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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

Nissan Leaf has 2nd-best sales month ever, Chevy Volt does a 2013 repeat [UPDATE]

UPDATE: The official press release says that "Volt [sales were] up 7 percent," but Randy Fox let AutoblogGreen know that this is simply due to a change in the fleet/retail mix between March 2013 and 2014. The actual number sold was exactly the same in the two months. A month ago, Nissan's director of EV sales and marketing, Toby Perry, said he expected to see the Leaf's sales momentum continue into March. It wasn't a big leap, since January and February were slow sales months in 2013 (around 640 each) before a big climb to 2,200 in March. In 2014, the first two months of the year were better (around 1,300 each) but Nissan can still be happy that the Leaf just had the best March ever and its second-highest sales month ever, with 2,507 sold. That's a 12.1 percent increase from 2013 and Perry said in a statement to AutoblogGreen that one reason is all of the buyers who are becoming evangelists for the vehicle. "We've also seen an increase in showroom traffic as we enhanced our marketing presence in March," he said. Nissan pointed to cities like Washington, DC, Raleigh-Durham, NC and urban areas in Texas as strong Leaf markets last month. On the Chevy Volt front, January and February were also slow months in 2014, down roughly half from the 2,000-ish the plug-in hybrid was selling at the end of 2013. For 2014, sales were up slightly from the first two months of the year and Chevy spokesman Randy Fox told AutoblogGreen that the March number was "pretty flat, year-over-year." Even with that warning, we were surprised to see the total come in at 1,478. Why's that? Because the total for March 2013 was ... 1,478. So, yeah, that's pretty steady even if there were 26 selling days in March period this year compared to 27 last year. As always, our more complete report of last month's green car sales will be coming soon. News Source: General Motors, Nissan Green Chevrolet GM Nissan Electric Hybrid PHEV ev sales

2016 Chevy Volt will not need premium gas

Buried in the new technical details of the 2016 Chevy Volt released yesterday was a throwaway line about a small but important change that's due to the new 1.5-liter, four-cylinder engine. The first-gen Volt has always required premium gas but the new powerplant will be happy burning plain old regular. The Volt's chief engineer, Andrew Farah, told AutoblogGreen that the change was due to today's Volt owners explaining they were not happy paying for top-shelf petroleum. "The ability to use regular unleaded was based directly on customer feedback," he said. "Since the range extender is an all-new engine, it was optimized to use regular unleaded at the outset. Using regular fuel will not have effect on vehicle acceleration or other performance factors." As Larry Nitz, GM's executive director of vehicle electrification, told AutoblogGreen yesterday, the new engine is more powerful and quieter than the outgoing 1.4-liter engine that's used in the current Volt. Fuel economy and EV range specs for the next-gen Volt are not expected until the full car is revealed at the Detroit Auto Show in January.