Bosch 0445120121 Common Rail Fuel Injector Assembly

The Bosch 0445120121 is a solenoid-actuated common rail fuel injector designed for Cummins heavy-duty diesel engines including ISLe, ISL, ISL9, QSL, and QSB series. It features the DLLA142P1709 nozzle assembly calibrated for high-pressure direct injection up to 1800 bar, ensuring optimal fuel atomization, combustion efficiency, and emissions compliance. Constructed with hardened alloy steel internal components and high-temperature resistant solenoid windings, the injector assembly withstands extreme cylinder pressures and thermal cycling typical in construction machinery and commercial truck applications. The unit serves as a direct replacement for Cummins OEM part numbers 4940640 and C4940640, and interchanges with Bosch service number 0986AD1047. Applications span hydraulic excavators, dump trucks, and heavy-duty trucks powered by Cummins ISLe, ISM, QSM, QSK, and NTA engine platforms.