Abstract: A piezoelectric actuator arrangement (30) for use in a fuel injector (2), the actuator arrangement (30) comprising a stack (36) of one or more piezoelectric elements for receipt with an fluid chamber (12) of the injector (2), electrode means for generating an electric field within the stack (36), in use, and an electrical connector arrangement (42) for electrically connecting the electrode means to an external power supply, in use. The connector arrangement (42) comprises a first portion (60) in the form of a, base member, and a second portion (62) in the form of a body member, that are mutually arranged to form an articulated joint so as to provide the first portion (60) with at least one degree of freedom relative” to the second portion (62).

Abstract: A piezoelectric actuator comprises a stack of piezoelectric elements formed from piezoelectric material, a plurality of positive internal electrodes interdigitated with a plurality of negative internal electrodes to define active regions of the piezoelectric material which are responsive to a voltage being applied across the internal electrodes, in use. The active regions are responsive to voltage applied across the internal electrodes, in use. The piezoelectric actuator also comprises an external positive electrode for connection to the positive internal electrodes and an external negative electrode for connection to the negative internal electrodes.

Abstract: A piezoelectric actuator arrangement (30) for use in a fuel injector (2), the actuator arrangement (30) comprising a stack (36) of one or more piezoelectric elements for receipt with an fluid chamber (12) of the injector (2), electrode means for generating an electric field within the stack (36), in use, and an electrical connector arrangement (42) for electrically connecting the electrode means to an external power supply, in use. The connector arrangement (42) comprises a first portion (60) in the form of a, base member, and a second portion (62) in the form of a body member, that are mutually arranged to form an articulated joint so as to provide the first portion (60) with at least one degree of freedom relative” to the second portion (62).

Abstract: An electrical connector arrangement for a piezoelectric actuator (10) having a stack (26) of one or more piezoelectric elements, the electrical connector arrangement including positive and negative terminals (30, 32) for connection with distribution electrodes (44a, 44b) of the piezoelectric stack (26). Each of the positive and negative terminals (30, 32) has a lower end face (30d, 32d) which locates adjacent to an upper end face of the stack (26), in use, and a radially outer contact face (30e, 32e) for contact with the distribution electrodes (44a, 44b). The terminals (30, 32) also connect with an external voltage supply, in use. A block (30c, 32c) of each terminal (30, 32) defines the radially outer contact face (30e, 32e) for the stack distribution electrodes (44a, 44b) and thus provides a robust terminal structure.

Abstract: An actuator includes a piezoelectric stack within a housing that applies a compressive load to the stack. The housing may include a cylindrical tube closed at one end and may seal the stack against fluid pressure. The housing may be shorter than the length of the piezoelectric stack and may include resilient means for inducing elastic strain in the stack. The resilient means may include one or more slots extending around the circumference of the housing and/or a corrugated region of the housing to form a tension spring at a lower end of the housing. The tension spring may then serve to draw the stack into compression. The stack may include a plurality of layers of piezoelectric or piezoceramic material interspersed with a plurality of layers of electrically conductive material and connecting means for connecting the layers to a source of electrical power.

Abstract: An actuator includes a piezoelectric stack within a housing that applies a compressive load to the stack. The housing may include a cylindrical tube closed at one end and may seal the stack against fluid pressure. The housing may be shorter than the length of the piezoelectric stack and may include resilient means for inducing elastic strain in the stack. The resilient means may include one or more slots extending around the circumference of the housing and/or a corrugated region of the housing to form a tension spring at a lower end of the housing. The tension spring may then serve to draw the stack into compression. The stack may include a plurality of layers of piezoelectric or piezoceramic material interspersed with a plurality of layers of electrically conductive material and connecting means for connecting the layers to a source of electrical power.

Abstract: An electrical connector arrangement for a piezoelectric actuator (10) having a stack (26) of one or more piezoelectric elements, the electrical connector arrangement including positive and negative terminals (30, 32) for connection with distribution electrodes (44a, 44b) of the piezoelectric stack (26). Each of the positive and negative terminals (30, 32) has a lower end face (30d, 32d) which locates adjacent to an upper end face of the stack (26), in use, and a radially outer contact face (30e, 32e) for contact with the distribution electrodes (44a, 44b). The terminals (30, 32) also connect with an external voltage supply, in use. A block (30c, 32c) of each terminal (30, 32) defines the radially outer contact face (30e, 32e) for the stack distribution electrodes (44a, 44b) and thus provides a robust terminal structure.

Abstract: The invention relates to a fuel injection apparatus, in particular for diesel engines, comprising at least one injection nozzle which is connected to a fuel pressure line and which has a nozzle element which can be actuated through a control unit for the opening and the closing of the injection nozzle, with the control unit comprising a piston which is displaceably journalled in a control passage, which is coupled at its one end to the nozzle element and which bounds with its other end together with a plug which is arranged in the control passage a pressure chamber which can be connected up to the fuel pressure line via a supply passage and which communicates with an outflow passage, with it being possible to vary the pressure in the pressure chamber through the release or the interruption of the flow through the outflow passage for the actuation of the nozzle element when the pressure chamber is connected via the supply passage to the fuel pressure line, and with it being possible to influence the flow throu