Description to Weichai Generator Set Diesel Engine System
by Starlight Generator dieselgeneratortech2.1 Gear
system and valve mechanism of Weichai Generator Set Engine
The
valve mechanism comprises camshaft gear, camshaft, tappet, push rod and valve
train, and it adopts a structure of overhead valve and underneath camshaft.
Camshaft
gear1 is driven by crankshaft gear 6 through idle gear 2, and crankshaft gear 6
also drive fuel injection pump 3 through idle gear 2.The gears should be
assembled according to the paired engagement marks. Each gear is marked with
“.”, and the gears must be assembled with “.” marks aligned to ensure that the
valve timing and fuel supply time are correct, as shown in Figure 2-1.
Driven
by the camshaft gear, the camshaft controlsthe opening and closing of intake
and exhaust valves according to certain valve timing through the tappet and
push rod.
2.2 Lubricating system
Lubricating
system consists of oil strainer, oil pump, oil filter and all internal pipes.
The diesel engine adopts a combined lubrication method: pressure lubrication
and splash lubrication.For crankshaft main bearing, connecting rod bearing,
camshaft bearing and rockshaft and other parts, pressure lubrication is
adopted.Besides, some kinematic pairs, such as cylinder liner and piston,
piston pin and connecting rod, and piston pin seat, valve and valve guide, gear
and other parts rely on splash lubrication.
Oil
is intake by oil pump through filter screen, and compressed into oil
filter.Filtered oil lubricates the crankshaft main bearing, camshaft bearing
and rocker arm bearing through engine block main oil gallery.Lubricate the
connecting rod bearing through oil gallery in the crankshaft.
Oil
filter adopts a totally-closed spin-on type, during operation, if filter
element is blocked, the safety valve will automatically open and make oil flow
into main oil gallery directly, but at this moment, it has lost its function of
filtration, therefore, it is required to timely replace filter elements of oil
filter according to "Technical Maintenance" requirements. A pressure
regulating valve is set in the oil filter, which can adjust pressure in the
main oil gallery, maintaining it within the range of (200~500) kPa.
2.3 Fuel system
Fuel
system consists of fuel tank, coarse fuel filter, fuel delivery pump, diesel
filter, fuel pump and fuel injector.The diesel enters into fuel delivery pump
through coarse fuel filter, and it is delivered by the fuel delivery pump to
the diesel filter; after further filtration, it enters into fuel pump, and the
high-pressure fuel that comes out of fuel pump is injected into combustion room
by the fuel injector; the low-pressure fuel that comes out of fuel pump and the
diesel that leaks out of needle valve couple at port of fuel injector flow back
to fuel tank, as is shown in Figure 2-2.
1.
fuel return pipe; 2. high-pressure fuel pipe; 3. diesel filter; 4. fuel tank;
5. fuel filter; 6. fuel injection pump
The
fuel delivery pump is of single-functional piston type, and installed on the
outer side of fuel injection pump, it is driven by the eccentric gear on the
camshaft of fuel injection pump, what's more, there is a manual fuel pump on
the fuel delivery pump, before start-up of diesel engine, loosen the bleeder
screw, and unscrew the manual fuel pump handle, tilt it up and down
reciprocally to pump fuel and exhaust the air, making the whole fuel pump
filled up with fuel.After finishing the air bleeding, the handle should be
screw up, in order to avoid fuel leakage.
Diesel
filter is used for separating mechanical impurities in the diesel, and reducing
wearing of plunger couple and nipple needle valve couple.Blockage or damage of
filter element, it is necessary to replace it.
The
fuel injection pump is a BQ pump, electronic governor.The fuel injection pump
is driven by fuel injection pump timing gear, through the fuel injection pump
camshaft, idler wheel and tappet, making the plunger move reciprocally in the
plunger liner. The control mechanism which changes the fuel volume is made up of
adjusting pull rod, shifting fork and adjusting arm pressed on the plunger, and
the position of pull rod is controlled by the governor, when the pull rod move
forward, the fuel supply raises, otherwise, declines.
Before
delivery of engine out of factory, the fuel injection pump has been adjusted
and lead-sealed by manufacturer; users shall not disassemble it at will.When it
is necessary to disassemble or repair, adjusting test should be conducted on
test bench for fuel pump.
The
fuel injector is of P Series, which is compressed up by a compression bolt and
a flat clamp, the height of nozzle sticking out of cylinder head bottom surface
can be adjusted with a gasket.The fuel injector should be maintained as
specified in these instructions, in which, the needle valve couple are ground
in pair, when disassembling, they shall not be exchanged, and should be kept
clean.
2.4 Cooling system
The
cooling system is forced circulation water cooling, as is shown in Figure 2-3.
It
includes radiator, water pump, fan, and thermostat and so on.When the
temperature of cooling water in engine block is lower than 73°C, the thermostat
does not open, and the cooling water is circulating inside the engine (namely
small circulation), making the temperature of water in the engine rise rapidly
so that the engine reaches thermostability as soon as possible. When the
temperature of cooling water reaches 80°C, the thermostat gradually opens, at
the same time, the small circulation is closed. Cooling water enters into
radiator through thermostat, reenters water pump after cooled by fan, and then
enters engine block, fulfilling the big circulation.
This
engine adopts centrifugal water pump, and the water pump adopts
self-lubricating inner integral ball bearing, so no need to fill in lubricating
grease. During use, when the water seal is worn, and there is serious water
leakage in the water hole below the water pump body, it is necessary to replace
the water seal.
2.5 Electric appliance
Electric
system includes storage battery, starter, alternator, relay governor, electric
lock, preheating start-up switch and ammeter, etc.
The
alternator is of JFWZ13 (14V/25A, in-built governor and reserved speed sensor
binding post) AC shunt excitation alternator.It is formed by rectifying
three-phase alternator and silicon diode, connect the negative electrode to the
earth, never connect in the opposite direction; otherwise, the alternator will
be damaged.
The
starter is a series excitation DC motor(12V/3kW) of type QDJ1408L-P.The once
continuous service time of starter shall not be longer than 10s, and the
interval between twice start-ups is 2 min, if consecutive 3 times of start-ups
all fail, it is necessary to check and troubleshoot. For the overhaul and
troubleshooting methods of starter, please refer to "Operation and
Maintenance Instructions for Starter".
The
storage battery is of type 6Q-140, and voltage is 12V. Before use, the storage
battery should be initially charged by filling in battery solution according to
the specification.During use of the storage battery, please note that:
1.
Frequently check the height of battery solution at least once a week, when the
height is lower than (10~15) mm, it is necessary to add distilled water or
other purified water, and it is forbidden to use well water or river water.
2.
Normally keep unblocked the small air hole in the nut cover over the port of
solution, and the outer surface of battery should be kept clean and dry.
3.
Normally keep the quantity of electric charge of storage battery not less than
75%.When the storage battery is discharged by up to 50%, and then it's time to
charge it. The discharging degree of storage battery can be check by aerometer
or discharging instrument.
4.
If any used storage battery will not be used again temporarily, before parking,
it should be fully charged, and be recharged once a month after that.In the
parking period, do not pour out the battery solution.
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Created on Jun 27th 2019 02:58. Viewed 366 times.