image of HBA indicator lamp

‘Comfort’ mobile phone interface  

The ‘Comfort’ telephone interface offers numerous extras which make hands-free telephone calls even easier. Charging is nice and easy, too: simply place the telephone in the dedicated stowage area and connect it to the USB port there. The external aerial connection helps ensure outstanding reception. The system can be controlled using either the multifunction display, the multifunction steering wheel or the navigation system.

See also:
‘Business’ mobile phone interface

Interior of the VW Golf with the ‘Comfort’ mobile phone interface, a man’s hand on the gear lever

Coming Home function  

When the driver leaves the vehicle, the dipped beam headlight, surrounding lights in the exterior mirror housings, tail lights and numberplate lighting switch off more slowly (coming home) or 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 door of the house or the vehicle itself in darkness.

See also:
Leaving Home function
Remote control

Front view of the VW T-Roc at dusk

Common rail system

The term ‘common rail’ refers to a specific direct fuel injection design in diesel engines. In this design, pressure generation and fuel injection are kept separate. A separate pump that can be installed in a preferred position on the engine constantly generates pressure. This is stored in a distributor unit. Connectors are used to link the injectors on all cylinders in parallel with the distributor unit, known as the ‘common rail’. Constant pressure is supplied without interruption to the injectors in all cylinders. Injection quantity and time are controlled using solenoid valves on the individual injectors.

Image of direct fuel injection

Concept car / Show car / Concept vehicle

A vehicle described as a concept car or show car is used to showcase an automotive design project and is not intended for sale. Concept vehicles are generally exhibited to the trade public at automotive trade fairs and present a vision of future developments.

Contactless high-voltage battery charging

Contactless high-voltage battery charging is also known as wireless charging. Many research institutes, as well as Volkswagen, are currently working on this technology for the wireless transfer of energy for the future of electric mobility.

Convenience opening/closing 

When locking or unlocking the vehicle, all electrically operable windows (and, in some models, the electric sunroof) can be opened or closed at the same time. To do this, simply press and hold the opening or closing button on the remote control. Opening and closing will stop when the button is let go. The same applies to operation with the key in the lock.

See also:
Remote control
Central locking

Image of VW Golf car key

Cornering light

When the steering wheel is turned or the turn signal is on, the static cornering light is automatically switched on, depending on the situation, at junctions or intersections below 40 km/h. This means the driver sees passengers, who are found particularly often beside the vehicle in turning situations, significantly quicker, reducing the risk of accident. Depending on the model, the cornering light can be built into the headlights or the fog lights.

See also:
Bend lighting

A Volkswagen on a street by night from above. The headlights’ front and cornering light are shown as a beam of light.

Corrosion protection 

Comprehensive corrosion protection for all relevant areas of the vehicle is now standard at Volkswagen. As well as galvanisation, body cavities are protected by being hot waxed. Body welds and the vehicle underbody are also sealed. Plastic wheel housing inserts, high-quality primers and modern top coats protect against stone chipping.

Corrosion protection ensures that the structure remains robust for the entirety of a vehicle’s service life and helps save resources thanks to its longer lifespan.

VW Passat Alltrack front tyres

Crash test  

When developing new vehicles, crash tests help determine the best ways to protect vehicle occupants. At the same time, corresponding pre-production cars for subsequent production vehicles are checked for different types of accident.
However, before the real attempt takes place, a simulation, or virtual crash, is performed on a computer. This results in important findings on how components interact if the worst comes to the worst. The following must be determined:

  • passenger compartment rigidity
  • emerging acceleration processes
  • adapted passenger protection systems

The results of all crash tests form the basis for continuing development aimed at boosting passive safety further. Medical specialists and experts in accident research, as well as engineers, are involved in this process.

See also:
Passive safety

A Volkswagen doing a crash test

Cross slope 

Cross slope refers to inclined vehicle positions on a slope.

Schematic diagram of the cross slope using the Touareg as an example

Cruise control system (CCS)  

The cruise control system is an electronic assist system to control vehicle speed.
The system saves and maintains the driver's chosen speed. They can then also temporarily increase or reduce the speed manually by a set amount and then return ⎼ if preferred ⎼ to the last saved speed. The cruise control system is deactivated using the ‘Off’ button or pressing on the brake or clutch pedal. The CCS offers the driver substantial added comfort, particularly on long journeys, at the same speed. It also makes it easier to stick to a set speed (e.g. in motorway works) and reduces the risk of driving too fast.
The cruise control system should not be used in heavy traffic and unfavourable road conditions (slippery surface, wet surface, etc.) for safety reasons.

See also:
Adaptive Cruise Control ACC

Image of the cruise control system in a VW Golf

Cycle stability  

The cycle stability describes the number of charging and discharging cycles a battery cell can undergo before its capacity falls below a certain percentage of its initial capacity.