Front Seatbelt Tensioners
On the E65, pyrotechnic seatbelt tensioners are used for the driver and passenger seat. The principle of the seatbelt lock tensioner is the same as that used in the E38/E39.
The seatbelt tensioner has the task in the event of a crash to remove or reduce any belt slack in the pelvic and shoulder region.
The belt slack comes about mainly due to the motion of the occupants or due to clothing, (especially when heavy clothing are worn in the winter).
This ensures that the occupant is restrained firmly on the seat and prevents "submarining", slipping under a slack seatbelt.
There is also earlier restraint and thus earlier binding to the vehicle. The seatbelt tensioner forms a unit with the seatbelt buckle. It consists of an ignition stage, generator, plunger and cable. The belt buckle switch is integrated in the seatbelt buckle.
In the event of a crash of sufficient severity, the gas generator is ignited. The gas spreads and shifts the plunger in the tensioning pipe. The cable connected to the plunger then pulls the seatbelt buckle downward and the belt slack from the belt system.
On the E65, there are the following technical changes. The ignition stage is no longer directly connected onto the gas generator but rather the connection comes out on a cable together with the belt buckle switch cable and is plugged under the seat. If the seatbelt tensioner needs replacing, the seat does not have to be removed.