FUEL SUPPLY SYSTEM
Introduction Introduction
This portion of the presentation describes the operation of the EUI Fuel Supply System as used on the 3406E engines in machine applications.
This description includes all components that transmit the fuel from the tank and the primary filter to the injectors and return to the tank.
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FUEL SUPPLY SYSTEM
FUEL SUPPLY SYSTEM
S through the fuel through the fuel supply system
System Fuel Flow System Fuel Flow
Fuel is drawn from the tank through the primary filter by a gear-type transfer pump. The fuel then flows through the secondary fuel filter. The fuel is then directed through the Electronic Control Module (ECM) housing fuel gallery for cooling purposes.
Next, the fuel enters the low pressure supply gallery located in the cylinder head. Any excess fuel not injected leaves the cylinder head. The flow then passes through the pressure regulating valve, which limits pressure to 415 kPa (60 psi). Minimum pressure is 310 kPa (45 psi).
From the pressure regulating valve, the excess flow returns to the tank.
The ratio of fuel between combustion and fuel returned to the tank is approximately 1:3 (i.e. four times the volume required for combustion is supplied to the system for combustion and injector cooling purposes). A fuel temperature sensor is installed in the filter base (shown above) to compensate for power losses caused by varying fuel temperatures.
¥¥ PrimPrimary fuary fuel filel filter anter andd water separator water separator (arrow) (arrow)
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Fuel is drawn from the tank through the Primary Filter (arrow). The Primary Fuel Filter contains a water separator which is a vital part of the fuel system.
Any high pressure fuel system will deteriorate rapidly if water is allowed to circulate through the system. Water can cause early wear out or seizure of the injectors due to a lack of lubricity and corrosion.
The normal expected fuel system life will notnot be achieved if contaminated fuel is used. Use clean fuel and keep it clean.
The Primary Filter has a rating of 30 microns.
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¥¥ Water Water contcontaminaminatioationn reduces injector life reduces injector life
1.
1. TranTransfer pusfer pumpmp
2.
2. SeconSecondary fildary filter ter
¥¥ BypBypass ass valvalveve
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The fuel flows from the Primary Filter, to the Transfer Pump (1) to the Secondary Filter (2) partly hidden from view.
The fuel transfer pump contains a bypass valve to protect the fuel system components from excessive pressure. The bypass valve setting is higher than the setting of the fuel pressure regulator (next view).
The fuel transfer pump is driven by the front gear train.
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1 1 2
2
¥¥ SecoSecondarndary fuel y fuel filtfilter er
¥¥ FuFuel prel pressessureure regulator regulator
¥¥ RemRemotote moune mountedted secondary filter secondary filter
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Fuel flows from the Transfer Pump to the Secondary Fuel Filter shown here. Return fuel from the injectors flows through the Fuel Pressure Regulator in the Fuel Filter Base before returning to the fuel tank.
Fuel system pressure is controlled by the Fuel Pressure Regulator mounted in the Fuel Filter Base. This valve is set at 415 to 450 kPa (60 to 65 psi).
The Fuel Pressure Regulator is positioned downstream of the injectors.
Fuel which passes through the valve is returned to the fuel tank.
Fuel pressure can be checked at the Fuel Pressure Regulator Valve by removing a plug and connecting a gauge.
The Secondary Filter has a rating of 2 microns. It is vital to the life of the injectors that the correct filter with the correct micron rating is used.
NOTE:
NOTE: The Fuel Filter Base The Fuel Filter Base is remotely mounted is remotely mounted (off the engine) on(off the engine) on the D350E and D400E machines for improved accessibility.
the D350E and D400E machines for improved accessibility.
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¥¥ ECECM (M (arrarrowow))
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Fuel flows from the Secondary Filter to the ECM (arrow) and then to the front of the cylinder head and to the fuel injectors.
As in most applications, the ECM Fuel is cooled by fuel. This feature prevents excessive heat coming from the injectors drivers from causing
damage.
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¥¥ CyliCylinder nder head head fuelfuel supply passage supply passage
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This view shows injectors, injector sleeves and the fuel supply passage.
A larger volume of fuel passes through the injector than is required for injection and combustion. This extra flow is used to cool the injector which is normally surrounded by hot coolant.
From the rear of the cylinder head, fuel flows to the return side of the secondary filter base, which contains the Fuel Pressure Regulator.
From the Fuel Pressure Regulator, fuel returns to the tank.
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¥¥ ChChaptapter reer revievieww
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INSTRUCTOR NOTE:
INSTRUCTOR NOTE: TTo reinforce o reinforce this presentation, the followingthis presentation, the following tasks may be demonstrated on an engine using the Service Manual tasks may be demonstrated on an engine using the Service Manual procedures:
procedures:
Review the component functions using this slide.
Review the component functions using this slide.
Remove and install a unit injector.
Remove and install a unit injector.
Perform the necessary injector height adjustments.
Perform the necessary injector height adjustments.
Calibrate the injectors.
Calibrate the injectors.
Prime the fuel system.
Prime the fuel system.
Using ET, perform Injector Solenoid and Cylinder Cutout Tests.
Using ET, perform Injector Solenoid and Cylinder Cutout Tests.
Check for active and logged faults.
Check for active and logged faults.
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FUEL GALLERY FUEL GALLERY
EUI EUI EJECTORS EJECTORS
FILTER BASE FILTER BASE
TEMPERATURE CHECK VALVES CHECK VALVES PRIMING PRIMING PUMP PUMP
¥¥ FouFour syr system stem powpower er supplies
supplies
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