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 minimum cetane number typically required for diesel fuel used in locomotive engines?
Answer: 40
A cetane number of at least 40 is required for reliable ignition in locomotive diesel engines; higher cetane improves cold-start performance and reduces combustion noise.
What does water in the fuel system primarily cause in a diesel locomotive?
Answer: Injector seizure, corrosion, and microbial growth
Water promotes corrosion of metal fuel system components, can seize closely-toleranced injection parts, and supports microbial growth that clogs filters.
Which instrument alerts the engineer to excessively low fuel oil pressure during operation?
Answer: The fuel oil pressure alarm and indicator light
The fuel oil pressure alarm activates when pressure drops below the safe operating threshold, warning the engineer of potential fuel starvation.
How does biodiesel blending (B20) affect cold-weather operability of locomotive fuel systems?
Answer: It raises the cloud point, increasing risk of fuel gelling at low temperatures
Biodiesel has a higher cloud point than petroleum diesel, meaning B20 blends can begin to gel at warmer temperatures, potentially plugging filters in cold weather.
What action should an engineer take if the fuel level gauge shows empty but the locomotive is still running?
Answer: Stop the locomotive safely and report the gauge as potentially faulty or tank as critically low
An empty fuel gauge requires the engineer to treat the condition as critical — stop safely, report it, and do not risk running dry, which can damage injection components.
What does the term 'injection timing' refer to in a diesel locomotive engine?
Answer: The point in the piston's compression stroke when fuel is injected
Injection timing defines the precise crankshaft angle at which fuel is delivered into the cylinder, affecting power output, fuel efficiency, and exhaust emissions.
Which condition would cause a diesel locomotive to hunt (surge) at constant throttle?
Answer: Unstable fuel pressure from a failing supply pump or dirty filter
Hunting is caused by inconsistent fuel supply — a failing transfer pump or partially blocked filter delivers uneven fuel pressure, making the governor oscillate.