| 摘要 |
<p>A dual metering valve for a diesel engine pilot fuel injection system. The dual valve includes a pilot fuel metering valve, a main fuel metering valve, and a logic system. The pilot and main valves are of the spool type and each includes a solenoid for axially moving the spool from an unactuated position to an actuated position and a spring which returns the spool to an unactuated position when the solenoid is de-energized. The logic system controls the supply of unmetered fuel to a chamber in each spool and utilizes the position of the spools to provide the logic control. When the main spool is in its unactuated position it ports unmetered fuel to the pilot spool chamber; when the main spool is in its actuated position it blocks the supply of unmetered fuel to the pilot spool chamber. Pilot spool control is the reverse of the main spool control; i.e., when the pilot spool is in its unactuated position it blocks the supply of unmetered fuel to the chamber in the main spool; when the pilot spool is in its actuated position its ports unmetered fuel to the main spool chamber. The logic allows fuel metering when the spools move from their unactuated positions to their actuated positions. The logic prevents fuel metering when the spools move from their actuated positions to their unactuated positions. The pilot and main spools are each provided with a diaganol shoulder and means to vary the angular position of the spools and diagonal shoulders to control amounts of fuel metered by the valves.</p> |
