Subtopic: I.C. engine systems – fuel, cooling, lubrication, ignition, electrical, intake and exhaust
Question Statement:
Direct-injection (DI) open combustion chamber tractor diesel engines typically employ which type of fuel injector nozzle?
Options:
(A) Pintle type nozzle
(B) Multi-hole orifice nozzle
(C) Poppet valve nozzle
(D) Capillary tube nozzle
Answer Key:
B
Step-by-Step Solution & Explanation
- **Direct Injection (DI) Nozzle Type:**
- In DI engines with shallow or toroidal piston bowl chambers, air motion is primarily moderate swirl and squish.
- High penetration and wide spray distribution are achieved using **multi-hole nozzles** (typically 4 to 6 spray holes of diameter $0.2\text{--}0.3\text{ mm}$) at high injection pressures ($200\text{--}300\text{ bar}$).
- Pintle nozzles are used in indirect injection (IDI) pre-combustion chambers.