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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

Weekly Recap: Car-pedestrian crashes remained elevated in 2014

The death of American Horror Story: Freak Show star Ben Woolf served as a reminder this week that car crashes involving pedestrians remain a problem, and a new study issued on Thursday reinforced that the situation isn't really getting better. The Governors Highway Safety Association found a slight decline, 2.8 percent, in the number of pedestrian deaths in the first six months of 2014. Fatalities dropped from 2,141 to 2,125 compared with the same period in 2013, though the association says it's a statistical wash when factoring in undercounting. Deaths are still 15-percent higher than in 2009. "The number of deaths remains relatively high and is cause for concern," wrote Allan Williams, who compiled the report and is the former chief scientist at the Insurance Institute for Highway Safety. This is the first look at data from last year, and the National Highway Traffic Safety Administration will issue its full-year results later. The GHSA found some progress on the roadways, as 24 states and the District of Columbia reported drops in pedestrian deaths. In some states, the problem isn't even a problem at all: Nebraska and Wyoming reported one fatality apiece, though large population centers in urban areas are where most accidents occur. "This is a clearly a good news, bad news scenario," Jonathan Adkins, GHSA executive director, said in a statement. "While we're encouraged that pedestrian fatalities haven't increased over the past two years, progress has been slow." Other News & Notes Cadillac previews CT6 during Oscars Cadillac previewed its upcoming flagship sedan, the CT6, in commercials that aired Sunday during the Oscars. As expected, the creased sedan carries on Cadillac's recent design language, and the car in the commercial looks like a larger version of the CTS and ATS sedans. The CT6 will be revealed this spring at the New York Auto Show and launch late this year. It will be assembled at General Motors' Detroit-Hamtramck factory on a rear-wheel-drive chassis, and the CT6 is the first car to use Cadillac's revised alpha-numeric naming scheme. The commercials also kicked off Cadillac's "Dare Greatly" campaign, which is the first with its new advertising agency, Publicis Worldwide. Honda unexpectedly changes CEOs Honda unexpectedly announced this week that it will change CEOs. Current chief Takanobu Ito will step down in June and be replaced by company veteran Takahiro Hachigo.

GM recalling another 2.7 million vehicles in five separate campaigns

The recalls keep rolling in from General Motors, evidently keen to avoid repeating the mistakes of the ignition-switch debacle and clean house. This time they're all coming at once, with five separate recalls announced together covering approximately 2.7 million vehicles.
The largest of the five actions involves over 2.4 million units of the previous-generation Chevrolet Malibu and Malibu Maxx, Pontiac G6 and Saturn Aura in order to fix brake light wiring harness, which have been found to be susceptible to corrosion. The recall is separate from the 56k Aura sedans which GM recently recalled over faulty shift cables, not to mention the previous massive recall of 1.3 million vehicles - some of them the same models - but appears to have resulted from the National Highway Traffic Safety Administration investigation that started with the G6 almost a year ago.
The second-largest campaign involves the 2014 Chevy Malibu, specifically those fitted with GM's 2.5-liter engine and stop/start system, approximately 140,000 examples of which has been found to have problematic brakes. The issue does not appear to be connected to the recall of 8k Malibu and Buick LaCrosse sedans (also involving brake woes) which we reported upon last week. Four crashes have been reported in such models, but GM admits it's not yet clear if the problem was a contributing factor in the accidents.