http://altairenlighten.com/wp-content/uploads/2011/12/Mazda-Skyactive-lightweight.pdf
My mind is still spinning after looking at this (drunk)
My mind is still spinning after looking at this (drunk)
Need more information then you really need.
- Thread starter JohnJr
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- Mazdaspeed6
Excellent little tech manual. Thanks for sharing that!
Nice summary outlining the many differences between Skyactiv and the competition. The benefits of Skyactiv technologies like a light, rigid chassis and direct feeling automatic transmission provide a sophistication to the driving experience that is probably lost on the typical Neanderthal-type American motorist who might prefer the isolation of any real world feedback and a "hydroglide" type transmission. But everyone can appreciate and understand fewer $$ at the pump.
Some are quick to point out that "Skyactiv" is just a marketing term (which is true) but that ignores the fact that it stands for a suite of leading edge technologies and design philosophies that provide significant advantages over the competition. I am interested to see how well the CX-5 fares in more demanding crash testing in comparison to the competition (such as small offset frontal crash tests which have not yet been performed). Consumers like to consider all vehicles that get the highest ratings in the basic tests as equally safe but nothing could be further from the truth. The crash tests are not as severe as many real world accidents and I think the Mazda stands a good chance of doing exceptionally well in more severe testing/accidents. You never know when someone is going to rear end you at 60 mph while waiting to make a left turn.
In any case, I thoroughly enjoyed looking over the summary and results of the Skyactiv design philosophy - thanks for posting!
costermonger
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- CX-5
dad of jon
Member
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- cx-5 se-l 2.2D
x2
I've read the document last year and it is a good one. Page 20 has an important description of delayed intake closing. Basically this gives a longer expansion stroke than compression stroke and is known more generally as atkinson cycle although Mazda uses the term miller cycle (which more commonly refers to the same principal for supercharged engines like the previous Millenia). This is a very interesting bit since a higher compression ratio engine can offer more power and torque but also has higher pumping losses. Closing the intake valves late lowers the pumping losses when off the throttle (less deceleration) and gives much higher fuel economy in low throttle, low load operation.
The higher compression ratio truly offers more hp/torque at lower rpm than similar size engines of other makers. As an example, the new Toyota Rav-4 has the same displacement 2.5L engine but it's peak torque is at 850rpm higher than the CX-5 peak torque.
Another interesting thing is the increased fuel rail pressure (almost 3000psi) for the skyactiv engines. I noticed this from the CPU data I see on my torque app but it will be interesting to see if there will be any long term issues due to the higher pressures.
The higher compression ratio truly offers more hp/torque at lower rpm than similar size engines of other makers. As an example, the new Toyota Rav-4 has the same displacement 2.5L engine but it's peak torque is at 850rpm higher than the CX-5 peak torque.
Another interesting thing is the increased fuel rail pressure (almost 3000psi) for the skyactiv engines. I noticed this from the CPU data I see on my torque app but it will be interesting to see if there will be any long term issues due to the higher pressures.
