I haven't gotten into all the details of the Ecoboost but a key part of it is the use of a turbocharget. If I recall correctly (I should really look these things up) an Atkinson cycle engine with a turbo or supercharger is a Miller cycle engine and has much the same characteristics. I'm not really sure if the added exhaust backpressure is a problem.

For MyPart, the FEH 2.3 is a lot different than the standard FEH. Because of the compression ratio differences, I'm sure it has different pistons, heads and rods and perhaps a unique crankshaft.

 

Am I missing something but FORD list the Bore and Stroke as the same on the non-hybrid and hybrid models (3.44 x 3.70) and of course they are both 2.3L (2261CC).

While the heads and pistons may have changed the block, rods and crank should have stayed the same, right?

 

I understand your concern over ease of syphoning but I am not sure that is really possible. In pictures I thought I have noticed what appears to be a key lock mechanism to prevent unwanted access to the fuel tank.

Here are a couple of articles on the system although they do not mention the key but the first article references the technology used that is designed to prevent syphoning.

http://aftermarketbusiness.search-au...tegoryId=42037

http://www.prdomain.com/companies/F/...0068934773.htm

http://www.dispatch.com/live/content...A.html?sid=101

 

Well, let's hope you saw the lock, because all one would have to do is have a standard nozzle shaped hose end to get into the cap.

 

Probably true...but as with most things in life...if someone wants it bad enough they will find a way regardless of a lock or not.

 

I believe the capless gas tank does include some "theft protection"....and I don't think a nozzle shaped hose would defeat it. I mean, It could be as simple as something like an inline strainer just beyond the reach of the nozzle. Fuel can flow through it, but a longer hose can't get down into the tank to siphon off any fuel. I'm not saying that is the method they empoy but that is my cheap and easy guess as to how it could be done.

Also, I know on some foreign models (I think the Taiwan escape of 2004-2007) they have a "locking" fuel door with an in cabin door release. I even saw someone on escape-central.com ordered the parts and installed it on his domestic version.

 

COULD have stayed the same. When the piston and compression ratio change, the geometry of the crank and rod may have to change because the internal angles and clearances are affected. If someone has access to a Ford parts list it would be interesting which engine internals are interchangeable. (At least interesting to us gearheads.)

 

Capless Fuel...Here is a link to the picture I referenced with the key.

http://www.topspeed.com/cars/ford/20.../pictures.html

and the closeup:

http://www.topspeed.com/cars/ford/20...e227761-4.html

Also the following exerpt is taken from the Aftermarket Business link I referenced a few posts above:
Easy Fuel also has a patented mis-fueling inhibitor to reduce improper fueling and siphoning. The inhibitor consists of a fuel nozzle detector that guides the nozzle to the opening. If a nozzle or foreign tube of a different size – a diesel nozzle or plastic hose, for example – is placed in the filler neck of a gasoline-powered vehicle, the latches will not release. For a diesel-powered vehicle, the inhibitor will keep out the smaller gasoline nozzles.

To protect the fuel filler neck from dirt, dust and debris, Easy Fuel relies on a flexible rubber seal in the body housing. The system also comes with a handy plastic funnel, which is stored with a vehicle’s tire changing kit, in case someone runs out of fuel and needs to add a gallon or two from a portable container.

“Because fuel cans are not standardized in terms of their nozzle, we needed to make sure customers could easily get fuel into the system if they ran out,” said Aitken. The funnel is the same diameter as an unleaded fuel pump nozzle for a gasoline-powered vehicle.

 

In the past, the compression ratio on the hybrids is different due to different valve timing. Essentially the valve pops open during the compression stroke. Its what makes it an "atkinson cycle" engine of course.... so they wouldn't HAVE to change the linkages/piston, etc to get a different compression ratio. Just the cam shaft I'd imagine.

 

No, No, No! We've argued about this before. You cannot change compression ratio with valve timing. The compression ratio is a mechanical measure of the combustion chamber minimum and maximum sizes and has nothing to do with when and for how long the valves open. The Atkinson cycle has a very high compression ratio and then compensates by leaving the intake valve open longer. This reduces the maximum pressure in the cylinder and prevents detonation but does not change the compression ratio.

There is no way two engines with different compression ratios can have the same internal parts.