Auto blog

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

Submit your questions for Autoblog Podcast #325 LIVE!

We're set to record Autoblog Podcast #325 tonight, and you can drop us your questions and comments via our Q&A module below. Subscribe to the Autoblog Podcast in iTunes if you haven't already done so, and if you want to take it all in live, tune in to our UStream (audio only) channel at 10:00 PM Eastern tonight.
Discussion Topics for Autoblog Podcast Episode #325
Twin-turbo Cadillac CTS coming

2020 Cadillac XT6 earns IIHS Top Safety Pick award

The 2020 Cadillac XT6 luxury three-row crossover has proven to be plenty competent on the road, and now it turns out to have impressive performance in crash tests. The IIHS recently tested the big Caddy and gave it a Top Safety Pick award. It just missed out on the highest Top Safety Pick + rating because of headlight performance. In every single crash test, the XT6 earned the highest "Good" rating for passenger protection. Both the standard and optional forward collision prevention systems also received the highest "Superior" ratings, and they were both able to bring the car to a stop before colliding with another vehicle at speeds up to 25 mph. The one area it didn't earn top marks was with headlights, which were rated "Acceptable," the second-highest score. Though it doesn't factor into the Top Safety Pick criteria, the IIHS also rated the child seat LATCH anchor access "Acceptable." Among three-row luxury crossovers, there are three others that have the Top Safety Pick rating: the Infiniti QX60, Lexus RX and Volvo XC90. Only one crossover in this segment has the highest Top Safety Pick + rating, and that's the Mercedes-Benz GLE-Class.