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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 NV200 Mobility Taxi adds a dose of accessibility to the new-look cab

Nissan has been making hay with its NV200 light commercial vehicle in New York. We've known since last year that the van will see service as a taxi in the Big Apple, and more recently, we learned that a variant will be kicking around to rescue ailing Gibson guitars. At its press conference this year, Nissan continued the onslaught with a wheelchair-accessible version of its NV200 Taxi.
The automaker has teamed with BraunAbility - a company that styles itself as the world's largest maker of wheelchair-accessible vans - to create this NV200 Mobility Taxi. The cab features a fold-flat ramp for rearward wheelchair accessibility, as well as a restraint system to keep said chair snugly in place at speed.
In addition to showing off the Mobility Taxi, Nissan announced at its press conference that it will be making both hybrid and fully electric versions of the NV200 Taxi available, as well. Scroll down for the Nissan press release, or take some time with our extensive live and stock image galleries of the NV200 Mobility Taxi.

Nissan Leaf all-electric taxis start pilot program in NYC [w/video]

When New York City picked the Nissan NV200 as its Taxi of Tomorrow, many were surprised that the vehicle wasn't electric, or even a hybrid for that matter. With NYC Mayor Michael Bloomberg on hand, Nissan celebrated Earth Day on Monday by unveiling a pilot program of electric taxis for the city consisting of six 2013 Nissan Leaf EVs, which the mayor referred to as the "taxi of the day after tomorrow."
This pilot program is aimed to show how EVs can operate as taxi cabs, and Mayor Bloomberg said that New York City hopes to have a third of its taxi fleet electrified by 2020. In addition to the six cars, Nissan has also provided three quick chargers around Manhattan, allowing the Leafs to get an 80-percent recharge in just 30 minutes.
According to David Yassky, commissioner of the NYC Taxi and Limousine Commission, "What we have to do now is figure out how you integrate the charging of an electric vehicle into the duty of a taxi cab."