A piezoelectric injection system 15, eg for a
diesel engine, comprises a VDCpower
supply 24 for supplying a power circuit 17
provided with a DC-DC converter having
high-side and low-side drivers 20, 21
connected at a switching node 22, the
drivers being electrically connected to at
least a piezoelectric injector 16. The value
of an electric parameter representative of
the operation the injection system is
monitored and compared with a
predetermined reference parameter value,
and emergency means 32 are activated when the monitored parameter value exceeds
the respective reference value. The electric parameter may be the current flowing
through the piezoelectric actuator 19 and/or the low-side driver 21, sensed by current
sensor 30, or the voltage across the piezoelectric actuator. The emergency means 32
may interrupt the operation of the drivers 20, 21, discharge the piezoelectric injector or
disconnect the injector form the power circuit 17
