Is this another hoax or could there be something to this concept?
I wouldn’t say it’s a hoax as in a deliberate attempt to defraud investers. Inventers often fall so in love with their ideas that they lose sight of reality, they start believing their own hype, they exagerate the imagined disadvantages of existing technology.
As far as I can tell, this engine exists only on paper so far and everything works just fine in a computer animation.
When, or if they ever build a working prototype, I suspect they may very well find that it is a disappointment.
I peronally believe that the claimed efficiency gains are pipe dreams of a sincere inventer.
B.L.E., I’ve been away from the keyboard since I last posted, but I did want to get back and tell you that after signing off Saturday I realized you were correct. The inertial energy in the piston is converted into other forms of energy, mechanical (inertial) and a bit of heat energy (friction in the cylinders, bearings, and a teeny tiny bit as the connecting rod is pulled on and the crank is pushed on.
Sorry to take so long to get back.
I think your point about the Wenkle is valid, but i think biggest problem with the Wenkle engine was the difficulty sealing the combustion chambers.
This kind of energy conversion method is very popular in aviation. That round thing that hang below the wing of an airplane has a separate compression section, combustion section, and a power section. It just haven’t been applied to a reciprocal application.
Actually, the concept of compressing the inlet air has been applied to reciprocating engines. The only thing I can see that the secondary piston in this split cycle engine is doing is increasing cylinder pressures and thus volume. And that’s exactly what superchergers and turbochargers do. As I mentioned earlier, I can’t see why a supercharger or turbocharger wouldn’t be a more efficient way to accomplish this than a piston pump. And they’d be a much smoother way too.
B.L.E. may have “hit the nail on the head” on this one. Except that I understand that they’ve built a prototype. While I read that the prototype works, I seriously doubt if it’s efficient. I suspect that the concept goes back to the days before turbochargers and perhaps before surerchargers.
Even with super/turbo chargers, the increase in pressure is low relative to the compression that occur inside the cylinder. An strong turbo add about 14 psi, which is about 2x atmospheric pressure. In a gasoline engine with a compression ratio of 11:1, air pressure increases to 28x atmospheric (the number is that high). An intake system that can support this kind of pressure would be quite heavy. No more lightweight, easy to produce molded plastic manifolds.
The idea here is separate and it allows for some flexibility in engineering. A conventional piston that sees both compression and combustion has to be optimized for both. In the split cycle engine, parts can be optimized for their specific separate tasks. Compression piston that never sees high heat and pressure of combustion can be build with cheaper and lighter material. Cooling system that only needs to worry about the power pistons so it can be smaller and lighter. You can build an Atkinson cycle by using a smaller compression cylinder, thus improving engine efficiency.
However I see your point on a rotating compression device; if there is a gas turbine that is efficient at low and high power settings, that would be ideal.
I’m just not sold that sharing the compression function with a seperate cylinder is more efficient than having it performed by the piston in the combuustion chamber, or that boosting pressures to the levels usable with pump gas would be more efficiently done with a pistom pump than a turbocharger. In either setup, one cylinder realizes the high heat and stresses of combustion, and it seems more efficient to use the same pistom for both compression and combustion.
Granted it’s possible to create higher pressures in the combustion cylinder with e seperate compression piston, but that brings the engine out of the category a a pump-gas engine. And it takes energy to compress the fuel/air mix whether you do it using the combustion piston or a seperate piston.
Turbochargers and superchargers can already bring cylinder compression to the verge of preignition and beyond even using premium gas. Waste-gates are already needed to prevent overpressuring. Where, I wonder, would be the benefit of the engine that’s the subject of the post?
I suspect this is a very old idea that’s been superceded by modern technologies.
My read leads me to believe the fact that the ignition happens after TDC, rather than before is the significant. http://www.scuderigroup.com/prototype/
Along with hydraulic valves that are exterior to the cylinder
"On the compression side of the Scuderi Engine, the breathing problem is solved by reducing the clearance between the piston and the cylinder head to less than 1 mm. This design requires the use of outwardly opening valves that enable the piston to move very close to the cylinder head without the interference of the valves. This effectively pushes almost 100 percent of the compressed air from the compression cylinder into the crossover passage, eliminating the breathing problems associated with previous split-cycle engines."
“I’m just not sold that sharing the compression function with a seperate cylinder is more efficient than having it performed by the piston in the combuustion chamber”
Agreed. Simply separating the functions of the cylinders won’t increase efficiency significantly. There are bits of saving that can be found. They may not be obvious, but that’s why people do research.
"Turbochargers and superchargers can already bring cylinder compression to the verge of preignition and beyond even using premium gas. Waste-gates are already needed to prevent overpressuring. Where, I wonder, would be the benefit of the engine that’s the subject of the post? "
Turbos by themselves, in their current forms, cannot bring intake air to the fuel’s ignition temperature. It has to be combined with a compression stroke once inside the engine to achieve ignition temperature. However, the potential is there. The pressure ratio acheived by the compressors of jet engines in airliners is reportedly at 40:1. That’s equivalent to a compression ratio of 13:1. However, the compressor constitute a significant portion of the engine, not an accessory sitting on the side of a reciprocating piston engine.
It’s true that superchargers and turbochargers could not bring combustion pressures to the level of self-igniting without the power piston’s compression stroke, but they’re not intended to. They increase pressure. The point is that they already have sufficient ability to increase it beyond the preignition point when combined with the compression stroke.
Piston pumps cost energy to run. Turbos make use of some of the energy currently wasted (although I recognize the small backpressure issue). I just don’t see the benefit of the former over the latter.
Aircraft engines are an entirely different animal. I know the point is one of comparing the first stage compressors to the compression in an automobile engine, but aircraft engines are a continuous burn process and the compressors are rotating systems coaxial to the main shaft rather than reciprocating and seperate. And aircraft engines are terribly inefficient until they’re wound up, whereas auto engines have to be efficient over a wide rpm range. It’s apples and oranges.
I’m not buying it as an advance, but I also realize that when something is actually built and tested results can be different from what would have seemed apparent. Tests of two same-design engines, one with the added precompression stage and a second with another boost system (supercherger or turbocharger) would convince me if, in fact, the data showed this to be superior.