Lightweight, Aerodynamic, Efficient Designs Win Progressive Insurance Automotive X-Prize

Jan. 14, 2011
Is there a 100-mpg vehicle with 200 miles of range in your driveway?
AC Propulsion,
Li-ion Motors Corp.,
Progressive Insurance Automotive X-Prize,

There will be, if the winners of the Progressive Insurance Automotive X-Prize competition have anything to say about it.

The competition ended this past fall with half the $10 million purse going to Mainstream Class entrant Very Light Car #98 (VLC) from Edison2, Charlottesville, Va. Two Alternative-Class winners, Wave II from Li-ion Motors Corp., Mooresville, N. C. and E-Tracer by the X-tracer team from Peraves, Winterthur, Switzerland, split the remaining $5 million.

Running requirements
The contest ran over a year during which the field narrowed from 136 to the three class winners. The ultimate goal was to design a market-ready car that could go 200 miles without refueling or recharging, and achieve 100 miles/gallon-equivalent (mpge — see sidebar). Alternative entries — cars that carried fewer than four adults or had fewer than four wheels — had the same efficiency target but only a 100-mile range goal.

In keeping with the concept of market-ready designs, vehicles needed to carry standard features like enclosed or convertible cabins with windows; a windshield and wipers; seat belts and head restraints; rear and sideview mirrors; headlights, brake lights, and turn signals; driver instrumentation; one control for braking, one for acceleration, and one for steering; and a parking brake. The vehicles had to be highway capable and create no more than 74 dB of noise.

And although it seems to go without saying for a market-ready car, vehicles had to stay upright when stopped or when they lose traction, protect occupants in case of rollover, keep at least three wheels on the ground during emergency lane changes, and have enough ground clearance to clear typical driveways.

Finally, vehicles in the Mainstream Class had to carry at least four passengers — two 95th percentile adult males  (6 ft, 2 in. and 215 lb) in the front and two 75th percentile adult males (5 ft, 11 in. and 210 lb) in the back — and have 10 ft3 of contiguous cargo space.

Alternative-Class vehicles needed to carry at least two 95th percentile adult males either side by side or in a tandem configuration. For these vehicles, there was no restriction on the number of wheels.

Vehicles had to burn gasoline (E10), ethanol (E85), biodiesel (B20), compressed natural gas (CNG), or use electricity. Electric vehicles had to fully charge within 10 hr on power sources up to 240-V, 40-A continuous ac.

Very Light Car
Mainstream Class winner Very Light Car #98 from Edison2 has a curb weight around 800 lb. The four-wheeler is 167-in. long with a 100-in. wheelbase and 70-in. track width both front and rear. In addition to carrying four adult passengers, it can hold up to 22 ft3 of cargo.

Steel-tube framing protects passengers while a stressed skin let designers pare structural weight. Using a 250-cc, single-cylinder engine that burns E-85 ethanol also saves weight that would have gone to battery packs. Edison2 engineers concluded early in their design process that the mpge boost from efficient electric drives is cancelled out by battery weight.

The car’s 0.16 drag coefficient is another factor that lets the vehicle average 102.5 mpge and go over 600 miles on a 6.5-gallon tank. Even with the combustion engine, the VLC emitted only 87.7 gm of CO2/mile.

Wave II
The Wave II, winner of the Alternative – Side-by-Side Seating Class, is a four-wheeled two-seater from Li-ion Motors Corp. The car scored 187 mpge and clocked a 0-to-60 time of 14.7 sec. The performance is due to a slippery 0.153 drag coefficient and light weight.

The aluminum-skinned car weighs 2,176 lb, despite a heavy Li-ion battery pack and a steel roll cage. The batteries that let the Wave II meet the 100-mile range requirement for alternative-class vehicles recharge in 8 hr.

Li-ion Motors team leader, Ron Cerven, says, “Li-ion Motors intends not only to manufacture our cars in the U. S., but also license our technology to automotive manufacturers worldwide.” Future plans include continued development of their proprietary Battery Management System (BMS) with the aim of boosting efficiency an additional 10 to 20%.

The E-Tracer, winner of the Alternative - Tandem Seating Class, is a Peraves’ Monotracer enclosed motorcycle converted to electric operation. Twenty-kW-hr, 420-V, 55-Ahr lithium-ion batteries behind and below the passengers replaced the Monotracer’s 1,171-cc BMW engine. The batteries account for 276 lb of the E-Tracer’s 1,436 lb, deliver an efficiency of 205.3 mpge, and recharge in 1.5 hr at 240 V and 80 A.

A drive from AC Propulsion, San Dimas, Calif., uses the battery power to deliver 811 lb-ft to the rear wheel and accelerate the vehicle from 0 to 60 mph in 6.6 sec. Top speed is electronically capped at around 150 mph.

The two-wheeled vehicle can safely tilt to 58° around corners. Outriggers deploy to keep the vehicle upright on slippery roads, at low speeds, and when stopped. A 22 × 14 × 9-in. luggage compartment sits behind the rear passenger.

According to Jim Lorimer, U. S. sales representative for the Monotracer and E-Tracer, “Due to the performance of the vehicle, and the associated sticker price, people who paid attention to the X-Prize competition are not typically in our market. However, we plan to bring the E-Tracer to market, and are probably closer to doing so than any of the other X-Prize competitors.” The E-Tracer is expected to debut next autumn at $110,520.

Mpge: What does it mean?
Mpge is a pump-to-wheels energy-efficiency figure that expresses fuel economy in terms of the energy content of 1 gallon of gasoline. The calculation asks how much energy was delivered to the vehicle and how far it went:

mpge = (miles driven) / [(total energy consumed)/(energy of 1 gallon of gasoline)]

Vehicles were also rated on their greenhouse-gas (GHG) emissions in equivalent grams of CO2/mile. The estimate includes GHG contributions from fuel extraction, production, distribution, and consumption. Vehicles emitting more than 200 gm/mile of CO2 were eliminated early.

The X-prize experience
The X-Prize competition was broken into several phases: an initial judging phase, knockout testing, on-road and dynamic safety testing, and coast-down testing.

Initial Judging: Officials reviewed entrants’ plans for safety and emissions, manufacturability and cost, features, and bringing the vehicle to market. 136 --> 36

Shakedown: A high-mileage race reflecting consumer driving patterns, driving conditions, and terrains let teams work out the bugs. Vehicles had to prove they met safety standards to advance. 36 --> 27

Knockout: Teams had to hit range and efficiency levels of at least two-thirds of the ultimate goals. 26 --> 15

Finals: On-road fuel-economy/efficiency testing mimicking EPA city, urban, and highway testing; on-road-range testing with full tanks and fully charged batteries; acceleration and braking, accident avoidance, and highway acceleration safety tests was the final proof of cars abilities. 15 --> 9

Validation: Cars were coasted down from 80 mph to establish aerodynamic and mechanical drags and tire rolling resistance for dynamometer testing. Dynamometer and road-test results were averaged for the final ranking. 9 --> 9

Winners: The teams with the best combined efficiency and range scores in each category won the prize. 9 --> 3

© 2011 Penton Media, Inc.

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