Every week, a group of UC Davis mechanical and electrical engineering majors gather in Bainer Hall. There, they integrate knowledge from electrical circuits, dynamics, material properties and many other engineering disciplines. Their goal? To build the fastest electric racecar they can under the guidelines of the Society of Automotive Engineers’ (SAE) Formula Electric competition.
You might know them as the former Formula Hybrid team. This year, they have switched focus to electrical vehicles. According to several Formula Electric members, electric vehicles are the way of the future.
“You can do more with a bigger electric motor. With a hybrid, you are constrained by the chassis and how much power you can put out,” said Jeff Bouchard, a fourth-year electrical engineering major.
The general overview of how electric vehicles work starts with the motor. The motor turns electrical energy into mechanical energy, propelling the vehicle into motion. The motor receives commands from a computer called the motor controller. A person may input different commands to the motor controller, such as throttling. The battery supplies energy to the entire car.
Formula Electric’s racecar consists mainly of the chassis (the frame) and the power train (motor and motor controller), which is also a senior design project for some members. The work is divided among teams. The chassis team cuts and reshapes steel tubes for the frame, the electrical team does the circuitry and programming for the actual controls and the ergonomics people work on steering, seats, the acceleration pedal, brake pedal and gas pedal.
“[There are] a lot of different parts, there [are] different deadlines. We’re aiming for finishing in March, since our competition is in June,” said Kimberley Carr, a third-year mechanical engineering major.
Formula Electric is using a motor from Zero Motorcycles, an electric motorcycle company based in Santa Cruz. In January 2012, Pike’s Research, a market research and consulting firm, ranked Zero Motorcycles the highest among electric motorcycle manufacturers.
“Battery technology is now getting to a point where it is really viable. The more you can put into this new battery technology, the better performance you can expect from them. You cannot just fit more, you can fit better,” Bouchard said.
Even among electric vehicles, UC Davis Formula Electric’s car is trying innovative technology. A new direction with electric vehicles that has taken the spotlight is torque vectoring. A traditional electric car like a Tesla uses one giant battery with one giant motor that goes all to the back wheels. In the Formula Electric car, there are two motors for each of the back wheels.
“There’s [also] a sensor network and a control module on our car, which determines what the sensors are telling, and this is what should be done with the motors,” said Lucas Bolster, a fourth-year mechanical engineering student.
The sensors look at dynamic data such as wheel speed, tire temperature, shock displacement, steering angle and throttle and brake position. The control module takes that data and dynamically allocates power to each wheel. The varied allocation of power increases efficiency so the car can get through corners with high speed while using less energy. Currently, they project that the car can go 0-60 mph in about three seconds. The top speed is expected to be around 70-90 mph, but according to Bouchard, the team is focusing more on acceleration than top-speed. The driver will likely be a member of the team.
“I think it’s pretty cool to work on the racecar. There’s always room to apply what you learn in class to what you do physically. There’s application like in ENG 104, you learn all about stresses and strain and heat deformation. You have to think about when you’re welding. Maybe you’re good at test taking, but you need to be able to retain the knowledge in a way that you can practically apply it,” Carr said.