Mitsubishi Eclipse. Technical Information Manual (1994) - part 68

 

    A B S  

ACTUATOR

HYDRAULIC UNIT (HU)

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The HU, elastically supported by the shield plate
at the front left of the engine compartment, con-
sists of a motor pump, plunger valve, reservoir
and three solenoid valves.

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The HU, positioned between the brake master
cylinder and each wheel cylinder, is a hydraulic
circuit split into two systems associated with
the normal X pipings when the ABS is inactive.

the wheel cylinder.

When the ABS is active, the motor is operated
by a signal from the ABS-ECU to let the pump
generate a hydraulic pressure required to return

fluid against master cylinder pressure. At the
same time, three solenoid valves are operated
to control the hydraulic pressure that acts on

Solenoi

14x0305

Hydraulic unit

 

Wheel speed sensor

Master cylinder

 

Solenoid valve and select-low valve

Refer to 1991 3000GT Technical Information Manual 

(Pub. No. 

Relay box
Refer to P. 3-33.

MOTOR RELAY
Refer to P. 3-33.

VALVE RELAY

Refer to   3-33.

ABS WARNING LIGHT

Refer to P. 3-33.

DRIVE-CONTROL COMPONENTS   ABS 

ELECTRONIC CONTROL UNIT (ECU)

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The ABS-ECU detects the vehicle speed in

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The ABS-ECU has diagnostic and memory 

terms of a signal from the wheel speed sensor

tions.

to determine the rotating condition of the wheel,

If any failure is found, the fail-safe function is

estimates the skidding condition of the wheel

activated and the ABS warning light will 

on the basis of the predetermined theory, and

nate.

outputs a signal to move the solenoid valve

in the HU in such a way as to prevent locking

the wheel.

BLOCK DIAGRAM

ABS-ECU

 Battery I--

r

-

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Wheel speed
sensors

Sensor
interface
circuit

r

 

 

 

 

 CPU monitor circuit

   Motor, solenoid control, 

monitor circuit

Valve relay

 drive circuit

I

interface circuit

FUNCTION OF INDIVIDUAL CIRCUITS

The function of each circuit is the same as in the

FWD vehicle. (Refer to P. 3-35.)

Motor-relay

V a l v e   r e l a y  

 

   ABS 

EXPLANATION OF ECU CONTROL
Braking Hydraulic Pressure Control
Braking hydraulic pressure control is the same as
in the FWD vehicle. (Refer to P. 3-36.)

 Control

ABS on AWD models controls the front and rear
wheels using select-low and activates the solenoid

wheels are controlled mechanically in select-low

valve on one side, including either of the front

by the select-low valve, there is, as a result, pressure

wheels. Furthermore, since the rear right and left

control of three wheels (either front wheel and the
rear right and left wheels) at a time.

FL wheel

FR wheel

Select-

 

 

 

1

Select-
low

RL wheel

wheel

 Select-low valve

Control Speed

The control speed is the same as in the FWD vehicle.

(Refer to P. 3-36.)

 

   ABS 

Control with G-sensor
Since four wheels are connected in AWD models,

and a high frictional resistance road and makes

the four wheels may decelerate almost in phase.
This tendency is especially strong on a low frictional

resistance road; suspected vehicle speed does not
match actual speed, the road is judged to be a
high frictional resistance road and the ABS control
becomes unreliable. At such a time, the G-sensor
distinguishes* between low frictional resistance road

the ABS control reliable by switching the method

of calculating suspected vehicle speed.

When braking on a low frictional resistance road,
the rate of vehicle deceleration is slow. On the 

other hand, when braking on a high frictional

resistance road, the rate of vehicle deceleration
is fast.

Warning
light

Approx.

1 sec.

Approx.

1 sec.

ABS Warning Light Control

In the following cases the ABS warning light lights up.

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It lights up when trouble in the system is recognized.

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It illuminates in the pattern shown in the figure on the
left when the ignition switch is turned ON, to check the

ABS warning light circuit.