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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

Summary of Contents for 850 GLT

Page 1: ...Technical information Engine Volvo 850 GLT ...

Page 2: ... 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...

Page 3: ...ority 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...

Page 4: ...ne and the firewall the position of the catalyst could be close to the engine which provides faster warming up of the catalyst and thus low 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 reliabili...

Page 5: ...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 dr...

Page 6: ...e 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 ...

Page 7: ...e 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...

Page 8: ...pm 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 compa...

Page 9: ...er 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...

Page 10: ...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 ...

Page 11: ...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...

Page 12: ...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 compartment to the engine compart ment the fuel pump relay has for safe ty reasons b...

Page 13: ...mplitude 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 ...

Page 14: ... 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...

Page 15: ...ission 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 ...

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