Operating Principles

OPERATING PRINCIPLES
The electronic control system is split into four main functional areas:
- Shift Point Control
- Lock-up Control
- Pressure Modulation
- Engine Torque Control

Shift Point Control
The optimum gear ratio is selected as a function of transmission output speed, engine load, position of selector switch and program switch.

Lock-up Control
The torque converter clutch is engaged as a function of load, output speed, gear selected and drive program. Lock-up is possible in second, third and fourth gear. Apply and release quality is controlled by the pulse width modulated pressure regulator solenoid.

Pressure Modulation
Hydraulic pressure in the transmission shift friction elements is accurately matched to transmission output torque using an electrically operated solenoid valve to control pressure level. Transmission input torque is calculated from an output torque value, supplied by EMS, and converter slip.

Engine Torque Control
Engine torque control reduces the energy dissipated within the system during gear shifts. The effect of this control increase the transmission service life by reducing slippage time, increases comfort by reducing clutch torque transmission and allows a greater transfer of power by the transmission unit.