Normally a piston completes an up-down movement in 360 degrees. With this setup the top of the piston has an additional up-down movement in approx 60 degrees. So with the engine running at just above idle at 1000rpm this piston top will be moving back and forth as quickly as if it were 6000rpm on a conventional engine. It won't be able to rev up without *enormous* forces and consequent breakages to contend with.

@killer2600

11 ай бұрын

Typical redline limits are often due to valve float and we have conventional engines that have a redline of 12,000 rpm. So the lighter/reduced mass piston that isn't under load - no power stroke - theoretically should be fine.

@ostrichnews5011

11 ай бұрын

i agree that the redline would be lower- the crown would have to accelerate so fast even if it it pretty light it would still produce enormous forces. you may call these secondary primary forces, which means more balancing and forces.

@LM_Cams

11 ай бұрын

@@killer2600 the problem isn't the mass, is the mean velocity of the Piston. Above 25m/s of mean velocity the oil film just won't be able to form until the Piston rings pass again on the cylinder walls. In a conventional 4 stroke, that'd be 9400rpm with 80mm of stroke. That's insane already. But as already stated, if you put the crown Piston on a smaller windownof time, its speed will but a lot higher. Without considering the forces like you sad, even if it's very light. And yes, there are modified engines with higher mean piston speed, but the wear is guaranteed and won't have a long life span.

@alistairsmith4297

11 ай бұрын

This honestly looks pretty viable for low revving engines. I can recall one old model diesel that has an idle RPM of around 500, it could work a treat in an engine like that.

@chrisbetz3644

11 ай бұрын

​@@LM_Camssounds like a wet dream for Ford engineers

Feel like that cam pushing the piston back up will have some massive wear with such a big leverage and pushing the piston up so quick.

@24681359David

11 ай бұрын

The ball bearing should help with that.

@paulhollier6382

11 ай бұрын

It could still have useful applications, where high speed is not a requirement; like water pumps, or other engines that spend most of their time doing "slow-but-steady" jobs over a long period of time. You point is valid, though, and will have to be considered going forward, if this engine is to replace a normal piston engine in vehicles used for personal or general freight transportation (i.e. cars & 18 wheel highway trucks.)

@Eduardo_Espinoza

10 ай бұрын

@paulhollier6382 Yeah, maybe like a single piston range extender

@MrTimeMaster2

9 ай бұрын

​@@24681359Davidjust adds a failure point and a shit one to fix.

@gerrylorimer599

9 ай бұрын

Although the piston moves faster during part of the cycle, during this period the piston is not loaded significantly as it only exhausts the spent gases and pulls in the fresh air. It is only when the main cylinder rod is engaged that the piston is under the heavy load of compression and expansion! It may last longer than expected, but keeping revolution speed lower should extend life.

Those bits of metal banging together will be quite spectacular.

Cool idea but adding so much complexity to an engine is rarely worth it. Simplicity is king

@paulhollier6382

11 ай бұрын

This is true of all engineering, and is the end goal - "do more, and with less". From the writings of Golden Age of Science Fiction author, Robert A. Heinlein's classic novel, The Moon Is A Harsh Mistress: "How does one design an electric motor? Would you attach a bathtub to it, simply because one was available? Would a bouquet of flowers help? A heap of rocks? No, you would use just those elements necessary to its purpose and make it no larger than needed--and you would incorporate safety factors. Function controls design."

@revampedharpy09

10 ай бұрын

Yeah i was thinking this engine looks like a maintenance and repair nightmare.

@apollo7557

10 ай бұрын

Pretty much, plus don’t fix what isn’t broke.

@Eduardo_Espinoza

10 ай бұрын

@apollo7557 It's still nice that they're trying.

@NoahSpurrier

10 ай бұрын

Modern engines are more complex. Simplicity is nice, but you don’t get more with less when it comes to engine innovation. VW Beetle engines are nice and simple, but nobody is going to go back to using those engines.

Excellent video. My gut tells me this wouldn’t last in the long term. You’ve basically built piston slap into the system. With it firing like a 2 stroke it’s going to generate heat like a two stroke. I reckon it will make good power. But I don’t see it lasting 200,000 miles without expensive maintenance inbetween.

Making a 4 stroke combust twice as often is a good idea, theres a reason 2 strokes and Wankels have such good power to weight and power to displacement ratios. But with all of the added parts, the friction and intertia losses would sadly reduce those gains again.

@WeighedWilson

11 ай бұрын

This thing bangs twice as often but only gets 20% more power. That doesn't sound efficient to me.

@kaikart123

11 ай бұрын

​@@WeighedWilson tru, frictions is a bitch

@DailyLifeSolution

11 ай бұрын

@@WeighedWilson It does not bang twice. It has limits on revolutions. It achieves characteristic of two-stroke engine by different way to a certain extent.

@joshmanis9860

10 ай бұрын

just use the second power stroke to power accessories

@fabbri4497

9 ай бұрын

Wankel engines have a calamitous efficiency and specific power ! Just big displacement in low volume.

TBQH the entire video I was thinking that the crown piston wouldn't be very eager to move down on its own, which you addressed in disadvantage #11, including a desmo-like solution. Oh well, it seems that the standard 4-stroke Otto-cycle engine sits really in the Goldilocks zone for what regards complexity and performance/efficiency. With a Wankel or 2-stroke you get simplicity and performance, but not efficiency. With complex post-Otto designs you get better efficiency and power at the cost of complexity. Otto is just about good enough in all three departments.

@player1GR

11 ай бұрын

true

@davidaugustofc2574

11 ай бұрын

@@lurch789 because 2 strokes aren't as efficient as 4 strokes, so if you really care for mpg, why bother?

@Velktron

11 ай бұрын

@Lurch Even 2-strokes with separate oilers burn _some_ oil by design. Maybe less than agas-oil mix system, but still more than any 4-stroke. They even managed to release a few Euro 2 compliant scooters, but it's doubtful they could have gone much beyond that. But I wasn't discussing emissions in the first place, only efficiency. But since you brought it up... 2-strokes have higher specific power, but lower thermodynamic efficiency, and that in that sense they also have higher emissions due to higher consumption, even if you manage to avoid burning oil altogether.

I see a lot of added complexity and points of failure. It looks great on paper, and for very short term ownership I bet it works great. I bet I won't see too many of them with 300k miles on the odometer.

@ItzzzBeamo

10 ай бұрын

Another Wankel effect. Interesting.

@rubberduck4966

9 ай бұрын

fits well to the in-oil-running timing belt of the normal EcoBoost Engines..

@PD-yd3fr

3 ай бұрын

Truck engines need to last 1 million between rebuilds

@adcraziness1501

3 ай бұрын

@@PD-yd3fr I need my work van to last 1 million.

It's hard to call the ball on this one since it needs a lot of development and materials selection/testing. I believe that the mating surface between the two pistons is going to be very difficult to achieve. I'd like to hear one of these guys running and watch hp and torque numbers on a dyno.

@JBeamGT3

11 ай бұрын

It’s been achieved 😂, if you refer to the multiple references of the Ford Fiesta that has one of these engines. The real problem is the US government, they don’t want anything that puts the oil industry at risk. And innovative engines do exactly that.

@omnipotent87

11 ай бұрын

There are going to be major wear problems on the rings. The mean piston speed will be twice that of a conventional engine.

@hithereperson8137

11 ай бұрын

​@JBeamGT3 the government is forcing more and more regulated MPG across all makes and models, but that would cause the oil industry to take a hit, no?

@DieselRamcharger

11 ай бұрын

no, its not. this is stupid and anyone with even the most elementary mind should be able to see that. Dyno...lmao the piston speeds alone will destroy this thing at idle.

@VGHCX

11 ай бұрын

@@JBeamGT3 What's preventing China and other countries around the world from building these engines if they are as reliable as you imply?

Kudos for covering the disadvantages so well

A turbocharger provides the same kind of increase in power without all the additional wear surfaces. A modern two stroke uses direct injection which avoids the oil burning, and you can avoid it completely with a blower (detroit diesel) or even a turbocharger if you have a way to start it a blower or saved air pressure.

@marcob4630

11 ай бұрын

that's that!

@Diger65Line

11 ай бұрын

An incredibly complex solution to a fairly simple problem. as you state the modern two stroke designs with electronic fuel injection, closed sump lubrication and and controlled blown induction, produce an engine with fewer moving parts and simpler construction, however it's good to see that the Heath Robinson approach to engineering isn't dead yet. 😂😂

The fact that we use the design of the 4-stroke as it is for a century now without major modifications speaks for itself. Maybe its simply that good.

@wawaweewa9159

10 ай бұрын

For civioian use, but for military this gives more power which is more important than efficiency and parts replacement, or for other cases where the extra power and thus cost to maintain/repair is worth the work it will do for you while keeping things small in size, a CBA would have to be done comparing it to conventional engine that is larger but delivers same power

@neilkurzman4907

9 ай бұрын

Yes, but the attitude of we can’t improve anything ignores the fact that the four cycle engine has been improved greatly over the past hundred years.

@fabbri4497

9 ай бұрын

Or we follow the herd ...

Maybe it was just me but the pro vs con ratio was definitely slanted against, I hope decision-making isn't based solely on 20% increase in HP. Sounds like this needs more tweaking before being practical.

Finally something interesting for heavy duty low revving diesel engines. Interested to see a huge-ass naval engine with this tech.

The thing that strikes me about this design is the number of moving parts. Yes, it is far more efficient, but at what cost? I can see maintenance issues galore here.

The upper piston and crown piston constantly collide with each other so those are gonna need to be changed way more often. Also the upper piston might not compress the intake gases efficiently because it has no skirts so a slight tilt will increase friction and decrease compression A better solution in my opinion is to have compressed air (maybe supplied by a auxiliary pump) blow out the exhaust fumes right after the combustion

@michaelbuckers

29 күн бұрын

And at that point you don't need the piston to split and move up and down rapidly since compressed charge air does the job of forcing the exhaust out of the cylinder. So you can remove the entire mechanism, and then you get a turbo 2-stroke. Which means this whole system is just a needlessly complicated version of thereof.

I see another couple of problems: One is the lack of skirt in the crown will increase the wear on the bore. As it ovalizes, piston will go in sideways. Second is balancing issues. It already has a secondary shaft than can be used as a counterbalancing shaft, like 3 cylinders engines already have. I think a better solution than the spring would be replacing the entire cam concept by a linking mechanism. It is the most efficient and also prevents the piston from going rogue on the mechanism. However, that would have the most parts, not to mention a lot more points to lube. It would also need to be very precisely sinchronized or the linking mechanism would takes the entire force of the combustion stroke. Kinda similar to the Atkinson cycle tbh.

Excellent video. The discussion of pro- and con- adds so much to the visuals 😃 Really sets your hard work apart from other creators

Finally a good and critical video on an experimental engine

the ratling, noise and unrealibility of such desing is remarkable

Now thats what i call a one stroke engine

I see all the working parts of an ordinary engine and turn a bunch more parts that need to move. More moving parts means friction and inertial resistance. I can see the belt or chain drive and the lobed kicker that pushes the piston top wearing a lot and quickly. The idea is to remove as much parts and weight as possible resulting in more faster acceleration, more speed and smooth balanced operation.

Fascinating ! I love things like this. Thanks for showing us.🌞

Also the gas is exerting all it's force on the piston in a fraction of it's stroke length before it is expelled, so the transfer of force to the piston is probably less efficient

This is brilliant and I have faith in it , providing few modifications such as; offsetting the crank , hydraulic tensioner for the ( ring piston), xtra oil galleries and better bearing for rod

I'd love to know how high they revved those test engines up, and what problems they came across out of so many potential extra problems. The two piston halves clapping eachother, the sheer amount of force being put on that arm and its tiny roller bearing, piston slap from that pancake-flat crown piston, flex in that split con rod, extra balancing issues, etc etc.

Could this engine be a good candidate for "free valve" technology? Seems reasonable to me, as this would solve the cam issues completely.

@jamesclark4

10 ай бұрын

Free valve alone increases power by 30 ish %

It looks like the extra power output is coming from essentially tweaking the engine to put out more power (like street racers do). As noted by others, this drastically reduces the longevity of the engine wear items. Once the design has been balanced for longevity and desired power output, then we can determine the advantage of the split piston. The turbocharger is a good way to harness the energy dumped by the exhaust stroke to return it to the intake stroke. It is not clear to me whether this is a better solution for energy conservation than the current EcoBoost system that Ford has for the Fiesta and other engines. Ultimately, it's a balance between power output, durability and mass. All of that said, I would love to test this in real world conditions, with or without a turbo!😃😃

I really like your 3D animation style, the thumbnails always catch my eye scrolling through KZread. Do you model everything yourself? What kind of software do you use to animate and render everything?

This looks pretty promising. Nothing too fragile.

Még egy hiba lehetőség 🤌 gratulálok, biztosan nem fog kopogni mint az állat

I see why they made a diesel version, because they rev less. I've been thinking of making a wall that helps move the gasses like this, i wouldn't have imagine f1 speeds. Interesting that it's essentially a valve :).

This will create nightmares tonight!

I appreciate your analysis.

Although I do not think this idea will go anywhere, I do applaud the people who divised it. I like seeing outside the box thinking and ways to improve the internal combustion engine. The light bulb did not work on its first attempt either.

( Notes for D-cycle - following are not obvious, call to discuss: 1. Most piston skirts need not be windowed. 2. Ring sections can be made of stronger thin steel just to hold rings and oil to cool. 3. The same rings stop the oil leaking. 4. The piston-train can run directly from the crankshaft. 5. Crown doesn’t run at higher speed and having Atkinson cycle. The full air intake can be provided via an air 2x pump. 6. Valves don’t run at higher speed, except for fewer cylinder engines. 7. Piston-train spring is compressed during intake. )

The cam arm moves the crown piston under exhaust and intake - the easiest of the 4 strokes and so the lightest loading .. really interesting idea .. by changing the timing of the “hop” (the cam timing on the crown piston lifter arm) it would be easy to short stroke the intake (create an Atkinson cycle for better fuel economy) .. hoping development pans out !!

I really had doubts about the title, because there are a lot of KZread channels like "Here’s the techonology of the future!!! OMG [Emote]", also during the 3d animation at the beginning, I suspected that there was more stress on some pieces. But as a result, I’ve really been a hundred years that you’ve been talking about these points, with executably the same skills I thought. This video was really a good surprise, it’s exactly the guy I’m looking for. I’ll follow you and wait patiently for your next videos.

This may hit a roadblock: the cam/follower arrangement simply can't turn very fast before the return stroke on the piston crown starts reducing. The cam would just eject the piston crown

ChrisFix: *makes piston return springs joke D cycle engine: "Am I a joke to you?!"

@repairman22

5 ай бұрын

haha I remember that video. At t he beginning I was like 🤔

I think the piston clashing so fast would demolish the "upper" piston in no time.

@mw2277

11 ай бұрын

you must not think often

perfect application for the scotch yoke

Maybe it is difficult to be realized, because of acceleration concerns and lubrication. But it is a BRILLIANT creation!!!

instead of running it off the crank there should be a smaller cylinder and piston (50-100cc) that pushes the exhaust stroke arm thing in sync with the actual piston. (no spark plug needed, just put a small channel from one of the normal cylinders to allow some hot gas in when it fires).

@theodoremarakas9899

Ай бұрын

What if it was a 4 cylinder engine, two cylinders on 2 cycle and 2 on 4 cycle for balance. If you were to use the same crank

Fascinating!

Looks like the crown piston should be made of a ceramic material, to withstand the high heat problem w/o the need for extra oil to cool it. Ceramics not only withstand heat but also are insulators, preventing as much heat transfer (vs. a metal crown piston) from the combustion chamber to the crankcase.

@stuartwilliams1790

10 ай бұрын

but could it withstand the "clash" when the two parts of this one piston re-connect

@neutronalchemist3241

4 ай бұрын

It seems to be made for diesels. There the speed problem is greatly reduced, since diesels can't rev high anyway, due to the time required for diesel fuel to burn. Diesel combustion is colder than gasoline one (higher decompression of combustion gasses cools them) so solving the heating problem, direct injection works better for diesels than for gasoline engines, and blow by is less of a problem.

How high will the acceleration of that piston be? Maybe works at low revs, but never at higher revs.

@ImWatchinYou

11 ай бұрын

I was going to say this too. It will break down after not too long due to this sharp cam producing such high stress. And the vibration would probably be high as well. Of course it is going to get more horsepower due to half the cycles, but it will surely be offset by the lower RPM and higher fail rate

I imagine this added complexity and subsequent additional moving parts will add to wear and tear significantly. Interestingly though, it might be useful in race and drag engines where engines are typically rebuilt after each use.

What I love is that you assume that the upper part of the piston will come down by itself, which at that point in the 4T cycle is impossible. It's not the atmospheric pressure that's going to make it come down; on the contrary, it's the piston that sucks the fresh gases into the engine, and there are no mechanical parts to make it come down. With a desmodromic operating principle on the cam that allows this to work, it could work, but certainly not in this configuration.

You don't need the second cam to lift the crown piston. You could just have the rocker arm on the second cam ride the crankshaft with a second lobe attached to the crankshaft for the rocker arm on the second cam to ride along

@tdranger6888

6 ай бұрын

It would be a big cam. The return spring would be concentric on the cap rod, and a cap needed on the skirt to seat the spring. But the cap lifting lever, a high stress part, would be eliminated.

Ingenious!

In essence, this design splits the pistons into two parts: One part (crank, camshaft, and piston skirt) that all run at same speed. A second part (piston top) runs at twice the speed. It is evident from the animation that the piston skirt makes its trip once every crank revolution. But the piston top makes its trip twice during that time. So at 1000 rpm the piston skirt moves 1000 times, crank runs at 1000 rpm, and camshafts runs at 1000 (instead of 500 as in conventional engines), while the piston top moves 2000 times. The reduction in spinning inertia (mass @ speed) is basically the source of its advantage. However, complication & added reciprocating parts are its main enemy. An extended test over time is needed to clearly identify pros & cons of this new design, not just building a testing sample and demonstrating that it runs.

Amazing!

Excellent analysis of a fascinating concept.

Developer: it is not durable but... Cars manufacturers: shut up and take my money

Very interesting. Be cool to more on alternative engines 😊

As mentioned in the video and in comments, the accelerations and thus forces required to actuate the auxiliary piston are enormous. There’s probably a better trajectory (displacement vs time) than what’s illustrated in the video. Decades ago Mercedes Benz raced a car with a desmodromic mechanism driven by a circular cam lobe - eliminating jerk and higher order accelerations. But that mechanism had serious overlap which meant the engine could not run well at low rpm. It won races, though.

A separate crown piston crank instead of a cam would be more reliable. Turbo/supercharger's solve the partial charge air intake issue.

My first question is why? We had a 2 stroke engine decades ago already that didn't utilize a total loss oil system. The Detroit Diesel. It needed a supercharger to force air through the cylinder at a fraction of a bar over atmospheric (some used turbos as well in the later years to introduce true forced induction), but was a 2 stroke combustion cycle with 4 stroke valves, crankcase, and combustion chambers. Especially with direct gasoline injection and modern turbos and superchargers, this could very easily be implemented on modern gasoline engines rather than this overly complicated destined to fail design.

Superthanks!👏

I bet it sounds amazing

i feel like some form of super charger would get about the same effect with less vibration. funky idea though.

very good thank you!!!

Connecting rod peak load is actually at top dead centre - the tension needed to bring the piston to a screeching halt and pull it back down the barrel. Its worse on the exhaust stroke (of a 4 stroke) with little gas pressure above the piston to assist the process.

nice vid!

This is the first time I am hearing of this technology. Great presentation! I wonder how it would do in large, slow turning applications such as Marine Diesel propulsion systems? I know most of the largest engines are already two stroke. Perhaps it would just be unnecessarily complex for any gains to be had.

@Velktron

11 ай бұрын

That's exactly the problem with all of those modified post-Otto cycles, including Atkinson: they don't translate well to smaller displacements,/powers because of the added weight, and where weight is of no concern (like large marine diesels) they likely won't offer any significant efficiency or power gains. They only make sense in s very specific HP/weight/rpm zone occupied by economy/high efficiency passenger vehicles, and only when emissions/fuel economy goals must be met with absolute priority.

One point: there is enough place to increase the mass (=thermal capacity) of the piston itself, so that point can be easily improved. But still - the main question is if we really need this technology and is it financially reasonable, not only in the development ohase but also in repairing costs.

It's surprising, that this concept makes more Power, even with the added Camshaft for the Piston...

Even though this seems highly unrealiable, I would still enjoy very much to see a working engine with this setup.

This could work well on a stationary diesel that aims for constant rpm like a generator but you'd have to adhere to runtime maintenance intervals or scheduled services, whichever comes first. Big diesel generators can spend a long time un-started so they need to be test started on an interval (back up generators) but they can also do constant runtime in service (locomotive). Large boats in the other hand generally can tolerate having at least one generator out of service and ships usually double that (redundancy while one is being serviced by the ship's engineer).

now is the time to talk about the infernal noise that this engine would make

It is an interesting concept and I think it has merit. There are some kinks which need to be ironed out, but I could see this being used commercially.

As someone on KZread once said: “Aawwww that's nifty” And another said “I want dayt” Awww that looks so weird!😂 It looks positively twitchy🤣 8:14

There are so many six stroke engine types that also try to combine the benefits of 2 and 4 strokes and they need less parts like the Griffin, Färber, Bajulaz, Velozeta, NIYKADO or Crower engine. Can you show the difference? Thanks, love the channel.

You've heard of Valve float, Now get ready for PISTON float!!

7:26 Ahh… yeah. Piston return springs are needed.

@RobM184

11 ай бұрын

Seems like this engineer went a long way to make that joke a reality

Super thanks

Timing belt: **jumps** Engine: **fucking explodes**

Super.

Nice video. I wonder about the upper crown stability and the chance of it shifting in the bore.

A very intresting engine design. Right now I dont think it would be able to be sold in cars but maybe in the future when its more developed.

That Lil cam lobe shooting the piston up at the bottom of the stroke. That's gonna need to be built tough or be a grenade

Qué maravilla de producto! Ojalá algún día podamos hacerte llegar uno de nuestros equipos para que los evalúes así. Abrazo grande!

I am surprised that there is only a 20% gain in ideal test conditions, considering the real world applications would be subject to the increased potential problems when considering the added complexity.

Let see this GP motorcycle racing first!

I don't think this design would work for vehicles, due to the wider RPM band needed. The challenge with the double stroke is getting the crown piston to drop to bottom dead center on intake. In order to achieve higher RPMs, something has to bring the crown piston down hard and fast, and that is going to take a lot of force that is never returned. It would end up working like jake brakes. Additional force is required by the crown piston to expel gas, then additional force is required by the crown piston to draw gas in. Low RPM generators might be an application.

Maybe a good generator design. Can tune to a fixed rpm. Better torque for sudden loads starting. Can overbuild high wear components since weight is less a issue and normally low run hours will help. This won't be in a cheap residential unit but if it keeps good efficiency and size it could be a fit.

nice idea , especially for diesel !

i can only imagine the absolute racket that thing is gonna make while running. the piston crown connecting back to the skirt, the crown arm running over that highly aggressive cam as well as the more aggressive valve cams. that thing is gonna chatter like hell especially when it gets up in the rpm range. valve/cam float is going to be a huge issue for that extra cam and it will likely beat itself to bits i would say

The cams would move at the same speed more likely 80% the speed of a 4 stroke. The engine would only run at half the rpm of a 4 stroke, and they 80% slower if it's really 20% more efficient. With a turbo, you might not even need a physical device to push the floating piston down. The turbo pressure would push the piston down with air pressure.

This look ridiculous but it's kind of genius. The engine will be heavier than a normal 4 stroke, but it has potential to achieve 2 times the power at low RPMs at least. Balancing might also be a nightmare.

An engine that works and an engine that works reliably over a long period are 2 very different things.

This engine is a novelty that will go into the dust bin of history. The TS3 Commer was a far superior two stoke that was built to last.

@urk5204

9 ай бұрын

I don’t think it’s even real. Stinks like a Kickstarter scam

漲見識了，謝謝分享

This probably would suit a diesel as a diesel will get by on low revs and already has stronger built engines that because it's built for higher compression ,ied love to see this engine built and tried out , surly it's better than electric right now because there no cheeper to run than conventional fuel if you do a lot of miles like I do

Looks to me there are more negatives than positives, great getting more power for the same fuel consumption but the reliability could be the kicker, nobody wants the risk of catastrophic failure

As a mechanic, I can say that this engine is incredible but it will be a pain in the but when replacing the connecting rods lol

Pistons have skirts because they have to have skirts. Race engines have short skirts and are rebuilt constantly, daily drivers have long skirts and run for more than 200k miles. The top part of the piston has to have support with a sleeve or a couple of pins going into the lower part so it acts like a skirt.

So finally the piston retreat spring materialized 😂 At least in Germany and around piston engine guys, this had been a common joke for a long time. But sure, we pack it into a single word: Kolbenrückholfeder

nice... really nice... now let's see if it can take any load or rpm at all. best case scenario, this might become a very efficient engine for some specific edge cases like a generator...