Light Duty Technology Cost Analysis, Power - US Environmental ...

The electric pump (Figure D-30 ) is isolation mounted to the front radiator core support.
Coolant lines are attached with two (2) standard spring clamps. Since the system was separate
from the engine cooling system a separate reservoir was employed.
Figure D-30: Auxiliary Coolant Pump with Mount, Hoses, Spring Clamps &
Reservoir
The coolant routing through the hybrid transmission serves two (2) purposes; it cools the
power electronics, and extracts energy from the transmission fluid. The heat exchanger,
partially integrated into the Housing – Electronic Assembly (Figure D-31), provides a
physical boundary between the two (2) main functional sections of the transmission. The
top section – or “electrical section” – houses all the power electronics and controls. The
bottom section – or “mechanical section” – houses the gearing, traction motor, generator,
and other miscellaneous associated hardware.
On the “electrical section” of the transmission, coolant running through the heat
exchanger cools the power electronics mounted to the top side of the heat exchanger.
Thermal conductive paste is used under each component to maximize heat transfer
(Figure D-32).
On the bottom side of the heat exchanger, which is partially integrated into the transaxle
case – main subassembly, transmission fluid is cooled as it flows through the bottom
chamber. Cooled transmission fluid leaving the heat exchanger is then circulated to key
components within the transmission, including the main planetary set, bearings, traction
motor, and generator.
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