Honda LEAD 110 2009 Service Manual page 42

FUEL ENRICHMENT FOR QUICK ACCELERATION
ENGINE CONDITION UNDER QUICK ACCELERATION:
When throttle valve is opened suddenly, excess volume of intake air flows into the engine. Smaller intake manifold vac-
uum pressure causes lack of fuel and air-fuel ratio becomes lean, resulting in temporary lack of engine power.
QUICK ACCELERATION WITH CARBURETOR:
When throttle valve is opened abruptly, the vacuum piston responds rather slowly, causing larger vacuum pressure in ven-
turi, resulting in more fuel drawn out from main nozzle. This supplemental fuel produces ideal air-fuel ratio.
FUEL CONTROL CIRCUIT
THROTTLE VALVE
QUICK ACCELERATION WITH PGM-FI:
When throttle valve is opened abruptly, ECM regulates the amount of fuel according to output voltages from TP sensor,
depending on engine condition. The injector is kept open longer than usual in order to send more fuel into the cylinder,
producing ideal air-fuel ratio.
SLOW PORT
MAIN CIRCUIT
SLOW CIRCUIT
IDLE CIRCUIT
IDLE PORT
BASIC DISCHARGE
DURATION
CORRECTED
(ADDED)
DISCHARGE
DURATION
FOR QUICK
ACCELERATION
TECHNICAL FEATURES
MAIN NOZZLE
CARBURETOR
INJECTOR
PGM-FI THROTTLE BODY
THROTTLE VALVE
2-5