Ravigneaux Four-Speed Transmission

This model shows a test harness for a Ravigneaux 4-speed transmission. The subsystem uses the Ravigneaux Gear block and five friction clutches to implement four forward ratios plus reverse. Meshing losses are enabled in the Ravigneaux gear. The clutch states required to implement the different ratios can be viewed by opening the Clutch Schedule block.

The test executed in this model drives the input shaft to the transmission at a constant speed while cycling through all gears, including neutral. The shaft speeds and power are measured so that the gear ratios and overall efficiency can be calculated.

Model

Clutch Schedule Subsystem

Transmission Subsystem

Simulation Results from Simscape Logging

The plot below shows shaft speeds and overall transmission efficiency as the transmission is cycled through each of its gears. The input shaft is turned at a constant speed. The table in the lower right shows the steady-state values for gear ratio and efficiency for each gear.