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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

Chevy Colorado, GMC Canyon get updated tachometers due to graphical error

After James Bearing bought a Chevrolet Colorado, he noticed a discrepancy between the truck's spec sheet and the truck's tachometer: Chevrolet said 3.6-liter V6 in the little pickup produces 305 horsepower at 6,800 rpm, but the the tachometer indicates a redline at 6,500 rpm. So either he wasn't making as much power as he was promised, or the tachometer display was incorrect. Bearing said he asked Chevy about it but got no response. Until now. A General Motors spokesman said the rev limiter is indeed set for 6,800 rpm, but the tach graphics "are slightly off" in the Colorado and the GMC Canyon, and submitted an SAE horsepower certification to back him up. If you're wondering how such a thing got past quality control... well, let's just say you're not alone. GM is going to fix "the graphics on future trucks," which makes it sound like Bearing will just have to learn to live with the indicated redline he's got. He could always pretend he's driving a sleeper, with four more ponies waiting to be unlocked in the danger zone for those who dare. Related Video: Featured Gallery 2015 Chevrolet Colorado: First Drive View 38 Photos Related Gallery 2015 GMC Canyon: Quick Spin View 27 Photos News Source: Auto Guide Auto News Chevrolet GM GMC Truck gmc canyon

Nissan Leaf, Chevy Volt have best sales month of 2015

Things are trending upwards for the two best-selling plug-in vehicles in the US. Both the Chevy Volt and the Nissan Leaf had their best sales month of 2015 in May, with the Volt selling 1,618 units and the Leaf moving 2,104. The upward swings come at an interesting time, with lots of excess first-gen Volts waiting for buyers and some buyers already ordering their second-gen Volts. So far in 2015, the Leaf has outsold the Volt 7,742 to 4,397. While 7,700 Leafs is respectable, it's nowhere near the numbers that Nissan will have to hit to reach the 50,000 annual sales that CEO Carlos Ghosn says is possible in the US. Still, the Leaf had its best sales month since December 2014 (when it sold 3,102 units) in May, but last month was still down 32.5 percent compared to May 2014. Despite the smaller overall number, May represents a big positive for Chevy, which has seen sluggish sales for the Volt for a long while now. The 1,618 Volts sold last month are only 3.9 percent lower than the 1,684 sold in May 2014 and May 2015 was the best month for Volt sales since August 2014. Perhaps salesmen are ready to make deals, what with thousands sitting around on dealer lots right now. The next-gen Volt is due this fall, and the order books (in California, at least) opened up this week. Like every month, our full wrap-up of green car sales in the US is coming soon (the VW e-Golf, for example, hit a best-ever high of 410 sales). Until then, feel free to discuss the Volt and Leaf sales figures in the Comments. Green Chevrolet Nissan Electric Hybrid ev sales hybrid sales