Vehicle Parameters

This section references the vehicle parameters used to set the speed/Revolution Per Minute (RPM) ratio.

Note: In Car Sound Simulator, Partials data depends on RPM and noise data depends on vehicle speed. Therefore, a ratio coefficient is needed to convert RPM to speed.

The Vehicle Parameters tool helps to find a coefficient C allowing to convert RPM in rev./min into speed in km/h. The formula is speed = C* RPM. This coefficient is needed in Car Sound Simulator to generate the aerodynamic and rolling noises of the vehicle. Indeed, engine sound is controlled by RPM, while aerodynamic and rolling noises are controlled by the speed of the vehicle.


Parameter	Description
Transmission gear Ratio	The ratio is the number of teeth on the driven gear (ring) divided by the number of the teeth on the drive gear (pinion). For example, a 4.5 ratio means the drive gear turns 4.5 times to make the driven gear turns once.
Differential gear ratio	Differential can drive the rear wheel at different speed.
Tire radius	Circumference of the tire.
Resulting coefficient	Coefficient C allowing to convert RPM into speed.
Example	Option to test the coefficient for a given RPM. If the parameters of the car are not known, use the Example box to adjust the parameters so that the speed is close or similar to the real speed of the vehicle for a given RPM you know.