Transcript
Presentation Objective
At the end of this presentation you will be able to:• Describe the benefits of electronically controlled
engines.• Answer basic questions relating to system
components.• Use a multi-meter to perform continuity, Ohms and DC
volts• Understand the functions of Electronic Technician (ET)• Describe the basic concept of Controller Area Network
(CAN) and SAE J1939.
Caterpillar 3000 Series 3054E/3056E
Electronic Control Module (ECM)
Manifold Pressure Sensor
Intake AirTemperature
Sensor
Engine Oil PressureSensor
Engine CoolantTemperature Sensor
Machine Interface Connector
Service Tool Connector
(Industrial Engine)
PrimarySpeed/Timing
Sensor
Bosch VP30Pump
3000 Series Basic Engine Schematic
Service ToolConnector
Intake ManifoldTemperature Sensor
Intake Manifold Pressure
Sensor
Primary Speed/Timing
Sensor
VP30 Electronic Distributor
Pump
36-1 Tooth Crank Gear
A4 E1
ET
PumpECU VLPM
Machine Interface Connector
Engine CoolantTemperature Sensor
Engine Oil Pressure
Sensor
System Components - Wiring Harness• Engine harness connects engine mounted sensors and
actuators to ECM• Traditionally wiring and connectors is highest cause of
reliability problems • Incorporates robust sealed connectors
• Connectors are designed for long service life
• Cable insulation is capable of withstanding temperature and fluid exposure
• Outer covering provides protection from damage due to vibration, heat and general abuse
• Harness routing and connector ‘keying’ is used to prevent incorrect connection of components
Electronically Controlled Fuel Systems
Caterpillar 3000 Series
VP30 Pump
Bosch VP30 Fuel Injection PumpPUMP CONNECTOR
Pump Supply/CAN Link/Engine Speed/Timing/
Fuel Shutoff Connector
Fuel Quantity Solenoid Valve
Pump ECU
Timing Control Solenoid
Secondary Speed/Timing
Sensor
Fuel Temperature Sensor
TRANSFERPUMP
PRESSUREREGULATOR
TIMING ADVANCEMECHANISM
TIMINGSOLENOID
FUEL QUANTITYSOLENOIDVALVE
DELIVERYVALVE
INJECTOR
SPEED TIMINGSENSOR
ELECTRONICALLY CONTROLLED FUEL SYSTEMHIGH PRESSURE STAGE
LIFTPUMP
(PRIMING PUMP)
DISTRIBUTORPLUNGER
ENGINE ECM(A4 CONTROLLER)
PUMP ECU
FUEL RETURNCHECK VALVE
CAMPLATE
ROLLER
RING
ROLLERPLATE
ORIFICE
A4 ECM (3054E/3056E)
One ECM fits all applications
Basic System - Interactions
CATDATALINK
Switches/Pushbuttons
Sensors:Pressure,Temperature,
Speed/Timing
INPUTS
Power Supply12 v or 24 v
5/8 voltssensor supplies and operationComputerHardware
+Software
ECM
CONTROLINPUTS OUTPUTS
Indicator lights
ActuatorsCables/Connectors
Cables/Connectors
Relays
OUTPUTSC.A.N.DATALINK
SERVICE TOOL PUMP TO ECM/FLASH
System Components -ECM Hardware
Analoguevoltage
PWM
PROCESSOR
MEMORY
OUTPUTS
Digital
PWM
COMMUNICATIONSLINKS
INPUTS
Digital
System Components - ECM HardwareECM hardware technology trends
• Size reducing through circuit integration and packaging technology
• I/O (inputs and outputs) increasing - expected to plateau
• Memory capacity increasing - more software, more data logging capacity
• Processing power increasing - more calculations within fixed loop time (typically 25ms)
• Environment becoming harsher - cab to engine bay to on-engine
• Reliability improving through packaging technology and manufacturing process improvements.
• Cost reducing - reduced component costs, optimised design, high volume manufacture
Electronic Control Module: Essential Facts
• High reliability
• External connectors most vulnerable
• No serviceable parts
• Never replace without full diagnostic test
• All warranty returns checked
• No fault warranty returns - no warranty credit
• ECM is the LAST component you should suspect being faulty
Sensor Types
Engine Speed Controls
System Components – Speed ControlsThrottle PositionSensors/Controls
• Cat Machines- Pulse Width Modulation (PWM)- Set Speed Switches
• Industrial Engine, pedal position/operator demand
- Pulse Width Modulation (PWM)
- Contacting, resistive track potentiometer type devices.
• Provide linear voltage output (0.5v to 4.5v)
• Should have idle validation switches on mobile applications for failure detection.
Volta
ge o
/p
Low Idle
High Idle
PWM Throttle Position Sensor• Ground
• +8 Volt supply
• PWM Output
Three wires:
System Components -Throttle Position Sensors
• Pulse Width Modulation (PWM) is an output that is defined by its duty cycle.
• The duty cycle is the relation between the time on to the time off.
• More consistent than a linear sensor type.
• Above 90% and below 10% implies there is an error present.
IDLE(0.9volts)
FULL THROTTLE (4.6volts)
System Components
• Passive Sensors:- Commonly known as magnetic pick-ups- Produce a sinusoidal voltage signal. Signal
conditioning is required in the ECM
• Active Sensor:- Hall effect- Produce a ‘conditioned’ square wave signal- More expensive than passive sensors
Engine Mounted Sensors
On Engine Sensor Wiring
ECM
14 INTAKE MANIFOLD PRESSURE
A
B
C
1
2
1
2
INTAKE MANIFOLD AIR TEMPERATURE
SENSOR COMMON
26 SENSOR VREF +5 VOLTS
34 SENSOR COMMON O VOLTS
15 ENGINE COOLANT TEMPERATURE
32 INTAKE MANIFOLD AIR TEMP
24 ENGINE OIL PRESSURE
49 CRANKSHAFT POSITION -41 CRANKSHAFT POSITION +2
1
CRANKSHAFT POSITION +
CRANKSHAFT POSITION -
ENGINE OIL PRESSURESENSOR
INTAKE MANIFOLDPRESSURE SENSOR
ENGINE COOLANTTEMPERATURE SENSOR
INTAKE MANIFOLDTEMPERATURE SENSOR
SPEED AND TIMING SENSORNO.1
J103 P103
J401 P401
L730
994X731
995
C967L731
E965
P1 J1
33 CRANKSHAFT POSITION SCREEN
ENGINE COOLANT TEMPERATURE
SENSOR COMMON
J100 P100
A
B
C
SENSOR VREF +5V
ENGINE OIL PRESSURE
SENSOR COMMON
J201 P201
SENSOR VREF +5V
INTAKE MANIFOLD PRESSURE
SENSOR COMMON
J200 P200
E966
System ComponentsTemperature Sensors
• Thermistors:
- Semiconductor sensing devices
- Resistance varies with temperature
- Negative Temperature Coefficient (NTC) most common i.e. As temperature increases its resistance decreases
- 40 to 300ºF range
- Passive sensor ⇒ lower cost
Temperature Sensors
• Thermistor
Pin No 2
Pin No 1
Ground
Signal
Temperature Sensors
• 3054E/3056E Applications
- Intake Manifold Temperature Sensor
- Engine Coolant Temperature Sensor
System Components -Temperature Sensors
VoltsOhms(Resistance)
VoltsOhms
5.025,000
5,0000.5
Increasing Temperature
+5 VOLTS REFERENCESUPPLY
ANALOGUE TODIGITAL
CONVERTER
MICROPROCESSOR
R2
0 VOLTS
ECM
Temperature (Passive)Sensor Operation
R1
TEMPERATURESENSOR
System Components -Pressure Sensors
Pressure:
• Active Sensors (i.e. with built in conditioning electronics) provide analogue voltage output with linear and temperature compensation.
• Various working ranges to suit measured parameter e.g.
- 12 to +17 psi (abs) - Atmospheric pressure
0 to 70 psi (abs) - Intake manifold pressure
0 to 115 psi (abs) - Engine oil pressure
abs = absolute (pressure)
Pressure Sensors
Oil Pressure Sensor
Intake ManifoldPressure Sensor
A (5 Volts)
B (Sensor Return)
C (Signal)
Pressure Sensors
Change of Voltage with Pressure.
Out of range4.5
Volts
0.5Out of Range
Pressure
+5 VOLTS REFERENCESUPPLY
ANALOGUE TODIGITAL
CONVERTERMICROPROCESSOR
0 VOLTS
+12V
ECM
Pressure Sensor Circuits
System Components
Other Sensors (Industrial):
• Coolant Level Sensor
System Components
Speed/Timing Sensors• Applications:
- Determine rotational speed and rotational position
• Primary - Crankshaft speed and position
• Secondary - Camshaft/fuel pump speed and position
Primary Speed/Timing Sensor
Speed/Timing Sensor
70 Degrees4 CYL
40 Degrees - 6 Cylinder
Top Dead Center
Rotation
• The 3000 series engines use a 36-1 tooth ring. i.e. the timing ring has space for 36 teeth, and one is missing. The missing tooth allows the ECM to determine the timing of the engine. The wheel is dowelled to index it to the crankshaft.
System Components - Speed Sensors
Iron Core
Teeth
Pole Piece
Passive Speed Sensors Magnet
Coil
Flux Lines
Direction ofmotion
Secondary Speed/Timing Sensor Installation
Cra
nksh
aft
Speed/Timing Sensor
ECM
(6 cylinder Engine)
System Components – Speed/Timing Sensors
Speed/Timing Sensors – failure ModesPrimary sensor
Defaults to SecondarySecondary sensor
Engine stops and will not start
Teeth
System Components -Output Devices
• Typically include:
- Relays
- Lamps
- Gauges (PWM)
System Components - Actuators
Electronically Controlled Fuel Pump
• “Intelligent” rotary pump e.g. Bosch VP30
- Local pump mounted ECU controls pump solenoids to achieve desired fuel delivery and timing.
- Main ECM communicates desired timing and fuelling via CAN communication link
Electronic Service Tools
• Communication Adapter (CA II)
• CAT ET (Electronic Technician)
Electronic Service Tools
CAT ET Service Tool:
• PC based, multi function
- Status Screens
- Diagnostics
- Flash Programming
Electronic TechnicianCAT ET
The first element of STW (Service Technician Workbench)
Common for all future Caterpillar electronic engines
Hardware and software required
Annual subscription
Not compatible with Perkins 1100 Series engines
Communication Adapter GroupET Service Tool
CAT ET (Electronic Technician)Functionality includes:
Fault CodesData recording and graphingEngine Configuration Horsepower, customer operational parameters, P.T.O. cruise, Multi-position switch.
Flash Programming (ECM re-programming)Supports troubleshooting processDisplays parameters, temperature, speed, pressure etc.
Electronically Controlled EnginesARE ABLE TO
• Indicate active faults, logged faults and events
• Identify sensor and actuator short and open circuits
CANNOT
• Troubleshoot themselves
• Identify inaccurate sensor readings
Application Wiring
Warning Lamps
J20P20
IN LINE FUSE (F3)
J1P1MIC CONNECTOR ECM CONNECTOR
Stop Lamp
Warning Lamp
2312
2312
Data Links
Cat Data Link (CDL)
Controller Area Network (CAN)
(Two CAN data links on 3054/56E)
Example of CAN wiring
MACHINE INTERFACE CONNECTOR
Ohm TERMINATINGRESISTOR
120 Ohm TERMINATINGRESISTOR
5261
GEARBOXECM
Address 3
INSTRUMENT PANEL
Address 23
ENGINEECM
Address 0
HAND HELDSERVICE TOOL
Address 249 DATA BUS
NODE
NODE
The CAN shield not connected to ECM
Controller Area Networks (CAN)
Introduction:
• CAN is the communication network between intelligent electronic devices used on an application.
• Ground based equipment use a version of CAN that conforms to an international standard known as J1939
• Application control, monitoring and diagnostics is possible using J1939.
Controller Area Networks (CAN)
Advantages:
• Uses less wiring, lower weight, lower cost, etc.
• Uses fewer connections, more reliable.
• Easier to install.
• Improved quality of signal.
• Transmission of huge amounts of data.
3054E/3056E CAN Data Link Usage
CAN J1939
• Flash Programming
CAN Proprietary Data Link
• ECM to Pump ECU communication
CAN - J1939Examples of CAN Data link Uses:
• ECM to Engine Fuel Pump: Transmits engine power requirements to pump ECU
• Transmission to Engine: Tells the engine what gear is currently selected
• Engine to Machine: Broadcasting of engine parameters (e.g. engine speed, oil pressure, coolant temp.)
Flash Programming
Bus Fault Finding - (CAN)
Ensure CAN high and low wired connected correctly
Check shield
Ensure 120Ω resistors wired correctly
Ensure that no short circuits are present
Check for possible electrical interference
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