How Denso fuel injectors work:
1. Static closing stage: the electromagnet is not energized, and the hemispherical flat valve tightly seals the valve seat surface under the action of the spring force. Because the fuel introduced into cavity A and the fuel introduced into cavity B
There is the same pressure (common rail), and the hydraulic stress area on the end face of the valve stem.
It is much larger than the hydraulic force area at the end of the needle valve, so the resultant force acting on the entire moving part is downward. At this time, the needle valve seat is tight, the nozzle hole is sealed, and no fuel is injected.
2. Injection stage: The electromagnet is energized to generate an upward electromagnetic force. At this time, the electromagnetic force attracts the armature plate to move upward, and the hemispherical plate valve is in
It is pushed away under the action of high-pressure fuel, and the high-pressure fuel in the A cavity returns to the fuel quickly. a through the seat hole.
The oil pressure in the cavity drops sharply. The fuel in the B cavity of the needle valve end still maintains a pressure close to the rail pressure, so the closing and opening directions acting on the entire moving parts can prevent the fuel from easily accumulating.
When the valve is lifted, high-pressure fuel is injected into the combustion chamber through the injection hole for injection.
3. Stop spraying: Once the electromagnet stops energizing, the electromagnetic force generated by it disappears immediately, and the armature forces the hemispherical flat valve to tightly seal the seat surface of the valve seat under the action of the spring force.
At this time, the oil pressure in chamber A increases rapidly until it approaches the oil pressure in the oil rail. Under the turning of the resultant force acting on the entire moving parts, the needle valve is seated, the nozzle hole is tightly sealed, and the injection is stopped.
oil.
