Profiles: Comfort and safety in the rear

 

Rear airbag

Function

The rear airbag is specially designed for use on the rear seats. Its design allows better protection of rear passengers in a severe frontal collision, and its particularly gentle deployment takes the varied situations in the rear into account.

In detail

In the rear airbag, cylindrical tubes are inflated with compressed gas and unfold a wing-shaped framework. A large, tent-like airbag deploys between the two wings, and this is inflated by the surrounding air via specially patented valves in the skin. These valves are so designed that the air cannot escape when the rear passenger is immersed in the airbag. The comparatively small volume of the tubes allows rapid deployment of a relatively large airbag volume. This takes place with comparatively low force and a low risk of injury, as the tubular wings give way to obstacles. The airbag volume is sufficient to protect the seat belt wearing passenger against colliding with the front seats, and to reduce the loads acting on the head and neck vertebrae by up to 30 percent in a severe frontal impact.

The rear airbag, what accident research says

In frontal collisions, around 12 percent of rear passengers suffer head injuries, and around 10 percent injuries to the neck area, although they are wearing a seat belt. [10]

Sensors

Airbag sensors, seat occupancy recognition

What accident research says

In Germany the seat belt wearing quota in the front and rear is 97%[11]. Despite this high quota, there is still a great potential to reduce the number of fatalities and injuries in road traffic with more sustained use of seat belts. This is shown by a detailed accident analysis by UDV (accident research by insurance companies)[12]. It showed that 28 percent of all fatally injured and 12 percent of all severely injured car occupants were not wearing a seat belt or wearing it incorrectly. In this connection UDV calculated that at present, around 200 accident fatalities and 1500 cases of severe injury in Germany per year could be avoided if all occupants were wearing a correctly fastened seat belt at all times.

In the USA the seat belt wearing quota on the rear seats is 70 percent.[13], and 40 percent of fatally injured car occupants were not wearing a seat belt[14] In some EU countries the quotas are as low as 30 to 50 percent (Hungary, Portugal, Austria, Spain)[15].

 

 

Belt feeders in the rear

Function

The rear belt feeder moves to its extended position when the passenger has entered and closed the door. It returns to its operating position when the latch plate engages in the belt buckle.

In detail

When the door is closed, the belt feeder extends at shoulder level and offers the passenger the seat belt. It remains in this position until the passenger has fastened the belt, or returns to its rest position after around ten seconds. Activation while on the move is not possible. The rear belt feeder is a tangible convenience system, and a passive safety feature that encourages the wearing of a seat belt in the rear.

Sensors

Door contact, belt buckle status recognition, vehicle speed, vehicle status

 

Illuminated belt buckle

Function

An LED on the belt buckle lights up when the door is opened, inviting the passenger to fasten the seat belt. The illuminated belt buckle also makes it easier to find the buckle in the dark, and reminds the occupants to wear a seat belt even before they enter the vehicle.

In detail

A transparent ring around the outer contour of the belt buckle is lit up by a red LED when the rear door is opened. The light only goes out when the latch plate is inserted into the buckle.

Additional function

The light makes it easier to find the belt buckle in poor lighting conditions. The belt buckle also lights up after an accident to improve orientation.

Sensors

Door switch, belt buckle status recognition, vehicle status

 

Heated seat belt

Function

An intermediate layer with heating elements[16] is integrated into the seat belt, allowing rapid warming close to the body in cold ambient temperatures. The warming effect of the belt is intended to encourage occupants to take off winter jackets etc. before setting off, which reduces belt slack. This comfort function also encourages occupants to obey the law and wear the seat belt.

In detail

The heating elements can warm the approx. 48 mm wide belt from an ambient temperature of -10 °C to body temperature in less than four minutes. This is many times faster than seat heating. The temperature of the seat belt is thermostatically controlled. The belt heating is switched on together with the seat heating, and can be adjusted in three stages. The integrated heating warms the belt across its entire width. Even in cold ambient temperatures, the belt is brought to a pleasant temperature within a very short time. The temperature is controlled by sensors in the belt.

Additional function

The heatable seat belt ensures better thermal comfort, and also gives electrically powered vehicles the potential for more efficient interior climatisation.

Sensors

Belt buckle switch, temperature sensor on the belt

Belt buckle with USB socket

Function

A USB socket is integrated into the belt buckle. This enables mobile devices to be charged and connected when the seat belt is fastened. A possible further function could be the transfer of data (e.g. video or audio data) to the media system and media display.

In detail

A USB C socket is recessed into the belt buckle. A passenger connecting a device only has a power supply and a connection to the vehicle's media system if the seat belt is buckled. This feature therefore motivates passengers to wear their seat belt.

Additional function

The number of passengers also increases the need for mobile device connections, especially in the rear.

If a child seat is installed on a seat, the USB C socket can also be used to supply power for electrical functions of the child seat.

Sensors

Belt buckle switch

[10] Source: GIDAS 6/2018, all AIS levels: 1-6.

[11] Source: International Transport Forum, quoted here: https://de.wikipedia.org/wiki/Sicherheitsgurt#Anlegequoten

[12] https://udv.de/de/mensch/regelverstoesse/fahrzeug/insassenschutz/nutzen-des-sicherheitsgurtes

[13] https://apps.who.int/gho/data/view.main.51416

[14] https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/812465

[15] According to ETSC.

[16] A heating element consisting of thin wires conducts electricity.

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