Isuzu 2008MY N Series, Руководство по ремонту

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Engine Control System (4HK1) 1A-393
The position of the turbocharger nozzle is controlled by
the variable nozzle turbocharger (VNT) control module
based on the command from the ECM. The VNT
control module controls a drive signal to the
turbocharger nozzle control solenoid that installed to
the turbocharger assembly by utilizing position sensor
inputs to control the turbocharger nozzles. When the
engine is not under load, the turbocharger nozzles are
in an open position (A), or no boost condition. When
the engine is under load, the VNT control module
commands the control solenoid to close the
turbocharger nozzles (B), thus increasing the boost.
The ECM will vary the boost dependant upon the load
requirements of the engine.
The charge air cooler also helps the performance of the
diesel. Intake air is drawn through the air cleaner and
into the turbocharger compressor housing. Pressurized
air from the turbocharger then flows forward through
the charge air cooler located in the front of the radiator.
From the charge air cooler, the air flows back into the
intake manifold.
The charge air cooler is a heat exchanger that uses air
flow to dissipate hear from the intake air. As the
turbocharger increases air pressure, the air
temperature increases. Lowering the intake air
temperature increases the engine efficiency and power
by packing more air molecules into the same space.
LG4HKED-WE-0871.book 393 ページ ２００７年１１月２９日 木曜日 午後６時２９分