Direct Fuel Injection for Pison Engines.

[nomorecatering]

Just watched a video on the development of direct fuel engection in the automotive world. Some of the advantages of this include.


Fuel directed straight into the cylinder similar to diesel engines, at 26,000 psi give extreamly fine atomisation. Addtionally, the injection sequence can be fine tuned as required. Indeed the injecto could give up to 5 short pulses instead of one squirt.

The atomisation sequence gives a large cooling effect on the air in the cylinder, allowing the engineers to raise the compression ratio from 10.0:1 to 10.5:1

The Porsche engineers say the new direct injection engines are more powerful yet more fuel efficient due to direct injection. The change over on the 911 gives a 40 hp power boost.

So my question is, if this technology could be parlayed into aircraft piston engines, could we see a similar gain. Note that Lycommings new Ie 2 engines feature a sequenial fuel injection system off a common rail, rather than the continuous flow settup from a fuel flow divider as is traditional.

Thoughts anyone.

[Brian Abraham]

Direct fuel injection was being used in aircraft engines prior to WWII. The German DB 601 used in the Bf-109 first ran in 1935. The direct injection loses the charge cooling benefits however, as you need to have the cooling take place prior to the charge entering the cylinder. In practice on Wright R-3350 it was found that efficiency was reduced . Although the cylinder was getting a precisely measured dose of fuel it was still subject to the vagaries of the induction system plumbing as to how much air the cylinder was receiving.