Mitsubishi Fuso CANTER FE85DE6SLGP, Shop Manual

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17E
17E-5
2.2 Exhaust gas recirculation
(1) Exhaust gas recirculation valve control function
•
In accordance with data from sensors, the engine electronic control unit determines the exhaust gas recirculation
valve opening that suits the operating condition and sends a control signal (this indicates the target exhaust gas
recirculation valve opening) to the exhaust gas recirculation electronic drive unit.
When necessary to prevent black smoke emissions and engine speed instability (for example, when the engine is
heavily loaded, when the engine is lightly loaded, and when the exhaust brake is operating), the engine electronic
control unit stops exhaust gas recirculation valve control.
• The exhaust gas recirculation electronic drive unit activates the exhaust gas recirculation valve motor. At the
same time, it monitors the extent of valve lift using a position sensor and sends this information (this indicates the
actual exhaust gas recirculation valve opening) to the engine electronic control unit.
This operation makes it possible for the target exhaust gas recirculation valve opening indicated by the engine
electronic control unit to be precisely maintained.
(1.1) Exhaust gas recirculation valve
•
DC motor in the exhaust gas recirculation valve is driven by con-
trol signals from the exhaust gas recirculation electronic drive
unit. Via a rod, the motor’s operation opens and closes the
valve.
(2) Intake throttle control function
•
When the engine electronic control unit determines from sensor data on the engine speed and engine loading that
the vacuum pressure in the intake manifold is low, it increases the amount of exhaust emissions introduced into
the intake manifold by determining an appropriate butterfly valve opening and by sending corresponding control
signals (these indicate the target throttle opening) to the throttle electronic drive unit.
• The throttle electronic drive unit activates the valve motor. At the same time, it monitors the valve opening using a
position sensor and sends this information (this indicates the actual throttle opening) to the engine electronic con-
trol unit.
This operation makes it possible for the target throttle opening indicated by the engine electronic control unit to be
precisely maintained.