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Instruction Book for Bolinder Single & Twin-cylinder Engines
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Fuel System
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The
fuel system consists of fuel tank, pipe-filter,
injection pump, injectors and piping. As extras the
engine can also be fitted with feed pump and overflow
valve. |
Fuel System
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1
Fuel tank
2 Fine filter
3 Injection pump
4 Injector
5 Leak off pipe
6 Cut out lock
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From the
fuel tank 1, fig 9, the fuel self-feeds through the
fine-filter 2 to the fuel chamber of the
fuel pump3. This constant-stroke pump has one plunger
for every engine cylinder so that every
pump has as many elements as there are cylinders in the
engine. These pump elements are
actuated by special cams on the camshaft, which rotates
at half engine speed. The plungers force
the fuel through the pressure pipes to the injectors 4.
The pressure pipes are connected to the
injectors by special unions containing an edge filter.
This filter serves to stop any particles which
may get into the pipes when they are removed from the
engine.
From the injector nozzles the fuel is sprayed into the
engine cylinders through four holes. The
high opening pressure atomises the fuel completely to
ensure starting even if the engine is cold.
Leak off oil from the nozzles is piped back to the
filter. On engines with feed pump the leak-off
fuel is led from the injectors to the overflow valve and
from there back to the fuel tank.
As previously stated, the pump element works with a
constant stroke. To permit variations of the
fuel quantity supplied by every stroke so that it
corresponds to the load on the engine at every
particular moment, the pump element has been given a
special shape. This design allows
variation of the injected fuel quantity by rotation of
the pump element. Rotation is controlled by
the engine governor. |
Fuel system with feed pump
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1
Feed pump
2 Cut-out cock
3 Fuel tank
4 leak off pipe
5 Injector
6 Injector pump
7 Overflow valve
8 Fine-filter
9 Return pipe line to fuel tank |
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The
governor 2, fig 11, of this engine is of the centrifugal
type and driven from the camshaft. The
governing weights 1 act on the shaft 8 towards the lever
9. In its turn, this lever acts on the
injection pump 11 so that the pump element rotates. |
Governor
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1
Governing weights
2 Governor
3 Spring
4 Speed control
5 Ratchet
6 Pawl
7 Tensioning arm
8 Shaft
9 Lever
10 Stop control
11 Injection pump
12 Cold-start device
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If
engine r.p.m. increases, due to decreased load, the
weights move outwards and compress the
spring 3. The shaft then actuates the lever 9 and thus
also the fuel pump so that the effective pump
stroke shortens. The amount of fuel injected then
releases in proportion and the engine r.p.m.
drops until it corresponds with the set speed.
When engine r.p.m. decreases the governor works
conversely. The speed control 4 can be used to alter
spring pressure on the shaft 8 and vary the
speed of the engine.
The governor is fitted with a cold-start device 12 to
ensure engine starting even at low
temperatures. Depression of the cold-start button
enables the injection pump to supply extra fuel
at the starting instant and thus facilitate starting.
The button returns to it's initial positions as soon as
the engine has started. Under no
circumstances whatever may it be locked in the depressed
position while the engine is running;
this might otherwise cause severe damage to the engine.
For engine stopping the governor is
fitted with a special device 10, which acts on the
injection pump control rod set the pump for zero
feed. The fuel enters the injector through the pipe 1,
fig. 12, passes the edge filter 2 |
Fine Filter
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1 Pipe to injection pump
2 Air vent screw
3 Pipe from fuel tank
4 Filter insert
5 Leak off pipe
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and is
led through the passage 3 down to the nozzle 4. When
fuel pressure reaches approx 1,920
lb/sq.in. (135 kg/sq.cm) the nozzle 5 lifts from it's
seat and the fuel is sprayed into the cylinder through
four holes. Leak-off fuel from the injector is carried
back to the overflow valve on the filterand from there to the fuel tank. |
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