Delaney Power Extractor Engine


Hi All,

I came across this website through a friend of mine

and this new engine sounds pretty impressive, but I don’t know enough

myself. What do you all think, is it really good as my friend said?

Thanks in advance for help



I’m not an engine engineer, just a run of the mill mechanical engineer. In concept, it sounds interesting. However, it has a tremendous amount of mechanical hurdles to overcome. Many of which will zap power like the exhaust “supercharger.” I love 2-stroke engines for their weight and power. But they suffer from issues with emissions. Modern electronics will help prevent expelling unburned fuel, but the actual design will suffer from a lot of inefficiencies. I suspect if they can even get a functioning prototype, they will struggle with meeting current emissions regulations or meeting the fuel economy gains they propose. It’s an interesting concept though.

I’m not sure I’d want the task of designing an elipticle crank that can survive the stress an engine would provide.


Interesting discussion, however there are a few weaknesses in the theory.

The first is that it would likely take more energy to run the pump(s) than it takes to push exhaust gasses pass the valve and out the exhaust in an engine without the powerxtractor. In short, there’d be no gain.

The second is that I noticed the author converted the engine to a 2-cycle. 2-cycle engines already have higher power to weight output becuase they fire at every stroke…that’s why they’re the engine of choice for power tools…however they also have far higher emissions outputs. They’re expected to be banned even for small offroad vehicles and power tools due to the emissions.

The best way to reduce losses due to turbulance and other restrictions in the exhaust and input paths is to directly reduce the restrictions themselves by opening up the ports (porting), opening the valves more and/or longer (high-rise and/or high duration cams), and adding headers and low restriction exhausts and intake manifolds. Superchargers and turbochargers go even farther by forcing the fuel into the cylinders under pressure. With the exception of the super and turbochargers, these changes do not take any power from the engine, however since they do allow more fuel to move more readily through the cylinder they do have a tendency to reduce gas mileage…unless you have an EXTREMELY disciplined right foot…and they do increase the challange of emissions control.

In short, I’m not “sold”. However, I maintain an open mind, and would be interested if there were some objective and testing-based evidence.


For those who just want the meat and potatoes, go here:
It looks like a plausible idea. Now, let’s see if it’s feasible. BUILD IT, AND THEY WILL COME.


I’m not impressed with it either because of the pollution problems.

I ran across a reference to a 5/6 stroke engine recently. The extra cycle has water injected into the cylinder head, which turns to steam, providing extra power while cooling the engine. Interesting in that half of the power loss in a IC engine is heat (other half is exhaust), and this extra stroke uses some of that waste heat.


Interesting at first glance. Simply retiming the valves on a 4 stroke will not allow for proper intake or exhaust of combustion gases. 2 strokes use the negative/positive pressure fluxuation in the crankcase along with ported pistons to get exhaust gas out without scavenging fresh air/fuel mix. This would be almost impossible to achieve with 4 stroke heads.


Inventors often suffer from a blind spot that makes it impossible for them to see just how terrible existing technology is not, or they prescribe imaginary disadvantages to existing technology while ignoring the very real drawbacks of their new idea.

Even the most preposterous engine designs work in computer animations. Let’s see an actual running engine and see how well it works. I suspect that at best, it may be a “great step sideways” like the Wankel engine.


I agree. The illustration shows a reciprocating piton engine in a cylindrical configuration. It hardly seems practical for an automobile. And the lob on that camshaft is so big relative to the cylinder size. How would all that mass affect the way the engine runs?