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: A piezoelectric actuated fuel injector is provided for use in conjunction with an internal combustion engine. The fuel injector includes a piezoelectric actuator for actuating an injector valve, and a hydraulic assembly for interfacing between the piezoelectric actuator and the injector valve, where the injector valve axially separates from a discharge outlet in response to longitudinal expansion of the piezoelectric actuator, thereby allowing fuel flow from the fuel injector.

Abstract: A method is provided for detecting injection events in a piezoelectric actuated fuel injector. The method comprises the steps of: (a) providing a piezoelectric element for actuating the injector valve; (b) applying a voltage to the piezoelectric element, thereby actuating the injector valve; and (c) monitoring at least one of the voltage or current associated with the piezoelectric element, wherein changes in voltage or current are indicative of injection events in the fuel injector.

Abstract: The invention relates to an injection valve (10) for the fuel injection in a internal combustion engine, in particular in a diesel engine. The injection valve (10) has a holder body (20) in which a first passage (30) is formed. At the holder body (20) a nozzle body (40) of an injection nozzle (16) is secured in which a second passage (54) is formed which is connected to the first passage (30) and which together with the latter forms a fuel infeed line for the injection nozzle (16). Moreover, a closure mechanism (60) is provided for the closing off of the injection nozzle (16). A sleeve (74) serves for the sealing off of the connection point between the first and the second passage (30, 54).

Abstract: A fuel injection system is provided for controlling fuel pressure in a common rail through the use of a piezoelectric actuated fuel injector. The fuel injection system includes at least one fuel injector having an axially extending fuel passage therein, a control chamber disposed in the injector, an injector valve axially movable within the fuel passage in accordance with a fuel pressure in the control chamber, and a piezoelectric actuator for actuating the control valve. The fuel injection system further includes a pressure sensor for determining a fuel pressure in the common rail, and a controller electrically connected to the pressure sensor and to the piezoelectric actuator of the fuel injector.

Abstract: A hydraulic lash adjuster is provided for interfacing between a piezoelectric element and a control valve in a piezoelectric actuated fuel injector. The hydraulic lash adjuster includes an inner plunger having an axial passage for storing a working fluid therein, and an outer body having a socket dimensioned to receive the inner plunger. The inner plunger is movably coupled into the socket of the outer body so as to form a working chamber between a bottom outer surface of the inner plunger and a bottom surface of the socket in the outer body. The hydraulic lash adjuster further includes a feed valve assembly disposed in the passage of the inner plunger for providing the working fluid from the passage to the working chamber, thereby minimizing the volume of the working chamber.

Abstract: A glow sensor which combines functions of a diesel engine glow plug with an ion sensor for sensing engine combustion initiation and characteristics includes a ceramic rod retained in a supporting ceramic sleeve carried by a metal shell mountable in an engine cylinder head. The ceramic rod includes a heating element in a glow tip at the inner end of the rod which, in use, extends into an engine combustion chamber or pre-chamber. A conductive material such as platinum or palladium is coated on the lower end of the glow tip and connected by a conductor with a source of electric voltage. In use, the voltage produces a current carried by electrons generated by ionization of the combustion chamber gases during combustion. The current varies with the degree of ionization and the amount of electrons generated during various phases of the combustion event. The resulting information is usable in controlling engine operation or evaluating its operation for test purposes.

Abstract: An electrically controlled hydraulic actuated fuel injector wherein the amount of return fuel flow is substantially reduced without adversely affecting injection valve operation. An improved control valve armature valve disk of faster acting construction is also included. In one embodiment, dual pressurizing passages of differing diameters provide lower total fuel flow to a control chamber than the outflow through a depressurizing passage controlled by a control valve. Upon full opening of the injection valve, all return fuel flow is supplied to the control chamber through the smaller pressurizing passage, thereby reducing the requirement for pressure fuel flow. Upon closing of the control valve, cutting off discharge through the depressurizing passage, both of the dual pressurizing passages help fill the control chamber to quickly close the injection valve.