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How GM engineers are using diaper 'snow' to keep you warm

Testing how snow affects General Motors' vehicles isn't really a problem right now for the company's engineers, but in the dog days of summer the process isn't exactly easy. The only real option is for them to book time at the automaker's climatic wind tunnel. However, a flash of brilliance from an engineer allows snow to be simulated regardless of the temperature outside, and the discovery is all because of his daughter's wet diaper. The realization came to GM Thermal Systems engineer Nicholas Jahn while he was swimming with his daughter and noticed how her diaper ballooned in size in the water. He found out the substance that makes this possible is called sodium polyacrylate. When the material gets wet it grows and forms fluffy flakes that are a close imitation of snow. Best of all, the stuff can be prepared easily any time of the year, and it's reusable. The engineering team uses the material to test the effectiveness of the heating systems of GM's vehicles. They spread the sodium polyacrylate over the inlets at the base of the windshield to obstruct the airflow and then crank the heater. After some time, they can see how much is being sucked into the system and design more efficient systems in the future. See how the process works in the video above and read about the diaper discovery in GM's press release below. Diapers Change Chevy Cruze Winter Warm-up Time GM validation engineer uses diaper material "snow" to reduce frigid drives 2015-01-06 DETROIT – An item commonly found on an infant's changing table is helping General Motors' engineers simulate snow year round, ensuring heating systems in cars like the 2015 Chevrolet Cruze can quickly and efficiently warm its interior. Packed snow can prevent air from entering the inlet panel at the bottom of the windshield, obstructing the flow of air into the heating system and reducing the amount of air it can push out. This can lead to less efficient warming of the car's interior and windshield defrosting. "The last thing anyone wants to do when it's freezing cold out is scrape their windshield," said Nicholas Jahn, GM Vehicle Thermal Systems engineer. "The testing we perform on the Chevrolet Cruze with the diaper material allows us to maximize the car's heating capabilities." Ironically, Jahn stumbled upon his diaper-based testing method in the middle of summer. During a swim with his daughter, he noticed her diaper multiplied in size when it came into contact with water.

'Killing a Duramax' Gale Banks YouTube series methodically tunes a diesel to death

Learning or perfecting a skill by watching YouTube videos is known as attending YouTube University. GM Authority picked up on one of the video site's more fascinating courses, hosted by Gale Banks; in a fair world, he should be referred to as Professor Banks when it comes to diesel engines and truck tuning. A few months after GM introduced the updated L5P 6.6-liter Duramax diesel V8 in the 2020 Chevrolet Silverado HD and GMC Sierra HD that ships with 454 horsepower and 910 pound-feet of torque, Banks decided he wanted to methodically tune the engine to death. The purpose of the resulting series, called "Killing a Duramax," is to push more power out of the engine in order to discover which parts break and when — or, as Banks puts it, force-feed the Duramax "until the crank hits the street and the heads hit the hood." With that knowledge, Banks can figure out all the weak points on his way to building what he calls a "Superturbo," that being a supercharged, twin-turbo race engine with more than 1,000 hp. What makes the series fascinating is Banks' knowledge, paired with the company's comprehensive iDash engine monitoring system that keeps tabs on a glut of parameters every step of the way. So for instance, you get Banks explaining the differences between inches of mercury and barometric pressure, how those are different from the water content of the air measured in grains, then showing those readouts on the iDash, then explaining in detail how they affect the air density in the Duramax system. The stock Borg-Warner variable turbo gets a lot of airtime — Banks accuses it of being "out to lunch" because he feels it's the weakest link on the engine. That turns into a turbo teardown and a deep explanation of performance pitfalls, such as when air pressure on the turbine begins to diverge from the boost pressure coming from the compressor. Banks says he can keep close tabs on where power's coming from, because the iDash monitors the horsepower contribution provided by the ambient air, the turbo, and the intercooler separately. The major changes so far are a stouter Precision 7675 turbo and TurboSmart wastegate (episode 5), a twin intake (episode 6), a custom liquid-cooled intercooler from a marine engine, a new GM oil cooler and synthetic oil (episode 10), and new injectors (episode 11).

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.