HONDA Insight - Manual (Page 65)

65
DC-DC C
ONVERTER
The Insight engine is not equipped with an
ACG (AC Generator or Alternator). Instead,
recharging of the 12V battery and powering of
the conventional 12V electrical system is
performed by a DC-DC converter located in the
IPU compartment.
Elimination of the conventional Alternator
reduces engine load, leading to better fuel
efficiency. Another advantage is that by
supplying power to the 12V electrical system
from the IMA battery, electrical system voltages
remain very constant, even under changing
electrical system loads. Even during idle stop and
restart, headlight brightness, wiper speed, etc.
remain constant.
Power is supplied to the DC-DC converter
from the IMA Motor/Generator though the MDM, or by the NiMH Battery Module. This power has to be
reduced to 12V to charge the Insight's 12V battery and to support the conventional 12V electrical system. It
is the DC-DC converter that performs this task. It transforms 144V DC as an input source into 12V DC
output power.
The 144V Direct Current supplied from the IMA Motor or Battery Module is first converted into high
voltage Alternating Current, which is then stepped down by a transformer to low voltage AC before
being converted back to DC for use by the Insight's 12V electrical system.
The DC-DC converter is a high voltage component, and produces substantial heat during operation. To
ensure proper cooling of the DC-DC converter, it is mounted to a finned aluminum heat sink fitted inside a
magnesium housing. The PGM-FI ECM controls the output of the DC-DC converter according to power
consumption of the 12V electrical system.
The MCM may stop DC-DC converter operation if certain IMA malfunctions occur, or if the DC-DC
converter's temperature rises abnormally. Any time that the DC-DC converter is not functioning normally,
the charge indicator lamp on the instrument panel will be illuminated.