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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

Looking back at the Citation IV concept that likely shaped the GM EV1

Those who forget history are condemned to repeat it. We're not sure how that applies to the GM EV1, but we'd still like to share something from Autoline Daily, an online automotive new show with our friend John McElroy. He's been covering the business for decades now and recently found something interesting: pictures of the 1984 Chevrolet Citation IV concept, seen above. Displayed half a decade before the first electric concept that would become the EV1 (inset), McElroy says it's now clear that the elegant, aerodynamic EV1 took a lot of styling cues from the Citation IV, which was developed in part thanks to GM's new-at-the-time Aerodynamics Laboratory. We agree with him that the spats over the rear wheels, the flush glass, and the covered headlights all bear a certain kind of similarity between the two cars. That the colors almost match is a nice coincidence. The Impact (the concept version of the EV1) looked "frumpier," McElroy says, because it wasn't as long as the Citation. You can read a lot more about the Citation IV here and check out McElroy's thoughts in the video below. Find the Citation starting at around 3:45. This content is hosted by a third party. To view it, please update your privacy preferences. Manage Settings.

GM re-recalls 11k SUVs

General Motors is recalling a bunch of previously recalled SUVs because, well, they still aren't quite fixed. The latest repairs are necessary on 10,974 SUVs in North America, including 9,932 in only the US. Affected models include the 2006-2007 Buick Rainier, Chevrolet Trailblazer, and GMC Envoy; plus the 2006 Trailblazer EXT and Envoy XL. While not listed by NHTSA, a statement by GM to Autoblog says the 2006-2007 Saab 9-7X and Isuzu Ascender are also affected. In these SUVs, it's possible that liquid could get into the driver's door master power window switch module and cause a short circuit. This could potentially lead to a fire, and owners are urged to park the vehicles outside until repaired. GM has been trying to fix this issue for years. It started as an investigation into fires, and that led to a recall for about 250,000 vehicles in cold-weather states. A nationwide campaign came in 2013 for 193,000 of them in the US. Last year, the automaker decided to replace the whole module as a repair. However in a recent investigation of these recalls, GM discovered that this latest group of SUVs never received the new part. According to documents submitted to NHTSA (as a PDF), "Some dealers incorrectly used the labor code associated with module replacement when, instead of replacing the module, they only added a protective coating to the module." To fix things this time, the models finally get the correct component. Related Video: GM Statement General Motors is recalling 9,932 older midsize SUVs in the U.S. because they were mistakenly excluded from an earlier recall. Certain 2006 Chevrolet TrailBlazer EXT and GMC Envoy XL, and 2006-2007 TrailBlazer, Envoy, Buick Rainier, Saab 9-7X and Isuzu Ascender vehicles may continue to have a condition in which the printed circuit board inside the driver's door may corrode and short if exposed to certain fluids such as melted snow containing road salt. GM is aware of four fires but no crashes, injuries or fatalities associated with the expanded recall. The total number of vehicles being recalled, including Canada, Mexico and exports is 10.974. Customers are urged to park these vehicles outside until repairs have been made. GM reported this recall to the NHTSA on September 23.