HOW THE EUI WORKS
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The EUI has two essential features. One is a corn-driven plunger which generates the pressure in the fuel; the other is a quick acting electromagnetic spill valve which controls the fuel flow.
In operation, starting with the pumping plunger in the fully retracted position, fuel is fed into the injector barrel under the normal pressure of 60psi. The spill valve is open at this stage, allowing fuel to flow in and through the injector to prime the system and remove any trapped air. As the cam revolves the plunger moves down the bore, to close off the feed port and continue to expel fuel through the spill valve At the desired point, as determined by the ECU, the spill valve closes and compression of the fuel starts. Fuel pressure increases to the point where it finally overcomes the injector nozzle spring, forcing the fuel into the cylinder. Again, at the precise time decided by the ECU, the spill valve opens, the pressure collapses and the nozzle spring closes off the supply to the cylinder.