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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

2016 Chevy Volt powertrain technical details

The last time General Motors launched a Chevy Volt, it was operating without really knowing how people would use the plug-in hybrid. Sure, it had experience with the EV1, but the Volt was a new kind of car, and you can see in the archives just how much time GM spent explaining this fresh, new powertrain to potential customers. Then, once the vehicle was released, the company collected voluntary data from a large number of owners to learn about their driving and charging habits. The company also asked them what they wanted most in the new version. There's got to be an algorithm buried somewhere in GM headquarters that was used to take all of the numbers GM collected and spat out the headline figures for the 2016 Volt: 50 miles of EV range and 41 miles per gallon. Another important number – price – is something GM isn't talking about yet (expect it in April or May), but the company is sharing some powertrain details about the upcoming car. At a preview lunch in Detroit last week for the SAE 2015 Hybrid & Electric Vehicles Technologies Symposium that's happening now in California, GM engineers Peter Savagian (who is presenting a paper on the new inverter used in the updated Volt) and Tim Grewe (talking about the entire second-generation powertrain) sat down with AutoblogGreen to tell us about the Volt's all-new propulsion system: The overall gist is that the new Voltec 5ET50 drive unit is lighter, smaller and more powerful thanks to a redesigned two-motor traction drive. As previously reported, the new engine is a 1.5-liter DOHC four-cylinder that offers 101-horsepower (at 5,600 RPM). Grewe said it's "great for range extension." The electric motor side of the powertrain offers 149 motoring horsepower from a two-motor, continuously variable transaxle. Initially, the new engine will be made in Mexico. GM will move production to Flint, MI during the first year it makes the 2016 Volt. The battery is slightly bigger in the new Volt – 18.4 kWh compared to 16.5 in the current-gen – and will have less range variation in the cold. GM is also using more of the overall capacity in the pack in the 2016 Volt than in previous versions, but is not saying how much more. GM is not ready to publish acceleration times just yet, but the 2016 Volt has improved numbers, especially when going from 30-60 miles per hour. Most everything on the new powertrain has become more efficient compared to the first-gen Volt.

GM alerting truck and sedan owners to a do-over on brake recall

A recall campaign intended to address issues with braking systems on certain 2019 General Motors trucks and sedans may have introduced a new issue, the automaker has acknowledged, and thousands of owners driving repaired vehicles may need to return to their service departments for another update.  The update addresses a fix that was pushed out to owners of more than half a million brand-new GM trucks and sedans that could potentially lose partial braking function, according to the Detroit Free Press. The original software fix helped address situations where the vehicles' anti-lock braking systems would become disabled, which in turn would prevent electronic stability control from activating. Vehicles subject to the recall would often experience software glitches that prevented them from properly communicating the operational state of these systems, meaning drivers would have no idea that their brakes may not behave as expected in an emergency. The 2019 Chevrolet Silverado 1500, Cadillac CT6, and GMC Sierra 1500 were all recalled in the original campaign.  Unfortunately, the early version of this fix appears to have introduced yet another software glitch, indicating that the original fix did not do the trick. Those who have not yet had their cars serviced can rest easy; they will only receive the most up-to-date version of the software fix.  Related video