2002 Nissan Frontier 4x4 Crew Cab 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 gives us the business on the art of clay modeling

The team from The Dashboard recently stopped by the Nissan Technical Center in Japan for a look at what exactly goes into creating a full-scale clay model. While automakers have been using clay bucks for decades, designers and engineers are now combining computer renderings and hand-sculpted clay models to determine how a new vehicle will look in our world. Engineers use specially formulated clay kept warm in an oven to bring the body panels to life. They then coat the clay in a thin plastic film to add body color for the final look.
By the time everything is said and done, workers may have hundreds of hours in the model's creation. So, what happens when the company no longer needs the buck? They get scrapped. Someone comes in and dismantles the whole creation. We presume that action is set to the wailing tears of everyone who had a hand in building the model. Check out the video below for a closer look.

Nissan happy with plug-in vehicles for now, will wait on hydrogen

Anyone who's driven the Nissan Leaf knows that it won't set any land speed records. Still, ask Nissan Vice Chairman Toshiyuki Shiga, and the battery-electric vehicle will be miles ahead of any hydrogen fuel-cell vehicles for the foreseeable future in Nissan's advanced-powertrain plans. Figuratively, of course. Shiga, speaking in Singapore, elaborated on Nissan's interest in developing a production hydrogen fuel-cell vehicle, and, to put it bluntly, he said the company didn't have much interest, the Japan Times reports. Sure, Nissan reached an agreement with Mercedes-Benz parent Daimler and Ford early last year to work together to speed up fuel-cell-vehicle powertrain development. Like Toyota, Honda and Hyundai, the automakers appear to be following the axiom that hydrogen fuel-cell technology is the best-of-all-worlds option for advanced powertrain because of the combination of zero emissions and conventional-vehicle-like full-tank range. Still, the prohibitively high cost of building hydrogen refueling stations will prevent any substantial adoption anytime soon, Shiga says, hence Nissan's focus on battery-electric vehicles. Nissan sells the all-electric Leaf in about 40 countries, and the model is the best-selling battery-electric vehicle in the world. In the US, Nissan sold 24,411 Leaf vehicles through October, up 35 percent from a year earlier.