Torque Converter Clutch (TCC): Notes

Fig 1: Torque Converter Lock-up Clutch

Courtesy of DAIMLERCHRYSLER CORP.

In a standard torque converter, the impeller (2) and turbine (1) are rotating at about the same speed and the stator (3) is freewheeling, providing no torque multiplication. By applying the turbine's piston and friction material (9), a total converter engagement can be obtained. The result of this engagement is a direct 1:1 mechanical link between the engine and the transmission. See Fig 1.

The clutch can be engaged in second, third, fourth, and fifth gear ranges.

The TCM controls the torque converter by way of internal logic software. The programming of the software provides the TCM with control over the torque converter solenoid. There are four output logic states that can be applied as follows:

1. No EMCC
2. Partial EMCC
3. Full EMCC
4. Gradual-to-no EMCC