Abstract: A method for controlling charging and discharging of a battery pack for an electric or hybrid vehicle to prevent overheating damage. Current flowing into or out of the battery pack is monitored, and root mean square (RMS) current is integrated over a time window and compared to a threshold to determine if power needs to be regulated in order to prevent damage to the cells in the battery pack. If the time-integrated RMS current exceeds the threshold, a closed-loop proportional-integral (PI) controller is activated to regulate power input or output. The controller will continue to regulate power until the time-integrated RMS current drops below the threshold. Various thresholds can be defined for different time windows. The gains used in the PI controller can also be adjusted to scale the amount of power regulation.

Abstract: A method and system for selectively using a voltage-based state of charge estimate in an overall state of charge calculation. Regions or bands of battery pack state of charge are established, where in some regions, open circuit voltage is known to be a good indicator of state of charge, and in other regions, open circuit voltage is known to be a poor indicator of state of charge due to a high sensitivity to measurement error. In regions or bands where voltage-based state of charge is expected to be accurate, the voltage-based state of charge estimate may be used to scale or adjust a current-based state of charge estimate, thus avoiding a continuous accumulation of error in the current-based estimate. In regions or bands where voltage-based state of charge is known to be prone to error, only current-based state of charge information is used.

Abstract: A method for controlling charging and discharging of a battery pack for an electric or hybrid vehicle to prevent overheating damage. Current flowing into or out of the battery pack is monitored, and root mean square (RMS) current is integrated over a time window and compared to a threshold to determine if power needs to be regulated in order to prevent damage to the cells in the battery pack. If the time-integrated RMS current exceeds the threshold, a closed-loop proportional-integral (PI) controller is activated to regulate power input or output. The controller will continue to regulate power until the time-integrated RMS current drops below the threshold. Various thresholds can be defined for different time windows. The gains used in the PI controller can also be adjusted to scale the amount of power regulation.

Abstract: An acoustic liner is made by placing a raw adhesive septum between a pair of opposite honeycomb cores, and curing the septum to integrally bond the cores thereto.

Abstract: An acoustic treatment for the air ducts of a gas turbine engine. The acoustic treatment generally includes a facesheet having a plurality of holes therein, a backplate spaced apart from the facesheet, and a plurality of interconnected cells between the facesheet and backplate. Each of the cells is defined by walls attached to the facesheet and the backplate, and at least some of the walls are formed of a porous material so that air is able to flow through the cells in a direction parallel to the facesheet and backplate.

Abstract: An actively controlled acoustic treatment panel for suppressing noise in a gas turbine engine nacelle including a backsheet formed by a planar matrix of adjacent individually controllable elements, where each of the controllable elements has a transducer and a honeycomb cell enclosing the transducer. A facesheet is also bonded to the controllable elements. A plurality of sensors are positioned within the acoustic treatment panel for sensing acoustic pressure of the noise propagated against the facesheet. A driver is provided for electrically driving each of the transducers to effect displacement thereof in a direction substantially perpendicular to the facesheet. Circuitry is also operatively connected to the pressure sensors and the driver for controlling velocity magnitude and phase of the transducers during displacement, wherein a resulting acoustic impedance at the facesheet achieves a desired acoustic impedance boundary condition at the nacelle.

Abstract: The Mach number M.sub.o of flow in the intake nozzle or bypass duct of a gas turbine aircraft engine is determined from the acoustic impedance of a Helmholtz resonator to an engine fan-stator sound source. Pressure measurements P.sub.1 (t) and P.sub.2 (t), made nonintrusively at the duct wall surface and resonator cavity bottom are subjected to Fourier analysis to give P.sub.1 (f) and P.sub.2 (f), and acoustic impedance for the flow is determined from a complex transfer function H.sub.12. Flow Mach number is then established using known acoustic impedance/Mach number correlation relationships or a stored look-up table. An alternative embodiment, utilizes a sound source mounted in the Helmholtz resonator bottom and determines Mach number by pressure measurements made at spaced locations on the resonator chamber wall.

Abstract: A flexible U-shaped channel is abutted against a surface to be measured, thereby forming an acoustic duct, with the surface forming one wall of the duct. An acoustic source injects sound waves into the duct traveling parallel with the surface in order to establish a standing acoustic wave. Measurements of acoustic pressure at several points allows one to compute k.sub.y, the acoustic wave number normal to the surface, and from k.sub.y to compute the acoustic impedance of the surface.

Abstract: An open-ended acoustic impedance tube is abutted against a material having a known acoustic impedance and a standing wave pattern is established in the tube. A first apparent impedance of the material is derived based on the standing wave pattern. A correction factor is computed based on the known impedance and the first apparent impedance. The open-ended impedance tube is then abutted against a sample material and a second apparent impedance is derived. The actual impedance of the sample is inferred from the second apparent impedance and the correction factor.