Toyota COMPUTER-CONTROLLED SYSTEM Training Manual page 135

OTHER CONTROL SYSTEMS - Turbocharging Pressure Control Syste m
TURBOCHARGING PRESSURE CONTROL SYSTEM
The Engine ECU turns the VSV on and off* to This maximizes engine performance and
control the turbocharging pressure in accordance maintains engine durability, as well as
with the type of gasoline being used (regular or suppressing knocking under all engine running
premium), the coolant temperature, intake air conditions, including warm-up, irrespective of
temperature, intake air volume, and engine the gasoline octane rating .
speed . The VSV is controlled with the duty ratio in
some models .
Turbocharge r
OPERATIO N
The VSV is turned on by the ECU to increase the The VSV does not turn on unless all of the abov e
turbocharging pressure when the fuel is judged
to be premium by the fuel octane judgment
function (See page 116), and when the coolant
temperature and intake air temperature are
within a predetermined temperature, and the
intake air volume is above a predetermined
level .
conditions are met, even when premium
gasoline is used .
REFERENCE
For a detailed explanation of the construction
and operation of the turbocharger, see Step 3,
l . . 2 (Turbocharger and Supercharger) . vo
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