1990 MITSUBISHI ECLIPSE wheel

REAR AXLE- Viscous Coupling Type Limited Slip Differential3-a
DIFFERENTIALROlEAM
The differential uses lower torque bearings and
lower torque oil seals to improve power perform-
ante and fuel consumption.
For faster differential cooling and higher reliability
during high speed operation, a differential carrier
with cooling fins has been adopted.For better serviceability, spacers for adjustment of
final drive gear backlash have been inserted
be-tween the side bearing outer race and gear carrier.
A speed difference responsive type viscous
cou-
pling type limited slip differential which provides
outstandingperformance during operationon a
Side gearPinion gearDifferential coverQ./\Side bearing spaceifferential case
VISCOUS COUPLING TYPE LIMITED SLIP DIFFERENTIALRWEBAAWhile the conventional mechanical type limited slip
differential uses a cam (differential pinion shaft) and
disc equipment
compo.sed of a friction plate, disc
and spring seat in limiting the differential, theviscous coupling type limited slip differential limits
the differential by use of a viscous coupling equip-
ment consisting of outer and inner plates and
silicone oil.
Front wheel
Center differential
’ (viscous coupling)Rear wheel
Limited slip differential
assembly
Front differential, I
TDifferential
Differential limiting section
(viscous coupling)11KmI66
L.-

3-6REAR AXLE - Viscous Coupling Type Limited Slip Differential
Is
Side gear (L.H.)
Side gear (R.H.)1Differential case B
Pinion shaft
Thrust
washer
Viscous cokpling
3r
Side gear U3.H.)Differential case
B
, ,,Differential cover
I
‘Gear cagierPir
,Drive pinionfront bearing
Driv& pinionDrive gear
Bearing caprear bearing
ICokpanion flangellAo337
Normal operating range
Hump region
Difference in rotating speed between
right and left wheels (rpm)
RemarkslA hump occurs when there is a large differencein rotatinwheels..!speed between the right and leftlnce the large difference causes
violent shearing of the silicone oil in the
viscous couplin7.by the plates, the oil tempera-
ture rises (the SI Icone 011 expands), and the
torque abruptly rises. If the hump occurs, the
inner and outer plates enter a directly coupled(differential locked) state.llAOO5r
FUNCTIONS AND FEATURES(1) The viscous coupling type limited-slip differential
is functionally the same as
the conventional
mechanical type which reduces slipping of the
rear wheels for better performance when travel-
ing on a rough road or when getting out of a
snowy or muddy surface.
(2) The viscous coupling type limited slip differential
responds to a difference in rotating speed and
has outstanding characteristics for use in an
on-road
4WD vehicle, as it has no difference in
characteristics in the normal operating range
between when power is ON and when it is OFF,
and provides better straight ahead stability and
running performance.
(3) When a single wheel is slipping, a hump could
cause the differential to approach a locked state.
Provision is therefore made to provide a better
ability to get out even in cases of one in a million
such as a stuck state.

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3-8REAR AXLE - Viscous Coupling Type Limited Slip Differential
OPERATIONDrive force smaller
I(Slipping side)Drive force larger(Grippina side)
Rear drive shaft
(L.H.1 (Left wheel)
resistance smaller)Rear drive shaft
(R.H.1 (Right wheel)
11 PO071If a difference in rotating speed occurs between the
right and left wheels, the viscous coupling case @
and viscous coupling hub @ relatively rotate with
the same difference in rotating speed as the rear
drive shafts. As a result a differential limiting torque
is generated by the shear resistance of silicone oil
and helps suppress the differential (slipping).For example, assume that the right wheel rotates at
20 rpm due to the road surface resistance, whereas
the left wheel rotates at 30 rpm. The difference in
rotating speed between the right and left wheels is
10 rpm. Since the viscous coupling is provided
between the right and left wheels, a differential
limiting torque compensating for the difference of
10 rpm in rotating speed is transmitted from the left
wheel to the right one.
Therefore, a larger drive force is transmitted to the
right wheel rotating at the lower speed.

5-4
Braki disc 14A0531
Section A-A
14AO530
,ad Shim
014A0532

Disc wheel
.

5-6BRAKES - Service Brakes
In addition, disc removal and installation is made
easy by the outer disc system, in which the brakedisc and the disc wheel are installed to the hub
bvthe hub nuts.
Brake disc installation cross-section<2WD>
<4WD>
Hub nuts
Brake disc14AO390Hubnuts
Brake&c
14AO622

PARKING BRAKE
BRAKES- Parking Brake5-7
ROSDMBThe parking brake is of the mechanical rear wheel
braking type.The parking brake
cable is of the V-type and is
The parking brake is offset toward the driver’s seataccessible for adjustment through the service hole
provided in the floor console.
from the vehicle centerline for greater ease of
operation.CONSTRUCTION DIAGRAM
Y14AO391
<4WD>14A0626

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14-24FUEL SYSTEM - Sensors
POWER STEERING OIL PRESSURE SWITCHEngine control unit
Power steering oil
pressure switchBattery
voltage
6FUO5OtIWhen the steering wheel is turned and the oil
pressure of the power steering oil pump increases,
the power steering oifpressure switch sends an ON
signal to the engine control unit. The engine control
unit detects the oil pump load with this signal andactivates the idle speed control servo to control
theidle speed. Specifically, it prevents the idle
speecfrom dropping due to oil pump load, thus
ensuringstable engine idling.IGNITION
SWITCH
1IBattery
Ignition
switch
Starter motor
aS terminalcontrol unit
6FUO762The signal indicating that the ignition switch is ON,
OFF or cranking (ST) is input to the engine control
unit.
When the ignition switch ON signal is input to the
engine control unit, the unit energizes the control
relay coil to supply power to the sensors and
actuators.When the ignition switch ST signal is input to the
engine control unit, it determines that the engine
iscranking and controls the fuel injection rate,
despeed control servo, ignition timing, etc. for
-mum cranking conditions.

14-50FUEL SYSTEM- Idle Speed Control
SDeed adiustina screwI -Throttle valve
Lw-3O(-22) 0132) 30(86! 601140) 9ofl94)Coolant temperature
“C (OF)6FUO641
E94
72--2--I
Q--.-.-z
3201.000 --4-\-\
5P9.o%IIIaI L-2O(-41 Of3214Of104)801176)Coolant temperature
“C VF)6FU028E
-201-4) Of3214OI104180(176(2) When the engine coolant temperature is low, the fast idle
air valve together with the idle speed control
servoperated to supply an adequate volume of bypass
,.raccording to the engine coolant temperature.
Feedback Control at
Idle(1) Basic target idle speed
The basic target idle’ speed is preset as a map value
optimized according to the engine coolant temperature.
This speed is maintained to ensure stabilized idle speed.
(2) Idle speed while the air conditioner is being operated
When the engine coolant temperature is high with the air
conditioner switch in the ON position, the idle speed is set
higher than the basic idle speed.
,
ICoolant temperature “C VF)6FUO28:Position Control
When the steering wheel is turned or the air
conditioner switch is operated while idling, theachieve the target position, thus controlling the
engine load changes and consequently the idlebypass air volume and suppressing engine speed
changes. The engine control unit also activates the
speed changes sharply. Therefore, immediately
after detection of such a load signal, the engine
control unit activates the idle speed control servo toidle speed control servo to achieve the optimum
target position while cranking, driving and decelerat-
ing, according to the operating conditions.
Power steering oil
pressure switchIInhibitor
switch
IDash pot
concjition“D”
xl
rangeposition-
UP W-U
IAlPower
steeringposition-
UP.4~i~hnditioner
IIdle speed
control servor”--““IiiI
I
c
IEngine
I
I
1wuosu
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