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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.

A look inside Infiniti's variable-compression engine

We're sympathetic to anyone who had trouble understanding what's going on with Infiniti's new variable-compression engine. While we got a full tech briefing on the novel VC-Turbo back in August, the visual aids were lacking. The cutaway engine Infiniti brought to the Paris show fixes all of that. You can thank the little green and pink lines on the cutaway for making the whole idea a little more clear. Click through the gallery to see two lines – one green and one pink – that represent the different strokes allowing for different compression ratios. Remember, the compression ratio is the amount of volume in the cylinder on intake compared to the amount at the end of the compression stroke. Leave more room at the end and you lower that ratio. The length of the stroke doesn't change with this system, but where it sits along the cylinder does. Hence those two lines. The variable compression ratio allows this new turbocharged engine to maximize fuel economy when the turbo isn't needed by raising the compression ratio. It will see its first use in the next Infiniti QX50 crossover, previewed by the QX Sport Inspiration concept that's also on display in Paris, and has performance targets of 268 horsepower and 288 pound-feet of torque. After, it will migrate to other Infiniti and Nissan vehicles, with transverse front-drive-based applications first in line. Eventually, it's likely to completely replace Nissan's corporate 3.5-liter V6. We'll be poking around the engine a little more in Paris today to try and get some more info. For now, enjoy those cutaway images and those friendly little lines. Featured Gallery Infiniti VC-Turbo engine cutaway View 14 Photos Paris Motor Show Infiniti Nissan Technology Emerging Technologies engine 2016 paris motor show

2014 Nissan Altima gets updated equipment, prices

The fifth-generation Nissan Altima is heading into its second year, and to mark the occasion, it's getting updated pricing, some visual and tactile enhancements and new option packages. First up are the physical changes: All 2014 Altima models will have chrome exhaust tips, revised seat cloth (when not fitted with leather) and better noise isolation. Check the option box for the new Sport Value Package, and the Altima also will come equipped with 16-inch aluminum alloy wheels, a rear spoiler and remote engine start.
But those aren't the most important updates for 2014. Nissan is showcasing the expanded functionality of its NissanConnect system, which works with Android and iPhone handsets. Applications will be introduced in the fall and launch with Google search and Facebook, later to be joined by iHeartRadio and Pandora. NissanConnect with navigation system (separate from NissanConnect applications) will be capable of running SiriusXM Travel Link for data including weather, fuel prices and movie times. In addition, there are changes to other option groups, including a revised Technology Package and a new Display Audio Package, the specifics of which can be found in the official release.
As for pricing, the changes are pretty minimal, with the base 2.5 CVT starting at $21,860 and the full-boat 3.5 SL CVT topping out at $30,660 before options and a $790 destination fee. You can compare those figures with 2013 pricing here, and see the full rundown of all the trim level prices by scrolling below.