Fuel Injection Timing Control; Ouline; Main And Pilot Injection Timing Control - Denso 4D56 Service Manual

Operation Section
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11. FUEL INJECTION TIMING CONTROL

11.1 Ouline

Fuel injection timing is controlled by varying the timing in which current is applied to the injectors.

11.2 Main and Pilot Injection Timing Control

(1) Main Injection Timing
• The engine ECU calculates the basic injection timing based on the engine speed and the final injection quantity, and adds various types
of corrections in order to determine the optimal main injection timing.
(2) Pilot Injection Timing (Pilot Interval)
• Pilot injection timing is controlled by adding a pilot interval to the main injection timing. The pilot interval is calculated based on the
final injection quantity, engine speed, coolant temperature, ambient temperature, and atmospheric pressure (map correction). The pilot
interval at the time the engine is started is calculated from the coolant temperature and engine speed.
Pilot Injection
Interval
Top Dead Center (TDC)
Main Injection
QB0723E