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February 27, 2007

Fuel injection

DefenseTech notes a seemingly innocuous tender for the United States Air Force meant to have a most ocuous effect, viz taking on integrated air defense systems. It turns out to be something auto manufacturers have been using for some time; a technology the USAF is calling "active combustion control."

Aircraft engines using active combustion controls should be able to fly longer distances at a lower rate of fuel consumption.

With today's engine technology, the flow of gas into the combustion chamber is fairly unrestricted, which is not very efficient. Many years ago, the automotive industry fixed this problem with fuel injectors, and now the aerospace industry wants to make a similar leap -- although at a far greater level of sophistication, of course.

Next up: Temperature controlled cup holders and a dvd player for the back seat.

Posted by Ghost of a flea at February 27, 2007 06:41 AM


Not quite. The jet engine builders have been installing FADEC for at least two decades (Full Authority Digial Engine Controller), from which the auto manufacturers have derived their current computer engine controllers. Essentially, FADEC monitors external engine conditions and moderates the fuel flow to achieve the desired power setting. This USAF proposal is asking for a sensor suite inside the combustion section, to monitor the real-time air flow inside the can, analyse the composition of the flame inside each can, and allow the FADEC to adjust the fuel flow (1000 x second) for optimum power and reduces undesirable emissions. In a car scenerio, the engine computer would have sensors inside the combusion chamber; with their data, it would modulate the fuel injection cycle and the ignition spark (timing and duration) to directly control the power and emissions from each individual cylinder in each power stroke.


Posted by: J.M. Heinrichs [TypeKey Profile Page] at February 27, 2007 10:29 PM

Hmm. Someone hasn't heard of FADEC, nor read the USAF proposal.


Posted by: J.M. Heinrichs [TypeKey Profile Page] at February 27, 2007 10:32 PM

I plead ignorance (and defer to your authority). Best let the guys at DefenseTech know... those chaps are well connected.

Posted by: Ghost of a flea [TypeKey Profile Page] at February 27, 2007 10:39 PM