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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.

NA auto output to reach 11-year peak

According to Automotive News, automakers are expected to manufacture 16 million light vehicles in North America in 2013. That's up 500,000 units from last year and marks the largest number since 2002. The prediction comes courtesy of LMC Automotive and IHS Automotive, which point to the improving US economy as a bellwether for total production. LMC Automotive says North America will produce 16 million vehicles while IHS has a slightly more optimistic forecast of 16.1 million units. A total of seven automakers are slated to increase production on the continent this year. Nissan is set to see the largest jump at 20 percent over last year.
Volkswagen, meanwhile, is one of the only manufacturers predicted to scale back production. Analysts expect the German company's output to fall by 23 percent to 170,000 units, thanks in part to slow demand for the Volkswagen Passat and Jetta.

NHTSA investigating 200,000 Sentra, Versa models over brakes

The National Highway Traffic Safety Administration has opened a second investigation into Nissan in May. The first covered inaccurate fuel gauges in the 2007 Quest minivan. The latest affects the Sentra and Versa from the 2013 and 2014 model years and the 2014 Versa Note, because of complaints of long brake pedal travel. If NHTSA finds a problem, it could affect an estimated 200,000 vehicles.
At the moment, this is still only a preliminary evaluation "to asses the scope, frequency and safety-related consequences of the alleged defect," according to the report, but it could lead to the full recall. NHTSA is still trying to find whether or not there are accidents, injuries or fatalities related to the problem. At this time, much of the data in the document is still marked Confidential or TBD. Nissan told Reuters in a statement that the company is working with the agency on the investigation and supplying the regulator with further information.
According to NHTSA, its Office of Defects Investigation has received eight complaints about long pedal travel in these models. They allege that the brake pedal goes all the way to the floor when pressed in some cases and doesn't sufficiently slow the vehicle. Autoblog has contacted Nissan for its reaction to the investigation. We will update this story when we receive a reply. Until then, scroll down to read the current investigation report.