The 5 stroke engine with water injection // Tested in Golf MK5 🤯

[@arba71]

An additional process (the second expansion) doesn't make this engine a 5-stroke. The intake and exhaust are overlapping, so whole cycle still completed in just 4 strokes.

[@JWQweqOPDH]

True odd-stroke engines are impossible because a stroke is either a decrease or increase in volume and you have to get back to the original state.

[@DarkIzo]

imo if its not 4 stroke then its 6 stroke at best usual 4 stroke into expansion and afterwards exhaust, the optional water injection is part of the expansion stroke.

[@RichardLewisCaldwell]

There are two cylinders. Thus, there are 4 strokes + 2 strokes = 6 strokes, but two overlap, giving 5 stokes. The process takes 5 strokes: Intake, Compression, Power, Transfer&Power, Exhaust. "Strokes" relate to processes. This gets more complex and debatable when two different RPMs are used, such as in the engine I'm developing. The induction pistons runs at 1/2 speed, so the engine has eight strokes: Intake, Intake, Compression, Compression&Transfer, Compression, Power, Transfer&Power, and Exhaust.

[@jimmyjames1807]

no this is not a5 stroke motor, and you can get a 4 stroke single cylinder engine, i would believe you that this a 5 stroke engine but we would both be wrong@@RichardLewisCaldwell

[@prdoyle]

I suppose it would be six strokes from the perspective of the fuel/air mixture.

[@gabrielcoelho2346]

This is just like a compound twin expansion steam engine. The engines on the Titanic had three expansion cycles

[@sillysad3198]

and then you add a free-floatin turbine to the exhaust and a sterling to the heated body.

[@Rose_Butterfly98]

Or really just like any steam engine. There aren't exactly any cylinders that do combustion in a steam engine after all.

[@theworkshopwhisperer.5902]

It's fascinating how technology goes around and comes around.

[@dancho0012]

And look what happened to that

[@gabrielcoelho2346]

@@dancho0012 The turbine powered, Lusitania didn't fare that much better😅

[@ferrumignis]

A compound engine using the same double expansion design (three cylinder with the centre being used for additional expansion) was built by the German Deutz company in 1879. A five cylinders compound engine was built by the Frenchman Forest-Gallice who patented in 1890. Rudolph Diesel, father of rolling coal patented his three cylinder double expansion engine in 1897. Edward Bales of Illinois patented his three cylinder compound engine in 1897 The three cylinder Crossley-Atkinson (of Atkinson cycle fame) compound engine was patented in 1903. These designs all suffered the same problem as the one in this video is likely to suffer; the loss of heat from the gases being passed from the high to low pressure cylinder coupled with the additional friction of the additional cylinder negated the efficiency benefits. Gerhard Smith was very late to the game.

[@RealCadde]

And all of those ideas came from the steam engines of the time. With a small piston for HP steam and a larger one for low pressure steam. Even steam turbines work on this same principle, but with less mechanical parts.

[@joejoejoejoejoejoe4391]

The FIAT twin air engine is the only practical way of using an Atkinson cycle engine in a vehicle, by using it for only "part throttle".

[@Volvith]

There we go, i was wondering why this wasn't thought of before, as it's effectively just an in-block turbocharger in piston form, connected directly to the crankshaft. Makes sense this idea is about as old as the concept of super/turbochargers. It's just more power instead of more air, after all.

[@agt155]

@@joejoejoejoejoejoe4391 Loads of hybrids use Atkinson cycle engines.

[@joejoejoejoejoejoe4391]

@@agt155 So to make the usual Atkinson cycle engine you have to add a generator/motor, 1/2 a ton of battery and a load of control electronics, that all add expense along with the weight. Because the valve controlled FIAT system can instantly go from Atkinson cycle to Otto cycle, it can provide both high and low power efficiently, without having to add a motor and battery for low power.

[@MichaelOfRohan]

I just came from the wiki. I want to quote the cycles here, and offer a criticism: 1, induction 2, compression 3, power 4, exhaust expansion 5, final exhaust Thats fine, if all the cylinders moved in parallel. When the final exhaust is the expansion cylinder going upward, that would imply that the power cylinders are going downward at the same time. So cycles 1 and 5 are effectively the exact same cycle. Its still a 4 cycle engine, with an expansion cylinder. Not a 5 cycle.

[@andyharman3022]

They don't call it a 5-cycle engine. They call it a 5-stroke engine. Intake, compression, expansion 1, expansion 2, exhaust.

[@riduck]

The double speed cam just looks like extra complexity, why not a common shaft with a double lobe profile

[@floriancernescu]

The animation shows it spinning at the same speed, or am I seeing things?

[@richardtheweaver4891]

You’re right. It is “silly”. But buying rather precise parts is easier than designing and milling custom parts. The same reason the four-banger was altered to be a two-banger with a klugey re-expansion ‘cylinder(s)’.

[@critterIMHO]

Good idea.

[@mattdaddy_888]

They could also just add two lobes insted of one on that cilinder instead of making it spin double the speed.

[@ulasgursoy2838]

This is essentially an atkinson/miller cycle engine with two pistons, but with the vibrational balance of a four piston engine. The "extra moving parts" problem can be fixed by simply increasing the lobes on the camshaft, an extra camshaft and gear/chain mechanisms are not needed. The current miller cycle engines are limited by the stroke of their pistons; to make the expansion stroke double the length of the compression stroke, you can only use half the stroke for intake, limiting your power greatly. This engine solves that problem in a very intelligent way. I would have loved to see further development for this, I think there's incredible potential for high performance and high efficiency engines here. With enough funding it could start a sports car Renaissance.

[@Appletank8]

I'm not convinced this actually solves the limitations of the Miller cycle. You're going from 4 partially filled cylinders of air to 2 full cylinders of air, which isn't really allowing you to get more air when you're still moving 4 cylinders of mass around. Also, instead of over expanding within the first cylinder, you're wasting some energy going through the transfer pipe.

[@ulasgursoy2838]

@@Appletank8 you are correct, however the video claims 130 horsepower out of 0.7 liters of displacement. In theory, you can use a pseudo v8 configuration with larger cylinders for some crazy power with the fuel consumption of an economy car

[@Appletank8]

@@ulasgursoy2838 Is it really 0.7 L of displacement though? It's still carrying around 4 pistons of weight and friction, and it's practically unusable at low RPM. It wouldn't be that far off from a 1.4L engine expelling half of its intake. A similar engine is the 1.5L M15A-FKS, which gets 123 HP at 40% efficiency, and is usable across all regular RPMs. I'm not seeing that much advantages in this 5-stroke engine here, unless they have an efficiency chart that points out its efficiency range.

[@meta5291]

OK. Thanks for the info. So is this going to be good on all parameters for an ordinary consumer level car - cheaper, better?

[@Thinginator]

Yeah I'm thinking if it "only improves efficiency under high load," then like... just make a high-revving lightweight version for sports cars, where its drivers will be happy to rev it to the moon and get decent fuel economy doing so. Economy sports cars would be fun.

[@phinok.m.628]

2:49 That seems kinda unnecessarily complicated. Why not use the normal camshaft with double lobe cams to achieve twice the actuating frequency?

[@michaelbuckers]

Like others said, it's basically a double expansion engine. It was sometimes utilized in steam engines, but mostly not: if you pull back the johnson bar, this allows steam to work by expanding inside the cylinder instead of just pushing the piston with its pressure, and so by the time the steam is exhausted there's simply no pressure left to drive another cycle of expansion. In other words, double expansion only allows for more efficiency at maximum power setting, and doesn't do anything otherwise. That's fine on a power plant or a sea-faring vessel, but in motor vehicle applications you don't usually even use the maximum power setting, and the added complexity and weight isn't worth the benefit of slightly reduced fuel consumption when you're pushing full throttle. Which is why this extremely old technology which is also a no-brainer to add to a piston-based engine haven't found its way into production cars and trucks. In ICEs specifically there's an additional array of problems such as carbon buildup which can't be self-purged from a cylinder that never burns fuel.

[@GarrettMedicFennec]

Well thought out, I hadn't considered the carbon in the expansion cylinder, it would be like a gdi engine's valves not having the fuel flowing across them to clean them.

[@richardtheweaver4891]

Good point. Fortunately, using a piston-topper to segregate the hot gasses from the piston allows surfaces to run above the temperature where carbon buildup occurs. “Engineering Explained “ has a good video. Search “Italian tuneup”.

[@billymanilli]

I like to pull back on the old johnson from time to time, myself...

[@rebelusa6585]

This engine only work at maximum throttle, should fitted to a race car, should see some benefits.

[@Gnerko123]

The animation is off, the exhaust valves of the middle cylinder should open every time the middle cylinder rises, they now only do so every second time the middle cylinder rises. The voice over says the middle cam rotates twice as fast as the normal cams, but the animation shows it rotating at the same speed.

[@Look_What_You_Did]

Ahh yes. The text to speeh. That's how you know it is quality, and accurate.

[@megab33tz]

I would be interested to see how this compares to a turbo 4 stroke. With the added points of failure and rebuilding of a crankshaft, it seems like a tall order when compared to current forced induction methods. The concept is interesting, regardless, and the video well put together.

[@Drmcclung]

We don't make these because the exhaust strokes themselves (the upward motion of the 4th cycle) of the smaller cylinders are what drive the 3rd piston, not just expansion alone.. you'd need a LOT of wasted expansion from the smaller two to get any meaningful power out of the 5th stroke.. if you're wasting enough expansion on your power strokes to drive a whole separate 3rd piston as a 5th stroke without any frictional and inertial losses, I still don't see any advantage other than packaging. It's kind of a silly proposition. This is basically a turbocharger turned inside out. And you're far better off with that turbo, which is essentially doing exactly the same thing but in a much more effective manner; Harvesting the wasted heat energy from exhaust gasses.. Without the extra friction and inertia loading of an internal 3rd-piston 5th stroke

[@halvaraspegren7635]

Exactly, this also adds a lot of unneccesary weight and moving parts needing to be balanced with even more moving parts.

[@pierrevilley6675]

Yeah, but a turbo doesn't drive the crankshaft, it just decreases the energy from the compression stroke necessary to compress the mixture to the desired compression ratio. So i don't think this engine on its own is less efficient than a conventionnal downsized turbo 4-stroke, but if you add the fact that an additionnal turbo on the 5-stroke takes further advantage of the residual pressure in the exhaust gas, you could potentialy have more efficiency. And the final advantage is the water injection : turbo and/or 3rd piston are not very good at recycling heat (as they both use exhaust pressure), whereas water injection is, making the engine even more efficient. Of course, as water injection cools the cylinder, it decreases the pressure of the exhaust gases in the 3rd piston and the turbo (thus loosing a part of their benefits), but there could still be a net efficiency gain, especially if you use highly heat conductive materials to drive the heat from the power cylinders to the 3rd, in order to recycle it more. Other ways to achieve this could be to make traditionnal turbo 4 stroke engines, but with the 2 center pistons dedicated to collect the heat from the two others (they would only be injected with air/water mix), which would then allow the motor to use the two steam pistons as coolant, instead of a pump driven radiator, and allow the water to be condensed and recycled as their exhaust would be only steam and air.

[@richardtheweaver4891]

Turbines are less efficient than pistons.

[@PRH123]

Very clever, it's easentially it seems to me the same concept as the power recovery turbines on the wright turbo-compound radial engines, where the exhaust spun a turbine that turned a shaft and put that power directly back into the crank...

[@jiroyamamoto2878]

yes, it is a compound engine but using a piston on the crankshaft. Also, similar to steam engines.

[@James_Rivett]

Its basically a internal combustion engine version of a compound steam engine. very interesting video.

[@rob5944]

First thing I thought when I saw the diagram was a steam triple expansion engine, which is suppose this is a variance of...Speaking of which, couldn't said steam on the water injection be recycled, again such as the old ship engines did?

[@andrewlace]

The concept of running an extra camshafts seems a lot harder that simply putting a double lobe for the centre piston

[@DSP990]

That's a genuinely clever idea.

[@stephenbrown2223]

I thought the same thing

[@oskarrabelius7384]

The exhaust gases need to still have enough energy to keep the after treatment hot. Otherwise it can never pass the current EU6 and defiantly not EU7 requirement. There legislations are actually extremely hard to meet even with a regular 4-stroke engine!

[@bvcvcc1289]

@@manitoba-op4jx yep, and egt regulated by amount of water injected

[@1FreeSelfGoverningAmericanMan]

Thanks for that bit at the end about compounding a standard 4 cyl engine. I had thought about doing just that but was unsure if it would be worth while. This just saved me a bunch of time.

[@AnunakiAtlantis]

Thank you for this video. As engineer i saw weakness at this 5 stroke engine. its make me have new idea to make it more powerfully and efficient.

[@Ansis99]

Hi! Some years ago I made water injection system on my VW Golf Mk2. No fuel economy. For right operation this setup needs control temperature of the engine before we can inject water, because if engine temperature is low, we get situation of no combustion/ motor stops. In F1 engines in old days they use water injection only in extreme temperature/ pressure/ knock prevention situations. This thing works only as engine horsepower booster when engine is hot. Be happy! :)

[@svendittmann3105]

I used ultrasonic fog in a TDI! 0,2 - 0,3 l water p.h. - 0,5l/100km Diesel smoother engine run better accleration less carbon pollution

[@pjay3028]

​@@svendittmann3105you should have tried scotch mist.

[@martinklug3701]

​@@svendittmann3105what device did you use to produce the fog?

[@jiroyamamoto2878]

Water injection works for controlling combustion in very high cylinder pressures, resulting from high compression or high boost, or both.

[@Ansis99]

@@jiroyamamoto2878 Yes. For me - in my setup - it works very fine in very hot summer time when asphalt reach extreme temperatures. Lean mixture and cold water mist temperature makes it ideal conditions for clean/ humid/ powerful combustion - engine inside and manifolds was clean always and it gives very quiet engine work. If there is Arduino between all that parts and if it is controlled everything - it will work fine - beautifully! My system was not so advanced and it blows up in one day :)!

[@drewmurray2583]

so you made an engine that can run on water, sort of, but water costs as much as fuel? Did I hear that right?

[@skitidet4302]

It's because you don't just need regular water but distilled water, as using regular water with lots of impurities in it will ruin the cylinder real quick as mineral deposits starts building up on the cylinder walls.

[@The_Lincoln_Penny]

Volvo Trucks have a feature on their 13 liter engines called Turbo Compounding that recovers some of the heat lost during the exhaust stroke without resorting to a fifth stroke. After the exhaust exits the cylinder and goes through the turbocharger, it then goes through an additional turbine. This turbine directs some of the usually wasted energy to a gear link that drives the crankshaft. This significantly increases fuel efficiency .

[@KyleMHeins]

It's a double expansion engine, similar to what was used on 1880's naval vessels prior to the triple expansion engine, which is an option here as well. The biggest difference is where the heat is generated. On a steam engine it is created before intake, while on an ICE it is generated after intake, with the extra step of compression.

[@rosso45]

Adding a water tank next to a fuel tank is a lot weight increasing. The solid carbon residue in the exaust piston may create an issue.

[@thematt6705]

The next time my head gasket leaks I'm gonna call it "water injection"

[@MILELONGJOINT]

🤣

[@youtubebrez1958]

Toyota hybrids operate on the Miller-Atkinson cycle; they just close the intake valves later to make the expansion longer than the compression with good efficiency at low speeds. No need for an extra cylinder :)

[@paulanderson7796]

Americans are very good at "inventing" things thirty years after someone else invented them elsewhere.

[@mnshp7548]

its so similar to a steam engine, a double expansion or triple expansion, where a small piston initially has the high pressure, then a second piston (much larger ) has the exhaust of the first cylinder, which would otherwise be wasted

[@rickhalverson2252]

Also, the expansion piston could be coated to retain heat. Something you don't want with a normal shiny aluminum piston. As that leads to pre-ignition under normal conditions. But the expansion piston, if it retains heat, would be more efficient at converting the water to steam instantly.

[@archygrey9093]

They make it sound this this is a new design or development, I remember researching about this when I was a kid about 15 years ago. Still a neat design, has definite potential for stationary engines and generators

[@yannaigolan916]

This channel has no business being this small. These videos are so good I wait for them to drop all the time

[@fastinradfordable]

Also as a vw /Audi shop owner from 2010- They couldn’t have chosen a worse engine. This engine already is incapable of going 100k without wearing out internal components.

[@TheLtVoss]

Probably why they used them a engine near its end is cheap

[@Mladjasmilic]

I have a Fiat Punto 1.2 with 240.000km and no issues yet. My old Daewoo did 270.000 when I sold it. My uncle had Astra F 1.7d Isuzu, which did over 800.000

[@samuelmatheson9655]

STEAM ENGINES ARE BACK BABY

[@hoodedcreeper2465]

You could probably get away with heating the intake with the exhaust since you have the extra expansion. The problem with doing this on regular engines is it effectively increases the compression ratio by increasing the temperature of the air without increasing the expansion ratio. So more work is done to compress the air without actually getting that work back through expansion. This has shown to increase the efficiency of turbine engines.

[@archygrey9093]

I believe heating the intake would decrease the air density leading to less power and the warmer F/A mixture will more easily pre-detonate leading to lesser compression and retarded spark timing to compensate

[@stephenkeebler732]

I remember seeing this very setup in an old Engine Design book from the early 1920s. Same process but it used a standard cam in the block and pushrods driving the overhead valves. I believe the Engine was from about 1915...

[@waitpu4817]

Get rid of the valves on the central piston & just have exhaust ports at the bottom of the cylinder like in the 2-stroke diesel, use a V3 design for more direct flow & shorten the exhaust travel into the cylinder & don't upsize the exhaust cylinder.

[@sillysad3198]

smart

[@rlstnnl1740]

Brilliant

[@sobhansabbagh6171]

I read about this engine on Wikipedia but couldn't understand how it worked, thank you for explaining it , more research needs to be done on it

[@Firefrei]

I think the Argentinian pendulum engine is the best non mass produced engine variant. Oil isn’t required because there is no friction and 100% goes to turning the crankshaft instead of rubbing the cylinder wall

[@pankaj7977]

Very good explanation

[@itskarl79]

Reminds me in similar concepts to the scuderi.

[@peterrosler6822]

1) I doubt the fuel efficency will increase by 40 % (- 30 % consumption) by just using a part of the residual excess pressure (5 bar mentioned). 2) The displacement is 1.5 L as also the central cylinder displaces a volume. 3) What happens at low loads (traffic)? The excess pressure from the combusting cylinders would be much lower, but there is still a need for excess pressure for final exhaust. The middle piston would then "suck" the hot gases (or might provide resistance) ==> Efficiency would go down.

[@murraymadness4674]

Adding a turbo is effectively the same thing as it extracts the energy from the exhaust to create more power, and is WAY more simple than this design.

[@oscarschott8905]

Turbo relies on also putting more fuel in the combustion chamber to accommodate for the increased air density (more power => more fuel consumption). Like the turbo, the center piston uses exhaust gas and pressure difference to operate. However, this engine doesn’t need extra fuel to further assist the turning of the crankshaft (more power => same fuel consumption => more efficient)

[@murraymadness4674]

@@oscarschott8905 while yes it is not exactly comparable, you can just use a smaller displacement engine and get the same power output.

[@Appletank8]

What it's actually similar to are Miller Cycle engines. They expel a portion of the intake in order to have a longer power stroke. This ""5-stroke"" has half the intake for the same "expansion" ratio, or 0.7L of compression, 1.4L of expansion.

[@archygrey9093]

Yes a turbo makes use of the waste exhaust pressure but does so in a way to increase air density and thus more fuel and power, but not efficiency. This design increases the efficiency (and to a smaller extent) and power of an engine without using more fuel

[@archygrey9093]

​@murraymadness4674 True, but the smaller engine will still typically use the same amount of fuel as a larger engine when producing the same hp, they are still burning the same amount of air and fuel the smaller boosted engine is just cramming it all into a smaller space. Thats assuming they are running at full power however, realistically the smaller boosted engine will spend most of its time off boost and thus will be using less fuel than a larger NA engine

[@paulweidler2117]

If you put catalytic converters between the cylinders, such that the exhaust from the HP cylinder goes thru the CC before entering the LP cylinder, that might improve both efficiency and emissions. My 2c.

[@lcambilargiu]

To further enhance efficiency, a catalytic converter can be added to the manifold that feeds the central cylinder. That would add heat to the flow into tue center cylinder and enhance the water injection as well.

[@lordchickenhawk]

Could be tricky to actually pull off with the limited space available over the short transfer port lengths but it makes thermal sense to me. It seems to me that the shorter the transfer track the better. EDIT: Given that the engine is already has a restricted effective RPM range I suspect that there would be an ideal transfer port length that would be able to take advantage of harmonic gas wave effects like a tuned length extractor exhaust system. That may even enable room and gas dwell time sufficient for your catalytic converter idea. The narrow usable RPM range would be likely to become even skinnier though.

[@ddjohnson9717]

To you talking about? Cats don’t add heat to anything, quite opposite it takes away heat and energy 😅

[@lcambilargiu]

@@ddjohnson9717 the chemical reaction that is catalyzed is exothermic. Cats introduce a flow restriction though, thats where they sap performance especially because the extra heat produced is normally always completely wasted. In this twin expansion design though, that energy goes to enhancing efficiency Edit: some people prefer dogs anyway.

[@lcambilargiu]

@@lordchickenhawk the port should be built into the head, I'd think. The catalyzer needs to be an insert that fits in place. If you are converting a 4 banger then maybe simplicity is a better option.

[@lordchickenhawk]

@@lcambilargiu Yeah, I think so too... like I said, space would be the tricky bit, either way. And the flow restriction you mentioned to ddjohnson would present further difficulties. I like your idea but I think it would be very difficult to it pull off in actual practical application.

[@petit_donnie]

Omg just discovered your channel, it's so good quality. Thanks for the sharing of knowledge and making the research job that easy

[@mircomuntener4643]

Lol, no, there isn't a third cam for the center exhaust, there's just an extra exhaust lobe on that cylinder's section, so it opens each time the piston rises.

[@whiskeytangohotel6624]

And now F1 uses a recovery turbine to charge a battery.

[@rientsdijkstra4266]

This is simply a 4 stroke engine with a different managment of input and output of gasses. You can calculate this in two ways. Method A.) (easy) You have three cylinders each of which follows a 4 stroke input and output proces (that is two say 1 power stroke per 2 revolutions = 4 strokes). Method B.) (more convoluted) we only count the HP cylinders as actual cylinders and we count the LP cylinder as a "helper" of wich the strokes must be added to the respected HP cylinders. In that case the middle LP cylinder is dedicated for 1/2 to each of the HP cylinders. Together , for each 2 rotations of the crankshaft, each HP cylinder + 1/2 of the LP cylinder produce 6 strokes, but because LP cylinder uses a normal 4 input and output mechanism, it produces 1 power stroke for each 2 rotations or 4 strokes. In other words it produces 0.5 power stroke for each of the 2 strokes that are dedicated to each of the 2 HP cylinders. So for each HP cylinder we get per 2 revolutions of the crankshaft: 4 + 2 = 6 strokes for wich we get 1 + 0.5 = 1.5 power strokes. But 6/1.5 = 4 so we still have a ratio of 1 power stroke per 4 cylinder strokes... so again: IT IS SIMPLY A 4 STROKE ENGINE! (with a different input and output mechanism for reuse of exhaust gasses).

[@menteko2137]

3:21 a similar system was in the F-80 Shooting Star where water was injected into the exhaust of the jet where the water turned into steam providing additional thrust

[@Drunken_Hamster]

Better to run the second expansion cylinder on something like 1-way valves like reed valves. Also, to combat the loss of efficiency at low load and the lower pressure/energy causing turbo lag, make the second expansion cylinder the same size as the normal cylinders instead of 2x the size. Also make the whole engine in general "under square" for thermal efficiency. Also, for better frictional efficiency, you could make the whole thing a Taurozzi Pendulum engine.

[@edgibbs2794]

Making the second expansion cylinder the same size as the primary cylinders defeats the point. The reason it's larger is because it requires less mechanical force to push a smaller chamber's volume into a larger one. if they were the same size, the force pushing back on the primary cylinder would completely negate any force imparted on the secondary cylinder, and you would run at less efficiency than if you didn't have the secondary cylinder at all because it would just be dead weight.

[@honeydavis5568]

I applied to DARPA with this idea in 1989 and they turned me down. But water injection will not produce more power. This was thoroughly tested by NACA. Water injection raises octane rating in internal combustion, only.

[@repairman22]

Water is injected in the expansion cylinder. No combustion occurs there, so octane rating has nothing to do. Thank you for writing.👍

[@johnh1001]

Good Day : At time about 3:23 "Water Injection" what an excellent idea . To get that clean de-mineralized water , all you would need is a "Water Maker" . These are small and compact and can also be seen in regular use on board Navy ships .

[@SirTubeALotMore]

Fantastic, somebody made a proto of my old drawing from 1991🎉

[@CapnSlipp]

So it uses the pressure of exhaust to turn the crankshaft. So a turbocharger, but instead of that rotational energy going into bringing in more intake pressure, it goes straight into the crankshaft. So really, an inverse supercharger, instead if using crankshaft energy to bring in more fresh air, it uses exhaust to give more crankshaft rotation.

[@paulwhite7475]

Another ingenious solution to an unasked question .

[@nicklaich]

Very nice idea, but. Expansion ratio is already extended by valve timings, reducing power, but increasing efficiency.

[@kevindouglas2060]

Compound engines could maybe have been called new in the early 20th century.

[@gkdresden]

In my opinion you can get the same effect with the Miller or Atkinson cycles. The advantages of these cycles is that you keep the number of moving parts. Using these cycles it is also possible to vary the compression to expansion stroke ratio. So you can operate the engine in the Otto cycle limit for best power and in the Atkinson or Miller cycle for best efficiency. In general, all these engines are much to complex for unexpensive manufacturing.

[@earth9531]

All 3 disadvantages go away in a light airplane installation. Max power nearly all the time, only 1 rpm is just fine, and no need to worry about cytalyist.

[@carllinden533]

What an excellent explanation! Showing all the different models of this idea felt like an adventure! I love the simple conclusions at the end. The friction and complexity remind me of the opposite type of engine used the Sachsenring Trabant 601. Boy I want to see that animated so bad.

[@Volvith]

So it's basically an integrated turbo, but instead of drawing in more air, it's effectively sending the power directly to the crankshaft? I mean it makes sense why this would increase efficiency by a great degree, but this really hasn't been tried before? Same with the water, you're effectively just pulling out more mechanical energy from the heat of the engine, while also regulating thermal buildup better. I guess integrating this into an engine block isn't an easy feat, and especially without the water injection i could see chamber fouling as becoming a problem pretty quickly (since there isn't a compression + ignition stage to clean the bore)... Still i would have expected someone would have thought of this sooner? EDIT: Turns out this is an 1870's concept. Smith is a late bloomer. As in a century and a half late.

[@jeffs.987]

There was an antique car called the Compound that had 3 cylinders and worked much like this.

[@bdkw1]

The have one at the fountainhead auto museum in Fairbanks. It's a runner and they drive it.

[@louisvanrijn3964]

So the patent would be a fake? @@bdkw1

[@MILELONGJOINT]

Kinda must find it :) fountainheadauto.blogspot.com/2012/09/the-unusual-compound-automobile.html

[@jacquesdubord6844]

This engine is very interesting. It shows that there is more researches on the piston engine. Why isn't there more researches on the turbine engine for vehicles?

[@absolutepressur]

Another big drawback is lower power density from mass and packaging perspectives. You still have that big engine, but with the displacement of a 2 cylinder.

[@homoludens07]

Rudolf Diesel tried to design a high pressure twin expansion combustion engine, but he failed. Probably he had to define too many deetails, because it took him 3 or 4 years to get a real working engine.

[@CurtisStewart-si2em]

I love the efforts taken. Hopefully the research dollars will pay off.

[@DO_NOT_HUMP]

The biggest issue I see with this engine is that the central LP cylinder gases it’s cam timing locked to the HP cylinders. This prevents it from having variable expansion ratios, giving the engine only a small band of high power and high efficiency.

[@billkillernic]

Well if you add a small electric engine to handle the low rev states of the car (like the ones found in hybrids such as e.g the Suzuki swift hybrid) I think you can negate the negatives and take advantage of the positives of this engine type

[@ralphvalkenhoff2887]

Thank goodness we still have minds to r&d in our time

[@bobbygetsbanned6049]

The middle piston getting the exhaust gasses without combustion is going to get filled with carbon. Without fuel and combustion the cylinder walls will get destroyed from the abrasive carbon.

[@paulanderson7796]

Let's not introduce science and facts to mess up this nonsense.

[@gilbertko3501]

I have been following this design for over 9 years. Still not in production yet. There must be challanges enginner couldn't over come...

[@Kerman_von_Braun]

The fact that central cil valvetrain has to run at 2x the normal speed basically kills the idea in practice. It might work on small engines, but its not scalable.

[@A2J_Tim]

I run water meth injection, you dont need "demineralized" water, even mineralized water will still scrub carbon off and not leave deposits.

[@chinsta00]

It seems to me that this cycle could also be used in combination with your previously described Mazda 2-stroke engine. In other words a two piston engine design, with the small cylinder operating according to the Mazda 2-stroke cycle, exhausts into the large cylinder using water injection as described in this video. Would that make it a 3-stroke engine? ;-)

[@cromo7743]

Nice idea.

[@DailyLifeSolution]

I am glad to be the first comment writer. I opine that proposed engine needs further funding and research to weed out the problems and refine it. Funding often differentiates failed engines from successful ones.

[@robertcassara1489]

It seems to me that this is what the auto manufactures should be pursuing instead of an all electric vehicle. Range anxiety and the very large and heavy batteries is what is stopping the EV market from taking off. Furthermore, it appears that a diesel version of the 5 stroke engine would be even better for fuel economy and fuel options such as renewable diesel. This is something the greenies should love. There are a multitude of fuel options with a diesel engine. Spark ignition is limited because of the compression ratios limitations and associated pre-ignition problems.

[@mircomuntener4643]

The idea of a small range extender generator will become much more popular very soon.

[@rudyberkvens-be]

Such products say more about the tenacity of the inventor than about the effectiveness of the invention. And in the end it is proved: in general more disadvantages, and the advantage only in special conditions.

[@josepeixoto3384]

That is just a great idea; also, an engine like that almost needs no exhaust muffler, at least way less expensive; it WAS always very sad to me, to see engines exhaust with a BANG,(remove the exhaust manifold, and you'll see...)meaning that A LOT of energy was wasted; For racing, the center Piston can be used as a "Turbocharger", a Blower.

[@alenmonsyedward7499]

Build up on intake cams / ports to middle pistons will be an issue...and if stroke is variable (nissan VC technology)... the low load issue could be solved...

[@yan7911]

if you really want to harness the power of the exhaust gases then just put a generator on the turbo like f1 does, it makes for the best fuel efficiency ICE can reach and can be installed on whatever engine you want in addition to improving fuel consumption at any load due to the fact that you use this power whenever you want with your electric motors I really don't get why it still isn't being used in all the new ICE vehicles

[@Yakjzak]

This is some great invention, but just the fact that it's really useful in high RPM, and consume more at low RPM due to the complexions of the mechanism means that it's useless for everyday use as use our cars on low rpm, ramping it up would just worsen the fuel usage. The way it could be useful is in race cars, which are primarely used on high RPM. Tho the down on power is also something to have in mind, plus the wheight it adds, let's see if it's adopted or tried and abandonned like the sad story of (my favourite engine) the dorit- Rotary engine

[@alvydasurbonas8913]

Its like plane engines that had a ehaust turbo that spun crank shaft via some mechanism

[@fireblow6842]

wat

[@Appletank8]

Those are called turbo compound engines, which is indeed a similar concept. A turbine uses exhaust energy to turn the crank shaft directly.

[@v_stands_for_value124]

3:52 basically water is the new NOS 🤣

[@extec101]

the idea of a turbo that feeds a fixed volume cylinder that then feed the power cylinders with boosted air preasure dont seems like a bad idea as the boost cylinder could be of slight higer volume then the power cylinders making the engine feel like its got torque at all revrange and it feels like a bigger engine then it is.

[@mattperjes6173]

the size of the illmore prototype is not 0.7 L, it’s closer to 1.5 L. They only state it’s 0.7 L because they’re not including the expansion cylinder.

[@856Dropout]

It’s amazing how much volume of demineralized water every building in the country produces

[@MikeJamisonm]

I had a similar idea - but I was thinking oof using a standard 4 cylinder engine custom cams and modified intake/exhaust manifolds. Basically this thing is like the gas version of a 2 stage compound steam engine.

[@craazyy22]

I really don't see how this would be viable. First of all the carbon depoists on the would be a nightmare. Then the friction aspect of the middle cylinder.

[@theangel540]

...The return of "long stroke" engines which is an industrializable compromise and which floods modern engines. The ideal would be to have cylinders thermally insulated with extraterrestrial materials to conserve energy/heat... (very) hot exhaust gases to be effective on a second expansion. The "long stroke" offers cooler exhaust gases.

[@joseveintegenario-nisu1928]

What about the central cylinder valves operating in hot exhaust gases? What about the EU fellowship to Burgundy University to Study the Gerhardt engine? And the antecessors, the Otto double expansion, three cylinder engine; the Eisenhut horseless Vehicle, CT; the Spanish patents by Gimeno-Cataneo; Ubierna-Laciana?

[@starkindustries26]

*steam engine* “you couldn’t handle your failure, and where did that bring you. Back to me”

[@sillysad3198]

you can use "catalyst" BETWEEN the cycles, and it will add efficiency because "catalyst" is exotermic.

[@Pystro]

I had the same idea, but any increase in the volume of the transfer tube decreases efficiency: At the point when the transfer tube opens, you have the high pressure cylinder fully expanded plus the volume of the transfer tube (plus zero from the low pressure cylinder because it is at top dead center). When the transfer is finished, the exhaust gases are contained in the full volume of the low pressure cylinder plus the volume of the transfer tube. Assuming that the swept volume of the low pressure cylinder is twice the volume of the high pressure cylinder (which you probably don't want to stray too far from because of the weight balance of the pistons); If the transfer tube has the same volume as the small cylinder, then that results in a 2:3 expansion; if the transfer tube has the size of the large cylinder, then you only get a 3:4 expansion. Ideally the transfer tube would have no volume, which gives you the full expansion ratio of 1:2.

[@sillysad3198]

@@Pystro i agree

[@fixedG]

I'm not an engineer but could this concept not also be applied to create a three-stroke engine from a two-stroke, significantly improving the emissions and scavenging even greater power from the exhaust gasses than the five-stroke? I imagine the cost/benefit must not work out in that kind of in-between application.

[@yousernameish]

I attempted to patent exactly this, some 15 years ago (totally oblivious that it was aready in development stage, under the title "double expansion / internal combustion engine". I hade the same layout, two smaller pistons either side of a much larger piston. Kinda freaky, but just convergent evolution i guess.

[@robink.9459]

why didn't they put dual cams for the middle cylinder instead of going with a separate cam shaft that spins twice as fast?

[@KarolOfGutovo]

Rather than using so many timing belts, why not just make a cam that has 2 high points and 2 low points for the exhaust on the low pressure cyllinder?

[@hunnybunnysheavymetalmusic6542]

Complicated, but quite logical!

[@hasse102]

And as we all know water freezes at 0 degrees so just an other summer engine. Whenever you start to mix water in there is that limitation.

[@WaldemarHartmann-x5i]

If Hybrid is Standard, this Engine will be standard

[@alexwalker8422]

Perhaps a condenser would provide a surplus of water which could be retrieved from the exhaust. It would be pre heated too.