A look inside the Mazda Skyactiv engine

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Sorry if this has been posted before. I did not see it. Here is an in depth look at the internals of the skyactiv engine.

http://www.motoiq.com/magazine_articles/...technology.aspx

The main reason I'm posting it is because it talks a bit about what Mazda thinks is the culprit for the DI deposit issues and what they did to try and mitigate it.

EDIT: The link goes to pg 6. there are 7 pages on the engine.
 
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I test drove a few CX-5s with the SkyActiv engine, and rode along with a test drive on a 3 with SkyActiv.

They seemed to ping a lot. I guess that's what happens when you run such high compression on 87?
 
Mine never pings *shrugs*. Neither did the CX-5 I test drove.
 
I have to question all the tricks used to reduce friction...no piston skirts,narrow main and rod bearings,narrow rings.....I'm thinking this engine is going to burn oil and knock something fierce once the miles pile on.
 
They haven't got a clue till warranty claims come in whether they solved DI problems either.
 
Originally Posted By: rjundi
They haven't got a clue till warranty claims come in whether they solved DI problems either.


They have been making DI engines since 2006. I couldn't find any reports of deposit issues. Have you found any? I'd appreciate the info.
 
Article actually mentions deposits specifically:

Quote:
One of the biggest issues with direct injection engines is a build up of deposits on the intake valve. Mazda determined that this was largely due to the intake valve being too cool. A lot of analysis went into designing the heat paths away from the valves to keep them at the proper temperature to avoid deposit formation.
 
Originally Posted By: NHGUY
I have to question all the tricks used to reduce friction...no piston skirts,narrow main and rod bearings,narrow rings.....I'm thinking this engine is going to burn oil and knock something fierce once the miles pile on.


I think I agree. Worse, if it starts to burn oil, is this going to run worse than regular, lower compression engines?

I don't doubt that Mazada has done their homework; but I'm reminded that their home market is not all about high-milage engines. Engine life at 200kmiles? Is such a thing a factor in their design guidelines?
 
Thanks for posting this.

Just FYI, the Skyactiv-G in the Mazda 3 has "only" 12:1 compression due to in adequate space for the exhaust header used in the CX5.
 
I think the oil pump design is pretty cool and props up my thoughts that this engine may be pretty easy on its oil. The pump design combined with the overall friction reduction should yield nice, long OCI's, especially with Mazda's oil.
 
Originally Posted By: NHGUY
...no piston skirts

Clearly there must be minimal skirts on the faces radial to the pins, not shown in the cutaway. It can't work geometrically otherwise.
 
Originally Posted By: badtlc

They have been making DI engines since 2006. I couldn't find any reports of deposit issues. Have you found any? I'd appreciate the info.


Check the Mazdaspeed boards; stock or modded the intake valves get covered with grungy deposits. A lot of guys have deleted the EGR valve and/or added an oil catch can to prevent the buildup.
 
Originally Posted By: Kiwi_ME
Originally Posted By: NHGUY
...no piston skirts

Clearly there must be minimal skirts on the faces radial to the pins, not shown in the cutaway. It can't work geometrically otherwise.


skyactiv-g_img_03.jpg


Yes, and the skirts look coated. Looks like steel, too!
 
Guess I'm gonna find out. I truly do not want to keep a car as long as I kept my last one - 23 years, 355,000 miles. There is such a thing as unnecessary worry.
 
Anyone else notice the looooooong spark plugs?
Man, if those stick - forget it!

I see no new tricks. This is a compilation of ideas that have been around. Short skirts, low tension rings, roller rockers, etc. have been around for decades.
Even the variable valve timing which allows high compression is from the last century.

Run the intake hotter? This may help in one area and hurt in others.
D.I. is a problem that won't go away.
 
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Nothing "new" here, just a nice focus on efficiency at many levels.

That piston is not steel, it's aluminium and would be coated in the skirt area for sure. Note that many of these "features" are found on cars back in 05.

Mazda is doing more marketing than anything, at least they consider chassis dynamics. Many FWD platforms don't seem to care about the driving experience, just the infotainment!
 
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