In front of the sensor working principle is

In front of the sensor working principle is: normal driving , the torsion spring hammer , moving contacts set at TDC position , Crankshaft Sensor Replacement does not trigger signal to the central controller . When the car crash , the inertia to overcome the spring force and torque to produce movement , driven contacts rotation, so dynamic and static contact engagement In this case, the sensor to the central controller happen "on" signal, security sensors connected , so electronic controller sends electric detonators detonated belt pretensioners instruction , so that the seat belt tensioner to achieve security role.