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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 will likely build PHEV batteries in China soon

It's a big week for batteries. Friday, Tesla will hold a big event at its Gigafactory in Reno, NV. But even in Michigan, there are things happening on the electrified automotive front. This was proven when GM invited journalists to its Brownstown Battery Assembly Plant today, highlighting the six different battery packs it makes for nine vehicles around the world (plus a tenth, coming to Asia, that has not yet been announced). During our tour, we learned a few interesting tidbits that we thought readers would like to hear: The Cadillac CT6 plug-in hybrid launches in China this fall before coming to the US next year. GM builds the battery packs in Michigan and ships them to China for final assembly in the PHEV. For now, this is all fine for GM to qualify for China's incentives for building green cars in the country. But, as Bill Wallace, GM's director of global battery systems, told AutoblogGreen, this could change thanks to the country's 'Made in China 2025' plan. The situation is "evolving," he said, and it's a safe assumption that GM will need to build packs in China some day. For the CT6 PHEVs that will be sold in the US, the batteries will make a round trip, since GM will only build the plug-in version in China. As for the range of the CT6 PHEV, that hasn't been announced, but since China offers incentives for vehicles that get at least 50 kilometers (31 miles), that's a likely target (the US range (UPDATE: GM did announce an expected range for the CT6 PHEV in the US at the LA Auto Show last fall, saying it would "travel approximately 30 miles on a full electric charge"). The battery pack in the CT6 is also a clunky box-type thing, totally unlike the near-elegant T-shape used in the Volt. This despite the fact that the guts of the two packs are similar. Both have 192 li-ion cells and weigh almost the same, but GM tuned the CT6 pack for acceleration instead of range, the way it did with the Volt's pack. Still, the main reason the packs are different is because the CT6 is a rear-wheel drive vehicle, and the tunnel that the Volt's pack uses is occupied by the driveshaft. Despite the highly touted second-gen Chevy Volt going on sale last year, GM still has the capacity to build battery packs for the old, first-gen model. This is because the company is legally required to be able to provide replacement packs for warrantied vehicles (for up to 10 years), and the second-gen packs don't fit into the first-gen vehicles.

Watch the 2014 Cadillac CTS live-stream reveal

Despite many an image leaking onto the Internet over the weekend, today is the official day for the debut of the all-new 2014 Cadillac CTS. You want the nitty-gritty details of Cadillac's new sedan? Click here.
If you want to watch the 2014 CTS makes its live debut in front of a throng of auto journalists, then just watch below, as Cadillac is live-streaming the event at 7:15 PM EST. That's only a few minutes from now, so click here to start watching, and stay tuned for our first live images of the CTS from the New York Auto Show.