Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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. In other words, the autocorrelation and/or cross-correlation techniques may be used. 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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).