Would be good for plug-in range extender. For conventional application would take long time to get into mainstream.

When one talks about a 10% increase in efficiency it is a multiple of the root number. For example: a 30% efficient engine increased by 10% is a 3% gain not a 10% gain. In any case a 25%-50% gain in efficiency would increase an engine from 30% to 37.5% or 45% efficiency...darn good!

Toppa Tom,
I don't think Southwest Research a worldwide organization with an excellent reputation, would release anything, especially a video of the engine running, if it was not firing "after top dead center" as they claim it to be. Why is it that you are always so negative on this great invention??
Where is Roger Pharm??? At least he has constructive opinions on the Scuderi Split Cycle Engine.

The only things that concern me regarding this engine are:
-durability of the crossover valve
-engine balance
-frictional losses when the compressed air crosses over

Regarding "frictional losses when the compressed air crosses over" some back of the envelope calculation would help understand.

Assuming no energy get added (no combustion), relative to losses during air intake:

1. Assume compression ratio is 10:1 (rho_c = 10 x rho_i)

2. Assume Intake and crossover flow cross section area are equal.

...

3. Mdot_i = rho_i x V_i x A

4. Mdot_c = rho_i x 10 x V_c x A

5. Assume crossover time is 5x faster than intake. ... Mdot_c = 5 x Mdot_i

=> rho_i x 10 x V_c x A = 5 x rho_i x V_i x A => V_c/V_i = 1/2

6. Drag loss is related to rho x V^2 (assuming all else equal)

Loss_c / Loss_i = (rho_i x 10 x (1/2)^2) / (rho_i x 1^2) = 10/4 = 2.5

So Loss_c / Loss_i ~= 2.5

But it is inversely related to the square of crossover time, so if that is 3X faster than intake instead of 5X faster, the losses are nearly equal.

Anyhow, I believe intake losses are pretty minimal as long as no throttle is present.

I have worked with the Southwest Research Institute and indeed they do have and deserve an excellent reputation.

They would never refuse to release a video of a client's engine running, if the client so desired.

I have no reason to doubt that the engine was firing "after top dead center" as they claim.

But we're all still waiting for ANY real data from this Rube Goldberg engine.

TT and Roger
I'm sure Southwest Research is collecting data for the various OEM's who signed NDA's, however for some reason they won't release the details to the public. Is there anybody who can shed some light on why this information is only being made available to the OEM"s that signed NDA's? My opinion is if the results were outstanding news why wouldn't they want the entire world to know the results? Wouldn't this help their cause both commercially and politically?? What do I know anyway,
Have a nice day!!!

JT-It's definetly running on petro;
From the compression chamber, highly volitale air is moving towards the combustion chamber via the "cross over passage", this is a new invention, wih patents received, yata, yata. Bosch Engineering fabricated the fuel injection and timing systems along with several other important components for the engine. The fuel is then being injected at the top of the combustion chamber with perfect timing, on the down stroke with highly volitale air and the combustion process is now completed. This is what we call firing "after top dead center" a cleaner burning fuel with better efficiency and torque. I think it's pretty impressive that JT and others thought it was running on just air.

"Is there anybody who can shed some light on why this information is only being made available to the OEM"s that signed NDA's?"

If you are implying that Scuderi does not utilize a NDA and allows SwRI to release any/all information you could not be more wrong.

Scuderi itself releases all this non-information that may or may not relate to anything real.

There are also other solutions than Scuderi engine to achieve same performances but using the the Carnot cycle. To see more consult: http://www.hibridesign.com/prod02.htm .
This technology opens the perspective to achieve small-size engines with half the number of cylinders reported to the same power as a classic four-stroke engine. The high power density recommends this engine for automotive, aircraft and navy applications as well as for stationary construction. When it is used in the automotive powertrains, the engine can have a hybrid operation option that attains the partial recovery of the braking energy (in city) and the exhaust gases energy (in highway). Compared with an electric hybrid system, the proposed solution eliminates the electric generator, motor and battery components which are additional to the engine. This reduces cost, complexity, weight and bulk while providing similar function and benefits. In case of the hydrogen utilization, the engine configuration largely compensates the low energy density per unit volume specific of this fuel without any supplementary adaptation. A spark ignition variant supplied with hydrogen can reach an efficiency superior to 40%. This invention was obtained a medal at International Invention Exhibition Geneva 2009.

@ToppaTom,
You've said it: "...piston side loads are lower on compression and expansion and higher on intake and exhaust." Please be reminded that at 2000 rpm typical cruising at high load, the inertial loads on the pistons are quite low in comparison to the force of the power stroke and of the compression stroke, hence substantial reduction in side loading on the piston. At higher rpm's such as at 5000 rpm at low load, then, piston inertial force from reciprocal motion become much stronger to become the dominant force on the piston side loads, and in this case, Scuderi arrangement is of no advantage to conventional design.

Conventional splash lubrication should be sufficient, albeit a lot more oil cooling may be required in the absent of the cooling intake stroke in the power cylinder, and they may have to set the coolant at lower temperatures to bring get cooling down to par with conventional Otto engines. Furthermore, firing after TDC should significantly lower the combustion temperatures. We shall see how the heat problem will be solved. As the last resort, water injection may be employed for a brief moments when high power output is required, since an auto engine runs most of the time at much lower power than its rated output. The load-leveling feature of the Scuderi engine will greatly reduce the frequent needs for higher power output, so, water injection, if necessary at all, will rarely be needed.

The considerable efforts of the Scuderi family in developing this concept is very methodical and are very commendable. They've covered all the bases as far as R&D is concerned.

1. The side loads during exhaust, when the rod must push the piston up look very severe. More so because the cylinder will be hot and dry and the rod angle (on a radial arrangement) is so large.

2. The pictures and the movie seem to show an in-line engine, where crankshaft offset would provide no more benefit than in a normal engine (which is like, none).

3. An engine that is limited to anywhere near 2000 rpm will suffer a severe weight penalty. The bad con rod angles, the crossover flow and the ATDC firing do seem to imply a much lower rpm limit than a normal engine.

4. Firing after TDC should significantly lower the overall effective compression ratio (and BMEP).

5. The 10 year efforts of the Scuderi family in developing this concept could have been duplicated by a team of PR hacks and one person with a drill press.

This is a 10 year effort by Scuderi - NOT SwRI.

And it is Scuderi that says the actual prototype data confirms their claims.