Wednesday, November 14, 2012

CVT - The Elastic Waistband of Transmissions

First conceptualized in the 15th Century by DaVinci, the continuously variable transmission is not a new idea.  While automotive applications date as far back as 1896, the first truly practical and reliable systems were developed by Dutch manufacturer DAF in the late 1950's.

CVTs have seen a resurgence of late, thanks to more advanced materials engineering allowing for their use with more powerful engines, and the rising importance of fuel economy.  Like elastic waistbanded jeans, CVTs are very efficient, stretchy, cheap to manufacture, and will make you feel like an absolute tool.

This man drives a DAF Daffodil

While recently on vacation in Chicago, I rented a 2013 Nissan Altima four cylinder equipped with one of these hateful contraptions.  The gist of how it works is this - you step on the gas, the engine buzzes straight to 2,500 RPM and then stays there forever.  Regardless of incline, load, or how far you push the accelerator, the motor rarely changes pitch - the only variable being when initially accelerating on a light throttle, the engine would hover just off-idle at about 1,300 RPM while simultaneously emitting a sound not dissimilar to my Basset Hound when he grinds his teeth in anticipation of a meal.  It never doesn't feel awful.  Imagine pedaling a bicycle equipped with a rubber band chain and you're not far off what it's like - which to reiterate is horrible.  If this is the future of converting internal combustion into forward motion it honestly makes me thankful for the impending electrical sanitization of the automotive landscape.  Ugh.

Here's a video depicting how belts and pulleys are responsible for so much unpleasantness.

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