Mazda Creates The Holy Grail Of Gasoline Engines - HCCI SkyActiv-X

Japan : "let's think of a new way to make engine more efficient and eco-friendly" Europe : "ugh, let's lose one more cylinder and add another turbocharger"

Take it from a competitor - Nissan calls HCCI “the highest potential heat efficiency among internal-combustion engine systems” and “the ultimate combustion method for achieving both CO2 reduction and clean exhaust.” This is big news that we’ll see it in a production car soon! Follow along on Instagram: www.instagram.com/engineeringexplained/

Knowing nothing of engines, and going based on the pictures alone I assume gasoline engines run on lighting bolts, diesel engins run on fire and HCCI runs on magic.

Deisel efficiency without blowing cancer into the lungs of all the baby children. This really is big news. My hat off to Mazda, mighty effort.

Was in Hiroshima a couple of weeks back and speaking to one of the Mazda staff about this engine. They stated (and it was repeated in their release video YouTube: wEh8MgFLNh8) that the work they did for their clean sheet approach to the Skyactiv-G and Skyactiv-D engines was intended as the path to this Skyactiv-X engine. Of course with those, the non detuned G had a compression ratio of 14:1 (very high for gasoline) and the diesel had the same compression ratio (14:1 very low for diesel). The diesel follows on from numerous studies of low compression diesel using a single cylinder (Example "A Survey on Low Compression Ratio Diesel Engine" - Bridjesh P et al) where there was lower NOx and soot, however cold starts were an issue. Mazda sorted this out by redirecting exhaust during startup (I experience this daily because I have a Skyactiv-D, and even on the coldest mornings it takes just a few minutes to warm up where you cannot exceed 50km/h). The bonus however has been lower NOx and lower soot. Both of these were illustrated recently. Japanese government investigations into diesel engines post VW dieselgate, showed that Mazda's engine was the only engine to meet standards and had NOx emissions as stated in both real world and laboratory tests, whereas all other manufacturers had between 6 to 10 times more that the standard when comparing real world tests to the lab. With regards to deposits, AutoBild in Germany Dauertest (which is an intensive 100,000km test), came to completion on a CX-5 with the Skyactive-D, they noted no deposits on the cylinder (which contrasted greatly to the 18:1+ also in their Dauertest. The other advantage to lower compression has been weight. The old Mazda 18:1 diesel had an iron block. So the question I posed when in Hiroshima was what compression ratio the Skyactiv-X would be. The answer was simple.... what compression ratio have both G and D been heading towards? The answer - 14:1. Watch the Mazda video on youtube wEh8MgFLNh8 and this is basically hinted.

This news just came out like 2d ago. Can't believe how fast you got this video out

What happened to Koenigsegg's Free Valve technology? It has a lot of potential as well

Thank you for this high level explanation. Essentially, it runs in normal Skyactive mode with a spark plug unless conditions are optimal (low load, not extreme external temperatures) and it switches to compression/heat. It makes perfect sense they (Mazda) is not sharing specifics, but your explanation makes it pretty clear.

Jason - by supercharging, I think mazda means a compressed air injection system. it's still 'super charging' but not in the way we think. I presume they'll accumulate compressed air in a cylinder, similar to volvo's compressed air turbo spooling system but instead of dumping the air into turbo exhaust turbine, mazda will directly inject it into the cylinders. that way they can make very precise alterations to the air fuel ratio based on feedback from fuel quality sensors and change the effective compression ratio on the fly; even providing different amounts to each cylinder if necessary. HCCI is quite sensitive to pressure, temperature and fuel quality so this flexibility and granularity will be very helpful.

just imagine how awesome a HCCI Freevalve engine would be

Sustainable zoom zoom for the much honor of Japan.

Currently have a Skyactiv-G Mazda3. 4 years old, 4 Canadian winters and the engine still purrs like a kitten, even after the front end was smashed in an accident. Seems like a solid engine thus far so I trust Mazda to perfect this design and not rush things.

The year zoom zoom 2030, where the boomy boom engines were made more efficient for the vroomy vrooms

I want a straight six with this tech

Thanks for the interesting tutorial. You always do such a great job of conveying your thoughts with a clear and concise explanation.

First thing I thought was there'll be issues with engine failures if one little thing goes wrong. So basically if one component fails, it will be a catastrophe for the whole engine. I suppose the fail-safe will be the spark plugs......... which will be useless in a lean running engine because of premature detonation, and holes in the piston crown. Looking down the thread seems like many will agree. But here's an idea. Instead of borrowing $50,000 for a new car, then chasing your tail to pay it off. Why not buy a used car for under $5000, with a fuel efficient engine, it'll use 30-40% more fuel but cost $45,000 less. If you spend $5000 overhauling the engine and transmission over its lifetime, you'll have saved $40,000. Then there's accrued interest, which offsets any 30-40% saving in fuel on the newer car. Then there's the amount of energy that goes into making a whole new car and the emissions that causes. Recycling existing cars by restoring them and retro fitting more fuel efficient engines will actually save more on crude oil usage. So lets be a society that is concerned about fossil fuel usage, and keep throwing away this energy on creative destruction, and then throwing away the savings to fossil fuel usage on creative destruction.

Bring on the sustainable zoom zoom! I've managed to get the sustainable part nailed (converted all the fuel lines and seals on my turbo diesel so I can run waste veggie oils) but I don't even have 1 zoom :( Two zooms is the dream! xD

Yet another timely, interesting video from EE. Jason deserves all of his 1.3M subs.

Dude your videos never cease to amaze me. I love how far in detail you go with each and every video. The simplicity of a white board and pictures in your videos have educated me a whole lot. So I'd like to thank you for your very educational videos and keep them coming! This stuff that Mazda is trying to do is freaking crazy! Like who would of ever thought of such a thing?

Mazda is the leader when it comes to mechanical engineering. My 2016 CX-5 has of course the Sky Activ 2.5L engine, dual clutch auto trans. and AWD. I have gotten 35 mpg during xway driving. Awesome!