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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.

GM dealers unhappy about pickup prices

The backlash is beginning. Following General Motors' price hike of the Chevrolet Silverado and GMC Sierra last week, dealers across the country are expressing their ire over increasing prices in the face of rebates and discounts on trucks from Ford and Ram.
Speaking to Automotive News, Sam Pilato, the general manager at Dimmitt Chevrolet in Clearwater, FL, Silverados are "selling very poorly." W. Carrol Smith, the president of Monument Chevrolet in the heart of truck country, Texas, said, "[GM's] position is that the vehicle stands on its own and it doesn't need a bigger rebate. That's not what the market is telling us."
According to AN, that's the general attitude amongst Chevy and GMC dealers across the country, where the twin pickups are getting butchered in sales by competitors offering up to $9,000 off their sticker prices. Part of the problem for GM is that its trucks are arriving on the market near the end of the current F-150's lifecycle, a fact that Ford has taken advantage of.