Abstract:
A method for controlling dual independent camshaft phasers in an internal combustion engine. The method has three basic steps: a) first, determining if rate balancing between the two phasers is required; b) second, determining the optimal rate balancing commands; and c) third, applying the determined rate balancing commands to the appropriate phaser(s). In determining the rate balancing commands, there are three possible phaser options: the intake phaser requires priority; the exhaust phaser requires priority; or neither phaser requires priority. Lookup tables are stored in the engine controller for each option. When either phaser has priority, the other phaser is actuated after a delay based upon the position error of the priority phaser, generally at a lower phase rate. When neither phaser has priority, both phasers are actuated at a rate consistent with oil-delivery capabilities of the engine.
Abstract:
A device for injecting light from one of a first group of optical fibers into a corresponding one of a second group of optical fibers includes a holder for locating each of the fibers in the first and second groups, a clamp for securing fibers in the second group to the holder, and a depressor for laterally displacing each of the fibers in the second group, thus forming a bend in each of the fibers in the second group. The maximum curvature in the bend occurs where the fibers in the second group exit the clamp. Light is injected from fibers in the first group into corresponding fibers in the second group at the point of maximum curvature. An optical gel may be used to used to promote optical coupling between fibers in the first group and fibers in the second group. The optical fibers in the second group may include a lens for focusing the light to be injected. The device can function in reverse to extract light from fibers in the second group into fibers in the first group.
Abstract:
A focused optical input signal is applied to an optically absorbent wall portion of a supply nozzle 40 in a fluidic device to cause boundary layer separation of flow therein. The boundary layer separation turns the flow to achieve a desired output from the device.
Abstract:
A laser beam is focused to a spot on the surface of an object whose contour is to be measured. The spot is projected from the surface onto a detector by a reciprocating mirror which scans the spot across the detector. The detector produces two output signals consisting of sequential pulses at the frequency scan. The relative duration of these pulses or duty cycle reflects the change in contour dimension with respect to the scan centerline or mid point that corresponds to the base or zero dimension of the contour surface. The duty cycle is utilized to compute the change in contour dimension and to move the optics in such a way as to allow the spot to be continually scanned across the detector. The movement of the optics is made whenever there is a certain contour dimension change and by correlating the movement in the position of the optics and the instantaneous computed contour change reflected in the scan, the actual contour dimension is obtained.
Abstract:
A method for detecting a low-lift or zero-lift failure mode in a variable valve activation system of an internal combustion engine includes the steps of positioning a piezo-electric element that acts as a radio frequency transmitter relative to a lost motion spring of a two-mode variable valve activation lost motion device, subjecting the piezo-electric element to a compression load when a load from displacement of a lobe of a camshaft acts on the lost motion spring, broadcasting a radio frequency signal each time the piezo-electric element is subjected to the compression load, and evaluating the presence or absence of the broadcasted radio frequency signal in relation to an expected presence or absence of the radio frequency signal. The direct measurement of the mode of each two-mode device is both more reliable and more efficient in the use of engine controller resources compared to currently existing diagnostic methods.
Abstract:
An exemplary embodiment of the present invention includes an optical circulator. The circulator may have, for example, a first port, a second port, and a third port. The first port may be configured to introduce light into the optical circulator. The system may also include a tunable fiber filter Bragg grating connected to the second port of the circulator and a tunable dispersion-compensating fiber Bragg grating connected to the third port of the optical circulator. The tunable dispersion compensating fiber Bragg grating and the tunable fiber filter Bragg grating may be configured to be tuned by a single actuator. This tuning may be either compression or strain tuning.
Abstract:
A first optical fiber is coupled to a second optical fiber by ablating a portion of the cladding from the first and second optical fibers, thus exposing or nearly exposing the fibers' cores, bringing the ablated regions close together in the presence of an optical couplant, adjusting the alignment of the fibers so as to achieve a desired optical coupling ratio, and securing the fibers relative to each other. The ablation can be accomplished using a laser. The fibers can be secured mechanically or using adhesives. The finished coupler can be sleeved or otherwise encapsulated for physical protection. The technique can be applied to pairs of fiber ribbons, each having multiple optical fibers.
Abstract:
The movement of a predetermined zone of a surface of a vibrating object is measured by separating a laser beam having a predetermined coherence length into a probe beam and a reference beam. The reference beam is then delayed relative to the probe beam by a predetermined time interval sufficient for the probe beam to travel through a predetermined distance at least corresponding to the coherence length, before being combined with the probe beam to form a combination beam. The combination beam is then subdivided into a plurality of substantially equal component beams each of which is conducted along a separate path to a location spaced from the predetermined zone substantially by one-half of the distance traveled by light in the predetermined time interval between the above location and the predetermined zone. A predetermined portion of each component beam is reflected at the respective location back into the respective path, while the remainder of each component beam is directed to the predetermined zone for return therefrom at least predominantly back toward the respective location and into the respective path with attendant coherent interference of the returned probe beam part with the reflected reference beam part of the same component beam. The return light beam are demodulated to obtain an indication of the movement of the predetermined zone.
Abstract:
A system for measuring the surface contour of an object by tracking the image of a spot of radiation focused on the surface is disclosed. The radiation spot is imaged on a plurality of suitable detectors which are remote to the surface and connected electrically in parallel. Continuous data on the contour of the surface is provided even though irregularities on the surface interfere with the scattered radiation propagating along the line of sight to one of the detectors. This highly accurate system is servocontrolled and can be automated for recording, storing or displaying data.
Abstract:
The present invention relates to an apparatus and method for the encryption and decryption of optically transmitted data, and more particularly to the encryption and decryption of optical data transmitted and received using only optical components. Because only optical components are used, the encryption and decryption is independent of the data rate of the optical signal. The apparatus may include an encryption device that operates by receiving and combining both an unencrypted optical signal as well as a delayed optical signal that is based on the unencrypted optical signal. An optical delay may be configured in a number of different ways and may be used for delaying the unencrypted optical signal. The apparatus may further include a decryption device that receives and combines an encrypted optical signal as well as a delayed optical signal that is based on the encrypted optical signal. An optical delay may be configured in a number of different ways and may be used for delaying the encrypted optical signal. To properly work together, the apparatus and method require that the optical delay on the encryption side perfectly match the optical delay on the decryption side in both the length of delay and arrangement.