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Why it's difficult to accurately test the efficiency of a plug-in car

When it comes to electric vehicles and plug-ins in general, the Environmental Protection Agency-certified range is a hugely important number. While actual range anxiety is largely psychological, the magic number does provide a point of comparison of buyers considering one EV over another. The driving distance is also often touted by automakers when marketing their models. Unfortunately, as Green Car Reports finds in a recent deep dive, the way the EPA calculates the figure is a convoluted mess, and discovering the reasons why is definitely worth the read. The issue isn't about bad science but instead comes down to vague wording. The EPA's accepted range test is sourced from an evaluation called J-1634 from the Society of Automotive Engineers, and it seems to provide balanced results for vehicles that automatically reach a single state of charge when plugged in. However for models with multiple charge settings, the situation gets complicated very quickly. Of course, these modes are often created in the software, meaning that a car's certified driving distance can change with just a few taps of the keyboard without the real world results owners might experience actually changing. By showing the test's effects on the certified range for the Tesla Model S, Nissan Leaf and Mercedes-Benz B-Class Electric Drive over the last few years, Green Car Reports makes a compelling argument that it's the evaluation that needs to change. Thankfully, it appears that the solution is a very simple one. Get the details here.

Vision Mercedes-Maybach 6 teases gullwing doors in video

Because these are the times we live in, automakers tease their biggest and best debuts mercilessly before finally dropping the curtain. That's why we're writing about the Vision Mercedes-Maybach 6 Concept again. Here's a new video, posted on Mercedes' Instagram page, showing even more of the hulking two-door coupe. For one, it looks like Mercedes is revisiting gullwing doors. There's a brief snippet of the doors in the open position with a red light – possibly a brake light – bisecting the roof. The video also gives us a couple of good looks at the taillights, which are super-model skinny, just like the lamps up front. Look close at the rear three-quarter cut, and you'll spot a strong chrome strip that accentuates and breaks up those beefy rear haunches. It's hard to tell where they fit in with the chrome strips on the front fenders and hood, so we'll probably need to wait until the big debut to see how it all works out. As we've said twice already, the Vision Mercedes-Maybach 6 debuts on August 18. Stay tuned. This content is hosted by a third party. To view it, please update your privacy preferences. Manage Settings.

Mercedes-Benz engines with 48-volt systems coming in 2017

As part of a big green push announced yesterday, Mercedes-Benz is jumping into the world of 48-volt power. The company will launch a new family of efficient gasoline engines next year and will begin rolling out 48-volt systems with it, likely in its more expensive cars first. Mercedes will use the 48-volt systems to power mild-hybrid functions like energy recuperation (commonly called brake regeneration), engine stop-start, electric boost, and even moving a car from a stop on electric power alone. These features will be enabled through either an integrated starter-generator (Mercedes abbreviates it ISG) or a belt-driven generator (RSG). (RSG is from the German word for belt-driven generator, Riemenstartergeneratoren. That's your language lesson for the day.) Mercedes didn't offer many other details on the new family of engines. There are 48-volt systems already in production; Audi's three-compressor SQ7 engine uses an electric supercharger run by a 48-volt system, and there's a new SQ5 diesel on the horizon that will use a similar setup with the medium-voltage system. Electric superchargers require a lot of juice, which can be fed by either a supercapacitor or batteries in a 48-volt system. Why 48-volt Matters: Current hybrid and battery-electric vehicles make use of very high voltages in their batteries, motors, and the wiring that connects them, usually around 200 to 600 volts. The high voltage gives them enough power to move a big vehicle, but it also creates safety issues. The way to mitigate those safety issues is with added equipment, and that increases both cost and weight. You can see where this is going. By switching to a 48-volt system, the high-voltage issues go away and the electrical architecture benefits from four times the voltage of a normal vehicle system and uses the same current, providing four times the power. The electrical architecture will cost more than a 12-volt system but less than the complex and more dangerous systems in current electrified vehicles. The added cost makes sense now because automakers are running out of ways to wisely spend money for efficiency gains. Cars can retain a cheaper 12-volt battery for lower-power accessories and run the high-draw systems on the 48-volt circuit. The industry is moving toward 48-volt power, with the SAE working on a standard for the systems and Delphi claiming a 10-percent increase in fuel economy for cars that make the switch.