skyactiv, skyactive, mazda
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Mazda Skyactiv High Compressin direct injection engine

13:1 Compression and 40 mpg on 87 Octane fuel?  Introducing Mazda’s Skyactiv Technology

By Mike Kojima

Does the idea of a super efficient, reasonably performing, fun to drive car with low operating costs sound appealing to you?  If the car is green as well does that seal the deal?  Are you one of the few people with a clue that realizes that a hybrid isn’t all that green? Well Mazda has an answer to all of this called Skyactiv technology in all of its clever jinglish.  Skyactiv Technology is a fresh holistic look at how cars are engineered.

mazda skyactiv engine

Skyactiv technology is primarily engine related, but it also incorporates the concepts of weight reduction, improved chassis stiffness and crash resistance, improved transmission function, and improved handling.  We will talk about Skyactiv’s compelling gasoline engine technology, known as Skyactiv G today, and will discuss the remaining aspects of Skyactiv technology in future articles.

Mazda Skyactiv Engine

Mazda’s goals for the Skyactiv G gasoline engine were many faceted.  By thinking totally out of the box, Mazda’s engineers have been able to create an engine that can run on cheap unleaded regular gasoline yet still acheive the fuel economy of a diesel and retain Mazda's class leading fun to drive performance.  Mazda has created the intelligent alternative to a hybrid with a much lower lifecycle cost, while being more fun to drive and not asking the customer to sacrifice performance during that lifecycle.

Mazda Skyactiv engine

mazda skyactiv engine
Let's take an inside look at the Mazda Skyactiv engine!

 

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Comments
JDMized
JDMizedlink
Friday, September 02, 2011 1:05 AM
Wow, nice article Mike.
Actually the Porsche GT3 RS also has 12.5:1 comp. (with Ti rods).

Anyway, those skyactiv piston's dome look trick.
The skirts are tiny, how about side load rocking? I'm sure Mazda has done tons of R&D on it, but to run such a high comp on 87 octane is pretty remarkable, the timing must be super retarted....lol

Thanks for sharing.
Motary
Motarylink
Friday, September 02, 2011 2:59 AM
I have been waiting for the article on this engine for a while now, thanks a lot for sharing and in such detail!
Jason
Jasonlink
Friday, September 02, 2011 4:57 AM
Love the article. I hope they will tune the computer to take advantage of 93 octane if one chooses to run it. Maybe a sport button or Zoom Zoom button for use with high octane :D
rawkus
rawkuslink
Friday, September 02, 2011 5:40 AM
I wonder if this engine would be more fuel efficient in my gen 1 Insight than the original hybrid system...
joelcrookston
joelcrookstonlink
Friday, September 02, 2011 7:30 AM
This is probably a silly question with such high compression, but is there any plan to incorporate forced induction to really kick it up a notch? I'm just curious because I know forced induction is being used to improve performance while impacting fuel economy less than more displacement would, but it doesn't sound like this engine was designed to be robust enough to handle the increase in cylinder pressure. Boy would it be fun though...
VP
VPlink
Friday, September 02, 2011 7:43 AM
I guess the knowledge and ideas could be shifted to a turbo engine. Maybe not this one or this one with lots of adjustments but low friction, direct injection, etc, etc could/should be applied to improve even further their eficiency!
Peter Medina
Peter Medinalink
Friday, September 02, 2011 8:00 AM
Really great article Miguel. If it can run 87 comfortably, then it can probably do 5-7 psi on 91 without having to change the compression ratio. Better yet, I wonder how much boost you can run on E85. However, at the end of the day, the boost limiting factor will be the light piston ring tension. It would be interesting to see just how much power loss there is in changing the PWM of the oil pump solenoid, vs being able to run a little more boost.

The part throttling trick is neat, and one of the reasons why throttles won't go anywhere for a while, even though they are barely "throttling" anyhow. At least until Fiat's Multi-Air matures and gets out-licensed to everyone else. Did the Mazda guys tell you if they are employing the Ford throttle control algorithm of WOT at tip in? 100% throttle is achieved in under 500 ms for pedal states as low as 15%. Maybe that's why you're getting some detonation.
Rockwood
Rockwoodlink
Friday, September 02, 2011 9:23 AM
@ rawkus: Probably. I think the majority of the Insight's fuel economy gains are from its aerodynamics and light weight, than from it's hybrid powertrain, at least until you get stuck in city/rush hour traffic. TDtuning swapped a 1.2L TDI engine into an Insight without the IMA working and got over 80mpg.

And Mike and Mazda's Skyactiv: bring it. ;-p
Sootfoot
Sootfootlink
Friday, September 02, 2011 9:40 AM
I’ve been following this new engine with much anticipation. I’ve been there and done that with the TDI and while it’s a very good engine the inherent flaws that Rockwood pointed out with the clogging of the intake manifold, expensive/complicated timing belt changes and higher parts costs have got me looking at the Mazda. I also don’t want to have to step down into a car like the Fit, Mazda2, or Fiesta to hit that 40 mpg mark. Thank you Mazda for taking the smart and efficient approach!
Micah McMahan
Micah McMahanlink
Friday, September 02, 2011 9:55 AM
It's funny to see this come up today as this morning I was having a discussion (really an engineering argument) in test cell of how I think gas/ethanol engines will end up replacing the small diesel market. With some of the newer technology stuff (see my upcoming interview in CA) I think diesel trucks as well. Glad to see the ball rolling and thanks for sharing, Mike.

I may have missed it but how much longer are the rods on this setup? I know b/s ratio has shifted and I can see the comp height is smaller as well.
Rockwood
Rockwoodlink
Friday, September 02, 2011 9:57 AM
@ Aaron: Parts costs have come down with a lot of competing online parts sellers. Showing up at the dealership is a reaming, sure, but that's the case everywhere. The timing belt job, while complicated, thankfully likely only needs to be done 3 or 4 times throughout the useful life of the car. ;-p

But yeah, there is a LOT to be gained in improving the efficiency of ye olde internal combustion engine. The heat energy balance graph on page 1 highlights where major strides can be made with the ICE. This new engine will also come in newer cars. Given the choice, I'd choose a Skyactiv Mazda 3 over a TDI Jetta. This engine is far less complicated, and the new smog requirements have made diesel engines a choice for powerband or being different, than for fuel economy unless you strip all the lame smog equipment.

BTW, I believe the MZR engines (and all DI engines, for that matter) have been having issues with intake clogging.
spdracerut
spdracerutlink
Friday, September 02, 2011 10:38 AM
On DI engines and intake clogging, I wonder if Porsche has figured it out. They're going DI on everything and they have a ton of experience from developing it for racing applications. Audi/VW has been doing DI for a decade too, and also developed from racing.
spdracerut
spdracerutlink
Friday, September 02, 2011 10:39 AM
@Peter, I don't think this engine can handle much boost at all. It looks to be optimized for efficiency which means making the parts as light as possible. Also the reduced journal bearing sizes. So I think it'd be like the first gen VQ35s that could barely handle any boost as they were optimized for maximum NA power.
destrux
destruxlink
Friday, September 02, 2011 11:00 AM
Really looking forward to seeing these engines in service. I read about these in the mazda pamphlet that was mailed out to mazda owners a year or so ago and was wondering how they managed to pull off the 14:1 compression ratio. Very impressive.
8695Beaters
8695Beaterslink
Friday, September 02, 2011 12:22 PM
What is this doing to the cost of the 3 and the other cars it's going into? It looks like a pretty clean-sheet design and those aren't cheap. I guess by spreading it to a bunch of different cars they plan to recoup the cost. Is there a stop/start feature or cylinder deactivation? Those have been simple ways to bump fuel mileage.

Looks impressive. Hard to believe how quickly things are moving along in the auto world. This motor looks almost unmodifiable, at least to the general public. Most of the power probably lies in retuning the ECU (which will probably be hard as hell and will lose some of the fuel mileage) or forced induction.
Mike Kojima
Mike Kojimalink
Friday, September 02, 2011 12:28 PM
This engine is pretty much at the limit of stable combustion and mechanical strength. It is very optimized. If you attempted to boost it, it probably would not be good. A 91 octane ECU reflash might be nice with japanese/euro market pistons! How about a dual mode ECU for higher octane fuel?
JDMized
JDMizedlink
Friday, September 02, 2011 12:29 PM
I JUST noticed the flywheel on the first picture (on the first page), it's a little hidden.
That thing looks light ! Happy zoom zoom indeed !
Mike Kojima
Mike Kojimalink
Friday, September 02, 2011 12:29 PM
According to the Mazda engineers, they have figured out intake clogging by controlling intake valve temperature. It says so in the story!
Micah McMahan
Micah McMahanlink
Friday, September 02, 2011 12:51 PM
So no comment on rod length changes :(
Also, did they increase the stroke on this? I'm unfamiliar with the engine family. I see the bore decrease that you mentioned. I think I need to re-read the article.
Adam
Adamlink
Friday, September 02, 2011 12:56 PM
Mike It's great to see Mazda accomplished this without forced induction like GM did with the LNF motor.
If it's possible it would be a great follow up story and get some insight into how all of this is managed through the ECU. If it's anything like many of the latest generation of high power ECU's, gone are the 2 and 3 dimensional tables.. all replaced with hundreds of coefficients that combine to produce engine operating models.
Rockwood
Rockwoodlink
Friday, September 02, 2011 1:41 PM
@ Khiem: With Porsche and their racing efforts, it's likely not a problem due to lower mileage and probably better fuel quality. Mazda's DI engines probably see a lot of ARCO. ;-p

@ 8695Beaters: Stop/start was not going on this motor for the US market because it has very little effect on EPA mileage estimates. IIRC, it would be a feature on Euro and Japanese models.

@ Mike: I was talking about farther up the intake manifold. The valves may be clear, but I remember seeing problems with MZR engines and intake manifold clogging.

@ JDMized: That's an auto-transmission flex plate, not a flywheel.

@ Adam: GM vs. Mazda in their attempts to make a 40mpg gasoline engine are po-tay-to/po-tah-to, IMO. I think I like the turbo trend more, maybe combined with some of the technologies in this engine, since it's a simple reflash away from butt-loads of power.

And yeah, these ECUs are practically becoming self-aware. The Bosch controller for the newest common-tail TDI is incredibly powerful.
Rockwood
Rockwoodlink
Friday, September 02, 2011 1:47 PM
BTW, in regards to hybrids and being "green", the thing that amuses me the most about that trend is the number of brand-new hybrids you see on the road, and the increasingly rare 1st generation hybrid. It's not very green to trade in a vehicle before you've offset the additional pollution from manufacturing your green transportation pod. I wonder what the percentage is of hybrid vehicles is that makes it to 150k miles before being retired.
bigdave
bigdavelink
Friday, September 02, 2011 2:35 PM
spiffy
8695Beaters
8695Beaterslink
Friday, September 02, 2011 5:09 PM
I remember reading some auto insider saying that people who own hybrids want everyone else to know they are driving hybrids. Most people who buy hybrids wear them like fashion statements. And they have to have the newest and trendiest one that's out there.

Me? I'd buy an Insight just to put a K-swap in it and go land-speed racing. Think of the records that little thing could shatter!
Mike Kojima
Mike Kojimalink
Friday, September 02, 2011 7:49 PM
Wait till you guys read about the Skyactiv D Diesel! 50 mpg and 300 ft/lbs! Kiss my Hybrid!
Matt
Mattlink
Friday, September 02, 2011 9:48 PM
dreams of a jdm spec 14:1 compression engine in a Mazda2 are ringing in my head.

If they did that oem i feel that they would have the hot hatch to beat
4agze52
4agze52link
Saturday, September 03, 2011 12:15 AM
Great article i ve been wanting to read about this new engine but wants the city MPG?
Der Bruce
Der Brucelink
Saturday, September 03, 2011 7:45 AM
Aaron - Don't let Steve fool you. Unless you can be fully commited to the DIY VW, it's spendy.

Micah - Um, nothing beats diesel BTUs! Gas still doesn't even touch synthetic diesel.

Steve - I may not like the spendy nature of the VW but you'd walk over the Skyactiv G. The Skyactiv G 2.0l has no where to go but 155hp and fuel economy could only be improved with aero and maybe chassis tuning. The TDI has no where to go but up in power and fuel economy. That is what I love about diesels, the only ICEs I know where you can actually improve fuel economy while adding power.

Mike - Excellent article! I started reading about this engine about two years ago, I think, and finally get a GREAT look at it. I LOVE the cut away shots. Now that's an inside look :) This motor was even rumored, once upon a time, to be headed for Miata duty.

Given a choice though, I'd take GM's 1.4 turbo or Ford's ecoboost before I went with the Skyactiv G or TDI. They'll be more tunable, when someone actually wants to?, and that BTCC Cruze is sexy!
Mike Kojima
Mike Kojimalink
Saturday, September 03, 2011 9:36 AM
They didnt tell us what the city MPG was but I assume it will be pretty good.

UPDATE, I just got invited to try a closer to production Mazda 3!
SixCylinders
SixCylinderslink
Saturday, September 03, 2011 10:37 AM
The thought of detonation in a stock motor bothers me. It is my opinion that an engine like this should not be hot rodded, granted my opinion on the VR38 was the same when it was first released. I do think that if it doesn't destroy its piston rings or ring lands in stock form that it will be a great engine for the majority of the population.
Rockwood
Rockwoodlink
Saturday, September 03, 2011 11:00 AM
@ Six: lots of stock engines ping. I was amazed at how much my buddy's TL Type S pinged on a warm day.

@ Der Bruce: DIY or GTFO. :)
Dave Coleman
Dave Colemanlink
Sunday, September 04, 2011 3:15 PM
To those who think there is no headroom on the Skyactiv-G, consider the following: the MZR 2.0 in the Mazda3 makes 148 hp, the same MZR 2.0 with slightly higher compression (0.8:1 higher), slightly bigger cams and a different calibration makes 167 hp. There is no doubt the Skyactiv-G engine is highly optimized, but at 155 hp on 87 octane and with a 6500 rpm redline, I would't write it off as maxed out.

Anybody else remember when the B18C1 came out and everyone said it was so awesome there's no way anybody could make more power from it?
Mike Kojima
Mike Kojimalink
Sunday, September 04, 2011 4:06 PM
It is maxed out as far as the limit of the fuel. Probably piston speed as well. Tiny crank journals and a crank with no overlap doesn't bode well for making gobs of power.
Dave Coleman
Dave Colemanlink
Sunday, September 04, 2011 6:06 PM
Maxed out on 87 octane, yes, but there's that other pump right next to 87 that costs 20 cents more...

I doubt its maxed on piston speed, though. Stroke is roughly 91 mm. That 8mm less than a K24 that revs to 7100 stock.

The Skyactiv-G's forged crank is supposedly at least the same stiffness as the MZR cast crank. The rod journals are the same size as the MZR (non-turbo), but the mains are smaller by 2 or 3 mm (can't remember).

So, yea, not big hulking Kojima gobs of power, but certainly enough more to be entertaining.
cloud81918
cloud81918link
Monday, September 05, 2011 7:22 AM
What is the likely hood of it making it into the 2012 Mazda5? We have looked at the Mazda 5 for a long time this would probably do the trick.
DaewooOfDeath
DaewooOfDeathlink
Monday, September 05, 2011 4:56 PM
This sounds very similar to the new, 1.6L Hyundai engines in performance and economy. I'd be interested to hear how Hyundai got the such a similar engine with normal compression and, I assume, less on the edge optimization.
speedball3
speedball3link
Tuesday, September 06, 2011 12:13 PM
It would be fun if they used the 14:1 version for a Mazdaspeed 2... I don't remember from the article, are there any physical differences between the 14:1 and 13:1 engines? Or is it all calibration? Interested in how a turbo version will be developed for the MS3 and CX-7...hopefully it maintains the same high level of engineering.

With the intake valves, how do they manage startup conditions when the valves aren't at 400 C? Or does it heat up pretty quickly so it doesn't really matter?
Der Bruce
Der Brucelink
Tuesday, September 06, 2011 1:31 PM
Dave - I certainly can't disagree with the logical points you've brought up, but I do worry about the physical limits of what's presented in the Skyactiv G. If no manufacturer is willing to R&D the aftermarket, then it'll run into the same lack of aftermarket support that other's like the Honda Fit or Nissan Versa have in the past. People will just have an effecient car that's cheap on gas and only the few will actually have ones that could go even remotely fast.
Micah McMahan
Micah McMahanlink
Wednesday, September 07, 2011 8:29 AM
@Der Bruce, trust me when I say I know tons about diesel. It's what I spend 8 hours day working on at the OEM level. Diesel's enemy is emissions and the added costs to make them pass.

@Dave Colemen: I agree that the engine has plenty more in it with a reflash and some better fuel. I however probably wouldn't want to try and put boost on the internals. I imagine the factor of safety wasn't too high on the engine due to manufacturing design.

I'd really like to see how this compares to the new Hyundai engine which my friends just drove to a wedding this weekend. Said they got 43.x mpg driving out.
Der Bruce
Der Brucelink
Thursday, September 08, 2011 11:30 AM
Micah - Diesel's real enemy is misunderstanding and misperception in this country! The 800lb Gorilla in the room, though, is California. If the OEMs decided to give Cali the bird, I think the other 49 states could have 6000lb+ pickups that actually get 25ish mpgs. I've said too much and I could say a LOT more.
Rockwood
Rockwoodlink
Thursday, September 08, 2011 12:24 PM
So goes CA emissions, so goes the country. Using PPM as a measurement (vice g/KM), is what also kills diesels and their fuel economy.
Micah McMahan
Micah McMahanlink
Thursday, September 08, 2011 12:35 PM
Der Bruce: there is no misunderstanding or misperception from the EPA or CARB perspective. The population, sure but being someone who types this from a diesel performance and emissions test cell...I love to hear what you know that I don't. I can easily go take a 6.7 Scorpion in a 9000lb F350 and get 25 mpg and make gobs more power, if I make it dirty and thus illegal.
The issue we have now is kind of like saying; you have power, emissions and fuel economy...pick two. Be it we are fighting tooth and nail to not give up performance while passing emissions and by keeping customers via better fuel economy.

Rockwood: Pretty much everything is brake specific, not ppm or g/KM.
Rockwood
Rockwoodlink
Thursday, September 08, 2011 1:13 PM
I'm certainly not an expert on this, but wouldn't brake specific be PPM, since you measure pollution per given quantity consumed?
Micah McMahan
Micah McMahanlink
Thursday, September 08, 2011 2:51 PM
pretty much, yeah...but it is brake specific for given test cycles.
Der Bruce
Der Brucelink
Thursday, September 08, 2011 10:58 PM
Okay, Okay. I thought ppm and g/KM were measures of polution aka particulates and brake specific was a way to measure fuel economy.

Micah - I love the pick two statement! Clearly you know your stuff, it's what you do. But since you challenged me to offer up something you might not know. Did you know that almost all "studies" mentioned by CARB don't actually have the studies listed to back it up? This may not seem signifcant to you but a former editor taught me, when reading scientific journals, to follow where their sources/studies came from. That's why those science oriented articles have a crap load of studies listed at the end to back up statements. I just think much of what CARB and the California EPA puts out reads more opinion than concrete fact. Just read their ZEV stuff lol!
Rockwood
Rockwoodlink
Friday, September 09, 2011 12:34 PM
@ Micah: PPM and Brake Specific allows/forces automakers to sacrifice fuel economy in the name of percentages, not the actual mass of pollution a vehicle outputs. This is how an F-150 is ULEV, despite putting out probably 2-3x the g/km of a Civic. A diesel also puts out considerably less g/km than an equivalent gasoline car, if they'd change the measuring standards, then you'd see cheaper diesels on the road.

As it is, in the case of the DPF/particulate mandates, we're sacrificing as much as a 50% penalty in fuel economy for as little as a 70% decrease in pollution on a PPM basis, resulting in not much of a decrease in actual output of pollution.

I couldn't care less if a diesel is comparatively dirty, if it consumes 50% less fuel and has a PPM output of 20% higher than that of an equivalent gasoline engine, it's still considerably cleaner.

@ Der Bruce: The studies themselves can be written by people with fake doctorates, and when that person is discovered to be a fraud, it's covered up until after it's voted on, then that person doesn't even get fired. Look up Hien T. Tran and CARB. All of this DPF stuff that's killing diesel efficiency, and pricing it out of the market to boot, is based on a study "Dr." Tran came up with and primarily turned out to be incorrect. Whoops.

Did CARB retract it? Nope. Did CARB at least fire "Dr." Tran? Nope, he's still there.
Der Bruce
Der Brucelink
Friday, September 09, 2011 1:16 PM
Excellent stuff Steve! What's funny, or sad, is that the three of us reflect the minority of people who actually realize the great resource that presents with diesel. Mazda has caught onto the growing VW TDI sales, which helped to get the Skyactiv D going. GM too, hench the latest rumor of a diesel Cruze to break the coveted 50mpg mark. But as a great man always tells me when we talk about these latest diesel rumors, "we'll see."
Rockwood
Rockwoodlink
Friday, September 09, 2011 2:27 PM
Yep. Like the 25-30mpg diesel SUVs and 1/2 ton trucks we were supposed to have 2-3 years ago...
Micah McMahan
Micah McMahanlink
Monday, September 12, 2011 12:44 PM
Rockwood: yes, I see your point about how PPM or brake specific limits in percentages. If you went by total mass of a vehicle however, how you mandate the pollution from a small engine vs. a large? Does a truck now have to fall under the same emissions/mile that a hybrid (don't get me started on the hate) would have to meet? Just having fun poking and provoking thought.

I actually had an engine go off for monkey killing per part of the gov'ts research on EATS effects on the environment. Not everyone thinks tiny DPF particles is a good thing ;)
Rockwood
Rockwoodlink
Tuesday, September 13, 2011 3:04 PM
Nah, you'd obviously have to allow for differences in vehicle size. Either that, or you allow manufacturers to trade credits like they do now.

Either way, I think we should always be more interested in the net pollution rather than how relatively dirty something is. This is the same reason why I think it's ridiculous that they banned leaded fuel in CA for hobbyists, but still allow it for aviation use. WTF?
Misnblu
Misnblulink
Wednesday, September 14, 2011 4:14 PM
Great article and engine. But 40 is what I'm getting in city/ highway driving in my Toyota Paseo, every day. I drive this car hard and rev it to 7k and still with all the abuse it's getting consistent 40+ mpg with a little bit of tuning that didn't come from the factory.
Although it only weighs 2000 pounds without me in it, it's something that I enjoy bragging about with all these high tech cars that seem to think that 40mpg on the highway is really something special.

I'm also hoping that this isn't the engine that is or has replaced the Rotary in Mazda's lineup. And is this the same engine that is being used in the ALMS LMP1 class Mazda that constantly gives the fits to the Aston Martin V12?

Rockwood
Rockwoodlink
Thursday, September 15, 2011 7:36 AM
@ Misnblu: Excellent point. However, your car doesn't have the same emissions and crash standards as the newer cars do, which has cut into fuel efficiency.

I highly doubt this engine will either replace the rotary, nor be used in ALMS.
Misnblu
Misnblulink
Thursday, September 15, 2011 4:46 PM
Thanks Rockwood.
I'll further research the engine that is used in the Mazda's LMP1 car as it sounds so good on the rev. :)
Misnblu
Misnblulink
Thursday, September 15, 2011 4:50 PM
Quick research yielded this and not to be off subject but this was my curiosity when I'd read this article above and now know the difference. :)

'Building on their successful partnership with Mazda, Advanced Engine Research has built a race winning version of the MZR-R engine that represented the state of the art in turbocharged engine technology. The 2.0 liter, four-cylinder in-line turbocharged engine was designed from a clean sheet of paper, and is designed to make in excess of 500 HP - on a per cylinder basis, more than an F1 engine. It is all aluminum construction and is mounted as a semi-stressed member of the chassis with A-frames.'
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