Patent ID: 8596180

Claim:
A method for operating a pyrotechnic actuator to lift an active bonnet of a vehicle a plurality of times without having to perform maintenance on the pyrotechnic actuator, the pyrotechnic actuator comprising: a cylinder having an inlet opening, two end regions and a central region located between the two end regions, wherein an inside width of the cylinder in the central region is greater than an inside width of at least one of the end regions, a first chamber and a second chamber that are separated by the central region; a carrier having a plurality of gas generators coupled to the inlet opening; and a piston that is configured to be displaced through the central region, the method comprising: igniting a first gas generator to generate propellant gas that first charges the first chamber to displace the piston within the cylinder and then, after the piston has been displaced into the central region, charges the second chamber with the propellant gas by passing the propellant gas through the central region and around the piston into the second chamber, and to lift the active bonnet a first time.