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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

Cadillac could base its entry-level sedan on the Chevy Cruze [UPDATE]

UPDATE: Cadillac spokesperson Donny Nordlicht tells Autoblog , "The post speculating on a future Cadillac model derived from the Chevrolet Cruze is completely false." Premium automakers Mercedes-Benz and Audi have seen plenty of success with new small front-drive-based sedans. The CLA-Class had its best January ever this year, while Audi moved more of its new A3 in 2015 than its predecessor sold in 2005 through 2010 combined. The fact that Cadillac wants a piece of that pie is no surprise, then. There's a new rumor that GM's luxury brand could launch its own compact – possibly called CT2 – to battle the Germans. Cadillac, a brand that's pushed hard to rebuild its rear-drive reputation, could develop a new entry-level model based on the front-wheel-drive 2016 Chevrolet Cruze's D2XX platform. Go ahead and make your Cimarron jokes. Sources are telling GM Inside News that a Cadillac built on the Delta platform would ditch the Cruze's turbocharged 1.4-liter four-cylinder for a 1.5-liter turbo in base models. General Motors' well received 2.0-liter turbo four would serve in higher-end models. According to GMIN, the Delta-based Cadillac would likely command a $6,000 to $9,000 premium over the Cruze, so figure $23,000 to $26,000 on the low end to $30,000 to $33,000 for something at the top of the range. As much as we dislike the kind of badge engineering that brought us the Cavalier-based Cadillac Cimarron in the '80s, the company has done an admirable job of distinguishing vehicles on shared platforms lately. A Delta-platform Cadillac would at least have a good basis – the new Cruze is surprisingly comfy. That said, we question GM's rationale if this rumor is indeed true. Put simply, Cadillac needs another sedan like I need another student loan payment. The company has four sedans, three of which overlap two segments, and none of which are selling very well. That's not because they're bad, but because customers want crossovers, of which Caddy has but one – the new XT5. Spending the time and money to add a fifth sedan to the mix when the company desperately needs to flesh out its CUV range would be a tremendous mistake. As much as we hate to say it, if Cadillac really wants to add a small, entry-level car to its range, it'd better be a crossover. Related Video:

Some 2012-13 Chevy Volts may not have enough battery coolant

The 2012 and 2013 model year Chevrolet Volt extended-range plug-in vehicle may have a battery glitch caused by low coolant levels. No recall has been issued and General Motors is taking care of the issue at no cost to drivers. Some of the affected Volts may have lower-than-advisable coolant levels because of some pesky air pockets in the car's cooling circuit. When the coolant levels get too low, the charging system for the battery powering the car's onboard generator (i.e. the Rechargeable Energy Storage System, or the RESS) may be shut down, turning one's Volt into a run-of-the-mill gas-powered car, and a pricey one at that. The Car Connection says GM is advising owners of the '12 and '13 Volts to contact their local Chevy dealer for a free fix. GM representatives didn't immediately respond to a request for comment from AutoblogGreen for more details. We believe this is a separate issue than the one that brought 8,000 Volts back to the dealers for a battery coolant fix, what GM called a "voluntary customer satisfaction effort," a few years ago. General Motors sold 23,094 Chevy Volts last year after selling 23,461 Volts in 2012, so that fix-it list may get fairly lengthy. Check out a GM-Volt.com user thread related to this issue here. *UPDATE: Chevrolet spokesman Randy Fox confirmed in an e-mail to AutoblogGreen that the company issued a service bulletin to dealers that they may need to top off coolant levels on certain Volts because of the issue, and that the vehicle will "return to normal charging operation" once that's done.