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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

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.

GM recalls 638,000 U.S. SUVs, trucks for unintended braking

WASHINGTON — General Motors is recalling 638,000 U.S. sport utility vehicles and pickup trucks because a wheel-speed sensor could fail and cause unintended braking, it said Thursday. The recall covers 2015-2020 Chevrolet Suburban, Tahoe, and Yukon and 2014-2018 Chevrolet Silverado 1500 and GMC Sierra 1500 vehicles equipped with a 5.3-liter engine, a 3.08-ratio rear axle and four-wheel drive. The sensor failure could result in unintended activation of the driveline protection system, and cause unintended braking of the wheel on the opposite side of the failed sensor. That could cause the vehicle to pull to one side unexpectedly, increasing the risk of a crash, the Detroit automaker said. GM said it was not aware of any crashes relating to the issue but found 150 field claims alleging the condition caused unintended braking or lateral vehicle motion. A GM dealer in May submitted a warranty report relating to the issue in a 2018 GMC Yukon, and two days later, a GM brand quality manager submitted the report to GMÂ’s Speak Up For Safety program that tracks potential safety issues, which prompted a GM investigation and testing. Recalls Chevrolet GM GMC Truck SUV