Volvo Penta 300 Series, Руководство по ремонту

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13
Design and Function
Engines general
The engines are straight 6 cylinder (31/32 series have
4 cylinders), 4 stroke diesel engines with overhead
valves. KA(M)D44/300 have 4 valve technology,
other models conventional 2 valve technology. All are
directly injected and turbocharged. KA(M)D42/43/44/
300 and KAD32 also have a mechanically driven
compressor for higher power at low and mid range of
the rev curve.
The engines have wet on wet replaceable cylinder
liners and a completely new cylinder head.
Engine lubrication is covered by a press lubrication
system which uses a an effective oil pump to move
the oil through the oil cooler to the oil distribution
housing.
The oil is forced partially through the oil filter to the
engine lubricating points and partially via the piston
cooling valve to the piston cooling nozzles.
The piston cooling valve opens when the oil pressure
reaches a certain pressure and oil is injected into the
underside of the piston. The oil is routed further
through a cooling pipe into the upper part of the
piston.
The oil cooler transfers heat from the oil to the engine
cooling system.
Oil cleaning is carried out by a full-flow oil filter.
The cooling system is divided into a freshwater and a
seawater system.
The fresh water system is thermostat regulated and
cools the cylinder block and cylinder head.
The seawater system cools the freshwater system
via a heat exchanger.
The turbocharger supplies the engine with pressurized
fresh air which gives greater air capacity. This means
that the amount of fuel injected can be increased,
which gives better engine power.
The engines are equipped with seawater cooled
charge air cooler (CAC), which lower the intake air
temperature after turbo compression. This lowers the
volume of the air and more air can be supplied to the
engine. The increased air capacity further increases
the amount of fuel injected and therefore the engine
power.
By cooling the intake air, the combustion and exhaust
temperatures are also reduced despite the increased
power output.
The charge air cooler (CAC) also gives lower exhaust
emissions because combustion is more efficient
because of the higher oxygen content of the intake
air.
The turbocharger turbine housing is freshwater
cooled, otherwise the turbocharger (TC) is cooled and
lubricated by the engine oil.
KA(M)D44/300 is equipped with EDC (Electronic
Diesel Control). The system is built up around a
compressor which is continuously supplied with
information from all engine functions such as boost
pressure, throttle opening, fuel temperature etc. The
information is analyzed up to 100 times per second
and gives the processor an exact picture of the
prevailing operating conditions. The fuel supply and
alfa angle are regulated through the electronic
actuator on the injection pump.
The result is that the engine always receives the op-
timal amount of fuel in all drive conditions, which
gives faster throttle response, lower fuel consumption
and reduced exhaust emissions.