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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 execs fired over fraudulent India emissions testing

General Motors hadn't had a recall in India since 1995. That changed when it was discovered that certain employees were playing tricks with local emissions testing in order to ensure passing grades for engines. More than ten GM Powertrain employees in India and the US have been let go over the ensuing emissions flap, including Sam Winegarden, VP of global engine engineering, a man who has been with the company since 1969, leading development of some marquee powerplants.
According to Automotive News, an internal investigation revealed that employees "violated testing procedures," sometimes swapping specially prepared low-emissions engines during testing regimes for the Chevrolet Tavera SUV equipped with the 2.0-liter and 2.5-liter engines. Employees were also manipulating weights in order to get vehicles placed into different emissions categories. The discovery has led to GM recall the 114,000 Taveras produced over an eight-year period and halting their production and sale.
The Economic Times of India reports that the issue is due to "a faulty component." GM has developed a solution to the issue, and once it is validated in testing and approved by the Indian authorities, the recalled vehicles will be fixed at dealers and production will resume.

2020 Chevy Tahoe High Country spied along with next-gen Escalade

Have no fear, the big grilles are here. Or, at least we think they're coming. One of our spy shooters caught the next-gen Chevrolet Tahoe and Cadillac Escalade out testing with more of their fronts ends exposed than before. Starting with the Tahoe, we can see what amounts to a blinding amount of chrome under the wrappings. We're guessing this would be a new Tahoe High Country trim level, mirroring the range-topping trim level currently offered on the Silverado and Traverse. The Tahoe's current range topper is the Premier. Although the rather ornate details in the grille are not found on the current High Country trims, they also seem like something that would be available on the priciest Tahoe available. The same could be said of the LED lighting details visible under the camo as the Silverado High Country, shown below, does indeed have unique LED elements. The next-generation Cadillac Escalade only shows up in two of the photos. As we can't see shiny chrome reflecting through the camo, we're guessing the Escalade will adopt a blacked out grille similar those found on the XT6 and other Cadillacs. We can also see horizontal lighting elements similar to those on other recent Cadillacs. As this is an Escalade, however, we'd imagine everything will be supersized. GM will be ushering these trucks out soon, with the independent rear suspension being the big story. Besides the improved ride and handling, it should result in substantially improved cargo space and third-row legroom. Doing so would at least close the gap with the biggest Lincoln and Ford SUVs.