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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 recalling 909k vehicles globally over accelerator issue

Nissan is issuing a massive recall that will see the Japanese automaker repair 908,900 vehicles worldwide, with nearly 100,000 of the affected models in the United States. While an official recall notice from Nissan or the National Highway Traffic Safety Administration is not yet available, Reuters has been able to confirm the recall with Nissan.
Nissan's recall is kind of the opposite of the Toyota unintended acceleration, in that it covers a lack of acceleration. According to the report, a sensor in the gas pedal can develop faults, leading to a sluggish acceleration or an outright stall regardless of how much throttle the driver dials in. The huge recall covers mostly Japanese domestic models like the Serena, X-Trail, Lafesta and Fuga, which make up for 764,800 of the 908,900 faulty vehicles. However, 98,300 Infiniti M sedans are being recalled in the US, although it's unclear at this time which model years and trims are affected. The remaining vehicles are found in Europe and Oceania, according to Nissan spokesman Chris Keefe.
No injuries or accidents have been reported due to the faults. The 90-minute repair will see techs replace the accelerator pedal and tweak the engine control programs. We'll update this story as soon as Nissan or NHTSA makes an official statement.

A beautiful conundrum | 2017 Infiniti Q60 First Drive

"OK, this should be fun." Hands are rubbed together excitedly. It's a rear-wheel-drive sport coupe painted candy apple red. It's sleek, slinky, and uniquely styled. It's from the same folks who, in the 2000s, finally showed that BMW could be matched in the whole sport sedan/coupe game. Oh, and it has 400 horsepower. Four-hundred! With a four. And yet the 2017 Infiniti Q60 underwhelms. What looks so good on paper instead is rather conflicted, stuck somewhere in no-man's land between the traditional expectations of a performance sport coupe and those of comfier, more luxurious cruisers that isolate and pamper their occupants. It's a serious effort with serious engineering and a clear desire to be innovative, but at least in the range-topping Red Sport model we tested, it fails to come together in a way that truly excites or indulges. A great coupe should do one or the other, and ideally both. To explain, let's start under the hood, where Infiniti's all-new "VR" series 3.0-liter twin-turbo V6 makes its second appearance after debuting in the Q60's four-door sibling, the Q50. In the Q60 Silver Sport model, it produces 300 horsepower and 295 pound-feet of torque courtesy a pair of turbochargers that create 8.7 psi of boost. In the Red Sport, the knob is turned up to 14.7 psi, resulting in the oh-so-salivatory magic number of 400 hp along with 350 lb-ft of torque. A device known as an optical turbo speed sensor, special to the Red Sport, manages and maintains that extra boost, while an electric motor fitted to the valve timing system serves to quell any loss in throttle response due to forced induction. The Red also gets a second water-cooled intercooler, which, in both models, is distinctive for its more compact size, shorter airflow path, and, according to Infiniti, a resulting reduction in turbo lag and more immediate engine response. It's certainly a clear improvement on the somewhat rough 3.7-liter "VQ" V6 it replaces, which increasingly felt and sounded a little out of place in a luxury car. The new VR30DDTT, as it's so eloquently named, is buttery smooth and indeed responsive, likely capable of convincing luxury-car owners used to naturally aspirated V6s that everything's business as usual. Honestly, its character is reminiscent of a silky Honda V6. In some respects, that's a great thing. In others, it's where the Q60 starts to fall flat.