Fuel Systems & Injection Flashcards
7 cards from real LEC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Fuel Systems & Injection flashcards as text
What is the role of the secondary (final) fuel filter in a locomotive fuel system?
Answer: To trap fine particles that passed the primary filter before reaching the injectors
The secondary filter captures microscopic contaminants that bypassed the primary filter, protecting the precision-machined injectors from abrasive wear.
In cold weather, what additive is commonly used to prevent diesel fuel from gelling in locomotive fuel systems?
Answer: Anti-gel (pour point depressant) additive
Anti-gel or pour point depressant additives disrupt wax crystal formation in cold diesel fuel, keeping it fluid enough to flow through filters and lines.
What does the differential pressure indicator on a fuel filter housing signal when it activates?
Answer: The filter element is loaded and requires replacement
A differential pressure indicator trips when the pressure drop across the filter exceeds a set limit, indicating the element is clogged and needs changing.
What type of seal is critical between the injector body and the cylinder head to prevent combustion gases from entering the fuel return circuit?
Answer: Copper or steel crush washer (nozzle sealing washer)
A copper or steel crush washer at the injector tip seats against the cylinder head, forming a gas-tight seal that prevents high-pressure combustion gases from leaking into the low-pressure return circuit.
If a locomotive engineer smells diesel fuel in the cab during operation, what is the correct immediate action?
Answer: Stop the locomotive, secure it, and report the fuel odor before investigation
Fuel odor in the cab is a fire hazard and requires immediately stopping the locomotive, securing it, and reporting the condition for inspection before further movement.
What is the function of the fuel transfer (supply) pump in relation to the injection pump?
Answer: It lifts fuel from the tank and delivers it at low pressure to the injection pump inlet
The transfer pump provides a continuous low-pressure fuel supply to keep the injection pump inlet flooded, preventing cavitation and ensuring consistent injection pump performance.
Which FRA regulation requires locomotive fuel tanks to meet specific capacity and structural integrity standards?
Answer: 49 CFR Part 229
49 CFR Part 229 (Railroad Locomotive Safety Standards) specifies requirements for fuel tanks including capacity markings, fill openings, and structural protection against leakage.