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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.

Infiniti EV delayed to add better tech

An evolution in lithium-ion batteries and "interesting advances in electric technology" are said to be responsible for the delay of Infiniti's electric car, the production version of the LE concept first shown at the New York Auto Show in 2012. At the time of its introduction, Infiniti said we'd have a version we could buy within two years; that timeline became 2015, and now Automotive News Europe reports that it's"still within in our mid-term plan" but officials aren't saying how long the delay will be.
When shown, the LE had a 24kWh lithium-ion battery and a 100kw electric motor producing 134 horsepower and 240 pound-feet of torque, a 100-mile range and the potential for wireless charging. It isn't clear if the postponement will bring improved specs or perhaps improved packaging and technology - or both. All we have for now is that the new timeframe is "not significantly" beyond the original plan.

2014 Infiniti Q50 sees 3,650 pre-sales ahead of Aug. 5 debut

Infiniti's answer to the hot new sports sedans from BMW, Cadillac and Lexus is creeping closer and closer to its August 5 arrival in dealerships. And while we yet can't pass judgment on the Infiniti Q50 - formerly known as G37 - 3,650 Americans are apparently ready to, as they've already raised their hands for the 2014 model.
In a pre-sale program announced at the 2013 New York International Auto Show, Infiniti gave buyers until June 30 to raise their hand for the new model. "The Infiniti Q50 pre-sale exceeded all expectations, becoming the most successful such program in Infiniti history," according to Infiniti's American Vice President Ben Poore.
A lot is expected of the Q50, available in both rear- and all-wheel-drive and with an optional hybrid powertrain. With 328 horsepower from its 3.7-liter V6 engine, Infiniti is making sure the new car packs a big punch relative to the competition. Meanwhile, the Q50 Hybrid offers fuel-sippers 360 ponies and up to 36 miles per gallon.