DIESEL ENGINE SPEED,
DOE-HDBK-1018/1-93
Diesel Engine Fundamentals
FUEL CONTROLS, AND PROTECTION
Detailed Operation of the Governor
With the engine operating, oil from the engine lubrication system is supplied to the
governor pump gears, as illustrated in Figure 29. The pump gears raise the oil pressure
to a value determined by the spring relief valve. The oil pressure is maintained in the
annular space between the undercut portion of the pilot valve plunger and the bore in the
pilot valve bushing. For any given speed setting, the spring speeder exerts a force that
is opposed by the centrifugal force of the revolving flyweights. When the two forces are
equal, the control land on the pilot valve plunger covers the lower ports in the pilot valve
bushing.
Figure 29 Cutaway of a Woodward Governor
ME-01
Rev. 0
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