CATERPILLAR Common Rail Fuel System
CATERPILLARCommon Rail Fuel System
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CATERPILLAR Common Rail Fuel System
CATERPILLAR Common Rail Fuel System
CATERPILLAR Common Rail Fuel System
Orifice
CATERPILLAR Common Rail Fuel System
Electronic Control Module (ECM)• ECM Controls:
– Fuel Pressure– Speed Governing– Air/Fuel Ratio– Start/Stop Sequence– Engine Protection
Devices/ Diagnostics
CATERPILLAR Common Rail Fuel System
Fuel Pump Function• Pump Raises Pressure• ECM tells Injector to Fire• Rail Pressure Drops• ECM Detects Pressure Drop
–Sensed by Fuel Rail Pressure Sensor
• ECM tells Pump Solenoid to Increase Volume–Also tells Pump Solenoid to
Spill fuel once pressure is reached
• Do it Again!
CATERPILLAR Common Rail Fuel System
Fuel in from
Secondary Filter
To Fuel HP
Manifold
Pump Speed
Position Sensor
From
Primary
Filter
Fuel Leak off to Tank
To
Secondary
Filter
Oil lubrication
Locks the Pump
CATERPILLAR Common Rail Fuel System
Transfer Pump
Driven by High Pressure PumpDraws Fuel through Primary FilterOutput Pressure
300 to 600 kPa
Transfer Pump Primed by Priming Pump
Hand or Electric
CATERPILLAR Common Rail Fuel System
Fuel Manifold Injector Lines
High Pressure Fuel SystemDo’s & Don’ts
Do Check for leaks Do Not Loosen HP Connection with Engine RunningDo Replace HP Pipes After they are LoosenedDo Replace ALL Hp Pipes if new manifold is InstalledDo Not Force Pipes to FitDo Cap Manifold and Injector Connections Immediately when HP Pipe is removed
High PRV
Rail Pressure Sensor
CATERPILLAR Common Rail Fuel System
High Pressure
Relief Valve
Fuel Pressure Relief Valve
Protects System from Over-Pressure
Opens at Constant Pressure of 160 MPa (23,000 PSI)
Withstands Spikes to 190 Mpa (27,500 PSI)
Returns fuel to Tank
CATERPILLAR Common Rail Fuel System
Fuel
Return
from
Head
LIne
Fuel Return from Head
Excess Fuel Returned to Transfer PumpNot High Pressure
CATERPILLAR Common Rail Fuel System
Injector Function
Injector De-energizes
Valve Closes
Unused fuel flows back to Transfer Pump via passage in the Head
CATERPILLAR Common Rail Fuel System
Fuel Injector
Do’s and Don’tsDo Write down the Injector Serial Number and Confirmation Code before you install the Injector
Do use Cat ET to Program ECM with proper Injector Trim File
Do Look for the Trim File CD in the Injector Box
CATERPILLAR Common Rail Fuel System
Injector Adaptive TRIM
Fuel System Optimization RoutineRuns every hundred hours or so
Audible changes when engine is running
NO performance or Power Changes
Everything’s OK
Similar to HD ACERT engines
CATERPILLAR Common Rail Fuel System
CATERPILLAR Common Rail Fuel System
Cat Common Rail Fuel SystemC175
Meets emissions
Lower fuel consumption
Better transient response
Advantages
High Pressure Rail
High Pressure Pump
Secondary Fuel Filters
Fuel Tank
CoolerPrimary Fuel Filter/
Water Separator
Electric Priming Pump
CATERPILLAR Common Rail Fuel System
Cat Common Rail Fuel System
Low Pressure Fuel System
FTP
Electric Priming
Filtration
CATERPILLAR Common Rail Fuel System
Cat Common Rail Fuel System
Fuel System
HP Pump
Double Wall Lines
Double Wall Rails
Flow Limiter
Injector
CATERPILLAR Common Rail Fuel System
Cat Common Rail Fuel System - HP Rail
HP Rail
Double WallCrossover Line
Double WallLines From HP Pump
To Rail
Low PressureInjector return Pressure Sensor
CATERPILLAR Common Rail Fuel System
High Pressure Fuel System Hardware
Oil Return Flow Control Valve
PRV Outlet
Oil Supply
Camshaft
FTV Drive
HP Outlet
PRV
CATERPILLAR Common Rail Fuel System
Flow Limiter
• Flow Limiter Protection Device
Against Cylinder Over Fueling
Piston Moves With Every Injection
Trips at Set Point To Prevent Continuous Injection and Remains Shut
Spring
Piston
CATERPILLAR Common Rail Fuel System
CATERPILLAR Common Rail Fuel System