7.3.3. Fuel feed pump
1) General descriptions and construction
The P-type injection pump is mounted with NP-FP or KD-PS type feed pump. These pumps
have the same basic construction and operation, and the general descriptions of the KD
type pump are given below:
The figures show its construction (right figure) and operation (below figure). The piston in
the fuel feed pump is driven by the push rod and tappet via the camshaft of injection pump
and performs reciprocating operation to control the suction and delivery of fuel. When the
cam reaches the Bottom Dead Center as shown in the figure, the fuel is drawn in through
the check valve on the inlet side.
The fuel pressurized as the cam rotates on flows through the check valve on the outlet side
as shown in (B). If the feeding pressure increases abnormally, the spring is compressed,
resulting in interrupting further delivery of fuel as shown in (C).
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