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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.

2021 Chevy Tahoe, GMC Yukon fuel economy and towing capacities go official

Most of the puzzle pieces have fallen into place with GM’s new full-size SUVs, but today we have fuel economy and towing to add to the picture. Numbers for the standard 5.3-liter V8 and upgrade 6.2-liter V8 are out, but GM has held back on the 3.0-liter turbodiesel inline-six for the time being. Those numbers are most likely not ready yet. Minor improvements and decreases are seen throughout the Tahoe/Suburban and Yukon/Yukon XL lineup. Because there are so many variants, weÂ’re going to just lay them out below for you. 5.3-liter V8 2021 Tahoe/Yukon 2WD: 16/20/18 2021 Tahoe/Yukon 4WD: 16/20/18 2021 Suburban/Yukon XL 2WD: 16/20/18 2021 Suburban/Yukon XL 4WD: 15/19/17 6.2-liter V8 2021 Tahoe/Yukon 2WD: 15/20/17 2021 Tahoe/Yukon 4WD: 14/19/16 2021 Suburban/Yukon XL 2WD: 15/20/17 2021 Suburban/Yukon XL 4WD: 14/19/16 As you can see, there isnÂ’t a whole lot of difference between two-wheel drive and four-wheel drive options. You can eke out an extra mpg here and there, but itÂ’s a penalty weÂ’d be happy to live with to have four-wheel traction. The biggest loser in all of this is highway mpg. Chevy has made the trucks bigger and added weight with the independent rear suspension, causing a decrease in fuel economy. For example, a 2020 Tahoe with the 6.2-liter V8 and four-wheel drive is rated at 14/22/17. The 2021 truck drops 3 mpg on the highway and 1 mpg in the combined rating. There are improvements to be found, though. A 2020 Suburban with the 5.3-liter V8 and four-wheel drive is rated 14/21/16. Fuel economy in the city goes up 1 mpg, but you lose 2 mpg on the highway and 1 mpg in the combined rating. ThereÂ’s a bit of give and take here, but at least a slight increase in city mpg has accompanied the greater loss in highway fuel economy. 2021-chevy-tahoe-chicago-01 View 12 Photos As for towing, the Tahoe/Yukon with the 5.3-liter V8 and two-wheel drive has a new 7,900-pound capacity, and the four-wheel drive model is rated at 7,700 pounds. Respectively, those are the best figures youÂ’ll get with the standard towing capacity. Opt for the maximum towing package, and the Tahoe/Yukon capacities go up to 8,400 pounds (two-wheel drive) and 8,200 pounds (four-wheel drive). The numbers all take slight cuts when you go for the 6.2-liter V8. Both the Suburban and Yukon XL offer similar or identical towing figures as their shorter counterparts do.

Recharge Wrap-up: NEDC's NOx problems, autonomous Chevy Volts

The International Council on Clean Transportation (ICCT) found a significant difference in NOx emissions in Euro 6 diesel cars in NEDC and WLTC testing. While 88 percent of the cars tested met emissions standards for NEDC, NOx emissions averaged five times higher under WLTC, with only 27 percent of vehicles under the limit. WLTC is considered to be a more realistic driving cycle, using hot starts and factoring a higher top speed as well as harder and more frequent accelerations than the NEDC. Read more at Green Car Congress.GM Canada will build a fleet of autonomous 2017 Chevrolet Volts. The self-driving Volts will be deployed for testing at GM's Warren, Michigan Technical Center. Employees will be able to use a carsharing app to reserve a car, which will then drive itself to the set destination. The project will allow GM to collect important data and experience to help the company more quickly develop autonomous driving technology. Read in a press release more from GM Canada, or at Green Car Congress.Carwatt is showing an electric Renault Trafic powered by second-life batteries at the COP21 environmental summit in Paris. The lithium-ion batteries used to power the EV were recycled from other Renault EVs. With the electric Trafic, Carwatt – a company that converts vehicles to use electric power – aims to demonstrate the "circular economy" of batteries, which can provide more value through a longer lifecycle. Read more in the press release below. Carwatt presents a unique automotive application for second-life batteries from electric vehicles. On the sidelines of the COP21 summit, in the Solutions Gallery running from 2 to 9 December 2015 in Le Bourget near Paris, Carwatt and its partners —Renault, Paris City Council, BPI France, the Ales Ecole des Mines Engineering School, and the Bobigny Business Campus — are showing a very special electric Renault Trafic. This prototype vehicle, the only one of kind in the world, is powered by second-life lithium-ion batteries recycled from Renault electric cars. Circular economy at work with electric vehicles When, over time, the batteries of a Renault electric vehicle fall the performance threshold specified for their initial automotive power duty (around 75% of initial capacity), they can still provide valuable service in "second-life" applications before end-of-life disposal at a recycling centre. Experiments are already under way on power storage applications, for example.