Sensor-tech Limited

Other

Sensorteck L.p.

Erik B Vigmostad

Robert D Klauber

Frederick P Sprague

Fred P Sprague

Joseph V Mandarino

A magnetostrictive stress and torque sensor using the component of the output signal in-phase with the drive voltage to monitor stress or torque. In some embodiments, it may use the quadrature or out-of-phase component, or some combination of the in-phase and out-of-phase components. Such phase component monitoring has several advantages over magnitude detection, including a response which is a more linear function of torque, and which is not subject to overmodulation problems.

Phase magnitude signal detector

A method and apparatus detects degradation in performance of an engine by comparing signals such as those obtained from magnetostrictive sensors which are related to, but not necessarily accurately correlated with, stress/strain states of a torque/load transmitting member. A first signal is obtained relating to the stress in the member produced by a first loading event or series of events, typically from the firings of a cylinder in an internal combustion engine. A second signal is obtained which relates to the stress in the member produced by a second loading event or series of events from the same or other cylinder in which the torque/load was intentionally inhibited. The first and second signals are then compared to detect degradation in output of the engine.

Engine degradation detector

A method and apparatus to detect variations in load by comparing signals related to, but not necessarily accurately correlated with, stress/strain states of a load transmitting member. In one embodiment, a first signal is obtained relating to the stress in the member produced by a first loading event or series of events. A second signal is obtained which relates to the stress in the member produced by a second loading event or series of events. The first and second signals are compared to detect non-constant loading. Each of the two signals may be a composite of other signals. A magnetostrictive sensor may preferably be used to obtain the signals relating to the stress in the load transmitting member. The load may be applied force, torque, stress, strain, or deflection. Applications comprise internal combustion engine and driveline torque variation diagnostics, brake pedals, and suspension systems.

Stress and load variation detector

A method and apparatus to detect variations in load by comparing signals related to, but not necessarily accurately correlated with, stress/strain states of a load transmitting member. In one embodiment, a first signal is obtained relating to the time rate of change of stress in the member produced by a first loading event or series of events. A second signal is obtained which relates to the time rate of change of stress in the member produced by a second loading event or series of events. The first and second signals are compared to detect significant variations in loading. Each of the two signals may be a composite of other signals. A magnetostrictive sensor may preferably be used to obtain the signals relating to the stress in the load transmitting member. The load may be applied force, torque, stress, strain, or deflection. In another embodiment, the time rate of change of a single segment of an analog signal related to, but not directly correlated with, stress is used to determine rapid changes in load. In yet another embodiment, a statistical value derived from a plurality of signals is used to determine variation in load. Applications comprise internal combustion engine and driveline torque variation diagnostics, brake pedals, and suspension systems.

Load variation detector

A system for determining the occurrence of a misfire in an internal combustion engine includes an oscillator, a phase detector coupled to receive an engine timing signal and the oscillating signal from the oscillator for producing an error signal functionally relating to phase difference between the signals. A loop filter is coupled to the phase detector for producing a tracking signal for producing the oscillating signal functionally related to the tracking signal. A phase error accumulator is coupled to receive the error signal and is operative to produce an output signal when the magnitude of at least one of the duration and magnitude of the error signal exceeds a predetermined value.

Engine misfire detector

Disclosed are a method and apparatus for minimizing or eliminating the effect of air gap variation on the output signal of a magnetostrictive stress/torque signal. An RLC drive circuit is utilized by choosing appropriate circuit parameters and drive frequency such that the flux reducing effect from increasing air gap due to increase in magnetic reluctance is offset by a flux increasing effect from a concomitant reduction in eddy currents. The invention is particularly suited to cross design magnetostrictive sensors and to automotive engine diagnostics applications such as misfire, knock, and roughness detection.

Magnetostrictive torque sensor air gap compensator

A device for monitoring both position and torque variations in a torque carrying member such as a shaft or flywheel functions by using a magnetostrictive torque sensor to monitor both torque variations and rotational position. The torque carrying member is structured with cutouts, protuberances, or material variations which cause the path reluctance for the flux produced by the magnetostrictive sensor to be different for different rotational positions of the shaft. This manifests as an output signal variation in the sensor which is dependent on position, and which can be used in conjunction with the magnetostrictively induced variations in signal to permit monitoring of both torque and position. The device is suitable for use with automotive engines and provides cost and space savings.

Position sensing with magnetostrictive stress sensor

Engine misfire, knock or roughness detection method and apparatus

A method and apparatus for comparing torsional stress/strain states of a power transmitting member of an internal combustion engine to detect an abnormal combustion condition, including misfire or roughness. A first signal is obtained relating to the torsional stress in the member produced by a first combustion event or series of events. A second signal is obtained which relates to the torsional stress in the member produced by a second combustion event or series of events. The first and second signals are compared to detect the abnormal combustion event in the operation of the engine. A magnetostrictive sensor may preferably be used to obtain the signals relating to the torsional stress in the power transmitting member, such as the engine crankshaft.

Engine misfire or roughness detection method and apparatus

Disclosed are a method and apparatus for comparing torsional stress/strain states of a power transmitting member of an internal combustion engine to detect an abnormal combustion condition, including misfire, knock or roughness. Statistical processing steps may be used to detect an abnormal combustion event including: calculating a mean and standard deviation for a set of signals related to the torsional stress induced in the power transmitting member, calculating a difference between a later signal and the mean, calculating a ratio of the difference to the standard deviation, and comparing the ratio to a threshold. The ratio so obtained from a given cylinder may further be compared with one or more other such ratios from other cylinders. A magnetostrictive sensor may preferably be used to obtain the signals relating to the torsional stress in the power transmitting member, such as the engine crankshaft. In addition, the magnetostrictive sensor may include windings to cancel induced electromagnetic interference signals.

Engine misfire, knock of roughness detection method and apparatus

A noncontacting method for sensing stress and torque based on the principle of magnetostriction comprises inducing a magnetic flux in a shaft (20) via such means as a single core/coil(58/60) placed close to the shaft (20) which detects torque by means of voltage or current changes in the coil (60). Another embodiment comprises two single core/coils (58/60 and 59/61) and signal processing circuitry which produces a signal minimally affected by material property inhomogeneities. An additional embodiment employs a plurality of sensors (66A/66B) strategically located around the shaft (20) to eliminate spurious signals which are due to bending stress and shaft misalignment.

Minimal structure magnetostrictive stress and torque sensor

A noncontacting method for sensing torque based on the principle of magnetostriction comprises inducing a primary magnetic flux in a shaft (20) via such means as a primary excitation core/coil (30/32), utilizing a secondary core/coil (34/36), and an auxiliary core/coil (48/50), and dividing a secondary signal obtained from the secondary core/coil (34/36) by a signal obtained from the auxiliary core/coil (48/50) to obtain a torque dependent signal. Signal dependence on RPM, temperature, inhomogeneity of shaft permeability magnitude, and air gap is thereby minimized. Another embodiment employs a plurality of sensors (66A/66B) strategically located around the shaft (20) to eliminate spurious signals which are due to bending stress and shaft misalignment.

Signal dividing magnetostrictive torque sensor

A noncontacting method for sensing torque based on the principle of magnetostriction comprises inducing a primary magnetic flux in a shaft (20) via such means as a primary excitation core/coil(30/32), keeping primary path flux amplitude constant via such means as an auxiliary core/coil (48/50) and appropriate feedback circuitry, and obtaining a torque dependent signal which is a function of a secondary flux via such means as a secondary core/coil(34/36). Signal dependence on RPM, temperature, and material property inhomogeneities is eliminated or minimized, instantaneous torque measurement is possible, and mass production is made feasible. A second embodiment utilizes modified signal processing circuitry to eliminate spurious signal components. A third embodiment comprises a single core/coil(58/60) placed close to a shaft (20) which detects torque by means of voltage or current changes in the coil (60). Embodiment four comprises two single core/coils(58/60 and 59/61) such as those of embodiment three and signal processing circuitry which produces a signal minimally affected by RPM, temperature, and material property inhomogeneities. A fifth embodiment employs a plurality of sensors (66A/66B) strategically located around the shaft (20) to eliminate spurious signals which are due to bending stress and shaft misalignment.

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Fairfield, IA, United States of America

Erik B Vigmostad