TL960 SERVICE MANUAL
the pulse from the ECM and how long it keeps the solenoid energized. As long as the solenoid is energized and the poppet valve is off its seat, oil continues to push down the intensifier and plunger until the intensifier reaches the bottom of its bore.
Since the HEUI injector is the heart of the system, let's look at its operation in detail.
The HEUI injector is hydraulically actuated by high pressure engine oil supplied by the high pressure oil pump. It consists of four major components:
1. Solenoid: The solenoid is a very fast acting electromagnet which, when energized, pulls the poppet valve off its seat.
Poppet Valve: The poppet valve is held on its seat by a spring. In this closed position, high pressure inlet oil is blocked and the intensifier cavity is opened to drain. When the solenoid is energized, the poppet is quickly lifted off its seat. The path to drain is closed and the inlet for high pressure oil is opened.
Intensifier Piston and Plunger: When the poppet valve opens the inlet port, high pressure oil enters the injector and acts on the top of the intensifier piston. Pressure builds on the intensifier, pushing it and the plunger down. The intensifier is six times larger in surface area than the plunger, providing six times