Isuzu 4HK-1, Руководство пользователя, Страница: 12 / 50

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Isuzu 4HK-1 and 6HK-1 Engine Overview (continued)
Outputs from 40 pin engine harness connector: (continued)
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The injectors are controlled by the engine control module (ECM). The ECM sends a
common power supply to injectors 1, 3 and 5. The ECM also sends a common
power supply to injectors 2, 4 and 6. The ECM fires the injectors by controlling the
ground of the individual injectors. The ECM calculates the basic injection amount
and timing based on the signals from throttle position sensor, boost pressure sensor,
crankshaft (CKP) sensor, camshaft (CMP) sensor, etc. The timing of the injection is
controlled by when the injector activates. The fuel quantity delivered is based upon
the amount of time that the injector is open and also the pressure supplied by the
common rail. To improve combustion in cylinders, the system injects a little fuel (pre-
injection or pilot injection) and ignites it at the beginning of the cycle. A second
injection (main injection) delivers the fuel required deliver the horsepower needed.