1998 HONDA CIVIC circuit

Description
Clutches/Reverse Brake/Planetary Gear/Pulleys
Clulches/Reverse Brake
The CVT uses the hydraulically-actuated clutches and brake to engage or disengage the transmission gears. When
hydraulic pressure is introduced into the clutch drum and the reverse brake piston cavity, the clutch piston and the reverse
brake piston move. This presses the friction djscs and the steel plates together, locking them so they don't slip. Power is
then transmitted through the engaged clutch pack to its hub-mounted gear. and through engaged ring gear to pinion
gears.
Likewise, when the hydraulic pressure is bled from the clutch pack and the reverse brake piston cavity, the piston releases
the friction discs and the steel plates, and they are free to slide past each. This allows the gear to spin independently on its
shaft, transmitting no power.
Start Clutch
The start clutch, which is located at the end of the driven pulley shaft, engages/disengages the secondary drive gear.
The start clutch is supplied hydraulic pressure by its ATF feed pipes within the driven pulley shaft.
Forward Clutch
The forward clutch, which is located at the end of the drive pulley shaft, engages/disengages the sun gear.
The forward clutch is supplied hydraulic pressure by its ATF feed pipe within the drive pulley shaft.
Reverse Brake
The reverse brake, which is located inside the inte.mediate housing around the ring gear, locks the ring gear in E posi-
tion. The reverse brake discs are mounted to the ring gear and the reverse brake plates are mounted to the intermediate
housing. The reverse brake is supplied hydraulic pressure by a circuit connected to the internal hydraulic circuit.
Planetary Gear
The planetary gear consists of a sun gear, a carrier assembly, and a ring gear. The sun gear is connected to the input shaft
with splines. The pinion gears are mounted to the carrier which is mounted to the fo.ward clutch drum. The sun gear
inputs the engine power via the input shaft to the planetary gear, and the carrier outputs the engine power. The ring gear
is only used for switching the rotation direction of the pullev shafts,
In E. E, and E positions (forward range), the pinion gears don't rotate and revolve with the sun gear, so the carrier
rotates. In E] positjon {reverse range), the reverse brake locks the ring gear and the sun gear drives the pinion gears to
rotate. The pinion gears rotate and revolve in the opposite direction from the rotation direction of the sun gear, and the
carrier rotates with pinion gear revolution.
Pulleys
Each pulley consists of a movable face and a fixed face, and the effective pulley .atio changes with engine speed. The
drive pulley and the driven pulley are linked by the steel belt.
To achieve a low pulley ratio, high hydraulic pressure works on the movable face of the driven pulley and reduces the
effective diameter of the drive pulley. and a lower hydraulic pressure works on the movable face of the drive pulley to
eliminate the steel belt slippage. To achieve a high pulley ratio, high hydraulic pressure works on the movable face of the
drive pulley and reduces the eifective diameter of the driven pulley, and a lower hydraulic pressure works on the movable
face of the driven pulley to eliminate the steel belt slippage.
b
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Description
Electronic Control System ('gG - 98 Modelsl (cont'dl
Circuit Diagram and Terminal Locations
GNITIONSWITCN
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SIAiT CLUTCH CONTSOLLINEAFSOLENOID
sHtFT CONmOILINIAftSOLENOID
BFAXELIGHT
PAS|(ING 8MI(E SWITCH
i\c-...............- +B
i\--------.--_ rcr
: MAP(PBIg s61
E rtDiRxo
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scs
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D
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Circuit Diagram and Terminal Locations -'99 - 00 Models
IGN1TIONSWTCHPH.PLCOiTSOLLINEAF SOLEI€ID
SIAFT CLIJICH COTITROLLINEiF SOLET€IO
SHIFI CONTNOTLINEAR SOLEI{OIO
INNIB TOF SOLETIOIO
IGPl
vcc2TPS
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Secondary Valve Body
The secondary valve body contains the PH regulator valve. the clutch reducing valve' the start clutch valve accumulator'
and the shift inhibitor valve
PH Regulator Valve
The pi regulator valve maintains hydraulic pressure supplied from the ATF pump. and supplies PH pressure to the
hvdraulic control circuit and the lubrication circuit. PH pressure is regulated at the PH regulator valve by the PH control
pressure (PHC) from the PH control valve.
Cluteh Reducing Valvo
The clutch reducing valve receives PH pressure from the PH regulator valve and regulates the clutch reducing pressure
(cR). The clutch reducing valve supplies clutch pressure (cR) to the manual valve and the start clutch control valve' and
supplies signal pressure to the PH-PL pressure control valve. the shift control valve, and the inhibitor solenoid valve'
Start Clutch Valv€ Accumulator
The start clutch vatve accumutator stabilizes the hydraulic pressure that is supplied to the start clutch'
Shift Inhibitor Valve
The shift inhibitor valve switches the fluid passage to switch the start clutch control from electronic control to hydraulic
control when the electronic control system is faulty. lt also suppliss clutch reducing pressure (cR) to the pitot regulator
valve and the pitot lubrication pipe.
START CLUTCH VALVE
SECONDARY VALVEBODY
SHIFT INHIBITOE VALVE
(cont'd)
PH REGULATOR VAL
REDUCING VALVE
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Shift Valve BodY
The shift valve body contains the shift valve and the shift control valve. Both are ioined to the shift control linear solenoro.
r tl'ft1il1rf"","" is controred by shift varve pressure (sV) from the shift contror varve. The shift varve distributes pH
pi""aur" "nO PL pressure to drive pulley and the driven pulley' to shift the transmission'
t t*"rilf:::lr';ivarve contrors the shift varve in accordance with the throttre opening and vehicle speed rhe shift
control valve is convorr"o uv ti" "iirt "ontrol linear solenoid, which is controlled by the TcM or PcM When the elec-
tronic control system is faulty, t;; snift controt uutue "witches the shift inhibitor valve to uncover the port leading the
pitot regulator pressure to the start clutch
CONTROL VALVE
VALVE BODY
T;J:"i"""1ff"t""ilody contains the manuar varve and the reverse inhibitor varve. The manuat varve bodv is borted to the
intermediate houslng
. ManualValve
The manual valve mechanicallY uncovers/covers the fluid passage according to the shift lever position'
'
ff:e;;;.'::'?Xftl::T",* is contro ed by the reverse inhibitor pressure (Rl). lt intercepts the hvdraulic circuit to the
reverse brake while the vehicle is moving forward at speeds over approximatelv 6 mph (10 km/h)'
REV€RSE INHIBITORVALVE
MANUAL VALVEBODY
SHIFT CONTROL
MANUAL VALVE
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E position, at middle sPeed range
Asthespeedofthevehic|ereachestheprescribedVa|ue,theshiftcontro||inearsolenoidisactivatedbytheTcMorPcM'
Theshiftcontro||inearso|enorocontroIsttresniftcontroIVa|vetoactivateshiftVa|vepressure(SV)'c|utchreducingpres-
sure (CR) trom the clutch reduclng valve becomes shift valve pressure (SV) at the shift control valve Shift valve pressure
(SV)flowstothe|eft"noottr'"st'ittu"tue.theshiftVa|Vetotherightsideandpositioningitinthemidd|eofitstrave|.The
shift valve covers th" pon ao ",oo nLior".irr" tiHl a ,tr" pulleys, and uncovers the port leading low pressure (PL) to the
pu eys. The drive pu ey and tne oriJen priLy |."""iu" to* pressure (PL). At this time, the pulley ratio is in the middle'
Pressure remains to apply the forward clutch and the start clutch'
NOTE: When used, "|eft" or "right" indicates direction on the hydraulic circuit'
(cont'd)
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Description
Hydraulic Flow (cont'd)
@ position, at high spe6d range
As the speed of the vehicle reaches the prescribed value, the shift control linear sol€noid moves the shift contror vatve toincrease shift valve pressure (SV) at the left end of the shift valve. ttre srrit vatve moves to the right side compared to itsposition at the middle pulley ratio. The shift valve uncovers the port leading high pressure (pxito ttre d.ve puley anduncovers the port leading low pressure (PL) to the driven pulley. The drive pu|ey receives high pressure (pH) and the driv-en pulley receives low pressure (pL). The pulley ratio is high.Pressure remains to apply the forward clutch and the start clutch,
NOTE: When used, "left,, or,,right" indicates direction on the hydraulic circuit.
L
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E position
The flow of fluid up to the drive pulley, the driven pulley' and the clutch reducing valve is the same as in E position The
pulley ratio is low b"car"" tt " o riu",i'prti"vi"""v"" t'igtr pressure.(pH) and the drive pulley receives low pressure {PL).
The manual valve is shifted into the B position, and it uncovers the port that leads reverse brake pressure (RVS) to the
reverse inhibitor valve. The inhibitoi Jenoid turns off by means of the TcM or PcM, and reverse inhibitor pressure (Rl) is
appliedtotherightendofthe,"u",""int,iui.o,u,|ve.Thereverseinhibitorva|vemovestothe|eftside,anduncoversthe
port that leads reverse brake pr"a"ur" tivst,o,he reverse brake. clutch reducing pressure (cR) becomes reverse brake
pressure (RVS) at the manuat *r"-, "nJ tro*" to the reverse brake. The reverse brake is engaged, and it locks the ring
gear.
NOTE: When used, "|eft" or "right" indicates direction on the hydraulic circuit'
(cont'd)
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