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Infiniti's new VC-T changes the rules of small turbocharged engines

The upcoming Infiniti QX50 crossover does not get our pulse racing, no matter how shapely the QX Sport Inspiration concept that previews it may be. No midsize SUV does, to be fair. But it has something special under the hood – the world's first production variable-compression-ratio engine. That means the QX50's 2.0-liter turbo four, which makes 268 horsepower and 288 pound-feet of torque, will have up to 27 percent better fuel economy. Here's how it works. The trend of moving to smaller, turbocharged engines carries with it one big falsehood. Under low load when the turbo isn't needed, these engines are less efficient than an equivalent engine without a turbo because of the low compression ratio the turbo requires. That is, if you never need the extra power, you're wasting fuel. Turbocharged (and supercharged) engines use a lower compression ratio to prevent detonation. When you force extra air in a cylinder and mix it with fuel, it's more likely to prematurely go boom. Lowering the compression ratio prevents this problem, but it's less efficient. Infiniti's VC-T promises the best of both worlds, with a compression ratio that ranges from 8.0:1 for high-power turbo needs to a 14.0:1 ratio for fuel-sipping efficiency. At its heart the VC-T engine is a simple idea, but it's complicated to explain. Consider yourself warned. The photo below from Infiniti serves as a good visual overview. For the truly nerdy, this patent application covers the mechanical concept. Instead of having the pistons connected to the crankshaft, Infiniti's engine has a pivot arm with a connection on each end. One end connects to the piston, the other connects to a second lower shaft, which is controlled by an actuator arm. At any given time the engine's pistons move up and down according to the lobes on the crankshaft. But the actuator arm can change the angle of the pivot arm up and down. That is, the pistons still move in the same motion with the same stroke, but phase the entire stroke up or down. Move the pivot up and there's less room at the top, which means a higher compression ratio. Move the pivot down and the compression ratio goes down, too. As an added bonus, the lower shaft eliminates the need for counter-rotating balance shafts. Infiniti says this system works constantly and can vary the compression ratio to any number between 8:1 and 14:1. It also uses electronic variable valve timing on the intake valves to switch into Atkinson-cycle combustion for greater efficiency.

Why China will soon lead the electric vehicle market

China could be the world's largest electric vehicle market by 2020, thanks to significant government subsidies and the major drawbacks of owning an internal combustion model there. The country's populace registered 75,000 EVs in 2014, and sales figures in 2015 looked even better. In a new video, Renault-Nissan examines the trend and why it happened. Chinese cities heavily encourage buyers to go green through vehicle incentives, but they also make it a hassle to be a polluter. In some places, there's a lottery to limit vehicle registrations and alternating driving bans for even or odd license plate numbers. However, these limits don't apply to EVs, and the country's automakers have benefited from the regulations by introducing small, inexpensive electric models, albeit with sometimes hilarious styling. China's emissions regulations will get even tighter in the coming years. In fact, a Honda exec recently predicted the company wouldn't be able to sell any models there without some form of electric assistance by 2025. Get a better look at the country's electric push to clean up vehicle pollution in Renault-Nissan's video. Related Video:

Nissan Leaf battery cells put through torture test, live to charge again

One minor chink in the armor of the Tesla Model S is that a small number have caught fire, once their battery packs were penetrated. Nissan Leaf drivers, however, might just be able to weather such an event without an ensuing CarBQ. Our evidence for such a claim? A video that has surfaced of cells from a Leaf pack undergoing a battery of torture tests (pun somewhat-ashamedly intended). Shared by folks at the Hybrid Auto Center in Las Vegas – who offer for sale, among other things, used Leaf lithium battery modules – the footage shows salvaged cells being brutally assaulted with a screwdriver, and later, a propane torch. Granted, these tests are not the same thing as flinging a piece of metal into a working pack at 70 miles per hour, but they do claim to show that a puncture does not always equal a fire. Oh, and don't try this at home. When pierced through by the flat head tool, there is no explosion or eruption of flame. Instead, a rather modest wisp of smoke shyly emerges as the electrolyte next to the shorted area of the fully-charged foil pouch reacts with the influx of oxygen. Again and again, the blade descends, until the cell is riddled with holes. No fire. Amazingly, when connected with a voltmeter afterward there are still plenty of signs of life, and when it is charged and discharged (off-camera), it reportedly suffers only a slight loss of charge capacity. The video goes on to show another cell attacked with open flame with similar results. While the demonstration is, perhaps, somewhat crude, the message it sends is loud and clear: lithium batteries can be safe and rather robust, despite some freak accidents. Scroll below to watch the short presentation for yourself. This content is hosted by a third party. To view it, please update your privacy preferences. Manage Settings.