2011 Nissan Maxima on 2040-cars

Auto blog

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.

Bug-eyed next-gen Nissan Titan spied testing

It's no secret that the fullsize pickup truck market is dominated by offerings from Detroit's Big Three automakers, the Nissan Titan and Toyota Tundra not able to outdo the Ford F-150, Ram 1500 or Chevy Silverado/GMC Sierra twins. A great deal of that has to do with the fact that, while the American trucks have all undergone evolutionary updates that include a range of body styles, fuel-efficient engines and excellent technology, the Japanese offerings are, well, really old. Toyota is offering an updated Tundra for the 2014 model year, and while we haven't driven it yet, we're already betting that it's still behind the pack in terms of competitiveness - the 2013 model placed fifth out of sixth in a recent PickupTrucks.com comparison test.
At the bottom of the pack lies the Nissan Titan, a truck that hasn't received any sort of substantial update since its introduction nearly ten years ago. But that's going to change - a new truck is slated to debut for the 2015 model year, and these spy shots of a Titan mule clearly show that things are moving forward.
While this tester relies heavily on the current truck's bodywork for testing purposes, the new Titan will have a revised design, some of which is evidenced by the bug-eyed front fascia of this mule. No, the production model isn't going to look all weird (we hope), but the higher, more outboard headlight placement suggests that the new truck will be a bit wider than the current model.

Nissan-Renault mule teases mysterious subcompact

There's always something intriguing about a mystery, especially of the automotive kind, and that's exactly what we have here. Our spies recently spotted this Nissan-Renault test mule on the road in Southern Europe. But what, exactly, are they testing? From the front end, it's clear this mule started life as a Nissan Versa Note, but check it out in profile to see the cut down rear doors. They're significantly shorter than on the production car, and the wheelbase isn't as long here, either. The tacked on fender flares suggest a wider track than stock, too. Making things even more complicated is the bizarre cladding this subcompact hatch is wearing. The odd tumors on the hood and blistered side panels indicate that the automaker is trying to keep the design underneath a secret. Given Renault and Nissan's tight relationship, it also isn't clear which company is testing this model. While the body comes from the Note, this one is wearing French license plates. According to our spies, the vehicle was also spotted leaving a Renault testing location. There are some possibilities, though. Renault already has the new Twingo out, and the next-gen Megane has an imminent release. The French brand could now be at work on a future Clio. Alternatively, Nissan is reportedly using the Sway concept as inspiration for the upcoming Micra, and we could be getting a preview here. Give us your best guess in Comments. Related Video: