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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 to give Qashqai the Nismo treatment

Nismo is on a bit of a rampage lately. Once consigned to the fringes, Nissan has taken its performance sub-brand into the mainstream and let it loose on a whole mess of its products. The Juke Nismo was followed by a 370Z Nismo, and in Los Angeles, we saw the GT-R Nismo, Sentra Nismo concept and Juke Nismo RS.
So what's next from Nismo? According to the latest intel from across the pond, Nissan is working on a tuned version of its new Qashqai. Car magazine is reporting that the larger crossover will get the same 1.6-liter turbo four as the Juke Nismo, but with the RS model's 212-horsepower out and not the "base" model's 197. Expect all the other bells and whistles applied to transform a Nissan model into a Nismo one to apply as well.
If the Qashqai name doesn't ring any proverbial bells for you, that's alright, because it's only sold overseas, where it's one of Nissan's most popular models. The crossover (which looks like the new Rogue but is a substantially different model) was recently completely replaced, with engine options ranging up to 150 horsepower - so the jump to over 200 should make for quite a different beast altogether. Whether a parallel or subsequent program to give the Rogue a similar treatment is another matter, but given the pace at which Nismo seems to be running, that may only be a matter of time.

The Scoot Quad is Nissan's small step toward EV car sharing

Halfway up Laguna Street, the panic set in. I might not make it up this hill. With my foot depressed all the way to the floor, I sucked in my stomach and started to pray. Yet again, I found myself in an unconventional way to get around on four wheels – but this time, I was on my own, and behind the wheel. Meet the Scoot Quad, aka Nissan New Mobility Concept, aka Renault Twizy. The many aliases reflect the path of descent from its development as a quirky French electric vehicle to its proliferation as a model for car sharing. The Quad resides in San Francisco as part of the Scoot fleet of shared electric vehicles and it's most certainly not for sale. As the line blurs between those who share cars for personal reasons and those who use them for business purposes, Scoot and Nissan came to an agreement in which a small number of New Mobility Concepts would join the Scoot fleet – which currently includes over 300 motorbikes. The added value of Scoot is the capacity for one-way rentals around the city, as well as a dedicated network of charging stations. "We think it's just the best way to get around the city for everyone," said Scoot fleet vice president Mike Waltman, explaining how 10 New Mobility Concepts made their way to San Francisco. Charging time is about four hours on a Level Two charger, made possible through Scoot's network of stations around the city. The one-plus-one Twizy has been in production since 2012 and on sale in certain overseas markets, but it's entirely new for the United States, and it wears the Nissan badge here – kind of. No major changes were made to the Twizy when it became the New Mobility Concept, and similarly none were made in its "transformation" to the Quad. It sports the same insectile shape and the rear profile of a top hat, as well as an identical powertrain: a 13-kilowatt motor that produces 17 horsepower, routed to the rear wheels through a single-speed automatic transmission. Charging time is about four hours on a Level Two charger, made possible through Scoot's network of stations around the city. Its top speed is 50 miles per hour, but Nissan installed a governor at 25 mph to conform to US low-speed vehicle requirements. New Scoot members are required to successfully pass an exam before beginning to use the service, so that was my first order of business. After spending about 35 minutes going through a series of informational videos on the Scoot app, as any new member would do, I was ready to ride Scoot motorcycles.