Sultzer Common Rail

8/6/2019 Sultzer Common Rail

1/9

1 Wrtsil Corporation, January 2004

Kaspar AeberliDirector, Marketing & Sales Support, Marine

Wrtsil Switzerland Ltd, Winterthur

Summary

Common-rail fuel injection, made possible by fully-integrated electronic control, is a major milestone in the developmentof large marine diesel engines. The combination of common rail and electronic control offers unprecedented flexibility ofoperation which opens up further avenues in engine development to meet market requirements for ship propulsion now and

in the future.The first series-built low-speed engine with electronically-controlled common-rail fuel injection has been in service fortwo years with excellent results. Further engines are being ordered by shipowners who recognise that common-rail fuelinjection is a desirable development.

Today common-rail technology provides benefits in smokeless operation at all operating speeds, lower fuel consumption,reduced maintenance costs and lower steady running speeds for better manoeuvring. Further progress can be expected alongthese lines over the coming years.

* This paper is based on papers and presentations at the International Symposium on Combustion Engines and MarineEngineering (ISCEM 2003), Busan, Korea, 2224 October 2003, and the 4th International Ship Propulsion SystemsConference, Manchester, 1012 November 2003. Statistics are updated to January 2004.

Common Rail: The Way Ahead for Ship Propulsion

Fig. 1: The first nine-cylinderSulzer RT-flex60C engine

during its official shop test atHSD Engine Co Ltd, Korea.

[04#007]


2/9


Introduction

Common-rail fuel injection is now a practical propositionfor large, low-speed marine diesel engines. The first suchSulzer RT-flex engine has been at sea for than two years

with excellent service experience and the system is tobe employed in the most powerful marine engines builttoday.

Although common-rail fuel injection is certainly not anew idea, it has only become truly practical now throughthe use of fully-integrated electronic control whichallows full use to be made of the flexibility possible withcommon-rail injection.

The traditional camshaft has the considerablelimitation of fixed timing given mechanically by the cams.

Although Sulzer low-speed engines have long had thebenefits of double valve-controlled fuel injection pumps

with variable injection timing (VIT), and a degree ofvariable exhaust valve timing being achieved hydraulically

in the VEC system, the variation in timing so obtained hasbeen very limited.

The change to electronically-controlled common-railsystems has been made to ensure that the timing, rate andpressure of fuel injection and the exhaust valve operationare fully controllable, allowing patterns of operation whichcannot be achieved by purely mechanical systems.

The common-rail concept was adopted because it hasthe advantage that the functions of pumping and injectioncontrol are separated. This allows a straightforwardapproach to the mechanical and hydraulic aspects ofthe design, with a steady generation of fuel oil supply at

the desired pressure ready for injection. The common-rail concept also has the unique advantage that it allowsthe fuel injection valves to be individually controlled.Usually there are three fuel injection valves in eachcylinder cover, and in the Sulzer RT-flex engines they are

operated mostly in unison but under certain circumstancesthey are operated separately for optimum combustionperformance.

The common-rail concept thus provides an ideal basisfor the application of a fully-integrated electronic control.The combined flexibilities of common rail and electroniccontrol provide improved low-speed operation, engineacceleration, balance between cylinders, load control,and longer times between overhauls. They also ensure

better combustion at all operating speeds and loads,giving benefits in lower fuel consumption and lowerexhaust emissions in terms of both smokeless operationat all operating speeds and less NO

Xemissions. Engine

diagnostics are built into the system, improving enginemonitoring and reliability.

As the common-rail system is built specifically forreliable operation on heavy fuel oil, it detracts nothingfrom the well-established economy of low-speed marinediesel engines but rather opens up new possibilities foreven better economy, ease of operation, reliability, timesbetween overhauls and lower exhaust emissions.

It is ten years since development of the Sulzer RT-flex

common-rail system began and more than 20 years sincethe first tests were made with electronically-controlled fuelinjection in Winterthur, Switzerland.

The early camshaftless systems developed for Sulzerengines used individual, hydraulically-operated fuelinjection pumps. However the change in injection conceptfrom the individual, hydraulically-operated fuel injectionpumps to a common-rail system in 1993 was madebecause the system with individual pumps did not offerpotential for further technological development despiteit having integral electronic control. Electronic control

was found to be insufficient by itself, a new fuel injection

concept was recognised as essential. Common rail wasseen as the road ahead and it is applied in Sulzer RT-flexengines.

To summarise, common rail is seen to qualify as the

Fig. 2: Section of rail unit for a Sulzer RT-flex96C engine.The fuel rail is on the left and the servo oil rail is on the right,with control units superimposed on both.[03#016]

Fig. 3: Supply unit on a 7RT-flex60C engine with the fuelpumps in a Vee-form arrangement on the right and servo oilpumps to the left of the gear drive.

[03#039]


3/9


way ahead for the further development of low-speedmarine engines because: The technical concept is well founded Reliability is becoming well proven first engine

exceeding 12,000 running hours More engines are already in service Sulzer RT-flex engines are available for your projects

today with powers of 565080,080 kW Market demand is clear already confirmed orders for

61 engines Benefits available today are worthwhile with the current

execution Future potential exists for continuing development

Well-founded technical concept

Compared to the conventional, mechanically-controlledlow-speed two-stroke marine engine, the Sulzer RT-flexengine is provided with unique features through the fully-integrated electronic control of fuel injection and exhaustvalve actuation [1]. This makes it possible to replacevarious mechanical parts: the camshaft and its gear drive,the complete fuel injection pump units including theexhaust valve actuator pumps and reversing servomotors,and all their related mechanical control gear.

These parts are replaced by four principal elementsin the Sulzer RT-flex system: the rail unit along the sideof the cylinders (Fig. 2), the supply unit on the side ofthe engine (Fig. 3), a filter unit for the servo oil, and the

integrated electronic control system.The common rail is a pipe running the length of the

engine just below the cylinder cover level. Together withrelated pipework, it is neatly enclosed with ready access

Fig. 4: Side elevation of the 12-cylinder Sulzer RT-flex96C engine showing the supply unit in the middle and the rail units near thecylinder tops. The engine is some 22.6m long..[03#085]

Fig. 5: Test rig for the common-rail system of the RT-flex96Cengine. An injection control unit (ICU) is mounted on acommon rail which is of the length for six cylinders. To the leftof the ICU are the three fuel injection valves for one enginecylinder.[03#120]


4/9


from above and the side. The common rail providesstorage volume for the fuel oil, and has provision fordamping pressure waves. There is no need for energystorage under gas pressure. The volume of the common-

rail system and the supply rate from the fuel supply pumpsare such that the rail pressure is very stable with negligiblepressure drop after each injection.

The common rail is fed with heated fuel oil at the usualhigh pressure, up to 1000 bar, ready for injection. Thesupply unit has a number of high-pressure pumps runningon multi-lobe cams with a speed-increasing gear. Thepumps have suction control to regulate the fuel deliveryvolume according to engine requirements.

Although the pumps run on a camshaft, it cannotbe compared with the traditional engine camshaft. It isvery short and of much smaller diameter, and is quite

differently loaded as there is no sudden, jerk action butrather the pump plungers have a steady reciprocatingmotion. With multi-lobe cams and the speed-increasinggear drive, each fuel supply pump makes several strokesduring each crankshaft revolution. The result is a compactsupply unit.

Servo oil for injection control and exhaust valveactuation is provided at a pressure of 200 bar by a numberof hydraulic pumps also on the supply unit. They deliverto a second common rail alongside the fuel rail.

For the first engines, the supply unit is arranged low onthe manifold side but subsequent engines have it higheron the opposite side. This keeps the engine footprint

small so that the engines can be located far aft in shipswith fine afterbodies.

Fuel is delivered from the common rail through aseparate injection control unit for each engine cylinder to

standard fuel injection valves (Fig. 5). The control units,using quick-acting Sulzer rail valves, regulate the timing offuel injection, control the volume of fuel injected, and setthe shape of the injection pattern. The three fuel injectionvalves in each cylinder cover are separately controlled sothat, although they normally act in unison, they can alsobe programmed to operate separately as necessary.

The common-rail system is purpose-built for operationon just the same grades of heavy fuel oil as are alreadystandard for Sulzer RTA-series engines. For this reason,the RT-flex system incorporates certain design features notseen in other common-rail engines using middle-distillatediesel oils. The key point is that, in the RT-flex system,the heated heavy fuel oil is kept away from the precisionquick-acting rail valves.

The exhaust valves are operated in much the same wayas in existing Sulzer RTA engines by a hydraulic pushrodbut with the actuating energy now coming from the servooil rail. The electronically-controlled actuating unit foreach cylinder gives full flexibility for valve opening andclosing patterns. This unit utilises exactly the same Sulzerrail valves as are used for controlling fuel injection.

Being proven in service

Although engine testing of the Sulzer RT-flex systembegan in June 1998, the real proof of the capability of theelectronically-controlled common-rail system has come

with the first series-built RT-flex engine [2]. Enteringservice in September 2001, this engine was built tooperate using only the electronically-controlled common-rail system with no alternative. It went to sea as a fullyindustrialised product, ready for continuous heavy-dutycommercial operation. It achieved this performance with

very good success.The engine is a Sulzer 6RT-flex58T-B, of 11,275 kWat 93 rev/min, and is installed in the bulk carrier GypsumCentennial. By the end of 2003, it had accumulated morethan 12,000 running hours. The service experience of thisengine has already been reported [3, 4, 5].

One key point from the operation of the RT-flexengine has been that the ships engineers quickly becamecomfortable operating the engine, and were onlyaccompanied by a Wrtsil engineer up to the end of May2002.

Throughout its operation, the service experiencehas been very good. Although there were a number of

teething problems during the first few months, theyhave mostly been remedied or new components are underdevelopment.

Even when there were problems, in most cases they

Fig. 6: Test rig for a fuel supply pump of the RT-flex96Cengine. To the left of the vertical pump is the fuel collector.The pump delivers fuel to the common-rail test rig shown in

figure 5.[03#121]


5/9


did not interfere with normal ship operation as theycaused either just an alarm signal or the engine to slowdown. Some faults were rectified during normal scheduledengine halts while the majority, concerning common-rail and electronic components, could be rectified bybriefly slowing the engine and replacing components.Six unplanned shutdowns occurred in the first couple of

months operation, but since then there has only been asingle stoppage.The fact that the whole design of the common-rail

system was made in-house proved invaluable whentroubleshooting problems. In-house knowledge allowsquick diagnosis of problems and prompt identification ofsuitable remedies.

By the end of 2003, a total of four ships had beendelivered with Sulzer RT-flex engines (Figs. 7 to 10). Theother three are: The Aframax tanker Sea Ladyin Japan entered service

in August 2003 with a 6RT-flex58T-B engine The multi-purpose carrier Wladyslaw Orkan built in

China was delivered in November 2003 witha 7RT-flex60C engine

The reefer Carmel Ecofresh, also with a 7RT-flex60C,was delivered from Portugal also in November 2003.

Overall the service experience with these RT-flexengines has been very satisfactory.

In demand for newbuildings

Sulzer RT-flex engines have been very well received byshipowners. The research engine and the first series-built

engine attracted their interest right from the outset.By January 2004, a total of 61 Sulzer RT-flex engineshad been built or were on order, aggregating 2.26 millionkW (3.08 million bhp), see Table 1.

The concept has therefore been extended to otherSulzer low-speed engine types (Fig. 11). The SulzerRT-flex58T-B and RT-flex60C are now in service. Thenext type to be built will be the largest bore size, the SulzerRT-flex96C which will also be developed in a 14-cylinderversion to give 80,080 kW (108,920 bhp) for jumbocontainer liners. The RT-flex84T-D will be specifically forULCCs and VLCCs, and the RT-flex68T-B will also beincluded. The smallest RT-flex engine is the new

RT-flex50 currently under development which extends therange down to 5650 kW (7700 bhp).

With the increasing numbers of RT-flex engines beingordered, their manufacture is also being extended to more

Fig. 7: The bulk carrierGypsum Centennial, Sulzer6RT-flex58T-B.[01#148]

Fig. 8: Aframax tankerSea Lady, Sulzer 6RT-flex58T-B.[03#105]

Fig. 9: Multi-purpose carrierWladyslaw Orkan, Sulzer7RT-flex60C.[03#115]

Fig. 10: ReeferCarmel Ecofresh, Sulzer 7RT-flex60C.[04#002]


6/9


factories. So far, they have been, or will be manufacturedin six factories in four countries; namely Wrtsils ownfactory at Trieste, Italy, and five licensees in Korea, Japanand China PRC.

Benefits for shipowners

The benefits of the electronically-controlled common-rail

systems of Sulzer RT-flex engines are outlined above in theIntroduction. Attention here is focused on the particularaspects of fuel consumption, slow-running behaviour andexhaust emissions.

Although Sulzer RT-flex engines can be applied toadvantage in any ship types their benefits will carrydifferent weight in different ship types according to theirtypes of operation and their owners priorities.

For example, the very slow running ability and reducedpart-load fuel consumption are expected to be particularlyattractive for very large and ultra large crude oil carriers(VLCC and ULCC), while their smokeless operation

might be highlighted more by liner operators.Fuel consumption flexibility

A key feature of the electronically-controlled common-railsystem is the complete flexibility allowed in the timing,rate and pressure of fuel injection and in exhaust valveoperation. This is employed to advantage in the newlyintroduced feature of fuel consumption flexibility.

At the first stage of development of RT-flex engines, themain objective has been to achieve the same performancestandards as are achieved in the mechanical-camshaftengines, particularly with respect to power, speed, fuelconsumption, exhaust emissions, cylinder pressures, etc.

Thus the curve of brake specific fuel consumption (BSFC)of the first RT-flex engines has been the same as withcorresponding RTA engines, or perhaps slightly lower inthe part-load region. As the fuel injection pressure at part-

Type Cylinder No. No. Engines

RT-flex96C 12 1410 3

8 10

7 4RT-flex96C 31

RT-flex84T-D 7 3RT-flex84T-D 3

RT-flex60C 9 37 12

RT-flex60C 15

RT-flex58T-B 7 86 25 2

RT-flex58T-B 12

Total 61

Table 1: Numbers of Sulzer RT-flex engines delivered or onorder at the end of December 2003.

Fig. 11: Sulzer low-speedmarine engine programmewith the RT-flex engineshighlighted. The six SulzerRT-flex engine types covera power range of 5650 to80,080 kW(7700108,920 bhp).[03#017]

RTA48T-B

RTA52U-B

RTA84C

RTA72U-B

RT-flex68T-BRTA68T-B

RTA62U-B

RT-flex60C

RT-flex58T-BRTA58T-B

RT-flex50RTA50

RT-flex96CRTA96C

RT-flex84T-DRTA84T-D

102127

110137

82102

7999

7594

92115

91114

84105

99124

92102

6176

Speedrpm

5 15 20 30 40 60 80MW 10

Sulzer RT-flex

load is kept higher with the common-rail injection system,combustion is sufficiently better to have a beneficial effecton fuel consumption.

The new step is to introduce flexibility into thechoice of fuel consumption curve. Two fuel consumptioncurves are available as standard for RT-flex engines, thenew alternative given by Delta Tuning being a lowercurve with reduced BSFC below 90 per cent load (Fig.12). In both cases, the RT-flex engines comply with theNO

Xregulation of Annex VI of the MARPOL 73/78

convention, often referred to as the IMO NOX regulation.Sulzer RTA engines have always been highly

competitive in fuel consumption right across the loadrange owing to the use of variable injection timing (VIT).


7/9


Fig. 12: The new, alternativeBSFC curve for RT-flex engines

given by Delta Tuning comparedwith the original BSFC curves of

Sulzer RTA and RT-flex engines.All curves shown are for enginescomplying with the IMO NOxregulation.[03#117]

This has been particularly true for the RTA84T engineswhich since their introduction in 1991 have also had theadvantage of variable exhaust valve closing (VEC) whichfurther reduces the part-load BSFC. These benefits havealready been carried over to the electronically-controlled

common-rail systems of the RT-flex engines.The question, of course, arises as to why the BSFC

could not be lowered at all engine loads/speeds. It istechnically possible to do so. With RT-flex engines all therelevant parameters can be continuously varied so that theengine can follow any specified BSFC curve as engine loadand speed are varied. The key limitation today, however, isin the need to comply with the IMO NO

Xregulation.

Owing to the natural laws of physics and combustionchemistry, there is always a trade off between lower fuelconsumption and greater NO

Xemissions. At the present

state of technology, if the BSFC curve for an engineis lowered then there is an increase in NO

X

emissions.However, the IMO NO

Xlimit is specified as a weighted

average of NOX

emissions measured at certain engineloads and speeds. Thus it is possible to accept increases inNO

Xemissions in some ranges of engine load if there is a

compensating reduction in NOX

emissions at other engineloads.

This explains the shape of the new BSFC curve givenby Delta Tuning. The BSFC is lowered in the mid- andlow-load range, thereby increasing the NO

Xemission

levels at those load points, but then has to be increasedat high engine loads (90100% load) for a compensatingreduction in NO

Xlevels. The overall result is that an

Fig. 14: [02#123]

Usual operation:

all nozzles

in unison

Selective cut-out of injection valves

Smokeless operation at low speed

Two nozzles

Single nozzle

Time

Fig. 13: Sulzer RT-flex engines have the unique ability to cutoff individual fuel injectors, here shown schematically. This

feature is used to assure clean combustion for smokeless, stablerunning at very low speeds.[03#118]

RT-flex engine with Delta Tuning also complies with theIMO NO

Xregulation.

The fuel saving is attractive but it would not benefitall ship types to the same magnitude. It is of greateradvantage to those ships which spend a high proportion of

their time sailing in ballast or at reduced speeds.

Very slow running

Another key advantage of Sulzer RT-flex engines is theirability to run stably at very low speeds, lower than engines

with mechanically-controlled injection. They can runwithout smoke at 10-12 per cent nominal speed.

This ability will be very useful during transits ofthe Suez Canal, or during long port approaches andriver passages. Very low, stable running speeds are alsoadvantageous for tankers during lightering operations or

when loading at offshore oil fields.Such slow running has been well confirmed in service

in the Gypsum Centennial. It is made possible by theprecise control of injection, together with the higherinjection pressures achieved at low speed, and the cuttingout of injectors at low speeds.

Cutting out injectors is enabled by the separate controlof individual fuel injection valves (Fig. 13). This feature isunique to the Sulzer RT-flex system. Usually the injectionvalves operate in unison but, as the engine speed isreduced one injection valve can be cut out and at a lowerspeed a second injection valve can be cut out. Thus atminimum speed, the engine runs on all cylinders but with

just one injection valve in each cylinder.

BSFC

Load25%

RTA engines

100%75%50%

RT-flex engines:

Basic tuning

Delta Tuning


8/9


Reducing the number of injection valves in servicemakes injection of the reduced fuel quantities moreefficient, especially as the injection pressure is kept up toa higher value than in a mechanically-injected engine atlow speeds. If the RT-flex engine then runs for a periodin single-injector operation, the electronic control systemswitches between the three injection valves in a cylinder sothat the thermal load is equalised around the combustionchamber.

This arrangement provides more stable operation withbetter distribution of engine load and thermal loads thanif very slow running was to be achieved by cutting out

whole cylinders.

Low exhaust emissions

A clearly visible benefit of RT-flex engines is theirsmokeless operation at all ship speeds. This was welldemonstrated in the Gypsum Centennial(Figs. 15 and 16).The superior combustion performance with the common-rail system is achieved by maintaining the fuel injectionpressure at the optimum level right across the engine speedrange. In addition, the selective shut-off of single injectorsand an optimised exhaust valve timing help to keep smokeemissions below the visible limit at very low speeds.

The flexibility of the RT-flex engines will also allow

Fig. 15:Smokeless operationon heavy fuel oil at allspeeds was confirmed bymeasurements on the firstSulzer 6RT-flex58T-Bengine, shown here incomparison with thosetypical for Sulzer RTAengines.[02#010]

Fig. 16:Smokeless operation in

practice theGypsum Centennial

[02#041]

considerably lower NOX

emissions. With common-railinjection, a wide variety of injection patterns can begenerated (Fig. 17). The injected quantity of fuel can bedivided, for pre-injection, triple injection, etc. The SulzerRT-flex engine, with its individual fuel valve control, alsohas the unique ability to individually vary the injectiontiming and sequence between the three fuel injectors ineach cylinder and thus to generate a tailor-made heatrelease.

In engine tests, this degree of flexibility has proveduseful to reach NO

Xemissions of 20% below the IMO

NOX

limit with a moderate BSFC increase of 2.3%.

High reliability and redundancy

Reliability is crucial for all ship propulsion engineswhatever the size or type of ship. Though it is especiallytrue for the engines of, for example, large oil tankers withtheir pollution potential, and large container ships withtheir high-value cargoes and tight sailing schedules.

Not only has reliability been an important requirementin the development of Sulzer RT-flex engines but theinherent redundancy of the common-rail concept alsocontributes to ship safety. This is an attribute uniqueamong fuel injection systems to the common-rail concept.

The multiple fuel and servo oil supply pumps have

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0 10 20 30 40 50 60 70 80 90 100

Engine Load [%]

Filter Smoke Number [FSN]

HF O

380 cSt

3% sulphur0.1% ash

Conventional low-speed engine

OFF Aux. BlowerON

6RT-flex58T-B with Common Rail

Smoke visibility limit


9/9


adequate redundancy for the engine to deliver full powerwith one fuel pump and one servo oil pump out of action,and a strictly proportional reduction in power shouldfurther pumps be out of action. High-pressure fuel andservo-oil delivery pipes, and the electronic systems are also

duplicated for redundancy which extends to the separatecontrol of individual fuel injection valves.

Future potential

The common-rail systems incorporated in Sulzer RT-flexengines give the best potential for the future developmentof low-speed marine engines. The reasons can besummarised as: Simplest solutions are given by common rail for fuel

injection and exhaust valves Free choice for all parameters for fuel injection and

exhaust valves

Precise volumetric fuel injection control Separate control of individual fuel injection valves

unique to RT-flex Separation of functions delivery is handled at the

supply unit and control is locally at each cylinder unique to RT-flex

No external pressure storage or damping is needed unique to RT-flex

Stable pressure level in common rail Separation of heated fuel oil from precision parts

ideal for heavy fuel oil In-house design, with standardisation for different bore

sizes Pumping power minimised through suction pressurecontrol and rail pressure regulation

Minimised pumping volume Redundancy for reliability and safety Built-in monitoring Quick and easy maintenance.

To put it simply, our experience with various fuelinjection and valve operating systems camshaft-operated,hydraulically-operated and common rail has confirmedthat electronic control alone is not sufficient. It needsto be combined with common rail for progress as, for

example, in Sulzer RT-flex engines.It is clear, however, that the direction for future

engine developments will need to match shipownersrequirements. Some of the possible avenues to be

investigated might be: Flexibility for further improving fuel consumption and

lowering exhaust emissions Extendibility, for example to include direct water

injection for reducing NOX

emissions

Making engines self-adapting, with built-in feedbackcontrol for longer times between overhauls, varying fuelquality, varying waste heat recovery demand, varyingambient conditions, complying with local emissionsregulations, etc.

Not all developments will be restricted to newbuildingsor require additional hardware. Sulzer RT-flex engineshave the benefit that new operational features can beadded by simply updating the system software.

Conclusion

From all the experience so far, Sulzer RT-flex engines areclearly a major step forward in the technology of largemarine diesel engines. The combination of common-railconcepts and fully-integrated electronic control is theonly solution giving the degree of flexibility, together withreliability and safety, required to meet the challenges infuture marine engine applications in terms of emissionscontrol, optimised fuel consumption, insensitivity to fuelquality, ease of use, operational flexibility, etc.

References1. Stefan Fankhauser and Klaus Heim, The Sulzer

RT-flex: Launching the era of common rail on low-speed engines, CIMAC 2001, Hamburg.

2. Stefan Fankhauser, Worlds first common-rail low-speed engine goes to sea, Wrtsil,Marine News,No.3-2001, pp1215.

3. Kaspar Aeberli and John McMillan, Common Railat Sea: The Sulzer RT-flex engine, The Motor ShipMarine Propulsion Conference 2002, Copenhagen.

4. Huber, Konrad and Beat Gttinger, First year ofservice successful for first Sulzer RT-flex, Wrtsil,

Marine News, No.1-2003, pp48.5. Kaspar Aeberli, Experience with Sulzer Common-

Rail Engines, The Motor Ship Marine PropulsionConference 2003, Hamburg.

Needle lift

Cylinder pressure Rail pressureInjection pressure

Pre-injection Triple injection Sequential injectionFig. 17: Some of the fuel injection patternspossible with common-rail injection: pre-

injection, triple injection and sequentialinjection. Note the sharp beginning and endof the needle lift in all three types of pattern.

Sequential injection is unique to RT-flex enginesas the individual fuel injection valves are

separately controlled.[03#123]

Sultzer Common Rail

Documents

Transcript of Sultzer Common Rail