After over a month of research and exploration of our topic, we have broke ground on our simulation.
Up to this point we have:
- Decided on specifications
- Established a base hardware & software architecture for our EV
- Calculated a required motor size required to meet our specifications
- Calculated a battery size required to run the motor
We had made a few initial decisions so that could begin some calculations. We chose the LA92 drive cycle for beginning considerations, which is characterized as aggressive urban driving and highway mix. We chose this cycle in order to more accurately mimic the driving of a typical commuter in a big city. Also, we have decided that the car should be a 2-door coupe that could still hold up to 4 or 5 passengers if needed. We have further translated these specifications to engineering specifications so that we could do calculations.
- Curb weight, 800 kg
- Gross weight, 1200 kg
- 1 Driver and 4 passengers @ 80 kg/person
- Drag Coefficient, 0.38
- Frontal Area, 2.006 m^2
- Tire Size, 0.5309 m (20.9 in.)
- Rolling Resistance Coefficient, 0.007
- Regenerative braking coefficient, 0.4
The peak power calculated for the LA92 drive cycle with the above considerations is 47.73 kW. To ensure the motor is not overloaded, we chose to take 125% of peak power value. This allows the motor requirement to stay below 75% of the cycle’s running load power. The motor requirement value we have chosen is 60 kW. An average motor power was calculated at 6.5 kW, which was then used to calculate the power used by the battery yielding the result: 27.9 kWh. To meet the 100 mile design criteria, the total battery power required is 38.6 kWh.
Our next step is to develop our simulation for the EV. This will be a full scale physics engine that will simulate all conceivable inputs, to test the efficiency of our EV and design accurate control software.
