2009 Infiniti G37x on 2040-cars

Auto blog

Infiniti's variable compression engine in the 2019 QX50 is the first of its kind

The world's first variable compression ratio engine is here, in a production car. That car is the 2019 Infiniti QX50, debuting this week at the Los Angeles Auto Show. The midsize crossover has seen a refresh that has brought it an all-new platform together with new driver assist features, but it's the engine that's the centerpiece here. Nearly everything is continuously variable under the hood of the QX50 – not only the new shift-by-wire XTRONIC CVT. The new VC-Turbo gasoline engine is able to change its compression ratio from 8:1 to 14:1, or anything in between depending of the driving situation; whether there is need for top-end power or turbodiesel-like torque from low revs, or optimized fuel economy. The pistons' reach is continuously adjusted by an electric "Harmonic Drive" motor, which controls a multi-link system, affecting the top-dead-center of the pistons and changing the compression. The engine can also switch between efficiency-maximizing Atkinson cycle and regular combustion cycle, on the go – and there's both multipoint injection and gasoline direct injection employed. The result is 268 horsepower at 5,600 rpm and 280 pound-feet of torque at 4,400 rpm; good figures for a 2.0-liter four-cylinder gasoline engine with a single-scroll turbocharger. Infiniti says that the FWD version's fuel economy of 27 miles per gallon combined is 35-percent better than the previous-generation V6 engine; in AWD guise, it reaches 26 mpg, which is a 30-percent improvement. The new engine is pretty much all-aluminum, but the vaguely magical-sounding "transformative multi-link components" behind the variable compression system are made from high-carbon steel alloy. The engine's multi-link system also enables it to do away with any balancing shafts, and Infiniti compares its smoothness to a V6 rather than a regular four-cylinder. In addition to the aforementioned tech, the VC-Turbo engine has the world's first active engine mount vibration damping system to smoothen its operation even further. Related Video:

Nissan recalling GT-R, Infiniti crossovers over steering column issue

Nissan has discovered a problem with the steering column on some of its higher-end all-wheel-drive vehicles from a few years back, and has issued a recall in conjunction with the National Highway Traffic Safety Administration to address the issue. The issue revolves around the outer tube on the steering column, which may not be perfectly round. That would put extra stress on the upper steering bearing, which could cause it to fracture, disabling the car's steering ability and potentially leading to a crash. The problem affects Nissan's flagship GT-R supercar – specifically 2009 models manufactured between March 14, 2007, and April 25, 2008) as well as an array of Infiniti crossovers: namely the 2008 EX35 and the 2008-09 FX35 and FX45. In the case of the luxury crossovers, Infiniti dealers are being instructed to replace just the steering shaft, but Nissan dealers will have to replace the entire steering column assembly on the GT-R. All told, the recall is estimated to encompass 16,973 vehicles across the United States. RECALL Subject : Steering Column Tube may be Out of Round Report Receipt Date: FEB 02, 2015 NHTSA Campaign Number: 15V054000 Component(s): STEERING Potential Number of Units Affected: 16,973 Manufacturer: Nissan North America, Inc. SUMMARY: Nissan North America, Inc. (Nissan) is recalling certain model year 2008 Infiniti EX35 vehicles manufactured June 29, 2007, to April 25, 2008, 2009 Infiniti FX35 and FX45 vehicles manufactured October 31, 2007, to April 16, 2008, and 2009 Nissan GT-R vehicles manufactured March 14, 2007, to April 25, 2008. The steering column outer tube may not be round, resulting in extra stress being applied to the upper steering bearing. This stress may cause the bearing retainer to fracture, creating extra play in the steering wheel or a possible loss of steering. CONSEQUENCE: Extra play in the steering wheel or a loss of steering may increase the risk of a crash. REMEDY: Nissan will notify owners, and dealers will replace the steering shaft on the Infiniti EX35, FX35, and FX45 vehicles, and will replace the steering column assembly on the Nissan GT-R vehicles, free of charge. The manufacturer has not yet provided a notification schedule. Infiniti owners may contact customer service at 1-800-662-6200. Nissan owners may contact the GT-R hotline at 1-866-668-1487.

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.