Woodyard D. (ed.) Pounders Marine diesel engines and Gas Turbines
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in a dynamic fast vessel application exploiting an elastic mounting system—were
thus translated into the design parameters of the V28/33D engine. At the same
time the opportunity was taken to address other features in eliminating the pos-
sibility of problems in service: for example, minimizing overhangs and induced
stress in the engine, and reducing pipework on and off the engine.
Among the measures adopted to enhance performance, fuel economy, reli-
ability and serviceability were:
l Electronically controlled pump-pipe fuel injection system to foster low
specific fuel consumption and reduced NOx and particulates emissions
throughout the load range.
l Simple, single-stage high-efficiency turbocharging based on ABB Turbo
Systems’ TPL 65 turbocharger for improved specific fuel consumption
and lower operating temperatures; and a simple exhaust system with
rigid heat shields helps to minimize and ease maintenance.
l Integrated pipe design with four-pipe connection to reduce vibration and
ease installation and serviceability.
l Two-stage freshwater-cooled high-efficiency intercooler in the centre
of the engine to improve specific fuel consumption and curb NOx emis-
sions while reducing mechanical loading.
l Reduced number of components (around 50 per cent fewer than the
RK270 engine) for higher reliability and lower servicing costs. Multi-
functional integrated elements include a hollow camshaft doubling
as a main lube oil channel. External piping is minimized by the wide
use of existing drillings or cast-in passages for fluid transmission; and
pre-wired, modular and encapsulated wiring looms avoid the need for
exposed on-engine electrical cables.
l Rigid dry crankcase design for reduced weight and easier servicing.
l Low inertia/low friction two-piece pistons with alloy steel crowns to
reduce weight and improve specific fuel consumption; three-ring pack.
l Simplified gear train of robust construction; water and lube oil pumps
driven from the free end of the engine through gears housed in the pump
drive casing (Figure 22.33).
l External viscous damper for ease of maintenance.
V28/33D engine Details
Crankshaft: manufactured from a high-tensile NiCrMo continuous grain flow
steel forging.
Crankcase: machined from spheroidal graphite cast iron and featuring
underslung main bearings retained by two vertical studs and two cross-bolts
per side for overall stiffness. The main bearing caps are secured by hydrau-
lically tensioned studs to ensure maximum integrity of the crankcase system.
A 52° V-angle minimizes torsional effects and allows location of the intercooler
between the cylinder banks, reducing overhang loadings while minimizing
engine height. Inspection covers on both sides of the engine provide access
V28/33D engine 607
608 Man Diesel
to internal components, and selected covers carry the explosion relief valves.
Engine mounting on either anti-vibration mounting or solid seating is by sepa-
rate bolt-on feet.
Cylinder liners: individual units incorporating deep flanges, strategically
cooled by a separate water jacket enabling a dry crankcase to be used, reducing
overall weight. The running surfaces are plateau honed and finished to improve
oil retention throughout the liner life; a cutting ring is fitted at the top of the
liner to eliminate the build-up of carbon on the piston crowns and minimize
lube oil consumption.
Bearings: the generously dimensioned main bearings feature easily replace-
able thin wall, steel-backed aluminium–tin shells.
Camshafts: modular design with one cam element per cylinder; they are
hollow and form the main lube oil supply to the engine. Optimized cam pro-
files for electronically controlled fuel injection minimize Hertzian stresses,
enhancing reliability and extending component life. The camshaft drive is
located at the free end of the engine; the crankshaft gear drives via a compound
idler gear for each camshaft.
Piston: two-piece design with a lightweight body and alloy steel crown. A
three-ring pack comprises two chrome-ceramic compression rings and an oil con-
trol ring. The case-hardened gudgeon pin is fully floating and retained by a circlip
at each end. Lube oil is fed from the connecting rod through drillings in the gudg-
eon pin and piston to a cooling chamber in the piston crown. The oil is then dis-
charged through drillings in the underside of the piston crown back to the sump.
Connecting rods: made of forged high-tensile alloy steel; the rods have
obliquely split large ends that carry fully grooved bearings with the cap secured
by four hydraulically tensioned studs.
Cylinder heads: the individual heads have a thick combustion face incorporat-
ing coolant drillings. The two inlet and two exhaust valves, all with cooled seats,
surround the central fuel injector. Twin inlet ports connect directly to the air mani-
fold, and there is a single tandem exhaust port outlet in the top face for ease of
maintenance. The heads are held in place by four hydraulically tensioned studs.
Valve gear: each pair of valves, operated via pushrods and rockers, is
driven from the camshaft via bucket tappet-type followers mounted in a sepa-
rate housing bolted to the crankcase.
Air manifold: these are modular castings mounted down the vee of the
crankcase and incorporating passages for the lube oil and water systems.
Exhaust system: modular and compact, the system comprises single cylin-
der units bolted to the cylinder head and connected to the next unit with expan-
sion bellows. The whole exhaust system is arranged in a lagged enclosure
made up of two-cylinder units for ease of maintenance. The exhaust pipes are
top mounted and connected to their respective bellows by vee-band clamps;
and quick-release couplings are used on the rigid heat shield.
Charge cooler: the cylindrical two-stage charge cooler is contained in
a housing that includes part of the inlet ducting. The assembly is mounted
directly on top of the air manifold to provide good support. Special attention
was paid to minimizing overhangs on external brackets to reduce the impact of
shock loadings in fast commercial vessel or naval applications.
Turbochargers: twin high-efficiency axial turbine turbochargers are
mounted on a cast bracket at the free end of the engine.
Fuel system: an electronically controlled pump-pipe injector system is used,
with the fuel pump mounted in the cam follower housing which forms part of
the body of the pump. Low pressure, modular fuel supply and return rails con-
nect each pump to the next, and the short high-pressure pipes to the injectors
are double skinned. The electronic control for the fuel pump and injector is
mounted locally on the engine. The electronic system facilitates control of the
fuel quantity and injection timing independent of engine speed, enabling per-
formance to be optimized for the specific application.
Lubricating oil system: all contained on the engine. The lube oil pump is
mounted directly on the free end of the crankcase and driven from the cam-
shaft gear drive. The plate-type oil cooler is mounted horizontally on top of the
filter housing at the free end of the engine, the duplex filter incorporating an
integral oil thermostat.
Cooling system: a twin-circuit cooling system is used, with both pumps
mounted on the free end of the engine and driven by the camshaft gear, and
provision for a sea-water pump. The charge cooler thermostat is integrally
mounted in the turbocharger bracket.
Starting system: the air starting motor incorporates a control valve, pressure
regulator and strainer, and engages with a gear ring on the flywheel. A barring
motor can be supplied as a service tool or fitted as standard when it is fully
protected against inadvertent starting of the engine.
Governor: the engine is served by a digital engine management system
which controls its operation and communicates via a CAN bus link to a set of
intelligent cylinder control modules that drive the pump and injector solenoids.
The system dictates the fuelling, timing and pressure base upon pre-set mapped
information. The CAN bus link is also used to convey diagnostic information
back to the master controller for display and action. The cylinder control mod-
ules provide emergency governing in the event of a master controller or CAN
bus failure. Other similar redundant features are incorporated to promote maxi-
mum engine availability.
COMMOn raiL engineS
Like other major medium-speed engine designers, MAN Diesel has developed
a modular CR fuel injection system to foster free selection of injection tim-
ing and pressure independent of engine load and speed. The CR system was
first announced in 2004 in conjunction with the established 32/40 engine. Fuel
pressure generation and injection processes are separated and electronically
controlled. A prime advantage is the reduction of smoke emissions, especially
at low loads and during starting, and an improvement in the NOx-specific fuel
consumption trade-off.
Common rail engines 609
610 Man Diesel
Based on the segmented rail concept, MAN Diesel’s CR system is served
by high-pressure pumps which compress the fuel to the required pressure
and deliver it to in-line accumulator units forming the CR (Figures 22.35 and
22.36). Connections are provided on the accumulators for the injection valves
and for the fuel distribution and injection-control components. The CR injec-
tion system is fully compatible for use with heavy fuels having viscosities up
to 700 cSt at 50°C and temperatures up to 150°C, with all relevant components
designed to withstand these conditions; in addition, they meet stiff require-
ments with respect to resistance to wear by abrasive particles and the aggres-
sive contents of HFO. CR engines can be started and stopped on HFO, and in a
load range from 100 per cent down to 20 per cent they can be operated without
Figure 22.35 Key elements of Man Diesel’s Cr fuel injection system on a 32/44Cr
engine showing an accumulator served by a high-pressure pump and supplying two
injectors
Figure 22.36 arrangement of the Cr fuel injection system
interruption. Below 20 per cent load the engines can be run on HFO with a
time limit.
The CR injection system is modular in design and sub-divided into a series
of compact pressure reservoirs or accumulators; using multiple accumulators
reduces pressure fluctuations in the system and makes rational use of space
available on the engine. Each accumulator segment serves one or two fuel
injectors featuring conventional nozzles. The solenoid injection-control valves
are located on the segmented rails and connected to standard pressure-controlled
injectors. No separate servo circuit is required for activating the electronically
controlled injection valves which are arranged on the rail away from the hot
cylinder heads to secure greater system reliability and easier maintainability.
MAN Diesel reports that ease of installation and maintenance is also fostered
by the simple assembly procedures.
System safety and redundancy was a priority in development, leading to
the adoption of these key features:
l Injection pressure only during injection at the injection valve (no risk of
uncontrolled fuel injection because of leaking control or injection valves).
l All high-pressure lines, rails and units are double walled (no risk arising
from fuel escaping from leaking or damaged lines.
l Fuel-limiting valves on each cylinder (prevent uncontrolled injection).
l Non-return valves on each cylinder (ensure that fuel backflow from the
fuel low-pressure system into the cylinder is impossible).
l Use of at least three high-pressure pumps (emergency operation possible
in the event of failure of one pump).
l Safety valve with additional pressure control valve (emergency opera-
tion possible in the event of a fault in rail pressure control).
l Two rail pressure sensors and two engine speed/top dead centre pick-ups
(sustained operation if a sensor fault occurs).
Man 32/44Cr engine
MAN’s first all-electronic four-stroke engine, the 32/44CR design, was
launched in 2006 to supplement the popular 32/40 series with a CR fuel-
injected derivative. Retaining the 320 mm bore, the designers sought a higher
specific output (560 kW/cylinder), lower fuel consumption and reduced emis-
sions from a 10 per cent increase in piston stroke (from 400 mm to 440 mm).
The adoption of CR fuel injection and a considerably more efficient turbo-
charger also contributed to the power rise and emissions performance.
A higher power density than the 32/40 engine dictated a number of key com-
ponent modifications. In particular, the cylinder head and valves were modified
to cope with the increased cylinder pressure, and the valve guides were extended
and the seats modified. In addition, the crank drive was completely revised and
optimized using computer design techniques. An all-steel piston incorporating
two compression rings as part of an enhanced three-ring package features an
enlarged oil cooling gallery and larger piston pin diameter to match the higher
Common rail engines engines 611
612 Man Diesel
rating of the engine. The piston length was also reduced so that, despite these
measures, its weight was not higher than the 32/40 engine component.
Additionally, the cross-sectional diameter of the connecting rod shaft was
increased and the number of bolts at the big end bearing increased from two
to four. The higher number of bolts allowed for a more even distribution of
the stresses at the joint line and facilitated a slimmer connecting rod than with
the two-bolt design. Two camshafts are featured: a standard full-length unit for
actuating the gas exchange valves and a shortened unit serving the high-pres-
sure fuel injection pumps. Shortening the injection camshaft not only reduces
its friction characteristics but also the engine manufacturing costs: cited by
MAN Diesel as an example of how CR injection can improve not only engine
performance but also design and production.
Man 48/60Cr engine
CR fuel injection technology was extended by MAN Diesel to the 480 mm bore
48/60B design in 2007, the resulting 48/60CR engine retaining the 1200 kW/
cylinder rating of its predecessor (Figure 22.37). Following the precedent of
the 32/44CR engine, the solenoid injection-control valves are located on the
segmented rails and connected to standard pressure-controlled injectors. No
Figure 22.37 a 48/60Cr engine with a cylinder unit exposed for an exhibition
servo assistance of injector opening is required. Such an arrangement keeps
sensitive components away from the hot cylinder heads and facilitates retro-
fitting to engines in service since identical injectors are used on the 48/60B
design.
See separate chapters for other MAN Diesel group four-stroke engine designs
(Alpha, Holeby, Paxman, Ruston and SEMT Pielstick) as well as the 51/60 DF
dual-fuel engine (Chapter 2).
Common rail engines engines 613
MAN CR engine parameters
32/44CR 48/60CR
Bore (mm) 320 480
Stroke (mm) 440 600
Cylinders 6–10L/12–20V 6–9L/12–18V
Speed (rev/min) 720/750 500/514
Mean piston speed (m/s) 10.6/11 10/10.3
Mean eective pressure (bar) 26.4/25.3 26.5/25.8
Max. combustion pressure (bar) 230 –
Output/cylinder (kW) 560 1200
Power range (kW)
3360–11 200 7200–21 600
Specic fuel consumption (g/kW h) 177–179 174–180
615
C h a p t e r | t w e n t y t h r e e
Bergen (Rolls-Royce)
The diverse shipbuilding and marine engineering interests of Norway’s Ulstein
group for many years embraced the design and production of Bergen medium-
speed engines, now a key element of the UK Rolls-Royce group’s diesel inter-
ests. Two Bergen engine families for propulsion and genset applications—the
250 mm bore K-series which dates from the early 1970s, and the 320 mm bore
B-series introduced in 1986—have been progressively upgraded and were
joined in 2001 by a completely new design, the 250 mm bore C-series, devel-
oped in co-operation with Hyundai Heavy Industries of South Korea.
K-SeRieS
First introduced in 1971, the 250 mm bore/300 mm stroke K-engine was
designed mainly to be a genset drive but numerous propulsion plant applications
have been logged in tugs, offshore supply ships and fishing vessels. Engines
are available as in-line three-to-nine-cylinder or V12-, 16- and 18-cylinder
models covering an output range from 600 kW to 4010 kW at speeds of 720/750/
825/900 rev/min.
Design improvements introduced over the years have sought to maintain
market competitiveness, the maximum brake mean effective pressure being
raised from 20 bar to 22 bar to increase the output to 220 kW/cylinder. The later
adoption of a ‘hot box’ arrangement for the fuel injection system followed a
trend in larger engine designs. It provides the engine with cleaner lines and
improves the working environment in the machinery room: temperatures are
reduced and any fuel leakage from the injection system components is retained
within the box.
Other improvements have included a revised timing chain, sprockets
and camshaft system to extend service life and accommodate a higher injec-
tion pressure. The valve stem rotators have been strengthened and the valve
guides and guide seals improved to ensure better operational results running at
900 rev/min on heavy fuel.
The provision of a carbon-cutting (or anti-polishing) ring at the top of the
cylinder unit significantly reduced lube oil consumption and the amount of
616 Bergen (Rolls-Royce)
insoluble deposits in the oil (hence extending filter life). The ring comprises a
sleeve insert which sits between the top piston ring turning point and the top of
the cylinder liner. It has a slightly smaller diameter than the bore of the liner,
this reduction being accommodated by a reduced diameter piston top land. The
main effect of the ring is to prevent the build-up of carbon around the edges
of the piston crown which causes liner polishing and wear with an associated
increase in lube oil consumption.
A secondary function is a sudden compressive effect on the piston ring belt
as the piston and carbon-cutting ring momentarily interface; this forces lube oil
away from the combustion area and again helps to reduce consumption. The
efficiency of the rings was such that Bergen found it necessary to redesign the
ring pack to secure a desirable degree of oil consumption. The carbon-cutting
ring, refined over a 2-year period, is now standard on all new Bergen engines,
and numerous engines in service have benefited from retrofits.
B-SeRieS
The 320 mm bore/360 mm stroke B-series engine was conceived as a com-
pact, heavy fuel-burning main engine and launched in 1986 with special fea-
tures facilitating operation on lower price, poor quality fuel oils. The design’s
tolerance of fuel quality has been demonstrated by an offshore rig installation
running on crude oil direct from the well after degassing. A nominal rating
of 360 kW/cylinder at 750 rev/min was initially quoted but some of the first
engines sold were contracted at around 400 kW/cylinder, equivalent to a 10 per
cent overload.
An uprating in 1991/1992 took the output to 440 kW/cylinder at 750 rev/min
which yielded a power band of 1870 kW to 3970 kW from in-line six-, eight- and
nine-cylinder BR models. A decision to double the upper limit of the range—to
7940 kW—was announced in 1996 through the introduction of V12-, 16- and
18-cylinder models. These BV engines (see Section BV Engine) were planned
to benefit from Bergen’s exhaust emissions reduction R&D by adopting faster
fuel injection, a change in compression ratio and different valve timing to the
existing in-line cylinder engines.
The B-engine was reportedly the first of its size to feature a completely
bore-cooled cylinder unit and combustion space (initially, a bore-cooled
liner and head and, later, bore-cooled pistons). This arrangement yields good
strength and stiffness combined with good temperature control, which is
important in heavy fuel operation.
Early in the engine’s development it was discovered that the temperature
profile on the liner was not the optimum. The resulting design change, benefit-
ing subsequent production engines, has reportedly proved effective in the long
term for both propulsion and auxiliary power duties, even at medium load. A
drawback to the original bore-cooling concept soon became apparent, how-
ever: the use of electrically driven cooling water pumps. Electrical black-outs
could not be tolerated, and the fluctuation in cooling water flow away from the
optimum resulted in some cracking of liners. An early change therefore saw
a switch to engine-driven pumps and the incorporation of a new strengthened
liner design.
In Arctic areas, it was also found that piston rings were vulnerable to poor
ignition qualities and high temperature gradients, resulting, in some cases, in
ring cracking. This problem was solved by optimizing the clearances and the
layout of the ring pack.
Other refinements following early installations included an improved
bearing arrangement for the timing gears and, in line with other enginebuild-
ers, a new fuel injection system was introduced in 1991 to counter an indus-
try-wide problem of leakages. The complete injection system was enhanced
by bigger pumps, better seals, larger nozzles and improved high-pressure
pipes. The improvements coincided with the 1991/1992 decision to uprate the
engine’s output to 440 kW/cylinder while retaining the same engine speed of
750 rev/min.
Contributing to this power rise—and a brake mean effective pressure
increase to 24.4 bar—was the first application of ABB’s VTR-4P high-efficiency
turbocharger with a titanium compressor wheel, and a new type of composite
piston with a bore-cooled forged steel crown and nodular cast iron skirt. A carbon-
cutting ring (described above in the Section K-series) was introduced to the
B-engine in 1994.
The one-piece design cylinder block of nodular cast iron is arranged for an
underslung crankshaft and features large crankcase doors. A receiver and sup-
ply ducts for oil and water are cast in. The centrifugally cast cylinder liner is
bore cooled in the upper part only where cooling is needed; its running surface
is specially treated to enhance wear resistance. The bore-cooled cylinder head
is provided with a thick bottom for control of mechanical and thermal loads,
and six holding bolts for good load distribution. Heavy fuel service is under-
written by exhaust valves with a Nimonic head and welded-on hard seat facing.
A fully forged, continuous grain flow crankshaft has large diameter journals
and pins for low bearing loads, and is fitted with hydraulically tightened coun-
terweight bolts. The connecting rods are forged in alloy steel and machined
all over, and feature an obliquely split big end with hydraulically tightened
bolts. The tri-metal thin-walled bush bearings are formed from steel backed
with lead/bronze bearing material and soft overlay. The two-piece piston is fit-
ted with three compression rings and an oil scraper ring, all chromium plated
to secure low wear.
A L’Orange fuel injection system was developed for an injection pressure
of 1400 bar (endurance tested at 1700 bar) with constant pressure unloading for
cavitation-free operation at all loads and speeds. A Bergen-developed clean-
ing/lubricating system cleans the lower pump parts of heavy fuel residues and
lubricates the moving parts, helping to reduce the risk of fuel rack sticking
problems.
An impulse turbocharging system based on ABB VTR..4 turbochargers
is specified for six- and nine-cylinder engines, and a modified pulse converter
B-series 617