Caterpillar Inc.

L Glenn Waterfield

Glen F Forck

Ronald Dean Shinogle

Richard H Holtman

Clifford E Cotton, Iii

Jerry P Maushard

Dana Ray Coldren

Kurtis C Kelley

Christopher F Gallmeyer

Method of manufacturing a piezoelectric actuator. The method includes a pre-cure step in which the adhesive is heated to a temperature below the melting point of the adhesive. A stack is formed having a piezoelectric layer and at least one supporting layer with the pre-cured adhesive therebetween. The stack is then cured to form a bonded laminate. The temperature at which the pre-cure occurs allows for the pre-stress in the piezoelectric layer to be modified without changing the material of the supporting layer.

Method of manufacturing a multi-layered piezoelectric actuator

An electronically-controlled fuel injector includes a pressurized fluid chamber that communicates high pressure fluid to first and second pressure control chambers. A direct-operated check moves between closed and open positions in response to a difference in fluid pressure in the first and second pressure control chambers. A thermally pre-stressed bender actuator is used to operate a control valve that controls the fluid pressure in the first pressure control chamber to effectively control opening and closing of the check during portions of an injection sequence.

Electronically-controlled fuel injector

A pre-stressed piezoelectric actuator is comprised of a plurality of layers. The layers include at least one electrically-active ceramic layer, a reinforcing substrate, and a top layer. Preferably, the top layer is comprised of a copper material having at least one lead integrally formed therewith, the lead being available for attaching the device to a voltage source. The copper layer further has a plurality of apertures defined therein to compensate for the stiffness of the copper and to allow the copper layer to deform. The layers are bonded by a thermally-activated adhesive. When the layers and adhesive are heated and cooled, the higher coefficients of thermal expansion in the substrate and top layers stresses the ceramic and causes the device to cool into an arcuate shape.

Piezoelectric device

An electronically-controlled fuel injector includes a pressurized fluid chamber that communicates high pressure fluid to first and second pressure control chambers. A direct-operated check moves between closed and open positions in response to a difference in fluid pressure in the first and second pressure control chambers. A first thermally pre-stressed bender actuator is used to operate a control valve that controls fluid communication between the fluid chamber and a fluid source. A second thermally pre-stressed bender actuator is used to operate a control valve that controls the fluid pressure in the first pressure control chamber to effectively control opening and closing of the check during portions of an injection sequence.

A valve system having a valve operated by a piezoelectric device to control the flow of fluid through the valve system. Movement of the valve is controlled by a pre-stressed bender actuator that changes its shape by deforming in opposite axial directions in response to a control signal applied by an actuator control system. The valve system may comprise a common rail fuel injector, electrohydraulic actuator system, electronically-controlled fuel injector, gasoline port injector, fluid metering valve, relief valve, reducing valve, direct valve or direct-injection gasoline injector.

Piezoelectric valve system

Apparatuses and methods for controlling the temperature induced deformation of a piezoelectric device. A piezoelectric device receives an activation signal and displaces in a first direction for a first predetermined distance as a function of the activation signal. The piezoelectric device also displaces in a second direction as a function of a change in temperature of the piezoelectric device. A stop is located a second predetermined distance from the piezoelectric device. The stop prevents the displacement of the piezoelectric device in the second direction beyond a third predetermined distance. A charge redistributing device is coupled with the piezoelectric device. The charge redistributing device redistributes charge on the piezoelectric device due to the temperature change to relieve internal electric fields of the piezoelectric device due to temperature induced deformation of the piezoelectric device.

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Peoria, IL, United States of America

L Glenn Waterfield