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GM patent reveals new two-stage turbocharger

Modern turbochargers may be some of the best ever made, but performance is something that engineers are always trying to improve. According to GM Inside News, General Motors (GM) is hoping to alleviate some of the negative aspects of a two-stage turbocharger setup with a newly-patented design. The patent, that was filed on May 19, 2016, reveals a clever bypass system that allows the engine, a four-cylinder unit, to optimize both the low-pressure and high-pressure inlets for its respective functions. According to the filing, a conventional two-stage turbocharger setup is engineered to allow both turbines to operate simultaneously at low and mid engine speeds. At high engine speeds, only the low-pressure turbine works. The setup can't isolate either the low or high pressure side, which can impair low-end performance. GM's new two-stage turbocharger setup looks to eliminate this by linking the high-pressure turbo to the exhaust manifold through the high-pressure inlet duct. The low-pressure turbo is attached to the high-pressure turbo by a low-pressure inlet duct, which is linked to a connecting channel. A single actuator that is housed in the exhaust manifold creates a bypass that can opens the high-pressure inlet or close the connecting channel. Depending on what the engine load and speed is, the ECU guides the actuator—a single rotating spindle with discs corresponding to flanges on the high and low pressure sides—to isolate one of the two turbos. Isolating the turbos allow the respective inlets to be engineered for the best possible fluid dynamic performance. The setup should increase performance and decrease lag. There's no word on what car this setup will make an appearance on, but it will most likely be used in premium vehicles before trickling down to the rest of GM's vehicles. Related Video: News Source: GM Inside News, AutoGuide via GM Authority Cadillac Chevrolet GM Technology Sedan turbo patent engine turbocharging

Consumer Reports criticizes small turbo engines for misleading performance, fuel economy claims [w/video]

Consumer Reports has taken aim at at small-displacement, forced-induction engines, saying the powerplants don't manage to deliver on automaker fuel economy claims. Manufacturers have long held that smaller, turbocharged engines pack all power of their larger displacement cousins with significantly better fuel economy, but the research organization says that despite scoring high EPA economy numbers, the engines are no better than conventional drivetrains in both categories. Jake Fisher, director of automotive testing for Consumer Reports, says the forced induction options "are often slower and less fuel efficient than larger four and six-cylinder engines."
Specifically, CR calls out the new Ford Fusion equipped with the automaker's Ecoboost 1.6-liter four-cylinder engine. The institute's researchers found the engine, which is a $795 option over the base 2.5-liter four-cylinder, fails to match competitors in acceleration and served up 25 miles per gallon in testing, putting the sedan dead last among other midsize options.
The Chevrolet Cruze, Hyundai Sonata Turbo and Ford Escape 2.0T all got dinged for the same troubles, though Consumer Reports has found the turbo 2.0-liter four-cylinder in the BMW 328i does deliver on its promises. You can check out the full press release below. You can also read the full study on the Consumer Reports site, or scroll down for a short video recap.

Chevy Silverado Midnight Edition, Custom ready to stand out in pickup line

Chevrolet spent its Chicago Auto Show introducing a pair of fullsize pickups that promise image-conscious buyers a truck experience that goes beyond the standard range, with the murdered-out Midnight Edition and the um, not murdered-out, Custom. Let's start with the Custom, which adds 20-inch alloys, as well as chrome bumpers, mirror caps and door handles to the Silverado LS. Available in both V6 and V8 varieties, and with the customer's choice of two- or four-wheel drive, the Silverado Custom is the decidedly mellower example of Chevy's special edition styling. The Midnight Edition, meanwhile, throws subtlety out the window with a menacing set of visual upgrades. Based on the Z71, the Midnight adds 18-inch wheels, a spray-in bedliner and unique Z71 and Bowtie badges, all in black, of course. The front and rear bumpers, headlamp bezels, tow hooks, mirror caps and door handles, are also finished in the stealthy shade. Check out our live images of both special edition trucks, and let us know what you think down in Comments.