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

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with thermostatic valves, continuously regulate cooling water temperature to

achieve the optimized operating condition. Because charge air from the turbo-

charger never falls below the dew point, there is no danger of water condensa-

tion in the cylinders.

The cooling water system comprises an LT system and an HT system, each

cooled by freshwater. The LT circuit is used to cool charge air and lubricat-

ing oil. The HT circuit cools the cylinder liners and heads, fostering optimized

combustion conditions, limiting thermal load under high load conditions, and

preventing hot corrosion in the combustion area. Under low load, the system is

designed to ensure that the temperature is high enough for efﬁcient combustion

and that cold corrosion is avoided.

Water in the LT system passes through the LT circulating pump which

drives the water through the second stage of the charge-air cooler and then

through the lubricating oil cooler before the water leaves the engine together

with the HT water. The amount of water passing through the second stage

of the charge-air cooler is controlled by a three-way valve dependent on the

charge-air pressure. If the engine is operating at low load condition the tem-

perature regulation valve cuts off the LT water ﬂow, thus securing preheating

of the combustion air by the HT water circuit in the ﬁrst stage.

The HT cooling water passes through the HT circulating pump and then

through the ﬁrst stage of the charge-air cooler before entering the cooling water

jacket and the cylinder head. It then leaves the engine with the LT water. Both

LT and HT water leave the engine via separate three-way thermostatic valves

that control the water temperature.

All moving parts of the engine are lubricated with oil circulating under

pressure, the system served by a lubricating oil pump of the helical gear type.

A pressure control valve built into the system reduces the pressure before the

ﬁlter with a signal taken after the ﬁlter to ensure constant oil pressure with

dirty ﬁlters. The pump draws oil from the sump in the base frame, the pres-

surized oil then passing through the lubricating oil cooler and the ﬁlter. The oil

pump, cooler and ﬁlter are all located in the front box. The system can also be

provided with a centrifugal ﬁlter. Lubricating oil cooling is carried out by the

LT cooling water system, with temperature regulation effected by a thermo-

static three-way valve on the oil side (see earlier). The engine is equipped as

standard with an electrically driven pre-lubricating pump.

The L16/24 engine is prepared for MAN Diesel’s CoCoS computerized sur-

veillance system, a Microsoft Windows–based program undertaking fully inte-

grated monitoring of engine operation, maintenance planning, and the control and

ordering of spares. The four CoCoS software modules cover engine diagnosis,

maintenance planning, spare parts catalogue, and stock and ordering.

Each cylinder assembly (head, piston, liner and connecting rod) can be

removed as a complete unit for repair, overhaul or replacement by a renovated

unit onboard or ashore. Replacing a cylinder unit (Figures 30.11, 30.12 and

30.13) is accomplished by removing the covers and HP fuel injection pipe, and

disconnecting a snap-on coupling to the exhaust gas pipe. The only cooling

man (Holeby) 781

782 High-Speed Engines

FigurE 30.11 man l16/24 engine: preparing for cylinder unit removal

Bushes for charge

air and cooling

water are pushed

to the right

Removal of

cylinder unit

O-ring

Cyl.

unit 1

Cyl. unit 2

Cyl. unit 3 Cyl. unit 4

Cooling

water

connections

FigurE 30.12 man l16/24 engine: preparing for cylinder unit removal

water connections are to the cylinder unit as there is no cooling water in the

base frame. Inlet and outlet cooling water passes between cylinder units via

bushes which are pushed aside in disassembling a unit. The charge-air connec-

tions are dismounted in the same way. The four hydraulically fastened cylinder

head nuts and the two connecting rod nuts (all six are of the same size) are then

removed, allowing the 200 kg unit to be withdrawn from the engine.

The design principles of the L16/24 engine were later applied to the larger

L27/38 and L21/31 medium-speed engines, respectively introduced in 1997

and 2000 for both genset and propulsion applications (see Chapter 22).

mitSuBiSHi

Fast ferry propulsion business potential stimulated the development in the

early 1990s of the Mitsubishi S16R-S high-speed engine by the Japanese

group’s Sagamihara Machinery Works. The higher-performance V16-cylinder

model was evolved from the established S16R design which had been in pro-

duction since 1989 as a general purpose marine engine. A constant pressure

turbocharging system based on a newly developed turbocharger and a revised

fuel injection system contributed to a 20 per cent rise in the power output.

The 170 mm bore/180 mm stroke design has a maximum continuous rating of

2100 kW at 2000 rev/min with overload ratings up to 2300 kW.

mitsubishi 783

FigurE 30.13 man l16/24 engine: removing a complete cylinder unit

784 High-Speed Engines

The weight was reduced to 89 per cent of the original engine, primarily

through the adoption of aluminium alloy components optimized in size for

the duty. An overall weight of 5500 kg underwrites a power-to-weight ratio of

2.62 kg/kW.

motorEn- unD turBinEn-union

A portfolio of high-performance high-speed designs with an upper output limit

of 9100 kW is offered by MTU (Motoren- und Turbinen-Union) of Germany,

which was created in 1969 when Daimler-Benz and MAN consolidated the

development and production of relevant engines from MAN and Maybach

Mercedes-Benz. MTU Friedrichshafen became part of the Deutsche Aerospace

group in 1989 and subsequently a DaimlerChrysler company before coming

under the umbrella of the Tognum Group in 2006.

Series 396

Addressing lower power demands, MTU’s Series 396 engine is long established as

a propulsion and genset drive, the 165 mm bore/185 mm stroke design delivering

up to 2560 kW at 2100 rev/min from V90° conﬁguration 8-, 12- and 16-cylinder

models (Figure 30.14). Engines are available in three different versions:

l TB04, with external charge-air cooling (intercooler in raw water circuit).

l TC04, with internal charge-air cooling (intercooler in engine coolant circuit).

l TE04, with internal charge-air cooling (intercooler in engine coolant

circuit; split-circuit coolant system).

TE split-circuit cooling system: the Series 396 engine—and other MTU

designs—can be supplied with the TE split-circuit coolant system with a

power-dependent sub-circuit to cool the combustion air. Optimum performance

FigurE 30.14 mtu 16v 396 tE94 engine with split-circuit cooling system

is fostered throughout the engine’s power range: at idling speed the air sup-

ply is heated to achieve complete fuel combustion; in the medium power and

full load range conditions are optimized for high output while keeping thermal

stress on engine components at a low level.

Coolant ﬂow from the engine is split in two. Approximately two-thirds

of the ﬂow pass through a HT circuit and returns directly to the engine inlet,

while the remainder is fed into a thermostatically controlled LT circuit. During

engine idling or low load operation the thermostat allows heated coolant to

bypass the recooler on its way to the intercooler in order to warm up the com-

bustion air and prevent white smoke in the exhaust.

An annular slide valve in the thermostat remains in its initial position until

increasing power raises the coolant temperature, causing the wax pellet in the

thermostat to expand. Gradual closing of the bypass line now directs the cool-

ant stream through the recooler. As a result, coolant entering the intercooler is

at a low temperature which, in turn, underwrites a high-combustion air volume

and, consequently, maximum engine power. After ﬂowing through the inter-

cooler and the oil heat exchanger, ‘cold’ coolant rejoins the uncooled HT cir-

cuit, thereby cooling the total volume ﬂow before it re-enters the engine.

Sequential turbocharging is exploited for propulsion engines required to

deliver high power in the lower- and medium-speed ranges. The system incor-

porates two or three turbochargers with automatic on/off control as a function

of engine speed, power demand and turbocharger maximum efﬁciency. In addi-

tion to increased torque the system yields reduced fuel consumption and lower

exhaust temperatures.

Cylinder cut-out (no fuel injection into selected cylinders) is adopted for

engines operating under varying speed conditions (low idling speed). The

system enhances combustion at idle, thus shortening the warm-up phase and

avoiding white smoke from unburnt fuel, and generally contributing signiﬁ-

cantly to environmental compatibility.

Series 595

A power range from 2000 kW to 4320 kW at 1500–1800 rev/min is covered by

the 190 mm bore/210 mm stroke Series 595 engine, introduced in 1990 in V12-

and V16-cylinder versions for propulsion and genset applications (Figure 30.15).

Contributing to a compact design yielding power-to-weight ratios of under

3 kg/kW and a power-to-space ratio of 250 kW/m

(including all ancillaries)

are the following features: a V72° cylinder conﬁguration with all ancillaries

arranged for space saving within the engine contour; nodular cast iron crank-

case extending below the crankshaft centreline to maximize rigidity; crankshaft

with hardened main and connecting rod bearing radii, designed to withstand

ﬁring pressures of up to 180 bar; individual fuel injection pumps designed for

injection pressures of up to 1500 bar; plate-type coolant heat exchanger inte-

grated with the engine; split-circuit coolant system; and two-stage sequential

turbocharging system with charge-air cooling for boost pressures of up to

4.8 bar. The turbocharging sequencing is electronically controlled.

motoren- und turbinen-union 785

786 High-Speed Engines

Components requiring regular servicing are located to provide good access

at the engine’s auxiliary power take-off end. Maintenance is also smoothed by

the modular arrangement of functionally interlinked components, plug-in con-

nections and the omission of complex pipework, hose couplings and cabling. A

new ECS was purpose-developed by MTU for the Series 595 engine to provide

information for the operator, promote easier operation and enhance safety, reli-

ability and economy. The safety functions embrace engine and plant monitor-

ing, overload protection, diagnostics, automatic start-up and load control.

Series 1163

The highest power outputs from the MTU programme were offered for many

years by the Series 1163 ‘frigate’ engine (Figure 30.16). The 230 mm bore/

280 mm stroke design is produced in V60° conﬁguration 12-, 16- and 20-cylinder

versions delivering up to 7400 kW at 1300 rev/min for commercial and naval

propulsion installations. The key elements of the design are summarized as

follows.

Crankcase: nodular cast iron structure with access ports on both sides and

a ﬂange-mounting facility for alternators or other driven machinery; a welded

sheet steel oil pan is provided.

Cylinder liner: replaceable, wet-type centrifugally cast.

FigurE 30.15 v16-cylinder mtu Series 595 engine

Cylinder head: cast iron component arranged with two inlet and two exhaust

valves, all equipped with Rotocap rotators, a centrally located fuel injector sepa-

rated from the rocker area, and a decompression valve.

Valve actuation: by two camshafts, roller tappets, pushrods and rocker

arms. Valve clearance adjustment is performed via two screws located in the

rocker arms.

Crankshaft: a single-structure forged component ﬁnished all over and fea-

turing bolted-on counterweights; axial crankshaft alignment is effected by a

deep-groove ball bearing.

Bearings: thin-walled, two-piece, replaceable steel-backed tri-metal sleeve

bearings for the crankshaft and connecting rod, with cross-bolted bearing caps.

Connecting rods: forged and ﬁnished all over and grouped in pairs to serve

two opposite cylinders.

Piston: composite-type with light alloy skirt and bolted-on steel crown,

cooled by oil spray nozzles; three compression rings are ﬁtted in the crown,

with one oil control ring between crown and skirt; all rings replaceable after

piston crown removal.

Fuel injection: direct injection by individual pumps and via short HP lines;

pump replacement requires no readjustment; gear-type fuel delivery pump; two

duplex fuel ﬁlters; cylinder cut-out facility available (see section Series 396

Engine).

Governor: hydraulic MTU unit mounted on the gearcase, with the linkage

between governor and fuel injection pumps accommodated in the gearcase and

camshaft space. Engine shutdown solenoids act on the fuel rack; in addition, inde-

pendent emergency air shut-off ﬂaps are arranged to block the engine’s air supply.

motoren- und turbinen-union 787

FigurE 30.16 mtu Series 1163 engine in v20-cylinder form

788 High-Speed Engines

Lubricating oil system: self-contained forced feed system, with oil ﬂow pro-

gressing through gear-type pumps, heat exchanger and ﬁlters to the engine lubri-

cation points. Oil for piston cooling is tapped off after the heat exchanger and

ﬁlters; the engine-mounted oil heat exchanger is integrated in the engine coolant

circuit (Series 1163-02 model) or raw water circuit (Series 1163-03 model).

Cooling system: two-circuit system; closed engine coolant circuit using two

centrifugal pumps; thermostatic control; recooling provided by raw water heat

exchanger or fan cooler.

Turbocharging: the Series 1163-02 model exploits pulse charging based on

two turbochargers (one turbocharger for the 12-cylinder engine) with intercool-

ers incorporated in the raw water circuit. The Series 1163-03 model exploits

constant pressure turbocharging with two-stage air compression and interstage

cooling; four or ﬁve charger groups (depending on the application) are under

sequential turbocharging control; the constant pressure exhaust manifold is

located in the V-bank, and charge-air pipework mounted externally; high- and

low-pressure intercoolers are incorporated in the raw water circuit. For start-

up and low load operation the Series 1163-03 model features a charge-air

preheater, fed with engine coolant, in each HP intercooler outlet. Coolant jack-

ets for the exhaust manifolds and turbocharger turbines of this model secure

reduced heat rejection.

Like the Series 595 engine, the Series 1163 design features inboard HP

fuel injection lines and the enclosure of all hot exhaust components in water-

cooled and gas-tight casings: valued for unmanned enginerooms by helping to

reduce the possibility of ﬁre in the event of fuel or lubricating oil leakages. A

triple-walled insulation design also maintains surface temperatures well within

the limit of 220°C dictated by classiﬁcation societies, as well as considerably

reducing radiant heat in the engineroom.

Sequential turbocharging (output-dependent control of the number of tur-

bochargers deployed) fosters high torque at low revolutions per minute (wide

performance band) and hence good acceleration. Optimization during sea tri-

als, with assistance from an ECS, can eliminate black smoke emissions.

An uprated Series 1163 engine for fast ferry propulsion beneﬁts from:

l An improved fuel injection system to optimize consumption and exhaust

emissions reduction.

l A higher cylinder head fatigue strength, thanks partly to bore cooling.

l Improved power and torque characteristics achieved by modifying the

two-stage sequential turbocharging system.

l Adaptation and optimization of the turbochargers to match the increased

cylinder output (325 kW).

l Intelligent electronic engine management.

Series 8000 Engine

MTU’s thrust in commercial and naval propulsion sectors was strengthened

in 2000 with the introduction of its most powerful engine ever designed, the

advanced 265 mm bore Series 8000 design (Figure 30.17). Innovative fuel

injection, turbocharging and electronic management systems proven on earlier

MTU engines are exploited, while a new modular power unit-based structure

helps to ease maintenance and minimize life-cycle costs.

The Series 8000 engine was conceived with the aim of consolidating the

company’s position in the market for fast ferries and extending opportunities to

mainstream commercial arenas, such as cruise liners. Outputs up to 9100 kW for

naval vessels and mega yachts were initially sanctioned from the V20-cylinder

model which launched the series, with an 8200 kW rating at 1150 rev/min ap-

proved for high-speed commercial tonnage. A potential for ﬁring pressures up

to 230 bar underwrites future power rises, projected after successful long-term

testing of engines in service. The ﬁrst four production 20V 8000 engines were

installed as a mega-yacht propulsion plant, subsequent orders calling for units

to power a large catamaran fast ferry, frigates and naval supply vessels.

A V48° cylinder conﬁguration contributes to a narrow engine (1.9 m wide),

well suited for fast catamaran and monohull ferries where machinery space

is at a premium. The speciﬁc power output related to volume and weight is

reﬂected in ﬁgures of 200 kW/m

and just over or under 5 kg/kW, depending on

the application.

Common rail fuel injection, proven on MTU’s 1996-launched 165 mm bore

Series 4000 engine, allows all injection parameters affecting combustion to be

independently controlled; these include such variables as the timing, period

and pattern of injection as well as the injection pressure. Independent control

fosters reduced fuel consumption and exhaust emission levels across the entire

motoren- und turbinen-union 789

FigurE 30.17 mtu Series 8000 engine in v20-cylinder form. note the fuel pumps

(lower right) for the common rail injection system

790 High-Speed Engines

engine power curve. The common rail system also beneﬁts engine noise and

vibration levels, substantially lowering them at idling and mid-range running

speeds compared with conventional systems.

Two HP fuel pumps mounted at the free end of the engine develop pressure

levels of up to 1800 bar. The fuel is pumped through double-walled delivery

lines arranged longitudinally down the engine and directed to the cylinders via

distributors into individual accumulators. The accumulators are large enough

to prevent any drop in pressure before the fuel injector when maximum fuel

quantities are being injected, and to prevent pressure oscillations in the system.

The fuel is injected via electronically controlled injectors arranged centrally in

the cylinder head.

Experience gained from numerous Series 4000 engines in service moulded

the common rail system created by L’Orange for the new larger engine, which

is detailed in Chapter 8. Considerable scope for further development of the

system promised further advances in fuel economy, emission levels and noise

reduction in future production engines.

The Series 8000 design’s sequential turbocharging system had been suc-

cessfully applied by MTU to its Series 396, 538, 595 and 1163 engines for

many years to secure a large performance map width. First ﬁtted on production

models in 1982, the system marries a series of individual turbochargers that can

be switched-in and -out while the engine is running to match the load. High-

brake mean effective pressures can thus be sustained even at low engine speeds.

Among the merits cited for the sequential turbocharging system are excellent

acceleration and substantially lower fuel consumption and smoke emission levels

at low- and medium-power rates. Additionally, in twin-engine plants with com-

mon transmission and ﬁxed pitch propellers or waterjets, the system can be run

on one engine virtually up to its rated power. Quadruple MTU ZR 265 turbo-

chargers are speciﬁed for the single-stage turbocharging system serving the

20V 8000 engine (Figure 30.18).

Both common rail fuel injection and sequential turbocharging systems con-

tribute to a claimed speciﬁc fuel consumption of below 195 g/kW h across a

broad power range, and less than 190 g/kW h at the most economical points.

These ﬁgures are achieved while maintaining NOx emissions within IMO lim-

its. Smoke indices are reportedly 0.4 Bosch throughout the entire engine per-

formance map and 0.2 Bosch at full load.

Electronics are increasingly exploited by engine designers, MTU address-

ing the full potential from the conceptual stage of the Series 8000. The result-

ing MDEC (MTU Diesel Engine Control) engine management system allows

all functions and parameters to be precisely monitored and controlled for opti-

mum effect. The system also incorporates the basic functions for trend analysis

and diagnostics, and the facility for integrating the engine in a comprehensive

control and monitoring package for the entire propulsion system as well as

other ship systems. MTU offers these advanced options in the shape of its RCS

(remote control system) and MCS (monitoring and control system) products.