Boone, N.C. Providing automotive design engineers with a source of instant heat for cabin air, engine fluids and other automotive applications, TT electronics IRC Wirewound & Film Technologies Division has developed a tubular aluminum substrate resistive technology that delivers tightly controlled "instant on" heat with greater than 95% efficiency. The new Anotherm series inline heaters, based on the new technology, can also serve as a voltage drop source for daylight running lamps and fan speed controls.
The Anotherm inline heaters, which consist of rugged thick-film resistive elements deposited on tubular anodized aluminum substrate material, can be tailored for virtually any automotive heating application, said the company. The low thermal mass of the aluminum substrate provides "instant on" and "instant off" capabilities, and by using multiple "zones" of resistive circuitry, precise temperature control is possible.
The Anotherm substrates are made from 6061 or 6063 aluminum alloy, with an insulation system consisting of a thin layer of anodized aluminum oxide chemically grown on the outer diameter of the aluminum tube. This produces a dielectric layer approximately 0.0014-in. thick (0.035 mm), which provides an inorganic insulation that is not affected by temperature or chemical exposure, according to the company.
As a result of the rugged construction, the Anotherm technology can operate in extreme temperatures, up to 300°C continuous operation, with a temperature coefficient of resistance (TCR) of less than 50 ppm/°C. Currently, the Anotherm material can be made in diameters from 0.5 to 1.5 inches (outer diameter) x 9 inches in printed length.
Wilson Hayworth, product manager at IRC's Wire and Film Division explained that diesel and hybrid vehicles don't produce sufficient engine heat to supply cabin air at the proper temperature, particularly during the engine's warm-up. The new Anotherm tubular heaters can supply "instant on" heated cabin air, and can also be used to instantly boost defroster air temperature to eliminate window fogging in cold weather, he said. Other automotive applications include diesel fuel warmers, wiper fluid heaters, EGR air intake heaters, heated seats and steering wheels, fuel pump flow controls, air brake purge valve heaters, rear-view mirror de-icing, and fuel cell heaters.
Key design advantages of the new Anotherm inline heaters include the single-piece construction with integral hose fittings, unobstructed fluid flow and precise temperature control. Custom circuitry can be developed to deliver the specific power density needed for each type of automotive fluid, said the company.
The patent pending Anotherm inline heaters can be designed specifically for each customer's application. Typical pricing for the Anotherm substrate material starts at $0.15/square inch. Delivery is approximately six to 12 weeks for prototypes.
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