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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.

2014 Rogue kicks off production as 10,000,000th Nissan built in Tennessee

News comes across our desks all the time of one manufacturer marking some milestone or another. But Nissan has just announced a double-whammy: Not only has Nissan's assembly plant in Smyrna, TN, just built its ten-millionth vehicle, but that ten-millionth vehicle just so happened to be the first Nissan Rogue to be built in the United States.
The milestone arrives after over three decades of production that has included such nameplates as the Sentra, Altima, Maxima, Leaf, Pathfinder, Infiniti QX60, Xterra, Frontier, and now the Rogue. The latter crossover has swelled into Nissan's second best-selling vehicle, with demand growing by nearly 50 percent from 2010 to 2012. Now redesigned for 2014 and built locally, Nissan is evidently banking on demand continuing to rise.

2014 Nissan Dayz Roox is the littlest high-roof van you ever did see

Even average production cars from Japan often seem very conceptual to US eyes. Throw in typical, nonsensical-quasi-English-words name like "Dayz Roox" and you'd be forgiven for thinking this Nissan box on wheels was still a designer's dream. But the fact is that the Nissan Dayz is a model currently on sale, and this Roox version is the latest take on the micro-van, which is a popular segment in Japan.
In fact, this generation of Dayz is the first minicar that Nissan has developed completely in-house, and the thing has been selling astoundingly well in its first stint on the market (30k units in month one month, says Nissan). So it's unsurprising that the company is looking to expand the range with a model that is more fully featured.
The Roox (we have no clue as to where that name came from, or what it means) would appear to be a high-roof version of the three-cylinder Dayz minicar - in fact Nissan goes so far as to call it an "Impressive Super Height Wagon." Features like automatic sliding doors, Around View Monitor and UV-insulated glass are all luxuries in kei-class car. The press release also specifies that the Roox is tall enough to swallow a 27-inch bicycle.