SMOOTH, FAST DIRECT LIFT CONTROL
The essentials of the test hardware -- a modified production OEM injector. Its solenoid and servo valve were removed and replaced with a GPDT magnetostrictive actuator providing direct control over the needle. The needle is a conventional needle that opens nozzle holes. A fiberoptic probe directly measured needle lift. In reviewing the test data below, it is important to note that the total mass that was accelerated and decelerated in this test-only device was 90 grams.
The needle lift traces at left demonstrate continuously variable opening and closing rates.
In the graph at right, continuously controllable magnetostrictive force and speed were used to show how small measurable fuel dots could be despite its 90 grams of accelerated mass. The red trace is no measurable fuel was injected into a test apparatus, the blue trace is a small "dot" of fuel, and the tan trace is a smallish "dot."