Exam Question
Fuel injector needle valves are found to be seizing frequently Explain;
(a) The effects on the engine operation (8)
(b) The probable causes and remedial actions to be taken (8)
Class 4 (4th Engineer)
MEP
📅 Sep 2022
Reference Answer
### (a) The Effects on the Engine Operation (8 Marks)
Seizing of a fuel injector needle valve can manifest in several states, each with distinct and detrimental effects on engine operation. The primary states are seized shut, seized partially open, and seized fully open.
**1. Injector Needle Seized in 'Shut' Position:**
* **Loss of Power:** No fuel is injected into the cylinder, resulting in a complete loss of power contribution from that unit. The cylinder effectively becomes a parasitic load, being driven by the others.
Seizing of a fuel injector needle valve can manifest in several states, each with distinct and detrimental effects on engine operation. The primary states are seized shut, seized partially open, and seized fully open.
**1. Injector Needle Seized in 'Shut' Position:**
* **Loss of Power:** No fuel is injected into the cylinder, resulting in a complete loss of power contribution from that unit. The cylinder effectively becomes a parasitic load, being driven by the others.
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