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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’s move to Woodward is the right one — for the company and for Detroit

Back in 2018, Chevy invited me to attend the Detroit Auto Show on the company dime to get an early preview of the then-newly redesigned Silverado. The trip involved a stay at the Renaissance Center — just a quick People Mover ride from the show. IÂ’d been visiting Detroit in January for nearly a decade, and not once had I set foot inside General MotorsÂ’ glass-sided headquarters. I was intrigued, to say the least. Thinking back on my time in the buildings that GM will leave behind when it departs for the new Hudson's site on Woodward Avenue, two things struck me. For one, its hotel rooms are cold in January. Sure, itÂ’s glass towers designed in the 1960s and '70s; I calibrated my expectations accordingly. But when I could only barely see out of the place for all the ice forming on the inside of the glass, it drove home just how flawed this iconic structure is.  My second and more pertinent observation was that the RenCen doesnÂ’t really feel like itÂ’s in a city at all, much less one as populous as Detroit. The complex is effectively severed from its surroundings by swirling ribbons of both river and asphalt. To the west sits the Windsor tunnel entrance; to the east, parking lots for nearly as far as the eye can see. To its north is the massive Jefferson Avenue and to its south, the Detroit River. You get the sense that if Henry Ford II and his team of investors had gotten their way, the whole thing would have been built offshore with the swirling channel doubling as a moat. This isnÂ’t a building the draws the city in; itÂ’s one designed to keep it out. Frost on the inside of the RenCen hotel glass. Contrasted with the new Hudson's project GM intends to move into, a mixed-use anchor with residential, office, retail and entertainment offerings smack-dab in Detroit's most vibrant district, the RenCen is a symbol of an era when each office in DetroitÂ’s downtown was an island in a rising sea of dilapidation. Back then, those who fortified against the rapid erosion of DetroitÂ’s urban bedrock stood the best chance of surviving. This was the era that brought us ugly skyways and eventually the People Mover — anything to help suburban commuters keep their metaphorical feet dry. The RenCen offered — and still offers — virtually any necessity and plenty of nice-to-haves, all accessible without ever venturing outside, especially in the winter, but those enticements are geared to those who trek in from suburbia to toil in its hallways.

GM faces possible class action lawsuit over 8-speed transmission

General Motors has been hit with a class-action lawsuit from owners who allege the eight-speed automatic transmission found in several rear-wheel-drive Chevrolet, Cadillac and GMC models between the 2015 and 2019 model years has a defect that causes the vehicles to hesitate and jerk when accelerating or slowing down. The lawsuit was posted to ClassAction.org and spotted by GM Authority. Problems with GM's Hydra-Matic 8L90 and 8L45 transmissions have been well-documented on Internet forums and via complaints filed with the National Highway Traffic Safety Administration, with many reporting damage to their vehicles. The lawsuit was first filed in December in U.S. District Court for the Southern District of Florida but appears to have been transferred recently to New York. Autoblog sought comment from Theodore Leopold, the lead attorney for the plaintiffs. "These transmissions have a common defect," the complaint reads. "Drivers attempting to accelerate or decelerate their cars feel a hesitation, followed by a significant shake, shudder, jerk, clunk, or 'hard shift' when the vehicle's automatic transmission changes gears." The problem also occurs when the vehicles accelerate in a single gear, without shifting, the plaintiffs allege. "Drivers have reported that the shift is sometimes so violent, they feel as though they have been hit by another vehicle." The problem is believed to center on the transmission, torque converter or both. The complaint says it causes undue friction, causing hydraulic systems and gears to function improperly and sometimes leaves metal shavings throughout the transmission, leading to costly repairs and replacement of parts or the entire transmission. It says GM has known about the problems since shortly after it introduced the transmissions, and has issued 13 technical service bulletins, none of which have resolved the problem. GM declined to comment on the lawsuit. The plaintiffs say GM should have warned consumers about the issues and covered repairs under each vehicle's three-year/36,000-mile bumper-to-bumper warranty. They're seeking statewide classes in at least six states: California, Florida, Illinois, New York, Oklahoma and Texas.