Revving up: Buckeye Bullet team boosts automotive technology
One morning on the Bonneville Salt Flats, Venturi Buckeye Bullet 3 team members explained their electric vehicle technology to a captivated audience of one: Col. Chris Hadfield, the first Canadian astronaut to walk in space.
In return, he regaled the team with comparative stories about his flights in space shuttles and fighter jets. Incredibly, the team and Hadfield have faced similar challenges: managing heat produced by high-speed motors, stopping vehicles that move so fast, developing the best computer analyses for control systems adjustments.
“What a beautiful machine,” said Hadfield, who came to see the Bullet at the invitation of Gildo Pastor, CEO of team sponsor Venturi Automobiles. “I appreciate you guys taking the time to show me. That’s a huge amount of engineering in a very compact package.” (Yes, that is the Hadfield of “Rare Earth” and “Space Oddity” YouTube fame.)
“Seeing Col. Hadfield's interest in the Bullet validated the pride that I have in the Bullet. To see such interest from someone who has piloted some of the world’s most advanced flight vehicles was genuinely flattering,” says Frankie Gonzalez, an aerospace engineering major. “As he told his flight stories, I could only imagine the forces he felt during a high G-force turn or the immense deceleration while landing on an aircraft carrier.”
The students on the Venturi Buckeye Bullet 3 (VBB3) team are investigating their next route after their September trek to set a new record on the Bonneville Salt Flats, which unfortunately turned into a shallow lake after 12 straight hours of rain. In fact, this year marked four of the past five in which major rains have caused delays, complications or cancellations in the Bullet’s world record speed attempts.
Their world-record 341 miles per hour, set in 2016, still stands, but the team is confident in the electric vehicle’s abilities to reach 400 mph — a speed considered the dream goal in many auto racing categories. Such an attempt requires the best of track conditions, so they are evaluating potential racing sites in the United States and around the world. Meanwhile, in collaboration with industry partners, they continue to accelerate vehicle technology en route to becoming the next generation of automotive engineering leaders.
Driving the Student Experience
David Cooke, researcher at the Center for Automotive Research and former Bullet team member, points out the connection between students’ participation on the team and their classroom education.
“All this is being done at the hands of students, so you get an interesting mix of passion and experience,” he says. “At the same time that they are hearing about equations or techniques in the classroom, they’re seeing it put into practice in the car.”
Gonzalez says he has worked on the motors, transmission and batteries in the car and hopes to apply what he has learned in aerodynamics to a career in aerospace, the automotive industry or cycling.
“I have also read the work of the aerodynamic specialists that have come before me. The main goal as far as the aerodynamics of the car are to minimize the aero drag, while creating stability at high speed,” he says. “Stability is the reason behind the vertical tail fin, the most striking element on the car.”
Mechanical engineering major Peter Bruce also knows his work on the team is a unique opportunity.
“I go to class with plenty of people who have never turned a wrench in their lives,” Bruce says. “The Buckeye Bullet is a one-of-a-kind vehicle. You won’t find anything like it in the world. Because of that, we have to make specialized parts for it.”
Innovations for the Auto Industry
Those specialized parts have included the major components of a powertrain: motors, inverters and batteries, and energy storage.
“Vehicle technology is born and tested on race tracks,” says Cooke. “Innovations in performance and safety came because racers needed them.
“In our case, while we love racing out here on the Salt Flats, the reason Ohio State is here is not because we need the world’s fastest vehicle,” Cooke says. “It’s to push the technology’s limits.”
No parts of the Bullet’s powertrain or energy storage systems are off-the-shelf components; they have all been new or pre-production technologies, and the students worked with automotive experts in every area.
“The idea is to take the prototype parts and put them in the hands of great young students to push the technology under extreme usage,” Cooke says. “And the manufacturers are very interested in the data and results. They didn’t sell us a part they know works; we work with them to push their product in a new way.”
For example, the team worked closely with Rinehart Motion Systems LLC (RMS) on an inverter product critical to the Bullet.
“Compared to a road electric vehicle, the VBB3 project represents some challenges, especially concerning the voltage (up to 900V), peak power request (up to 1.5MW), device and cooling packaging,” says Matilde D’Arpino, an Ohio State research associate leading the VBB3 electrical team. “As matter of fact, in the past the inverter design has been affected by technology limitations that limited the performance of the VBB3.”
RMS has expertise about power electronics with a special focus on motorsports, off road vehicles, and trucks, D’Arpino says, and the company’s products are internationally recognized as suitable for special applications, such as the hybrid electric hardware for the Formula 1 race cars.
“In their catalogue they have an inverter that was almost fitting our specifications. It has a great density of power and great cooling performance,” D’Arpino says. “(But) the operative voltage level was lower than what our vehicle needs to give off the full performance.”
RMS President Larry Rinehart connected with Buckeye Bullet team members at a trade show several years ago and noted their professionalism.
“Of course when a car is going that fast, they have to be professional and very thorough. The educational experience that the people involved get is much more valuable to them because they get exposed to much more of the problem at that high a level,” he says.
At the time, RMS was developing new inverters based on a need to provide higher power in a very small package, so the Bullet’s needs coincided with the product development. Because of the Bullet’s unique transmission system, the company also helped develop software to make the inverters work with the transmission.
Now, RMS can use the Bullet as a success story for the inverters for its professional motorsports customers.
“We can point to that vehicle and say, ‘We’re going to be going 400 mph,’” he says. “The Buckeye Bullet has a high sustained run, so there is a unique thermal application. We benefit from exercising the inverter in the Bullet’s very different environment, so it helps us understand how robust our inverter is. We also get a data log from the run that shows any problems. That helps us define the protection of the inverter and avoiding having it shut off when it doesn’t have to.”
It’s not just product testing but also research results from the Buckeye Bullet that help fuel developments in the automotive industry.
The VBB3 provided the case study for CAR researchers to develop a computer simulation and modeling tool, VBB3Sim, to support the design, optimization and characterization of electric vehicles, especially for racing applications. The tool offers flexibility, accurate dynamic performance and fast computation suitable for real-time testing. For vehicle performance predictions that a driver could use — for shifting strategy, for example — it takes into consideration not only the state of the vehicle such as its speed, battery voltages and axle loads but also variables ranging from the racing surface to driver response to wind speed and direction.
“We are going to use the collected data of this year,” says D’Arpino, one of the VBB3Sim developers, “to improve the model calibration for future Venturi Buckeye Bullet improvement and/or for the development of new racing vehicles.”
Electric Vehicles’ Coming of Age
Ford Motor Chair in Electromechanical Systems and Professor Giorgio Rizzoni, director of the Center for Automotive Research and faculty adviser to the Buckeye Bullet team, says all auto companies are now involved in electric vehicle development. Consider GM’s recent promise of a move toward zero emissions: a plan to have at least 20 all-electric vehicles by 2023.
“Ten years ago, electric vehicles were a curiosity. Five years ago, there were early believers and early adopters,” he says of the auto industry. “Today, we believe this is a development that will be a part of mobility to stay.”
Gildo Pastor, owner of Monaco-based Venturi Automobiles, the boutique luxury vehicle manufacturer that provides major sponsorship for the Buckeye Bullet, says he has been involved in auto racing for 35 years; he now has a team in the FIA Formula E series, a fully electric race series, with a powertrain based on the Venturi Buckeye Bullet 3.
“I had plenty of fuel cars,” says Pastor, himself a former race car driver, “and about 20 years ago I had a revelation that the electric car is the future.”
Pastor says he has been impressed with the Buckeye Bullet team ever since he first became involved 10 years ago.
“They have incredible knowledge,” Pastor says, “and that is why it is worth doing the deal with CAR and Ohio State. Giorgio (Rizzoni) is a master in speed records. We have the pleasure to work with them.”
By Joan Slattery Wall, Editor, The Ohio State University Office of Energy and Environment
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- Weight: 7,900 lbs
- Length: 38 feet
- Electric power: 3,000 horsepower from a 4-wheel-drive system. Power is supplied by lithium ion batteries, which weigh 3,400 lbs, capable of producing more than 2 megawatts.
- Acceleration: 0-150 mph in 20 seconds
- Tail number: 6941, the atomic weight of lithium.
- The Bullet carries three parachutes to aid in slowing and stopping; an aircraft braking system (from a regional jet) is available for use in case of an emergency.
- 3,000 channels of sensor data on 16 independent networks — including battery voltage and break pressure — on the Bullet are automatically monitored and sent to a computer, generating a 20-page report for team members to analyze and make control adjustments between runs.
- The salt on the Flats absorbs radio waves; repeaters have been installed in mountains in the area to assist with communications during the runs.
- Driver cell: A modified carbon fiber tub from a car that raced in the Indy 500.
- Drivetrain: 4-wheel drive, independent axle drives made up of 4 total motors.
- Turning radius: 200 yards
- Rotational forces cause the tires to grow nearly 2 inches in diameter during the run; the Bullet has never had a tire blowout.
- The team uses chilled oil and ice water to cool the motors and inverters during runs, and bypass chillers cool the hardware between runs.