Tuesday, February 9, 2010
FADEC Comes Of Age
Simplifying engine management with Teledyne Continental
Face it. Computers are taking over the world. Like it or not, more and more of those functions we used to perform manually are being accomplished faster and more efficiently with electronic assistance. Perhaps surprisingly, aircraft manufacturers weren’t the first to embrace computer technology. The Pratt & Whitney F100 engine in the McDonnell Douglas F15 Eagle fighter was one of the first to feature a digital electronic control system to help the pilot manage power. Private piston and jet aircraft engines are only now being re-engineered to accept computer control, and the new system is known as FADEC (Full Authority Digital Engine Control).
As the name implies, FADEC entrusts full authority of all engine operating parameters to a computer. The system effectively replaces both magnetos, eliminating mag maintenance and timing. By definition, it can be installed only on a fuel-injected engine, thereby eliminating carburetors and carburetor heat. Additionally, mixture and prop controls disappear, and engine priming is controlled based on temperature and pressure. Because FADEC maintains the fuel/air ratio on each individual cylinder within narrow tolerances, it bypasses the most common cause of engine failure: mismanagement of the mixture control.
Teledyne Continental Motors (TCM) has been a major pioneer of FADEC technology, and the TCM system brings a level of simplicity to the cockpit that many pilots have never experienced. The mixture and prop controls go away, and the engine is managed by an electronic control unit (ECU). The pilot commands power with a single lever, similar to most turbine engines. TCM’s FADEC system is one of the first to be brought to a modern production aircraft.
TCM has designed and adapted a FADEC for engines from the bottom to the top of the company’s piston product line, the IO-240, IO-360 and IO-550 powerplants. (The recently introduced Cessna Skycatcher’s O-200D is excluded because it’s carbureted.) The computerized system controls every engine parameter to optimize performance and efficiency.
The TCM FADEC system on Liberty XL2’s IOF-240 monitors air density, the CHT and EGT of each cylinder, and the temperature and pressure of intake air; it also controls engine timing, analyzing data from the engine with a refresh rate as high as 70 times a second. FADEC then distributes a precise amount of fuel to each cylinder independently. If one cylinder begins running hot, then FADEC directs more fuel to that cylinder rather than flooding the entire engine with additional cooling fuel.
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Labels: Aircraft Maintenance, Learning Center, Modifications, Aircraft Upgrades, Aircraft Engines, Engines