40 RT-Flex WECS-9520 Control

RT-flex TraininggFunction of the RT-flex

C t l S tControl SystemWECS-9520

Chapter 40

© Wärtsilä Land & Sea Academy Page 1 Chapter 40 Feb. 2010

Rev. 025.06.08

RT-flex, WECS-9520 Control Systems Overview

The RT-flex engine control consists ofg

internal engine control WECS-9520 and the

external Propulsion Control System (PCS) (not Wärtsilä supply) withRemote Control (ECR Bridge)Remote Control (ECR, Bridge)Safety SystemElectric GovernorAlarm Monitoring System


RT-flex, WECS-9520 Control Systems Overview

OPIBridge

ECRECRAMS SS

fVE. G.

Engine roomEngine room


RT-flex, WECS-9520 RT-flex Concept

Basic RT-flex concept

Basic Schematic of the Wärtsilä RT-flex system with electronically controlled common-rail for fuel injection and exhaust valve operation.


RT-flex, WECS-9520 WECS-9520

CSEngine control system WECS-9520:

The WECS-9520 is the core engine control, it processes all actuation,g , p ,regulation and control directly linked to the engine:

Common rail monitoring and pressure regulationCommon rail monitoring and pressure regulationInjection and exhaust- and start valve control and monitoringInterfacing external systems via CANopen or MOD Busg y pEngine performance tuning, IMO setting and -monitoring

WECS-9520 has no central computer but each cylinder has its own FCM-20 module for the cylinder related- and common functions.


RT-flex, WECS-9520 WECS-9520

These FCM-20 modules are mounted directly on the engine andy gcommunicate via internal System CAN Bus. An operator access to theWECS-9520 is integrated in the user interface for the propulsion controlsystem and flexViewsystem and flexView.

WECS-9520 is neither an engine remote control system nor a safetysystem.


RT-flex, WECS-9520 Remote Control

Remote control system:K b M iti NABTESCO LKongsberg Maritime, NABTESCO, Lyngsø

The remote control is the operator interface to the engine. Selectable control panels deliver following manoeuvring commands to the WECS-9520 via CANbus or MODbus connection:

Start Brake air • Air runStart, Brake air • Air run

Stop • Slow turning

Ahead • Slow turning failure resetAhead • Slow turning failure reset

Astern

The remote control processes the engine telegraph command with internal settings (scaling, load program etc.) to a speed reference signal for the governing system


governing system.

RT-flex, WECS-9520 Lyngsø


RT-flex, WECS-9520 Kongsberg Maritime


RT-flex, WECS-9520 NABTESCO


RT-flex, WECS-9520 Electronic Governor

Electronic governor system:K b M iti NABTESCO LKongsberg Maritime, NABTESCO, Lyngsø

The electronic governor system supplies the fuel command for the WECS-g y9520 and regulates the engine speed

The fuel command is calculated from the speed reference signal of the RCThe fuel command is calculated from the speed reference signal of the RC-system in relation to the engine load. Fuel limiter in the governor system limit the fuel command depending on actual speed and charge air pressure

( &to avoid engine operation beyond the propeller law curve (smoke & torque limiter)

Critical speed range and other restrictions by the propulsion system are programmed to the governor system


RT-flex, WECS-9520 Safety System

Safety system:Kongsberg Maritime, Lyngsø

The safety system activates slowdowns and shutdowns in case of abnormal conditions of the engine or its auxiliary equipment. The function with the RT flex engine is similar to the conventional engines with somewith the RT-flex engine is similar to the conventional engines, with some different / additional functions:

WECS-9520 uses redundant BUS communication with safety system

The safety system (not WECS 9520 !) directly activates the hardwiredThe safety system (not WECS-9520 !) directly activates the hardwired emergency-stop solenoid to depressurize the fuel common rail


RT-flex, WECS-9520 Safety System

Additionally the safety system delivers some digital outputs to WECS-9520 via CAN Module Bus:

Inverted main bearing oil shutdown signals for starting and dry-running protection of the control oil pumps

Shutdown signal to WECS-9520, to activate WECS-internal shutdown responses

WECS-9520 failures requesting speed reduction are activated by the governor system through AMS to the safety system


RT-flex, WECS-9520 Alarm Monitoring

Alarm monitoring system:Any possible system with class approval

The monitoring system receives alarm messages, divided in two groups:Some general failures alarm signals are hardwired via E130 and E90 for follo ing general fail resfollowing general failures:

• Leakage Alarms: Rail Unit, Supply Unit, Injection Components

• Fuel Pressure Actuator FailureFuel Pressure Actuator Failure

• Fuel Pump Outlet Temp Deviation Monitoring

• Servo Oil Flow Monitoring (Dynex pumps only)

• WECS-9520 Power Supply Monitoring



Other WECS 9520 failure signals are transmitted via redundant (module ) busOther WECS-9520 failure signals are transmitted via redundant (module-) bus connection:

The standard WECS-9520 execution uses a Modbus interface to send failure messages to the AMS via WECS-9520 modules FCM-20 #3 and FCM-20 #4

If both propulsion control and alarm monitoring systems are from Kongsberg Maritime (Autochief C20 and Datachief C20), then the monitoring system can access WECS-9520 directly via CANopen interface to FCM-20 #1 and FCM-20 y#2 and no Modbus connection is required



WECS-9520 failures on the AMS:

Total 6 different groups of WECS-9520 failures are transmitted via CAN / Modbusto the alarm monitoring system:

Passive FailuresFailures of redundant sensors, busses or components, p

Common FailuresCylinder unit failures without redundancy or common system failures that do not cause any speed reductioncause any speed reduction

Cylinder FailuresAny cylinder unit failures that cause a slowdown via AMS / SS

Rail Pressure FailuresCommon rail pressure failures that cause a slowdown via AMS / SS

Cylinder Lubrication Malfunction (Pulse Lubrication only)Cylinder Lubrication Malfunction (Pulse Lubrication only)Any cylinder lubrication malfunction that causes a slow down via AMS / SS

WECS-9520 Critical FailuresSystem critical failures that cause immediate stopping of main engine (not by AMS /


System critical failures that cause immediate stopping of main engine (not by AMS / SS) and can not be overridden by safety system

RT-flex, WECS-9520 Bus Systems

Bus systems used for WECS-9520:Bus systems used for WECS 9520:CANopen System Bus

CANopen Module BusCANopen Module Bus

ModBus

SSI BSSI Bus


RT-flex, WECS-9520 Standard SystemControl Room 2 x 230VAC

ECR Manual Panel flexViewflexView

PowerSupplies

2 x 230VAC

WECS-9520

CANopen or ModBus#1 Module Bus #2

CANopen System Bus Mod

Bus

#3

Engine room

Rail Unit

Mod

Bus

#4

CANopen Module Bus #3 CANopenModule Bus #0

CANopen System Bus

FCM

-20

FCM

-20

FCM

-20

FCM

-20

FCM

-20

FCM

-20

FCM

-20

M M

Cyl

. 1

Cyl

. 2

Cyl

. 3

Cyl

. 5

Cyl

. 6

onlin

e sp

are

Cyl

. 4

E90 SIB

Crank-Angle SSI Bus

E90 SIBE95.1 E95.6n

/ PW

M

VCU3x ICU

Starting Valve

Local Manual CO Pump CO Pump

4-20

mA

CA

No

CA

N

CA 2

Servo oil Pump

Servo oil Pump

CA 1RT-flex EngineActuator for Fuel Pump

CA

Nop

e3x ICU Panel Actuator for Fuel Pump

Servo oil Pump

Actuator for Fuel Pump

Servo oil Pump


openM

odule Bu

Nopen

Module B


CANopen Module Bus #4Cyl. Lubrication Modules

ALM-20 ALM-20 ALM-20 ALM-20 ALM-20 ALM-20

us #n-1

Bus #n

RT-flex, WECS-9520 Standard System “Kongsberg”Control Room 2 x 230VAC

ECR Manual Panel flexViewflexViewOPI OPI

PowerSupplies

2 x 230VACOPI OPI

WECS-9520CANopen System Bus

Engine room

Rail Unit

CANopen Module Bus #3CANopen Module Bus #1 #2

CANopenModule Bus #0

CANopen System Bus

FCM

-20

FCM

-20

FCM

-20

FCM

-20

FCM

-20

FCM

-20

FCM

-20

Cyl

. 1

Cyl

. 2

Cyl

. 3

Cyl

. 5

Cyl

. 6

onlin

e sp

are

Cyl

. 4

E90 SIB

Crank-Angle SSI Bus

E90 SIBE95.1 E95.6n

/ PW

M

VCU3x ICU

Starting Valve

Local Manual CO Pump CO Pump

4-20

mA

CA

No

CA

N

CA 2

Servo oil Pump

Servo oil Pump

CA 1RT-flex EngineActuator for Fuel Pump

CA

Nop

e3x ICU Panel Actuator for Fuel Pump

Servo oil Pump


Servo oil Pump


openM

odule Bu

Nopen

Module B


CANopen Module Bus #4Cyl. Lubrication Modules

ALM-20 ALM-20 ALM-20 ALM-20 ALM-20 ALM-20

us #n-1

Bus #n

RT-flex, WECS-9520 WECS-9520 Functional Design

The WECS-9520 system is built with a single multifunctional electronic module FCM-20 = Flex Control Module 20.O FCM 20 i t d li d i bi t (E95)

Low signals, Low signals, BussesBusses and sensorsand sensors

One FCM-20 is mounted per cylinder in a cabinet (E95) below the rail unit.An additional online spare module FCM-20 is located in the SIB Shipyard Interface Box (E90)

High signalsPower PWMthe SIB Shipyard Interface Box (E90).

The modules communicate between each other on a fast internal CANopen system bus.Additionally each module has got two module busses (1x

Power, PWM, Railvalves

Additionally each module has got two module busses (1x CANopen, 1x MODbus) that are used for communication to external systems (PropCS, ALM), backup control panels, actuators (size IV).The internal module layout and the cable trays in the rail unit entirely separate circuits with high EMC noise, like power cables or pulsed current lines (PWM, rail valves) from sensitive low power lines like databus cables and E95.02

E90 SIB

from sensitive low power lines like databus cables and sensors.

Cable tray high

E95.01

Box Box


Cable tray low

RT-flex, WECS-9520 Bus cabling

Terminator resistorsTerminator resistorsAt each end of the Bus cable a terminator resistant of 120Ω MUST be installed to avoid signal reflectionbe installed to avoid signal reflection


RT-flex, WECS-9520 FCM-20 Module


RT-flex, WECS-9520High Power I/O

FCM-20 Hardware I/O HighHigh Power I/O

ICU, Rail valve #1

ICU, Rail valve #2

FCM-20 Hardware I/O

On the upper left-hand side of the FCM- ICU, Rail valve #2

ICU, Rail valve #3

pp20 are the interface plugs for the high/pulsed power outputs.LED’s indicate I/O condition. Some h h i l i f f il

VCU, Rail valve change their colour in case of failures or short circuits. Blink codes give detailed failure information.

Start Pilot Valve

24VDC out, Ctrl-Oil Pumps Auto. Main Start Valve

Supply Man. Ctrl. Panels

Servo Oil Pump Actuator

Power Supply 24VDC


RT-flex, WECS-9520Low Power I/O

FCM-20 Hardware I/O Low

FCM/20 Cylinder # Identification ErrorFuel Qty. Feedback ok / FailureExhaust V/v Position 1 FB ok / FailureExhaust V/v Position 2 FB ok / FailureA l I 1 (R il P Ch Ai ) / F il

FCM-20 Hardware I/O

On the lower right-hand side are the Analogue In 1 (Rail Pressure, Charge Air…) / FailureAnalogue In 2 (Rail Pressure, Charge Air…) / FailureAnalogue in 3 (Spare) / Failure

CA Sensor 1 Short Circuit Power Supply

ginterface plugs for low power signals and databusses.LED’s indicate FCM-20 module & I/O

di i S h h i l i CA Sensor 1 Short Circuit Power SupplyCA Sensor 2 Short Circuit Power Supply

CA-Sensor 1 Master / Clock or Data FailureCA-Sensor 2 Master / Clock or Data Failure

condition. Some change their colour in case of failures or short circuits. Blink codes give detailed failure information.

CAN System Bus 1 Master / Bus FailureCAN System Bus 2 Master / Bus FailureCAN Module Bus 1 Traffic / Bus Failure

MODbus Traffic

Digital Input 1 (Turning Gear Engaged; TDC Pick-up)Digital Input 2 (Pressure Switches)Digital Input 2 (Pressure Switches)Analogue Out (Fuel Actuator Set point)

Power Supply FailureModule ready, SW OKFailure on Module


Failure on ModuleNot Applicable

RT-flex, WECS-9520 FCM-20 Module Functions

Th i t l FCM 20 f ti ithi th WECS 9520 b t d iThe internal FCM-20 functions within the WECS-9520 can be separated in two groups:

Cylinder Related Functions

Common Functions


RT-flex, WECS-9520 Cylinder Related Function Interface

Cylinder related functions:For synchronizing the injection and exhaust valve control timing with the crankFor synchronizing the injection- and exhaust valve control timing with the crankangle, each FCM-20 reads and processes the crank angle signals from the SSI-Busand calculates speed, angle and rotational direction of its cylinder

Start-, injection- and exhaust valve control according to settings in data container andcommands and parameters received across CANopen System bus


RT-flex, WECS-9520 Cylinder Related Function Interface

Crankangle SSI Bus 2

Crankangle SSI Bus 1

CExhaust Valve

Position Feedback4-20 mA

24VDC outE85

Power Supply

24VDC

Fuel Quantity FeedbackFeedback4-20 mA

Injection Control Unit2 3 R il l

Exhaust Control Unit1 R il l

Start Pilot Valve

Crank Angle Sensorseach

1 Clockbus 1 Databus


2 or 3 Rail valves 1 Rail valve

RT-flex, WECS-9520 FCM-20 Module Functions

Common functions:Fuel and servo oil rail pressure monitoring and regulation control oil pumpsFuel- and servo oil rail pressure monitoring and regulation, control oil pumps control

Storage and processing of tuning data (IMO, engine-specific and global settings)

Internal WECS monitoring (power supply, SW-watchdog, CRC- & HW-checks)

Calculation and processing of common control variables (VIT, VEC, VEO, i t t t )engine state, etc.)

Interface to propulsion control system and to backup panels in ECR and LC

Failure indications with help of module LED'sFailure indications with help of module LED s

Aux. blower request at low charge air pressure


RT-flex, WECS-9520 Common Function InterfaceTurning Gear Disengaged (digital in)Turning Gear Disengaged (digital in)

Charge Air Pressure (4-20mA) 1 2

FCM

-20

l. 1

FCM

-20

l. 2

FCM

-20

l. 3

FCM

-20

l. 5

FCM

-20

l. 4

Cyl

Cyl

CylFuel Rail

Local MCP (CAN Module bus) ECR MCP

Cyl

Cyl

Servo Oil Rail

TDC Pi k (di it l i )

Servo Oil Pumps (PWM current 0-2,2A)

TDC Pickup (digital in)1 2 3

Fuel Supply Actuator (4-20mA)Automatic Start Valve (digital out)

1 2 31 2


RT-flex, WECS-9520 Common Function Interface “Control Oil”

T i G Di d (di it l i )Turning Gear Disengaged (digital in)


FCM

-20

. 1

FCM

-20

l. 2

FCM

-20

l. 3

FCM

-20

l. 5

FCM

-20

l. 4

Cyl Cyl

Cyl

Cyl

Cyl

Fuel RailLocal MCP (CAN Module bus) ECR MCP

Servo Oil Rail

Control Oil Rail

Some engine types only

Control Oil Pumps (digital out) TDC Pickup (digital in)1 2

Servo Oil Pumps (PWM)1 2 3

Automatic Start Valve (digital out)

1 2

1 2 3


Fuel Supply Actuator (4-20mA)1 2 3

RT-flex, WECS-9520 Common Function Interface “Bosch”Turning Gear Disengaged (digital in)Turning Gear Disengaged (digital in)


Size IV only

FCM

-20

l. 4

FCM

-20

l. 1

FCM

-20

l. 2

FCM

-20

l. 3

FCM

-20

l. 5

Cyl

Cyl

Cyl

Cyl

Cyl

Fuel RailLocal MCP (CAN Module bus) ECR MCP

Servo Oil Rail

Control Oil Rail

C t l OilControl Oil Flow (4-20mA)

TDC Pickup (digital in)1 2Control Oil Pumps (digital out)

Servo OilServo Oil Pumps (CAN Module bus)1 2 3

1 2 3Automatic Start1 2

Servo Oil Inlet Press.(4-20mA)


Fuel Supply Actuator (4-20mA)1 2 3Start Valve (digital out)

1 2

RT-flex, WECS-9520 Manual Control PanelsSimilar panels are installed in ECR andSimilar panels are installed in ECR and Local Control Panel. All necessary information is shown on the display:• Speed and / or Fuel Command• Start Interlocks

Select Speed or fuel control mode

• Safety events (SHD, SLD, OVSPD)• Rail pressures

Select Speed or fuel control mode

Speed or fuel commands are set with a dial button on the RC supplier part of the CR / LC panels.

Last command is stored when takingLast command is stored, when taking over to other panel or from remote to manual control.

Speed control mode is only possible, if the speed governor system in the PCS

Selector buttons for manoeuvring commands.

the speed governor system in the PCS and the bus connection is operational.

Start Air is released as long as AH / AS buttons are pressed. The engineer can decide, when and for how long start- or brake air is supplied.


Speed/fuel command

RT-flex, WECS-9520 Manual Control Panels

Resets shutdowns on the safety system START

AHEAD

A start sequence will be initiated to reach preselected engine speed /

Overrides shutdowns if pressed once, next pressing releases override (see to red LED indication)

STARTASTERN

power in requested direction if no starting interlock pending

Resets audible alarms from safety system and slow turning failures on this panel

STOP

Engine will be stopped immediately

panel If the Acknowledge button is pressed for more than 5 seconds, WECS-9520 SW info and all necessary IMO check values are indicated in the screen until

Releases starting air in ahead direction t bl i

Pre-selects blowers for automatic mode; start / stop depends on actual charge air pressure.starts blowers manually, if both charge air

button is pressed againto blow engine on air, as long as button is pressed

Releases a sensors fail. =>Display: Aux. Blower Man. Ctrl./ No Blowers running

Stops blowers during automatic mode only if engine is not running

slow turningsequence (one single turn).

Slow turning failures are i di d i h di l


engine is not running.In manual mode stops blowers at any time.

indicated in the display

RT-flex, WECS-9520 Rail Valves

Rail valves:

The rail valves are ultra-fast switching (~1 ms) electro-hydraulic solenoid valves. Due to the high actuation current and the thermal load gon the solenoid coils, they must not be energized for more than 4.5 ms. This “on”-time is sampled, monitoredand limited by WECS-9520

Rail valves are bi-stable, i.e. selected position remains until counter-direction is set by WECS-9520

After installing or replacing a bi-stable valve, its position (open or close) is unknown.To make sure the valves are always in the safe “No injection” and “Exhaust valve closed”

iti h th i i t dposition when the engine is stopped, WECS-9520 sends set-pulses to all rail valves in regular intervals (~10 s)


RT-flex, WECS-9520 Crank Angle Detection

Crank angle detection:

Without direct mechanical crank angle transmission to the control elements for fuel injection and exhaust valves, it is necessary to measure the actual crank angle electrically. The crank angle sensors for WECS-9520 have an absolute angle resolution, therefore the exact crank angle value is present immediately after powering up

Two such angle transmitters are connected with serrated belts to a specially designed drive shaft. This application preventsdrive shaft. This application prevents transmission of axial and radial crankshaft movements to the sensors

Each sensor transforms angle data from anEach sensor transforms angle data from an optical code disk into a bit frame. The FCM-20 modules read these bit frames from a SSI bus (Synchronous Serial Interface Bus)


(Synchronous Serial Interface Bus)

RT-flex, WECS-9520 Crank Angle Detection

To synchronize the messages between FCM-20 modules and CA-sensors, each SSI bus has its own clock bus the bit frames itself are sent via its data busSSI bus has its own clock bus, the bit frames itself are sent via its data bus

The two last FCM-20 are clock bus masters (e.g. #11 & #12 on a 12-cyl. RT-flex).I.e. FCM-20 #(last-1) supplies clock pulses to sensor 1 and the other modules on bus 1. FCM-20 #(last) supplies clock pulses to sensor 2 and the other modules on bus 2

Signals from both CA sensors are processed and checked for errors within eachSignals from both CA sensors are processed and checked for errors within each FCM-20

Sensor angle values are compared with TDC pulse signals from a pick-up on the fl h l If th TDC i l d t t h ith ’ k l tflywheel. If the TDC signal does not match with a sensor’s crank angle sector around 0°, a common failure or, depending on the deviation, a critical failure (engine stops) is initiated by the WECS-9520

The final master angle value is calculated from the measured angles and used to determine crank angle, engine speed and direction of engine rotation


RT-flex, WECS-9520 Injection Control

Injection control:(volumetric injection control)( j )

Each FCM-20 calculates the necessary injection timing for its own cylinder by processing the crank angle signal and the fuel command received from the speed control.

Normal operationSome degrees before the piston reaches TDC, the FCM-20 calculates the correct injection b i l t ki VIT d FQS i t id ti F th d dti i dd d tbegin angle, taking VIT and FQS into consideration. Further a deadtime is added to compensate the time-difference between the injection command from the control system and the real injection begin. The deadtime is measured during the injection cycle by comparing the elapsed time between command release and begin of movement fuelcomparing the elapsed time between command release and begin of movement fuel quantity sensor. The fuel quantity sensor further gives a feedback of the amount of injected fuel and is compared with the fuel command. Injection begin and end are triggered and actuated by the FCM-20


triggered and actuated by the FCM-20.

RT-flex, WECS-9520All components drawn in

Injection Control Unit

Schematic Layout of an Injection UnitWhen the rail valves are switched to “I j ti ” f l i li d f

All components drawn in position “Return” (No Injection)

“Injection”, fuel is supplied from volume through injection control valves 3.41 to the fuel nozzles. During fuel displacement the fuelDuring fuel displacement the fuel quantity piston moves inwards and delivers a feedback signal analogue to the injected fuel quantity to theto the injected fuel quantity to the FCM-20, which compares this value with the fuel command received from electronic governor

When the desired amount of fuel has been injected the FCM 20 switches the rail valves toelectronic governor. injected, the FCM-20 switches the rail valves to “return” position. A second time delay appears, before the quantity piston movement is terminated. This injection return delay is compensated inside

Injection Control ValvesFuel Quantity Signal

Servo (control) This injection return delay is compensated inside the WECS-9520. After the injection control valves interrupted the fuel supply to the injector nozzles, due to the rising pressure in space the fuelFuel oil side

Servo (control) oil side


due to the rising pressure in space the fuel quantity piston moves back to its initial position.

Rail Valves

Fuel oil side

RT-flex, WECS-9520 Injection CurveInjection sector with dead time correction

Injection dead times:

True Injection begin

Injection return overshoot

j gdead time

Injection begin dead time

Injection return dead time

Fuel command signal

Begin of injection threshold =4%

Injection↑

Injection quantity piston Return command

threshold =4%

In the upper graph the red curve shows a simplified injection curve, as given by the fuel quantity sensor during one injection stroke.

Injection command

j q y pbegin of movement

Return command

q y g jThe blue curve shows the command timeframe (angle) between the injection- and return commands to the rail valve coils. After an initial quantity piston movement of 4% the ramp is considered as injection. The time elapsed between the injection command and this point is the “true injection begin deadtime”.At the return command the piston movement still continues until the end of the return deadtime. This maximum injection value is used by WECS-9520 for actual fuel command


processing. The injection return overshoot is compensated by the external speed regulator (by adopting fuel command until desired engine speed is reached).

RT-flex, WECS-9520 Single Nozzle Control

Low load operation:At low engine load the WECS-9520 cuts out one or two of the three injection valves per cylinder.This is used to avoid visible smoke emission and to reduce fuel consumption. During any fuel injection the pressure of the injected fuel can only be controlled after an initial peak.To inject a certain fuel volume with one nozzle takes longer than with 2 nozzles. This longer injecting time allows a larger part of the fuel to be injected with a g p jcontrolled pressure and thus improved atomization for an optimized combustion.

To avoid thermal stress to cylinder liners the active nozzles are cycled every 20To avoid thermal stress to cylinder liners, the active nozzles are cycled every 20minutes. Cycling from one nozzle to another is done with a 20 seconds time delaybetween each cylinder to prevent smoke emission due to “cold” fuel injected throughthe new active hot nozzle


the new active hot nozzle.

RT-flex, WECS-9520 Single Nozzle Control

Sequential cut-out of injection nozzles for smokeless slow-steaming

Smokeless operation at low speedUsual operation

3 nozzlesin unison

Smokeless operation at low speed

Alt tiin unison Alternative2 nozzleoperation

Alt tiAlternative1 nozzleoperation

smokeless operation down to 12% rpm R1


smokeless operation down to 12% rpm R1

RT-flex, WECS-9520 Exhaust Valve Control

Exhaust valve control:

The exhaust valve is opened by servo oil pressure and closed by an air spring, same as with conventional engines. Instead of cam and roller the actuation is done by VCUs. The stroke of the valve spindle is measured by one or two analogue position sensorsThe stroke of the valve spindle is measured by one or two analogue position sensors for a feedback to the WECS-9520.

VCU Pi tVCU Piston

Slide rod


VCU rail valve


Detailed functional description of the exhaust valve control:

The valve opening angle is calculated in each FCM-20 according to measured crank angle, nominal opening angle and VEO (Variable Exhaust valve Opening)

The VCU rail valves are triggered to the “Open” position. Servo oil pressure operates the slide rod which supplies the servo oil to the space below the VCUpiston. The VCU piston compresses the oil in the actuator pipe, which finally opens the exhaust valve spindle

Rail valve Slide rod Piston Exhaust valve

Servo rail

Rail valve

Oil supply

Position sensor

Spring air



The time between the “Open” command and the initial movement of the spindle is measured. It is called opening deadtimep g

This deadtime will be considered by switching the rail valve a little earlier for compensation of hydraulic and mechanic delays

Analogue to the above mentioned, the valve closing angle is determined and controlled by the FCM-20 including the VEC (Variable Exhaust valve Closing) and a closing deadtime



t 15

% e

xhau

stva

lve

stro

ke

% e

xhau

st

ve s

troke

85%

valv

Exhaust valve open deadtime Exhaust valve close deadtime

The signal „Exhaust valve open” is triggered after 15% opening stroke already where for the “Exhaust valve closed” signal a closing stroke of 85% is needed. Therefore, the “Exhaust valve close deadtime” shown in the flexView is much longer than “Exhaust


valve open deadtime”.

RT-flex, WECS-9520 FQS, VIT

FQS, VIT:These functions are known from the conventional engines:

FQS: Fuel Quality SettingManual offset for the injection timing in relation to the fuel quality

VIT: Variable Injection TimingAdvance / retard injection according to engine load for optimized fuelAdvance / retard injection according to engine load for optimized fuel consumption and NOx emission.

Different from the RTA engines, the injection angles for the RT-flex are no more g , j grelated to the fuel cam angle (advanced injection begin => “+”, retarded => “-”), but to the

Crankangle (CA) between 0° - 360°.g ( )

As a result, an advanced injection begin or FQS setting [higher firing pressure] (e.g. +1.0° according to RTA philosophy) is now -1.0° in relation to the earlier injection


1.0 according to RTA philosophy) is now 1.0 in relation to the earlier injection angle (e.g. 2° instead of 3° CA).

RT-flex, WECS-9520 FQS, VIT

0.0

1.0

2.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2gle

[°C

A]

FQS, VIT: VIT A

-3.0

-2.0

-1.0

Charge Air Pressure [-]

IT A

Ang

The VIT angle calculation for the RT-flex depends on RPM, charge air pressure

g [ ]

and fuel rail pressure

This 3rd parameter is introduced to t diff i i j ti

VIT B

2 0

3.0

4.0

°CA

]

compensate differences in injection timing resulting from different fuel rail pressures

-2 0

-1.0

0.0

1.0

2.0

0 10 20 30 40 50 60 70 80 90 100 110 120IT B

Ang

le [

°

Higher fuel pressure causes advanced injection and higher Pmax

Thus the injection begin angle is

VIT C2.0

Engine Speed [%]

3.04.0

] Fuel Rail pressure at CMCRThus the injection begin angle is retarded a bit with increasing fuel pressure

3 0-2.0-1.00.01.02.0

0 200 400 600 800 1000 1200 1400 1600IT

C A

ngle

[°C

A]


-4.0-3.0

Fuel Rail Pressure [bar]

RT-flex, WECS-9520 VEO, VEC

VEO, VEC:

The VEC is known from the conventional RTA84T-B/D engines:

VEC: Variable Exhaust-valve Closing 5VEC

VEC: Variable Exhaust valve Closing

Adopting compression pressure to keep the firing ratio (P / P ) within permitted range 25

-20

-15

-10

-5

00 10 20 30 40 50 60 70 80 90 100 110 120

EC A

ngle

[°C

A]

ratio (Pmax / Pcompr) within permitted range during advanced injection.

VEO: Variable Exhaust-valve Opening

-35

-30

-25

Engine Speed [%]

VE

20 VEOVEO: Variable Exhaust valve Opening

Keeps the exhaust gas pressure blowback constant by earlier valve opening at higher 0

5

10

15

VEO

Ang

le [

°CA

]

constant by earlier valve opening at higher speed for fuel economy and less deposits at piston underside.

-50 10 20 30 40 50 60 70 80 90 100 110 120

Engine Speed [%]


VEC and VEO are calculated by WECS-9520 and can not be changed manually !

RT-flex, WECS-9520 Fuel Pressure Control


RT-flex, WECS-9520 Fuel pressure control

Example:

Rail pressure varies over engine load.

Low load: High pressure to optimize combustion (reduce smoke)Middle load and CMCR load: Low pressure to comply with IMO emission regulations


Service load: High pressure to optimize fuel consumption


StartingAl d t t d till th f l t t d t th i tiAlready at standstill, the fuel pump actuators respond to the existing pressure in the fuel rails and set their output accordingly

If at the beginning of the staring sequence the fuel pressure is still higher than g g g q p g400 bar, the actuators will be first at zero and than increase to setpoint

WECS-9520 monitors the fuel rail pressure and releases engine firing as soon as a minimum required fuel rail pressure is reachedas a minimum required fuel rail pressure is reached

This is one of the advantages of the RT-flex concept since, on the same engine revolution, some cylinders are still being pushed down by staring air, others

freceive already fuel

Starting air is finally cut-off at a certain speed limit set in the RCS system



Engine RunningTh t t itt th f l il d li th t lThe two pressure transmitters on the fuel rail deliver the current pressure value to WECS-9520. For faster response of the dynamic pressure regulation, any change of the fuel command for the speed control is additionally transmitted as feed forward to the control loopfeed forward to the control loop

WECS-9520 calculates the necessary rail pressure and the corresponding output signal to the actuators (4-20 mA signal)

The fuel pumps charge up the fuel rail pressure via intermediate fuel accumulator or direct to the fuel rail, depending on the engine type

f f fThe resulting pressure in the fuel rail depends on the quantity of fuel delivered by the supply unit and the amount of fuel injected


RT-flex, WECS-9520 Feed Forward

Pressure RegulationTh j k t f l t t t t tti l ith th tThe jerk-type fuel pumps react to a new actuator setting only with the next following delivery stroke. This generates a deadtime until the pumps can compensate against a raising or falling fuel rail pressure

To change the fuel rail pressure, a new fuel command is needed. For faster response of the dynamic pressure regulation any fuel command change is additionally transmitted as feed forward to the control loop

∑

Feed forwardr



ShutdownA shutdown from the Safety System is performed as follows:y y p

The safety system releases the pressurized intermediate fuel accumulator to the fuel return line by opening the hydraulic fuel shutdown valve 3 07 viathe fuel return line by opening the hydraulic fuel shutdown valve 3.07 via emergency stop solenoid 3.08 (ZV7061S)

WECS 9520 triggers the fuel actuator outputs to zeroWECS-9520 triggers the fuel actuator outputs to zerofor terminating fuel feed to the rail unit, while the engine is not yet stopped

Injection commands are blocked by the WECS-95203.08

The red lever is NOT meant for emergency stop 3.07


RT-flex, WECS-9520 Servo Oil Circuit


RT-flex, WECS-9520 Servo & Control Oil Circuit “Dynex”Some engine sizes onlySome engine sizes only


RT-flex, WECS-9520 Servo & Control Oil Circuit “Bosch”Some size 4 engine onlySome size 4 engine only


RT-flex, WECS-9520 Servo Oil Pressure Control

200

250

e [b

ar]The servo oil rail pressure is controlled

depending on the engine load. At part load the pressure is reduced to adjust the

0

50

100

150

vo O

il Pr

essuload the pressure is reduced to adjust the

opening speed of the exhaust valve against the lower remaining gas pressure in the cylinder 0

0 10 20 30 40 50 60 70 80 90 100 110 120

Engine Load (MEP x n) [%]

Servin the cylinder

WECS-9520 uses fuel command and speed as engine load reference to calculate the necessary setpoint for thecalculate the necessary setpoint for the servo oil pressure. Each servo oil pump is controlled by a different FCM-20

Dynex: A pulse-width modulated (PWM) current signal is supplied to the solenoid mounted on the control plate of the pumps. This signal is setting the output of the axial piston pumps to maintain the required servo oil rail pressure

Bosch: Pressure command and engine running direction are communicated via CANBosch: Pressure command and engine running direction are communicated via CAN bus to the Bosch electronic controller cards of the pumps

While engine at standstill, the control oil circuit feeds the servo oil rail with appro imatel 75 bar adj sted at press re red cing al e 4 27 (some engine t pes


approximately 75 bar, adjusted at pressure reducing valve 4.27 (some engine types only)

RT-flex, WECS-9520 Control Oil Pressure Control RT-flex84/96, MKI

The control oil pumps supply an oil pressure of 200 bar to operate injection control l d t i th il il ( ith d d ) h th i i tvalves and to prime the servo oil rail (with reduced pressure), when the engine is at

standstill. Control oil pressure is adjusted at pressure retaining valves on the control oil collector block

A dry-run protection in case of low bearing oil pressure is provided within the WECS-9520 software

Bosch Pumps:Below 50% engine load or control oil pressure less than 170 bar, both

ipumps are runningAt higher engine load one of the pumps is switched off

Dynex Pumps:Always one pump is running over the entire engine load range The second pump starts only if the control oil pressure delivered by the running pump drops below 170 bar


running pump drops below 170 bar

RT-flex, WECS-9520 Starting Valve Control

The automatic starting valve 2.03 is activated by solenoids ZV7013C and ZV7014C via FCM-20 #1 and FCM-20 #2, if the remote control sends a START signal

2.03

, gover the bus

The opening and closing of the starting pilot valves 2.07 is controlled by the corresponding FCM 20 dependingis controlled by the corresponding FCM-20, depending on the crank angle

The nominal opening angle is 0°, closing at 110°

On engines with a large number of cylinders the closing angle can be reduced in order to save starting air

For slow turning the starting pilot valve will be operated by pulsing signals. The slow turning speed can be adjusted in the WECS-9520 parameters by adopting l th f th l

2.07

length of the pulses

Additionally an air run signal enables to blow the engine with starting air


g

RT-flex, WECS-9520 Starting Valve Control


RT-flex, WECS-9520 Module Redundancy

Redundancy, emergency operation with damaged control parts:parts:

Flex Control Module FCM-20Flex Control Module FCM 20If an FCM-20 fails or being switched off, the corresponding cylinder is cut out and its common functions will fail, all other cylinders remain operative

Any FCM-20 module can be exchanged with the online spare. The respective software and parameters are already stored within the online

d l d ft d l d i ispare module and no software download or reprogramming is necessary

When installing a new FCM-20 module from stock, it must first be installed in the E90 box (Cylinder “0”) as online spare for updating


RT-flex, WECS-9520 System Redundancy

System CAN Bus, Module Bus (CANopen or MODbus) and SSI Bus (CA)Always two busses are active. If one bus is interrupted, shortened or else, the y p , ,second bus is still available for communication. Engine operation is not interrupted

WECS-9520 power supply (E85)All FCM-20 modules have two redundant power suppliesp pp

Bosch pump power supply (E87) (some engine types only)

All Bosch pumps have two redundant power supplies

SensorsSensorsMost of vital sensors and transmitters are existing twice and their mean values are compared and then used for controlling the engine. If one sensor fails, WECS-


9520 indicates the specific sensor failure and continues to work with the remaining one

RT-flex, WECS-9520 Sensor Redundancy

Crank angle sensorIf one of the two crank angle sensors is out of order, WECS-9520 stays operational with the remaining crank angle sensor

But at least one sensor has to be operational !!But at least one sensor has to be operational !!

TDC Pick-upA damaged TDC sensor is indicated by the WECS-9520 monitoring system, but will normally not stop or slow down the engine operation (=> else disconnect sensor)


RT-flex, WECS-9520 Sensor Redundancy

Fuel quantity sensorWith f lt f l tit th di FCM 20 fi dWith a faulty fuel quantity sensor, the corresponding FCM-20 uses a fixed deadtime to calculate the injection begin angle and an artificial fast ramp signal for the fuel quantity, which results in less injected fuel on the affected unit than at normal operationat normal operation

Exhaust valve position sensorEach exhaust valve has two redundant position sensors, RT-flex82 has only one. If both fail, the corresponding FCM-20 controls the exhaust opening and closing valve angles with fixed opening and closing times


RT-flex, WECS-9520 Pump Redundancy

Fuel pumps and actuatorsIf a fuel pump actuator failed, the connected regulating linkage(s) has to be blocked p p , g g g ( )manually in a suitable position. The remaining actuator(s) are compensating as much as possible. The fuel pressure control valve 3.06 limits the rail pressure to 1’050 bar

A damaged fuel pumps need to be lifted up with a tool and the other pumps need to deliver a higher output. Load might be restricted

Servo oil pumpsWith one damaged servo oil pump the engine remains operational, at least at part load

Control oil pumps (some engine types only)p pIf a control oil pump fails, the servo oil rail feeds the control oil circuit via non-return valve 4.29, until the second control oil pump builds up pressure. With both control oil pumps damaged, emergency operation is possible with exclusive oil supply from


p p g , g y p p pp yservo oil rail

RT-flex, WECS-9520 Other Redundancies

Shut down and Emergency StopStopping the engine in case of emergency is done by different ways, where eachStopping the engine in case of emergency is done by different ways, where each one will stop the engine

Triggering the emergency stop valveFuel zero command released by the governory gCutting injectionPulling fuel pumps to zero position

Remote Control / Speed Control SystemWith remote- or speed control out-of-order, the engine can still be operated in fuel control mode from the back-up panel in the engine control room or from thefuel control mode from the back-up panel in the engine control room or from the local control panelIf the speed control is still operational, the WECS-9520 panels allow either fuel control mode or speed control mode from the manual control panels If not onlycontrol mode or speed control mode from the manual control panels. If not, only fuel control possibleThe manual control panels are a part of the WECS-9520 control system, independent from the propulsion system


independent from the propulsion system

Date post:	01-Dec-2015
Category:	Documents
Upload:	tudor-madalin-andrei
View:	849 times
Download:	75 times

40 RT-Flex WECS-9520 Control

Documents