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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.

Nissan Leaf is now the best-selling plug-in vehicle of all time in US

Numbers don't lie. And in some instances, you can see their truth from miles away. As everyone expected, the Nissan Leaf is now officially the best-selling plug-in vehicle in the US. While the two vehicles aren't direct competitors (one's a pure EV and the other is a plug-in hybrid), they certainly dominate the plug-in vehicle sales charts. When we do a little math on those charts, we see that since the two vehicles went on sale at the end of 2010, the Volt has sold 75,231 units while the Leaf is now at 76,407, giving the Leaf a 1,176-vehicle lead. The Leaf trailed the Volt by just two units at the end of February. This is the first time the EV had held the overall lead since the end of February 2012, when it was ahead 10,847 to 9,623 and for a while there at the end of 2013, the Volt was up by around 12,000 units. Times have changed, though, and we don't expect the lead to switch back until the next-gen Volt goes on sale later this year, and even then nothing is certain. The Leaf sold 1,817 copies last month, a drop of 27.5 percent from last year. Year-to-date, the Leaf has sold 4,085 units, down 21.2 percent from the same time period in 2014. There were 639 Volts sold last month, a 56.8-percent sales decrease compared to March 2014. So far this year, Volt sales are down 48 percent. Green Chevrolet Nissan ev sales hybrid sales