2012 Nissan Sentra Base Sedan 4-door 2.0l 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.

NHTSA probes Nissan Versa for potential pedal problem

The National Highway Traffic Safety Administration is commissioning an engineering analysis to investigate a possible problem with the 2013-2015 Nissan Versa and 2014-2015 Versa Note. The agency wants to gather more information about sections of the footwell that can potentially interfere with operating the pedals, and NHTSA estimates this could affect 360,000 vehicles if the agency requests a recall. The preliminary evaluation of this problem was opened last June when NHTSA received a report of a driver's foot being trapped by a trim panel on the right side of the footwell. Since then, the government agency has tallied 24 total complaints, including one crash and an injury, which might have been linked to this issue. It's also possible the HVAC relay actuator in a nearby area could be doing the same thing. Either might lead to unintended acceleration and delayed braking. NHTSA's new engineering analysis is meant to "assess the scope, frequency and safety-related consequences of the alleged defect." It also adds the 2015 Versa Sedan and Note to the list of potentially affected models but removes the examples from 2012 because of a different footwell panel design. "Nissan is cooperating fully to answer the agency's questions," the automaker said in a prepared statement emailed to Autoblog (embedded in full below). You can read the entire report in PDF format, including photos of the potential issue, here. INVESTIGATION Subject : Pedal Operation Interference Date Investigation Opened: APR 01, 2015 Date Investigation Closed: Open NHTSA Action Number: EA15003 Component(s): SERVICE BRAKES, HYDRAULIC , VEHICLE SPEED CONTROL All Products Associated with this Investigation Vehicle Make Mode lModel Year(s) NISSAN VERSA 2013-2015 NISSAN VERSA NOTE 2014-2015 Details Manufacturer: Nissan North America, Inc. SUMMARY: On June 24, 2014, the Office of Defects Investigation (ODI) opened PE14-018 to investigate allegations that the tunnel carpet cover trim panel on model year (MY) 2012 through 2014 Nissan Versa, Versa Sedan and Versa Note vehicles has, in certain situations, interfered with the driver's ability to promptly release the accelerator pedal and transition to the brake pedal. This may result in delayed brake application or brief incidents of unwanted acceleration.

Nissan ZEOD RC on track and from behind the wheel

The Nissan ZEOD RC hybrid racecar has had mixed success in its competition life. It was invented to do a completely electric, high-speed lap at the 24 Hours of Le Mans, which it was able to do in practice. However, when the big event actually came, the car lasted less than an hour before it had to bow out with transmission issues. Nissan hasn't completely given up on its experiment, though. The experience (and possibly some of the tech) is going to help with the GT-R LM racer next year, and now the ZEOD is getting its chance to see how it handles the Top Gear test track.
Unfortunately, it's not The Stig piloting the ZEOD; instead, the magazine's motoring editor Ollie Marriage is the lucky man for the job. The car's sharp shape seems to be a good metaphor for how it handles because it just seems to dart around the track. Its tiny, turbocharged 1.5-liter engine with 400 horsepower and two electric motors put out a claimed 750 horsepower, and that seems like plenty for the relatively short Top Gear course.
As usual of Top Gear, the cinematography here is fantastic, and a second video shows off a single lap of the course from around the car. It's amazing to watch, especially with its big screen constantly showing the camera view out of the rear. Scroll down to see both.