SUTRAC DEVELOPMENT & LEARNING CENTRE

Service Training
3500B

2. EUI FUEL SYSTEM

Block diagram
ECM & PM
ECM functions
Injector
Timing
RTC
REV: 8 May, 2001
Chapter: 2 3500B
EUI FUEL SYSTEM

FUEL SYSTEMS

TODAYS FUEL SYSTEMS AT CATERPILLAR:

Pump & lines - Multiple plunger pump

- High pressure fuel lines
- Injection nozzles

- Limited injection pressure (18.000 PSI)*

- Limited injection timing
- Limited injection rate capabilities

MUI - Mainly used on large engines to eliminate the need

for long high pressure lines and the related problems
inherent with controlling pressure in these lines.
- Requires an additional cam lobe, lifter, push rod
and rocker arm for each cylinder.

*Current engine emissions and performance requirements demand injection

pressure in excess of 20.000 PSI and greater timing flexibility.

PEEC (Programmable Electronic Engine Control)

- ECM takes over of the functions of the mechanical
governor.
- Fuel pump is still used.
- Throttle linkage replaced by electronic throttle.
- Air fuel ratio control electronically controlled.
- Engine is equipped with various sensors for monitoring.

EUI / MEUI (Mechanical Electronic Unit Injectors )

- Fuel is metered electronically by means of a solenoid
operated poppet valve.
- System still requires a mechanical valve train to
actuate the plunger.
(Mechanically actuated , electronically controlled)
- Fuel transfer pump replaces the "pump & lines".

HEUI (Hydraulic Electronic Unit Injectors )

- Plunger movement is not limited to speed or duration

of a cam lobe.
- Plunger speed is a function of actuation pressure
versus fuel pumping resistance.
(Hydraulically actuated , electronically controlled)
- Injection pressure is +20.000 PSI

Page: 2
Chapter: 2
3500B
EUI FUEL SYSTEM

BLOCK DIAGRAM

ECM

Electronic
Instrument
Injector Woodward Panel
Load Sharing
Speed/ timing Sensor Module
Timing Cal
Ether Solenoid Connector
Pre-Lube
Pressure Switch
Start / Stop Switch
Coolant Temp Sensor Speed Trim
Pre-lube Press Potentiometer
Switch

A/C Temp Sensor Coolant Level Sensor

Air Shut Off S
E-Stop switch

Fuel Level Switch

RH Turbo Inlet Elect Starter
Exhaust Temp Sensor Inlet Air Temp
sensor Charger Fault Switch

Air Starter Engine oil Temp 7 dry contact

LH Turbo Inlet Sender PRCM
Exhaust Temp Sensor
Crankcase
Press sensor CCM

RS232 RDM1
Atmospheric Filtered oil
Pressure Sensor Press sensor
RDM2 9 dry contact
Turbo Outlet Unfiltered oil OR
Pressure Sensor Press sensor

Filtered Fuel OR
LH Turbo Inlet
Pressure Sensor Press sensor

OR
RH Turbo Inlet Filtered Fuel
Pressure Sensor Press sensor

PC

Page: 3
Chapter: 2 3500B
CHAPTER :EUI FUEL SYSTEM

SENSOR FUNCTION

SENSOR FUNCTION

Throttle Position DESIRED RPM

Speed/Timming ACTUAL RPM

and
CYLINDER POSITION

This sensor is the reference

point for the gauge pressure
Atmospheric Press of all the other pressure sen-
sors

This pressure is needed to

Boost Press calculate the exact quantity
of fuel ( FRC )
( no air no fuel )

Oil Pressure Determine oil pressure for

oil map

Coolant temp Determine coolant temp and

cold mode

Fuel temp Determine fuel temp to make

correction to the fuel rate

Page: 4
Chapter: 2
3500B
EUI FUEL SYSTEM

ECM & PM

E C M

Personality Module
Software where the instructions are for
the ecm to do its job .
Perforrmance Maps

Electronic Control Module

Microprocessor for computing Permanent Memory
get its instructions from the - Programmable
personality module configuration
parameters
- Logged Diagnostics

Input Power Output

Circuit Circuit Circuit

- Signals From Sensor

- Filter Electrical Noise - From Battery
( 8vdc Minimum ) - To Sensors - To Rack And Lamps
- Protect Voltage Levels

Page: 5
Chapter: 2 3500B
EUI FUEL SYSTEM

ECM PRIMARY FUNCTION

MOST IMPORTANT FUNCTION OF THE ECM

IS TO GOVERN THE ENGINE

OK
GET READY

OK!!!!!
LET'S CALCULATE THE TIMING BASED ON
SPEED/TIMING WHEEL
-AFTER COOLER TEMP
-ENGINE SPEED
-TORQUE
-TIMING CALIBRATION
-E-TRIM CODES
KNOW THE AMOUNT OF FUEL BASED ON
-ACTUAL ENGINE SPEED
-DESIRED ENGINE SPEED
WHAT ARE THE FUEL LIMITS ?
FRC engine speed, boost pressure

Page: 6
Chapter: 2
3500B
EUI FUEL SYSTEM

ECM SECONDARY FUNCTION

DIAGNOSTICS ?

MONITOR SENSORS

MONITOR SWITCH INPUTS

THERE IS A PROBLEM !
SHOULD I , WARN , DERATE or STOP ?

I CAN SPEAK TO :
EMCPII
ENGINE VIVION
PRCM
CCM
SERVICE TOOL

Page: 7
Chapter: 2
3500B
EUI FUEL SYSTEM

INJECTOR ACTUATION

ELECTRONICAL CONTROLED MECHANICALY ACTUATED

FILTER

RELIEF
VALVE

E C M

Electronic
Unit
Injector
PUMP

FUEL
TANK
Page: 8
Chapter: 2
3500B
EUI FUEL SYSTEM

INJECTOR INJECTION

5
4

10
11
1. Solenoid Connection
2. Solenoid Valve Assem
3. Spring 12
4. Valve
5. Plunger
6. Barrel
7. Seal
8. Seal 1

9. Spring
10. Spacer
11. Body 2
12. Check
3

5
4

10
11

12

Page: 9
Chapter: 2 3500B
EUI FUEL SYSTEM

TIMING

TIMING GEAR TOOTH TABLE

TABLE DUTY CYLINDER
ENTRY CYCLE REFERENCE
1 80 %
2 50 % CYLINDER #1 TDC
3 80 %
4 80 %
5 80 %
6 50 %
7 50 %
8 80 %
CCW

CYLINDER #1 REFERENCE CYLINDER #1 TDC

1 2 3 4 5 6 7 8

Page: 10
Chapter: 2
3500B
EUI FUEL SYSTEM

EXAMPLE OF ACTION

Start Of Logic (SOL) Start Of Injection (SOI)

TDC REFERENCE

SPEED/TIMING
WHEEL

SIGNAL TO SPILL
VALVE SOLENOID

SPILL VALVE
TRAVEL

INJECTION
PRESSURE
CURVE

Time Delay

Page: 11
 3500 B ELECTRONIC GOVERNOR
Chapter: 2

jacketwater aftercooler
SHUTDOWNS DERATES
temp temp

3500 B
SPEED CONTROL LOGIC

8
7 ELECTRONIC
SIGNAL 6 GOVERNOR
FUEL DESIRED SPEED
TO FUEL 5 INJECTION
INJECTORS 4 CONTROL
3
2 FRC TORQUE
1 MAPS MAPS ENGINE THROTTLE
CONTROL
TDC #1 LOGIC

TURBO OUTLET,
TURBO INLET &
ATMOSPHERIC
PRESSURE SENSORS
SPEED/TIMING
SIGNAL
EUI FUEL SYSTEM
3500B

ACTUAL SPEED

TIMING FRC
FRC
WHEEL Offset
Offset

SPEED/TIMING
ELECTRONIC FUEL SYSTEM

SENSORS

Page:
12