The fuel pump assembly consists of a low-pressure
transfer pump and a high-pressure fuel injection
pump. The pump assembly is driven from a gear in
the front timing case at engine speed. The fuel
injection pump (1) has two plungers that are driven
by a camshaft. The fuel injection pump (1) delivers a
volume of fuel two times for each revolution. The
stroke of the plungers are fixed.
The injector will use only part of the fuel that is
delivered by each stroke of the pistons in the pump.
The suction control valve (3) for the fuel injection
pump (1) is controlled by the ECM. This maintains
the fuel pressure in the fuel manifold (rail) at the
correct level. A feature of the fuel injection pump (1)
allows fuel to return to the tank continuously.
The fuel temperature sensor (2) measures the
temperature of the fuel. The ECM receives the signal
from the fuel temperature sensor (2). The ECM
calculates the volume of fuel.
The fuel injection pump has the following
operation:
• Generation of high-pressure fuel
The fuel output of the fuel injection pump is controlled
by the ECM in response to changes in the demand of
fuel pressure.
Shutoff
The engine shuts off by preventing the electronic unit
injectors from injecting. The ECM then closes the
suction control valve to prevent the pressure in the
fuel manifold (rail) from increasing.
UENR4490-01 45
Engine Operation
This document has been printed from SPI2. NOT FOR RESALE
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