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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

Cadillac ATS was almost front-wheel drive

"We were going to do a front-wheel drive Cadillac compact off of Delta because it was going to be less expensive," Doug Parks, General Motors' vice president of global product programs, told the Automotive News during the Detroit Auto Show in January of this year. That sentence, referring to early ATS discussions more than five years ago - a period when the automaker, and the industry, was struggling - reveals that Cadillac's highly acclaimed rear-wheel drive compact sedan almost never happened.
Parks revealed that that automaker actually built a 2.0-liter test mule, on GM's Delta platform (shared with the Chevrolet Cruze and Buick Verano) and tested it in Europe. While the prototype was "pretty darn good," according to Parks, the team realized that in order to compete against Mercedes-Benz and BMW it would have to invest in a new rear-wheel drive platform.
The resulting all-new Alpha platform would eventually underpin the Cadillac ATS, and many would argue that its balanced rear-wheel drive chassis is its single most important attribute. Thankfully, the Alpha's goodness won't stop with the ATS. The upcoming 2014 Cadillac CTS and the future Camaro will also share its architecture, meaning the Cimarron will remain a distant memory.

Cadillac ELR update delayed over autonomous drive systems issues

Rumors had been circulating that the 2016 Cadillac ELR would bow in Los Angeles recently, featuring, in Cadillac's own words, "engineering enhancements." The rumors and that quote are as far as it got – the updated ELR pulled a no-show in LA, and no one outside of the brand appears to know when it will appear. GM Inside News says its sources at Cadillac pinned the ELR's absence on some autonomous driving features not being ready to reveal. According to GMI, Cadillac insiders say the upgraded ELR will be a "highly autonomous vehicle," and the company needs more time to gets its systems polished. The site says "it's not unreasonable to assume that ELR will be [the] vehicle" that gets Cadillac's Super Cruise technology, but that seems a lot more involved than "engineering enhancements," and in September Cadillac said we'd see it sometime in the next two years. It's possible the wait for the 2016 ELR and its secrets might only be a couple of months: the next-generation Chevrolet Volt, which shares a platform with the ELR and whose engineering updates we know quite a bit about, is scheduled to appear at the 2015 Detroit Auto Show in January.