E.C.C. (Electronic Controlled Carburetor) System Description

E.C.C. (Electronic Controlled Carburetor) SYSTEM

DESCRIPTION E16S for non-California
Idle Speed Control System (Cont'd)



(1) When the engine is stopped. The leak orifice is closed by the return springs
of the power diaphragm chamber and control diaphragm chamber.



(2) Soon after the engine is started. The control vacuum produced in the vacuum control modulator valve goes to the control diaphragm chamber. Therefore the position of the valve A is determined by the strength of the control vacuum. On the other hand, the power diaphragm chamber is moved downward by the intake manifold vacuum. However, the leak orifice is opened and the intake manifold vacuum in the power diaphragm chamber is weakened because the atmospheric presure goes to the power diaphragm chamber. Then, the power diaphragm
is moved upward until the tip of the push rod contacts the valve A.
(3) When the engine is cold It is necessary to run the engine at fast idle speed to warm it rapidly. Lower control vacuum is made in the vacuum control modulator valve by the signal from the E.C.C. control unit and the position of valve A is determined by the lower control vacuum. The push rod is set at point A. Consequently, the throttle valve is opened wide to run engine at high idle speed.



(4) When the engine is hot Higher actuating vacuum is made in the vacuum control modulator valve by the signal
from the E.C.C. control unit and the push rod is set at point B. The throttle valve is closed to decrease the idle speed.



^ Relationship between the control vacuum and push rod stroke.






FAIL-SAFE SYSTEM

A fail-safe system is operated when any of the vacuum hoses connecting idle speed control actuator with vacuum control modulator is disconnected or cut off due to an accident.
If vacuum hose between idle speed control actuator and vacuum control modulator is disconnected, vacuum switch detect atmospheric pressure and cut off electric supply to vacuum cut solenoid valve. The air passages between (M) and
(N) become open, thus atmospheric pressure through air filter is led to power diaphragm chamber to stop idle speed control actuator from opening throttle valve.