Exam Question
(a) Describe how fuel injector components deteriorate with time? (6)
(b) What are effects of deterioration of fuel injector components? (6)
(c) What are the signs of a bad injector? (4)
Class 4 (4th Engineer)
MEKM
📅 Jun 2025
Reference Answer
### (a) Description of Fuel Injector Component Deterioration (6 Marks)
Fuel injector components in marine diesel engines operate under extreme pressure and temperature, leading to deterioration through several mechanisms, primarily driven by fuel quality (especially HFO) and operational stresses.
1. **Abrasive and Erosive Wear**:
* **Abrasive Wear**: Heavy Fuel Oil (HFO) often contains hard, abrasive catalytic fines (Aluminum and Silicon oxides) remaining from the refining process. These particles are harder than the injector materials and cause severe wear on the needle valve and its seat, as well as the nozzle guide. This wear increases clearances, leading to internal leakage and a reduction in injection pressure.
Fuel injector components in marine diesel engines operate under extreme pressure and temperature, leading to deterioration through several mechanisms, primarily driven by fuel quality (especially HFO) and operational stresses.
1. **Abrasive and Erosive Wear**:
* **Abrasive Wear**: Heavy Fuel Oil (HFO) often contains hard, abrasive catalytic fines (Aluminum and Silicon oxides) remaining from the refining process. These particles are harder than the injector materials and cause severe wear on the needle valve and its seat, as well as the nozzle guide. This wear increases clearances, leading to internal leakage and a reduction in injection pressure.
Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.
Prepare on Android — MeoMock on Google Play