Volvo 850 GLT Manual

Technical information
Engine
Volvo 850 GLT

Volvo 850 Engine
Introduction
The demands on the car of the 90's are
very high in every respect. As vehicle
manufacturer one can no longer con-
centrate only on a subset of all prop-
erties. To gain success, excellence is re-
quired in all areas.
Furthermore, the customer of the 90's
will not accept having to adapt himself
or herself to the vehicle. The vehicle
must instead be adapted to man. This
makes it necessary to study man-
machine interactions when developing
a new car.
These demands, coupled with the
many properties affected by engine
characteristics, create the need for a
property oriented development process
where the combination of all properties
are taken into consideration from the
very beginning.

Development goals
Every customer expects good comfort,
good performance and fuel economy
from their car. This in turn, places a
demand for effective and efficient
technical solutions; to choose, as Vol-
vo sees it, the best solution for each
specific purpose.
The challenge for Volvo con-
sequently meant to combine a roomy
interior with a solid safety structure,
compact exterior dimensions and ef-
fective energy absorption with a pow-
ertrain combining comfort, per-
formance and energy efficiency.
A transverse installation of an in-
line engine is today accepted as the
best technical and most space efficient
solution. This is a solution already
chosen for the Volvo 400-series and
was on space, packaging and handling
grounds also chosen for the Volvo 850
GLT.
The development of the new engine
is the second step of Volvo's new
modular engine family, the N-series.
The first step was the in-line six
B6304F, which was introduced in the
Volvo 960 in August 1990.
The modular engines have several
identical components. The major com-
ponents are machined in a common
transfer line, in a highly rational and
most cost-effective manufacturing
process.
The normal order of priority for en-
gine properties during design and de-
velopment within Volvo Car Corpora-
tion is the following:
- Exhaust emissions
- Fuel economy
- Driving pleasure
- Performance
The interactions between these
four main properties are very strong
and it is very difficult to alter one
without affecting the others.
Since a lot of emphasis during the
development of the Volvo 850 was
put on performance and driving
pleasure, this had its effect on the in-
ternal relationships of the four prop-
erties given priority. In order to meet
the performance requirements with
maintained fuel economy, a variable
induction system was introduced.
This made it possible to combine
high torque at low engine speeds with
high power at high engine speeds,
keeping fuel consumption optimized.
Big efforts have also been made to
reduce noise and vibrations. There-
fore the best ignition timing has not
only been determined by emissions,
fuel consumption, performance and
driveability but also by its effect on
noise and vibrations. Comfort is a
property that also has been given
high priority when developing the en-
gine for the Volvo 850.
Another example of this is throb-
bing and sawing powertrain motions
that goes with a transverse engine in-
stallation and front wheel drive. Such
motions have been minimized by
electronic dashpot functions and oth-
er features of the engine management
systems.

The Volvo 850 engine concept
The engine in the Volvo 850 GLT is
an in-line 2.5 litre five-cylinder called
the B5254F. Thanks to an extremely
compact design of the engine and
transmission (See Technical in-
formation Transmission) it has been
possible to install it transversely (fig-
ure 1), still allowing for excellent han-
dling properties and an extremely
small turning circle (10.2 metres) for a
front wheel drive car of this size. The
Volvo 850 GLT is the first passenger
car that has an in-line five-cylinder en-
gine installed transversely driving the
front wheels. Overall length of the
complete powertrain, engine and trans-
mission, is only 948 mm.
The main characteristics of the
B5254F are:
- Five cylinders with four valves per
cylinder and a high compression ratio
- High performance and good fuel
economy without negative influence
on driveability
- Minimized engine vibrations thanks
to inherent engine and transmission ri-
gidity, damped engine and suspension
system and a separate insulated sub-
frame carrying the powertrain.
- A variable induction system, the V-
VIS (Volvo Variable Induction Sys-
tem) and an extractor type exhaust
manifold. Since this is located be-
t
ween the engine and the firewall, the
position of the catalyst could be close
to the engine which provides faster
warming-up of the catalyst and thus
l
ow exhaust emissions.
Among the basic development goals
for the engine concept were a high de-
gree of reliability and long service
life; high energy efficiency; easy
maintenance; rational manufacture;
compactness in size; low weight and
low noise level.
As for reliability and service life, the
engine has a life span of more than 20
years or a total driving distance of
more than 200.000 without needing
disassembly and with all vital parts in
good working condition.
Regarding high energy efficiency, the
gas flow has been optimized with the
aid of computer simulations and laser
measurement technology in order to
ensure efficient use of energy.
During the development of the en-
gine, Volvo Car Corporation service
personnel have contributed with their
know-how in order to achieve high re-
liability with a minimum of main-
tenance. A number of automatic func-
tions minimize the need for manual
adjustments:
-
Hydraulic tappets (no adjustment of
valve clearance)
- Automatic belt tensioners for cam-
shaft and auxiliary drives
- Adaptive functions of the control
systems compensating for system tol-
erances and wear, temperature and
fuel variations ensuring optimum fuel
metering and ignition timing
- Automatic idling speed adjustment
and air/fuel ratio

six which is installed longi-
tudinally in the rear-wheel driven
Volvo 960. Both versions clearly
illustrates the rational and flexible
manufacture of a modular engine
system.
The major components for the five
and six cylinder engines are machined
in a common transfer line in the Vol-
vo Skovde plant. This new plant is
part of the investments carried out by
Volvo for the 90's and which also in-
clude the complete Volvo 850 car.
A large number of the components
are identical for both engine versions:
pistons, rings, gudgeon pins, con rods,
bearings, seals, valve guides, valve
seats, valve springs, tappets, water
pump, camshaft drives and covers,
auxiliary drive and brackets.
Components machined in common

Technical solutions
Cylinder block and lower
crankcase
Figure 5
The cylinder block and lower crank-
case are manufactured of high-
pressure die-cast aluminium. Based on
FEM (Finite Element Method) analy-
sis and simulation, the block has been
designed to produce a compact and
rigid engine, featuring extremely low
noise and vibration emissions. The
lower crankcase, with its integrated
cast-in reinforcements in the main
bearing caps, and cylinder block to-
gether form a very compact and rigid
unit. Furthermore, the walls of both
sections have been given a reinforced
ribbing structure in order to minimize
panel vibrations and the transmission
of noise.
The grey iron cylinder liners are
cast-in during the high-pressure die-
cast process of the cylinder block. The
liners offer high wear resistance and
reduce the risk for leaks. The pro-
duction process is also cost-effective
and environmentally friendly.
The slots between the cylinders at
the upper edge of the block have been
specially machined to minimize the
risk for ovality in the cylinders as a
result of thermal expansion.
The lower crankcase has re-
inforcements of cast nodular iron in
the main bearing caps. This mini-
mizes the increase of clearance in the
main bearing that can be caused by
thermal expansion.
During the manufacturing process,
the main bearing bores are machined
with the block and the lower crank-
case bolted together as one unit. In or-
der to ensure that the unit is tight and
stable, a liquid gasket is applied be-
t ween the two parts. They are then
joined to each other with yield-point
tightened bolts during final assembly.
Oil channels and coolant ducts are
cast in during the production of block
and lower crankcase. This obviates
the need for subsequent drilling and
machining of the channels. This de-
sign principle is very cost-effective
and well suited for series production.
Cylinder head and cam-
shaft bearing housing
Figure 6
The cylinder head is made of chill-
cast aluminium to ensure a homog-
enous material. The combustion
chambers is of the pent-roof type with
four valves per cylinder. The valves
are set at a relative angle of 58 de-
grees and flank the centrally located
spark plug (figure 7). By selecting
this valve angle it has been possible to
obtain an extremely compact combus-
tion chamber, allowing for coolant
ducts between the valves and the
spark plug.
The camshaft bearing housing has
integrated upper bearing halves and
forms the top part of the cylinder
head. The lower bearing halves are in-
tegrated in the cylinder head.
The camshaft bore is machined
with the camshaft bearing housing
and cylinder head assembled. In final
assembly, a liquid gasket is applied
between both parts in order to obtain
a tight and stable joint. Oil and cool-
ant ducts are produced in the same
way as with block and lower crank-
case.
The double overhead camshafts
and cam profiles have been designed
with the aid of computer calculations
and simulations in order to minimize
torsional vibrations in the camshaft
while at the same time retaining ex-
cellent gas flow properties. The cams
offer maximum 8.45 mm lift. At 0.1
mm lift the overlap is 24 crankshaft
degrees between the exhaust valve
closing and the inlet valve opening.
Valve diameters are 31 mm for in-
let valves and 27 mm for exhaust
valves. The valve stems are chro-
mium-plated and has a 7 mm dia-
meter.
The valve guides are cast iron. Hy-
draulic maintenance-free valve tap-
pets are used.
The cylinder head is bolted to the
cylinder block with yield-point tight-
ened bolts and a head gasket which,
like all other gaskets in the engine, is
asbestos-free.

Crankshaft
Figure 8
The rigid crankshaft
runs in six main bear-
ings and has ten coun-
terweights. It is made of forged va-
nadium-steel and is precipitation
hardened. The thrust bearing is placed
at the fifth main bearing from the front
to minimize both engine overall length
and crankshaft rear end movements.
FEM analysis has been used to op-
ti
mize the crankshaft and the vibration
damper in combination with the en-
gine block under simulated dynamic
conditions, thus giving long service
life and good comfort.
The main and big end bearing surfaces
are induction hardened, with press-
rolled fillet radii for maximum fatigue
strength. The crankshaft nose in-
corporates two sets of splines, to drive
the oil pump and the vibration damper
hub. Theses splines, and the end
thread, are all rolled in a single opera-
tion, thus combining high strength
with cost-effective production. The
bearing surfaces are finally ground in
a data controlled point measurement
grinding machine, which stops ma-
chining automatically once the correct
dimensions have been obtained.
The main bearing shells are alumin-
ium while big-end shells are lead-
bronze.
Figure 10
Figure 9
Connecting rods and
pistons
Figure 9
The connecting rods are forged from
vandium alloy steel with an effective
length of 139.5 mm. High strength is
achieved through a precipitation hard-
ening process. The rods have a 1$0
degree thrust face against the crank-
shaft by virtue of the fact that the
bearing caps are 0.7 mm narrower
than the big end of the rods.
To achieve exact radial control be-
tween con rods and con rod caps,
these parts have ground serrated joints
employing yield-point tightening
bolts without nuts.
The connecting rod small and big
end weight is controlled and kept
within very narrow tolerances by
means of a special machining opera-
tion in order to minimize engine vi-
bration.
The pistons are made of aluminium
with cast-in steel expansion control.
The piston ring package consists of
two compression rings and one oil
scraper ring.
Camshaft drive Figure 10
Camshafts and water pump are driven
by the vibration damper hub on the
crankshaft by a toothed belt. For op-
timal engine performance it is nec-
essary to ensure extreme accuracy in
camshaft timing during assembly.
This is achieved by fixing the crank-
shaft and camshaft positions with spe-
cial locking tools while the drive is
fitted and adjusted. The belt is auto-
matically tensioned by means of a
spring-loaded piston assembly which
is hydraulically damped, to maintain
constant tension and compensate for
wear and temperature variations.

Lubrication system
The oil is circulated by a rotor oil
pump of the crescent-type and has a
maximum capacity of 70 litres per
minute at 6000 rpm and 80° C oil tem-
perature. The inner rotor of the pump
is driven directly by splines on the
crankshaft. The pump design permits
a compact installation, with the oil
pump at the front end of the cylinder
block.
The oil sump (figure 11) is man-
ufactured in high-pressure die-cast al-
uminium and is equipped with cast
baffle plates and a steel windage tray
to ensure a constant oil supply and to
minimize foaming when driving hard.
Cooling system
The water pump is designed to meet
high demands for reliability and com-
pactness. The housing is integrated in
the engine block and the pump is
driven by the crankshaft via the cam-
shaft belt. It has a capacity of appr
160 litres per minute at 6000 rpm.
Shaft sealing is based on a ceramic
ring and a sintered carbon ring to
eliminate leakage.
The cooling fan is electrically pow-
ered with two speeds, regulated by the
engine's control or climate system.
Auxiliary drive and
installation Figure 12
Auxiliary units such as alternator,
power steering pump and air condi-
tioning compressor, are grouped to-
gether on the left side of the engine in
a very compact and rigid installation.
The left side was chosen in order to
protect the auxiliaries from the ex-
haust heat. The compactness makes it
possible to use the same installation
for both transverse and longitudinal
engine installations. Thanks to the ri-
gidity of the system, high strength and
low noise is achieved.
Drive is by a six-groove Poly V-
belt and tension is maintained at a
constant level by a friction damped
belt tensioner. The installation is very
cost-effective with one one tensioner
and one idler. The same components
are used for version with or without
AC-compressor. The only difference
is additional belt length.
Figure 11

Air inlet system
Inlet air is taken ahead of the radiator
and passes through the air filter and air
mass meter of hot-fim type. The air
temperature is thermostatically regu-
lated to a minimum of +10° C by mix-
ing with warm air taken from the ex-
haust manifold. The inlet air then
passes through the throttle housing.
Air inlet manifold
Figure 14
The geometry of the inlet manifold
was designed with the aid of simulated
unsteady compressible air flow. Dy-
namometer testing confirmed the com-
puter models and the result is V-VIS
(Volvo Variable Induction System). V-
VIS consists of a conventional plenum
chamber with twin inlet ducts to each
cylinder, parallel but of different
length. The compact "roll" shape
achieves good space and use of materi-
al at minimum weight.
The shorter ducts are closed by a set
of electro-pneumatically controlled
valves when the throttle is more than
80 per cent open and with engine speed
lying between 1500 and 4100 rpm. At
smaller throttle opening, or at other
revs, the valves remain open and form
part of the wall of the short ducts in or-
der to minimize flow losses. Figure 15
shows the calculated volumetric ef-
ficiencies with open and closed control
valves.

With closed control valves a negative
wave, caused by the descending piston
and the inertia of the gas in the longer
duct, accelerates the air column in the
duct. At resonance rpm the inertia
causes the air to ram into the cylinder
just before the inlet valve closes. This
results in a considerable gain in vol-
umetric efficiency and hence in-
creased torque.
Figure 16 shows the calculated in-
stantaneous pressure variation at the
inlet valve antler full load and res-
onant rpm with open and closed con-
trol valve. The increase in pressure be-
tween BDC and inlet valve closing is
clearly visible.
The V-VIS system thus provides a
major increase in engine torque in the
most used medium range of engine
speed during normal driving. The sys-
tem requires an absolutely tight clo-
sure of the valves to work effectively.
This is achieved by using stainless
steel valves with soft heat resistant
rubber sealing lips. These form a tight
seal against the cast wall of tine ducts,
thus avoiding expensive internal ma-
chining of the ducts.
Control information is fed from the
throttle potentiometer and the ignition
system to a solenoid valve which con-
trols the vacuum driven servo unit to
operate the split valve spindles via a
torque balanced beam. This also to aid
tight valve closure (figure 17).

Max output for the B5254F is 170 hp
(125 kW) at 6000 rpm. Max torque is
220 Nm at 3300 rpm. Thanks to the
V-VIS system, 90 per cent of the
maximum torque is available between
2000 and 6000 rpm.
Exhaust system
Figure 18
The exhaust manifold is a welded ex-
tractor design. Five separate pipes,
each with appr 400 mm length, com-
bines performance with low weight
and short light-off time. The choice of
materials is a combination of ferritic
and austenitic stainless steel qualities.
The manifold is connected to the ex-
haust system by a flexible joint and
springloaded bolts. The system has
one main silencer and a combined
catalytic converter and silencer. The
location of the main silencer
is in the
middle of the exhaust system to en-
sure good attenuation at low fre-
quences. The silencer inside the cat-
alytic converter is located behind the
catalytic area for the same reason.
The entire system has been fine-tuned
in order to retain an "appealing" en-
gine sound which enhances the ex-
perience of driving pleasure but sup-
press noise. The tail pipe ending is of
large diameter pipe and straight.
Figure 18

Engine control systems
The B5254F-engine is controlled by
t
wo advanced electronic control sys-
tems, the LH 3.2 fuel injection
system
and the EZ 129K ignitlon system.
These systems are further develop-
ments of the well known systems used
in the current four-cylinder Volvo
cars.
The development goal has been to
produce a completely integrated sys-
tem, based on the current components,
which is less expensive, more flexible,
more reliable and more efficient. A
new cable harness concept is used,
and the engine control units include
the functions of a number of elec-
tronic relays to reduce the number of
components (figure 19).
Fuel injection system
L H3.2
The system has a new air mass meter
of hot-film type. Together with an an-
gular position throttle potentiometer,
it
gives an accurate air mass measure
at low cost. It has a closed-loop lamb-
da control and an idle speed control,
both with adaptive functions.
Previously each system in the ve-
hicle has had its own temperature sen-
sor for coolant temperature. On this
engine, however, there is only one
sensor of so-called NTC-type. This
signal is used by the LH3.2 to form a
period-time modulated signal to all
other systems which need this in-
formation.
While the electronic control unit
has been moved from the passenger
compartm
ent to the engine compart-
ment, the fuel pump relay has for safe-
ty reasons been replaced by an elec-
tronic type. It is kept triggered by the
control unit with a constant pulse
train, instead of just a "high" or "low"
signal. This is also for safety reasons
to avoid the possibility of petrol leak-
age in the engine compartment caused
by a broken fuel pipe and a running
fuel pump after a crash.
Ignition system EZ129K
To measure the engine speed and an-
gular position, a flywheel speed sen-
sor of inductive type and a camshaft
position sensor of Hall-effect type are
used. The system has two knock-
sensors for best performance of the ig-
nition timing regulation of each cyl-
inder, with adaptive functions. The
electronic control unit also controls
the V-VIS system plus the air condi-
tioning compressor and the electric
cooling fans.

the vehicle by carefully selecting the
engine mounting system. The mount-
ing system for the Volvo 850 has
been designed on the following
grounds:
- The two main engine mounts
(hydromounts) are located at the node
for the vibrations. This means on a
line through the centre of gravity for
the powertrain.
- By using soft support at the front
of the engine, the engine is kept in
balance while the main mounts do not
carry bending loads.
- By using two nonlinear reaction
rods, extreme loads from the drive
shafts are taken care of.
When designing the engine mount-
ing system great attention was taken
to the engine vibration characteristics.
The engine mounting consists of a
two-way insulation system, where
two main hydromounts, one support
mount and the lower torque reaction
rod are mounted to a rubber insulated
subframe (figure 20). This gives an
excellent insulation of engine vibra-
tions.
The main mounts and the torque
reaction rods are located in positions
with low displacement amplitude of
vibration. The dynamic stiffness of the
mounts is low to give a good vibra-
tion isolation
for small displacement
amplitudes. Large displacement am-
plitudes from the chassis are damped
by the hydraulic system of the hydro-
mounts, which is essential for a good
ride comfort.
Due to the engine vibration char-
acteristics, the displacement am-
plitude of vibration is larger in the po-
sition where the support mount is
located. Therefore it has progressive
characteristics with a low initial dy-
namic stiffness .
The main purpose of the torque re-
action rods is to restrict the engine
motions due to the torque of the en-
gine. Their characteristics are softly
progressive with a low initial stiffness.
Engine vibration levels
The firing order of the B5254F is
1-2-4-5-3, with even firing interval of
144 crank degrees.
Both theory and practical ex-
perience show that there are primarily
two vibration characteristics which
must be considered when installing
the engine in a car. The engine is ex-
cited by a first order of rotating inertia
couple with magnitude
From the principal vibration pattern
due to these excitations, it is possible
to minimize the disturbance input to

The B5254F has been developed to
meet the high demands on engines in
a car, typified by the Volvo 850 GLT
by using modern CAE technology.
The result is a compact and light-
weight in-line five-cylinder engine,
characterized by excellent per-
formance and torque, good fuel econ-
omy and a remarkable comfort level.
The manufacturing process, based on
extremely high demands for accuracy
and quality to guaranteed engine re-
liability, is particularly cost-effective
since both the five and six cylinder en-
gines were designed and developed as
a modular engine family with a con-
siderable degree of integration.

Volvo 850 GLT Engine specifications
Type:
Transverse 5-cylinder in-line
Displacement:
DOHC all-aluminium
V-VIS Volvo Variable Induction
System
2435 cc
Bore x stroke:
83 x 90 mm
CR: 10.5:1
Valves: 4 per cylinder, angled at
Max output;
58 degrees
170 hp (125 kW) at 6000 rpm
Max torque:
220 Nm at 3300 rpm
Fuel system:
LH Jetronic 3.2
Ignition system:
EZ 129K
Emission control:
Three-way catalytic converter,
Electrical system:
electrically heated lambda-sond,
vacuum controlled evaporation
system
Alternator 100 amp. Battery
440/520 amp
Weight; 153 kgs
Fuel consumption: Sweden average 0.89 litre per
Top speed:
10 km with manual gearbox,
0.91 litre per 10 km with
automatic transmission
Europe R15 12.4 litres per 100
km with manual gearbox
12.9 litres per 100 km with auto-
matic transmission
90 km/h 6.6 litres per 100 km
with manual gearbox
215 kph manual, 205 kph aut
Acceleration:
0-100 kph: 8.9 sec manual,
9.6 sec aut