Operation Section
1
–
34
Normally Closed Type
- When the solenoid is energized, the needle valve is pressed upon (in the compact SCV, the cylinder is pulled upon)
by the armature, completely opening the fuel passage and supplying fuel to the plunger. (Total quantity suctioned
→ Total quantity discharged)
- When power is removed from the solenoid, the return spring presses the needle valve back to the original position,
closing the fuel passage.
- The solenoid ON/OFF is actuated by duty ratio control. Fuel is supplied in an amount corresponding to the open
surface area of the passage, which depends on the duty ratio, and then is discharged by the plungers.
Duty Ratio Control
- The engine ECU outputs sawtooth wave signals with a constant frequency. The value of the current is the effective
(average) value of these signals. As the effective value increases, the valve opening increases, and as the effective
value decreases, the valve opening decreases.
Q002343E
Cross SectionExternal View
Return Spring
Solenoid
Valve Body
Needle Valve
Conventional SCV
Q002323E
Cross SectionExternal View
Return Spring
Solenoid
Valve Body
Needle Valve
Compact SCV
Q000844E
Average Current Difference
Actuating Voltage
ON
OFF
Current
High Suction Quantity Low Suction Quantity
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