Success is in The Design Scheduling

In correspondence with the team, U of Laval team manager, Bruno Désaulniers spoke of their success.

He noted that “one of the biggest challenges we have every year is finishing all the projects … on time to ensure the car will be completed for the competition.”

 “To ensure that every project is done on time,” he added, “we set a tight schedule and all the sub-teams must respect it.”

These scheduling challenges that U of Laval faces don’t seem that different from the major car manufacturers that also face yearly release cycles. However, within that time both U of Laval and major manufacturers get a lot done.

“There was a significant decrease in the energy loss due to the clutch. Also, the electronic system and the fuel line were more reliable than the previous year’s,” Désaulniers said. “We also changed the rear sprocket to get a better ratio between the engine and the rear wheel.”

Last year, U of Laval’s team had a top mileage around 1145 mpg. Désaulniers explained this was not representative of the car’s potential due to an over-voltage of the fuel-pump control board. This error forced the team to improvise a solution during last year’s competition.

He explained that electrical improvements, a redesign of the fuel line, and an improved compression ratio were responsible for the team almost doubling its fuel mileage this year. “We were confident we could get a pretty good score,” Désaulniers said. “We got some difficulty with the electronic system, but we were able to fit it in time to score our top run of 2098 mpg.”

U of Laval wasn’t the only team to experience a wide range of mileage results. This year’s competition saw 23 teams from the U.S. and Canada compete for the win at the Eaton’s Proving Grounds in Marshal, Michigan. Much of these teams achieved a mileage of at least 200 MPG. However, the Top 10 ranged from U of Laval’s 2098 mpg to Rowan University’s 423 mpg. Even the top three teams saw a large spread of more than 1000 mpg between their results. The Top 10 teams have been listed below.

Success is Also in the Simulations and Design Iterations

“One of our main goals is to reduce the vehicle weight,” Désaulniers said. “The fact we reuse the shell from last year gives us time to optimize other parts of the car by doing FEA and trying to make them from aluminum. We had been able to reduce the total weight by approximately 2-3 lb.”

The car’s specs, seen below, are quite impressive:

To achieve this reduction of weight, the U Laval team used Siemens NX simulation software. This allowed them to modify the designs to minimal weights without risking failures.

“The advantage with NX is that the whole design process is embedded in a single software,” said U Laval team member Xavier Garant. “This means that when we are in the process of designing a new part, we can switch back and forth between modeling and finite element analysis to make adjustments. This simplifies the iteration process for us.”

Garant explained that an interesting FEA optimization project they performed this year was the transmission sprocket. “The applied forces were calculated using the maximum output torque from the engine and the transmission ratio,” he said. “The simulation also accounted for slight misalignments of the rear sprocket, to validate the strength should this undesirable situation occur. FEA also enabled us to analyze the trade-off between using aluminum and steel. Aluminum has less weight but is less rigid.”

The team started with a baseline sprocket and discovered an optimization by iterating the number of spokes. In the end, the team produced a custom aluminum sprocket increasing the amount of teeth from 125 to 150 and reducing the weight by 45 percent due to an optimized shape and the use of aluminum.

The U Laval Team has used simulation in the past to achieve success. Four years ago, the team performed CFD aerodynamics and FEA analysis to optimize the aforementioned outer shell. “We achieved a weight reduction of 20 pounds and a 30 percent theoretical decrease in drag coefficient compared to our old shell,” said Garant. It’s no wonder U of Laval decided to keep with the shell this year and focus on other low hanging fruit in the design.

About the SAE Supermileage Competition

Students are challenged to design and build a car using new technologies, materials and their wit. The car must traverse a 9.6 mile track using the least amount of fuel possible. The cars must also transport one person and contain a single cylinder four cycle engine.

“The Supermileage competition helps these students develop practical engineering, team building and leadership skills they can use to succeed in their careers, including making tomorrow’s cars and trucks more fuel efficient,” said Staci Kroonc, president, Eaton Vehicle Group.

Teams are also scored on the design of their vehicles. To that point, Kroon said, “The students are so impressive with their ingenuity and creativity. What they accomplish year after year with this competition is truly amazing.”