Dartmouth Engineer - The Magazine of Thayer School of EngineeringDartmouth Engineer - The Magazine of Thayer School of Engineering

Competition: Formula Hybrid Comes of Age

By Calvin Krishen Th’08

Five years ago, Formula Hybrid started as a small exhibition of one car from Dartmouth and one from McGill University. The event was a proof-of-concept demonstration that a small, open-wheel race car could house a hybrid power train. Dartmouth’s car wasn’t so small. It weighed 1,200 pounds — three times more than its gas-powered peers. It also wasn’t very good at racing. It steered like a cruise liner. But the point wasn’t to make it fast or race around a track. The point was to call attention to contemporary challenges in engineering and invite universities around the world to tackle new technologies.

FINAL PREPS: From left, Yoon-Ki Park ‘09 Th’10, David Lindberg ’09 Th’10, and Steven Walker ‘09 Th’10 fine-tune Dartmouth Formula Hybrid’s race car, Penny.  Penny is the first DFR car with a parallel hybrid drivetrain. Photograph by Kathryn LoConte.
FINAL PREPS: From left, Yoon-Ki Park ’09 Th’10, David Lindberg ’09 Th’10, and Steven Walker ’09 Th’10 fine-tune Dartmouth Formula Hybrid’s race car, Penny. Penny is the first DFR car with a parallel hybrid drivetrain. Photograph by Kathryn LoConte.

Every year since then a growing number of colleges and universities answered that invitation. In May, 26 of the 30 registered teams made it to the Thayer-hosted Formula Hybrid International Competition at the New Hampshire Motor Speedway in Loudon, bringing with them the most advanced entries the competition has seen.

Were the cars small? Oh, yes. Some weighed less than 500 pounds, thus rivaling gas-powered equivalents. They are also very fast. Most can go from 0 to 60 mph in approximately four seconds — which approaches Porsche territory. Not bad for something that runs on rechargeable batteries.

Formula Hybrid 2010 boosted the competition to a whole new level. Teams have finally figured out the technology and are battling for points in every single event. No car from 2009 other than Texas A&M’s could come close to competing with the cars of 2010. This year, the winner, Italy’s Politecnico di Torino, was described by one judge as a professional racing outfit. Yet the team outpaced Texas A&M by a mere three points of a possible thousand. Now we’re racing!

Dartmouth's 2010 entry, Penny, races in the autocross event. Photograph by Kathryn LoConte.
Dartmouth's 2010 entry, Penny, races in the autocross event. Photograph by Kathryn LoConte.

After A&M and Torino, the other top slots shuffled between Dartmouth, University of Wisconsin-Madison, UC Davis, and Brigham Young University (BYU). Many first-year teams also performed well — which is no easy feat. Yale made it to design finals, and BYU and UC Davis edged out veterans Wisconsin and Dartmouth (3rd, 4th, 5th, and 6th place, respectively). Florida A&M-Florida State University and San Jose State University, while slower, were also first-year teams that scored and completed all of the events. As design judge Andrew Burston of Flux Dynamics put it, “It’s been a great year. There’s been a fantastic range of teams. The bar has been raised. Definitely.”

One mark of progress is that a superior drivetrain configuration has emerged: a simple, mechanically coupled, parallel system. It weighs the least, has built-in redundancy (if the electric motor fails, there’s still an internal combustion engine), and opens the door for regenerative braking.

If this year is any indication of how teams will compete in the future, we can look forward to some great engineering — and some real racing.

Ongoing Challenges in Formula Hybrid

Here are three areas that Formula Hybrid teams will need to master to keep the technology moving ahead.

Power electronics: These are the components of the car that convert stored electrical energy into usable mechanical energy. The energy is stored in accumulators, such as battery packs or ultra capacitors. Energy flows from the accumulators through a device called a motor controller. The controller is like a valve that lets the energy through to the car’s electric motors. Really good motor controllers allow for regenerative braking. The electric motor is then used as a generator to pump energy back in to the accumulators. So far, teams have been using off-the-shelf units with limited regenerative capabilities. Teams that figure out this piece of the puzzle will undoubtedly beat the fuel allotment next year.

Control software: If the motor controller is like a valve, then the control electronics would be a little scientist in a white labcoat who knows when and how much to open and close that valve. Software is not only the key to controlling and extracting energy from the accumulator system, it is also critical for assisting the car’s internal combustion engine where it is least efficient. To play the fuel efficiency game, teams with savvy software and engine people will need to spend a lot of time programming and tuning the timing and magnitude of the electric motor’s output.

Lightweight materials and composites: If you want to be fast in hybrid, you have to be light. The fuel allotment is strict — it’s half the fuel allotment for a regular Formula SAE (FSAE) car. Torino purposefully prevented their drivers from going full throttle just so that they could finish the race. If the cars are to get any faster, teams are going to have to figure out clever ways of dropping vehicular weight. Keeping the chassis light, yet maintaining stiffness for the speeds these cars operate will take some very careful analysis and design.

The Politecnico di Torino teammates, with their light race car, take stock of their performance after the autocross event. Photograph by Kathryn LoConte.
The Politecnico di Torino teammates, with their light race car, take stock of their performance after the autocross event. Photograph by Kathryn LoConte.

The difficulty with all three of these more contemporary engineering problems is that they are difficult for undergraduates to perfect in just one year. Undergrads have the basic knowledge to build these systems, but making them race-ready is a different challenge. Formula Hybrid teams will need to start recruiting more graduate students to carry the load of these more advanced design issues. That’s how Torino did it, in fact. Their car was the culmination of a half-dozen or so master’s theses. That and their driver was on a scholarship — for driving.

Disparity in resources has always existed in FSAE as well as Formula Hybrid, and, I think, is actually part of what makes the competition exciting for judges and competitors. Cars built by schools like Torino go head-to-head with cars built on a shoestring budget. Engineers with far fewer resources have to be more selective and strategic about the design battles they choose. The teams with fewer resources come up with design ideas that surprise us all.

—Calvin Krishen Th’08 was a member of the 2008 Dartmouth Formula Hybrid team.

Categories: The Great Hall, Competition

Tags: energy, formula hybrid, history, international, projects, race cars, students

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