The eDrive version, says Mornhinweg, “will use exactly the same white body as the gasoline-powered car. There’s plenty of room in the existing structure to put electric motors at each wheel and batteries on the floor, ahead of the firewall, and just aft of the seats. The only change is up front, where we’ll have to change the front axle to a pushrod suspension to accommodate the motors.”
Mornhinweg is clearly excited about the eDrive project. “This is not a concept car. The SLS eDrive will be on the road perhaps as early as 2013—certainly by 2015 at the latest.” As such, it’ll be a continuation of AMG’s goal to reduce fleet-average C02 emissions by 30 percent by 2012. “The challenge for the future is to deliver superb performance, but also social acceptance,” says Mornhinweg. “The internal-combustion engine is going to be around for a long, long time, but to improve its efficiency we’ll be using more and more direct injection, downsizing displacement while adding turbocharging, incorporating stop/start systems, and more. You’ll see more four-cylinder engines in the future, too.”
The AMG boss sees myriad benefits to the SLS eDrive. “The SLS’s lightweight aluminum body and structure will help to offset the heavy batteries we’ll need for maximum performance.” Zero to 60 mph, Mornhinweg adds, will take around 4 seconds flat, with a top speed of about 125 mph. Because each wheel will be driven by its own motor, electric four-wheel drive is inherently part of the design. “By tailoring the software that guides the motors, we can also do exciting things like torque vectoring and dynamic stability control,” Mornhinweg says.
The three modular high-voltage batteries in the SLS eDrive will be lithium ion—powering the four electric motors through two transmissions (one per axle). Peak output is equivalent to 526 horsepower (392 kW) and nearly 650 pound-feet of torque—the eDrive should be a formidable player in stoplight Grands Prix. Range won’t be outstanding—only about 95 to 110 miles—but the batteries will recharge to 80 percent of capacity in around five to six hours (plug in when you reach work if you have a long commute home). Plugging-in overnight will deliver a full charge. (Regen brakes, of course, will help to freshen the batteries when driving.)
Mornhinweg is confident that no major hurdles exist in bringing the eDrive to market. And he emphasizes that the eDrive will not replace the SLS’s 6.2-liter gasoline V-8; the two versions will coexist. “Our biggest challenge,” he notes, ”will be adding the emotion that’s so crucial to the enjoyment of a sports car. For instance, with electric drive there’s no vroom vroom during downshifts, which is a sound every enthusiast driver enjoys. So we’re experimenting with various ways simulate the experience using the two transmissions and the electric motors. I’m confident, though, that when we’re finished we’ll have what many enthusiasts will find a very desirable car.”
