Continuously Variable Transmission

Continuously variable transmission block diagram

Role of subsystem in vehicle
The ‘cvt’ accepts torque from the clutch or other upstream device, and transmits it to the final drive after overcoming its own losses and increasing the torque by the current pulley ratio.

Description of modeling approach
The CVT block interacts with the CVT controller, which determines the current pulley ratio. The CVT then uses this pulley ratio to estimate input torque and speed, and in turn uses these along with a lookup table to compute CVT efficiency. The efficiency is used to compute torque losses as measured on the input side, and the torque required to overcome the CVT’s inertia is also taken from the input side. The above order of calculation applies to the ‘request’ data branch. For the ‘available/actual’ data branch, the pulley ratio and efficiency computed in the ‘request’ branch are used to perform the necessary torque multiplication and speed reduction.

Variables used in subsystem

See Appendix A.2: Input Variables
See Appendix A.3: Output Variables

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