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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

A car writer's year in new vehicles [w/video]

Christmas is only a week away. The New Year is just around the corner. As 2014 draws to a close, I'm not the only one taking stock of the year that's we're almost shut of. Depending on who you are or what you do, the end of the year can bring to mind tax bills, school semesters or scheduling dental appointments. For me, for the last eight or nine years, at least a small part of this transitory time is occupied with recalling the cars I've driven over the preceding 12 months. Since I started writing about and reviewing cars in 2006, I've done an uneven job of tracking every vehicle I've been in, each year. Last year I made a resolution to be better about it, and the result is a spreadsheet with model names, dates, notes and some basic facts and figures. Armed with this basic data and a yen for year-end stories, I figured it would be interesting to parse the figures and quantify my year in cars in a way I'd never done before. The results are, well, they're a little bizarre, honestly. And I think they'll affect how I approach this gig in 2015. {C} My tally for the year is 68 cars, as of this writing. Before the calendar flips to 2015 it'll be as high as 73. Let me give you a tiny bit of background about how automotive journalists typically get cars to test. There are basically two pools of vehicles I drive on a regular basis: media fleet vehicles and those available on "first drive" programs. The latter group is pretty self-explanatory. Journalists are gathered in one location (sometimes local, sometimes far-flung) with a new model(s), there's usually a day of driving, then we report back to you with our impressions. Media fleet vehicles are different. These are distributed to publications and individual journalists far and wide, and the test period goes from a few days to a week or more. Whereas first drives almost always result in a piece of review content, fleet loans only sometimes do. Other times they serve to give context about brands, segments, technology and the like, to editors and writers. So, adding up the loans I've had out of the press fleet and things I've driven at events, my tally for the year is 68 cars, as of this writing. Before the calendar flips to 2015, it'll be as high as 73. At one of the buff books like Car and Driver or Motor Trend, reviewers might rotate through five cars a week, or more. I know that number sounds high, but as best I can tell, it's pretty average for the full-time professionals in this business.

Cadillac boss: Don't ask why we have so many sedans

Ugh, crossovers. Car-based, high-riding station wagons, for some reason, sell in absurd numbers and make automakers lots and lots of money. That's why automakers with a strong lineup of CUVs are running strong, while sedan-heavy brands are struggling. Cadillac is all too aware of this fact. While the company is preparing to launch the new CT6 luxury sedan, it's also realizing four sedans, a coupe, a crossover, and a $73,000, old-school, body-on-frame SUV does not a healthy lineup make. Worse, though, as Cadillac President Johan de Nysschen rued during the LA Auto Show, is that the new CT6 is joining a segment already oversaturated. While it's a big, expensive vehicle, it's not much bigger or more expensive than the CTS and XTS sedans. "Please don't ask me why we have three cars in the same segment," de Nysschen said, stopping midway through an interview with Automotive News on the CT6's market placement to make the crack. "That's a whole different subject." As for those CUVs, the new XT5 debuted in LA, and it will eventually be joined by another much-needed CUV in 2018, AN reports. Related Video: