Honda ACCORD HYBRID 2005 Service Manual page 859

S y s t e m D e s c r i p t i o n
General Operation
The automatic transmission is a c o m b i n a t i o n of a 3-element torque converter and four-shaft electronically controlled
unit w h i c h provides 5 speeds and 1 reverse. The entire unit is positioned in line w i t h the engine.
Torque Converter, Shafts, Gears, and Clutches
The torque converter consists of a p u m p , turbine, and stator assembly in a single unit. The converter housing (pump)
is connected to the IMA motor rotor t h r o u g h the drive plate and torque converter supporting hub. The IMA m o t o r rotor
is connected to the end of the engine crankshaft. A r o u n d the outside of the torque converter is a ring gear. W h e n an
IMA motor control system malfunction occurs, the engine doesn't crank w i t h the IMA motor, the ring gear meshes
w i t h the starter pinion and the engine cranks w i t h the starter. The entire torque converter assembly serves as a
f l y w h e e l , t r a n s m i t t i n g power to the transmission mainshaft. The transmission has four parallel shafts: the mainshaft,
the countershaft, the secondary shaft, and the intermediary shaft. The mainshaft includes the 4th and 5th clutches, and
gears for 3rd, 4th, 5th and reverse (reverse gear is integral w i t h the 5th gear). The countershaft includes gears for the
final drive, 2nd, idler, 1st, 4th, 5th, and reverse (the final drive gear is integral w i t h the countershaft). The secondary
shaft includes the 1st, 1st-hold, and 2nd clutches, and gears for park, 2nd, idler, and 1st. The intermediary shaft
includes the 3rd clutch, and gears for 3rd and 4th. The countershaft 5th gear and the countershaft reverse gear can be
locked to the countershaft at its left end, providing 5th gear or reverse, depending w i t h w h i c h w a y the selector is
m o v e d . The gears on the mainshaft, secondary shaft, and intermediary shaft are in constant mesh w i t h those on the
countershaft. W h e n certain conditions of gears in the transmission are engaged by the clutches, power is transmitted
t h r o u g h the mainshaft, and/or to the secondary shaft, intermediary shaft, then to the countershaft to provide drive.
Electronic Control
The electronic control system consists of the powertrain control m o d u l e (PCM), sensors, and seven solenoid valves.
Shifting and lock-up are electronically controlled for comfortable driving under all conditions. The PCM is located
below the dashboard, under the front lower panel behind the center console.
Hydraulic Control
The valve bodies include the main valve body, the regulator valve body, the secondary valve body, and the
accumulator body. The main valve body contains the manual valve, the m o d u l a t o r valve, the shift valve A, the shift
valve B, the shift valve E, the CPC valve A, the servo control valve, the lubrication check valve, the lubrication control
valve, the torque converter check valve, the lock-up t i m i n g valve, the relief valve, the cooler check valve, the lock-up
shift valve, and the ATF p u m p gears. The regulator valve body contains the regulator valve, the lock-up control valve,
the servo valve, and the 3rd accumulator. The secondary valve body contains the shift valve C, the shift valve D, the
CPC valve B, the CPC valve C, the reverse control valve, and the reverse CPC valve. The accumulator body contains the
1st, 1st-hold, 2nd, 4th, and 5th accumulators, shift solenoid valves A, B, C, and D. The auxiliary transmission fluid
p u m p (ATFP) is m o u n t e d on the outside of the torque converter housing. W h e n the vehicle comes to a stop in auto idle
stop, the auxiliary transmission fluid p u m p starts to operate, and supply hydraulic pressure to the regulator valve.
Fluid f r o m the regulator passes t h r o u g h the manual valve to the various control valves. All the clutches receive fluid
f r o m the internal hydraulic circuit.
Shift Control Mechanism
To shift gears, the PCM controls shift solenoid valves A, B, and C, and automatic transmission (A/T) clutch pressure
control solenoid valves A and B, w h i l e receiving input signals f r o m various sensors and switches located t h r o u g h o u t
the vehicle. The shift solenoid valves shift the positions of the shift valves to switch the port to send hydraulic pressure
to the clutches. The A/T clutch pressure control solenoid valves A and B control the CPC valves A and B to shift
s m o o t h l y between lower and higher gear. This pressurizes a line to one of the clutches, engaging the clutch and its
corresponding gear.
(cont'd)
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