DESCRIPTION & OPERATION
Page 35
High-Pressure Fuel System
The high-pressure fuel system (Figure 37) is
designed to provide fuel to the combustion
chamber under high pressure. In this system, unit
pumps (one per cylinder) replace the previously
used fuel injection pump. The unit pump
operating pressures are 26,000 psi, more than
50 percent greater than the peak injection
pressures of the E7 engine. These higher
pressures, along with an extended timing range
and optimized timing control, provide
performance improvements.
Fuel is supplied to each of the unit pumps by the
fuel supply gallery in the cylinder block. The high
pressure required for fuel injection is generated
by a pump plunger (10 mm diameter, 18 mm
stroke), which is actuated by a roller cam follower
(tappet) driven by the engine camshaft. The
volume of fuel delivered to each cylinder is
precisely metered by a solenoid mounted on
each of the unit pumps, which responds to
signals from the V-MAC III EECU. The
pressurized fuel is delivered to the injector
nozzles by individual fuel injector lines, which are
the same for all cylinders and all E-Tech™ engine
models.
37
Figure 37 — High-Pressure Fuel System
5_106_00.bk Page 35 Friday, August 4, 2000 11:17 AM
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