Woodyard D. (ed.) Pounders Marine diesel engines and Gas Turbines

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CAMshAFts

The cam shape was optimized and the camshaft material and hardening proce-

dure improved. The rollers were ‘ﬂexible shaped’ to avoid edge loading.

BeAriNgs

The application of ‘Rillenlager’ (Mibi’s multi-metal layer bearing) solved the

problem of damaged bearings due to catﬁnes in the fuel and extended bear-

ing lifetime to over 30 000 h. This means they can be re-installed at 12 000–

15 000 h service intervals and run for a similar second period.

turBoChArger

The MAN B&W turbocharger, introduced in the 1980s, was matched to the

28/32A engine and in conjunction with the compression ratio and valve timing

fostered optimized conditions for the valves. Inboard ﬂoating bearings, with

a reported lifetime of over 24 000 h, are lubricated by the engine lubrication

system.

turbocharger 535

537

C h a p t e r | n i n e t e e n

Caterpillar

The largest model in Caterpillar’s own-design portfolio—and the US-based

group’s only medium-speed engine outside the MaK programme—is the 3600

series. Since its introduction in the early 1980s, the 280 mm bore/300 mm

stroke design has earned numerous references in commercial and naval propul-

sion and auxiliary sectors as well as in power station, locomotive and industrial

applications. Higher-rated, lighter-weight versions were developed in the 1990s

and successfully applied to the propulsion of large fast ferries.

The 3600 series programme embraces six- and eight-cylinder in-line and 50°

V-conﬁguration 12-, 16- and 18-cylinder models. An output band from 1490 kW

to 4020 kW at rated speeds of 750–1000 rev/min was initially covered but the

upper limit from the V16-cylinder model was raised to 4320 kW and then to

5420 kW through improvements in combustion efﬁciency. Another 15 per cent

rise in speciﬁc output over the standard models in the mid-1990s addressed fast

ferry propulsion demands, taking the maximum continuous ratings of the V12

and V16 models to 4250 kW and 5650 kW, respectively. Power-related modiﬁ-

cations included a new high-pressure ratio turbocharger, a higher capacity after-

cooler, new pistons and cylinder liners, and a new bearing design.

Further reﬁnements for high performance duty, progressed in conjunction

with Bazan Motores of Spain, resulted in the 1998 launch of the V18-cylinder

3618 engine offering up to 7200 kW at 1050 rev/min. The same year brought

a rating rise for the 3616 engine, enabling it to be released with an output

of 6000 kW.

3600 SERIES

A standard speciﬁcation 3600 series engine (Figure 19.1) features the follow-

ing key components:

Cylinder block: A one-piece casting of heavily ribbed, weldable grey iron

alloy. The intake plenum runs the full engine length, providing even air distri-

bution to the cylinders.

Crankshaft: A press forging, induction hardened and regrindable. A coun-

terweight for each cylinder is welded to the crankshaft and then ultrasonically

538 Caterpillar

examined to assure weld integrity. The crankshaft end ﬂanges are identical to

enable full power to be taken from either end of the engine.

Bearings: The main, connecting rod and camshaft bearings are of steel-

backed aluminium with a lead–tin overlay copper-bonded to the aluminium.

Connecting rods: These are forged, heat treated and shot peened before

machining. The special four-bolt design allows for an extra-large bearing which

reduces bearing load, extends bearing life and improves crankshaft strength and

stiffness.

FIguRE 19.1 Caterpillar 3600 series medium-speed engine in in-line cylinder

conguration

Cylinder liners: High-alloy iron castings, induction hardened, plateau

honed and water jacketed over their full depth. The ﬂange cooling provided for

heavy fuel-burning versions reduces the top piston ring groove temperature.

Pistons: Two-piece components comprising a steel crown and forged

aluminium skirt for strength and durability with light weight. Two rings are

arranged in hardened grooves in the crown, and another two rings in the skirt.

The top compression ring is barrel faced and plasma coated for greater hard-

ness. The two middle rings are taper faced and chrome plated, while the lower

oil control ring is double rail chrome faced with a spring expander. Cooling oil

is jet sprayed into passageways within the piston.

Valves: These seat on replaceable induction-hardened inserts. Positive rota-

tors are provided to increase valve life by maintaining a uniform temperature

and wear pattern across the valve face and seat. The exhaust valves speciﬁed for

heavy fuel engines received special attention to extend their lifetime. Caterpillar

reports that Vanadium-induced corrosion is signiﬁcantly minimized by using a

Nimonic 80A material in the valves and reducing the exhaust valve temperature

to 400°C. A low temperature is maintained by exploiting valve overlap, water-

cooling the insert seats and applying a ceramic coating to the valves.

High-efﬁciency turbochargers (one set is mounted on the in-line cylinder

models and a pair on the vee-models): Equipped with radial ﬂow compressors

and axial ﬂow turbines. The axial ﬂow turbine combined with a Caterpillar-

supplied washing device is said to be well suited to heavy fuel operation. The

turbochargers are water-cooled and their bearings lubricated with engine oil.

The turbocharger technology combined with a large cylinder displacement and

efﬁcient aftercooling yields a high air/fuel ratio. The results are more complete

burning for maximum efﬁciency and better cooling of the combustion chamber

and valves.

Cooling system: A single external cooling system supplies water to the two

water pumps. The system sends cool water to the aftercooler and oil cooler,

and hot water to the jacket water system to combat fuel sulphur-induced corro-

sion. The option of separate circuit cooling is offered for heat recovery.

Lubricating system: This features a pre-lube pump and a priority valve

which regulates oil pressure at the oil manifold rather than at the pump.

Bearings are thus assured continuous lubrication if the ﬁlters plug. Duplex ﬁl-

ters with replaceable elements allow servicing without shutdown.

Fuel injection: Caterpillar’s unit injector system has reportedly proven itself

in distillate, marine diesel oil and heavy fuel-burning operation. Efﬁcient com-

bustion is promoted by a high injection pressure (1400 bar) and precise timing.

The mounting of the unit injector pumps directly in the cylinder head, however,

allows the external fuel lines to carry only 5 bar pressure, reducing the danger of

line breakage. Injector tip cooling—reducing carbon formation on injectors—is

available optionally for heavy fuel-burning engines. Individual control racks for

each cylinder foster precise injection timing and minimize fuel wastage.

Exhaust and air intake systems: These contribute to fuel efﬁciency and

response. The air induction system is routed from the turbocharger to the intake

3600 series 539

540 Caterpillar

plenum with only one right-angle bend to the aftercooler housing. The exhaust

manifold system is dry shielded to secure a low surface temperature.

The pumps, ﬁlters and coolers are engine mounted. An accessory module—

which can support an expansion tank, heat exchanger, instrument panel, heater

and other support elements—simpliﬁes installation. It can be front engine

mounted or remotely installed up to 8 m from the engine.

Ease of maintenance was addressed by arranging the gear train components

for removal or replacement without taking off the front or rear engine cover.

The crankshaft damper is mounted outside the engine housing for optimum

cooling and accessibility; bolted covers and replaceable nylon bearings permit

rebuilding of the damper on site. Four inspection covers for each cylinder allow

convenient inspection and service access to the connecting rod and main bear-

ings, the segmented camshaft (one per cylinder), the pushrods and fuel linkage,

the injector and valve train.

The 3600 engine family is released for operation on fuels with a viscos-

ity and contaminants up to CIMAC class K55 (700 cSt at 50°C) at speeds of

800 rev/min and below, and CIMAC class G35 (380 cSt) 800 rev/min. The fol-

lowing features distinguish the heavy fuel engine from its distillate fuel-burning

counterpart: water-cooled valve inserts; ceramic-coated exhaust valves; fuel

injector nozzle tips optimized for high viscosity fuel; cooled fuel injector nozzle

tips; higher mass ﬂow rate turbocharger components; remotely mounted heated

fuel ﬁlter; ﬂange-cooled cylinder liners; and a turbocharger water wash system.

Caterpillar 3600 Series Engine Data

Bore

280 mm

Stroke 300 mm

Displacement 18.5L/cylinder

Cylinders

6/8L, 12/16/18 V

Compression ratio 13:1

Rated speed

750–1000 rev/min

Mean piston speed 7.5–10 m/s

Mep, mcr 22–23.7 bar

Mep, csr 20–21.5 bar

Output range 1490–7200 kW

3618 (BRaVO) EngInE

A V18-cylinder derivative of the 3600 series was jointly developed by

Caterpillar with the Spanish enginebuilder Bazan Motores to target high-speed

ferry propulsion opportunities (Figures 19.2 and 19.3). The 3618 engine was

initially released in 1998 with a fast commercial vessel rating of 7200 kW at

3618 (bravo) engine 541

FIguRE 19.2 High performance version of Caterpillar 3600 series engine

FIguRE 19.3 One of four 7200 kW Caterpillar 3618 engines installed in a fast

catamaran ferry

542 Caterpillar

1050 rev/min; higher sprint ratings were available for military applications.

The designers sought improved engine reliability and maintenance-friendliness

in addition to a 17 per cent rise in speciﬁc output (to 400 kW/cylinder). An

improved power-to-weight ratio was also yielded despite increased component

robustness, primarily by using nodular cast iron for the block, adding strength

without increasing wall thickness and weight.

All critical operating temperatures—coolant, lube oil and exhaust gases—

are lower than previous 3600 series engines, despite the higher power output.

An 80°C reduction in the inlet temperature to the turbocharger was secured,

promising improved engine reliability and durability. A new sea water pump

provided 33 per cent more ﬂow and 60 per cent more suction lift. A signiﬁcant

contribution to higher performance came from an ABB TPL65E turbocharger,

with a compressor bypass system closely matching the amount of intake air

to the operating requirements and eliminating mid-speed instability. The new

aftercooler was twice as large as before.

Other new elements include: a simpliﬁed and improved rear engine gear

train (the idler gear removed to form a direct V-drive to the camshafts); new

stainless steel fabricated exhaust manifold sections with permanent lagging to

reduce maintenance as well as bulk; high strength Nimonic valves for both air

intake and exhaust gas ﬂows; a deep bowl steel piston crown connected to a

new nodular iron skirt for added strength; interior piston cooling and wrist pin

lubrication doubled with two oil jets per cylinder; and a new crankshaft coun-

terweighted to optimize rotary mass balance. Oblique split connecting rods

ease servicing: rods are pulled with the piston, allowing cylinder overhauls to

be executed without draining the engine.

Some of these features were applied to an uprated 3616 engine, released

in 1998 with an output of 6000 kW at 1020 rev/min (equivalent to 375 kW per

cylinder) for fast ferry propulsion. A 6 per cent power rise over the standard

V16 model’s 5650 kW was achieved without increasing peak cylinder pressure.

Smoother acceleration, higher efﬁciency, lower emissions and more ﬂexible

installation requirements were also gained. Optional fore and aft turbocharger

mounting was offered, along with off-engine lube oil coolers and a compres-

sor bypass air induction system. The bypass system promotes more efﬁcient

engine operation at full power without causing surging at part load, such as

during acceleration.

C280 EngInE

An updated manifestation of the 3600 series was launched in 2005 in the shape

of the C280 series, which beneﬁted from electronic fuel injection to optimize

economy and reduce emissions across the operating range. Six and 8-cylinder

in-line and V12- and V16-cylinder conﬁgurations cover a power range from

1730 kW to 5420 kW for propulsion plants and from 1900 kW to 5420 kW

for genset and diesel–electric applications (Figure 19.4). A running speed of

900 rev/min or 1000 rev/min can be chosen.

All design parameters and key components—notably the cylinder block,

crankshaft, connecting rod, piston and camshaft—remained unchanged from

the 3600 series but an important new feature, Electronic Unit Injection (EUI),

replaced the mechanical fuel injection system. Caterpillar’s EUI fuel system is

based on cam-actuated mechanical pump/nozzle units which have the potential

for modelling the course of fuel injection by electronic control. The system com-

bines Caterpillar’s ADEM III electronic control system with electronic injec-

tion units to secure high precision (Figure 19.5). Combustion can be optimized

C280 engine 543

FIguRE 19.4 a V12-cylinder version of the C280 engine

FIguRE 19.5 Electronically activated fuel injection nozzles serve C280 engines

544 Caterpillar

for each engine speed and power by variable injection timing and duration. By

optimizing the combustion process, the EUI system reduces fuel consumption in

part-load operation as well as visible smoke and emissions.

Described as maintenance free and requiring no fuel cooling, the ADEM

III system features watertight electrical connections and a CANJ1939 data

link; a back-up module can be conﬁgured to provide redundant control.

The electronic fuel system was already proven in Caterpillar’s 3500B

series high-speed engines. High-pressure fuel lines are not required, allowing

threaded connections and double-walled lines to be dispensed with in the low-

pressure fuel system. The injection pressure is generated by a pump integrated

in the injection units. Magnetic injection valves, replacing mechanical synchro-

nization of the injectors, effect the fuel supply. The ADEM III system controls

each injection valve in such a way that the injection timing and duration are

optimally set to match the speciﬁc power and engine speed requirements for

each speciﬁed torque.

In addition, the system monitors other engine parameters, such as the boost

pressure generated by the turbochargers, and handles power measurement,

programmable droop, controllable gain and adjustable fuel/air ratio. With these

features, which can be programmed by the operator, the fuel system can be tai-

lored to the individual application. Histograms of engine operation can also be

produced to provide evidence of performance over time.

A number of improvements incorporated in the C280 engine resulted from

service experience with the 3600 series in marine installations, among them:

l High performance aftercoolers, speciﬁed as standard, ensuring a lower

boost air temperature and extended valve lifetimes.

l An anti-polishing ring in the cylinder liner, preventing the collection of

sooty deposits above the piston crown, fostering optimum setting of lube

oil quantity and increasing the liner lifetime.

l Bimetal cylinder liners handling cyclic load changes and contributing to

an extended component lifetime.

Field tests and in-service experience have reportedly conﬁrmed the envi-

ronmental and fuel economy beneﬁts of the engine, along with low noise and

vibration.

See Chapter 30 for Caterpillar high-speed engines.

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C h a p t e r | t w e n t y

Deutz

A wide range of high- and medium-speed engine designs was produced over

the years by Deutz, which absorbed another German four-stroke enginebuilder,

MWM, and was latterly known as Deutz MWM. The medium-speed programme,

no longer produced, focused on the 240 mm bore 628 series. A 250 mm bore 632

series, co-developed with US-based General Electric Transportation Systems

and introduced from 1994, became available only as a gas engine covering out-

puts from 3000 kW to 4000 kW. Higher speciﬁc ratings were yielded by larger

engines in the earlier programme: the 330 mm bore 645 series (See Section TBD

645 Series) and the older 370 mm bore 640 series. Deutz is now associated more

with small high-speed engines for marine leisure markets but examples of the

following medium-speed designs remain in service.

628 SERIES

The 240 mm bore/280 mm stroke 628 design was produced in six-, eight- and

nine-cylinder in-line and V12- and V16-conﬁgurations covering a power range

from 995 kW to 3600 kW at 750–1000 rev/min.

A one-piece crankcase of nodular cast iron with suspended main bearings

transfers gas and mass forces directly to the crankshaft bearings. Two hori-

zontal and two vertical bolts for the bearing cap form the integration between

the main bearing and the crankcase. Cast-on mounting straps enable ﬂexible

engine mounting, and a high degree of crankcase stiffness is achieved through

deep main bearing caps tightened cross-wise.

The drop-forged steel crankshaft is dimensioned for mechanical security.

Inductively hardened journals and an oil supply to the main and connecting rod

bearings independent of piston cooling help to minimize bearing wear.

A composite piston incorporates a forged steel upper part and forged alu-

minium lower part. A side-mounted injection spray nozzle arranged in the

crankcase continuously supplies the piston with cooling oil, intensively cool-

ing its head, ﬁre land and ring section by the shaker effect.

A nodular cast iron cylinder head, hydraulically bolted to the crankcase at

four points, incorporates two inlet and two exhaust valves. The charge air pipe

is split between the cylinder heads and connected by sliding pieces. Ease of

maintenance was sought by the designers: it reportedly takes no more time to

disassemble the entire cylinder head than it takes to remove the valve cages.