摘要:
A method and apparatus for direct-conversion transmission generates a first frequency signal that is non-harmonically related to a transmit frequency signal, divides the first frequency signal to obtain a mixing frequency signal, divides the first frequency signal to obtain an intermediate frequency reference signal, generates the transmit frequency signal by using the mixing frequency signal to downconvert the transmit frequency signal into an intermediate frequency feedback signal, and phase-locks the intermediate frequency feedback signal to the intermediate frequency reference signal. The transmit frequency signal may be phase modulated, and may serve as an input to a saturated-mode power amplifier that can be configured for corresponding amplitude modulation. Alternatively, the un-modulated transmit frequency signal serves as the carrier signal input to a quadrature modulator, which imparts I/Q modulations to it, thereby producing a modulated carrier signal for input to a linear power amplifier.
摘要:
A method and apparatus for direct-conversion transmission generates a first frequency signal that is non-harmonically related to a transmit frequency signal, divides the first frequency signal to obtain a mixing frequency signal, divides the first frequency signal to obtain an intermediate frequency reference signal, generates the transmit frequency signal by using the mixing frequency signal to downconvert the transmit frequency signal into an intermediate frequency feedback signal, and phase-locks the intermediate frequency feedback signal to the intermediate frequency reference signal. The transmit frequency signal may be phase modulated, and may serve as an input to a saturated-mode power amplifier that can be configured for corresponding amplitude modulation. Alternatively, the un-modulated transmit frequency signal serves as the carrier signal input to a quadrature modulator, which imparts I/Q modulations to it, thereby producing a modulated carrier signal for input to a linear power amplifier.
摘要:
A method for fault diagnosis in a fuel injection system having first and second fuel injectors. The method includes initiating a current flow in the first and second fuel injectors. Further, a rise duration of the current flow to reach a threshold level is measured. The method further includes comparing the rise duration and a preset duration. The fuel injection system is controlled based on the comparison.
摘要:
In an engine equipped with a common rail fuel injection system, the engine can sometimes experience an overspeed condition, and the pump may respond to this overspeed condition with self-actuation even in the absence of any control signal. In order to prevent an over pressurization condition, a liquid supply into a pumping chamber of the pump is limited during a retraction stroke of a pump plunger by energizing an electrical actuator coupled to a spill valve, to move the spill valve toward a closed position. The electrical actuator is de-energized during a pumping stroke of the pump plunger to allow the spill valve to more toward an open position. Liquid from the pumping chamber is discharged through the spill valve during the pumping stroke, but over pressurization is avoided by limiting the amount of liquid that can enter the pumping chamber during the retraction stroke.
摘要:
A common rail fuel system includes a common rail supplied by an inlet metered high pressure pump and fluidly connected to a plurality of zero-leak fuel injectors. An electronic controller controls pressure in the common rail predominantly responsive to a rail pressure error when outside of an overshoot avoidance condition corresponding to the error being less than a first threshold and a time rate of change of the error being greater than a second threshold. Pressure in the common rail is controlled predominantly responsive to the time rate of change of the error during the overshoot avoidance condition.
摘要:
An hermetic seal 10 for a linear rod 12 having a portion thereof projected axially through a port 20 defined in a wall for a pressure chamber 14 and supported thereby for omni-directional motion. The seal is characterized by a resilient, impervious, cylindrical body having a first section concentrically related to the shaft and integrally affixed thereto comprising a linear ordered array of annular flutes 22, a second section integrally affixed to the wall of the chamber and concentrically related to the port comprising a second linear ordered array of annular flutes 24, and a third section interposed between said first and second sections and integrally affixed thereto in coaxial alignment therewith comprising an annular ordered array of linear flutes 26 concentrically related to the shaft, whereby axial, angular, and pivotal motion of the rod is accommodated.
摘要:
A method for fault diagnosis in a fuel injection system having first and second fuel injectors. The method includes initiating a current flow in the first and second fuel injectors. Further, a rise duration of the current flow to reach a threshold level is measured. The method further includes comparing the rise duration and a preset duration. The fuel injection system is controlled based on the comparison.
摘要:
The disclosure describes an engine system having liquid and gaseous fuel systems, each of which injects fuel directly into an engine cylinder. A controller monitors and controls engine operation in a normal mode, during which the engine produces rated power, and in a limp-home mode, which is used when an abnormal operating condition of the gaseous fuel system is present. During limp-home mode operation, the engine uses more liquid fuel and less or no gaseous fuel relative to the normal mode, and produces power that is less than rated power.
摘要:
An apparatus and method for rotatably positioning a machine housing is disclosed. A pump produces pressurized fluid to a motor that responsively rotates the machine housing. A control valve regulates fluid flow from the pump to the motor. A position sensor detects the rotational position of the housing and responsively produces an actual position signal. A device produces a signal indicative of a desired rotational position of the housing. A controller compares the desired and actual position signals, responsively produces an error signal, multiplies the error signal by a variable gain value representative of the housing acceleration and delivers a control signal to the control valve to rotate the housing to the desired position.
摘要:
A common rail fuel system diagnostic algorithm is executed by an engine control and real time to detect and identify a faulty fuel system component. Rail pressure data is processed through a digital resonating filter having a resonance frequency corresponding to a fault signature. A peak magnitude and phase of the output from the digital resonating filter reveals a degradation level of a fuel injector, and a phase of the output identifies which fuel injector is faulted.