Honda ACCORD HYBRID 2005 Service Manual page 694

IMA System
S y s t e m D e s c r i p t i o n ( c o n t ' d )
IMA Torque On-demand Control
Depending on the output torque requirements f r o m the driver, A/T, cruise control, TCS, and A B S , the powertrain control
m o d u l e (PCM) controls the total output of the engine and the IMA motor by controlling the variable cylinder
management (VCM), the electric throttle control system (ETCS), and the IMA system. W i t h this IMA torque on-demand
control, the driving performance and the fuel efficiency are i m p r o v e d .
The PCM controls the output of the engine and the IMA motor in the f o l l o w i n g six methods w i t h the required torque and
the engine speed. Depending on the condition of the engine, IMA system, A/T, HVAC, and other systems, the control
methods are modified.
Idle
Engine S p e e d
Area 1
W h e n m a x i m u m output torque is required, the engine is driven by six cylinders w i t h w i d e open throttle, and the IMA
m o t o r assists the engine to increase torque.
Area 2
At high engine speed except w i d e open throttle and deceleration, the engine is driven by six cylinders w i t h o u t assist
f r o m the IMA motor.
Area 3
W h e n partial output torque is required at low engine speed, the engine is driven by three cylinders and the IMA
motor assists the engine to increase output torque. This control m e t h o d saves fuel c o n s u m p t i o n d u r i n g acceleration.
Area 4
W h e n low output torque is required at l o w engine speed, the engine is driven by three cylinders w i t h o u t assist f r o m
the IMA motor. This control m e t h o d saves fuel c o n s u m p t i o n d u r i n g crusie and light load conditions.
Area 5
During deceleration, the PCM stops the fuel injection to all cylinders, and the IMA motor functions as a
generator to charge the IMA battery. The intake and exhaust valves of the rear bank are deactivated by the VCM
to reduce mechanical friction and increase the energy for charging.
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