Abstract: In one aspect, a fuel injector includes an injector body that defines a fuel inlet, a drain outlet and a nozzle outlet. A direct operated check valve is positioned in the injector body and includes a needle valve member with an opening hydraulic surface exposed to fluid pressure in a nozzle supply passage, and a closing hydraulic surface exposed to fluid pressure in a needle control chamber. The needle valve member is movable between a first position at which the nozzle supply passage is blocked to the nozzle outlet, and a second position at which the nozzle supply passage is open to the nozzle outlet. A needle control valve is positioned in the injector body and includes a control valve member movable between a first position at which the needle control chamber is fluidly connected to the drain outlet, and a second position at which the needle control chamber is fluidly blocked to the drain outlet.

Abstract: A reductant injector mount is provided. The reductant injector mount includes a mounting region configured to connect to an exhaust conduit. The reductant injector also includes a contoured region formed in the mounting region. The contoured region is configured to increase a velocity of an exhaust gas flow through the contoured region. The contoured region is also configured to reduce a recirculation of the exhaust gas flow through the contoured region. Further, the reductant injector mount includes a cut out portion provided on the contoured region. The cut out portion is configured to receive a reductant injector tip therethrough.

Abstract: In one aspect, a fuel injector includes an injector body that defines a fuel inlet, a drain outlet and a nozzle outlet. A direct operated check valve is positioned in the injector body and includes a needle valve member with an opening hydraulic surface exposed to fluid pressure in a nozzle supply passage, and a closing hydraulic surface exposed to fluid pressure in a needle control chamber. The needle valve member is movable between a first position at which the nozzle supply passage is blocked to the nozzle outlet, and a second position at which the nozzle supply passage is open to the nozzle outlet. A needle control valve is positioned in the injector body and includes a control valve member movable between a first position at which the needle control chamber is fluidly connected to the drain outlet, and a second position at which the needle control chamber is fluidly blocked to the drain outlet.

Abstract: In one aspect, a fuel injector includes an injector body that defines a fuel inlet, a drain outlet and a nozzle outlet. A direct operated check valve is positioned in the injector body and includes a needle valve member with an opening hydraulic surface exposed to fluid pressure in a nozzle supply passage, and a closing hydraulic surface exposed to fluid pressure in a needle control chamber. The needle valve member is movable between a first position at which the nozzle supply passage is blocked to the nozzle outlet, and a second position at which the nozzle supply passage is open to the nozzle outlet. A needle control valve is positioned in the injector body and includes a control valve member movable between a first position at which the needle control chamber is fluidly connected to the drain outlet, and a second position at which the needle control chamber is fluidly blocked to the drain outlet.

Abstract: A pressure relief valve includes a valve body having a valve seat fluidly positioned between an inlet and an outlet. A valve member is movable among a first position, a second position, and a third position. The valve member is in contact with the valve seat and fluidly blocks the inlet from the outlet at the first position. At the second position of the valve member, the inlet is fluidly connected to the outlet via a small flow area. The inlet is fluidly connected to the outlet via a large flow area when the valve member is at the third position. An electrical actuator is attached to the valve body and is operably coupled to move the valve member when energized. The valve member includes an opening hydraulic surface exposed to fluid pressure in the inlet when at the first position. A spring is operably positioned to bias the valve member toward the second position when the valve member is at the third position.

Abstract: In one aspect, a fuel injector includes an injector body that defines a fuel inlet, a drain outlet and a nozzle outlet. A direct operated check valve is positioned in the injector body and includes a needle valve member with an opening hydraulic surface exposed to fluid pressure in a nozzle supply passage, and a closing hydraulic surface exposed to fluid pressure in a needle control chamber. The needle valve member is movable between a first position at which the nozzle supply passage is blocked to the nozzle outlet, and a second position at which the nozzle supply passage is open to the nozzle outlet. A needle control valve is positioned in the injector body and includes a control valve member movable between a first position at which the needle control chamber is fluidly connected to the drain outlet, and a second position at which the needle control chamber is fluidly blocked to the drain outlet.

Abstract: A piezoelectrically actuated device includes a body, a valve disposed within the body and an actuator for the valve, the actuator including a casing coupled with the body and a piezoelectric element disposed within the casing The actuator further includes a multi-function spring applying a preloading force to the piezoelectric element. The multi-function spring includes a first segment having a piston configured to translate a motion of the piezoelectric element during operation of the actuator, a second segment having at least one flexural element and a third segment having a first set of threads. The first set of threads is engaged with a second set of threads of the actuator and maintains the second segment in a tension state which corresponds with the preloading force.

Abstract: A system for preloading piezoelectric actuators includes a fixture, a preloading mechanism configured to apply a mechanical force to a piezoelectric element supported by the fixture, and a sensor configured to sense an electrical property induced by the mechanical force in an electrical circuit having the piezoelectric element therein. A control device is coupled with the sensor and configured to generate a signal based on the sensed electrical property. A method of setting or testing preload includes applying a mechanical force to a piezoelectric element, and correlating an electrical property induced by the mechanical force with a magnitude of the mechanical force. Closed loop control allows preload to be set highly accurately.

Abstract: A pressure relief valve includes a valve body having a valve seat fluidly positioned between an inlet and an outlet. A valve member is movable among a first position, a second position, and a third position. The valve member is in contact with the valve seat and fluidly blocks the inlet from the outlet at the first position. At the second position of the valve member, the inlet is fluidly connected to the outlet via a small flow area. The inlet is fluidly connected to the outlet via a large flow area when the valve member is at the third position. An electrical actuator is attached to the valve body and is operably coupled to move the valve member when energized. The valve member includes an opening hydraulic surface exposed to fluid pressure in the inlet when at the first position. A spring is operably positioned to bias the valve member toward the second position when the valve member is at the third position.

Abstract: A system for preloading piezoelectric actuators includes a fixture, a preloading mechanism configured to apply a mechanical force to a piezoelectric element supported by the fixture, and a sensor configured to sense an electrical property induced by the mechanical force in an electrical circuit having the piezoelectric element therein. A control device is coupled with the sensor and configured to generate a signal based on the sensed electrical property. A method of setting or testing preload includes applying a mechanical force to a piezoelectric element, and correlating an electrical property induced by the mechanical force with a magnitude of the mechanical force. Closed loop control allows preload to be set highly accurately.

Abstract: A system for preloading piezoelectric actuators includes a fixture, a preloading mechanism configured to apply a mechanical force to a piezoelectric element supported by the fixture, and a sensor configured to sense an electrical property induced by the mechanical force in an electrical circuit having the piezoelectric element therein. A control device is coupled with the sensor and configured to generate a signal based on the sensed electrical property. A method of setting or testing preload includes applying a mechanical force to a piezoelectric element, and correlating an electrical property induced by the mechanical force with a magnitude of the mechanical force. Closed loop control allows preload to be set highly accurately.

Abstract: A fuel injector includes a piezoelectric actuator subassembly having a casing and a piezoelectric element disposed within the casing. The piezoelectric element has an operating temperature range and includes a thermally contractive material having a negative thermal expansion coefficient over a second temperature range overlapping with the operating temperature range. A preload control element is coupled with the piezoelectric element and includes a thermally expansive material having a positive thermal expansion coefficient over the second temperature range. The preload control element maintains a constant preload on the piezoelectric element over a wide temperature range to inhibit temperature induced variability in operation, and can axially lengthen in opposition to axial shortening of the piezoelectric element, responsive to a temperature increase.

Abstract: A fuel injector includes a piezoelectric actuator subassembly having a casing and a piezoelectric element disposed within the casing. The piezoelectric element has an operating temperature range and includes a thermally contractive material having a negative thermal expansion coefficient over a second temperature range overlapping with the operating temperature range. A preload control element is coupled with the piezoelectric element and includes a thermally expansive material having a positive thermal expansion coefficient over the second temperature range. The preload control element maintains a constant preload on the piezoelectric element over a wide temperature range to inhibit temperature induced variability in operation, and can axially lengthen in opposition to axial shortening of the piezoelectric element, responsive to a temperature increase.

Abstract: A system for preloading piezoelectric actuators includes a fixture, a preloading mechanism configured to apply a mechanical force to a piezoelectric element supported by the fixture, and a sensor configured to sense an electrical property induced by the mechanical force in an electrical circuit having the piezoelectric element therein. A control device is coupled with the sensor and configured to generate a signal based on the sensed electrical property. A method of setting or testing preload includes applying a mechanical force to a piezoelectric element, and correlating an electrical property induced by the mechanical force with a magnitude of the mechanical force. Closed loop control allows preload to be set highly accurately.

Abstract: A piezoelectrically actuated device includes a body, a valve disposed within the body and an actuator for the valve, the actuator including a casing coupled with the body and a piezoelectric element disposed within the casing. The actuator further includes a multi-function spring applying a preloading force to the piezoelectric element. The multi-function spring includes a first segment having a piston configured to translate a motion of the piezoelectric element during operation of the actuator, a second segment having at least one flexural element and a third segment having a first set of threads. The first set of threads is engaged with a second set of threads of the actuator and maintains the second segment in a tension state which corresponds with the preloading force.