Century of Turbocharging

TurboM a g a z i n e

Published by ABB Turbo Systems Ltd

C E N T E N A R Y I S S U E

A centuryof turbocharging

2 ❯ Turbocharging in Switzerland – A history

3 Pioneering era

8 Turbocharging’s triumphant march

16 The modern era begins

23 A century of progress

Reprinted from Turbo Magazine 2 /2005

❯ C O N T E N T S

A century of turbochargingThe year 2005 will go down as a special year in our company’s history. In addition to

being one of the most successful to date, it reminds us of an important event which,

exactly one hundred years ago, laid the basis for the success we enjoy today.1905 was

the year that a highly talented Swiss engineer by the name of Alfred Buechi filed the

patent that would come to be looked upon as the starting point for exhaust gas turbo -

charging.

Alfred Buechi soon approached BBC in the hope of turning his “highly supercharged

compound engine” into reality. Some initial reservations on the part of our company

eventually, and thankfully, gave way to an agreement on collaboration. It marked the

beginning of one of the most notable success stories in Switzerland’s industrial history.

The past 100 years have brought changes to every area of life. Today, turbocharged

engines play a highly influential role in many of these areas, and our fascination with

them is in no way diminished. Also unchanged are the qualities – know-how, talent

and staying power – that are essential to achieve the goals we see as being achievable,

for our customers and for ourselves.

I hope you enjoy reading this short history of turbocharging and of our turbochargers. I

am sure that while some of the journey may be familiar, you will, like me, also find that

the story has much which is new to discover.

Daniel Arnet

President

ABB Turbo Systems Ltd

1

F O R E W O R D ❮

❯ C E N T E N A R Y

2

Turbocharging in Switzerland – A history

This issue of Turbo Magazine traces the history of the ABB turbocharger,

from its roots in the 1905 Buechi patent through the development and progress

of the VTR and RR series to the advanced TPS and TPL generations.

The high-tech ABB turbochargerwe know today is a far cry from

the first “supercharged scavengingblower with attached exhaust gasturbine” that Brown Boveri built for

an experimental two-stroke enginein 1924. But that ground-breakingmachine was also advanced for itstime. And it, too, was the product ofearlier invention and innovation,

inspired by an idea patented by aSwiss engineer 100 years ago andnow universally recognized as thestarting point for exhaust gas turbo -charging.

Baden – home of theABB turbocharger.

C E N T E N A R Y ❮

3

PIONEERING ERA

Diesel sets the scene

The story of the exhaust gas turbo -charger began in a period of phenomenal technical progress. Theearly years of the twentieth centurywere remarkable for the break-throughs they produced (not theleast of them powered flight!). Engi-neers and entrepreneurs alike wereactive in the promising field of thermal machines. Rudolf Diesel hadpatented the engine named after himalready in 1892, and its efficiencywas by now better than 30 percent.(Diesel even mentioned supercharg-ing in an early patent claim, but laterexperiments did not produce thehigh efficiency he was seeking, so hedecided to take it no further.)

The first diesel engines of MAN (MaschinenfabrikAugsburg-Nürnberg) inGermany and B&W(Burmeister & Wain) inDenmark, as well as ofother companies, datefrom this period. Swissmachine manufacturerSulzer also began to builddiesel engines at its factoryin Winterthur around1900. And in Baden, less than 50 kilometers away, a certain electri-cal engineering company by thename of Brown, Boveri & Cie wascelebrating its first decade in busi-ness by embarking on an excitingnew venture. It was the constructionof continental Europe’s first steamturbine, the very branch of engineer-ing that would later bring forth theBBC exhaust gas turbocharger.

Buechi’s 1905 patent

The Swiss engineer we have to thankfor the 1905 patent is Alfred Buechi,who at the time was working withSulzer. In it, he describes a “highly

supercharged compound engine”with a four-stroke diesel engine,multi-stage axial compressor andmulti-stage axial turbine mounted ona common shaft. In a subsequent USpatent Buechi went further, describ-ing the series arrangement of thethree machines in general terms in asub-claim.

Further work by Buechi at Sulzereventually led to publication in 1909of his idea for a freewheeling turbo -charger (it would nevertheless besome time before anyone would fol-low this up) and later, in 1915, to hisimportant “scavenging patent”.

It was also in 1915 that Buechi, look-ing for a partner, first contactedBrown Boveri in Baden. The company, which by then had alreadygained a great deal of experience

in designing andbuilding turboma-chinery, consideredBuechi’s proposal,but turned downthe opportunity ofcollaboration, as itdid again later in1919, on the groundsthat “the project as a whole is undesir-able and uneco-nomical”. Whatever

the reasons for this conclusion, advo-cates of turbocharging did exist atBBC and it would not be long beforethey were making a strong case forits development.

Parallel developments

Around the same time, work onsupercharging aircraft engines wasgoing on in France under AugusteRateau and at General Electric in theUSA under Sanford Moss.

In a 1916 patent (which was not pub-lished until 1921) Rateau, who hadcollaborated with Brown Boveri ingas turbine development in the early

1900s, described devices for regu -lating a supercharging compressor driven by an exhaust gas turbine,and in 1917 manufactured and testedsuch a device. Aircraft with turbo -charged engines were in use towardsthe end of and after World War I, butdevelopment was not taken any further. Alfred Buechi and others later acknowledged that Rateaushould take the credit for havingmanufactured the first turbocharger.

Moss was the first to manufacture turbochargers on a regular basis.Interestingly, the early GE Moss turbo charger had a manually con-trolled flap which, in certain flightconditions, made it possible to blowoff the exhaust gases and bypass the gas turbine – something wenowadays refer to as a waste gate.

First BBC steam turbine – the branchof engineering that would later bring forth the BBCexhaust gas turbo -charger.

The compoundengine patented byBuechi in 1905 andrecognized as the starting point for exhaust gas turbocharging.

Alfred Buechi

Pho

to: B

aden

Tou

rist O

ffice


4

Turbocharging’s potential is

recognized

The change in Brown Boveri’s policycame in 1923 with the publication inGermany of a report on low-pressuresupercharging trials carried out byMAN. These trials, on a 160-rpm,four-stroke engine, had shown thatwith a charge pressure of just 1.35bar the engine output increased by33% even after the power for theelectrically driven blower had beensubtracted. The use of exhaust gas todrive the compressor promised a fur-ther 6 – 8% increase in power as wellas lower fuel consumption. On topof this, the operating pressure, thecombustion temperatures and theheat load on the walls all remainedwithin acceptable limits.

Brown Boveri now decided to applythe know-how it had acquired build-ing turbines and compressors to thedevelopment of superchargers.

First ships with

turbocharged engines

1923 was also the year that theVulkan shipyard in Stettin received acontract to build two large passenger

ships, the Preussen and the Hanse -stadt Danzig, for the East PrussiaLine. Each ship was to be poweredby two 10-cylinder four-stroke MANengines, built under licence and turbocharged from 1,750 to 2,500horsepower. The engines had a com-mon exhaust gas receiver for allcylinders, which meant that theyoperated under constant pressure.The turbochargers, de signed andbuilt under Buechi’s supervision,were manufactured in the Vulkanworks in Hanover, with BBC inMannheim providing the compressorwheels. After being tested in May1926, they were installed in the shipsin September of the same year. Thesetwo ships were the first in maritimehistory to be powered by turbo -charged engines.

As important as this event was, how-ever, we have to go back three yearsto trace the first-ever industrialexhaust gas turbocharger.

World’s first heavy-duty

turbocharger

In 1923 Swiss Locomotive andMachine Works (SLM), like Sulzerbased in Winterthur, was also seri-

How turbocharging works

The output of an internal combus-tion engine is determined by theamount of air and fuel that can bepressed into its cylinders ➊ and bythe engine’s speed. Turbochargerssupply air to the engine at a highpressure, so more air is forced intothe cylinders and is available forcombustion.

An exhaust gas turbocharger isdriven, as its name suggests, by theengine’s exhaust gas ➋. This gas, at a temperature approaching600 °C, is directed at high velocityonto the blades of a turbine ➌,which drives a compressor wheel➍ mounted on the same shaft. As itrotates, the wheel (or “impeller”),sucks in ambient air through a filter-silencer, compresses it andfeeds it via an after-cooler ➎ to theengine’s air re ceiver ➏, from whereit passes to the cylinders.

Turbocharging increases engine out-put by up to four times. Thus, 75 percent of engine power isdependent upon the turbocharger.

➊

➋

➌

➍

➎

World’s first turbocharger for a large diesel engine. Delivered in 1924, it had external plain bearings and a two-stage compressor for a pressure ratio of 1.35.


5

ously considering the potential bene-fits of supercharging.

SLM had a two-stroke experimentalengine on the test rig that year whichneeded bringing up to a higher powerlevel with better fuel consumption.Brown Boveri recommended usingan exhaust gas turbocharger thatwould feed into the scavengingblowers, and SLM subsequentlyplaced an order for such a machine.In June 1924 turbocharger VT402 1,the world’s first heavy-duty exhaustgas turbocharger, left the Badenworks of Brown Boveri.

In the same year, discussions into the possibility of collaboration withBuechi began.

The “Buechi syndicate”

Things were now moving fast. Oneyear later, in 1925, Buechi took out apatent in his own name that was tomake him world-famous. Referred toas the “main patent”, it detailed theadvantages of pulse operation for

Buechi’s “main patent”

A so-called “pulse system” feedsthe exhaust gases of the enginethrough narrow pipes to the turbo -charger’s turbine, thus driving thecompressor. The pressure variationin the small-volume pipes allowsoverlapping of the inlet andexhaust, which permits the com-pression space in the engine cylin-ders to be scavenged with cleanair. Cylinders that do not disturbeach other’s scavenging processare connected to one exhaust pipeaccording to the engine’s firingorder. Buechi’s 1925 patent laid thefoundation for the future success ofturbocharging.

low-pressure supercharging (see panel), and was, within a short time,being used all over the world. The“main patent” was the breakthroughthat everyone had been waiting for.

A new company, known as the“Buechi Syndicate”, was set up thefollowing year for the purpose ofpromoting the further developmentof the “compound combustionengine with an exhaust gas turbineand a supercharger pump”. Underthe terms of the contract, Buechi wasin charge of engineering and cus-tomer relations, Brown Boveri wouldbuild the turbochargers, and SLMwas to provide the diesel engines forthe tests and trial runs.

Partnerships with engine

builders

An improved, larger turbochargerdesignated VT 592 was supplied toSLM in 1927 for a second experimen-tal engine. The results were impres-sive. Licensing agreements were nowbeing concluded between the syndi-cate and numerous leading enginemanufacturers. Other applicationsfor turbocharging were also underinvestigation. First test runs on diesel-

1 V stands for “Verdichter”, the German wordfor “compressor”; T is for “turbine”; 400 wasthe diameter of the compressor wheel in mm;2 says that the compressor has two stages.

VT 592 turbocharger for the second SLM experimental engine,supplied in 1927.


6

electric locomotives took place, whileturbochargers were also recommend-ing themselves for more economicoperation of stationary diesel powerplants.

From 1928 on, the trade magazine“The Motorship” was full of reportsof new vessels with turbochargedengines. Photos from that era typicallyshow the turbochargers standingalongside and connected to the four-stroke engines by long, dividedexhaust pipes. This, of course,allowed only weak pulse operation,but for the slow-running engines ofthe time it was sufficient.

Continuing development work wasalso providing new solutions. Morecompact installations were achievedafter 1930 with vertical-axis turbo -chargers mounted directly on theengine. Though still “horizontallydivided”, the turbochargers alsobecame simpler around this timewith the introduction of a single-stage compressor and improved, turbine blades. Brown Boveri wasnow working with major Germanengine builders, including DaimlerBenz, KHD (Kloeckner-Humboldt-Deutz) and MAN, and outstandingresults were being achieved.

Brown Boveri’s growing influencemanifested itself in a special way:The company was now advising cus-tomers on how to install the turbo -charger, the air and the gas pipes,and on the timing of the valves.Understanding the interaction be -tween the engine and the turbo -charger had become a key businessasset.

First standardized turbochargers

In 1932 an important design decisionwas made. Now that an optimal tech-nical solution had been found,Brown Boveri’s design engineerswent on to formulate specificationsfor a standardized range of turbo -chargers. This offered nine sizes, cor-responding to compressor diameters

MS Don Isidro, sailing in the late 1920s for de la Rama S.S. Co., Manila, under the power of its two turbocharged, 9-cylinder Krupp diesel engines, each with a shaft output of 3,500 horsepower.

View of the engine room of the MS Don Isidro. The VTx590 turbochargers are mounted on a platform behind the engines.

BBC turbocharger with single-stage compressor and overhung gas turbine wheel, dating from the year 1930.


7

VTy 410 vertical-axis turbocharger mounted ona Maybach 12-cylinder, four-stroke rail tractionengine.

ranging from 110 to 750 mm. Hori-zontal-axis units were denoted VTxand the vertical-axis machines VTy.Many of their features, such as (self-lubricated) external ball bearings,water cooling and the wide use ofstandard parts, were designed tomake service work easier, but thedecision to make the turbochargersmodular was key as it meant thatthey could be fitted to an enormousrange of engines.

The second half of the 1930s saw anupsurge in turbocharger sales. Thenumber of licence-holders was alsoincreasing, and the railcar businessboomed (in 1938 the VTy 410, a vertical-axis model for railcars,accounted for nearly one third of allsales). A growing number of orderswere also being received from the US market, one early customer beingthe American Locomotive Company(ALCO).

The two-stroke

engine challenge

The leap in diesel engine efficiencythat had taken place in the 1920s wasmade possible by direct fuel injectionand turbocharging. In the meantime,

The ALCO 8-cylinder, 900 horsepower engine was typical of the enginesbeing supercharged by Brown Boveri in the late 1930s (in this case with aVTx 350).

largely thanks to turbocharging, thefour-stroke engines had strength-ened their position relative to thetwo-stroke machines. But two-strokeengine development had not stoodstill, either. MAN and Sulzer, forexample, obtained interesting resultswith experimental two-stroke enginesin the early 1930s. How ever, neitherof these engines could really competewith the four-stroke machines.

Developments in

two-stroke turbocharging

Brown Boveri had already signalledits interest in two-stroke turbocharg-ing in 1925 with its purchase of the“Curtis” patent. This covered the so-called series arrangement, in whichthe turbocharger feeds air into themechanical scavenging air blower ofthe two-stroke engine, thus guaran-teeing start and operation at low load.As the engine output increases, theblower load is automatically reduced.

An internal study by Brown Boveri in 1934 also dealt with the super-charging of a 5,000 horsepower Sulzer two-stroke engine. It showedthat by using a turbocharger withaftercooler and pulse operation,under full load the turbochargeralone could be expected to supplyenough air. Partial-load solutions,such as auxiliary blowers and sup-plementary drives, were also men-tioned in the study.

Later, in 1940, tests were carried outwith a prototype VTx750 with radial-flow wheel on a 7,500 horsepowertwo-stroke Sulzer engine. The results,however, were disappointing, andfurther tests were halted.

Thus, until after World War II, turbo -charging with exhaust-driven turbo -chargers was confined exclusively tofour-stroke engines. The two-strokeengine, with its low exhaust-gas temperatures and dependence on ablower for the gas exchange, pre-

This locomotive of Swiss Federal Railways was still in service in the1990s, more than 50 years after being shown at the 1939 Swiss National Exhibition. Its four-stroke Sulzer diesel engine, which was fitted with a VTx 350 turbocharger, could deliver 1,200 horsepower at 750 rev/min.

sented significant difficulties due tothe low turbine and compressor effi-ciency at the time. Not until com-pressors and turbines with higherefficiencies were developed did turbocharging two-stroke marineengines become a practical proposi-tion. Thereafter, the use of exhaustgas turbocharging increased rapidly,helping the two-stroke engine toachieve absolute supremacy as adirect drive, slow-running marineengine.


8

VTF 201 BBC aircraftturbocharger with a

weight of only 32 kg.

Six-ton lorry with 100 horsepower

turbo charged dieselengine converted towood gas generator

(on right, behinddoor). The inlet for theVTx 110 turbo charger

can be seen abovethe left mudguard.

TURBOCHARGING’S

TRIUMPHANT MARCH

The VTR. .0 is launched

From 1940 on Brown Boveri had anew range of turbochargers underdevelopment. Denoted VTR, thesehad an open radial-flow compressor(hence the R) and light rotor, flexibly mounted external roller bear-ings and a self-lubricating system.Component standardization allowedlarge-scale production, and thereforecompetitive pricing. The introductionof the VTR..0 series after World War IIwas a significant milestone in theBBC turbo charger story. With a com-pressor efficiency of 75% for a pres-sure ratio of 2, it was only the start ofwhat was to come, but the BBCVTR..0 turbocharger marked thebeginning of a new era.

It was now possible to turbochargetwo-stroke engines with engine-driven scavenging air pumps. How-ever, to eliminate the scavengingpumps and reduce fuel consumptiona pulse-type turbocharging systemwas needed, and it would be severalyears before this feature would besuccessfully introduced (in 1951) ona B&W marine propulsion engine.

The Buechi syndicate had mean-while been dissolved. Brown Boverihad built up its own turbochargerdesign department and also had itsown test center and production facil-ities. The decisive move had beenmade from individual to industrialturbocharger manufacturing. Firstsigns of a global turbocharger servicenetwork were also visible.

The post-war boom …

There was intense demand for turbo -chargers in the post-war years, andone development in particular wasdriving it – the growing status of oil

as the preferred energy carrier. Overthe next decade or so the world’smerchant fleet doubled in size, withtanker capacity growing even faster.For more and more of these vessels,the power source of choice was thediesel engine.

… and final breakthrough

The period between 1945 and 1960saw the final breakthrough for turbo -charging, first for four-stroke enginesand then, from 1951 onwards, alsofor two-stroke engines. Boost pres-sures increased slowly but steadilyduring this period, although sales

1,000

1930 1940 1950 [year]

2,000

3,000

4,000

Demand for BBC turbochargers was strong inthe post-war years. Numbers supplied each year(excluding units manufactured under licence).

Brief excursions into new areas

In the years leading up to and duringWorld War II, Brown Boveri, whichhad been looking for new markets,was also working on aircraft turbo -chargers. This involved some inter-esting issues, including, of course,the problems caused by the reduc-tion in air pressure as altitude in -creases. However, despite some further work in the post-war years in the hope of a profitable leisureflying market, it was no more than a brief episode in the company’s his-tory. Large aircraft engines would, ofcourse, anyway soon be ousted bythe jet engine.

In 1940 the company also turned itsattention to the specialized area ofwood gas turbocharging! Liquidfuels were in short supply during thewar and converting diesel engines towood gas engines was seen as aviable way to provide motive powerfor road vehicles. However, the con-verted engines were weak, to say the least, and turbocharging was putforward as a solution. This venture,too, was short-lived. Once the warwas over and cheap liquid fuelsbecame available again, interest inwood gas units quickly, and under-standably, ended.


9

The progress of turbocharger technology from1924 to 1945. Designed for the same enginesize, the more compact VTR 320 on the leftachieves a much higher boost pressure than theearlier VT 402.

activities initially centered on low-pressure supercharging, i.e. pressureratios were about 1.5. The originalVTR turbochargers could be equip -ped with either a low-pressure or ahigh-pressure compressor, but thelatter was hampered by a restrictedvolumetric flow rate. Compressordevelopment in the following yearswould erase this disadvantage, push-ing the pressure ratio at full loadsteadily towards 3.

There were several important collab-orations with engine builders duringthis period. Some companies werealso experimenting with high boostpressures. MAN, for example, devel-oped around this time a high-pres-sure turbo charged four-stroke enginewith an effective efficiency of 45% –a figure that would not generally bereached for some time.

These collaborations showed onceagain the importance of the relation-ship between engine builder and turbocharger supplier. The new tech-nology had to be explained to theengine builders, who needed toknow how to make the best use ofthe exhaust energy in pulse opera-tion and, in many cases, even howthe exhaust pipes were to bedesigned.

There were several important collaborations with engine builders in thepost-war years. One was with English Electric, whose popular four-strokeV16 engine had four VTR 200 turbo chargers mounted on it.

Production in the new turbocharger plant, after 1949.

Ten-cylinder natural gas engine in the USA, turbocharged with twoVTR 400 units.

ABB’s “Shipowners’ Conferences” and the “ABBEvening” at CIMAC Congresses both stem from thistime. The importance of good customer relations hadbeen recognized very early on, and these events wereexcellent opportunities for ABB to explain to theshipping and engine-building community the latestadvances in turbocharger technology.

Strategic decisions

The post-war period saw severaldecisions taken that would set thepattern for the coming decades andwhich ultimately would play a keyrole in the worldwide market accept-ance of the BBC turbocharger.

In anticipation of Buechi’s mainpatent in the USA expiring in 1950,Brown Boveri was making a greateffort around this time to establishcontact with US engine-builders andgain market share. Competing withUS-built low-pressure turbochargers,however, was difficult and it becameclear that Brown Boveri would haveto concentrate on high-pressure turbo charging, where the technicalassistance it offered could tip the bal-ance in its favour. As part of its long-term strategy for the country, BrownBoveri also began to build up itsservice organization in the USA.

Being in the US market had anotheradvantage, too: The turbochargerorders for stationary gas engines pro-vided Brown Boveri with earlyknowledge and experience of thisimportant application.

In 1958 a decision was made to enterinto a collaboration that would be ofgreat strategic importance for BrownBoveri. This was the granting of a licence to Ishikawajima-HarimaHeavy Industries (IHI) in Japan tomanufacture BBC turbo chargers. IHI,which was then building enginesunder licence from Sulzer, went onto expand throughout Asia, and indoing so secured a dominant posi-tion for BBC turbochargers in thatregion. (This collaboration led to thejoint venture company Turbo SystemsUnited (TSU) being set up in 1998 byABB Turbo Systems and IHI.)


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Dorthe Maersk

Continuous refinement of turbo -charging technology had, by the early 1950s, set the stage for the nextpioneering act. In October 1952, the18,000 tonne tanker Dorthe Maerskwas launched. Built by the Danishshipyard A. P. Møller, it was the firstship to be powered by a turbo -charged two-stroke diesel engine(B&W, 6 cylinders). Two VTR630side-mounted turbo chargers raisedthe engine’s output from 5,530 to8,000 horsepower. Dorthe Maerskwas the first milestone in two-strokemarine turbocharging.

The focus shifts to Asia

The years between 1955 and 1975were a time of tremendous upheavalfor the shipbuilding industry. Duringthis period, half of the world’s ship-building moved to Japan’s yards,while western European shipyards’share went from 80% to less than40%.

There were other signs of change. By the mid-1950s it was not at allunusual for a Japanese firm manufac-turing under licence to be the first to put a newly developed modelfrom the licensing company on thetest bench. This was the case, forexample, in 1955/56 at MitsubishiHeavy Industries in Kobe, where

MHI had the first large turbochargedtwo-stroke Sulzer engine, a 7-cylinderRSA 76 (760 mm bore) running withtwo VTR630 units.

Shipbuilding booms

IHI wasn’t the only foreign companymanufacturing BBC turbochargers atthis time. In the period from 1955 to1975, Brown Boveri signed severalsignificant licence agreements – astrategy that would continue into thelate 1970s and 1980s with agree-ments between BBC and firms inChina, India and South Korea,among other countries. Shipbuilding

was at a record level, and the shipsbeing built were becoming biggerand faster. Crude oil prices were low;fuel costs had become insignificant;the diesel engine industry wasbooming.

The VTR..0 was in its heyday, withoverall turbocharger efficiency around56%. Engines with BBC turbo -chargers were continually breakingrecords for output and efficiency.

Two-stroke market developments

It is worth considering at this pointthe background to the next major

The 18,000 tonneDorthe Maersk was

the first ship to be powered by a turbocharged

two-stroke dieselengine.

Eriksberg B&W engine of type 10K98FF, rated 38,000 bhp, 27,950 kW, at 103 rev/min, fitted withfour VTR 750 units.


11

Two VTR 631 turbo -chargers on a Sulzer 7 RND 90two-stroke dieselengine under test in 1971.

Three VTR 630 turbochargers were installed on this Götaverken engine of type VGS 11U, rated at26,400 bhp, 19,000 kW, at 119 rev/min.

advance in two-stroke engine turbo -charging. The pulse system intro-duced in 1951 by B&W had theadvantage that a mechanical systemwas not needed at any point in theengine load range to guarantee theair supply. This was partly due to thevery high mechanical efficiency ofthe VTR turbochargers made possibleby their anti-friction bearings. Therequired exhaust gas energy wasobtained by opening the exhaustvalve early, although this also reducedthe effective expansion stroke.

An engine with scavenging pumps andwith constant pressure turbo chargingcan make do with a much later open-ing point for the exhaust valve, but ittakes some of the energy for the airsupply from the crankshaft. Thus, theengine drives its own scavengingpumps, with the result that fuel con-sumption is essentially the same as forthe B&W engine with pulse system.

The obvious way to improve fuelconsumption was therefore to useconstant pressure turbocharging andeliminate the scavenging pumps. Theproblem was, of course, that thiswould require turbochargers with a higher efficiency, and for themoment they were not available.

Enter the VTR. .1

New compressors with higher effi-ciencies and pressure ratios as well asincreased through flows were devel-oped through the 1950s and 1960s.Higher pressure ratios meant higherspeeds and increased axial thrust, forwhich improved bearing designs were necessary. Mountings were also rein-forced. In 1970, compressors with aneven higher throughflow were intro-duced and the gas outlet housing wasenlarged. The turbine intake was alsoreworked.

All of these improvements wereincorporated in 1971 in a new series

– the VTR..1. From now on, BrownBoveri could offer turbochargerswith an overall efficiency of almost60% for a wide range of applications.In the past, efficiency had risensteadily but slowly. This was the firstbig leap.

RR buttresses the lower end

of the range

In 1968, three years before the launchof the VTR..1, Brown Boveri broughta new series of small turbo chargersonto the market. Named RR due to itsradial turbine and radial compressor, it was developed for applications atand below the lower end of the VTR power range.

The introduction of the RR series ful-filled a market need that had beenevolving for some time. By the mid-1960s many firms were building turbochargers that competed for mar-ket share with the smallest VTR.Smaller, lighter turbochargers were in demand for the then modern, fast-running diesel engines in the lowerpower range. Designed with plainbearings for heavy duty, the RR150had a compressor pressure ratio ofup to 3.0 at full load. Brown Boverihad developed small turbo chargersduring and after World War II, but theRR150 was the first real small, seriesturbocharger to be built by the com-pany.


12

RR turbochargers

The RR turbochargers were intendedmainly for use with high-speed four-stroke engines. These engines pro-gressed enormously throughout the1970s, making further development

necessary. In 1981, Brown Boveriintroduced the RR153. This had fewer components than the RR150,was 20% lighter, and featured a 25%increase in airflow plus higher effi-ciency. The turbine had a profilednozzle ring, but was otherwise prac-tically unaltered. The RR153’s newcompressor wheel, with backsweptblades, represented a major step for-ward.

The introduction of the RR. .1 gener-ation in 1985 marked an other break-through. These turbo chargers were

completely new and set new stand -ards of efficiency for such smallunits, mainly as a result of theirinnovative mixed flow turbine. Inthe years that followed, the RR. .1

1.5 2.0 2.5

Compressor pressure ratio

Turb

ocha

rger

effi

cien

cy

3.0 3.5 �C [-]

�TC [%]

65

60

55

50

RR 151

RR 153

RR 150

The RR. .1 turbocharger

RR 153 turbocharger compressor wheel, with backswept blades.

Increase in RR turbocharger efficiency

Shipbuilding crises

The boom in the turbocharger busi-ness was still holding firm in the early1970s, thanks mainly to the strongperformance of the market for mainand auxiliary marine diesel engines.Then, in 1973, oil prices per barrelquadrupled and shipbuilding col-lapsed. Within a short space of time,whole fleets of ships were beingmothballed.

Economic forecasts in the mid-1970swere speculative, to say the least. Oilprices continued to rise and fluctua-tions in international exchange ratestook their toll. Nevertheless, by 1980world trade had begun to recoverand since fewer new vessels werebeing built each year most of thelaid-up vessels were being returnedto service. It was not to last. An eco-nomic downturn at the beginning ofthe 1980s reversed the trend. “Threeyears worth” of ships had to be laidup again.

Japan and several newly developedcountries like South Korea, Singa-pore and Taiwan not only managedto avoid the downturn, theireconomies actually boomed at thistime. Western Europe’s share of theshipbuilding industry was shrinkingagain just as the Asian shipbuilders’,particularly South Korea’s, wasincreasing. One consolation for theEuropean shipyards was that theywere building mainly high-value,specialized vessels with strongerengines.

contributed to the popularity of thehigh-speed engine in applicationsranging from emergency gensetsthrough marine propulsion to off-highway vehicles. Designed for an engine output range of about500 to 1,800 kW, the RR. .1 can also take much of the credit for the wide-spread useof turbo -chargers ongas enginesin Europe andin the USA.

Caterpillar 3500 16-cylinder

V-engine with two RR 151

turbo chargers.


13

This Silja Line ferry was typical of the specialized vessels being built by European shipyards after mid-1970. Its four Wärtsilä-Pielstick 12 PC and three Wärtsilä-Vasa 6R32 diesel engines were fitted with VTR 321 and VTR 251 turbochargers, respectively.

The effect on the two-stroke

market …

The oil crisis created an entirely newsituation in the two-stroke market.Suddenly, fuel costs made up 30%,and no longer just 10%, of a ship’stotal running costs. Overall propul-sion efficiency became as importantas engine efficiency, and highlysupercharged, slow-running two-stroke engines were seen as the solu-tion. The market, rejecting cross-scavenged engines, turned to uni-flow scavenging. Two-stroke engineefficiency increased dramatically.

… and in the four-stroke sector

There were parallel developments in the field of four-stroke medium-speed engines. Although these arenot so dependent on high turbo -charger efficiency, highly turbo -charged four-stroke engines stilloffered some decisive economic

advantages. One major breakthroughwas that they could now be built foruse with heavy fuel oil. The greaterimportance of technology in thisbusiness also meant that BrownBoveri continued to collaborateclosely with the four-stroke engine-builders.

The VTR/VTC. .4

By the mid-1970s the VTR..1 hadtaken the original VTR concept as faras it could go. A new turbochargerrange with completely re-designedcomponents was on the drawingboard. Freed from the constraintsimposed by the first VTR, the VTR..4ramped up efficiency by five percentand more, and increased the peakcompressor pressure ratio to over 4.Following prototype tests on a Sulzerfour-stroke engine, the VTR..4 wasintroduced to the trade press inNovember 1978 and launched on themarket the year after.

NTC power turbine

The NTC power turbine wasdeveloped in the 1980s to takeadvantage of the high efficiencyof the VTR..4 turbochargers. Surplus ex haust gas (about 10%)was diverted to the turbine,which was coupled through anintegral “power take-off” gear tothe engine crankshaft. Sulzeradopted the power turbine for itsRTA series of two-stroke engines; later SEMT was the first companyto use it on a four-stroke engine(SEMT-Pielstick 4PC4.2).

By 1996, the power turbine wasno longer being offered. Turbo -charger performance was mean-while being utilized more fullywithin the engines themselvesdue to the rise in mean effectiveand maximum cylinder pres-sures.


14

Sulzer 32,400 horsepower 9 RLA90 two-stroke diesel engine with three VTR 714turbo chargers, manufactured by IHI, Tokyo.

VTC. .4 turbochargers on four-stroke engines in a stationary power plant.

Introduction of the VTR..4 providedthe impetus for new developments in diesel engine construction. Byraising the overall efficiency of turbochargers used with two-strokeengines from 60 – 62% to 65 – 68%, it contributed to the spectacular risein thermal full-load efficiency oflarge engines at this time from 38 – 40% to peak values of 44 – 46%.

In 1980 a compact version featuringmany of the VTR..4 turbocharger’scomponents (however with internalplain bearings) came onto the mar-ket. Denoted VTC..4, it paved theway for Brown Boveri’s collaborationwith Caterpillar in the USA and alsohelped the company become a sup-plier to British Rail at the end of the1980s.

In 1984 the efficiency of the VTR..4was raised again. The VTR..4A man-aged peaks of 70 percent, largelythanks to improvements to theinducer wheel made possible by“three-dimensional” manufacturing.

Uncooled VTR. .4 turbochargers

The original VTR..4 had beendesigned with a traditional water-cooled gas housing. All the old problems with gas housing corrosion

Section through an uncooledVTR. .4 turbocharger.

had meanwhile been solved, partlydue to the rise in two-stroke engineoutput, which had pushed up theexhaust gas temperatures. When theoil crisis hit in the mid-1970s, how-ever, ships reduced their speed, sothat engine outputs and exhaust gastemperatures fell sharply. Housingcorrosion became a potential prob-lem again, especially as poorer, high-

VTC. .4 turbochargers

VTC..4 turbochargers were suc-cessfully introduced to the mar-ket in the 1980s, with theVTC254, launched in 1985,quickly becoming the standardchoice for Caterpillar’s then new3600 diesel and gas engines.

The VTC..4 was also in demandin the Indian railway market inthe second half of the 1980s,when the VTC304 was success-fully tested on an ALCO 16-cylin-der 251 engine. More recently,Dalian Locomotive & RollingStock Works (DLRW) of Chinaordered VTC254 turbochargersin 2003 for its DF11G high-speeddiesel locomotives.


15

Compressor pressure ratio

Turb

ocha

rger

effi

cien

cy

� tot [%]

70

65

60

1.5 2.0 2.5

VTR . .1VTR . .4VTR . .4DVTR . .4E

3.0 3.5 �c [-]

Rise in peak efficiency of BBC turbochargers.

sulphur fuels were also being used.The reduced turbine outlet tempera-ture was also a cause for concern.The market began once again toshow an interest in “uncooled” turbochargers.

Brown Boveri initiated a develop-ment project that neatly solved theproblem of separating the external,supporting gas housing (which hadto remain cool) from the hot gaschannels. This solution, which wasalso suitable for the applicationsplanned for four-stroke engines(with higher exhaust gas tempera-tures), was retained in later versionsof the VTR, such as the VTR..4E.

One of the first series-produced VTR 304P turbo chargers was fitted to atype BR6 engine from Ulstein Bergen.

The VTR. .4E/4P/4D

Further development of the VTR..4turbocharger continued well into the1990s, producing peak efficienciesclose to 75% with the VTR..4E,launched in 1989, and pressure ratiosof more than 4 with the VTR..4P,that went onto the market in 1991.

In each case, the compressor playeda key role in the improved perform-ance. Five-axis milling now made itpossible to machine large compres-sor wheels in one piece and also to optimize their three-dimensionalshape. The stresses in the compres-sor wheel of the VTR..4P were

reduced so much that pressure ratiosof up to 4.7 could be obtained withan aluminium alloy impeller. Thanksto the high boost pressures achievedwith this turbocharger (4.5 at fullload and 5 at overload), four-stroke,medium-speed engines could utilizetheir potential for higher mean effec-tive pressures with a single-stage turbo charging system.

It was becoming clear in the early1990s that development of the present turbocharger generation wasreaching its limits, and that it wouldnot always be possible to fulfil themarket requirements with the current

High-efficiency VTR. .4E turbo charger, with external bearings.

Change of name

In 1988 ASEA and BBC merged toform ABB. In accordance with thenew company’s policy of decen- tralization, ABB Turbo Systems Ltdwas set up in the following year tohandle the turbocharger business.The worldwide reputation of theBBC turbo charger passed to theABB turbo charger.

This reputation was soon to beenhanced with a completely newrange of turbochargers. Advancedengines were under development

that required more sophisticatedturbochargers capable of higherpressure ratios and flow rates aswell as increased efficiency. At thesame time, end-users were raisingtheir expectations of high relia -bility, with longer times be tweenoverhauls, easier maintenance andan ex tended lifetime.

range. To meet demand forhigher turbo chargerperformance, espe-cially by MAN B&W,

ABB decided to com-bine the high-efficiency tur-bine of the

VTR..4E withthe VTR..4P compres-sor in a new type called the VTR..4D.No new development

work was necessary,enabling three sizes of the

VTR..4D to be launched on the market in 1994 and 1995.


16

THE MODERN ERA

BEGINS

The TPS/TPL generation leap

In the early 1990s ABB began todevelop a new generation of morecompact, lighter high-performanceturbochargers as successors to theVTR, VTC and RR. Two new families,the TPS for engine ratings from 500 to 3,000 kW, and the TPL forengine applications with outputsfrom 2,500 kW up to the highest inthe business, were designed from theground up.

Extensive market studies in the mid-1980s had shown that new, bench-mark turbochargers would be neededin all the main areas of business. Themarkets were also changing. Theengine-building industry was consol-idating. Fewer, but stronger andmore innovative companies weredeveloping new generations ofdiesel and gas engines. For theseengines, new standards of turbo -charger performance and reliabilitywere essential.

TPS turbochargers

Since the launch of the first RR turbo -chargers in 1968, the high- and medium-speed diesel and gas enginemarket had been changing fast. ABB

therefore set about developing theTPS – an entirely new generation ofsmall heavy-duty turbochargers thatwould cater to the foreseeable needsof future engines in the ranges cur-rently covered by the small VTR,VTC and RR turbochargers.

New compressors

and a new turbine

Fast-changing market conditions andcompressor design potential dictateda fast pace for development workaround the mid-1990s. It was con-cluded that the demands of theadvanced engines being built at thetime would best be met by two dif-ferent compressors. The decisionwas therefore taken to introduce theTPS turbo charger with the new D-compressor for pressure ratios up to4.2 at maximum continuous rating,and the equally new E-compressorfor pressure ratios up to 4.5. Thesecompressors have splitter bladedimpellers for high airflow rates andbackswept blades at the exit for awide compressor map. Peak com-pressor efficiencies of more than84% can be achieved.

For the TPS range, ABB developed a new mixed flow turbine and nozzle ring with different areas pertrim for part-load and full-load opti-mization. The turbine concept is suitable for constant pressure as wellas pulse turbocharging. A specially

TPS. . -E compressor and turbine.

TPS 48 qualification test on a Wärtsilä 4L20B engine.

coated version of the nozzle ring isavailable for applications in whichlow-quality fuel is used. The TPS alsohas a new oil-cooled bearing casing,enabling it to be used for applica-tions with turbine inlet temperaturesof up to 680 °C at constant load.

Testing and prototype trials of thefour TPS sizes – TPS48, 52, 57 and 61– took place on various customers’engines. Testing of the larger TPS 61D, for example, included trial runs in 1997 on an LH41LAdiesel engine from Hanshin rated at3,500 horsepower and 235 rev/min.Hanshin had designed this six-cylinder, four-stroke engine forinstallation on feeder ships in the Japanese merchant marine,where it would mostly run on heavyfuel.


17

TPS. . -F turbocharger

Engine emissions

and Miller timing

Diesel engine development in thefirst years of the new millenniumhas focused on higher brake meaneffective pressures and lower fuelconsumption. Engine builders andend-users alike are, however, alsohaving to consider the ramifica-tions of new emissions regulationsthat are on the way. To complywith the tougher legislation, turbo -chargers offering even higher com-pressor pressure ratios will beneeded.

An issue that is inseparable fromthe industry’s efforts to reduceengine emissions is “Miller timing”,i. e. early or late closing of the inletvalve. Providing the engine outputand boost pressure are constant,the cylinder filling is then reducedand the pressure and temperaturein the cylinders remain lowerthroughout the process. This is oneof the few measures that can beapplied in an internal combustionengine to simultaneously reduceNOx emissions and fuel consump-tion. A considerably higher boostpressure is, however, needed toreduce the temperature in theengine’s cylinders during the Millerprocess.

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

0.5 1.0 1.5 2.0 2.5 3.0

Com

pres

sor

pres

sure

rat

io

Volume flow

Engine operating line without recirculation

Engine operating line with recirculation

0.80

�C [-]

V298 [m3/s]

TPS. . -F33 compressor wheel with bleed slot in the wall insert for flow recirculation.

The TPS. . -F raises the

pressure ratio benchmark

The continuing trend in enginedevelopment towards higher specificpower is being accompanied byan urgent need to reduceemissions, and this hasled to most modernengines having someversion of the Millercycle incorporated in it(see panel). For theseand future advancedengines, ABB has devel-oped three new series coveringthe engine power range of 500 to3,300 kW. The first, denoted TPS. . -F33, was introduced to the market in2000/2001, followed two years later by TPS. . -F32, and in 2004 byTPS. . -F31. Based on the TPS. . -D/Eplatform, they achieve full-load pres-sure ratios of up to 4.75, 5.0 and 5.2,respectively, with an aluminium-alloy compressor wheel.

The new compressors developed forthe TPS. . -F series allow a 15% in -crease in the flow rates that can becovered by a given impeller size.This was achieved by adopting thesame approach to the compressor’sdesign as for the TPL. Instead of con-ventional “trimming”, whereby theblade size is adjusted to obtain the required flow rates, the volumeflow area for each turbo charger was

divided into three so-called designareas. Different, individual perform-ance targets were then formulatedfor these areas to ensure an optimalcompressor design within the physi-cal limits of each one.

The TPS. . -F was also the first ABBturbocharger to feature recirculationtechnology – a bleed slot around thecompressor wheel which, by improv-ing the flow field, increases the surgemargin. The effect of this slot is toenlarge the map width without com-promising the compressor’s high effi-ciency.

Improved compres -sor map achievedwith flow recirculation.


18

TPS with variable

turbine geometry

Developments in the diesel and gasengine markets also led in the mid-1990s to a version of the TPS withvariable turbine geometry (VTG).

One reason was the increasing pop-ularity of single-pipe exhaust systemsfor diesel engines. When conventionalturbochargers are used with these,part-load operation tends to be diffi-cult, load response is poor and smokeand particle emissions can be high.

Gas engine performance had alsobeen progressing impressively due toincreased efficiency and bmep, highaltitude capability and controlled air-to-fuel ratios. However, it was notpossible to simply use conventionalturbochargers with these engines,either. Solutions ranged frominstalling a waste gate or throttlemechanism to special matching ofthe turbocharger, but each had itsdrawbacks. Demand for a turbo -charger that would solve the problemwas especially strong in the 1,000 kWto 3,000 kW market segment.

An “adjustable” turbocharger wasseen to be the ideal solution for bothtypes of engine. Apart from eliminat-ing the losses occurring with a wastegate, a turbocharger with VTG ismore flexible in applications withchanging operating or ambient con-ditions. Precise control of the air-to-

TPS 57-F33 turbo charger on a Wärtsilä W6L26 diesel engine.

Variable nozzle ring of a TPS 57 VTG

turbocharger.

fuel ratio, so-called “lambda regula-tion”, is achieved with an innovativenozzle ring that enables the effectiveturbine area to be varied without anysignificant drop in turbine efficiency.The clearances for the movable nozzle blades are reduced almost tozero by springs that push the bladesagainst the opposing casing wall.

A turbocharger with VTG was suc-cessfully tested on a three-cylinderexperimental gas engine at UlsteinBergen in Norway at the end of 1996,followed some months later by firstfield tests with a TPS57D-VTG on agas engine operating in a commercialpower plant. These field testsshowed a significant gain in engineefficiency, as a result of which 26TPS57-VTG units were delivered to two Spanish power plants with 18-cylinder Ulstein Bergen engines in1999.

The TPL debuts

The TPL concept was developed as a platform for large modern diesel and gas engines with outputs from2,500 kW upwards. For this family,ABB’s engineers designed a new axialturbine family with the blade lengthsand stagger angles needed to coverthe entire volume flow range. Thebearing assembly is also new. Its axialthrust bearing has a free-floating discwith profiles on both sides, rotatingat about half the rotor speed. Thethick oil films this produces provideextra-high resistance to wear. Thenon-rotating bearing bushes are centered in a squeeze oil damper. Asa result of this new technology thebearing lifetime has been doubled.

Two new, different centrifugal com-pressor stages were also developedto ensure the full range of pressureratios required by modern turbo -charged engines. The design of theTPL compressor wheel, like that ofthe TPS wheel, is aerodynamicallyoptimized, with a splitter bladed


19

Axial bearingFree floating disc

Squeeze oil damperBush bearing

TPL bearing assembly

impeller for high airflow rates as wellas backswept blades at the impellerexit for a wide compressor map.New F-generation compressor stageswere developed for the TPL thatallow the efficiency, maximum pres-sure ratio and specific swallowingcapacity to all be significantlyincreased, the latter by as much as15% for a pressure ratio of 4.5. A largerange of turbine inlet casings, includ-ing optional waste gate connections,was also developed to enable the TPLto be used with all turbocharging sys-tems currently in use.

First TPL prototypes

and field tests

A very extensive qualification pro-gram and performance measure-ments in the labs provided hard evidence of the TPL’s capabilities,but experience with the new seriesstill had to be gained in actual engineoperation. Between 1996 and 1999,TPL turbochargers were subse -

quently installed on various engines,including the Wärtsilä 12V38 andCaterpillar MaK 16M32. A specialhighlight was the turbocharging ofthe then world’s most powerful four-stroke medium-speed engine,the Wärtsilä 6L64, with the firstTPL 80-A to be produced. Experi-mental runs on established enginesalso took place during this period, asdid field tests in four- and two-strokemarine applications on board differ-ent vessels.

In addition to these engine tests, field tests with the TPL were startedtowards the end of 1996. On the ferryMS Polonia the original VTR354 on the Wärtsilä 6L38 engine wasreplaced by a TPL69 to gain long-term experience and provide a statis-tical base for component lifetimepredictions. Further field tests, forexample with two TPL73 units in afour-stroke marine application andwith the larger frame sizes in severaltwo-stroke applications, took placethroughout 1997 and 1998.

The TPL. . -A is launched

The first of the new-generation TPLturbochargers to be introduced to themarket was the TPL. . -A. This serieswas developed for modern medium-to-large four-stroke diesel and gasengines and became a runaway success soon after its market launchin 1996. Applications range frommain and auxiliary engines for smalland large vessels, respectively, to

TPL 80 turbocharger


20

stationary diesel and gas powerplants.

Two compressor designs are avail-able. One offers a pressure ratio of4.2 with high specific flow capacitiesand high efficiencies; the other is for applications requiring pressureratios up to 4.5. Peak turbochargerefficiencies of 68% and higher canbe achieved.

Buquebus Line’s fastferry Catalonia,

with eight TPL 65-Aturbo chargers on its

four Caterpillar 3618 engines, broke

the record for the quickest surface

transatlantic crossingin 1998.

The larger TPL. . -A turbines have lacing wire through their blading todamp the vibration produced by thepulse turbocharging systems of manyof the four-stroke engines in usetoday. For the smaller sizes, ABB de veloped a single-piece, integralturbine.

In 1999, the TPL. . -A played a keyrole in, among other projects, the

development of ALSTOM EnginesMirrlees Blackstone’s 18-cylinderMB430M engine, at the time one of the largest four-stroke dieselengines ever built in the UK. The twoTPL77-A30 units for the engine werealso the largest frame sizes to be utilized up until that time. ABB alsoprovided Mirrlees Blackstone withengineering support in the form ofpredictive engine performance simu-lation results for this application.

Five frame sizes of the TPL. . -A are in series production, covering therequirements of modern four-strokediesel and gas engines with outputsof 2,500 kW to 12,500 kW.

The TPL. . -B takes on

the two-stroke market

Launched in 1999, the TPL. . -B turbo -chargers were developed primarily for large, modern two-stroke marinediesel engines with outputs from 5,000 to 25,000 kW per turbocharger.Worldwide de mand for larger ocean-going vessels was strong and new,more powerful engines for them wereunder development.

Since the constant-pressure turbo -charging systems used by two-strokeengines produce only weak ex -haust pulses, inlet conditions for theTPL. . -B turbine are constant. Thereis therefore no need for dampingwire – a feature that contributes twoto three percentage points to thealready high turbine efficiency.Robustness is nevertheless ensuredby the turbine’s “wide chord” designwith fewer, but stronger blades.

To further increase the volume flowand allow optimized matching to the engine applications, ABB’s engi-neers enlarged the diameter of theTPL. . -B’s compressors. Thanks to thesplitter bladed impeller design andbackswept blades, peak efficienciesof more than 87% are obtainable.

Caterpillar MaK16M32 diesel engine

with two TPL 65-Dturbochargers.


21

Maintenance and service considera-tions were also high on the agendaduring development of the TPL. . -B.Special attention was paid, for

example, to the dismantling of thebearings, rotor, nozzle ring and tur-bine diffuser, all of which can beremoved from the compressor side. TPL. . -A turbine blading with lacing wire.

TPR – a new railroad turbocharger

A new railroad turbocharger, theTPR, was launched in 2002 to meetdemand for extra power androbustness as well as better envi-ronmental performance in tractionapplications. Based on the TPLdesign, it features an integral high-efficiency turbine without lacingwire, an improved single-entry gasinlet casing and unique foot fixa-tion. Release of this turbochargerwas preceded by 50,000 hours of

field tests, carried out by IndianRailways with ten TPR61 unitsbetween 2001 and 2002.

Considerable interest in the TPR61has also been shown by China’sDalian Locomotive & Rolling Stock Works (DLRW), after earlier successful testing by DLRW of theTPL61-A turbocharger on its 16-cylinder V240ZJE and 12-cylinderV280ZJ engines.

TPL. . -B turbochargers were mainly developed for powerful, modern two-stroke engines on large container ships.

Initially, four frame sizes were consid-ered to be enough to satisfy the needsof the market in the medium term.The decision to develop a fifth, evenmore powerful turbo charger (TPL91)took account of shipbuilders’ planstowards the end of the millennium tobuild post-Panamax container vessels.ABB’s engineers were challengedonce more: The turbocharger was tobe designed for use on engines withpower outputs in excess of 100,000brake horsepower and yet still be compact. This was achieved bydesigning a new, shorter rotor and anew constant-pressure turbine anddiffuser. Mounting of the engine wasalso made easier by integrating the oil tank and the venting pipe con-nection. In November 2004, threeTPL91-B units were installed on the

world’s most powerful electronicallycontrolled 12K98ME MAN B&Wengine at Hyundai Heavy Industriesin Korea for official testing under fullload (93,360 brake horsepower).

TPL. . -C – catering to future

four-stroke applications

While the TPL. . -A/B turbochargersmeet the requirements of mostengine applications, the four-strokemarket continues to push for moreoutput and lower emissions. ABB has made use of the TPL’s modularplatform to introduce new compo-nents and innovative technologies in a new series – the TPL. . -C – thatcaters especially to this future mar-ket. The factors driving the develop-

22


TPL 91-B turbocharger

Test run with aTPL 85-B on a MAN

B&W 6S70MCengine built under

licence by HHM(Hudong Heavy

Machinery Co.) ofChina.


23

TPL 76-C turbocharger

ment of this brand-new turbochargerwere therefore, besides economicand operational considerations, therules set by bodies such as the Inter-national Maritime Organization (IMO)and World Bank calling for a reduc-tion in NOx and particulate emis-sions. Optimization of the combus-tion process and the turbochargingsystem is crucial to this end.

The characteristics of the TPL. . -Cturbocharger are aligned with the de -mands of future four-stroke, medium-speed diesel and gas engines in thepower range of 3,000 to 10,000 kWper turbocharger. As a result of amarket analysis that was carried out,the turbine of the two smaller sizes(TPL67-C and TPL71-C) is designedfor quasi-constant pressure as well aspulse-charging systems, and that ofthe larger TPL76-C for quasi-constantpressure systems. The former turbinetherefore has a damping wire, whilethe latter features ABB’s wide chorddesign. The two compressor stagesavailable for TPL. . -C turbo chargersare of the same basic design as thosefor the TPS. . -F series, but take fullaccount of the different TPL bound-ary conditions.

The TPL. . -C compressors also featurethe same recirculation technology asthe TPS. . -F compressors. By avoid-ing strong secondary flows and sepa-rations, this also helps to reducecompressor noise, especially at partload. Optional compressor cooling is another special feature of theTPL. . -C. This extends the field ofapplication for aluminium alloywheels, offering an economic alter-native to titanium impellers whenhigher pressure ratios are required.

The TPL. . -C booked an early successwith Caterpillar’s decision in 2004 to install the TPL71-C on the new Cversion of its German-built MaK M43six-cylinder, long-stroke, medium-speed engine. Caterpillar has alsowritten TPL. . -C turbochargers intothe specification for the seven-,eight- and nine-cylinder models.

A CENTURY

OF PROGRESS

Looking back

In the 100 years since Buechi’sfamous first patent, the exhaust gasturbocharger has become indispen-sable to the diesel and gas engineindustry. Investment in research anddevelopment over the decades hasbrought quantum leaps in technologyand design. Engineers from differentdisciplines have brought their inno-vatory genius to bear on the prob-lems that arose, and found solutionsthat have taken turbocharging steadilyforward.

ABB Turbo Systems, through BrownBoveri, was fortunate to have beenpart of the Buechi Syndicate. Earlycontact with engine builders all overthe world enabled our company toprovide engineering support that hasbeen to the general benefit of theindustry. And the learning curve hasbeen mutual: Often, it was the fieldexperience reported by customersthat spurred our development engi-neers to redesign and improve keycomponents and processes. Never-theless, the main driving force hasalways been the market. Nothingdocuments this better than theprogress demanded, and achieved,in turbocharger performance overthe years. Could Alfred Buechi everhave imagined efficiencies of 70%and more, or compressor pressureratios in excess of 5.2?

Looking ahead

A proud past is worth nothing if itdoes not stimulate to do better. Itwas the commitment to doing betterthat made first the VTR..0, then theVTR..1, the VTR..4 and the RR sucha success. And it is what has madethe new TPS and TPL generationstheir worthy successors. Ever since


24

�C [-]

5.5

5.0

4.5

4.0

3.5

Com

pres

sor

pres

sure

rat

io

3.0

2.5

2.0

1.5

1.00 2.00 3.00 4.00 5.00

Volume flow

6.00 7.00 V298 [m3/s]

2003 2004

2003

1996

1992

19781989

1970

1960

1996(2005)

Progress in the compressor perform-

ance of ABB turbochargers since1960 (full load, with

an aluminium compressor).

Note: The main source of information for thefirst two sections of this article, “Pioneeringera” and “Turbocharging’s triumphantmarch”, was “The BBC Turbocharger – ASwiss Success Story” by Ernst Jenny.Sources for the other sections include TurboMagazine 1990 – 2005, BBC/ABB Reviewand scientific papers published by CIMAC,ASME and ISME, among others. The authorwould especially like to thank Esko Laustela, Hansruedi Born and Peter Spengler forreviewing the manuscript.

ABB Turbo Systems’ headquarters in Baden.

Pho

to: M

BS

that very first VT402 left our Badenfactory in 1924, BBC/ABB turbo -chargers have continued to definethe state of the art.

The steady improvement in turbo -charger and engine efficiency overthe years has always relied on closecooperation between ABB and theleading engine-builders. It is thiscooperation that sets the develop-ment goals and which will, in allprobability, become closer as thedemands made on the “turbocharg-ing system”, and not just the turbo -charger as a component, increase.Adjustable turbocharger componentsor multi-stage turbocharging are twoof the possibilities here.

New products for a new era

ABB Turbo Systems is set on contin-uing the tradition of collaborationwith customers and on being the market leader. With products for tomorrow’s markets like theTPL65VA – the world’s first series turbocharger with axial turbine andvariable turbine geometry – or thenext generation of the successfulTPL. . -B series. Also under develop-ment is a larger TPL. . -C turbochargerand new turbochargers with very

high compressor ratios for futurehigh-speed gas engines.

The price of oil, at a level not seenfor years, is focusing attention onceagain on the turbocharger’s traditionalrole as a fuel saver. Market demandfor higher boost pressures and effi-ciencies, plus the need to reduce the environmental impact of marinetraffic, will require advanced turbo -chargers. With its state-of-the-artdevelopment, test and productionfacilities, ABB Turbo Systems is wellplaced to supply them. One hundredyears on, Alfred Buechi’s legacy is ingood hands.

Publisher:ABB Turbo Systems LtdHanspeter Zingg (HZ)

Editor:Malcolm Summers

Address:P.O. BoxCH-5401 Baden/SwitzerlandPhone: +41 58 585 77 77Fax: +41 58 585 51 44www.abb.com/turbocharginge-mail: [email protected]

Domino Style & Type AG: layout, typesetting and electronic publishing

Cover photo:Michael Reinhard, Herrliberg, Switzerland

Reprints are permitted subject to full acknowledgement.

© 2008 ABB Turbo Systems Ltd, Baden/SwitzerlandAll rights reserved

ABB Turbo Systems LtdBruggerstrasse 71aCH-5401 Baden / SwitzerlandPhone: +41 58 585 77 77Fax: +41 58 585 51 44www.abb.com/turbocharginge-mail: [email protected]

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Century of Turbocharging