Volvo 164 Owner's Manual - page 31
TECHNICAL DESCRIPTION
Exhaust emission control
The engine is fitted with an exhaust emis-
sion
control
system
which produces a
more exact and leaner mixture ratio be-
tween fuel and air resulting in a more com-
plete combustion and thereby cleaner ex-
haust gases.
The system on the B 30 A engine consists
of specially adapted carburettors and an
i ntake manifold provided with a preheat-
i ng chamber and control throttles.
When driving at low speed, the throttles
are closed so that the fuel-air mixture
passes the preheating chamber.
When higher output is required, the throt-
30
tles open and fuel flows directly to the cy-
li nders.
On the B 30 E, exhaust emission control is
provided by the electronic fuel injection
system.
Cooling system
The cooling system is of the sealed pres-
sure type and incorporates a circulation
pump.
When the engine is cold, the coolant cir-
culates only inside the engine. As the en-
gine warms up, a thermostat valve starts
opening the outlet to the radiator.
An expansion tank prevents air from cir-
culating with the coolant as this would
cause corrosion in the cooling system. The
fan is driven via a slip coupling which
keeps the fan speed at about max. 2 500
rpm.
POWER TRANSMISSION
Clutch
The function of the clutch is to transmit
the power from the engine to the gearbox.
The clutch is of the single dry plate type.
Pressure on the pressure plate is obtained
from a diaphragm spring which in turn is
controlled mechanically by the clutch pe-
dal via the trove-out yoke. (Hydraulic ope-
ration for vehicles with right-hand drive.)