What Are the Types of Seatbelt Pretensioners?
2 Answers
Seatbelt pretensioner types include ELR combination, ELR, and ALR. What is a seatbelt pretensioner: The front passenger seat of this vehicle is equipped with seatbelt pretensioners. Although the seatbelt pretensioners are not visible, they are integral components of the seatbelt system. If the threshold conditions for pretensioner activation are met, they help tighten the seatbelt during the initial stages of moderate to severe frontal collisions, near-frontal collisions, or rear-end collisions. Additionally, for vehicles equipped with side-impact airbags and roof curtain airbags, seatbelt pretensioners can assist in tightening the seatbelt during side collisions or rollover accidents. Function of seatbelt pretensioners: The working principle of a pretensioning force-limiting seatbelt involves the airbag ECU sending a pretensioning ignition signal. The gunpowder inside the pretensioner burns, generating high-pressure gas as the curling power to eliminate the gap between the seatbelt and the occupant. Currently, pretensioning force-limiting seatbelts are widely used in mid-to-high-end vehicle models.
I'm particularly focused on the construction of safety systems. Seatbelt pretensioners mainly come in three common types. The most prevalent is the pyrotechnic pretensioner, which operates via a small gas generator and metal cable, instantly tightening the seatbelt when the pyrotechnic charge ignites during a collision. Another type is the motor-driven pretensioner, more commonly seen in high-end electric vehicles, which uses sensors to anticipate collision risks and tighten the belt in advance. Some older commercial vehicles may be equipped with mechanical pretensioners, triggered by inertial centrifugal force to activate the locking mechanism. However, regardless of the type, all must respond within milliseconds after the sensors detect a collision, working in tandem with load limiters to secure the body without causing rib injuries.
