This year brought many new challenges to the Kettering University Formula SAE team. Since the team’s previous chief engineer had left and other core members had graduated, members knew that it was going to be an uphill battle coming into this competition season.
Additional challenges arose when the team decided to switch to ten-in wheels from the old, heavy thirteens that GMI2014’s predecessors wore (GMI is a reference to General Motors Institute, the former name of Kettering University). With new members coming aboard and a redesign of key parts such as the chassis, uprights, suspension, and brakes, this year tested not only the team’s engineering skills, but also its patience.
A Kettering strength
After completing GMI2014 and having a few days to test it, the story of the Kettering University Formula SAE team’s competition at Michigan International Speedway (MIS) began. Arriving at MIS on Thursday (May 15) morning, sleep-deprived and teeth-stained from coffee, team members quickly got ready for the static events while preparing to go through technical inspection. The first event for the team was the cost event. There, the judges looked over the team’s car and picked over things that were not in the cost report—things that otherwise would have gone unnoticed. Walking away from the audit, the team placed the highest in any event that it would at MIS with a respectable sixth place.
The next stop for the team was the design event. Having an all-new design with very few days of testing meant that the theoretical data was there, but there was hardly any test data. Despite lacking the test data of a new design, the team came out 38th overall, tying with some other teams.
The last static event on tap for the team was the business presentation. After finishing 52nd in the event last year, the 2014 Kettering team business presenters were able to pitch the team to 12th place for the event, an improvement of 40 places. Placing quite well in the static events, it was clear that the Kettering University Formula SAE team was unable to be stopped…or so it seemed.
Problems with Percy
During the mandatory technical inspection, the team had a hard time getting Percy (the name of the template representing a person sitting in a Formula SAE vehicle) to fit comfortably in the car. Unfortunately, by the time the team passed tech inspection on Friday, the acceleration and skid pad events had come to a close. But the team was able to get the car through the tilt, noise, and brake tests, and was able to compete in the autocross event held that afternoon.
Managing to do well enough in the autocross event to land the team’s car in the 33rd spot for the endurance event to be held the next day allowed members of the team to sleep comfortably Friday night.
But the next day was full of surprises.
Saturday brought the highest-weighted event: endurance. While this year’s endurance event at MIS had some surprising occurrences such as three car fires and less than half of the field finishing the event, the Kettering University Formula SAE team’s car came out in full force. Unfortunately, a little over halfway through the team’s swing at endurance, the car ran out of gas. This was puzzling because the Kettering team’s car won fuel economy last year. The team bounced into action getting the car back into the paddocks so that the problem could be diagnosed.
The good news
What may have turned out to be a problematic issue turned out to be a simple one.
“The main issue with the vehicle at Michigan [International Speedway] was an issue with the ECU code,” commented the Kettering University Formula SAE team chief engineer Adam Watson. For the 2014 season, it was decided to use a new adaptive O2 sensor. This allows the fuel map to continuously update to refine itself based on the feedback from the O2 sensor. While this would normally be a positive change to the vehicle, removing the O2 sensor and turning off the adaptive O2 instead of just disabling the adaptive O2 can cause the fuel map to continuously adapt to a fixed feedback value, which is incorrect.
That is, unfortunately, what the Kettering University Formula SAE team did. Without disabling the adaptive O2, the ECU kept injecting more and more fuel into the combustion chamber every lap until the car ran out of fuel. At the time that the car did so, it was just over halfway through the endurance event. The car had to be towed off of the course.
After finding out what went wrong, the Kettering team set its focus on the Formula SAE competition in Lincoln, NE. The team also made some adjustments to its vehicle.
“For Lincoln, we tested many combinations of camber, toe, springs, and roll center to tune the chassis for the different dynamic events,” explained Watson.
By testing the different combinations, the team nailed the different vehicle setups needed for the dynamic events. The team also gave the car more curb appeal by powder-coating the chassis white. This required the car to be disassembled before powder coating and then reassembled. In addition, more data was acquired during the time between the two competitions for the static events, especially for the design event, through more testing.
Despite not having a stellar performance at MIS like it did last year, it was evident that the Kettering University Formula SAE team brought some lessons home to learn from. Still, finishing 62nd overall with one of the lowest-priced cars at the competition is nothing to be upset about and proves that the lowest-priced car is certainly not the worst car. That is especially so considering that most of the parts of the car were completely redesigned and the car was partially built by new team members.
What the Kettering team learned at MIS was used as a basis for preparing the car for the Lincoln competition, where the team took 1st in fuel efficiency, 2nd in cost, 11th in endurance and, along with winning Nucor Steel’s Pay for Performance Award for the second year in a row, 10th overall.
To keep up to date with the Kettering University Formula SAE team, like its Facebook page: https://www.facebook.com/KetteringFSAE.
Charles Mancino, a junior studying mechanical engineering at Kettering University, wrote this article for MOMENTUM. He has been on the Kettering University Formula SAE team since his freshman year and has been an instrumental part in designing and building the university's Formula SAE vehicles. He is also the vice president of the Kettering University A-Section Firebirds Club, a member of the Kettering University student-run newspaper, a tour guide at Kettering University, and a blog writer for the university.Continue reading »