Bosch Common Rail Injector CRIN4

1. Product Information

Bosch CRIN4 is a family of Bosch common‑rail diesel fuel injectors (CRIN = Common Rail INjector, generation 4). They are high‑pressure, electronically controlled injectors used on modern diesel engines to deliver precisely metered fuel from the common rail into each cylinder.

Quick facts
– Operation: electrically actuated (usually solenoid; some families use piezo), timed by the ECU to allow multiple injection events (pilot/main/post) for cleaner combustion and lower noise.
– Purpose: provide very high‑pressure, precisely metered fuel spray for better power, efficiency, emissions control, and smoother running.
– Typical features: precision nozzle/needle, internal pressure/control chamber, return/bleed path, and electrical connector for ECU control. Calibrated flow characteristics and seat sealing are critical.
– Applications: light‑ and heavy‑duty diesel passenger cars, vans, and commercial engines using common‑rail fuel systems (various engine makers use CRIN4 variants).
– Symptoms of failure: rough idle, misfire, poor acceleration, increased smoke (black/white/blue), poor fuel economy, hard starting, injector/leak codes, or imbalance codes in diagnostics.
– Service/repair: injectors may be replaced or remanufactured; replacement often requires matching/calibration (flow testing) and sometimes injector coding/programming to the ECU.
– Identification: a full Bosch part number (and vehicle/engine VIN or OEM code) is needed to pick the correct CRIN4 variant and nozzle type.

2. Product Model List