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ROCHESTER CARBURETORS Bulletin 9D-5 August, 1951 |
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9D-5
August, 1951
Model "AA"
Page 5
ROCHESTER PRODUCTS DIVISION, GENERAL MOTORS CORP., ROCHESTER.
NEW YORK
join with the fuel being
delivered by the nozzles. Thus, although the nozzles suction is increased
by throttle opening, the fuel/air mixture to the engine remains constant
throughout the Part Throttle range. |
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HIGH SPEED SYSTEM (POWER
SYSTEM)
To achieve the power mixtures
needed for wide open throttle operation the Rochester Products Carburetor
employs a vacuum operated power diaphragm, stem and calibrated spring
located in the Cover and the Power Valve in the Bowl. This system is built
upon the principle that sudden acceleration is always
accompanied by an immediate corresponding decrease in intake manifold
vacuum. A direct vacuum passage "M" through the carburetor throttle body,
outer housing, and cover to the intake manifold insures instantaneous
diaphragm action to operate the power system. |
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Figure 4. Power System |
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Attached to the Cover of the
carburetor is the
neoprene diaphragm, stem, and
calibrated spring assembly "J". Directly underneath the stem in the Bowl
is the power valve "K", pressed into the connecting passages between the
power valve and the main metering jets are the calibrated power
restrictions "L". At any manifold vacuum above 8" the diaphragm is held
"UP" by vacuum which in turn holds the stem above the spring loaded
plunger in the power valve, so that no fuel passes through this valve.
Opposing this suction is the power spring surrounding the stem. This
calibrated spring at any vacuum lower than 8" forces the stem down, which
unseats the spring loaded plunger in the power valve, permitting fuel to
pass through the power valve. This fuel is then metered by the power
restrictions "L" and joins with the fuel from the main metering
jets to be delivered to the engine. |
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