In 2014, the US Department of Energy launched EcoCAR3, a four year competition that challenges engineering students to redesign a Chevy Camaro, making it a hybrid electric vehicle while maintaining its muscle car performance. The competition is "graded" annually, with different milestones evaluated each year. In the first year, the emphasis was on design and simulation. This year, prototypes were tested for safety and performance under various conditions. An engineering team from The Ohio State University took first place in both years, capping off three consecutive years that the Buckeyes have brought home the gold, having won the finals in the EcoCAR2 challenge in 2014.
Team leader Andrew Huster was kind enough to send me some of the details of the OSU design while the team traveled home from the competition in California.
Dual-Mode Hybrid Powertrain
The modified Camaro's muscle is derived from an electric motor and a gasoline engine. The car can operate in economy mode, running fully electric until the battery is depleted, at which point the engine provides additional range. It also features a performance mode, where the gasoline engine and the electric motor operate in parallel, delivering nearly 300 horsepower and a top speed of 137 km/h (85 mph).
The electric drive comes from a 112 kW Parker Hannifin GVM210-150, a variable frequency AC motor that's capable of providing 150 hp and 250 Nm of peak torque, while weighing only 45 kg (100 lbs). It's paired with a 2.0L GDI E85 engine, which puts out 160 hp and weighs 102 kg (225 lbs). I wondered why they opted for E85 fuel, which carries less energy per unit of mass compared to regular gasoline. Andrew Huster explained that the team "conducted a number of simulations for each permitted fuel type (E10, E85, and B20) and determined that E85's benefits, such as a higher octane rating that allows use of engines with greater compression efficiency, and reduced well-to-wheel greenhouse gas emissions, outweighed the reduced energy content of the fuel relative to conventional gasoline." The engine itself is flex-fuel, so it could run on standard gasoline, but for the purpose of the EcoCAR3 competition, it runs only on E85.
The powertrain sports a 5-speed Tremec T5 Automated Manual Transmission. That's a manual transmission with an automated clutch, giving the performance and fuel economy of a stick-shift with some of the convenience of an automatic. At 34 kg (75 lbs), the transmission brings the total weight of the powertrain up to 181 kg (400 lbs).
Battery Bank
The electric fuel tank, so to speak, is an 18.9 kWh LiFePO4 (Lithium Iron Phosphate) battery pack made by A123 Systems. [ At 204 kg (450 lb), the batteries outweigh the entire powertrain.] Lithium iron phosphate batteries have many of the same benefits of Li-ion batteries, but without Li-ion's propensity to catch fire when damaged. The battery bank gives the car a range of 72 km (45 mi) on electric power alone, so the average commuter can easily use this car as an EV most of the time, and a hybrid for longer excursions.
With the first two years behind them, EcoCAR3 teams will continue to refine their designs (year three) and then shift the focus to marketing in year four. Good luck to all the teams!
Click here to see the official press release.
Images courtesy of US Department of Energy
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