2021 Nissan Rogue S on 2040-cars

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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.

Nissan Juke facelift spied during testing

The Nissan Juke boldly reinvented the subcompact crossover for the modern age a decade after the niche's progenitors - the first-generation Toyota RAV4 and Honda CR-V - grew well beyond their original, diminutive sizes. Since being introduced in 2010 as a 2011 model, the Juke has proven to be a huge sales success for Nissan in Europe and quite a success here, too. A modest refresh is planned for the 2015 model year of Nissan's tiniest crossover, and our spy shooters have caught an early glimpse.
The exact changes are not easy to spot, but you can bet that anywhere you see camouflage, a modestly new look is hidden underneath. The biggest change up front is the narrower grille that appears to no longer extend over the headlights. Assuming this isn't just a clever disguise, the change gives the impression that the Juke actually has distinct headlights, instead of massive fog lights. The more angular front air dam also appears to extend slightly lower than before, and the intakes appear to be revised as well.
The changes to the rear are even more minor. You can still see the outlines of the boomerang-shaped headlights, and any alterations to the rear bumper are impossible to spot behind the camouflage tape. It's also unclear at this point whether the interior will receive any refinements or new options.

Nissan's Cummins tie-up bears first fruit with Frontier Diesel Runner concept

The 2014 Chicago Auto Show is proving to be a surprisingly big show for alternative fuels. The Chevrolet Silverado HD pickups are getting a compressed natural gas option and the refreshed BMW X3 is receiving a diesel engine, as is the German automaker's 7 Series. You can add one more oil burner to the mix, at least in concept form: Nissan has released its Frontier Diesel Runner Powered by Cummins with a 2.8-liter, four-cylinder turbodiesel engine and an eight-speed automatic transmission from ZF.
While Nissan calls the Cummins-powered Frontier a concept, it's really just a Frontier DesertRunner 4x2 with a diesel engine replacing the standard 4.0-liter V6, and it's meant to gauge consumer interest for a diesel option in the next-generation Frontier. Nissan has clearly noticed that Chevrolet will be offering a diesel in its new Colorado and wants to see how buyers will react to a mid-size alt-fuel pickup from a Japanese brand.
Exterior modifications to the concept are minor. To show off the engine, there is a transparent hood insert and the pickup has been painted in a two-tone finish of high-gloss red and matte silver edged in carbon fiber trim. The interior gets the same combo of red, silver and carbon fiber to match the outside.