PRINCIPLES GASOLINE/DIESEL FUEL SYSTEMS - OD1620 - LESSON 2/TASK 2
FIGURE 52. PRESSURETIMED INJECTION SYSTEM.
(c) A return line from the PTG pump to the fuel tank is provided
to bleed off excess fuel so that operating pressures can be regulated.
(d) The PTG pump delivers controlled amounts of fuel to pressure
timed delivery (PTD) injectors.
(e) Delivery of fuel to the PTD injectors is through a commonrail
type delivery line.
(f) A commonrail type return line connects the PTD injectors to
the fuel tank so that excess fuel may be diverted back to the fuel tank.
(2) PTV Injection Pump (figure 53 on the following page). The PTG
pump is driven directly by the engine at a onetoone speed ratio. The pump
contains four main components. These four components and their operations
are described as follows:
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