Governing System; Carburetor; General Description - Daewoo G424 Gasoline Service Manual

GOVERNING SYSTEM

General Description

Sectional View of Air Governor
(1) Body. (2) Stabilizer rod. (3) Stabilizer piston. (4) Throttle plate. (5) Throttle plate shaft. (6) Bearing. (7) Nipple. (8) Spring.
(9) Bush nut. (10) Adjusting screw. (11) Plate. (12) Cam
The air governor is located to the underside of the
carburetor. It serves to protect the hydraulic pump, to
limit the maximum traveling speed of the vehicle, and
to prevent excessive increase of engine speed.
1. Governing operation
The throttle plate shaft is offset from the center of
the governor bore. Also, the full-open position of
the throttle plate does not coincide with the truly
full-open position, but rather leans to the closing
side. Therefore, the pressure of mixture flow acts
on the throttle plate to rotate it in direction of
closing, causing a torque to its shaft.
The torque stretches the return spring attached to
the cam on the throttle plate shaft until the torque
balances the tension of the spring, and the throttle
plate is maintained at that open angle.
This is governing operation. That is, a balance
between the pressure applied to the throttle plate,
which depends on vacuum pressure, and the
spring tension keeps the throttle plate at position
between the full-open position and the full-close
position to control the amount of mixture flowing
into the engine.
G424 Service Manual
2. Auxiliary operation
The throttle plate opening angle of this governor is
set under the full-open condition of the carburetor.
Accordingly, when the carburetor throttle valve is
operated in the direction of closing, governor
pressure applied to the throttle plate decreases
and, therefore, the throttle plate is rotated by the
spring in the direction of opening. As a result,
engine speed increases. To prevent this, the
governor is provided with a stabilizer piston.
The stabilizer piston acts to close the throttle plate
when a large vacuum pressure is developed on
the upper side of the throttle plate, so that proper
opening of the throttle plate can be maintained in
combination with the opening of the carburetor
throttle valve. With the help of this auxiliary
operation, the governing operation can follow up
the variations of load quickly.
103 Governing System