SAE Hybrid Vehicle Tech: GM uses real-world data

San Diego--Greetings from southern California, where the Society of Automotive Engineers (SAE) is holding its Hybrid Vehicle Technologies Symposium.


As we did from EVS in December, we'll bring you news, impressions, and thoughts as we go through two days of presentations from major automakers, regulators, and industry analysts.


One of the more intriguing presentations on the conference agenda is called "Driving the Volt," by Peter Savagian. He's director of engineering for GM hybrid powertrains. In other words, the man's got a lot of toys in his sandbox at the moment.


Everyone wants to know what it's like to drive the engineering prototypes, or "mules," of the plug-in hybrid Chevrolet Volt that GM has said it will launch at the end of 2010. It'll be the first production serial hybrid: It will run up to 40 miles (64 km) on its lithium-ion battery pack alone, and then a small engine will run a generator to recharge the batteries for another 300 miles (480 km)--but not directly power the wheels.


I was lucky enough to chat with Pete last night. His paper will have two main thrusts, he said: First, what is driving GM to build the Chevrolet Volt? Groan. OK, fine, GM deserves a chance to present its slides showing growth in the "global car park" and the technologies it plans to use to increase energy independence, reduce consumption, and begin to electrify the fleet.


Second, and far more interesting: What will the Volt be like to drive in the real world? And for this, he revealed, GM is using a new and different set of real-world data, recently gathered from actual Southern California drivers in actual cars.


What's the bottom line? It's that the driving cycles GM is using to benchmark the Volt are tough. Much tougher than the regulatory cycles used by the US Environmental Protection Agency for fuel-economy or emissions testing. And very, very different indeed from those of economy-focused Prius drivers who keep their car in electric mode as long as possible and compare mileage figures like baseball stats.


Why is this data set so significant? Because, like other sprawling suburban areas connected by freeways and six-lane arterials, southern California lends itself to a rapid mix of high-speed driving and bursts of stop-and-go traffic--and its drivers are impatient. As such, it's much more reflective of how average US drivers behave. That's critical for a mass manufacturer like GM, launching a radical electric vehicle like the Volt under its main brand, Chevrolet.


What, asked Savagian, was the median freeway speed from actual SoCal driving data? I guessed 81 miles per hour (130 km/h). I was slightly low; the answer was 83 mph (133 km/h). Or, as he said solemnly, "drivers in LA turned out to be very, ahhhh, aggressive."


(Which is hardly a shock to anyone who's driven out here in the last, oh, 10 years. On my drive yesterday, I was tailgated by a guy in $400 sunglasses yelling on his cellphone while driving a brand-new 3-ton Cadillac Escalade SUV. A stereotype, but true.)


More to come as it happens. I'll be posting at least daily; if any readers have specific issues they'd like me to comment on, please send me a note: J V [dot] spectrum [at] ieee [dot] org.


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