http://www.coatesengine.com/

Ultimate thermodynamic efficiency of *any* heat engine is dependent upon the difference between maximum and minimum operating temperatures:

http://en.wikipedia.org/wiki/Thermodynamic_efficiency#Carnot_efficiency

So Scuderi’s claim that increasing the *speed* of air-fuel mixture burn produces a 5% increase in thermal efficiency doesn’t ring true:

http://www.scuderigroup.com/technology/theory_of_operation/summary_of_gains.html

As for the other claimed efficiency improvements…

—Use of ceramics: They don’t explain why ceramics would benefit a Scuderi design more than a conventional ICE.

—Lean-burn: lean A/F ratios increase combustion temperatures (hence NOx emissions) regardless of when the mixture is ignited, so the claim that the engine wouldn’t need a NOx catalyst is dubious.

—Advanced piston motion: It is unclear why these piston/rod design criteria couldn’t be applied to a conventional ICE.

Finally, I don’t see anything that this engine does that couldn’t be accomplished by judicious application of variable valve timing, direct fuel injection, piston/head/combustion chamber optimization, and conventional supercharging/turbocharging.

My suspicion is that the computer modeling assumes “perfectly smooth” engine operation, so that effects of hot spots, misfires, non-homogeneous air/fuel charge, etc. are ignored, but would be problematic in the real world.

No way production worthy engines will be ready in that time frame. Based on what I could find on the Scuderi website, no physical prototype has been built yet. All of the efficiency improvement claims are based on computer models. Computer modeling works best when the underlying technology is well understood and the appropriate equations can be devised, constants understood, etc. In my years as a engineer I have yet to see the final result of a prototype effort outperform the computer models, yet often the opposite has been true. Losses and issues which were not foreseen often come up once you get to the physical stage.

Computer models said the Boeing 787 would be in the air by now, but it isn’t.

There have been many, many alternative ICE designs over these past 100+ years, and only a few of the promising ideas actually work out.

I think one problem with this would be vibration. With a traditional 4 stroke or 2 stroke, the cylinders (either inline or V) generally cancel out the primary vibrations of the other but with an engine with unequal pistons would have unequal forces from the accelerations of the pistons and thus greater vibrations.

http://en.wikipedia.org/wiki/Crower_six_stroke

The thought of seeing a Chevy Tahoe hissing steam from its wheel wells like some old locomotive seems somehow apt.

Thanks

Thanks. I’m thinking that a typical piston compresses air much more than any turbo or supercharger, which is why I was wildly fantasizing about a turbine compressor.

The crazy picture that came to mind was the opposite of the 1930s Italian attempt to create a jet engine by using a piston engine to drive a compressor whose compressed air was fed into typical jet combustor. Can’t remember the name at the moment, but it did actually work in that they built a flying prototype, but weight, perfomance and fuel consumption were all too poor for the idea to really take off.

In any case, it’s fun to speculate!

I’m pretty sure that this requires FAST direct injection in order to work efficiently, in order to prevent fuel from leaving through the exhaust. Also, it would be a nightmare to do closed loop emissions control on.

Speaking of fast direct injection, a plain old Wankel would be a better recepient here.

Finally, if you’re going to compress the air, why not just use some sort of totally external compressor?

I don’t know too much about this, but from what I understand computer models have still shown a net gain in efficiency even with the 2nd set of pistons. The reason not to use an external compressor is because piston technology is very mature and the Scuderi engine could be manufactured on existing equipment.

An external compressor is exactly what’s used by a Miller cycle engine, with a supercharger.

Great questions and I wish I knew more about it.

I’ll assume the answer to the added size and weight and friction is that the engine is so much more powerful/efficient that those losses are covered and there are still gains.

Now, combine this split-cycle with elctro-magnetic valves and… ICE hey day!

http://www.scuderigroup.com/technology/animations/split_sideview.html

Finally, if you’re going to compress the air, why not just use some sort of totally external compressor? I could imagine having a turbine compressor to supply a constant volume of pressurized air to an accumulator tank. I’m sure there are a lot of reasons why this would be impractical (cost would be one of them), but it would be great to have a source of bleed air to run accessories.