© Wärtsilä Land & Sea Academy Page 1 Chapter 30 30-Apr-09 RT-flex Control Elements RT-flex Training Function of the different Hydraulic- and Pneumatic Components Chapter 30
© Wärtsilä Land & Sea Academy Page 1 Chapter 30 30-Apr-09
RT-flex Control Elements
RT-flex Training
Function of the different Hydraulic- and Pneumatic
Components
Chapter 30
© Wärtsilä Land & Sea Academy Page 2 Chapter 30 30-Apr-09
RT-flex Control Elements Overview
Injection ControlExhaust Valve Control
Servo oil pressure controlFuel pressure control
Control oil pumps control
Valve stroke measurementICU stroke measurement
Crank angle detection
Auxiliary Functions
Main FunctionsStarting Valve Control
© Wärtsilä Land & Sea Academy Page 3 Chapter 30 30-Apr-09
RT-flex Control Elements Injection Control Unit (ICU)
The ICU controls the timing and volume of the injection.
Each ICU has 3 (or 2) “rail valves” to pre- control its own “injection control valve”. The injection control valves control the movement of the “fuel quantity piston”.
© Wärtsilä Land & Sea Academy Page 4 Chapter 30 30-Apr-09
RT-flex Control Elements ICU
WECS-9520 controlServo (control) oil
supply 200 bar
© Wärtsilä Land & Sea Academy Page 5 Chapter 30 30-Apr-09
RT-flex Control Elements ICU
© Wärtsilä Land & Sea Academy Page 6 Chapter 30 30-Apr-09
RT-flex Control Elements ICU Cross-Section
© Wärtsilä Land & Sea Academy Page 7 Chapter 30 30-Apr-09
RT-flex Control Elements ICU
Fuel rail
Servo rail
Rail valves
Injection control valves
Fuel quantity piston
Fuel quantity sensor
Fuel nozzles
(Size 4: Control rail)
© Wärtsilä Land & Sea Academy Page 9 Chapter 30 30-Apr-09
RT-flex Control Elements ICU, new leak drain (96C-B)
New piping layout separates leak drain from injection pipes and from ICU internals.
Inspection plug for visual check of leak.
© Wärtsilä Land & Sea Academy Page 10 Chapter 30 30-Apr-09
RT-flex Control ElementsFuel overpressure regulating valve:
In case of the fuel pressure in intermediate accumulator pipe or fuel rail pipe rises to ~1’050 bar, the overpressure regulating valve releases fuel to the fuel return line. The opening pressure is pre-adjusted by valve manufacturer. Shims are used to give the right position to the knurled screw, means if the screw is fully screwed down to shims, 1’050 bar are set
for new building RT-flex84T-D and 96C-Bengines’ opening pressure is 950 barfor in-service RT-flex84T-D and 96C-Bsee Service Letter RT-flex-07/07
The min. opening pressure, means when knurled screw is screwed fully out, is around 500 bar (engine still operational).During normal operation, main bearing oil pressure keeps the valve closed. When the opening fuel pressure is reached, main bearing oil is released, pressure above piston drops and fuel is released.
Fuel Overpressure Regulating Valve
© Wärtsilä Land & Sea Academy Page 11 Chapter 30 30-Apr-09
RT-flex Control Elements Shutdown Valve
Shutdown Solenoid valve
MB-oil supply
Oil filter
Lever for manual de- pressurising for mainte- nance work
Piston
Solenoid valve leak drainEngine shutdown function:
A shutdown is initiated by energizing the solenoid valve (energized from safety system, not WECS). In this way, main bearing oil pressure above piston is released, resulting in fuel pressure drop down engine stops
© Wärtsilä Land & Sea Academy Page 12 Chapter 30 30-Apr-09
RT-flex Control Elements (exhaust) Valve Control Unit (VCU)
© Wärtsilä Land & Sea Academy Page 13 Chapter 30 30-Apr-09
RT-flex Control Elements VCU
© Wärtsilä Land & Sea Academy Page 14 Chapter 30 30-Apr-09
RT-flex Control Elements VCU (general working principle)
The valve control unit is pre-controlled by the rail valve. At a certain crank angle, it gets an „exhaust valve open“ impulse signal from WECS. Servo oil flows via rail valve to the lower side of the 3/2 way valve spindle and moves it up. Thus, servo oil flow to the VCU-cylinder is enabled. Via bores in the VCU-piston, oil flows into the lower side of the piston and moves it towards the upper end.
the exhaust valve opens
At another calculated angle, WECS-9520 transmits an „exhaust valve close“ signal to the rail valve. The 3/2 way valve spindle moves down, releasing the oil from the VCU-piston underside allowing the oil volume in the exhaust valve to return to the VCU. The servo oil underneath the VCU piston is drained to the servo oil return pipe.
the exhaust valve is closing
Due to certain control bores or chamfers, the VCU- piston has a progressive movement. Means, it starts to move fast and slows down, as it gets closer to the end stop. The losses of servo oil through the orifice on the exhaust valve side is compensated in the VCU with servo- or main bearing oil.
Rail valve
VCU piston
3/2 way valve spindle
Actuator pipe withmain bearing oil
The servo oil return pipe has a back pressure of ~2-3 bar, in order to dampen pressure peaks.
© Wärtsilä Land & Sea Academy Page 15 Chapter 30 30-Apr-09
RT-flex Control Elements VCU
The servo oil supply from the servo oil rail is done via connecting element.
To compensate the intended oil loss through the constant orifice in the exhaust valve drive upper housing, there is a main bearing oil inlet via a non-return valve.
VCU cylinder
Main bearing oilsupply, (non returnvalve at inlet)
3/2 way valve
Connecting element
Servo oil return/outlet
To exhaust valve drive
Filter insert
Rail valve
Valid for flex 58T (MKI), 60C (MKI), 96C-B
© Wärtsilä Land & Sea Academy Page 16 Chapter 30 30-Apr-09
RT-flex Control Elements VCURail Valve
3/2 way valve
VCU piston
Servo oil supply
To exhaust valve drive
Servo oil return
HP-hoses to/from ICU
The VCU sits directly on the servo rail.
In order to refill the intended oil loss through the constant orifice in the exhaust valve drive upper housing, there is an internal orifice to the upper part of the VCU/actuator pipe.
Valid for flex 50B, 58T (MKII), 60C (MKII), 68B, 84T-D
© Wärtsilä Land & Sea Academy Page 17 Chapter 30 30-Apr-09
RT-flex Control Elements VCU
Servo rail
Rail valve Slide rod Piston
Position sensor
Spring air
Exhaust valve
*) internal from servo rail or external from lube oil
Oil supply *)
© Wärtsilä Land & Sea Academy Page 19 Chapter 30 30-Apr-09
RT-flex Control Elements Automatic Filter
Servo oil and control oil is fine filtered before it enters the pumps and hydraulics. The automatic filter has cartridges of nominal 6 µm. There is an bypass filter of 36 µm mesh size.
The reason for filtering is to increase the lifetime and safety margin of all hydraulic components.
Control box with indications
© Wärtsilä Land & Sea Academy Page 20 Chapter 30 30-Apr-09
RT-flex Control Elements Automatic Filter
The back flushing is automatically initiated by the control box either
A) standard: Time controlled (after 1 hour)
B) or: if the differential pressure across the filter becomes too high (0.35 bar)
The filter "sludge" goes back to the crankcase. It is filtered system oil which is clean enough for normal use.
In the filter control box the back flushing is initiated either by time or differential pressure. Flushing cycles are counted. Failure messages are generated if necessary (Over current, differential pressure high etc…)
Inside the box there are switches/buttons to switch from “Operation” to “Adjust”. For detailed information please consult filter maker’s manuals.
© Wärtsilä Land & Sea Academy Page 21 Chapter 30 30-Apr-09
RT-flex Control Elements Air system
Air is used for:
Actuation of automatic start valve
Starting of engine
Spring air supply
(Oil mist detector)
Flushing of automatic filter for servo and control oil
(OMD)(SHD valve)
© Wärtsilä Land & Sea Academy Page 22 Chapter 30 30-Apr-09
RT-flex Control Elements Air supply
From starting air bottles (30 bar)
From control air supply (7-9 bar)
To air springs To automatic main starting valve
through turning gear
(OMD)(SHD valve)
© Wärtsilä Land & Sea Academy Page 23 Chapter 30 30-Apr-09
RT-flex Control Elements Control air supply unit
© Wärtsilä Land & Sea Academy Page 24 Chapter 30 30-Apr-09
RT-flex Control Elements Air system (size 0)
Air is used for:
Actuation of automatic start valve
Starting of engine
Spring air supply
(Oil mist detector)
Flushing of automatic filter for servo and control oil
© Wärtsilä Land & Sea Academy Page 25 Chapter 30 30-Apr-09
RT-flex Control Elements Air supply (size 0)
From control air supply (7-9 bar)
To air springs and automatic main starting valve through turning gear
© Wärtsilä Land & Sea Academy Page 26 Chapter 30 30-Apr-09
RT-flex Control Elements Main starting valve
© Wärtsilä Land & Sea Academy Page 27 Chapter 30 30-Apr-09
RT-flex Control Elements Starting air