Launched in 1989, the UP units were the first diesel electronic injection system for commercialvehicles on the market. Through this system the dosage and injection of the fuel are electronicallycontrolled by a unit, which is called ecu (Electronic Control Unit). After this period, seeking an evolution,in 1994 was launched the UI system, which has as characteristic the combination of the injector pumpand the injector nozzle in a single unit.
An injector unit (UI) is an integrated high-pressure fuel direct injection system for diesel engines, combining the injector nozzle and injector pump into a single component. The used plunger pump is usually triggered by a shared camshaft. In an injector unit, the device is usually lubricated and cooled bythe fuel itself.
High-pressure injection delivers power and fuel consumption benefi ts over the previous lower pressure fuel injection, injecting fuel as a larger spray, providing a much larger proportion of surface area to volume. This provides improved vaporization of the surface of fuel droplets and therefore a more efficient combination of atmospheric oxygen with vaporized fuel, providing a more complete and cleanercombustion.
Feeder pumps are responsible for pumping tank fuel to power the injector units. Feeder pumps have a simple operating principle, where two gears rotate in opposite directions, generating a pressure on diesel oil that directs it to the injector units.
Feeder pumps have a higher pressure and flow capacity than electric pumps, and have a reinforced
construction that ensures the repair of the same instead of replacement.