Abstract: A method of controlling a solenoid actuated fuel injector including applying a activation (pulse) profile to the solenoid, the activation profile including a hold phase, the hold phase including one or more hold pulses, and including a Pulse Width Modulation (PWM) scheme. The method includes determining the time period between the first hold pulse and the end of the previous pulse in the PWM scheme and increasing the energy of the activation profile if the time period is above a threshold.

Abstract: A method is provided for determining the velocity of a pintle assembly in a solenoid fuel injector during a closing stroke of the pintle assembly, such that a braking step is performed during the closing stroke, which includes operating an injector driver with a current regulator to establish a braking current in the solenoid coil. The velocity of the pintle assembly is derived from the duty-cycle of the current regulator during the braking step. A method of operating a solenoid fuel injector, in particular for gaseous fuel, using the so-determined pintle velocity is also provided.

Abstract: A method is provided for determining the velocity of a pintle assembly in a solenoid fuel injector during a closing stroke of the pintle assembly, such that a braking step is performed during the closing stroke, which includes operating an injector driver with a current regulator to establish a braking current in the solenoid coil. The velocity of the pintle assembly is derived from the duty-cycle of the current regulator during the braking step. A method of operating a solenoid fuel injector, in particular for gaseous fuel, using the so-determined pintle velocity is also provided.

Abstract: A catalytic hydrocarbon reformer comprising a catalyst concentrically disposed within a reformer tube surrounded by an annular flow space for air entering a fuel-air mixing zone ahead of the catalyst. The catalyst is sustained by minimal insulative mounting material so that most of the side of the catalyst is exposed for radial radiative heat transfer to the reformer tube for cooling by air in the annular flow space. The forward portion of the mounting material preferably is formed of a thermally-conductive material to provide radial conductive cooling of the entry of the catalyst to prevent overheating during catalysis. The incoming air flow is protected from heat exchange with hot reformate exiting the catalyst, allowing for convective cooling of the catalyst side and greater cooling of the catalyst face, thus increasing the working life of the catalyst while providing for rapid startup of the reformer and associated fuel cell system.

Abstract: A catalytic reformer assembly and methods of operation, including fast start-up, are provided. The reformer assembly includes an electrically-conductive metallic vaporizer having a very high surface area. At start-up of the reformer, electric current is passed through the vaporizer to heat the material by resistance heating, providing a high-temperature, high-surface area environment for fuel vaporization. Preferably, the electric current is started a few seconds before starting fuel flow. The fuel is sprayed either onto or through the heated vaporizer, preferably before the fuel is mixed with incoming air to minimize convective cooling by the air and to reduce the pressure drop in the fuel flow. As the reformer warms up, energy from the reforming process heats the vaporizer via radiation and/or conduction such that electric power is needed only during the start-up phase. A control circuit regulates the amount and duration of electric power supplied to the vaporizer.

Abstract: In one embodiment, a fuel reformer can comprise: a mixing zone capable of mixing a fuel and an oxidant to form a fuel mixture and a reforming zone disposed downstream of the mixing zone. The reforming zone comprises a primary substrate and a secondary substrate. The primary substrate is disposed upstream of the secondary substrate and has a primary thermal mass that is greater than a secondary thermal mass of the secondary substrate. One embodiment of a method for operating a fuel reformer can comprise: mixing an oxidant and a fuel to form a fuel mixture, combusting the fuel mixture, heating the secondary substrate above its light-off temperature, changing an air to fuel ratio of the fuel mixture to a reforming mixture, producing an exotherm and a reformate at the secondary substrate, heating a primary substrate with the exotherm to above its light-off temperature, and producing a reformate.

Abstract: A catalytic hydrocarbon reformer comprising a catalyst concentrically disposed within a reformer tube surrounded by an annular flow space for air entering a fuel-air mixing zone ahead of the catalyst. The catalyst is sustained by minimal insulative mounting material so that most of the side of the catalyst is exposed for radial radiative heat transfer to the reformer tube for cooling by air in the annular flow space. The forward portion of the mounting material preferably is formed of a thermally-conductive material to provide radial conductive cooling of the entry of the catalyst to prevent overheating during catalysis. The incoming air flow is protected from heat exchange with hot reformate exiting the catalyst, allowing for convective cooling of the catalyst side and greater cooling of the catalyst face, thus increasing the working life of the catalyst while providing for rapid startup of the reformer and associated fuel cell system.

Abstract: A catalytic reformer assembly and methods of operation, including fast start-up, are provided. The reformer assembly includes an electrically-conductive metallic vaporizer having a very high surface area. At start-up of the reformer, electric current is passed through the vaporizer to heat the material by resistance heating, providing a high-temperature, high-surface area environment for fuel vaporization. Preferably, the electric current is started a few seconds before starting fuel flow. The fuel is sprayed either onto or through the heated vaporizer, preferably before the fuel is mixed with incoming air to minimize convective cooling by the air and to reduce the pressure drop in the fuel flow. As the reformer warms up, energy from the reforming process heats the vaporizer via radiation and/or conduction such that electric power is needed only during the start-up phase. A control circuit regulates the amount and duration of electric power supplied to the vaporizer.

Abstract: In one embodiment, a fuel reformer can comprise: a mixing zone capable of mixing a fuel and an oxidant to form a fuel mixture and a reforming zone disposed downstream of the mixing zone. The reforming zone comprises a primary substrate and a secondary substrate. The primary substrate is disposed upstream of the secondary substrate and has a primary thermal mass that is greater than a secondary thermal mass of the secondary substrate. One embodiment of a method for operating a fuel reformer can comprise: mixing an oxidant and a fuel to form a fuel mixture, combusting the fuel mixture, heating the secondary substrate above its light-off temperature, changing an air to fuel ratio of the fuel mixture to a reforming mixture, producing an exotherm and a reformate at the secondary substrate, heating a primary substrate with the exotherm to above its light-off temperature, and producing a reformate.