Opel 1900 1973, Service Manual, Page: 413 / 625

52 1973 OPEL SERVICE MANUAL
CCUMULATOR
D R I V E :
7633
Figure 1 2 Accumulator Valve
The ports and spools operate as previously described.
However, for increased engine torque, it is necessary
to increase the accumulator pressure. This is accom-
plished by introducing modulator pressure to the
small end of the 1-2 accumulator valve. As the
modulator pressure increases, it adds to the spring
force and increases the l-2 accumulator pressure.
The 1-2 accumulator pressure is fed to the bottom
(spring loaded side) of the 1-2 accumulator piston.
The Governor is mounted on the output shaft and
contains two interconnected regulating valves See
Figure
Its purpose is to supply an oil pressure
GOVERNOR SECONDARY VALVE
SPRING RETAINER
2. GOVERNOR SECONDARY VALVE SPRING
3. GOVERNOR SECONDARY VALVE
4. GOVERNOR PRIMARY VALVE
GOVERNOR BODY
ROLL PIN
Figure Governor Assembly
that is a function of output shaft or car speed. Line
pressure is supplied to the governor from the Manual
Valve (to be covered later). The governor operates on
the principle of centrifugal force. That is, as an object
spins off center at changing speeds, its outward force
is a function of the rotating speed.
Line pressure is directed to the outer-most port of the
secondary valve. The secondary spring holds the
valve in an outward position so that the outer spool
of the valve is open to “line”. As the line pressure
builds up between the spools, it exerts a force on the
larger diameter inner spool to start counteracting the
spring. When the hydraulic force is large enough, it
moves the valve inward against the spring force until
the outer spool closes the line port. If the pressure
between the spools still creates a force larger than the
spring force, the valve will continue to
inward
until the excess pressure opens to the exhaust port.
The valve then regulates between the line and ex-
haust port.
A fixed governor pressure in the secondary valve has
now been established with no rotation of the output
shaft. As the governor begins to rotate, the outward
force (due to the weight of the secondary valve) is
added to the force of the spring. Therefore, as the
speed increases, the outward force and in turn the
secondary valve pressure increases.
The secondary valve pressure is directed to the feed
port of the primary valve. With no rotation of the
governor, the pressure acts against the large inner
spool and forces it to open to the exhaust port. Since
there is no spring force on the primary valve, it will
continue to keep the feed port closed and the exhaust
port open. The final governor pressure is then zero.
As the governor begins to rotate, the weight of the
primary valve creates an outward force working
against the oil pressure. The pressure in the primary
valve port now increases as a function of speed. This
continues up to the speed where the outward force
finally holds the primary valve outward, keeping the
feed port open.
In summary, at zero speed, the governor pressure is
zero. As the speed increases, the governor pressure
will increase as dictated by the primary valve until
the speed is great enough to hold the primary valve
all the way out. At speeds above this point, the gover-
nor pressure is established by the secondary valve.
Governor pressure is then directed to:
Modulator Valve.
1 Two Shift Valve.
2 Three Shift Valve.
3 High Speed Downshift Timing Valve.