Road Load Power

When we want to test engine performance,we can take the part load power level as reference point for testing engines where it is knows as the power required to drive vehicle on a level road at steady state speed.called that power Road load power.

Road load power overcomes the rolling resistance which
arises from the friction of the tires and the aerodynamics drag
of the vehicle.

Rolling resistance " sometimes known as Friction Drag "
CR ,and Aerodynamic drag " some times known as Pressure
Drag Cd , when the two paramater known the road load power
Pr from the empirically formule

Pr = [ CR Mv g + 1/2 D Cd Av Sv ] SV

CR                        Coefficient of rolling resistance

Mv                    Mass of vehicle

g                      Acceleration due to gravity

D                  Ambient air denisty

Cd                           Drag Coefficient

Av                            Frontal area of vehicle

Sv                     Vehicle   speed