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New details emerge on Inifiniti QX50’s unique new variable-compression engine

Infiniti will release the world's first production variable-compression engine when it releases the 2019 QX50 midsize SUV sometime next year. Now we have some new details on the innovative new engine, which Infiniti is calling VC-T, for Variable Compression Turbo, after the luxury brand offered a prototype test drive. We wrote extensively about the complicated technology underpinning the new engine last year. It's the latest novel development that could represent a range-extender, if you will, for the embattled internal combustion engine in an era when automakers and governments are shifting their focus to electric vehicles. The VC-T is a new inline-four, 2.0-liter that combines the power of a high-performance turbo gasoline engine with the torque and efficiency of an advanced diesel engine, but without the latter's notorious emissions. It features the ability to seamlessly raise or lower the stroke of the pistons in the combustion chamber, depending on the driving conditions it detects and inputs from the driver, to select the best compression ratio—anywhere between 8:1, typical for high-performance engines, and 14:1 for high efficiency. In essence, it delivers the performance of a V6 but is much more efficient, with improved fuel efficiency of between 10 to 15 percent with its best competitors, per Car and Driver. You can view how it works in motion via the video below. This content is hosted by a third party. To view it, please update your privacy preferences. Manage Settings. It's also quieter, more lightweight and compact than V6 engines with comparable power outputs, estimated at 268 horsepower and 288 pound-feet of torque. In a prototype test drive, Car and Driver writes that the engine "felt very conventional" and responsive, with strong and smooth acceleration. "The only indication you have that the compression ratio is changing is from an indicator in the instrument cluster next to the boost gauge." The engine is expected to deliver fuel economy gains of 27 percent in combined city-highway EPA rating over the outgoing QX50, which had a 3.7-liter V6. The 2019 model, fitted with the VC-T, should get about 26 mpg in combined fuel economy, and it will get to 60 mph almost one second faster than its four-cylinder counterparts, Nissan's chief powertrain engineer, Shinichi Kiga, told Automotive News. The VC-T engine is the result of 20 years of development spanning more than 100 prototypes and around 300 patents at Nissan.

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.

2015 Spanish F1 Grand Prix makes its Deutsche mark

The first race of the European Formula One season inaugurates the second phase of the Championship. Teams overhaul their cars with the big updates they've been working on since Australia, and at the end of The Battle of Spain we find out how the positions on the field have changed. Mercedes-AMG Petronas driver Nico Rosberg brought a big update to his psychology, straight-up beating teammate Lewis Hamilton to take his first pole position of the season. Mercedes owns the front row and Ferrari maintains its status as primary challenger, Sebastian Vettel lining up in third. Williams proved it's been hitting the books to do better in class, though, Valtteri Bottas slotting into fourth. And Toro Rosso's visit to a track that rewards strong aero rewarded them with the best team grid position since the Italian Grand Prix in 2008: Carlos Sainz secured fifth, ahead of Max Verstappen in sixth. Kimi Raikkonen's bout of Saturday woes – it seems the Finn is always handicapped by lots of tiny issues – continued in Barcelona with one of his sets of prime tires getting cooked by malfunctioning tire warmers. He recovered well enough to take seventh on the grid, but he's got some strong competition ahead of him. He led three other drivers in the Continuous Issues department, Daniil Kvyat unable to wrestle his Infiniti Red Bull Racing higher than eighth, Williams driver Felipe Massa getting it wrong in Turn 3 to fall five places behind his teammate Bottas, and Daniel Ricciardo in the second Red Bull enduring another engine change and sloppy car behavior to get tenth. And while it turned out to be a steady race a little rough around the edges, the positions on the battlefield just might have changed. A little. Of the 66 laps in the race we might have seen Rosberg for three of them – maybe. The German got a smashing start, had a clear lead into Turn 1, and after that we checked in occasionally during his two pit stops and again at the checkered flag. He owned the entire weekend the way we're used to seeing his teammate do, and the cameras left him alone to run his race. No one got within seven seconds of him during the first third, and as the pit stop strategies played out that cushion grew. He finished seventeen seconds ahead of Hamilton, and 45 seconds ahead of third-placed Vettel. Hamilton, on the back foot all three days, stumbled out of the gate.