2012 Nissan Maxima on 2040-cars

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Auto News Recap For 5.13.16 | Autoblog Minute

Senior Editor Greg Migliore recaps the week in automotive news, including a look at Hyperloop One's desert propulsion test, Chrysler 300 rumors, and Nissan's purchase of Mitsubishi. Chrysler Mitsubishi Nissan Autoblog Minute Videos Original Video hyperloop

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 Nissan Juke Nismo RS amps up the funky crossover

Nissan unveiled an even hotter version of the hotter Juke Nismo at the Los Angeles Auto Show - the Juke Nismo RS, a 215-horsepower crossover that may be the most hardcore model in the compact CUV segment (until we can convince Mazda to build a Mazdaspeed CX-5, that is).
The 215 hp and 210 pound-feet of torque represent bumps of 18 hp and 26 lb-ft over the standard Juke Nismo thanks to a revised ECU, a new exhaust with a larger diameter tube, and stronger connecting rods. This amped-up engine can be mated to the owner's choice of a six-speed manual, which takes advantage of a stronger clutch cover and dual-mass flywheel, or an Xtronic continuously variable transmission (although the CVT model loses four horsepower and all of the extra torque that the Nismo RS enjoys).
"We expect drivers to feel a noticeable increase in acceleration - especially the manual transmission model - in the RS versus the regular Juke Nismo. It also holds peak torque longer. Combined with the Helical Limited-Slip Differential, which helps reduce torque steer, the sense of driving excitement is unmatched in the Juke lineup," said Pierre Loing, Nissan's vice president of product and advanced planning and strategy.