ALREADY PATENTED!!! - 2 Stroke Engine with Advanced Valve System From Mazda
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- čas přidán 4. 01. 2024
- ALREADY PATENTED!!! - 2 Stroke Engine with Advanced Valve System From Mazda 300051
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#TURBOCHARGER #SUPERCHARGER - Věda a technologie
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.
when in school 16 years old i designd this but at school they said its like a two stroke diesel
All New this is good forgeten old
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!
@@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.
The mazda 2stroke will sound like a four stroke engine with a fast pulse.
Love how Mazda is involved in so many diverse technologies and are trying to reinvent the 2 stroke!
Mazda and Toyota are some of the only companies actually moving forward with innovation rather than just inventing stuff and sitting on it.
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
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
@@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.
Except this is 100 year old technology, lol
It's amazing that Mazda created a backwards spinning supercharger!
It's called the reverse flow engine, amazing huh!😂
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
And that air intake is on the same side for both parts of the supercharger
@@josephrheaume8386This design actually pulls air from the exhaust and blows it out the air intake. It's revolutionary.
@jonrice21 the pressure at the valve from the super charger just has to higher than the cylinder when the valve opens.
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.
They are getting closure to diesels including the need to having a particulate filter (mandates coming soon to the EU)
I like that Mazda is willing to walk a different path to other companies.
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…
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.
@@MrPaige222 all you do is complain
If your definition of complaining is observing and speaking the truth...
Then in your mind I guess you have a point.
@@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.
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.
I noticed that had had a little chuckle
the Supercharger is also rotating backwards.
Hard to take this seriously when they get basics wrong
he 100% said the same thing. A 2 -1 ratio.
@@emknapss Or is the animation reversed?
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!?
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
google: two stroke diesel. welcome.
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
@@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
Will the octane number be of consideration in this high compression engine?
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.
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.
I loved selling Cummins against them!
Actually the 12V series made a bunch of power. Especially in boats, when they added twin turbo chargers to the mix.
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.
A dude on the tube just made a common rail Detroit powered drag truck, makes some real power
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!
Truly amazing how well these new engines work in CAD.
Its different. The engine that you mean, its has hole on liner.
So true.
This one is working with the blower rotors spinning in the wrong direction.
This has got to be one of the worst explanations of engine operation I've ever seen
😂😂😂 Nobody else caught what you were trying to say ..
I get the point of your comment loud and clear and YES, I agree ..
@@davehart7943 We got it fine 🙄
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.
What with do you fuel a 15: CR?
@@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.
yes and operating at 4000 rpm with 2x the power strokes would be comparable to 8000 rpm in a 4 stroke engine
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....
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.
Was Orbital using cylinder ports?
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.
@@kennethwers Yes
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
If it won't meet the emission standards I guess they'll just put it in a truck and market in the USA.
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
👍👍
GM had poppet valves on their 2 stroke diesels and a supercharger. Powerful and reliable engines.
@@carlosbonifacio825and very noisy!
@@americanrambler4972 But also awesome :)
czcams.com/video/kRziS6C3i1Q/video.html
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.
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.
Yeah, no you didn't. Lol. Stop lying
And you didn't modify the ignition?
@@dubsydubs5234 If it's wasted spark ignition, I believe you don't need to.
@@SmeurkeDeKat True.
You made it into a 2 stroke!
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.
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.
Somewhat simple, yet totally brilliant design. I love engineers that come up with great stuff like this, and love the companies that support them.
czcams.com/video/SYEUSl2volE/video.html
czcams.com/video/SYEUSl2volE/video.html
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.
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.
But the design allows them to rev higher if needed. Lighter piston (no oil scrape rings) and lack of camshaft and valves.
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!
yes exactly many bigger 2 stroke in sled barly hit 8k rpm but a 4 stroke crotch rocket revs past 13k rpm
Both 2 stroke blown motor animations are running in reverse 😂😂😂
Yeah you have to wonder about a vid made by someone who doesn't understand a roots blower
For a moment I even thought they used supercharger to help evacuate exhaust gases faster 😂
I did not notice till you pointed it out, thanks .
Well, that just sucks.
I'll get my coat...😂
They also state that in a 4-cycle engine that “the camshaft rotates 360* in half a crankshaft rotation”
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.
This is how a Hemi 2 stroke funny car works, nothing new here.
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.
10:53 : "given that springs ideally work in revolutions below 8000"
Honda: *Nervous laughter*
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.
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.
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?
@@z987k 4-stroke motorcycles from '85 had no issue running above 8000rpm. This whole video is a mess.
Ducati: We solved that with Desmodronic system!
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.
I got a 4L johnson, one of the best small blocks every made, 4 strokes suck!
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.
I came up with this idea in 1976 as a teenager and drew it on a piece of notebook paper. I eventually sent a copy of this idea to a company for evaluation.
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.
"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.
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.
Direct injection solution
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.
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.
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.
Superb video! The graphics have really helped me understand these types of engines a lot better, great commentary too.
I have aphantasia (no mental imagery) so the clear graphics were immensely useful.
New sub here!
wow Aphantasia i learnt a new word!
@@fidelcatsro6948 happy to help!
Only learned it a few weeks ago myself!
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.
And what makes Hondas sound like a screaching fart? 😀
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
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.
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 !
What is the efficacy of the electric power station delivering the energy?
@@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.
@@WJV9 and now theres diesel engines with 50%efficiency, maybe we shouldnt count the ICE out just yet...
@@halvaraspegren7635diesel car engines archive 35-40% max in a good operating window.
Just found this channel. Excellent graphics and explanation!
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
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.
czcams.com/video/SYEUSl2volE/video.html
Nice animation, but you have the blower turning in the opposite direction. Air moves around the outside of the lobes, not thru the middle. The Detroit diesel mentioned below was considered naturally aspirated because the exhaust valves opening overlapped with the intake ports briefly for air flow thru the cylinder. They had to have blowers to start, but once running, turbos would relieve the power draw of the blower (about 25% of engine horse power) giving the engine more power and better fuel economy.
Remember reading about this concept in a Hotrod magazine in the 70s sometime being researched in Australia by Ford I believe. Always assumed that is how they came up with direct injection used on ecoboost motors.
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.
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...?
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.
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.
Can technically point the injector at the spark plug to keep it clean
@@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.
@@machintelligence Sounds like the spark plug would only be used for startup.
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!
that and the 70+% energy loss from using the Carnot cycle.
I'm excited to hear a stroker 2T gasoline engine large enough to power an automobile. Even as an I4 engine, it would sound more like a high-revving, flat-plane I8. I also wish that Freevalve would have received more interest and refinement from major brands, which would have pair perfectly with a product like this. One that could benefit from complex valve timing algorithms.
Your supercharger is running backwards.
Got it in one. You'd think they would be more careful.🙃
you beat me to it!
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.
alot of people are more likely to buy this than a EV, if its any good atleast
It's not even a new idea 🤦♂️
@@MadScientist267 i mean wasnt 2-stroke the first gasoline engines developed right? lol
Hi Allan. The Z900 is a Beauty mate. Well done. Cheers from New Zealand 🇳🇿
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.
Now, how would Mazda get a patent for what Detroit Diesel did 80 years ago? Only difference an intake val
@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...
@@grantensrud9185 mart.cummins.com/imagelibrary/data/assetfiles/0058689.pdf
@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.
the sound will be like a banshee's screech.
great vid.
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.
Sound wise, with more pulses per rpm, I would expect a more rotary/smoother sound. Additionally the sound may be deeper than similarly sized conventional engines
Im my opinion, this needs compressed air at start in some container or maybe electric turbo to get boost rightaway in low revs.
Nope the super charger will provide enough air just like it has with every Diesel 2 stroke in history.
Oh Mazda you reinvented the wheels again. Mad respect.
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?
Fajne symulacje. Szkoda tylko, że wirniki sprężarek obracają się w przeciwną stronę niż w rzeczywistości :(
The engine actually works in the reverse of what is described!😂
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..
I used to be a guy who could get it done with 3 strokes, yet I'm happy someone can do it with just 2
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.
I dont get how they could get a patent on this? Its all stuff thats been thought/designed/used before?
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. 🔥
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.
anyone using a tesla has done no research on that crap
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.
Great video - I've wondered how this could be done, for a long time. Diesel/4-stroke/2-stroke. Great! 🤩
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
Neat idea. Great for economy.. but I like to work on my stuff. Complexity is a deal breaker.
I do like the concept of keeping exhaust gas in the cylinder for EGR instead of circulating it through the exhaust, EGR system, and back through the intake. "EGR" would be a misnomer in this case.
I love Mazda's ingenuity and passion for thinking outside the box
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 ?
That's one sexy ICE. I like the ability to blow the chamber squeaky clean without spitting fuel in to the exhaust system. The injection system is also a good idea. With the right pump it would allow to burn just about whatever in the chamber. You can run LPG, CNG, Diesel, Petrol, Alcohol, synthetic fuels, paint thinner, whatever doesn't dissolve the seals. Now let's see if Mazda can make a promising production model.
A small engine like this in a EV to extend it's range sounds good.
Unnecessary to do that.
@@MichaelWashingtonAE Not true. Adding a range extender reduces battery size
If it is a normal 2-stroke, the stroke until the exhaust port opens is considered for measuring the legal displacement.
This type of engine does not have an exhaust port on the side, and the intake and exhaust valves are open for about half of the piston stroke, so I am interested in how the legal displacement will be measured.
Utter rubbish. The exhaust port height has no effect on capacity.
@@howhistory5877 I think he is confusing compression ratio with capacity. Even that is open to discussion lol
Where I'm from we use bore X stroke = displacement.
@@richardcloudbase Wrong the swept volume ABOVE the exhaust port in a conventional 2 stroke is it's displacement. Neither you or HOW has a clue.
@@howhistory5877 You don't have much a clue do you...
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.
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.
What ever it sounds like its still better than any ev.
Diesels don't have a fixed 15:1 Air Fuel Ratio (8:41). The air fuel ratio varies depending on how much fuel is injected, which is controlled by the rack position. Unlike an Otto cycle gasoline engine, there is no throttle to control intake air flow on a typical diesel. Power output is controlled by varying the amount of diesel injected, resulting in a variable air fuel ratio. This is why diesels had high NOx issues to deal with before the advent of emissions control systems; lot's of nitrogen in the air fuel mixture at high combustion temperatures promotes the production of oxides of nitrogen, which in turn contribute to SMOG when mixing with un-burnt hydrocarbons and reacting with UV from sunlight.
This "new" two stroke technology is very similar to the Detroit Diesel Series 71 series engines (6V71, 8V71, etc, 71 cu-in per cylinder), which were first produced in 1938. Production stopped in the mid 1990s because of problems controlling emissions issues with the engines
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👍
Curious what cylinder pressure is during low rpm detonation compared to normal power stroke of a diesel,regardless will require extreme bottom end ,I would try on large cid if were able to have variable valve timing
7:19 is wrong.
The camshaft rotates 180 degrees for 1 revolution of the crankshaft... hence, the crankshaft has to rotate 2 turns (720) for every 1 turn (360) of the camshaft.
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.
Did you find this patent? 2-stroke engine with an intake port on the side and an exhaust valve on the head?
Awesome! They invented something already invented.
The basic 2-stroke engine with reed valve crankcase induction is the absolutely simplest engine yet devised, even with spark ignition. Take apart any old chainsaw engine and be amazed; piston, rod, and crankshaft. Holes in the side of the cylinder for exhausting spent gases. Now comes Mazda complicating something already perfect.
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.
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.
With a long stroke, it should provide high torque at relatively low rpm, especially since every stroke is a power stroke. This seems that it could be a good idea especially for a working truck, or bus. These are applications where high torque is paramount to get a heavy load moving. Perhaps they could blend a fuel that is higher in cetane and lower in octane and bump the compression ratio and get more fuel mileage from this vehicle. With elecronic controls on the valve timing, direct fuel injection timing, and spark timing, I could really see the advantages of this engine. I wonder instead of a roots type supercharger if they could incoporate a belt drive into a turbocharger where it is driven by the engine at low rpm and exhaust heat at higher loads. Something to think about.
The amazing part of this illustration, for me, is that no one presenting it noticed that the supercharger is running backward. The incoming air travels around the rotors, not between them.
The illustrated process would put a vacuum on the combustion chamber, not the pressure required to clear the combustion gasses and fill the cylinder with a fresh charge. Your CGI programmers need a basic course the internal combustion engine.
The narrator states that in normal four cycle engines, that the cam shaft rotates 360 degrees in half a crankshaft rotation. Even the script is backward. The cam shaft in a four cycle engine rotates at half crankshaft speed.
As for sound...some big Cummins diesel pickups have a low rumble you feel as well as hear: so that but maybe twice the frequency
Absolutely amazing video! Super cool! Unused exhaust reused without turbo genius
2 stroke, a power stroke for EACH piston stroke.
Would make a great motorcycle engine.
makes a nice truck engine too.
So is this going to require the making of a gasoline exhaust fluid instead of DEF to keep the NOx down from using the egr which is going to cause lots of extra heat?
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
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.
I came up with an almost identical system. I was going to start with a McCullough chainsaw motor. Beef up the lower end and weld a pad in the combustion chamber to raise compression.
It was going to be a combination of a roots turbocharged induction, fuel injected diesel.
I planned to run an alternator at a constant RPM. Charge a bank of lithium batteries, drive an electric motor in an electric scooter.
I got COVID, diabetes, CKD, afib, overweight, difficulty walking.
I became houseless. Got chewed up and spit out by thieves, tweakers,recyclers and landlords.
I guess that you gotta have a big corporation backing you in order to invent.
Can reed valves cope with diesel engine pressures? I've only seen schematics but reed valves look delicate.
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
all that is, it's a 4cycle I.C. engine with the camshafts timed 1x1 with crhankshaft and a roots blower shoving a charge inside. I've often wondered why no drag racers have tried this with a small block chevy. Would be an easy cheat, other than the engine sounding like it's at 8000 rpms from hitting on every downstroke
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.
Just curious as to what will happen if you add some suction device on the exhaust stroke?
The benefit of the old two stroke was always more power from a limited space for the motor. That space efficiency was due almost entirely to the lack of a valve train, and no need for external compression, but this engine requires both. What removed two strokes from the streets was the combination of lower fuel efficiency, and added (and more visible) pollution from oil premix/injection, but these have both been alleviated by this design. It seems like it might have a fit in some segment, but I'd like to see a torque curve from a prototype before guessing which segment. I can't wait to hear what these will sound like - hopefully better than Mazda's rotary engines. Hopefully this turns out to be a significant advance - we haven't had major advances in ICE since quad valves, fuel injection, and turbos decades ago, and electric with current battery tech required at least 50 more years of mining and infrastructure to be viable.
The ICE is past its sell by date.
The only so called problem with modern teal 2 stroke engines like the ones they run in ktms and the ones they run in sleds. Is emissions laws. The power to weight raito and mpg ate very efficient.
Stihl has been using a similar tech for years now. But this is genius. The only thing not mentioned was how much crazy heat this engine would surely make.
It will never see mass production 🦕
General Motors in WW2 had a Tank engine that was 2 stroke supercharged. Most people think 2 stroke is just add oil to the fuel and no valves in the head, but as this shows you can have a valved 2 stroke. This would burn very cleanly and produce a lot of power.
Didn't Mazda try with the rotary motor many years ago! It was so long ago I remember reading about it in the weekly reader in grade school. It never took off and was a flop.
G'Day..what is "Sky Active tech,??"Have a mazda 6 with Sky Acyive G, tech..can not seem to find any thing on the difference in these motors,
did find some thing on piston design that allows up to 16:1 comprsson ratios,again like diesel tech with a seperate combustion hole? in the piston,,
reckons fill with air and then fire injector to make 16:1 ratoi,,bit clever i say..
but i must agree with the earlier comment on diesel design,,
my other thought was with all this extra bang,,how much heavier do we make cranks shaft and things to support this exra bang we is gunna get,??
Great explanation! Can't wait to see it.
The valves would need to very big, esp.exhaust ones, hence even more prone to valve float (as cams would run at 1x crank speed).
Therefore, only with a Desmo valvetrain would this engine really work well and at the needed RPM for proper efficiency.