Caterpillar 35A Series Fuel Injector
Engineering Design and Operation
These fuel injectors are designed around HEUI (Hydraulic Electronic Unit Injector) or MEUI (Mechanically actuated Electronic Unit Injector) architecture depending on the variant, offering electronically modulated injection timing and quantity control under high pressures.
Key Engineering Features:
Injection Pressure: Up to 1600 bar (160 MPa)
Spray Nozzle Orifice Size: Typically 0.2–0.8 mm
Nozzle Configuration: Single-hole, multi-hole, orifice plate (depending on cylinder head design)
Solenoid Resistance: Low-impedance (2–3 Ohms) or high-impedance (13–16 Ohms) variants
Material Composition: High-carbon steel and carbide-coated wear surfaces to withstand high-pressure cycles and thermal stress
Fuel Control: Pulse-width modulated solenoid control with ECU-trimmed fuel mapping
Engineering Design and Operation
Functionality and Role in Engine Performance
Fuel injectors in the 35A Series ensure:
Precision fuel metering across wide engine load conditions
Enhanced atomization for improved combustion efficiency
Reduced emissions (NOx, PM) through optimized spray pattern
Extended injector lifespan via hardened needle valve and plunger assemblies
Injector Part Numbers and Compatibility
|
Injector Part No. |
Replacement Code |
Compatible Engines |
Notes |
| 7E-8836 | – | 3508A, 3512A, 3516A | Factory-new OEM injector |
| 392-0202 | 20R1266 | 3506, 3508, 3512, 3516, 3524 | Requires ECM trim code update |
| 20R1270 | – | 3508, 3512, 3516 | OEM part for Tier-1 applications |
| 20R1275 | 392-0214 | 3500 series engines | Remanufactured to CAT spec |
| 20R1277 | – | 3520, 3508, 3512, 3516 | High-load performance stability |
