| 摘要 |
A turbocharger actuator and a method of calibrating the actuator is particularly applicable to a variable nozzle turbocharger (VNT). The actuator comprises an actuator housing having a diaphragm connected across it, a piston, a compression spring arranged to be generally centred in the actuator housing and to bias the piston and keep the diaphragm for calibrating a turbocharger. The actuator housing may be connected to a bracket using three rivets and the diaphragm may crimped to connect it to the actuator housing coated with elastomer bead to improve and control the crimping process. The shape of the piston is modified to reduce the overall length of the actuator. The bracket for attaching the actuator assembly to the variable nozzle turbocharger housing comprises a first planar portion having a plurality of rivet holes formed therein for connection to the actuator assembly, and at least one, preferably two, second portion(s) extending generally perpendicular to the first portion and having an elongate hole formed therein to receive a bolt to attach the bracket to the turbocharger housing, the elongate hole allowing a sliding movement of the actuator assembly relative to the turbocharger housing. The calibration method comprises applying a predetermined vacuum to the actuator to allow the actuator to take a calibrated position determined by gravity whilst keeping the pin crank in contact with the flow screw of the turbocharger and tightening the or each bolt, at a predetermined torque, to tighten the attachment of the actuator assembly to turbine housing. The actuator calibration is controlled as normal and if it is not correct hen the process is repeated using a different predetermined vacuum value.
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