Technology | Mainspring Energy

Can anyone explain the low temperature, non-combustion reaction that powers this mainspring linear generator that just got a 150 million dollar order? It runs on “hydrogen or biofuels”.


I think its related to the Turbo Encabulator…

On a serious note its another free piston engine.
A technology that’s always just a few years away, make perfect sense and does show great promise. Its just really hard to make one that works.

On a serious note I found a real good animation of an OP free piston engine thats uniflow and a two stroke like mainspring. But I still can’t tell you how it does what they claim.

Here’s an Napier Deltic, an engine derived from the Jumo 205 and the Faibanks Morris OP engines ( still in production ). But those don’t have that beautiful deltic sound.
Trouble with a 2 stroke diesel ( or should I say a uni flow type like these to be specific )is they have a lot of trouble oil control and blow a lot of lubricant past the intake and exhaust ports. That’s probably why Mainspring is trying to build one without oil lubrication. I just can’t see how they do it


Plenty of shaking generators on Youtube, DIY
This mainspring energy is not a Non-combustion system

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Here is the patent:

If I read it right, basically it is a variable compression engine and they are using a lower compression, which delivers less power per stroke, but doesn’t generate all the heat and massive explosion you get from high compression. So it is slow burning but the piston can travel further to extract more energy for each stroke, and it gives more time for a complete burn which improves efficiency, and the lack of compression and heat reduces the NOx emissions.

I think this might be the money snippet. The ratios they are talking about are the geometric ratios not actual say compression. so the ratio of distance between tdc and the cylinder head and then how far it can travel.

"In some embodiments, the above-described engine includes a variable compression ratio less than or equal to the variable expansion ratio, and a length of the combustion section at top-dead-center is between 0.2″ and 4″. In certain embodiments, the variable expansion ratio is greater than 75:1. In other embodiments, the variable expansion ratio is greater than 100:1. "

If i understood is correctly, which is entirely possible I didn’t. It might actually be good for wood gas because it is a mixed gas. It has time for everything to catch fire.

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I don;t understand how you can patent that. Other people have designed engines with variable compression and expansion ratios. I think there is even one in a production hybrid car already (maybe a Honda ).

The description of the patent sounds like something that throws everything at the wall to see what sticks after the lawyers are done fighting over it…

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This engine presentation is pure Flim-Flam.
It is in the language of the presentation.
Read ANY real manufacturers engine presentations and nobody presents like this except the investment money trollers.

So of course the actual engineering will not make sense.
Sensible and questioning people is not who they are marketing too.
Pure eye candy.
Steve Unruh


Ford has a variable compression engine one of the F150 engines. BUT when they are talking about variable compression, they are actually referring to a travel length of the piston, and the only way do to that is to dynamically change the crankshaft and then you have a physical limit before the rods hit the side of the piston.

Basically they increased the max theoretical limit of the piston travel over the atkinson cycle engine by over 3x and eliminated the crankshaft. It is about energy conversion, not about rotational power, there is no need for rotational shaft power.

I know I have thought about something very similar before I think it was when we were discussing opposable engines on the yahoo group. I agree the patent might be sketchy. I’m not 100% sure shannon miller wasn’t a part of that group. The name is familiar but that could be a coincidence, there are a lot of millers.

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Fuel testing single cylinder variable compression ratio engines (the"M" in the motor fuel specs) have existed for decades.
Big jump going from a limited use design to a mainstream design.
Honda is on their 5th design to make a true lower end Atkinson cycle engine. It still cannot meet their in-service wears for general use release.

And as the late 90’s into early 2000’s variable camshafts and CVT low mileage wear problems have shown well now; s-t-r-e-c-h-i-n-g out for the last remaining % of improvements can be overreaching.
You personally only what to open pocket book to systems been worldwide at least 10 years in general usages.

Let the deep-pocketed; and new-must-be-betters do the theta developing.
Talking; and throwing up concepts is cheap. Real developing is time/efforts expensive.
Steve unruh ( still working on 22 and 24 gauge SS welding)


It sure is curious that 99% of piston engines still use cams to actuate valves. And with those pistons directly driving a crankshaft… even if that shaft ultimately just spins a generator.

A piston engine with independently controllable valves, say via solenoid, with said piston pushing against a sprung linear generator would be infinitely tunable for power, efficiency and/or emissions.

But you can’t buy one and few exist outside University labs. My conclusion is that traditional engines are close enough to optimal that that last bits of efficiency are not worth the costs. A ~$1k Predator 670cc engine is an amazing amount of power for the cost. Who will pay double or more for a 15-20% improvement.


These are mainly for electric utilities right now. A 15-20% improvement for as much as they get used is completely worth it. Besides that they have to be solid state so they could easily be online and up to speed a lot faster then generators they do have now, so you don’t have to spin them up an hour ahead of time.There is a question on whether they actually are reliable. Just because a company claims x, doesn’t mean it is true. If they prove reliable, there is a huge market for them. But the only way to find out is to try it.

It isn’t about power as much as it is about efficiency. I don’t know what the power to weight ratio is. That determines whether it is even workable for mobile applications. It ends up to be a pretty long tube, so even if it does have a good power to weight ratio, it still might not work.

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