Function Of Torque Converter Lockup Clutch Control

Fig 1: Function Of Torque Converter Lockup Clutch Control

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Operation 

The aim of using the torque converter lockup clutch is to reduce the fuel consumption and exhaust gas emissions of the vehicle by reducing torque converter slip. This stands in contradiction to the ride comfort demands made on the drive train with regard to its vibration behavior. The task of the electronic transmission control is therefore to close the clutch in all driving situations relevant to fuel consumption, if possible, and ensure that the engine vibrations are isolated from the drive train.

The characteristic curves shown in the diagram illustrate the different operating states of the torque converter lockup clutch in relation to the accelerator pedal position and transmission output speed, plotted for one transmission gear.

In addition to the evaluation of these characteristics, the status of the torque converter lockup clutch is also determined by other variables.

Variables influencing the states of the torque converter lockup clutch:

• Accelerator pedal movement.
• Uphill and down hill gradients.
• Transmission shift functions.
• ATF temperature.
• Durability requirements.
• Load condition.
• Engine control influences.

1. Torque Converter Lockup Clutch Control Pressure, Function
   
   See TORQUE CONVERTER LOCKUP CLUTCH CONTROL PRESSURE, FUNCTION  .