Abstract:
A fuel injector wherein a cylindrical surface supports an electrical heating structure covering 360° or almost 360° of the surface for heating fuel. The structure comprises a first dielectric layer adhered to the surface; a thick film resistance heating element; a second dielectric layer; spaced-apart first and second conductor pads, wherein the first conductor pad is disposed in contact with a dielectric layer and a first end of the heating element, and wherein the second conductor pad is disposed in contact with a dielectric layer and a second end of the heating element. Another dielectric layer may be disposed over the preceding layers and the first and second conductor pads and having first and second windows formed therein for access to the first and second conductor pads. The resistance heating element may selectively be trimmed by overprinting in a pattern one or more times to improve the uniformity of heating.
Abstract:
A method for controlling electrical power applied to a fuel heater includes applying power to the heater, determining a value for an electrical parameter that varies as a function of the temperature of the heater, and determining a value representative of the time rate of change of the electrical parameter. The method further includes determining the value of the electrical parameter corresponding to a change in the time rate of change of the electrical parameter, wherein the change in the time rate of change of the electrical parameter exceeds a predetermined threshold, and controlling electrical power applied to the heater so as to maintain the temperature of the heater about a target temperature that is a predetermined level below the heater temperature at the time at which said change in the time rate of change of the electrical parameter exceeds the predetermined threshold.
Abstract:
A heated fuel injector for supplying fuel to a fuel consuming device includes a fuel inlet for receiving fuel, a fuel outlet for dispensing fuel from the fuel injector, and a fuel injector body extending along an axis and fluidly connecting the fuel inlet to the fuel outlet such that fuel flows within the injector body. A cylindrical heating element radially surrounds the fuel injector body and operates to heat fuel flowing through the fuel injector body. An annular space is defined between the heating element and the fuel injector body sufficiently large to accommodate thermally caused radial differential expansion between the fuel injector body and the heating element. A conductive material fills the annular space and has a melting point sufficiently low to be a liquid as the heating element operates to thereby substantially prevent transfer of mechanical stress to the heating element due to the radial differential expansion.