MOTOR & Differential
In converting an internal combustion vehicle to an electric one, we first decided to use an Enstroj Emrax 208 motor similar to the Emrax 207 used by Penn Electric Racing. Given the similarity of our designs, we used the weight and top speed from Penn Electric Racing's 2016-2017 REV3 car to calculate the gear ratio for our EV.
EMRAX 208 MOTOR
EMRAX 208 SPEC TABLE
CALCULATING GEAR RATIO
ACCUMULATOR
The accumulator is a container that houses the batteries and the high and low voltage systems. The accumulator serves as a life support system for the batteries, insulating and protecting them, managing their output through the Battery Management System (BMS), and cooling them and their associated systems with three 130 CFM fans that induce airflow.
The Lithium-Ion batteries are arranged asymmetrically in five segments, four segments with 15 batteries and one segment with 12 batteries, for a total of 72 batteries. The asymmetric arrangement was implemented to maintain a low center of gravity within the narrow chassis, while allowing for the motor and differential to maintain the same powertrain plane used for the internal combustion engine.
ACCUMULATOR INTERNAL COMPONENTS
INDUCED COOLING THROUGH BATTERY CHANNELS
STRUCTURAL ADDITION
In adapting the chassis to accommodate the electric drivetrain, it was essential to replace the structural element provided by the internal combustion engine. We designed a tube structure that both improved the torsional stiffness of the chassis by 20% and in addition provided mounting points for the accumulator, the motor, and the inverter.
