Saturday, March 30, 2013

It's SkyActiv!!! Wait...what?

Most of you know that I am the Internet Sales Specialist at Gem Mazda, in Tallahassee, FL.  While specializing on selling the entire internet is time consuming, I do occasionally sell a car or two.  When it comes to new Mazda vehicles, the question I get asked more than almost any other is..."yeah, SkyActiv...what is that?".

The way I heard it told (or at least how I play the movie in my head), is the Mazda executives went to the engineers and told them:
  • You must make the Mazda3 hit the 40 mpg mark.
  • You may not sacrifice power.
  • You may not take shortcuts, like "eco" buttons or high profile tires.
  • You may not sacrifice safety (okay, that one's obvious).
Easy, right?  Well, if it was so easy, why is it that Mazda's competition did some of the following to hit the 40 mpg mark:
  • Used smaller, less powerful engines.
  • Have an "eco" button that takes power away from the engine to limit fuel consumption
  • Use high profile tires that detract from the vehicles' handling
  • Not include a spare tire to save weight (an inflation kit won't do much for a shredded tire)
  • Or even have procedural errors in determining the mpg's.*
So, how DID Mazda do it?  
(WARNING - The following is a little bit technical and long, but still interesting).

The Sky-G Engine
  • Direct Fuel Injection - Many cars are fuel injected, but Mazda used a multi-hole injector port (6 actually) that sprays the fuel into the cylinders at high pressure.  Think of it like a garden hose.  If you just have the end open when the water is coming out you waste a lot of water.  However if you put on a shower type nozzle, you increase the pressure of the water, and there is less waste.

  • High Compression Ratio - A 14:1 compression ratio (13:1 in the U.S. version due to 87 grade fuel) results in more power (torque) for the fuel being used.  If you get more power out of each say ounce of fuel, you are increasing the efficiency of the fuel burned.
  • Volcano top piston - Mazda added a volcano-like pocket at the top of the dome of the piston to allow the spark to...well spark, with excessive heating of the top of the piston, meaning that the energy of that spark doesn't dissipate over the top of the piston, reducing loss of energy.  Less energy lost, means better combustion of the fuel, allowing for a more efficient use of the fuel, again.

  • 4-2-1 Exhaust Manifold - A high compression ratio usually results in a thing called "knock" in vehicles that don't use higher grade gasoline (93 or better).  Knock is pre-ignition of the fuel that is the result of a rise in the temperature of fuel/air mixture from the previous combustion cycle.  Mazda wanted the SkyActiv engine to be able to run on regular ol' 87 grade gasoline however, so they used the 4-2-1 exhaust to allow for the combustion heat from the previous cycles to be removed, so they don't impact the following combustion cycles.  Told you it would get technical.
  • Electric Sequential Valve Timing - Very simply, making sure the valves open at the exact point for maximum power and fuel economy, with minimum emissions.  Otherwise you may have energy loss through unnecessary air movement in the intake system.

The SkyActiv Transmissions

SkyActiv-Drive (the Automatic one) - Mazda used the best aspects of the the traditional step transmission, the Continuously Variable Transmission (CVT), and the Dual Clutch Transmission, in developing the new 6-speed SkyActiv Drive Transmission (see the chart - from Mazda Fuel magazine).

The benefits include:

  • Better torque-transfer over a 5-speed automatic resulting in 4% - 7% increase in fuel economy.
  • Direct feel (more like a Manual transmission) in how it drives
  • Smooth upshifting
  • Rev matching downshifts
  • Improved fuel efficiency from reduced slippage in the torque converter.
  • Minimal Noise, Vibration, and Harshness (NVH).

SkyActiv-MT (the Manual one) - The story of the MT is simpler, but no less impressive.  Like the engine, they reduced the weight while making the materials stronger, and reduced internal friction.  The real benefit for those of us that enjoy driving manual transmission is the shorter shift-throws in the new MT.  The goal of the engineers was to make it feel like the iconic Mazda MX5 Miata.  They ended up with a 45-mm throw for that quick Miata like shifting.

SkyActiv Body - Through the used of more 50% more high-tensile steel throughout the redesigned frame, the SkyActiv Body is 30% more rigid, 8% lighter, and even safer than the previous incarnation.  The result is a lighter, but safer body that contributes to the fuel efficiency of the overall product.

SkyActiv Chassis - The diagram will give you all the information you need, but I will add the following:  New suspension geometry, electric power steering (EPS), more rigidity and 14% less weight keep in line with the other components in reducing weight, while improving performance and fuel efficiency as a result.

So, that's SkyActiv.  It's way more info than I would convey to a customer on the lot, but perhaps they'll read this and get a better understanding of what I meant when I said, "It's a whole bunch of little things, that add up to better fuel efficiency, without sacrificing power or performance."  For more information, check out MazdaUSA's official website for SkyActiv info.

Until next time, the SkyActiv is the limit!!!

(Much of this information came from the Summer 2012 Mazda Fuel Magazine, so thanks to Mazda for great vehicles, and the information).

* LA Times Article

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