ALREADY PATENTED!!! - 2 Stroke Engine with Advanced Valve System From Mazda

[@timothykelly7974]

60 years ago I worked on the Foden 6 cylinder 2 stroke marine diesel engine. It was very similar to this concept, using a supercharger and exhaust valve. No reed valve needed. The exhaust valve operated on the kadenacy system which allowed the valve to stay fully open longer for better scavenging. The high profile cam gave the valve a snap shut operation. It was the smoothest running engine I ever experienced.

[@8alakai8]

when in school 16 years old i designd this but at school they said its like a two stroke diesel

[@gaychik9328]

All New this is good forgeten old

[@gatorred157]

ps GM designer of the 2 stroke truck engine found one flaw ( it is it run away at full tilt & run so with no way to shut it off it own oil in the crank case i found this out from there legal team in a court case I was part of) one in a white truck run wide open apart burned shop and 4 building to the ground! i was the last guy out of the shop! before it caught fire!

[@codypendant6745]

@@gatorred157 I drove the '53 series Det. Diesel for a couple years. Never had a runaway. It had a turbo on top of the blower and reminded me of my old 2-stroke motorcycle that only had power when it was 'on the pipe'. Too bad it was targeted for removal from wide use here in the U.S. Great design.

[@vivekpadale4266]

The mazda 2stroke will sound like a four stroke engine with a fast pulse.

[@mike423439]

At 7:30 time mark the video states that in a normal 4 stroke engine the camshaft rotates 360 degrees for every 1/2 rotation of the crankshaft. This is exactly the opposite of what happens. The camshaft in a traditional 4 stroke rotates at 50 percent of crankshaft speed. Using the same poorly described action as the video, the correct description would be, the crankshaft rotates 360 degrees for every 1/2 rotation of the camshaft.

[@richardcloudbase]

I noticed that had had a little chuckle

[@emknapss]

the Supercharger is also rotating backwards.

[@bigjohnl57]

Hard to take this seriously when they get basics wrong

[@Den-ml7zg]

he 100% said the same thing. A 2 -1 ratio.

[@DelticEngine]

@@emknapss Or is the animation reversed?

[@rjung_ch]

Love how Mazda is involved in so many diverse technologies and are trying to reinvent the 2 stroke!

[@Wingnut353]

Mazda and Toyota are some of the only companies actually moving forward with innovation rather than just inventing stuff and sitting on it.

[@marioncobretti7870]

I find mazda tends to just rip off existing things and call it their own. But ill give them credit for actually putting it out in things bigger than lawn mowers

[@phylthamendment]

Now all they have to do is add water methanol injection and hydrogen and now you really got a good concept to get rid of these garbage non green electric time bombs on wheels

[@citizendc9]

@@marioncobretti7870 The Japanese take things and make them better. It is a cultural characteristic of the Japanese and you can see it everywhere from vehicles, electronics to food.

[@davidturner1641]

Except this is 100 year old technology, lol

[@damianking2065]

I've known how a 2 stroke engine works for 30+ years without actually knowing how it works. That is the best description I've ever seen/heard. Thanks.

[@ЕвгенийШикин-п8р]

2 тактный мотоциклетный и бензопильный двигатель работают по другому, там нет нагнетателя, клапанов, распредвалов и нету масла в картере, масло нужно добавлять в бензин чтоб оно смазывало картер, цилиндр и поршень. Эта технология мазды напомнила мне судовые дизели, там точно так же работает двигатель, есть масло в картере, есть компрессор и клапана

[@pubjitsuguy8596]

Omg I was thinking exactly the same

[@73Datsun180B]

this is the most retarded version of a 2-stroke, a petrol Detroit would be much better!

[@Meower68]

Back in the 1980s, Orbital made a 2-stroke engine with a supercharger. The exhaust port was valve-less, on the side of the engine. The intake had a reed valve; as the pressure in the cylinder dropped ('cuz exhaust gasses escaping out the side), the supercharged intake air pressure overcame the in-cylinder pressure and pushed the valve open, admitting fresh air / fuel into the cylinder. Fresh air / fuel in through the top, exhaust gasses out through the lower side. When the cylinder rose enough to cover the exhaust port, the pressure in the cylinder rose and the reed valve closed. It was pointedly setup such that about 2/3 of the (upward) cylinder stroke was compression, about 2/3 of the (downward) stroke was power and the remaining 1/3 of each (near BDC) was overlapped exhaust / intake. Emissions were relatively clean, because there was no oil being burned. Given this was developed back in the 1980s, and Mazda is just adding cam-driven intake and exhaust valves (old news) and direct injection (old news), I'm surprised this was considered sufficiently novel that it would qualify for a patent.

[@paradiselost9946]

orbital" you mean ralph sarichs? and his original engine, both the two and four stroke orbitals, never actually ran by themselves... at some point falling back on a piston engine to "drive" it... yeah, i still got a lot of articles on that particular concept...

[@adrienst.raymond6801]

The longest production engine ever was a two stroke diesel with a crankcase and an oil pan(crazy, right?) It is the 71 series detroit, made between 1932 and 1994. Because a blower was mandatory for the engine to run, the standard engine-with-blower configuration was considered naturally aspirated, with forced-induction classification only given to engines equipped with the blower AND 1 or 2 turbos. The series classification indicates the displacement of each cylinder in cubic inches(ei 53 series, 71 series, 95 series, etc) meaning that to find the displacement you multiply the number of cylinders by the series classification (8v71 -> 8*71=568in^3) truly the greatest engine of its time, it’s fully mechanical, and can be gravity fed if necessary, with no true requirement for pumps(high or low pressure). They didn’t make very much power, they weren’t very fuel-efficient, they leaked plenty of oil, and they were extremely loud earning them the nickname “screamin jimmy”, but dammit they were probably the most reliable engine of the century, alongside the 6BT.

[@ronaldrussell5481]

I loved selling Cummins against them!

[@JRotten]

Actually the 12V series made a bunch of power. Especially in boats, when they added twin turbo chargers to the mix.

[@jlo13800]

Yeah i hate oil injection sump mounted on a detroit and like dry sump oil injection much better. The Rotax 850 Etec turbo r and Cummin ACE OP 2 stroke are like this.

[@SlickWilly79]

A dude on the tube just made a common rail Detroit powered drag truck, makes some real power

[@jlo13800]

I have an silver 8v92 out back and i run BRP XD-100 Etec 2 stroke oil in the bottom end, some is pulled off and mixed and i add more. I like arcticat new 858 engine and if were scaled up to the same size of the 8v92 it would run right over it!

[@tomsmith2209]

I like that Mazda is willing to walk a different path to other companies.

[@Bluecedor]

I agree, though I think the most significant reason for that is they are the smallest large manufacturer not owned by someone else. Toyota hasn’t just up and purchased them yet, and eventually the car market will reach a critical mass where Mazda’s offerings will just be drowned out and they will fold due to lack of sales. Their best strategy is to start demonstrating their engineering chops so that another larger company will want them not for their product line, but for their patent portfolio. Nissan already proved out variable compression, so I imagine Toyota will want to hug whatever patents Mazda comes up with nice and tight…

[@MrPaige222]

Mazda should have abandoned the rotary engine 40 years ago instead of doubling down on stupid. I wouldn't trust anything from their "engineering " department until they can best their competitors in efficiency and longevity. This will probably not ever be introduced into a real car. Too expensive to produce and unknown reliability as well as efficiency and performance. Nobody will buy it because MAZDA has proven itself as a poor performer.

[@BurnerJones]

@@MrPaige222 all you do is complain

[@MrPaige222]

If your definition of complaining is observing and speaking the truth... Then in your mind I guess you have a point.

[@kopronko]

@@MrPaige222 Yes, that Rotary engine was a missmess , But Lately, Mazda Has Proven their Technology with their SkyActiv technology, so, now i Would also buy new Mazda , as one of my friend already bought it, and is very happy with it. And, i would also dare 2 buy This New engine in some new Mazda.

[@cat275hp]

It's amazing that Mazda created a backwards spinning supercharger!

[@timfeeley714-25]

It's called the reverse flow engine, amazing huh!😂

[@petermoses8518]

Somehow people think that stuff is squeezed through the middle rather than the outside. I recall even a master-mechanic explaining the oil-pump that way (the oil being compressed to a volume of almost zero) @@timfeeley714-25

[@josephrheaume8386]

And that air intake is on the same side for both parts of the supercharger

[@jonrice21]

@@josephrheaume8386This design actually pulls air from the exhaust and blows it out the air intake. It's revolutionary.

[@stevep8490]

​@jonrice21 the pressure at the valve from the super charger just has to higher than the cylinder when the valve opens.

[@PSDAndre]

I had the idea when I was fifteen. I then discarded it and replaced it with a more suitable DC principle. Inlets at the bottom like on a conventional two-stroke engine and electrically controlled exhaust valves at the top, resulting in a wide usable speed range. This also makes it possible to work with boost pressure. The exhaust gas is used to generate electricity via a turbine with a generator. Although this increases the exhaust back pressure, it hardly slows down the piston as the connecting rod is almost vertical during exhaust (no leverage). Ceramic pistons and cylinders eliminate the need for lubrication. In sliding mode, the engine can act as a compressor to drive the turbine due to the electrically controlled exhaust valves.

[@geemy9675]

I think there is potential for uniflow injected two stroke like you describe. similar to two stroke diesel but leveraging modern variable valve timing and lift and working at higher rpms/power with spark ignition. the turbine/compressor configuration is an electric turbo charger with no mechanical connection beetween the turbine and the compressor. I think its is more efficient to maintain the shaft between and use a motor/generator to control the turbo speed. (regen when the turbo wants to spools too fast, motor when the boost is low and you need more torque. ideally you would have a clutch to disconnect them when you want different speeds on turbine and compressor side, and reconnect them when you want the turbine to drive the compressor as efficiently as possible, but I dont know if its possible to implement a reliable clutch without adding too much weight ? elzctirc valves could help but they dont seem to work outside prototypes. freevalve has been around for basically two decades now and still nowhere to be found in any production car. even the Gemera's promisef TFG freevalve engine seems to be discretely replaced by a traditional V8. I was a firm believer in this technology but if koenigsegg cant make it work in a multimillion dollar cars, I dont rhink we'll see it on the roads. But it is nit necessary now with modern advanced variable valve timing and lift. same for ceramic piston a'd culinder walls. in theory it could benefit any engine but manufacturing, reliability etc..

[@pauljcampbell2997]

Great idea!

[@73Datsun180B]

why would you want to make electricity with exhaust instead of alternator and have exhaust driving turbo making boost?

[@geemy9675]

@@73Datsun180B it's like turbo vs super charger. exhaust gas velocity is "free" energy. taking energy /torque from the crank is less efficient and doesn't produce as much power in the end

[@73Datsun180B]

@@geemy9675 but my car with 500,000km and sweet fuck all compression anymore, only loses about 40rpm at idle with ALL the accessories on including high beam and a/c! Turbos are for making more power lol, not driving an alternator. You are going to get turbo lag which is fucking gay. Maybe your setup will work in a constant rpm situation, but I think no good in a vehicle.

[@mrsamskey]

Supercharged 2 stroke diesel. I designed one as part of my dissertation in 2003. However, I withdrew it because I didn't want the university to own the idea. I then spent 20 years bankrupt and floundering whilst I try to develop the idea on my own. Now optimise the torque curve to a hyper efficient narrow band, and use it to charge full electric transmission. Similar to an old Kawasaki train, except with battery storage.

[@eclipsegst9419]

Ew no. Make it a V8 and connect it to a Tremec T56 and do 10K rpm burnouts!

[@RhumRunner41]

Edison Motors is doing just that with looking rigs.

[@randykubick]

Truly amazing how well these new engines work in CAD.

[@rafkazdakirkhafadi2441]

Its different. The engine that you mean, its has hole on liner.

[@jamescampbell4334]

So true. This one is working with the blower rotors spinning in the wrong direction.

[@MadScientist267]

This has got to be one of the worst explanations of engine operation I've ever seen

[@MadScientist267]

@@davehart7943 We got it fine 🙄

[@MadScientist267]

@@davehart7943 Your bus must be so short it runs backwards 🤦‍♂️

[@mickvonbornemann3824]

Nothing new here, it’s been know for a century that adding a supercharger means crankcase scavenging isn’t required, while poppet valves have also been used on certain 2 strokes for a century too. Look at 2 stroke aero engines for some examples

[@villiersman951]

👍👍

[@carlosbonifacio825]

GM had poppet valves on their 2 stroke diesels and a supercharger. Powerful and reliable engines.

[@americanrambler4972]

@@carlosbonifacio825and very noisy!

[@ATomRileyA]

@@americanrambler4972 But also awesome :) kzbin.info/www/bejne/oYPdmoZseJicZ7M

[@KrustyKlown]

Right, but those engines don't have an inferior scavenging system like this Mazda engine, that leaves 1/2 the exhaust gases in the cylinder which makes it impossible to accurately control the fuel air ratio, thus running it too lean or too rich ...over heating & emissions will be a problem.

[@patrickshaw8595]

1n 1978 me and some friends put a Shorrock blower on a Kawasaki KZ900 engine. it had too high of a compression ratio to really use much boost effectively. So we changed sprockets and made it's dual overhead cams turn 1-1 with the crankshaft. Started right up using a Weber carb in draw-through mode. Didn't like to idle down or run slow. Made great drag strip power but longer runs made it overheat. Fuel consumption was ridiculous but we didn't try to measure it.

[@ManiacRacing]

Yeah, no you didn't. Lol. Stop lying

[@dubsydubs5234]

And you didn't modify the ignition?

[@SmeurkeDeKat]

@@dubsydubs5234 If it's wasted spark ignition, I believe you don't need to.

[@dubsydubs5234]

@@SmeurkeDeKat True.

[@jlo13800]

You made it into a 2 stroke!

[@LOLINC2010]

Somewhat simple, yet totally brilliant design. I love engineers that come up with great stuff like this, and love the companies that support them.

[@CAPTIVEPULSEMAKER]

kzbin.info/www/bejne/iYqohoaiZ9uioqc

[@CAPTIVEPULSEMAKER]

kzbin.info/www/bejne/iYqohoaiZ9uioqc

[@geemy9675]

like most simple designs it's already been tried. Ferrari did it 30 years ago and people probably thought about it a.vzntuey ago. the question is can it work better with modern variable valves. seems like it could work better with an electrically assisted turbocharger that is not driven by a constant gear ratio and can be controlled

[@berfava]

Amazing video. I'm a mechanical engineer and I wish they had your video 15 years ago to lecture about engine specs when teaching thermodynamics cycles theory

[@Bluecedor]

An interesting phenomena to observe, the way gas engines keep edging ever closer to basically being diesel engines but with a different refinement of crude.

[@TurboTaco2JZ]

They are getting closure to diesels including the need to having a particulate filter (mandates coming soon to the EU)

[@eonreeves4324]

@@TurboTaco2JZ all that is horse shtt anyhow, ask them what percent they wish to bring CO2 levels down to, first of all, they don't know. second, they don't know. it's a fkn scam and we need to call it as it is, globally. fk the overlords

[@huangGQ]

It's mostly our attempts to approximate the Carnot cycle while also generating useful amounts of power.

[@Blanchy10]

Despite popular belief two strokes don't rev high, for any given engine size they often rev lower that four strokes. They just sound like it because they fire twice as often as a four stroke.

[@warrenpuckett4203]

Yes then you could also get a 6 cylinder in it. At less than 6 cylinder weight and space. Twice as many power pulses per revolution. Heard lots of buzzin dozens and half dozens pulling the uphill grade in east Tennessee before I-75 was finished,,, miles away at night. Pretty much the same why a Atlas 6 was never in a pickup truck. TOO long. If you ever done under hood surgery on a T-Blazer/Envoy? Too much stuff under the hood and not enough space. I guess one of the advantages of cab forward. Or sompin like that? Don't want to say a disadvantage. That would not be nice. It would have been easy to get 400+ HP with a SMALL turbo on it. Might even need a tach. Just for looking at to see if the engine was still running. Yep that smooth and quiet. But if you turbo it and balance it for 9,000 RPM. That even fire thing sounds like a weed whacker. Instead of a angry beast. But wouldn't you just rather have V-8? Marketing Virginia. That is what sells cars. Women a the main buying factor in new car sales. A growing engine gets in the way of the phone conversations.

[@jeroenkoehorst4056]

But the design allows them to rev higher if needed. Lighter piston (no oil scrape rings) and lack of camshaft and valves.

[@jlo13800]

Yes 4 joke have to rev higher. A KX500 is a tugboat engine compared to todays 450 4 joke strokes which rev to 13K rpm's!

[@jlo13800]

yes exactly many bigger 2 stroke in sled barly hit 8k rpm but a 4 stroke crotch rocket revs past 13k rpm

[@73Datsun180B]

What fucking nonsense lmfao! A scavenge 2-stroke will always rev higher because of less drag because of no valvetrain and better gas flow and a uniflow 2-stroke will rev higher because of better gas flow. Can you explain why a shitty old 14L Cummins (350 big cam) is governed at 376hp @ 1760rpm with a turbo and a 14L Detroit (12v71n) is governed at 425hp @ 2150rpm without a turbo?

[@gwilliamwallace]

Great video thank you. Around the 7 minute mark you state that in a 4 stroke engine the camshaft rotates 360 degrees for every half a rotation of the crankshaft. It's the other way around.

[@jlo13800]

This is how a Hemi 2 stroke funny car works, nothing new here.

[@gregjohnson7270]

Thanks for sharing this information in away that non-engine techies can understand it. I think it's exciting news if we're going to continue to have gasoline engines while others - electric, hydrogen, water (?) are trying to expand their brands to become a viable replacement for the typical 4 stroke gasoline engines.

[@hardspaghetti9989]

the simplicity of a 2-stroke engine and the fact that you can rebuild a top end sub 1 hour is what makes them incredible, not sure how I feel about complicating the design further.

[@poguemahone5476]

The reason 2Ts need top end rebuilds is because the rings wear unevenly due to passing the lateral ports. This design could solve that problem along with total loss oil system which is the cause of high emission. It's not a new design but it might work better than the old diesel 2Ts. They are actually more fuel efficient and cleaner than 4T diesels, but only operating at around 100rpm, which is useless for light vehicles, but ideal for shipping, where they're still used extensively.

[@73Datsun180B]

@@poguemahone5476 71 and 92 series Detroit's run at 2150rpm from the factory, and the 53 series 3500rpm! They are called 4 -stroke eater for a reason!

[@richwood8650]

I love V6 and V8 two stroke sound. Evinrude handed me my first opportunity to hear a two stroke V8 in 1985. Very fast on the back of a boat.

[@jlo13800]

I got a 4L johnson, one of the best small blocks every made, 4 strokes suck!

[@janoskecsan1080]

Nice! You should have also mentioned mixture loss during scavenging at 2-stroke engine. Overheating issue can be significant. 4-stroke is good, because oil temperature on the cylinder wall does not exceed 120°C not to burn oil.

[@adeptustrashmechanicus2909]

"mixture loss" is handle, primarily, by variable valve timing. The ability to adjust duration on the fly is why EGR systems have become obsolete in gas engines in gas engines over the last 2 decades.

[@otomotiftrend]

Perhaps because it using DI, so gasoline injected after exhaust valves closed. The main concern, it would still need port fuel injected. To clean intake valves and manifold. DI has miserable long stories on carbon fouling in their intake valves and manifold.

[@marcoslima9631]

Direct injection solution

[@davidstuck2866]

I had that idea over 3 decades ago. but at that time no one was even remotely intersted in two stroke technology. I SERIOUSLY hope that Mazda, and then who knows who else will bring back the two stroke. can you tell that I am a two stroke enthusiast!?

[@kenandrieling5885]

Injecting gasoline directly into a combustion chamber at high pressure is a relatively new thing. We've been doing it with diesel for a long done but diesel is a lubricant

[@makoado6010]

google: two stroke diesel. welcome.

[@johnlehew8192]

You are absolutely correct. Two stroke was an automatic no if proposed. I was moving forward with a new engine design with a new thermodynamic cycle and many other advantages. Finally found an angel investor that knew about engines and had contacts that invested in ICE. He told me everyone who was interested, invested and lost everything they put in and were no longer interested in anything ICE. This was around 2009 and at that time all ICE angels were already EV angels. He said they already figured out way back then that EVs were the future

[@csjrogerson2377]

@@johnlehew8192 EVs were the future!! That didnt age well. I'm keeping my Mazda turbo diesel for as long as I possibly can. HGVs, trains and ships will be diesel for as long as crude is sucked up from the ground

[@barrybretz6073]

Will the octane number be of consideration in this high compression engine?

[@madeiramarescola]

Detrit diesel has been using this concept for decades! Boats and fire engines use them. Emissions were the only reason they weren't used in road legal vehicles since then.

[@rightwingsafetysquad9872]

A few mistakes in this video. In a 4-stroke, camshafts rotate half as fast as the crankshaft, not twice as fast. 14.7 AFR is the stoichiometric ratio for gasoline, but theyre usually run richer than that (smaller number). For diesel it is 14.5, but they are almost always run much more lean than that, between 18 and 30. Valve springs have no issue operating over 20k rpm. Valve float has been solved. But the higher frequency you need, the more expensive they get. So the practical limit is around 14k rpm, not 8k. Doubling the intake frequency does not increase engine vibration in a way that matters to the user. Perhaps increased camshaft vibration is something the engineers would need to work out. Perhaps higher cost and weight, but not by a meaningful amount when amortized over the cost of a whole car. The supercharger is spinning the wrong way.

[@Anax100]

Also electric motors are not 50-60% efficient. Tesla Model 3 runs 88-96% efficiency island.

[@timeastman8319]

Thanks. Came here to point out the supercharger fuckup.

[@raymondo162]

........... and that is to mention but a few of the many errors along with total bs

[@rebekahfrench5747]

Both 2 stroke blown motor animations are running in reverse 😂😂😂

[@joecummings1260]

Yeah you have to wonder about a vid made by someone who doesn't understand a roots blower

[@goatman86]

For a moment I even thought they used supercharger to help evacuate exhaust gases faster 😂

[@josephpadula2283]

I did not notice till you pointed it out, thanks .

[@creepingjesus5106]

Well, that just sucks. I'll get my coat...😂

[@baby-sharkgto4902]

They also state that in a 4-cycle engine that “the camshaft rotates 360* in half a crankshaft rotation”

[@timothybontrager3510]

The start of an exhaust sound in any internal combustion engine starts at the exhaust valve or port. The quick opening square edge exhaust port, in a two stroke, gives them their distinct sound venue, add the expansion chamber with its reverse cone and stinger which add to the high RPM Shriek. A poppet valve, Otis cycle or Miller cycle engine has a slower opening round exhaust area that is shrouded by the center valve. These motors there, pop, pop, pop, noise. Just a few small things that influence exhaust noise.

[@tenmillionvolts]

And what makes Hondas sound like a screaching fart? 😀

[@NLynchOEcake]

I suspect the same thing, it's going to have a bit of the 2 stroke brap, it's gonna have a bit of the diesel chug, it's gonna have a bit of the 4 stroke cam noise. I think it'll sound probably like a more sharp and loud, less throaty and resonant version of a straight-piped 4 stroke like a Harley, quick hard pops in rapid succession but overall a low tone due to the low RPM

[@glennlane6599]

At the 7:20 mark you state that in a 4 stroke engine the camshaft rotates 360 degrees in half a crankshaft rotation. That's backwards, that would have the camshaft running twice the crankshaft speed and in fact the camshaft rotates at half the crankshaft speed.

[@SJR_Media_Group]

I designed a 2 stroke gas engine years ago. We use the 360 degrees of crank rotation differently and avoid contamination of un-scavenged exhaust left in cylinder. We used a belt driven compressor setup to suck, not blow. The negative pressure in exhaust manifold pulled out exhaust gasses very quickly. We used a compound forced induction with twin turbos feed into the supercharger. Also, we used short stroke and 6,000 RPM was achievable. On paper that is same as 4 stroke running 12,000 RPM. But 2 stroke is slightly less efficient than 4 stroke due to less time for almost overlapping intake and exhaust cycles. Un-scavenged exhaust led to over heating and less combustion flame propagation. In it's final configuration, we ended up with a radical 12 cylinder flat engine (similar to 2 flat six cylinder engines for perfect primary and secondary balance) with 2 crankshafts on end and opposing pistons sharing 1 common head / combustion chamber in middle, with variable chamber volume. We could increase combustion chamber 1X - 5X.This allowed for high CR (1X) under low / no boost, then low CR (5X) under high boost. We were making 2,500 HP - 5,000 HP. The magic is in the special head and crankshaft. Heads have 4 valves for intake and 4 valves for exhaust. Intake ports are on top of head and exhaust on bottom perpendicular to piston. Crankshafts can more up and down to increase or decrease compression ratios.

[@gbone7581]

You cant create negative pressure, once it gets to zero that is it! It is the higher pressure in the cylinder that pushes the gasses into the exhaust.

[@SJR_Media_Group]

@@gbone7581 Thanks for comment... a vacuum is negative pressure as is high altitude.... in WWII, high altitude bombers used supercharging to make up for less oxygen in low pressure. Even forcing more air in didn't solve a problem with engines still running very lean. It was discovered that at high altitude, exhaust gasses encountered much less back pressure, and cylinders could pull in more air, leaning out the air fuel mix. Air Pressure at different altitudes: Sea Level 14.7 PSI 10,000 feet 10.2 PSI 20,000 feet 6.4 PSI 30,000 feet 4.3 PSI The higher you go, the less air pressure there is. Our vacuum savaging reduces air pressure so there is less back pressure. This allows for complete removal of all exhaust gasses that plagues most 2 stroke engines. Not only that, since air pressure is low inside cylinders on intake stroke, it is easier to put more air, and forced air induction becomes more efficient.

[@bikefarmtaiwan1800]

It a great idea ! I'm interested to see how many people had a similar idea to the Mazda development ( including me :/) I guess that is what comes of being a two stroke enthusiast! Your development is also very interesting .

[@SJR_Media_Group]

@@bikefarmtaiwan1800 Thanks fro comment

[@raymondo162]

@@gbone7581 "You cant create negative pressure..........." you can - negative pressure is called 'vacuum' and you create vacuum using a vacuum pump.

[@lindafoxwood78]

Nice video. I was drawing up some ideas about a 2 stroke engine 30+ years ago, but never made a working proto-type. My idea was exactly like this motor! I used the supercharger to force the air into the cylinder otherwise it could run backward and stall. My idea was to convert existing 4 stroke engines into this type of 2 stroke. My idea still might work like i thought; but I am glad someone can make the engine I designed on paper.

[@bikefarmtaiwan1800]

Those were the days when we could dare to design . Like you I had an idea rack design 30 years back - the EPA have fucked that up now :/ . They can discount colbalt mining and solar farm renewal pollution to push their EV agenda . Great to know there are free-lance designers like you about :)

[@kurtcpi5670]

This sounds really practical. What's lost in horsepower due to lower RPMs should be easily made up in the torque produced with power on every stroke. That should be very noticeable at low RPMs. One of the features of electric motors is the immediate torque when you step on the accelerator pedal. Having a 15:1 compression ratio that can be maintained at low RPMs should deliver that same kind of oomph.

[@robertomalatesta6604]

What with do you fuel a 15: CR?

[@kurtcpi5670]

@@robertomalatesta6604 You use gasoline. The engine is fuel injected. The only thing being compressed is air, so there's nothing to ignite spontaneously. At the point where the sparkplug would fire in a traditional 4-stroke engine, fuel is injected. The reason you can't have a 15:1 compression ratio with 85 octane gas in a conventional 4-stroke is that the mixture ignites from the compression long before the piston reaches top dead center. As long as there's no fuel to burn prior to the proper combustion time, it's not a problem. They didn't go into the specifics, but they mentioned variable cam timing, suggesting that at lower RPMs the valve timing would be later than at higher RPMs when there's more spark advance. Also, with that much compression combined with residual heat from EGR you could run a pretty lean mixture and still get plenty of torque for low-demand situations. When you "step on it", the EFI can provide a richer mixture to meet the demand.

[@timyanke9559]

yes and operating at 4000 rpm with 2x the power strokes would be comparable to 8000 rpm in a 4 stroke engine

[@Antopc2]

or if you are limited by the speed of 1 injector for 4000 rpms... you can add a second one for 7200 rpms. just like how dodge hemi and some motorcycles / air planes have space to fit 2 spark plugs per cylinder....

[@lunatik9696]

great video with excellent animations. Electric motors are 90% efficient. Overall system efficiency including battery charge/ discharge and control electronics is 80%. Achieving 50% thermal efficiency in ICE is tremendous. Standard passenger cars are in the 20% range to keep emissions in check. These new 2 stroke engines would best be for a charging system in a hybrid BEV. By adding additional cylinders (total of 3) would theoretically balance out the vibration along with some fine balance tuning.

[@TheElandorr]

Odd number of cylinders will always be odd to me! 2, 4 or 6 in my opinion are best configurations for number of cylinders at least... But of course there is a room for discussion always !

[@malibudan]

What is the efficacy of the electric power station delivering the energy?

[@WJV9]

@@malibudan - If it's wind or solar then very high, coal or gas not as much likely 40 to 50%. A typical gasoline engine is 25 to 30% max. Permanent magnet electric motors will make 98% efficiency. Induction motors are 90% or more efficient.

[@halvaraspegren7635]

​@@WJV9 and now theres diesel engines with 50%efficiency, maybe we shouldnt count the ICE out just yet...

[@TheNitrox88]

​@@halvaraspegren7635diesel car engines archive 35-40% max in a good operating window.

[@Xlaxsauce]

I'd like to see their CFD around their valves and in the cylinders. I would think the cylinders would foul much quicker than current solutions. It would be complicated but it'd almost make more sense to have the intake and exhaust valves be concentric rings with the intake being near the cylinder wall and exhaust being somewhat central. Make them flextures to maintain strength.

[@vinibali]

There is also a small amount of power loss, while the exhaust ports are opening before the detonation can fully push down the piston. Of course this and the overlap between the valve openings are needed for this concept to work. I'm really looking forward to see this in action!

[@thekaxmax]

that and the 70+% energy loss from using the Carnot cycle.

[@bodegabonsai7069]

Long before the internet, I designed a rotary engine. I drove from New York to the patent office in Washington D.C. to see if my design was patentable. I was shocked at how many engines are patented that never found their way under the hood of a car. The fact that this engine is patented means nothing. Many 2-stroke engines use superchargers and valves. An intake port on the side of the cylinder and an exhaust valve up top make the most sense to me. Keep the incoming charge and the outgoing away from each other. Mazda stuck them right next to each other.

[@williamvandongen]

Did you find this patent? 2-stroke engine with an intake port on the side and an exhaust valve on the head?

[@victorsteerup4582]

This idea was proposed a long time ago. An article showed a conventional DOHC engine with different camshaft gearing 1:1. Complained that at 4,000 rpm the valves were operating at the frequency of 8,000, if it were a 4-storke. I immediately thought that if the cam lobes on each cyl were offset 180 degrees, and only 2 valves opened on each stroke, that would solve the problem. Now the flow would be halved, but there is a blower to scavenge.

[@marcox43]

that is indeed interesting, alternating valves to mimic a 4-stroke valve limit. Valve stuff kinda applies to NA engines, but since this is forced induction, no problem if 2 or 4 valve. that engine will surely need a beefy cooling system to cope with actual 8000rpm... sound must be insane too. would it be possible to use a centrifugal supercharger instead? like aero engines where it was directly coupled to the engine via sprockets.

[@bikefarmtaiwan1800]

You seem to be the only other person that has mentioned 1:1 gearing from the crank to the camshaft . This has to be the case if you only have one love on the cam per valve . I'm amazed no one else seems to have picked up on this .

[@user-oz5yk9bm5c]

10:53 : "given that springs ideally work in revolutions below 8000" Honda: *Nervous laughter*

[@z987k]

Ya that comment only has basis in reality if this guy is talking to us from 1985. Spring tech has come a long ways. If a company can't produce valves that don't float past 20k rpm, they need to not be making spring for anyone.

[@warrenpuckett4203]

Then there is the use of double and triple springs. Each spring has a different interference harmonic. But then Honda was never a K.I.S.S. engineering advocate.

[@steved4429]

Another solution could be forced closing actuators al la Ducati. I used to love my old 70s Jap 2 strokes, but don't see Mazda developing this, as the world is being forced to go EV?

[@jeroenkoehorst4056]

@@z987k 4-stroke motorcycles from '85 had no issue running above 8000rpm. This whole video is a mess.

[@fidelcatsro6948]

Ducati: We solved that with Desmodronic system!

[@LordCakeskull]

Having intake valves too is pretty novel. I worked on 2 stroke diesels for a long time which had supercharger and turbo, with exhaust valves. But intake too, and with petrol? Very intrigued.

[@CAPTIVEPULSEMAKER]

kzbin.info/www/bejne/iYqohoaiZ9uioqc

[@tsclly2377]

Good for a constant speed engine - electric generator setup were efficiency is efficiency and lower output is required. the vhicle still would be electric powered and acceleration achieved by battery - capacitor power.

[@RayBaker-u6w]

I’m kinda surprised it’s actually quite clever. And it looks pretty much worked out

[@creepingjesus5106]

With DI and integrated EGR, it'll be interesting to see how long the valves and seats last before they need decoking. We already see that in contemporary four strokes, and those of us who know about old two strokes know how bad they were for fouling plugs, never mind coking up everything around the combustion chamber. I kinda hope Mazda can pull it off: for one, an unconventional Mazda engine that *doesn't* burn oil; and for another, many companies (Lotus and Ricardo Engineering spring to mind) have failed to get it right. It was assumed then (in the 1990s) that better injection control would be the answer. Maybe this is it...?

[@samsonian]

Maybe they’ll have to do it like Toyota (run 2 fuel systems) and have a different operating mode for when fuel is introduced pre-chamber…dunno. I’m not an engineer.

[@adeptustrashmechanicus2909]

Without oil in the fuel, coking will be about equal with the current generation of DI engines. - And that is just on the intake valves due to crankcase contaminants being cycles back into the intake by PCV.

[@mikeb3172]

Can technically point the injector at the spark plug to keep it clean

[@machintelligence]

@@mikeb3172 Although the animation shows a spark plug, the engine is actually a diesel engine. Carbon fouling of the valves could still be a problem.

[@kennethwers]

@@machintelligence Sounds like the spark plug would only be used for startup.

[@Bullwinkle056]

A company called Orbital from Australia spent over a decade trying to make direct-injection 2-stroke engines work in outboards and cars. The final nail in the coffin was that they couldn't meet the emission standards after 100K miles.

[@kennethwers]

Was Orbital using cylinder ports?

[@matthewmckenzie7687]

But their injection tech lives on. In fact, like a rotary the core was not complex and could have easily been swapped out at 160,000km, but that's 2 years of driving in Western Australia.

[@Bullwinkle056]

@@kennethwers Yes

[@johnlehew8192]

There is an oil mist from the crankcase, if that goes into the cylinder thru ports it would hurt emissions. Without seeing their design, I suspect that was the issue. This design won’t have that problem

[@Minuz1]

If it won't meet the emission standards I guess they'll just put it in a truck and market in the USA.

[@GiGaSzS]

Sounds promising, but we will see if there will be any issues with the engine and if there will be enough momentum to push another ICE revolution. I am all for keeping alive the spirit of ICE and pure mechanical/analog feel of the cars.

[@Sloppyjoe96]

alot of people are more likely to buy this than a EV, if its any good atleast

[@MadScientist267]

It's not even a new idea 🤦‍♂️

[@Sloppyjoe96]

@@MadScientist267 i mean wasnt 2-stroke the first gasoline engines developed right? lol

[@dougdouglas2112]

Mazda is a rebel car company...rotary engines, 2 stroke supercharged engines. Refreshing to see a major corporation that walks their own line.

[@josdaalmans6977]

It's Mazda and every other car maker is eager to find out how new enginws are going to look like. We drove 2 time MX 5 and now for years a CX 5, industrutable and good quality. We'll see this in the future👍

[@PaulG.x]

The pump in a two stroke diesel is not a supercharger , it is a scavenge pump . It operates at ambient or close to ambient pressure . No supercharging occurs. If supercharging is desired , then turbo-superchargers running off exhaust gases will be added to the engine

[@tetttettamilli6761]

@FT - Leave it to Mazda to ride the cutting edges. This is incredible technology. And this would seem to require technicians learn an entire new regime. K, redit - I had to return - (1) Is that a fuel return line? It looks like there's a heat exchanger to keep gas tank temps low(?) (2) With no port injection (and burning diesel?) it's going to be susceptible to carbon buildup on the valves, which would be critical as valve seat design is integral to the flow of intake and exhaust with both valves open. And low RPM, but heavy? Well, trucks and ships would be a good fit, no? As I said, it's interesting technology, and life is about learning; bring it on.

[@stevelee5724]

Hi Allan. The Z900 is a Beauty mate. Well done. Cheers from New Zealand 🇳🇿

[@sankyppp]

With my limited understanding of engines, I feel that adding valves doesnt give too many gains in volumetric efficiency as the same can be achieved with forced induction on conventional port type arrangement. It probably helps in not letting lube oil get into the exhaust valve. Am I correct?

[@sshardchrome]

Im my opinion, this needs compressed air at start in some container or maybe electric turbo to get boost rightaway in low revs.

[@matthewq4b]

Nope the super charger will provide enough air just like it has with every Diesel 2 stroke in history.

[@samuelhayes5198]

I dont get how they could get a patent on this? Its all stuff thats been thought/designed/used before?

[@TheCraigy83]

the patents expire , large companies are sat waiting .

[@Jodyrides]

in the late 1980s, every car manufacturer from fiancé, general motors, Ford, all the way down to Daihatsu had running prototype two stroke cars ready to go into production.. The Toyota design had a wet, crank case, you checked the oil with a dipstick, just like a four stroke. The advantage was, all of the metal needed to create an engine, the weight of which produced twice the horsepower of a four stroke engine of the same weight.. or The two-stroke engine would produce the same amount of horsepower as the four stroke engine with an Engine weighing, only half as much as the four stroke.. All the car companies were just about ready to give this 2 stroke plan the go ahead. All it needed was government approval from the environmental protection agency, EPA.. but The results of long-term testing shot that down. Because….. not one of the companies prototype engines could pass the EPA air quality tests after the engines had the equivalent of 100,000 miles of driving on them.. SAAB had two stroke cars running around in the 60s, there have even been large, two-stroke, dump trucks, trucks for pulling tractor trailers that were two stroke. But the air quality issues/requirements of the future ended the two stroke car before it even got started by all of the car manufacturers in the late 1980s.. I have been a motorcycle mechanic and a motorcycle enthusiast since the 1960s. I am currently on my 107th and 108th motorcycle so far. I roadraced motorcycles, winning six championships, two time national champion, I rode off road, two stroke dirtbike‘s for more than 30 years, motocross, bikes, trials, bikes, I rode two stroke, singles, twins, and triples on the street… I have always done all my own maintenance even on my road racing machines. And there is one thing I do notice about two strokes. they don’t last very long. My road racing machine, factory recommendations, new pistons, every 600 miles, rebuilt, crankshaft or new crankshaft every 1200 miles… The engine trouble I’ve had racing or dirtbike, riding or trials, bike riding, or even street bike riding, have pretty much all been the two strokes, piston seizures, that was the biggest fastest wearing parts, the pistons, rings, cylinders.. on street bikes, like my Yamaha RD 350s, 250s, Kawasaki S2 350 2strokes.. my dirt bikes, KDX 175s and 200s with hard plating in the cylinders, pistons were the weak part. And that is due to marginal lubrication of two strokes. They lubricate the engines with already diluted oil, that has been diluted by gasoline, which is a solvent… A film of oil is only so thick, and a diluted film of oil is only marginally sheer resistant.. there is a lot of engineering and tuning and tweaking of fuel injection systems that will have to be sorted to make any two-stroke engine. Be both EPA responsible, and, be reliable at the same time… no engine suffers more from altitude change than a two stroke. They lose 15% of their power just going from sea level up to a city as high as Denver, which is a mile above sea level.. Super chargers and turbo chargers can reduce that power loss somewhat, with a lot of extra systems to compensate.. cooling the engine will be an ordeal itself. Not to mention how do you cool the piston. They are prone to burning holes in 2 stroke pistons because they fire on every stroke. They don’t get that intake stroke to cool down that a four stroke gets… three of my biggest injuries at roadrace tracks have been from two-stroke engine seizures. My last one was my last race, I woke up two days later in plaster in the hospital after that 140 mph seizure on a Yamaha TZ 250 Factory Rd. race machine… of course, that happened during the days when you had to jet your motorcycle according to elevation, barometric pressure, even taken care to consideration the humidity and temperature into your carburetor jetting. I got it wrong that day… but my point is, in my experience, the Pistons of two-stroke engines are the weakest link. I wonder if Mazda can make a two-stroke engine that the piston will still be within spec and pass an EPA sniffer test at the 100,000 mile mark.. I hope they can do it. They are the company that seems to be the ones that are willing to roll the dice, look at the rotary engine that Mazda has been producing. It didn’t pan out when that was first introduced. A friend of mine bought a 1973 Mazda Cosmo rotary engine car right after he got out of the Navy. In 1973 that car was over $7000. he never had a problem with it. Of course he only kept it for about three years… but willingness to take chances the way Mazda does is a risk. Look how long it took mazda to improve the rotary engine seal problem… I really hope that Mazda has some type of a breakthrough with this two-stroke development. Because I have no plans to ever go to an electric vehicle until I absolutely have to. i’ve worked in the electrical generation field for the past 38 years until I retired. And occasionally the subject came up about California’s electric grid, problems, brown outs, rolling, blackouts, and their inability to make a decision about building new power stations. It takes 12 years from idea to going online when it comes to building a power station. and then California would like everyone to drive an EV.. but consider this. If every car in California right now, what is an electric vehicle.. every bit of electrical generation capacity they have whether it is from wind, solar, Hydro, natural gas, coal, nuclear, All of those generation abilities, concentrated on just charging the batteries of EV cars, is not enough, there’s no possible way that California’s electric grid dedicating every volt of generation capacity Simply to charge car batteries could ever meet the demand if every car right now was an EV.. I would like to see more development of the hydrogen engine. I don’t know if the big oil companies and their lobbyists are keeping the government from putting them out of business by going to hydrogen tomorrow, but it seems like that is a more practical solution than electric vehicles. good luck mazda..

[@bikefarmtaiwan1800]

Interesting input - thanks for sharing your experience .

[@paradiselost9946]

the first car ever powered by an ICE was a two stroke. etionne lenoir, circa 1860.

[@justlooking6898]

Great video - I've wondered how this could be done, for a long time. Diesel/4-stroke/2-stroke. Great! 🤩

[@brucerusk7934]

You won’t be hearing it as it will be mated to a generator. It will sound similar to any other cvt car. Rev up to whichever rpm meets the load criteria and probably only at speed.

[@leszekpaterek2389]

Fajne symulacje. Szkoda tylko, że wirniki sprężarek obracają się w przeciwną stronę niż w rzeczywistości :(

[@timfeeley714-25]

The engine actually works in the reverse of what is described!😂

[@grantensrud9185]

Now, how would Mazda get a patent for what Detroit Diesel did 80 years ago? Only difference an intake val

[@grantensrud9185]

@retiredbore378 I have wondered for a long time what a 2 cycle diesel boxer motor would sound like... I love the old Detroit diesel. Just think a 2 cycle boxer with opposing cylinders firing at the same time every time...

[@jlo13800]

@@grantensrud9185 mart.cummins.com/imagelibrary/data/assetfiles/0058689.pdf

[@SteveJohnson-wb3fl]

Overheating will probably need to be overcome. Also, twice the power (2 stroke) with half the cylinder rotation is countered by the belt driven air compressor. There is no need to fear EVs taking over. The drawbacks are explosive. 🔥

[@howardsimpson489]

The main current problem with EVs would appear to be explosive lithium chemistry. Most owners would trade high power/speed for reliability, quality and affordability.

[@edwardmylnychuk5774]

anyone using a tesla has done no research on that crap

[@martinnewbery3032]

Wow !! That's the most interesting engine video I've seen. What a very elongated process the 4 stroke engine as we know it, is. Best of luck with its development. Look forward to hearing more about it in the future.

[@NBC_NCO]

Very nice to see old technology revived for a modern world.

[@neilwalker8686]

Your supercharger is running backwards.

[@iangardiner8535]

Got it in one. You'd think they would be more careful.🙃

[@atiutube2887]

you beat me to it!

[@ShaneEstabrooks]

A small engine like this in a EV to extend it's range sounds good.

[@MichaelWashingtonAE]

Unnecessary to do that.

[@geofforick7870]

Unlike a regular 2 stroke, you can direct inject gas after the exhaust is closed. The problem in 2 stroke is that some fresh gas escapes out the exhaust before the exhaust port is closed by the piston. Also, your animation has the supercharger running when the crank stops and should actually stop when the crank does. I think this could possibly be converted to existing engines with a cam swap and new programming for injectors and adding a supercharger and high pressure fuel system. This video also got me thinking why there is no 2 stroke diesel hybrid system or regular diesel hybrid system. Mazda has always thought outside the box and especially with the Wankle rotary motors. I'm a Toyota guy, but Mazda is to be commended for pushing technology. If you always do what you've always done, you'll always get what you've always gotten.

[@jlo13800]

It acts as an exhaust trapping valve

[@Charlerdfgh]

So mazda patented something thats been around for a long time, i have seen a camless engine capable of seamlessly switching between 4 stroke and 2 stroke mode of operation making the best of both worlds, something that should be easy to make today with koenigsegg freevalve system.

[@SuperKaterman]

I love that Mazda is still putting R&D to work! Another example is the "Wankel" (rotary) engine in the MX30. Unlike other manufacturers Mazda does not focus on the fully electrical movement.

[@marcioferraz5282]

In regard to the fact that the revs would drop to 4.000rpm I guess the resulting sound would not be that high pitch pleasing sound we're used to hear but - provided it would keep the same exhaust and adjacent pipes and etc - it might keep the same tone, just at a lower level. *I raced a lot in kart competitions using 125 cc 2 stroke motors and the sound were gorgeous. People get thrilled with that sound! 😎

[@markholmes5695]

I like the AI south Dublin accent 👍 greetings from Ireland 🇮🇪

[@BoomerNuke-el4fj]

I wonder if non poppet rotary valves were incorporated if further improvements could be made as well? Also use of that new piston design which incorporates a continuous oil seal ring to minimize "seep thru" too?

[@HDJess]

It doesn't surprise me at all. I've had this idea more than 10 years ago and I've always wondered "why don't they make engines like that?". But then I've always known, if I get an apparently brilliant idea, it's certain many other have had it way before me.

[@massmanute]

On the topic of sound: Years ago I worked with a Roots blower in another application. The noise of the Roots blower was an almost deafening whine. You mentioned noise, but I don't think you discussed the issue of noise from the roots blower itself. Can you comment?

[@barneyklingenberg4078]

Very well made explanations and graphics. 1 thing though. 2 stroke exhaust systems have far greater effects on efficiency and power then with 4 stroke engines. But they only work well in a narrow rpm range.

[@johnsherwin1104]

Off setting the crankshaft to the compression side of the cylinder is a common way to almost completely remove oval wear pattern on the piston and cylinder. Additionally important to high compression motors.

[@Z_PixelHUN]

the sound will be vroom vroom

[@masakikusahara5365]

Oh Mazda you reinvented the wheels again. Mad respect.

[@StefanGoudreau]

I love Mazda's ingenuity and passion for thinking outside the box

[@philldownes8685]

mazda dont think outside the box. the yalways go back to old designs look at the problem and try t osolve it then say its theri idea.. remember the rotary engine they claimed to have invented ?

[@daciolaires6445]

@@philldownes8685 Mazda never claimed they invented it. They bought the patent from Wankel and and improved on it. Do some research on it.

[@guest6423]

A.I. is so pleasant to listen to.

[@atsekjoker]

cool, BUT ... why not just a side exhaust port like 2stroke motorbike engine?

[@Craig52-zq1bt]

2 stroke, a power stroke for EACH piston stroke. Would make a great motorcycle engine.

[@jlo13800]

makes a nice truck engine too.

[@baconshark8067]

Once per revolution per minute... Makes so much sense! If we do some kindergarten level mathmatics, this would be a 1 RPM motor.

[@JimBerkeley-o9v]

I believe that Toyota took a very similar approach several years ago using the 6 cylinder Supra motor. The rpm issue was there but I don't remember the other hurdles that they felt weren't worth the effort. However, the automotive companies are hooked on electronic fuel injection. The fuel delivery system can be simplified by substituting an fuel vaporizer using a simple FI system downstream from the compressor. Then the system would on pump a homogeneous gas mixture into the engine with a large range for AFR. This eliminates any chance of preignition. My experience on the dyno with a vaporizer system on a NA 4 stroke allowed up to 24:1 AFR without any misfire. This combination would really give this approach some legs and offer greater fuel economy and a simplified FI system with only 1 very large or multiple small injectors at low pressure. This would be similar to Yunick's mixing system but instead of using a turbo to mix and pressurize, the fuel vaporizer would do the mixing and the compressor pushes the mixture into the cylinder. There is very little data on using a homogeneous gas mixtures at elevated AFR's but there are real benefits if the research depts. would just explore the concept.

[@marlonmoss4235]

I have patented an engine very similar to yours . I was able to achieve the same results , but with out valves .There is one very inharent problem with thyour design , cooling . Under high torque situations the 2 stroke produces a lot of heat . My design incorporates air cooled pistons !

[@bahasha9861]

Traditional 2-strokes will have, at BDC a slight negative cylinder presssure that helps the rings to lift and lubricate. Mazda's engine will have it's rings fully seated and pressed into the grooves so that makes lubricating it and the walls a little more complex. Ditto for the wrist pins and crank bearings. And it'll probably sound like a four stroke engine.

[@Elmiki007]

I don't know but the sound and insane ingeniring of the Mazda 787b shattered my mind

[@G4Nazarener]

Why do they use a inlet valve instead intake channels in the position of usual two stroke engines? It offers a better airflow with less friction caused by a valve.

[@musicauthority674]

It will be a low thumping sound due to the low RPMs. and it will require a higher gear ratio to make up for the engines low revs. I'm guessing this will be the first and last time. we will hear of thi new engine from Mazda.

[@timbrown9305]

So it will have at least one high pressure fuel pump? $1200 fuel pump if you're lucky?

[@Eikenhorst]

This is a clear improvement from the regular two stroke engines. A huge step forward! Except, two stroke engines are already not used anywhere pretty much. The question is: is this better than a 4 stroke engine, more specifically, is it better than a 4 stroke engine in motor vehicle use. I highly doubt it... The main issue is in the combined exhaust-intake-compression stroke. You are expelling exhaust gasses, partially by simply pushing them out with compressed air from the intake, meaning some of the fresh air gets pushed out of the exhaust as well and some exhaust gasses will not get pushed out at all. Then there is only a quarter of a stroke or so where only the intake is open, and compressed air is pumped in, this is inefficient because you are pushing in against the motion of the piston. Finally, you only have about half the upward stroke as actual compression with the intake valve closed. This is inefficient because you obviously can't compress as much as on a full stroke and with such a short opening time of the intake valve you also can't push nearly as much air into the cylinder. Everything is just done too short to be efficient, certainly compared to a 4 stroke. The weight savings are not enough to offset this, not on a car at least where weight is not such a big factor.

[@benjamincresswell3713]

I think it will sound similar, in a way, to a Detroit Diesel depending upon how high the RPM is allowed to go and how low they idle it. With the two stroke design, a 4 cylinder engine will sound like an 8 for any given RPM assuming the engine will have an even firing order. I ran Detroit 8-71's and 8-92's on electric dynamometers in a building so I really got a chance to hear them under controlled conditions. The sound was very different from any other Diesel due to the 2 cycle operation. During the testing I ran them up to rated speed, which was low at around 2,000 RPM but they sounded like they were going higher, although no where near as high as a V8 gasoline. I have also heard 8-71's and 92's in earthmovers and bull dozers as they carved out an expressway near my house. And lastly, I lived near a truck stop where at any given moment there were 50 trucks idling as the driver's slept inside them. As I drove along the line of parked idling trucks within just a few feet of the front of each it was very obvious which ones were Detroits. The Detroits sounded like they were running twice as fast as the 4 cycle Diesels. So, if the Mazda uses a 4 cylinder, with evenly spaced combustion/ power strokes I will say they will sound like a V-8 4 cycle engine with a higher top rpm sound but a normal idle sound. It will be interesting to hear how it sounds both at redline and at idle with computer controlled fuel injection. Depending upon the RPM Mazda chooses for the rated speed and idle speed, it should sound like it's revving twice as high at speed and about normal for a 4 cycle V-8 at idle, but not an ordinary 4 cycle 4 cylinder engine. One last thing: While I was testing Detroits on dynamometers they made the transition to DDEC and although it made no difference at operating speed, the idle sound became very very precise and may have been set reduced in RPM slightly. I can't remember what the idle speed was anymore as that was probably in the mid 1980's, some 37yrs ago. But I was there and remember the exacting difference DDEC made to the idle sound, it was as steady as a rock. ben/ michigan

[@mikecawthorn7806]

Who gives a sheet about making noise its a by product of power restiction removal. This is a great piece of work and my guess is its got a place to fill how long ice will be around is an evolution in progress.

[@BTP40]

Absolutely amazing video! Super cool! Unused exhaust reused without turbo genius

[@TheSkubna]

The catalyst system makes the burning of fuel more efficiently, but that's after ignition. It cleans the exhaust. What mostly aids power is the timing and fuel modifications along with all the electronic sensors contributing to efficient burning of fuel. Catalytic converter actually reduce the mechanical efficiency

[@robertorzech8922]

This is a beautiful engine also may be great for outboard engines for boats. Instead of the now 4 stroke ones ! I'm sure the blower can be incorporated into the casting

[@phroogo...]

Detroit Diesel has been using this tech since the company was formed

[@honeybadgeractual5734]

Ive been saying for YEARS, we need a pressurized intake 2 stroke that uses a port timing on the intake and a set of exhaust valves that release pressure at timed intervals for maximized fuel efficiency. Less losses of unburned, more power, better cooling. You could hybrid cool the head using air and water jackets.

[@TrevorSachko]

Awesome! They invented something already invented.

[@stumpbumpers]

I like how Mazda takes everyone else’s technology and puts it together and calls it their own.

[@Shan_D]

Regarding RPM problems, if we use something that is basically fully connected at the cam shaft (so basically forgetting about springs) wouldn't that fix the problem? I'm not an engineer maybe lubrication, vibration or something else can cause problems but still

[@Daniel-du4um]

The only thing I dont fully understand is the compression ratio 15:1. Will it run on ethanol/methanol blend? Or some high octane fuel? Or is it just a geometrical compression ratio, and the air fuel mixture is compressed slightly less due to the fact, that the exhaust valve is being opened for a short time while the piston goes up?

[@hillbilly4christ638]

Like any engine, heat mitigation is key. It is used here to benefit the process. I hope they move to an in-line configuration. This has some promise. Lighter weight perhaps.

[@crazychop6162]

The sound would still be similar to an engine of the same orientation and number of cylinders that is running at twice the rpm. So if it runs at 4k rpm it could still sound like an engine at 8k rpm if it has the same exhaust system

[@RicardoMoreiraKrahnin]

It looks very cool on paper, because people only think in CO2 emissions which are no toxic, but I belive that engine will produce more NO and NO2 which are not as friendly