Headlight switching, automatic  

Automatic headlight switching ensures optimum vehicle lighting at all times without requiring the driver to manually activate or deactivate the headlight. The system offers the driver a significant boost in terms of comfort and safety. The main beam headlight is switched on automatically using a twilight sensor in encroaching darkness or when travelling through tunnels in the daytime. The main beam headlight is also activated when it rains (constant wiping for longer than five seconds) or when driving at high speeds (speeds of over 140 km/h for longer than 10 seconds). If the speed falls or the wiper is switched off, the system activates the headlight itself after a short time. This makes the driver’s vehicle easier for other drivers to detect.

VW up! front view, headlight detail

Headlight washer system 

In the headlight washer system, an electrically operated centrifugal pump sprays highly pressurised water or cleaning fluid from outside onto the headlight panel. This improves visibility in rain, snow or airborne dirt considerably. In xenon headlights, the cleaning system is legally prescribed.
In some models, this is cleaned gradually in two stages. When the washer jets come out, the first cleaning solution loosens the dirt. The second stage rinses off the loosened dirt. This means the beam of light is only slightly impeded by the cleaning process and optimum cleaning performance is ensured even at high speeds.

See also:
Bi-xenon headlights

VW Golf side view, headlight detail with headlight washer system

Head-up Display  

The head-up display shows vehicle-related information directly in the driver’s field of vision. The information is shown on a transparent display that extends behind the dash panel at the touch of a button. This allows the driver to read all relevant information without needing to take their eyes off the road.
The driver decides which information is displayed themselves. This may include current speed, traffic signs, speed limits, assist system activity, navigation instructions or warnings. Options can be selected in a menu in the infotainment system.


Image of information in the head-up display of a VW Tiguan Allspace

Heat-reflecting glass 

The heat-insulating, infrared-reflecting insulation glass creates a pleasant interior temperature. It prevents the interior from heating up when outside temperatures are high and promotes vehicle occupants’ wellbeing. When an air conditioning system is used, fuel consumption is also reduced, as less energy is required for cooling to the preferred temperature. This reduces costs.

VW with heat-reflecting glass outside a park

High-voltage power connection

German household sockets are fed with alternating current electricity with a voltage of 230 volts. However, three-phase connection with 400 volts are also possible and is often called “high-voltage power” or “three-phase alternating current”. It differs from the current from normal electrical sockets by having a higher voltage. The current rating of household electrical sockets is usually limited to 16 A with corresponding fuses.

Hill Descent Assist/Hill Start Assist

Hill Descent Assist helps with controlled downhill driving off-road with automatic and targeted braking interventions. It helps keep vehicle speed constant and make extreme inclines easier to handle.

Hill Start Assist can hold the driver’s brake pressure for a maximum of two seconds. When making a hill start, depending on the gradient and accelerator pedal position, it can automatically release the brake. This makes comfortable hill starts possible without prior rolling back.*

* within the system’s limitations

Two Volkswagen vehicles in the mountains

Humidity sensor  

In conjunction with the ‘Climatronic’s control algorithms, a special sensor system reduces window fogging and increases climate comfort with interior humidity management.
Based on data from the humidity and temperature sensor at the base of the interior mirror, the ‘Climatronic’ control unit calculates the air’s dew point temperature - i.e. the temperature at which moisture in the air would condense. A infrared sensor performs contactless measurement of heat radiation on the windscreen and thus the windscreen temperature. To prevent the window from fogging, the ‘Climatronic’ controls the volume of air at the windscreen and, when the compressor is switched on, the moisture content of the air in the vehicle interior. The relative humidity with respect to the interior temperature can also be brought to a comfortable level.

Image of the rear view mirror in the interior of a VW Polo

Hybrid drive  

A hybrid drive consists of a combination of two drive principles, such as a TSI and an electric motor. The hybrid concept offers benefits in terms of consumption and pollutant reduction, especially in city traffic. The hybrid technology includes two different kinds of drive: the full hybrid and plug-in hybrid.
The full hybrid generates its own electricity by acting as a generator when braking and charging the high-voltage battery.
The plug-in hybrid works the same way, with one difference: it allows the electric motor battery to be charged using an external power source.

Schematic diagram of the hybrid drive in a VW Golf
Fuel consumption Golf GTE, l/100 km: combined 1.8 - 1.6;
electricity consumption, kWh/100 km: combined 12.0 - 11.4; CO₂ emissions
combined, g/km: 40 - 36; efficiency class: A+.

Hybrid vehicles (HEV)

Hybrid Electric Vehicles are vehicles that combine at least two drive concepts: a combustion engine-based and electric motor-based drive. The term “hybrid” is ambiguous as hybrid vehicles are classified according to the level of electrification (micro, mild, full and plug-in hybrid). In general usage, the term “hybrid vehicle” is usually used to describe a full hybrid.

Hydraulic 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 the stopping distance. The system operates almost imperceptibly for the driver.

See also:
Electronic Stability Control

Image of HBA indicator lamp