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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.

GM executive chief EV engineer says reducing cost of plug-in vehicles is 'huge priority'

As we know, another major automaker investing heavily in electrified vehicles is General Motors, and it's doing things much differently than rivals BMW, Ford or Nissan. The Chevrolet Volt extended-range EV is a modest seller at its $35,000 sticker price but a huge hit with owners. The Chevy Spark BEV, still in limited availability, puts smiley faces on its owners and drivers. The just-introduced Cadillac ELR, a sharp-looking, fun-driving $76,000 luxocoupe take on the Volt's EREV mechanicals, has admittedly low sales expectations. With this interesting trio in showrooms and much more in the works, the third vehicle electrification leader I collared for an interview at Detroit's North American International Auto Show (see #1 and #2) was Pam Fletcher, GM's executive chief engineer, Electrified Vehicles. ABG: Why do your EREVs need four-cylinder power to extend their range when BMW's i3 makes do with an optional 650 cc two-banger? "We designed [the Volt and the ELR] to go anywhere, any time" - Pam Fletcher PF: I get that question all the time: why not something smaller? You don't really need that much. You use the electric to its ability, then you just need to limp. But we designed those cars to go anywhere, any time, and we don't want their performance to be compromised. If you're driving through the mountains, we don't want you to be crawling up grades, or to be limited on any terrain. So it's optimized to be able to travel literally the biggest grades and mountain roads around the globe at posted speeds. Because what if you can't? Another good reason: when the engine is on, you have to run it wide open throttle, max speed, most of the time. And while we can do a lot with acoustics, and the ELR has active noise cancelation, a small-displacement, low cylinder-count engine at high speed, high load all the time isn't something you want to live with. That's how we came up with the balance we did among the key factors of performance, NVH [noise, vibration and harshness] and range. ABG: Where you go from here? Is the range-extender engine due for an update? PF: We know and love the current Volt, and there is still a lot of acclaim about it, so we think it's a good recipe. But we are heavily in the midst of engineering the next-generation car, which I think everyone will love and be excited about.

Chevy says not to look at the 2019 Silverado's fuel economy rating

The 2019 Chevy Silverado is hitting dealerships soon, and one of the most notable changes for the new full-size pickup is the addition of a 2.7-liter turbocharged inline-four. The engine replaces the naturally-aspirated 4.3-liter V6 in volume consumer models like the Silverado LT and promises more power, less weight and — most importantly — better fuel economy. The thing is, the gains in efficiency haven't been as dramatic as some might have hoped, especially when stacked up against competitors from Ford and Ram. As Automotive News reports, GM's response is a little murky. First, let's talk numbers. We're pulling all figures from FuelEconomy.gov, the official U.S. government source for fuel ratings. Fuel economy numbers on trucks vary greatly based on a number of factors. Bed and cab configuration play a part, but so does a four-wheel-drive system. You also have to factor in tires, transmissions, rear-axle gearing, hybrid systems and cylinder deactivation. Things like that can make the difference between best- and worst-in-class. The EPA's website doesn't give enough information a lot of the time, so there's really no easy way to compare apples-to-apples. First, take a look at the ratings for the 2019 Silverado. A 2.7-liter model with two-wheel drive is rated 20 city, 23 highway and 21 combined. That's both better and worse than a two-wheel drive 2018 Silverado with the 4.3-liter V6 (18 city, 24 highway and 20 combined). The updated 2019 Silverado with a 4.3-liter V6 has yet to be rated. With less weight and a smaller engine, many hoped Chevy would make bigger gains. It's unusual to see any decrease in a fuel economy metric these days. GM says that it's not done tuning the new 2.7-liter engine, so fuel economy could theoretically increase. Expanding further, a V8-powered 2019 Silverado (17 city, 24 highway and 19 combined) actually gets better highway fuel economy than a turbocharged four-cylinder powered truck in certain configurations, even if the latter has a better overall average. But that's only with two-wheel drive, the 8-speed transmission and cylinder deactivation. A Silverado with the 5.3-liter V8 and a 6-speed automatic is rated at 15 city, 22 highway and 17 combined. The biggest issue with the Silverado 2.7-liter doesn't come from within GM itself but from Ford and Ram. GM cites the Ford F-150 with the 3.3-liter V6 and the Ram 1500 with the 3.6-liter V6 as the closest competitors to its new 2.7-liter inline-four.