Wednesday, March 7, 2012

Better boom for the zoom zoom

Mazda has always been known for their sporty, well performing, yet affordable cars. From the small Mazda 3 to one of their biggest vehicles, the CX-9, they all seem to offer the driver a very enjoyable driving experience. But in a world where “efficiency” is becoming increasingly important, is it even possible to go fast and use less fuel at the same time? The answer is yes. Many companies have recently introduced new technologies that give their vehicles more or equal power while increasing fuel economy. Mazda calls their new technology Skyactiv and they claim it has given their vehicles a 15% increase in fuel efficiency and torque. So how did these Japanese geniuses accomplish such a feat? The secret lies in the high compression ratio in their new engines.

Now the more research I did the more complicated everything got so I’ll try to avoid most of the mumbo jumbo and just give you the important parts. Most engines have a compression ratio of 10:1 which means that when the piston is at the top of its stroke in a 1000cc combustion chamber, the chamber has been reduced to 100cc. Hence 10:1. The new Skyactiv engine has an impressive 14:1 compression ratio.The reason a larger compression ratio is such a good thing is because it enables the engine to use more of the energy that it produces. This better use of energy is what causes the boost in torque and fuel efficiency. So why doesn’t every company use these high compression engines? Well with the increased compression comes the added risk of engine knocking. Engine knocking is when the air-fuel mixture ignites too early due to the higher temperatures and pressure within the combustion chamber. Mazda came up with some creative solutions to this problem including a 4-2-1 exhaust system and piston cavities. These help reduce the temperature within the chamber so that ignition occurs at the exact time it needs to.  Enough with the technicalities, the important thing is how much torque and what kind of fuel economy these new engines produce. The new 2.0 liter Skyactiv engine puts out 148 lb-ft of torque and can get up to 40 mpg highway. That’s not a bad increase from the previous 2.0 liter which produced 135 lb-ft of torque and only 33 mpg highway. With their new Skyactiv technology Mazda has given me a renewed hope that the future won’t be full of just Toyota Prius’ and Nissan Leaf’s, but that we might actually be able to maintain the joy of driving a sporty car while also achieving fuel efficiency.

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