Mitsubishi Lancer Evolution-VII Workshop Manual page 57

2-12
ACTIVE CENTER DIFFERENTIAL (ACD) AND ACTIVE YAW
CONTROL (AYC)
The LANCER EVOLUTION-VII adopts the newly developed active center differential (ACD).
The driving performance of the ACD has been improved by varying the center differential drive by electronic
control.
The yaw moment is directly controlled by the active yaw control (AYC) adopted from EVOLUTION-V
onwards to improve the turning performance.
By combining and integratedly controlling these two systems, the driving performance has been further
improved.
ACD
ACD and AYC
OUTLINE OF CONTROL
The following effects are obtained by equipping the ACD or ACD and AYC.
State of vehicle ACD
1. During de- Similar to the direct engagement
celeration 4WD by increasing the center
(Before differential during sharp decelera-
corners) tion to improve stability in decelera-
tion.
2. First half of The center differential restriction is
turning reduced according to the steering
(Corner en- angle and operation speed to set
trance) the center differential as close as
possible to the free state and
improve turning performance.
3. Latter half The center differential restriction is
of turning enhanced according to the amount
(Corner the acceleration is stepped to set
exit) similar effects as the direct engage-
ment 4WD and improve the accel-
eration performance.
AYC: Turning
1. During deceleration
AYC: Tack in deceleration
(During deceleration when turning)
POWER TRAIN - ACD and AYC
2. First half of turning
ACD: Free
ACD: Direct
engagement
RS, RS II
Option
Option
AYC
[When decelerated during
turning]
The driving power is moved to
the inside turning wheel to
reduce the tack in.
The driving power is moved to
the outside turning wheel
according to the steering
angle and operation speed to
improve the turning perfor-
mance.
The driving power is moved to
the outside turning wheel
according to the amount the
acceleration is stepped to
decrease the acceleration
understeer and improve turn-
ing performance.
3. Latter half of turning
AYC: Under steer deceleration
ACD: Direct engagement
Integrated control effects
Stability against various
external influences such as
poor road conditions and
driver operations have been
improved.
The response to steering
operations (brisk move-
ment) is improved as much
as possible.
Two elements (acceleration
and turning) have been
improved simultaneously.