The Prius That Shook.. - VFAQ Prius Site

The second prototype was completed in April of that year,
and various departments were running evaluations on the test
track at the Head Office technology division. There was,
however, something wrong as the various cooling
components were not working appropriately. The
performances were much worse than in the previous
prototype which had the three-row layout. Suzaki contacted
Nakajima and asked:
"How much higher is the inverter's temperature than it
should be?"
"Let's see ... about five degrees."
"Five degrees, that much? That's a little tough."
The development of every component, such as the
engine and inverter, was based on test data from the last
prototype. For example, the temperature of the cooling system
was expected, therefore, to be the same as or lower than the
temperature in the last prototype. Engineers in each
department had continued with their development work based
on that assumption. To the engineers in other groups, it was
outrageous that the current inverter's temperature would be
five degrees higher than the previous one.
Suzaki, however, had expected some problems to come up
because key systems, such as the inverter, were continuously
redesigned and renewed. For example, increased engine or
motor performance meant more heat would be created. In
another example, the battery department was able to make a
better battery after it had
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