RT Flex Mechanical

RT-fle fl ex me m echa ch anical ni cal fe f eatures tu res

RT-f l ex Tr ai n i n g Mec h an i c al Feat u r es (RT-f l ex Speci Speciff i c Par Par t s onl o nly) y)

Chapter 20

RT-f l ex m ec h an i c al f eat u r es

RT-f l ex s p ec i f i c p ar t s o n l y


RT-f l ex s p ec i f i c p ar t s o n l y


Ov er v i ew , RT-f l ex 50 (Si ze 0) Rail Unit(s)

WECS-9520, E 90 Shipyard Interface Box (SIB) on the free end

WECS-9520, E 95 Cylinder Electronic Unit Terminal boxes

Automatic filter Supply unit

RT-flex mechanical features

Overview, RT-flex60C (Size 1) Rail Unit(s)

WECS-9520, E 90 Shipyard Interface Box (SIB) on the free end

WECS-9520, E 95 Cylinder Electronic Unit Terminal boxes

Automatic filter Supply unit


Overview, RT-flex84 and 96 (Size 4) Rail Unit(s)

WECS-9520, E90 Shipyard Interface Box (SIB) or at the free end (smaller engines)

WECS-9520, E95 Cylinder Electronic Unit Terminal boxes

Supply unit Automatic filter

Control oil Pumps


Rail Unit For engines with more than 7 cylinders, the rail unit is split in two parts.

Both rail-sections (forward/aft) for fuel-, servo- oil are cross connected by high pressure pipes. => Same pressure in the related rails of both halves. WECS-9520 Cylinder-Electronic Unit boxes (E95) are fitted on the outer front side SIB (E90) Box on free end or in the middle of the rail unit depending on the number of cylinders (more than 7 cylinders in the middle) Protection bars


Rail Unit, Size 0


RT-flex58T, MKI

Rail Unit, Size 1

RT-flex58T, MKII


Rail Unit, Size 2


Rail Unit, Size 4


Rail Unit Main Parts Steam

Fuel oi l rail

Fuel oil rail: The fuel rail contains high pressure fuel of ~ 600 - 800 bar delivered by the fuel pumps of the supply unit.

ICU‘s

For each cylinder, there is an Injection Control Unit (ICU). The rail is heated by a trace heating piping system. Servo oil rail: The servo oil rail contains fine filtered (6-micron) high pressure servo oil, ~ 80 - 190 bar, delivered by the servo oil pumps of the supply unit, depending on engine load. For each cylinder there is a Valve Control Unit (VCU).

Control oil rail

Servo oil rail Control oil rail (some engine types only): The control oil rail contains 200 bar control oil (constant pressure) delivered by the control oil pumps. Additional return/leakage piping:  Fuel ICU-leakage pipe  Common servo oil/control oil return pipe  Main bearing oil pipe for exhaust valve actuator pipe (some engine types only)

VCU’s


(fuel) Injection Control Unit (ICU) RT-flex96C


ICU, Size 0


ICU, Size 1


ICU, Size 2


ICU, Size 4

RT-flex mechanical features Fuel quantit y sensor

Servo (cont rol) oil side: The rail valves control the oil flow to the control oil block.

Fuel quantity pis ton

Servo (control) oil side Rail valves

ICU

Servo oil return

Fuel control valves

Fuel side: The fuel control valves are actuated by pistons in the control oil block. There is one valve for each injector. The main body of the ICU includes the injection quantity piston. “Fuel Quantity Sensor” in a housing kept away from the hot block. Control- and fuel oil side are entirely separated from each other. Nevertheless, leakages of both systems have a common drain.

Servo oi l supply

Fuel side

Working principle: Each ICU is pre-controlled by 2 or 3 rail valves to open or close the way for fuel from the rail to the injection nozzles. Fuel for each injection, necessary stroke is calculated and quantified, then injected, measured and corrected for the next injection.


Fuel Nozzle

Fuel nozzle with “venting spiral” (not valid for “MKI”)

Opening pressure 375 bar


(exhaust) Valve Control Unit (VCU) Valid for flex 50B, 58T (MKII), 60C (MKII), 68B, 84T-D


VCU Valid for flex 58T (MKI), 60C (MKI), 96C-B


To exhaust valve 3/2 way valve

VCU (MKI, 96C-B)

The servo oil supply from the servo oil rail to the 3/2 way valve is done via connecting element. The 3/2 way valve is pre-controlled by a rail valve (same type as for ICU).

Rail valve Main bearing oil supply

VCU cylinder and piston

The servo oil return pipe has a back pressure of ~2-3 bar to dampen pressure peaks. To the upper part of the VCU/actuator pipe, there is a main bearing oil inlet via a non-return valve, in order to fill up the oil losses through the orifice in the exhaust valve drive.

Connecting element Servo oil return

Shown for flex 58T (MKI), 60C (MKI), 96C-B


VCU (50B, “ MK II” , 68B, 84T-D)

Rail Valve To exhaust valve drive

3/2 way valve

Valid for flex 50B, 58T (MKII), 60C (MKII), 68B, 84T-D

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.

Servo o il r eturn

VCU piston

Servo oil suppl y

HP-hoses to/ from ICU


Shown for RT-flex96C-B

Rai l Un i t Pi p i n g


Shown for RT-flex96C-B

Rai l Un i t Pi p i n g


Rai l Un i t Pi p i n g , Si ze 0

ICU Trace heating Fuel oil rail Fuel overpressure regulating valve

Servo oil rail

VCU Servo oil return pipe


Rail Unit Piping, Size 0 Fuel oil rail Trace heating

ICU

Servo oil rail

VCU

Servo oil return pipe

Rail Unit Piping, Size 1 MK I

RT-flex mechanical features VCUs ICUs

Fuel rail

Fuel rail: The fuel rail contains high pressure fuel of ~ 600 -900 bar delivered by the fuel pumps of the supply unit during engine operation. The rail pressure is regulated depending on engine load. For each cylinder, there is an Injection Control Unit (ICU) installed on the fuel rail. The ICUs are actuated by help of control oil pressure. WECS is activating the ICUs for injection control. The rail is heated by a trace heating piping system.

Servo oil return pipe

Main bearing oil supply

Servo oil rail Control oil supply rail Control oil return rail

Servo oil rail: The servo oil rail contains fine filtered (6-micron) high pressure servo oil, ~ 80-190 bar, delivered by the servo oil pumps of the supply unit, depending on engine load. For each cylinder there is a Valve Control Unit / exhaust valve actuator (VCU) installed on the servo oil rail. WECS is activating the VCUs for exhaust valve control.



Additional piping in previous design: 

ICU fuel drain pipe. (constant orifice leakage drained to fuel return to booster unit)



Fuel leakage drain (ICU internal leakage or injection pipe leakage)



Control oil supply rail to supply actuating control oil to ICUs.



Separate control oil return rail.



Main bearing oil supply to VCU (refilling of drained oil through constant orifice in exhaust valve drive)

Trace heating

ICU fuel drain pipe Fuel leakage drain to overflow tank


RT-flex mechanical features Control oil pumps SHD-valve arrangement

Control oil supply rail

Control oil pumps: - Two electrically driven control oil pumps supply control oil with constant pressure of 200Bar to the control oil supply rail. Overpressure regulating valve: - Similar function as the valve used for new design, but the SHD function is not included. (fuel drained to overflow tank)

Control oil return rail

SHD-valve arrangement: - The SHD solenoid valve (energised by Safety System) enables control air to the SHD-servo, that activates the SHD-valve itself to depressurize the fuel system. (fuel drained to overflow tank) Overpressure regulating valve


Rail Unit Piping, Size 1 MK II

Fuel oil rail: The fuel rail contains high pressure fuel of ~ 600 -900 bar delivered by the fuel pumps of the supply unit during engine operation. The rail pressure is regulated ICUs depending on engine load. For each cylinder, there is an Injection Control Unit (ICU) installed on the fuel rail. The ICUs are actuated by help of servo oil pressure via hydraulic HP-hoses. WECS is activating the ICUs for injection control. Fuel rail The rail is heated by a trace heating piping system. Servo oil rail: The servo oil rail contains fine filtered (6micron) high pressure servo oil, ~ 80-190 bar, delivered by the servo oil pumps of the supply unit, depending on engine load. For each cylinder there is a Valve Control Unit / exhaust valve actuator installed on the servo oil rail. WECS is activating the VCUs for exhaust valve control. The high pressure rails of new design are made of single pipes. The ones of old design rail of rail pipe sections.

VCUs

Servo oil rail


Rail Unit Piping, Size 1 MK II

Additional return/leakage piping:

Fuel leakage pipe

One fuel leakage pipe (back to overflow tank)  One common servo oil return pipe (back to crankcase)  Trace heating (steam or thermo oil) 

Safety valve

Fuel system overpressure valves: Servo oil return pipe 



SHD and overpressure regulating valve. Opening pressure approx. 1050bar for overpressure regulation. The SHD-solenoid is activated by Safety System to depressurize the fuel system (fuel drained to return pipe to booster unit). Safety valve. Opening pressure 1250bar. (fuel drained to overflow tank).

Trace heating

SHD and overpressure regulating valve


Rail Unit Piping, Size 4 Control oil high pressure hoses Trace heating Fuel oil rail ICU and injection high pressure pipe leakage drain pipe (connected to leakage collector => Alarm to AMS)

Servo oil rail

Main bearing oil supply pipe for upper side of VCU (flex96C-B only)

Control oil rail

Servo oil (and control oil) common return pipe


Rail Unit Piping

At each inlet, there are shut-off valves, in order to isolate individual HP-pipes in case of leakages. Fuel-, servo- and control oil inlet to the rails are between the two rail unit halves (if more than 7 cylinders). For redundancy reasons there are for each system two rising pipes connected to the two rail unit halves. The cross-connection high pressure pipes enable a direct connection between each rail for 

pressure equalization



if one HP pipe is broken, it can be shut-off on both ends and the remaining one feeds both rails


Rail Unit Piping

Rail unit general drain piping. Possible leaks of fuel, oil and water are collected for each rail => Alarm to Alarm System „Rail Unit (FWD), General Leak“. The leakage is drained to the sludge tank.


Fuel Rail Pipe Shown for RT-flex96C

The fuel rail pipe is made of one piece.

The bore has a shape of a “peanut”.


Rail Valves


Rail Valve RV-2 Injection / Valve open

Rail valve are quick acting 3/2-way solenoid valves. Each cylinder unit has four rail valves. Three of them are pre-controlling an ICU, one of them is pre-controlling the VCU. Flex50 has only two rail valves per ICU. Following an injection/return- or open/close command of WECS-9520, the corresponding coils are energized for a very short time (normal operation ~1 ms, max. 4.5 ms), but with a high current impulse (~50-60A). Iron core This makes the valve spindle move towards the energized coil (~0.3 mm stroke). Valve spindle The high current impulse and the short travel of the valve spindle enable a very short actuation time, which is indispensable for precise injection- or exhaust valve control.

The rail valves are non-serviceable. Nevertheless, if dirt particles are suspected to influence proper operation, the valves can be opened and blown out by air.

Control oil inlet Inlet/outlet to ICU/VCU Outlet to return pipe

Coils

Pay attention to the assembly position of valve spindle. Electric sockets No injection / Valve close


Exhaust Valve Drive (50-B, MK I)


Main differences to a conventional RTA-valve dr ive: 

The exhaust valve is actuated by a double piston drive, in order to save oil volume



Two redundant exhaust valve stroke sensors for monitoring



One measuring cone for stroke sensors





Air spring piston runs directly in the housing. The disc spring package is dampening opening stroke in case of low air spring pressure

Exhaust Valve Drive (60C) Damper

Orifice

Oil inlet from exhaust valve actuator pi pe

Double pisto n drive Two exhaust valve strok e sensors Joint ring Measuring cone Air spring pist on Disc spring package Exhaust valve spindle


Exhaust Valve Drive (58T-B, MK I)


Exhaust Valve Drive (60C, MK I)


Main diff erences to a conventio nal RTA-valve drive: 

The exhaust valve is actuated by a double piston drive, in order to save oil volume



Two redundant exhaust valve stroke sensors for monitoring



One measuring cone for stroke sensors





Air spring piston runs directly in the housing. The disc spring package is dampening opening stroke in case of low air spring pressure


Orifice

Oil inl et fro m exhaust valve actuator pi pe

Double pisto n drive

Measuring cone Two exhaust valve strok e sensors Air spring pist on Disc sp ring package Exhaust valve spindl e

Joint ring



Oil inlet from exhaust valve actuator pi pe

Double pisto n drive

Measuring cone Two exhaust valve strok e sensors Air spring pist on Disc spring package Exhaust valve spindl e

Orifice

Thrust piece


Supply Unit Drive, Size 0

Single lobe drive


RT-flex58T-B


RT-flex60C








Supply Unit Drive Supply unit gearwheel

3-lobe cams

The supply unit is driven by the crankshaft, via two intermediate gearwheels.

Drawn for Size 4

3-lobe cams are mounted to the camshaft (size 0 with single lobe mono block camshaft and size 3 with 2-lobe mono block camshaft). The servo oil pumps are driven by individual pinions, having a „mechanical fuse“ (reduced diameter in pinion), in order to protect the geardrive in case of a pump seizure. The servo oil pump gearwheel is hydraulically fitted as well. Since the supply unit, i.e. fuel pumps and servo oil pumps have no timing, means they just supply fuel or oil, the camshaft doesn‘t have to have a determined position compared to crankshaft. However the position of the cams relative to each other must be respected.

Camshaft bearing covers

2nd intermediate gearwheel

Servo oil pump drive gearwheel and pinions


Supply Unit, Size 0


Supply Unit, Size 1

RT-flex60

RT-flex58T


Supply Unit, Size 2


Supply Unit, Size 3


Supply Unit, Size 4

RT-flex mechanical features Fuel side: The „jerk-type“ fuel oil pumps deliver fuel into the intermediate accumulator. To keep the rail pressure (600 - 900 bar), the pump flow rate is regulated via regulating linkage and el. actuators, by pressure set point signals from WECS.

Supply Unit Fuel intermediate accumulator Fuel outlet to rail

Electric actuators Servo oil collector block

From the accumulator there are two outlets, connecting the accumulator to the fuel rail via two rising pipes. Servo oil side: The servo oil pumps are made by Dynex or Bosch. They deliver servo oil into servo oil collector block with a pressure of ~ 80 -190 bar. There are two outlets from the collector block, connecting to the servo oil rail via two rising pipes. The number of fuel- and servo oil pumps depends on the number of cylinders.

Servo oil outlet to rail

Servo oil pumps (shown here as „Bosch“)

Fuel pumps

2nd intermediate gearwheel

RT-flex mechanical features Shutdown & overpressure regulating valve

Supply Unit, size 4

Shutdown solenoid valve

Fuel drain

Fuel pressure retaining valve

Fuel inlet from booster unit

Fuel return to mixing tank

Intermediate accumulator with two safety valves (1’250 bar).


Fuel Pump

RT-flex mechanical features Fuel pumps: The jerk-type fuel pumps deliver a variable quantity of fuel to the intermediate accumulator and fuel rail, in order to maintain the demanded rail pressure. They do not have any timing. To change the feed quantity, the pump plunger is turned by the regulating rack. The roller guide/roller assembly and regulating sleeve are lubricated by main bearing oil via a double orifice.

Fuel Pump Buffer space Non return valve Pump cylinder

Pump cover

Pump plunger Regulating sleeve

Regulating rack

Compression spring

Roller guide

Roller

Upper housing

Lower housing


Fuel Pump


Fuel Pump

Plunger positi on at regulating linkage position: Pos: 0 No deliv ery

Pos: 5 Half delivery

Pos: 10 Full delivery

RT-flex mechanical features Electric fuel pump actuators

Regulating Linkage Fuel pump regulating l inkage: The regulating linkage is moved by Woodward (ProAct IV) electric actuators. They receive a position set point signal from WECS. One actuator controls two fuel pumps (the arrangement of actuators can differ among engine cylinder numbers).

Local position indication (0-10). No load indic ator !!

The torque from linkage shaft to fork lever is transmitted in both directions via torsional springs. If a regulating rack of a pump is stuck for some reason, the springs will compensate, so the other pump can still be regulated.

Fork lever Additional spring to push the rack, in case of failure, to full position

Torsional springs


Supply Unit, Servo Oil (96C)

Servo oil pumps arrangement: The servo oil pumps supply oil to the collector block, which has two high pressure outlet pipes to the servo oil rail. A safety valve limits the max. pressure to 230 bar. The number of servo oil pumps depends on the number of cylinders. If one pump fails, the engine can still be operated. Flow sensor Safety valve

Non return valves at each inlet

High pressure pipes Collector Block

Servo oil pumps

Oil supply

Bosch pumps arrangement (some engines only).

Dynex pumps arrangement

RT-flex mechanical features Suction port

Compensator valve with solenoid

HP-outlet (Inch-type thread!)

Servo Oil Pump „ Dynex“


Servo Oil Pump „ Dynex“

RT-flex mechanical features Servo Oil Pump „ Bosch“ , flex96C-B The Bosch servo oil pumps are axial piston swashplate type pumps. They supply oil to the collector block and via two high pressure pipes to the servo oil rail. A safety valve limits the max. pressure to 230 bar. The number of servo oil pumps depends on the number of cylinders. If one pump fails, the engine can still be operated at full load. When the engine turning direction is reversed, the swash-plate of the pumps needs to be reversed as well. Control oil is used to move the swash-plate to position.

RT-flex mechanical features Case drain Swashplate angle encoder Visual indication

Servo Oil Pump „ Bosch“ Control oil inlet

Leak oil return

High pressure outlet Non return Valve / anti cavitation port

Proportional valve solenoidvalves

Proportional valve position transmitter

Proportional valve

HP-outlet pressure transmitter

Main oil inlet

Anti cavitation inlet (from servo oil main supply pipe)


Servo Oil Pump „ Bosch“

The Bosch-Rexroth pumps have its own regulating system, getting pressure setpoint signals and ahead/astern signals from WECS. The anti-cavitation port avoids cavitation in the pump body, if a pump does not move the swashplate to the appropriate engine running direction. (pump tries to suck in from HP-outlet pipe). In such a case, the non-return valve at anti-cavitation port opens. Servo oil from main supply pipe is sucked in via anticavitation port and delivered out again via main inlet. The oil will thus flow "idle" through the pump. This is default in case of black out, the swashplate swings to ASTERN position to prevent servo oil overpressure due to windmilling engine without servo oil consumption.

B,B1 SB S P,SP Rkv R(L)

Pressure Port Anti Cavitation Port Suction Port Control Pressure Port Pilot Fluid Drain Return (Aeration)

SAE 1 1/2 " SAE 2 " SAE 3 " M18x1.5 M22x1.5 M42x2


RT-flex58T, MK1

Control Oil Pumps (Size 1, MK I)


Control Oil Pumps, Size 4

HP-Inlets from pumps Drain valve for leakage (with orifice)

3 shut of valves for outlets

“Kraus & Wimmer”

2 Pressure retaining valves 2 Overpressure relief valves

Pressure transmitter for leak detection (signal to Alarm System)

2 (3) HP-outlets for double wall pipes -> control oil rails

“Bucher”


Service Pump


The automatic filter unit filters the servo (and control-) oil to 6 μm. The by-pass filter has a mesh size of 36 μm. The filter "sludge" goes back to the crankcase.

Automatic Filter


Crank Angle Sensor (CA)

The crank angle sensors are located on the free end of the crankshaft (or Geislinger Damper).

The crank angle signal is absolutely indispensable for engine operation. At least one of the sensors must be working. If one fails, WECS-9520 can detect the failure and will keep working with the healthy signal (plausibility check). In case both sensors fail, the engine will stop without delay.

There is no emergency operation possible without at least one CA sensor!


CA-Sensor

They are separated from the crankshaft by a special coupling. They create an exact digital signal of the actual crankshaft position (0….360°) The CA sensors have a resolution of 0.1° The spring loaded coupling absorbs all longitudinal and axial movement of the crankshaft. It drives a shaft which is supported by two ball bearings. The bearings are oil lubricated. From the shaft a toothed belt drives each sensor. Shielded BUS cables transmit the signals to the WECS-9520 control.

CA-Sensors are delivered in a box

CA-Sensor, complete with holder and cable.


CA-Sensor

RT Flex Mechanical

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