Skyactiv-X: Mazda’s Revolutionary Engine Explained

Compression ignition in a gasoline engine has been seen as the holy grail of engine technology by many engineers and for 2019 Mazda has finally made it a reality. While some may say that SPCCI (Spark Controlled Compression Ignition) isn’t true compression ignition I disagree. Mazda’s engineers took a pragmatic approach to the issues surrounding compression ignition and instead of fighting the spark plug, they embraced it to solve the issues other companies encountered when trying to make this work. If all goes to plan this engine will be found under the hood of a Mazda you can actually buy next year.

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Alief Faisal says:

E85 can replace the petrol… Not much worry anymore…

Christian Lanctot says:

I like this explanation. Now, what does this do in terms of numbers? MPG? 0-60 etc. ?

Christoff87 says:

Amazing technology but I feel it’s just a few years too late as the industry seems to be heard towards electrification.

Henry Pacheco says:

Will the Mazda engines be reliable?

Andrew Valdez says:

bmw x2 review soon?

Paul Peterson says:

Does this engine have a glow plug like a diesel?

Euardo Acosta says:

Long run Unproven technology

Joseph Tolman-Lopez says:

You know you’re baddass when your trainers and shirt match

panic jib says:

The much needed change for an IC Engine. Hope it works smoothly…

Casa Del Amo says:

hot air motor from Smokey Yunick was far less complicated and much more efficient

Chris Ng says:

Hope its coming to cx 3 1st, intersted in buying suv now

Cqwet Dbdfte says:

You keep using “explosion” in your presentation. You better Google some facts about the internal COMBUSTION engine. No explosions, that would be very bad.
Moreover, does the car get 50 mpg? Henry Yunicks patent describes this almost 40 years ago in a patent. Look it up. Vapor phase engine.
You cannot burn a liquid. A mist from a spray is a bunch of droplets. Only the gas on the surface of the droplets will burn completely. The exhaust should have no hydrocarbons, only water and CO2. If an engine has a catalytic converter it means the combustion was incomplete. Thus the external “combustion” is needed. The heat is just another waste.
If you run a internal combustion engine at typical rpm’s with no spark, say with an electric motor you can easily measure the pumping losses. These will never go away.
You forgot to mention that disel fuel has more BTU/lb. These engines also have longer stroke, for more torque at the expense of RPM.
If diesel fuel was converted to a gas state it could be burned like gasoline. The change of state from liquid to gas requires added heat, not a problem in a combustion engine, and the gas will then have a pressure higher than atmosphere, which Henry Yunick kept in place with a turbine acting as a check valve.
Look at a primus type kerosene lantern, no smoke and no smell, and the liquid is thoroughly gasified before burned.
Even some types of diesel engines has a pre-mix chamber pointing to this.
If this new engine is so much better, what is the Mpg?

Relebogile Mothomogolo says:

Gasoline… Petrol

dougjstl1 says:

Okay let’s talk about the car man the car in the engine everybody knows about gas and Diesel man that’s the second time tell us a difference between gas and Diesel come on you talk about gas and Diesel wants gas and Diesel twice everybody knows gas everybody knows diesel come on the engine man the engine the car in the engine they won’t let you look at it will they they won’t let you lift the hood or nothing

dougjstl1 says:

We see you the car in the side man use your hands give us a hug let’s see that hug use the hands we can’t buy that we can’t buy this we got to see you on the knee the sign and the car use the hand give it a Patty pat pat

N S says:

One of the best motor channel’s on Youtube, Alex you do the best in explaining! keep it up!!

Leando Poullos says:

only now that they started to get serious developing higher efficiency gas engines, sad
but who knows, with all EV on the market in the future, gas prices will be so temptingly low,
sell these units cheap coupled with cheaper operating costs , there will be market for this for next 20 years

7A says:

somewhat like a fuel/air bomb

Alief Faisal says:

I Dont understand… 🙁 must study a lot more…

Renee says:

Any idea about what the miles per gallon will be on this? My 2016 MT Mazda 3 can get close to 38-39 on the highway and usually is around 30 with mixed driving. That’s really good for a gas engine. Also I love driving Mazdas! So much fun.

First Last says:

OTOH: their old MazdaSpeed3 just sodomizes this engine *SO HARD*. This engine’s sphincter is gaped so hard, you can hear the wind whistle as it goes by. Just don’t slip on the anal blood trail left behind.

Schalk Loots says:

Too late Mazda…where are your EVs?

jdamage68 says:

why? Just go electric.. Such a waste of engineering and resources.. I’m not impressed..

dano says:

thank you!

laith alwedyan says:

Ok lets say that they will put this engine tech inside the next gen mazda 6 after 3 or 4 years from now so they got some time to get more power out of this engine, lets say 200 or 210 hp (for now it generates 190hp)
Then combine that with a mild hybrid tech just for a little bit more efficiency and to produce more torque where needed,
then make it a full hybrid car
While keeping it light since it will use the newer chassis of the mazda
Idk what would be the cost of making this or if it can be done in the first place
But eventually u will have like 240 or 250 hp with a mpg that might be better than a prius
And ya mazda’s design !!

dougjstl1 says:

You didn’t say anything about the car or the ancient tell us about the D diesel on the gas everybody knows about Diesel and gas man show us what’s in the car what’s in the engine what’s it doing you don’t even know what they do is they adjust the valve timing of the intake to increase the compression on low-power like it idle or cruising you get more efficiently in the fuel but on a powerstroke you want to reduce that compression ratio when you need the power believe it or not it sounds opposite counterintuitive you won’t really in that car driving it

George Stone says:

Is high octave required?

James Pak says:

did this guy actually say “ignitiate”

WolfoxBenny says:

The future of Carbon on valves now also pistons with holes. That is why it was not done before because lean fuel mix will make a hole in your piston heads. Plus i hate “Auto detonating sound” And this will make feel uncomfortable. I still have to get used to the Direct injection noise……………Terrible!!


wankel engines

xchopp says:

Oh it’s “SkyActive” all right: just not in a good way. Combustion has to go.

ef def says:

The reason why we can’t just crank up a standard gasoline to the high compression levels we find in diesel engines must be else than that if we try to operate more of the traditionial diesel cycle then as we’re injecting the fuel it wouldn’t start burning as soon as it was injected.Cetane number is an indicator of the combustion speed of diesel fuel and compression needed for ignition. But the cetane rating of gasoline is very, very low. So gasoline wouldn’t start burning as soon as it was injected.

EnlightenedSavage says:

Free radicals are the biggest problem with preignition.

David Laurie says:

If its Mazda it wont work, at least for very long They are the idiots that tried for 40 years to make a rotary engine durable enough to compete with piston engines after NSU, GM, Ford, American Motors, Suzuki and even Mercedes Benz FAILED.

matt g says:


Quassir Williams says:

Sorry to say but you are wrong kind sir it was Peugeot who did this 1st and I can prove it and bare in mind I have seen it done with the coil pack unplugged but I will admit the running of the engine was not smooth and there is 1 little key trick that Mazda did not do that everyone is over looking also that I am sure will eliminate that spark plug totally Mazda has part of it correct and Peugeot has the other part correct it’s jus the 2 combining both technologies and boom the spark plug is extinct

paveldaddy says:

I would love to see a combination of skyactive X and a CVT transmission with plug-in hybrid like some Lexus cars

Al Castillo says:

Conclusion buy a diesel

joseph bourdeau says:

This has been in F1 engines for a while now . Some systems actually use two injectors , one to inject fuel into the cylinder and one to inject fuel into a small chamber enclosing the spark plug .

First Generation off the Farm says:

Detonating. He mixed fuel and air and used the turbo as a “homogenizer” and superheated the air and fuel and it worked fabulous! 350 horsepower and 80 plus miles to the gallon out of a 2.2 L 4-cylinder!!! I wonder why they didn’t buy it from him…….

David Jebson says:

Hi Alex, thank you very much for this video. If I understand this correctly, this engine is using some of the principles of the Atkinson cycle engine, to provide for variable compression ratios. Interesting but ultimately I believe we will all be driving battery electric cars very soon.

Ben Griffin says:

Wow, these reviews all sound so similar, as if all the talking points had been handed to the various reviewers, I don’t know, maybe somewhere around negotiating payment for said endorsement….
So how much does this kind of review cost/pay, anyway?

Mike Schmauss says:

Developing a new ICE? What is their next act, a new and improved buggy whip?

dougjstl1 says:

I like it you the car in the sign use your hands man use the hand get on one knee let’s see you the car in the side of the car yes we can’t get it can’t get this we can’t get that we can’t buy it

Deploracle says:

The unending quest for maximum efficiency is kind of yesterday, when we honestly thought the supply of petroleum was limited. It’s not, at all. More oil today than ever before in Earth’s history. If we don’t do something with it we’ll be knee deep someday. Burning it produces plenty of CO2 which plants and trees need to prosper.

First Generation off the Farm says:

Smokey Yunick had this perfected on a Dodge 2.2 in an Omni in 1992. An engine runs best right before it is

Butch Tyrone says:

Good explanation, very simple.

kitkat224 says:

cool, what about figures? if it’s doing 35mpg keep it we don’t want it

crazywaterz says:

The ENTIRE auto industry, including the trolls in the comments, are clueless and talentless AF. What kind of bozo-school they got their “engineering” degrees from, seriously?
Just because you haven’t seen a modern engine design YET, doesn’t mean it doesn’t exist. Back in 2012, I’ve invented a hybrid and fuel agnostic engine with only 3 moving parts, at half the size, volume, weight, cost that puts this PoS and any engine created the last century into shame, while producing zero NOx and I still struggle to get the retards of the industry not just to adapt my design, but barely meet me to see that it works. The masses expect the factories to be innovative. You are so collectively dumb if you think they want to do it. The only reasons they come up with incremental improvements is competition, free grands from your tax money and pressure from governments and buyers for “new” models. They would still sell you steam engines that run on coal if they could get away with it. And electric cars are NOT 100% clean. No technology is. Stop worshiping Elon like a God, he’s still using rocket tech from the 40’s to go to orbit. Not to mention that with fully electric cars, you always carrying half a TON of dead weight like an idiot, charged or not. Forget about batteries. The future is in capacitors. You are all delusional. Educate your ass and open you minds. There are ways to get 80%+ efficiency with ICE, if you know how.

bjorn1583 says:

as long as a spark plug is used to ignite the fuel it is spark ignition not compression ignition

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