Abstract: A fuel injector for an engine is disclosed. The fuel injector has a plunger disposed within a bore, a nozzle member, a valve needle, a check valve, a spill valve, and a controller. The check valve is movable between a first position at which the valve needle is communicated with the bore, and a second position at which the valve needle is fluidly communicated with a drain. The spill valve is movable between a first position at which fuel flows from the bore to the drain, and a second position at which the fuel from the bore is blocked. The controller moves the spill valve toward its second position and the check valve toward its second position during a downward displacing movement of the plunger. The controller detects an unsuccessful movement of the check valve to the second position, and prematurely halts the current injection event in response to the detection.

Abstract: A method of determining and regulating a mass flow rate exhaust gases recirculated into an engine is disclosed. The method may comprise directing the exhaust gases through a venturi and sensing a differential exhaust pressure across the venturi. The method may further include sensing an absolute exhaust pressure at the venturi, and sensing a temperature of the exhaust gases. The method may further include determining the mass flow rate of the exhaust based on the sensed differential fluid pressure, absolute fluid pressure, and temperature.

Abstract: A fuel injector for an engine is disclosed. The fuel injector has a plunger disposed within a bore, a nozzle member, a valve needle, a check valve, a spill valve, and a controller. The check valve is movable between a first position at which the valve needle is communicated with the bore, and a second position at which the valve needle is fluidly communicated with a drain. The spill valve is movable between a first position at which fuel flows from the bore to the drain, and a second position at which the fuel from the bore is blocked. The controller moves the spill valve toward its second position and the check valve toward its second position during a downward displacing movement of the plunger. The controller detects an unsuccessful movement of the check valve to the second position, and prematurely halts the current injection event in response to the detection.

Abstract: Apparatus and methods for exciting a piezoelectric device. A control device receives a first control signal excites the piezoelectric device at about at least one predetermined electrical resonant frequency of the piezoelectric device as a function of the first control signal.

Abstract: A control system for determining and controlling position and velocity of a valve member relative to a valve contact surface in a valve system preferably having an actuator comprised of a piezoelectric device. The control system includes an actuator control circuit for applying a control signal to the actuator to move the member relative to the contact surface. The control system further includes a seat detection circuit for determining when the member impacts the contact surface. The control system further includes a velocity control circuit which utilizes the output of the seat detection circuit from the previous actuation cycle to control the position and velocity of the member relative to the contact surface in the subsequent actuation cycle.

Abstract: 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.

Abstract: A control system for determining and controlling position and velocity of a valve member relative to a valve contact surface in a valve system preferably having an actuator comprised of a piezoelectric device. The control system includes an actuator control circuit for applying a control signal to the actuator to move the member relative to the contact surface. The control system further includes a seat detection circuit for determining when the member impacts the contact surface. The control system further includes a velocity control circuit which utilizes the output of the seat detection circuit from the previous actuation cycle to control the position and velocity of the member relative to the contact surface in the subsequent actuation cycle.

Abstract: The present invention provides methods and apparatus for controlling an electric field across a piezoelectric device. A temperature determining device transmits a temperature signal indicative of a temperature of the piezoelectric device. A control device receives the temperature signal and a first control signal indicative of a desired displacement of the piezoelectric device. The control device transmits a second control signal to the piezoelectric device as a function of the temperature signal and the control signal. The second control signal creates the electric field across the piezoelectric device, when the temperature of the piezoelectric device is below a predetermined threshold, having a magnitude above a normal operating range for the piezoelectric device.

Abstract: 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.

Abstract: Apparatus and methods for exciting a piezoelectric device. A control device receives a first control signal excites the piezoelectric device at about at least one predetermined electrical resonant frequency of the piezoelectric device as a function of the first control signal.

Abstract: The present invention provides methods and apparatus for controlling an electric field across a piezoelectric device. A temperature determining device transmits a temperature signal indicative of a temperature of the piezoelectric device. A control device receives the temperature signal and a first control signal indicative of a desired displacement of the piezoelectric device. The control device transmits a second control signal to the piezoelectric device as a function of the temperature signal and the control signal. The second control signal creates the electric field across the piezoelectric device, when the temperature of the piezoelectric device is below a predetermined threshold, having a magnitude above a normal operating range for the piezoelectric device.

Abstract: A control system for temperature compensating a piezoelectric device. The control system includes a temperature compensating circuit that is operable to receive a control signal corresponding to a desired position of the piezoelectric device and compensate the control signal in response to an estimated temperature proximate the piezoelectric device. A piezoelectric device control circuit is operable to receive the temperature compensated control signal and generate a control signal that is adapted to drive the piezoelectric device to the desired position. The temperature proximate the piezoelectric device may be estimated from an estimated ferroelectric polarization of the piezoelectric device or from a temperature sensor.

Abstract: A control system for temperature compensating a piezoelectric device. The control system includes a temperature compensating circuit that is operable to receive a control signal corresponding to a desired position of the piezoelectric device and compensate the control signal in response to an estimated temperature proximate the piezoelectric device. A piezoelectric device control circuit is operable to receive the temperature compensated control signal and generate a control signal that is adapted to drive the piezoelectric device to the desired position. The temperature proximate the piezoelectric device may be estimated from an estimated ferroelectric polarization of the piezoelectric device or from a temperature sensor.

Abstract: A system for controlling the operation of a piezoelectric device including a control system operable to generate a first control signal representing a desired charge on the piezoelectric device and corresponding to a desired position of a piezoelectric device. The control system further includes a charge control circuit responsive to the first control signal for providing a charge control signal to a device control circuit. The device control circuit provides a command signal that causes the piezoelectric device to move to the desired position.

Abstract: A control system for controlling position and velocity of a piezoelectric device. The control system includes a position control circuit that is operable to receive a control signal corresponding to a desired position of the piezoelectric device, and to compare the control signal to an estimated position of the piezoelectric device. The position control circuit generates a position error control signal that is adapted to drive the piezoelectric device to the desired position. The control system may further include a velocity control circuit that is operable to receive the position error control signal and generate a control signal that is adapted to drive the piezoelectric device to the desired position and at the desired velocity according to a predetermined velocity profile.

Abstract: An AC glow plug system is provided that includes a static converter for DC to AC conversion. Control techniques include varying the converter duty cycle according to glow plug temperature and other parameters such as engine air or coolant temperatures for smooth running as well as for prolonging glow plug life. Control is also varied according to fuel system characteristics and fuel composition.