DARPA actually designed something useful?!

[Leonidae]

*click* read and watch the video...

oh, and at ze mad german scientists accent.

 

[Tornado]

Um, internet?

 

[Jay]

Interesting video but IIRC opposed piston opposed cylinder engines have been designed before. Or atleast opposed piston (2 pistons 1 chamber) engines.

 

[Philly]

It doesn't really sound like much new. Opposed cylinder engines have been done before. Boxers have been done before. The only real innovation is putting the second piston on the same crankshaft, and then putting it in a flat format.

I would enjoy seeing them try to package it to actually be used. The engine is very wide/long (depending on how it's mounted) and it would really only be useful when transversely mounted and running three banks, so twelve cylinders. A hatchback with a 5 foot long engine just wouldn't be practical.

 

[Leonidae]

well, that is the prototype for a TRUCK.. for smaller vehicles it would naturally be downsized. although, I don't believe that it will beat conventional engines.

 

[Philly]

I could see that being used in a truck. Or maybe trains that already use opposed piston engines. But a regular opposed piston engine already takes up a good amount of space so you'd need a pretty big rig to put the engine into.

But in a car you still basically have two boxers sitting side by side so even if you downsize it it's going to be too wide or long to practically fit in anything. If space wasn't an issue in a car engine bay I'm sure we'd still see things like Inline-8s anyway.

Not to mention that it's going to be a very long, wide but flat box when put all together, so it isn't exactly the most efficient use of space.

 

[Jim Prower]

I could see that being used in a truck. Or maybe trains that already use opposed piston engines. But a regular opposed piston engine already takes up a good amount of space so you'd need a pretty big rig to put the engine into.

But in a car you still basically have two boxers sitting side by side so even if you downsize it it's going to be too wide or long to practically fit in anything. If space wasn't an issue in a car engine bay I'm sure we'd still see things like Inline-8s anyway.

Not to mention that it's going to be a very long, wide but flat box when put all together, so it isn't exactly the most efficient use of space.

To my knowledge, there have been only two manufacturers who have used Opposed-piston designs in land-based vehicles (trains): English Electric with their Napier Deltic-engined Class 55 locomotive and Fairbanks-Morse's entire locomotive lineup, from the meager H-10-44 switcher, All the way up to the H-24-66 Train Master, at one time the most powerful single-engined diesel locomotive in the world. All Class 55s have been taken out of regular service, and only a few F-M locos, switchers, are still in operation. Most often the engines used now (around the world, at that) are GM's 645 and 710, and GE's FDL series. Both conventional Vee engines.

The main problem outside of ship use for OP engines is reliability: the Deltics were the only moderately successful engines to have an OP design, and their triangular shape didn't help space much. This design I could see having problems with the long conrods, as they're now effectively columns in design, as well as the awkward piston joint. It would also require more cylinders to match the displacement of other types of 2-stroke diesel, and there's also the problems of Loading gauge in things like locomotives: the engine may not fit inside a tunnel, even stood on edge!

It may be interesting to move or remove one side of the engine, thus making it a tall-cylinder straight or Vee engine. A straight engine would not be much taller than the Fairbanks-Morse engines of old.

 

[EA11R]

Not to mention that it's going to be a very long, wide but flat box when put all together, so it isn't exactly the most efficient use of space.

Sounds like low centre of gravity to me!

 

[Philly]

Then what's wrong with a regular Boxer?