You can predict the performance of your own car and see what effect a proposed change
to your car will have without going to the trouble of building and testing by using the
MODEL SOLAR CAR MATHEMATICAL SIMULATION.
The simulator predictions have been within 5% of the actual times recorded on the track.
Using it will enable you to get a feel for the effect of various changes. For predictions to
be relevant to your car, you MUST first test your car and enter its parameters into the
simulator.
How can car performance be improved? Where should effort be expended for the best
results? Before these questions can be answered it is necessary to know where the small
amount of power available is being used.
A convenient way to evaluate power use during a race is by considering energy use. As
energy is the product of power multiplied by time, this approach gives a view of the
“amount” of power used over the race. By considering the breakdown of energy use the
most significant areas are easily identified. The areas that should be considered are Air
Drag, Rolling Resistance, Losses in Transmission and Power used to accelerate the car.
By graphing power used against time for each of these over the course of a race the
energy is easily determined, it is represented by the area under the power versus time
graph.
The TOTAL ENERGY available over the course of a race is easily determined, it is
simply the POWER available from the solar panel multiplied by the race time.
This energy will be used in the following:
Overcoming air drag
Overcoming rolling resistance
Giving the car Kinetic Energy
Losses in motor and transmission
Data from the Mathematical Simulator can be used to calculate some of these energies.
Air Drag:
From the simulator air drag and velocity can be read at 0.1 second intervals. For ease of
calculation take these values at say ½ second intervals, multiply them together to obtain
the power (in Watts) used to overcome air drag. Then plot a graph of power versus time,
the graph clearly shows power usage variation as the race progresses. The energy used in
overcoming the air drag is depicted by the area under the graph ie. Power x Time =
Energy (Joules)
Rolling Resistance: