Abstract: A fuel cell system that employs a two-position valve at the cathode exhaust gas output for controlling the pressure within the fuel cell stack to control the stack relative humidity. In one embodiment, the two-position valve is switchable between a fully open and a fully closed position, where the valve is opened when the fuel cell system is operating at a low operation temperature and the valve is closed when the fuel cell system is operating at a high operation temperature. A fixed restriction valve is provided in parallel with the two-position valve so that when the two-position valve is fully closed, the proper amount of pressure is provided at the cathode output. In another embodiment, the two-position valve employs sized leak paths so that when the two-position valve is in the closed position, the cathode exhaust gas can still flow through.

Abstract: A step tailgate and mounting hardware system is presented where a tailgate can swing down to a position in order to create an intermediate stepping area. The tailgate has a primary hinge that allows the tailgate to swing down from a first position, to a second position. The tailgate has a bracket system that allows the tailgate to swing down to a third position in order to create an intermediate stepping area. The tailgate can move away from the vehicle by an inner arm. When the end of the inner arm reaches the end of the inside swing the inner arm can swing down by the inner and outer swing arms to a point where the swing arms are perpendicular to the main and inner arms. When the tailgate is in the third position the tailgate is below the truck bed, creating a stepping surface.

Abstract: A shut-off valve that has particular application for opening and closing a compressed hydrogen storage tank. In one embodiment, the valve includes two valve sealing members where one side of one valve sealing member is on the high pressure side of the valve and an opposing side of the other valve sealing member is on the high pressure side of the valve. Therefore, the pressure applied to the two valve sealing members offset each other so that less force is required to open the valve against the high pressure. In another embodiment, one of the sealing members is replaced with a bellows.

Abstract: Mechanical systems having anti-stick mediums applied thereto are provided. In one aspect, exhaust gas recirculation (EGR) valve systems having anti-stick mediums applied thereto are also provided. The anti-stick medium can be applied to any contacting surface, such as but not limited to the valve surface and/or the valve seat surface. The anti-stick medium is intended to prevent the valve surface and the valve seat surface sticking or bonding together, especially with respect to the operation of cooled or cold side EGR systems. If any materials should stick to the anti-stick medium, a portion of the anti-stick medium will break away from the surface, allowing the surface and/or component to function normally. The anti-stick medium can include, without limitation, boron nitride coatings, boron nitride aerosols, boron nitride greases, thin dense chrome platings, perfluoroalkoxy, and combinations thereof.

Abstract: A variable force solenoid is described, wherein the solenoid has a relatively long stroke and a relatively low profile. The solenoid includes an armature with at least one tapered surface and a pole piece with at least one tapered surface. The armature and the pole piece may each be provided with multiple tapers on more than one surface thereof.

Abstract: A defect detection system for thermally imaging a structure that has been energized by sound energy. The system includes a transducer that couples a sound signal into the structure, where the sound signal induces acoustic chaos in the structure that causes defects in the structure to heat up. In one embodiment, the transducer is a broadband transducer. A thermal imaging camera images the structure when it is heated by the sound signal.

Abstract: A vehicle tire interrogation system for interrogating sensors embedded in a vehicle tire. The interrogation system both transmits and receives appropriate RF signals to and from the sensors. The system includes antennas operating at two separate frequency bands that have an input impedance at both frequency bands at 50 ohms, are horizontally polarized, and have a gain at a minimum of 2 dBi at the two frequency bands. The antennas may be printed dual band antennas, such as wideband tapered slot antennas, dual band printed dipoles with reflectors or Yagi-Uda array antennas. The antennas can be embedded in various support structures to protect both the antenna and the vehicle tires.

Abstract: A comb frequency generator that is tunable to vary the width of the pulses in the output signal and achieve a maximum power output at different harmonic frequencies. A wavefront compression device receives a sinusoidal input signal and provides wavefront compression to create a compressed signal having a series of periodic fast edges. A delay device receives the fast-edge compressed signal and delays the fast-edge signal to create a delayed fast-edge signal. A combining device receives the original fast-edge compressed signal and the delayed fast-edge compressed signal to generate an output signal including a series of pulses having a width determined by the delay of the delayed signal. In one embodiment, the delay device is a shorted transmission line stub having a length selectively set by a series of MEM devices. In another embodiment, the delay device is an NLTL variable time delay device that delays the fast-edge signal.