Piezoelectricity in multi-layer actuators Modelling and analysis in two and three dimensions

Actuators are used in injectors for Common-Rail diesel engines. They should show large generative forces while their response time must be very short. Furthermore, the actuator should be controlled in a relatively simple way by an electric field. These properties can be achieved by using piezoelectric actuators, either as monolithic ceramic pieces or as multi-layer actuators (MLAs) [3] with individual layers and interdigitated electrodes, wired parallel. MLAs require lower voltage for the same amount of actuation in comparison with monolithic pieces. The fabrication of co-fired MLAs is very similar to that of ceramic capacitors and therefore the chances for large scale production at low cost are better than for stacked-disk-actuators.