Mitsubishi Evolution Terminology

Mitsubishi Evolution Terminology

ACD (Active Center Differential)

The ACD incorporates an electronically controlled hydraulic multi-plate clutch. An ECU optimises clutch cover clamp load for different driving conditions, regulating the differential limiting action between free and locked states.

Effect: The result is improved steering response together with better traction. ACD provides three modes -- Tarmac / Gravel / Snow -- to enable quicker control response for changes in road surface. A single ECU provides integrated management of both ACD and Super AYC components.

Super AYC (Active Yaw Control)

Mitsubishi's Active Yaw Control system uses a torque-transfer mechanism in the rear differential. Under ECU control, the system operates to raise cornering performance by transferring torque between the rear wheels as dictated by driving conditions and so control the yaw moment acting on the car body. In an evolutionary step, switching from the use of a bevel to a planetary gear differential gave Super AYC the ability to transfer almost twice the torque between the rear wheels.

Effect: As well as reducing understeer further, it delivers LSD-level traction. The use of a single ECU to integrally manage Super AYC with the ACD results in a synergism that makes both components operate more effectively than if they were under independent control.

Sport ABS braking

The system ECU uses information from a steering angle sensor that detects steering inputs as well as from lateral G and vehicle speed sensors to apportion pressure to each of the four wheels independently.

Effect: The result is improved steering response under braking. Mitsubishi's Electronic Brake Force Distribution (EBD) system, integral with Sports ABS, optimises allocation of braking force between the front and rear wheels. Increasing the pressure applied to the rear wheels when braking close to the limit, EBD reduces the load on the front wheels to realise better anti-fade performance. The system also compensates for changes in surface and vehicle load conditions to ensure predictable and consistent stopping performance at all times.