Abstract: A system and method for operating a fuel cell stack of a fuel cell system in a vehicle when an error in cathode air flow rate is detected. The system and method include estimating a cathode air flow rate and detecting an error in the estimated cathode air flow rate. The system and method also include utilizing high frequency resistance measurements from a high frequency resistance sensor to control a relative humidity of the fuel cell stack when the error in the estimated cathode air flow rate has been detected.

Abstract: An apparatus and method to determine the relative humidity of a fuel cell system. A controller is cooperative with a first device and a second device to receive a valve signal and a high frequency resistance value. The controller controls the relative humidity of a fuel cell stack based on the estimation of the relative humidity of the fuel cell stack based on one or more algorithms. The controller modifies the relative humidity of the fuel cell stack through changes in the position of a valve based on at least one of the valve signal and the high frequency resistance value. In one form, the relative humidity of the fuel cell system is determined without the need of a humidity sensor.

Abstract: A system and method for determining if an RH sensor that measures the relative humidity of cathode inlet air provided to a fuel cell stack or an HFR circuit that measures stack water content is operating properly. The method provides the cathode inlet air through a WVT unit that increases the water content of the cathode inlet air. The method uses a water buffer model for determining the water content of the fuel cell stack based on inputs from a plurality of system components and revises a water transfer model using the HFR humidification signal or the RH signal to correct for WVT unit degradation. The method determines whether the RH sensor or the HFR circuit is operating properly, such as by determining if the HFR humidification signal is increasing at a rate that is faster than what the stack water content is able to increase.

Abstract: A system and method for operating a fuel cell stack of a fuel cell system in a vehicle when an error in cathode air flow rate is detected. The system and method include estimating a cathode air flow rate and detecting an error in the estimated cathode air flow rate. The system and method also include utilizing high frequency resistance measurements from a high frequency resistance sensor to control a relative humidity of the fuel cell stack when the error in the estimated cathode air flow rate has been detected.

Abstract: An apparatus and method to determine the relative humidity of a fuel cell system. A controller is cooperative with a first device and a second device to receive a valve signal and a high frequency resistance value. The controller controls the relative humidity of a fuel cell stack based on the estimation of the relative humidity of the fuel cell stack based on one or more algorithms. The controller modifies the relative humidity of the fuel cell stack through changes in the position of a valve based on at least one of the valve signal and the high frequency resistance value. In one form, the relative humidity of the fuel cell system is determined without the need of a humidity sensor.

Abstract: A system and method for determining if an RH sensor that measures the relative humidity of cathode inlet air provided to a fuel cell stack or an HFR circuit that measures stack water content is operating properly. The method provides the cathode inlet air through a WVT unit that increases the water content of the cathode inlet air. The method uses a water buffer model for determining the water content of the fuel cell stack based on inputs from a plurality of system components and revises a water transfer model using the HFR humidification signal or the RH signal to correct for WVT unit degradation. The method determines whether the RH sensor or the HFR circuit is operating properly, such as by determining if the HFR humidification signal is increasing at a rate that is faster than what the stack water content is able to increase.

Abstract: A system and method for determining whether there is a cross-over leak, or other failure, in a WVT unit that humidifies the cathode inlet airflow to a fuel cell stack in a fuel cell system. The fuel cell system includes an HFR circuit that determines the humidity level of the membranes in the fuel cell stack and an RH sensor that measures the relative humidity of the airflow to the cathode side of the fuel cell stack. The HFR humidity calculation is compared to RH measurements from the RH sensor, and if the difference between the two RH values is greater than a predetermined calibration value, then the system may determine that the WVT unit is failing and needs to be serviced or replaced.

Abstract: A system and method for determining whether there is a cross-over leak, or other failure, in a WVT unit that humidifies the cathode inlet airflow to a fuel cell stack in a fuel cell system. The fuel cell system includes an HFR circuit that determines the humidity level of the membranes in the fuel cell stack and an RH sensor that measures the relative humidity of the airflow to the cathode side of the fuel cell stack. The HFR humidity calculation is compared to RH measurements from the RH sensor, and if the difference between the two RH values is greater than a predetermined calibration value, then the system may determine that the WVT unit is failing and needs to be serviced or replaced.

Abstract: Systems and methods of a multiple dispensing system may include an image carrier, and may include a plurality of substantially aligned developing units positioned to develop image information on the image carrier. Each developing unit may include only one ink container and only one developer housing. The systems and method may also include a first dispensing system positioned upstream in a sheet feed direction of the plurality of substantially aligned developing units. The first dispensing system may include a first ink container and a first developer housing. The first developer housing may be configured to receive first imaging media from the first ink container and second imaging media from at least one other ink supply source.

Abstract: A printing system that receives an imaging media cartridge includes a rail and a dock to install the imaging media cartridge. The imaging media cartridge includes a housing that has pivots along an alignment axis substantially parallel to the rail. The imaging media cartridge further includes a roller that slides along the rail, the roller being disposed on the housing. The imaging media cartridge also includes a bracket disposed on the housing. To insert the bracket into the dock, the housing rotates on the pivots. To further adjust the position of the imaging media cartridge in the xerographic system, the housing rotates along at least one axis substantially orthogonal to the alignment axis. The rail includes a support beam and a flange. The roller includes at least a pair of wheel housings, each wheel housing having a pair of tandem wheels that glide along the rail. The tandem wheels face each other and glide along the flange and between the support beam.

Abstract: A transportable device, such as a cart, for transporting and elevating an imaging media cartridge into a press printer may include a base platform, first and second elevation members disposed thereon, a panel disposed between the first and second elevation members, and first and second elevator platforms. The panel may include a pair of opposite vertical faces along which the elevator platforms slide to mutually exchange elevations by vertically sliding the platforms in opposite directions. The device may be used for a method of transporting and elevating an imaging media cartridge into a press printer at an installation height above a floor. Additionally, the device may be used for a method of removing and storing an imaging media cartridge from a press printer at an installation height above the floor.

Abstract: A trickle collection system including a trickle port formed in a developer housing and communicating with the interior of the developer housing, and a trickle port housing communicating the trickle port with an external vacuum collection source. The trickle port may include an aperture having a variable cross-section, for controlling an amount of flow of trickle through the trickle port. The trickle collection system also may include an air infusion port communicating the interior of the trickle port housing with external air and providing infusion of an amount of external air into the trickle port housing sufficient to facilitate flow of trickle from the trickle port to the external vacuum collection system. An aperture of the air infusion port may be variable, such that the amount of air infusion may be varied in accordance with internal and/or external conditions.

Abstract: An apparatus for developing a latent image recorded on a movable imaging surface, including: a reservoir for storing a supply of developer material including toner particles, said reservoir including a developer material mixing and transport area; a donor member being arranged to receive toner particles from said reservoir and to deliver toner particles to the image surface at locations spaced apart from each other in the direction of movement of the imaging surface thereby to develop the latent image thereon; and a climate system, associated with said reservoir, for maintaining said supply of developer material at a predefined temperature, said climate system includes a cooling element for supplying air to said developer material mixing and transport area, and a heating element positioned in said developer material mixing and transport area, said heating element includes a first heat unit associated with heating an inboard area of said developer material mixing and transport area and a second heat unit assoc

Abstract: A hydraulic tensioner having an external rack member. The rack member has an extending member at its upper end that contacts wedges or grooves along the exterior of the piston to limit backdrive or backlash of the piston. The rack member has an end member at its lower end that is located in a groove in the tensioner housing. The rack member has a plurality of portions that are held together by a garter spring to form a single cylindrical piece.

Abstract: A hydraulic tensioner is designed for low cost and ease of manufacturing. A housing has a bore and a sleeve member received within the bore. A piston is slidably received within the sleeve member, forming a high pressure fluid chamber with the sleeve member. The housing can be constructed of inexpensive materials such as aluminum or plastic. The piston and sleeve member are constructed of drawn metal. The housing may be formed by injection molding. The sleeve member and other components of the tensioner may be assembled within the tensioner by inserting them into the mold during the injection molding process.